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1config ARM64
2 def_bool y
3 select ACPI_CCA_REQUIRED if ACPI
4 select ACPI_GENERIC_GSI if ACPI
5 select ACPI_GTDT if ACPI
6 select ACPI_IORT if ACPI
7 select ACPI_REDUCED_HARDWARE_ONLY if ACPI
8 select ACPI_MCFG if ACPI
9 select ACPI_SPCR_TABLE if ACPI
10 select ARCH_CLOCKSOURCE_DATA
11 select ARCH_HAS_DEBUG_VIRTUAL
12 select ARCH_HAS_DEVMEM_IS_ALLOWED
13 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
14 select ARCH_HAS_ELF_RANDOMIZE
15 select ARCH_HAS_FORTIFY_SOURCE
16 select ARCH_HAS_GCOV_PROFILE_ALL
17 select ARCH_HAS_GIGANTIC_PAGE if (MEMORY_ISOLATION && COMPACTION) || CMA
18 select ARCH_HAS_KCOV
19 select ARCH_HAS_MEMBARRIER_SYNC_CORE
20 select ARCH_HAS_SET_MEMORY
21 select ARCH_HAS_SG_CHAIN
22 select ARCH_HAS_STRICT_KERNEL_RWX
23 select ARCH_HAS_STRICT_MODULE_RWX
24 select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
25 select ARCH_HAVE_NMI_SAFE_CMPXCHG
26 select ARCH_INLINE_READ_LOCK if !PREEMPT
27 select ARCH_INLINE_READ_LOCK_BH if !PREEMPT
28 select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPT
29 select ARCH_INLINE_READ_LOCK_IRQSAVE if !PREEMPT
30 select ARCH_INLINE_READ_UNLOCK if !PREEMPT
31 select ARCH_INLINE_READ_UNLOCK_BH if !PREEMPT
32 select ARCH_INLINE_READ_UNLOCK_IRQ if !PREEMPT
33 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE if !PREEMPT
34 select ARCH_INLINE_WRITE_LOCK if !PREEMPT
35 select ARCH_INLINE_WRITE_LOCK_BH if !PREEMPT
36 select ARCH_INLINE_WRITE_LOCK_IRQ if !PREEMPT
37 select ARCH_INLINE_WRITE_LOCK_IRQSAVE if !PREEMPT
38 select ARCH_INLINE_WRITE_UNLOCK if !PREEMPT
39 select ARCH_INLINE_WRITE_UNLOCK_BH if !PREEMPT
40 select ARCH_INLINE_WRITE_UNLOCK_IRQ if !PREEMPT
41 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE if !PREEMPT
42 select ARCH_USE_CMPXCHG_LOCKREF
43 select ARCH_USE_QUEUED_RWLOCKS
44 select ARCH_SUPPORTS_MEMORY_FAILURE
45 select ARCH_SUPPORTS_ATOMIC_RMW
46 select ARCH_SUPPORTS_NUMA_BALANCING
47 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
48 select ARCH_WANT_FRAME_POINTERS
49 select ARCH_HAS_UBSAN_SANITIZE_ALL
50 select ARM_AMBA
51 select ARM_ARCH_TIMER
52 select ARM_GIC
53 select AUDIT_ARCH_COMPAT_GENERIC
54 select ARM_GIC_V2M if PCI
55 select ARM_GIC_V3
56 select ARM_GIC_V3_ITS if PCI
57 select ARM_PSCI_FW
58 select BUILDTIME_EXTABLE_SORT
59 select CLONE_BACKWARDS
60 select COMMON_CLK
61 select CPU_PM if (SUSPEND || CPU_IDLE)
62 select DCACHE_WORD_ACCESS
63 select DMA_DIRECT_OPS
64 select EDAC_SUPPORT
65 select FRAME_POINTER
66 select GENERIC_ALLOCATOR
67 select GENERIC_ARCH_TOPOLOGY
68 select GENERIC_CLOCKEVENTS
69 select GENERIC_CLOCKEVENTS_BROADCAST
70 select GENERIC_CPU_AUTOPROBE
71 select GENERIC_EARLY_IOREMAP
72 select GENERIC_IDLE_POLL_SETUP
73 select GENERIC_IRQ_PROBE
74 select GENERIC_IRQ_SHOW
75 select GENERIC_IRQ_SHOW_LEVEL
76 select GENERIC_PCI_IOMAP
77 select GENERIC_SCHED_CLOCK
78 select GENERIC_SMP_IDLE_THREAD
79 select GENERIC_STRNCPY_FROM_USER
80 select GENERIC_STRNLEN_USER
81 select GENERIC_TIME_VSYSCALL
82 select HANDLE_DOMAIN_IRQ
83 select HARDIRQS_SW_RESEND
84 select HAVE_ACPI_APEI if (ACPI && EFI)
85 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
86 select HAVE_ARCH_AUDITSYSCALL
87 select HAVE_ARCH_BITREVERSE
88 select HAVE_ARCH_HUGE_VMAP
89 select HAVE_ARCH_JUMP_LABEL
90 select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
91 select HAVE_ARCH_KGDB
92 select HAVE_ARCH_MMAP_RND_BITS
93 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
94 select HAVE_ARCH_SECCOMP_FILTER
95 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
96 select HAVE_ARCH_TRACEHOOK
97 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
98 select HAVE_ARCH_VMAP_STACK
99 select HAVE_ARM_SMCCC
100 select HAVE_EBPF_JIT
101 select HAVE_C_RECORDMCOUNT
102 select HAVE_CC_STACKPROTECTOR
103 select HAVE_CMPXCHG_DOUBLE
104 select HAVE_CMPXCHG_LOCAL
105 select HAVE_CONTEXT_TRACKING
106 select HAVE_DEBUG_BUGVERBOSE
107 select HAVE_DEBUG_KMEMLEAK
108 select HAVE_DMA_API_DEBUG
109 select HAVE_DMA_CONTIGUOUS
110 select HAVE_DYNAMIC_FTRACE
111 select HAVE_EFFICIENT_UNALIGNED_ACCESS
112 select HAVE_FTRACE_MCOUNT_RECORD
113 select HAVE_FUNCTION_TRACER
114 select HAVE_FUNCTION_GRAPH_TRACER
115 select HAVE_GCC_PLUGINS
116 select HAVE_GENERIC_DMA_COHERENT
117 select HAVE_HW_BREAKPOINT if PERF_EVENTS
118 select HAVE_IRQ_TIME_ACCOUNTING
119 select HAVE_MEMBLOCK
120 select HAVE_MEMBLOCK_NODE_MAP if NUMA
121 select HAVE_NMI
122 select HAVE_PATA_PLATFORM
123 select HAVE_PERF_EVENTS
124 select HAVE_PERF_REGS
125 select HAVE_PERF_USER_STACK_DUMP
126 select HAVE_REGS_AND_STACK_ACCESS_API
127 select HAVE_RCU_TABLE_FREE
128 select HAVE_SYSCALL_TRACEPOINTS
129 select HAVE_KPROBES
130 select HAVE_KRETPROBES
131 select IOMMU_DMA if IOMMU_SUPPORT
132 select IRQ_DOMAIN
133 select IRQ_FORCED_THREADING
134 select MODULES_USE_ELF_RELA
135 select MULTI_IRQ_HANDLER
136 select NO_BOOTMEM
137 select OF
138 select OF_EARLY_FLATTREE
139 select OF_RESERVED_MEM
140 select PCI_ECAM if ACPI
141 select POWER_RESET
142 select POWER_SUPPLY
143 select REFCOUNT_FULL
144 select SPARSE_IRQ
145 select SYSCTL_EXCEPTION_TRACE
146 select THREAD_INFO_IN_TASK
147 help
148 ARM 64-bit (AArch64) Linux support.
149
150config 64BIT
151 def_bool y
152
153config ARCH_PHYS_ADDR_T_64BIT
154 def_bool y
155
156config MMU
157 def_bool y
158
159config ARM64_PAGE_SHIFT
160 int
161 default 16 if ARM64_64K_PAGES
162 default 14 if ARM64_16K_PAGES
163 default 12
164
165config ARM64_CONT_SHIFT
166 int
167 default 5 if ARM64_64K_PAGES
168 default 7 if ARM64_16K_PAGES
169 default 4
170
171config ARCH_MMAP_RND_BITS_MIN
172 default 14 if ARM64_64K_PAGES
173 default 16 if ARM64_16K_PAGES
174 default 18
175
176# max bits determined by the following formula:
177# VA_BITS - PAGE_SHIFT - 3
178config ARCH_MMAP_RND_BITS_MAX
179 default 19 if ARM64_VA_BITS=36
180 default 24 if ARM64_VA_BITS=39
181 default 27 if ARM64_VA_BITS=42
182 default 30 if ARM64_VA_BITS=47
183 default 29 if ARM64_VA_BITS=48 && ARM64_64K_PAGES
184 default 31 if ARM64_VA_BITS=48 && ARM64_16K_PAGES
185 default 33 if ARM64_VA_BITS=48
186 default 14 if ARM64_64K_PAGES
187 default 16 if ARM64_16K_PAGES
188 default 18
189
190config ARCH_MMAP_RND_COMPAT_BITS_MIN
191 default 7 if ARM64_64K_PAGES
192 default 9 if ARM64_16K_PAGES
193 default 11
194
195config ARCH_MMAP_RND_COMPAT_BITS_MAX
196 default 16
197
198config NO_IOPORT_MAP
199 def_bool y if !PCI
200
201config STACKTRACE_SUPPORT
202 def_bool y
203
204config ILLEGAL_POINTER_VALUE
205 hex
206 default 0xdead000000000000
207
208config LOCKDEP_SUPPORT
209 def_bool y
210
211config TRACE_IRQFLAGS_SUPPORT
212 def_bool y
213
214config RWSEM_XCHGADD_ALGORITHM
215 def_bool y
216
217config GENERIC_BUG
218 def_bool y
219 depends on BUG
220
221config GENERIC_BUG_RELATIVE_POINTERS
222 def_bool y
223 depends on GENERIC_BUG
224
225config GENERIC_HWEIGHT
226 def_bool y
227
228config GENERIC_CSUM
229 def_bool y
230
231config GENERIC_CALIBRATE_DELAY
232 def_bool y
233
234config ZONE_DMA32
235 def_bool y
236
237config HAVE_GENERIC_GUP
238 def_bool y
239
240config ARCH_DMA_ADDR_T_64BIT
241 def_bool y
242
243config NEED_DMA_MAP_STATE
244 def_bool y
245
246config NEED_SG_DMA_LENGTH
247 def_bool y
248
249config SMP
250 def_bool y
251
252config SWIOTLB
253 def_bool y
254
255config IOMMU_HELPER
256 def_bool SWIOTLB
257
258config KERNEL_MODE_NEON
259 def_bool y
260
261config FIX_EARLYCON_MEM
262 def_bool y
263
264config PGTABLE_LEVELS
265 int
266 default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36
267 default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42
268 default 3 if ARM64_64K_PAGES && ARM64_VA_BITS_48
269 default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39
270 default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47
271 default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48
272
273config ARCH_SUPPORTS_UPROBES
274 def_bool y
275
276config ARCH_PROC_KCORE_TEXT
277 def_bool y
278
279config MULTI_IRQ_HANDLER
280 def_bool y
281
282source "init/Kconfig"
283
284source "kernel/Kconfig.freezer"
285
286source "arch/arm64/Kconfig.platforms"
287
288menu "Bus support"
289
290config PCI
291 bool "PCI support"
292 help
293 This feature enables support for PCI bus system. If you say Y
294 here, the kernel will include drivers and infrastructure code
295 to support PCI bus devices.
296
297config PCI_DOMAINS
298 def_bool PCI
299
300config PCI_DOMAINS_GENERIC
301 def_bool PCI
302
303config PCI_SYSCALL
304 def_bool PCI
305
306source "drivers/pci/Kconfig"
307
308endmenu
309
310menu "Kernel Features"
311
312menu "ARM errata workarounds via the alternatives framework"
313
314config ARM64_ERRATUM_826319
315 bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted"
316 default y
317 help
318 This option adds an alternative code sequence to work around ARM
319 erratum 826319 on Cortex-A53 parts up to r0p2 with an AMBA 4 ACE or
320 AXI master interface and an L2 cache.
321
322 If a Cortex-A53 uses an AMBA AXI4 ACE interface to other processors
323 and is unable to accept a certain write via this interface, it will
324 not progress on read data presented on the read data channel and the
325 system can deadlock.
326
327 The workaround promotes data cache clean instructions to
328 data cache clean-and-invalidate.
329 Please note that this does not necessarily enable the workaround,
330 as it depends on the alternative framework, which will only patch
331 the kernel if an affected CPU is detected.
332
333 If unsure, say Y.
334
335config ARM64_ERRATUM_827319
336 bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect"
337 default y
338 help
339 This option adds an alternative code sequence to work around ARM
340 erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI
341 master interface and an L2 cache.
342
343 Under certain conditions this erratum can cause a clean line eviction
344 to occur at the same time as another transaction to the same address
345 on the AMBA 5 CHI interface, which can cause data corruption if the
346 interconnect reorders the two transactions.
347
348 The workaround promotes data cache clean instructions to
349 data cache clean-and-invalidate.
350 Please note that this does not necessarily enable the workaround,
351 as it depends on the alternative framework, which will only patch
352 the kernel if an affected CPU is detected.
353
354 If unsure, say Y.
355
356config ARM64_ERRATUM_824069
357 bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop"
358 default y
359 help
360 This option adds an alternative code sequence to work around ARM
361 erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected
362 to a coherent interconnect.
363
364 If a Cortex-A53 processor is executing a store or prefetch for
365 write instruction at the same time as a processor in another
366 cluster is executing a cache maintenance operation to the same
367 address, then this erratum might cause a clean cache line to be
368 incorrectly marked as dirty.
369
370 The workaround promotes data cache clean instructions to
371 data cache clean-and-invalidate.
372 Please note that this option does not necessarily enable the
373 workaround, as it depends on the alternative framework, which will
374 only patch the kernel if an affected CPU is detected.
375
376 If unsure, say Y.
377
378config ARM64_ERRATUM_819472
379 bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption"
380 default y
381 help
382 This option adds an alternative code sequence to work around ARM
383 erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache
384 present when it is connected to a coherent interconnect.
385
386 If the processor is executing a load and store exclusive sequence at
387 the same time as a processor in another cluster is executing a cache
388 maintenance operation to the same address, then this erratum might
389 cause data corruption.
390
391 The workaround promotes data cache clean instructions to
392 data cache clean-and-invalidate.
393 Please note that this does not necessarily enable the workaround,
394 as it depends on the alternative framework, which will only patch
395 the kernel if an affected CPU is detected.
396
397 If unsure, say Y.
398
399config ARM64_ERRATUM_832075
400 bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads"
401 default y
402 help
403 This option adds an alternative code sequence to work around ARM
404 erratum 832075 on Cortex-A57 parts up to r1p2.
405
406 Affected Cortex-A57 parts might deadlock when exclusive load/store
407 instructions to Write-Back memory are mixed with Device loads.
408
409 The workaround is to promote device loads to use Load-Acquire
410 semantics.
411 Please note that this does not necessarily enable the workaround,
412 as it depends on the alternative framework, which will only patch
413 the kernel if an affected CPU is detected.
414
415 If unsure, say Y.
416
417config ARM64_ERRATUM_834220
418 bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault"
419 depends on KVM
420 default y
421 help
422 This option adds an alternative code sequence to work around ARM
423 erratum 834220 on Cortex-A57 parts up to r1p2.
424
425 Affected Cortex-A57 parts might report a Stage 2 translation
426 fault as the result of a Stage 1 fault for load crossing a
427 page boundary when there is a permission or device memory
428 alignment fault at Stage 1 and a translation fault at Stage 2.
429
430 The workaround is to verify that the Stage 1 translation
431 doesn't generate a fault before handling the Stage 2 fault.
432 Please note that this does not necessarily enable the workaround,
433 as it depends on the alternative framework, which will only patch
434 the kernel if an affected CPU is detected.
435
436 If unsure, say Y.
437
438config ARM64_ERRATUM_845719
439 bool "Cortex-A53: 845719: a load might read incorrect data"
440 depends on COMPAT
441 default y
442 help
443 This option adds an alternative code sequence to work around ARM
444 erratum 845719 on Cortex-A53 parts up to r0p4.
445
446 When running a compat (AArch32) userspace on an affected Cortex-A53
447 part, a load at EL0 from a virtual address that matches the bottom 32
448 bits of the virtual address used by a recent load at (AArch64) EL1
449 might return incorrect data.
450
451 The workaround is to write the contextidr_el1 register on exception
452 return to a 32-bit task.
453 Please note that this does not necessarily enable the workaround,
454 as it depends on the alternative framework, which will only patch
455 the kernel if an affected CPU is detected.
456
457 If unsure, say Y.
458
459config ARM64_ERRATUM_843419
460 bool "Cortex-A53: 843419: A load or store might access an incorrect address"
461 default y
462 select ARM64_MODULE_PLTS if MODULES
463 help
464 This option links the kernel with '--fix-cortex-a53-843419' and
465 enables PLT support to replace certain ADRP instructions, which can
466 cause subsequent memory accesses to use an incorrect address on
467 Cortex-A53 parts up to r0p4.
468
469 If unsure, say Y.
470
471config ARM64_ERRATUM_1024718
472 bool "Cortex-A55: 1024718: Update of DBM/AP bits without break before make might result in incorrect update"
473 default y
474 help
475 This option adds work around for Arm Cortex-A55 Erratum 1024718.
476
477 Affected Cortex-A55 cores (r0p0, r0p1, r1p0) could cause incorrect
478 update of the hardware dirty bit when the DBM/AP bits are updated
479 without a break-before-make. The work around is to disable the usage
480 of hardware DBM locally on the affected cores. CPUs not affected by
481 erratum will continue to use the feature.
482
483 If unsure, say Y.
484
485config CAVIUM_ERRATUM_22375
486 bool "Cavium erratum 22375, 24313"
487 default y
488 help
489 Enable workaround for erratum 22375, 24313.
490
491 This implements two gicv3-its errata workarounds for ThunderX. Both
492 with small impact affecting only ITS table allocation.
493
494 erratum 22375: only alloc 8MB table size
495 erratum 24313: ignore memory access type
496
497 The fixes are in ITS initialization and basically ignore memory access
498 type and table size provided by the TYPER and BASER registers.
499
500 If unsure, say Y.
501
502config CAVIUM_ERRATUM_23144
503 bool "Cavium erratum 23144: ITS SYNC hang on dual socket system"
504 depends on NUMA
505 default y
506 help
507 ITS SYNC command hang for cross node io and collections/cpu mapping.
508
509 If unsure, say Y.
510
511config CAVIUM_ERRATUM_23154
512 bool "Cavium erratum 23154: Access to ICC_IAR1_EL1 is not sync'ed"
513 default y
514 help
515 The gicv3 of ThunderX requires a modified version for
516 reading the IAR status to ensure data synchronization
517 (access to icc_iar1_el1 is not sync'ed before and after).
518
519 If unsure, say Y.
520
521config CAVIUM_ERRATUM_27456
522 bool "Cavium erratum 27456: Broadcast TLBI instructions may cause icache corruption"
523 default y
524 help
525 On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI
526 instructions may cause the icache to become corrupted if it
527 contains data for a non-current ASID. The fix is to
528 invalidate the icache when changing the mm context.
529
530 If unsure, say Y.
531
532config CAVIUM_ERRATUM_30115
533 bool "Cavium erratum 30115: Guest may disable interrupts in host"
534 default y
535 help
536 On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through
537 1.2, and T83 Pass 1.0, KVM guest execution may disable
538 interrupts in host. Trapping both GICv3 group-0 and group-1
539 accesses sidesteps the issue.
540
541 If unsure, say Y.
542
543config QCOM_FALKOR_ERRATUM_1003
544 bool "Falkor E1003: Incorrect translation due to ASID change"
545 default y
546 help
547 On Falkor v1, an incorrect ASID may be cached in the TLB when ASID
548 and BADDR are changed together in TTBRx_EL1. Since we keep the ASID
549 in TTBR1_EL1, this situation only occurs in the entry trampoline and
550 then only for entries in the walk cache, since the leaf translation
551 is unchanged. Work around the erratum by invalidating the walk cache
552 entries for the trampoline before entering the kernel proper.
553
554config QCOM_FALKOR_ERRATUM_1009
555 bool "Falkor E1009: Prematurely complete a DSB after a TLBI"
556 default y
557 help
558 On Falkor v1, the CPU may prematurely complete a DSB following a
559 TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation
560 one more time to fix the issue.
561
562 If unsure, say Y.
563
564config QCOM_QDF2400_ERRATUM_0065
565 bool "QDF2400 E0065: Incorrect GITS_TYPER.ITT_Entry_size"
566 default y
567 help
568 On Qualcomm Datacenter Technologies QDF2400 SoC, ITS hardware reports
569 ITE size incorrectly. The GITS_TYPER.ITT_Entry_size field should have
570 been indicated as 16Bytes (0xf), not 8Bytes (0x7).
571
572 If unsure, say Y.
573
574config SOCIONEXT_SYNQUACER_PREITS
575 bool "Socionext Synquacer: Workaround for GICv3 pre-ITS"
576 default y
577 help
578 Socionext Synquacer SoCs implement a separate h/w block to generate
579 MSI doorbell writes with non-zero values for the device ID.
580
581 If unsure, say Y.
582
583config HISILICON_ERRATUM_161600802
584 bool "Hip07 161600802: Erroneous redistributor VLPI base"
585 default y
586 help
587 The HiSilicon Hip07 SoC usees the wrong redistributor base
588 when issued ITS commands such as VMOVP and VMAPP, and requires
589 a 128kB offset to be applied to the target address in this commands.
590
591 If unsure, say Y.
592
593config QCOM_FALKOR_ERRATUM_E1041
594 bool "Falkor E1041: Speculative instruction fetches might cause errant memory access"
595 default y
596 help
597 Falkor CPU may speculatively fetch instructions from an improper
598 memory location when MMU translation is changed from SCTLR_ELn[M]=1
599 to SCTLR_ELn[M]=0. Prefix an ISB instruction to fix the problem.
600
601 If unsure, say Y.
602
603endmenu
604
605
606choice
607 prompt "Page size"
608 default ARM64_4K_PAGES
609 help
610 Page size (translation granule) configuration.
611
612config ARM64_4K_PAGES
613 bool "4KB"
614 help
615 This feature enables 4KB pages support.
616
617config ARM64_16K_PAGES
618 bool "16KB"
619 help
620 The system will use 16KB pages support. AArch32 emulation
621 requires applications compiled with 16K (or a multiple of 16K)
622 aligned segments.
623
624config ARM64_64K_PAGES
625 bool "64KB"
626 help
627 This feature enables 64KB pages support (4KB by default)
628 allowing only two levels of page tables and faster TLB
629 look-up. AArch32 emulation requires applications compiled
630 with 64K aligned segments.
631
632endchoice
633
634choice
635 prompt "Virtual address space size"
636 default ARM64_VA_BITS_39 if ARM64_4K_PAGES
637 default ARM64_VA_BITS_47 if ARM64_16K_PAGES
638 default ARM64_VA_BITS_42 if ARM64_64K_PAGES
639 help
640 Allows choosing one of multiple possible virtual address
641 space sizes. The level of translation table is determined by
642 a combination of page size and virtual address space size.
643
644config ARM64_VA_BITS_36
645 bool "36-bit" if EXPERT
646 depends on ARM64_16K_PAGES
647
648config ARM64_VA_BITS_39
649 bool "39-bit"
650 depends on ARM64_4K_PAGES
651
652config ARM64_VA_BITS_42
653 bool "42-bit"
654 depends on ARM64_64K_PAGES
655
656config ARM64_VA_BITS_47
657 bool "47-bit"
658 depends on ARM64_16K_PAGES
659
660config ARM64_VA_BITS_48
661 bool "48-bit"
662
663endchoice
664
665config ARM64_VA_BITS
666 int
667 default 36 if ARM64_VA_BITS_36
668 default 39 if ARM64_VA_BITS_39
669 default 42 if ARM64_VA_BITS_42
670 default 47 if ARM64_VA_BITS_47
671 default 48 if ARM64_VA_BITS_48
672
673choice
674 prompt "Physical address space size"
675 default ARM64_PA_BITS_48
676 help
677 Choose the maximum physical address range that the kernel will
678 support.
679
680config ARM64_PA_BITS_48
681 bool "48-bit"
682
683config ARM64_PA_BITS_52
684 bool "52-bit (ARMv8.2)"
685 depends on ARM64_64K_PAGES
686 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
687 help
688 Enable support for a 52-bit physical address space, introduced as
689 part of the ARMv8.2-LPA extension.
690
691 With this enabled, the kernel will also continue to work on CPUs that
692 do not support ARMv8.2-LPA, but with some added memory overhead (and
693 minor performance overhead).
694
695endchoice
696
697config ARM64_PA_BITS
698 int
699 default 48 if ARM64_PA_BITS_48
700 default 52 if ARM64_PA_BITS_52
701
702config CPU_BIG_ENDIAN
703 bool "Build big-endian kernel"
704 help
705 Say Y if you plan on running a kernel in big-endian mode.
706
707config SCHED_MC
708 bool "Multi-core scheduler support"
709 help
710 Multi-core scheduler support improves the CPU scheduler's decision
711 making when dealing with multi-core CPU chips at a cost of slightly
712 increased overhead in some places. If unsure say N here.
713
714config SCHED_SMT
715 bool "SMT scheduler support"
716 help
717 Improves the CPU scheduler's decision making when dealing with
718 MultiThreading at a cost of slightly increased overhead in some
719 places. If unsure say N here.
720
721config NR_CPUS
722 int "Maximum number of CPUs (2-4096)"
723 range 2 4096
724 # These have to remain sorted largest to smallest
725 default "64"
726
727config HOTPLUG_CPU
728 bool "Support for hot-pluggable CPUs"
729 select GENERIC_IRQ_MIGRATION
730 help
731 Say Y here to experiment with turning CPUs off and on. CPUs
732 can be controlled through /sys/devices/system/cpu.
733
734# Common NUMA Features
735config NUMA
736 bool "Numa Memory Allocation and Scheduler Support"
737 select ACPI_NUMA if ACPI
738 select OF_NUMA
739 help
740 Enable NUMA (Non Uniform Memory Access) support.
741
742 The kernel will try to allocate memory used by a CPU on the
743 local memory of the CPU and add some more
744 NUMA awareness to the kernel.
745
746config NODES_SHIFT
747 int "Maximum NUMA Nodes (as a power of 2)"
748 range 1 10
749 default "2"
750 depends on NEED_MULTIPLE_NODES
751 help
752 Specify the maximum number of NUMA Nodes available on the target
753 system. Increases memory reserved to accommodate various tables.
754
755config USE_PERCPU_NUMA_NODE_ID
756 def_bool y
757 depends on NUMA
758
759config HAVE_SETUP_PER_CPU_AREA
760 def_bool y
761 depends on NUMA
762
763config NEED_PER_CPU_EMBED_FIRST_CHUNK
764 def_bool y
765 depends on NUMA
766
767config HOLES_IN_ZONE
768 def_bool y
769 depends on NUMA
770
771source kernel/Kconfig.preempt
772source kernel/Kconfig.hz
773
774config ARCH_SUPPORTS_DEBUG_PAGEALLOC
775 def_bool y
776
777config ARCH_HAS_HOLES_MEMORYMODEL
778 def_bool y if SPARSEMEM
779
780config ARCH_SPARSEMEM_ENABLE
781 def_bool y
782 select SPARSEMEM_VMEMMAP_ENABLE
783
784config ARCH_SPARSEMEM_DEFAULT
785 def_bool ARCH_SPARSEMEM_ENABLE
786
787config ARCH_SELECT_MEMORY_MODEL
788 def_bool ARCH_SPARSEMEM_ENABLE
789
790config HAVE_ARCH_PFN_VALID
791 def_bool ARCH_HAS_HOLES_MEMORYMODEL || !SPARSEMEM
792
793config HW_PERF_EVENTS
794 def_bool y
795 depends on ARM_PMU
796
797config SYS_SUPPORTS_HUGETLBFS
798 def_bool y
799
800config ARCH_WANT_HUGE_PMD_SHARE
801 def_bool y if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
802
803config ARCH_HAS_CACHE_LINE_SIZE
804 def_bool y
805
806source "mm/Kconfig"
807
808config SECCOMP
809 bool "Enable seccomp to safely compute untrusted bytecode"
810 ---help---
811 This kernel feature is useful for number crunching applications
812 that may need to compute untrusted bytecode during their
813 execution. By using pipes or other transports made available to
814 the process as file descriptors supporting the read/write
815 syscalls, it's possible to isolate those applications in
816 their own address space using seccomp. Once seccomp is
817 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
818 and the task is only allowed to execute a few safe syscalls
819 defined by each seccomp mode.
820
821config PARAVIRT
822 bool "Enable paravirtualization code"
823 help
824 This changes the kernel so it can modify itself when it is run
825 under a hypervisor, potentially improving performance significantly
826 over full virtualization.
827
828config PARAVIRT_TIME_ACCOUNTING
829 bool "Paravirtual steal time accounting"
830 select PARAVIRT
831 default n
832 help
833 Select this option to enable fine granularity task steal time
834 accounting. Time spent executing other tasks in parallel with
835 the current vCPU is discounted from the vCPU power. To account for
836 that, there can be a small performance impact.
837
838 If in doubt, say N here.
839
840config KEXEC
841 depends on PM_SLEEP_SMP
842 select KEXEC_CORE
843 bool "kexec system call"
844 ---help---
845 kexec is a system call that implements the ability to shutdown your
846 current kernel, and to start another kernel. It is like a reboot
847 but it is independent of the system firmware. And like a reboot
848 you can start any kernel with it, not just Linux.
849
850config CRASH_DUMP
851 bool "Build kdump crash kernel"
852 help
853 Generate crash dump after being started by kexec. This should
854 be normally only set in special crash dump kernels which are
855 loaded in the main kernel with kexec-tools into a specially
856 reserved region and then later executed after a crash by
857 kdump/kexec.
858
859 For more details see Documentation/kdump/kdump.txt
860
861config XEN_DOM0
862 def_bool y
863 depends on XEN
864
865config XEN
866 bool "Xen guest support on ARM64"
867 depends on ARM64 && OF
868 select SWIOTLB_XEN
869 select PARAVIRT
870 help
871 Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64.
872
873config FORCE_MAX_ZONEORDER
874 int
875 default "14" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE)
876 default "12" if (ARM64_16K_PAGES && TRANSPARENT_HUGEPAGE)
877 default "11"
878 help
879 The kernel memory allocator divides physically contiguous memory
880 blocks into "zones", where each zone is a power of two number of
881 pages. This option selects the largest power of two that the kernel
882 keeps in the memory allocator. If you need to allocate very large
883 blocks of physically contiguous memory, then you may need to
884 increase this value.
885
886 This config option is actually maximum order plus one. For example,
887 a value of 11 means that the largest free memory block is 2^10 pages.
888
889 We make sure that we can allocate upto a HugePage size for each configuration.
890 Hence we have :
891 MAX_ORDER = (PMD_SHIFT - PAGE_SHIFT) + 1 => PAGE_SHIFT - 2
892
893 However for 4K, we choose a higher default value, 11 as opposed to 10, giving us
894 4M allocations matching the default size used by generic code.
895
896config UNMAP_KERNEL_AT_EL0
897 bool "Unmap kernel when running in userspace (aka \"KAISER\")" if EXPERT
898 default y
899 help
900 Speculation attacks against some high-performance processors can
901 be used to bypass MMU permission checks and leak kernel data to
902 userspace. This can be defended against by unmapping the kernel
903 when running in userspace, mapping it back in on exception entry
904 via a trampoline page in the vector table.
905
906 If unsure, say Y.
907
908config HARDEN_BRANCH_PREDICTOR
909 bool "Harden the branch predictor against aliasing attacks" if EXPERT
910 default y
911 help
912 Speculation attacks against some high-performance processors rely on
913 being able to manipulate the branch predictor for a victim context by
914 executing aliasing branches in the attacker context. Such attacks
915 can be partially mitigated against by clearing internal branch
916 predictor state and limiting the prediction logic in some situations.
917
918 This config option will take CPU-specific actions to harden the
919 branch predictor against aliasing attacks and may rely on specific
920 instruction sequences or control bits being set by the system
921 firmware.
922
923 If unsure, say Y.
924
925config HARDEN_EL2_VECTORS
926 bool "Harden EL2 vector mapping against system register leak" if EXPERT
927 default y
928 help
929 Speculation attacks against some high-performance processors can
930 be used to leak privileged information such as the vector base
931 register, resulting in a potential defeat of the EL2 layout
932 randomization.
933
934 This config option will map the vectors to a fixed location,
935 independent of the EL2 code mapping, so that revealing VBAR_EL2
936 to an attacker does not give away any extra information. This
937 only gets enabled on affected CPUs.
938
939 If unsure, say Y.
940
941menuconfig ARMV8_DEPRECATED
942 bool "Emulate deprecated/obsolete ARMv8 instructions"
943 depends on COMPAT
944 depends on SYSCTL
945 help
946 Legacy software support may require certain instructions
947 that have been deprecated or obsoleted in the architecture.
948
949 Enable this config to enable selective emulation of these
950 features.
951
952 If unsure, say Y
953
954if ARMV8_DEPRECATED
955
956config SWP_EMULATION
957 bool "Emulate SWP/SWPB instructions"
958 help
959 ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that
960 they are always undefined. Say Y here to enable software
961 emulation of these instructions for userspace using LDXR/STXR.
962
963 In some older versions of glibc [<=2.8] SWP is used during futex
964 trylock() operations with the assumption that the code will not
965 be preempted. This invalid assumption may be more likely to fail
966 with SWP emulation enabled, leading to deadlock of the user
967 application.
968
969 NOTE: when accessing uncached shared regions, LDXR/STXR rely
970 on an external transaction monitoring block called a global
971 monitor to maintain update atomicity. If your system does not
972 implement a global monitor, this option can cause programs that
973 perform SWP operations to uncached memory to deadlock.
974
975 If unsure, say Y
976
977config CP15_BARRIER_EMULATION
978 bool "Emulate CP15 Barrier instructions"
979 help
980 The CP15 barrier instructions - CP15ISB, CP15DSB, and
981 CP15DMB - are deprecated in ARMv8 (and ARMv7). It is
982 strongly recommended to use the ISB, DSB, and DMB
983 instructions instead.
984
985 Say Y here to enable software emulation of these
986 instructions for AArch32 userspace code. When this option is
987 enabled, CP15 barrier usage is traced which can help
988 identify software that needs updating.
989
990 If unsure, say Y
991
992config SETEND_EMULATION
993 bool "Emulate SETEND instruction"
994 help
995 The SETEND instruction alters the data-endianness of the
996 AArch32 EL0, and is deprecated in ARMv8.
997
998 Say Y here to enable software emulation of the instruction
999 for AArch32 userspace code.
1000
1001 Note: All the cpus on the system must have mixed endian support at EL0
1002 for this feature to be enabled. If a new CPU - which doesn't support mixed
1003 endian - is hotplugged in after this feature has been enabled, there could
1004 be unexpected results in the applications.
1005
1006 If unsure, say Y
1007endif
1008
1009config ARM64_SW_TTBR0_PAN
1010 bool "Emulate Privileged Access Never using TTBR0_EL1 switching"
1011 help
1012 Enabling this option prevents the kernel from accessing
1013 user-space memory directly by pointing TTBR0_EL1 to a reserved
1014 zeroed area and reserved ASID. The user access routines
1015 restore the valid TTBR0_EL1 temporarily.
1016
1017menu "ARMv8.1 architectural features"
1018
1019config ARM64_HW_AFDBM
1020 bool "Support for hardware updates of the Access and Dirty page flags"
1021 default y
1022 help
1023 The ARMv8.1 architecture extensions introduce support for
1024 hardware updates of the access and dirty information in page
1025 table entries. When enabled in TCR_EL1 (HA and HD bits) on
1026 capable processors, accesses to pages with PTE_AF cleared will
1027 set this bit instead of raising an access flag fault.
1028 Similarly, writes to read-only pages with the DBM bit set will
1029 clear the read-only bit (AP[2]) instead of raising a
1030 permission fault.
1031
1032 Kernels built with this configuration option enabled continue
1033 to work on pre-ARMv8.1 hardware and the performance impact is
1034 minimal. If unsure, say Y.
1035
1036config ARM64_PAN
1037 bool "Enable support for Privileged Access Never (PAN)"
1038 default y
1039 help
1040 Privileged Access Never (PAN; part of the ARMv8.1 Extensions)
1041 prevents the kernel or hypervisor from accessing user-space (EL0)
1042 memory directly.
1043
1044 Choosing this option will cause any unprotected (not using
1045 copy_to_user et al) memory access to fail with a permission fault.
1046
1047 The feature is detected at runtime, and will remain as a 'nop'
1048 instruction if the cpu does not implement the feature.
1049
1050config ARM64_LSE_ATOMICS
1051 bool "Atomic instructions"
1052 help
1053 As part of the Large System Extensions, ARMv8.1 introduces new
1054 atomic instructions that are designed specifically to scale in
1055 very large systems.
1056
1057 Say Y here to make use of these instructions for the in-kernel
1058 atomic routines. This incurs a small overhead on CPUs that do
1059 not support these instructions and requires the kernel to be
1060 built with binutils >= 2.25.
1061
1062config ARM64_VHE
1063 bool "Enable support for Virtualization Host Extensions (VHE)"
1064 default y
1065 help
1066 Virtualization Host Extensions (VHE) allow the kernel to run
1067 directly at EL2 (instead of EL1) on processors that support
1068 it. This leads to better performance for KVM, as they reduce
1069 the cost of the world switch.
1070
1071 Selecting this option allows the VHE feature to be detected
1072 at runtime, and does not affect processors that do not
1073 implement this feature.
1074
1075endmenu
1076
1077menu "ARMv8.2 architectural features"
1078
1079config ARM64_UAO
1080 bool "Enable support for User Access Override (UAO)"
1081 default y
1082 help
1083 User Access Override (UAO; part of the ARMv8.2 Extensions)
1084 causes the 'unprivileged' variant of the load/store instructions to
1085 be overridden to be privileged.
1086
1087 This option changes get_user() and friends to use the 'unprivileged'
1088 variant of the load/store instructions. This ensures that user-space
1089 really did have access to the supplied memory. When addr_limit is
1090 set to kernel memory the UAO bit will be set, allowing privileged
1091 access to kernel memory.
1092
1093 Choosing this option will cause copy_to_user() et al to use user-space
1094 memory permissions.
1095
1096 The feature is detected at runtime, the kernel will use the
1097 regular load/store instructions if the cpu does not implement the
1098 feature.
1099
1100config ARM64_PMEM
1101 bool "Enable support for persistent memory"
1102 select ARCH_HAS_PMEM_API
1103 select ARCH_HAS_UACCESS_FLUSHCACHE
1104 help
1105 Say Y to enable support for the persistent memory API based on the
1106 ARMv8.2 DCPoP feature.
1107
1108 The feature is detected at runtime, and the kernel will use DC CVAC
1109 operations if DC CVAP is not supported (following the behaviour of
1110 DC CVAP itself if the system does not define a point of persistence).
1111
1112config ARM64_RAS_EXTN
1113 bool "Enable support for RAS CPU Extensions"
1114 default y
1115 help
1116 CPUs that support the Reliability, Availability and Serviceability
1117 (RAS) Extensions, part of ARMv8.2 are able to track faults and
1118 errors, classify them and report them to software.
1119
1120 On CPUs with these extensions system software can use additional
1121 barriers to determine if faults are pending and read the
1122 classification from a new set of registers.
1123
1124 Selecting this feature will allow the kernel to use these barriers
1125 and access the new registers if the system supports the extension.
1126 Platform RAS features may additionally depend on firmware support.
1127
1128endmenu
1129
1130config ARM64_SVE
1131 bool "ARM Scalable Vector Extension support"
1132 default y
1133 help
1134 The Scalable Vector Extension (SVE) is an extension to the AArch64
1135 execution state which complements and extends the SIMD functionality
1136 of the base architecture to support much larger vectors and to enable
1137 additional vectorisation opportunities.
1138
1139 To enable use of this extension on CPUs that implement it, say Y.
1140
1141 Note that for architectural reasons, firmware _must_ implement SVE
1142 support when running on SVE capable hardware. The required support
1143 is present in:
1144
1145 * version 1.5 and later of the ARM Trusted Firmware
1146 * the AArch64 boot wrapper since commit 5e1261e08abf
1147 ("bootwrapper: SVE: Enable SVE for EL2 and below").
1148
1149 For other firmware implementations, consult the firmware documentation
1150 or vendor.
1151
1152 If you need the kernel to boot on SVE-capable hardware with broken
1153 firmware, you may need to say N here until you get your firmware
1154 fixed. Otherwise, you may experience firmware panics or lockups when
1155 booting the kernel. If unsure and you are not observing these
1156 symptoms, you should assume that it is safe to say Y.
1157
1158config ARM64_MODULE_PLTS
1159 bool
1160 select HAVE_MOD_ARCH_SPECIFIC
1161
1162config RELOCATABLE
1163 bool
1164 help
1165 This builds the kernel as a Position Independent Executable (PIE),
1166 which retains all relocation metadata required to relocate the
1167 kernel binary at runtime to a different virtual address than the
1168 address it was linked at.
1169 Since AArch64 uses the RELA relocation format, this requires a
1170 relocation pass at runtime even if the kernel is loaded at the
1171 same address it was linked at.
1172
1173config RANDOMIZE_BASE
1174 bool "Randomize the address of the kernel image"
1175 select ARM64_MODULE_PLTS if MODULES
1176 select RELOCATABLE
1177 help
1178 Randomizes the virtual address at which the kernel image is
1179 loaded, as a security feature that deters exploit attempts
1180 relying on knowledge of the location of kernel internals.
1181
1182 It is the bootloader's job to provide entropy, by passing a
1183 random u64 value in /chosen/kaslr-seed at kernel entry.
1184
1185 When booting via the UEFI stub, it will invoke the firmware's
1186 EFI_RNG_PROTOCOL implementation (if available) to supply entropy
1187 to the kernel proper. In addition, it will randomise the physical
1188 location of the kernel Image as well.
1189
1190 If unsure, say N.
1191
1192config RANDOMIZE_MODULE_REGION_FULL
1193 bool "Randomize the module region over a 4 GB range"
1194 depends on RANDOMIZE_BASE
1195 default y
1196 help
1197 Randomizes the location of the module region inside a 4 GB window
1198 covering the core kernel. This way, it is less likely for modules
1199 to leak information about the location of core kernel data structures
1200 but it does imply that function calls between modules and the core
1201 kernel will need to be resolved via veneers in the module PLT.
1202
1203 When this option is not set, the module region will be randomized over
1204 a limited range that contains the [_stext, _etext] interval of the
1205 core kernel, so branch relocations are always in range.
1206
1207endmenu
1208
1209menu "Boot options"
1210
1211config ARM64_ACPI_PARKING_PROTOCOL
1212 bool "Enable support for the ARM64 ACPI parking protocol"
1213 depends on ACPI
1214 help
1215 Enable support for the ARM64 ACPI parking protocol. If disabled
1216 the kernel will not allow booting through the ARM64 ACPI parking
1217 protocol even if the corresponding data is present in the ACPI
1218 MADT table.
1219
1220config CMDLINE
1221 string "Default kernel command string"
1222 default ""
1223 help
1224 Provide a set of default command-line options at build time by
1225 entering them here. As a minimum, you should specify the the
1226 root device (e.g. root=/dev/nfs).
1227
1228config CMDLINE_FORCE
1229 bool "Always use the default kernel command string"
1230 help
1231 Always use the default kernel command string, even if the boot
1232 loader passes other arguments to the kernel.
1233 This is useful if you cannot or don't want to change the
1234 command-line options your boot loader passes to the kernel.
1235
1236config EFI_STUB
1237 bool
1238
1239config EFI
1240 bool "UEFI runtime support"
1241 depends on OF && !CPU_BIG_ENDIAN
1242 depends on KERNEL_MODE_NEON
1243 select LIBFDT
1244 select UCS2_STRING
1245 select EFI_PARAMS_FROM_FDT
1246 select EFI_RUNTIME_WRAPPERS
1247 select EFI_STUB
1248 select EFI_ARMSTUB
1249 default y
1250 help
1251 This option provides support for runtime services provided
1252 by UEFI firmware (such as non-volatile variables, realtime
1253 clock, and platform reset). A UEFI stub is also provided to
1254 allow the kernel to be booted as an EFI application. This
1255 is only useful on systems that have UEFI firmware.
1256
1257config DMI
1258 bool "Enable support for SMBIOS (DMI) tables"
1259 depends on EFI
1260 default y
1261 help
1262 This enables SMBIOS/DMI feature for systems.
1263
1264 This option is only useful on systems that have UEFI firmware.
1265 However, even with this option, the resultant kernel should
1266 continue to boot on existing non-UEFI platforms.
1267
1268endmenu
1269
1270menu "Userspace binary formats"
1271
1272source "fs/Kconfig.binfmt"
1273
1274config COMPAT
1275 bool "Kernel support for 32-bit EL0"
1276 depends on ARM64_4K_PAGES || EXPERT
1277 select COMPAT_BINFMT_ELF if BINFMT_ELF
1278 select HAVE_UID16
1279 select OLD_SIGSUSPEND3
1280 select COMPAT_OLD_SIGACTION
1281 help
1282 This option enables support for a 32-bit EL0 running under a 64-bit
1283 kernel at EL1. AArch32-specific components such as system calls,
1284 the user helper functions, VFP support and the ptrace interface are
1285 handled appropriately by the kernel.
1286
1287 If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware
1288 that you will only be able to execute AArch32 binaries that were compiled
1289 with page size aligned segments.
1290
1291 If you want to execute 32-bit userspace applications, say Y.
1292
1293config SYSVIPC_COMPAT
1294 def_bool y
1295 depends on COMPAT && SYSVIPC
1296
1297endmenu
1298
1299menu "Power management options"
1300
1301source "kernel/power/Kconfig"
1302
1303config ARCH_HIBERNATION_POSSIBLE
1304 def_bool y
1305 depends on CPU_PM
1306
1307config ARCH_HIBERNATION_HEADER
1308 def_bool y
1309 depends on HIBERNATION
1310
1311config ARCH_SUSPEND_POSSIBLE
1312 def_bool y
1313
1314endmenu
1315
1316menu "CPU Power Management"
1317
1318source "drivers/cpuidle/Kconfig"
1319
1320source "drivers/cpufreq/Kconfig"
1321
1322endmenu
1323
1324source "net/Kconfig"
1325
1326source "drivers/Kconfig"
1327
1328source "drivers/firmware/Kconfig"
1329
1330source "drivers/acpi/Kconfig"
1331
1332source "fs/Kconfig"
1333
1334source "arch/arm64/kvm/Kconfig"
1335
1336source "arch/arm64/Kconfig.debug"
1337
1338source "security/Kconfig"
1339
1340source "crypto/Kconfig"
1341if CRYPTO
1342source "arch/arm64/crypto/Kconfig"
1343endif
1344
1345source "lib/Kconfig"
1# SPDX-License-Identifier: GPL-2.0-only
2config ARM64
3 def_bool y
4 select ACPI_CCA_REQUIRED if ACPI
5 select ACPI_GENERIC_GSI if ACPI
6 select ACPI_GTDT if ACPI
7 select ACPI_IORT if ACPI
8 select ACPI_REDUCED_HARDWARE_ONLY if ACPI
9 select ACPI_MCFG if (ACPI && PCI)
10 select ACPI_SPCR_TABLE if ACPI
11 select ACPI_PPTT if ACPI
12 select ARCH_HAS_DEBUG_WX
13 select ARCH_BINFMT_ELF_STATE
14 select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
15 select ARCH_ENABLE_MEMORY_HOTPLUG
16 select ARCH_ENABLE_MEMORY_HOTREMOVE
17 select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
18 select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
19 select ARCH_HAS_CACHE_LINE_SIZE
20 select ARCH_HAS_DEBUG_VIRTUAL
21 select ARCH_HAS_DEBUG_VM_PGTABLE
22 select ARCH_HAS_DMA_PREP_COHERENT
23 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
24 select ARCH_HAS_FAST_MULTIPLIER
25 select ARCH_HAS_FORTIFY_SOURCE
26 select ARCH_HAS_GCOV_PROFILE_ALL
27 select ARCH_HAS_GIGANTIC_PAGE
28 select ARCH_HAS_KCOV
29 select ARCH_HAS_KEEPINITRD
30 select ARCH_HAS_MEMBARRIER_SYNC_CORE
31 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
32 select ARCH_HAS_PTE_DEVMAP
33 select ARCH_HAS_PTE_SPECIAL
34 select ARCH_HAS_SETUP_DMA_OPS
35 select ARCH_HAS_SET_DIRECT_MAP
36 select ARCH_HAS_SET_MEMORY
37 select ARCH_STACKWALK
38 select ARCH_HAS_STRICT_KERNEL_RWX
39 select ARCH_HAS_STRICT_MODULE_RWX
40 select ARCH_HAS_SYNC_DMA_FOR_DEVICE
41 select ARCH_HAS_SYNC_DMA_FOR_CPU
42 select ARCH_HAS_SYSCALL_WRAPPER
43 select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT
44 select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
45 select ARCH_HAS_ZONE_DMA_SET if EXPERT
46 select ARCH_HAVE_ELF_PROT
47 select ARCH_HAVE_NMI_SAFE_CMPXCHG
48 select ARCH_INLINE_READ_LOCK if !PREEMPTION
49 select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION
50 select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPTION
51 select ARCH_INLINE_READ_LOCK_IRQSAVE if !PREEMPTION
52 select ARCH_INLINE_READ_UNLOCK if !PREEMPTION
53 select ARCH_INLINE_READ_UNLOCK_BH if !PREEMPTION
54 select ARCH_INLINE_READ_UNLOCK_IRQ if !PREEMPTION
55 select ARCH_INLINE_READ_UNLOCK_IRQRESTORE if !PREEMPTION
56 select ARCH_INLINE_WRITE_LOCK if !PREEMPTION
57 select ARCH_INLINE_WRITE_LOCK_BH if !PREEMPTION
58 select ARCH_INLINE_WRITE_LOCK_IRQ if !PREEMPTION
59 select ARCH_INLINE_WRITE_LOCK_IRQSAVE if !PREEMPTION
60 select ARCH_INLINE_WRITE_UNLOCK if !PREEMPTION
61 select ARCH_INLINE_WRITE_UNLOCK_BH if !PREEMPTION
62 select ARCH_INLINE_WRITE_UNLOCK_IRQ if !PREEMPTION
63 select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE if !PREEMPTION
64 select ARCH_INLINE_SPIN_TRYLOCK if !PREEMPTION
65 select ARCH_INLINE_SPIN_TRYLOCK_BH if !PREEMPTION
66 select ARCH_INLINE_SPIN_LOCK if !PREEMPTION
67 select ARCH_INLINE_SPIN_LOCK_BH if !PREEMPTION
68 select ARCH_INLINE_SPIN_LOCK_IRQ if !PREEMPTION
69 select ARCH_INLINE_SPIN_LOCK_IRQSAVE if !PREEMPTION
70 select ARCH_INLINE_SPIN_UNLOCK if !PREEMPTION
71 select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPTION
72 select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPTION
73 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION
74 select ARCH_KEEP_MEMBLOCK
75 select ARCH_USE_CMPXCHG_LOCKREF
76 select ARCH_USE_GNU_PROPERTY
77 select ARCH_USE_MEMTEST
78 select ARCH_USE_QUEUED_RWLOCKS
79 select ARCH_USE_QUEUED_SPINLOCKS
80 select ARCH_USE_SYM_ANNOTATIONS
81 select ARCH_SUPPORTS_DEBUG_PAGEALLOC
82 select ARCH_SUPPORTS_HUGETLBFS
83 select ARCH_SUPPORTS_MEMORY_FAILURE
84 select ARCH_SUPPORTS_SHADOW_CALL_STACK if CC_HAVE_SHADOW_CALL_STACK
85 select ARCH_SUPPORTS_LTO_CLANG if CPU_LITTLE_ENDIAN
86 select ARCH_SUPPORTS_LTO_CLANG_THIN
87 select ARCH_SUPPORTS_CFI_CLANG
88 select ARCH_SUPPORTS_ATOMIC_RMW
89 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && (GCC_VERSION >= 50000 || CC_IS_CLANG)
90 select ARCH_SUPPORTS_NUMA_BALANCING
91 select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT
92 select ARCH_WANT_DEFAULT_BPF_JIT
93 select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
94 select ARCH_WANT_FRAME_POINTERS
95 select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
96 select ARCH_WANT_LD_ORPHAN_WARN
97 select ARCH_WANTS_NO_INSTR
98 select ARCH_HAS_UBSAN_SANITIZE_ALL
99 select ARM_AMBA
100 select ARM_ARCH_TIMER
101 select ARM_GIC
102 select AUDIT_ARCH_COMPAT_GENERIC
103 select ARM_GIC_V2M if PCI
104 select ARM_GIC_V3
105 select ARM_GIC_V3_ITS if PCI
106 select ARM_PSCI_FW
107 select BUILDTIME_TABLE_SORT
108 select CLONE_BACKWARDS
109 select COMMON_CLK
110 select CPU_PM if (SUSPEND || CPU_IDLE)
111 select CRC32
112 select DCACHE_WORD_ACCESS
113 select DMA_DIRECT_REMAP
114 select EDAC_SUPPORT
115 select FRAME_POINTER
116 select GENERIC_ALLOCATOR
117 select GENERIC_ARCH_TOPOLOGY
118 select GENERIC_CLOCKEVENTS_BROADCAST
119 select GENERIC_CPU_AUTOPROBE
120 select GENERIC_CPU_VULNERABILITIES
121 select GENERIC_EARLY_IOREMAP
122 select GENERIC_FIND_FIRST_BIT
123 select GENERIC_IDLE_POLL_SETUP
124 select GENERIC_IRQ_IPI
125 select GENERIC_IRQ_PROBE
126 select GENERIC_IRQ_SHOW
127 select GENERIC_IRQ_SHOW_LEVEL
128 select GENERIC_LIB_DEVMEM_IS_ALLOWED
129 select GENERIC_PCI_IOMAP
130 select GENERIC_PTDUMP
131 select GENERIC_SCHED_CLOCK
132 select GENERIC_SMP_IDLE_THREAD
133 select GENERIC_STRNCPY_FROM_USER
134 select GENERIC_STRNLEN_USER
135 select GENERIC_TIME_VSYSCALL
136 select GENERIC_GETTIMEOFDAY
137 select GENERIC_VDSO_TIME_NS
138 select HANDLE_DOMAIN_IRQ
139 select HARDIRQS_SW_RESEND
140 select HAVE_MOVE_PMD
141 select HAVE_MOVE_PUD
142 select HAVE_PCI
143 select HAVE_ACPI_APEI if (ACPI && EFI)
144 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
145 select HAVE_ARCH_AUDITSYSCALL
146 select HAVE_ARCH_BITREVERSE
147 select HAVE_ARCH_COMPILER_H
148 select HAVE_ARCH_HUGE_VMAP
149 select HAVE_ARCH_JUMP_LABEL
150 select HAVE_ARCH_JUMP_LABEL_RELATIVE
151 select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
152 select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN
153 select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN
154 select HAVE_ARCH_KASAN_HW_TAGS if (HAVE_ARCH_KASAN && ARM64_MTE)
155 select HAVE_ARCH_KFENCE
156 select HAVE_ARCH_KGDB
157 select HAVE_ARCH_MMAP_RND_BITS
158 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
159 select HAVE_ARCH_PFN_VALID
160 select HAVE_ARCH_PREL32_RELOCATIONS
161 select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
162 select HAVE_ARCH_SECCOMP_FILTER
163 select HAVE_ARCH_STACKLEAK
164 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
165 select HAVE_ARCH_TRACEHOOK
166 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
167 select HAVE_ARCH_VMAP_STACK
168 select HAVE_ARM_SMCCC
169 select HAVE_ASM_MODVERSIONS
170 select HAVE_EBPF_JIT
171 select HAVE_C_RECORDMCOUNT
172 select HAVE_CMPXCHG_DOUBLE
173 select HAVE_CMPXCHG_LOCAL
174 select HAVE_CONTEXT_TRACKING
175 select HAVE_DEBUG_KMEMLEAK
176 select HAVE_DMA_CONTIGUOUS
177 select HAVE_DYNAMIC_FTRACE
178 select HAVE_DYNAMIC_FTRACE_WITH_REGS \
179 if $(cc-option,-fpatchable-function-entry=2)
180 select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \
181 if DYNAMIC_FTRACE_WITH_REGS
182 select HAVE_EFFICIENT_UNALIGNED_ACCESS
183 select HAVE_FAST_GUP
184 select HAVE_FTRACE_MCOUNT_RECORD
185 select HAVE_FUNCTION_TRACER
186 select HAVE_FUNCTION_ERROR_INJECTION
187 select HAVE_FUNCTION_GRAPH_TRACER
188 select HAVE_GCC_PLUGINS
189 select HAVE_HW_BREAKPOINT if PERF_EVENTS
190 select HAVE_IRQ_TIME_ACCOUNTING
191 select HAVE_NMI
192 select HAVE_PATA_PLATFORM
193 select HAVE_PERF_EVENTS
194 select HAVE_PERF_REGS
195 select HAVE_PERF_USER_STACK_DUMP
196 select HAVE_REGS_AND_STACK_ACCESS_API
197 select HAVE_FUNCTION_ARG_ACCESS_API
198 select HAVE_FUTEX_CMPXCHG if FUTEX
199 select MMU_GATHER_RCU_TABLE_FREE
200 select HAVE_RSEQ
201 select HAVE_STACKPROTECTOR
202 select HAVE_SYSCALL_TRACEPOINTS
203 select HAVE_KPROBES
204 select HAVE_KRETPROBES
205 select HAVE_GENERIC_VDSO
206 select IOMMU_DMA if IOMMU_SUPPORT
207 select IRQ_DOMAIN
208 select IRQ_FORCED_THREADING
209 select KASAN_VMALLOC if KASAN_GENERIC
210 select MODULES_USE_ELF_RELA
211 select NEED_DMA_MAP_STATE
212 select NEED_SG_DMA_LENGTH
213 select OF
214 select OF_EARLY_FLATTREE
215 select PCI_DOMAINS_GENERIC if PCI
216 select PCI_ECAM if (ACPI && PCI)
217 select PCI_SYSCALL if PCI
218 select POWER_RESET
219 select POWER_SUPPLY
220 select SPARSE_IRQ
221 select SWIOTLB
222 select SYSCTL_EXCEPTION_TRACE
223 select THREAD_INFO_IN_TASK
224 select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD
225 help
226 ARM 64-bit (AArch64) Linux support.
227
228config 64BIT
229 def_bool y
230
231config MMU
232 def_bool y
233
234config ARM64_PAGE_SHIFT
235 int
236 default 16 if ARM64_64K_PAGES
237 default 14 if ARM64_16K_PAGES
238 default 12
239
240config ARM64_CONT_PTE_SHIFT
241 int
242 default 5 if ARM64_64K_PAGES
243 default 7 if ARM64_16K_PAGES
244 default 4
245
246config ARM64_CONT_PMD_SHIFT
247 int
248 default 5 if ARM64_64K_PAGES
249 default 5 if ARM64_16K_PAGES
250 default 4
251
252config ARCH_MMAP_RND_BITS_MIN
253 default 14 if ARM64_64K_PAGES
254 default 16 if ARM64_16K_PAGES
255 default 18
256
257# max bits determined by the following formula:
258# VA_BITS - PAGE_SHIFT - 3
259config ARCH_MMAP_RND_BITS_MAX
260 default 19 if ARM64_VA_BITS=36
261 default 24 if ARM64_VA_BITS=39
262 default 27 if ARM64_VA_BITS=42
263 default 30 if ARM64_VA_BITS=47
264 default 29 if ARM64_VA_BITS=48 && ARM64_64K_PAGES
265 default 31 if ARM64_VA_BITS=48 && ARM64_16K_PAGES
266 default 33 if ARM64_VA_BITS=48
267 default 14 if ARM64_64K_PAGES
268 default 16 if ARM64_16K_PAGES
269 default 18
270
271config ARCH_MMAP_RND_COMPAT_BITS_MIN
272 default 7 if ARM64_64K_PAGES
273 default 9 if ARM64_16K_PAGES
274 default 11
275
276config ARCH_MMAP_RND_COMPAT_BITS_MAX
277 default 16
278
279config NO_IOPORT_MAP
280 def_bool y if !PCI
281
282config STACKTRACE_SUPPORT
283 def_bool y
284
285config ILLEGAL_POINTER_VALUE
286 hex
287 default 0xdead000000000000
288
289config LOCKDEP_SUPPORT
290 def_bool y
291
292config TRACE_IRQFLAGS_SUPPORT
293 def_bool y
294
295config GENERIC_BUG
296 def_bool y
297 depends on BUG
298
299config GENERIC_BUG_RELATIVE_POINTERS
300 def_bool y
301 depends on GENERIC_BUG
302
303config GENERIC_HWEIGHT
304 def_bool y
305
306config GENERIC_CSUM
307 def_bool y
308
309config GENERIC_CALIBRATE_DELAY
310 def_bool y
311
312config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
313 def_bool y
314
315config SMP
316 def_bool y
317
318config KERNEL_MODE_NEON
319 def_bool y
320
321config FIX_EARLYCON_MEM
322 def_bool y
323
324config PGTABLE_LEVELS
325 int
326 default 2 if ARM64_16K_PAGES && ARM64_VA_BITS_36
327 default 2 if ARM64_64K_PAGES && ARM64_VA_BITS_42
328 default 3 if ARM64_64K_PAGES && (ARM64_VA_BITS_48 || ARM64_VA_BITS_52)
329 default 3 if ARM64_4K_PAGES && ARM64_VA_BITS_39
330 default 3 if ARM64_16K_PAGES && ARM64_VA_BITS_47
331 default 4 if !ARM64_64K_PAGES && ARM64_VA_BITS_48
332
333config ARCH_SUPPORTS_UPROBES
334 def_bool y
335
336config ARCH_PROC_KCORE_TEXT
337 def_bool y
338
339config BROKEN_GAS_INST
340 def_bool !$(as-instr,1:\n.inst 0\n.rept . - 1b\n\nnop\n.endr\n)
341
342config KASAN_SHADOW_OFFSET
343 hex
344 depends on KASAN_GENERIC || KASAN_SW_TAGS
345 default 0xdfff800000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && !KASAN_SW_TAGS
346 default 0xdfffc00000000000 if ARM64_VA_BITS_47 && !KASAN_SW_TAGS
347 default 0xdffffe0000000000 if ARM64_VA_BITS_42 && !KASAN_SW_TAGS
348 default 0xdfffffc000000000 if ARM64_VA_BITS_39 && !KASAN_SW_TAGS
349 default 0xdffffff800000000 if ARM64_VA_BITS_36 && !KASAN_SW_TAGS
350 default 0xefff800000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && KASAN_SW_TAGS
351 default 0xefffc00000000000 if ARM64_VA_BITS_47 && KASAN_SW_TAGS
352 default 0xeffffe0000000000 if ARM64_VA_BITS_42 && KASAN_SW_TAGS
353 default 0xefffffc000000000 if ARM64_VA_BITS_39 && KASAN_SW_TAGS
354 default 0xeffffff800000000 if ARM64_VA_BITS_36 && KASAN_SW_TAGS
355 default 0xffffffffffffffff
356
357source "arch/arm64/Kconfig.platforms"
358
359menu "Kernel Features"
360
361menu "ARM errata workarounds via the alternatives framework"
362
363config ARM64_WORKAROUND_CLEAN_CACHE
364 bool
365
366config ARM64_ERRATUM_826319
367 bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted"
368 default y
369 select ARM64_WORKAROUND_CLEAN_CACHE
370 help
371 This option adds an alternative code sequence to work around ARM
372 erratum 826319 on Cortex-A53 parts up to r0p2 with an AMBA 4 ACE or
373 AXI master interface and an L2 cache.
374
375 If a Cortex-A53 uses an AMBA AXI4 ACE interface to other processors
376 and is unable to accept a certain write via this interface, it will
377 not progress on read data presented on the read data channel and the
378 system can deadlock.
379
380 The workaround promotes data cache clean instructions to
381 data cache clean-and-invalidate.
382 Please note that this does not necessarily enable the workaround,
383 as it depends on the alternative framework, which will only patch
384 the kernel if an affected CPU is detected.
385
386 If unsure, say Y.
387
388config ARM64_ERRATUM_827319
389 bool "Cortex-A53: 827319: Data cache clean instructions might cause overlapping transactions to the interconnect"
390 default y
391 select ARM64_WORKAROUND_CLEAN_CACHE
392 help
393 This option adds an alternative code sequence to work around ARM
394 erratum 827319 on Cortex-A53 parts up to r0p2 with an AMBA 5 CHI
395 master interface and an L2 cache.
396
397 Under certain conditions this erratum can cause a clean line eviction
398 to occur at the same time as another transaction to the same address
399 on the AMBA 5 CHI interface, which can cause data corruption if the
400 interconnect reorders the two transactions.
401
402 The workaround promotes data cache clean instructions to
403 data cache clean-and-invalidate.
404 Please note that this does not necessarily enable the workaround,
405 as it depends on the alternative framework, which will only patch
406 the kernel if an affected CPU is detected.
407
408 If unsure, say Y.
409
410config ARM64_ERRATUM_824069
411 bool "Cortex-A53: 824069: Cache line might not be marked as clean after a CleanShared snoop"
412 default y
413 select ARM64_WORKAROUND_CLEAN_CACHE
414 help
415 This option adds an alternative code sequence to work around ARM
416 erratum 824069 on Cortex-A53 parts up to r0p2 when it is connected
417 to a coherent interconnect.
418
419 If a Cortex-A53 processor is executing a store or prefetch for
420 write instruction at the same time as a processor in another
421 cluster is executing a cache maintenance operation to the same
422 address, then this erratum might cause a clean cache line to be
423 incorrectly marked as dirty.
424
425 The workaround promotes data cache clean instructions to
426 data cache clean-and-invalidate.
427 Please note that this option does not necessarily enable the
428 workaround, as it depends on the alternative framework, which will
429 only patch the kernel if an affected CPU is detected.
430
431 If unsure, say Y.
432
433config ARM64_ERRATUM_819472
434 bool "Cortex-A53: 819472: Store exclusive instructions might cause data corruption"
435 default y
436 select ARM64_WORKAROUND_CLEAN_CACHE
437 help
438 This option adds an alternative code sequence to work around ARM
439 erratum 819472 on Cortex-A53 parts up to r0p1 with an L2 cache
440 present when it is connected to a coherent interconnect.
441
442 If the processor is executing a load and store exclusive sequence at
443 the same time as a processor in another cluster is executing a cache
444 maintenance operation to the same address, then this erratum might
445 cause data corruption.
446
447 The workaround promotes data cache clean instructions to
448 data cache clean-and-invalidate.
449 Please note that this does not necessarily enable the workaround,
450 as it depends on the alternative framework, which will only patch
451 the kernel if an affected CPU is detected.
452
453 If unsure, say Y.
454
455config ARM64_ERRATUM_832075
456 bool "Cortex-A57: 832075: possible deadlock on mixing exclusive memory accesses with device loads"
457 default y
458 help
459 This option adds an alternative code sequence to work around ARM
460 erratum 832075 on Cortex-A57 parts up to r1p2.
461
462 Affected Cortex-A57 parts might deadlock when exclusive load/store
463 instructions to Write-Back memory are mixed with Device loads.
464
465 The workaround is to promote device loads to use Load-Acquire
466 semantics.
467 Please note that this does not necessarily enable the workaround,
468 as it depends on the alternative framework, which will only patch
469 the kernel if an affected CPU is detected.
470
471 If unsure, say Y.
472
473config ARM64_ERRATUM_834220
474 bool "Cortex-A57: 834220: Stage 2 translation fault might be incorrectly reported in presence of a Stage 1 fault"
475 depends on KVM
476 default y
477 help
478 This option adds an alternative code sequence to work around ARM
479 erratum 834220 on Cortex-A57 parts up to r1p2.
480
481 Affected Cortex-A57 parts might report a Stage 2 translation
482 fault as the result of a Stage 1 fault for load crossing a
483 page boundary when there is a permission or device memory
484 alignment fault at Stage 1 and a translation fault at Stage 2.
485
486 The workaround is to verify that the Stage 1 translation
487 doesn't generate a fault before handling the Stage 2 fault.
488 Please note that this does not necessarily enable the workaround,
489 as it depends on the alternative framework, which will only patch
490 the kernel if an affected CPU is detected.
491
492 If unsure, say Y.
493
494config ARM64_ERRATUM_845719
495 bool "Cortex-A53: 845719: a load might read incorrect data"
496 depends on COMPAT
497 default y
498 help
499 This option adds an alternative code sequence to work around ARM
500 erratum 845719 on Cortex-A53 parts up to r0p4.
501
502 When running a compat (AArch32) userspace on an affected Cortex-A53
503 part, a load at EL0 from a virtual address that matches the bottom 32
504 bits of the virtual address used by a recent load at (AArch64) EL1
505 might return incorrect data.
506
507 The workaround is to write the contextidr_el1 register on exception
508 return to a 32-bit task.
509 Please note that this does not necessarily enable the workaround,
510 as it depends on the alternative framework, which will only patch
511 the kernel if an affected CPU is detected.
512
513 If unsure, say Y.
514
515config ARM64_ERRATUM_843419
516 bool "Cortex-A53: 843419: A load or store might access an incorrect address"
517 default y
518 select ARM64_MODULE_PLTS if MODULES
519 help
520 This option links the kernel with '--fix-cortex-a53-843419' and
521 enables PLT support to replace certain ADRP instructions, which can
522 cause subsequent memory accesses to use an incorrect address on
523 Cortex-A53 parts up to r0p4.
524
525 If unsure, say Y.
526
527config ARM64_LD_HAS_FIX_ERRATUM_843419
528 def_bool $(ld-option,--fix-cortex-a53-843419)
529
530config ARM64_ERRATUM_1024718
531 bool "Cortex-A55: 1024718: Update of DBM/AP bits without break before make might result in incorrect update"
532 default y
533 help
534 This option adds a workaround for ARM Cortex-A55 Erratum 1024718.
535
536 Affected Cortex-A55 cores (all revisions) could cause incorrect
537 update of the hardware dirty bit when the DBM/AP bits are updated
538 without a break-before-make. The workaround is to disable the usage
539 of hardware DBM locally on the affected cores. CPUs not affected by
540 this erratum will continue to use the feature.
541
542 If unsure, say Y.
543
544config ARM64_ERRATUM_1418040
545 bool "Cortex-A76/Neoverse-N1: MRC read following MRRC read of specific Generic Timer in AArch32 might give incorrect result"
546 default y
547 depends on COMPAT
548 help
549 This option adds a workaround for ARM Cortex-A76/Neoverse-N1
550 errata 1188873 and 1418040.
551
552 Affected Cortex-A76/Neoverse-N1 cores (r0p0 to r3p1) could
553 cause register corruption when accessing the timer registers
554 from AArch32 userspace.
555
556 If unsure, say Y.
557
558config ARM64_WORKAROUND_SPECULATIVE_AT
559 bool
560
561config ARM64_ERRATUM_1165522
562 bool "Cortex-A76: 1165522: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
563 default y
564 select ARM64_WORKAROUND_SPECULATIVE_AT
565 help
566 This option adds a workaround for ARM Cortex-A76 erratum 1165522.
567
568 Affected Cortex-A76 cores (r0p0, r1p0, r2p0) could end-up with
569 corrupted TLBs by speculating an AT instruction during a guest
570 context switch.
571
572 If unsure, say Y.
573
574config ARM64_ERRATUM_1319367
575 bool "Cortex-A57/A72: 1319537: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
576 default y
577 select ARM64_WORKAROUND_SPECULATIVE_AT
578 help
579 This option adds work arounds for ARM Cortex-A57 erratum 1319537
580 and A72 erratum 1319367
581
582 Cortex-A57 and A72 cores could end-up with corrupted TLBs by
583 speculating an AT instruction during a guest context switch.
584
585 If unsure, say Y.
586
587config ARM64_ERRATUM_1530923
588 bool "Cortex-A55: 1530923: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
589 default y
590 select ARM64_WORKAROUND_SPECULATIVE_AT
591 help
592 This option adds a workaround for ARM Cortex-A55 erratum 1530923.
593
594 Affected Cortex-A55 cores (r0p0, r0p1, r1p0, r2p0) could end-up with
595 corrupted TLBs by speculating an AT instruction during a guest
596 context switch.
597
598 If unsure, say Y.
599
600config ARM64_WORKAROUND_REPEAT_TLBI
601 bool
602
603config ARM64_ERRATUM_1286807
604 bool "Cortex-A76: Modification of the translation table for a virtual address might lead to read-after-read ordering violation"
605 default y
606 select ARM64_WORKAROUND_REPEAT_TLBI
607 help
608 This option adds a workaround for ARM Cortex-A76 erratum 1286807.
609
610 On the affected Cortex-A76 cores (r0p0 to r3p0), if a virtual
611 address for a cacheable mapping of a location is being
612 accessed by a core while another core is remapping the virtual
613 address to a new physical page using the recommended
614 break-before-make sequence, then under very rare circumstances
615 TLBI+DSB completes before a read using the translation being
616 invalidated has been observed by other observers. The
617 workaround repeats the TLBI+DSB operation.
618
619config ARM64_ERRATUM_1463225
620 bool "Cortex-A76: Software Step might prevent interrupt recognition"
621 default y
622 help
623 This option adds a workaround for Arm Cortex-A76 erratum 1463225.
624
625 On the affected Cortex-A76 cores (r0p0 to r3p1), software stepping
626 of a system call instruction (SVC) can prevent recognition of
627 subsequent interrupts when software stepping is disabled in the
628 exception handler of the system call and either kernel debugging
629 is enabled or VHE is in use.
630
631 Work around the erratum by triggering a dummy step exception
632 when handling a system call from a task that is being stepped
633 in a VHE configuration of the kernel.
634
635 If unsure, say Y.
636
637config ARM64_ERRATUM_1542419
638 bool "Neoverse-N1: workaround mis-ordering of instruction fetches"
639 default y
640 help
641 This option adds a workaround for ARM Neoverse-N1 erratum
642 1542419.
643
644 Affected Neoverse-N1 cores could execute a stale instruction when
645 modified by another CPU. The workaround depends on a firmware
646 counterpart.
647
648 Workaround the issue by hiding the DIC feature from EL0. This
649 forces user-space to perform cache maintenance.
650
651 If unsure, say Y.
652
653config ARM64_ERRATUM_1508412
654 bool "Cortex-A77: 1508412: workaround deadlock on sequence of NC/Device load and store exclusive or PAR read"
655 default y
656 help
657 This option adds a workaround for Arm Cortex-A77 erratum 1508412.
658
659 Affected Cortex-A77 cores (r0p0, r1p0) could deadlock on a sequence
660 of a store-exclusive or read of PAR_EL1 and a load with device or
661 non-cacheable memory attributes. The workaround depends on a firmware
662 counterpart.
663
664 KVM guests must also have the workaround implemented or they can
665 deadlock the system.
666
667 Work around the issue by inserting DMB SY barriers around PAR_EL1
668 register reads and warning KVM users. The DMB barrier is sufficient
669 to prevent a speculative PAR_EL1 read.
670
671 If unsure, say Y.
672
673config CAVIUM_ERRATUM_22375
674 bool "Cavium erratum 22375, 24313"
675 default y
676 help
677 Enable workaround for errata 22375 and 24313.
678
679 This implements two gicv3-its errata workarounds for ThunderX. Both
680 with a small impact affecting only ITS table allocation.
681
682 erratum 22375: only alloc 8MB table size
683 erratum 24313: ignore memory access type
684
685 The fixes are in ITS initialization and basically ignore memory access
686 type and table size provided by the TYPER and BASER registers.
687
688 If unsure, say Y.
689
690config CAVIUM_ERRATUM_23144
691 bool "Cavium erratum 23144: ITS SYNC hang on dual socket system"
692 depends on NUMA
693 default y
694 help
695 ITS SYNC command hang for cross node io and collections/cpu mapping.
696
697 If unsure, say Y.
698
699config CAVIUM_ERRATUM_23154
700 bool "Cavium erratum 23154: Access to ICC_IAR1_EL1 is not sync'ed"
701 default y
702 help
703 The gicv3 of ThunderX requires a modified version for
704 reading the IAR status to ensure data synchronization
705 (access to icc_iar1_el1 is not sync'ed before and after).
706
707 If unsure, say Y.
708
709config CAVIUM_ERRATUM_27456
710 bool "Cavium erratum 27456: Broadcast TLBI instructions may cause icache corruption"
711 default y
712 help
713 On ThunderX T88 pass 1.x through 2.1 parts, broadcast TLBI
714 instructions may cause the icache to become corrupted if it
715 contains data for a non-current ASID. The fix is to
716 invalidate the icache when changing the mm context.
717
718 If unsure, say Y.
719
720config CAVIUM_ERRATUM_30115
721 bool "Cavium erratum 30115: Guest may disable interrupts in host"
722 default y
723 help
724 On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through
725 1.2, and T83 Pass 1.0, KVM guest execution may disable
726 interrupts in host. Trapping both GICv3 group-0 and group-1
727 accesses sidesteps the issue.
728
729 If unsure, say Y.
730
731config CAVIUM_TX2_ERRATUM_219
732 bool "Cavium ThunderX2 erratum 219: PRFM between TTBR change and ISB fails"
733 default y
734 help
735 On Cavium ThunderX2, a load, store or prefetch instruction between a
736 TTBR update and the corresponding context synchronizing operation can
737 cause a spurious Data Abort to be delivered to any hardware thread in
738 the CPU core.
739
740 Work around the issue by avoiding the problematic code sequence and
741 trapping KVM guest TTBRx_EL1 writes to EL2 when SMT is enabled. The
742 trap handler performs the corresponding register access, skips the
743 instruction and ensures context synchronization by virtue of the
744 exception return.
745
746 If unsure, say Y.
747
748config FUJITSU_ERRATUM_010001
749 bool "Fujitsu-A64FX erratum E#010001: Undefined fault may occur wrongly"
750 default y
751 help
752 This option adds a workaround for Fujitsu-A64FX erratum E#010001.
753 On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1), memory
754 accesses may cause undefined fault (Data abort, DFSC=0b111111).
755 This fault occurs under a specific hardware condition when a
756 load/store instruction performs an address translation using:
757 case-1 TTBR0_EL1 with TCR_EL1.NFD0 == 1.
758 case-2 TTBR0_EL2 with TCR_EL2.NFD0 == 1.
759 case-3 TTBR1_EL1 with TCR_EL1.NFD1 == 1.
760 case-4 TTBR1_EL2 with TCR_EL2.NFD1 == 1.
761
762 The workaround is to ensure these bits are clear in TCR_ELx.
763 The workaround only affects the Fujitsu-A64FX.
764
765 If unsure, say Y.
766
767config HISILICON_ERRATUM_161600802
768 bool "Hip07 161600802: Erroneous redistributor VLPI base"
769 default y
770 help
771 The HiSilicon Hip07 SoC uses the wrong redistributor base
772 when issued ITS commands such as VMOVP and VMAPP, and requires
773 a 128kB offset to be applied to the target address in this commands.
774
775 If unsure, say Y.
776
777config QCOM_FALKOR_ERRATUM_1003
778 bool "Falkor E1003: Incorrect translation due to ASID change"
779 default y
780 help
781 On Falkor v1, an incorrect ASID may be cached in the TLB when ASID
782 and BADDR are changed together in TTBRx_EL1. Since we keep the ASID
783 in TTBR1_EL1, this situation only occurs in the entry trampoline and
784 then only for entries in the walk cache, since the leaf translation
785 is unchanged. Work around the erratum by invalidating the walk cache
786 entries for the trampoline before entering the kernel proper.
787
788config QCOM_FALKOR_ERRATUM_1009
789 bool "Falkor E1009: Prematurely complete a DSB after a TLBI"
790 default y
791 select ARM64_WORKAROUND_REPEAT_TLBI
792 help
793 On Falkor v1, the CPU may prematurely complete a DSB following a
794 TLBI xxIS invalidate maintenance operation. Repeat the TLBI operation
795 one more time to fix the issue.
796
797 If unsure, say Y.
798
799config QCOM_QDF2400_ERRATUM_0065
800 bool "QDF2400 E0065: Incorrect GITS_TYPER.ITT_Entry_size"
801 default y
802 help
803 On Qualcomm Datacenter Technologies QDF2400 SoC, ITS hardware reports
804 ITE size incorrectly. The GITS_TYPER.ITT_Entry_size field should have
805 been indicated as 16Bytes (0xf), not 8Bytes (0x7).
806
807 If unsure, say Y.
808
809config QCOM_FALKOR_ERRATUM_E1041
810 bool "Falkor E1041: Speculative instruction fetches might cause errant memory access"
811 default y
812 help
813 Falkor CPU may speculatively fetch instructions from an improper
814 memory location when MMU translation is changed from SCTLR_ELn[M]=1
815 to SCTLR_ELn[M]=0. Prefix an ISB instruction to fix the problem.
816
817 If unsure, say Y.
818
819config NVIDIA_CARMEL_CNP_ERRATUM
820 bool "NVIDIA Carmel CNP: CNP on Carmel semantically different than ARM cores"
821 default y
822 help
823 If CNP is enabled on Carmel cores, non-sharable TLBIs on a core will not
824 invalidate shared TLB entries installed by a different core, as it would
825 on standard ARM cores.
826
827 If unsure, say Y.
828
829config SOCIONEXT_SYNQUACER_PREITS
830 bool "Socionext Synquacer: Workaround for GICv3 pre-ITS"
831 default y
832 help
833 Socionext Synquacer SoCs implement a separate h/w block to generate
834 MSI doorbell writes with non-zero values for the device ID.
835
836 If unsure, say Y.
837
838endmenu
839
840
841choice
842 prompt "Page size"
843 default ARM64_4K_PAGES
844 help
845 Page size (translation granule) configuration.
846
847config ARM64_4K_PAGES
848 bool "4KB"
849 help
850 This feature enables 4KB pages support.
851
852config ARM64_16K_PAGES
853 bool "16KB"
854 help
855 The system will use 16KB pages support. AArch32 emulation
856 requires applications compiled with 16K (or a multiple of 16K)
857 aligned segments.
858
859config ARM64_64K_PAGES
860 bool "64KB"
861 help
862 This feature enables 64KB pages support (4KB by default)
863 allowing only two levels of page tables and faster TLB
864 look-up. AArch32 emulation requires applications compiled
865 with 64K aligned segments.
866
867endchoice
868
869choice
870 prompt "Virtual address space size"
871 default ARM64_VA_BITS_39 if ARM64_4K_PAGES
872 default ARM64_VA_BITS_47 if ARM64_16K_PAGES
873 default ARM64_VA_BITS_42 if ARM64_64K_PAGES
874 help
875 Allows choosing one of multiple possible virtual address
876 space sizes. The level of translation table is determined by
877 a combination of page size and virtual address space size.
878
879config ARM64_VA_BITS_36
880 bool "36-bit" if EXPERT
881 depends on ARM64_16K_PAGES
882
883config ARM64_VA_BITS_39
884 bool "39-bit"
885 depends on ARM64_4K_PAGES
886
887config ARM64_VA_BITS_42
888 bool "42-bit"
889 depends on ARM64_64K_PAGES
890
891config ARM64_VA_BITS_47
892 bool "47-bit"
893 depends on ARM64_16K_PAGES
894
895config ARM64_VA_BITS_48
896 bool "48-bit"
897
898config ARM64_VA_BITS_52
899 bool "52-bit"
900 depends on ARM64_64K_PAGES && (ARM64_PAN || !ARM64_SW_TTBR0_PAN)
901 help
902 Enable 52-bit virtual addressing for userspace when explicitly
903 requested via a hint to mmap(). The kernel will also use 52-bit
904 virtual addresses for its own mappings (provided HW support for
905 this feature is available, otherwise it reverts to 48-bit).
906
907 NOTE: Enabling 52-bit virtual addressing in conjunction with
908 ARMv8.3 Pointer Authentication will result in the PAC being
909 reduced from 7 bits to 3 bits, which may have a significant
910 impact on its susceptibility to brute-force attacks.
911
912 If unsure, select 48-bit virtual addressing instead.
913
914endchoice
915
916config ARM64_FORCE_52BIT
917 bool "Force 52-bit virtual addresses for userspace"
918 depends on ARM64_VA_BITS_52 && EXPERT
919 help
920 For systems with 52-bit userspace VAs enabled, the kernel will attempt
921 to maintain compatibility with older software by providing 48-bit VAs
922 unless a hint is supplied to mmap.
923
924 This configuration option disables the 48-bit compatibility logic, and
925 forces all userspace addresses to be 52-bit on HW that supports it. One
926 should only enable this configuration option for stress testing userspace
927 memory management code. If unsure say N here.
928
929config ARM64_VA_BITS
930 int
931 default 36 if ARM64_VA_BITS_36
932 default 39 if ARM64_VA_BITS_39
933 default 42 if ARM64_VA_BITS_42
934 default 47 if ARM64_VA_BITS_47
935 default 48 if ARM64_VA_BITS_48
936 default 52 if ARM64_VA_BITS_52
937
938choice
939 prompt "Physical address space size"
940 default ARM64_PA_BITS_48
941 help
942 Choose the maximum physical address range that the kernel will
943 support.
944
945config ARM64_PA_BITS_48
946 bool "48-bit"
947
948config ARM64_PA_BITS_52
949 bool "52-bit (ARMv8.2)"
950 depends on ARM64_64K_PAGES
951 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
952 help
953 Enable support for a 52-bit physical address space, introduced as
954 part of the ARMv8.2-LPA extension.
955
956 With this enabled, the kernel will also continue to work on CPUs that
957 do not support ARMv8.2-LPA, but with some added memory overhead (and
958 minor performance overhead).
959
960endchoice
961
962config ARM64_PA_BITS
963 int
964 default 48 if ARM64_PA_BITS_48
965 default 52 if ARM64_PA_BITS_52
966
967choice
968 prompt "Endianness"
969 default CPU_LITTLE_ENDIAN
970 help
971 Select the endianness of data accesses performed by the CPU. Userspace
972 applications will need to be compiled and linked for the endianness
973 that is selected here.
974
975config CPU_BIG_ENDIAN
976 bool "Build big-endian kernel"
977 depends on !LD_IS_LLD || LLD_VERSION >= 130000
978 help
979 Say Y if you plan on running a kernel with a big-endian userspace.
980
981config CPU_LITTLE_ENDIAN
982 bool "Build little-endian kernel"
983 help
984 Say Y if you plan on running a kernel with a little-endian userspace.
985 This is usually the case for distributions targeting arm64.
986
987endchoice
988
989config SCHED_MC
990 bool "Multi-core scheduler support"
991 help
992 Multi-core scheduler support improves the CPU scheduler's decision
993 making when dealing with multi-core CPU chips at a cost of slightly
994 increased overhead in some places. If unsure say N here.
995
996config SCHED_SMT
997 bool "SMT scheduler support"
998 help
999 Improves the CPU scheduler's decision making when dealing with
1000 MultiThreading at a cost of slightly increased overhead in some
1001 places. If unsure say N here.
1002
1003config NR_CPUS
1004 int "Maximum number of CPUs (2-4096)"
1005 range 2 4096
1006 default "256"
1007
1008config HOTPLUG_CPU
1009 bool "Support for hot-pluggable CPUs"
1010 select GENERIC_IRQ_MIGRATION
1011 help
1012 Say Y here to experiment with turning CPUs off and on. CPUs
1013 can be controlled through /sys/devices/system/cpu.
1014
1015# Common NUMA Features
1016config NUMA
1017 bool "NUMA Memory Allocation and Scheduler Support"
1018 select GENERIC_ARCH_NUMA
1019 select ACPI_NUMA if ACPI
1020 select OF_NUMA
1021 help
1022 Enable NUMA (Non-Uniform Memory Access) support.
1023
1024 The kernel will try to allocate memory used by a CPU on the
1025 local memory of the CPU and add some more
1026 NUMA awareness to the kernel.
1027
1028config NODES_SHIFT
1029 int "Maximum NUMA Nodes (as a power of 2)"
1030 range 1 10
1031 default "4"
1032 depends on NUMA
1033 help
1034 Specify the maximum number of NUMA Nodes available on the target
1035 system. Increases memory reserved to accommodate various tables.
1036
1037config USE_PERCPU_NUMA_NODE_ID
1038 def_bool y
1039 depends on NUMA
1040
1041config HAVE_SETUP_PER_CPU_AREA
1042 def_bool y
1043 depends on NUMA
1044
1045config NEED_PER_CPU_EMBED_FIRST_CHUNK
1046 def_bool y
1047 depends on NUMA
1048
1049source "kernel/Kconfig.hz"
1050
1051config ARCH_SPARSEMEM_ENABLE
1052 def_bool y
1053 select SPARSEMEM_VMEMMAP_ENABLE
1054 select SPARSEMEM_VMEMMAP
1055
1056config HW_PERF_EVENTS
1057 def_bool y
1058 depends on ARM_PMU
1059
1060config ARCH_HAS_FILTER_PGPROT
1061 def_bool y
1062
1063# Supported by clang >= 7.0
1064config CC_HAVE_SHADOW_CALL_STACK
1065 def_bool $(cc-option, -fsanitize=shadow-call-stack -ffixed-x18)
1066
1067config PARAVIRT
1068 bool "Enable paravirtualization code"
1069 help
1070 This changes the kernel so it can modify itself when it is run
1071 under a hypervisor, potentially improving performance significantly
1072 over full virtualization.
1073
1074config PARAVIRT_TIME_ACCOUNTING
1075 bool "Paravirtual steal time accounting"
1076 select PARAVIRT
1077 help
1078 Select this option to enable fine granularity task steal time
1079 accounting. Time spent executing other tasks in parallel with
1080 the current vCPU is discounted from the vCPU power. To account for
1081 that, there can be a small performance impact.
1082
1083 If in doubt, say N here.
1084
1085config KEXEC
1086 depends on PM_SLEEP_SMP
1087 select KEXEC_CORE
1088 bool "kexec system call"
1089 help
1090 kexec is a system call that implements the ability to shutdown your
1091 current kernel, and to start another kernel. It is like a reboot
1092 but it is independent of the system firmware. And like a reboot
1093 you can start any kernel with it, not just Linux.
1094
1095config KEXEC_FILE
1096 bool "kexec file based system call"
1097 select KEXEC_CORE
1098 select HAVE_IMA_KEXEC if IMA
1099 help
1100 This is new version of kexec system call. This system call is
1101 file based and takes file descriptors as system call argument
1102 for kernel and initramfs as opposed to list of segments as
1103 accepted by previous system call.
1104
1105config KEXEC_SIG
1106 bool "Verify kernel signature during kexec_file_load() syscall"
1107 depends on KEXEC_FILE
1108 help
1109 Select this option to verify a signature with loaded kernel
1110 image. If configured, any attempt of loading a image without
1111 valid signature will fail.
1112
1113 In addition to that option, you need to enable signature
1114 verification for the corresponding kernel image type being
1115 loaded in order for this to work.
1116
1117config KEXEC_IMAGE_VERIFY_SIG
1118 bool "Enable Image signature verification support"
1119 default y
1120 depends on KEXEC_SIG
1121 depends on EFI && SIGNED_PE_FILE_VERIFICATION
1122 help
1123 Enable Image signature verification support.
1124
1125comment "Support for PE file signature verification disabled"
1126 depends on KEXEC_SIG
1127 depends on !EFI || !SIGNED_PE_FILE_VERIFICATION
1128
1129config CRASH_DUMP
1130 bool "Build kdump crash kernel"
1131 help
1132 Generate crash dump after being started by kexec. This should
1133 be normally only set in special crash dump kernels which are
1134 loaded in the main kernel with kexec-tools into a specially
1135 reserved region and then later executed after a crash by
1136 kdump/kexec.
1137
1138 For more details see Documentation/admin-guide/kdump/kdump.rst
1139
1140config TRANS_TABLE
1141 def_bool y
1142 depends on HIBERNATION
1143
1144config XEN_DOM0
1145 def_bool y
1146 depends on XEN
1147
1148config XEN
1149 bool "Xen guest support on ARM64"
1150 depends on ARM64 && OF
1151 select SWIOTLB_XEN
1152 select PARAVIRT
1153 help
1154 Say Y if you want to run Linux in a Virtual Machine on Xen on ARM64.
1155
1156config FORCE_MAX_ZONEORDER
1157 int
1158 default "14" if ARM64_64K_PAGES
1159 default "12" if ARM64_16K_PAGES
1160 default "11"
1161 help
1162 The kernel memory allocator divides physically contiguous memory
1163 blocks into "zones", where each zone is a power of two number of
1164 pages. This option selects the largest power of two that the kernel
1165 keeps in the memory allocator. If you need to allocate very large
1166 blocks of physically contiguous memory, then you may need to
1167 increase this value.
1168
1169 This config option is actually maximum order plus one. For example,
1170 a value of 11 means that the largest free memory block is 2^10 pages.
1171
1172 We make sure that we can allocate upto a HugePage size for each configuration.
1173 Hence we have :
1174 MAX_ORDER = (PMD_SHIFT - PAGE_SHIFT) + 1 => PAGE_SHIFT - 2
1175
1176 However for 4K, we choose a higher default value, 11 as opposed to 10, giving us
1177 4M allocations matching the default size used by generic code.
1178
1179config UNMAP_KERNEL_AT_EL0
1180 bool "Unmap kernel when running in userspace (aka \"KAISER\")" if EXPERT
1181 default y
1182 help
1183 Speculation attacks against some high-performance processors can
1184 be used to bypass MMU permission checks and leak kernel data to
1185 userspace. This can be defended against by unmapping the kernel
1186 when running in userspace, mapping it back in on exception entry
1187 via a trampoline page in the vector table.
1188
1189 If unsure, say Y.
1190
1191config RODATA_FULL_DEFAULT_ENABLED
1192 bool "Apply r/o permissions of VM areas also to their linear aliases"
1193 default y
1194 help
1195 Apply read-only attributes of VM areas to the linear alias of
1196 the backing pages as well. This prevents code or read-only data
1197 from being modified (inadvertently or intentionally) via another
1198 mapping of the same memory page. This additional enhancement can
1199 be turned off at runtime by passing rodata=[off|on] (and turned on
1200 with rodata=full if this option is set to 'n')
1201
1202 This requires the linear region to be mapped down to pages,
1203 which may adversely affect performance in some cases.
1204
1205config ARM64_SW_TTBR0_PAN
1206 bool "Emulate Privileged Access Never using TTBR0_EL1 switching"
1207 help
1208 Enabling this option prevents the kernel from accessing
1209 user-space memory directly by pointing TTBR0_EL1 to a reserved
1210 zeroed area and reserved ASID. The user access routines
1211 restore the valid TTBR0_EL1 temporarily.
1212
1213config ARM64_TAGGED_ADDR_ABI
1214 bool "Enable the tagged user addresses syscall ABI"
1215 default y
1216 help
1217 When this option is enabled, user applications can opt in to a
1218 relaxed ABI via prctl() allowing tagged addresses to be passed
1219 to system calls as pointer arguments. For details, see
1220 Documentation/arm64/tagged-address-abi.rst.
1221
1222menuconfig COMPAT
1223 bool "Kernel support for 32-bit EL0"
1224 depends on ARM64_4K_PAGES || EXPERT
1225 select HAVE_UID16
1226 select OLD_SIGSUSPEND3
1227 select COMPAT_OLD_SIGACTION
1228 help
1229 This option enables support for a 32-bit EL0 running under a 64-bit
1230 kernel at EL1. AArch32-specific components such as system calls,
1231 the user helper functions, VFP support and the ptrace interface are
1232 handled appropriately by the kernel.
1233
1234 If you use a page size other than 4KB (i.e, 16KB or 64KB), please be aware
1235 that you will only be able to execute AArch32 binaries that were compiled
1236 with page size aligned segments.
1237
1238 If you want to execute 32-bit userspace applications, say Y.
1239
1240if COMPAT
1241
1242config KUSER_HELPERS
1243 bool "Enable kuser helpers page for 32-bit applications"
1244 default y
1245 help
1246 Warning: disabling this option may break 32-bit user programs.
1247
1248 Provide kuser helpers to compat tasks. The kernel provides
1249 helper code to userspace in read only form at a fixed location
1250 to allow userspace to be independent of the CPU type fitted to
1251 the system. This permits binaries to be run on ARMv4 through
1252 to ARMv8 without modification.
1253
1254 See Documentation/arm/kernel_user_helpers.rst for details.
1255
1256 However, the fixed address nature of these helpers can be used
1257 by ROP (return orientated programming) authors when creating
1258 exploits.
1259
1260 If all of the binaries and libraries which run on your platform
1261 are built specifically for your platform, and make no use of
1262 these helpers, then you can turn this option off to hinder
1263 such exploits. However, in that case, if a binary or library
1264 relying on those helpers is run, it will not function correctly.
1265
1266 Say N here only if you are absolutely certain that you do not
1267 need these helpers; otherwise, the safe option is to say Y.
1268
1269config COMPAT_VDSO
1270 bool "Enable vDSO for 32-bit applications"
1271 depends on !CPU_BIG_ENDIAN && "$(CROSS_COMPILE_COMPAT)" != ""
1272 select GENERIC_COMPAT_VDSO
1273 default y
1274 help
1275 Place in the process address space of 32-bit applications an
1276 ELF shared object providing fast implementations of gettimeofday
1277 and clock_gettime.
1278
1279 You must have a 32-bit build of glibc 2.22 or later for programs
1280 to seamlessly take advantage of this.
1281
1282config THUMB2_COMPAT_VDSO
1283 bool "Compile the 32-bit vDSO for Thumb-2 mode" if EXPERT
1284 depends on COMPAT_VDSO
1285 default y
1286 help
1287 Compile the compat vDSO with '-mthumb -fomit-frame-pointer' if y,
1288 otherwise with '-marm'.
1289
1290menuconfig ARMV8_DEPRECATED
1291 bool "Emulate deprecated/obsolete ARMv8 instructions"
1292 depends on SYSCTL
1293 help
1294 Legacy software support may require certain instructions
1295 that have been deprecated or obsoleted in the architecture.
1296
1297 Enable this config to enable selective emulation of these
1298 features.
1299
1300 If unsure, say Y
1301
1302if ARMV8_DEPRECATED
1303
1304config SWP_EMULATION
1305 bool "Emulate SWP/SWPB instructions"
1306 help
1307 ARMv8 obsoletes the use of A32 SWP/SWPB instructions such that
1308 they are always undefined. Say Y here to enable software
1309 emulation of these instructions for userspace using LDXR/STXR.
1310 This feature can be controlled at runtime with the abi.swp
1311 sysctl which is disabled by default.
1312
1313 In some older versions of glibc [<=2.8] SWP is used during futex
1314 trylock() operations with the assumption that the code will not
1315 be preempted. This invalid assumption may be more likely to fail
1316 with SWP emulation enabled, leading to deadlock of the user
1317 application.
1318
1319 NOTE: when accessing uncached shared regions, LDXR/STXR rely
1320 on an external transaction monitoring block called a global
1321 monitor to maintain update atomicity. If your system does not
1322 implement a global monitor, this option can cause programs that
1323 perform SWP operations to uncached memory to deadlock.
1324
1325 If unsure, say Y
1326
1327config CP15_BARRIER_EMULATION
1328 bool "Emulate CP15 Barrier instructions"
1329 help
1330 The CP15 barrier instructions - CP15ISB, CP15DSB, and
1331 CP15DMB - are deprecated in ARMv8 (and ARMv7). It is
1332 strongly recommended to use the ISB, DSB, and DMB
1333 instructions instead.
1334
1335 Say Y here to enable software emulation of these
1336 instructions for AArch32 userspace code. When this option is
1337 enabled, CP15 barrier usage is traced which can help
1338 identify software that needs updating. This feature can be
1339 controlled at runtime with the abi.cp15_barrier sysctl.
1340
1341 If unsure, say Y
1342
1343config SETEND_EMULATION
1344 bool "Emulate SETEND instruction"
1345 help
1346 The SETEND instruction alters the data-endianness of the
1347 AArch32 EL0, and is deprecated in ARMv8.
1348
1349 Say Y here to enable software emulation of the instruction
1350 for AArch32 userspace code. This feature can be controlled
1351 at runtime with the abi.setend sysctl.
1352
1353 Note: All the cpus on the system must have mixed endian support at EL0
1354 for this feature to be enabled. If a new CPU - which doesn't support mixed
1355 endian - is hotplugged in after this feature has been enabled, there could
1356 be unexpected results in the applications.
1357
1358 If unsure, say Y
1359endif
1360
1361endif
1362
1363menu "ARMv8.1 architectural features"
1364
1365config ARM64_HW_AFDBM
1366 bool "Support for hardware updates of the Access and Dirty page flags"
1367 default y
1368 help
1369 The ARMv8.1 architecture extensions introduce support for
1370 hardware updates of the access and dirty information in page
1371 table entries. When enabled in TCR_EL1 (HA and HD bits) on
1372 capable processors, accesses to pages with PTE_AF cleared will
1373 set this bit instead of raising an access flag fault.
1374 Similarly, writes to read-only pages with the DBM bit set will
1375 clear the read-only bit (AP[2]) instead of raising a
1376 permission fault.
1377
1378 Kernels built with this configuration option enabled continue
1379 to work on pre-ARMv8.1 hardware and the performance impact is
1380 minimal. If unsure, say Y.
1381
1382config ARM64_PAN
1383 bool "Enable support for Privileged Access Never (PAN)"
1384 default y
1385 help
1386 Privileged Access Never (PAN; part of the ARMv8.1 Extensions)
1387 prevents the kernel or hypervisor from accessing user-space (EL0)
1388 memory directly.
1389
1390 Choosing this option will cause any unprotected (not using
1391 copy_to_user et al) memory access to fail with a permission fault.
1392
1393 The feature is detected at runtime, and will remain as a 'nop'
1394 instruction if the cpu does not implement the feature.
1395
1396config AS_HAS_LDAPR
1397 def_bool $(as-instr,.arch_extension rcpc)
1398
1399config AS_HAS_LSE_ATOMICS
1400 def_bool $(as-instr,.arch_extension lse)
1401
1402config ARM64_LSE_ATOMICS
1403 bool
1404 default ARM64_USE_LSE_ATOMICS
1405 depends on AS_HAS_LSE_ATOMICS
1406
1407config ARM64_USE_LSE_ATOMICS
1408 bool "Atomic instructions"
1409 depends on JUMP_LABEL
1410 default y
1411 help
1412 As part of the Large System Extensions, ARMv8.1 introduces new
1413 atomic instructions that are designed specifically to scale in
1414 very large systems.
1415
1416 Say Y here to make use of these instructions for the in-kernel
1417 atomic routines. This incurs a small overhead on CPUs that do
1418 not support these instructions and requires the kernel to be
1419 built with binutils >= 2.25 in order for the new instructions
1420 to be used.
1421
1422endmenu
1423
1424menu "ARMv8.2 architectural features"
1425
1426config ARM64_PMEM
1427 bool "Enable support for persistent memory"
1428 select ARCH_HAS_PMEM_API
1429 select ARCH_HAS_UACCESS_FLUSHCACHE
1430 help
1431 Say Y to enable support for the persistent memory API based on the
1432 ARMv8.2 DCPoP feature.
1433
1434 The feature is detected at runtime, and the kernel will use DC CVAC
1435 operations if DC CVAP is not supported (following the behaviour of
1436 DC CVAP itself if the system does not define a point of persistence).
1437
1438config ARM64_RAS_EXTN
1439 bool "Enable support for RAS CPU Extensions"
1440 default y
1441 help
1442 CPUs that support the Reliability, Availability and Serviceability
1443 (RAS) Extensions, part of ARMv8.2 are able to track faults and
1444 errors, classify them and report them to software.
1445
1446 On CPUs with these extensions system software can use additional
1447 barriers to determine if faults are pending and read the
1448 classification from a new set of registers.
1449
1450 Selecting this feature will allow the kernel to use these barriers
1451 and access the new registers if the system supports the extension.
1452 Platform RAS features may additionally depend on firmware support.
1453
1454config ARM64_CNP
1455 bool "Enable support for Common Not Private (CNP) translations"
1456 default y
1457 depends on ARM64_PAN || !ARM64_SW_TTBR0_PAN
1458 help
1459 Common Not Private (CNP) allows translation table entries to
1460 be shared between different PEs in the same inner shareable
1461 domain, so the hardware can use this fact to optimise the
1462 caching of such entries in the TLB.
1463
1464 Selecting this option allows the CNP feature to be detected
1465 at runtime, and does not affect PEs that do not implement
1466 this feature.
1467
1468endmenu
1469
1470menu "ARMv8.3 architectural features"
1471
1472config ARM64_PTR_AUTH
1473 bool "Enable support for pointer authentication"
1474 default y
1475 help
1476 Pointer authentication (part of the ARMv8.3 Extensions) provides
1477 instructions for signing and authenticating pointers against secret
1478 keys, which can be used to mitigate Return Oriented Programming (ROP)
1479 and other attacks.
1480
1481 This option enables these instructions at EL0 (i.e. for userspace).
1482 Choosing this option will cause the kernel to initialise secret keys
1483 for each process at exec() time, with these keys being
1484 context-switched along with the process.
1485
1486 The feature is detected at runtime. If the feature is not present in
1487 hardware it will not be advertised to userspace/KVM guest nor will it
1488 be enabled.
1489
1490 If the feature is present on the boot CPU but not on a late CPU, then
1491 the late CPU will be parked. Also, if the boot CPU does not have
1492 address auth and the late CPU has then the late CPU will still boot
1493 but with the feature disabled. On such a system, this option should
1494 not be selected.
1495
1496config ARM64_PTR_AUTH_KERNEL
1497 bool "Use pointer authentication for kernel"
1498 default y
1499 depends on ARM64_PTR_AUTH
1500 depends on (CC_HAS_SIGN_RETURN_ADDRESS || CC_HAS_BRANCH_PROT_PAC_RET) && AS_HAS_PAC
1501 # Modern compilers insert a .note.gnu.property section note for PAC
1502 # which is only understood by binutils starting with version 2.33.1.
1503 depends on LD_IS_LLD || LD_VERSION >= 23301 || (CC_IS_GCC && GCC_VERSION < 90100)
1504 depends on !CC_IS_CLANG || AS_HAS_CFI_NEGATE_RA_STATE
1505 depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS)
1506 help
1507 If the compiler supports the -mbranch-protection or
1508 -msign-return-address flag (e.g. GCC 7 or later), then this option
1509 will cause the kernel itself to be compiled with return address
1510 protection. In this case, and if the target hardware is known to
1511 support pointer authentication, then CONFIG_STACKPROTECTOR can be
1512 disabled with minimal loss of protection.
1513
1514 This feature works with FUNCTION_GRAPH_TRACER option only if
1515 DYNAMIC_FTRACE_WITH_REGS is enabled.
1516
1517config CC_HAS_BRANCH_PROT_PAC_RET
1518 # GCC 9 or later, clang 8 or later
1519 def_bool $(cc-option,-mbranch-protection=pac-ret+leaf)
1520
1521config CC_HAS_SIGN_RETURN_ADDRESS
1522 # GCC 7, 8
1523 def_bool $(cc-option,-msign-return-address=all)
1524
1525config AS_HAS_PAC
1526 def_bool $(cc-option,-Wa$(comma)-march=armv8.3-a)
1527
1528config AS_HAS_CFI_NEGATE_RA_STATE
1529 def_bool $(as-instr,.cfi_startproc\n.cfi_negate_ra_state\n.cfi_endproc\n)
1530
1531endmenu
1532
1533menu "ARMv8.4 architectural features"
1534
1535config ARM64_AMU_EXTN
1536 bool "Enable support for the Activity Monitors Unit CPU extension"
1537 default y
1538 help
1539 The activity monitors extension is an optional extension introduced
1540 by the ARMv8.4 CPU architecture. This enables support for version 1
1541 of the activity monitors architecture, AMUv1.
1542
1543 To enable the use of this extension on CPUs that implement it, say Y.
1544
1545 Note that for architectural reasons, firmware _must_ implement AMU
1546 support when running on CPUs that present the activity monitors
1547 extension. The required support is present in:
1548 * Version 1.5 and later of the ARM Trusted Firmware
1549
1550 For kernels that have this configuration enabled but boot with broken
1551 firmware, you may need to say N here until the firmware is fixed.
1552 Otherwise you may experience firmware panics or lockups when
1553 accessing the counter registers. Even if you are not observing these
1554 symptoms, the values returned by the register reads might not
1555 correctly reflect reality. Most commonly, the value read will be 0,
1556 indicating that the counter is not enabled.
1557
1558config AS_HAS_ARMV8_4
1559 def_bool $(cc-option,-Wa$(comma)-march=armv8.4-a)
1560
1561config ARM64_TLB_RANGE
1562 bool "Enable support for tlbi range feature"
1563 default y
1564 depends on AS_HAS_ARMV8_4
1565 help
1566 ARMv8.4-TLBI provides TLBI invalidation instruction that apply to a
1567 range of input addresses.
1568
1569 The feature introduces new assembly instructions, and they were
1570 support when binutils >= 2.30.
1571
1572endmenu
1573
1574menu "ARMv8.5 architectural features"
1575
1576config AS_HAS_ARMV8_5
1577 def_bool $(cc-option,-Wa$(comma)-march=armv8.5-a)
1578
1579config ARM64_BTI
1580 bool "Branch Target Identification support"
1581 default y
1582 help
1583 Branch Target Identification (part of the ARMv8.5 Extensions)
1584 provides a mechanism to limit the set of locations to which computed
1585 branch instructions such as BR or BLR can jump.
1586
1587 To make use of BTI on CPUs that support it, say Y.
1588
1589 BTI is intended to provide complementary protection to other control
1590 flow integrity protection mechanisms, such as the Pointer
1591 authentication mechanism provided as part of the ARMv8.3 Extensions.
1592 For this reason, it does not make sense to enable this option without
1593 also enabling support for pointer authentication. Thus, when
1594 enabling this option you should also select ARM64_PTR_AUTH=y.
1595
1596 Userspace binaries must also be specifically compiled to make use of
1597 this mechanism. If you say N here or the hardware does not support
1598 BTI, such binaries can still run, but you get no additional
1599 enforcement of branch destinations.
1600
1601config ARM64_BTI_KERNEL
1602 bool "Use Branch Target Identification for kernel"
1603 default y
1604 depends on ARM64_BTI
1605 depends on ARM64_PTR_AUTH_KERNEL
1606 depends on CC_HAS_BRANCH_PROT_PAC_RET_BTI
1607 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94697
1608 depends on !CC_IS_GCC || GCC_VERSION >= 100100
1609 # https://github.com/llvm/llvm-project/commit/a88c722e687e6780dcd6a58718350dc76fcc4cc9
1610 depends on !CC_IS_CLANG || CLANG_VERSION >= 120000
1611 depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS)
1612 help
1613 Build the kernel with Branch Target Identification annotations
1614 and enable enforcement of this for kernel code. When this option
1615 is enabled and the system supports BTI all kernel code including
1616 modular code must have BTI enabled.
1617
1618config CC_HAS_BRANCH_PROT_PAC_RET_BTI
1619 # GCC 9 or later, clang 8 or later
1620 def_bool $(cc-option,-mbranch-protection=pac-ret+leaf+bti)
1621
1622config ARM64_E0PD
1623 bool "Enable support for E0PD"
1624 default y
1625 help
1626 E0PD (part of the ARMv8.5 extensions) allows us to ensure
1627 that EL0 accesses made via TTBR1 always fault in constant time,
1628 providing similar benefits to KASLR as those provided by KPTI, but
1629 with lower overhead and without disrupting legitimate access to
1630 kernel memory such as SPE.
1631
1632 This option enables E0PD for TTBR1 where available.
1633
1634config ARCH_RANDOM
1635 bool "Enable support for random number generation"
1636 default y
1637 help
1638 Random number generation (part of the ARMv8.5 Extensions)
1639 provides a high bandwidth, cryptographically secure
1640 hardware random number generator.
1641
1642config ARM64_AS_HAS_MTE
1643 # Initial support for MTE went in binutils 2.32.0, checked with
1644 # ".arch armv8.5-a+memtag" below. However, this was incomplete
1645 # as a late addition to the final architecture spec (LDGM/STGM)
1646 # is only supported in the newer 2.32.x and 2.33 binutils
1647 # versions, hence the extra "stgm" instruction check below.
1648 def_bool $(as-instr,.arch armv8.5-a+memtag\nstgm xzr$(comma)[x0])
1649
1650config ARM64_MTE
1651 bool "Memory Tagging Extension support"
1652 default y
1653 depends on ARM64_AS_HAS_MTE && ARM64_TAGGED_ADDR_ABI
1654 depends on AS_HAS_ARMV8_5
1655 depends on AS_HAS_LSE_ATOMICS
1656 # Required for tag checking in the uaccess routines
1657 depends on ARM64_PAN
1658 select ARCH_USES_HIGH_VMA_FLAGS
1659 help
1660 Memory Tagging (part of the ARMv8.5 Extensions) provides
1661 architectural support for run-time, always-on detection of
1662 various classes of memory error to aid with software debugging
1663 to eliminate vulnerabilities arising from memory-unsafe
1664 languages.
1665
1666 This option enables the support for the Memory Tagging
1667 Extension at EL0 (i.e. for userspace).
1668
1669 Selecting this option allows the feature to be detected at
1670 runtime. Any secondary CPU not implementing this feature will
1671 not be allowed a late bring-up.
1672
1673 Userspace binaries that want to use this feature must
1674 explicitly opt in. The mechanism for the userspace is
1675 described in:
1676
1677 Documentation/arm64/memory-tagging-extension.rst.
1678
1679endmenu
1680
1681menu "ARMv8.7 architectural features"
1682
1683config ARM64_EPAN
1684 bool "Enable support for Enhanced Privileged Access Never (EPAN)"
1685 default y
1686 depends on ARM64_PAN
1687 help
1688 Enhanced Privileged Access Never (EPAN) allows Privileged
1689 Access Never to be used with Execute-only mappings.
1690
1691 The feature is detected at runtime, and will remain disabled
1692 if the cpu does not implement the feature.
1693endmenu
1694
1695config ARM64_SVE
1696 bool "ARM Scalable Vector Extension support"
1697 default y
1698 help
1699 The Scalable Vector Extension (SVE) is an extension to the AArch64
1700 execution state which complements and extends the SIMD functionality
1701 of the base architecture to support much larger vectors and to enable
1702 additional vectorisation opportunities.
1703
1704 To enable use of this extension on CPUs that implement it, say Y.
1705
1706 On CPUs that support the SVE2 extensions, this option will enable
1707 those too.
1708
1709 Note that for architectural reasons, firmware _must_ implement SVE
1710 support when running on SVE capable hardware. The required support
1711 is present in:
1712
1713 * version 1.5 and later of the ARM Trusted Firmware
1714 * the AArch64 boot wrapper since commit 5e1261e08abf
1715 ("bootwrapper: SVE: Enable SVE for EL2 and below").
1716
1717 For other firmware implementations, consult the firmware documentation
1718 or vendor.
1719
1720 If you need the kernel to boot on SVE-capable hardware with broken
1721 firmware, you may need to say N here until you get your firmware
1722 fixed. Otherwise, you may experience firmware panics or lockups when
1723 booting the kernel. If unsure and you are not observing these
1724 symptoms, you should assume that it is safe to say Y.
1725
1726config ARM64_MODULE_PLTS
1727 bool "Use PLTs to allow module memory to spill over into vmalloc area"
1728 depends on MODULES
1729 select HAVE_MOD_ARCH_SPECIFIC
1730 help
1731 Allocate PLTs when loading modules so that jumps and calls whose
1732 targets are too far away for their relative offsets to be encoded
1733 in the instructions themselves can be bounced via veneers in the
1734 module's PLT. This allows modules to be allocated in the generic
1735 vmalloc area after the dedicated module memory area has been
1736 exhausted.
1737
1738 When running with address space randomization (KASLR), the module
1739 region itself may be too far away for ordinary relative jumps and
1740 calls, and so in that case, module PLTs are required and cannot be
1741 disabled.
1742
1743 Specific errata workaround(s) might also force module PLTs to be
1744 enabled (ARM64_ERRATUM_843419).
1745
1746config ARM64_PSEUDO_NMI
1747 bool "Support for NMI-like interrupts"
1748 select ARM_GIC_V3
1749 help
1750 Adds support for mimicking Non-Maskable Interrupts through the use of
1751 GIC interrupt priority. This support requires version 3 or later of
1752 ARM GIC.
1753
1754 This high priority configuration for interrupts needs to be
1755 explicitly enabled by setting the kernel parameter
1756 "irqchip.gicv3_pseudo_nmi" to 1.
1757
1758 If unsure, say N
1759
1760if ARM64_PSEUDO_NMI
1761config ARM64_DEBUG_PRIORITY_MASKING
1762 bool "Debug interrupt priority masking"
1763 help
1764 This adds runtime checks to functions enabling/disabling
1765 interrupts when using priority masking. The additional checks verify
1766 the validity of ICC_PMR_EL1 when calling concerned functions.
1767
1768 If unsure, say N
1769endif
1770
1771config RELOCATABLE
1772 bool "Build a relocatable kernel image" if EXPERT
1773 select ARCH_HAS_RELR
1774 default y
1775 help
1776 This builds the kernel as a Position Independent Executable (PIE),
1777 which retains all relocation metadata required to relocate the
1778 kernel binary at runtime to a different virtual address than the
1779 address it was linked at.
1780 Since AArch64 uses the RELA relocation format, this requires a
1781 relocation pass at runtime even if the kernel is loaded at the
1782 same address it was linked at.
1783
1784config RANDOMIZE_BASE
1785 bool "Randomize the address of the kernel image"
1786 select ARM64_MODULE_PLTS if MODULES
1787 select RELOCATABLE
1788 help
1789 Randomizes the virtual address at which the kernel image is
1790 loaded, as a security feature that deters exploit attempts
1791 relying on knowledge of the location of kernel internals.
1792
1793 It is the bootloader's job to provide entropy, by passing a
1794 random u64 value in /chosen/kaslr-seed at kernel entry.
1795
1796 When booting via the UEFI stub, it will invoke the firmware's
1797 EFI_RNG_PROTOCOL implementation (if available) to supply entropy
1798 to the kernel proper. In addition, it will randomise the physical
1799 location of the kernel Image as well.
1800
1801 If unsure, say N.
1802
1803config RANDOMIZE_MODULE_REGION_FULL
1804 bool "Randomize the module region over a 2 GB range"
1805 depends on RANDOMIZE_BASE
1806 default y
1807 help
1808 Randomizes the location of the module region inside a 2 GB window
1809 covering the core kernel. This way, it is less likely for modules
1810 to leak information about the location of core kernel data structures
1811 but it does imply that function calls between modules and the core
1812 kernel will need to be resolved via veneers in the module PLT.
1813
1814 When this option is not set, the module region will be randomized over
1815 a limited range that contains the [_stext, _etext] interval of the
1816 core kernel, so branch relocations are almost always in range unless
1817 ARM64_MODULE_PLTS is enabled and the region is exhausted. In this
1818 particular case of region exhaustion, modules might be able to fall
1819 back to a larger 2GB area.
1820
1821config CC_HAVE_STACKPROTECTOR_SYSREG
1822 def_bool $(cc-option,-mstack-protector-guard=sysreg -mstack-protector-guard-reg=sp_el0 -mstack-protector-guard-offset=0)
1823
1824config STACKPROTECTOR_PER_TASK
1825 def_bool y
1826 depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_SYSREG
1827
1828endmenu
1829
1830menu "Boot options"
1831
1832config ARM64_ACPI_PARKING_PROTOCOL
1833 bool "Enable support for the ARM64 ACPI parking protocol"
1834 depends on ACPI
1835 help
1836 Enable support for the ARM64 ACPI parking protocol. If disabled
1837 the kernel will not allow booting through the ARM64 ACPI parking
1838 protocol even if the corresponding data is present in the ACPI
1839 MADT table.
1840
1841config CMDLINE
1842 string "Default kernel command string"
1843 default ""
1844 help
1845 Provide a set of default command-line options at build time by
1846 entering them here. As a minimum, you should specify the the
1847 root device (e.g. root=/dev/nfs).
1848
1849choice
1850 prompt "Kernel command line type" if CMDLINE != ""
1851 default CMDLINE_FROM_BOOTLOADER
1852 help
1853 Choose how the kernel will handle the provided default kernel
1854 command line string.
1855
1856config CMDLINE_FROM_BOOTLOADER
1857 bool "Use bootloader kernel arguments if available"
1858 help
1859 Uses the command-line options passed by the boot loader. If
1860 the boot loader doesn't provide any, the default kernel command
1861 string provided in CMDLINE will be used.
1862
1863config CMDLINE_FORCE
1864 bool "Always use the default kernel command string"
1865 help
1866 Always use the default kernel command string, even if the boot
1867 loader passes other arguments to the kernel.
1868 This is useful if you cannot or don't want to change the
1869 command-line options your boot loader passes to the kernel.
1870
1871endchoice
1872
1873config EFI_STUB
1874 bool
1875
1876config EFI
1877 bool "UEFI runtime support"
1878 depends on OF && !CPU_BIG_ENDIAN
1879 depends on KERNEL_MODE_NEON
1880 select ARCH_SUPPORTS_ACPI
1881 select LIBFDT
1882 select UCS2_STRING
1883 select EFI_PARAMS_FROM_FDT
1884 select EFI_RUNTIME_WRAPPERS
1885 select EFI_STUB
1886 select EFI_GENERIC_STUB
1887 imply IMA_SECURE_AND_OR_TRUSTED_BOOT
1888 default y
1889 help
1890 This option provides support for runtime services provided
1891 by UEFI firmware (such as non-volatile variables, realtime
1892 clock, and platform reset). A UEFI stub is also provided to
1893 allow the kernel to be booted as an EFI application. This
1894 is only useful on systems that have UEFI firmware.
1895
1896config DMI
1897 bool "Enable support for SMBIOS (DMI) tables"
1898 depends on EFI
1899 default y
1900 help
1901 This enables SMBIOS/DMI feature for systems.
1902
1903 This option is only useful on systems that have UEFI firmware.
1904 However, even with this option, the resultant kernel should
1905 continue to boot on existing non-UEFI platforms.
1906
1907endmenu
1908
1909config SYSVIPC_COMPAT
1910 def_bool y
1911 depends on COMPAT && SYSVIPC
1912
1913menu "Power management options"
1914
1915source "kernel/power/Kconfig"
1916
1917config ARCH_HIBERNATION_POSSIBLE
1918 def_bool y
1919 depends on CPU_PM
1920
1921config ARCH_HIBERNATION_HEADER
1922 def_bool y
1923 depends on HIBERNATION
1924
1925config ARCH_SUSPEND_POSSIBLE
1926 def_bool y
1927
1928endmenu
1929
1930menu "CPU Power Management"
1931
1932source "drivers/cpuidle/Kconfig"
1933
1934source "drivers/cpufreq/Kconfig"
1935
1936endmenu
1937
1938source "drivers/firmware/Kconfig"
1939
1940source "drivers/acpi/Kconfig"
1941
1942source "arch/arm64/kvm/Kconfig"
1943
1944if CRYPTO
1945source "arch/arm64/crypto/Kconfig"
1946endif