1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 *
6 * Enhanced CPU detection and feature setting
7 * and Martin Mares, November 1997.
8 */
9
10 .text
11 #include <linux/export.h>
12 #include <linux/threads.h>
13 #include <linux/init.h>
14 #include <linux/linkage.h>
15 #include <asm/segment.h>
16 #include <asm/page_types.h>
17 #include <asm/pgtable_types.h>
18 #include <asm/cache.h>
19 #include <asm/thread_info.h>
20 #include <asm/asm-offsets.h>
21 #include <asm/setup.h>
22 #include <asm/processor-flags.h>
23 #include <asm/msr-index.h>
24 #include <asm/cpufeatures.h>
25 #include <asm/percpu.h>
26 #include <asm/nops.h>
27 #include <asm/nospec-branch.h>
28 #include <asm/bootparam.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 s
36 */
37
38 #define X86 new_cpu_data+CPUINFO_x
39 #define X86_VENDOR new_cpu_data+CPUINFO_x
40 #define X86_MODEL new_cpu_data+CPUINFO_x
41 #define X86_STEPPING new_cpu_data+CPUINFO_x
42 #define X86_HARD_MATH new_cpu_data+CPUINFO_h
43 #define X86_CPUID new_cpu_data+CPUINFO_c
44 #define X86_CAPABILITY new_cpu_data+CPUINFO_x
45 #define X86_VENDOR_ID new_cpu_data+CPUINFO_x
46
47 /*
48 * Worst-case size of the kernel mapping we ne
49 * a relocatable kernel can live anywhere in l
50 * to map all of lowmem.
51 */
52 KERNEL_PAGES = LOWMEM_PAGES
53
54 INIT_MAP_SIZE = PAGE_TABLE_SIZE(KERNEL_PAGES)
55 RESERVE_BRK(pagetables, INIT_MAP_SIZE)
56
57 /*
58 * 32-bit kernel entrypoint; only used by the
59 * %esi points to the real-mode code as a 32-b
60 * CS and DS must be 4 GB flat segments, but w
61 * any particular GDT layout, because we load
62 * can.
63 */
64 __HEAD
65 SYM_CODE_START(startup_32)
66 movl pa(initial_stack),%ecx
67
68 /*
69 * Set segments to known values.
70 */
71 lgdt pa(boot_gdt_descr)
72 movl $(__BOOT_DS),%eax
73 movl %eax,%ds
74 movl %eax,%es
75 movl %eax,%fs
76 movl %eax,%gs
77 movl %eax,%ss
78 leal -__PAGE_OFFSET(%ecx),%esp
79
80 /*
81 * Clear BSS first so that there are no surpri
82 */
83 cld
84 xorl %eax,%eax
85 movl $pa(__bss_start),%edi
86 movl $pa(__bss_stop),%ecx
87 subl %edi,%ecx
88 shrl $2,%ecx
89 rep ; stosl
90 /*
91 * Copy bootup parameters out of the way.
92 * Note: %esi still has the pointer to the rea
93 * With the kexec as boot loader, parameter se
94 * kernel image and might not even be addressa
95 * (kexec on panic case). Hence copy out the p
96 * page tables.
97 */
98 movl $pa(boot_params),%edi
99 movl $(PARAM_SIZE/4),%ecx
100 cld
101 rep
102 movsl
103 movl pa(boot_params) + NEW_CL_POINTER,
104 andl %esi,%esi
105 jz 1f # No command l
106 movl $pa(boot_command_line),%edi
107 movl $(COMMAND_LINE_SIZE/4),%ecx
108 rep
109 movsl
110 1:
111
112 #ifdef CONFIG_OLPC
113 /* save OFW's pgdir table for later us
114 movl %cr3, %eax
115 movl %eax, pa(olpc_ofw_pgd)
116 #endif
117
118 /* Create early pagetables. */
119 call mk_early_pgtbl_32
120
121 /* Do early initialization of the fixm
122 movl $pa(initial_pg_fixmap)+PDE_IDENT_
123 #ifdef CONFIG_X86_PAE
124 #define KPMDS (((-__PAGE_OFFSET) >> 30) & 3) /
125 movl %eax,pa(initial_pg_pmd+0x1000*KPM
126 #else
127 movl %eax,pa(initial_page_table+0xffc)
128 #endif
129
130 jmp .Ldefault_entry
131 SYM_CODE_END(startup_32)
132
133 /*
134 * Non-boot CPU entry point; entered from tram
135 * We can't lgdt here, because lgdt itself use
136 * we know the trampoline has already loaded t
137 *
138 * If cpu hotplug is not supported then this c
139 * which will be freed later
140 */
141 SYM_FUNC_START(startup_32_smp)
142 cld
143 movl $(__BOOT_DS),%eax
144 movl %eax,%ds
145 movl %eax,%es
146 movl %eax,%fs
147 movl %eax,%gs
148 movl pa(initial_stack),%ecx
149 movl %eax,%ss
150 leal -__PAGE_OFFSET(%ecx),%esp
151
152 .Ldefault_entry:
153 movl $(CR0_STATE & ~X86_CR0_PG),%eax
154 movl %eax,%cr0
155
156 /*
157 * We want to start out with EFLAGS unambiguou
158 * bits like NT set. This would confuse the de
159 * initialize them properly now before switchi
160 * DF in particular (even though we have clear
161 * command line) because GCC expects it.
162 */
163 pushl $0
164 popfl
165
166 /*
167 * New page tables may be in 4Mbyte page mode
168 *
169 * NOTE! If we are on a 486 we may have no cr4
170 * if and only if CPUID exists and has flags o
171 */
172 movl $-1,pa(X86_CPUID) # pres
173 movl $X86_EFLAGS_ID,%ecx
174 pushl %ecx
175 popfl # set
176 pushfl
177 popl %eax # get
178 testl $X86_EFLAGS_ID,%eax # did
179 jz .Lenable_paging # hw d
180 # whic
181
182 xorl %eax,%eax
183 cpuid
184 movl %eax,pa(X86_CPUID) # save
185
186 movl $1,%eax
187 cpuid
188 andl $~1,%edx # Igno
189 jz .Lenable_paging # No f
190
191 movl pa(mmu_cr4_features),%eax
192 movl %eax,%cr4
193
194 testb $X86_CR4_PAE, %al # chec
195 jz .Lenable_paging
196
197 /* Check if extended functions are imp
198 movl $0x80000000, %eax
199 cpuid
200 /* Value must be in the range 0x800000
201 subl $0x80000001, %eax
202 cmpl $(0x8000ffff-0x80000001), %eax
203 ja .Lenable_paging
204
205 /* Clear bogus XD_DISABLE bits */
206 call verify_cpu
207
208 mov $0x80000001, %eax
209 cpuid
210 /* Execute Disable bit supported? */
211 btl $(X86_FEATURE_NX & 31), %edx
212 jnc .Lenable_paging
213
214 /* Setup EFER (Extended Feature Enable
215 movl $MSR_EFER, %ecx
216 rdmsr
217
218 btsl $_EFER_NX, %eax
219 /* Make changes effective */
220 wrmsr
221
222 .Lenable_paging:
223
224 /*
225 * Enable paging
226 */
227 movl $pa(initial_page_table), %eax
228 movl %eax,%cr3 /* set the pag
229 movl $CR0_STATE,%eax
230 movl %eax,%cr0 /* ..and set p
231 ljmp $__BOOT_CS,$1f /* Clear prefe
232 1:
233 /* Shift the stack pointer to a virtua
234 addl $__PAGE_OFFSET, %esp
235
236 /*
237 * Check if it is 486
238 */
239 movb $4,X86 # at l
240 cmpl $-1,X86_CPUID
241 je .Lis486
242
243 /* get vendor info */
244 xorl %eax,%eax # call
245 cpuid
246 movl %eax,X86_CPUID # save
247 movl %ebx,X86_VENDOR_ID # lo 4
248 movl %edx,X86_VENDOR_ID+4 # next
249 movl %ecx,X86_VENDOR_ID+8 # last
250
251 orl %eax,%eax # do w
252 je .Lis486
253
254 movl $1,%eax # Use the CPUI
255 cpuid
256 movb %al,%cl # save reg for
257 andb $0x0f,%ah # mask process
258 movb %ah,X86
259 andb $0xf0,%al # mask model
260 shrb $4,%al
261 movb %al,X86_MODEL
262 andb $0x0f,%cl # mask mask re
263 movb %cl,X86_STEPPING
264 movl %edx,X86_CAPABILITY
265
266 .Lis486:
267 movl $0x50022,%ecx # set AM, WP,
268 movl %cr0,%eax
269 andl $0x80000011,%eax # Save PG,PE,E
270 orl %ecx,%eax
271 movl %eax,%cr0
272
273 lgdt early_gdt_descr
274 ljmp $(__KERNEL_CS),$1f
275 1: movl $(__KERNEL_DS),%eax # relo
276 movl %eax,%ss # afte
277
278 movl $(__USER_DS),%eax # DS/E
279 movl %eax,%ds
280 movl %eax,%es
281
282 movl $(__KERNEL_PERCPU), %eax
283 movl %eax,%fs # set
284
285 xorl %eax,%eax
286 movl %eax,%gs # clea
287
288 xorl %eax,%eax # Clea
289 lldt %ax
290
291 call *(initial_code)
292 1: jmp 1b
293 SYM_FUNC_END(startup_32_smp)
294
295 #include "verify_cpu.S"
296
297 __INIT
298 SYM_FUNC_START(early_idt_handler_array)
299 # 36(%esp) %eflags
300 # 32(%esp) %cs
301 # 28(%esp) %eip
302 # 24(%rsp) error code
303 i = 0
304 .rept NUM_EXCEPTION_VECTORS
305 .if ((EXCEPTION_ERRCODE_MASK >> i) & 1
306 pushl $0 # Dummy error
307 .endif
308 pushl $i # 20(%esp) Vec
309 jmp early_idt_handler_common
310 i = i + 1
311 .fill early_idt_handler_array + i*EARL
312 .endr
313 SYM_FUNC_END(early_idt_handler_array)
314
315 SYM_CODE_START_LOCAL(early_idt_handler_common)
316 /*
317 * The stack is the hardware frame, an
318 * vector number.
319 */
320 cld
321
322 incl %ss:early_recursion_flag
323
324 /* The vector number is in pt_regs->gs
325
326 cld
327 pushl %fs /* pt_regs->fs
328 pushl %es /* pt_regs->es
329 pushl %ds /* pt_regs->ds
330 pushl %eax /* pt_regs->ax
331 pushl %ebp /* pt_regs->bp
332 pushl %edi /* pt_regs->di
333 pushl %esi /* pt_regs->si
334 pushl %edx /* pt_regs->dx
335 pushl %ecx /* pt_regs->cx
336 pushl %ebx /* pt_regs->bx
337
338 /* Fix up DS and ES */
339 movl $(__KERNEL_DS), %ecx
340 movl %ecx, %ds
341 movl %ecx, %es
342
343 /* Load the vector number into EDX */
344 movl PT_GS(%esp), %edx
345
346 /* Load GS into pt_regs->gs (and maybe
347 movw %gs, PT_GS(%esp)
348
349 movl %esp, %eax /* args are pt
350 call early_fixup_exception
351
352 popl %ebx /* pt_regs->bx
353 popl %ecx /* pt_regs->cx
354 popl %edx /* pt_regs->dx
355 popl %esi /* pt_regs->si
356 popl %edi /* pt_regs->di
357 popl %ebp /* pt_regs->bp
358 popl %eax /* pt_regs->ax
359 popl %ds /* pt_regs->ds
360 popl %es /* pt_regs->es
361 popl %fs /* pt_regs->fs
362 popl %gs /* pt_regs->gs
363 decl %ss:early_recursion_flag
364 addl $4, %esp /* pop pt_regs
365 iret
366 SYM_CODE_END(early_idt_handler_common)
367
368 /* This is the default interrupt "handler" :-)
369 SYM_FUNC_START(early_ignore_irq)
370 cld
371 #ifdef CONFIG_PRINTK
372 pushl %eax
373 pushl %ecx
374 pushl %edx
375 pushl %es
376 pushl %ds
377 movl $(__KERNEL_DS),%eax
378 movl %eax,%ds
379 movl %eax,%es
380 cmpl $2,early_recursion_flag
381 je hlt_loop
382 incl early_recursion_flag
383 pushl 16(%esp)
384 pushl 24(%esp)
385 pushl 32(%esp)
386 pushl 40(%esp)
387 pushl $int_msg
388 call _printk
389
390 call dump_stack
391
392 addl $(5*4),%esp
393 popl %ds
394 popl %es
395 popl %edx
396 popl %ecx
397 popl %eax
398 #endif
399 iret
400
401 hlt_loop:
402 hlt
403 jmp hlt_loop
404 SYM_FUNC_END(early_ignore_irq)
405
406 __INITDATA
407 .align 4
408 SYM_DATA(early_recursion_flag, .long 0)
409
410 __REFDATA
411 .align 4
412 SYM_DATA(initial_code, .long i386_sta
413
414 #ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION
415 #define PGD_ALIGN (2 * PAGE_SIZE)
416 #define PTI_USER_PGD_FILL 1024
417 #else
418 #define PGD_ALIGN (PAGE_SIZE)
419 #define PTI_USER_PGD_FILL 0
420 #endif
421 /*
422 * BSS section
423 */
424 __PAGE_ALIGNED_BSS
425 .align PGD_ALIGN
426 #ifdef CONFIG_X86_PAE
427 .globl initial_pg_pmd
428 initial_pg_pmd:
429 .fill 1024*KPMDS,4,0
430 #else
431 .globl initial_page_table
432 initial_page_table:
433 .fill 1024,4,0
434 #endif
435 .align PGD_ALIGN
436 initial_pg_fixmap:
437 .fill 1024,4,0
438 .globl swapper_pg_dir
439 .align PGD_ALIGN
440 swapper_pg_dir:
441 .fill 1024,4,0
442 .fill PTI_USER_PGD_FILL,4,0
443 .globl empty_zero_page
444 empty_zero_page:
445 .fill 4096,1,0
446 EXPORT_SYMBOL(empty_zero_page)
447
448 /*
449 * This starts the data section.
450 */
451 #ifdef CONFIG_X86_PAE
452 __PAGE_ALIGNED_DATA
453 /* Page-aligned for the benefit of par
454 .align PGD_ALIGN
455 SYM_DATA_START(initial_page_table)
456 .long pa(initial_pg_pmd+PGD_IDENT_AT
457 # if KPMDS == 3
458 .long pa(initial_pg_pmd+PGD_IDENT_AT
459 .long pa(initial_pg_pmd+PGD_IDENT_AT
460 .long pa(initial_pg_pmd+PGD_IDENT_AT
461 # elif KPMDS == 2
462 .long 0,0
463 .long pa(initial_pg_pmd+PGD_IDENT_AT
464 .long pa(initial_pg_pmd+PGD_IDENT_AT
465 # elif KPMDS == 1
466 .long 0,0
467 .long 0,0
468 .long pa(initial_pg_pmd+PGD_IDENT_AT
469 # else
470 # error "Kernel PMDs should be 1, 2 or 3"
471 # endif
472 .align PAGE_SIZE /* nee
473
474 #ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION
475 /*
476 * PTI needs another page so sync_init
477 * and does not scribble over the data
478 * actual initial_page_table. See clon
479 */
480 .fill 1024, 4, 0
481 #endif
482
483 SYM_DATA_END(initial_page_table)
484 #endif
485
486 .data
487 .balign 4
488 SYM_DATA(initial_stack, .long __top_init_kerne
489
490 __INITRODATA
491 int_msg:
492 .asciz "Unknown interrupt or fault at:
493
494 #include "../xen/xen-head.S"
495
496 /*
497 * The IDT and GDT 'descriptors' are a strange
498 * only used by the lidt and lgdt instructions
499 * like usual segment descriptors - they consi
500 * segment size, and 32-bit linear address val
501 */
502
503 .data
504 ALIGN
505 # early boot GDT descriptor (must use 1:1 addr
506 .word 0 # 32 b
507 SYM_DATA_START_LOCAL(boot_gdt_descr)
508 .word __BOOT_DS+7
509 .long boot_gdt - __PAGE_OFFSET
510 SYM_DATA_END(boot_gdt_descr)
511
512 # boot GDT descriptor (later on used by CPU#0)
513 .word 0 # 32 b
514 SYM_DATA_START(early_gdt_descr)
515 .word GDT_ENTRIES*8-1
516 .long gdt_page /* Ove
517 SYM_DATA_END(early_gdt_descr)
518
519 /*
520 * The boot_gdt must mirror the equivalent in
521 * used only for booting.
522 */
523 .align L1_CACHE_BYTES
524 SYM_DATA_START(boot_gdt)
525 .fill GDT_ENTRY_BOOT_CS,8,0
526 .quad 0x00cf9a000000ffff /* ker
527 .quad 0x00cf92000000ffff /* ker
528 SYM_DATA_END(boot_gdt)
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