| blob | 6ed91d9980e240b73fa824f7db00d8065d145316 |
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 <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 #include <asm/smap.h>
62 /* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */
63 #include <linux/elf-em.h>
64 #define AUDIT_ARCH_I386 (EM_386|__AUDIT_ARCH_LE)
65 #define __AUDIT_ARCH_LE 0x40000000
67 #ifndef CONFIG_AUDITSYSCALL
68 #define sysenter_audit syscall_trace_entry
69 #define sysexit_audit syscall_exit_work
70 #endif
72 .section .entry.text, "ax"
74 /*
75 * We use macros for low-level operations which need to be overridden
76 * for paravirtualization. The following will never clobber any registers:
77 * INTERRUPT_RETURN (aka. "iret")
78 * GET_CR0_INTO_EAX (aka. "movl %cr0, %eax")
79 * ENABLE_INTERRUPTS_SYSEXIT (aka "sti; sysexit").
80 *
81 * For DISABLE_INTERRUPTS/ENABLE_INTERRUPTS (aka "cli"/"sti"), you must
82 * specify what registers can be overwritten (CLBR_NONE, CLBR_EAX/EDX/ECX/ANY).
83 * Allowing a register to be clobbered can shrink the paravirt replacement
84 * enough to patch inline, increasing performance.
85 */
87 #ifdef CONFIG_PREEMPT
88 #define preempt_stop(clobbers) DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF
89 #else
90 #define preempt_stop(clobbers)
91 #define resume_kernel restore_all
92 #endif
94 .macro TRACE_IRQS_IRET
95 #ifdef CONFIG_TRACE_IRQFLAGS
96 testl $X86_EFLAGS_IF,PT_EFLAGS(%esp) # interrupts off?
97 jz 1f
98 TRACE_IRQS_ON
99 1:
100 #endif
101 .endm
103 /*
104 * User gs save/restore
105 *
106 * %gs is used for userland TLS and kernel only uses it for stack
107 * canary which is required to be at %gs:20 by gcc. Read the comment
108 * at the top of stackprotector.h for more info.
109 *
110 * Local labels 98 and 99 are used.
111 */
112 #ifdef CONFIG_X86_32_LAZY_GS
114 /* unfortunately push/pop can't be no-op */
115 .macro PUSH_GS
116 pushl_cfi $0
117 .endm
118 .macro POP_GS pop=0
119 addl $(4 + \pop), %esp
120 CFI_ADJUST_CFA_OFFSET -(4 + \pop)
121 .endm
122 .macro POP_GS_EX
123 .endm
125 /* all the rest are no-op */
126 .macro PTGS_TO_GS
127 .endm
128 .macro PTGS_TO_GS_EX
129 .endm
130 .macro GS_TO_REG reg
131 .endm
132 .macro REG_TO_PTGS reg
133 .endm
134 .macro SET_KERNEL_GS reg
135 .endm
137 #else /* CONFIG_X86_32_LAZY_GS */
139 .macro PUSH_GS
140 pushl_cfi %gs
141 /*CFI_REL_OFFSET gs, 0*/
142 .endm
144 .macro POP_GS pop=0
145 98: popl_cfi %gs
146 /*CFI_RESTORE gs*/
147 .if \pop <> 0
148 add $\pop, %esp
149 CFI_ADJUST_CFA_OFFSET -\pop
150 .endif
151 .endm
152 .macro POP_GS_EX
153 .pushsection .fixup, "ax"
154 99: movl $0, (%esp)
155 jmp 98b
156 .popsection
157 _ASM_EXTABLE(98b,99b)
158 .endm
160 .macro PTGS_TO_GS
161 98: mov PT_GS(%esp), %gs
162 .endm
163 .macro PTGS_TO_GS_EX
164 .pushsection .fixup, "ax"
165 99: movl $0, PT_GS(%esp)
166 jmp 98b
167 .popsection
168 _ASM_EXTABLE(98b,99b)
169 .endm
171 .macro GS_TO_REG reg
172 movl %gs, \reg
173 /*CFI_REGISTER gs, \reg*/
174 .endm
175 .macro REG_TO_PTGS reg
176 movl \reg, PT_GS(%esp)
177 /*CFI_REL_OFFSET gs, PT_GS*/
178 .endm
179 .macro SET_KERNEL_GS reg
180 movl $(__KERNEL_STACK_CANARY), \reg
181 movl \reg, %gs
182 .endm
184 #endif /* CONFIG_X86_32_LAZY_GS */
186 .macro SAVE_ALL
187 cld
188 PUSH_GS
189 pushl_cfi %fs
190 /*CFI_REL_OFFSET fs, 0;*/
191 pushl_cfi %es
192 /*CFI_REL_OFFSET es, 0;*/
193 pushl_cfi %ds
194 /*CFI_REL_OFFSET ds, 0;*/
195 pushl_cfi %eax
196 CFI_REL_OFFSET eax, 0
197 pushl_cfi %ebp
198 CFI_REL_OFFSET ebp, 0
199 pushl_cfi %edi
200 CFI_REL_OFFSET edi, 0
201 pushl_cfi %esi
202 CFI_REL_OFFSET esi, 0
203 pushl_cfi %edx
204 CFI_REL_OFFSET edx, 0
205 pushl_cfi %ecx
206 CFI_REL_OFFSET ecx, 0
207 pushl_cfi %ebx
208 CFI_REL_OFFSET ebx, 0
209 movl $(__USER_DS), %edx
210 movl %edx, %ds
211 movl %edx, %es
212 movl $(__KERNEL_PERCPU), %edx
213 movl %edx, %fs
214 SET_KERNEL_GS %edx
215 .endm
217 .macro RESTORE_INT_REGS
218 popl_cfi %ebx
219 CFI_RESTORE ebx
220 popl_cfi %ecx
221 CFI_RESTORE ecx
222 popl_cfi %edx
223 CFI_RESTORE edx
224 popl_cfi %esi
225 CFI_RESTORE esi
226 popl_cfi %edi
227 CFI_RESTORE edi
228 popl_cfi %ebp
229 CFI_RESTORE ebp
230 popl_cfi %eax
231 CFI_RESTORE eax
232 .endm
234 .macro RESTORE_REGS pop=0
235 RESTORE_INT_REGS
236 1: popl_cfi %ds
237 /*CFI_RESTORE ds;*/
238 2: popl_cfi %es
239 /*CFI_RESTORE es;*/
240 3: popl_cfi %fs
241 /*CFI_RESTORE fs;*/
242 POP_GS \pop
243 .pushsection .fixup, "ax"
244 4: movl $0, (%esp)
245 jmp 1b
246 5: movl $0, (%esp)
247 jmp 2b
248 6: movl $0, (%esp)
249 jmp 3b
250 .popsection
251 _ASM_EXTABLE(1b,4b)
252 _ASM_EXTABLE(2b,5b)
253 _ASM_EXTABLE(3b,6b)
254 POP_GS_EX
255 .endm
257 .macro RING0_INT_FRAME
258 CFI_STARTPROC simple
259 CFI_SIGNAL_FRAME
260 CFI_DEF_CFA esp, 3*4
261 /*CFI_OFFSET cs, -2*4;*/
262 CFI_OFFSET eip, -3*4
263 .endm
265 .macro RING0_EC_FRAME
266 CFI_STARTPROC simple
267 CFI_SIGNAL_FRAME
268 CFI_DEF_CFA esp, 4*4
269 /*CFI_OFFSET cs, -2*4;*/
270 CFI_OFFSET eip, -3*4
271 .endm
273 .macro RING0_PTREGS_FRAME
274 CFI_STARTPROC simple
275 CFI_SIGNAL_FRAME
276 CFI_DEF_CFA esp, PT_OLDESP-PT_EBX
277 /*CFI_OFFSET cs, PT_CS-PT_OLDESP;*/
278 CFI_OFFSET eip, PT_EIP-PT_OLDESP
279 /*CFI_OFFSET es, PT_ES-PT_OLDESP;*/
280 /*CFI_OFFSET ds, PT_DS-PT_OLDESP;*/
281 CFI_OFFSET eax, PT_EAX-PT_OLDESP
282 CFI_OFFSET ebp, PT_EBP-PT_OLDESP
283 CFI_OFFSET edi, PT_EDI-PT_OLDESP
284 CFI_OFFSET esi, PT_ESI-PT_OLDESP
285 CFI_OFFSET edx, PT_EDX-PT_OLDESP
286 CFI_OFFSET ecx, PT_ECX-PT_OLDESP
287 CFI_OFFSET ebx, PT_EBX-PT_OLDESP
288 .endm
290 ENTRY(ret_from_fork)
291 CFI_STARTPROC
292 pushl_cfi %eax
293 call schedule_tail
294 GET_THREAD_INFO(%ebp)
295 popl_cfi %eax
296 pushl_cfi $0x0202 # Reset kernel eflags
297 popfl_cfi
298 jmp syscall_exit
299 CFI_ENDPROC
300 END(ret_from_fork)
302 ENTRY(ret_from_kernel_thread)
303 CFI_STARTPROC
304 pushl_cfi %eax
305 call schedule_tail
306 GET_THREAD_INFO(%ebp)
307 popl_cfi %eax
308 pushl_cfi $0x0202 # Reset kernel eflags
309 popfl_cfi
310 movl PT_EBP(%esp),%eax
311 call *PT_EBX(%esp)
312 movl $0,PT_EAX(%esp)
313 jmp syscall_exit
314 CFI_ENDPROC
315 ENDPROC(ret_from_kernel_thread)
317 /*
318 * Interrupt exit functions should be protected against kprobes
319 */
320 .pushsection .kprobes.text, "ax"
321 /*
322 * Return to user mode is not as complex as all this looks,
323 * but we want the default path for a system call return to
324 * go as quickly as possible which is why some of this is
325 * less clear than it otherwise should be.
326 */
328 # userspace resumption stub bypassing syscall exit tracing
329 ALIGN
330 RING0_PTREGS_FRAME
331 ret_from_exception:
332 preempt_stop(CLBR_ANY)
333 ret_from_intr:
334 GET_THREAD_INFO(%ebp)
335 #ifdef CONFIG_VM86
336 movl PT_EFLAGS(%esp), %eax # mix EFLAGS and CS
337 movb PT_CS(%esp), %al
338 andl $(X86_EFLAGS_VM | SEGMENT_RPL_MASK), %eax
339 #else
340 /*
341 * We can be coming here from child spawned by kernel_thread().
342 */
343 movl PT_CS(%esp), %eax
344 andl $SEGMENT_RPL_MASK, %eax
345 #endif
346 cmpl $USER_RPL, %eax
347 jb resume_kernel # not returning to v8086 or userspace
349 ENTRY(resume_userspace)
350 LOCKDEP_SYS_EXIT
351 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
352 # setting need_resched or sigpending
353 # between sampling and the iret
354 TRACE_IRQS_OFF
355 movl TI_flags(%ebp), %ecx
356 andl $_TIF_WORK_MASK, %ecx # is there any work to be done on
357 # int/exception return?
358 jne work_pending
359 jmp restore_all
360 END(ret_from_exception)
362 #ifdef CONFIG_PREEMPT
363 ENTRY(resume_kernel)
364 DISABLE_INTERRUPTS(CLBR_ANY)
365 cmpl $0,TI_preempt_count(%ebp) # non-zero preempt_count ?
366 jnz restore_all
367 need_resched:
368 movl TI_flags(%ebp), %ecx # need_resched set ?
369 testb $_TIF_NEED_RESCHED, %cl
370 jz restore_all
371 testl $X86_EFLAGS_IF,PT_EFLAGS(%esp) # interrupts off (exception path) ?
372 jz restore_all
373 call preempt_schedule_irq
374 jmp need_resched
375 END(resume_kernel)
376 #endif
377 CFI_ENDPROC
378 /*
379 * End of kprobes section
380 */
381 .popsection
383 /* SYSENTER_RETURN points to after the "sysenter" instruction in
384 the vsyscall page. See vsyscall-sysentry.S, which defines the symbol. */
386 # sysenter call handler stub
387 ENTRY(ia32_sysenter_target)
388 CFI_STARTPROC simple
389 CFI_SIGNAL_FRAME
390 CFI_DEF_CFA esp, 0
391 CFI_REGISTER esp, ebp
392 movl TSS_sysenter_sp0(%esp),%esp
393 sysenter_past_esp:
394 /*
395 * Interrupts are disabled here, but we can't trace it until
396 * enough kernel state to call TRACE_IRQS_OFF can be called - but
397 * we immediately enable interrupts at that point anyway.
398 */
399 pushl_cfi $__USER_DS
400 /*CFI_REL_OFFSET ss, 0*/
401 pushl_cfi %ebp
402 CFI_REL_OFFSET esp, 0
403 pushfl_cfi
404 orl $X86_EFLAGS_IF, (%esp)
405 pushl_cfi $__USER_CS
406 /*CFI_REL_OFFSET cs, 0*/
407 /*
408 * Push current_thread_info()->sysenter_return to the stack.
409 * A tiny bit of offset fixup is necessary - 4*4 means the 4 words
410 * pushed above; +8 corresponds to copy_thread's esp0 setting.
411 */
412 pushl_cfi ((TI_sysenter_return)-THREAD_SIZE+8+4*4)(%esp)
413 CFI_REL_OFFSET eip, 0
415 pushl_cfi %eax
416 SAVE_ALL
417 ENABLE_INTERRUPTS(CLBR_NONE)
419 /*
420 * Load the potential sixth argument from user stack.
421 * Careful about security.
422 */
423 cmpl $__PAGE_OFFSET-3,%ebp
424 jae syscall_fault
425 ASM_STAC
426 1: movl (%ebp),%ebp
427 ASM_CLAC
428 movl %ebp,PT_EBP(%esp)
429 _ASM_EXTABLE(1b,syscall_fault)
431 GET_THREAD_INFO(%ebp)
433 testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%ebp)
434 jnz sysenter_audit
435 sysenter_do_call:
436 cmpl $(NR_syscalls), %eax
437 jae syscall_badsys
438 call *sys_call_table(,%eax,4)
439 movl %eax,PT_EAX(%esp)
440 LOCKDEP_SYS_EXIT
441 DISABLE_INTERRUPTS(CLBR_ANY)
442 TRACE_IRQS_OFF
443 movl TI_flags(%ebp), %ecx
444 testl $_TIF_ALLWORK_MASK, %ecx
445 jne sysexit_audit
446 sysenter_exit:
447 /* if something modifies registers it must also disable sysexit */
448 movl PT_EIP(%esp), %edx
449 movl PT_OLDESP(%esp), %ecx
450 xorl %ebp,%ebp
451 TRACE_IRQS_ON
452 1: mov PT_FS(%esp), %fs
453 PTGS_TO_GS
454 ENABLE_INTERRUPTS_SYSEXIT
456 #ifdef CONFIG_AUDITSYSCALL
457 sysenter_audit:
458 testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
459 jnz syscall_trace_entry
460 addl $4,%esp
461 CFI_ADJUST_CFA_OFFSET -4
462 /* %esi already in 8(%esp) 6th arg: 4th syscall arg */
463 /* %edx already in 4(%esp) 5th arg: 3rd syscall arg */
464 /* %ecx already in 0(%esp) 4th arg: 2nd syscall arg */
465 movl %ebx,%ecx /* 3rd arg: 1st syscall arg */
466 movl %eax,%edx /* 2nd arg: syscall number */
467 movl $AUDIT_ARCH_I386,%eax /* 1st arg: audit arch */
468 call __audit_syscall_entry
469 pushl_cfi %ebx
470 movl PT_EAX(%esp),%eax /* reload syscall number */
471 jmp sysenter_do_call
473 sysexit_audit:
474 testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %ecx
475 jne syscall_exit_work
476 TRACE_IRQS_ON
477 ENABLE_INTERRUPTS(CLBR_ANY)
478 movl %eax,%edx /* second arg, syscall return value */
479 cmpl $-MAX_ERRNO,%eax /* is it an error ? */
480 setbe %al /* 1 if so, 0 if not */
481 movzbl %al,%eax /* zero-extend that */
482 call __audit_syscall_exit
483 DISABLE_INTERRUPTS(CLBR_ANY)
484 TRACE_IRQS_OFF
485 movl TI_flags(%ebp), %ecx
486 testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %ecx
487 jne syscall_exit_work
488 movl PT_EAX(%esp),%eax /* reload syscall return value */
489 jmp sysenter_exit
490 #endif
492 CFI_ENDPROC
493 .pushsection .fixup,"ax"
494 2: movl $0,PT_FS(%esp)
495 jmp 1b
496 .popsection
497 _ASM_EXTABLE(1b,2b)
498 PTGS_TO_GS_EX
499 ENDPROC(ia32_sysenter_target)
501 /*
502 * syscall stub including irq exit should be protected against kprobes
503 */
504 .pushsection .kprobes.text, "ax"
505 # system call handler stub
506 ENTRY(system_call)
507 RING0_INT_FRAME # can't unwind into user space anyway
508 ASM_CLAC
509 pushl_cfi %eax # save orig_eax
510 SAVE_ALL
511 GET_THREAD_INFO(%ebp)
512 # system call tracing in operation / emulation
513 testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%ebp)
514 jnz syscall_trace_entry
515 cmpl $(NR_syscalls), %eax
516 jae syscall_badsys
517 syscall_call:
518 call *sys_call_table(,%eax,4)
519 movl %eax,PT_EAX(%esp) # store the return value
520 syscall_exit:
521 LOCKDEP_SYS_EXIT
522 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
523 # setting need_resched or sigpending
524 # between sampling and the iret
525 TRACE_IRQS_OFF
526 movl TI_flags(%ebp), %ecx
527 testl $_TIF_ALLWORK_MASK, %ecx # current->work
528 jne syscall_exit_work
530 restore_all:
531 TRACE_IRQS_IRET
532 restore_all_notrace:
533 movl PT_EFLAGS(%esp), %eax # mix EFLAGS, SS and CS
534 # Warning: PT_OLDSS(%esp) contains the wrong/random values if we
535 # are returning to the kernel.
536 # See comments in process.c:copy_thread() for details.
537 movb PT_OLDSS(%esp), %ah
538 movb PT_CS(%esp), %al
539 andl $(X86_EFLAGS_VM | (SEGMENT_TI_MASK << 8) | SEGMENT_RPL_MASK), %eax
540 cmpl $((SEGMENT_LDT << 8) | USER_RPL), %eax
541 CFI_REMEMBER_STATE
542 je ldt_ss # returning to user-space with LDT SS
543 restore_nocheck:
544 RESTORE_REGS 4 # skip orig_eax/error_code
545 irq_return:
546 INTERRUPT_RETURN
547 .section .fixup,"ax"
548 ENTRY(iret_exc)
549 pushl $0 # no error code
550 pushl $do_iret_error
551 jmp error_code
552 .previous
553 _ASM_EXTABLE(irq_return,iret_exc)
555 CFI_RESTORE_STATE
556 ldt_ss:
557 larl PT_OLDSS(%esp), %eax
558 jnz restore_nocheck
559 testl $0x00400000, %eax # returning to 32bit stack?
560 jnz restore_nocheck # allright, normal return
562 #ifdef CONFIG_PARAVIRT
563 /*
564 * The kernel can't run on a non-flat stack if paravirt mode
565 * is active. Rather than try to fixup the high bits of
566 * ESP, bypass this code entirely. This may break DOSemu
567 * and/or Wine support in a paravirt VM, although the option
568 * is still available to implement the setting of the high
569 * 16-bits in the INTERRUPT_RETURN paravirt-op.
570 */
571 cmpl $0, pv_info+PARAVIRT_enabled
572 jne restore_nocheck
573 #endif
575 /*
576 * Setup and switch to ESPFIX stack
577 *
578 * We're returning to userspace with a 16 bit stack. The CPU will not
579 * restore the high word of ESP for us on executing iret... This is an
580 * "official" bug of all the x86-compatible CPUs, which we can work
581 * around to make dosemu and wine happy. We do this by preloading the
582 * high word of ESP with the high word of the userspace ESP while
583 * compensating for the offset by changing to the ESPFIX segment with
584 * a base address that matches for the difference.
585 */
586 #define GDT_ESPFIX_SS PER_CPU_VAR(gdt_page) + (GDT_ENTRY_ESPFIX_SS * 8)
587 mov %esp, %edx /* load kernel esp */
588 mov PT_OLDESP(%esp), %eax /* load userspace esp */
589 mov %dx, %ax /* eax: new kernel esp */
590 sub %eax, %edx /* offset (low word is 0) */
591 shr $16, %edx
592 mov %dl, GDT_ESPFIX_SS + 4 /* bits 16..23 */
593 mov %dh, GDT_ESPFIX_SS + 7 /* bits 24..31 */
594 pushl_cfi $__ESPFIX_SS
595 pushl_cfi %eax /* new kernel esp */
596 /* Disable interrupts, but do not irqtrace this section: we
597 * will soon execute iret and the tracer was already set to
598 * the irqstate after the iret */
599 DISABLE_INTERRUPTS(CLBR_EAX)
600 lss (%esp), %esp /* switch to espfix segment */
601 CFI_ADJUST_CFA_OFFSET -8
602 jmp restore_nocheck
603 CFI_ENDPROC
604 ENDPROC(system_call)
606 # perform work that needs to be done immediately before resumption
607 ALIGN
608 RING0_PTREGS_FRAME # can't unwind into user space anyway
609 work_pending:
610 testb $_TIF_NEED_RESCHED, %cl
611 jz work_notifysig
612 work_resched:
613 call schedule
614 LOCKDEP_SYS_EXIT
615 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
616 # setting need_resched or sigpending
617 # between sampling and the iret
618 TRACE_IRQS_OFF
619 movl TI_flags(%ebp), %ecx
620 andl $_TIF_WORK_MASK, %ecx # is there any work to be done other
621 # than syscall tracing?
622 jz restore_all
623 testb $_TIF_NEED_RESCHED, %cl
624 jnz work_resched
626 work_notifysig: # deal with pending signals and
627 # notify-resume requests
628 #ifdef CONFIG_VM86
629 testl $X86_EFLAGS_VM, PT_EFLAGS(%esp)
630 movl %esp, %eax
631 jne work_notifysig_v86 # returning to kernel-space or
632 # vm86-space
633 1:
634 #else
635 movl %esp, %eax
636 #endif
637 TRACE_IRQS_ON
638 ENABLE_INTERRUPTS(CLBR_NONE)
639 movb PT_CS(%esp), %bl
640 andb $SEGMENT_RPL_MASK, %bl
641 cmpb $USER_RPL, %bl
642 jb resume_kernel
643 xorl %edx, %edx
644 call do_notify_resume
645 jmp resume_userspace
647 #ifdef CONFIG_VM86
648 ALIGN
649 work_notifysig_v86:
650 pushl_cfi %ecx # save ti_flags for do_notify_resume
651 call save_v86_state # %eax contains pt_regs pointer
652 popl_cfi %ecx
653 movl %eax, %esp
654 jmp 1b
655 #endif
656 END(work_pending)
658 # perform syscall exit tracing
659 ALIGN
660 syscall_trace_entry:
661 movl $-ENOSYS,PT_EAX(%esp)
662 movl %esp, %eax
663 call syscall_trace_enter
664 /* What it returned is what we'll actually use. */
665 cmpl $(NR_syscalls), %eax
666 jnae syscall_call
667 jmp syscall_exit
668 END(syscall_trace_entry)
670 # perform syscall exit tracing
671 ALIGN
672 syscall_exit_work:
673 testl $_TIF_WORK_SYSCALL_EXIT, %ecx
674 jz work_pending
675 TRACE_IRQS_ON
676 ENABLE_INTERRUPTS(CLBR_ANY) # could let syscall_trace_leave() call
677 # schedule() instead
678 movl %esp, %eax
679 call syscall_trace_leave
680 jmp resume_userspace
681 END(syscall_exit_work)
682 CFI_ENDPROC
684 RING0_INT_FRAME # can't unwind into user space anyway
685 syscall_fault:
686 ASM_CLAC
687 GET_THREAD_INFO(%ebp)
688 movl $-EFAULT,PT_EAX(%esp)
689 jmp resume_userspace
690 END(syscall_fault)
692 syscall_badsys:
693 movl $-ENOSYS,PT_EAX(%esp)
694 jmp resume_userspace
695 END(syscall_badsys)
696 CFI_ENDPROC
697 /*
698 * End of kprobes section
699 */
700 .popsection
702 /*
703 * System calls that need a pt_regs pointer.
704 */
705 #define PTREGSCALL0(name) \
706 ENTRY(ptregs_##name) ; \
707 leal 4(%esp),%eax; \
708 jmp sys_##name; \
709 ENDPROC(ptregs_##name)
711 #define PTREGSCALL1(name) \
712 ENTRY(ptregs_##name) ; \
713 leal 4(%esp),%edx; \
714 movl (PT_EBX+4)(%esp),%eax; \
715 jmp sys_##name; \
716 ENDPROC(ptregs_##name)
718 #define PTREGSCALL2(name) \
719 ENTRY(ptregs_##name) ; \
720 leal 4(%esp),%ecx; \
721 movl (PT_ECX+4)(%esp),%edx; \
722 movl (PT_EBX+4)(%esp),%eax; \
723 jmp sys_##name; \
724 ENDPROC(ptregs_##name)
726 #define PTREGSCALL3(name) \
727 ENTRY(ptregs_##name) ; \
728 CFI_STARTPROC; \
729 leal 4(%esp),%eax; \
730 pushl_cfi %eax; \
731 movl PT_EDX(%eax),%ecx; \
732 movl PT_ECX(%eax),%edx; \
733 movl PT_EBX(%eax),%eax; \
734 call sys_##name; \
735 addl $4,%esp; \
736 CFI_ADJUST_CFA_OFFSET -4; \
737 ret; \
738 CFI_ENDPROC; \
739 ENDPROC(ptregs_##name)
741 PTREGSCALL1(iopl)
742 PTREGSCALL0(sigreturn)
743 PTREGSCALL0(rt_sigreturn)
744 PTREGSCALL2(vm86)
745 PTREGSCALL1(vm86old)
747 .macro FIXUP_ESPFIX_STACK
748 /*
749 * Switch back for ESPFIX stack to the normal zerobased stack
750 *
751 * We can't call C functions using the ESPFIX stack. This code reads
752 * the high word of the segment base from the GDT and swiches to the
753 * normal stack and adjusts ESP with the matching offset.
754 */
755 /* fixup the stack */
756 mov GDT_ESPFIX_SS + 4, %al /* bits 16..23 */
757 mov GDT_ESPFIX_SS + 7, %ah /* bits 24..31 */
758 shl $16, %eax
759 addl %esp, %eax /* the adjusted stack pointer */
760 pushl_cfi $__KERNEL_DS
761 pushl_cfi %eax
762 lss (%esp), %esp /* switch to the normal stack segment */
763 CFI_ADJUST_CFA_OFFSET -8
764 .endm
765 .macro UNWIND_ESPFIX_STACK
766 movl %ss, %eax
767 /* see if on espfix stack */
768 cmpw $__ESPFIX_SS, %ax
769 jne 27f
770 movl $__KERNEL_DS, %eax
771 movl %eax, %ds
772 movl %eax, %es
773 /* switch to normal stack */
774 FIXUP_ESPFIX_STACK
775 27:
776 .endm
778 /*
779 * Build the entry stubs and pointer table with some assembler magic.
780 * We pack 7 stubs into a single 32-byte chunk, which will fit in a
781 * single cache line on all modern x86 implementations.
782 */
783 .section .init.rodata,"a"
784 ENTRY(interrupt)
785 .section .entry.text, "ax"
786 .p2align 5
787 .p2align CONFIG_X86_L1_CACHE_SHIFT
788 ENTRY(irq_entries_start)
789 RING0_INT_FRAME
790 vector=FIRST_EXTERNAL_VECTOR
791 .rept (NR_VECTORS-FIRST_EXTERNAL_VECTOR+6)/7
792 .balign 32
793 .rept 7
794 .if vector < NR_VECTORS
795 .if vector <> FIRST_EXTERNAL_VECTOR
796 CFI_ADJUST_CFA_OFFSET -4
797 .endif
798 1: pushl_cfi $(~vector+0x80) /* Note: always in signed byte range */
799 .if ((vector-FIRST_EXTERNAL_VECTOR)%7) <> 6
800 jmp 2f
801 .endif
802 .previous
803 .long 1b
804 .section .entry.text, "ax"
805 vector=vector+1
806 .endif
807 .endr
808 2: jmp common_interrupt
809 .endr
810 END(irq_entries_start)
812 .previous
813 END(interrupt)
814 .previous
816 /*
817 * the CPU automatically disables interrupts when executing an IRQ vector,
818 * so IRQ-flags tracing has to follow that:
819 */
820 .p2align CONFIG_X86_L1_CACHE_SHIFT
821 common_interrupt:
822 ASM_CLAC
823 addl $-0x80,(%esp) /* Adjust vector into the [-256,-1] range */
824 SAVE_ALL
825 TRACE_IRQS_OFF
826 movl %esp,%eax
827 call do_IRQ
828 jmp ret_from_intr
829 ENDPROC(common_interrupt)
830 CFI_ENDPROC
832 /*
833 * Irq entries should be protected against kprobes
834 */
835 .pushsection .kprobes.text, "ax"
836 #define BUILD_INTERRUPT3(name, nr, fn) \
837 ENTRY(name) \
838 RING0_INT_FRAME; \
839 ASM_CLAC; \
840 pushl_cfi $~(nr); \
841 SAVE_ALL; \
842 TRACE_IRQS_OFF \
843 movl %esp,%eax; \
844 call fn; \
845 jmp ret_from_intr; \
846 CFI_ENDPROC; \
847 ENDPROC(name)
849 #define BUILD_INTERRUPT(name, nr) BUILD_INTERRUPT3(name, nr, smp_##name)
851 /* The include is where all of the SMP etc. interrupts come from */
852 #include <asm/entry_arch.h>
854 ENTRY(coprocessor_error)
855 RING0_INT_FRAME
856 ASM_CLAC
857 pushl_cfi $0
858 pushl_cfi $do_coprocessor_error
859 jmp error_code
860 CFI_ENDPROC
861 END(coprocessor_error)
863 ENTRY(simd_coprocessor_error)
864 RING0_INT_FRAME
865 ASM_CLAC
866 pushl_cfi $0
867 #ifdef CONFIG_X86_INVD_BUG
868 /* AMD 486 bug: invd from userspace calls exception 19 instead of #GP */
869 661: pushl_cfi $do_general_protection
870 662:
871 .section .altinstructions,"a"
872 altinstruction_entry 661b, 663f, X86_FEATURE_XMM, 662b-661b, 664f-663f
873 .previous
874 .section .altinstr_replacement,"ax"
875 663: pushl $do_simd_coprocessor_error
876 664:
877 .previous
878 #else
879 pushl_cfi $do_simd_coprocessor_error
880 #endif
881 jmp error_code
882 CFI_ENDPROC
883 END(simd_coprocessor_error)
885 ENTRY(device_not_available)
886 RING0_INT_FRAME
887 ASM_CLAC
888 pushl_cfi $-1 # mark this as an int
889 pushl_cfi $do_device_not_available
890 jmp error_code
891 CFI_ENDPROC
892 END(device_not_available)
894 #ifdef CONFIG_PARAVIRT
895 ENTRY(native_iret)
896 iret
897 _ASM_EXTABLE(native_iret, iret_exc)
898 END(native_iret)
900 ENTRY(native_irq_enable_sysexit)
901 sti
902 sysexit
903 END(native_irq_enable_sysexit)
904 #endif
906 ENTRY(overflow)
907 RING0_INT_FRAME
908 ASM_CLAC
909 pushl_cfi $0
910 pushl_cfi $do_overflow
911 jmp error_code
912 CFI_ENDPROC
913 END(overflow)
915 ENTRY(bounds)
916 RING0_INT_FRAME
917 ASM_CLAC
918 pushl_cfi $0
919 pushl_cfi $do_bounds
920 jmp error_code
921 CFI_ENDPROC
922 END(bounds)
924 ENTRY(invalid_op)
925 RING0_INT_FRAME
926 ASM_CLAC
927 pushl_cfi $0
928 pushl_cfi $do_invalid_op
929 jmp error_code
930 CFI_ENDPROC
931 END(invalid_op)
933 ENTRY(coprocessor_segment_overrun)
934 RING0_INT_FRAME
935 ASM_CLAC
936 pushl_cfi $0
937 pushl_cfi $do_coprocessor_segment_overrun
938 jmp error_code
939 CFI_ENDPROC
940 END(coprocessor_segment_overrun)
942 ENTRY(invalid_TSS)
943 RING0_EC_FRAME
944 ASM_CLAC
945 pushl_cfi $do_invalid_TSS
946 jmp error_code
947 CFI_ENDPROC
948 END(invalid_TSS)
950 ENTRY(segment_not_present)
951 RING0_EC_FRAME
952 ASM_CLAC
953 pushl_cfi $do_segment_not_present
954 jmp error_code
955 CFI_ENDPROC
956 END(segment_not_present)
958 ENTRY(stack_segment)
959 RING0_EC_FRAME
960 ASM_CLAC
961 pushl_cfi $do_stack_segment
962 jmp error_code
963 CFI_ENDPROC
964 END(stack_segment)
966 ENTRY(alignment_check)
967 RING0_EC_FRAME
968 ASM_CLAC
969 pushl_cfi $do_alignment_check
970 jmp error_code
971 CFI_ENDPROC
972 END(alignment_check)
974 ENTRY(divide_error)
975 RING0_INT_FRAME
976 ASM_CLAC
977 pushl_cfi $0 # no error code
978 pushl_cfi $do_divide_error
979 jmp error_code
980 CFI_ENDPROC
981 END(divide_error)
983 #ifdef CONFIG_X86_MCE
984 ENTRY(machine_check)
985 RING0_INT_FRAME
986 ASM_CLAC
987 pushl_cfi $0
988 pushl_cfi machine_check_vector
989 jmp error_code
990 CFI_ENDPROC
991 END(machine_check)
992 #endif
994 ENTRY(spurious_interrupt_bug)
995 RING0_INT_FRAME
996 ASM_CLAC
997 pushl_cfi $0
998 pushl_cfi $do_spurious_interrupt_bug
999 jmp error_code
1000 CFI_ENDPROC
1001 END(spurious_interrupt_bug)
1002 /*
1003 * End of kprobes section
1004 */
1005 .popsection
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. */
1010 ENTRY(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
1017 ENTRY(xen_hypervisor_callback)
1018 CFI_STARTPROC
1019 pushl_cfi $-1 /* orig_ax = -1 => not a system call */
1020 SAVE_ALL
1021 TRACE_IRQS_OFF
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
1034 jmp xen_iret_crit_fixup
1036 ENTRY(xen_do_upcall)
1037 1: mov %esp, %eax
1038 call xen_evtchn_do_upcall
1039 jmp ret_from_intr
1040 CFI_ENDPROC
1041 ENDPROC(xen_hypervisor_callback)
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.
1053 ENTRY(xen_failsafe_callback)
1054 CFI_STARTPROC
1055 pushl_cfi %eax
1056 movl $1,%eax
1057 1: mov 4(%esp),%ds
1058 2: mov 8(%esp),%es
1059 3: mov 12(%esp),%fs
1060 4: mov 16(%esp),%gs
1061 /* EAX == 0 => Category 1 (Bad segment)
1062 EAX != 0 => Category 2 (Bad IRET) */
1063 testl %eax,%eax
1064 popl_cfi %eax
1065 lea 16(%esp),%esp
1066 CFI_ADJUST_CFA_OFFSET -16
1067 jz 5f
1068 jmp iret_exc
1069 5: pushl_cfi $-1 /* orig_ax = -1 => not a system call */
1070 SAVE_ALL
1071 jmp ret_from_exception
1072 CFI_ENDPROC
1074 .section .fixup,"ax"
1075 6: xorl %eax,%eax
1076 movl %eax,4(%esp)
1077 jmp 1b
1078 7: xorl %eax,%eax
1079 movl %eax,8(%esp)
1080 jmp 2b
1081 8: xorl %eax,%eax
1082 movl %eax,12(%esp)
1083 jmp 3b
1084 9: xorl %eax,%eax
1085 movl %eax,16(%esp)
1086 jmp 4b
1087 .previous
1088 _ASM_EXTABLE(1b,6b)
1089 _ASM_EXTABLE(2b,7b)
1090 _ASM_EXTABLE(3b,8b)
1091 _ASM_EXTABLE(4b,9b)
1092 ENDPROC(xen_failsafe_callback)
1094 BUILD_INTERRUPT3(xen_hvm_callback_vector, XEN_HVM_EVTCHN_CALLBACK,
1095 xen_evtchn_do_upcall)
1097 #endif /* CONFIG_XEN */
1099 #ifdef CONFIG_FUNCTION_TRACER
1100 #ifdef CONFIG_DYNAMIC_FTRACE
1102 ENTRY(mcount)
1103 ret
1104 END(mcount)
1106 ENTRY(ftrace_caller)
1107 cmpl $0, function_trace_stop
1108 jne ftrace_stub
1110 pushl %eax
1111 pushl %ecx
1112 pushl %edx
1113 pushl $0 /* Pass NULL as regs pointer */
1114 movl 4*4(%esp), %eax
1115 movl 0x4(%ebp), %edx
1116 leal function_trace_op, %ecx
1117 subl $MCOUNT_INSN_SIZE, %eax
1119 .globl ftrace_call
1120 ftrace_call:
1121 call ftrace_stub
1123 addl $4,%esp /* skip NULL pointer */
1124 popl %edx
1125 popl %ecx
1126 popl %eax
1127 ftrace_ret:
1128 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1129 .globl ftrace_graph_call
1130 ftrace_graph_call:
1131 jmp ftrace_stub
1132 #endif
1134 .globl ftrace_stub
1135 ftrace_stub:
1136 ret
1137 END(ftrace_caller)
1139 ENTRY(ftrace_regs_caller)
1140 pushf /* push flags before compare (in cs location) */
1141 cmpl $0, function_trace_stop
1142 jne ftrace_restore_flags
1144 /*
1145 * i386 does not save SS and ESP when coming from kernel.
1146 * Instead, to get sp, ®s->sp is used (see ptrace.h).
1147 * Unfortunately, that means eflags must be at the same location
1148 * as the current return ip is. We move the return ip into the
1149 * ip location, and move flags into the return ip location.
1150 */
1151 pushl 4(%esp) /* save return ip into ip slot */
1153 pushl $0 /* Load 0 into orig_ax */
1154 pushl %gs
1155 pushl %fs
1156 pushl %es
1157 pushl %ds
1158 pushl %eax
1159 pushl %ebp
1160 pushl %edi
1161 pushl %esi
1162 pushl %edx
1163 pushl %ecx
1164 pushl %ebx
1166 movl 13*4(%esp), %eax /* Get the saved flags */
1167 movl %eax, 14*4(%esp) /* Move saved flags into regs->flags location */
1168 /* clobbering return ip */
1169 movl $__KERNEL_CS,13*4(%esp)
1171 movl 12*4(%esp), %eax /* Load ip (1st parameter) */
1172 subl $MCOUNT_INSN_SIZE, %eax /* Adjust ip */
1173 movl 0x4(%ebp), %edx /* Load parent ip (2nd parameter) */
1174 leal function_trace_op, %ecx /* Save ftrace_pos in 3rd parameter */
1175 pushl %esp /* Save pt_regs as 4th parameter */
1177 GLOBAL(ftrace_regs_call)
1178 call ftrace_stub
1180 addl $4, %esp /* Skip pt_regs */
1181 movl 14*4(%esp), %eax /* Move flags back into cs */
1182 movl %eax, 13*4(%esp) /* Needed to keep addl from modifying flags */
1183 movl 12*4(%esp), %eax /* Get return ip from regs->ip */
1184 movl %eax, 14*4(%esp) /* Put return ip back for ret */
1186 popl %ebx
1187 popl %ecx
1188 popl %edx
1189 popl %esi
1190 popl %edi
1191 popl %ebp
1192 popl %eax
1193 popl %ds
1194 popl %es
1195 popl %fs
1196 popl %gs
1197 addl $8, %esp /* Skip orig_ax and ip */
1198 popf /* Pop flags at end (no addl to corrupt flags) */
1199 jmp ftrace_ret
1201 ftrace_restore_flags:
1202 popf
1203 jmp ftrace_stub
1204 #else /* ! CONFIG_DYNAMIC_FTRACE */
1206 ENTRY(mcount)
1207 cmpl $0, function_trace_stop
1208 jne ftrace_stub
1210 cmpl $ftrace_stub, ftrace_trace_function
1211 jnz trace
1212 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1213 cmpl $ftrace_stub, ftrace_graph_return
1214 jnz ftrace_graph_caller
1216 cmpl $ftrace_graph_entry_stub, ftrace_graph_entry
1217 jnz ftrace_graph_caller
1218 #endif
1219 .globl ftrace_stub
1220 ftrace_stub:
1221 ret
1223 /* taken from glibc */
1224 trace:
1225 pushl %eax
1226 pushl %ecx
1227 pushl %edx
1228 movl 0xc(%esp), %eax
1229 movl 0x4(%ebp), %edx
1230 subl $MCOUNT_INSN_SIZE, %eax
1232 call *ftrace_trace_function
1234 popl %edx
1235 popl %ecx
1236 popl %eax
1237 jmp ftrace_stub
1238 END(mcount)
1239 #endif /* CONFIG_DYNAMIC_FTRACE */
1240 #endif /* CONFIG_FUNCTION_TRACER */
1242 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1243 ENTRY(ftrace_graph_caller)
1244 pushl %eax
1245 pushl %ecx
1246 pushl %edx
1247 movl 0xc(%esp), %edx
1248 lea 0x4(%ebp), %eax
1249 movl (%ebp), %ecx
1250 subl $MCOUNT_INSN_SIZE, %edx
1251 call prepare_ftrace_return
1252 popl %edx
1253 popl %ecx
1254 popl %eax
1255 ret
1256 END(ftrace_graph_caller)
1258 .globl return_to_handler
1259 return_to_handler:
1260 pushl %eax
1261 pushl %edx
1262 movl %ebp, %eax
1263 call ftrace_return_to_handler
1264 movl %eax, %ecx
1265 popl %edx
1266 popl %eax
1267 jmp *%ecx
1268 #endif
1270 /*
1271 * Some functions should be protected against kprobes
1272 */
1273 .pushsection .kprobes.text, "ax"
1275 ENTRY(page_fault)
1276 RING0_EC_FRAME
1277 ASM_CLAC
1278 pushl_cfi $do_page_fault
1279 ALIGN
1280 error_code:
1281 /* the function address is in %gs's slot on the stack */
1282 pushl_cfi %fs
1283 /*CFI_REL_OFFSET fs, 0*/
1284 pushl_cfi %es
1285 /*CFI_REL_OFFSET es, 0*/
1286 pushl_cfi %ds
1287 /*CFI_REL_OFFSET ds, 0*/
1288 pushl_cfi %eax
1289 CFI_REL_OFFSET eax, 0
1290 pushl_cfi %ebp
1291 CFI_REL_OFFSET ebp, 0
1292 pushl_cfi %edi
1293 CFI_REL_OFFSET edi, 0
1294 pushl_cfi %esi
1295 CFI_REL_OFFSET esi, 0
1296 pushl_cfi %edx
1297 CFI_REL_OFFSET edx, 0
1298 pushl_cfi %ecx
1299 CFI_REL_OFFSET ecx, 0
1300 pushl_cfi %ebx
1301 CFI_REL_OFFSET ebx, 0
1302 cld
1303 movl $(__KERNEL_PERCPU), %ecx
1304 movl %ecx, %fs
1305 UNWIND_ESPFIX_STACK
1306 GS_TO_REG %ecx
1307 movl PT_GS(%esp), %edi # get the function address
1308 movl PT_ORIG_EAX(%esp), %edx # get the error code
1309 movl $-1, PT_ORIG_EAX(%esp) # no syscall to restart
1310 REG_TO_PTGS %ecx
1311 SET_KERNEL_GS %ecx
1312 movl $(__USER_DS), %ecx
1313 movl %ecx, %ds
1314 movl %ecx, %es
1315 TRACE_IRQS_OFF
1316 movl %esp,%eax # pt_regs pointer
1317 call *%edi
1318 jmp ret_from_exception
1319 CFI_ENDPROC
1320 END(page_fault)
1322 /*
1323 * Debug traps and NMI can happen at the one SYSENTER instruction
1324 * that sets up the real kernel stack. Check here, since we can't
1325 * allow the wrong stack to be used.
1326 *
1327 * "TSS_sysenter_sp0+12" is because the NMI/debug handler will have
1328 * already pushed 3 words if it hits on the sysenter instruction:
1329 * eflags, cs and eip.
1330 *
1331 * We just load the right stack, and push the three (known) values
1332 * by hand onto the new stack - while updating the return eip past
1333 * the instruction that would have done it for sysenter.
1334 */
1335 .macro FIX_STACK offset ok label
1336 cmpw $__KERNEL_CS, 4(%esp)
1337 jne \ok
1338 \label:
1339 movl TSS_sysenter_sp0 + \offset(%esp), %esp
1340 CFI_DEF_CFA esp, 0
1341 CFI_UNDEFINED eip
1342 pushfl_cfi
1343 pushl_cfi $__KERNEL_CS
1344 pushl_cfi $sysenter_past_esp
1345 CFI_REL_OFFSET eip, 0
1346 .endm
1348 ENTRY(debug)
1349 RING0_INT_FRAME
1350 ASM_CLAC
1351 cmpl $ia32_sysenter_target,(%esp)
1352 jne debug_stack_correct
1353 FIX_STACK 12, debug_stack_correct, debug_esp_fix_insn
1354 debug_stack_correct:
1355 pushl_cfi $-1 # mark this as an int
1356 SAVE_ALL
1357 TRACE_IRQS_OFF
1358 xorl %edx,%edx # error code 0
1359 movl %esp,%eax # pt_regs pointer
1360 call do_debug
1361 jmp ret_from_exception
1362 CFI_ENDPROC
1363 END(debug)
1365 /*
1366 * NMI is doubly nasty. It can happen _while_ we're handling
1367 * a debug fault, and the debug fault hasn't yet been able to
1368 * clear up the stack. So we first check whether we got an
1369 * NMI on the sysenter entry path, but after that we need to
1370 * check whether we got an NMI on the debug path where the debug
1371 * fault happened on the sysenter path.
1372 */
1373 ENTRY(nmi)
1374 RING0_INT_FRAME
1375 ASM_CLAC
1376 pushl_cfi %eax
1377 movl %ss, %eax
1378 cmpw $__ESPFIX_SS, %ax
1379 popl_cfi %eax
1380 je nmi_espfix_stack
1381 cmpl $ia32_sysenter_target,(%esp)
1382 je nmi_stack_fixup
1383 pushl_cfi %eax
1384 movl %esp,%eax
1385 /* Do not access memory above the end of our stack page,
1386 * it might not exist.
1387 */
1388 andl $(THREAD_SIZE-1),%eax
1389 cmpl $(THREAD_SIZE-20),%eax
1390 popl_cfi %eax
1391 jae nmi_stack_correct
1392 cmpl $ia32_sysenter_target,12(%esp)
1393 je nmi_debug_stack_check
1394 nmi_stack_correct:
1395 /* We have a RING0_INT_FRAME here */
1396 pushl_cfi %eax
1397 SAVE_ALL
1398 xorl %edx,%edx # zero error code
1399 movl %esp,%eax # pt_regs pointer
1400 call do_nmi
1401 jmp restore_all_notrace
1402 CFI_ENDPROC
1404 nmi_stack_fixup:
1405 RING0_INT_FRAME
1406 FIX_STACK 12, nmi_stack_correct, 1
1407 jmp nmi_stack_correct
1409 nmi_debug_stack_check:
1410 /* We have a RING0_INT_FRAME here */
1411 cmpw $__KERNEL_CS,16(%esp)
1412 jne nmi_stack_correct
1413 cmpl $debug,(%esp)
1414 jb nmi_stack_correct
1415 cmpl $debug_esp_fix_insn,(%esp)
1416 ja nmi_stack_correct
1417 FIX_STACK 24, nmi_stack_correct, 1
1418 jmp nmi_stack_correct
1420 nmi_espfix_stack:
1421 /* We have a RING0_INT_FRAME here.
1422 *
1423 * create the pointer to lss back
1424 */
1425 pushl_cfi %ss
1426 pushl_cfi %esp
1427 addl $4, (%esp)
1428 /* copy the iret frame of 12 bytes */
1429 .rept 3
1430 pushl_cfi 16(%esp)
1431 .endr
1432 pushl_cfi %eax
1433 SAVE_ALL
1434 FIXUP_ESPFIX_STACK # %eax == %esp
1435 xorl %edx,%edx # zero error code
1436 call do_nmi
1437 RESTORE_REGS
1438 lss 12+4(%esp), %esp # back to espfix stack
1439 CFI_ADJUST_CFA_OFFSET -24
1440 jmp irq_return
1441 CFI_ENDPROC
1442 END(nmi)
1444 ENTRY(int3)
1445 RING0_INT_FRAME
1446 ASM_CLAC
1447 pushl_cfi $-1 # mark this as an int
1448 SAVE_ALL
1449 TRACE_IRQS_OFF
1450 xorl %edx,%edx # zero error code
1451 movl %esp,%eax # pt_regs pointer
1452 call do_int3
1453 jmp ret_from_exception
1454 CFI_ENDPROC
1455 END(int3)
1457 ENTRY(general_protection)
1458 RING0_EC_FRAME
1459 pushl_cfi $do_general_protection
1460 jmp error_code
1461 CFI_ENDPROC
1462 END(general_protection)
1464 #ifdef CONFIG_KVM_GUEST
1465 ENTRY(async_page_fault)
1466 RING0_EC_FRAME
1467 ASM_CLAC
1468 pushl_cfi $do_async_page_fault
1469 jmp error_code
1470 CFI_ENDPROC
1471 END(async_page_fault)
1472 #endif
1474 /*
1475 * End of kprobes section
1476 */
1477 .popsection