| blob | cd49141cf153fb124dc46a6497dbc863a3c81ad9 |
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>
56 #include <asm/cpufeature.h>
58 /* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */
59 #include <linux/elf-em.h>
60 #define AUDIT_ARCH_I386 (EM_386|__AUDIT_ARCH_LE)
61 #define __AUDIT_ARCH_LE 0x40000000
63 #ifndef CONFIG_AUDITSYSCALL
64 #define sysenter_audit syscall_trace_entry
65 #define sysexit_audit syscall_exit_work
66 #endif
68 /*
69 * We use macros for low-level operations which need to be overridden
70 * for paravirtualization. The following will never clobber any registers:
71 * INTERRUPT_RETURN (aka. "iret")
72 * GET_CR0_INTO_EAX (aka. "movl %cr0, %eax")
73 * ENABLE_INTERRUPTS_SYSEXIT (aka "sti; sysexit").
74 *
75 * For DISABLE_INTERRUPTS/ENABLE_INTERRUPTS (aka "cli"/"sti"), you must
76 * specify what registers can be overwritten (CLBR_NONE, CLBR_EAX/EDX/ECX/ANY).
77 * Allowing a register to be clobbered can shrink the paravirt replacement
78 * enough to patch inline, increasing performance.
79 */
81 #define nr_syscalls ((syscall_table_size)/4)
83 #ifdef CONFIG_PREEMPT
84 #define preempt_stop(clobbers) DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF
85 #else
86 #define preempt_stop(clobbers)
87 #define resume_kernel restore_all
88 #endif
90 .macro TRACE_IRQS_IRET
91 #ifdef CONFIG_TRACE_IRQFLAGS
92 testl $X86_EFLAGS_IF,PT_EFLAGS(%esp) # interrupts off?
93 jz 1f
94 TRACE_IRQS_ON
95 1:
96 #endif
97 .endm
99 #ifdef CONFIG_VM86
100 #define resume_userspace_sig check_userspace
101 #else
102 #define resume_userspace_sig resume_userspace
103 #endif
105 /*
106 * User gs save/restore
107 *
108 * %gs is used for userland TLS and kernel only uses it for stack
109 * canary which is required to be at %gs:20 by gcc. Read the comment
110 * at the top of stackprotector.h for more info.
111 *
112 * Local labels 98 and 99 are used.
113 */
114 #ifdef CONFIG_X86_32_LAZY_GS
116 /* unfortunately push/pop can't be no-op */
117 .macro PUSH_GS
118 pushl $0
119 CFI_ADJUST_CFA_OFFSET 4
120 .endm
121 .macro POP_GS pop=0
122 addl $(4 + \pop), %esp
123 CFI_ADJUST_CFA_OFFSET -(4 + \pop)
124 .endm
125 .macro POP_GS_EX
126 .endm
128 /* all the rest are no-op */
129 .macro PTGS_TO_GS
130 .endm
131 .macro PTGS_TO_GS_EX
132 .endm
133 .macro GS_TO_REG reg
134 .endm
135 .macro REG_TO_PTGS reg
136 .endm
137 .macro SET_KERNEL_GS reg
138 .endm
140 #else /* CONFIG_X86_32_LAZY_GS */
142 .macro PUSH_GS
143 pushl %gs
144 CFI_ADJUST_CFA_OFFSET 4
145 /*CFI_REL_OFFSET gs, 0*/
146 .endm
148 .macro POP_GS pop=0
149 98: popl %gs
150 CFI_ADJUST_CFA_OFFSET -4
151 /*CFI_RESTORE gs*/
152 .if \pop <> 0
153 add $\pop, %esp
154 CFI_ADJUST_CFA_OFFSET -\pop
155 .endif
156 .endm
157 .macro POP_GS_EX
158 .pushsection .fixup, "ax"
159 99: movl $0, (%esp)
160 jmp 98b
161 .section __ex_table, "a"
162 .align 4
163 .long 98b, 99b
164 .popsection
165 .endm
167 .macro PTGS_TO_GS
168 98: mov PT_GS(%esp), %gs
169 .endm
170 .macro PTGS_TO_GS_EX
171 .pushsection .fixup, "ax"
172 99: movl $0, PT_GS(%esp)
173 jmp 98b
174 .section __ex_table, "a"
175 .align 4
176 .long 98b, 99b
177 .popsection
178 .endm
180 .macro GS_TO_REG reg
181 movl %gs, \reg
182 /*CFI_REGISTER gs, \reg*/
183 .endm
184 .macro REG_TO_PTGS reg
185 movl \reg, PT_GS(%esp)
186 /*CFI_REL_OFFSET gs, PT_GS*/
187 .endm
188 .macro SET_KERNEL_GS reg
189 movl $(__KERNEL_STACK_CANARY), \reg
190 movl \reg, %gs
191 .endm
193 #endif /* CONFIG_X86_32_LAZY_GS */
195 .macro SAVE_ALL
196 cld
197 PUSH_GS
198 pushl %fs
199 CFI_ADJUST_CFA_OFFSET 4
200 /*CFI_REL_OFFSET fs, 0;*/
201 pushl %es
202 CFI_ADJUST_CFA_OFFSET 4
203 /*CFI_REL_OFFSET es, 0;*/
204 pushl %ds
205 CFI_ADJUST_CFA_OFFSET 4
206 /*CFI_REL_OFFSET ds, 0;*/
207 pushl %eax
208 CFI_ADJUST_CFA_OFFSET 4
209 CFI_REL_OFFSET eax, 0
210 pushl %ebp
211 CFI_ADJUST_CFA_OFFSET 4
212 CFI_REL_OFFSET ebp, 0
213 pushl %edi
214 CFI_ADJUST_CFA_OFFSET 4
215 CFI_REL_OFFSET edi, 0
216 pushl %esi
217 CFI_ADJUST_CFA_OFFSET 4
218 CFI_REL_OFFSET esi, 0
219 pushl %edx
220 CFI_ADJUST_CFA_OFFSET 4
221 CFI_REL_OFFSET edx, 0
222 pushl %ecx
223 CFI_ADJUST_CFA_OFFSET 4
224 CFI_REL_OFFSET ecx, 0
225 pushl %ebx
226 CFI_ADJUST_CFA_OFFSET 4
227 CFI_REL_OFFSET ebx, 0
228 movl $(__USER_DS), %edx
229 movl %edx, %ds
230 movl %edx, %es
231 movl $(__KERNEL_PERCPU), %edx
232 movl %edx, %fs
233 SET_KERNEL_GS %edx
234 .endm
236 .macro RESTORE_INT_REGS
237 popl %ebx
238 CFI_ADJUST_CFA_OFFSET -4
239 CFI_RESTORE ebx
240 popl %ecx
241 CFI_ADJUST_CFA_OFFSET -4
242 CFI_RESTORE ecx
243 popl %edx
244 CFI_ADJUST_CFA_OFFSET -4
245 CFI_RESTORE edx
246 popl %esi
247 CFI_ADJUST_CFA_OFFSET -4
248 CFI_RESTORE esi
249 popl %edi
250 CFI_ADJUST_CFA_OFFSET -4
251 CFI_RESTORE edi
252 popl %ebp
253 CFI_ADJUST_CFA_OFFSET -4
254 CFI_RESTORE ebp
255 popl %eax
256 CFI_ADJUST_CFA_OFFSET -4
257 CFI_RESTORE eax
258 .endm
260 .macro RESTORE_REGS pop=0
261 RESTORE_INT_REGS
262 1: popl %ds
263 CFI_ADJUST_CFA_OFFSET -4
264 /*CFI_RESTORE ds;*/
265 2: popl %es
266 CFI_ADJUST_CFA_OFFSET -4
267 /*CFI_RESTORE es;*/
268 3: popl %fs
269 CFI_ADJUST_CFA_OFFSET -4
270 /*CFI_RESTORE fs;*/
271 POP_GS \pop
272 .pushsection .fixup, "ax"
273 4: movl $0, (%esp)
274 jmp 1b
275 5: movl $0, (%esp)
276 jmp 2b
277 6: movl $0, (%esp)
278 jmp 3b
279 .section __ex_table, "a"
280 .align 4
281 .long 1b, 4b
282 .long 2b, 5b
283 .long 3b, 6b
284 .popsection
285 POP_GS_EX
286 .endm
288 .macro RING0_INT_FRAME
289 CFI_STARTPROC simple
290 CFI_SIGNAL_FRAME
291 CFI_DEF_CFA esp, 3*4
292 /*CFI_OFFSET cs, -2*4;*/
293 CFI_OFFSET eip, -3*4
294 .endm
296 .macro RING0_EC_FRAME
297 CFI_STARTPROC simple
298 CFI_SIGNAL_FRAME
299 CFI_DEF_CFA esp, 4*4
300 /*CFI_OFFSET cs, -2*4;*/
301 CFI_OFFSET eip, -3*4
302 .endm
304 .macro RING0_PTREGS_FRAME
305 CFI_STARTPROC simple
306 CFI_SIGNAL_FRAME
307 CFI_DEF_CFA esp, PT_OLDESP-PT_EBX
308 /*CFI_OFFSET cs, PT_CS-PT_OLDESP;*/
309 CFI_OFFSET eip, PT_EIP-PT_OLDESP
310 /*CFI_OFFSET es, PT_ES-PT_OLDESP;*/
311 /*CFI_OFFSET ds, PT_DS-PT_OLDESP;*/
312 CFI_OFFSET eax, PT_EAX-PT_OLDESP
313 CFI_OFFSET ebp, PT_EBP-PT_OLDESP
314 CFI_OFFSET edi, PT_EDI-PT_OLDESP
315 CFI_OFFSET esi, PT_ESI-PT_OLDESP
316 CFI_OFFSET edx, PT_EDX-PT_OLDESP
317 CFI_OFFSET ecx, PT_ECX-PT_OLDESP
318 CFI_OFFSET ebx, PT_EBX-PT_OLDESP
319 .endm
321 ENTRY(ret_from_fork)
322 CFI_STARTPROC
323 pushl %eax
324 CFI_ADJUST_CFA_OFFSET 4
325 call schedule_tail
326 GET_THREAD_INFO(%ebp)
327 popl %eax
328 CFI_ADJUST_CFA_OFFSET -4
329 pushl $0x0202 # Reset kernel eflags
330 CFI_ADJUST_CFA_OFFSET 4
331 popfl
332 CFI_ADJUST_CFA_OFFSET -4
333 jmp syscall_exit
334 CFI_ENDPROC
335 END(ret_from_fork)
337 /*
338 * Interrupt exit functions should be protected against kprobes
339 */
340 .pushsection .kprobes.text, "ax"
341 /*
342 * Return to user mode is not as complex as all this looks,
343 * but we want the default path for a system call return to
344 * go as quickly as possible which is why some of this is
345 * less clear than it otherwise should be.
346 */
348 # userspace resumption stub bypassing syscall exit tracing
349 ALIGN
350 RING0_PTREGS_FRAME
351 ret_from_exception:
352 preempt_stop(CLBR_ANY)
353 ret_from_intr:
354 GET_THREAD_INFO(%ebp)
355 check_userspace:
356 movl PT_EFLAGS(%esp), %eax # mix EFLAGS and CS
357 movb PT_CS(%esp), %al
358 andl $(X86_EFLAGS_VM | SEGMENT_RPL_MASK), %eax
359 cmpl $USER_RPL, %eax
360 jb resume_kernel # not returning to v8086 or userspace
362 ENTRY(resume_userspace)
363 LOCKDEP_SYS_EXIT
364 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
365 # setting need_resched or sigpending
366 # between sampling and the iret
367 TRACE_IRQS_OFF
368 movl TI_flags(%ebp), %ecx
369 andl $_TIF_WORK_MASK, %ecx # is there any work to be done on
370 # int/exception return?
371 jne work_pending
372 jmp restore_all
373 END(ret_from_exception)
375 #ifdef CONFIG_PREEMPT
376 ENTRY(resume_kernel)
377 DISABLE_INTERRUPTS(CLBR_ANY)
378 cmpl $0,TI_preempt_count(%ebp) # non-zero preempt_count ?
379 jnz restore_all
380 need_resched:
381 movl TI_flags(%ebp), %ecx # need_resched set ?
382 testb $_TIF_NEED_RESCHED, %cl
383 jz restore_all
384 testl $X86_EFLAGS_IF,PT_EFLAGS(%esp) # interrupts off (exception path) ?
385 jz restore_all
386 call preempt_schedule_irq
387 jmp need_resched
388 END(resume_kernel)
389 #endif
390 CFI_ENDPROC
391 /*
392 * End of kprobes section
393 */
394 .popsection
396 /* SYSENTER_RETURN points to after the "sysenter" instruction in
397 the vsyscall page. See vsyscall-sysentry.S, which defines the symbol. */
399 # sysenter call handler stub
400 ENTRY(ia32_sysenter_target)
401 CFI_STARTPROC simple
402 CFI_SIGNAL_FRAME
403 CFI_DEF_CFA esp, 0
404 CFI_REGISTER esp, ebp
405 movl TSS_sysenter_sp0(%esp),%esp
406 sysenter_past_esp:
407 /*
408 * Interrupts are disabled here, but we can't trace it until
409 * enough kernel state to call TRACE_IRQS_OFF can be called - but
410 * we immediately enable interrupts at that point anyway.
411 */
412 pushl $(__USER_DS)
413 CFI_ADJUST_CFA_OFFSET 4
414 /*CFI_REL_OFFSET ss, 0*/
415 pushl %ebp
416 CFI_ADJUST_CFA_OFFSET 4
417 CFI_REL_OFFSET esp, 0
418 pushfl
419 orl $X86_EFLAGS_IF, (%esp)
420 CFI_ADJUST_CFA_OFFSET 4
421 pushl $(__USER_CS)
422 CFI_ADJUST_CFA_OFFSET 4
423 /*CFI_REL_OFFSET cs, 0*/
424 /*
425 * Push current_thread_info()->sysenter_return to the stack.
426 * A tiny bit of offset fixup is necessary - 4*4 means the 4 words
427 * pushed above; +8 corresponds to copy_thread's esp0 setting.
428 */
429 pushl (TI_sysenter_return-THREAD_SIZE+8+4*4)(%esp)
430 CFI_ADJUST_CFA_OFFSET 4
431 CFI_REL_OFFSET eip, 0
433 pushl %eax
434 CFI_ADJUST_CFA_OFFSET 4
435 SAVE_ALL
436 ENABLE_INTERRUPTS(CLBR_NONE)
438 /*
439 * Load the potential sixth argument from user stack.
440 * Careful about security.
441 */
442 cmpl $__PAGE_OFFSET-3,%ebp
443 jae syscall_fault
444 1: movl (%ebp),%ebp
445 movl %ebp,PT_EBP(%esp)
446 .section __ex_table,"a"
447 .align 4
448 .long 1b,syscall_fault
449 .previous
451 GET_THREAD_INFO(%ebp)
453 testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%ebp)
454 jnz sysenter_audit
455 sysenter_do_call:
456 cmpl $(nr_syscalls), %eax
457 jae syscall_badsys
458 call *sys_call_table(,%eax,4)
459 movl %eax,PT_EAX(%esp)
460 LOCKDEP_SYS_EXIT
461 DISABLE_INTERRUPTS(CLBR_ANY)
462 TRACE_IRQS_OFF
463 movl TI_flags(%ebp), %ecx
464 testl $_TIF_ALLWORK_MASK, %ecx
465 jne sysexit_audit
466 sysenter_exit:
467 /* if something modifies registers it must also disable sysexit */
468 movl PT_EIP(%esp), %edx
469 movl PT_OLDESP(%esp), %ecx
470 xorl %ebp,%ebp
471 TRACE_IRQS_ON
472 1: mov PT_FS(%esp), %fs
473 PTGS_TO_GS
474 ENABLE_INTERRUPTS_SYSEXIT
476 #ifdef CONFIG_AUDITSYSCALL
477 sysenter_audit:
478 testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
479 jnz syscall_trace_entry
480 addl $4,%esp
481 CFI_ADJUST_CFA_OFFSET -4
482 /* %esi already in 8(%esp) 6th arg: 4th syscall arg */
483 /* %edx already in 4(%esp) 5th arg: 3rd syscall arg */
484 /* %ecx already in 0(%esp) 4th arg: 2nd syscall arg */
485 movl %ebx,%ecx /* 3rd arg: 1st syscall arg */
486 movl %eax,%edx /* 2nd arg: syscall number */
487 movl $AUDIT_ARCH_I386,%eax /* 1st arg: audit arch */
488 call audit_syscall_entry
489 pushl %ebx
490 CFI_ADJUST_CFA_OFFSET 4
491 movl PT_EAX(%esp),%eax /* reload syscall number */
492 jmp sysenter_do_call
494 sysexit_audit:
495 testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %ecx
496 jne syscall_exit_work
497 TRACE_IRQS_ON
498 ENABLE_INTERRUPTS(CLBR_ANY)
499 movl %eax,%edx /* second arg, syscall return value */
500 cmpl $0,%eax /* is it < 0? */
501 setl %al /* 1 if so, 0 if not */
502 movzbl %al,%eax /* zero-extend that */
503 inc %eax /* first arg, 0->1(AUDITSC_SUCCESS), 1->2(AUDITSC_FAILURE) */
504 call audit_syscall_exit
505 DISABLE_INTERRUPTS(CLBR_ANY)
506 TRACE_IRQS_OFF
507 movl TI_flags(%ebp), %ecx
508 testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %ecx
509 jne syscall_exit_work
510 movl PT_EAX(%esp),%eax /* reload syscall return value */
511 jmp sysenter_exit
512 #endif
514 CFI_ENDPROC
515 .pushsection .fixup,"ax"
516 2: movl $0,PT_FS(%esp)
517 jmp 1b
518 .section __ex_table,"a"
519 .align 4
520 .long 1b,2b
521 .popsection
522 PTGS_TO_GS_EX
523 ENDPROC(ia32_sysenter_target)
525 /*
526 * syscall stub including irq exit should be protected against kprobes
527 */
528 .pushsection .kprobes.text, "ax"
529 # system call handler stub
530 ENTRY(system_call)
531 RING0_INT_FRAME # can't unwind into user space anyway
532 pushl %eax # save orig_eax
533 CFI_ADJUST_CFA_OFFSET 4
534 SAVE_ALL
535 GET_THREAD_INFO(%ebp)
536 # system call tracing in operation / emulation
537 testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%ebp)
538 jnz syscall_trace_entry
539 cmpl $(nr_syscalls), %eax
540 jae syscall_badsys
541 syscall_call:
542 call *sys_call_table(,%eax,4)
543 movl %eax,PT_EAX(%esp) # store the return value
544 syscall_exit:
545 LOCKDEP_SYS_EXIT
546 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
547 # setting need_resched or sigpending
548 # between sampling and the iret
549 TRACE_IRQS_OFF
550 movl TI_flags(%ebp), %ecx
551 testl $_TIF_ALLWORK_MASK, %ecx # current->work
552 jne syscall_exit_work
554 restore_all:
555 TRACE_IRQS_IRET
556 restore_all_notrace:
557 movl PT_EFLAGS(%esp), %eax # mix EFLAGS, SS and CS
558 # Warning: PT_OLDSS(%esp) contains the wrong/random values if we
559 # are returning to the kernel.
560 # See comments in process.c:copy_thread() for details.
561 movb PT_OLDSS(%esp), %ah
562 movb PT_CS(%esp), %al
563 andl $(X86_EFLAGS_VM | (SEGMENT_TI_MASK << 8) | SEGMENT_RPL_MASK), %eax
564 cmpl $((SEGMENT_LDT << 8) | USER_RPL), %eax
565 CFI_REMEMBER_STATE
566 je ldt_ss # returning to user-space with LDT SS
567 restore_nocheck:
568 RESTORE_REGS 4 # skip orig_eax/error_code
569 CFI_ADJUST_CFA_OFFSET -4
570 irq_return:
571 INTERRUPT_RETURN
572 .section .fixup,"ax"
573 ENTRY(iret_exc)
574 pushl $0 # no error code
575 pushl $do_iret_error
576 jmp error_code
577 .previous
578 .section __ex_table,"a"
579 .align 4
580 .long irq_return,iret_exc
581 .previous
583 CFI_RESTORE_STATE
584 ldt_ss:
585 larl PT_OLDSS(%esp), %eax
586 jnz restore_nocheck
587 testl $0x00400000, %eax # returning to 32bit stack?
588 jnz restore_nocheck # allright, normal return
590 #ifdef CONFIG_PARAVIRT
591 /*
592 * The kernel can't run on a non-flat stack if paravirt mode
593 * is active. Rather than try to fixup the high bits of
594 * ESP, bypass this code entirely. This may break DOSemu
595 * and/or Wine support in a paravirt VM, although the option
596 * is still available to implement the setting of the high
597 * 16-bits in the INTERRUPT_RETURN paravirt-op.
598 */
599 cmpl $0, pv_info+PARAVIRT_enabled
600 jne restore_nocheck
601 #endif
603 /*
604 * Setup and switch to ESPFIX stack
605 *
606 * We're returning to userspace with a 16 bit stack. The CPU will not
607 * restore the high word of ESP for us on executing iret... This is an
608 * "official" bug of all the x86-compatible CPUs, which we can work
609 * around to make dosemu and wine happy. We do this by preloading the
610 * high word of ESP with the high word of the userspace ESP while
611 * compensating for the offset by changing to the ESPFIX segment with
612 * a base address that matches for the difference.
613 */
614 mov %esp, %edx /* load kernel esp */
615 mov PT_OLDESP(%esp), %eax /* load userspace esp */
616 mov %dx, %ax /* eax: new kernel esp */
617 sub %eax, %edx /* offset (low word is 0) */
618 PER_CPU(gdt_page, %ebx)
619 shr $16, %edx
620 mov %dl, GDT_ENTRY_ESPFIX_SS * 8 + 4(%ebx) /* bits 16..23 */
621 mov %dh, GDT_ENTRY_ESPFIX_SS * 8 + 7(%ebx) /* bits 24..31 */
622 pushl $__ESPFIX_SS
623 CFI_ADJUST_CFA_OFFSET 4
624 push %eax /* new kernel esp */
625 CFI_ADJUST_CFA_OFFSET 4
626 /* Disable interrupts, but do not irqtrace this section: we
627 * will soon execute iret and the tracer was already set to
628 * the irqstate after the iret */
629 DISABLE_INTERRUPTS(CLBR_EAX)
630 lss (%esp), %esp /* switch to espfix segment */
631 CFI_ADJUST_CFA_OFFSET -8
632 jmp restore_nocheck
633 CFI_ENDPROC
634 ENDPROC(system_call)
636 # perform work that needs to be done immediately before resumption
637 ALIGN
638 RING0_PTREGS_FRAME # can't unwind into user space anyway
639 work_pending:
640 testb $_TIF_NEED_RESCHED, %cl
641 jz work_notifysig
642 work_resched:
643 call schedule
644 LOCKDEP_SYS_EXIT
645 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
646 # setting need_resched or sigpending
647 # between sampling and the iret
648 TRACE_IRQS_OFF
649 movl TI_flags(%ebp), %ecx
650 andl $_TIF_WORK_MASK, %ecx # is there any work to be done other
651 # than syscall tracing?
652 jz restore_all
653 testb $_TIF_NEED_RESCHED, %cl
654 jnz work_resched
656 work_notifysig: # deal with pending signals and
657 # notify-resume requests
658 #ifdef CONFIG_VM86
659 testl $X86_EFLAGS_VM, PT_EFLAGS(%esp)
660 movl %esp, %eax
661 jne work_notifysig_v86 # returning to kernel-space or
662 # vm86-space
663 xorl %edx, %edx
664 call do_notify_resume
665 jmp resume_userspace_sig
667 ALIGN
668 work_notifysig_v86:
669 pushl %ecx # save ti_flags for do_notify_resume
670 CFI_ADJUST_CFA_OFFSET 4
671 call save_v86_state # %eax contains pt_regs pointer
672 popl %ecx
673 CFI_ADJUST_CFA_OFFSET -4
674 movl %eax, %esp
675 #else
676 movl %esp, %eax
677 #endif
678 xorl %edx, %edx
679 call do_notify_resume
680 jmp resume_userspace_sig
681 END(work_pending)
683 # perform syscall exit tracing
684 ALIGN
685 syscall_trace_entry:
686 movl $-ENOSYS,PT_EAX(%esp)
687 movl %esp, %eax
688 call syscall_trace_enter
689 /* What it returned is what we'll actually use. */
690 cmpl $(nr_syscalls), %eax
691 jnae syscall_call
692 jmp syscall_exit
693 END(syscall_trace_entry)
695 # perform syscall exit tracing
696 ALIGN
697 syscall_exit_work:
698 testl $_TIF_WORK_SYSCALL_EXIT, %ecx
699 jz work_pending
700 TRACE_IRQS_ON
701 ENABLE_INTERRUPTS(CLBR_ANY) # could let syscall_trace_leave() call
702 # schedule() instead
703 movl %esp, %eax
704 call syscall_trace_leave
705 jmp resume_userspace
706 END(syscall_exit_work)
707 CFI_ENDPROC
709 RING0_INT_FRAME # can't unwind into user space anyway
710 syscall_fault:
711 GET_THREAD_INFO(%ebp)
712 movl $-EFAULT,PT_EAX(%esp)
713 jmp resume_userspace
714 END(syscall_fault)
716 syscall_badsys:
717 movl $-ENOSYS,PT_EAX(%esp)
718 jmp resume_userspace
719 END(syscall_badsys)
720 CFI_ENDPROC
721 /*
722 * End of kprobes section
723 */
724 .popsection
726 /*
727 * System calls that need a pt_regs pointer.
728 */
729 #define PTREGSCALL0(name) \
730 ALIGN; \
731 ptregs_##name: \
732 leal 4(%esp),%eax; \
733 jmp sys_##name;
735 #define PTREGSCALL1(name) \
736 ALIGN; \
737 ptregs_##name: \
738 leal 4(%esp),%edx; \
739 movl (PT_EBX+4)(%esp),%eax; \
740 jmp sys_##name;
742 #define PTREGSCALL2(name) \
743 ALIGN; \
744 ptregs_##name: \
745 leal 4(%esp),%ecx; \
746 movl (PT_ECX+4)(%esp),%edx; \
747 movl (PT_EBX+4)(%esp),%eax; \
748 jmp sys_##name;
750 #define PTREGSCALL3(name) \
751 ALIGN; \
752 ptregs_##name: \
753 leal 4(%esp),%eax; \
754 pushl %eax; \
755 movl PT_EDX(%eax),%ecx; \
756 movl PT_ECX(%eax),%edx; \
757 movl PT_EBX(%eax),%eax; \
758 call sys_##name; \
759 addl $4,%esp; \
760 ret
762 PTREGSCALL1(iopl)
763 PTREGSCALL0(fork)
764 PTREGSCALL0(vfork)
765 PTREGSCALL3(execve)
766 PTREGSCALL2(sigaltstack)
767 PTREGSCALL0(sigreturn)
768 PTREGSCALL0(rt_sigreturn)
769 PTREGSCALL2(vm86)
770 PTREGSCALL1(vm86old)
772 /* Clone is an oddball. The 4th arg is in %edi */
773 ALIGN;
774 ptregs_clone:
775 leal 4(%esp),%eax
776 pushl %eax
777 pushl PT_EDI(%eax)
778 movl PT_EDX(%eax),%ecx
779 movl PT_ECX(%eax),%edx
780 movl PT_EBX(%eax),%eax
781 call sys_clone
782 addl $8,%esp
783 ret
785 .macro FIXUP_ESPFIX_STACK
786 /*
787 * Switch back for ESPFIX stack to the normal zerobased stack
788 *
789 * We can't call C functions using the ESPFIX stack. This code reads
790 * the high word of the segment base from the GDT and swiches to the
791 * normal stack and adjusts ESP with the matching offset.
792 */
793 /* fixup the stack */
794 PER_CPU(gdt_page, %ebx)
795 mov GDT_ENTRY_ESPFIX_SS * 8 + 4(%ebx), %al /* bits 16..23 */
796 mov GDT_ENTRY_ESPFIX_SS * 8 + 7(%ebx), %ah /* bits 24..31 */
797 shl $16, %eax
798 addl %esp, %eax /* the adjusted stack pointer */
799 pushl $__KERNEL_DS
800 CFI_ADJUST_CFA_OFFSET 4
801 pushl %eax
802 CFI_ADJUST_CFA_OFFSET 4
803 lss (%esp), %esp /* switch to the normal stack segment */
804 CFI_ADJUST_CFA_OFFSET -8
805 .endm
806 .macro UNWIND_ESPFIX_STACK
807 movl %ss, %eax
808 /* see if on espfix stack */
809 cmpw $__ESPFIX_SS, %ax
810 jne 27f
811 movl $__KERNEL_DS, %eax
812 movl %eax, %ds
813 movl %eax, %es
814 /* switch to normal stack */
815 FIXUP_ESPFIX_STACK
816 27:
817 .endm
819 /*
820 * Build the entry stubs and pointer table with some assembler magic.
821 * We pack 7 stubs into a single 32-byte chunk, which will fit in a
822 * single cache line on all modern x86 implementations.
823 */
824 .section .init.rodata,"a"
825 ENTRY(interrupt)
826 .text
827 .p2align 5
828 .p2align CONFIG_X86_L1_CACHE_SHIFT
829 ENTRY(irq_entries_start)
830 RING0_INT_FRAME
831 vector=FIRST_EXTERNAL_VECTOR
832 .rept (NR_VECTORS-FIRST_EXTERNAL_VECTOR+6)/7
833 .balign 32
834 .rept 7
835 .if vector < NR_VECTORS
836 .if vector <> FIRST_EXTERNAL_VECTOR
837 CFI_ADJUST_CFA_OFFSET -4
838 .endif
839 1: pushl $(~vector+0x80) /* Note: always in signed byte range */
840 CFI_ADJUST_CFA_OFFSET 4
841 .if ((vector-FIRST_EXTERNAL_VECTOR)%7) <> 6
842 jmp 2f
843 .endif
844 .previous
845 .long 1b
846 .text
847 vector=vector+1
848 .endif
849 .endr
850 2: jmp common_interrupt
851 .endr
852 END(irq_entries_start)
854 .previous
855 END(interrupt)
856 .previous
858 /*
859 * the CPU automatically disables interrupts when executing an IRQ vector,
860 * so IRQ-flags tracing has to follow that:
861 */
862 .p2align CONFIG_X86_L1_CACHE_SHIFT
863 common_interrupt:
864 addl $-0x80,(%esp) /* Adjust vector into the [-256,-1] range */
865 SAVE_ALL
866 TRACE_IRQS_OFF
867 movl %esp,%eax
868 call do_IRQ
869 jmp ret_from_intr
870 ENDPROC(common_interrupt)
871 CFI_ENDPROC
873 /*
874 * Irq entries should be protected against kprobes
875 */
876 .pushsection .kprobes.text, "ax"
877 #define BUILD_INTERRUPT3(name, nr, fn) \
878 ENTRY(name) \
879 RING0_INT_FRAME; \
880 pushl $~(nr); \
881 CFI_ADJUST_CFA_OFFSET 4; \
882 SAVE_ALL; \
883 TRACE_IRQS_OFF \
884 movl %esp,%eax; \
885 call fn; \
886 jmp ret_from_intr; \
887 CFI_ENDPROC; \
888 ENDPROC(name)
890 #define BUILD_INTERRUPT(name, nr) BUILD_INTERRUPT3(name, nr, smp_##name)
892 /* The include is where all of the SMP etc. interrupts come from */
893 #include <asm/entry_arch.h>
895 ENTRY(coprocessor_error)
896 RING0_INT_FRAME
897 pushl $0
898 CFI_ADJUST_CFA_OFFSET 4
899 pushl $do_coprocessor_error
900 CFI_ADJUST_CFA_OFFSET 4
901 jmp error_code
902 CFI_ENDPROC
903 END(coprocessor_error)
905 ENTRY(simd_coprocessor_error)
906 RING0_INT_FRAME
907 pushl $0
908 CFI_ADJUST_CFA_OFFSET 4
909 #ifdef CONFIG_X86_INVD_BUG
910 /* AMD 486 bug: invd from userspace calls exception 19 instead of #GP */
911 661: pushl $do_general_protection
912 662:
913 .section .altinstructions,"a"
914 .balign 4
915 .long 661b
916 .long 663f
917 .byte X86_FEATURE_XMM
918 .byte 662b-661b
919 .byte 664f-663f
920 .previous
921 .section .altinstr_replacement,"ax"
922 663: pushl $do_simd_coprocessor_error
923 664:
924 .previous
925 #else
926 pushl $do_simd_coprocessor_error
927 #endif
928 CFI_ADJUST_CFA_OFFSET 4
929 jmp error_code
930 CFI_ENDPROC
931 END(simd_coprocessor_error)
933 ENTRY(device_not_available)
934 RING0_INT_FRAME
935 pushl $-1 # mark this as an int
936 CFI_ADJUST_CFA_OFFSET 4
937 pushl $do_device_not_available
938 CFI_ADJUST_CFA_OFFSET 4
939 jmp error_code
940 CFI_ENDPROC
941 END(device_not_available)
943 #ifdef CONFIG_PARAVIRT
944 ENTRY(native_iret)
945 iret
946 .section __ex_table,"a"
947 .align 4
948 .long native_iret, iret_exc
949 .previous
950 END(native_iret)
952 ENTRY(native_irq_enable_sysexit)
953 sti
954 sysexit
955 END(native_irq_enable_sysexit)
956 #endif
958 ENTRY(overflow)
959 RING0_INT_FRAME
960 pushl $0
961 CFI_ADJUST_CFA_OFFSET 4
962 pushl $do_overflow
963 CFI_ADJUST_CFA_OFFSET 4
964 jmp error_code
965 CFI_ENDPROC
966 END(overflow)
968 ENTRY(bounds)
969 RING0_INT_FRAME
970 pushl $0
971 CFI_ADJUST_CFA_OFFSET 4
972 pushl $do_bounds
973 CFI_ADJUST_CFA_OFFSET 4
974 jmp error_code
975 CFI_ENDPROC
976 END(bounds)
978 ENTRY(invalid_op)
979 RING0_INT_FRAME
980 pushl $0
981 CFI_ADJUST_CFA_OFFSET 4
982 pushl $do_invalid_op
983 CFI_ADJUST_CFA_OFFSET 4
984 jmp error_code
985 CFI_ENDPROC
986 END(invalid_op)
988 ENTRY(coprocessor_segment_overrun)
989 RING0_INT_FRAME
990 pushl $0
991 CFI_ADJUST_CFA_OFFSET 4
992 pushl $do_coprocessor_segment_overrun
993 CFI_ADJUST_CFA_OFFSET 4
994 jmp error_code
995 CFI_ENDPROC
996 END(coprocessor_segment_overrun)
998 ENTRY(invalid_TSS)
999 RING0_EC_FRAME
1000 pushl $do_invalid_TSS
1001 CFI_ADJUST_CFA_OFFSET 4
1002 jmp error_code
1003 CFI_ENDPROC
1004 END(invalid_TSS)
1006 ENTRY(segment_not_present)
1007 RING0_EC_FRAME
1008 pushl $do_segment_not_present
1009 CFI_ADJUST_CFA_OFFSET 4
1010 jmp error_code
1011 CFI_ENDPROC
1012 END(segment_not_present)
1014 ENTRY(stack_segment)
1015 RING0_EC_FRAME
1016 pushl $do_stack_segment
1017 CFI_ADJUST_CFA_OFFSET 4
1018 jmp error_code
1019 CFI_ENDPROC
1020 END(stack_segment)
1022 ENTRY(alignment_check)
1023 RING0_EC_FRAME
1024 pushl $do_alignment_check
1025 CFI_ADJUST_CFA_OFFSET 4
1026 jmp error_code
1027 CFI_ENDPROC
1028 END(alignment_check)
1030 ENTRY(divide_error)
1031 RING0_INT_FRAME
1032 pushl $0 # no error code
1033 CFI_ADJUST_CFA_OFFSET 4
1034 pushl $do_divide_error
1035 CFI_ADJUST_CFA_OFFSET 4
1036 jmp error_code
1037 CFI_ENDPROC
1038 END(divide_error)
1040 #ifdef CONFIG_X86_MCE
1041 ENTRY(machine_check)
1042 RING0_INT_FRAME
1043 pushl $0
1044 CFI_ADJUST_CFA_OFFSET 4
1045 pushl machine_check_vector
1046 CFI_ADJUST_CFA_OFFSET 4
1047 jmp error_code
1048 CFI_ENDPROC
1049 END(machine_check)
1050 #endif
1052 ENTRY(spurious_interrupt_bug)
1053 RING0_INT_FRAME
1054 pushl $0
1055 CFI_ADJUST_CFA_OFFSET 4
1056 pushl $do_spurious_interrupt_bug
1057 CFI_ADJUST_CFA_OFFSET 4
1058 jmp error_code
1059 CFI_ENDPROC
1060 END(spurious_interrupt_bug)
1061 /*
1062 * End of kprobes section
1063 */
1064 .popsection
1066 ENTRY(kernel_thread_helper)
1067 pushl $0 # fake return address for unwinder
1068 CFI_STARTPROC
1069 movl %edi,%eax
1070 call *%esi
1071 call do_exit
1072 ud2 # padding for call trace
1073 CFI_ENDPROC
1074 ENDPROC(kernel_thread_helper)
1076 #ifdef CONFIG_XEN
1077 /* Xen doesn't set %esp to be precisely what the normal sysenter
1078 entrypoint expects, so fix it up before using the normal path. */
1079 ENTRY(xen_sysenter_target)
1080 RING0_INT_FRAME
1081 addl $5*4, %esp /* remove xen-provided frame */
1082 CFI_ADJUST_CFA_OFFSET -5*4
1083 jmp sysenter_past_esp
1084 CFI_ENDPROC
1086 ENTRY(xen_hypervisor_callback)
1087 CFI_STARTPROC
1088 pushl $0
1089 CFI_ADJUST_CFA_OFFSET 4
1090 SAVE_ALL
1091 TRACE_IRQS_OFF
1093 /* Check to see if we got the event in the critical
1094 region in xen_iret_direct, after we've reenabled
1095 events and checked for pending events. This simulates
1096 iret instruction's behaviour where it delivers a
1097 pending interrupt when enabling interrupts. */
1098 movl PT_EIP(%esp),%eax
1099 cmpl $xen_iret_start_crit,%eax
1100 jb 1f
1101 cmpl $xen_iret_end_crit,%eax
1102 jae 1f
1104 jmp xen_iret_crit_fixup
1106 ENTRY(xen_do_upcall)
1107 1: mov %esp, %eax
1108 call xen_evtchn_do_upcall
1109 jmp ret_from_intr
1110 CFI_ENDPROC
1111 ENDPROC(xen_hypervisor_callback)
1113 # Hypervisor uses this for application faults while it executes.
1114 # We get here for two reasons:
1115 # 1. Fault while reloading DS, ES, FS or GS
1116 # 2. Fault while executing IRET
1117 # Category 1 we fix up by reattempting the load, and zeroing the segment
1118 # register if the load fails.
1119 # Category 2 we fix up by jumping to do_iret_error. We cannot use the
1120 # normal Linux return path in this case because if we use the IRET hypercall
1121 # to pop the stack frame we end up in an infinite loop of failsafe callbacks.
1122 # We distinguish between categories by maintaining a status value in EAX.
1123 ENTRY(xen_failsafe_callback)
1124 CFI_STARTPROC
1125 pushl %eax
1126 CFI_ADJUST_CFA_OFFSET 4
1127 movl $1,%eax
1128 1: mov 4(%esp),%ds
1129 2: mov 8(%esp),%es
1130 3: mov 12(%esp),%fs
1131 4: mov 16(%esp),%gs
1132 testl %eax,%eax
1133 popl %eax
1134 CFI_ADJUST_CFA_OFFSET -4
1135 lea 16(%esp),%esp
1136 CFI_ADJUST_CFA_OFFSET -16
1137 jz 5f
1138 addl $16,%esp
1139 jmp iret_exc # EAX != 0 => Category 2 (Bad IRET)
1140 5: pushl $0 # EAX == 0 => Category 1 (Bad segment)
1141 CFI_ADJUST_CFA_OFFSET 4
1142 SAVE_ALL
1143 jmp ret_from_exception
1144 CFI_ENDPROC
1146 .section .fixup,"ax"
1147 6: xorl %eax,%eax
1148 movl %eax,4(%esp)
1149 jmp 1b
1150 7: xorl %eax,%eax
1151 movl %eax,8(%esp)
1152 jmp 2b
1153 8: xorl %eax,%eax
1154 movl %eax,12(%esp)
1155 jmp 3b
1156 9: xorl %eax,%eax
1157 movl %eax,16(%esp)
1158 jmp 4b
1159 .previous
1160 .section __ex_table,"a"
1161 .align 4
1162 .long 1b,6b
1163 .long 2b,7b
1164 .long 3b,8b
1165 .long 4b,9b
1166 .previous
1167 ENDPROC(xen_failsafe_callback)
1169 #endif /* CONFIG_XEN */
1171 #ifdef CONFIG_FUNCTION_TRACER
1172 #ifdef CONFIG_DYNAMIC_FTRACE
1174 ENTRY(mcount)
1175 ret
1176 END(mcount)
1178 ENTRY(ftrace_caller)
1179 cmpl $0, function_trace_stop
1180 jne ftrace_stub
1182 pushl %eax
1183 pushl %ecx
1184 pushl %edx
1185 movl 0xc(%esp), %eax
1186 movl 0x4(%ebp), %edx
1187 subl $MCOUNT_INSN_SIZE, %eax
1189 .globl ftrace_call
1190 ftrace_call:
1191 call ftrace_stub
1193 popl %edx
1194 popl %ecx
1195 popl %eax
1196 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1197 .globl ftrace_graph_call
1198 ftrace_graph_call:
1199 jmp ftrace_stub
1200 #endif
1202 .globl ftrace_stub
1203 ftrace_stub:
1204 ret
1205 END(ftrace_caller)
1207 #else /* ! CONFIG_DYNAMIC_FTRACE */
1209 ENTRY(mcount)
1210 cmpl $0, function_trace_stop
1211 jne ftrace_stub
1213 cmpl $ftrace_stub, ftrace_trace_function
1214 jnz trace
1215 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1216 cmpl $ftrace_stub, ftrace_graph_return
1217 jnz ftrace_graph_caller
1219 cmpl $ftrace_graph_entry_stub, ftrace_graph_entry
1220 jnz ftrace_graph_caller
1221 #endif
1222 .globl ftrace_stub
1223 ftrace_stub:
1224 ret
1226 /* taken from glibc */
1227 trace:
1228 pushl %eax
1229 pushl %ecx
1230 pushl %edx
1231 movl 0xc(%esp), %eax
1232 movl 0x4(%ebp), %edx
1233 subl $MCOUNT_INSN_SIZE, %eax
1235 call *ftrace_trace_function
1237 popl %edx
1238 popl %ecx
1239 popl %eax
1240 jmp ftrace_stub
1241 END(mcount)
1242 #endif /* CONFIG_DYNAMIC_FTRACE */
1243 #endif /* CONFIG_FUNCTION_TRACER */
1245 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1246 ENTRY(ftrace_graph_caller)
1247 cmpl $0, function_trace_stop
1248 jne ftrace_stub
1250 pushl %eax
1251 pushl %ecx
1252 pushl %edx
1253 movl 0xc(%esp), %edx
1254 lea 0x4(%ebp), %eax
1255 movl (%ebp), %ecx
1256 subl $MCOUNT_INSN_SIZE, %edx
1257 call prepare_ftrace_return
1258 popl %edx
1259 popl %ecx
1260 popl %eax
1261 ret
1262 END(ftrace_graph_caller)
1264 .globl return_to_handler
1265 return_to_handler:
1266 pushl %eax
1267 pushl %edx
1268 movl %ebp, %eax
1269 call ftrace_return_to_handler
1270 movl %eax, %ecx
1271 popl %edx
1272 popl %eax
1273 jmp *%ecx
1274 #endif
1276 .section .rodata,"a"
1277 #include "syscall_table_32.S"
1279 syscall_table_size=(.-sys_call_table)
1281 /*
1282 * Some functions should be protected against kprobes
1283 */
1284 .pushsection .kprobes.text, "ax"
1286 ENTRY(page_fault)
1287 RING0_EC_FRAME
1288 pushl $do_page_fault
1289 CFI_ADJUST_CFA_OFFSET 4
1290 ALIGN
1291 error_code:
1292 /* the function address is in %gs's slot on the stack */
1293 pushl %fs
1294 CFI_ADJUST_CFA_OFFSET 4
1295 /*CFI_REL_OFFSET fs, 0*/
1296 pushl %es
1297 CFI_ADJUST_CFA_OFFSET 4
1298 /*CFI_REL_OFFSET es, 0*/
1299 pushl %ds
1300 CFI_ADJUST_CFA_OFFSET 4
1301 /*CFI_REL_OFFSET ds, 0*/
1302 pushl %eax
1303 CFI_ADJUST_CFA_OFFSET 4
1304 CFI_REL_OFFSET eax, 0
1305 pushl %ebp
1306 CFI_ADJUST_CFA_OFFSET 4
1307 CFI_REL_OFFSET ebp, 0
1308 pushl %edi
1309 CFI_ADJUST_CFA_OFFSET 4
1310 CFI_REL_OFFSET edi, 0
1311 pushl %esi
1312 CFI_ADJUST_CFA_OFFSET 4
1313 CFI_REL_OFFSET esi, 0
1314 pushl %edx
1315 CFI_ADJUST_CFA_OFFSET 4
1316 CFI_REL_OFFSET edx, 0
1317 pushl %ecx
1318 CFI_ADJUST_CFA_OFFSET 4
1319 CFI_REL_OFFSET ecx, 0
1320 pushl %ebx
1321 CFI_ADJUST_CFA_OFFSET 4
1322 CFI_REL_OFFSET ebx, 0
1323 cld
1324 movl $(__KERNEL_PERCPU), %ecx
1325 movl %ecx, %fs
1326 UNWIND_ESPFIX_STACK
1327 GS_TO_REG %ecx
1328 movl PT_GS(%esp), %edi # get the function address
1329 movl PT_ORIG_EAX(%esp), %edx # get the error code
1330 movl $-1, PT_ORIG_EAX(%esp) # no syscall to restart
1331 REG_TO_PTGS %ecx
1332 SET_KERNEL_GS %ecx
1333 movl $(__USER_DS), %ecx
1334 movl %ecx, %ds
1335 movl %ecx, %es
1336 TRACE_IRQS_OFF
1337 movl %esp,%eax # pt_regs pointer
1338 call *%edi
1339 jmp ret_from_exception
1340 CFI_ENDPROC
1341 END(page_fault)
1343 /*
1344 * Debug traps and NMI can happen at the one SYSENTER instruction
1345 * that sets up the real kernel stack. Check here, since we can't
1346 * allow the wrong stack to be used.
1347 *
1348 * "TSS_sysenter_sp0+12" is because the NMI/debug handler will have
1349 * already pushed 3 words if it hits on the sysenter instruction:
1350 * eflags, cs and eip.
1351 *
1352 * We just load the right stack, and push the three (known) values
1353 * by hand onto the new stack - while updating the return eip past
1354 * the instruction that would have done it for sysenter.
1355 */
1356 .macro FIX_STACK offset ok label
1357 cmpw $__KERNEL_CS, 4(%esp)
1358 jne \ok
1359 \label:
1360 movl TSS_sysenter_sp0 + \offset(%esp), %esp
1361 CFI_DEF_CFA esp, 0
1362 CFI_UNDEFINED eip
1363 pushfl
1364 CFI_ADJUST_CFA_OFFSET 4
1365 pushl $__KERNEL_CS
1366 CFI_ADJUST_CFA_OFFSET 4
1367 pushl $sysenter_past_esp
1368 CFI_ADJUST_CFA_OFFSET 4
1369 CFI_REL_OFFSET eip, 0
1370 .endm
1372 ENTRY(debug)
1373 RING0_INT_FRAME
1374 cmpl $ia32_sysenter_target,(%esp)
1375 jne debug_stack_correct
1376 FIX_STACK 12, debug_stack_correct, debug_esp_fix_insn
1377 debug_stack_correct:
1378 pushl $-1 # mark this as an int
1379 CFI_ADJUST_CFA_OFFSET 4
1380 SAVE_ALL
1381 TRACE_IRQS_OFF
1382 xorl %edx,%edx # error code 0
1383 movl %esp,%eax # pt_regs pointer
1384 call do_debug
1385 jmp ret_from_exception
1386 CFI_ENDPROC
1387 END(debug)
1389 /*
1390 * NMI is doubly nasty. It can happen _while_ we're handling
1391 * a debug fault, and the debug fault hasn't yet been able to
1392 * clear up the stack. So we first check whether we got an
1393 * NMI on the sysenter entry path, but after that we need to
1394 * check whether we got an NMI on the debug path where the debug
1395 * fault happened on the sysenter path.
1396 */
1397 ENTRY(nmi)
1398 RING0_INT_FRAME
1399 pushl %eax
1400 CFI_ADJUST_CFA_OFFSET 4
1401 movl %ss, %eax
1402 cmpw $__ESPFIX_SS, %ax
1403 popl %eax
1404 CFI_ADJUST_CFA_OFFSET -4
1405 je nmi_espfix_stack
1406 cmpl $ia32_sysenter_target,(%esp)
1407 je nmi_stack_fixup
1408 pushl %eax
1409 CFI_ADJUST_CFA_OFFSET 4
1410 movl %esp,%eax
1411 /* Do not access memory above the end of our stack page,
1412 * it might not exist.
1413 */
1414 andl $(THREAD_SIZE-1),%eax
1415 cmpl $(THREAD_SIZE-20),%eax
1416 popl %eax
1417 CFI_ADJUST_CFA_OFFSET -4
1418 jae nmi_stack_correct
1419 cmpl $ia32_sysenter_target,12(%esp)
1420 je nmi_debug_stack_check
1421 nmi_stack_correct:
1422 /* We have a RING0_INT_FRAME here */
1423 pushl %eax
1424 CFI_ADJUST_CFA_OFFSET 4
1425 SAVE_ALL
1426 xorl %edx,%edx # zero error code
1427 movl %esp,%eax # pt_regs pointer
1428 call do_nmi
1429 jmp restore_all_notrace
1430 CFI_ENDPROC
1432 nmi_stack_fixup:
1433 RING0_INT_FRAME
1434 FIX_STACK 12, nmi_stack_correct, 1
1435 jmp nmi_stack_correct
1437 nmi_debug_stack_check:
1438 /* We have a RING0_INT_FRAME here */
1439 cmpw $__KERNEL_CS,16(%esp)
1440 jne nmi_stack_correct
1441 cmpl $debug,(%esp)
1442 jb nmi_stack_correct
1443 cmpl $debug_esp_fix_insn,(%esp)
1444 ja nmi_stack_correct
1445 FIX_STACK 24, nmi_stack_correct, 1
1446 jmp nmi_stack_correct
1448 nmi_espfix_stack:
1449 /* We have a RING0_INT_FRAME here.
1450 *
1451 * create the pointer to lss back
1452 */
1453 pushl %ss
1454 CFI_ADJUST_CFA_OFFSET 4
1455 pushl %esp
1456 CFI_ADJUST_CFA_OFFSET 4
1457 addl $4, (%esp)
1458 /* copy the iret frame of 12 bytes */
1459 .rept 3
1460 pushl 16(%esp)
1461 CFI_ADJUST_CFA_OFFSET 4
1462 .endr
1463 pushl %eax
1464 CFI_ADJUST_CFA_OFFSET 4
1465 SAVE_ALL
1466 FIXUP_ESPFIX_STACK # %eax == %esp
1467 xorl %edx,%edx # zero error code
1468 call do_nmi
1469 RESTORE_REGS
1470 lss 12+4(%esp), %esp # back to espfix stack
1471 CFI_ADJUST_CFA_OFFSET -24
1472 jmp irq_return
1473 CFI_ENDPROC
1474 END(nmi)
1476 ENTRY(int3)
1477 RING0_INT_FRAME
1478 pushl $-1 # mark this as an int
1479 CFI_ADJUST_CFA_OFFSET 4
1480 SAVE_ALL
1481 TRACE_IRQS_OFF
1482 xorl %edx,%edx # zero error code
1483 movl %esp,%eax # pt_regs pointer
1484 call do_int3
1485 jmp ret_from_exception
1486 CFI_ENDPROC
1487 END(int3)
1489 ENTRY(general_protection)
1490 RING0_EC_FRAME
1491 pushl $do_general_protection
1492 CFI_ADJUST_CFA_OFFSET 4
1493 jmp error_code
1494 CFI_ENDPROC
1495 END(general_protection)
1497 /*
1498 * End of kprobes section
1499 */
1500 .popsection