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1/*
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 *
17 * Stack layout in 'syscall_exit':
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
32 * 24(%esp) - %fs
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
40 *
41 * "current" is in register %ebx during any slow entries.
42 */
43
44#include <linux/linkage.h>
45#include <linux/err.h>
46#include <asm/thread_info.h>
47#include <asm/irqflags.h>
48#include <asm/errno.h>
49#include <asm/segment.h>
50#include <asm/smp.h>
51#include <asm/page_types.h>
52#include <asm/percpu.h>
53#include <asm/dwarf2.h>
54#include <asm/processor-flags.h>
55#include <asm/ftrace.h>
56#include <asm/irq_vectors.h>
57#include <asm/cpufeature.h>
58#include <asm/alternative-asm.h>
59#include <asm/asm.h>
60
61/* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */
62#include <linux/elf-em.h>
63#define AUDIT_ARCH_I386 (EM_386|__AUDIT_ARCH_LE)
64#define __AUDIT_ARCH_LE 0x40000000
65
66#ifndef CONFIG_AUDITSYSCALL
67#define sysenter_audit syscall_trace_entry
68#define sysexit_audit syscall_exit_work
69#endif
70
71 .section .entry.text, "ax"
72
73/*
74 * We use macros for low-level operations which need to be overridden
75 * for paravirtualization. The following will never clobber any registers:
76 * INTERRUPT_RETURN (aka. "iret")
77 * GET_CR0_INTO_EAX (aka. "movl %cr0, %eax")
78 * ENABLE_INTERRUPTS_SYSEXIT (aka "sti; sysexit").
79 *
80 * For DISABLE_INTERRUPTS/ENABLE_INTERRUPTS (aka "cli"/"sti"), you must
81 * specify what registers can be overwritten (CLBR_NONE, CLBR_EAX/EDX/ECX/ANY).
82 * Allowing a register to be clobbered can shrink the paravirt replacement
83 * enough to patch inline, increasing performance.
84 */
85
86#ifdef CONFIG_PREEMPT
87#define preempt_stop(clobbers) DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF
88#else
89#define preempt_stop(clobbers)
90#define resume_kernel restore_all
91#endif
92
93.macro TRACE_IRQS_IRET
94#ifdef CONFIG_TRACE_IRQFLAGS
95 testl $X86_EFLAGS_IF,PT_EFLAGS(%esp) # interrupts off?
96 jz 1f
97 TRACE_IRQS_ON
981:
99#endif
100.endm
101
102/*
103 * User gs save/restore
104 *
105 * %gs is used for userland TLS and kernel only uses it for stack
106 * canary which is required to be at %gs:20 by gcc. Read the comment
107 * at the top of stackprotector.h for more info.
108 *
109 * Local labels 98 and 99 are used.
110 */
111#ifdef CONFIG_X86_32_LAZY_GS
112
113 /* unfortunately push/pop can't be no-op */
114.macro PUSH_GS
115 pushl_cfi $0
116.endm
117.macro POP_GS pop=0
118 addl $(4 + \pop), %esp
119 CFI_ADJUST_CFA_OFFSET -(4 + \pop)
120.endm
121.macro POP_GS_EX
122.endm
123
124 /* all the rest are no-op */
125.macro PTGS_TO_GS
126.endm
127.macro PTGS_TO_GS_EX
128.endm
129.macro GS_TO_REG reg
130.endm
131.macro REG_TO_PTGS reg
132.endm
133.macro SET_KERNEL_GS reg
134.endm
135
136#else /* CONFIG_X86_32_LAZY_GS */
137
138.macro PUSH_GS
139 pushl_cfi %gs
140 /*CFI_REL_OFFSET gs, 0*/
141.endm
142
143.macro POP_GS pop=0
14498: popl_cfi %gs
145 /*CFI_RESTORE gs*/
146 .if \pop <> 0
147 add $\pop, %esp
148 CFI_ADJUST_CFA_OFFSET -\pop
149 .endif
150.endm
151.macro POP_GS_EX
152.pushsection .fixup, "ax"
15399: movl $0, (%esp)
154 jmp 98b
155.popsection
156 _ASM_EXTABLE(98b,99b)
157.endm
158
159.macro PTGS_TO_GS
16098: mov PT_GS(%esp), %gs
161.endm
162.macro PTGS_TO_GS_EX
163.pushsection .fixup, "ax"
16499: movl $0, PT_GS(%esp)
165 jmp 98b
166.popsection
167 _ASM_EXTABLE(98b,99b)
168.endm
169
170.macro GS_TO_REG reg
171 movl %gs, \reg
172 /*CFI_REGISTER gs, \reg*/
173.endm
174.macro REG_TO_PTGS reg
175 movl \reg, PT_GS(%esp)
176 /*CFI_REL_OFFSET gs, PT_GS*/
177.endm
178.macro SET_KERNEL_GS reg
179 movl $(__KERNEL_STACK_CANARY), \reg
180 movl \reg, %gs
181.endm
182
183#endif /* CONFIG_X86_32_LAZY_GS */
184
185.macro SAVE_ALL
186 cld
187 PUSH_GS
188 pushl_cfi %fs
189 /*CFI_REL_OFFSET fs, 0;*/
190 pushl_cfi %es
191 /*CFI_REL_OFFSET es, 0;*/
192 pushl_cfi %ds
193 /*CFI_REL_OFFSET ds, 0;*/
194 pushl_cfi %eax
195 CFI_REL_OFFSET eax, 0
196 pushl_cfi %ebp
197 CFI_REL_OFFSET ebp, 0
198 pushl_cfi %edi
199 CFI_REL_OFFSET edi, 0
200 pushl_cfi %esi
201 CFI_REL_OFFSET esi, 0
202 pushl_cfi %edx
203 CFI_REL_OFFSET edx, 0
204 pushl_cfi %ecx
205 CFI_REL_OFFSET ecx, 0
206 pushl_cfi %ebx
207 CFI_REL_OFFSET ebx, 0
208 movl $(__USER_DS), %edx
209 movl %edx, %ds
210 movl %edx, %es
211 movl $(__KERNEL_PERCPU), %edx
212 movl %edx, %fs
213 SET_KERNEL_GS %edx
214.endm
215
216.macro RESTORE_INT_REGS
217 popl_cfi %ebx
218 CFI_RESTORE ebx
219 popl_cfi %ecx
220 CFI_RESTORE ecx
221 popl_cfi %edx
222 CFI_RESTORE edx
223 popl_cfi %esi
224 CFI_RESTORE esi
225 popl_cfi %edi
226 CFI_RESTORE edi
227 popl_cfi %ebp
228 CFI_RESTORE ebp
229 popl_cfi %eax
230 CFI_RESTORE eax
231.endm
232
233.macro RESTORE_REGS pop=0
234 RESTORE_INT_REGS
2351: popl_cfi %ds
236 /*CFI_RESTORE ds;*/
2372: popl_cfi %es
238 /*CFI_RESTORE es;*/
2393: popl_cfi %fs
240 /*CFI_RESTORE fs;*/
241 POP_GS \pop
242.pushsection .fixup, "ax"
2434: movl $0, (%esp)
244 jmp 1b
2455: movl $0, (%esp)
246 jmp 2b
2476: movl $0, (%esp)
248 jmp 3b
249.popsection
250 _ASM_EXTABLE(1b,4b)
251 _ASM_EXTABLE(2b,5b)
252 _ASM_EXTABLE(3b,6b)
253 POP_GS_EX
254.endm
255
256.macro RING0_INT_FRAME
257 CFI_STARTPROC simple
258 CFI_SIGNAL_FRAME
259 CFI_DEF_CFA esp, 3*4
260 /*CFI_OFFSET cs, -2*4;*/
261 CFI_OFFSET eip, -3*4
262.endm
263
264.macro RING0_EC_FRAME
265 CFI_STARTPROC simple
266 CFI_SIGNAL_FRAME
267 CFI_DEF_CFA esp, 4*4
268 /*CFI_OFFSET cs, -2*4;*/
269 CFI_OFFSET eip, -3*4
270.endm
271
272.macro RING0_PTREGS_FRAME
273 CFI_STARTPROC simple
274 CFI_SIGNAL_FRAME
275 CFI_DEF_CFA esp, PT_OLDESP-PT_EBX
276 /*CFI_OFFSET cs, PT_CS-PT_OLDESP;*/
277 CFI_OFFSET eip, PT_EIP-PT_OLDESP
278 /*CFI_OFFSET es, PT_ES-PT_OLDESP;*/
279 /*CFI_OFFSET ds, PT_DS-PT_OLDESP;*/
280 CFI_OFFSET eax, PT_EAX-PT_OLDESP
281 CFI_OFFSET ebp, PT_EBP-PT_OLDESP
282 CFI_OFFSET edi, PT_EDI-PT_OLDESP
283 CFI_OFFSET esi, PT_ESI-PT_OLDESP
284 CFI_OFFSET edx, PT_EDX-PT_OLDESP
285 CFI_OFFSET ecx, PT_ECX-PT_OLDESP
286 CFI_OFFSET ebx, PT_EBX-PT_OLDESP
287.endm
288
289ENTRY(ret_from_fork)
290 CFI_STARTPROC
291 pushl_cfi %eax
292 call schedule_tail
293 GET_THREAD_INFO(%ebp)
294 popl_cfi %eax
295 pushl_cfi $0x0202 # Reset kernel eflags
296 popfl_cfi
297 jmp syscall_exit
298 CFI_ENDPROC
299END(ret_from_fork)
300
301/*
302 * Interrupt exit functions should be protected against kprobes
303 */
304 .pushsection .kprobes.text, "ax"
305/*
306 * Return to user mode is not as complex as all this looks,
307 * but we want the default path for a system call return to
308 * go as quickly as possible which is why some of this is
309 * less clear than it otherwise should be.
310 */
311
312 # userspace resumption stub bypassing syscall exit tracing
313 ALIGN
314 RING0_PTREGS_FRAME
315ret_from_exception:
316 preempt_stop(CLBR_ANY)
317ret_from_intr:
318 GET_THREAD_INFO(%ebp)
319#ifdef CONFIG_VM86
320 movl PT_EFLAGS(%esp), %eax # mix EFLAGS and CS
321 movb PT_CS(%esp), %al
322 andl $(X86_EFLAGS_VM | SEGMENT_RPL_MASK), %eax
323#else
324 /*
325 * We can be coming here from a syscall done in the kernel space,
326 * e.g. a failed kernel_execve().
327 */
328 movl PT_CS(%esp), %eax
329 andl $SEGMENT_RPL_MASK, %eax
330#endif
331 cmpl $USER_RPL, %eax
332 jb resume_kernel # not returning to v8086 or userspace
333
334ENTRY(resume_userspace)
335 LOCKDEP_SYS_EXIT
336 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
337 # setting need_resched or sigpending
338 # between sampling and the iret
339 TRACE_IRQS_OFF
340 movl TI_flags(%ebp), %ecx
341 andl $_TIF_WORK_MASK, %ecx # is there any work to be done on
342 # int/exception return?
343 jne work_pending
344 jmp restore_all
345END(ret_from_exception)
346
347#ifdef CONFIG_PREEMPT
348ENTRY(resume_kernel)
349 DISABLE_INTERRUPTS(CLBR_ANY)
350 cmpl $0,TI_preempt_count(%ebp) # non-zero preempt_count ?
351 jnz restore_all
352need_resched:
353 movl TI_flags(%ebp), %ecx # need_resched set ?
354 testb $_TIF_NEED_RESCHED, %cl
355 jz restore_all
356 testl $X86_EFLAGS_IF,PT_EFLAGS(%esp) # interrupts off (exception path) ?
357 jz restore_all
358 call preempt_schedule_irq
359 jmp need_resched
360END(resume_kernel)
361#endif
362 CFI_ENDPROC
363/*
364 * End of kprobes section
365 */
366 .popsection
367
368/* SYSENTER_RETURN points to after the "sysenter" instruction in
369 the vsyscall page. See vsyscall-sysentry.S, which defines the symbol. */
370
371 # sysenter call handler stub
372ENTRY(ia32_sysenter_target)
373 CFI_STARTPROC simple
374 CFI_SIGNAL_FRAME
375 CFI_DEF_CFA esp, 0
376 CFI_REGISTER esp, ebp
377 movl TSS_sysenter_sp0(%esp),%esp
378sysenter_past_esp:
379 /*
380 * Interrupts are disabled here, but we can't trace it until
381 * enough kernel state to call TRACE_IRQS_OFF can be called - but
382 * we immediately enable interrupts at that point anyway.
383 */
384 pushl_cfi $__USER_DS
385 /*CFI_REL_OFFSET ss, 0*/
386 pushl_cfi %ebp
387 CFI_REL_OFFSET esp, 0
388 pushfl_cfi
389 orl $X86_EFLAGS_IF, (%esp)
390 pushl_cfi $__USER_CS
391 /*CFI_REL_OFFSET cs, 0*/
392 /*
393 * Push current_thread_info()->sysenter_return to the stack.
394 * A tiny bit of offset fixup is necessary - 4*4 means the 4 words
395 * pushed above; +8 corresponds to copy_thread's esp0 setting.
396 */
397 pushl_cfi ((TI_sysenter_return)-THREAD_SIZE+8+4*4)(%esp)
398 CFI_REL_OFFSET eip, 0
399
400 pushl_cfi %eax
401 SAVE_ALL
402 ENABLE_INTERRUPTS(CLBR_NONE)
403
404/*
405 * Load the potential sixth argument from user stack.
406 * Careful about security.
407 */
408 cmpl $__PAGE_OFFSET-3,%ebp
409 jae syscall_fault
4101: movl (%ebp),%ebp
411 movl %ebp,PT_EBP(%esp)
412 _ASM_EXTABLE(1b,syscall_fault)
413
414 GET_THREAD_INFO(%ebp)
415
416 testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%ebp)
417 jnz sysenter_audit
418sysenter_do_call:
419 cmpl $(NR_syscalls), %eax
420 jae syscall_badsys
421 call *sys_call_table(,%eax,4)
422 movl %eax,PT_EAX(%esp)
423 LOCKDEP_SYS_EXIT
424 DISABLE_INTERRUPTS(CLBR_ANY)
425 TRACE_IRQS_OFF
426 movl TI_flags(%ebp), %ecx
427 testl $_TIF_ALLWORK_MASK, %ecx
428 jne sysexit_audit
429sysenter_exit:
430/* if something modifies registers it must also disable sysexit */
431 movl PT_EIP(%esp), %edx
432 movl PT_OLDESP(%esp), %ecx
433 xorl %ebp,%ebp
434 TRACE_IRQS_ON
4351: mov PT_FS(%esp), %fs
436 PTGS_TO_GS
437 ENABLE_INTERRUPTS_SYSEXIT
438
439#ifdef CONFIG_AUDITSYSCALL
440sysenter_audit:
441 testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
442 jnz syscall_trace_entry
443 addl $4,%esp
444 CFI_ADJUST_CFA_OFFSET -4
445 /* %esi already in 8(%esp) 6th arg: 4th syscall arg */
446 /* %edx already in 4(%esp) 5th arg: 3rd syscall arg */
447 /* %ecx already in 0(%esp) 4th arg: 2nd syscall arg */
448 movl %ebx,%ecx /* 3rd arg: 1st syscall arg */
449 movl %eax,%edx /* 2nd arg: syscall number */
450 movl $AUDIT_ARCH_I386,%eax /* 1st arg: audit arch */
451 call __audit_syscall_entry
452 pushl_cfi %ebx
453 movl PT_EAX(%esp),%eax /* reload syscall number */
454 jmp sysenter_do_call
455
456sysexit_audit:
457 testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %ecx
458 jne syscall_exit_work
459 TRACE_IRQS_ON
460 ENABLE_INTERRUPTS(CLBR_ANY)
461 movl %eax,%edx /* second arg, syscall return value */
462 cmpl $-MAX_ERRNO,%eax /* is it an error ? */
463 setbe %al /* 1 if so, 0 if not */
464 movzbl %al,%eax /* zero-extend that */
465 call __audit_syscall_exit
466 DISABLE_INTERRUPTS(CLBR_ANY)
467 TRACE_IRQS_OFF
468 movl TI_flags(%ebp), %ecx
469 testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %ecx
470 jne syscall_exit_work
471 movl PT_EAX(%esp),%eax /* reload syscall return value */
472 jmp sysenter_exit
473#endif
474
475 CFI_ENDPROC
476.pushsection .fixup,"ax"
4772: movl $0,PT_FS(%esp)
478 jmp 1b
479.popsection
480 _ASM_EXTABLE(1b,2b)
481 PTGS_TO_GS_EX
482ENDPROC(ia32_sysenter_target)
483
484/*
485 * syscall stub including irq exit should be protected against kprobes
486 */
487 .pushsection .kprobes.text, "ax"
488 # system call handler stub
489ENTRY(system_call)
490 RING0_INT_FRAME # can't unwind into user space anyway
491 pushl_cfi %eax # save orig_eax
492 SAVE_ALL
493 GET_THREAD_INFO(%ebp)
494 # system call tracing in operation / emulation
495 testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%ebp)
496 jnz syscall_trace_entry
497 cmpl $(NR_syscalls), %eax
498 jae syscall_badsys
499syscall_call:
500 call *sys_call_table(,%eax,4)
501 movl %eax,PT_EAX(%esp) # store the return value
502syscall_exit:
503 LOCKDEP_SYS_EXIT
504 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
505 # setting need_resched or sigpending
506 # between sampling and the iret
507 TRACE_IRQS_OFF
508 movl TI_flags(%ebp), %ecx
509 testl $_TIF_ALLWORK_MASK, %ecx # current->work
510 jne syscall_exit_work
511
512restore_all:
513 TRACE_IRQS_IRET
514restore_all_notrace:
515 movl PT_EFLAGS(%esp), %eax # mix EFLAGS, SS and CS
516 # Warning: PT_OLDSS(%esp) contains the wrong/random values if we
517 # are returning to the kernel.
518 # See comments in process.c:copy_thread() for details.
519 movb PT_OLDSS(%esp), %ah
520 movb PT_CS(%esp), %al
521 andl $(X86_EFLAGS_VM | (SEGMENT_TI_MASK << 8) | SEGMENT_RPL_MASK), %eax
522 cmpl $((SEGMENT_LDT << 8) | USER_RPL), %eax
523 CFI_REMEMBER_STATE
524 je ldt_ss # returning to user-space with LDT SS
525restore_nocheck:
526 RESTORE_REGS 4 # skip orig_eax/error_code
527irq_return:
528 INTERRUPT_RETURN
529.section .fixup,"ax"
530ENTRY(iret_exc)
531 pushl $0 # no error code
532 pushl $do_iret_error
533 jmp error_code
534.previous
535 _ASM_EXTABLE(irq_return,iret_exc)
536
537 CFI_RESTORE_STATE
538ldt_ss:
539 larl PT_OLDSS(%esp), %eax
540 jnz restore_nocheck
541 testl $0x00400000, %eax # returning to 32bit stack?
542 jnz restore_nocheck # allright, normal return
543
544#ifdef CONFIG_PARAVIRT
545 /*
546 * The kernel can't run on a non-flat stack if paravirt mode
547 * is active. Rather than try to fixup the high bits of
548 * ESP, bypass this code entirely. This may break DOSemu
549 * and/or Wine support in a paravirt VM, although the option
550 * is still available to implement the setting of the high
551 * 16-bits in the INTERRUPT_RETURN paravirt-op.
552 */
553 cmpl $0, pv_info+PARAVIRT_enabled
554 jne restore_nocheck
555#endif
556
557/*
558 * Setup and switch to ESPFIX stack
559 *
560 * We're returning to userspace with a 16 bit stack. The CPU will not
561 * restore the high word of ESP for us on executing iret... This is an
562 * "official" bug of all the x86-compatible CPUs, which we can work
563 * around to make dosemu and wine happy. We do this by preloading the
564 * high word of ESP with the high word of the userspace ESP while
565 * compensating for the offset by changing to the ESPFIX segment with
566 * a base address that matches for the difference.
567 */
568#define GDT_ESPFIX_SS PER_CPU_VAR(gdt_page) + (GDT_ENTRY_ESPFIX_SS * 8)
569 mov %esp, %edx /* load kernel esp */
570 mov PT_OLDESP(%esp), %eax /* load userspace esp */
571 mov %dx, %ax /* eax: new kernel esp */
572 sub %eax, %edx /* offset (low word is 0) */
573 shr $16, %edx
574 mov %dl, GDT_ESPFIX_SS + 4 /* bits 16..23 */
575 mov %dh, GDT_ESPFIX_SS + 7 /* bits 24..31 */
576 pushl_cfi $__ESPFIX_SS
577 pushl_cfi %eax /* new kernel esp */
578 /* Disable interrupts, but do not irqtrace this section: we
579 * will soon execute iret and the tracer was already set to
580 * the irqstate after the iret */
581 DISABLE_INTERRUPTS(CLBR_EAX)
582 lss (%esp), %esp /* switch to espfix segment */
583 CFI_ADJUST_CFA_OFFSET -8
584 jmp restore_nocheck
585 CFI_ENDPROC
586ENDPROC(system_call)
587
588 # perform work that needs to be done immediately before resumption
589 ALIGN
590 RING0_PTREGS_FRAME # can't unwind into user space anyway
591work_pending:
592 testb $_TIF_NEED_RESCHED, %cl
593 jz work_notifysig
594work_resched:
595 call schedule
596 LOCKDEP_SYS_EXIT
597 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
598 # setting need_resched or sigpending
599 # between sampling and the iret
600 TRACE_IRQS_OFF
601 movl TI_flags(%ebp), %ecx
602 andl $_TIF_WORK_MASK, %ecx # is there any work to be done other
603 # than syscall tracing?
604 jz restore_all
605 testb $_TIF_NEED_RESCHED, %cl
606 jnz work_resched
607
608work_notifysig: # deal with pending signals and
609 # notify-resume requests
610#ifdef CONFIG_VM86
611 testl $X86_EFLAGS_VM, PT_EFLAGS(%esp)
612 movl %esp, %eax
613 jne work_notifysig_v86 # returning to kernel-space or
614 # vm86-space
615 TRACE_IRQS_ON
616 ENABLE_INTERRUPTS(CLBR_NONE)
617 movb PT_CS(%esp), %bl
618 andb $SEGMENT_RPL_MASK, %bl
619 cmpb $USER_RPL, %bl
620 jb resume_kernel
621 xorl %edx, %edx
622 call do_notify_resume
623 jmp resume_userspace
624
625 ALIGN
626work_notifysig_v86:
627 pushl_cfi %ecx # save ti_flags for do_notify_resume
628 call save_v86_state # %eax contains pt_regs pointer
629 popl_cfi %ecx
630 movl %eax, %esp
631#else
632 movl %esp, %eax
633#endif
634 TRACE_IRQS_ON
635 ENABLE_INTERRUPTS(CLBR_NONE)
636 movb PT_CS(%esp), %bl
637 andb $SEGMENT_RPL_MASK, %bl
638 cmpb $USER_RPL, %bl
639 jb resume_kernel
640 xorl %edx, %edx
641 call do_notify_resume
642 jmp resume_userspace
643END(work_pending)
644
645 # perform syscall exit tracing
646 ALIGN
647syscall_trace_entry:
648 movl $-ENOSYS,PT_EAX(%esp)
649 movl %esp, %eax
650 call syscall_trace_enter
651 /* What it returned is what we'll actually use. */
652 cmpl $(NR_syscalls), %eax
653 jnae syscall_call
654 jmp syscall_exit
655END(syscall_trace_entry)
656
657 # perform syscall exit tracing
658 ALIGN
659syscall_exit_work:
660 testl $_TIF_WORK_SYSCALL_EXIT, %ecx
661 jz work_pending
662 TRACE_IRQS_ON
663 ENABLE_INTERRUPTS(CLBR_ANY) # could let syscall_trace_leave() call
664 # schedule() instead
665 movl %esp, %eax
666 call syscall_trace_leave
667 jmp resume_userspace
668END(syscall_exit_work)
669 CFI_ENDPROC
670
671 RING0_INT_FRAME # can't unwind into user space anyway
672syscall_fault:
673 GET_THREAD_INFO(%ebp)
674 movl $-EFAULT,PT_EAX(%esp)
675 jmp resume_userspace
676END(syscall_fault)
677
678syscall_badsys:
679 movl $-ENOSYS,PT_EAX(%esp)
680 jmp resume_userspace
681END(syscall_badsys)
682 CFI_ENDPROC
683/*
684 * End of kprobes section
685 */
686 .popsection
687
688/*
689 * System calls that need a pt_regs pointer.
690 */
691#define PTREGSCALL0(name) \
692ENTRY(ptregs_##name) ; \
693 leal 4(%esp),%eax; \
694 jmp sys_##name; \
695ENDPROC(ptregs_##name)
696
697#define PTREGSCALL1(name) \
698ENTRY(ptregs_##name) ; \
699 leal 4(%esp),%edx; \
700 movl (PT_EBX+4)(%esp),%eax; \
701 jmp sys_##name; \
702ENDPROC(ptregs_##name)
703
704#define PTREGSCALL2(name) \
705ENTRY(ptregs_##name) ; \
706 leal 4(%esp),%ecx; \
707 movl (PT_ECX+4)(%esp),%edx; \
708 movl (PT_EBX+4)(%esp),%eax; \
709 jmp sys_##name; \
710ENDPROC(ptregs_##name)
711
712#define PTREGSCALL3(name) \
713ENTRY(ptregs_##name) ; \
714 CFI_STARTPROC; \
715 leal 4(%esp),%eax; \
716 pushl_cfi %eax; \
717 movl PT_EDX(%eax),%ecx; \
718 movl PT_ECX(%eax),%edx; \
719 movl PT_EBX(%eax),%eax; \
720 call sys_##name; \
721 addl $4,%esp; \
722 CFI_ADJUST_CFA_OFFSET -4; \
723 ret; \
724 CFI_ENDPROC; \
725ENDPROC(ptregs_##name)
726
727PTREGSCALL1(iopl)
728PTREGSCALL0(fork)
729PTREGSCALL0(vfork)
730PTREGSCALL3(execve)
731PTREGSCALL2(sigaltstack)
732PTREGSCALL0(sigreturn)
733PTREGSCALL0(rt_sigreturn)
734PTREGSCALL2(vm86)
735PTREGSCALL1(vm86old)
736
737/* Clone is an oddball. The 4th arg is in %edi */
738ENTRY(ptregs_clone)
739 CFI_STARTPROC
740 leal 4(%esp),%eax
741 pushl_cfi %eax
742 pushl_cfi PT_EDI(%eax)
743 movl PT_EDX(%eax),%ecx
744 movl PT_ECX(%eax),%edx
745 movl PT_EBX(%eax),%eax
746 call sys_clone
747 addl $8,%esp
748 CFI_ADJUST_CFA_OFFSET -8
749 ret
750 CFI_ENDPROC
751ENDPROC(ptregs_clone)
752
753.macro FIXUP_ESPFIX_STACK
754/*
755 * Switch back for ESPFIX stack to the normal zerobased stack
756 *
757 * We can't call C functions using the ESPFIX stack. This code reads
758 * the high word of the segment base from the GDT and swiches to the
759 * normal stack and adjusts ESP with the matching offset.
760 */
761 /* fixup the stack */
762 mov GDT_ESPFIX_SS + 4, %al /* bits 16..23 */
763 mov GDT_ESPFIX_SS + 7, %ah /* bits 24..31 */
764 shl $16, %eax
765 addl %esp, %eax /* the adjusted stack pointer */
766 pushl_cfi $__KERNEL_DS
767 pushl_cfi %eax
768 lss (%esp), %esp /* switch to the normal stack segment */
769 CFI_ADJUST_CFA_OFFSET -8
770.endm
771.macro UNWIND_ESPFIX_STACK
772 movl %ss, %eax
773 /* see if on espfix stack */
774 cmpw $__ESPFIX_SS, %ax
775 jne 27f
776 movl $__KERNEL_DS, %eax
777 movl %eax, %ds
778 movl %eax, %es
779 /* switch to normal stack */
780 FIXUP_ESPFIX_STACK
78127:
782.endm
783
784/*
785 * Build the entry stubs and pointer table with some assembler magic.
786 * We pack 7 stubs into a single 32-byte chunk, which will fit in a
787 * single cache line on all modern x86 implementations.
788 */
789.section .init.rodata,"a"
790ENTRY(interrupt)
791.section .entry.text, "ax"
792 .p2align 5
793 .p2align CONFIG_X86_L1_CACHE_SHIFT
794ENTRY(irq_entries_start)
795 RING0_INT_FRAME
796vector=FIRST_EXTERNAL_VECTOR
797.rept (NR_VECTORS-FIRST_EXTERNAL_VECTOR+6)/7
798 .balign 32
799 .rept 7
800 .if vector < NR_VECTORS
801 .if vector <> FIRST_EXTERNAL_VECTOR
802 CFI_ADJUST_CFA_OFFSET -4
803 .endif
8041: pushl_cfi $(~vector+0x80) /* Note: always in signed byte range */
805 .if ((vector-FIRST_EXTERNAL_VECTOR)%7) <> 6
806 jmp 2f
807 .endif
808 .previous
809 .long 1b
810 .section .entry.text, "ax"
811vector=vector+1
812 .endif
813 .endr
8142: jmp common_interrupt
815.endr
816END(irq_entries_start)
817
818.previous
819END(interrupt)
820.previous
821
822/*
823 * the CPU automatically disables interrupts when executing an IRQ vector,
824 * so IRQ-flags tracing has to follow that:
825 */
826 .p2align CONFIG_X86_L1_CACHE_SHIFT
827common_interrupt:
828 addl $-0x80,(%esp) /* Adjust vector into the [-256,-1] range */
829 SAVE_ALL
830 TRACE_IRQS_OFF
831 movl %esp,%eax
832 call do_IRQ
833 jmp ret_from_intr
834ENDPROC(common_interrupt)
835 CFI_ENDPROC
836
837/*
838 * Irq entries should be protected against kprobes
839 */
840 .pushsection .kprobes.text, "ax"
841#define BUILD_INTERRUPT3(name, nr, fn) \
842ENTRY(name) \
843 RING0_INT_FRAME; \
844 pushl_cfi $~(nr); \
845 SAVE_ALL; \
846 TRACE_IRQS_OFF \
847 movl %esp,%eax; \
848 call fn; \
849 jmp ret_from_intr; \
850 CFI_ENDPROC; \
851ENDPROC(name)
852
853#define BUILD_INTERRUPT(name, nr) BUILD_INTERRUPT3(name, nr, smp_##name)
854
855/* The include is where all of the SMP etc. interrupts come from */
856#include <asm/entry_arch.h>
857
858ENTRY(coprocessor_error)
859 RING0_INT_FRAME
860 pushl_cfi $0
861 pushl_cfi $do_coprocessor_error
862 jmp error_code
863 CFI_ENDPROC
864END(coprocessor_error)
865
866ENTRY(simd_coprocessor_error)
867 RING0_INT_FRAME
868 pushl_cfi $0
869#ifdef CONFIG_X86_INVD_BUG
870 /* AMD 486 bug: invd from userspace calls exception 19 instead of #GP */
871661: pushl_cfi $do_general_protection
872662:
873.section .altinstructions,"a"
874 altinstruction_entry 661b, 663f, X86_FEATURE_XMM, 662b-661b, 664f-663f
875.previous
876.section .altinstr_replacement,"ax"
877663: pushl $do_simd_coprocessor_error
878664:
879.previous
880#else
881 pushl_cfi $do_simd_coprocessor_error
882#endif
883 jmp error_code
884 CFI_ENDPROC
885END(simd_coprocessor_error)
886
887ENTRY(device_not_available)
888 RING0_INT_FRAME
889 pushl_cfi $-1 # mark this as an int
890 pushl_cfi $do_device_not_available
891 jmp error_code
892 CFI_ENDPROC
893END(device_not_available)
894
895#ifdef CONFIG_PARAVIRT
896ENTRY(native_iret)
897 iret
898 _ASM_EXTABLE(native_iret, iret_exc)
899END(native_iret)
900
901ENTRY(native_irq_enable_sysexit)
902 sti
903 sysexit
904END(native_irq_enable_sysexit)
905#endif
906
907ENTRY(overflow)
908 RING0_INT_FRAME
909 pushl_cfi $0
910 pushl_cfi $do_overflow
911 jmp error_code
912 CFI_ENDPROC
913END(overflow)
914
915ENTRY(bounds)
916 RING0_INT_FRAME
917 pushl_cfi $0
918 pushl_cfi $do_bounds
919 jmp error_code
920 CFI_ENDPROC
921END(bounds)
922
923ENTRY(invalid_op)
924 RING0_INT_FRAME
925 pushl_cfi $0
926 pushl_cfi $do_invalid_op
927 jmp error_code
928 CFI_ENDPROC
929END(invalid_op)
930
931ENTRY(coprocessor_segment_overrun)
932 RING0_INT_FRAME
933 pushl_cfi $0
934 pushl_cfi $do_coprocessor_segment_overrun
935 jmp error_code
936 CFI_ENDPROC
937END(coprocessor_segment_overrun)
938
939ENTRY(invalid_TSS)
940 RING0_EC_FRAME
941 pushl_cfi $do_invalid_TSS
942 jmp error_code
943 CFI_ENDPROC
944END(invalid_TSS)
945
946ENTRY(segment_not_present)
947 RING0_EC_FRAME
948 pushl_cfi $do_segment_not_present
949 jmp error_code
950 CFI_ENDPROC
951END(segment_not_present)
952
953ENTRY(stack_segment)
954 RING0_EC_FRAME
955 pushl_cfi $do_stack_segment
956 jmp error_code
957 CFI_ENDPROC
958END(stack_segment)
959
960ENTRY(alignment_check)
961 RING0_EC_FRAME
962 pushl_cfi $do_alignment_check
963 jmp error_code
964 CFI_ENDPROC
965END(alignment_check)
966
967ENTRY(divide_error)
968 RING0_INT_FRAME
969 pushl_cfi $0 # no error code
970 pushl_cfi $do_divide_error
971 jmp error_code
972 CFI_ENDPROC
973END(divide_error)
974
975#ifdef CONFIG_X86_MCE
976ENTRY(machine_check)
977 RING0_INT_FRAME
978 pushl_cfi $0
979 pushl_cfi machine_check_vector
980 jmp error_code
981 CFI_ENDPROC
982END(machine_check)
983#endif
984
985ENTRY(spurious_interrupt_bug)
986 RING0_INT_FRAME
987 pushl_cfi $0
988 pushl_cfi $do_spurious_interrupt_bug
989 jmp error_code
990 CFI_ENDPROC
991END(spurious_interrupt_bug)
992/*
993 * End of kprobes section
994 */
995 .popsection
996
997ENTRY(kernel_thread_helper)
998 pushl $0 # fake return address for unwinder
999 CFI_STARTPROC
1000 movl %edi,%eax
1001 call *%esi
1002 call do_exit
1003 ud2 # padding for call trace
1004 CFI_ENDPROC
1005ENDPROC(kernel_thread_helper)
1006
1007#ifdef CONFIG_XEN
1008/* Xen doesn't set %esp to be precisely what the normal sysenter
1009 entrypoint expects, so fix it up before using the normal path. */
1010ENTRY(xen_sysenter_target)
1011 RING0_INT_FRAME
1012 addl $5*4, %esp /* remove xen-provided frame */
1013 CFI_ADJUST_CFA_OFFSET -5*4
1014 jmp sysenter_past_esp
1015 CFI_ENDPROC
1016
1017ENTRY(xen_hypervisor_callback)
1018 CFI_STARTPROC
1019 pushl_cfi $0
1020 SAVE_ALL
1021 TRACE_IRQS_OFF
1022
1023 /* Check to see if we got the event in the critical
1024 region in xen_iret_direct, after we've reenabled
1025 events and checked for pending events. This simulates
1026 iret instruction's behaviour where it delivers a
1027 pending interrupt when enabling interrupts. */
1028 movl PT_EIP(%esp),%eax
1029 cmpl $xen_iret_start_crit,%eax
1030 jb 1f
1031 cmpl $xen_iret_end_crit,%eax
1032 jae 1f
1033
1034 jmp xen_iret_crit_fixup
1035
1036ENTRY(xen_do_upcall)
10371: mov %esp, %eax
1038 call xen_evtchn_do_upcall
1039 jmp ret_from_intr
1040 CFI_ENDPROC
1041ENDPROC(xen_hypervisor_callback)
1042
1043# Hypervisor uses this for application faults while it executes.
1044# We get here for two reasons:
1045# 1. Fault while reloading DS, ES, FS or GS
1046# 2. Fault while executing IRET
1047# Category 1 we fix up by reattempting the load, and zeroing the segment
1048# register if the load fails.
1049# Category 2 we fix up by jumping to do_iret_error. We cannot use the
1050# normal Linux return path in this case because if we use the IRET hypercall
1051# to pop the stack frame we end up in an infinite loop of failsafe callbacks.
1052# We distinguish between categories by maintaining a status value in EAX.
1053ENTRY(xen_failsafe_callback)
1054 CFI_STARTPROC
1055 pushl_cfi %eax
1056 movl $1,%eax
10571: mov 4(%esp),%ds
10582: mov 8(%esp),%es
10593: mov 12(%esp),%fs
10604: mov 16(%esp),%gs
1061 testl %eax,%eax
1062 popl_cfi %eax
1063 lea 16(%esp),%esp
1064 CFI_ADJUST_CFA_OFFSET -16
1065 jz 5f
1066 addl $16,%esp
1067 jmp iret_exc # EAX != 0 => Category 2 (Bad IRET)
10685: pushl_cfi $0 # EAX == 0 => Category 1 (Bad segment)
1069 SAVE_ALL
1070 jmp ret_from_exception
1071 CFI_ENDPROC
1072
1073.section .fixup,"ax"
10746: xorl %eax,%eax
1075 movl %eax,4(%esp)
1076 jmp 1b
10777: xorl %eax,%eax
1078 movl %eax,8(%esp)
1079 jmp 2b
10808: xorl %eax,%eax
1081 movl %eax,12(%esp)
1082 jmp 3b
10839: xorl %eax,%eax
1084 movl %eax,16(%esp)
1085 jmp 4b
1086.previous
1087 _ASM_EXTABLE(1b,6b)
1088 _ASM_EXTABLE(2b,7b)
1089 _ASM_EXTABLE(3b,8b)
1090 _ASM_EXTABLE(4b,9b)
1091ENDPROC(xen_failsafe_callback)
1092
1093BUILD_INTERRUPT3(xen_hvm_callback_vector, XEN_HVM_EVTCHN_CALLBACK,
1094 xen_evtchn_do_upcall)
1095
1096#endif /* CONFIG_XEN */
1097
1098#ifdef CONFIG_FUNCTION_TRACER
1099#ifdef CONFIG_DYNAMIC_FTRACE
1100
1101ENTRY(mcount)
1102 ret
1103END(mcount)
1104
1105ENTRY(ftrace_caller)
1106 cmpl $0, function_trace_stop
1107 jne ftrace_stub
1108
1109 pushl %eax
1110 pushl %ecx
1111 pushl %edx
1112 movl 0xc(%esp), %eax
1113 movl 0x4(%ebp), %edx
1114 subl $MCOUNT_INSN_SIZE, %eax
1115
1116.globl ftrace_call
1117ftrace_call:
1118 call ftrace_stub
1119
1120 popl %edx
1121 popl %ecx
1122 popl %eax
1123#ifdef CONFIG_FUNCTION_GRAPH_TRACER
1124.globl ftrace_graph_call
1125ftrace_graph_call:
1126 jmp ftrace_stub
1127#endif
1128
1129.globl ftrace_stub
1130ftrace_stub:
1131 ret
1132END(ftrace_caller)
1133
1134#else /* ! CONFIG_DYNAMIC_FTRACE */
1135
1136ENTRY(mcount)
1137 cmpl $0, function_trace_stop
1138 jne ftrace_stub
1139
1140 cmpl $ftrace_stub, ftrace_trace_function
1141 jnz trace
1142#ifdef CONFIG_FUNCTION_GRAPH_TRACER
1143 cmpl $ftrace_stub, ftrace_graph_return
1144 jnz ftrace_graph_caller
1145
1146 cmpl $ftrace_graph_entry_stub, ftrace_graph_entry
1147 jnz ftrace_graph_caller
1148#endif
1149.globl ftrace_stub
1150ftrace_stub:
1151 ret
1152
1153 /* taken from glibc */
1154trace:
1155 pushl %eax
1156 pushl %ecx
1157 pushl %edx
1158 movl 0xc(%esp), %eax
1159 movl 0x4(%ebp), %edx
1160 subl $MCOUNT_INSN_SIZE, %eax
1161
1162 call *ftrace_trace_function
1163
1164 popl %edx
1165 popl %ecx
1166 popl %eax
1167 jmp ftrace_stub
1168END(mcount)
1169#endif /* CONFIG_DYNAMIC_FTRACE */
1170#endif /* CONFIG_FUNCTION_TRACER */
1171
1172#ifdef CONFIG_FUNCTION_GRAPH_TRACER
1173ENTRY(ftrace_graph_caller)
1174 cmpl $0, function_trace_stop
1175 jne ftrace_stub
1176
1177 pushl %eax
1178 pushl %ecx
1179 pushl %edx
1180 movl 0xc(%esp), %edx
1181 lea 0x4(%ebp), %eax
1182 movl (%ebp), %ecx
1183 subl $MCOUNT_INSN_SIZE, %edx
1184 call prepare_ftrace_return
1185 popl %edx
1186 popl %ecx
1187 popl %eax
1188 ret
1189END(ftrace_graph_caller)
1190
1191.globl return_to_handler
1192return_to_handler:
1193 pushl %eax
1194 pushl %edx
1195 movl %ebp, %eax
1196 call ftrace_return_to_handler
1197 movl %eax, %ecx
1198 popl %edx
1199 popl %eax
1200 jmp *%ecx
1201#endif
1202
1203/*
1204 * Some functions should be protected against kprobes
1205 */
1206 .pushsection .kprobes.text, "ax"
1207
1208ENTRY(page_fault)
1209 RING0_EC_FRAME
1210 pushl_cfi $do_page_fault
1211 ALIGN
1212error_code:
1213 /* the function address is in %gs's slot on the stack */
1214 pushl_cfi %fs
1215 /*CFI_REL_OFFSET fs, 0*/
1216 pushl_cfi %es
1217 /*CFI_REL_OFFSET es, 0*/
1218 pushl_cfi %ds
1219 /*CFI_REL_OFFSET ds, 0*/
1220 pushl_cfi %eax
1221 CFI_REL_OFFSET eax, 0
1222 pushl_cfi %ebp
1223 CFI_REL_OFFSET ebp, 0
1224 pushl_cfi %edi
1225 CFI_REL_OFFSET edi, 0
1226 pushl_cfi %esi
1227 CFI_REL_OFFSET esi, 0
1228 pushl_cfi %edx
1229 CFI_REL_OFFSET edx, 0
1230 pushl_cfi %ecx
1231 CFI_REL_OFFSET ecx, 0
1232 pushl_cfi %ebx
1233 CFI_REL_OFFSET ebx, 0
1234 cld
1235 movl $(__KERNEL_PERCPU), %ecx
1236 movl %ecx, %fs
1237 UNWIND_ESPFIX_STACK
1238 GS_TO_REG %ecx
1239 movl PT_GS(%esp), %edi # get the function address
1240 movl PT_ORIG_EAX(%esp), %edx # get the error code
1241 movl $-1, PT_ORIG_EAX(%esp) # no syscall to restart
1242 REG_TO_PTGS %ecx
1243 SET_KERNEL_GS %ecx
1244 movl $(__USER_DS), %ecx
1245 movl %ecx, %ds
1246 movl %ecx, %es
1247 TRACE_IRQS_OFF
1248 movl %esp,%eax # pt_regs pointer
1249 call *%edi
1250 jmp ret_from_exception
1251 CFI_ENDPROC
1252END(page_fault)
1253
1254/*
1255 * Debug traps and NMI can happen at the one SYSENTER instruction
1256 * that sets up the real kernel stack. Check here, since we can't
1257 * allow the wrong stack to be used.
1258 *
1259 * "TSS_sysenter_sp0+12" is because the NMI/debug handler will have
1260 * already pushed 3 words if it hits on the sysenter instruction:
1261 * eflags, cs and eip.
1262 *
1263 * We just load the right stack, and push the three (known) values
1264 * by hand onto the new stack - while updating the return eip past
1265 * the instruction that would have done it for sysenter.
1266 */
1267.macro FIX_STACK offset ok label
1268 cmpw $__KERNEL_CS, 4(%esp)
1269 jne \ok
1270\label:
1271 movl TSS_sysenter_sp0 + \offset(%esp), %esp
1272 CFI_DEF_CFA esp, 0
1273 CFI_UNDEFINED eip
1274 pushfl_cfi
1275 pushl_cfi $__KERNEL_CS
1276 pushl_cfi $sysenter_past_esp
1277 CFI_REL_OFFSET eip, 0
1278.endm
1279
1280ENTRY(debug)
1281 RING0_INT_FRAME
1282 cmpl $ia32_sysenter_target,(%esp)
1283 jne debug_stack_correct
1284 FIX_STACK 12, debug_stack_correct, debug_esp_fix_insn
1285debug_stack_correct:
1286 pushl_cfi $-1 # mark this as an int
1287 SAVE_ALL
1288 TRACE_IRQS_OFF
1289 xorl %edx,%edx # error code 0
1290 movl %esp,%eax # pt_regs pointer
1291 call do_debug
1292 jmp ret_from_exception
1293 CFI_ENDPROC
1294END(debug)
1295
1296/*
1297 * NMI is doubly nasty. It can happen _while_ we're handling
1298 * a debug fault, and the debug fault hasn't yet been able to
1299 * clear up the stack. So we first check whether we got an
1300 * NMI on the sysenter entry path, but after that we need to
1301 * check whether we got an NMI on the debug path where the debug
1302 * fault happened on the sysenter path.
1303 */
1304ENTRY(nmi)
1305 RING0_INT_FRAME
1306 pushl_cfi %eax
1307 movl %ss, %eax
1308 cmpw $__ESPFIX_SS, %ax
1309 popl_cfi %eax
1310 je nmi_espfix_stack
1311 cmpl $ia32_sysenter_target,(%esp)
1312 je nmi_stack_fixup
1313 pushl_cfi %eax
1314 movl %esp,%eax
1315 /* Do not access memory above the end of our stack page,
1316 * it might not exist.
1317 */
1318 andl $(THREAD_SIZE-1),%eax
1319 cmpl $(THREAD_SIZE-20),%eax
1320 popl_cfi %eax
1321 jae nmi_stack_correct
1322 cmpl $ia32_sysenter_target,12(%esp)
1323 je nmi_debug_stack_check
1324nmi_stack_correct:
1325 /* We have a RING0_INT_FRAME here */
1326 pushl_cfi %eax
1327 SAVE_ALL
1328 xorl %edx,%edx # zero error code
1329 movl %esp,%eax # pt_regs pointer
1330 call do_nmi
1331 jmp restore_all_notrace
1332 CFI_ENDPROC
1333
1334nmi_stack_fixup:
1335 RING0_INT_FRAME
1336 FIX_STACK 12, nmi_stack_correct, 1
1337 jmp nmi_stack_correct
1338
1339nmi_debug_stack_check:
1340 /* We have a RING0_INT_FRAME here */
1341 cmpw $__KERNEL_CS,16(%esp)
1342 jne nmi_stack_correct
1343 cmpl $debug,(%esp)
1344 jb nmi_stack_correct
1345 cmpl $debug_esp_fix_insn,(%esp)
1346 ja nmi_stack_correct
1347 FIX_STACK 24, nmi_stack_correct, 1
1348 jmp nmi_stack_correct
1349
1350nmi_espfix_stack:
1351 /* We have a RING0_INT_FRAME here.
1352 *
1353 * create the pointer to lss back
1354 */
1355 pushl_cfi %ss
1356 pushl_cfi %esp
1357 addl $4, (%esp)
1358 /* copy the iret frame of 12 bytes */
1359 .rept 3
1360 pushl_cfi 16(%esp)
1361 .endr
1362 pushl_cfi %eax
1363 SAVE_ALL
1364 FIXUP_ESPFIX_STACK # %eax == %esp
1365 xorl %edx,%edx # zero error code
1366 call do_nmi
1367 RESTORE_REGS
1368 lss 12+4(%esp), %esp # back to espfix stack
1369 CFI_ADJUST_CFA_OFFSET -24
1370 jmp irq_return
1371 CFI_ENDPROC
1372END(nmi)
1373
1374ENTRY(int3)
1375 RING0_INT_FRAME
1376 pushl_cfi $-1 # mark this as an int
1377 SAVE_ALL
1378 TRACE_IRQS_OFF
1379 xorl %edx,%edx # zero error code
1380 movl %esp,%eax # pt_regs pointer
1381 call do_int3
1382 jmp ret_from_exception
1383 CFI_ENDPROC
1384END(int3)
1385
1386ENTRY(general_protection)
1387 RING0_EC_FRAME
1388 pushl_cfi $do_general_protection
1389 jmp error_code
1390 CFI_ENDPROC
1391END(general_protection)
1392
1393#ifdef CONFIG_KVM_GUEST
1394ENTRY(async_page_fault)
1395 RING0_EC_FRAME
1396 pushl_cfi $do_async_page_fault
1397 jmp error_code
1398 CFI_ENDPROC
1399END(async_page_fault)
1400#endif
1401
1402/*
1403 * End of kprobes section
1404 */
1405 .popsection