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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 *
6 * Enhanced CPU detection and feature setting code by Mike Jagdis
7 * and Martin Mares, November 1997.
8 */
9
10.text
11#include <linux/threads.h>
12#include <linux/init.h>
13#include <linux/linkage.h>
14#include <asm/segment.h>
15#include <asm/page_types.h>
16#include <asm/pgtable_types.h>
17#include <asm/cache.h>
18#include <asm/thread_info.h>
19#include <asm/asm-offsets.h>
20#include <asm/setup.h>
21#include <asm/processor-flags.h>
22#include <asm/msr-index.h>
23#include <asm/cpufeatures.h>
24#include <asm/percpu.h>
25#include <asm/nops.h>
26#include <asm/nospec-branch.h>
27#include <asm/bootparam.h>
28#include <asm/export.h>
29#include <asm/pgtable_32.h>
30
31/* Physical address */
32#define pa(X) ((X) - __PAGE_OFFSET)
33
34/*
35 * References to members of the new_cpu_data structure.
36 */
37
38#define X86 new_cpu_data+CPUINFO_x86
39#define X86_VENDOR new_cpu_data+CPUINFO_x86_vendor
40#define X86_MODEL new_cpu_data+CPUINFO_x86_model
41#define X86_STEPPING new_cpu_data+CPUINFO_x86_stepping
42#define X86_HARD_MATH new_cpu_data+CPUINFO_hard_math
43#define X86_CPUID new_cpu_data+CPUINFO_cpuid_level
44#define X86_CAPABILITY new_cpu_data+CPUINFO_x86_capability
45#define X86_VENDOR_ID new_cpu_data+CPUINFO_x86_vendor_id
46
47
48#define SIZEOF_PTREGS 17*4
49
50/*
51 * Worst-case size of the kernel mapping we need to make:
52 * a relocatable kernel can live anywhere in lowmem, so we need to be able
53 * to map all of lowmem.
54 */
55KERNEL_PAGES = LOWMEM_PAGES
56
57INIT_MAP_SIZE = PAGE_TABLE_SIZE(KERNEL_PAGES) * PAGE_SIZE
58RESERVE_BRK(pagetables, INIT_MAP_SIZE)
59
60/*
61 * 32-bit kernel entrypoint; only used by the boot CPU. On entry,
62 * %esi points to the real-mode code as a 32-bit pointer.
63 * CS and DS must be 4 GB flat segments, but we don't depend on
64 * any particular GDT layout, because we load our own as soon as we
65 * can.
66 */
67__HEAD
68SYM_CODE_START(startup_32)
69 movl pa(initial_stack),%ecx
70
71/*
72 * Set segments to known values.
73 */
74 lgdt pa(boot_gdt_descr)
75 movl $(__BOOT_DS),%eax
76 movl %eax,%ds
77 movl %eax,%es
78 movl %eax,%fs
79 movl %eax,%gs
80 movl %eax,%ss
81 leal -__PAGE_OFFSET(%ecx),%esp
82
83/*
84 * Clear BSS first so that there are no surprises...
85 */
86 cld
87 xorl %eax,%eax
88 movl $pa(__bss_start),%edi
89 movl $pa(__bss_stop),%ecx
90 subl %edi,%ecx
91 shrl $2,%ecx
92 rep ; stosl
93/*
94 * Copy bootup parameters out of the way.
95 * Note: %esi still has the pointer to the real-mode data.
96 * With the kexec as boot loader, parameter segment might be loaded beyond
97 * kernel image and might not even be addressable by early boot page tables.
98 * (kexec on panic case). Hence copy out the parameters before initializing
99 * page tables.
100 */
101 movl $pa(boot_params),%edi
102 movl $(PARAM_SIZE/4),%ecx
103 cld
104 rep
105 movsl
106 movl pa(boot_params) + NEW_CL_POINTER,%esi
107 andl %esi,%esi
108 jz 1f # No command line
109 movl $pa(boot_command_line),%edi
110 movl $(COMMAND_LINE_SIZE/4),%ecx
111 rep
112 movsl
1131:
114
115#ifdef CONFIG_OLPC
116 /* save OFW's pgdir table for later use when calling into OFW */
117 movl %cr3, %eax
118 movl %eax, pa(olpc_ofw_pgd)
119#endif
120
121#ifdef CONFIG_MICROCODE
122 /* Early load ucode on BSP. */
123 call load_ucode_bsp
124#endif
125
126 /* Create early pagetables. */
127 call mk_early_pgtbl_32
128
129 /* Do early initialization of the fixmap area */
130 movl $pa(initial_pg_fixmap)+PDE_IDENT_ATTR,%eax
131#ifdef CONFIG_X86_PAE
132#define KPMDS (((-__PAGE_OFFSET) >> 30) & 3) /* Number of kernel PMDs */
133 movl %eax,pa(initial_pg_pmd+0x1000*KPMDS-8)
134#else
135 movl %eax,pa(initial_page_table+0xffc)
136#endif
137
138 jmp .Ldefault_entry
139SYM_CODE_END(startup_32)
140
141#ifdef CONFIG_HOTPLUG_CPU
142/*
143 * Boot CPU0 entry point. It's called from play_dead(). Everything has been set
144 * up already except stack. We just set up stack here. Then call
145 * start_secondary().
146 */
147SYM_FUNC_START(start_cpu0)
148 movl initial_stack, %ecx
149 movl %ecx, %esp
150 call *(initial_code)
1511: jmp 1b
152SYM_FUNC_END(start_cpu0)
153#endif
154
155/*
156 * Non-boot CPU entry point; entered from trampoline.S
157 * We can't lgdt here, because lgdt itself uses a data segment, but
158 * we know the trampoline has already loaded the boot_gdt for us.
159 *
160 * If cpu hotplug is not supported then this code can go in init section
161 * which will be freed later
162 */
163SYM_FUNC_START(startup_32_smp)
164 cld
165 movl $(__BOOT_DS),%eax
166 movl %eax,%ds
167 movl %eax,%es
168 movl %eax,%fs
169 movl %eax,%gs
170 movl pa(initial_stack),%ecx
171 movl %eax,%ss
172 leal -__PAGE_OFFSET(%ecx),%esp
173
174#ifdef CONFIG_MICROCODE
175 /* Early load ucode on AP. */
176 call load_ucode_ap
177#endif
178
179.Ldefault_entry:
180 movl $(CR0_STATE & ~X86_CR0_PG),%eax
181 movl %eax,%cr0
182
183/*
184 * We want to start out with EFLAGS unambiguously cleared. Some BIOSes leave
185 * bits like NT set. This would confuse the debugger if this code is traced. So
186 * initialize them properly now before switching to protected mode. That means
187 * DF in particular (even though we have cleared it earlier after copying the
188 * command line) because GCC expects it.
189 */
190 pushl $0
191 popfl
192
193/*
194 * New page tables may be in 4Mbyte page mode and may be using the global pages.
195 *
196 * NOTE! If we are on a 486 we may have no cr4 at all! Specifically, cr4 exists
197 * if and only if CPUID exists and has flags other than the FPU flag set.
198 */
199 movl $-1,pa(X86_CPUID) # preset CPUID level
200 movl $X86_EFLAGS_ID,%ecx
201 pushl %ecx
202 popfl # set EFLAGS=ID
203 pushfl
204 popl %eax # get EFLAGS
205 testl $X86_EFLAGS_ID,%eax # did EFLAGS.ID remained set?
206 jz .Lenable_paging # hw disallowed setting of ID bit
207 # which means no CPUID and no CR4
208
209 xorl %eax,%eax
210 cpuid
211 movl %eax,pa(X86_CPUID) # save largest std CPUID function
212
213 movl $1,%eax
214 cpuid
215 andl $~1,%edx # Ignore CPUID.FPU
216 jz .Lenable_paging # No flags or only CPUID.FPU = no CR4
217
218 movl pa(mmu_cr4_features),%eax
219 movl %eax,%cr4
220
221 testb $X86_CR4_PAE, %al # check if PAE is enabled
222 jz .Lenable_paging
223
224 /* Check if extended functions are implemented */
225 movl $0x80000000, %eax
226 cpuid
227 /* Value must be in the range 0x80000001 to 0x8000ffff */
228 subl $0x80000001, %eax
229 cmpl $(0x8000ffff-0x80000001), %eax
230 ja .Lenable_paging
231
232 /* Clear bogus XD_DISABLE bits */
233 call verify_cpu
234
235 mov $0x80000001, %eax
236 cpuid
237 /* Execute Disable bit supported? */
238 btl $(X86_FEATURE_NX & 31), %edx
239 jnc .Lenable_paging
240
241 /* Setup EFER (Extended Feature Enable Register) */
242 movl $MSR_EFER, %ecx
243 rdmsr
244
245 btsl $_EFER_NX, %eax
246 /* Make changes effective */
247 wrmsr
248
249.Lenable_paging:
250
251/*
252 * Enable paging
253 */
254 movl $pa(initial_page_table), %eax
255 movl %eax,%cr3 /* set the page table pointer.. */
256 movl $CR0_STATE,%eax
257 movl %eax,%cr0 /* ..and set paging (PG) bit */
258 ljmp $__BOOT_CS,$1f /* Clear prefetch and normalize %eip */
2591:
260 /* Shift the stack pointer to a virtual address */
261 addl $__PAGE_OFFSET, %esp
262
263/*
264 * Check if it is 486
265 */
266 movb $4,X86 # at least 486
267 cmpl $-1,X86_CPUID
268 je .Lis486
269
270 /* get vendor info */
271 xorl %eax,%eax # call CPUID with 0 -> return vendor ID
272 cpuid
273 movl %eax,X86_CPUID # save CPUID level
274 movl %ebx,X86_VENDOR_ID # lo 4 chars
275 movl %edx,X86_VENDOR_ID+4 # next 4 chars
276 movl %ecx,X86_VENDOR_ID+8 # last 4 chars
277
278 orl %eax,%eax # do we have processor info as well?
279 je .Lis486
280
281 movl $1,%eax # Use the CPUID instruction to get CPU type
282 cpuid
283 movb %al,%cl # save reg for future use
284 andb $0x0f,%ah # mask processor family
285 movb %ah,X86
286 andb $0xf0,%al # mask model
287 shrb $4,%al
288 movb %al,X86_MODEL
289 andb $0x0f,%cl # mask mask revision
290 movb %cl,X86_STEPPING
291 movl %edx,X86_CAPABILITY
292
293.Lis486:
294 movl $0x50022,%ecx # set AM, WP, NE and MP
295 movl %cr0,%eax
296 andl $0x80000011,%eax # Save PG,PE,ET
297 orl %ecx,%eax
298 movl %eax,%cr0
299
300 lgdt early_gdt_descr
301 ljmp $(__KERNEL_CS),$1f
3021: movl $(__KERNEL_DS),%eax # reload all the segment registers
303 movl %eax,%ss # after changing gdt.
304
305 movl $(__USER_DS),%eax # DS/ES contains default USER segment
306 movl %eax,%ds
307 movl %eax,%es
308
309 movl $(__KERNEL_PERCPU), %eax
310 movl %eax,%fs # set this cpu's percpu
311
312 xorl %eax,%eax
313 movl %eax,%gs # clear possible garbage in %gs
314
315 xorl %eax,%eax # Clear LDT
316 lldt %ax
317
318 call *(initial_code)
3191: jmp 1b
320SYM_FUNC_END(startup_32_smp)
321
322#include "verify_cpu.S"
323
324__INIT
325SYM_FUNC_START(early_idt_handler_array)
326 # 36(%esp) %eflags
327 # 32(%esp) %cs
328 # 28(%esp) %eip
329 # 24(%rsp) error code
330 i = 0
331 .rept NUM_EXCEPTION_VECTORS
332 .if ((EXCEPTION_ERRCODE_MASK >> i) & 1) == 0
333 pushl $0 # Dummy error code, to make stack frame uniform
334 .endif
335 pushl $i # 20(%esp) Vector number
336 jmp early_idt_handler_common
337 i = i + 1
338 .fill early_idt_handler_array + i*EARLY_IDT_HANDLER_SIZE - ., 1, 0xcc
339 .endr
340SYM_FUNC_END(early_idt_handler_array)
341
342SYM_CODE_START_LOCAL(early_idt_handler_common)
343 /*
344 * The stack is the hardware frame, an error code or zero, and the
345 * vector number.
346 */
347 cld
348
349 incl %ss:early_recursion_flag
350
351 /* The vector number is in pt_regs->gs */
352
353 cld
354 pushl %fs /* pt_regs->fs (__fsh varies by model) */
355 pushl %es /* pt_regs->es (__esh varies by model) */
356 pushl %ds /* pt_regs->ds (__dsh varies by model) */
357 pushl %eax /* pt_regs->ax */
358 pushl %ebp /* pt_regs->bp */
359 pushl %edi /* pt_regs->di */
360 pushl %esi /* pt_regs->si */
361 pushl %edx /* pt_regs->dx */
362 pushl %ecx /* pt_regs->cx */
363 pushl %ebx /* pt_regs->bx */
364
365 /* Fix up DS and ES */
366 movl $(__KERNEL_DS), %ecx
367 movl %ecx, %ds
368 movl %ecx, %es
369
370 /* Load the vector number into EDX */
371 movl PT_GS(%esp), %edx
372
373 /* Load GS into pt_regs->gs (and maybe clobber __gsh) */
374 movw %gs, PT_GS(%esp)
375
376 movl %esp, %eax /* args are pt_regs (EAX), trapnr (EDX) */
377 call early_fixup_exception
378
379 popl %ebx /* pt_regs->bx */
380 popl %ecx /* pt_regs->cx */
381 popl %edx /* pt_regs->dx */
382 popl %esi /* pt_regs->si */
383 popl %edi /* pt_regs->di */
384 popl %ebp /* pt_regs->bp */
385 popl %eax /* pt_regs->ax */
386 popl %ds /* pt_regs->ds (always ignores __dsh) */
387 popl %es /* pt_regs->es (always ignores __esh) */
388 popl %fs /* pt_regs->fs (always ignores __fsh) */
389 popl %gs /* pt_regs->gs (always ignores __gsh) */
390 decl %ss:early_recursion_flag
391 addl $4, %esp /* pop pt_regs->orig_ax */
392 iret
393SYM_CODE_END(early_idt_handler_common)
394
395/* This is the default interrupt "handler" :-) */
396SYM_FUNC_START(early_ignore_irq)
397 cld
398#ifdef CONFIG_PRINTK
399 pushl %eax
400 pushl %ecx
401 pushl %edx
402 pushl %es
403 pushl %ds
404 movl $(__KERNEL_DS),%eax
405 movl %eax,%ds
406 movl %eax,%es
407 cmpl $2,early_recursion_flag
408 je hlt_loop
409 incl early_recursion_flag
410 pushl 16(%esp)
411 pushl 24(%esp)
412 pushl 32(%esp)
413 pushl 40(%esp)
414 pushl $int_msg
415 call _printk
416
417 call dump_stack
418
419 addl $(5*4),%esp
420 popl %ds
421 popl %es
422 popl %edx
423 popl %ecx
424 popl %eax
425#endif
426 iret
427
428hlt_loop:
429 hlt
430 jmp hlt_loop
431SYM_FUNC_END(early_ignore_irq)
432
433__INITDATA
434 .align 4
435SYM_DATA(early_recursion_flag, .long 0)
436
437__REFDATA
438 .align 4
439SYM_DATA(initial_code, .long i386_start_kernel)
440
441#ifdef CONFIG_PAGE_TABLE_ISOLATION
442#define PGD_ALIGN (2 * PAGE_SIZE)
443#define PTI_USER_PGD_FILL 1024
444#else
445#define PGD_ALIGN (PAGE_SIZE)
446#define PTI_USER_PGD_FILL 0
447#endif
448/*
449 * BSS section
450 */
451__PAGE_ALIGNED_BSS
452 .align PGD_ALIGN
453#ifdef CONFIG_X86_PAE
454.globl initial_pg_pmd
455initial_pg_pmd:
456 .fill 1024*KPMDS,4,0
457#else
458.globl initial_page_table
459initial_page_table:
460 .fill 1024,4,0
461#endif
462 .align PGD_ALIGN
463initial_pg_fixmap:
464 .fill 1024,4,0
465.globl swapper_pg_dir
466 .align PGD_ALIGN
467swapper_pg_dir:
468 .fill 1024,4,0
469 .fill PTI_USER_PGD_FILL,4,0
470.globl empty_zero_page
471empty_zero_page:
472 .fill 4096,1,0
473EXPORT_SYMBOL(empty_zero_page)
474
475/*
476 * This starts the data section.
477 */
478#ifdef CONFIG_X86_PAE
479__PAGE_ALIGNED_DATA
480 /* Page-aligned for the benefit of paravirt? */
481 .align PGD_ALIGN
482SYM_DATA_START(initial_page_table)
483 .long pa(initial_pg_pmd+PGD_IDENT_ATTR),0 /* low identity map */
484# if KPMDS == 3
485 .long pa(initial_pg_pmd+PGD_IDENT_ATTR),0
486 .long pa(initial_pg_pmd+PGD_IDENT_ATTR+0x1000),0
487 .long pa(initial_pg_pmd+PGD_IDENT_ATTR+0x2000),0
488# elif KPMDS == 2
489 .long 0,0
490 .long pa(initial_pg_pmd+PGD_IDENT_ATTR),0
491 .long pa(initial_pg_pmd+PGD_IDENT_ATTR+0x1000),0
492# elif KPMDS == 1
493 .long 0,0
494 .long 0,0
495 .long pa(initial_pg_pmd+PGD_IDENT_ATTR),0
496# else
497# error "Kernel PMDs should be 1, 2 or 3"
498# endif
499 .align PAGE_SIZE /* needs to be page-sized too */
500
501#ifdef CONFIG_PAGE_TABLE_ISOLATION
502 /*
503 * PTI needs another page so sync_initial_pagetable() works correctly
504 * and does not scribble over the data which is placed behind the
505 * actual initial_page_table. See clone_pgd_range().
506 */
507 .fill 1024, 4, 0
508#endif
509
510SYM_DATA_END(initial_page_table)
511#endif
512
513.data
514.balign 4
515/*
516 * The SIZEOF_PTREGS gap is a convention which helps the in-kernel unwinder
517 * reliably detect the end of the stack.
518 */
519SYM_DATA(initial_stack,
520 .long init_thread_union + THREAD_SIZE -
521 SIZEOF_PTREGS - TOP_OF_KERNEL_STACK_PADDING)
522
523__INITRODATA
524int_msg:
525 .asciz "Unknown interrupt or fault at: %p %p %p\n"
526
527#include "../../x86/xen/xen-head.S"
528
529/*
530 * The IDT and GDT 'descriptors' are a strange 48-bit object
531 * only used by the lidt and lgdt instructions. They are not
532 * like usual segment descriptors - they consist of a 16-bit
533 * segment size, and 32-bit linear address value:
534 */
535
536 .data
537 ALIGN
538# early boot GDT descriptor (must use 1:1 address mapping)
539 .word 0 # 32 bit align gdt_desc.address
540SYM_DATA_START_LOCAL(boot_gdt_descr)
541 .word __BOOT_DS+7
542 .long boot_gdt - __PAGE_OFFSET
543SYM_DATA_END(boot_gdt_descr)
544
545# boot GDT descriptor (later on used by CPU#0):
546 .word 0 # 32 bit align gdt_desc.address
547SYM_DATA_START(early_gdt_descr)
548 .word GDT_ENTRIES*8-1
549 .long gdt_page /* Overwritten for secondary CPUs */
550SYM_DATA_END(early_gdt_descr)
551
552/*
553 * The boot_gdt must mirror the equivalent in setup.S and is
554 * used only for booting.
555 */
556 .align L1_CACHE_BYTES
557SYM_DATA_START(boot_gdt)
558 .fill GDT_ENTRY_BOOT_CS,8,0
559 .quad 0x00cf9a000000ffff /* kernel 4GB code at 0x00000000 */
560 .quad 0x00cf92000000ffff /* kernel 4GB data at 0x00000000 */
561SYM_DATA_END(boot_gdt)
1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 *
6 * Enhanced CPU detection and feature setting code by Mike Jagdis
7 * and Martin Mares, November 1997.
8 */
9
10.text
11#include <linux/threads.h>
12#include <linux/init.h>
13#include <linux/linkage.h>
14#include <asm/segment.h>
15#include <asm/page_types.h>
16#include <asm/pgtable_types.h>
17#include <asm/cache.h>
18#include <asm/thread_info.h>
19#include <asm/asm-offsets.h>
20#include <asm/setup.h>
21#include <asm/processor-flags.h>
22#include <asm/msr-index.h>
23#include <asm/cpufeatures.h>
24#include <asm/percpu.h>
25#include <asm/nops.h>
26#include <asm/bootparam.h>
27#include <asm/export.h>
28#include <asm/pgtable_32.h>
29
30/* Physical address */
31#define pa(X) ((X) - __PAGE_OFFSET)
32
33/*
34 * References to members of the new_cpu_data structure.
35 */
36
37#define X86 new_cpu_data+CPUINFO_x86
38#define X86_VENDOR new_cpu_data+CPUINFO_x86_vendor
39#define X86_MODEL new_cpu_data+CPUINFO_x86_model
40#define X86_STEPPING new_cpu_data+CPUINFO_x86_stepping
41#define X86_HARD_MATH new_cpu_data+CPUINFO_hard_math
42#define X86_CPUID new_cpu_data+CPUINFO_cpuid_level
43#define X86_CAPABILITY new_cpu_data+CPUINFO_x86_capability
44#define X86_VENDOR_ID new_cpu_data+CPUINFO_x86_vendor_id
45
46
47#define SIZEOF_PTREGS 17*4
48
49/*
50 * Worst-case size of the kernel mapping we need to make:
51 * a relocatable kernel can live anywhere in lowmem, so we need to be able
52 * to map all of lowmem.
53 */
54KERNEL_PAGES = LOWMEM_PAGES
55
56INIT_MAP_SIZE = PAGE_TABLE_SIZE(KERNEL_PAGES) * PAGE_SIZE
57RESERVE_BRK(pagetables, INIT_MAP_SIZE)
58
59/*
60 * 32-bit kernel entrypoint; only used by the boot CPU. On entry,
61 * %esi points to the real-mode code as a 32-bit pointer.
62 * CS and DS must be 4 GB flat segments, but we don't depend on
63 * any particular GDT layout, because we load our own as soon as we
64 * can.
65 */
66__HEAD
67SYM_CODE_START(startup_32)
68 movl pa(initial_stack),%ecx
69
70/*
71 * Set segments to known values.
72 */
73 lgdt pa(boot_gdt_descr)
74 movl $(__BOOT_DS),%eax
75 movl %eax,%ds
76 movl %eax,%es
77 movl %eax,%fs
78 movl %eax,%gs
79 movl %eax,%ss
80 leal -__PAGE_OFFSET(%ecx),%esp
81
82/*
83 * Clear BSS first so that there are no surprises...
84 */
85 cld
86 xorl %eax,%eax
87 movl $pa(__bss_start),%edi
88 movl $pa(__bss_stop),%ecx
89 subl %edi,%ecx
90 shrl $2,%ecx
91 rep ; stosl
92/*
93 * Copy bootup parameters out of the way.
94 * Note: %esi still has the pointer to the real-mode data.
95 * With the kexec as boot loader, parameter segment might be loaded beyond
96 * kernel image and might not even be addressable by early boot page tables.
97 * (kexec on panic case). Hence copy out the parameters before initializing
98 * page tables.
99 */
100 movl $pa(boot_params),%edi
101 movl $(PARAM_SIZE/4),%ecx
102 cld
103 rep
104 movsl
105 movl pa(boot_params) + NEW_CL_POINTER,%esi
106 andl %esi,%esi
107 jz 1f # No command line
108 movl $pa(boot_command_line),%edi
109 movl $(COMMAND_LINE_SIZE/4),%ecx
110 rep
111 movsl
1121:
113
114#ifdef CONFIG_OLPC
115 /* save OFW's pgdir table for later use when calling into OFW */
116 movl %cr3, %eax
117 movl %eax, pa(olpc_ofw_pgd)
118#endif
119
120#ifdef CONFIG_MICROCODE
121 /* Early load ucode on BSP. */
122 call load_ucode_bsp
123#endif
124
125 /* Create early pagetables. */
126 call mk_early_pgtbl_32
127
128 /* Do early initialization of the fixmap area */
129 movl $pa(initial_pg_fixmap)+PDE_IDENT_ATTR,%eax
130#ifdef CONFIG_X86_PAE
131#define KPMDS (((-__PAGE_OFFSET) >> 30) & 3) /* Number of kernel PMDs */
132 movl %eax,pa(initial_pg_pmd+0x1000*KPMDS-8)
133#else
134 movl %eax,pa(initial_page_table+0xffc)
135#endif
136
137 jmp .Ldefault_entry
138SYM_CODE_END(startup_32)
139
140#ifdef CONFIG_HOTPLUG_CPU
141/*
142 * Boot CPU0 entry point. It's called from play_dead(). Everything has been set
143 * up already except stack. We just set up stack here. Then call
144 * start_secondary().
145 */
146SYM_FUNC_START(start_cpu0)
147 movl initial_stack, %ecx
148 movl %ecx, %esp
149 call *(initial_code)
1501: jmp 1b
151SYM_FUNC_END(start_cpu0)
152#endif
153
154/*
155 * Non-boot CPU entry point; entered from trampoline.S
156 * We can't lgdt here, because lgdt itself uses a data segment, but
157 * we know the trampoline has already loaded the boot_gdt for us.
158 *
159 * If cpu hotplug is not supported then this code can go in init section
160 * which will be freed later
161 */
162SYM_FUNC_START(startup_32_smp)
163 cld
164 movl $(__BOOT_DS),%eax
165 movl %eax,%ds
166 movl %eax,%es
167 movl %eax,%fs
168 movl %eax,%gs
169 movl pa(initial_stack),%ecx
170 movl %eax,%ss
171 leal -__PAGE_OFFSET(%ecx),%esp
172
173#ifdef CONFIG_MICROCODE
174 /* Early load ucode on AP. */
175 call load_ucode_ap
176#endif
177
178.Ldefault_entry:
179 movl $(CR0_STATE & ~X86_CR0_PG),%eax
180 movl %eax,%cr0
181
182/*
183 * We want to start out with EFLAGS unambiguously cleared. Some BIOSes leave
184 * bits like NT set. This would confuse the debugger if this code is traced. So
185 * initialize them properly now before switching to protected mode. That means
186 * DF in particular (even though we have cleared it earlier after copying the
187 * command line) because GCC expects it.
188 */
189 pushl $0
190 popfl
191
192/*
193 * New page tables may be in 4Mbyte page mode and may be using the global pages.
194 *
195 * NOTE! If we are on a 486 we may have no cr4 at all! Specifically, cr4 exists
196 * if and only if CPUID exists and has flags other than the FPU flag set.
197 */
198 movl $-1,pa(X86_CPUID) # preset CPUID level
199 movl $X86_EFLAGS_ID,%ecx
200 pushl %ecx
201 popfl # set EFLAGS=ID
202 pushfl
203 popl %eax # get EFLAGS
204 testl $X86_EFLAGS_ID,%eax # did EFLAGS.ID remained set?
205 jz .Lenable_paging # hw disallowed setting of ID bit
206 # which means no CPUID and no CR4
207
208 xorl %eax,%eax
209 cpuid
210 movl %eax,pa(X86_CPUID) # save largest std CPUID function
211
212 movl $1,%eax
213 cpuid
214 andl $~1,%edx # Ignore CPUID.FPU
215 jz .Lenable_paging # No flags or only CPUID.FPU = no CR4
216
217 movl pa(mmu_cr4_features),%eax
218 movl %eax,%cr4
219
220 testb $X86_CR4_PAE, %al # check if PAE is enabled
221 jz .Lenable_paging
222
223 /* Check if extended functions are implemented */
224 movl $0x80000000, %eax
225 cpuid
226 /* Value must be in the range 0x80000001 to 0x8000ffff */
227 subl $0x80000001, %eax
228 cmpl $(0x8000ffff-0x80000001), %eax
229 ja .Lenable_paging
230
231 /* Clear bogus XD_DISABLE bits */
232 call verify_cpu
233
234 mov $0x80000001, %eax
235 cpuid
236 /* Execute Disable bit supported? */
237 btl $(X86_FEATURE_NX & 31), %edx
238 jnc .Lenable_paging
239
240 /* Setup EFER (Extended Feature Enable Register) */
241 movl $MSR_EFER, %ecx
242 rdmsr
243
244 btsl $_EFER_NX, %eax
245 /* Make changes effective */
246 wrmsr
247
248.Lenable_paging:
249
250/*
251 * Enable paging
252 */
253 movl $pa(initial_page_table), %eax
254 movl %eax,%cr3 /* set the page table pointer.. */
255 movl $CR0_STATE,%eax
256 movl %eax,%cr0 /* ..and set paging (PG) bit */
257 ljmp $__BOOT_CS,$1f /* Clear prefetch and normalize %eip */
2581:
259 /* Shift the stack pointer to a virtual address */
260 addl $__PAGE_OFFSET, %esp
261
262/*
263 * start system 32-bit setup. We need to re-do some of the things done
264 * in 16-bit mode for the "real" operations.
265 */
266 movl setup_once_ref,%eax
267 andl %eax,%eax
268 jz 1f # Did we do this already?
269 call *%eax
2701:
271
272/*
273 * Check if it is 486
274 */
275 movb $4,X86 # at least 486
276 cmpl $-1,X86_CPUID
277 je .Lis486
278
279 /* get vendor info */
280 xorl %eax,%eax # call CPUID with 0 -> return vendor ID
281 cpuid
282 movl %eax,X86_CPUID # save CPUID level
283 movl %ebx,X86_VENDOR_ID # lo 4 chars
284 movl %edx,X86_VENDOR_ID+4 # next 4 chars
285 movl %ecx,X86_VENDOR_ID+8 # last 4 chars
286
287 orl %eax,%eax # do we have processor info as well?
288 je .Lis486
289
290 movl $1,%eax # Use the CPUID instruction to get CPU type
291 cpuid
292 movb %al,%cl # save reg for future use
293 andb $0x0f,%ah # mask processor family
294 movb %ah,X86
295 andb $0xf0,%al # mask model
296 shrb $4,%al
297 movb %al,X86_MODEL
298 andb $0x0f,%cl # mask mask revision
299 movb %cl,X86_STEPPING
300 movl %edx,X86_CAPABILITY
301
302.Lis486:
303 movl $0x50022,%ecx # set AM, WP, NE and MP
304 movl %cr0,%eax
305 andl $0x80000011,%eax # Save PG,PE,ET
306 orl %ecx,%eax
307 movl %eax,%cr0
308
309 lgdt early_gdt_descr
310 ljmp $(__KERNEL_CS),$1f
3111: movl $(__KERNEL_DS),%eax # reload all the segment registers
312 movl %eax,%ss # after changing gdt.
313
314 movl $(__USER_DS),%eax # DS/ES contains default USER segment
315 movl %eax,%ds
316 movl %eax,%es
317
318 movl $(__KERNEL_PERCPU), %eax
319 movl %eax,%fs # set this cpu's percpu
320
321 movl $(__KERNEL_STACK_CANARY),%eax
322 movl %eax,%gs
323
324 xorl %eax,%eax # Clear LDT
325 lldt %ax
326
327 call *(initial_code)
3281: jmp 1b
329SYM_FUNC_END(startup_32_smp)
330
331#include "verify_cpu.S"
332
333/*
334 * setup_once
335 *
336 * The setup work we only want to run on the BSP.
337 *
338 * Warning: %esi is live across this function.
339 */
340__INIT
341setup_once:
342#ifdef CONFIG_STACKPROTECTOR
343 /*
344 * Configure the stack canary. The linker can't handle this by
345 * relocation. Manually set base address in stack canary
346 * segment descriptor.
347 */
348 movl $gdt_page,%eax
349 movl $stack_canary,%ecx
350 movw %cx, 8 * GDT_ENTRY_STACK_CANARY + 2(%eax)
351 shrl $16, %ecx
352 movb %cl, 8 * GDT_ENTRY_STACK_CANARY + 4(%eax)
353 movb %ch, 8 * GDT_ENTRY_STACK_CANARY + 7(%eax)
354#endif
355
356 andl $0,setup_once_ref /* Once is enough, thanks */
357 ret
358
359SYM_FUNC_START(early_idt_handler_array)
360 # 36(%esp) %eflags
361 # 32(%esp) %cs
362 # 28(%esp) %eip
363 # 24(%rsp) error code
364 i = 0
365 .rept NUM_EXCEPTION_VECTORS
366 .if ((EXCEPTION_ERRCODE_MASK >> i) & 1) == 0
367 pushl $0 # Dummy error code, to make stack frame uniform
368 .endif
369 pushl $i # 20(%esp) Vector number
370 jmp early_idt_handler_common
371 i = i + 1
372 .fill early_idt_handler_array + i*EARLY_IDT_HANDLER_SIZE - ., 1, 0xcc
373 .endr
374SYM_FUNC_END(early_idt_handler_array)
375
376SYM_CODE_START_LOCAL(early_idt_handler_common)
377 /*
378 * The stack is the hardware frame, an error code or zero, and the
379 * vector number.
380 */
381 cld
382
383 incl %ss:early_recursion_flag
384
385 /* The vector number is in pt_regs->gs */
386
387 cld
388 pushl %fs /* pt_regs->fs (__fsh varies by model) */
389 pushl %es /* pt_regs->es (__esh varies by model) */
390 pushl %ds /* pt_regs->ds (__dsh varies by model) */
391 pushl %eax /* pt_regs->ax */
392 pushl %ebp /* pt_regs->bp */
393 pushl %edi /* pt_regs->di */
394 pushl %esi /* pt_regs->si */
395 pushl %edx /* pt_regs->dx */
396 pushl %ecx /* pt_regs->cx */
397 pushl %ebx /* pt_regs->bx */
398
399 /* Fix up DS and ES */
400 movl $(__KERNEL_DS), %ecx
401 movl %ecx, %ds
402 movl %ecx, %es
403
404 /* Load the vector number into EDX */
405 movl PT_GS(%esp), %edx
406
407 /* Load GS into pt_regs->gs (and maybe clobber __gsh) */
408 movw %gs, PT_GS(%esp)
409
410 movl %esp, %eax /* args are pt_regs (EAX), trapnr (EDX) */
411 call early_fixup_exception
412
413 popl %ebx /* pt_regs->bx */
414 popl %ecx /* pt_regs->cx */
415 popl %edx /* pt_regs->dx */
416 popl %esi /* pt_regs->si */
417 popl %edi /* pt_regs->di */
418 popl %ebp /* pt_regs->bp */
419 popl %eax /* pt_regs->ax */
420 popl %ds /* pt_regs->ds (always ignores __dsh) */
421 popl %es /* pt_regs->es (always ignores __esh) */
422 popl %fs /* pt_regs->fs (always ignores __fsh) */
423 popl %gs /* pt_regs->gs (always ignores __gsh) */
424 decl %ss:early_recursion_flag
425 addl $4, %esp /* pop pt_regs->orig_ax */
426 iret
427SYM_CODE_END(early_idt_handler_common)
428
429/* This is the default interrupt "handler" :-) */
430SYM_FUNC_START(early_ignore_irq)
431 cld
432#ifdef CONFIG_PRINTK
433 pushl %eax
434 pushl %ecx
435 pushl %edx
436 pushl %es
437 pushl %ds
438 movl $(__KERNEL_DS),%eax
439 movl %eax,%ds
440 movl %eax,%es
441 cmpl $2,early_recursion_flag
442 je hlt_loop
443 incl early_recursion_flag
444 pushl 16(%esp)
445 pushl 24(%esp)
446 pushl 32(%esp)
447 pushl 40(%esp)
448 pushl $int_msg
449 call printk
450
451 call dump_stack
452
453 addl $(5*4),%esp
454 popl %ds
455 popl %es
456 popl %edx
457 popl %ecx
458 popl %eax
459#endif
460 iret
461
462hlt_loop:
463 hlt
464 jmp hlt_loop
465SYM_FUNC_END(early_ignore_irq)
466
467__INITDATA
468 .align 4
469SYM_DATA(early_recursion_flag, .long 0)
470
471__REFDATA
472 .align 4
473SYM_DATA(initial_code, .long i386_start_kernel)
474SYM_DATA(setup_once_ref, .long setup_once)
475
476#ifdef CONFIG_PAGE_TABLE_ISOLATION
477#define PGD_ALIGN (2 * PAGE_SIZE)
478#define PTI_USER_PGD_FILL 1024
479#else
480#define PGD_ALIGN (PAGE_SIZE)
481#define PTI_USER_PGD_FILL 0
482#endif
483/*
484 * BSS section
485 */
486__PAGE_ALIGNED_BSS
487 .align PGD_ALIGN
488#ifdef CONFIG_X86_PAE
489.globl initial_pg_pmd
490initial_pg_pmd:
491 .fill 1024*KPMDS,4,0
492#else
493.globl initial_page_table
494initial_page_table:
495 .fill 1024,4,0
496#endif
497 .align PGD_ALIGN
498initial_pg_fixmap:
499 .fill 1024,4,0
500.globl swapper_pg_dir
501 .align PGD_ALIGN
502swapper_pg_dir:
503 .fill 1024,4,0
504 .fill PTI_USER_PGD_FILL,4,0
505.globl empty_zero_page
506empty_zero_page:
507 .fill 4096,1,0
508EXPORT_SYMBOL(empty_zero_page)
509
510/*
511 * This starts the data section.
512 */
513#ifdef CONFIG_X86_PAE
514__PAGE_ALIGNED_DATA
515 /* Page-aligned for the benefit of paravirt? */
516 .align PGD_ALIGN
517SYM_DATA_START(initial_page_table)
518 .long pa(initial_pg_pmd+PGD_IDENT_ATTR),0 /* low identity map */
519# if KPMDS == 3
520 .long pa(initial_pg_pmd+PGD_IDENT_ATTR),0
521 .long pa(initial_pg_pmd+PGD_IDENT_ATTR+0x1000),0
522 .long pa(initial_pg_pmd+PGD_IDENT_ATTR+0x2000),0
523# elif KPMDS == 2
524 .long 0,0
525 .long pa(initial_pg_pmd+PGD_IDENT_ATTR),0
526 .long pa(initial_pg_pmd+PGD_IDENT_ATTR+0x1000),0
527# elif KPMDS == 1
528 .long 0,0
529 .long 0,0
530 .long pa(initial_pg_pmd+PGD_IDENT_ATTR),0
531# else
532# error "Kernel PMDs should be 1, 2 or 3"
533# endif
534 .align PAGE_SIZE /* needs to be page-sized too */
535
536#ifdef CONFIG_PAGE_TABLE_ISOLATION
537 /*
538 * PTI needs another page so sync_initial_pagetable() works correctly
539 * and does not scribble over the data which is placed behind the
540 * actual initial_page_table. See clone_pgd_range().
541 */
542 .fill 1024, 4, 0
543#endif
544
545SYM_DATA_END(initial_page_table)
546#endif
547
548.data
549.balign 4
550/*
551 * The SIZEOF_PTREGS gap is a convention which helps the in-kernel unwinder
552 * reliably detect the end of the stack.
553 */
554SYM_DATA(initial_stack,
555 .long init_thread_union + THREAD_SIZE -
556 SIZEOF_PTREGS - TOP_OF_KERNEL_STACK_PADDING)
557
558__INITRODATA
559int_msg:
560 .asciz "Unknown interrupt or fault at: %p %p %p\n"
561
562#include "../../x86/xen/xen-head.S"
563
564/*
565 * The IDT and GDT 'descriptors' are a strange 48-bit object
566 * only used by the lidt and lgdt instructions. They are not
567 * like usual segment descriptors - they consist of a 16-bit
568 * segment size, and 32-bit linear address value:
569 */
570
571 .data
572 ALIGN
573# early boot GDT descriptor (must use 1:1 address mapping)
574 .word 0 # 32 bit align gdt_desc.address
575SYM_DATA_START_LOCAL(boot_gdt_descr)
576 .word __BOOT_DS+7
577 .long boot_gdt - __PAGE_OFFSET
578SYM_DATA_END(boot_gdt_descr)
579
580# boot GDT descriptor (later on used by CPU#0):
581 .word 0 # 32 bit align gdt_desc.address
582SYM_DATA_START(early_gdt_descr)
583 .word GDT_ENTRIES*8-1
584 .long gdt_page /* Overwritten for secondary CPUs */
585SYM_DATA_END(early_gdt_descr)
586
587/*
588 * The boot_gdt must mirror the equivalent in setup.S and is
589 * used only for booting.
590 */
591 .align L1_CACHE_BYTES
592SYM_DATA_START(boot_gdt)
593 .fill GDT_ENTRY_BOOT_CS,8,0
594 .quad 0x00cf9a000000ffff /* kernel 4GB code at 0x00000000 */
595 .quad 0x00cf92000000ffff /* kernel 4GB data at 0x00000000 */
596SYM_DATA_END(boot_gdt)