Loading...
1# Select 32 or 64 bit
2config 64BIT
3 bool "64-bit kernel" if ARCH = "x86"
4 default ARCH = "x86_64"
5 ---help---
6 Say yes to build a 64-bit kernel - formerly known as x86_64
7 Say no to build a 32-bit kernel - formerly known as i386
8
9config X86_32
10 def_bool !64BIT
11 select CLKSRC_I8253
12
13config X86_64
14 def_bool 64BIT
15 select X86_DEV_DMA_OPS
16
17### Arch settings
18config X86
19 def_bool y
20 select HAVE_AOUT if X86_32
21 select HAVE_UNSTABLE_SCHED_CLOCK
22 select HAVE_IDE
23 select HAVE_OPROFILE
24 select HAVE_PCSPKR_PLATFORM
25 select HAVE_PERF_EVENTS
26 select HAVE_IRQ_WORK
27 select HAVE_IOREMAP_PROT
28 select HAVE_KPROBES
29 select HAVE_MEMBLOCK
30 select HAVE_MEMBLOCK_NODE_MAP
31 select ARCH_DISCARD_MEMBLOCK
32 select ARCH_WANT_OPTIONAL_GPIOLIB
33 select ARCH_WANT_FRAME_POINTERS
34 select HAVE_DMA_ATTRS
35 select HAVE_DMA_CONTIGUOUS if !SWIOTLB
36 select HAVE_KRETPROBES
37 select HAVE_OPTPROBES
38 select HAVE_FTRACE_MCOUNT_RECORD
39 select HAVE_C_RECORDMCOUNT
40 select HAVE_DYNAMIC_FTRACE
41 select HAVE_FUNCTION_TRACER
42 select HAVE_FUNCTION_GRAPH_TRACER
43 select HAVE_FUNCTION_GRAPH_FP_TEST
44 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
45 select HAVE_SYSCALL_TRACEPOINTS
46 select HAVE_KVM
47 select HAVE_ARCH_KGDB
48 select HAVE_ARCH_TRACEHOOK
49 select HAVE_GENERIC_DMA_COHERENT if X86_32
50 select HAVE_EFFICIENT_UNALIGNED_ACCESS
51 select USER_STACKTRACE_SUPPORT
52 select HAVE_REGS_AND_STACK_ACCESS_API
53 select HAVE_DMA_API_DEBUG
54 select HAVE_KERNEL_GZIP
55 select HAVE_KERNEL_BZIP2
56 select HAVE_KERNEL_LZMA
57 select HAVE_KERNEL_XZ
58 select HAVE_KERNEL_LZO
59 select HAVE_HW_BREAKPOINT
60 select HAVE_MIXED_BREAKPOINTS_REGS
61 select PERF_EVENTS
62 select HAVE_PERF_EVENTS_NMI
63 select ANON_INODES
64 select HAVE_ALIGNED_STRUCT_PAGE if SLUB && !M386
65 select HAVE_CMPXCHG_LOCAL if !M386
66 select HAVE_CMPXCHG_DOUBLE
67 select HAVE_ARCH_KMEMCHECK
68 select HAVE_USER_RETURN_NOTIFIER
69 select ARCH_BINFMT_ELF_RANDOMIZE_PIE
70 select HAVE_ARCH_JUMP_LABEL
71 select HAVE_TEXT_POKE_SMP
72 select HAVE_GENERIC_HARDIRQS
73 select SPARSE_IRQ
74 select GENERIC_FIND_FIRST_BIT
75 select GENERIC_IRQ_PROBE
76 select GENERIC_PENDING_IRQ if SMP
77 select GENERIC_IRQ_SHOW
78 select GENERIC_CLOCKEVENTS_MIN_ADJUST
79 select IRQ_FORCED_THREADING
80 select USE_GENERIC_SMP_HELPERS if SMP
81 select HAVE_BPF_JIT if X86_64
82 select CLKEVT_I8253
83 select ARCH_HAVE_NMI_SAFE_CMPXCHG
84 select GENERIC_IOMAP
85 select DCACHE_WORD_ACCESS
86 select GENERIC_SMP_IDLE_THREAD
87 select HAVE_ARCH_SECCOMP_FILTER
88 select BUILDTIME_EXTABLE_SORT
89 select GENERIC_CMOS_UPDATE
90 select CLOCKSOURCE_WATCHDOG
91 select GENERIC_CLOCKEVENTS
92 select ARCH_CLOCKSOURCE_DATA if X86_64
93 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
94 select GENERIC_TIME_VSYSCALL if X86_64
95 select KTIME_SCALAR if X86_32
96 select GENERIC_STRNCPY_FROM_USER
97 select GENERIC_STRNLEN_USER
98
99config INSTRUCTION_DECODER
100 def_bool (KPROBES || PERF_EVENTS || UPROBES)
101
102config OUTPUT_FORMAT
103 string
104 default "elf32-i386" if X86_32
105 default "elf64-x86-64" if X86_64
106
107config ARCH_DEFCONFIG
108 string
109 default "arch/x86/configs/i386_defconfig" if X86_32
110 default "arch/x86/configs/x86_64_defconfig" if X86_64
111
112config LOCKDEP_SUPPORT
113 def_bool y
114
115config STACKTRACE_SUPPORT
116 def_bool y
117
118config HAVE_LATENCYTOP_SUPPORT
119 def_bool y
120
121config MMU
122 def_bool y
123
124config SBUS
125 bool
126
127config NEED_DMA_MAP_STATE
128 def_bool (X86_64 || INTEL_IOMMU || DMA_API_DEBUG)
129
130config NEED_SG_DMA_LENGTH
131 def_bool y
132
133config GENERIC_ISA_DMA
134 def_bool ISA_DMA_API
135
136config GENERIC_BUG
137 def_bool y
138 depends on BUG
139 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
140
141config GENERIC_BUG_RELATIVE_POINTERS
142 bool
143
144config GENERIC_HWEIGHT
145 def_bool y
146
147config GENERIC_GPIO
148 bool
149
150config ARCH_MAY_HAVE_PC_FDC
151 def_bool ISA_DMA_API
152
153config RWSEM_GENERIC_SPINLOCK
154 def_bool !X86_XADD
155
156config RWSEM_XCHGADD_ALGORITHM
157 def_bool X86_XADD
158
159config GENERIC_CALIBRATE_DELAY
160 def_bool y
161
162config ARCH_HAS_CPU_RELAX
163 def_bool y
164
165config ARCH_HAS_DEFAULT_IDLE
166 def_bool y
167
168config ARCH_HAS_CACHE_LINE_SIZE
169 def_bool y
170
171config ARCH_HAS_CPU_AUTOPROBE
172 def_bool y
173
174config HAVE_SETUP_PER_CPU_AREA
175 def_bool y
176
177config NEED_PER_CPU_EMBED_FIRST_CHUNK
178 def_bool y
179
180config NEED_PER_CPU_PAGE_FIRST_CHUNK
181 def_bool y
182
183config ARCH_HIBERNATION_POSSIBLE
184 def_bool y
185
186config ARCH_SUSPEND_POSSIBLE
187 def_bool y
188
189config ZONE_DMA32
190 bool
191 default X86_64
192
193config AUDIT_ARCH
194 bool
195 default X86_64
196
197config ARCH_SUPPORTS_OPTIMIZED_INLINING
198 def_bool y
199
200config ARCH_SUPPORTS_DEBUG_PAGEALLOC
201 def_bool y
202
203config HAVE_INTEL_TXT
204 def_bool y
205 depends on EXPERIMENTAL && INTEL_IOMMU && ACPI
206
207config X86_32_SMP
208 def_bool y
209 depends on X86_32 && SMP
210
211config X86_64_SMP
212 def_bool y
213 depends on X86_64 && SMP
214
215config X86_HT
216 def_bool y
217 depends on SMP
218
219config X86_32_LAZY_GS
220 def_bool y
221 depends on X86_32 && !CC_STACKPROTECTOR
222
223config ARCH_HWEIGHT_CFLAGS
224 string
225 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
226 default "-fcall-saved-rdi -fcall-saved-rsi -fcall-saved-rdx -fcall-saved-rcx -fcall-saved-r8 -fcall-saved-r9 -fcall-saved-r10 -fcall-saved-r11" if X86_64
227
228config ARCH_CPU_PROBE_RELEASE
229 def_bool y
230 depends on HOTPLUG_CPU
231
232config ARCH_SUPPORTS_UPROBES
233 def_bool y
234
235source "init/Kconfig"
236source "kernel/Kconfig.freezer"
237
238menu "Processor type and features"
239
240config ZONE_DMA
241 bool "DMA memory allocation support" if EXPERT
242 default y
243 help
244 DMA memory allocation support allows devices with less than 32-bit
245 addressing to allocate within the first 16MB of address space.
246 Disable if no such devices will be used.
247
248 If unsure, say Y.
249
250config SMP
251 bool "Symmetric multi-processing support"
252 ---help---
253 This enables support for systems with more than one CPU. If you have
254 a system with only one CPU, like most personal computers, say N. If
255 you have a system with more than one CPU, say Y.
256
257 If you say N here, the kernel will run on single and multiprocessor
258 machines, but will use only one CPU of a multiprocessor machine. If
259 you say Y here, the kernel will run on many, but not all,
260 singleprocessor machines. On a singleprocessor machine, the kernel
261 will run faster if you say N here.
262
263 Note that if you say Y here and choose architecture "586" or
264 "Pentium" under "Processor family", the kernel will not work on 486
265 architectures. Similarly, multiprocessor kernels for the "PPro"
266 architecture may not work on all Pentium based boards.
267
268 People using multiprocessor machines who say Y here should also say
269 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
270 Management" code will be disabled if you say Y here.
271
272 See also <file:Documentation/x86/i386/IO-APIC.txt>,
273 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
274 <http://www.tldp.org/docs.html#howto>.
275
276 If you don't know what to do here, say N.
277
278config X86_X2APIC
279 bool "Support x2apic"
280 depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
281 ---help---
282 This enables x2apic support on CPUs that have this feature.
283
284 This allows 32-bit apic IDs (so it can support very large systems),
285 and accesses the local apic via MSRs not via mmio.
286
287 If you don't know what to do here, say N.
288
289config X86_MPPARSE
290 bool "Enable MPS table" if ACPI
291 default y
292 depends on X86_LOCAL_APIC
293 ---help---
294 For old smp systems that do not have proper acpi support. Newer systems
295 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
296
297config X86_BIGSMP
298 bool "Support for big SMP systems with more than 8 CPUs"
299 depends on X86_32 && SMP
300 ---help---
301 This option is needed for the systems that have more than 8 CPUs
302
303if X86_32
304config X86_EXTENDED_PLATFORM
305 bool "Support for extended (non-PC) x86 platforms"
306 default y
307 ---help---
308 If you disable this option then the kernel will only support
309 standard PC platforms. (which covers the vast majority of
310 systems out there.)
311
312 If you enable this option then you'll be able to select support
313 for the following (non-PC) 32 bit x86 platforms:
314 AMD Elan
315 NUMAQ (IBM/Sequent)
316 RDC R-321x SoC
317 SGI 320/540 (Visual Workstation)
318 STA2X11-based (e.g. Northville)
319 Summit/EXA (IBM x440)
320 Unisys ES7000 IA32 series
321 Moorestown MID devices
322
323 If you have one of these systems, or if you want to build a
324 generic distribution kernel, say Y here - otherwise say N.
325endif
326
327if X86_64
328config X86_EXTENDED_PLATFORM
329 bool "Support for extended (non-PC) x86 platforms"
330 default y
331 ---help---
332 If you disable this option then the kernel will only support
333 standard PC platforms. (which covers the vast majority of
334 systems out there.)
335
336 If you enable this option then you'll be able to select support
337 for the following (non-PC) 64 bit x86 platforms:
338 Numascale NumaChip
339 ScaleMP vSMP
340 SGI Ultraviolet
341
342 If you have one of these systems, or if you want to build a
343 generic distribution kernel, say Y here - otherwise say N.
344endif
345# This is an alphabetically sorted list of 64 bit extended platforms
346# Please maintain the alphabetic order if and when there are additions
347config X86_NUMACHIP
348 bool "Numascale NumaChip"
349 depends on X86_64
350 depends on X86_EXTENDED_PLATFORM
351 depends on NUMA
352 depends on SMP
353 depends on X86_X2APIC
354 ---help---
355 Adds support for Numascale NumaChip large-SMP systems. Needed to
356 enable more than ~168 cores.
357 If you don't have one of these, you should say N here.
358
359config X86_VSMP
360 bool "ScaleMP vSMP"
361 select PARAVIRT_GUEST
362 select PARAVIRT
363 depends on X86_64 && PCI
364 depends on X86_EXTENDED_PLATFORM
365 depends on SMP
366 ---help---
367 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
368 supposed to run on these EM64T-based machines. Only choose this option
369 if you have one of these machines.
370
371config X86_UV
372 bool "SGI Ultraviolet"
373 depends on X86_64
374 depends on X86_EXTENDED_PLATFORM
375 depends on NUMA
376 depends on X86_X2APIC
377 ---help---
378 This option is needed in order to support SGI Ultraviolet systems.
379 If you don't have one of these, you should say N here.
380
381# Following is an alphabetically sorted list of 32 bit extended platforms
382# Please maintain the alphabetic order if and when there are additions
383
384config X86_INTEL_CE
385 bool "CE4100 TV platform"
386 depends on PCI
387 depends on PCI_GODIRECT
388 depends on X86_32
389 depends on X86_EXTENDED_PLATFORM
390 select X86_REBOOTFIXUPS
391 select OF
392 select OF_EARLY_FLATTREE
393 select IRQ_DOMAIN
394 ---help---
395 Select for the Intel CE media processor (CE4100) SOC.
396 This option compiles in support for the CE4100 SOC for settop
397 boxes and media devices.
398
399config X86_WANT_INTEL_MID
400 bool "Intel MID platform support"
401 depends on X86_32
402 depends on X86_EXTENDED_PLATFORM
403 ---help---
404 Select to build a kernel capable of supporting Intel MID platform
405 systems which do not have the PCI legacy interfaces (Moorestown,
406 Medfield). If you are building for a PC class system say N here.
407
408if X86_WANT_INTEL_MID
409
410config X86_INTEL_MID
411 bool
412
413config X86_MDFLD
414 bool "Medfield MID platform"
415 depends on PCI
416 depends on PCI_GOANY
417 depends on X86_IO_APIC
418 select X86_INTEL_MID
419 select SFI
420 select DW_APB_TIMER
421 select APB_TIMER
422 select I2C
423 select SPI
424 select INTEL_SCU_IPC
425 select X86_PLATFORM_DEVICES
426 select MFD_INTEL_MSIC
427 ---help---
428 Medfield is Intel's Low Power Intel Architecture (LPIA) based Moblin
429 Internet Device(MID) platform.
430 Unlike standard x86 PCs, Medfield does not have many legacy devices
431 nor standard legacy replacement devices/features. e.g. Medfield does
432 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
433
434endif
435
436config X86_RDC321X
437 bool "RDC R-321x SoC"
438 depends on X86_32
439 depends on X86_EXTENDED_PLATFORM
440 select M486
441 select X86_REBOOTFIXUPS
442 ---help---
443 This option is needed for RDC R-321x system-on-chip, also known
444 as R-8610-(G).
445 If you don't have one of these chips, you should say N here.
446
447config X86_32_NON_STANDARD
448 bool "Support non-standard 32-bit SMP architectures"
449 depends on X86_32 && SMP
450 depends on X86_EXTENDED_PLATFORM
451 ---help---
452 This option compiles in the NUMAQ, Summit, bigsmp, ES7000,
453 STA2X11, default subarchitectures. It is intended for a generic
454 binary kernel. If you select them all, kernel will probe it
455 one by one and will fallback to default.
456
457# Alphabetically sorted list of Non standard 32 bit platforms
458
459config X86_NUMAQ
460 bool "NUMAQ (IBM/Sequent)"
461 depends on X86_32_NON_STANDARD
462 depends on PCI
463 select NUMA
464 select X86_MPPARSE
465 ---help---
466 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
467 NUMA multiquad box. This changes the way that processors are
468 bootstrapped, and uses Clustered Logical APIC addressing mode instead
469 of Flat Logical. You will need a new lynxer.elf file to flash your
470 firmware with - send email to <Martin.Bligh@us.ibm.com>.
471
472config X86_SUPPORTS_MEMORY_FAILURE
473 def_bool y
474 # MCE code calls memory_failure():
475 depends on X86_MCE
476 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
477 depends on !X86_NUMAQ
478 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
479 depends on X86_64 || !SPARSEMEM
480 select ARCH_SUPPORTS_MEMORY_FAILURE
481
482config X86_VISWS
483 bool "SGI 320/540 (Visual Workstation)"
484 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
485 depends on X86_32_NON_STANDARD
486 ---help---
487 The SGI Visual Workstation series is an IA32-based workstation
488 based on SGI systems chips with some legacy PC hardware attached.
489
490 Say Y here to create a kernel to run on the SGI 320 or 540.
491
492 A kernel compiled for the Visual Workstation will run on general
493 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
494
495config STA2X11
496 bool "STA2X11 Companion Chip Support"
497 depends on X86_32_NON_STANDARD && PCI
498 select X86_DEV_DMA_OPS
499 select X86_DMA_REMAP
500 select SWIOTLB
501 select MFD_STA2X11
502 select ARCH_REQUIRE_GPIOLIB
503 default n
504 ---help---
505 This adds support for boards based on the STA2X11 IO-Hub,
506 a.k.a. "ConneXt". The chip is used in place of the standard
507 PC chipset, so all "standard" peripherals are missing. If this
508 option is selected the kernel will still be able to boot on
509 standard PC machines.
510
511config X86_SUMMIT
512 bool "Summit/EXA (IBM x440)"
513 depends on X86_32_NON_STANDARD
514 ---help---
515 This option is needed for IBM systems that use the Summit/EXA chipset.
516 In particular, it is needed for the x440.
517
518config X86_ES7000
519 bool "Unisys ES7000 IA32 series"
520 depends on X86_32_NON_STANDARD && X86_BIGSMP
521 ---help---
522 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
523 supposed to run on an IA32-based Unisys ES7000 system.
524
525config X86_32_IRIS
526 tristate "Eurobraille/Iris poweroff module"
527 depends on X86_32
528 ---help---
529 The Iris machines from EuroBraille do not have APM or ACPI support
530 to shut themselves down properly. A special I/O sequence is
531 needed to do so, which is what this module does at
532 kernel shutdown.
533
534 This is only for Iris machines from EuroBraille.
535
536 If unused, say N.
537
538config SCHED_OMIT_FRAME_POINTER
539 def_bool y
540 prompt "Single-depth WCHAN output"
541 depends on X86
542 ---help---
543 Calculate simpler /proc/<PID>/wchan values. If this option
544 is disabled then wchan values will recurse back to the
545 caller function. This provides more accurate wchan values,
546 at the expense of slightly more scheduling overhead.
547
548 If in doubt, say "Y".
549
550menuconfig PARAVIRT_GUEST
551 bool "Paravirtualized guest support"
552 ---help---
553 Say Y here to get to see options related to running Linux under
554 various hypervisors. This option alone does not add any kernel code.
555
556 If you say N, all options in this submenu will be skipped and disabled.
557
558if PARAVIRT_GUEST
559
560config PARAVIRT_TIME_ACCOUNTING
561 bool "Paravirtual steal time accounting"
562 select PARAVIRT
563 default n
564 ---help---
565 Select this option to enable fine granularity task steal time
566 accounting. Time spent executing other tasks in parallel with
567 the current vCPU is discounted from the vCPU power. To account for
568 that, there can be a small performance impact.
569
570 If in doubt, say N here.
571
572source "arch/x86/xen/Kconfig"
573
574config KVM_CLOCK
575 bool "KVM paravirtualized clock"
576 select PARAVIRT
577 select PARAVIRT_CLOCK
578 ---help---
579 Turning on this option will allow you to run a paravirtualized clock
580 when running over the KVM hypervisor. Instead of relying on a PIT
581 (or probably other) emulation by the underlying device model, the host
582 provides the guest with timing infrastructure such as time of day, and
583 system time
584
585config KVM_GUEST
586 bool "KVM Guest support"
587 select PARAVIRT
588 ---help---
589 This option enables various optimizations for running under the KVM
590 hypervisor.
591
592source "arch/x86/lguest/Kconfig"
593
594config PARAVIRT
595 bool "Enable paravirtualization code"
596 ---help---
597 This changes the kernel so it can modify itself when it is run
598 under a hypervisor, potentially improving performance significantly
599 over full virtualization. However, when run without a hypervisor
600 the kernel is theoretically slower and slightly larger.
601
602config PARAVIRT_SPINLOCKS
603 bool "Paravirtualization layer for spinlocks"
604 depends on PARAVIRT && SMP && EXPERIMENTAL
605 ---help---
606 Paravirtualized spinlocks allow a pvops backend to replace the
607 spinlock implementation with something virtualization-friendly
608 (for example, block the virtual CPU rather than spinning).
609
610 Unfortunately the downside is an up to 5% performance hit on
611 native kernels, with various workloads.
612
613 If you are unsure how to answer this question, answer N.
614
615config PARAVIRT_CLOCK
616 bool
617
618endif
619
620config PARAVIRT_DEBUG
621 bool "paravirt-ops debugging"
622 depends on PARAVIRT && DEBUG_KERNEL
623 ---help---
624 Enable to debug paravirt_ops internals. Specifically, BUG if
625 a paravirt_op is missing when it is called.
626
627config NO_BOOTMEM
628 def_bool y
629
630config MEMTEST
631 bool "Memtest"
632 ---help---
633 This option adds a kernel parameter 'memtest', which allows memtest
634 to be set.
635 memtest=0, mean disabled; -- default
636 memtest=1, mean do 1 test pattern;
637 ...
638 memtest=4, mean do 4 test patterns.
639 If you are unsure how to answer this question, answer N.
640
641config X86_SUMMIT_NUMA
642 def_bool y
643 depends on X86_32 && NUMA && X86_32_NON_STANDARD
644
645config X86_CYCLONE_TIMER
646 def_bool y
647 depends on X86_SUMMIT
648
649source "arch/x86/Kconfig.cpu"
650
651config HPET_TIMER
652 def_bool X86_64
653 prompt "HPET Timer Support" if X86_32
654 ---help---
655 Use the IA-PC HPET (High Precision Event Timer) to manage
656 time in preference to the PIT and RTC, if a HPET is
657 present.
658 HPET is the next generation timer replacing legacy 8254s.
659 The HPET provides a stable time base on SMP
660 systems, unlike the TSC, but it is more expensive to access,
661 as it is off-chip. You can find the HPET spec at
662 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
663
664 You can safely choose Y here. However, HPET will only be
665 activated if the platform and the BIOS support this feature.
666 Otherwise the 8254 will be used for timing services.
667
668 Choose N to continue using the legacy 8254 timer.
669
670config HPET_EMULATE_RTC
671 def_bool y
672 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
673
674config APB_TIMER
675 def_bool y if X86_INTEL_MID
676 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
677 select DW_APB_TIMER
678 depends on X86_INTEL_MID && SFI
679 help
680 APB timer is the replacement for 8254, HPET on X86 MID platforms.
681 The APBT provides a stable time base on SMP
682 systems, unlike the TSC, but it is more expensive to access,
683 as it is off-chip. APB timers are always running regardless of CPU
684 C states, they are used as per CPU clockevent device when possible.
685
686# Mark as expert because too many people got it wrong.
687# The code disables itself when not needed.
688config DMI
689 default y
690 bool "Enable DMI scanning" if EXPERT
691 ---help---
692 Enabled scanning of DMI to identify machine quirks. Say Y
693 here unless you have verified that your setup is not
694 affected by entries in the DMI blacklist. Required by PNP
695 BIOS code.
696
697config GART_IOMMU
698 bool "GART IOMMU support" if EXPERT
699 default y
700 select SWIOTLB
701 depends on X86_64 && PCI && AMD_NB
702 ---help---
703 Support for full DMA access of devices with 32bit memory access only
704 on systems with more than 3GB. This is usually needed for USB,
705 sound, many IDE/SATA chipsets and some other devices.
706 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
707 based hardware IOMMU and a software bounce buffer based IOMMU used
708 on Intel systems and as fallback.
709 The code is only active when needed (enough memory and limited
710 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
711 too.
712
713config CALGARY_IOMMU
714 bool "IBM Calgary IOMMU support"
715 select SWIOTLB
716 depends on X86_64 && PCI && EXPERIMENTAL
717 ---help---
718 Support for hardware IOMMUs in IBM's xSeries x366 and x460
719 systems. Needed to run systems with more than 3GB of memory
720 properly with 32-bit PCI devices that do not support DAC
721 (Double Address Cycle). Calgary also supports bus level
722 isolation, where all DMAs pass through the IOMMU. This
723 prevents them from going anywhere except their intended
724 destination. This catches hard-to-find kernel bugs and
725 mis-behaving drivers and devices that do not use the DMA-API
726 properly to set up their DMA buffers. The IOMMU can be
727 turned off at boot time with the iommu=off parameter.
728 Normally the kernel will make the right choice by itself.
729 If unsure, say Y.
730
731config CALGARY_IOMMU_ENABLED_BY_DEFAULT
732 def_bool y
733 prompt "Should Calgary be enabled by default?"
734 depends on CALGARY_IOMMU
735 ---help---
736 Should Calgary be enabled by default? if you choose 'y', Calgary
737 will be used (if it exists). If you choose 'n', Calgary will not be
738 used even if it exists. If you choose 'n' and would like to use
739 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
740 If unsure, say Y.
741
742# need this always selected by IOMMU for the VIA workaround
743config SWIOTLB
744 def_bool y if X86_64
745 ---help---
746 Support for software bounce buffers used on x86-64 systems
747 which don't have a hardware IOMMU (e.g. the current generation
748 of Intel's x86-64 CPUs). Using this PCI devices which can only
749 access 32-bits of memory can be used on systems with more than
750 3 GB of memory. If unsure, say Y.
751
752config IOMMU_HELPER
753 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
754
755config MAXSMP
756 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
757 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
758 select CPUMASK_OFFSTACK
759 ---help---
760 Enable maximum number of CPUS and NUMA Nodes for this architecture.
761 If unsure, say N.
762
763config NR_CPUS
764 int "Maximum number of CPUs" if SMP && !MAXSMP
765 range 2 8 if SMP && X86_32 && !X86_BIGSMP
766 range 2 512 if SMP && !MAXSMP
767 default "1" if !SMP
768 default "4096" if MAXSMP
769 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
770 default "8" if SMP
771 ---help---
772 This allows you to specify the maximum number of CPUs which this
773 kernel will support. The maximum supported value is 512 and the
774 minimum value which makes sense is 2.
775
776 This is purely to save memory - each supported CPU adds
777 approximately eight kilobytes to the kernel image.
778
779config SCHED_SMT
780 bool "SMT (Hyperthreading) scheduler support"
781 depends on X86_HT
782 ---help---
783 SMT scheduler support improves the CPU scheduler's decision making
784 when dealing with Intel Pentium 4 chips with HyperThreading at a
785 cost of slightly increased overhead in some places. If unsure say
786 N here.
787
788config SCHED_MC
789 def_bool y
790 prompt "Multi-core scheduler support"
791 depends on X86_HT
792 ---help---
793 Multi-core scheduler support improves the CPU scheduler's decision
794 making when dealing with multi-core CPU chips at a cost of slightly
795 increased overhead in some places. If unsure say N here.
796
797config IRQ_TIME_ACCOUNTING
798 bool "Fine granularity task level IRQ time accounting"
799 default n
800 ---help---
801 Select this option to enable fine granularity task irq time
802 accounting. This is done by reading a timestamp on each
803 transitions between softirq and hardirq state, so there can be a
804 small performance impact.
805
806 If in doubt, say N here.
807
808source "kernel/Kconfig.preempt"
809
810config X86_UP_APIC
811 bool "Local APIC support on uniprocessors"
812 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
813 ---help---
814 A local APIC (Advanced Programmable Interrupt Controller) is an
815 integrated interrupt controller in the CPU. If you have a single-CPU
816 system which has a processor with a local APIC, you can say Y here to
817 enable and use it. If you say Y here even though your machine doesn't
818 have a local APIC, then the kernel will still run with no slowdown at
819 all. The local APIC supports CPU-generated self-interrupts (timer,
820 performance counters), and the NMI watchdog which detects hard
821 lockups.
822
823config X86_UP_IOAPIC
824 bool "IO-APIC support on uniprocessors"
825 depends on X86_UP_APIC
826 ---help---
827 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
828 SMP-capable replacement for PC-style interrupt controllers. Most
829 SMP systems and many recent uniprocessor systems have one.
830
831 If you have a single-CPU system with an IO-APIC, you can say Y here
832 to use it. If you say Y here even though your machine doesn't have
833 an IO-APIC, then the kernel will still run with no slowdown at all.
834
835config X86_LOCAL_APIC
836 def_bool y
837 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
838
839config X86_IO_APIC
840 def_bool y
841 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_IOAPIC
842
843config X86_VISWS_APIC
844 def_bool y
845 depends on X86_32 && X86_VISWS
846
847config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
848 bool "Reroute for broken boot IRQs"
849 depends on X86_IO_APIC
850 ---help---
851 This option enables a workaround that fixes a source of
852 spurious interrupts. This is recommended when threaded
853 interrupt handling is used on systems where the generation of
854 superfluous "boot interrupts" cannot be disabled.
855
856 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
857 entry in the chipset's IO-APIC is masked (as, e.g. the RT
858 kernel does during interrupt handling). On chipsets where this
859 boot IRQ generation cannot be disabled, this workaround keeps
860 the original IRQ line masked so that only the equivalent "boot
861 IRQ" is delivered to the CPUs. The workaround also tells the
862 kernel to set up the IRQ handler on the boot IRQ line. In this
863 way only one interrupt is delivered to the kernel. Otherwise
864 the spurious second interrupt may cause the kernel to bring
865 down (vital) interrupt lines.
866
867 Only affects "broken" chipsets. Interrupt sharing may be
868 increased on these systems.
869
870config X86_MCE
871 bool "Machine Check / overheating reporting"
872 ---help---
873 Machine Check support allows the processor to notify the
874 kernel if it detects a problem (e.g. overheating, data corruption).
875 The action the kernel takes depends on the severity of the problem,
876 ranging from warning messages to halting the machine.
877
878config X86_MCE_INTEL
879 def_bool y
880 prompt "Intel MCE features"
881 depends on X86_MCE && X86_LOCAL_APIC
882 ---help---
883 Additional support for intel specific MCE features such as
884 the thermal monitor.
885
886config X86_MCE_AMD
887 def_bool y
888 prompt "AMD MCE features"
889 depends on X86_MCE && X86_LOCAL_APIC
890 ---help---
891 Additional support for AMD specific MCE features such as
892 the DRAM Error Threshold.
893
894config X86_ANCIENT_MCE
895 bool "Support for old Pentium 5 / WinChip machine checks"
896 depends on X86_32 && X86_MCE
897 ---help---
898 Include support for machine check handling on old Pentium 5 or WinChip
899 systems. These typically need to be enabled explicitely on the command
900 line.
901
902config X86_MCE_THRESHOLD
903 depends on X86_MCE_AMD || X86_MCE_INTEL
904 def_bool y
905
906config X86_MCE_INJECT
907 depends on X86_MCE
908 tristate "Machine check injector support"
909 ---help---
910 Provide support for injecting machine checks for testing purposes.
911 If you don't know what a machine check is and you don't do kernel
912 QA it is safe to say n.
913
914config X86_THERMAL_VECTOR
915 def_bool y
916 depends on X86_MCE_INTEL
917
918config VM86
919 bool "Enable VM86 support" if EXPERT
920 default y
921 depends on X86_32
922 ---help---
923 This option is required by programs like DOSEMU to run 16-bit legacy
924 code on X86 processors. It also may be needed by software like
925 XFree86 to initialize some video cards via BIOS. Disabling this
926 option saves about 6k.
927
928config TOSHIBA
929 tristate "Toshiba Laptop support"
930 depends on X86_32
931 ---help---
932 This adds a driver to safely access the System Management Mode of
933 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
934 not work on models with a Phoenix BIOS. The System Management Mode
935 is used to set the BIOS and power saving options on Toshiba portables.
936
937 For information on utilities to make use of this driver see the
938 Toshiba Linux utilities web site at:
939 <http://www.buzzard.org.uk/toshiba/>.
940
941 Say Y if you intend to run this kernel on a Toshiba portable.
942 Say N otherwise.
943
944config I8K
945 tristate "Dell laptop support"
946 select HWMON
947 ---help---
948 This adds a driver to safely access the System Management Mode
949 of the CPU on the Dell Inspiron 8000. The System Management Mode
950 is used to read cpu temperature and cooling fan status and to
951 control the fans on the I8K portables.
952
953 This driver has been tested only on the Inspiron 8000 but it may
954 also work with other Dell laptops. You can force loading on other
955 models by passing the parameter `force=1' to the module. Use at
956 your own risk.
957
958 For information on utilities to make use of this driver see the
959 I8K Linux utilities web site at:
960 <http://people.debian.org/~dz/i8k/>
961
962 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
963 Say N otherwise.
964
965config X86_REBOOTFIXUPS
966 bool "Enable X86 board specific fixups for reboot"
967 depends on X86_32
968 ---help---
969 This enables chipset and/or board specific fixups to be done
970 in order to get reboot to work correctly. This is only needed on
971 some combinations of hardware and BIOS. The symptom, for which
972 this config is intended, is when reboot ends with a stalled/hung
973 system.
974
975 Currently, the only fixup is for the Geode machines using
976 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
977
978 Say Y if you want to enable the fixup. Currently, it's safe to
979 enable this option even if you don't need it.
980 Say N otherwise.
981
982config MICROCODE
983 tristate "/dev/cpu/microcode - microcode support"
984 select FW_LOADER
985 ---help---
986 If you say Y here, you will be able to update the microcode on
987 certain Intel and AMD processors. The Intel support is for the
988 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
989 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
990 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
991 You will obviously need the actual microcode binary data itself
992 which is not shipped with the Linux kernel.
993
994 This option selects the general module only, you need to select
995 at least one vendor specific module as well.
996
997 To compile this driver as a module, choose M here: the
998 module will be called microcode.
999
1000config MICROCODE_INTEL
1001 bool "Intel microcode patch loading support"
1002 depends on MICROCODE
1003 default MICROCODE
1004 select FW_LOADER
1005 ---help---
1006 This options enables microcode patch loading support for Intel
1007 processors.
1008
1009 For latest news and information on obtaining all the required
1010 Intel ingredients for this driver, check:
1011 <http://www.urbanmyth.org/microcode/>.
1012
1013config MICROCODE_AMD
1014 bool "AMD microcode patch loading support"
1015 depends on MICROCODE
1016 select FW_LOADER
1017 ---help---
1018 If you select this option, microcode patch loading support for AMD
1019 processors will be enabled.
1020
1021config MICROCODE_OLD_INTERFACE
1022 def_bool y
1023 depends on MICROCODE
1024
1025config X86_MSR
1026 tristate "/dev/cpu/*/msr - Model-specific register support"
1027 ---help---
1028 This device gives privileged processes access to the x86
1029 Model-Specific Registers (MSRs). It is a character device with
1030 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1031 MSR accesses are directed to a specific CPU on multi-processor
1032 systems.
1033
1034config X86_CPUID
1035 tristate "/dev/cpu/*/cpuid - CPU information support"
1036 ---help---
1037 This device gives processes access to the x86 CPUID instruction to
1038 be executed on a specific processor. It is a character device
1039 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1040 /dev/cpu/31/cpuid.
1041
1042choice
1043 prompt "High Memory Support"
1044 default HIGHMEM64G if X86_NUMAQ
1045 default HIGHMEM4G
1046 depends on X86_32
1047
1048config NOHIGHMEM
1049 bool "off"
1050 depends on !X86_NUMAQ
1051 ---help---
1052 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1053 However, the address space of 32-bit x86 processors is only 4
1054 Gigabytes large. That means that, if you have a large amount of
1055 physical memory, not all of it can be "permanently mapped" by the
1056 kernel. The physical memory that's not permanently mapped is called
1057 "high memory".
1058
1059 If you are compiling a kernel which will never run on a machine with
1060 more than 1 Gigabyte total physical RAM, answer "off" here (default
1061 choice and suitable for most users). This will result in a "3GB/1GB"
1062 split: 3GB are mapped so that each process sees a 3GB virtual memory
1063 space and the remaining part of the 4GB virtual memory space is used
1064 by the kernel to permanently map as much physical memory as
1065 possible.
1066
1067 If the machine has between 1 and 4 Gigabytes physical RAM, then
1068 answer "4GB" here.
1069
1070 If more than 4 Gigabytes is used then answer "64GB" here. This
1071 selection turns Intel PAE (Physical Address Extension) mode on.
1072 PAE implements 3-level paging on IA32 processors. PAE is fully
1073 supported by Linux, PAE mode is implemented on all recent Intel
1074 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1075 then the kernel will not boot on CPUs that don't support PAE!
1076
1077 The actual amount of total physical memory will either be
1078 auto detected or can be forced by using a kernel command line option
1079 such as "mem=256M". (Try "man bootparam" or see the documentation of
1080 your boot loader (lilo or loadlin) about how to pass options to the
1081 kernel at boot time.)
1082
1083 If unsure, say "off".
1084
1085config HIGHMEM4G
1086 bool "4GB"
1087 depends on !X86_NUMAQ
1088 ---help---
1089 Select this if you have a 32-bit processor and between 1 and 4
1090 gigabytes of physical RAM.
1091
1092config HIGHMEM64G
1093 bool "64GB"
1094 depends on !M386 && !M486
1095 select X86_PAE
1096 ---help---
1097 Select this if you have a 32-bit processor and more than 4
1098 gigabytes of physical RAM.
1099
1100endchoice
1101
1102choice
1103 depends on EXPERIMENTAL
1104 prompt "Memory split" if EXPERT
1105 default VMSPLIT_3G
1106 depends on X86_32
1107 ---help---
1108 Select the desired split between kernel and user memory.
1109
1110 If the address range available to the kernel is less than the
1111 physical memory installed, the remaining memory will be available
1112 as "high memory". Accessing high memory is a little more costly
1113 than low memory, as it needs to be mapped into the kernel first.
1114 Note that increasing the kernel address space limits the range
1115 available to user programs, making the address space there
1116 tighter. Selecting anything other than the default 3G/1G split
1117 will also likely make your kernel incompatible with binary-only
1118 kernel modules.
1119
1120 If you are not absolutely sure what you are doing, leave this
1121 option alone!
1122
1123 config VMSPLIT_3G
1124 bool "3G/1G user/kernel split"
1125 config VMSPLIT_3G_OPT
1126 depends on !X86_PAE
1127 bool "3G/1G user/kernel split (for full 1G low memory)"
1128 config VMSPLIT_2G
1129 bool "2G/2G user/kernel split"
1130 config VMSPLIT_2G_OPT
1131 depends on !X86_PAE
1132 bool "2G/2G user/kernel split (for full 2G low memory)"
1133 config VMSPLIT_1G
1134 bool "1G/3G user/kernel split"
1135endchoice
1136
1137config PAGE_OFFSET
1138 hex
1139 default 0xB0000000 if VMSPLIT_3G_OPT
1140 default 0x80000000 if VMSPLIT_2G
1141 default 0x78000000 if VMSPLIT_2G_OPT
1142 default 0x40000000 if VMSPLIT_1G
1143 default 0xC0000000
1144 depends on X86_32
1145
1146config HIGHMEM
1147 def_bool y
1148 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1149
1150config X86_PAE
1151 bool "PAE (Physical Address Extension) Support"
1152 depends on X86_32 && !HIGHMEM4G
1153 ---help---
1154 PAE is required for NX support, and furthermore enables
1155 larger swapspace support for non-overcommit purposes. It
1156 has the cost of more pagetable lookup overhead, and also
1157 consumes more pagetable space per process.
1158
1159config ARCH_PHYS_ADDR_T_64BIT
1160 def_bool X86_64 || X86_PAE
1161
1162config ARCH_DMA_ADDR_T_64BIT
1163 def_bool X86_64 || HIGHMEM64G
1164
1165config DIRECT_GBPAGES
1166 bool "Enable 1GB pages for kernel pagetables" if EXPERT
1167 default y
1168 depends on X86_64
1169 ---help---
1170 Allow the kernel linear mapping to use 1GB pages on CPUs that
1171 support it. This can improve the kernel's performance a tiny bit by
1172 reducing TLB pressure. If in doubt, say "Y".
1173
1174# Common NUMA Features
1175config NUMA
1176 bool "Numa Memory Allocation and Scheduler Support"
1177 depends on SMP
1178 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1179 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1180 ---help---
1181 Enable NUMA (Non Uniform Memory Access) support.
1182
1183 The kernel will try to allocate memory used by a CPU on the
1184 local memory controller of the CPU and add some more
1185 NUMA awareness to the kernel.
1186
1187 For 64-bit this is recommended if the system is Intel Core i7
1188 (or later), AMD Opteron, or EM64T NUMA.
1189
1190 For 32-bit this is only needed on (rare) 32-bit-only platforms
1191 that support NUMA topologies, such as NUMAQ / Summit, or if you
1192 boot a 32-bit kernel on a 64-bit NUMA platform.
1193
1194 Otherwise, you should say N.
1195
1196comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1197 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1198
1199config AMD_NUMA
1200 def_bool y
1201 prompt "Old style AMD Opteron NUMA detection"
1202 depends on X86_64 && NUMA && PCI
1203 ---help---
1204 Enable AMD NUMA node topology detection. You should say Y here if
1205 you have a multi processor AMD system. This uses an old method to
1206 read the NUMA configuration directly from the builtin Northbridge
1207 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1208 which also takes priority if both are compiled in.
1209
1210config X86_64_ACPI_NUMA
1211 def_bool y
1212 prompt "ACPI NUMA detection"
1213 depends on X86_64 && NUMA && ACPI && PCI
1214 select ACPI_NUMA
1215 ---help---
1216 Enable ACPI SRAT based node topology detection.
1217
1218# Some NUMA nodes have memory ranges that span
1219# other nodes. Even though a pfn is valid and
1220# between a node's start and end pfns, it may not
1221# reside on that node. See memmap_init_zone()
1222# for details.
1223config NODES_SPAN_OTHER_NODES
1224 def_bool y
1225 depends on X86_64_ACPI_NUMA
1226
1227config NUMA_EMU
1228 bool "NUMA emulation"
1229 depends on NUMA
1230 ---help---
1231 Enable NUMA emulation. A flat machine will be split
1232 into virtual nodes when booted with "numa=fake=N", where N is the
1233 number of nodes. This is only useful for debugging.
1234
1235config NODES_SHIFT
1236 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1237 range 1 10
1238 default "10" if MAXSMP
1239 default "6" if X86_64
1240 default "4" if X86_NUMAQ
1241 default "3"
1242 depends on NEED_MULTIPLE_NODES
1243 ---help---
1244 Specify the maximum number of NUMA Nodes available on the target
1245 system. Increases memory reserved to accommodate various tables.
1246
1247config HAVE_ARCH_ALLOC_REMAP
1248 def_bool y
1249 depends on X86_32 && NUMA
1250
1251config ARCH_HAVE_MEMORY_PRESENT
1252 def_bool y
1253 depends on X86_32 && DISCONTIGMEM
1254
1255config NEED_NODE_MEMMAP_SIZE
1256 def_bool y
1257 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1258
1259config ARCH_FLATMEM_ENABLE
1260 def_bool y
1261 depends on X86_32 && !NUMA
1262
1263config ARCH_DISCONTIGMEM_ENABLE
1264 def_bool y
1265 depends on NUMA && X86_32
1266
1267config ARCH_DISCONTIGMEM_DEFAULT
1268 def_bool y
1269 depends on NUMA && X86_32
1270
1271config ARCH_SPARSEMEM_ENABLE
1272 def_bool y
1273 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1274 select SPARSEMEM_STATIC if X86_32
1275 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1276
1277config ARCH_SPARSEMEM_DEFAULT
1278 def_bool y
1279 depends on X86_64
1280
1281config ARCH_SELECT_MEMORY_MODEL
1282 def_bool y
1283 depends on ARCH_SPARSEMEM_ENABLE
1284
1285config ARCH_MEMORY_PROBE
1286 def_bool X86_64
1287 depends on MEMORY_HOTPLUG
1288
1289config ARCH_PROC_KCORE_TEXT
1290 def_bool y
1291 depends on X86_64 && PROC_KCORE
1292
1293config ILLEGAL_POINTER_VALUE
1294 hex
1295 default 0 if X86_32
1296 default 0xdead000000000000 if X86_64
1297
1298source "mm/Kconfig"
1299
1300config HIGHPTE
1301 bool "Allocate 3rd-level pagetables from highmem"
1302 depends on HIGHMEM
1303 ---help---
1304 The VM uses one page table entry for each page of physical memory.
1305 For systems with a lot of RAM, this can be wasteful of precious
1306 low memory. Setting this option will put user-space page table
1307 entries in high memory.
1308
1309config X86_CHECK_BIOS_CORRUPTION
1310 bool "Check for low memory corruption"
1311 ---help---
1312 Periodically check for memory corruption in low memory, which
1313 is suspected to be caused by BIOS. Even when enabled in the
1314 configuration, it is disabled at runtime. Enable it by
1315 setting "memory_corruption_check=1" on the kernel command
1316 line. By default it scans the low 64k of memory every 60
1317 seconds; see the memory_corruption_check_size and
1318 memory_corruption_check_period parameters in
1319 Documentation/kernel-parameters.txt to adjust this.
1320
1321 When enabled with the default parameters, this option has
1322 almost no overhead, as it reserves a relatively small amount
1323 of memory and scans it infrequently. It both detects corruption
1324 and prevents it from affecting the running system.
1325
1326 It is, however, intended as a diagnostic tool; if repeatable
1327 BIOS-originated corruption always affects the same memory,
1328 you can use memmap= to prevent the kernel from using that
1329 memory.
1330
1331config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1332 bool "Set the default setting of memory_corruption_check"
1333 depends on X86_CHECK_BIOS_CORRUPTION
1334 default y
1335 ---help---
1336 Set whether the default state of memory_corruption_check is
1337 on or off.
1338
1339config X86_RESERVE_LOW
1340 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1341 default 64
1342 range 4 640
1343 ---help---
1344 Specify the amount of low memory to reserve for the BIOS.
1345
1346 The first page contains BIOS data structures that the kernel
1347 must not use, so that page must always be reserved.
1348
1349 By default we reserve the first 64K of physical RAM, as a
1350 number of BIOSes are known to corrupt that memory range
1351 during events such as suspend/resume or monitor cable
1352 insertion, so it must not be used by the kernel.
1353
1354 You can set this to 4 if you are absolutely sure that you
1355 trust the BIOS to get all its memory reservations and usages
1356 right. If you know your BIOS have problems beyond the
1357 default 64K area, you can set this to 640 to avoid using the
1358 entire low memory range.
1359
1360 If you have doubts about the BIOS (e.g. suspend/resume does
1361 not work or there's kernel crashes after certain hardware
1362 hotplug events) then you might want to enable
1363 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1364 typical corruption patterns.
1365
1366 Leave this to the default value of 64 if you are unsure.
1367
1368config MATH_EMULATION
1369 bool
1370 prompt "Math emulation" if X86_32
1371 ---help---
1372 Linux can emulate a math coprocessor (used for floating point
1373 operations) if you don't have one. 486DX and Pentium processors have
1374 a math coprocessor built in, 486SX and 386 do not, unless you added
1375 a 487DX or 387, respectively. (The messages during boot time can
1376 give you some hints here ["man dmesg"].) Everyone needs either a
1377 coprocessor or this emulation.
1378
1379 If you don't have a math coprocessor, you need to say Y here; if you
1380 say Y here even though you have a coprocessor, the coprocessor will
1381 be used nevertheless. (This behavior can be changed with the kernel
1382 command line option "no387", which comes handy if your coprocessor
1383 is broken. Try "man bootparam" or see the documentation of your boot
1384 loader (lilo or loadlin) about how to pass options to the kernel at
1385 boot time.) This means that it is a good idea to say Y here if you
1386 intend to use this kernel on different machines.
1387
1388 More information about the internals of the Linux math coprocessor
1389 emulation can be found in <file:arch/x86/math-emu/README>.
1390
1391 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1392 kernel, it won't hurt.
1393
1394config MTRR
1395 def_bool y
1396 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1397 ---help---
1398 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1399 the Memory Type Range Registers (MTRRs) may be used to control
1400 processor access to memory ranges. This is most useful if you have
1401 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1402 allows bus write transfers to be combined into a larger transfer
1403 before bursting over the PCI/AGP bus. This can increase performance
1404 of image write operations 2.5 times or more. Saying Y here creates a
1405 /proc/mtrr file which may be used to manipulate your processor's
1406 MTRRs. Typically the X server should use this.
1407
1408 This code has a reasonably generic interface so that similar
1409 control registers on other processors can be easily supported
1410 as well:
1411
1412 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1413 Registers (ARRs) which provide a similar functionality to MTRRs. For
1414 these, the ARRs are used to emulate the MTRRs.
1415 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1416 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1417 write-combining. All of these processors are supported by this code
1418 and it makes sense to say Y here if you have one of them.
1419
1420 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1421 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1422 can lead to all sorts of problems, so it's good to say Y here.
1423
1424 You can safely say Y even if your machine doesn't have MTRRs, you'll
1425 just add about 9 KB to your kernel.
1426
1427 See <file:Documentation/x86/mtrr.txt> for more information.
1428
1429config MTRR_SANITIZER
1430 def_bool y
1431 prompt "MTRR cleanup support"
1432 depends on MTRR
1433 ---help---
1434 Convert MTRR layout from continuous to discrete, so X drivers can
1435 add writeback entries.
1436
1437 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1438 The largest mtrr entry size for a continuous block can be set with
1439 mtrr_chunk_size.
1440
1441 If unsure, say Y.
1442
1443config MTRR_SANITIZER_ENABLE_DEFAULT
1444 int "MTRR cleanup enable value (0-1)"
1445 range 0 1
1446 default "0"
1447 depends on MTRR_SANITIZER
1448 ---help---
1449 Enable mtrr cleanup default value
1450
1451config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1452 int "MTRR cleanup spare reg num (0-7)"
1453 range 0 7
1454 default "1"
1455 depends on MTRR_SANITIZER
1456 ---help---
1457 mtrr cleanup spare entries default, it can be changed via
1458 mtrr_spare_reg_nr=N on the kernel command line.
1459
1460config X86_PAT
1461 def_bool y
1462 prompt "x86 PAT support" if EXPERT
1463 depends on MTRR
1464 ---help---
1465 Use PAT attributes to setup page level cache control.
1466
1467 PATs are the modern equivalents of MTRRs and are much more
1468 flexible than MTRRs.
1469
1470 Say N here if you see bootup problems (boot crash, boot hang,
1471 spontaneous reboots) or a non-working video driver.
1472
1473 If unsure, say Y.
1474
1475config ARCH_USES_PG_UNCACHED
1476 def_bool y
1477 depends on X86_PAT
1478
1479config ARCH_RANDOM
1480 def_bool y
1481 prompt "x86 architectural random number generator" if EXPERT
1482 ---help---
1483 Enable the x86 architectural RDRAND instruction
1484 (Intel Bull Mountain technology) to generate random numbers.
1485 If supported, this is a high bandwidth, cryptographically
1486 secure hardware random number generator.
1487
1488config EFI
1489 bool "EFI runtime service support"
1490 depends on ACPI
1491 ---help---
1492 This enables the kernel to use EFI runtime services that are
1493 available (such as the EFI variable services).
1494
1495 This option is only useful on systems that have EFI firmware.
1496 In addition, you should use the latest ELILO loader available
1497 at <http://elilo.sourceforge.net> in order to take advantage
1498 of EFI runtime services. However, even with this option, the
1499 resultant kernel should continue to boot on existing non-EFI
1500 platforms.
1501
1502config EFI_STUB
1503 bool "EFI stub support"
1504 depends on EFI
1505 ---help---
1506 This kernel feature allows a bzImage to be loaded directly
1507 by EFI firmware without the use of a bootloader.
1508
1509 See Documentation/x86/efi-stub.txt for more information.
1510
1511config SECCOMP
1512 def_bool y
1513 prompt "Enable seccomp to safely compute untrusted bytecode"
1514 ---help---
1515 This kernel feature is useful for number crunching applications
1516 that may need to compute untrusted bytecode during their
1517 execution. By using pipes or other transports made available to
1518 the process as file descriptors supporting the read/write
1519 syscalls, it's possible to isolate those applications in
1520 their own address space using seccomp. Once seccomp is
1521 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1522 and the task is only allowed to execute a few safe syscalls
1523 defined by each seccomp mode.
1524
1525 If unsure, say Y. Only embedded should say N here.
1526
1527config CC_STACKPROTECTOR
1528 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1529 ---help---
1530 This option turns on the -fstack-protector GCC feature. This
1531 feature puts, at the beginning of functions, a canary value on
1532 the stack just before the return address, and validates
1533 the value just before actually returning. Stack based buffer
1534 overflows (that need to overwrite this return address) now also
1535 overwrite the canary, which gets detected and the attack is then
1536 neutralized via a kernel panic.
1537
1538 This feature requires gcc version 4.2 or above, or a distribution
1539 gcc with the feature backported. Older versions are automatically
1540 detected and for those versions, this configuration option is
1541 ignored. (and a warning is printed during bootup)
1542
1543source kernel/Kconfig.hz
1544
1545config KEXEC
1546 bool "kexec system call"
1547 ---help---
1548 kexec is a system call that implements the ability to shutdown your
1549 current kernel, and to start another kernel. It is like a reboot
1550 but it is independent of the system firmware. And like a reboot
1551 you can start any kernel with it, not just Linux.
1552
1553 The name comes from the similarity to the exec system call.
1554
1555 It is an ongoing process to be certain the hardware in a machine
1556 is properly shutdown, so do not be surprised if this code does not
1557 initially work for you. It may help to enable device hotplugging
1558 support. As of this writing the exact hardware interface is
1559 strongly in flux, so no good recommendation can be made.
1560
1561config CRASH_DUMP
1562 bool "kernel crash dumps"
1563 depends on X86_64 || (X86_32 && HIGHMEM)
1564 ---help---
1565 Generate crash dump after being started by kexec.
1566 This should be normally only set in special crash dump kernels
1567 which are loaded in the main kernel with kexec-tools into
1568 a specially reserved region and then later executed after
1569 a crash by kdump/kexec. The crash dump kernel must be compiled
1570 to a memory address not used by the main kernel or BIOS using
1571 PHYSICAL_START, or it must be built as a relocatable image
1572 (CONFIG_RELOCATABLE=y).
1573 For more details see Documentation/kdump/kdump.txt
1574
1575config KEXEC_JUMP
1576 bool "kexec jump (EXPERIMENTAL)"
1577 depends on EXPERIMENTAL
1578 depends on KEXEC && HIBERNATION
1579 ---help---
1580 Jump between original kernel and kexeced kernel and invoke
1581 code in physical address mode via KEXEC
1582
1583config PHYSICAL_START
1584 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1585 default "0x1000000"
1586 ---help---
1587 This gives the physical address where the kernel is loaded.
1588
1589 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1590 bzImage will decompress itself to above physical address and
1591 run from there. Otherwise, bzImage will run from the address where
1592 it has been loaded by the boot loader and will ignore above physical
1593 address.
1594
1595 In normal kdump cases one does not have to set/change this option
1596 as now bzImage can be compiled as a completely relocatable image
1597 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1598 address. This option is mainly useful for the folks who don't want
1599 to use a bzImage for capturing the crash dump and want to use a
1600 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1601 to be specifically compiled to run from a specific memory area
1602 (normally a reserved region) and this option comes handy.
1603
1604 So if you are using bzImage for capturing the crash dump,
1605 leave the value here unchanged to 0x1000000 and set
1606 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1607 for capturing the crash dump change this value to start of
1608 the reserved region. In other words, it can be set based on
1609 the "X" value as specified in the "crashkernel=YM@XM"
1610 command line boot parameter passed to the panic-ed
1611 kernel. Please take a look at Documentation/kdump/kdump.txt
1612 for more details about crash dumps.
1613
1614 Usage of bzImage for capturing the crash dump is recommended as
1615 one does not have to build two kernels. Same kernel can be used
1616 as production kernel and capture kernel. Above option should have
1617 gone away after relocatable bzImage support is introduced. But it
1618 is present because there are users out there who continue to use
1619 vmlinux for dump capture. This option should go away down the
1620 line.
1621
1622 Don't change this unless you know what you are doing.
1623
1624config RELOCATABLE
1625 bool "Build a relocatable kernel"
1626 default y
1627 ---help---
1628 This builds a kernel image that retains relocation information
1629 so it can be loaded someplace besides the default 1MB.
1630 The relocations tend to make the kernel binary about 10% larger,
1631 but are discarded at runtime.
1632
1633 One use is for the kexec on panic case where the recovery kernel
1634 must live at a different physical address than the primary
1635 kernel.
1636
1637 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1638 it has been loaded at and the compile time physical address
1639 (CONFIG_PHYSICAL_START) is ignored.
1640
1641# Relocation on x86-32 needs some additional build support
1642config X86_NEED_RELOCS
1643 def_bool y
1644 depends on X86_32 && RELOCATABLE
1645
1646config PHYSICAL_ALIGN
1647 hex "Alignment value to which kernel should be aligned" if X86_32
1648 default "0x1000000"
1649 range 0x2000 0x1000000
1650 ---help---
1651 This value puts the alignment restrictions on physical address
1652 where kernel is loaded and run from. Kernel is compiled for an
1653 address which meets above alignment restriction.
1654
1655 If bootloader loads the kernel at a non-aligned address and
1656 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1657 address aligned to above value and run from there.
1658
1659 If bootloader loads the kernel at a non-aligned address and
1660 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1661 load address and decompress itself to the address it has been
1662 compiled for and run from there. The address for which kernel is
1663 compiled already meets above alignment restrictions. Hence the
1664 end result is that kernel runs from a physical address meeting
1665 above alignment restrictions.
1666
1667 Don't change this unless you know what you are doing.
1668
1669config HOTPLUG_CPU
1670 bool "Support for hot-pluggable CPUs"
1671 depends on SMP && HOTPLUG
1672 ---help---
1673 Say Y here to allow turning CPUs off and on. CPUs can be
1674 controlled through /sys/devices/system/cpu.
1675 ( Note: power management support will enable this option
1676 automatically on SMP systems. )
1677 Say N if you want to disable CPU hotplug.
1678
1679config COMPAT_VDSO
1680 def_bool y
1681 prompt "Compat VDSO support"
1682 depends on X86_32 || IA32_EMULATION
1683 ---help---
1684 Map the 32-bit VDSO to the predictable old-style address too.
1685
1686 Say N here if you are running a sufficiently recent glibc
1687 version (2.3.3 or later), to remove the high-mapped
1688 VDSO mapping and to exclusively use the randomized VDSO.
1689
1690 If unsure, say Y.
1691
1692config CMDLINE_BOOL
1693 bool "Built-in kernel command line"
1694 ---help---
1695 Allow for specifying boot arguments to the kernel at
1696 build time. On some systems (e.g. embedded ones), it is
1697 necessary or convenient to provide some or all of the
1698 kernel boot arguments with the kernel itself (that is,
1699 to not rely on the boot loader to provide them.)
1700
1701 To compile command line arguments into the kernel,
1702 set this option to 'Y', then fill in the
1703 the boot arguments in CONFIG_CMDLINE.
1704
1705 Systems with fully functional boot loaders (i.e. non-embedded)
1706 should leave this option set to 'N'.
1707
1708config CMDLINE
1709 string "Built-in kernel command string"
1710 depends on CMDLINE_BOOL
1711 default ""
1712 ---help---
1713 Enter arguments here that should be compiled into the kernel
1714 image and used at boot time. If the boot loader provides a
1715 command line at boot time, it is appended to this string to
1716 form the full kernel command line, when the system boots.
1717
1718 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1719 change this behavior.
1720
1721 In most cases, the command line (whether built-in or provided
1722 by the boot loader) should specify the device for the root
1723 file system.
1724
1725config CMDLINE_OVERRIDE
1726 bool "Built-in command line overrides boot loader arguments"
1727 depends on CMDLINE_BOOL
1728 ---help---
1729 Set this option to 'Y' to have the kernel ignore the boot loader
1730 command line, and use ONLY the built-in command line.
1731
1732 This is used to work around broken boot loaders. This should
1733 be set to 'N' under normal conditions.
1734
1735endmenu
1736
1737config ARCH_ENABLE_MEMORY_HOTPLUG
1738 def_bool y
1739 depends on X86_64 || (X86_32 && HIGHMEM)
1740
1741config ARCH_ENABLE_MEMORY_HOTREMOVE
1742 def_bool y
1743 depends on MEMORY_HOTPLUG
1744
1745config USE_PERCPU_NUMA_NODE_ID
1746 def_bool y
1747 depends on NUMA
1748
1749menu "Power management and ACPI options"
1750
1751config ARCH_HIBERNATION_HEADER
1752 def_bool y
1753 depends on X86_64 && HIBERNATION
1754
1755source "kernel/power/Kconfig"
1756
1757source "drivers/acpi/Kconfig"
1758
1759source "drivers/sfi/Kconfig"
1760
1761config X86_APM_BOOT
1762 def_bool y
1763 depends on APM
1764
1765menuconfig APM
1766 tristate "APM (Advanced Power Management) BIOS support"
1767 depends on X86_32 && PM_SLEEP
1768 ---help---
1769 APM is a BIOS specification for saving power using several different
1770 techniques. This is mostly useful for battery powered laptops with
1771 APM compliant BIOSes. If you say Y here, the system time will be
1772 reset after a RESUME operation, the /proc/apm device will provide
1773 battery status information, and user-space programs will receive
1774 notification of APM "events" (e.g. battery status change).
1775
1776 If you select "Y" here, you can disable actual use of the APM
1777 BIOS by passing the "apm=off" option to the kernel at boot time.
1778
1779 Note that the APM support is almost completely disabled for
1780 machines with more than one CPU.
1781
1782 In order to use APM, you will need supporting software. For location
1783 and more information, read <file:Documentation/power/apm-acpi.txt>
1784 and the Battery Powered Linux mini-HOWTO, available from
1785 <http://www.tldp.org/docs.html#howto>.
1786
1787 This driver does not spin down disk drives (see the hdparm(8)
1788 manpage ("man 8 hdparm") for that), and it doesn't turn off
1789 VESA-compliant "green" monitors.
1790
1791 This driver does not support the TI 4000M TravelMate and the ACER
1792 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1793 desktop machines also don't have compliant BIOSes, and this driver
1794 may cause those machines to panic during the boot phase.
1795
1796 Generally, if you don't have a battery in your machine, there isn't
1797 much point in using this driver and you should say N. If you get
1798 random kernel OOPSes or reboots that don't seem to be related to
1799 anything, try disabling/enabling this option (or disabling/enabling
1800 APM in your BIOS).
1801
1802 Some other things you should try when experiencing seemingly random,
1803 "weird" problems:
1804
1805 1) make sure that you have enough swap space and that it is
1806 enabled.
1807 2) pass the "no-hlt" option to the kernel
1808 3) switch on floating point emulation in the kernel and pass
1809 the "no387" option to the kernel
1810 4) pass the "floppy=nodma" option to the kernel
1811 5) pass the "mem=4M" option to the kernel (thereby disabling
1812 all but the first 4 MB of RAM)
1813 6) make sure that the CPU is not over clocked.
1814 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1815 8) disable the cache from your BIOS settings
1816 9) install a fan for the video card or exchange video RAM
1817 10) install a better fan for the CPU
1818 11) exchange RAM chips
1819 12) exchange the motherboard.
1820
1821 To compile this driver as a module, choose M here: the
1822 module will be called apm.
1823
1824if APM
1825
1826config APM_IGNORE_USER_SUSPEND
1827 bool "Ignore USER SUSPEND"
1828 ---help---
1829 This option will ignore USER SUSPEND requests. On machines with a
1830 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1831 series notebooks, it is necessary to say Y because of a BIOS bug.
1832
1833config APM_DO_ENABLE
1834 bool "Enable PM at boot time"
1835 ---help---
1836 Enable APM features at boot time. From page 36 of the APM BIOS
1837 specification: "When disabled, the APM BIOS does not automatically
1838 power manage devices, enter the Standby State, enter the Suspend
1839 State, or take power saving steps in response to CPU Idle calls."
1840 This driver will make CPU Idle calls when Linux is idle (unless this
1841 feature is turned off -- see "Do CPU IDLE calls", below). This
1842 should always save battery power, but more complicated APM features
1843 will be dependent on your BIOS implementation. You may need to turn
1844 this option off if your computer hangs at boot time when using APM
1845 support, or if it beeps continuously instead of suspending. Turn
1846 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1847 T400CDT. This is off by default since most machines do fine without
1848 this feature.
1849
1850config APM_CPU_IDLE
1851 bool "Make CPU Idle calls when idle"
1852 ---help---
1853 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1854 On some machines, this can activate improved power savings, such as
1855 a slowed CPU clock rate, when the machine is idle. These idle calls
1856 are made after the idle loop has run for some length of time (e.g.,
1857 333 mS). On some machines, this will cause a hang at boot time or
1858 whenever the CPU becomes idle. (On machines with more than one CPU,
1859 this option does nothing.)
1860
1861config APM_DISPLAY_BLANK
1862 bool "Enable console blanking using APM"
1863 ---help---
1864 Enable console blanking using the APM. Some laptops can use this to
1865 turn off the LCD backlight when the screen blanker of the Linux
1866 virtual console blanks the screen. Note that this is only used by
1867 the virtual console screen blanker, and won't turn off the backlight
1868 when using the X Window system. This also doesn't have anything to
1869 do with your VESA-compliant power-saving monitor. Further, this
1870 option doesn't work for all laptops -- it might not turn off your
1871 backlight at all, or it might print a lot of errors to the console,
1872 especially if you are using gpm.
1873
1874config APM_ALLOW_INTS
1875 bool "Allow interrupts during APM BIOS calls"
1876 ---help---
1877 Normally we disable external interrupts while we are making calls to
1878 the APM BIOS as a measure to lessen the effects of a badly behaving
1879 BIOS implementation. The BIOS should reenable interrupts if it
1880 needs to. Unfortunately, some BIOSes do not -- especially those in
1881 many of the newer IBM Thinkpads. If you experience hangs when you
1882 suspend, try setting this to Y. Otherwise, say N.
1883
1884endif # APM
1885
1886source "drivers/cpufreq/Kconfig"
1887
1888source "drivers/cpuidle/Kconfig"
1889
1890source "drivers/idle/Kconfig"
1891
1892endmenu
1893
1894
1895menu "Bus options (PCI etc.)"
1896
1897config PCI
1898 bool "PCI support"
1899 default y
1900 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1901 ---help---
1902 Find out whether you have a PCI motherboard. PCI is the name of a
1903 bus system, i.e. the way the CPU talks to the other stuff inside
1904 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1905 VESA. If you have PCI, say Y, otherwise N.
1906
1907choice
1908 prompt "PCI access mode"
1909 depends on X86_32 && PCI
1910 default PCI_GOANY
1911 ---help---
1912 On PCI systems, the BIOS can be used to detect the PCI devices and
1913 determine their configuration. However, some old PCI motherboards
1914 have BIOS bugs and may crash if this is done. Also, some embedded
1915 PCI-based systems don't have any BIOS at all. Linux can also try to
1916 detect the PCI hardware directly without using the BIOS.
1917
1918 With this option, you can specify how Linux should detect the
1919 PCI devices. If you choose "BIOS", the BIOS will be used,
1920 if you choose "Direct", the BIOS won't be used, and if you
1921 choose "MMConfig", then PCI Express MMCONFIG will be used.
1922 If you choose "Any", the kernel will try MMCONFIG, then the
1923 direct access method and falls back to the BIOS if that doesn't
1924 work. If unsure, go with the default, which is "Any".
1925
1926config PCI_GOBIOS
1927 bool "BIOS"
1928
1929config PCI_GOMMCONFIG
1930 bool "MMConfig"
1931
1932config PCI_GODIRECT
1933 bool "Direct"
1934
1935config PCI_GOOLPC
1936 bool "OLPC XO-1"
1937 depends on OLPC
1938
1939config PCI_GOANY
1940 bool "Any"
1941
1942endchoice
1943
1944config PCI_BIOS
1945 def_bool y
1946 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1947
1948# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1949config PCI_DIRECT
1950 def_bool y
1951 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
1952
1953config PCI_MMCONFIG
1954 def_bool y
1955 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1956
1957config PCI_OLPC
1958 def_bool y
1959 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1960
1961config PCI_XEN
1962 def_bool y
1963 depends on PCI && XEN
1964 select SWIOTLB_XEN
1965
1966config PCI_DOMAINS
1967 def_bool y
1968 depends on PCI
1969
1970config PCI_MMCONFIG
1971 bool "Support mmconfig PCI config space access"
1972 depends on X86_64 && PCI && ACPI
1973
1974config PCI_CNB20LE_QUIRK
1975 bool "Read CNB20LE Host Bridge Windows" if EXPERT
1976 default n
1977 depends on PCI && EXPERIMENTAL
1978 help
1979 Read the PCI windows out of the CNB20LE host bridge. This allows
1980 PCI hotplug to work on systems with the CNB20LE chipset which do
1981 not have ACPI.
1982
1983 There's no public spec for this chipset, and this functionality
1984 is known to be incomplete.
1985
1986 You should say N unless you know you need this.
1987
1988source "drivers/pci/pcie/Kconfig"
1989
1990source "drivers/pci/Kconfig"
1991
1992# x86_64 have no ISA slots, but can have ISA-style DMA.
1993config ISA_DMA_API
1994 bool "ISA-style DMA support" if (X86_64 && EXPERT)
1995 default y
1996 help
1997 Enables ISA-style DMA support for devices requiring such controllers.
1998 If unsure, say Y.
1999
2000if X86_32
2001
2002config ISA
2003 bool "ISA support"
2004 ---help---
2005 Find out whether you have ISA slots on your motherboard. ISA is the
2006 name of a bus system, i.e. the way the CPU talks to the other stuff
2007 inside your box. Other bus systems are PCI, EISA, MicroChannel
2008 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2009 newer boards don't support it. If you have ISA, say Y, otherwise N.
2010
2011config EISA
2012 bool "EISA support"
2013 depends on ISA
2014 ---help---
2015 The Extended Industry Standard Architecture (EISA) bus was
2016 developed as an open alternative to the IBM MicroChannel bus.
2017
2018 The EISA bus provided some of the features of the IBM MicroChannel
2019 bus while maintaining backward compatibility with cards made for
2020 the older ISA bus. The EISA bus saw limited use between 1988 and
2021 1995 when it was made obsolete by the PCI bus.
2022
2023 Say Y here if you are building a kernel for an EISA-based machine.
2024
2025 Otherwise, say N.
2026
2027source "drivers/eisa/Kconfig"
2028
2029config SCx200
2030 tristate "NatSemi SCx200 support"
2031 ---help---
2032 This provides basic support for National Semiconductor's
2033 (now AMD's) Geode processors. The driver probes for the
2034 PCI-IDs of several on-chip devices, so its a good dependency
2035 for other scx200_* drivers.
2036
2037 If compiled as a module, the driver is named scx200.
2038
2039config SCx200HR_TIMER
2040 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2041 depends on SCx200
2042 default y
2043 ---help---
2044 This driver provides a clocksource built upon the on-chip
2045 27MHz high-resolution timer. Its also a workaround for
2046 NSC Geode SC-1100's buggy TSC, which loses time when the
2047 processor goes idle (as is done by the scheduler). The
2048 other workaround is idle=poll boot option.
2049
2050config OLPC
2051 bool "One Laptop Per Child support"
2052 depends on !X86_PAE
2053 select GPIOLIB
2054 select OF
2055 select OF_PROMTREE
2056 select IRQ_DOMAIN
2057 ---help---
2058 Add support for detecting the unique features of the OLPC
2059 XO hardware.
2060
2061config OLPC_XO1_PM
2062 bool "OLPC XO-1 Power Management"
2063 depends on OLPC && MFD_CS5535 && PM_SLEEP
2064 select MFD_CORE
2065 ---help---
2066 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2067
2068config OLPC_XO1_RTC
2069 bool "OLPC XO-1 Real Time Clock"
2070 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2071 ---help---
2072 Add support for the XO-1 real time clock, which can be used as a
2073 programmable wakeup source.
2074
2075config OLPC_XO1_SCI
2076 bool "OLPC XO-1 SCI extras"
2077 depends on OLPC && OLPC_XO1_PM
2078 select POWER_SUPPLY
2079 select GPIO_CS5535
2080 select MFD_CORE
2081 ---help---
2082 Add support for SCI-based features of the OLPC XO-1 laptop:
2083 - EC-driven system wakeups
2084 - Power button
2085 - Ebook switch
2086 - Lid switch
2087 - AC adapter status updates
2088 - Battery status updates
2089
2090config OLPC_XO15_SCI
2091 bool "OLPC XO-1.5 SCI extras"
2092 depends on OLPC && ACPI
2093 select POWER_SUPPLY
2094 ---help---
2095 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2096 - EC-driven system wakeups
2097 - AC adapter status updates
2098 - Battery status updates
2099
2100config ALIX
2101 bool "PCEngines ALIX System Support (LED setup)"
2102 select GPIOLIB
2103 ---help---
2104 This option enables system support for the PCEngines ALIX.
2105 At present this just sets up LEDs for GPIO control on
2106 ALIX2/3/6 boards. However, other system specific setup should
2107 get added here.
2108
2109 Note: You must still enable the drivers for GPIO and LED support
2110 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2111
2112 Note: You have to set alix.force=1 for boards with Award BIOS.
2113
2114config NET5501
2115 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2116 select GPIOLIB
2117 ---help---
2118 This option enables system support for the Soekris Engineering net5501.
2119
2120config GEOS
2121 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2122 select GPIOLIB
2123 depends on DMI
2124 ---help---
2125 This option enables system support for the Traverse Technologies GEOS.
2126
2127endif # X86_32
2128
2129config AMD_NB
2130 def_bool y
2131 depends on CPU_SUP_AMD && PCI
2132
2133source "drivers/pcmcia/Kconfig"
2134
2135source "drivers/pci/hotplug/Kconfig"
2136
2137config RAPIDIO
2138 bool "RapidIO support"
2139 depends on PCI
2140 default n
2141 help
2142 If you say Y here, the kernel will include drivers and
2143 infrastructure code to support RapidIO interconnect devices.
2144
2145source "drivers/rapidio/Kconfig"
2146
2147endmenu
2148
2149
2150menu "Executable file formats / Emulations"
2151
2152source "fs/Kconfig.binfmt"
2153
2154config IA32_EMULATION
2155 bool "IA32 Emulation"
2156 depends on X86_64
2157 select COMPAT_BINFMT_ELF
2158 ---help---
2159 Include code to run legacy 32-bit programs under a
2160 64-bit kernel. You should likely turn this on, unless you're
2161 100% sure that you don't have any 32-bit programs left.
2162
2163config IA32_AOUT
2164 tristate "IA32 a.out support"
2165 depends on IA32_EMULATION
2166 ---help---
2167 Support old a.out binaries in the 32bit emulation.
2168
2169config X86_X32
2170 bool "x32 ABI for 64-bit mode (EXPERIMENTAL)"
2171 depends on X86_64 && IA32_EMULATION && EXPERIMENTAL
2172 ---help---
2173 Include code to run binaries for the x32 native 32-bit ABI
2174 for 64-bit processors. An x32 process gets access to the
2175 full 64-bit register file and wide data path while leaving
2176 pointers at 32 bits for smaller memory footprint.
2177
2178 You will need a recent binutils (2.22 or later) with
2179 elf32_x86_64 support enabled to compile a kernel with this
2180 option set.
2181
2182config COMPAT
2183 def_bool y
2184 depends on IA32_EMULATION || X86_X32
2185 select ARCH_WANT_OLD_COMPAT_IPC
2186
2187config COMPAT_FOR_U64_ALIGNMENT
2188 def_bool COMPAT
2189 depends on X86_64
2190
2191config SYSVIPC_COMPAT
2192 def_bool y
2193 depends on COMPAT && SYSVIPC
2194
2195config KEYS_COMPAT
2196 bool
2197 depends on COMPAT && KEYS
2198 default y
2199
2200endmenu
2201
2202
2203config HAVE_ATOMIC_IOMAP
2204 def_bool y
2205 depends on X86_32
2206
2207config HAVE_TEXT_POKE_SMP
2208 bool
2209 select STOP_MACHINE if SMP
2210
2211config X86_DEV_DMA_OPS
2212 bool
2213 depends on X86_64 || STA2X11
2214
2215config X86_DMA_REMAP
2216 bool
2217 depends on STA2X11
2218
2219source "net/Kconfig"
2220
2221source "drivers/Kconfig"
2222
2223source "drivers/firmware/Kconfig"
2224
2225source "fs/Kconfig"
2226
2227source "arch/x86/Kconfig.debug"
2228
2229source "security/Kconfig"
2230
2231source "crypto/Kconfig"
2232
2233source "arch/x86/kvm/Kconfig"
2234
2235source "lib/Kconfig"
1# SPDX-License-Identifier: GPL-2.0
2# Select 32 or 64 bit
3config 64BIT
4 bool "64-bit kernel" if "$(ARCH)" = "x86"
5 default "$(ARCH)" != "i386"
6 help
7 Say yes to build a 64-bit kernel - formerly known as x86_64
8 Say no to build a 32-bit kernel - formerly known as i386
9
10config X86_32
11 def_bool y
12 depends on !64BIT
13 # Options that are inherently 32-bit kernel only:
14 select ARCH_WANT_IPC_PARSE_VERSION
15 select CLKSRC_I8253
16 select CLONE_BACKWARDS
17 select HAVE_DEBUG_STACKOVERFLOW
18 select MODULES_USE_ELF_REL
19 select OLD_SIGACTION
20 select GENERIC_VDSO_32
21
22config X86_64
23 def_bool y
24 depends on 64BIT
25 # Options that are inherently 64-bit kernel only:
26 select ARCH_HAS_GIGANTIC_PAGE
27 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
28 select ARCH_USE_CMPXCHG_LOCKREF
29 select HAVE_ARCH_SOFT_DIRTY
30 select MODULES_USE_ELF_RELA
31 select NEED_DMA_MAP_STATE
32 select SWIOTLB
33
34config FORCE_DYNAMIC_FTRACE
35 def_bool y
36 depends on X86_32
37 depends on FUNCTION_TRACER
38 select DYNAMIC_FTRACE
39 help
40 We keep the static function tracing (!DYNAMIC_FTRACE) around
41 in order to test the non static function tracing in the
42 generic code, as other architectures still use it. But we
43 only need to keep it around for x86_64. No need to keep it
44 for x86_32. For x86_32, force DYNAMIC_FTRACE.
45#
46# Arch settings
47#
48# ( Note that options that are marked 'if X86_64' could in principle be
49# ported to 32-bit as well. )
50#
51config X86
52 def_bool y
53 #
54 # Note: keep this list sorted alphabetically
55 #
56 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
57 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
58 select ARCH_32BIT_OFF_T if X86_32
59 select ARCH_CLOCKSOURCE_INIT
60 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
61 select ARCH_HAS_DEBUG_VIRTUAL
62 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE
63 select ARCH_HAS_DEVMEM_IS_ALLOWED
64 select ARCH_HAS_EARLY_DEBUG if KGDB
65 select ARCH_HAS_ELF_RANDOMIZE
66 select ARCH_HAS_FAST_MULTIPLIER
67 select ARCH_HAS_FILTER_PGPROT
68 select ARCH_HAS_FORTIFY_SOURCE
69 select ARCH_HAS_GCOV_PROFILE_ALL
70 select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION
71 select ARCH_HAS_MEM_ENCRYPT
72 select ARCH_HAS_MEMBARRIER_SYNC_CORE
73 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
74 select ARCH_HAS_PMEM_API if X86_64
75 select ARCH_HAS_PTE_DEVMAP if X86_64
76 select ARCH_HAS_PTE_SPECIAL
77 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
78 select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE
79 select ARCH_HAS_SET_MEMORY
80 select ARCH_HAS_SET_DIRECT_MAP
81 select ARCH_HAS_STRICT_KERNEL_RWX
82 select ARCH_HAS_STRICT_MODULE_RWX
83 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
84 select ARCH_HAS_SYSCALL_WRAPPER
85 select ARCH_HAS_UBSAN_SANITIZE_ALL
86 select ARCH_HAS_DEBUG_WX
87 select ARCH_HAVE_NMI_SAFE_CMPXCHG
88 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
89 select ARCH_MIGHT_HAVE_PC_PARPORT
90 select ARCH_MIGHT_HAVE_PC_SERIO
91 select ARCH_STACKWALK
92 select ARCH_SUPPORTS_ACPI
93 select ARCH_SUPPORTS_ATOMIC_RMW
94 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
95 select ARCH_USE_BUILTIN_BSWAP
96 select ARCH_USE_QUEUED_RWLOCKS
97 select ARCH_USE_QUEUED_SPINLOCKS
98 select ARCH_USE_SYM_ANNOTATIONS
99 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
100 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64
101 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
102 select ARCH_WANT_HUGE_PMD_SHARE
103 select ARCH_WANTS_THP_SWAP if X86_64
104 select BUILDTIME_TABLE_SORT
105 select CLKEVT_I8253
106 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
107 select CLOCKSOURCE_WATCHDOG
108 select DCACHE_WORD_ACCESS
109 select EDAC_ATOMIC_SCRUB
110 select EDAC_SUPPORT
111 select GENERIC_CLOCKEVENTS
112 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
113 select GENERIC_CLOCKEVENTS_MIN_ADJUST
114 select GENERIC_CMOS_UPDATE
115 select GENERIC_CPU_AUTOPROBE
116 select GENERIC_CPU_VULNERABILITIES
117 select GENERIC_EARLY_IOREMAP
118 select GENERIC_ENTRY
119 select GENERIC_FIND_FIRST_BIT
120 select GENERIC_IOMAP
121 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
122 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
123 select GENERIC_IRQ_MIGRATION if SMP
124 select GENERIC_IRQ_PROBE
125 select GENERIC_IRQ_RESERVATION_MODE
126 select GENERIC_IRQ_SHOW
127 select GENERIC_PENDING_IRQ if SMP
128 select GENERIC_PTDUMP
129 select GENERIC_SMP_IDLE_THREAD
130 select GENERIC_STRNCPY_FROM_USER
131 select GENERIC_STRNLEN_USER
132 select GENERIC_TIME_VSYSCALL
133 select GENERIC_GETTIMEOFDAY
134 select GENERIC_VDSO_TIME_NS
135 select GUP_GET_PTE_LOW_HIGH if X86_PAE
136 select HARDIRQS_SW_RESEND
137 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
138 select HAVE_ACPI_APEI if ACPI
139 select HAVE_ACPI_APEI_NMI if ACPI
140 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
141 select HAVE_ARCH_AUDITSYSCALL
142 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
143 select HAVE_ARCH_JUMP_LABEL
144 select HAVE_ARCH_JUMP_LABEL_RELATIVE
145 select HAVE_ARCH_KASAN if X86_64
146 select HAVE_ARCH_KASAN_VMALLOC if X86_64
147 select HAVE_ARCH_KGDB
148 select HAVE_ARCH_MMAP_RND_BITS if MMU
149 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
150 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
151 select HAVE_ARCH_PREL32_RELOCATIONS
152 select HAVE_ARCH_SECCOMP_FILTER
153 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
154 select HAVE_ARCH_STACKLEAK
155 select HAVE_ARCH_TRACEHOOK
156 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
157 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
158 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD
159 select HAVE_ARCH_VMAP_STACK if X86_64
160 select HAVE_ARCH_WITHIN_STACK_FRAMES
161 select HAVE_ASM_MODVERSIONS
162 select HAVE_CMPXCHG_DOUBLE
163 select HAVE_CMPXCHG_LOCAL
164 select HAVE_CONTEXT_TRACKING if X86_64
165 select HAVE_C_RECORDMCOUNT
166 select HAVE_DEBUG_KMEMLEAK
167 select HAVE_DMA_CONTIGUOUS
168 select HAVE_DYNAMIC_FTRACE
169 select HAVE_DYNAMIC_FTRACE_WITH_REGS
170 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
171 select HAVE_EBPF_JIT
172 select HAVE_EFFICIENT_UNALIGNED_ACCESS
173 select HAVE_EISA
174 select HAVE_EXIT_THREAD
175 select HAVE_FAST_GUP
176 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
177 select HAVE_FTRACE_MCOUNT_RECORD
178 select HAVE_FUNCTION_GRAPH_TRACER
179 select HAVE_FUNCTION_TRACER
180 select HAVE_GCC_PLUGINS
181 select HAVE_HW_BREAKPOINT
182 select HAVE_IDE
183 select HAVE_IOREMAP_PROT
184 select HAVE_IRQ_TIME_ACCOUNTING
185 select HAVE_KERNEL_BZIP2
186 select HAVE_KERNEL_GZIP
187 select HAVE_KERNEL_LZ4
188 select HAVE_KERNEL_LZMA
189 select HAVE_KERNEL_LZO
190 select HAVE_KERNEL_XZ
191 select HAVE_KERNEL_ZSTD
192 select HAVE_KPROBES
193 select HAVE_KPROBES_ON_FTRACE
194 select HAVE_FUNCTION_ERROR_INJECTION
195 select HAVE_KRETPROBES
196 select HAVE_KVM
197 select HAVE_LIVEPATCH if X86_64
198 select HAVE_MIXED_BREAKPOINTS_REGS
199 select HAVE_MOD_ARCH_SPECIFIC
200 select HAVE_MOVE_PMD
201 select HAVE_NMI
202 select HAVE_OPROFILE
203 select HAVE_OPTPROBES
204 select HAVE_PCSPKR_PLATFORM
205 select HAVE_PERF_EVENTS
206 select HAVE_PERF_EVENTS_NMI
207 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
208 select HAVE_PCI
209 select HAVE_PERF_REGS
210 select HAVE_PERF_USER_STACK_DUMP
211 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT
212 select HAVE_POSIX_CPU_TIMERS_TASK_WORK
213 select HAVE_REGS_AND_STACK_ACCESS_API
214 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
215 select HAVE_FUNCTION_ARG_ACCESS_API
216 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
217 select HAVE_STACK_VALIDATION if X86_64
218 select HAVE_RSEQ
219 select HAVE_SYSCALL_TRACEPOINTS
220 select HAVE_UNSTABLE_SCHED_CLOCK
221 select HAVE_USER_RETURN_NOTIFIER
222 select HAVE_GENERIC_VDSO
223 select HOTPLUG_SMT if SMP
224 select IRQ_FORCED_THREADING
225 select NEED_SG_DMA_LENGTH
226 select PCI_DOMAINS if PCI
227 select PCI_LOCKLESS_CONFIG if PCI
228 select PERF_EVENTS
229 select RTC_LIB
230 select RTC_MC146818_LIB
231 select SPARSE_IRQ
232 select SRCU
233 select SYSCTL_EXCEPTION_TRACE
234 select THREAD_INFO_IN_TASK
235 select USER_STACKTRACE_SUPPORT
236 select VIRT_TO_BUS
237 select HAVE_ARCH_KCSAN if X86_64
238 select X86_FEATURE_NAMES if PROC_FS
239 select PROC_PID_ARCH_STATUS if PROC_FS
240 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI
241
242config INSTRUCTION_DECODER
243 def_bool y
244 depends on KPROBES || PERF_EVENTS || UPROBES
245
246config OUTPUT_FORMAT
247 string
248 default "elf32-i386" if X86_32
249 default "elf64-x86-64" if X86_64
250
251config LOCKDEP_SUPPORT
252 def_bool y
253
254config STACKTRACE_SUPPORT
255 def_bool y
256
257config MMU
258 def_bool y
259
260config ARCH_MMAP_RND_BITS_MIN
261 default 28 if 64BIT
262 default 8
263
264config ARCH_MMAP_RND_BITS_MAX
265 default 32 if 64BIT
266 default 16
267
268config ARCH_MMAP_RND_COMPAT_BITS_MIN
269 default 8
270
271config ARCH_MMAP_RND_COMPAT_BITS_MAX
272 default 16
273
274config SBUS
275 bool
276
277config GENERIC_ISA_DMA
278 def_bool y
279 depends on ISA_DMA_API
280
281config GENERIC_BUG
282 def_bool y
283 depends on BUG
284 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
285
286config GENERIC_BUG_RELATIVE_POINTERS
287 bool
288
289config ARCH_MAY_HAVE_PC_FDC
290 def_bool y
291 depends on ISA_DMA_API
292
293config GENERIC_CALIBRATE_DELAY
294 def_bool y
295
296config ARCH_HAS_CPU_RELAX
297 def_bool y
298
299config ARCH_HAS_CACHE_LINE_SIZE
300 def_bool y
301
302config ARCH_HAS_FILTER_PGPROT
303 def_bool y
304
305config HAVE_SETUP_PER_CPU_AREA
306 def_bool y
307
308config NEED_PER_CPU_EMBED_FIRST_CHUNK
309 def_bool y
310
311config NEED_PER_CPU_PAGE_FIRST_CHUNK
312 def_bool y
313
314config ARCH_HIBERNATION_POSSIBLE
315 def_bool y
316
317config ARCH_SUSPEND_POSSIBLE
318 def_bool y
319
320config ARCH_WANT_GENERAL_HUGETLB
321 def_bool y
322
323config ZONE_DMA32
324 def_bool y if X86_64
325
326config AUDIT_ARCH
327 def_bool y if X86_64
328
329config ARCH_SUPPORTS_DEBUG_PAGEALLOC
330 def_bool y
331
332config KASAN_SHADOW_OFFSET
333 hex
334 depends on KASAN
335 default 0xdffffc0000000000
336
337config HAVE_INTEL_TXT
338 def_bool y
339 depends on INTEL_IOMMU && ACPI
340
341config X86_32_SMP
342 def_bool y
343 depends on X86_32 && SMP
344
345config X86_64_SMP
346 def_bool y
347 depends on X86_64 && SMP
348
349config X86_32_LAZY_GS
350 def_bool y
351 depends on X86_32 && !STACKPROTECTOR
352
353config ARCH_SUPPORTS_UPROBES
354 def_bool y
355
356config FIX_EARLYCON_MEM
357 def_bool y
358
359config DYNAMIC_PHYSICAL_MASK
360 bool
361
362config PGTABLE_LEVELS
363 int
364 default 5 if X86_5LEVEL
365 default 4 if X86_64
366 default 3 if X86_PAE
367 default 2
368
369config CC_HAS_SANE_STACKPROTECTOR
370 bool
371 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
372 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
373 help
374 We have to make sure stack protector is unconditionally disabled if
375 the compiler produces broken code.
376
377menu "Processor type and features"
378
379config ZONE_DMA
380 bool "DMA memory allocation support" if EXPERT
381 default y
382 help
383 DMA memory allocation support allows devices with less than 32-bit
384 addressing to allocate within the first 16MB of address space.
385 Disable if no such devices will be used.
386
387 If unsure, say Y.
388
389config SMP
390 bool "Symmetric multi-processing support"
391 help
392 This enables support for systems with more than one CPU. If you have
393 a system with only one CPU, say N. If you have a system with more
394 than one CPU, say Y.
395
396 If you say N here, the kernel will run on uni- and multiprocessor
397 machines, but will use only one CPU of a multiprocessor machine. If
398 you say Y here, the kernel will run on many, but not all,
399 uniprocessor machines. On a uniprocessor machine, the kernel
400 will run faster if you say N here.
401
402 Note that if you say Y here and choose architecture "586" or
403 "Pentium" under "Processor family", the kernel will not work on 486
404 architectures. Similarly, multiprocessor kernels for the "PPro"
405 architecture may not work on all Pentium based boards.
406
407 People using multiprocessor machines who say Y here should also say
408 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
409 Management" code will be disabled if you say Y here.
410
411 See also <file:Documentation/x86/i386/IO-APIC.rst>,
412 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
413 <http://www.tldp.org/docs.html#howto>.
414
415 If you don't know what to do here, say N.
416
417config X86_FEATURE_NAMES
418 bool "Processor feature human-readable names" if EMBEDDED
419 default y
420 help
421 This option compiles in a table of x86 feature bits and corresponding
422 names. This is required to support /proc/cpuinfo and a few kernel
423 messages. You can disable this to save space, at the expense of
424 making those few kernel messages show numeric feature bits instead.
425
426 If in doubt, say Y.
427
428config X86_X2APIC
429 bool "Support x2apic"
430 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
431 help
432 This enables x2apic support on CPUs that have this feature.
433
434 This allows 32-bit apic IDs (so it can support very large systems),
435 and accesses the local apic via MSRs not via mmio.
436
437 If you don't know what to do here, say N.
438
439config X86_MPPARSE
440 bool "Enable MPS table" if ACPI || SFI
441 default y
442 depends on X86_LOCAL_APIC
443 help
444 For old smp systems that do not have proper acpi support. Newer systems
445 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
446
447config GOLDFISH
448 def_bool y
449 depends on X86_GOLDFISH
450
451config RETPOLINE
452 bool "Avoid speculative indirect branches in kernel"
453 default y
454 select STACK_VALIDATION if HAVE_STACK_VALIDATION
455 help
456 Compile kernel with the retpoline compiler options to guard against
457 kernel-to-user data leaks by avoiding speculative indirect
458 branches. Requires a compiler with -mindirect-branch=thunk-extern
459 support for full protection. The kernel may run slower.
460
461config X86_CPU_RESCTRL
462 bool "x86 CPU resource control support"
463 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
464 select KERNFS
465 select PROC_CPU_RESCTRL if PROC_FS
466 help
467 Enable x86 CPU resource control support.
468
469 Provide support for the allocation and monitoring of system resources
470 usage by the CPU.
471
472 Intel calls this Intel Resource Director Technology
473 (Intel(R) RDT). More information about RDT can be found in the
474 Intel x86 Architecture Software Developer Manual.
475
476 AMD calls this AMD Platform Quality of Service (AMD QoS).
477 More information about AMD QoS can be found in the AMD64 Technology
478 Platform Quality of Service Extensions manual.
479
480 Say N if unsure.
481
482if X86_32
483config X86_BIGSMP
484 bool "Support for big SMP systems with more than 8 CPUs"
485 depends on SMP
486 help
487 This option is needed for the systems that have more than 8 CPUs.
488
489config X86_EXTENDED_PLATFORM
490 bool "Support for extended (non-PC) x86 platforms"
491 default y
492 help
493 If you disable this option then the kernel will only support
494 standard PC platforms. (which covers the vast majority of
495 systems out there.)
496
497 If you enable this option then you'll be able to select support
498 for the following (non-PC) 32 bit x86 platforms:
499 Goldfish (Android emulator)
500 AMD Elan
501 RDC R-321x SoC
502 SGI 320/540 (Visual Workstation)
503 STA2X11-based (e.g. Northville)
504 Moorestown MID devices
505
506 If you have one of these systems, or if you want to build a
507 generic distribution kernel, say Y here - otherwise say N.
508endif
509
510if X86_64
511config X86_EXTENDED_PLATFORM
512 bool "Support for extended (non-PC) x86 platforms"
513 default y
514 help
515 If you disable this option then the kernel will only support
516 standard PC platforms. (which covers the vast majority of
517 systems out there.)
518
519 If you enable this option then you'll be able to select support
520 for the following (non-PC) 64 bit x86 platforms:
521 Numascale NumaChip
522 ScaleMP vSMP
523 SGI Ultraviolet
524
525 If you have one of these systems, or if you want to build a
526 generic distribution kernel, say Y here - otherwise say N.
527endif
528# This is an alphabetically sorted list of 64 bit extended platforms
529# Please maintain the alphabetic order if and when there are additions
530config X86_NUMACHIP
531 bool "Numascale NumaChip"
532 depends on X86_64
533 depends on X86_EXTENDED_PLATFORM
534 depends on NUMA
535 depends on SMP
536 depends on X86_X2APIC
537 depends on PCI_MMCONFIG
538 help
539 Adds support for Numascale NumaChip large-SMP systems. Needed to
540 enable more than ~168 cores.
541 If you don't have one of these, you should say N here.
542
543config X86_VSMP
544 bool "ScaleMP vSMP"
545 select HYPERVISOR_GUEST
546 select PARAVIRT
547 depends on X86_64 && PCI
548 depends on X86_EXTENDED_PLATFORM
549 depends on SMP
550 help
551 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
552 supposed to run on these EM64T-based machines. Only choose this option
553 if you have one of these machines.
554
555config X86_UV
556 bool "SGI Ultraviolet"
557 depends on X86_64
558 depends on X86_EXTENDED_PLATFORM
559 depends on NUMA
560 depends on EFI
561 depends on X86_X2APIC
562 depends on PCI
563 help
564 This option is needed in order to support SGI Ultraviolet systems.
565 If you don't have one of these, you should say N here.
566
567# Following is an alphabetically sorted list of 32 bit extended platforms
568# Please maintain the alphabetic order if and when there are additions
569
570config X86_GOLDFISH
571 bool "Goldfish (Virtual Platform)"
572 depends on X86_EXTENDED_PLATFORM
573 help
574 Enable support for the Goldfish virtual platform used primarily
575 for Android development. Unless you are building for the Android
576 Goldfish emulator say N here.
577
578config X86_INTEL_CE
579 bool "CE4100 TV platform"
580 depends on PCI
581 depends on PCI_GODIRECT
582 depends on X86_IO_APIC
583 depends on X86_32
584 depends on X86_EXTENDED_PLATFORM
585 select X86_REBOOTFIXUPS
586 select OF
587 select OF_EARLY_FLATTREE
588 help
589 Select for the Intel CE media processor (CE4100) SOC.
590 This option compiles in support for the CE4100 SOC for settop
591 boxes and media devices.
592
593config X86_INTEL_MID
594 bool "Intel MID platform support"
595 depends on X86_EXTENDED_PLATFORM
596 depends on X86_PLATFORM_DEVICES
597 depends on PCI
598 depends on X86_64 || (PCI_GOANY && X86_32)
599 depends on X86_IO_APIC
600 select SFI
601 select I2C
602 select DW_APB_TIMER
603 select APB_TIMER
604 select INTEL_SCU_PCI
605 select MFD_INTEL_MSIC
606 help
607 Select to build a kernel capable of supporting Intel MID (Mobile
608 Internet Device) platform systems which do not have the PCI legacy
609 interfaces. If you are building for a PC class system say N here.
610
611 Intel MID platforms are based on an Intel processor and chipset which
612 consume less power than most of the x86 derivatives.
613
614config X86_INTEL_QUARK
615 bool "Intel Quark platform support"
616 depends on X86_32
617 depends on X86_EXTENDED_PLATFORM
618 depends on X86_PLATFORM_DEVICES
619 depends on X86_TSC
620 depends on PCI
621 depends on PCI_GOANY
622 depends on X86_IO_APIC
623 select IOSF_MBI
624 select INTEL_IMR
625 select COMMON_CLK
626 help
627 Select to include support for Quark X1000 SoC.
628 Say Y here if you have a Quark based system such as the Arduino
629 compatible Intel Galileo.
630
631config X86_INTEL_LPSS
632 bool "Intel Low Power Subsystem Support"
633 depends on X86 && ACPI && PCI
634 select COMMON_CLK
635 select PINCTRL
636 select IOSF_MBI
637 help
638 Select to build support for Intel Low Power Subsystem such as
639 found on Intel Lynxpoint PCH. Selecting this option enables
640 things like clock tree (common clock framework) and pincontrol
641 which are needed by the LPSS peripheral drivers.
642
643config X86_AMD_PLATFORM_DEVICE
644 bool "AMD ACPI2Platform devices support"
645 depends on ACPI
646 select COMMON_CLK
647 select PINCTRL
648 help
649 Select to interpret AMD specific ACPI device to platform device
650 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
651 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
652 implemented under PINCTRL subsystem.
653
654config IOSF_MBI
655 tristate "Intel SoC IOSF Sideband support for SoC platforms"
656 depends on PCI
657 help
658 This option enables sideband register access support for Intel SoC
659 platforms. On these platforms the IOSF sideband is used in lieu of
660 MSR's for some register accesses, mostly but not limited to thermal
661 and power. Drivers may query the availability of this device to
662 determine if they need the sideband in order to work on these
663 platforms. The sideband is available on the following SoC products.
664 This list is not meant to be exclusive.
665 - BayTrail
666 - Braswell
667 - Quark
668
669 You should say Y if you are running a kernel on one of these SoC's.
670
671config IOSF_MBI_DEBUG
672 bool "Enable IOSF sideband access through debugfs"
673 depends on IOSF_MBI && DEBUG_FS
674 help
675 Select this option to expose the IOSF sideband access registers (MCR,
676 MDR, MCRX) through debugfs to write and read register information from
677 different units on the SoC. This is most useful for obtaining device
678 state information for debug and analysis. As this is a general access
679 mechanism, users of this option would have specific knowledge of the
680 device they want to access.
681
682 If you don't require the option or are in doubt, say N.
683
684config X86_RDC321X
685 bool "RDC R-321x SoC"
686 depends on X86_32
687 depends on X86_EXTENDED_PLATFORM
688 select M486
689 select X86_REBOOTFIXUPS
690 help
691 This option is needed for RDC R-321x system-on-chip, also known
692 as R-8610-(G).
693 If you don't have one of these chips, you should say N here.
694
695config X86_32_NON_STANDARD
696 bool "Support non-standard 32-bit SMP architectures"
697 depends on X86_32 && SMP
698 depends on X86_EXTENDED_PLATFORM
699 help
700 This option compiles in the bigsmp and STA2X11 default
701 subarchitectures. It is intended for a generic binary
702 kernel. If you select them all, kernel will probe it one by
703 one and will fallback to default.
704
705# Alphabetically sorted list of Non standard 32 bit platforms
706
707config X86_SUPPORTS_MEMORY_FAILURE
708 def_bool y
709 # MCE code calls memory_failure():
710 depends on X86_MCE
711 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
712 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
713 depends on X86_64 || !SPARSEMEM
714 select ARCH_SUPPORTS_MEMORY_FAILURE
715
716config STA2X11
717 bool "STA2X11 Companion Chip Support"
718 depends on X86_32_NON_STANDARD && PCI
719 select SWIOTLB
720 select MFD_STA2X11
721 select GPIOLIB
722 help
723 This adds support for boards based on the STA2X11 IO-Hub,
724 a.k.a. "ConneXt". The chip is used in place of the standard
725 PC chipset, so all "standard" peripherals are missing. If this
726 option is selected the kernel will still be able to boot on
727 standard PC machines.
728
729config X86_32_IRIS
730 tristate "Eurobraille/Iris poweroff module"
731 depends on X86_32
732 help
733 The Iris machines from EuroBraille do not have APM or ACPI support
734 to shut themselves down properly. A special I/O sequence is
735 needed to do so, which is what this module does at
736 kernel shutdown.
737
738 This is only for Iris machines from EuroBraille.
739
740 If unused, say N.
741
742config SCHED_OMIT_FRAME_POINTER
743 def_bool y
744 prompt "Single-depth WCHAN output"
745 depends on X86
746 help
747 Calculate simpler /proc/<PID>/wchan values. If this option
748 is disabled then wchan values will recurse back to the
749 caller function. This provides more accurate wchan values,
750 at the expense of slightly more scheduling overhead.
751
752 If in doubt, say "Y".
753
754menuconfig HYPERVISOR_GUEST
755 bool "Linux guest support"
756 help
757 Say Y here to enable options for running Linux under various hyper-
758 visors. This option enables basic hypervisor detection and platform
759 setup.
760
761 If you say N, all options in this submenu will be skipped and
762 disabled, and Linux guest support won't be built in.
763
764if HYPERVISOR_GUEST
765
766config PARAVIRT
767 bool "Enable paravirtualization code"
768 help
769 This changes the kernel so it can modify itself when it is run
770 under a hypervisor, potentially improving performance significantly
771 over full virtualization. However, when run without a hypervisor
772 the kernel is theoretically slower and slightly larger.
773
774config PARAVIRT_XXL
775 bool
776
777config PARAVIRT_DEBUG
778 bool "paravirt-ops debugging"
779 depends on PARAVIRT && DEBUG_KERNEL
780 help
781 Enable to debug paravirt_ops internals. Specifically, BUG if
782 a paravirt_op is missing when it is called.
783
784config PARAVIRT_SPINLOCKS
785 bool "Paravirtualization layer for spinlocks"
786 depends on PARAVIRT && SMP
787 help
788 Paravirtualized spinlocks allow a pvops backend to replace the
789 spinlock implementation with something virtualization-friendly
790 (for example, block the virtual CPU rather than spinning).
791
792 It has a minimal impact on native kernels and gives a nice performance
793 benefit on paravirtualized KVM / Xen kernels.
794
795 If you are unsure how to answer this question, answer Y.
796
797config X86_HV_CALLBACK_VECTOR
798 def_bool n
799
800source "arch/x86/xen/Kconfig"
801
802config KVM_GUEST
803 bool "KVM Guest support (including kvmclock)"
804 depends on PARAVIRT
805 select PARAVIRT_CLOCK
806 select ARCH_CPUIDLE_HALTPOLL
807 select X86_HV_CALLBACK_VECTOR
808 default y
809 help
810 This option enables various optimizations for running under the KVM
811 hypervisor. It includes a paravirtualized clock, so that instead
812 of relying on a PIT (or probably other) emulation by the
813 underlying device model, the host provides the guest with
814 timing infrastructure such as time of day, and system time
815
816config ARCH_CPUIDLE_HALTPOLL
817 def_bool n
818 prompt "Disable host haltpoll when loading haltpoll driver"
819 help
820 If virtualized under KVM, disable host haltpoll.
821
822config PVH
823 bool "Support for running PVH guests"
824 help
825 This option enables the PVH entry point for guest virtual machines
826 as specified in the x86/HVM direct boot ABI.
827
828config PARAVIRT_TIME_ACCOUNTING
829 bool "Paravirtual steal time accounting"
830 depends on PARAVIRT
831 help
832 Select this option to enable fine granularity task steal time
833 accounting. Time spent executing other tasks in parallel with
834 the current vCPU is discounted from the vCPU power. To account for
835 that, there can be a small performance impact.
836
837 If in doubt, say N here.
838
839config PARAVIRT_CLOCK
840 bool
841
842config JAILHOUSE_GUEST
843 bool "Jailhouse non-root cell support"
844 depends on X86_64 && PCI
845 select X86_PM_TIMER
846 help
847 This option allows to run Linux as guest in a Jailhouse non-root
848 cell. You can leave this option disabled if you only want to start
849 Jailhouse and run Linux afterwards in the root cell.
850
851config ACRN_GUEST
852 bool "ACRN Guest support"
853 depends on X86_64
854 select X86_HV_CALLBACK_VECTOR
855 help
856 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
857 a flexible, lightweight reference open-source hypervisor, built with
858 real-time and safety-criticality in mind. It is built for embedded
859 IOT with small footprint and real-time features. More details can be
860 found in https://projectacrn.org/.
861
862endif #HYPERVISOR_GUEST
863
864source "arch/x86/Kconfig.cpu"
865
866config HPET_TIMER
867 def_bool X86_64
868 prompt "HPET Timer Support" if X86_32
869 help
870 Use the IA-PC HPET (High Precision Event Timer) to manage
871 time in preference to the PIT and RTC, if a HPET is
872 present.
873 HPET is the next generation timer replacing legacy 8254s.
874 The HPET provides a stable time base on SMP
875 systems, unlike the TSC, but it is more expensive to access,
876 as it is off-chip. The interface used is documented
877 in the HPET spec, revision 1.
878
879 You can safely choose Y here. However, HPET will only be
880 activated if the platform and the BIOS support this feature.
881 Otherwise the 8254 will be used for timing services.
882
883 Choose N to continue using the legacy 8254 timer.
884
885config HPET_EMULATE_RTC
886 def_bool y
887 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
888
889config APB_TIMER
890 def_bool y if X86_INTEL_MID
891 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
892 select DW_APB_TIMER
893 depends on X86_INTEL_MID && SFI
894 help
895 APB timer is the replacement for 8254, HPET on X86 MID platforms.
896 The APBT provides a stable time base on SMP
897 systems, unlike the TSC, but it is more expensive to access,
898 as it is off-chip. APB timers are always running regardless of CPU
899 C states, they are used as per CPU clockevent device when possible.
900
901# Mark as expert because too many people got it wrong.
902# The code disables itself when not needed.
903config DMI
904 default y
905 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
906 bool "Enable DMI scanning" if EXPERT
907 help
908 Enabled scanning of DMI to identify machine quirks. Say Y
909 here unless you have verified that your setup is not
910 affected by entries in the DMI blacklist. Required by PNP
911 BIOS code.
912
913config GART_IOMMU
914 bool "Old AMD GART IOMMU support"
915 select DMA_OPS
916 select IOMMU_HELPER
917 select SWIOTLB
918 depends on X86_64 && PCI && AMD_NB
919 help
920 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
921 GART based hardware IOMMUs.
922
923 The GART supports full DMA access for devices with 32-bit access
924 limitations, on systems with more than 3 GB. This is usually needed
925 for USB, sound, many IDE/SATA chipsets and some other devices.
926
927 Newer systems typically have a modern AMD IOMMU, supported via
928 the CONFIG_AMD_IOMMU=y config option.
929
930 In normal configurations this driver is only active when needed:
931 there's more than 3 GB of memory and the system contains a
932 32-bit limited device.
933
934 If unsure, say Y.
935
936config MAXSMP
937 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
938 depends on X86_64 && SMP && DEBUG_KERNEL
939 select CPUMASK_OFFSTACK
940 help
941 Enable maximum number of CPUS and NUMA Nodes for this architecture.
942 If unsure, say N.
943
944#
945# The maximum number of CPUs supported:
946#
947# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
948# and which can be configured interactively in the
949# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
950#
951# The ranges are different on 32-bit and 64-bit kernels, depending on
952# hardware capabilities and scalability features of the kernel.
953#
954# ( If MAXSMP is enabled we just use the highest possible value and disable
955# interactive configuration. )
956#
957
958config NR_CPUS_RANGE_BEGIN
959 int
960 default NR_CPUS_RANGE_END if MAXSMP
961 default 1 if !SMP
962 default 2
963
964config NR_CPUS_RANGE_END
965 int
966 depends on X86_32
967 default 64 if SMP && X86_BIGSMP
968 default 8 if SMP && !X86_BIGSMP
969 default 1 if !SMP
970
971config NR_CPUS_RANGE_END
972 int
973 depends on X86_64
974 default 8192 if SMP && CPUMASK_OFFSTACK
975 default 512 if SMP && !CPUMASK_OFFSTACK
976 default 1 if !SMP
977
978config NR_CPUS_DEFAULT
979 int
980 depends on X86_32
981 default 32 if X86_BIGSMP
982 default 8 if SMP
983 default 1 if !SMP
984
985config NR_CPUS_DEFAULT
986 int
987 depends on X86_64
988 default 8192 if MAXSMP
989 default 64 if SMP
990 default 1 if !SMP
991
992config NR_CPUS
993 int "Maximum number of CPUs" if SMP && !MAXSMP
994 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
995 default NR_CPUS_DEFAULT
996 help
997 This allows you to specify the maximum number of CPUs which this
998 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
999 supported value is 8192, otherwise the maximum value is 512. The
1000 minimum value which makes sense is 2.
1001
1002 This is purely to save memory: each supported CPU adds about 8KB
1003 to the kernel image.
1004
1005config SCHED_SMT
1006 def_bool y if SMP
1007
1008config SCHED_MC
1009 def_bool y
1010 prompt "Multi-core scheduler support"
1011 depends on SMP
1012 help
1013 Multi-core scheduler support improves the CPU scheduler's decision
1014 making when dealing with multi-core CPU chips at a cost of slightly
1015 increased overhead in some places. If unsure say N here.
1016
1017config SCHED_MC_PRIO
1018 bool "CPU core priorities scheduler support"
1019 depends on SCHED_MC && CPU_SUP_INTEL
1020 select X86_INTEL_PSTATE
1021 select CPU_FREQ
1022 default y
1023 help
1024 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1025 core ordering determined at manufacturing time, which allows
1026 certain cores to reach higher turbo frequencies (when running
1027 single threaded workloads) than others.
1028
1029 Enabling this kernel feature teaches the scheduler about
1030 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1031 scheduler's CPU selection logic accordingly, so that higher
1032 overall system performance can be achieved.
1033
1034 This feature will have no effect on CPUs without this feature.
1035
1036 If unsure say Y here.
1037
1038config UP_LATE_INIT
1039 def_bool y
1040 depends on !SMP && X86_LOCAL_APIC
1041
1042config X86_UP_APIC
1043 bool "Local APIC support on uniprocessors" if !PCI_MSI
1044 default PCI_MSI
1045 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1046 help
1047 A local APIC (Advanced Programmable Interrupt Controller) is an
1048 integrated interrupt controller in the CPU. If you have a single-CPU
1049 system which has a processor with a local APIC, you can say Y here to
1050 enable and use it. If you say Y here even though your machine doesn't
1051 have a local APIC, then the kernel will still run with no slowdown at
1052 all. The local APIC supports CPU-generated self-interrupts (timer,
1053 performance counters), and the NMI watchdog which detects hard
1054 lockups.
1055
1056config X86_UP_IOAPIC
1057 bool "IO-APIC support on uniprocessors"
1058 depends on X86_UP_APIC
1059 help
1060 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1061 SMP-capable replacement for PC-style interrupt controllers. Most
1062 SMP systems and many recent uniprocessor systems have one.
1063
1064 If you have a single-CPU system with an IO-APIC, you can say Y here
1065 to use it. If you say Y here even though your machine doesn't have
1066 an IO-APIC, then the kernel will still run with no slowdown at all.
1067
1068config X86_LOCAL_APIC
1069 def_bool y
1070 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1071 select IRQ_DOMAIN_HIERARCHY
1072 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1073
1074config X86_IO_APIC
1075 def_bool y
1076 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1077
1078config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1079 bool "Reroute for broken boot IRQs"
1080 depends on X86_IO_APIC
1081 help
1082 This option enables a workaround that fixes a source of
1083 spurious interrupts. This is recommended when threaded
1084 interrupt handling is used on systems where the generation of
1085 superfluous "boot interrupts" cannot be disabled.
1086
1087 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1088 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1089 kernel does during interrupt handling). On chipsets where this
1090 boot IRQ generation cannot be disabled, this workaround keeps
1091 the original IRQ line masked so that only the equivalent "boot
1092 IRQ" is delivered to the CPUs. The workaround also tells the
1093 kernel to set up the IRQ handler on the boot IRQ line. In this
1094 way only one interrupt is delivered to the kernel. Otherwise
1095 the spurious second interrupt may cause the kernel to bring
1096 down (vital) interrupt lines.
1097
1098 Only affects "broken" chipsets. Interrupt sharing may be
1099 increased on these systems.
1100
1101config X86_MCE
1102 bool "Machine Check / overheating reporting"
1103 select GENERIC_ALLOCATOR
1104 default y
1105 help
1106 Machine Check support allows the processor to notify the
1107 kernel if it detects a problem (e.g. overheating, data corruption).
1108 The action the kernel takes depends on the severity of the problem,
1109 ranging from warning messages to halting the machine.
1110
1111config X86_MCELOG_LEGACY
1112 bool "Support for deprecated /dev/mcelog character device"
1113 depends on X86_MCE
1114 help
1115 Enable support for /dev/mcelog which is needed by the old mcelog
1116 userspace logging daemon. Consider switching to the new generation
1117 rasdaemon solution.
1118
1119config X86_MCE_INTEL
1120 def_bool y
1121 prompt "Intel MCE features"
1122 depends on X86_MCE && X86_LOCAL_APIC
1123 help
1124 Additional support for intel specific MCE features such as
1125 the thermal monitor.
1126
1127config X86_MCE_AMD
1128 def_bool y
1129 prompt "AMD MCE features"
1130 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1131 help
1132 Additional support for AMD specific MCE features such as
1133 the DRAM Error Threshold.
1134
1135config X86_ANCIENT_MCE
1136 bool "Support for old Pentium 5 / WinChip machine checks"
1137 depends on X86_32 && X86_MCE
1138 help
1139 Include support for machine check handling on old Pentium 5 or WinChip
1140 systems. These typically need to be enabled explicitly on the command
1141 line.
1142
1143config X86_MCE_THRESHOLD
1144 depends on X86_MCE_AMD || X86_MCE_INTEL
1145 def_bool y
1146
1147config X86_MCE_INJECT
1148 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1149 tristate "Machine check injector support"
1150 help
1151 Provide support for injecting machine checks for testing purposes.
1152 If you don't know what a machine check is and you don't do kernel
1153 QA it is safe to say n.
1154
1155config X86_THERMAL_VECTOR
1156 def_bool y
1157 depends on X86_MCE_INTEL
1158
1159source "arch/x86/events/Kconfig"
1160
1161config X86_LEGACY_VM86
1162 bool "Legacy VM86 support"
1163 depends on X86_32
1164 help
1165 This option allows user programs to put the CPU into V8086
1166 mode, which is an 80286-era approximation of 16-bit real mode.
1167
1168 Some very old versions of X and/or vbetool require this option
1169 for user mode setting. Similarly, DOSEMU will use it if
1170 available to accelerate real mode DOS programs. However, any
1171 recent version of DOSEMU, X, or vbetool should be fully
1172 functional even without kernel VM86 support, as they will all
1173 fall back to software emulation. Nevertheless, if you are using
1174 a 16-bit DOS program where 16-bit performance matters, vm86
1175 mode might be faster than emulation and you might want to
1176 enable this option.
1177
1178 Note that any app that works on a 64-bit kernel is unlikely to
1179 need this option, as 64-bit kernels don't, and can't, support
1180 V8086 mode. This option is also unrelated to 16-bit protected
1181 mode and is not needed to run most 16-bit programs under Wine.
1182
1183 Enabling this option increases the complexity of the kernel
1184 and slows down exception handling a tiny bit.
1185
1186 If unsure, say N here.
1187
1188config VM86
1189 bool
1190 default X86_LEGACY_VM86
1191
1192config X86_16BIT
1193 bool "Enable support for 16-bit segments" if EXPERT
1194 default y
1195 depends on MODIFY_LDT_SYSCALL
1196 help
1197 This option is required by programs like Wine to run 16-bit
1198 protected mode legacy code on x86 processors. Disabling
1199 this option saves about 300 bytes on i386, or around 6K text
1200 plus 16K runtime memory on x86-64,
1201
1202config X86_ESPFIX32
1203 def_bool y
1204 depends on X86_16BIT && X86_32
1205
1206config X86_ESPFIX64
1207 def_bool y
1208 depends on X86_16BIT && X86_64
1209
1210config X86_VSYSCALL_EMULATION
1211 bool "Enable vsyscall emulation" if EXPERT
1212 default y
1213 depends on X86_64
1214 help
1215 This enables emulation of the legacy vsyscall page. Disabling
1216 it is roughly equivalent to booting with vsyscall=none, except
1217 that it will also disable the helpful warning if a program
1218 tries to use a vsyscall. With this option set to N, offending
1219 programs will just segfault, citing addresses of the form
1220 0xffffffffff600?00.
1221
1222 This option is required by many programs built before 2013, and
1223 care should be used even with newer programs if set to N.
1224
1225 Disabling this option saves about 7K of kernel size and
1226 possibly 4K of additional runtime pagetable memory.
1227
1228config X86_IOPL_IOPERM
1229 bool "IOPERM and IOPL Emulation"
1230 default y
1231 help
1232 This enables the ioperm() and iopl() syscalls which are necessary
1233 for legacy applications.
1234
1235 Legacy IOPL support is an overbroad mechanism which allows user
1236 space aside of accessing all 65536 I/O ports also to disable
1237 interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1238 capabilities and permission from potentially active security
1239 modules.
1240
1241 The emulation restricts the functionality of the syscall to
1242 only allowing the full range I/O port access, but prevents the
1243 ability to disable interrupts from user space which would be
1244 granted if the hardware IOPL mechanism would be used.
1245
1246config TOSHIBA
1247 tristate "Toshiba Laptop support"
1248 depends on X86_32
1249 help
1250 This adds a driver to safely access the System Management Mode of
1251 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1252 not work on models with a Phoenix BIOS. The System Management Mode
1253 is used to set the BIOS and power saving options on Toshiba portables.
1254
1255 For information on utilities to make use of this driver see the
1256 Toshiba Linux utilities web site at:
1257 <http://www.buzzard.org.uk/toshiba/>.
1258
1259 Say Y if you intend to run this kernel on a Toshiba portable.
1260 Say N otherwise.
1261
1262config I8K
1263 tristate "Dell i8k legacy laptop support"
1264 select HWMON
1265 select SENSORS_DELL_SMM
1266 help
1267 This option enables legacy /proc/i8k userspace interface in hwmon
1268 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1269 temperature and allows controlling fan speeds of Dell laptops via
1270 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1271 it reports also power and hotkey status. For fan speed control is
1272 needed userspace package i8kutils.
1273
1274 Say Y if you intend to run this kernel on old Dell laptops or want to
1275 use userspace package i8kutils.
1276 Say N otherwise.
1277
1278config X86_REBOOTFIXUPS
1279 bool "Enable X86 board specific fixups for reboot"
1280 depends on X86_32
1281 help
1282 This enables chipset and/or board specific fixups to be done
1283 in order to get reboot to work correctly. This is only needed on
1284 some combinations of hardware and BIOS. The symptom, for which
1285 this config is intended, is when reboot ends with a stalled/hung
1286 system.
1287
1288 Currently, the only fixup is for the Geode machines using
1289 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1290
1291 Say Y if you want to enable the fixup. Currently, it's safe to
1292 enable this option even if you don't need it.
1293 Say N otherwise.
1294
1295config MICROCODE
1296 bool "CPU microcode loading support"
1297 default y
1298 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1299 help
1300 If you say Y here, you will be able to update the microcode on
1301 Intel and AMD processors. The Intel support is for the IA32 family,
1302 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1303 AMD support is for families 0x10 and later. You will obviously need
1304 the actual microcode binary data itself which is not shipped with
1305 the Linux kernel.
1306
1307 The preferred method to load microcode from a detached initrd is described
1308 in Documentation/x86/microcode.rst. For that you need to enable
1309 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1310 initrd for microcode blobs.
1311
1312 In addition, you can build the microcode into the kernel. For that you
1313 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1314 config option.
1315
1316config MICROCODE_INTEL
1317 bool "Intel microcode loading support"
1318 depends on MICROCODE
1319 default MICROCODE
1320 help
1321 This options enables microcode patch loading support for Intel
1322 processors.
1323
1324 For the current Intel microcode data package go to
1325 <https://downloadcenter.intel.com> and search for
1326 'Linux Processor Microcode Data File'.
1327
1328config MICROCODE_AMD
1329 bool "AMD microcode loading support"
1330 depends on MICROCODE
1331 help
1332 If you select this option, microcode patch loading support for AMD
1333 processors will be enabled.
1334
1335config MICROCODE_OLD_INTERFACE
1336 bool "Ancient loading interface (DEPRECATED)"
1337 default n
1338 depends on MICROCODE
1339 help
1340 DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1341 which was used by userspace tools like iucode_tool and microcode.ctl.
1342 It is inadequate because it runs too late to be able to properly
1343 load microcode on a machine and it needs special tools. Instead, you
1344 should've switched to the early loading method with the initrd or
1345 builtin microcode by now: Documentation/x86/microcode.rst
1346
1347config X86_MSR
1348 tristate "/dev/cpu/*/msr - Model-specific register support"
1349 help
1350 This device gives privileged processes access to the x86
1351 Model-Specific Registers (MSRs). It is a character device with
1352 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1353 MSR accesses are directed to a specific CPU on multi-processor
1354 systems.
1355
1356config X86_CPUID
1357 tristate "/dev/cpu/*/cpuid - CPU information support"
1358 help
1359 This device gives processes access to the x86 CPUID instruction to
1360 be executed on a specific processor. It is a character device
1361 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1362 /dev/cpu/31/cpuid.
1363
1364choice
1365 prompt "High Memory Support"
1366 default HIGHMEM4G
1367 depends on X86_32
1368
1369config NOHIGHMEM
1370 bool "off"
1371 help
1372 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1373 However, the address space of 32-bit x86 processors is only 4
1374 Gigabytes large. That means that, if you have a large amount of
1375 physical memory, not all of it can be "permanently mapped" by the
1376 kernel. The physical memory that's not permanently mapped is called
1377 "high memory".
1378
1379 If you are compiling a kernel which will never run on a machine with
1380 more than 1 Gigabyte total physical RAM, answer "off" here (default
1381 choice and suitable for most users). This will result in a "3GB/1GB"
1382 split: 3GB are mapped so that each process sees a 3GB virtual memory
1383 space and the remaining part of the 4GB virtual memory space is used
1384 by the kernel to permanently map as much physical memory as
1385 possible.
1386
1387 If the machine has between 1 and 4 Gigabytes physical RAM, then
1388 answer "4GB" here.
1389
1390 If more than 4 Gigabytes is used then answer "64GB" here. This
1391 selection turns Intel PAE (Physical Address Extension) mode on.
1392 PAE implements 3-level paging on IA32 processors. PAE is fully
1393 supported by Linux, PAE mode is implemented on all recent Intel
1394 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1395 then the kernel will not boot on CPUs that don't support PAE!
1396
1397 The actual amount of total physical memory will either be
1398 auto detected or can be forced by using a kernel command line option
1399 such as "mem=256M". (Try "man bootparam" or see the documentation of
1400 your boot loader (lilo or loadlin) about how to pass options to the
1401 kernel at boot time.)
1402
1403 If unsure, say "off".
1404
1405config HIGHMEM4G
1406 bool "4GB"
1407 help
1408 Select this if you have a 32-bit processor and between 1 and 4
1409 gigabytes of physical RAM.
1410
1411config HIGHMEM64G
1412 bool "64GB"
1413 depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
1414 select X86_PAE
1415 help
1416 Select this if you have a 32-bit processor and more than 4
1417 gigabytes of physical RAM.
1418
1419endchoice
1420
1421choice
1422 prompt "Memory split" if EXPERT
1423 default VMSPLIT_3G
1424 depends on X86_32
1425 help
1426 Select the desired split between kernel and user memory.
1427
1428 If the address range available to the kernel is less than the
1429 physical memory installed, the remaining memory will be available
1430 as "high memory". Accessing high memory is a little more costly
1431 than low memory, as it needs to be mapped into the kernel first.
1432 Note that increasing the kernel address space limits the range
1433 available to user programs, making the address space there
1434 tighter. Selecting anything other than the default 3G/1G split
1435 will also likely make your kernel incompatible with binary-only
1436 kernel modules.
1437
1438 If you are not absolutely sure what you are doing, leave this
1439 option alone!
1440
1441 config VMSPLIT_3G
1442 bool "3G/1G user/kernel split"
1443 config VMSPLIT_3G_OPT
1444 depends on !X86_PAE
1445 bool "3G/1G user/kernel split (for full 1G low memory)"
1446 config VMSPLIT_2G
1447 bool "2G/2G user/kernel split"
1448 config VMSPLIT_2G_OPT
1449 depends on !X86_PAE
1450 bool "2G/2G user/kernel split (for full 2G low memory)"
1451 config VMSPLIT_1G
1452 bool "1G/3G user/kernel split"
1453endchoice
1454
1455config PAGE_OFFSET
1456 hex
1457 default 0xB0000000 if VMSPLIT_3G_OPT
1458 default 0x80000000 if VMSPLIT_2G
1459 default 0x78000000 if VMSPLIT_2G_OPT
1460 default 0x40000000 if VMSPLIT_1G
1461 default 0xC0000000
1462 depends on X86_32
1463
1464config HIGHMEM
1465 def_bool y
1466 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1467
1468config X86_PAE
1469 bool "PAE (Physical Address Extension) Support"
1470 depends on X86_32 && !HIGHMEM4G
1471 select PHYS_ADDR_T_64BIT
1472 select SWIOTLB
1473 help
1474 PAE is required for NX support, and furthermore enables
1475 larger swapspace support for non-overcommit purposes. It
1476 has the cost of more pagetable lookup overhead, and also
1477 consumes more pagetable space per process.
1478
1479config X86_5LEVEL
1480 bool "Enable 5-level page tables support"
1481 default y
1482 select DYNAMIC_MEMORY_LAYOUT
1483 select SPARSEMEM_VMEMMAP
1484 depends on X86_64
1485 help
1486 5-level paging enables access to larger address space:
1487 upto 128 PiB of virtual address space and 4 PiB of
1488 physical address space.
1489
1490 It will be supported by future Intel CPUs.
1491
1492 A kernel with the option enabled can be booted on machines that
1493 support 4- or 5-level paging.
1494
1495 See Documentation/x86/x86_64/5level-paging.rst for more
1496 information.
1497
1498 Say N if unsure.
1499
1500config X86_DIRECT_GBPAGES
1501 def_bool y
1502 depends on X86_64
1503 help
1504 Certain kernel features effectively disable kernel
1505 linear 1 GB mappings (even if the CPU otherwise
1506 supports them), so don't confuse the user by printing
1507 that we have them enabled.
1508
1509config X86_CPA_STATISTICS
1510 bool "Enable statistic for Change Page Attribute"
1511 depends on DEBUG_FS
1512 help
1513 Expose statistics about the Change Page Attribute mechanism, which
1514 helps to determine the effectiveness of preserving large and huge
1515 page mappings when mapping protections are changed.
1516
1517config AMD_MEM_ENCRYPT
1518 bool "AMD Secure Memory Encryption (SME) support"
1519 depends on X86_64 && CPU_SUP_AMD
1520 select DMA_COHERENT_POOL
1521 select DYNAMIC_PHYSICAL_MASK
1522 select ARCH_USE_MEMREMAP_PROT
1523 select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1524 help
1525 Say yes to enable support for the encryption of system memory.
1526 This requires an AMD processor that supports Secure Memory
1527 Encryption (SME).
1528
1529config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1530 bool "Activate AMD Secure Memory Encryption (SME) by default"
1531 default y
1532 depends on AMD_MEM_ENCRYPT
1533 help
1534 Say yes to have system memory encrypted by default if running on
1535 an AMD processor that supports Secure Memory Encryption (SME).
1536
1537 If set to Y, then the encryption of system memory can be
1538 deactivated with the mem_encrypt=off command line option.
1539
1540 If set to N, then the encryption of system memory can be
1541 activated with the mem_encrypt=on command line option.
1542
1543# Common NUMA Features
1544config NUMA
1545 bool "NUMA Memory Allocation and Scheduler Support"
1546 depends on SMP
1547 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1548 default y if X86_BIGSMP
1549 help
1550 Enable NUMA (Non-Uniform Memory Access) support.
1551
1552 The kernel will try to allocate memory used by a CPU on the
1553 local memory controller of the CPU and add some more
1554 NUMA awareness to the kernel.
1555
1556 For 64-bit this is recommended if the system is Intel Core i7
1557 (or later), AMD Opteron, or EM64T NUMA.
1558
1559 For 32-bit this is only needed if you boot a 32-bit
1560 kernel on a 64-bit NUMA platform.
1561
1562 Otherwise, you should say N.
1563
1564config AMD_NUMA
1565 def_bool y
1566 prompt "Old style AMD Opteron NUMA detection"
1567 depends on X86_64 && NUMA && PCI
1568 help
1569 Enable AMD NUMA node topology detection. You should say Y here if
1570 you have a multi processor AMD system. This uses an old method to
1571 read the NUMA configuration directly from the builtin Northbridge
1572 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1573 which also takes priority if both are compiled in.
1574
1575config X86_64_ACPI_NUMA
1576 def_bool y
1577 prompt "ACPI NUMA detection"
1578 depends on X86_64 && NUMA && ACPI && PCI
1579 select ACPI_NUMA
1580 help
1581 Enable ACPI SRAT based node topology detection.
1582
1583config NUMA_EMU
1584 bool "NUMA emulation"
1585 depends on NUMA
1586 help
1587 Enable NUMA emulation. A flat machine will be split
1588 into virtual nodes when booted with "numa=fake=N", where N is the
1589 number of nodes. This is only useful for debugging.
1590
1591config NODES_SHIFT
1592 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1593 range 1 10
1594 default "10" if MAXSMP
1595 default "6" if X86_64
1596 default "3"
1597 depends on NEED_MULTIPLE_NODES
1598 help
1599 Specify the maximum number of NUMA Nodes available on the target
1600 system. Increases memory reserved to accommodate various tables.
1601
1602config ARCH_FLATMEM_ENABLE
1603 def_bool y
1604 depends on X86_32 && !NUMA
1605
1606config ARCH_SPARSEMEM_ENABLE
1607 def_bool y
1608 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1609 select SPARSEMEM_STATIC if X86_32
1610 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1611
1612config ARCH_SPARSEMEM_DEFAULT
1613 def_bool X86_64 || (NUMA && X86_32)
1614
1615config ARCH_SELECT_MEMORY_MODEL
1616 def_bool y
1617 depends on ARCH_SPARSEMEM_ENABLE
1618
1619config ARCH_MEMORY_PROBE
1620 bool "Enable sysfs memory/probe interface"
1621 depends on X86_64 && MEMORY_HOTPLUG
1622 help
1623 This option enables a sysfs memory/probe interface for testing.
1624 See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1625 If you are unsure how to answer this question, answer N.
1626
1627config ARCH_PROC_KCORE_TEXT
1628 def_bool y
1629 depends on X86_64 && PROC_KCORE
1630
1631config ILLEGAL_POINTER_VALUE
1632 hex
1633 default 0 if X86_32
1634 default 0xdead000000000000 if X86_64
1635
1636config X86_PMEM_LEGACY_DEVICE
1637 bool
1638
1639config X86_PMEM_LEGACY
1640 tristate "Support non-standard NVDIMMs and ADR protected memory"
1641 depends on PHYS_ADDR_T_64BIT
1642 depends on BLK_DEV
1643 select X86_PMEM_LEGACY_DEVICE
1644 select NUMA_KEEP_MEMINFO if NUMA
1645 select LIBNVDIMM
1646 help
1647 Treat memory marked using the non-standard e820 type of 12 as used
1648 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1649 The kernel will offer these regions to the 'pmem' driver so
1650 they can be used for persistent storage.
1651
1652 Say Y if unsure.
1653
1654config HIGHPTE
1655 bool "Allocate 3rd-level pagetables from highmem"
1656 depends on HIGHMEM
1657 help
1658 The VM uses one page table entry for each page of physical memory.
1659 For systems with a lot of RAM, this can be wasteful of precious
1660 low memory. Setting this option will put user-space page table
1661 entries in high memory.
1662
1663config X86_CHECK_BIOS_CORRUPTION
1664 bool "Check for low memory corruption"
1665 help
1666 Periodically check for memory corruption in low memory, which
1667 is suspected to be caused by BIOS. Even when enabled in the
1668 configuration, it is disabled at runtime. Enable it by
1669 setting "memory_corruption_check=1" on the kernel command
1670 line. By default it scans the low 64k of memory every 60
1671 seconds; see the memory_corruption_check_size and
1672 memory_corruption_check_period parameters in
1673 Documentation/admin-guide/kernel-parameters.rst to adjust this.
1674
1675 When enabled with the default parameters, this option has
1676 almost no overhead, as it reserves a relatively small amount
1677 of memory and scans it infrequently. It both detects corruption
1678 and prevents it from affecting the running system.
1679
1680 It is, however, intended as a diagnostic tool; if repeatable
1681 BIOS-originated corruption always affects the same memory,
1682 you can use memmap= to prevent the kernel from using that
1683 memory.
1684
1685config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1686 bool "Set the default setting of memory_corruption_check"
1687 depends on X86_CHECK_BIOS_CORRUPTION
1688 default y
1689 help
1690 Set whether the default state of memory_corruption_check is
1691 on or off.
1692
1693config X86_RESERVE_LOW
1694 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1695 default 64
1696 range 4 640
1697 help
1698 Specify the amount of low memory to reserve for the BIOS.
1699
1700 The first page contains BIOS data structures that the kernel
1701 must not use, so that page must always be reserved.
1702
1703 By default we reserve the first 64K of physical RAM, as a
1704 number of BIOSes are known to corrupt that memory range
1705 during events such as suspend/resume or monitor cable
1706 insertion, so it must not be used by the kernel.
1707
1708 You can set this to 4 if you are absolutely sure that you
1709 trust the BIOS to get all its memory reservations and usages
1710 right. If you know your BIOS have problems beyond the
1711 default 64K area, you can set this to 640 to avoid using the
1712 entire low memory range.
1713
1714 If you have doubts about the BIOS (e.g. suspend/resume does
1715 not work or there's kernel crashes after certain hardware
1716 hotplug events) then you might want to enable
1717 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1718 typical corruption patterns.
1719
1720 Leave this to the default value of 64 if you are unsure.
1721
1722config MATH_EMULATION
1723 bool
1724 depends on MODIFY_LDT_SYSCALL
1725 prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1726 help
1727 Linux can emulate a math coprocessor (used for floating point
1728 operations) if you don't have one. 486DX and Pentium processors have
1729 a math coprocessor built in, 486SX and 386 do not, unless you added
1730 a 487DX or 387, respectively. (The messages during boot time can
1731 give you some hints here ["man dmesg"].) Everyone needs either a
1732 coprocessor or this emulation.
1733
1734 If you don't have a math coprocessor, you need to say Y here; if you
1735 say Y here even though you have a coprocessor, the coprocessor will
1736 be used nevertheless. (This behavior can be changed with the kernel
1737 command line option "no387", which comes handy if your coprocessor
1738 is broken. Try "man bootparam" or see the documentation of your boot
1739 loader (lilo or loadlin) about how to pass options to the kernel at
1740 boot time.) This means that it is a good idea to say Y here if you
1741 intend to use this kernel on different machines.
1742
1743 More information about the internals of the Linux math coprocessor
1744 emulation can be found in <file:arch/x86/math-emu/README>.
1745
1746 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1747 kernel, it won't hurt.
1748
1749config MTRR
1750 def_bool y
1751 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1752 help
1753 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1754 the Memory Type Range Registers (MTRRs) may be used to control
1755 processor access to memory ranges. This is most useful if you have
1756 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1757 allows bus write transfers to be combined into a larger transfer
1758 before bursting over the PCI/AGP bus. This can increase performance
1759 of image write operations 2.5 times or more. Saying Y here creates a
1760 /proc/mtrr file which may be used to manipulate your processor's
1761 MTRRs. Typically the X server should use this.
1762
1763 This code has a reasonably generic interface so that similar
1764 control registers on other processors can be easily supported
1765 as well:
1766
1767 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1768 Registers (ARRs) which provide a similar functionality to MTRRs. For
1769 these, the ARRs are used to emulate the MTRRs.
1770 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1771 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1772 write-combining. All of these processors are supported by this code
1773 and it makes sense to say Y here if you have one of them.
1774
1775 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1776 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1777 can lead to all sorts of problems, so it's good to say Y here.
1778
1779 You can safely say Y even if your machine doesn't have MTRRs, you'll
1780 just add about 9 KB to your kernel.
1781
1782 See <file:Documentation/x86/mtrr.rst> for more information.
1783
1784config MTRR_SANITIZER
1785 def_bool y
1786 prompt "MTRR cleanup support"
1787 depends on MTRR
1788 help
1789 Convert MTRR layout from continuous to discrete, so X drivers can
1790 add writeback entries.
1791
1792 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1793 The largest mtrr entry size for a continuous block can be set with
1794 mtrr_chunk_size.
1795
1796 If unsure, say Y.
1797
1798config MTRR_SANITIZER_ENABLE_DEFAULT
1799 int "MTRR cleanup enable value (0-1)"
1800 range 0 1
1801 default "0"
1802 depends on MTRR_SANITIZER
1803 help
1804 Enable mtrr cleanup default value
1805
1806config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1807 int "MTRR cleanup spare reg num (0-7)"
1808 range 0 7
1809 default "1"
1810 depends on MTRR_SANITIZER
1811 help
1812 mtrr cleanup spare entries default, it can be changed via
1813 mtrr_spare_reg_nr=N on the kernel command line.
1814
1815config X86_PAT
1816 def_bool y
1817 prompt "x86 PAT support" if EXPERT
1818 depends on MTRR
1819 help
1820 Use PAT attributes to setup page level cache control.
1821
1822 PATs are the modern equivalents of MTRRs and are much more
1823 flexible than MTRRs.
1824
1825 Say N here if you see bootup problems (boot crash, boot hang,
1826 spontaneous reboots) or a non-working video driver.
1827
1828 If unsure, say Y.
1829
1830config ARCH_USES_PG_UNCACHED
1831 def_bool y
1832 depends on X86_PAT
1833
1834config ARCH_RANDOM
1835 def_bool y
1836 prompt "x86 architectural random number generator" if EXPERT
1837 help
1838 Enable the x86 architectural RDRAND instruction
1839 (Intel Bull Mountain technology) to generate random numbers.
1840 If supported, this is a high bandwidth, cryptographically
1841 secure hardware random number generator.
1842
1843config X86_SMAP
1844 def_bool y
1845 prompt "Supervisor Mode Access Prevention" if EXPERT
1846 help
1847 Supervisor Mode Access Prevention (SMAP) is a security
1848 feature in newer Intel processors. There is a small
1849 performance cost if this enabled and turned on; there is
1850 also a small increase in the kernel size if this is enabled.
1851
1852 If unsure, say Y.
1853
1854config X86_UMIP
1855 def_bool y
1856 prompt "User Mode Instruction Prevention" if EXPERT
1857 help
1858 User Mode Instruction Prevention (UMIP) is a security feature in
1859 some x86 processors. If enabled, a general protection fault is
1860 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1861 executed in user mode. These instructions unnecessarily expose
1862 information about the hardware state.
1863
1864 The vast majority of applications do not use these instructions.
1865 For the very few that do, software emulation is provided in
1866 specific cases in protected and virtual-8086 modes. Emulated
1867 results are dummy.
1868
1869config X86_INTEL_MEMORY_PROTECTION_KEYS
1870 prompt "Memory Protection Keys"
1871 def_bool y
1872 # Note: only available in 64-bit mode
1873 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1874 select ARCH_USES_HIGH_VMA_FLAGS
1875 select ARCH_HAS_PKEYS
1876 help
1877 Memory Protection Keys provides a mechanism for enforcing
1878 page-based protections, but without requiring modification of the
1879 page tables when an application changes protection domains.
1880
1881 For details, see Documentation/core-api/protection-keys.rst
1882
1883 If unsure, say y.
1884
1885choice
1886 prompt "TSX enable mode"
1887 depends on CPU_SUP_INTEL
1888 default X86_INTEL_TSX_MODE_OFF
1889 help
1890 Intel's TSX (Transactional Synchronization Extensions) feature
1891 allows to optimize locking protocols through lock elision which
1892 can lead to a noticeable performance boost.
1893
1894 On the other hand it has been shown that TSX can be exploited
1895 to form side channel attacks (e.g. TAA) and chances are there
1896 will be more of those attacks discovered in the future.
1897
1898 Therefore TSX is not enabled by default (aka tsx=off). An admin
1899 might override this decision by tsx=on the command line parameter.
1900 Even with TSX enabled, the kernel will attempt to enable the best
1901 possible TAA mitigation setting depending on the microcode available
1902 for the particular machine.
1903
1904 This option allows to set the default tsx mode between tsx=on, =off
1905 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1906 details.
1907
1908 Say off if not sure, auto if TSX is in use but it should be used on safe
1909 platforms or on if TSX is in use and the security aspect of tsx is not
1910 relevant.
1911
1912config X86_INTEL_TSX_MODE_OFF
1913 bool "off"
1914 help
1915 TSX is disabled if possible - equals to tsx=off command line parameter.
1916
1917config X86_INTEL_TSX_MODE_ON
1918 bool "on"
1919 help
1920 TSX is always enabled on TSX capable HW - equals the tsx=on command
1921 line parameter.
1922
1923config X86_INTEL_TSX_MODE_AUTO
1924 bool "auto"
1925 help
1926 TSX is enabled on TSX capable HW that is believed to be safe against
1927 side channel attacks- equals the tsx=auto command line parameter.
1928endchoice
1929
1930config EFI
1931 bool "EFI runtime service support"
1932 depends on ACPI
1933 select UCS2_STRING
1934 select EFI_RUNTIME_WRAPPERS
1935 help
1936 This enables the kernel to use EFI runtime services that are
1937 available (such as the EFI variable services).
1938
1939 This option is only useful on systems that have EFI firmware.
1940 In addition, you should use the latest ELILO loader available
1941 at <http://elilo.sourceforge.net> in order to take advantage
1942 of EFI runtime services. However, even with this option, the
1943 resultant kernel should continue to boot on existing non-EFI
1944 platforms.
1945
1946config EFI_STUB
1947 bool "EFI stub support"
1948 depends on EFI && !X86_USE_3DNOW
1949 depends on $(cc-option,-mabi=ms) || X86_32
1950 select RELOCATABLE
1951 help
1952 This kernel feature allows a bzImage to be loaded directly
1953 by EFI firmware without the use of a bootloader.
1954
1955 See Documentation/admin-guide/efi-stub.rst for more information.
1956
1957config EFI_MIXED
1958 bool "EFI mixed-mode support"
1959 depends on EFI_STUB && X86_64
1960 help
1961 Enabling this feature allows a 64-bit kernel to be booted
1962 on a 32-bit firmware, provided that your CPU supports 64-bit
1963 mode.
1964
1965 Note that it is not possible to boot a mixed-mode enabled
1966 kernel via the EFI boot stub - a bootloader that supports
1967 the EFI handover protocol must be used.
1968
1969 If unsure, say N.
1970
1971config SECCOMP
1972 def_bool y
1973 prompt "Enable seccomp to safely compute untrusted bytecode"
1974 help
1975 This kernel feature is useful for number crunching applications
1976 that may need to compute untrusted bytecode during their
1977 execution. By using pipes or other transports made available to
1978 the process as file descriptors supporting the read/write
1979 syscalls, it's possible to isolate those applications in
1980 their own address space using seccomp. Once seccomp is
1981 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1982 and the task is only allowed to execute a few safe syscalls
1983 defined by each seccomp mode.
1984
1985 If unsure, say Y. Only embedded should say N here.
1986
1987source "kernel/Kconfig.hz"
1988
1989config KEXEC
1990 bool "kexec system call"
1991 select KEXEC_CORE
1992 help
1993 kexec is a system call that implements the ability to shutdown your
1994 current kernel, and to start another kernel. It is like a reboot
1995 but it is independent of the system firmware. And like a reboot
1996 you can start any kernel with it, not just Linux.
1997
1998 The name comes from the similarity to the exec system call.
1999
2000 It is an ongoing process to be certain the hardware in a machine
2001 is properly shutdown, so do not be surprised if this code does not
2002 initially work for you. As of this writing the exact hardware
2003 interface is strongly in flux, so no good recommendation can be
2004 made.
2005
2006config KEXEC_FILE
2007 bool "kexec file based system call"
2008 select KEXEC_CORE
2009 select BUILD_BIN2C
2010 depends on X86_64
2011 depends on CRYPTO=y
2012 depends on CRYPTO_SHA256=y
2013 help
2014 This is new version of kexec system call. This system call is
2015 file based and takes file descriptors as system call argument
2016 for kernel and initramfs as opposed to list of segments as
2017 accepted by previous system call.
2018
2019config ARCH_HAS_KEXEC_PURGATORY
2020 def_bool KEXEC_FILE
2021
2022config KEXEC_SIG
2023 bool "Verify kernel signature during kexec_file_load() syscall"
2024 depends on KEXEC_FILE
2025 help
2026
2027 This option makes the kexec_file_load() syscall check for a valid
2028 signature of the kernel image. The image can still be loaded without
2029 a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2030 there's a signature that we can check, then it must be valid.
2031
2032 In addition to this option, you need to enable signature
2033 verification for the corresponding kernel image type being
2034 loaded in order for this to work.
2035
2036config KEXEC_SIG_FORCE
2037 bool "Require a valid signature in kexec_file_load() syscall"
2038 depends on KEXEC_SIG
2039 help
2040 This option makes kernel signature verification mandatory for
2041 the kexec_file_load() syscall.
2042
2043config KEXEC_BZIMAGE_VERIFY_SIG
2044 bool "Enable bzImage signature verification support"
2045 depends on KEXEC_SIG
2046 depends on SIGNED_PE_FILE_VERIFICATION
2047 select SYSTEM_TRUSTED_KEYRING
2048 help
2049 Enable bzImage signature verification support.
2050
2051config CRASH_DUMP
2052 bool "kernel crash dumps"
2053 depends on X86_64 || (X86_32 && HIGHMEM)
2054 help
2055 Generate crash dump after being started by kexec.
2056 This should be normally only set in special crash dump kernels
2057 which are loaded in the main kernel with kexec-tools into
2058 a specially reserved region and then later executed after
2059 a crash by kdump/kexec. The crash dump kernel must be compiled
2060 to a memory address not used by the main kernel or BIOS using
2061 PHYSICAL_START, or it must be built as a relocatable image
2062 (CONFIG_RELOCATABLE=y).
2063 For more details see Documentation/admin-guide/kdump/kdump.rst
2064
2065config KEXEC_JUMP
2066 bool "kexec jump"
2067 depends on KEXEC && HIBERNATION
2068 help
2069 Jump between original kernel and kexeced kernel and invoke
2070 code in physical address mode via KEXEC
2071
2072config PHYSICAL_START
2073 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2074 default "0x1000000"
2075 help
2076 This gives the physical address where the kernel is loaded.
2077
2078 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2079 bzImage will decompress itself to above physical address and
2080 run from there. Otherwise, bzImage will run from the address where
2081 it has been loaded by the boot loader and will ignore above physical
2082 address.
2083
2084 In normal kdump cases one does not have to set/change this option
2085 as now bzImage can be compiled as a completely relocatable image
2086 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2087 address. This option is mainly useful for the folks who don't want
2088 to use a bzImage for capturing the crash dump and want to use a
2089 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2090 to be specifically compiled to run from a specific memory area
2091 (normally a reserved region) and this option comes handy.
2092
2093 So if you are using bzImage for capturing the crash dump,
2094 leave the value here unchanged to 0x1000000 and set
2095 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2096 for capturing the crash dump change this value to start of
2097 the reserved region. In other words, it can be set based on
2098 the "X" value as specified in the "crashkernel=YM@XM"
2099 command line boot parameter passed to the panic-ed
2100 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2101 for more details about crash dumps.
2102
2103 Usage of bzImage for capturing the crash dump is recommended as
2104 one does not have to build two kernels. Same kernel can be used
2105 as production kernel and capture kernel. Above option should have
2106 gone away after relocatable bzImage support is introduced. But it
2107 is present because there are users out there who continue to use
2108 vmlinux for dump capture. This option should go away down the
2109 line.
2110
2111 Don't change this unless you know what you are doing.
2112
2113config RELOCATABLE
2114 bool "Build a relocatable kernel"
2115 default y
2116 help
2117 This builds a kernel image that retains relocation information
2118 so it can be loaded someplace besides the default 1MB.
2119 The relocations tend to make the kernel binary about 10% larger,
2120 but are discarded at runtime.
2121
2122 One use is for the kexec on panic case where the recovery kernel
2123 must live at a different physical address than the primary
2124 kernel.
2125
2126 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2127 it has been loaded at and the compile time physical address
2128 (CONFIG_PHYSICAL_START) is used as the minimum location.
2129
2130config RANDOMIZE_BASE
2131 bool "Randomize the address of the kernel image (KASLR)"
2132 depends on RELOCATABLE
2133 default y
2134 help
2135 In support of Kernel Address Space Layout Randomization (KASLR),
2136 this randomizes the physical address at which the kernel image
2137 is decompressed and the virtual address where the kernel
2138 image is mapped, as a security feature that deters exploit
2139 attempts relying on knowledge of the location of kernel
2140 code internals.
2141
2142 On 64-bit, the kernel physical and virtual addresses are
2143 randomized separately. The physical address will be anywhere
2144 between 16MB and the top of physical memory (up to 64TB). The
2145 virtual address will be randomized from 16MB up to 1GB (9 bits
2146 of entropy). Note that this also reduces the memory space
2147 available to kernel modules from 1.5GB to 1GB.
2148
2149 On 32-bit, the kernel physical and virtual addresses are
2150 randomized together. They will be randomized from 16MB up to
2151 512MB (8 bits of entropy).
2152
2153 Entropy is generated using the RDRAND instruction if it is
2154 supported. If RDTSC is supported, its value is mixed into
2155 the entropy pool as well. If neither RDRAND nor RDTSC are
2156 supported, then entropy is read from the i8254 timer. The
2157 usable entropy is limited by the kernel being built using
2158 2GB addressing, and that PHYSICAL_ALIGN must be at a
2159 minimum of 2MB. As a result, only 10 bits of entropy are
2160 theoretically possible, but the implementations are further
2161 limited due to memory layouts.
2162
2163 If unsure, say Y.
2164
2165# Relocation on x86 needs some additional build support
2166config X86_NEED_RELOCS
2167 def_bool y
2168 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2169
2170config PHYSICAL_ALIGN
2171 hex "Alignment value to which kernel should be aligned"
2172 default "0x200000"
2173 range 0x2000 0x1000000 if X86_32
2174 range 0x200000 0x1000000 if X86_64
2175 help
2176 This value puts the alignment restrictions on physical address
2177 where kernel is loaded and run from. Kernel is compiled for an
2178 address which meets above alignment restriction.
2179
2180 If bootloader loads the kernel at a non-aligned address and
2181 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2182 address aligned to above value and run from there.
2183
2184 If bootloader loads the kernel at a non-aligned address and
2185 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2186 load address and decompress itself to the address it has been
2187 compiled for and run from there. The address for which kernel is
2188 compiled already meets above alignment restrictions. Hence the
2189 end result is that kernel runs from a physical address meeting
2190 above alignment restrictions.
2191
2192 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2193 this value must be a multiple of 0x200000.
2194
2195 Don't change this unless you know what you are doing.
2196
2197config DYNAMIC_MEMORY_LAYOUT
2198 bool
2199 help
2200 This option makes base addresses of vmalloc and vmemmap as well as
2201 __PAGE_OFFSET movable during boot.
2202
2203config RANDOMIZE_MEMORY
2204 bool "Randomize the kernel memory sections"
2205 depends on X86_64
2206 depends on RANDOMIZE_BASE
2207 select DYNAMIC_MEMORY_LAYOUT
2208 default RANDOMIZE_BASE
2209 help
2210 Randomizes the base virtual address of kernel memory sections
2211 (physical memory mapping, vmalloc & vmemmap). This security feature
2212 makes exploits relying on predictable memory locations less reliable.
2213
2214 The order of allocations remains unchanged. Entropy is generated in
2215 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2216 configuration have in average 30,000 different possible virtual
2217 addresses for each memory section.
2218
2219 If unsure, say Y.
2220
2221config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2222 hex "Physical memory mapping padding" if EXPERT
2223 depends on RANDOMIZE_MEMORY
2224 default "0xa" if MEMORY_HOTPLUG
2225 default "0x0"
2226 range 0x1 0x40 if MEMORY_HOTPLUG
2227 range 0x0 0x40
2228 help
2229 Define the padding in terabytes added to the existing physical
2230 memory size during kernel memory randomization. It is useful
2231 for memory hotplug support but reduces the entropy available for
2232 address randomization.
2233
2234 If unsure, leave at the default value.
2235
2236config HOTPLUG_CPU
2237 def_bool y
2238 depends on SMP
2239
2240config BOOTPARAM_HOTPLUG_CPU0
2241 bool "Set default setting of cpu0_hotpluggable"
2242 depends on HOTPLUG_CPU
2243 help
2244 Set whether default state of cpu0_hotpluggable is on or off.
2245
2246 Say Y here to enable CPU0 hotplug by default. If this switch
2247 is turned on, there is no need to give cpu0_hotplug kernel
2248 parameter and the CPU0 hotplug feature is enabled by default.
2249
2250 Please note: there are two known CPU0 dependencies if you want
2251 to enable the CPU0 hotplug feature either by this switch or by
2252 cpu0_hotplug kernel parameter.
2253
2254 First, resume from hibernate or suspend always starts from CPU0.
2255 So hibernate and suspend are prevented if CPU0 is offline.
2256
2257 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2258 offline if any interrupt can not migrate out of CPU0. There may
2259 be other CPU0 dependencies.
2260
2261 Please make sure the dependencies are under your control before
2262 you enable this feature.
2263
2264 Say N if you don't want to enable CPU0 hotplug feature by default.
2265 You still can enable the CPU0 hotplug feature at boot by kernel
2266 parameter cpu0_hotplug.
2267
2268config DEBUG_HOTPLUG_CPU0
2269 def_bool n
2270 prompt "Debug CPU0 hotplug"
2271 depends on HOTPLUG_CPU
2272 help
2273 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2274 soon as possible and boots up userspace with CPU0 offlined. User
2275 can online CPU0 back after boot time.
2276
2277 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2278 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2279 compilation or giving cpu0_hotplug kernel parameter at boot.
2280
2281 If unsure, say N.
2282
2283config COMPAT_VDSO
2284 def_bool n
2285 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2286 depends on COMPAT_32
2287 help
2288 Certain buggy versions of glibc will crash if they are
2289 presented with a 32-bit vDSO that is not mapped at the address
2290 indicated in its segment table.
2291
2292 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2293 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2294 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2295 the only released version with the bug, but OpenSUSE 9
2296 contains a buggy "glibc 2.3.2".
2297
2298 The symptom of the bug is that everything crashes on startup, saying:
2299 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2300
2301 Saying Y here changes the default value of the vdso32 boot
2302 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2303 This works around the glibc bug but hurts performance.
2304
2305 If unsure, say N: if you are compiling your own kernel, you
2306 are unlikely to be using a buggy version of glibc.
2307
2308choice
2309 prompt "vsyscall table for legacy applications"
2310 depends on X86_64
2311 default LEGACY_VSYSCALL_XONLY
2312 help
2313 Legacy user code that does not know how to find the vDSO expects
2314 to be able to issue three syscalls by calling fixed addresses in
2315 kernel space. Since this location is not randomized with ASLR,
2316 it can be used to assist security vulnerability exploitation.
2317
2318 This setting can be changed at boot time via the kernel command
2319 line parameter vsyscall=[emulate|xonly|none].
2320
2321 On a system with recent enough glibc (2.14 or newer) and no
2322 static binaries, you can say None without a performance penalty
2323 to improve security.
2324
2325 If unsure, select "Emulate execution only".
2326
2327 config LEGACY_VSYSCALL_EMULATE
2328 bool "Full emulation"
2329 help
2330 The kernel traps and emulates calls into the fixed vsyscall
2331 address mapping. This makes the mapping non-executable, but
2332 it still contains readable known contents, which could be
2333 used in certain rare security vulnerability exploits. This
2334 configuration is recommended when using legacy userspace
2335 that still uses vsyscalls along with legacy binary
2336 instrumentation tools that require code to be readable.
2337
2338 An example of this type of legacy userspace is running
2339 Pin on an old binary that still uses vsyscalls.
2340
2341 config LEGACY_VSYSCALL_XONLY
2342 bool "Emulate execution only"
2343 help
2344 The kernel traps and emulates calls into the fixed vsyscall
2345 address mapping and does not allow reads. This
2346 configuration is recommended when userspace might use the
2347 legacy vsyscall area but support for legacy binary
2348 instrumentation of legacy code is not needed. It mitigates
2349 certain uses of the vsyscall area as an ASLR-bypassing
2350 buffer.
2351
2352 config LEGACY_VSYSCALL_NONE
2353 bool "None"
2354 help
2355 There will be no vsyscall mapping at all. This will
2356 eliminate any risk of ASLR bypass due to the vsyscall
2357 fixed address mapping. Attempts to use the vsyscalls
2358 will be reported to dmesg, so that either old or
2359 malicious userspace programs can be identified.
2360
2361endchoice
2362
2363config CMDLINE_BOOL
2364 bool "Built-in kernel command line"
2365 help
2366 Allow for specifying boot arguments to the kernel at
2367 build time. On some systems (e.g. embedded ones), it is
2368 necessary or convenient to provide some or all of the
2369 kernel boot arguments with the kernel itself (that is,
2370 to not rely on the boot loader to provide them.)
2371
2372 To compile command line arguments into the kernel,
2373 set this option to 'Y', then fill in the
2374 boot arguments in CONFIG_CMDLINE.
2375
2376 Systems with fully functional boot loaders (i.e. non-embedded)
2377 should leave this option set to 'N'.
2378
2379config CMDLINE
2380 string "Built-in kernel command string"
2381 depends on CMDLINE_BOOL
2382 default ""
2383 help
2384 Enter arguments here that should be compiled into the kernel
2385 image and used at boot time. If the boot loader provides a
2386 command line at boot time, it is appended to this string to
2387 form the full kernel command line, when the system boots.
2388
2389 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2390 change this behavior.
2391
2392 In most cases, the command line (whether built-in or provided
2393 by the boot loader) should specify the device for the root
2394 file system.
2395
2396config CMDLINE_OVERRIDE
2397 bool "Built-in command line overrides boot loader arguments"
2398 depends on CMDLINE_BOOL && CMDLINE != ""
2399 help
2400 Set this option to 'Y' to have the kernel ignore the boot loader
2401 command line, and use ONLY the built-in command line.
2402
2403 This is used to work around broken boot loaders. This should
2404 be set to 'N' under normal conditions.
2405
2406config MODIFY_LDT_SYSCALL
2407 bool "Enable the LDT (local descriptor table)" if EXPERT
2408 default y
2409 help
2410 Linux can allow user programs to install a per-process x86
2411 Local Descriptor Table (LDT) using the modify_ldt(2) system
2412 call. This is required to run 16-bit or segmented code such as
2413 DOSEMU or some Wine programs. It is also used by some very old
2414 threading libraries.
2415
2416 Enabling this feature adds a small amount of overhead to
2417 context switches and increases the low-level kernel attack
2418 surface. Disabling it removes the modify_ldt(2) system call.
2419
2420 Saying 'N' here may make sense for embedded or server kernels.
2421
2422source "kernel/livepatch/Kconfig"
2423
2424endmenu
2425
2426config ARCH_HAS_ADD_PAGES
2427 def_bool y
2428 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2429
2430config ARCH_ENABLE_MEMORY_HOTPLUG
2431 def_bool y
2432 depends on X86_64 || (X86_32 && HIGHMEM)
2433
2434config ARCH_ENABLE_MEMORY_HOTREMOVE
2435 def_bool y
2436 depends on MEMORY_HOTPLUG
2437
2438config USE_PERCPU_NUMA_NODE_ID
2439 def_bool y
2440 depends on NUMA
2441
2442config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2443 def_bool y
2444 depends on X86_64 || X86_PAE
2445
2446config ARCH_ENABLE_HUGEPAGE_MIGRATION
2447 def_bool y
2448 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2449
2450config ARCH_ENABLE_THP_MIGRATION
2451 def_bool y
2452 depends on X86_64 && TRANSPARENT_HUGEPAGE
2453
2454menu "Power management and ACPI options"
2455
2456config ARCH_HIBERNATION_HEADER
2457 def_bool y
2458 depends on HIBERNATION
2459
2460source "kernel/power/Kconfig"
2461
2462source "drivers/acpi/Kconfig"
2463
2464source "drivers/sfi/Kconfig"
2465
2466config X86_APM_BOOT
2467 def_bool y
2468 depends on APM
2469
2470menuconfig APM
2471 tristate "APM (Advanced Power Management) BIOS support"
2472 depends on X86_32 && PM_SLEEP
2473 help
2474 APM is a BIOS specification for saving power using several different
2475 techniques. This is mostly useful for battery powered laptops with
2476 APM compliant BIOSes. If you say Y here, the system time will be
2477 reset after a RESUME operation, the /proc/apm device will provide
2478 battery status information, and user-space programs will receive
2479 notification of APM "events" (e.g. battery status change).
2480
2481 If you select "Y" here, you can disable actual use of the APM
2482 BIOS by passing the "apm=off" option to the kernel at boot time.
2483
2484 Note that the APM support is almost completely disabled for
2485 machines with more than one CPU.
2486
2487 In order to use APM, you will need supporting software. For location
2488 and more information, read <file:Documentation/power/apm-acpi.rst>
2489 and the Battery Powered Linux mini-HOWTO, available from
2490 <http://www.tldp.org/docs.html#howto>.
2491
2492 This driver does not spin down disk drives (see the hdparm(8)
2493 manpage ("man 8 hdparm") for that), and it doesn't turn off
2494 VESA-compliant "green" monitors.
2495
2496 This driver does not support the TI 4000M TravelMate and the ACER
2497 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2498 desktop machines also don't have compliant BIOSes, and this driver
2499 may cause those machines to panic during the boot phase.
2500
2501 Generally, if you don't have a battery in your machine, there isn't
2502 much point in using this driver and you should say N. If you get
2503 random kernel OOPSes or reboots that don't seem to be related to
2504 anything, try disabling/enabling this option (or disabling/enabling
2505 APM in your BIOS).
2506
2507 Some other things you should try when experiencing seemingly random,
2508 "weird" problems:
2509
2510 1) make sure that you have enough swap space and that it is
2511 enabled.
2512 2) pass the "no-hlt" option to the kernel
2513 3) switch on floating point emulation in the kernel and pass
2514 the "no387" option to the kernel
2515 4) pass the "floppy=nodma" option to the kernel
2516 5) pass the "mem=4M" option to the kernel (thereby disabling
2517 all but the first 4 MB of RAM)
2518 6) make sure that the CPU is not over clocked.
2519 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2520 8) disable the cache from your BIOS settings
2521 9) install a fan for the video card or exchange video RAM
2522 10) install a better fan for the CPU
2523 11) exchange RAM chips
2524 12) exchange the motherboard.
2525
2526 To compile this driver as a module, choose M here: the
2527 module will be called apm.
2528
2529if APM
2530
2531config APM_IGNORE_USER_SUSPEND
2532 bool "Ignore USER SUSPEND"
2533 help
2534 This option will ignore USER SUSPEND requests. On machines with a
2535 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2536 series notebooks, it is necessary to say Y because of a BIOS bug.
2537
2538config APM_DO_ENABLE
2539 bool "Enable PM at boot time"
2540 help
2541 Enable APM features at boot time. From page 36 of the APM BIOS
2542 specification: "When disabled, the APM BIOS does not automatically
2543 power manage devices, enter the Standby State, enter the Suspend
2544 State, or take power saving steps in response to CPU Idle calls."
2545 This driver will make CPU Idle calls when Linux is idle (unless this
2546 feature is turned off -- see "Do CPU IDLE calls", below). This
2547 should always save battery power, but more complicated APM features
2548 will be dependent on your BIOS implementation. You may need to turn
2549 this option off if your computer hangs at boot time when using APM
2550 support, or if it beeps continuously instead of suspending. Turn
2551 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2552 T400CDT. This is off by default since most machines do fine without
2553 this feature.
2554
2555config APM_CPU_IDLE
2556 depends on CPU_IDLE
2557 bool "Make CPU Idle calls when idle"
2558 help
2559 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2560 On some machines, this can activate improved power savings, such as
2561 a slowed CPU clock rate, when the machine is idle. These idle calls
2562 are made after the idle loop has run for some length of time (e.g.,
2563 333 mS). On some machines, this will cause a hang at boot time or
2564 whenever the CPU becomes idle. (On machines with more than one CPU,
2565 this option does nothing.)
2566
2567config APM_DISPLAY_BLANK
2568 bool "Enable console blanking using APM"
2569 help
2570 Enable console blanking using the APM. Some laptops can use this to
2571 turn off the LCD backlight when the screen blanker of the Linux
2572 virtual console blanks the screen. Note that this is only used by
2573 the virtual console screen blanker, and won't turn off the backlight
2574 when using the X Window system. This also doesn't have anything to
2575 do with your VESA-compliant power-saving monitor. Further, this
2576 option doesn't work for all laptops -- it might not turn off your
2577 backlight at all, or it might print a lot of errors to the console,
2578 especially if you are using gpm.
2579
2580config APM_ALLOW_INTS
2581 bool "Allow interrupts during APM BIOS calls"
2582 help
2583 Normally we disable external interrupts while we are making calls to
2584 the APM BIOS as a measure to lessen the effects of a badly behaving
2585 BIOS implementation. The BIOS should reenable interrupts if it
2586 needs to. Unfortunately, some BIOSes do not -- especially those in
2587 many of the newer IBM Thinkpads. If you experience hangs when you
2588 suspend, try setting this to Y. Otherwise, say N.
2589
2590endif # APM
2591
2592source "drivers/cpufreq/Kconfig"
2593
2594source "drivers/cpuidle/Kconfig"
2595
2596source "drivers/idle/Kconfig"
2597
2598endmenu
2599
2600
2601menu "Bus options (PCI etc.)"
2602
2603choice
2604 prompt "PCI access mode"
2605 depends on X86_32 && PCI
2606 default PCI_GOANY
2607 help
2608 On PCI systems, the BIOS can be used to detect the PCI devices and
2609 determine their configuration. However, some old PCI motherboards
2610 have BIOS bugs and may crash if this is done. Also, some embedded
2611 PCI-based systems don't have any BIOS at all. Linux can also try to
2612 detect the PCI hardware directly without using the BIOS.
2613
2614 With this option, you can specify how Linux should detect the
2615 PCI devices. If you choose "BIOS", the BIOS will be used,
2616 if you choose "Direct", the BIOS won't be used, and if you
2617 choose "MMConfig", then PCI Express MMCONFIG will be used.
2618 If you choose "Any", the kernel will try MMCONFIG, then the
2619 direct access method and falls back to the BIOS if that doesn't
2620 work. If unsure, go with the default, which is "Any".
2621
2622config PCI_GOBIOS
2623 bool "BIOS"
2624
2625config PCI_GOMMCONFIG
2626 bool "MMConfig"
2627
2628config PCI_GODIRECT
2629 bool "Direct"
2630
2631config PCI_GOOLPC
2632 bool "OLPC XO-1"
2633 depends on OLPC
2634
2635config PCI_GOANY
2636 bool "Any"
2637
2638endchoice
2639
2640config PCI_BIOS
2641 def_bool y
2642 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2643
2644# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2645config PCI_DIRECT
2646 def_bool y
2647 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2648
2649config PCI_MMCONFIG
2650 bool "Support mmconfig PCI config space access" if X86_64
2651 default y
2652 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
2653 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2654
2655config PCI_OLPC
2656 def_bool y
2657 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2658
2659config PCI_XEN
2660 def_bool y
2661 depends on PCI && XEN
2662 select SWIOTLB_XEN
2663
2664config MMCONF_FAM10H
2665 def_bool y
2666 depends on X86_64 && PCI_MMCONFIG && ACPI
2667
2668config PCI_CNB20LE_QUIRK
2669 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2670 depends on PCI
2671 help
2672 Read the PCI windows out of the CNB20LE host bridge. This allows
2673 PCI hotplug to work on systems with the CNB20LE chipset which do
2674 not have ACPI.
2675
2676 There's no public spec for this chipset, and this functionality
2677 is known to be incomplete.
2678
2679 You should say N unless you know you need this.
2680
2681config ISA_BUS
2682 bool "ISA bus support on modern systems" if EXPERT
2683 help
2684 Expose ISA bus device drivers and options available for selection and
2685 configuration. Enable this option if your target machine has an ISA
2686 bus. ISA is an older system, displaced by PCI and newer bus
2687 architectures -- if your target machine is modern, it probably does
2688 not have an ISA bus.
2689
2690 If unsure, say N.
2691
2692# x86_64 have no ISA slots, but can have ISA-style DMA.
2693config ISA_DMA_API
2694 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2695 default y
2696 help
2697 Enables ISA-style DMA support for devices requiring such controllers.
2698 If unsure, say Y.
2699
2700if X86_32
2701
2702config ISA
2703 bool "ISA support"
2704 help
2705 Find out whether you have ISA slots on your motherboard. ISA is the
2706 name of a bus system, i.e. the way the CPU talks to the other stuff
2707 inside your box. Other bus systems are PCI, EISA, MicroChannel
2708 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2709 newer boards don't support it. If you have ISA, say Y, otherwise N.
2710
2711config SCx200
2712 tristate "NatSemi SCx200 support"
2713 help
2714 This provides basic support for National Semiconductor's
2715 (now AMD's) Geode processors. The driver probes for the
2716 PCI-IDs of several on-chip devices, so its a good dependency
2717 for other scx200_* drivers.
2718
2719 If compiled as a module, the driver is named scx200.
2720
2721config SCx200HR_TIMER
2722 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2723 depends on SCx200
2724 default y
2725 help
2726 This driver provides a clocksource built upon the on-chip
2727 27MHz high-resolution timer. Its also a workaround for
2728 NSC Geode SC-1100's buggy TSC, which loses time when the
2729 processor goes idle (as is done by the scheduler). The
2730 other workaround is idle=poll boot option.
2731
2732config OLPC
2733 bool "One Laptop Per Child support"
2734 depends on !X86_PAE
2735 select GPIOLIB
2736 select OF
2737 select OF_PROMTREE
2738 select IRQ_DOMAIN
2739 select OLPC_EC
2740 help
2741 Add support for detecting the unique features of the OLPC
2742 XO hardware.
2743
2744config OLPC_XO1_PM
2745 bool "OLPC XO-1 Power Management"
2746 depends on OLPC && MFD_CS5535=y && PM_SLEEP
2747 help
2748 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2749
2750config OLPC_XO1_RTC
2751 bool "OLPC XO-1 Real Time Clock"
2752 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2753 help
2754 Add support for the XO-1 real time clock, which can be used as a
2755 programmable wakeup source.
2756
2757config OLPC_XO1_SCI
2758 bool "OLPC XO-1 SCI extras"
2759 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2760 depends on INPUT=y
2761 select POWER_SUPPLY
2762 help
2763 Add support for SCI-based features of the OLPC XO-1 laptop:
2764 - EC-driven system wakeups
2765 - Power button
2766 - Ebook switch
2767 - Lid switch
2768 - AC adapter status updates
2769 - Battery status updates
2770
2771config OLPC_XO15_SCI
2772 bool "OLPC XO-1.5 SCI extras"
2773 depends on OLPC && ACPI
2774 select POWER_SUPPLY
2775 help
2776 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2777 - EC-driven system wakeups
2778 - AC adapter status updates
2779 - Battery status updates
2780
2781config ALIX
2782 bool "PCEngines ALIX System Support (LED setup)"
2783 select GPIOLIB
2784 help
2785 This option enables system support for the PCEngines ALIX.
2786 At present this just sets up LEDs for GPIO control on
2787 ALIX2/3/6 boards. However, other system specific setup should
2788 get added here.
2789
2790 Note: You must still enable the drivers for GPIO and LED support
2791 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2792
2793 Note: You have to set alix.force=1 for boards with Award BIOS.
2794
2795config NET5501
2796 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2797 select GPIOLIB
2798 help
2799 This option enables system support for the Soekris Engineering net5501.
2800
2801config GEOS
2802 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2803 select GPIOLIB
2804 depends on DMI
2805 help
2806 This option enables system support for the Traverse Technologies GEOS.
2807
2808config TS5500
2809 bool "Technologic Systems TS-5500 platform support"
2810 depends on MELAN
2811 select CHECK_SIGNATURE
2812 select NEW_LEDS
2813 select LEDS_CLASS
2814 help
2815 This option enables system support for the Technologic Systems TS-5500.
2816
2817endif # X86_32
2818
2819config AMD_NB
2820 def_bool y
2821 depends on CPU_SUP_AMD && PCI
2822
2823config X86_SYSFB
2824 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2825 help
2826 Firmwares often provide initial graphics framebuffers so the BIOS,
2827 bootloader or kernel can show basic video-output during boot for
2828 user-guidance and debugging. Historically, x86 used the VESA BIOS
2829 Extensions and EFI-framebuffers for this, which are mostly limited
2830 to x86.
2831 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2832 framebuffers so the new generic system-framebuffer drivers can be
2833 used on x86. If the framebuffer is not compatible with the generic
2834 modes, it is advertised as fallback platform framebuffer so legacy
2835 drivers like efifb, vesafb and uvesafb can pick it up.
2836 If this option is not selected, all system framebuffers are always
2837 marked as fallback platform framebuffers as usual.
2838
2839 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2840 not be able to pick up generic system framebuffers if this option
2841 is selected. You are highly encouraged to enable simplefb as
2842 replacement if you select this option. simplefb can correctly deal
2843 with generic system framebuffers. But you should still keep vesafb
2844 and others enabled as fallback if a system framebuffer is
2845 incompatible with simplefb.
2846
2847 If unsure, say Y.
2848
2849endmenu
2850
2851
2852menu "Binary Emulations"
2853
2854config IA32_EMULATION
2855 bool "IA32 Emulation"
2856 depends on X86_64
2857 select ARCH_WANT_OLD_COMPAT_IPC
2858 select BINFMT_ELF
2859 select COMPAT_BINFMT_ELF
2860 select COMPAT_OLD_SIGACTION
2861 help
2862 Include code to run legacy 32-bit programs under a
2863 64-bit kernel. You should likely turn this on, unless you're
2864 100% sure that you don't have any 32-bit programs left.
2865
2866config IA32_AOUT
2867 tristate "IA32 a.out support"
2868 depends on IA32_EMULATION
2869 depends on BROKEN
2870 help
2871 Support old a.out binaries in the 32bit emulation.
2872
2873config X86_X32
2874 bool "x32 ABI for 64-bit mode"
2875 depends on X86_64
2876 help
2877 Include code to run binaries for the x32 native 32-bit ABI
2878 for 64-bit processors. An x32 process gets access to the
2879 full 64-bit register file and wide data path while leaving
2880 pointers at 32 bits for smaller memory footprint.
2881
2882 You will need a recent binutils (2.22 or later) with
2883 elf32_x86_64 support enabled to compile a kernel with this
2884 option set.
2885
2886config COMPAT_32
2887 def_bool y
2888 depends on IA32_EMULATION || X86_32
2889 select HAVE_UID16
2890 select OLD_SIGSUSPEND3
2891
2892config COMPAT
2893 def_bool y
2894 depends on IA32_EMULATION || X86_X32
2895
2896if COMPAT
2897config COMPAT_FOR_U64_ALIGNMENT
2898 def_bool y
2899
2900config SYSVIPC_COMPAT
2901 def_bool y
2902 depends on SYSVIPC
2903endif
2904
2905endmenu
2906
2907
2908config HAVE_ATOMIC_IOMAP
2909 def_bool y
2910 depends on X86_32
2911
2912source "drivers/firmware/Kconfig"
2913
2914source "arch/x86/kvm/Kconfig"
2915
2916source "arch/x86/Kconfig.assembler"