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Merge branch 'bkl/procfs' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic...
[linux-2.6-block.git] / arch / x86 / kernel / entry_32.S
CommitLineData
1da177e4 1/*
1da177e4
LT		 2 *
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 */
5
6/*
7 * entry.S contains the system-call and fault low-level handling routines.
8 * This also contains the timer-interrupt handler, as well as all interrupts
9 * and faults that can result in a task-switch.
10 *
11 * NOTE: This code handles signal-recognition, which happens every time
12 * after a timer-interrupt and after each system call.
13 *
14 * I changed all the .align's to 4 (16 byte alignment), as that's faster
15 * on a 486.
16 *
889f21ce 17 * Stack layout in 'syscall_exit':
1da177e4
LT		 18 * ptrace needs to have all regs on the stack.
19 * if the order here is changed, it needs to be
20 * updated in fork.c:copy_process, signal.c:do_signal,
21 * ptrace.c and ptrace.h
22 *
23 * 0(%esp) - %ebx
24 * 4(%esp) - %ecx
25 * 8(%esp) - %edx
26 * C(%esp) - %esi
27 * 10(%esp) - %edi
28 * 14(%esp) - %ebp
29 * 18(%esp) - %eax
30 * 1C(%esp) - %ds
31 * 20(%esp) - %es
464d1a78 32 * 24(%esp) - %fs
ccbeed3a
TH		 33 * 28(%esp) - %gs saved iff !CONFIG_X86_32_LAZY_GS
34 * 2C(%esp) - orig_eax
35 * 30(%esp) - %eip
36 * 34(%esp) - %cs
37 * 38(%esp) - %eflags
38 * 3C(%esp) - %oldesp
39 * 40(%esp) - %oldss
1da177e4
LT		 40 *
41 * "current" is in register %ebx during any slow entries.
42 */
43
1da177e4
LT		 44#include <linux/linkage.h>
45#include <asm/thread_info.h>
55f327fa 46#include <asm/irqflags.h>
1da177e4
LT		 47#include <asm/errno.h>
48#include <asm/segment.h>
49#include <asm/smp.h>
0341c14d 50#include <asm/page_types.h>
be44d2aa 51#include <asm/percpu.h>
fe7cacc1 52#include <asm/dwarf2.h>
ab68ed98 53#include <asm/processor-flags.h>
395a59d0 54#include <asm/ftrace.h>
9b7dc567 55#include <asm/irq_vectors.h>
40d2e763 56#include <asm/cpufeature.h>
1da177e4 57
af0575bb
RM		 58/* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */
59#include <linux/elf-em.h>
60#define AUDIT_ARCH_I386 (EM_386|__AUDIT_ARCH_LE)
61#define __AUDIT_ARCH_LE 0x40000000
62
63#ifndef CONFIG_AUDITSYSCALL
64#define sysenter_audit syscall_trace_entry
65#define sysexit_audit syscall_exit_work
66#endif
67
139ec7c4
RR		 68/*
69 * We use macros for low-level operations which need to be overridden
70 * for paravirtualization. The following will never clobber any registers:
71 * INTERRUPT_RETURN (aka. "iret")
72 * GET_CR0_INTO_EAX (aka. "movl %cr0, %eax")
d75cd22f 73 * ENABLE_INTERRUPTS_SYSEXIT (aka "sti; sysexit").
139ec7c4
RR		 74 *
75 * For DISABLE_INTERRUPTS/ENABLE_INTERRUPTS (aka "cli"/"sti"), you must
76 * specify what registers can be overwritten (CLBR_NONE, CLBR_EAX/EDX/ECX/ANY).
77 * Allowing a register to be clobbered can shrink the paravirt replacement
78 * enough to patch inline, increasing performance.
79 */
80
1da177e4
LT		 81#define nr_syscalls ((syscall_table_size)/4)
82
1da177e4 83#ifdef CONFIG_PREEMPT
139ec7c4 84#define preempt_stop(clobbers) DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF
1da177e4 85#else
139ec7c4 86#define preempt_stop(clobbers)
2e04bc76 87#define resume_kernel restore_all
1da177e4
LT		 88#endif
89
55f327fa
IM		 90.macro TRACE_IRQS_IRET
91#ifdef CONFIG_TRACE_IRQFLAGS
ab68ed98 92 testl $X86_EFLAGS_IF,PT_EFLAGS(%esp) # interrupts off?
55f327fa
IM		 93 jz 1f
94 TRACE_IRQS_ON
951:
96#endif
97.endm
98
4031ff38
AG		 99#ifdef CONFIG_VM86
100#define resume_userspace_sig check_userspace
101#else
102#define resume_userspace_sig resume_userspace
103#endif
104
ccbeed3a
TH		 105/*
106 * User gs save/restore
107 *
108 * %gs is used for userland TLS and kernel only uses it for stack
109 * canary which is required to be at %gs:20 by gcc. Read the comment
110 * at the top of stackprotector.h for more info.
111 *
112 * Local labels 98 and 99 are used.
113 */
114#ifdef CONFIG_X86_32_LAZY_GS
115
116 /* unfortunately push/pop can't be no-op */
117.macro PUSH_GS
118 pushl $0
119 CFI_ADJUST_CFA_OFFSET 4
120.endm
121.macro POP_GS pop=0
122 addl $(4 + \pop), %esp
123 CFI_ADJUST_CFA_OFFSET -(4 + \pop)
124.endm
125.macro POP_GS_EX
126.endm
127
128 /* all the rest are no-op */
129.macro PTGS_TO_GS
130.endm
131.macro PTGS_TO_GS_EX
132.endm
133.macro GS_TO_REG reg
134.endm
135.macro REG_TO_PTGS reg
136.endm
137.macro SET_KERNEL_GS reg
138.endm
139
140#else /* CONFIG_X86_32_LAZY_GS */
141
142.macro PUSH_GS
143 pushl %gs
144 CFI_ADJUST_CFA_OFFSET 4
145 /*CFI_REL_OFFSET gs, 0*/
146.endm
147
148.macro POP_GS pop=0
14998: popl %gs
150 CFI_ADJUST_CFA_OFFSET -4
151 /*CFI_RESTORE gs*/
152 .if \pop <> 0
153 add $\pop, %esp
154 CFI_ADJUST_CFA_OFFSET -\pop
155 .endif
156.endm
157.macro POP_GS_EX
158.pushsection .fixup, "ax"
15999: movl $0, (%esp)
160 jmp 98b
161.section __ex_table, "a"
162 .align 4
163 .long 98b, 99b
164.popsection
165.endm
166
167.macro PTGS_TO_GS
16898: mov PT_GS(%esp), %gs
169.endm
170.macro PTGS_TO_GS_EX
171.pushsection .fixup, "ax"
17299: movl $0, PT_GS(%esp)
173 jmp 98b
174.section __ex_table, "a"
175 .align 4
176 .long 98b, 99b
177.popsection
178.endm
179
180.macro GS_TO_REG reg
181 movl %gs, \reg
182 /*CFI_REGISTER gs, \reg*/
183.endm
184.macro REG_TO_PTGS reg
185 movl \reg, PT_GS(%esp)
186 /*CFI_REL_OFFSET gs, PT_GS*/
187.endm
188.macro SET_KERNEL_GS reg
60a5317f 189 movl $(__KERNEL_STACK_CANARY), \reg
ccbeed3a
TH		 190 movl \reg, %gs
191.endm
192
193#endif /* CONFIG_X86_32_LAZY_GS */
194
f0d96110
TH		 195.macro SAVE_ALL
196 cld
ccbeed3a 197 PUSH_GS
f0d96110
TH		 198 pushl %fs
199 CFI_ADJUST_CFA_OFFSET 4
200 /*CFI_REL_OFFSET fs, 0;*/
201 pushl %es
202 CFI_ADJUST_CFA_OFFSET 4
203 /*CFI_REL_OFFSET es, 0;*/
204 pushl %ds
205 CFI_ADJUST_CFA_OFFSET 4
206 /*CFI_REL_OFFSET ds, 0;*/
207 pushl %eax
208 CFI_ADJUST_CFA_OFFSET 4
209 CFI_REL_OFFSET eax, 0
210 pushl %ebp
211 CFI_ADJUST_CFA_OFFSET 4
212 CFI_REL_OFFSET ebp, 0
213 pushl %edi
214 CFI_ADJUST_CFA_OFFSET 4
215 CFI_REL_OFFSET edi, 0
216 pushl %esi
217 CFI_ADJUST_CFA_OFFSET 4
218 CFI_REL_OFFSET esi, 0
219 pushl %edx
220 CFI_ADJUST_CFA_OFFSET 4
221 CFI_REL_OFFSET edx, 0
222 pushl %ecx
223 CFI_ADJUST_CFA_OFFSET 4
224 CFI_REL_OFFSET ecx, 0
225 pushl %ebx
226 CFI_ADJUST_CFA_OFFSET 4
227 CFI_REL_OFFSET ebx, 0
228 movl $(__USER_DS), %edx
229 movl %edx, %ds
230 movl %edx, %es
231 movl $(__KERNEL_PERCPU), %edx
464d1a78 232 movl %edx, %fs
ccbeed3a 233 SET_KERNEL_GS %edx
f0d96110 234.endm
1da177e4 235
f0d96110
TH		 236.macro RESTORE_INT_REGS
237 popl %ebx
238 CFI_ADJUST_CFA_OFFSET -4
239 CFI_RESTORE ebx
240 popl %ecx
241 CFI_ADJUST_CFA_OFFSET -4
242 CFI_RESTORE ecx
243 popl %edx
244 CFI_ADJUST_CFA_OFFSET -4
245 CFI_RESTORE edx
246 popl %esi
247 CFI_ADJUST_CFA_OFFSET -4
248 CFI_RESTORE esi
249 popl %edi
250 CFI_ADJUST_CFA_OFFSET -4
251 CFI_RESTORE edi
252 popl %ebp
253 CFI_ADJUST_CFA_OFFSET -4
254 CFI_RESTORE ebp
255 popl %eax
256 CFI_ADJUST_CFA_OFFSET -4
fe7cacc1 257 CFI_RESTORE eax
f0d96110 258.endm
1da177e4 259
ccbeed3a 260.macro RESTORE_REGS pop=0
f0d96110
TH		 261 RESTORE_INT_REGS
2621: popl %ds
263 CFI_ADJUST_CFA_OFFSET -4
264 /*CFI_RESTORE ds;*/
2652: popl %es
266 CFI_ADJUST_CFA_OFFSET -4
267 /*CFI_RESTORE es;*/
2683: popl %fs
269 CFI_ADJUST_CFA_OFFSET -4
270 /*CFI_RESTORE fs;*/
ccbeed3a 271 POP_GS \pop
f0d96110
TH		 272.pushsection .fixup, "ax"
2734: movl $0, (%esp)
274 jmp 1b
2755: movl $0, (%esp)
276 jmp 2b
2776: movl $0, (%esp)
278 jmp 3b
279.section __ex_table, "a"
280 .align 4
281 .long 1b, 4b
282 .long 2b, 5b
283 .long 3b, 6b
f95d47ca 284.popsection
ccbeed3a 285 POP_GS_EX
f0d96110 286.endm
1da177e4 287
f0d96110
TH		 288.macro RING0_INT_FRAME
289 CFI_STARTPROC simple
290 CFI_SIGNAL_FRAME
291 CFI_DEF_CFA esp, 3*4
292 /*CFI_OFFSET cs, -2*4;*/
fe7cacc1 293 CFI_OFFSET eip, -3*4
f0d96110 294.endm
fe7cacc1 295
f0d96110
TH		 296.macro RING0_EC_FRAME
297 CFI_STARTPROC simple
298 CFI_SIGNAL_FRAME
299 CFI_DEF_CFA esp, 4*4
300 /*CFI_OFFSET cs, -2*4;*/
fe7cacc1 301 CFI_OFFSET eip, -3*4
f0d96110 302.endm
fe7cacc1 303
f0d96110
TH		 304.macro RING0_PTREGS_FRAME
305 CFI_STARTPROC simple
306 CFI_SIGNAL_FRAME
307 CFI_DEF_CFA esp, PT_OLDESP-PT_EBX
308 /*CFI_OFFSET cs, PT_CS-PT_OLDESP;*/
309 CFI_OFFSET eip, PT_EIP-PT_OLDESP
310 /*CFI_OFFSET es, PT_ES-PT_OLDESP;*/
311 /*CFI_OFFSET ds, PT_DS-PT_OLDESP;*/
312 CFI_OFFSET eax, PT_EAX-PT_OLDESP
313 CFI_OFFSET ebp, PT_EBP-PT_OLDESP
314 CFI_OFFSET edi, PT_EDI-PT_OLDESP
315 CFI_OFFSET esi, PT_ESI-PT_OLDESP
316 CFI_OFFSET edx, PT_EDX-PT_OLDESP
317 CFI_OFFSET ecx, PT_ECX-PT_OLDESP
eb5b7b9d 318 CFI_OFFSET ebx, PT_EBX-PT_OLDESP
f0d96110 319.endm
1da177e4
LT		 320
321ENTRY(ret_from_fork)
fe7cacc1 322 CFI_STARTPROC
1da177e4 323 pushl %eax
25d7dfda 324 CFI_ADJUST_CFA_OFFSET 4
1da177e4
LT		 325 call schedule_tail
326 GET_THREAD_INFO(%ebp)
327 popl %eax
fe7cacc1 328 CFI_ADJUST_CFA_OFFSET -4
47a5c6fa
LT		 329 pushl $0x0202 # Reset kernel eflags
330 CFI_ADJUST_CFA_OFFSET 4
331 popfl
332 CFI_ADJUST_CFA_OFFSET -4
1da177e4 333 jmp syscall_exit
fe7cacc1 334 CFI_ENDPROC
47a55cd7 335END(ret_from_fork)
1da177e4 336
a00e817f
MH		 337/*
338 * Interrupt exit functions should be protected against kprobes
339 */
340 .pushsection .kprobes.text, "ax"
1da177e4
LT		 341/*
342 * Return to user mode is not as complex as all this looks,
343 * but we want the default path for a system call return to
344 * go as quickly as possible which is why some of this is
345 * less clear than it otherwise should be.
346 */
347
348 # userspace resumption stub bypassing syscall exit tracing
349 ALIGN
fe7cacc1 350 RING0_PTREGS_FRAME
1da177e4 351ret_from_exception:
139ec7c4 352 preempt_stop(CLBR_ANY)
1da177e4
LT		 353ret_from_intr:
354 GET_THREAD_INFO(%ebp)
4031ff38 355check_userspace:
eb5b7b9d
JF		 356 movl PT_EFLAGS(%esp), %eax # mix EFLAGS and CS
357 movb PT_CS(%esp), %al
ab68ed98 358 andl $(X86_EFLAGS_VM | SEGMENT_RPL_MASK), %eax
78be3706
RR		 359 cmpl $USER_RPL, %eax
360 jb resume_kernel # not returning to v8086 or userspace
f95d47ca 361
1da177e4 362ENTRY(resume_userspace)
c7e872e7 363 LOCKDEP_SYS_EXIT
139ec7c4 364 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
1da177e4
LT		 365 # setting need_resched or sigpending
366 # between sampling and the iret
e32e58a9 367 TRACE_IRQS_OFF
1da177e4
LT		 368 movl TI_flags(%ebp), %ecx
369 andl $_TIF_WORK_MASK, %ecx # is there any work to be done on
370 # int/exception return?
371 jne work_pending
372 jmp restore_all
47a55cd7 373END(ret_from_exception)
1da177e4
LT		 374
375#ifdef CONFIG_PREEMPT
376ENTRY(resume_kernel)
139ec7c4 377 DISABLE_INTERRUPTS(CLBR_ANY)
1da177e4 378 cmpl $0,TI_preempt_count(%ebp) # non-zero preempt_count ?
2e04bc76 379 jnz restore_all
1da177e4
LT		 380need_resched:
381 movl TI_flags(%ebp), %ecx # need_resched set ?
382 testb $_TIF_NEED_RESCHED, %cl
383 jz restore_all
ab68ed98 384 testl $X86_EFLAGS_IF,PT_EFLAGS(%esp) # interrupts off (exception path) ?
1da177e4
LT		 385 jz restore_all
386 call preempt_schedule_irq
387 jmp need_resched
47a55cd7 388END(resume_kernel)
1da177e4 389#endif
fe7cacc1 390 CFI_ENDPROC
a00e817f
MH		 391/*
392 * End of kprobes section
393 */
394 .popsection
1da177e4
LT		 395
396/* SYSENTER_RETURN points to after the "sysenter" instruction in
397 the vsyscall page. See vsyscall-sysentry.S, which defines the symbol. */
398
399 # sysenter call handler stub
0aa97fb2 400ENTRY(ia32_sysenter_target)
fe7cacc1 401 CFI_STARTPROC simple
adf14236 402 CFI_SIGNAL_FRAME
fe7cacc1
JB		 403 CFI_DEF_CFA esp, 0
404 CFI_REGISTER esp, ebp
faca6227 405 movl TSS_sysenter_sp0(%esp),%esp
1da177e4 406sysenter_past_esp:
55f327fa 407 /*
d93c870b
JF		 408 * Interrupts are disabled here, but we can't trace it until
409 * enough kernel state to call TRACE_IRQS_OFF can be called - but
410 * we immediately enable interrupts at that point anyway.
55f327fa 411 */
1da177e4 412 pushl $(__USER_DS)
fe7cacc1
JB		 413 CFI_ADJUST_CFA_OFFSET 4
414 /*CFI_REL_OFFSET ss, 0*/
1da177e4 415 pushl %ebp
fe7cacc1
JB		 416 CFI_ADJUST_CFA_OFFSET 4
417 CFI_REL_OFFSET esp, 0
1da177e4 418 pushfl
d93c870b 419 orl $X86_EFLAGS_IF, (%esp)
fe7cacc1 420 CFI_ADJUST_CFA_OFFSET 4
1da177e4 421 pushl $(__USER_CS)
fe7cacc1
JB		 422 CFI_ADJUST_CFA_OFFSET 4
423 /*CFI_REL_OFFSET cs, 0*/
e6e5494c
IM		 424 /*
425 * Push current_thread_info()->sysenter_return to the stack.
426 * A tiny bit of offset fixup is necessary - 4*4 means the 4 words
427 * pushed above; +8 corresponds to copy_thread's esp0 setting.
428 */
429 pushl (TI_sysenter_return-THREAD_SIZE+8+4*4)(%esp)
fe7cacc1
JB		 430 CFI_ADJUST_CFA_OFFSET 4
431 CFI_REL_OFFSET eip, 0
1da177e4 432
d93c870b
JF		 433 pushl %eax
434 CFI_ADJUST_CFA_OFFSET 4
435 SAVE_ALL
436 ENABLE_INTERRUPTS(CLBR_NONE)
437
1da177e4
LT		 438/*
439 * Load the potential sixth argument from user stack.
440 * Careful about security.
441 */
442 cmpl $__PAGE_OFFSET-3,%ebp
443 jae syscall_fault
4441: movl (%ebp),%ebp
d93c870b 445 movl %ebp,PT_EBP(%esp)
1da177e4
LT		 446.section __ex_table,"a"
447 .align 4
448 .long 1b,syscall_fault
449.previous
450
1da177e4
LT		 451 GET_THREAD_INFO(%ebp)
452
88200bc2 453 testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%ebp)
af0575bb
RM		 454 jnz sysenter_audit
455sysenter_do_call:
1da177e4
LT		 456 cmpl $(nr_syscalls), %eax
457 jae syscall_badsys
458 call *sys_call_table(,%eax,4)
eb5b7b9d 459 movl %eax,PT_EAX(%esp)
c7e872e7 460 LOCKDEP_SYS_EXIT
42c24fa2 461 DISABLE_INTERRUPTS(CLBR_ANY)
55f327fa 462 TRACE_IRQS_OFF
1da177e4 463 movl TI_flags(%ebp), %ecx
88200bc2 464 testl $_TIF_ALLWORK_MASK, %ecx
af0575bb
RM		 465 jne sysexit_audit
466sysenter_exit:
1da177e4 467/* if something modifies registers it must also disable sysexit */
eb5b7b9d
JF		 468 movl PT_EIP(%esp), %edx
469 movl PT_OLDESP(%esp), %ecx
1da177e4 470 xorl %ebp,%ebp
55f327fa 471 TRACE_IRQS_ON
464d1a78 4721: mov PT_FS(%esp), %fs
ccbeed3a 473 PTGS_TO_GS
d75cd22f 474 ENABLE_INTERRUPTS_SYSEXIT
af0575bb
RM		 475
476#ifdef CONFIG_AUDITSYSCALL
477sysenter_audit:
88200bc2 478 testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
af0575bb
RM		 479 jnz syscall_trace_entry
480 addl $4,%esp
481 CFI_ADJUST_CFA_OFFSET -4
482 /* %esi already in 8(%esp) 6th arg: 4th syscall arg */
483 /* %edx already in 4(%esp) 5th arg: 3rd syscall arg */
484 /* %ecx already in 0(%esp) 4th arg: 2nd syscall arg */
485 movl %ebx,%ecx /* 3rd arg: 1st syscall arg */
486 movl %eax,%edx /* 2nd arg: syscall number */
487 movl $AUDIT_ARCH_I386,%eax /* 1st arg: audit arch */
488 call audit_syscall_entry
489 pushl %ebx
490 CFI_ADJUST_CFA_OFFSET 4
491 movl PT_EAX(%esp),%eax /* reload syscall number */
492 jmp sysenter_do_call
493
494sysexit_audit:
88200bc2 495 testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %ecx
af0575bb
RM		 496 jne syscall_exit_work
497 TRACE_IRQS_ON
498 ENABLE_INTERRUPTS(CLBR_ANY)
499 movl %eax,%edx /* second arg, syscall return value */
500 cmpl $0,%eax /* is it < 0? */
501 setl %al /* 1 if so, 0 if not */
502 movzbl %al,%eax /* zero-extend that */
503 inc %eax /* first arg, 0->1(AUDITSC_SUCCESS), 1->2(AUDITSC_FAILURE) */
504 call audit_syscall_exit
505 DISABLE_INTERRUPTS(CLBR_ANY)
506 TRACE_IRQS_OFF
507 movl TI_flags(%ebp), %ecx
88200bc2 508 testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %ecx
af0575bb
RM		 509 jne syscall_exit_work
510 movl PT_EAX(%esp),%eax /* reload syscall return value */
511 jmp sysenter_exit
512#endif
513
fe7cacc1 514 CFI_ENDPROC
f95d47ca 515.pushsection .fixup,"ax"
464d1a78 5162: movl $0,PT_FS(%esp)
f95d47ca
JF		 517 jmp 1b
518.section __ex_table,"a"
519 .align 4
520 .long 1b,2b
521.popsection
ccbeed3a 522 PTGS_TO_GS_EX
0aa97fb2 523ENDPROC(ia32_sysenter_target)
1da177e4 524
a00e817f
MH		 525/*
526 * syscall stub including irq exit should be protected against kprobes
527 */
528 .pushsection .kprobes.text, "ax"
1da177e4
LT		 529 # system call handler stub
530ENTRY(system_call)
fe7cacc1 531 RING0_INT_FRAME # can't unwind into user space anyway
1da177e4 532 pushl %eax # save orig_eax
fe7cacc1 533 CFI_ADJUST_CFA_OFFSET 4
1da177e4
LT		 534 SAVE_ALL
535 GET_THREAD_INFO(%ebp)
ed75e8d5 536 # system call tracing in operation / emulation
88200bc2 537 testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%ebp)
1da177e4
LT		 538 jnz syscall_trace_entry
539 cmpl $(nr_syscalls), %eax
540 jae syscall_badsys
541syscall_call:
542 call *sys_call_table(,%eax,4)
eb5b7b9d 543 movl %eax,PT_EAX(%esp) # store the return value
1da177e4 544syscall_exit:
c7e872e7 545 LOCKDEP_SYS_EXIT
139ec7c4 546 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
1da177e4
LT		 547 # setting need_resched or sigpending
548 # between sampling and the iret
55f327fa 549 TRACE_IRQS_OFF
1da177e4 550 movl TI_flags(%ebp), %ecx
88200bc2 551 testl $_TIF_ALLWORK_MASK, %ecx # current->work
1da177e4
LT		 552 jne syscall_exit_work
553
554restore_all:
2e04bc76
AH		 555 TRACE_IRQS_IRET
556restore_all_notrace:
eb5b7b9d
JF		 557 movl PT_EFLAGS(%esp), %eax # mix EFLAGS, SS and CS
558 # Warning: PT_OLDSS(%esp) contains the wrong/random values if we
5df24082
SS		 559 # are returning to the kernel.
560 # See comments in process.c:copy_thread() for details.
eb5b7b9d
JF		 561 movb PT_OLDSS(%esp), %ah
562 movb PT_CS(%esp), %al
ab68ed98 563 andl $(X86_EFLAGS_VM | (SEGMENT_TI_MASK << 8) | SEGMENT_RPL_MASK), %eax
78be3706 564 cmpl $((SEGMENT_LDT << 8) | USER_RPL), %eax
fe7cacc1 565 CFI_REMEMBER_STATE
1da177e4
LT		 566 je ldt_ss # returning to user-space with LDT SS
567restore_nocheck:
ccbeed3a 568 RESTORE_REGS 4 # skip orig_eax/error_code
fe7cacc1 569 CFI_ADJUST_CFA_OFFSET -4
f7f3d791 570irq_return:
3701d863 571 INTERRUPT_RETURN
1da177e4 572.section .fixup,"ax"
90e9f536 573ENTRY(iret_exc)
a879cbbb
LT		 574 pushl $0 # no error code
575 pushl $do_iret_error
576 jmp error_code
1da177e4
LT		 577.previous
578.section __ex_table,"a"
579 .align 4
3701d863 580 .long irq_return,iret_exc
1da177e4
LT		 581.previous
582
fe7cacc1 583 CFI_RESTORE_STATE
1da177e4 584ldt_ss:
eb5b7b9d 585 larl PT_OLDSS(%esp), %eax
1da177e4
LT		 586 jnz restore_nocheck
587 testl $0x00400000, %eax # returning to 32bit stack?
588 jnz restore_nocheck # allright, normal return
d3561b7f
RR		 589
590#ifdef CONFIG_PARAVIRT
591 /*
592 * The kernel can't run on a non-flat stack if paravirt mode
593 * is active. Rather than try to fixup the high bits of
594 * ESP, bypass this code entirely. This may break DOSemu
595 * and/or Wine support in a paravirt VM, although the option
596 * is still available to implement the setting of the high
597 * 16-bits in the INTERRUPT_RETURN paravirt-op.
598 */
93b1eab3 599 cmpl $0, pv_info+PARAVIRT_enabled
d3561b7f
RR		 600 jne restore_nocheck
601#endif
602
dc4c2a0a
AH		 603/*
604 * Setup and switch to ESPFIX stack
605 *
606 * We're returning to userspace with a 16 bit stack. The CPU will not
607 * restore the high word of ESP for us on executing iret... This is an
608 * "official" bug of all the x86-compatible CPUs, which we can work
609 * around to make dosemu and wine happy. We do this by preloading the
610 * high word of ESP with the high word of the userspace ESP while
611 * compensating for the offset by changing to the ESPFIX segment with
612 * a base address that matches for the difference.
613 */
614 mov %esp, %edx /* load kernel esp */
615 mov PT_OLDESP(%esp), %eax /* load userspace esp */
616 mov %dx, %ax /* eax: new kernel esp */
617 sub %eax, %edx /* offset (low word is 0) */
618 PER_CPU(gdt_page, %ebx)
619 shr $16, %edx
620 mov %dl, GDT_ENTRY_ESPFIX_SS * 8 + 4(%ebx) /* bits 16..23 */
621 mov %dh, GDT_ENTRY_ESPFIX_SS * 8 + 7(%ebx) /* bits 24..31 */
be44d2aa
SS		 622 pushl $__ESPFIX_SS
623 CFI_ADJUST_CFA_OFFSET 4
dc4c2a0a 624 push %eax /* new kernel esp */
be44d2aa 625 CFI_ADJUST_CFA_OFFSET 4
2e04bc76
AH		 626 /* Disable interrupts, but do not irqtrace this section: we
627 * will soon execute iret and the tracer was already set to
628 * the irqstate after the iret */
139ec7c4 629 DISABLE_INTERRUPTS(CLBR_EAX)
dc4c2a0a 630 lss (%esp), %esp /* switch to espfix segment */
be44d2aa
SS		 631 CFI_ADJUST_CFA_OFFSET -8
632 jmp restore_nocheck
fe7cacc1 633 CFI_ENDPROC
47a55cd7 634ENDPROC(system_call)
1da177e4
LT		 635
636 # perform work that needs to be done immediately before resumption
637 ALIGN
fe7cacc1 638 RING0_PTREGS_FRAME # can't unwind into user space anyway
1da177e4
LT		 639work_pending:
640 testb $_TIF_NEED_RESCHED, %cl
641 jz work_notifysig
642work_resched:
643 call schedule
c7e872e7 644 LOCKDEP_SYS_EXIT
139ec7c4 645 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
1da177e4
LT		 646 # setting need_resched or sigpending
647 # between sampling and the iret
55f327fa 648 TRACE_IRQS_OFF
1da177e4
LT		 649 movl TI_flags(%ebp), %ecx
650 andl $_TIF_WORK_MASK, %ecx # is there any work to be done other
651 # than syscall tracing?
652 jz restore_all
653 testb $_TIF_NEED_RESCHED, %cl
654 jnz work_resched
655
656work_notifysig: # deal with pending signals and
657 # notify-resume requests
74b47a78 658#ifdef CONFIG_VM86
ab68ed98 659 testl $X86_EFLAGS_VM, PT_EFLAGS(%esp)
1da177e4
LT		 660 movl %esp, %eax
661 jne work_notifysig_v86 # returning to kernel-space or
662 # vm86-space
663 xorl %edx, %edx
664 call do_notify_resume
4031ff38 665 jmp resume_userspace_sig
1da177e4
LT		 666
667 ALIGN
668work_notifysig_v86:
669 pushl %ecx # save ti_flags for do_notify_resume
fe7cacc1 670 CFI_ADJUST_CFA_OFFSET 4
1da177e4
LT		 671 call save_v86_state # %eax contains pt_regs pointer
672 popl %ecx
fe7cacc1 673 CFI_ADJUST_CFA_OFFSET -4
1da177e4 674 movl %eax, %esp
74b47a78
JK		 675#else
676 movl %esp, %eax
677#endif
1da177e4
LT		 678 xorl %edx, %edx
679 call do_notify_resume
4031ff38 680 jmp resume_userspace_sig
47a55cd7 681END(work_pending)
1da177e4
LT		 682
683 # perform syscall exit tracing
684 ALIGN
685syscall_trace_entry:
eb5b7b9d 686 movl $-ENOSYS,PT_EAX(%esp)
1da177e4 687 movl %esp, %eax
d4d67150
RM		 688 call syscall_trace_enter
689 /* What it returned is what we'll actually use. */
1da177e4
LT		 690 cmpl $(nr_syscalls), %eax
691 jnae syscall_call
692 jmp syscall_exit
47a55cd7 693END(syscall_trace_entry)
1da177e4
LT		 694
695 # perform syscall exit tracing
696 ALIGN
697syscall_exit_work:
88200bc2 698 testl $_TIF_WORK_SYSCALL_EXIT, %ecx
1da177e4 699 jz work_pending
55f327fa 700 TRACE_IRQS_ON
d4d67150 701 ENABLE_INTERRUPTS(CLBR_ANY) # could let syscall_trace_leave() call
1da177e4
LT		 702 # schedule() instead
703 movl %esp, %eax
d4d67150 704 call syscall_trace_leave
1da177e4 705 jmp resume_userspace
47a55cd7 706END(syscall_exit_work)
fe7cacc1 707 CFI_ENDPROC
1da177e4 708
fe7cacc1 709 RING0_INT_FRAME # can't unwind into user space anyway
1da177e4 710syscall_fault:
1da177e4 711 GET_THREAD_INFO(%ebp)
eb5b7b9d 712 movl $-EFAULT,PT_EAX(%esp)
1da177e4 713 jmp resume_userspace
47a55cd7 714END(syscall_fault)
1da177e4 715
1da177e4 716syscall_badsys:
eb5b7b9d 717 movl $-ENOSYS,PT_EAX(%esp)
1da177e4 718 jmp resume_userspace
47a55cd7 719END(syscall_badsys)
fe7cacc1 720 CFI_ENDPROC
a00e817f
MH		 721/*
722 * End of kprobes section
723 */
724 .popsection
1da177e4 725
253f29a4
BG		 726/*
727 * System calls that need a pt_regs pointer.
728 */
e258e4e0 729#define PTREGSCALL0(name) \
253f29a4
BG		 730 ALIGN; \
731ptregs_##name: \
732 leal 4(%esp),%eax; \
733 jmp sys_##name;
734
e258e4e0
BG		 735#define PTREGSCALL1(name) \
736 ALIGN; \
737ptregs_##name: \
738 leal 4(%esp),%edx; \
ce9119ad 739 movl (PT_EBX+4)(%esp),%eax; \
e258e4e0
BG		 740 jmp sys_##name;
741
742#define PTREGSCALL2(name) \
743 ALIGN; \
744ptregs_##name: \
745 leal 4(%esp),%ecx; \
ce9119ad
PA		 746 movl (PT_ECX+4)(%esp),%edx; \
747 movl (PT_EBX+4)(%esp),%eax; \
e258e4e0
BG		 748 jmp sys_##name;
749
750#define PTREGSCALL3(name) \
751 ALIGN; \
752ptregs_##name: \
753 leal 4(%esp),%eax; \
754 pushl %eax; \
755 movl PT_EDX(%eax),%ecx; \
756 movl PT_ECX(%eax),%edx; \
757 movl PT_EBX(%eax),%eax; \
758 call sys_##name; \
759 addl $4,%esp; \
760 ret
761
27f59559 762PTREGSCALL1(iopl)
e258e4e0 763PTREGSCALL0(fork)
e258e4e0 764PTREGSCALL0(vfork)
11cf88bd 765PTREGSCALL3(execve)
052acad4 766PTREGSCALL2(sigaltstack)
e258e4e0
BG		 767PTREGSCALL0(sigreturn)
768PTREGSCALL0(rt_sigreturn)
f1382f15
BG		 769PTREGSCALL2(vm86)
770PTREGSCALL1(vm86old)
253f29a4 771
f839bbc5
BG		 772/* Clone is an oddball. The 4th arg is in %edi */
773 ALIGN;
774ptregs_clone:
775 leal 4(%esp),%eax
776 pushl %eax
777 pushl PT_EDI(%eax)
778 movl PT_EDX(%eax),%ecx
779 movl PT_ECX(%eax),%edx
780 movl PT_EBX(%eax),%eax
781 call sys_clone
782 addl $8,%esp
783 ret
784
f0d96110 785.macro FIXUP_ESPFIX_STACK
dc4c2a0a
AH		 786/*
787 * Switch back for ESPFIX stack to the normal zerobased stack
788 *
789 * We can't call C functions using the ESPFIX stack. This code reads
790 * the high word of the segment base from the GDT and swiches to the
791 * normal stack and adjusts ESP with the matching offset.
792 */
793 /* fixup the stack */
f0d96110 794 PER_CPU(gdt_page, %ebx)
dc4c2a0a
AH		 795 mov GDT_ENTRY_ESPFIX_SS * 8 + 4(%ebx), %al /* bits 16..23 */
796 mov GDT_ENTRY_ESPFIX_SS * 8 + 7(%ebx), %ah /* bits 24..31 */
797 shl $16, %eax
798 addl %esp, %eax /* the adjusted stack pointer */
f0d96110
TH		 799 pushl $__KERNEL_DS
800 CFI_ADJUST_CFA_OFFSET 4
801 pushl %eax
802 CFI_ADJUST_CFA_OFFSET 4
dc4c2a0a 803 lss (%esp), %esp /* switch to the normal stack segment */
f0d96110
TH		 804 CFI_ADJUST_CFA_OFFSET -8
805.endm
806.macro UNWIND_ESPFIX_STACK
807 movl %ss, %eax
808 /* see if on espfix stack */
809 cmpw $__ESPFIX_SS, %ax
810 jne 27f
811 movl $__KERNEL_DS, %eax
812 movl %eax, %ds
813 movl %eax, %es
814 /* switch to normal stack */
815 FIXUP_ESPFIX_STACK
81627:
817.endm
1da177e4
LT		 818
819/*
b7c6244f
PA		 820 * Build the entry stubs and pointer table with some assembler magic.
821 * We pack 7 stubs into a single 32-byte chunk, which will fit in a
822 * single cache line on all modern x86 implementations.
1da177e4 823 */
4687518c 824.section .init.rodata,"a"
1da177e4
LT		 825ENTRY(interrupt)
826.text
b7c6244f
PA		 827 .p2align 5
828 .p2align CONFIG_X86_L1_CACHE_SHIFT
1da177e4 829ENTRY(irq_entries_start)
fe7cacc1 830 RING0_INT_FRAME
4687518c 831vector=FIRST_EXTERNAL_VECTOR
b7c6244f
PA		 832.rept (NR_VECTORS-FIRST_EXTERNAL_VECTOR+6)/7
833 .balign 32
834 .rept 7
835 .if vector < NR_VECTORS
8665596e 836 .if vector <> FIRST_EXTERNAL_VECTOR
fe7cacc1 837 CFI_ADJUST_CFA_OFFSET -4
b7c6244f
PA		 838 .endif
8391: pushl $(~vector+0x80) /* Note: always in signed byte range */
fe7cacc1 840 CFI_ADJUST_CFA_OFFSET 4
8665596e 841 .if ((vector-FIRST_EXTERNAL_VECTOR)%7) <> 6
b7c6244f
PA		 842 jmp 2f
843 .endif
844 .previous
1da177e4 845 .long 1b
b7c6244f 846 .text
1da177e4 847vector=vector+1
b7c6244f
PA		 848 .endif
849 .endr
8502: jmp common_interrupt
1da177e4 851.endr
47a55cd7
JB		 852END(irq_entries_start)
853
854.previous
855END(interrupt)
856.previous
1da177e4 857
55f327fa
IM		 858/*
859 * the CPU automatically disables interrupts when executing an IRQ vector,
860 * so IRQ-flags tracing has to follow that:
861 */
b7c6244f 862 .p2align CONFIG_X86_L1_CACHE_SHIFT
1da177e4 863common_interrupt:
b7c6244f 864 addl $-0x80,(%esp) /* Adjust vector into the [-256,-1] range */
1da177e4 865 SAVE_ALL
55f327fa 866 TRACE_IRQS_OFF
1da177e4
LT		 867 movl %esp,%eax
868 call do_IRQ
869 jmp ret_from_intr
47a55cd7 870ENDPROC(common_interrupt)
fe7cacc1 871 CFI_ENDPROC
1da177e4 872
a00e817f
MH		 873/*
874 * Irq entries should be protected against kprobes
875 */
876 .pushsection .kprobes.text, "ax"
02cf94c3 877#define BUILD_INTERRUPT3(name, nr, fn) \
1da177e4 878ENTRY(name) \
fe7cacc1 879 RING0_INT_FRAME; \
19eadf98 880 pushl $~(nr); \
fe7cacc1
JB		 881 CFI_ADJUST_CFA_OFFSET 4; \
882 SAVE_ALL; \
55f327fa 883 TRACE_IRQS_OFF \
1da177e4 884 movl %esp,%eax; \
02cf94c3 885 call fn; \
55f327fa 886 jmp ret_from_intr; \
47a55cd7
JB		 887 CFI_ENDPROC; \
888ENDPROC(name)
1da177e4 889
02cf94c3
TH		 890#define BUILD_INTERRUPT(name, nr) BUILD_INTERRUPT3(name, nr, smp_##name)
891
1da177e4 892/* The include is where all of the SMP etc. interrupts come from */
1164dd00 893#include <asm/entry_arch.h>
1da177e4 894
1da177e4 895ENTRY(coprocessor_error)
fe7cacc1 896 RING0_INT_FRAME
1da177e4 897 pushl $0
fe7cacc1 898 CFI_ADJUST_CFA_OFFSET 4
1da177e4 899 pushl $do_coprocessor_error
fe7cacc1 900 CFI_ADJUST_CFA_OFFSET 4
1da177e4 901 jmp error_code
fe7cacc1 902 CFI_ENDPROC
47a55cd7 903END(coprocessor_error)
1da177e4
LT		 904
905ENTRY(simd_coprocessor_error)
fe7cacc1 906 RING0_INT_FRAME
1da177e4 907 pushl $0
fe7cacc1 908 CFI_ADJUST_CFA_OFFSET 4
40d2e763
BG		 909#ifdef CONFIG_X86_INVD_BUG
910 /* AMD 486 bug: invd from userspace calls exception 19 instead of #GP */
911661: pushl $do_general_protection
912662:
913.section .altinstructions,"a"
914 .balign 4
915 .long 661b
916 .long 663f
917 .byte X86_FEATURE_XMM
918 .byte 662b-661b
919 .byte 664f-663f
920.previous
921.section .altinstr_replacement,"ax"
922663: pushl $do_simd_coprocessor_error
923664:
924.previous
925#else
1da177e4 926 pushl $do_simd_coprocessor_error
40d2e763 927#endif
fe7cacc1 928 CFI_ADJUST_CFA_OFFSET 4
1da177e4 929 jmp error_code
fe7cacc1 930 CFI_ENDPROC
47a55cd7 931END(simd_coprocessor_error)
1da177e4
LT		 932
933ENTRY(device_not_available)
fe7cacc1 934 RING0_INT_FRAME
1da177e4 935 pushl $-1 # mark this as an int
fe7cacc1 936 CFI_ADJUST_CFA_OFFSET 4
7643e9b9 937 pushl $do_device_not_available
fe7cacc1 938 CFI_ADJUST_CFA_OFFSET 4
7643e9b9 939 jmp error_code
fe7cacc1 940 CFI_ENDPROC
47a55cd7 941END(device_not_available)
1da177e4 942
d3561b7f
RR		 943#ifdef CONFIG_PARAVIRT
944ENTRY(native_iret)
3701d863 945 iret
d3561b7f
RR		 946.section __ex_table,"a"
947 .align 4
3701d863 948 .long native_iret, iret_exc
d3561b7f 949.previous
47a55cd7 950END(native_iret)
d3561b7f 951
d75cd22f 952ENTRY(native_irq_enable_sysexit)
d3561b7f
RR		 953 sti
954 sysexit
d75cd22f 955END(native_irq_enable_sysexit)
d3561b7f
RR		 956#endif
957
1da177e4 958ENTRY(overflow)
fe7cacc1 959 RING0_INT_FRAME
1da177e4 960 pushl $0
fe7cacc1 961 CFI_ADJUST_CFA_OFFSET 4
1da177e4 962 pushl $do_overflow
fe7cacc1 963 CFI_ADJUST_CFA_OFFSET 4
1da177e4 964 jmp error_code
fe7cacc1 965 CFI_ENDPROC
47a55cd7 966END(overflow)
1da177e4
LT		 967
968ENTRY(bounds)
fe7cacc1 969 RING0_INT_FRAME
1da177e4 970 pushl $0
fe7cacc1 971 CFI_ADJUST_CFA_OFFSET 4
1da177e4 972 pushl $do_bounds
fe7cacc1 973 CFI_ADJUST_CFA_OFFSET 4
1da177e4 974 jmp error_code
fe7cacc1 975 CFI_ENDPROC
47a55cd7 976END(bounds)
1da177e4
LT		 977
978ENTRY(invalid_op)
fe7cacc1 979 RING0_INT_FRAME
1da177e4 980 pushl $0
fe7cacc1 981 CFI_ADJUST_CFA_OFFSET 4
1da177e4 982 pushl $do_invalid_op
fe7cacc1 983 CFI_ADJUST_CFA_OFFSET 4
1da177e4 984 jmp error_code
fe7cacc1 985 CFI_ENDPROC
47a55cd7 986END(invalid_op)
1da177e4
LT		 987
988ENTRY(coprocessor_segment_overrun)
fe7cacc1 989 RING0_INT_FRAME
1da177e4 990 pushl $0
fe7cacc1 991 CFI_ADJUST_CFA_OFFSET 4
1da177e4 992 pushl $do_coprocessor_segment_overrun
fe7cacc1 993 CFI_ADJUST_CFA_OFFSET 4
1da177e4 994 jmp error_code
fe7cacc1 995 CFI_ENDPROC
47a55cd7 996END(coprocessor_segment_overrun)
1da177e4
LT		 997
998ENTRY(invalid_TSS)
fe7cacc1 999 RING0_EC_FRAME
1da177e4 1000 pushl $do_invalid_TSS
fe7cacc1 1001 CFI_ADJUST_CFA_OFFSET 4
1da177e4 1002 jmp error_code
fe7cacc1 1003 CFI_ENDPROC
47a55cd7 1004END(invalid_TSS)
1da177e4
LT		 1005
1006ENTRY(segment_not_present)
fe7cacc1 1007 RING0_EC_FRAME
1da177e4 1008 pushl $do_segment_not_present
fe7cacc1 1009 CFI_ADJUST_CFA_OFFSET 4
1da177e4 1010 jmp error_code
fe7cacc1 1011 CFI_ENDPROC
47a55cd7 1012END(segment_not_present)
1da177e4
LT		 1013
1014ENTRY(stack_segment)
fe7cacc1 1015 RING0_EC_FRAME
1da177e4 1016 pushl $do_stack_segment
fe7cacc1 1017 CFI_ADJUST_CFA_OFFSET 4
1da177e4 1018 jmp error_code
fe7cacc1 1019 CFI_ENDPROC
47a55cd7 1020END(stack_segment)
1da177e4 1021
1da177e4 1022ENTRY(alignment_check)
fe7cacc1 1023 RING0_EC_FRAME
1da177e4 1024 pushl $do_alignment_check
fe7cacc1 1025 CFI_ADJUST_CFA_OFFSET 4
1da177e4 1026 jmp error_code
fe7cacc1 1027 CFI_ENDPROC
47a55cd7 1028END(alignment_check)
1da177e4 1029
d28c4393
P		 1030ENTRY(divide_error)
1031 RING0_INT_FRAME
1032 pushl $0 # no error code
1033 CFI_ADJUST_CFA_OFFSET 4
1034 pushl $do_divide_error
fe7cacc1 1035 CFI_ADJUST_CFA_OFFSET 4
1da177e4 1036 jmp error_code
fe7cacc1 1037 CFI_ENDPROC
47a55cd7 1038END(divide_error)
1da177e4
LT		 1039
1040#ifdef CONFIG_X86_MCE
1041ENTRY(machine_check)
fe7cacc1 1042 RING0_INT_FRAME
1da177e4 1043 pushl $0
fe7cacc1 1044 CFI_ADJUST_CFA_OFFSET 4
d2f6f7ae 1045 pushl machine_check_vector
fe7cacc1 1046 CFI_ADJUST_CFA_OFFSET 4
1da177e4 1047 jmp error_code
fe7cacc1 1048 CFI_ENDPROC
47a55cd7 1049END(machine_check)
1da177e4
LT		 1050#endif
1051
1052ENTRY(spurious_interrupt_bug)
fe7cacc1 1053 RING0_INT_FRAME
1da177e4 1054 pushl $0
fe7cacc1 1055 CFI_ADJUST_CFA_OFFSET 4
1da177e4 1056 pushl $do_spurious_interrupt_bug
fe7cacc1 1057 CFI_ADJUST_CFA_OFFSET 4
1da177e4 1058 jmp error_code
fe7cacc1 1059 CFI_ENDPROC
47a55cd7 1060END(spurious_interrupt_bug)
a00e817f
MH		 1061/*
1062 * End of kprobes section
1063 */
1064 .popsection
1da177e4 1065
02ba1a32
AK		 1066ENTRY(kernel_thread_helper)
1067 pushl $0 # fake return address for unwinder
1068 CFI_STARTPROC
e840227c
BG		 1069 movl %edi,%eax
1070 call *%esi
02ba1a32 1071 call do_exit
5f5db591 1072 ud2 # padding for call trace
02ba1a32
AK		 1073 CFI_ENDPROC
1074ENDPROC(kernel_thread_helper)
1075
5ead97c8 1076#ifdef CONFIG_XEN
e2a81baf
JF		 1077/* Xen doesn't set %esp to be precisely what the normal sysenter
1078 entrypoint expects, so fix it up before using the normal path. */
1079ENTRY(xen_sysenter_target)
1080 RING0_INT_FRAME
1081 addl $5*4, %esp /* remove xen-provided frame */
2ddf9b7b 1082 CFI_ADJUST_CFA_OFFSET -5*4
e2a81baf 1083 jmp sysenter_past_esp
557d7d4e 1084 CFI_ENDPROC
e2a81baf 1085
5ead97c8
JF		 1086ENTRY(xen_hypervisor_callback)
1087 CFI_STARTPROC
1088 pushl $0
1089 CFI_ADJUST_CFA_OFFSET 4
1090 SAVE_ALL
1091 TRACE_IRQS_OFF
9ec2b804
JF		 1092
1093 /* Check to see if we got the event in the critical
1094 region in xen_iret_direct, after we've reenabled
1095 events and checked for pending events. This simulates
1096 iret instruction's behaviour where it delivers a
1097 pending interrupt when enabling interrupts. */
1098 movl PT_EIP(%esp),%eax
1099 cmpl $xen_iret_start_crit,%eax
1100 jb 1f
1101 cmpl $xen_iret_end_crit,%eax
1102 jae 1f
1103
0f2c8769 1104 jmp xen_iret_crit_fixup
e2a81baf 1105
e2a81baf 1106ENTRY(xen_do_upcall)
b77797fb 11071: mov %esp, %eax
5ead97c8
JF		 1108 call xen_evtchn_do_upcall
1109 jmp ret_from_intr
1110 CFI_ENDPROC
1111ENDPROC(xen_hypervisor_callback)
1112
1113# Hypervisor uses this for application faults while it executes.
1114# We get here for two reasons:
1115# 1. Fault while reloading DS, ES, FS or GS
1116# 2. Fault while executing IRET
1117# Category 1 we fix up by reattempting the load, and zeroing the segment
1118# register if the load fails.
1119# Category 2 we fix up by jumping to do_iret_error. We cannot use the
1120# normal Linux return path in this case because if we use the IRET hypercall
1121# to pop the stack frame we end up in an infinite loop of failsafe callbacks.
1122# We distinguish between categories by maintaining a status value in EAX.
1123ENTRY(xen_failsafe_callback)
1124 CFI_STARTPROC
1125 pushl %eax
1126 CFI_ADJUST_CFA_OFFSET 4
1127 movl $1,%eax
11281: mov 4(%esp),%ds
11292: mov 8(%esp),%es
11303: mov 12(%esp),%fs
11314: mov 16(%esp),%gs
1132 testl %eax,%eax
1133 popl %eax
1134 CFI_ADJUST_CFA_OFFSET -4
1135 lea 16(%esp),%esp
1136 CFI_ADJUST_CFA_OFFSET -16
1137 jz 5f
1138 addl $16,%esp
1139 jmp iret_exc # EAX != 0 => Category 2 (Bad IRET)
11405: pushl $0 # EAX == 0 => Category 1 (Bad segment)
1141 CFI_ADJUST_CFA_OFFSET 4
1142 SAVE_ALL
1143 jmp ret_from_exception
1144 CFI_ENDPROC
1145
1146.section .fixup,"ax"
11476: xorl %eax,%eax
1148 movl %eax,4(%esp)
1149 jmp 1b
11507: xorl %eax,%eax
1151 movl %eax,8(%esp)
1152 jmp 2b
11538: xorl %eax,%eax
1154 movl %eax,12(%esp)
1155 jmp 3b
11569: xorl %eax,%eax
1157 movl %eax,16(%esp)
1158 jmp 4b
1159.previous
1160.section __ex_table,"a"
1161 .align 4
1162 .long 1b,6b
1163 .long 2b,7b
1164 .long 3b,8b
1165 .long 4b,9b
1166.previous
1167ENDPROC(xen_failsafe_callback)
1168
1169#endif /* CONFIG_XEN */
1170
606576ce 1171#ifdef CONFIG_FUNCTION_TRACER
d61f82d0
SR		 1172#ifdef CONFIG_DYNAMIC_FTRACE
1173
1174ENTRY(mcount)
d61f82d0
SR		 1175 ret
1176END(mcount)
1177
1178ENTRY(ftrace_caller)
60a7ecf4
SR		 1179 cmpl $0, function_trace_stop
1180 jne ftrace_stub
1181
d61f82d0
SR		 1182 pushl %eax
1183 pushl %ecx
1184 pushl %edx
1185 movl 0xc(%esp), %eax
1186 movl 0x4(%ebp), %edx
395a59d0 1187 subl $MCOUNT_INSN_SIZE, %eax
d61f82d0
SR		 1188
1189.globl ftrace_call
1190ftrace_call:
1191 call ftrace_stub
1192
1193 popl %edx
1194 popl %ecx
1195 popl %eax
5a45cfe1
SR		 1196#ifdef CONFIG_FUNCTION_GRAPH_TRACER
1197.globl ftrace_graph_call
1198ftrace_graph_call:
1199 jmp ftrace_stub
1200#endif
d61f82d0
SR		 1201
1202.globl ftrace_stub
1203ftrace_stub:
1204 ret
1205END(ftrace_caller)
1206
1207#else /* ! CONFIG_DYNAMIC_FTRACE */
1208
16444a8a 1209ENTRY(mcount)
60a7ecf4
SR		 1210 cmpl $0, function_trace_stop
1211 jne ftrace_stub
1212
16444a8a
ACM		 1213 cmpl $ftrace_stub, ftrace_trace_function
1214 jnz trace
fb52607a 1215#ifdef CONFIG_FUNCTION_GRAPH_TRACER
c2324b69 1216 cmpl $ftrace_stub, ftrace_graph_return
fb52607a 1217 jnz ftrace_graph_caller
e49dc19c
SR		 1218
1219 cmpl $ftrace_graph_entry_stub, ftrace_graph_entry
1220 jnz ftrace_graph_caller
caf4b323 1221#endif
16444a8a
ACM		 1222.globl ftrace_stub
1223ftrace_stub:
1224 ret
1225
1226 /* taken from glibc */
1227trace:
1228 pushl %eax
1229 pushl %ecx
1230 pushl %edx
1231 movl 0xc(%esp), %eax
1232 movl 0x4(%ebp), %edx
395a59d0 1233 subl $MCOUNT_INSN_SIZE, %eax
16444a8a 1234
d61f82d0 1235 call *ftrace_trace_function
16444a8a
ACM		 1236
1237 popl %edx
1238 popl %ecx
1239 popl %eax
16444a8a
ACM		 1240 jmp ftrace_stub
1241END(mcount)
d61f82d0 1242#endif /* CONFIG_DYNAMIC_FTRACE */
606576ce 1243#endif /* CONFIG_FUNCTION_TRACER */
16444a8a 1244
fb52607a
FW		 1245#ifdef CONFIG_FUNCTION_GRAPH_TRACER
1246ENTRY(ftrace_graph_caller)
e7d3737e
FW		 1247 cmpl $0, function_trace_stop
1248 jne ftrace_stub
1249
caf4b323
FW		 1250 pushl %eax
1251 pushl %ecx
1252 pushl %edx
1dc1c6ad 1253 movl 0xc(%esp), %edx
caf4b323 1254 lea 0x4(%ebp), %eax
71e308a2 1255 movl (%ebp), %ecx
bb4304c7 1256 subl $MCOUNT_INSN_SIZE, %edx
caf4b323 1257 call prepare_ftrace_return
caf4b323
FW		 1258 popl %edx
1259 popl %ecx
1260 popl %eax
e7d3737e 1261 ret
fb52607a 1262END(ftrace_graph_caller)
caf4b323
FW		 1263
1264.globl return_to_handler
1265return_to_handler:
caf4b323 1266 pushl %eax
caf4b323 1267 pushl %edx
71e308a2 1268 movl %ebp, %eax
caf4b323 1269 call ftrace_return_to_handler
194ec341 1270 movl %eax, %ecx
caf4b323 1271 popl %edx
caf4b323 1272 popl %eax
194ec341 1273 jmp *%ecx
e7d3737e 1274#endif
16444a8a 1275
bb152f53 1276.section .rodata,"a"
541054d9 1277#include "syscall_table_32.S"
1da177e4
LT		 1278
1279syscall_table_size=(.-sys_call_table)
d211af05
AH		 1280
1281/*
1282 * Some functions should be protected against kprobes
1283 */
1284 .pushsection .kprobes.text, "ax"
1285
1286ENTRY(page_fault)
1287 RING0_EC_FRAME
1288 pushl $do_page_fault
1289 CFI_ADJUST_CFA_OFFSET 4
1290 ALIGN
1291error_code:
ccbeed3a
TH		 1292 /* the function address is in %gs's slot on the stack */
1293 pushl %fs
1294 CFI_ADJUST_CFA_OFFSET 4
1295 /*CFI_REL_OFFSET fs, 0*/
d211af05
AH		 1296 pushl %es
1297 CFI_ADJUST_CFA_OFFSET 4
1298 /*CFI_REL_OFFSET es, 0*/
1299 pushl %ds
1300 CFI_ADJUST_CFA_OFFSET 4
1301 /*CFI_REL_OFFSET ds, 0*/
1302 pushl %eax
1303 CFI_ADJUST_CFA_OFFSET 4
1304 CFI_REL_OFFSET eax, 0
1305 pushl %ebp
1306 CFI_ADJUST_CFA_OFFSET 4
1307 CFI_REL_OFFSET ebp, 0
1308 pushl %edi
1309 CFI_ADJUST_CFA_OFFSET 4
1310 CFI_REL_OFFSET edi, 0
1311 pushl %esi
1312 CFI_ADJUST_CFA_OFFSET 4
1313 CFI_REL_OFFSET esi, 0
1314 pushl %edx
1315 CFI_ADJUST_CFA_OFFSET 4
1316 CFI_REL_OFFSET edx, 0
1317 pushl %ecx
1318 CFI_ADJUST_CFA_OFFSET 4
1319 CFI_REL_OFFSET ecx, 0
1320 pushl %ebx
1321 CFI_ADJUST_CFA_OFFSET 4
1322 CFI_REL_OFFSET ebx, 0
1323 cld
d211af05
AH		 1324 movl $(__KERNEL_PERCPU), %ecx
1325 movl %ecx, %fs
1326 UNWIND_ESPFIX_STACK
ccbeed3a
TH		 1327 GS_TO_REG %ecx
1328 movl PT_GS(%esp), %edi # get the function address
d211af05
AH		 1329 movl PT_ORIG_EAX(%esp), %edx # get the error code
1330 movl $-1, PT_ORIG_EAX(%esp) # no syscall to restart
ccbeed3a
TH		 1331 REG_TO_PTGS %ecx
1332 SET_KERNEL_GS %ecx
d211af05
AH		 1333 movl $(__USER_DS), %ecx
1334 movl %ecx, %ds
1335 movl %ecx, %es
1336 TRACE_IRQS_OFF
1337 movl %esp,%eax # pt_regs pointer
1338 call *%edi
1339 jmp ret_from_exception
1340 CFI_ENDPROC
1341END(page_fault)
1342
1343/*
1344 * Debug traps and NMI can happen at the one SYSENTER instruction
1345 * that sets up the real kernel stack. Check here, since we can't
1346 * allow the wrong stack to be used.
1347 *
1348 * "TSS_sysenter_sp0+12" is because the NMI/debug handler will have
1349 * already pushed 3 words if it hits on the sysenter instruction:
1350 * eflags, cs and eip.
1351 *
1352 * We just load the right stack, and push the three (known) values
1353 * by hand onto the new stack - while updating the return eip past
1354 * the instruction that would have done it for sysenter.
1355 */
f0d96110
TH		 1356.macro FIX_STACK offset ok label
1357 cmpw $__KERNEL_CS, 4(%esp)
1358 jne \ok
1359\label:
1360 movl TSS_sysenter_sp0 + \offset(%esp), %esp
1361 CFI_DEF_CFA esp, 0
1362 CFI_UNDEFINED eip
1363 pushfl
1364 CFI_ADJUST_CFA_OFFSET 4
1365 pushl $__KERNEL_CS
1366 CFI_ADJUST_CFA_OFFSET 4
1367 pushl $sysenter_past_esp
1368 CFI_ADJUST_CFA_OFFSET 4
d211af05 1369 CFI_REL_OFFSET eip, 0
f0d96110 1370.endm
d211af05
AH		 1371
1372ENTRY(debug)
1373 RING0_INT_FRAME
1374 cmpl $ia32_sysenter_target,(%esp)
1375 jne debug_stack_correct
f0d96110 1376 FIX_STACK 12, debug_stack_correct, debug_esp_fix_insn
d211af05
AH		 1377debug_stack_correct:
1378 pushl $-1 # mark this as an int
1379 CFI_ADJUST_CFA_OFFSET 4
1380 SAVE_ALL
1381 TRACE_IRQS_OFF
1382 xorl %edx,%edx # error code 0
1383 movl %esp,%eax # pt_regs pointer
1384 call do_debug
1385 jmp ret_from_exception
1386 CFI_ENDPROC
1387END(debug)
1388
1389/*
1390 * NMI is doubly nasty. It can happen _while_ we're handling
1391 * a debug fault, and the debug fault hasn't yet been able to
1392 * clear up the stack. So we first check whether we got an
1393 * NMI on the sysenter entry path, but after that we need to
1394 * check whether we got an NMI on the debug path where the debug
1395 * fault happened on the sysenter path.
1396 */
1397ENTRY(nmi)
1398 RING0_INT_FRAME
1399 pushl %eax
1400 CFI_ADJUST_CFA_OFFSET 4
1401 movl %ss, %eax
1402 cmpw $__ESPFIX_SS, %ax
1403 popl %eax
1404 CFI_ADJUST_CFA_OFFSET -4
1405 je nmi_espfix_stack
1406 cmpl $ia32_sysenter_target,(%esp)
1407 je nmi_stack_fixup
1408 pushl %eax
1409 CFI_ADJUST_CFA_OFFSET 4
1410 movl %esp,%eax
1411 /* Do not access memory above the end of our stack page,
1412 * it might not exist.
1413 */
1414 andl $(THREAD_SIZE-1),%eax
1415 cmpl $(THREAD_SIZE-20),%eax
1416 popl %eax
1417 CFI_ADJUST_CFA_OFFSET -4
1418 jae nmi_stack_correct
1419 cmpl $ia32_sysenter_target,12(%esp)
1420 je nmi_debug_stack_check
1421nmi_stack_correct:
1422 /* We have a RING0_INT_FRAME here */
1423 pushl %eax
1424 CFI_ADJUST_CFA_OFFSET 4
1425 SAVE_ALL
d211af05
AH		 1426 xorl %edx,%edx # zero error code
1427 movl %esp,%eax # pt_regs pointer
1428 call do_nmi
2e04bc76 1429 jmp restore_all_notrace
d211af05
AH		 1430 CFI_ENDPROC
1431
1432nmi_stack_fixup:
1433 RING0_INT_FRAME
f0d96110 1434 FIX_STACK 12, nmi_stack_correct, 1
d211af05
AH		 1435 jmp nmi_stack_correct
1436
1437nmi_debug_stack_check:
1438 /* We have a RING0_INT_FRAME here */
1439 cmpw $__KERNEL_CS,16(%esp)
1440 jne nmi_stack_correct
1441 cmpl $debug,(%esp)
1442 jb nmi_stack_correct
1443 cmpl $debug_esp_fix_insn,(%esp)
1444 ja nmi_stack_correct
f0d96110 1445 FIX_STACK 24, nmi_stack_correct, 1
d211af05
AH		 1446 jmp nmi_stack_correct
1447
1448nmi_espfix_stack:
1449 /* We have a RING0_INT_FRAME here.
1450 *
1451 * create the pointer to lss back
1452 */
1453 pushl %ss
1454 CFI_ADJUST_CFA_OFFSET 4
1455 pushl %esp
1456 CFI_ADJUST_CFA_OFFSET 4
bda3a897 1457 addl $4, (%esp)
d211af05
AH		 1458 /* copy the iret frame of 12 bytes */
1459 .rept 3
1460 pushl 16(%esp)
1461 CFI_ADJUST_CFA_OFFSET 4
1462 .endr
1463 pushl %eax
1464 CFI_ADJUST_CFA_OFFSET 4
1465 SAVE_ALL
d211af05
AH		 1466 FIXUP_ESPFIX_STACK # %eax == %esp
1467 xorl %edx,%edx # zero error code
1468 call do_nmi
1469 RESTORE_REGS
1470 lss 12+4(%esp), %esp # back to espfix stack
1471 CFI_ADJUST_CFA_OFFSET -24
1472 jmp irq_return
1473 CFI_ENDPROC
1474END(nmi)
1475
1476ENTRY(int3)
1477 RING0_INT_FRAME
1478 pushl $-1 # mark this as an int
1479 CFI_ADJUST_CFA_OFFSET 4
1480 SAVE_ALL
1481 TRACE_IRQS_OFF
1482 xorl %edx,%edx # zero error code
1483 movl %esp,%eax # pt_regs pointer
1484 call do_int3
1485 jmp ret_from_exception
1486 CFI_ENDPROC
1487END(int3)
1488
1489ENTRY(general_protection)
1490 RING0_EC_FRAME
1491 pushl $do_general_protection
1492 CFI_ADJUST_CFA_OFFSET 4
1493 jmp error_code
1494 CFI_ENDPROC
1495END(general_protection)
1496
1497/*
1498 * End of kprobes section
1499 */
1500 .popsection
Linux 6.x block layer and io_uring tree(s)