| blob | c097e7d607c61e27c4e6df0701f044f4af067ff7 |
1 /*
2 *
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 */
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 */
44 #include <linux/linkage.h>
45 #include <asm/thread_info.h>
46 #include <asm/irqflags.h>
47 #include <asm/errno.h>
48 #include <asm/segment.h>
49 #include <asm/smp.h>
50 #include <asm/page_types.h>
51 #include <asm/percpu.h>
52 #include <asm/dwarf2.h>
53 #include <asm/processor-flags.h>
54 #include <asm/ftrace.h>
55 #include <asm/irq_vectors.h>
57 /* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */
58 #include <linux/elf-em.h>
59 #define AUDIT_ARCH_I386 (EM_386|__AUDIT_ARCH_LE)
60 #define __AUDIT_ARCH_LE 0x40000000
62 #ifndef CONFIG_AUDITSYSCALL
63 #define sysenter_audit syscall_trace_entry
64 #define sysexit_audit syscall_exit_work
65 #endif
67 /*
68 * We use macros for low-level operations which need to be overridden
69 * for paravirtualization. The following will never clobber any registers:
70 * INTERRUPT_RETURN (aka. "iret")
71 * GET_CR0_INTO_EAX (aka. "movl %cr0, %eax")
72 * ENABLE_INTERRUPTS_SYSEXIT (aka "sti; sysexit").
73 *
74 * For DISABLE_INTERRUPTS/ENABLE_INTERRUPTS (aka "cli"/"sti"), you must
75 * specify what registers can be overwritten (CLBR_NONE, CLBR_EAX/EDX/ECX/ANY).
76 * Allowing a register to be clobbered can shrink the paravirt replacement
77 * enough to patch inline, increasing performance.
78 */
80 #define nr_syscalls ((syscall_table_size)/4)
82 #ifdef CONFIG_PREEMPT
83 #define preempt_stop(clobbers) DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF
84 #else
85 #define preempt_stop(clobbers)
86 #define resume_kernel restore_all
87 #endif
89 .macro TRACE_IRQS_IRET
90 #ifdef CONFIG_TRACE_IRQFLAGS
91 testl $X86_EFLAGS_IF,PT_EFLAGS(%esp) # interrupts off?
92 jz 1f
93 TRACE_IRQS_ON
94 1:
95 #endif
96 .endm
98 #ifdef CONFIG_VM86
99 #define resume_userspace_sig check_userspace
100 #else
101 #define resume_userspace_sig resume_userspace
102 #endif
104 /*
105 * User gs save/restore
106 *
107 * %gs is used for userland TLS and kernel only uses it for stack
108 * canary which is required to be at %gs:20 by gcc. Read the comment
109 * at the top of stackprotector.h for more info.
110 *
111 * Local labels 98 and 99 are used.
112 */
113 #ifdef CONFIG_X86_32_LAZY_GS
115 /* unfortunately push/pop can't be no-op */
116 .macro PUSH_GS
117 pushl $0
118 CFI_ADJUST_CFA_OFFSET 4
119 .endm
120 .macro POP_GS pop=0
121 addl $(4 + \pop), %esp
122 CFI_ADJUST_CFA_OFFSET -(4 + \pop)
123 .endm
124 .macro POP_GS_EX
125 .endm
127 /* all the rest are no-op */
128 .macro PTGS_TO_GS
129 .endm
130 .macro PTGS_TO_GS_EX
131 .endm
132 .macro GS_TO_REG reg
133 .endm
134 .macro REG_TO_PTGS reg
135 .endm
136 .macro SET_KERNEL_GS reg
137 .endm
139 #else /* CONFIG_X86_32_LAZY_GS */
141 .macro PUSH_GS
142 pushl %gs
143 CFI_ADJUST_CFA_OFFSET 4
144 /*CFI_REL_OFFSET gs, 0*/
145 .endm
147 .macro POP_GS pop=0
148 98: popl %gs
149 CFI_ADJUST_CFA_OFFSET -4
150 /*CFI_RESTORE gs*/
151 .if \pop <> 0
152 add $\pop, %esp
153 CFI_ADJUST_CFA_OFFSET -\pop
154 .endif
155 .endm
156 .macro POP_GS_EX
157 .pushsection .fixup, "ax"
158 99: movl $0, (%esp)
159 jmp 98b
160 .section __ex_table, "a"
161 .align 4
162 .long 98b, 99b
163 .popsection
164 .endm
166 .macro PTGS_TO_GS
167 98: mov PT_GS(%esp), %gs
168 .endm
169 .macro PTGS_TO_GS_EX
170 .pushsection .fixup, "ax"
171 99: movl $0, PT_GS(%esp)
172 jmp 98b
173 .section __ex_table, "a"
174 .align 4
175 .long 98b, 99b
176 .popsection
177 .endm
179 .macro GS_TO_REG reg
180 movl %gs, \reg
181 /*CFI_REGISTER gs, \reg*/
182 .endm
183 .macro REG_TO_PTGS reg
184 movl \reg, PT_GS(%esp)
185 /*CFI_REL_OFFSET gs, PT_GS*/
186 .endm
187 .macro SET_KERNEL_GS reg
188 movl $(__KERNEL_STACK_CANARY), \reg
189 movl \reg, %gs
190 .endm
192 #endif /* CONFIG_X86_32_LAZY_GS */
194 .macro SAVE_ALL
195 cld
196 PUSH_GS
197 pushl %fs
198 CFI_ADJUST_CFA_OFFSET 4
199 /*CFI_REL_OFFSET fs, 0;*/
200 pushl %es
201 CFI_ADJUST_CFA_OFFSET 4
202 /*CFI_REL_OFFSET es, 0;*/
203 pushl %ds
204 CFI_ADJUST_CFA_OFFSET 4
205 /*CFI_REL_OFFSET ds, 0;*/
206 pushl %eax
207 CFI_ADJUST_CFA_OFFSET 4
208 CFI_REL_OFFSET eax, 0
209 pushl %ebp
210 CFI_ADJUST_CFA_OFFSET 4
211 CFI_REL_OFFSET ebp, 0
212 pushl %edi
213 CFI_ADJUST_CFA_OFFSET 4
214 CFI_REL_OFFSET edi, 0
215 pushl %esi
216 CFI_ADJUST_CFA_OFFSET 4
217 CFI_REL_OFFSET esi, 0
218 pushl %edx
219 CFI_ADJUST_CFA_OFFSET 4
220 CFI_REL_OFFSET edx, 0
221 pushl %ecx
222 CFI_ADJUST_CFA_OFFSET 4
223 CFI_REL_OFFSET ecx, 0
224 pushl %ebx
225 CFI_ADJUST_CFA_OFFSET 4
226 CFI_REL_OFFSET ebx, 0
227 movl $(__USER_DS), %edx
228 movl %edx, %ds
229 movl %edx, %es
230 movl $(__KERNEL_PERCPU), %edx
231 movl %edx, %fs
232 SET_KERNEL_GS %edx
233 .endm
235 .macro RESTORE_INT_REGS
236 popl %ebx
237 CFI_ADJUST_CFA_OFFSET -4
238 CFI_RESTORE ebx
239 popl %ecx
240 CFI_ADJUST_CFA_OFFSET -4
241 CFI_RESTORE ecx
242 popl %edx
243 CFI_ADJUST_CFA_OFFSET -4
244 CFI_RESTORE edx
245 popl %esi
246 CFI_ADJUST_CFA_OFFSET -4
247 CFI_RESTORE esi
248 popl %edi
249 CFI_ADJUST_CFA_OFFSET -4
250 CFI_RESTORE edi
251 popl %ebp
252 CFI_ADJUST_CFA_OFFSET -4
253 CFI_RESTORE ebp
254 popl %eax
255 CFI_ADJUST_CFA_OFFSET -4
256 CFI_RESTORE eax
257 .endm
259 .macro RESTORE_REGS pop=0
260 RESTORE_INT_REGS
261 1: popl %ds
262 CFI_ADJUST_CFA_OFFSET -4
263 /*CFI_RESTORE ds;*/
264 2: popl %es
265 CFI_ADJUST_CFA_OFFSET -4
266 /*CFI_RESTORE es;*/
267 3: popl %fs
268 CFI_ADJUST_CFA_OFFSET -4
269 /*CFI_RESTORE fs;*/
270 POP_GS \pop
271 .pushsection .fixup, "ax"
272 4: movl $0, (%esp)
273 jmp 1b
274 5: movl $0, (%esp)
275 jmp 2b
276 6: movl $0, (%esp)
277 jmp 3b
278 .section __ex_table, "a"
279 .align 4
280 .long 1b, 4b
281 .long 2b, 5b
282 .long 3b, 6b
283 .popsection
284 POP_GS_EX
285 .endm
287 .macro RING0_INT_FRAME
288 CFI_STARTPROC simple
289 CFI_SIGNAL_FRAME
290 CFI_DEF_CFA esp, 3*4
291 /*CFI_OFFSET cs, -2*4;*/
292 CFI_OFFSET eip, -3*4
293 .endm
295 .macro RING0_EC_FRAME
296 CFI_STARTPROC simple
297 CFI_SIGNAL_FRAME
298 CFI_DEF_CFA esp, 4*4
299 /*CFI_OFFSET cs, -2*4;*/
300 CFI_OFFSET eip, -3*4
301 .endm
303 .macro RING0_PTREGS_FRAME
304 CFI_STARTPROC simple
305 CFI_SIGNAL_FRAME
306 CFI_DEF_CFA esp, PT_OLDESP-PT_EBX
307 /*CFI_OFFSET cs, PT_CS-PT_OLDESP;*/
308 CFI_OFFSET eip, PT_EIP-PT_OLDESP
309 /*CFI_OFFSET es, PT_ES-PT_OLDESP;*/
310 /*CFI_OFFSET ds, PT_DS-PT_OLDESP;*/
311 CFI_OFFSET eax, PT_EAX-PT_OLDESP
312 CFI_OFFSET ebp, PT_EBP-PT_OLDESP
313 CFI_OFFSET edi, PT_EDI-PT_OLDESP
314 CFI_OFFSET esi, PT_ESI-PT_OLDESP
315 CFI_OFFSET edx, PT_EDX-PT_OLDESP
316 CFI_OFFSET ecx, PT_ECX-PT_OLDESP
317 CFI_OFFSET ebx, PT_EBX-PT_OLDESP
318 .endm
320 ENTRY(ret_from_fork)
321 CFI_STARTPROC
322 pushl %eax
323 CFI_ADJUST_CFA_OFFSET 4
324 call schedule_tail
325 GET_THREAD_INFO(%ebp)
326 popl %eax
327 CFI_ADJUST_CFA_OFFSET -4
328 pushl $0x0202 # Reset kernel eflags
329 CFI_ADJUST_CFA_OFFSET 4
330 popfl
331 CFI_ADJUST_CFA_OFFSET -4
332 jmp syscall_exit
333 CFI_ENDPROC
334 END(ret_from_fork)
336 /*
337 * Return to user mode is not as complex as all this looks,
338 * but we want the default path for a system call return to
339 * go as quickly as possible which is why some of this is
340 * less clear than it otherwise should be.
341 */
343 # userspace resumption stub bypassing syscall exit tracing
344 ALIGN
345 RING0_PTREGS_FRAME
346 ret_from_exception:
347 preempt_stop(CLBR_ANY)
348 ret_from_intr:
349 GET_THREAD_INFO(%ebp)
350 check_userspace:
351 movl PT_EFLAGS(%esp), %eax # mix EFLAGS and CS
352 movb PT_CS(%esp), %al
353 andl $(X86_EFLAGS_VM | SEGMENT_RPL_MASK), %eax
354 cmpl $USER_RPL, %eax
355 jb resume_kernel # not returning to v8086 or userspace
357 ENTRY(resume_userspace)
358 LOCKDEP_SYS_EXIT
359 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
360 # setting need_resched or sigpending
361 # between sampling and the iret
362 TRACE_IRQS_OFF
363 movl TI_flags(%ebp), %ecx
364 andl $_TIF_WORK_MASK, %ecx # is there any work to be done on
365 # int/exception return?
366 jne work_pending
367 jmp restore_all
368 END(ret_from_exception)
370 #ifdef CONFIG_PREEMPT
371 ENTRY(resume_kernel)
372 DISABLE_INTERRUPTS(CLBR_ANY)
373 cmpl $0,TI_preempt_count(%ebp) # non-zero preempt_count ?
374 jnz restore_all
375 need_resched:
376 movl TI_flags(%ebp), %ecx # need_resched set ?
377 testb $_TIF_NEED_RESCHED, %cl
378 jz restore_all
379 testl $X86_EFLAGS_IF,PT_EFLAGS(%esp) # interrupts off (exception path) ?
380 jz restore_all
381 call preempt_schedule_irq
382 jmp need_resched
383 END(resume_kernel)
384 #endif
385 CFI_ENDPROC
387 /* SYSENTER_RETURN points to after the "sysenter" instruction in
388 the vsyscall page. See vsyscall-sysentry.S, which defines the symbol. */
390 # sysenter call handler stub
391 ENTRY(ia32_sysenter_target)
392 CFI_STARTPROC simple
393 CFI_SIGNAL_FRAME
394 CFI_DEF_CFA esp, 0
395 CFI_REGISTER esp, ebp
396 movl TSS_sysenter_sp0(%esp),%esp
397 sysenter_past_esp:
398 /*
399 * Interrupts are disabled here, but we can't trace it until
400 * enough kernel state to call TRACE_IRQS_OFF can be called - but
401 * we immediately enable interrupts at that point anyway.
402 */
403 pushl $(__USER_DS)
404 CFI_ADJUST_CFA_OFFSET 4
405 /*CFI_REL_OFFSET ss, 0*/
406 pushl %ebp
407 CFI_ADJUST_CFA_OFFSET 4
408 CFI_REL_OFFSET esp, 0
409 pushfl
410 orl $X86_EFLAGS_IF, (%esp)
411 CFI_ADJUST_CFA_OFFSET 4
412 pushl $(__USER_CS)
413 CFI_ADJUST_CFA_OFFSET 4
414 /*CFI_REL_OFFSET cs, 0*/
415 /*
416 * Push current_thread_info()->sysenter_return to the stack.
417 * A tiny bit of offset fixup is necessary - 4*4 means the 4 words
418 * pushed above; +8 corresponds to copy_thread's esp0 setting.
419 */
420 pushl (TI_sysenter_return-THREAD_SIZE+8+4*4)(%esp)
421 CFI_ADJUST_CFA_OFFSET 4
422 CFI_REL_OFFSET eip, 0
424 pushl %eax
425 CFI_ADJUST_CFA_OFFSET 4
426 SAVE_ALL
427 ENABLE_INTERRUPTS(CLBR_NONE)
429 /*
430 * Load the potential sixth argument from user stack.
431 * Careful about security.
432 */
433 cmpl $__PAGE_OFFSET-3,%ebp
434 jae syscall_fault
435 1: movl (%ebp),%ebp
436 movl %ebp,PT_EBP(%esp)
437 .section __ex_table,"a"
438 .align 4
439 .long 1b,syscall_fault
440 .previous
442 GET_THREAD_INFO(%ebp)
444 testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%ebp)
445 jnz sysenter_audit
446 sysenter_do_call:
447 cmpl $(nr_syscalls), %eax
448 jae syscall_badsys
449 call *sys_call_table(,%eax,4)
450 movl %eax,PT_EAX(%esp)
451 LOCKDEP_SYS_EXIT
452 DISABLE_INTERRUPTS(CLBR_ANY)
453 TRACE_IRQS_OFF
454 movl TI_flags(%ebp), %ecx
455 testl $_TIF_ALLWORK_MASK, %ecx
456 jne sysexit_audit
457 sysenter_exit:
458 /* if something modifies registers it must also disable sysexit */
459 movl PT_EIP(%esp), %edx
460 movl PT_OLDESP(%esp), %ecx
461 xorl %ebp,%ebp
462 TRACE_IRQS_ON
463 1: mov PT_FS(%esp), %fs
464 PTGS_TO_GS
465 ENABLE_INTERRUPTS_SYSEXIT
467 #ifdef CONFIG_AUDITSYSCALL
468 sysenter_audit:
469 testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
470 jnz syscall_trace_entry
471 addl $4,%esp
472 CFI_ADJUST_CFA_OFFSET -4
473 /* %esi already in 8(%esp) 6th arg: 4th syscall arg */
474 /* %edx already in 4(%esp) 5th arg: 3rd syscall arg */
475 /* %ecx already in 0(%esp) 4th arg: 2nd syscall arg */
476 movl %ebx,%ecx /* 3rd arg: 1st syscall arg */
477 movl %eax,%edx /* 2nd arg: syscall number */
478 movl $AUDIT_ARCH_I386,%eax /* 1st arg: audit arch */
479 call audit_syscall_entry
480 pushl %ebx
481 CFI_ADJUST_CFA_OFFSET 4
482 movl PT_EAX(%esp),%eax /* reload syscall number */
483 jmp sysenter_do_call
485 sysexit_audit:
486 testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %ecx
487 jne syscall_exit_work
488 TRACE_IRQS_ON
489 ENABLE_INTERRUPTS(CLBR_ANY)
490 movl %eax,%edx /* second arg, syscall return value */
491 cmpl $0,%eax /* is it < 0? */
492 setl %al /* 1 if so, 0 if not */
493 movzbl %al,%eax /* zero-extend that */
494 inc %eax /* first arg, 0->1(AUDITSC_SUCCESS), 1->2(AUDITSC_FAILURE) */
495 call audit_syscall_exit
496 DISABLE_INTERRUPTS(CLBR_ANY)
497 TRACE_IRQS_OFF
498 movl TI_flags(%ebp), %ecx
499 testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %ecx
500 jne syscall_exit_work
501 movl PT_EAX(%esp),%eax /* reload syscall return value */
502 jmp sysenter_exit
503 #endif
505 CFI_ENDPROC
506 .pushsection .fixup,"ax"
507 2: movl $0,PT_FS(%esp)
508 jmp 1b
509 .section __ex_table,"a"
510 .align 4
511 .long 1b,2b
512 .popsection
513 PTGS_TO_GS_EX
514 ENDPROC(ia32_sysenter_target)
516 # system call handler stub
517 ENTRY(system_call)
518 RING0_INT_FRAME # can't unwind into user space anyway
519 pushl %eax # save orig_eax
520 CFI_ADJUST_CFA_OFFSET 4
521 SAVE_ALL
522 GET_THREAD_INFO(%ebp)
523 # system call tracing in operation / emulation
524 testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%ebp)
525 jnz syscall_trace_entry
526 cmpl $(nr_syscalls), %eax
527 jae syscall_badsys
528 syscall_call:
529 call *sys_call_table(,%eax,4)
530 movl %eax,PT_EAX(%esp) # store the return value
531 syscall_exit:
532 LOCKDEP_SYS_EXIT
533 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
534 # setting need_resched or sigpending
535 # between sampling and the iret
536 TRACE_IRQS_OFF
537 movl TI_flags(%ebp), %ecx
538 testl $_TIF_ALLWORK_MASK, %ecx # current->work
539 jne syscall_exit_work
541 restore_all:
542 TRACE_IRQS_IRET
543 restore_all_notrace:
544 movl PT_EFLAGS(%esp), %eax # mix EFLAGS, SS and CS
545 # Warning: PT_OLDSS(%esp) contains the wrong/random values if we
546 # are returning to the kernel.
547 # See comments in process.c:copy_thread() for details.
548 movb PT_OLDSS(%esp), %ah
549 movb PT_CS(%esp), %al
550 andl $(X86_EFLAGS_VM | (SEGMENT_TI_MASK << 8) | SEGMENT_RPL_MASK), %eax
551 cmpl $((SEGMENT_LDT << 8) | USER_RPL), %eax
552 CFI_REMEMBER_STATE
553 je ldt_ss # returning to user-space with LDT SS
554 restore_nocheck:
555 RESTORE_REGS 4 # skip orig_eax/error_code
556 CFI_ADJUST_CFA_OFFSET -4
557 irq_return:
558 INTERRUPT_RETURN
559 .section .fixup,"ax"
560 ENTRY(iret_exc)
561 pushl $0 # no error code
562 pushl $do_iret_error
563 jmp error_code
564 .previous
565 .section __ex_table,"a"
566 .align 4
567 .long irq_return,iret_exc
568 .previous
570 CFI_RESTORE_STATE
571 ldt_ss:
572 larl PT_OLDSS(%esp), %eax
573 jnz restore_nocheck
574 testl $0x00400000, %eax # returning to 32bit stack?
575 jnz restore_nocheck # allright, normal return
577 #ifdef CONFIG_PARAVIRT
578 /*
579 * The kernel can't run on a non-flat stack if paravirt mode
580 * is active. Rather than try to fixup the high bits of
581 * ESP, bypass this code entirely. This may break DOSemu
582 * and/or Wine support in a paravirt VM, although the option
583 * is still available to implement the setting of the high
584 * 16-bits in the INTERRUPT_RETURN paravirt-op.
585 */
586 cmpl $0, pv_info+PARAVIRT_enabled
587 jne restore_nocheck
588 #endif
590 /*
591 * Setup and switch to ESPFIX stack
592 *
593 * We're returning to userspace with a 16 bit stack. The CPU will not
594 * restore the high word of ESP for us on executing iret... This is an
595 * "official" bug of all the x86-compatible CPUs, which we can work
596 * around to make dosemu and wine happy. We do this by preloading the
597 * high word of ESP with the high word of the userspace ESP while
598 * compensating for the offset by changing to the ESPFIX segment with
599 * a base address that matches for the difference.
600 */
601 mov %esp, %edx /* load kernel esp */
602 mov PT_OLDESP(%esp), %eax /* load userspace esp */
603 mov %dx, %ax /* eax: new kernel esp */
604 sub %eax, %edx /* offset (low word is 0) */
605 PER_CPU(gdt_page, %ebx)
606 shr $16, %edx
607 mov %dl, GDT_ENTRY_ESPFIX_SS * 8 + 4(%ebx) /* bits 16..23 */
608 mov %dh, GDT_ENTRY_ESPFIX_SS * 8 + 7(%ebx) /* bits 24..31 */
609 pushl $__ESPFIX_SS
610 CFI_ADJUST_CFA_OFFSET 4
611 push %eax /* new kernel esp */
612 CFI_ADJUST_CFA_OFFSET 4
613 /* Disable interrupts, but do not irqtrace this section: we
614 * will soon execute iret and the tracer was already set to
615 * the irqstate after the iret */
616 DISABLE_INTERRUPTS(CLBR_EAX)
617 lss (%esp), %esp /* switch to espfix segment */
618 CFI_ADJUST_CFA_OFFSET -8
619 jmp restore_nocheck
620 CFI_ENDPROC
621 ENDPROC(system_call)
623 # perform work that needs to be done immediately before resumption
624 ALIGN
625 RING0_PTREGS_FRAME # can't unwind into user space anyway
626 work_pending:
627 testb $_TIF_NEED_RESCHED, %cl
628 jz work_notifysig
629 work_resched:
630 call schedule
631 LOCKDEP_SYS_EXIT
632 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
633 # setting need_resched or sigpending
634 # between sampling and the iret
635 TRACE_IRQS_OFF
636 movl TI_flags(%ebp), %ecx
637 andl $_TIF_WORK_MASK, %ecx # is there any work to be done other
638 # than syscall tracing?
639 jz restore_all
640 testb $_TIF_NEED_RESCHED, %cl
641 jnz work_resched
643 work_notifysig: # deal with pending signals and
644 # notify-resume requests
645 #ifdef CONFIG_VM86
646 testl $X86_EFLAGS_VM, PT_EFLAGS(%esp)
647 movl %esp, %eax
648 jne work_notifysig_v86 # returning to kernel-space or
649 # vm86-space
650 xorl %edx, %edx
651 call do_notify_resume
652 jmp resume_userspace_sig
654 ALIGN
655 work_notifysig_v86:
656 pushl %ecx # save ti_flags for do_notify_resume
657 CFI_ADJUST_CFA_OFFSET 4
658 call save_v86_state # %eax contains pt_regs pointer
659 popl %ecx
660 CFI_ADJUST_CFA_OFFSET -4
661 movl %eax, %esp
662 #else
663 movl %esp, %eax
664 #endif
665 xorl %edx, %edx
666 call do_notify_resume
667 jmp resume_userspace_sig
668 END(work_pending)
670 # perform syscall exit tracing
671 ALIGN
672 syscall_trace_entry:
673 movl $-ENOSYS,PT_EAX(%esp)
674 movl %esp, %eax
675 call syscall_trace_enter
676 /* What it returned is what we'll actually use. */
677 cmpl $(nr_syscalls), %eax
678 jnae syscall_call
679 jmp syscall_exit
680 END(syscall_trace_entry)
682 # perform syscall exit tracing
683 ALIGN
684 syscall_exit_work:
685 testl $_TIF_WORK_SYSCALL_EXIT, %ecx
686 jz work_pending
687 TRACE_IRQS_ON
688 ENABLE_INTERRUPTS(CLBR_ANY) # could let syscall_trace_leave() call
689 # schedule() instead
690 movl %esp, %eax
691 call syscall_trace_leave
692 jmp resume_userspace
693 END(syscall_exit_work)
694 CFI_ENDPROC
696 RING0_INT_FRAME # can't unwind into user space anyway
697 syscall_fault:
698 GET_THREAD_INFO(%ebp)
699 movl $-EFAULT,PT_EAX(%esp)
700 jmp resume_userspace
701 END(syscall_fault)
703 syscall_badsys:
704 movl $-ENOSYS,PT_EAX(%esp)
705 jmp resume_userspace
706 END(syscall_badsys)
707 CFI_ENDPROC
709 /*
710 * System calls that need a pt_regs pointer.
711 */
712 #define PTREGSCALL(name) \
713 ALIGN; \
714 ptregs_##name: \
715 leal 4(%esp),%eax; \
716 jmp sys_##name;
718 PTREGSCALL(iopl)
719 PTREGSCALL(fork)
720 PTREGSCALL(clone)
721 PTREGSCALL(vfork)
722 PTREGSCALL(execve)
723 PTREGSCALL(sigaltstack)
724 PTREGSCALL(sigreturn)
725 PTREGSCALL(rt_sigreturn)
726 PTREGSCALL(vm86)
727 PTREGSCALL(vm86old)
729 .macro FIXUP_ESPFIX_STACK
730 /*
731 * Switch back for ESPFIX stack to the normal zerobased stack
732 *
733 * We can't call C functions using the ESPFIX stack. This code reads
734 * the high word of the segment base from the GDT and swiches to the
735 * normal stack and adjusts ESP with the matching offset.
736 */
737 /* fixup the stack */
738 PER_CPU(gdt_page, %ebx)
739 mov GDT_ENTRY_ESPFIX_SS * 8 + 4(%ebx), %al /* bits 16..23 */
740 mov GDT_ENTRY_ESPFIX_SS * 8 + 7(%ebx), %ah /* bits 24..31 */
741 shl $16, %eax
742 addl %esp, %eax /* the adjusted stack pointer */
743 pushl $__KERNEL_DS
744 CFI_ADJUST_CFA_OFFSET 4
745 pushl %eax
746 CFI_ADJUST_CFA_OFFSET 4
747 lss (%esp), %esp /* switch to the normal stack segment */
748 CFI_ADJUST_CFA_OFFSET -8
749 .endm
750 .macro UNWIND_ESPFIX_STACK
751 movl %ss, %eax
752 /* see if on espfix stack */
753 cmpw $__ESPFIX_SS, %ax
754 jne 27f
755 movl $__KERNEL_DS, %eax
756 movl %eax, %ds
757 movl %eax, %es
758 /* switch to normal stack */
759 FIXUP_ESPFIX_STACK
760 27:
761 .endm
763 /*
764 * Build the entry stubs and pointer table with some assembler magic.
765 * We pack 7 stubs into a single 32-byte chunk, which will fit in a
766 * single cache line on all modern x86 implementations.
767 */
768 .section .init.rodata,"a"
769 ENTRY(interrupt)
770 .text
771 .p2align 5
772 .p2align CONFIG_X86_L1_CACHE_SHIFT
773 ENTRY(irq_entries_start)
774 RING0_INT_FRAME
775 vector=FIRST_EXTERNAL_VECTOR
776 .rept (NR_VECTORS-FIRST_EXTERNAL_VECTOR+6)/7
777 .balign 32
778 .rept 7
779 .if vector < NR_VECTORS
780 .if vector <> FIRST_EXTERNAL_VECTOR
781 CFI_ADJUST_CFA_OFFSET -4
782 .endif
783 1: pushl $(~vector+0x80) /* Note: always in signed byte range */
784 CFI_ADJUST_CFA_OFFSET 4
785 .if ((vector-FIRST_EXTERNAL_VECTOR)%7) <> 6
786 jmp 2f
787 .endif
788 .previous
789 .long 1b
790 .text
791 vector=vector+1
792 .endif
793 .endr
794 2: jmp common_interrupt
795 .endr
796 END(irq_entries_start)
798 .previous
799 END(interrupt)
800 .previous
802 /*
803 * the CPU automatically disables interrupts when executing an IRQ vector,
804 * so IRQ-flags tracing has to follow that:
805 */
806 .p2align CONFIG_X86_L1_CACHE_SHIFT
807 common_interrupt:
808 addl $-0x80,(%esp) /* Adjust vector into the [-256,-1] range */
809 SAVE_ALL
810 TRACE_IRQS_OFF
811 movl %esp,%eax
812 call do_IRQ
813 jmp ret_from_intr
814 ENDPROC(common_interrupt)
815 CFI_ENDPROC
817 #define BUILD_INTERRUPT3(name, nr, fn) \
818 ENTRY(name) \
819 RING0_INT_FRAME; \
820 pushl $~(nr); \
821 CFI_ADJUST_CFA_OFFSET 4; \
822 SAVE_ALL; \
823 TRACE_IRQS_OFF \
824 movl %esp,%eax; \
825 call fn; \
826 jmp ret_from_intr; \
827 CFI_ENDPROC; \
828 ENDPROC(name)
830 #define BUILD_INTERRUPT(name, nr) BUILD_INTERRUPT3(name, nr, smp_##name)
832 /* The include is where all of the SMP etc. interrupts come from */
833 #include <asm/entry_arch.h>
835 ENTRY(coprocessor_error)
836 RING0_INT_FRAME
837 pushl $0
838 CFI_ADJUST_CFA_OFFSET 4
839 pushl $do_coprocessor_error
840 CFI_ADJUST_CFA_OFFSET 4
841 jmp error_code
842 CFI_ENDPROC
843 END(coprocessor_error)
845 ENTRY(simd_coprocessor_error)
846 RING0_INT_FRAME
847 pushl $0
848 CFI_ADJUST_CFA_OFFSET 4
849 pushl $do_simd_coprocessor_error
850 CFI_ADJUST_CFA_OFFSET 4
851 jmp error_code
852 CFI_ENDPROC
853 END(simd_coprocessor_error)
855 ENTRY(device_not_available)
856 RING0_INT_FRAME
857 pushl $-1 # mark this as an int
858 CFI_ADJUST_CFA_OFFSET 4
859 pushl $do_device_not_available
860 CFI_ADJUST_CFA_OFFSET 4
861 jmp error_code
862 CFI_ENDPROC
863 END(device_not_available)
865 #ifdef CONFIG_PARAVIRT
866 ENTRY(native_iret)
867 iret
868 .section __ex_table,"a"
869 .align 4
870 .long native_iret, iret_exc
871 .previous
872 END(native_iret)
874 ENTRY(native_irq_enable_sysexit)
875 sti
876 sysexit
877 END(native_irq_enable_sysexit)
878 #endif
880 ENTRY(overflow)
881 RING0_INT_FRAME
882 pushl $0
883 CFI_ADJUST_CFA_OFFSET 4
884 pushl $do_overflow
885 CFI_ADJUST_CFA_OFFSET 4
886 jmp error_code
887 CFI_ENDPROC
888 END(overflow)
890 ENTRY(bounds)
891 RING0_INT_FRAME
892 pushl $0
893 CFI_ADJUST_CFA_OFFSET 4
894 pushl $do_bounds
895 CFI_ADJUST_CFA_OFFSET 4
896 jmp error_code
897 CFI_ENDPROC
898 END(bounds)
900 ENTRY(invalid_op)
901 RING0_INT_FRAME
902 pushl $0
903 CFI_ADJUST_CFA_OFFSET 4
904 pushl $do_invalid_op
905 CFI_ADJUST_CFA_OFFSET 4
906 jmp error_code
907 CFI_ENDPROC
908 END(invalid_op)
910 ENTRY(coprocessor_segment_overrun)
911 RING0_INT_FRAME
912 pushl $0
913 CFI_ADJUST_CFA_OFFSET 4
914 pushl $do_coprocessor_segment_overrun
915 CFI_ADJUST_CFA_OFFSET 4
916 jmp error_code
917 CFI_ENDPROC
918 END(coprocessor_segment_overrun)
920 ENTRY(invalid_TSS)
921 RING0_EC_FRAME
922 pushl $do_invalid_TSS
923 CFI_ADJUST_CFA_OFFSET 4
924 jmp error_code
925 CFI_ENDPROC
926 END(invalid_TSS)
928 ENTRY(segment_not_present)
929 RING0_EC_FRAME
930 pushl $do_segment_not_present
931 CFI_ADJUST_CFA_OFFSET 4
932 jmp error_code
933 CFI_ENDPROC
934 END(segment_not_present)
936 ENTRY(stack_segment)
937 RING0_EC_FRAME
938 pushl $do_stack_segment
939 CFI_ADJUST_CFA_OFFSET 4
940 jmp error_code
941 CFI_ENDPROC
942 END(stack_segment)
944 ENTRY(alignment_check)
945 RING0_EC_FRAME
946 pushl $do_alignment_check
947 CFI_ADJUST_CFA_OFFSET 4
948 jmp error_code
949 CFI_ENDPROC
950 END(alignment_check)
952 ENTRY(divide_error)
953 RING0_INT_FRAME
954 pushl $0 # no error code
955 CFI_ADJUST_CFA_OFFSET 4
956 pushl $do_divide_error
957 CFI_ADJUST_CFA_OFFSET 4
958 jmp error_code
959 CFI_ENDPROC
960 END(divide_error)
962 #ifdef CONFIG_X86_MCE
963 ENTRY(machine_check)
964 RING0_INT_FRAME
965 pushl $0
966 CFI_ADJUST_CFA_OFFSET 4
967 pushl machine_check_vector
968 CFI_ADJUST_CFA_OFFSET 4
969 jmp error_code
970 CFI_ENDPROC
971 END(machine_check)
972 #endif
974 ENTRY(spurious_interrupt_bug)
975 RING0_INT_FRAME
976 pushl $0
977 CFI_ADJUST_CFA_OFFSET 4
978 pushl $do_spurious_interrupt_bug
979 CFI_ADJUST_CFA_OFFSET 4
980 jmp error_code
981 CFI_ENDPROC
982 END(spurious_interrupt_bug)
984 ENTRY(kernel_thread_helper)
985 pushl $0 # fake return address for unwinder
986 CFI_STARTPROC
987 movl %edx,%eax
988 push %edx
989 CFI_ADJUST_CFA_OFFSET 4
990 call *%ebx
991 push %eax
992 CFI_ADJUST_CFA_OFFSET 4
993 call do_exit
994 ud2 # padding for call trace
995 CFI_ENDPROC
996 ENDPROC(kernel_thread_helper)
998 #ifdef CONFIG_XEN
999 /* Xen doesn't set %esp to be precisely what the normal sysenter
1000 entrypoint expects, so fix it up before using the normal path. */
1001 ENTRY(xen_sysenter_target)
1002 RING0_INT_FRAME
1003 addl $5*4, %esp /* remove xen-provided frame */
1004 CFI_ADJUST_CFA_OFFSET -5*4
1005 jmp sysenter_past_esp
1006 CFI_ENDPROC
1008 ENTRY(xen_hypervisor_callback)
1009 CFI_STARTPROC
1010 pushl $0
1011 CFI_ADJUST_CFA_OFFSET 4
1012 SAVE_ALL
1013 TRACE_IRQS_OFF
1015 /* Check to see if we got the event in the critical
1016 region in xen_iret_direct, after we've reenabled
1017 events and checked for pending events. This simulates
1018 iret instruction's behaviour where it delivers a
1019 pending interrupt when enabling interrupts. */
1020 movl PT_EIP(%esp),%eax
1021 cmpl $xen_iret_start_crit,%eax
1022 jb 1f
1023 cmpl $xen_iret_end_crit,%eax
1024 jae 1f
1026 jmp xen_iret_crit_fixup
1028 ENTRY(xen_do_upcall)
1029 1: mov %esp, %eax
1030 call xen_evtchn_do_upcall
1031 jmp ret_from_intr
1032 CFI_ENDPROC
1033 ENDPROC(xen_hypervisor_callback)
1035 # Hypervisor uses this for application faults while it executes.
1036 # We get here for two reasons:
1037 # 1. Fault while reloading DS, ES, FS or GS
1038 # 2. Fault while executing IRET
1039 # Category 1 we fix up by reattempting the load, and zeroing the segment
1040 # register if the load fails.
1041 # Category 2 we fix up by jumping to do_iret_error. We cannot use the
1042 # normal Linux return path in this case because if we use the IRET hypercall
1043 # to pop the stack frame we end up in an infinite loop of failsafe callbacks.
1044 # We distinguish between categories by maintaining a status value in EAX.
1045 ENTRY(xen_failsafe_callback)
1046 CFI_STARTPROC
1047 pushl %eax
1048 CFI_ADJUST_CFA_OFFSET 4
1049 movl $1,%eax
1050 1: mov 4(%esp),%ds
1051 2: mov 8(%esp),%es
1052 3: mov 12(%esp),%fs
1053 4: mov 16(%esp),%gs
1054 testl %eax,%eax
1055 popl %eax
1056 CFI_ADJUST_CFA_OFFSET -4
1057 lea 16(%esp),%esp
1058 CFI_ADJUST_CFA_OFFSET -16
1059 jz 5f
1060 addl $16,%esp
1061 jmp iret_exc # EAX != 0 => Category 2 (Bad IRET)
1062 5: pushl $0 # EAX == 0 => Category 1 (Bad segment)
1063 CFI_ADJUST_CFA_OFFSET 4
1064 SAVE_ALL
1065 jmp ret_from_exception
1066 CFI_ENDPROC
1068 .section .fixup,"ax"
1069 6: xorl %eax,%eax
1070 movl %eax,4(%esp)
1071 jmp 1b
1072 7: xorl %eax,%eax
1073 movl %eax,8(%esp)
1074 jmp 2b
1075 8: xorl %eax,%eax
1076 movl %eax,12(%esp)
1077 jmp 3b
1078 9: xorl %eax,%eax
1079 movl %eax,16(%esp)
1080 jmp 4b
1081 .previous
1082 .section __ex_table,"a"
1083 .align 4
1084 .long 1b,6b
1085 .long 2b,7b
1086 .long 3b,8b
1087 .long 4b,9b
1088 .previous
1089 ENDPROC(xen_failsafe_callback)
1091 #endif /* CONFIG_XEN */
1093 #ifdef CONFIG_FUNCTION_TRACER
1094 #ifdef CONFIG_DYNAMIC_FTRACE
1096 ENTRY(mcount)
1097 ret
1098 END(mcount)
1100 ENTRY(ftrace_caller)
1101 cmpl $0, function_trace_stop
1102 jne ftrace_stub
1104 pushl %eax
1105 pushl %ecx
1106 pushl %edx
1107 movl 0xc(%esp), %eax
1108 movl 0x4(%ebp), %edx
1109 subl $MCOUNT_INSN_SIZE, %eax
1111 .globl ftrace_call
1112 ftrace_call:
1113 call ftrace_stub
1115 popl %edx
1116 popl %ecx
1117 popl %eax
1118 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1119 .globl ftrace_graph_call
1120 ftrace_graph_call:
1121 jmp ftrace_stub
1122 #endif
1124 .globl ftrace_stub
1125 ftrace_stub:
1126 ret
1127 END(ftrace_caller)
1129 #else /* ! CONFIG_DYNAMIC_FTRACE */
1131 ENTRY(mcount)
1132 cmpl $0, function_trace_stop
1133 jne ftrace_stub
1135 cmpl $ftrace_stub, ftrace_trace_function
1136 jnz trace
1137 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1138 cmpl $ftrace_stub, ftrace_graph_return
1139 jnz ftrace_graph_caller
1141 cmpl $ftrace_graph_entry_stub, ftrace_graph_entry
1142 jnz ftrace_graph_caller
1143 #endif
1144 .globl ftrace_stub
1145 ftrace_stub:
1146 ret
1148 /* taken from glibc */
1149 trace:
1150 pushl %eax
1151 pushl %ecx
1152 pushl %edx
1153 movl 0xc(%esp), %eax
1154 movl 0x4(%ebp), %edx
1155 subl $MCOUNT_INSN_SIZE, %eax
1157 call *ftrace_trace_function
1159 popl %edx
1160 popl %ecx
1161 popl %eax
1162 jmp ftrace_stub
1163 END(mcount)
1164 #endif /* CONFIG_DYNAMIC_FTRACE */
1165 #endif /* CONFIG_FUNCTION_TRACER */
1167 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1168 ENTRY(ftrace_graph_caller)
1169 cmpl $0, function_trace_stop
1170 jne ftrace_stub
1172 pushl %eax
1173 pushl %ecx
1174 pushl %edx
1175 movl 0xc(%esp), %edx
1176 lea 0x4(%ebp), %eax
1177 movl (%ebp), %ecx
1178 subl $MCOUNT_INSN_SIZE, %edx
1179 call prepare_ftrace_return
1180 popl %edx
1181 popl %ecx
1182 popl %eax
1183 ret
1184 END(ftrace_graph_caller)
1186 .globl return_to_handler
1187 return_to_handler:
1188 pushl $0
1189 pushl %eax
1190 pushl %ecx
1191 pushl %edx
1192 movl %ebp, %eax
1193 call ftrace_return_to_handler
1194 movl %eax, 0xc(%esp)
1195 popl %edx
1196 popl %ecx
1197 popl %eax
1198 ret
1199 #endif
1201 .section .rodata,"a"
1202 #include "syscall_table_32.S"
1204 syscall_table_size=(.-sys_call_table)
1206 /*
1207 * Some functions should be protected against kprobes
1208 */
1209 .pushsection .kprobes.text, "ax"
1211 ENTRY(page_fault)
1212 RING0_EC_FRAME
1213 pushl $do_page_fault
1214 CFI_ADJUST_CFA_OFFSET 4
1215 ALIGN
1216 error_code:
1217 /* the function address is in %gs's slot on the stack */
1218 pushl %fs
1219 CFI_ADJUST_CFA_OFFSET 4
1220 /*CFI_REL_OFFSET fs, 0*/
1221 pushl %es
1222 CFI_ADJUST_CFA_OFFSET 4
1223 /*CFI_REL_OFFSET es, 0*/
1224 pushl %ds
1225 CFI_ADJUST_CFA_OFFSET 4
1226 /*CFI_REL_OFFSET ds, 0*/
1227 pushl %eax
1228 CFI_ADJUST_CFA_OFFSET 4
1229 CFI_REL_OFFSET eax, 0
1230 pushl %ebp
1231 CFI_ADJUST_CFA_OFFSET 4
1232 CFI_REL_OFFSET ebp, 0
1233 pushl %edi
1234 CFI_ADJUST_CFA_OFFSET 4
1235 CFI_REL_OFFSET edi, 0
1236 pushl %esi
1237 CFI_ADJUST_CFA_OFFSET 4
1238 CFI_REL_OFFSET esi, 0
1239 pushl %edx
1240 CFI_ADJUST_CFA_OFFSET 4
1241 CFI_REL_OFFSET edx, 0
1242 pushl %ecx
1243 CFI_ADJUST_CFA_OFFSET 4
1244 CFI_REL_OFFSET ecx, 0
1245 pushl %ebx
1246 CFI_ADJUST_CFA_OFFSET 4
1247 CFI_REL_OFFSET ebx, 0
1248 cld
1249 movl $(__KERNEL_PERCPU), %ecx
1250 movl %ecx, %fs
1251 UNWIND_ESPFIX_STACK
1252 GS_TO_REG %ecx
1253 movl PT_GS(%esp), %edi # get the function address
1254 movl PT_ORIG_EAX(%esp), %edx # get the error code
1255 movl $-1, PT_ORIG_EAX(%esp) # no syscall to restart
1256 REG_TO_PTGS %ecx
1257 SET_KERNEL_GS %ecx
1258 movl $(__USER_DS), %ecx
1259 movl %ecx, %ds
1260 movl %ecx, %es
1261 TRACE_IRQS_OFF
1262 movl %esp,%eax # pt_regs pointer
1263 call *%edi
1264 jmp ret_from_exception
1265 CFI_ENDPROC
1266 END(page_fault)
1268 /*
1269 * Debug traps and NMI can happen at the one SYSENTER instruction
1270 * that sets up the real kernel stack. Check here, since we can't
1271 * allow the wrong stack to be used.
1272 *
1273 * "TSS_sysenter_sp0+12" is because the NMI/debug handler will have
1274 * already pushed 3 words if it hits on the sysenter instruction:
1275 * eflags, cs and eip.
1276 *
1277 * We just load the right stack, and push the three (known) values
1278 * by hand onto the new stack - while updating the return eip past
1279 * the instruction that would have done it for sysenter.
1280 */
1281 .macro FIX_STACK offset ok label
1282 cmpw $__KERNEL_CS, 4(%esp)
1283 jne \ok
1284 \label:
1285 movl TSS_sysenter_sp0 + \offset(%esp), %esp
1286 CFI_DEF_CFA esp, 0
1287 CFI_UNDEFINED eip
1288 pushfl
1289 CFI_ADJUST_CFA_OFFSET 4
1290 pushl $__KERNEL_CS
1291 CFI_ADJUST_CFA_OFFSET 4
1292 pushl $sysenter_past_esp
1293 CFI_ADJUST_CFA_OFFSET 4
1294 CFI_REL_OFFSET eip, 0
1295 .endm
1297 ENTRY(debug)
1298 RING0_INT_FRAME
1299 cmpl $ia32_sysenter_target,(%esp)
1300 jne debug_stack_correct
1301 FIX_STACK 12, debug_stack_correct, debug_esp_fix_insn
1302 debug_stack_correct:
1303 pushl $-1 # mark this as an int
1304 CFI_ADJUST_CFA_OFFSET 4
1305 SAVE_ALL
1306 TRACE_IRQS_OFF
1307 xorl %edx,%edx # error code 0
1308 movl %esp,%eax # pt_regs pointer
1309 call do_debug
1310 jmp ret_from_exception
1311 CFI_ENDPROC
1312 END(debug)
1314 /*
1315 * NMI is doubly nasty. It can happen _while_ we're handling
1316 * a debug fault, and the debug fault hasn't yet been able to
1317 * clear up the stack. So we first check whether we got an
1318 * NMI on the sysenter entry path, but after that we need to
1319 * check whether we got an NMI on the debug path where the debug
1320 * fault happened on the sysenter path.
1321 */
1322 ENTRY(nmi)
1323 RING0_INT_FRAME
1324 pushl %eax
1325 CFI_ADJUST_CFA_OFFSET 4
1326 movl %ss, %eax
1327 cmpw $__ESPFIX_SS, %ax
1328 popl %eax
1329 CFI_ADJUST_CFA_OFFSET -4
1330 je nmi_espfix_stack
1331 cmpl $ia32_sysenter_target,(%esp)
1332 je nmi_stack_fixup
1333 pushl %eax
1334 CFI_ADJUST_CFA_OFFSET 4
1335 movl %esp,%eax
1336 /* Do not access memory above the end of our stack page,
1337 * it might not exist.
1338 */
1339 andl $(THREAD_SIZE-1),%eax
1340 cmpl $(THREAD_SIZE-20),%eax
1341 popl %eax
1342 CFI_ADJUST_CFA_OFFSET -4
1343 jae nmi_stack_correct
1344 cmpl $ia32_sysenter_target,12(%esp)
1345 je nmi_debug_stack_check
1346 nmi_stack_correct:
1347 /* We have a RING0_INT_FRAME here */
1348 pushl %eax
1349 CFI_ADJUST_CFA_OFFSET 4
1350 SAVE_ALL
1351 xorl %edx,%edx # zero error code
1352 movl %esp,%eax # pt_regs pointer
1353 call do_nmi
1354 jmp restore_all_notrace
1355 CFI_ENDPROC
1357 nmi_stack_fixup:
1358 RING0_INT_FRAME
1359 FIX_STACK 12, nmi_stack_correct, 1
1360 jmp nmi_stack_correct
1362 nmi_debug_stack_check:
1363 /* We have a RING0_INT_FRAME here */
1364 cmpw $__KERNEL_CS,16(%esp)
1365 jne nmi_stack_correct
1366 cmpl $debug,(%esp)
1367 jb nmi_stack_correct
1368 cmpl $debug_esp_fix_insn,(%esp)
1369 ja nmi_stack_correct
1370 FIX_STACK 24, nmi_stack_correct, 1
1371 jmp nmi_stack_correct
1373 nmi_espfix_stack:
1374 /* We have a RING0_INT_FRAME here.
1375 *
1376 * create the pointer to lss back
1377 */
1378 pushl %ss
1379 CFI_ADJUST_CFA_OFFSET 4
1380 pushl %esp
1381 CFI_ADJUST_CFA_OFFSET 4
1382 addl $4, (%esp)
1383 /* copy the iret frame of 12 bytes */
1384 .rept 3
1385 pushl 16(%esp)
1386 CFI_ADJUST_CFA_OFFSET 4
1387 .endr
1388 pushl %eax
1389 CFI_ADJUST_CFA_OFFSET 4
1390 SAVE_ALL
1391 FIXUP_ESPFIX_STACK # %eax == %esp
1392 xorl %edx,%edx # zero error code
1393 call do_nmi
1394 RESTORE_REGS
1395 lss 12+4(%esp), %esp # back to espfix stack
1396 CFI_ADJUST_CFA_OFFSET -24
1397 jmp irq_return
1398 CFI_ENDPROC
1399 END(nmi)
1401 ENTRY(int3)
1402 RING0_INT_FRAME
1403 pushl $-1 # mark this as an int
1404 CFI_ADJUST_CFA_OFFSET 4
1405 SAVE_ALL
1406 TRACE_IRQS_OFF
1407 xorl %edx,%edx # zero error code
1408 movl %esp,%eax # pt_regs pointer
1409 call do_int3
1410 jmp ret_from_exception
1411 CFI_ENDPROC
1412 END(int3)
1414 ENTRY(general_protection)
1415 RING0_EC_FRAME
1416 pushl $do_general_protection
1417 CFI_ADJUST_CFA_OFFSET 4
1418 jmp error_code
1419 CFI_ENDPROC
1420 END(general_protection)
1422 /*
1423 * End of kprobes section
1424 */
1425 .popsection