| blob | 44a8e0dc6737d9f28ba0fe258655e0d43b02226d |
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 * Interrupt exit functions should be protected against kprobes
338 */
339 .pushsection .kprobes.text, "ax"
340 /*
341 * Return to user mode is not as complex as all this looks,
342 * but we want the default path for a system call return to
343 * go as quickly as possible which is why some of this is
344 * less clear than it otherwise should be.
345 */
347 # userspace resumption stub bypassing syscall exit tracing
348 ALIGN
349 RING0_PTREGS_FRAME
350 ret_from_exception:
351 preempt_stop(CLBR_ANY)
352 ret_from_intr:
353 GET_THREAD_INFO(%ebp)
354 check_userspace:
355 movl PT_EFLAGS(%esp), %eax # mix EFLAGS and CS
356 movb PT_CS(%esp), %al
357 andl $(X86_EFLAGS_VM | SEGMENT_RPL_MASK), %eax
358 cmpl $USER_RPL, %eax
359 jb resume_kernel # not returning to v8086 or userspace
361 ENTRY(resume_userspace)
362 LOCKDEP_SYS_EXIT
363 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
364 # setting need_resched or sigpending
365 # between sampling and the iret
366 TRACE_IRQS_OFF
367 movl TI_flags(%ebp), %ecx
368 andl $_TIF_WORK_MASK, %ecx # is there any work to be done on
369 # int/exception return?
370 jne work_pending
371 jmp restore_all
372 END(ret_from_exception)
374 #ifdef CONFIG_PREEMPT
375 ENTRY(resume_kernel)
376 DISABLE_INTERRUPTS(CLBR_ANY)
377 cmpl $0,TI_preempt_count(%ebp) # non-zero preempt_count ?
378 jnz restore_all
379 need_resched:
380 movl TI_flags(%ebp), %ecx # need_resched set ?
381 testb $_TIF_NEED_RESCHED, %cl
382 jz restore_all
383 testl $X86_EFLAGS_IF,PT_EFLAGS(%esp) # interrupts off (exception path) ?
384 jz restore_all
385 call preempt_schedule_irq
386 jmp need_resched
387 END(resume_kernel)
388 #endif
389 CFI_ENDPROC
390 /*
391 * End of kprobes section
392 */
393 .popsection
395 /* SYSENTER_RETURN points to after the "sysenter" instruction in
396 the vsyscall page. See vsyscall-sysentry.S, which defines the symbol. */
398 # sysenter call handler stub
399 ENTRY(ia32_sysenter_target)
400 CFI_STARTPROC simple
401 CFI_SIGNAL_FRAME
402 CFI_DEF_CFA esp, 0
403 CFI_REGISTER esp, ebp
404 movl TSS_sysenter_sp0(%esp),%esp
405 sysenter_past_esp:
406 /*
407 * Interrupts are disabled here, but we can't trace it until
408 * enough kernel state to call TRACE_IRQS_OFF can be called - but
409 * we immediately enable interrupts at that point anyway.
410 */
411 pushl $(__USER_DS)
412 CFI_ADJUST_CFA_OFFSET 4
413 /*CFI_REL_OFFSET ss, 0*/
414 pushl %ebp
415 CFI_ADJUST_CFA_OFFSET 4
416 CFI_REL_OFFSET esp, 0
417 pushfl
418 orl $X86_EFLAGS_IF, (%esp)
419 CFI_ADJUST_CFA_OFFSET 4
420 pushl $(__USER_CS)
421 CFI_ADJUST_CFA_OFFSET 4
422 /*CFI_REL_OFFSET cs, 0*/
423 /*
424 * Push current_thread_info()->sysenter_return to the stack.
425 * A tiny bit of offset fixup is necessary - 4*4 means the 4 words
426 * pushed above; +8 corresponds to copy_thread's esp0 setting.
427 */
428 pushl (TI_sysenter_return-THREAD_SIZE+8+4*4)(%esp)
429 CFI_ADJUST_CFA_OFFSET 4
430 CFI_REL_OFFSET eip, 0
432 pushl %eax
433 CFI_ADJUST_CFA_OFFSET 4
434 SAVE_ALL
435 ENABLE_INTERRUPTS(CLBR_NONE)
437 /*
438 * Load the potential sixth argument from user stack.
439 * Careful about security.
440 */
441 cmpl $__PAGE_OFFSET-3,%ebp
442 jae syscall_fault
443 1: movl (%ebp),%ebp
444 movl %ebp,PT_EBP(%esp)
445 .section __ex_table,"a"
446 .align 4
447 .long 1b,syscall_fault
448 .previous
450 GET_THREAD_INFO(%ebp)
452 testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%ebp)
453 jnz sysenter_audit
454 sysenter_do_call:
455 cmpl $(nr_syscalls), %eax
456 jae syscall_badsys
457 call *sys_call_table(,%eax,4)
458 movl %eax,PT_EAX(%esp)
459 LOCKDEP_SYS_EXIT
460 DISABLE_INTERRUPTS(CLBR_ANY)
461 TRACE_IRQS_OFF
462 movl TI_flags(%ebp), %ecx
463 testl $_TIF_ALLWORK_MASK, %ecx
464 jne sysexit_audit
465 sysenter_exit:
466 /* if something modifies registers it must also disable sysexit */
467 movl PT_EIP(%esp), %edx
468 movl PT_OLDESP(%esp), %ecx
469 xorl %ebp,%ebp
470 TRACE_IRQS_ON
471 1: mov PT_FS(%esp), %fs
472 PTGS_TO_GS
473 ENABLE_INTERRUPTS_SYSEXIT
475 #ifdef CONFIG_AUDITSYSCALL
476 sysenter_audit:
477 testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
478 jnz syscall_trace_entry
479 addl $4,%esp
480 CFI_ADJUST_CFA_OFFSET -4
481 /* %esi already in 8(%esp) 6th arg: 4th syscall arg */
482 /* %edx already in 4(%esp) 5th arg: 3rd syscall arg */
483 /* %ecx already in 0(%esp) 4th arg: 2nd syscall arg */
484 movl %ebx,%ecx /* 3rd arg: 1st syscall arg */
485 movl %eax,%edx /* 2nd arg: syscall number */
486 movl $AUDIT_ARCH_I386,%eax /* 1st arg: audit arch */
487 call audit_syscall_entry
488 pushl %ebx
489 CFI_ADJUST_CFA_OFFSET 4
490 movl PT_EAX(%esp),%eax /* reload syscall number */
491 jmp sysenter_do_call
493 sysexit_audit:
494 testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %ecx
495 jne syscall_exit_work
496 TRACE_IRQS_ON
497 ENABLE_INTERRUPTS(CLBR_ANY)
498 movl %eax,%edx /* second arg, syscall return value */
499 cmpl $0,%eax /* is it < 0? */
500 setl %al /* 1 if so, 0 if not */
501 movzbl %al,%eax /* zero-extend that */
502 inc %eax /* first arg, 0->1(AUDITSC_SUCCESS), 1->2(AUDITSC_FAILURE) */
503 call audit_syscall_exit
504 DISABLE_INTERRUPTS(CLBR_ANY)
505 TRACE_IRQS_OFF
506 movl TI_flags(%ebp), %ecx
507 testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %ecx
508 jne syscall_exit_work
509 movl PT_EAX(%esp),%eax /* reload syscall return value */
510 jmp sysenter_exit
511 #endif
513 CFI_ENDPROC
514 .pushsection .fixup,"ax"
515 2: movl $0,PT_FS(%esp)
516 jmp 1b
517 .section __ex_table,"a"
518 .align 4
519 .long 1b,2b
520 .popsection
521 PTGS_TO_GS_EX
522 ENDPROC(ia32_sysenter_target)
524 /*
525 * syscall stub including irq exit should be protected against kprobes
526 */
527 .pushsection .kprobes.text, "ax"
528 # system call handler stub
529 ENTRY(system_call)
530 RING0_INT_FRAME # can't unwind into user space anyway
531 pushl %eax # save orig_eax
532 CFI_ADJUST_CFA_OFFSET 4
533 SAVE_ALL
534 GET_THREAD_INFO(%ebp)
535 # system call tracing in operation / emulation
536 testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%ebp)
537 jnz syscall_trace_entry
538 cmpl $(nr_syscalls), %eax
539 jae syscall_badsys
540 syscall_call:
541 call *sys_call_table(,%eax,4)
542 movl %eax,PT_EAX(%esp) # store the return value
543 syscall_exit:
544 LOCKDEP_SYS_EXIT
545 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
546 # setting need_resched or sigpending
547 # between sampling and the iret
548 TRACE_IRQS_OFF
549 movl TI_flags(%ebp), %ecx
550 testl $_TIF_ALLWORK_MASK, %ecx # current->work
551 jne syscall_exit_work
553 restore_all:
554 TRACE_IRQS_IRET
555 restore_all_notrace:
556 movl PT_EFLAGS(%esp), %eax # mix EFLAGS, SS and CS
557 # Warning: PT_OLDSS(%esp) contains the wrong/random values if we
558 # are returning to the kernel.
559 # See comments in process.c:copy_thread() for details.
560 movb PT_OLDSS(%esp), %ah
561 movb PT_CS(%esp), %al
562 andl $(X86_EFLAGS_VM | (SEGMENT_TI_MASK << 8) | SEGMENT_RPL_MASK), %eax
563 cmpl $((SEGMENT_LDT << 8) | USER_RPL), %eax
564 CFI_REMEMBER_STATE
565 je ldt_ss # returning to user-space with LDT SS
566 restore_nocheck:
567 RESTORE_REGS 4 # skip orig_eax/error_code
568 CFI_ADJUST_CFA_OFFSET -4
569 irq_return:
570 INTERRUPT_RETURN
571 .section .fixup,"ax"
572 ENTRY(iret_exc)
573 pushl $0 # no error code
574 pushl $do_iret_error
575 jmp error_code
576 .previous
577 .section __ex_table,"a"
578 .align 4
579 .long irq_return,iret_exc
580 .previous
582 CFI_RESTORE_STATE
583 ldt_ss:
584 larl PT_OLDSS(%esp), %eax
585 jnz restore_nocheck
586 testl $0x00400000, %eax # returning to 32bit stack?
587 jnz restore_nocheck # allright, normal return
589 #ifdef CONFIG_PARAVIRT
590 /*
591 * The kernel can't run on a non-flat stack if paravirt mode
592 * is active. Rather than try to fixup the high bits of
593 * ESP, bypass this code entirely. This may break DOSemu
594 * and/or Wine support in a paravirt VM, although the option
595 * is still available to implement the setting of the high
596 * 16-bits in the INTERRUPT_RETURN paravirt-op.
597 */
598 cmpl $0, pv_info+PARAVIRT_enabled
599 jne restore_nocheck
600 #endif
602 /*
603 * Setup and switch to ESPFIX stack
604 *
605 * We're returning to userspace with a 16 bit stack. The CPU will not
606 * restore the high word of ESP for us on executing iret... This is an
607 * "official" bug of all the x86-compatible CPUs, which we can work
608 * around to make dosemu and wine happy. We do this by preloading the
609 * high word of ESP with the high word of the userspace ESP while
610 * compensating for the offset by changing to the ESPFIX segment with
611 * a base address that matches for the difference.
612 */
613 mov %esp, %edx /* load kernel esp */
614 mov PT_OLDESP(%esp), %eax /* load userspace esp */
615 mov %dx, %ax /* eax: new kernel esp */
616 sub %eax, %edx /* offset (low word is 0) */
617 PER_CPU(gdt_page, %ebx)
618 shr $16, %edx
619 mov %dl, GDT_ENTRY_ESPFIX_SS * 8 + 4(%ebx) /* bits 16..23 */
620 mov %dh, GDT_ENTRY_ESPFIX_SS * 8 + 7(%ebx) /* bits 24..31 */
621 pushl $__ESPFIX_SS
622 CFI_ADJUST_CFA_OFFSET 4
623 push %eax /* new kernel esp */
624 CFI_ADJUST_CFA_OFFSET 4
625 /* Disable interrupts, but do not irqtrace this section: we
626 * will soon execute iret and the tracer was already set to
627 * the irqstate after the iret */
628 DISABLE_INTERRUPTS(CLBR_EAX)
629 lss (%esp), %esp /* switch to espfix segment */
630 CFI_ADJUST_CFA_OFFSET -8
631 jmp restore_nocheck
632 CFI_ENDPROC
633 ENDPROC(system_call)
635 # perform work that needs to be done immediately before resumption
636 ALIGN
637 RING0_PTREGS_FRAME # can't unwind into user space anyway
638 work_pending:
639 testb $_TIF_NEED_RESCHED, %cl
640 jz work_notifysig
641 work_resched:
642 call schedule
643 LOCKDEP_SYS_EXIT
644 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
645 # setting need_resched or sigpending
646 # between sampling and the iret
647 TRACE_IRQS_OFF
648 movl TI_flags(%ebp), %ecx
649 andl $_TIF_WORK_MASK, %ecx # is there any work to be done other
650 # than syscall tracing?
651 jz restore_all
652 testb $_TIF_NEED_RESCHED, %cl
653 jnz work_resched
655 work_notifysig: # deal with pending signals and
656 # notify-resume requests
657 #ifdef CONFIG_VM86
658 testl $X86_EFLAGS_VM, PT_EFLAGS(%esp)
659 movl %esp, %eax
660 jne work_notifysig_v86 # returning to kernel-space or
661 # vm86-space
662 xorl %edx, %edx
663 call do_notify_resume
664 jmp resume_userspace_sig
666 ALIGN
667 work_notifysig_v86:
668 pushl %ecx # save ti_flags for do_notify_resume
669 CFI_ADJUST_CFA_OFFSET 4
670 call save_v86_state # %eax contains pt_regs pointer
671 popl %ecx
672 CFI_ADJUST_CFA_OFFSET -4
673 movl %eax, %esp
674 #else
675 movl %esp, %eax
676 #endif
677 xorl %edx, %edx
678 call do_notify_resume
679 jmp resume_userspace_sig
680 END(work_pending)
682 # perform syscall exit tracing
683 ALIGN
684 syscall_trace_entry:
685 movl $-ENOSYS,PT_EAX(%esp)
686 movl %esp, %eax
687 call syscall_trace_enter
688 /* What it returned is what we'll actually use. */
689 cmpl $(nr_syscalls), %eax
690 jnae syscall_call
691 jmp syscall_exit
692 END(syscall_trace_entry)
694 # perform syscall exit tracing
695 ALIGN
696 syscall_exit_work:
697 testl $_TIF_WORK_SYSCALL_EXIT, %ecx
698 jz work_pending
699 TRACE_IRQS_ON
700 ENABLE_INTERRUPTS(CLBR_ANY) # could let syscall_trace_leave() call
701 # schedule() instead
702 movl %esp, %eax
703 call syscall_trace_leave
704 jmp resume_userspace
705 END(syscall_exit_work)
706 CFI_ENDPROC
708 RING0_INT_FRAME # can't unwind into user space anyway
709 syscall_fault:
710 GET_THREAD_INFO(%ebp)
711 movl $-EFAULT,PT_EAX(%esp)
712 jmp resume_userspace
713 END(syscall_fault)
715 syscall_badsys:
716 movl $-ENOSYS,PT_EAX(%esp)
717 jmp resume_userspace
718 END(syscall_badsys)
719 CFI_ENDPROC
720 /*
721 * End of kprobes section
722 */
723 .popsection
725 /*
726 * System calls that need a pt_regs pointer.
727 */
728 #define PTREGSCALL0(name) \
729 ALIGN; \
730 ptregs_##name: \
731 leal 4(%esp),%eax; \
732 jmp sys_##name;
734 #define PTREGSCALL1(name) \
735 ALIGN; \
736 ptregs_##name: \
737 leal 4(%esp),%edx; \
738 movl (PT_EBX+4)(%esp),%eax; \
739 jmp sys_##name;
741 #define PTREGSCALL2(name) \
742 ALIGN; \
743 ptregs_##name: \
744 leal 4(%esp),%ecx; \
745 movl (PT_ECX+4)(%esp),%edx; \
746 movl (PT_EBX+4)(%esp),%eax; \
747 jmp sys_##name;
749 #define PTREGSCALL3(name) \
750 ALIGN; \
751 ptregs_##name: \
752 leal 4(%esp),%eax; \
753 pushl %eax; \
754 movl PT_EDX(%eax),%ecx; \
755 movl PT_ECX(%eax),%edx; \
756 movl PT_EBX(%eax),%eax; \
757 call sys_##name; \
758 addl $4,%esp; \
759 ret
761 PTREGSCALL1(iopl)
762 PTREGSCALL0(fork)
763 PTREGSCALL0(vfork)
764 PTREGSCALL3(execve)
765 PTREGSCALL2(sigaltstack)
766 PTREGSCALL0(sigreturn)
767 PTREGSCALL0(rt_sigreturn)
768 PTREGSCALL2(vm86)
769 PTREGSCALL1(vm86old)
771 /* Clone is an oddball. The 4th arg is in %edi */
772 ALIGN;
773 ptregs_clone:
774 leal 4(%esp),%eax
775 pushl %eax
776 pushl PT_EDI(%eax)
777 movl PT_EDX(%eax),%ecx
778 movl PT_ECX(%eax),%edx
779 movl PT_EBX(%eax),%eax
780 call sys_clone
781 addl $8,%esp
782 ret
784 .macro FIXUP_ESPFIX_STACK
785 /*
786 * Switch back for ESPFIX stack to the normal zerobased stack
787 *
788 * We can't call C functions using the ESPFIX stack. This code reads
789 * the high word of the segment base from the GDT and swiches to the
790 * normal stack and adjusts ESP with the matching offset.
791 */
792 /* fixup the stack */
793 PER_CPU(gdt_page, %ebx)
794 mov GDT_ENTRY_ESPFIX_SS * 8 + 4(%ebx), %al /* bits 16..23 */
795 mov GDT_ENTRY_ESPFIX_SS * 8 + 7(%ebx), %ah /* bits 24..31 */
796 shl $16, %eax
797 addl %esp, %eax /* the adjusted stack pointer */
798 pushl $__KERNEL_DS
799 CFI_ADJUST_CFA_OFFSET 4
800 pushl %eax
801 CFI_ADJUST_CFA_OFFSET 4
802 lss (%esp), %esp /* switch to the normal stack segment */
803 CFI_ADJUST_CFA_OFFSET -8
804 .endm
805 .macro UNWIND_ESPFIX_STACK
806 movl %ss, %eax
807 /* see if on espfix stack */
808 cmpw $__ESPFIX_SS, %ax
809 jne 27f
810 movl $__KERNEL_DS, %eax
811 movl %eax, %ds
812 movl %eax, %es
813 /* switch to normal stack */
814 FIXUP_ESPFIX_STACK
815 27:
816 .endm
818 /*
819 * Build the entry stubs and pointer table with some assembler magic.
820 * We pack 7 stubs into a single 32-byte chunk, which will fit in a
821 * single cache line on all modern x86 implementations.
822 */
823 .section .init.rodata,"a"
824 ENTRY(interrupt)
825 .text
826 .p2align 5
827 .p2align CONFIG_X86_L1_CACHE_SHIFT
828 ENTRY(irq_entries_start)
829 RING0_INT_FRAME
830 vector=FIRST_EXTERNAL_VECTOR
831 .rept (NR_VECTORS-FIRST_EXTERNAL_VECTOR+6)/7
832 .balign 32
833 .rept 7
834 .if vector < NR_VECTORS
835 .if vector <> FIRST_EXTERNAL_VECTOR
836 CFI_ADJUST_CFA_OFFSET -4
837 .endif
838 1: pushl $(~vector+0x80) /* Note: always in signed byte range */
839 CFI_ADJUST_CFA_OFFSET 4
840 .if ((vector-FIRST_EXTERNAL_VECTOR)%7) <> 6
841 jmp 2f
842 .endif
843 .previous
844 .long 1b
845 .text
846 vector=vector+1
847 .endif
848 .endr
849 2: jmp common_interrupt
850 .endr
851 END(irq_entries_start)
853 .previous
854 END(interrupt)
855 .previous
857 /*
858 * the CPU automatically disables interrupts when executing an IRQ vector,
859 * so IRQ-flags tracing has to follow that:
860 */
861 .p2align CONFIG_X86_L1_CACHE_SHIFT
862 common_interrupt:
863 addl $-0x80,(%esp) /* Adjust vector into the [-256,-1] range */
864 SAVE_ALL
865 TRACE_IRQS_OFF
866 movl %esp,%eax
867 call do_IRQ
868 jmp ret_from_intr
869 ENDPROC(common_interrupt)
870 CFI_ENDPROC
872 /*
873 * Irq entries should be protected against kprobes
874 */
875 .pushsection .kprobes.text, "ax"
876 #define BUILD_INTERRUPT3(name, nr, fn) \
877 ENTRY(name) \
878 RING0_INT_FRAME; \
879 pushl $~(nr); \
880 CFI_ADJUST_CFA_OFFSET 4; \
881 SAVE_ALL; \
882 TRACE_IRQS_OFF \
883 movl %esp,%eax; \
884 call fn; \
885 jmp ret_from_intr; \
886 CFI_ENDPROC; \
887 ENDPROC(name)
889 #define BUILD_INTERRUPT(name, nr) BUILD_INTERRUPT3(name, nr, smp_##name)
891 /* The include is where all of the SMP etc. interrupts come from */
892 #include <asm/entry_arch.h>
894 ENTRY(coprocessor_error)
895 RING0_INT_FRAME
896 pushl $0
897 CFI_ADJUST_CFA_OFFSET 4
898 pushl $do_coprocessor_error
899 CFI_ADJUST_CFA_OFFSET 4
900 jmp error_code
901 CFI_ENDPROC
902 END(coprocessor_error)
904 ENTRY(simd_coprocessor_error)
905 RING0_INT_FRAME
906 pushl $0
907 CFI_ADJUST_CFA_OFFSET 4
908 pushl $do_simd_coprocessor_error
909 CFI_ADJUST_CFA_OFFSET 4
910 jmp error_code
911 CFI_ENDPROC
912 END(simd_coprocessor_error)
914 ENTRY(device_not_available)
915 RING0_INT_FRAME
916 pushl $-1 # mark this as an int
917 CFI_ADJUST_CFA_OFFSET 4
918 pushl $do_device_not_available
919 CFI_ADJUST_CFA_OFFSET 4
920 jmp error_code
921 CFI_ENDPROC
922 END(device_not_available)
924 #ifdef CONFIG_PARAVIRT
925 ENTRY(native_iret)
926 iret
927 .section __ex_table,"a"
928 .align 4
929 .long native_iret, iret_exc
930 .previous
931 END(native_iret)
933 ENTRY(native_irq_enable_sysexit)
934 sti
935 sysexit
936 END(native_irq_enable_sysexit)
937 #endif
939 ENTRY(overflow)
940 RING0_INT_FRAME
941 pushl $0
942 CFI_ADJUST_CFA_OFFSET 4
943 pushl $do_overflow
944 CFI_ADJUST_CFA_OFFSET 4
945 jmp error_code
946 CFI_ENDPROC
947 END(overflow)
949 ENTRY(bounds)
950 RING0_INT_FRAME
951 pushl $0
952 CFI_ADJUST_CFA_OFFSET 4
953 pushl $do_bounds
954 CFI_ADJUST_CFA_OFFSET 4
955 jmp error_code
956 CFI_ENDPROC
957 END(bounds)
959 ENTRY(invalid_op)
960 RING0_INT_FRAME
961 pushl $0
962 CFI_ADJUST_CFA_OFFSET 4
963 pushl $do_invalid_op
964 CFI_ADJUST_CFA_OFFSET 4
965 jmp error_code
966 CFI_ENDPROC
967 END(invalid_op)
969 ENTRY(coprocessor_segment_overrun)
970 RING0_INT_FRAME
971 pushl $0
972 CFI_ADJUST_CFA_OFFSET 4
973 pushl $do_coprocessor_segment_overrun
974 CFI_ADJUST_CFA_OFFSET 4
975 jmp error_code
976 CFI_ENDPROC
977 END(coprocessor_segment_overrun)
979 ENTRY(invalid_TSS)
980 RING0_EC_FRAME
981 pushl $do_invalid_TSS
982 CFI_ADJUST_CFA_OFFSET 4
983 jmp error_code
984 CFI_ENDPROC
985 END(invalid_TSS)
987 ENTRY(segment_not_present)
988 RING0_EC_FRAME
989 pushl $do_segment_not_present
990 CFI_ADJUST_CFA_OFFSET 4
991 jmp error_code
992 CFI_ENDPROC
993 END(segment_not_present)
995 ENTRY(stack_segment)
996 RING0_EC_FRAME
997 pushl $do_stack_segment
998 CFI_ADJUST_CFA_OFFSET 4
999 jmp error_code
1000 CFI_ENDPROC
1001 END(stack_segment)
1003 ENTRY(alignment_check)
1004 RING0_EC_FRAME
1005 pushl $do_alignment_check
1006 CFI_ADJUST_CFA_OFFSET 4
1007 jmp error_code
1008 CFI_ENDPROC
1009 END(alignment_check)
1011 ENTRY(divide_error)
1012 RING0_INT_FRAME
1013 pushl $0 # no error code
1014 CFI_ADJUST_CFA_OFFSET 4
1015 pushl $do_divide_error
1016 CFI_ADJUST_CFA_OFFSET 4
1017 jmp error_code
1018 CFI_ENDPROC
1019 END(divide_error)
1021 #ifdef CONFIG_X86_MCE
1022 ENTRY(machine_check)
1023 RING0_INT_FRAME
1024 pushl $0
1025 CFI_ADJUST_CFA_OFFSET 4
1026 pushl machine_check_vector
1027 CFI_ADJUST_CFA_OFFSET 4
1028 jmp error_code
1029 CFI_ENDPROC
1030 END(machine_check)
1031 #endif
1033 ENTRY(spurious_interrupt_bug)
1034 RING0_INT_FRAME
1035 pushl $0
1036 CFI_ADJUST_CFA_OFFSET 4
1037 pushl $do_spurious_interrupt_bug
1038 CFI_ADJUST_CFA_OFFSET 4
1039 jmp error_code
1040 CFI_ENDPROC
1041 END(spurious_interrupt_bug)
1042 /*
1043 * End of kprobes section
1044 */
1045 .popsection
1047 ENTRY(kernel_thread_helper)
1048 pushl $0 # fake return address for unwinder
1049 CFI_STARTPROC
1050 movl %edi,%eax
1051 call *%esi
1052 call do_exit
1053 ud2 # padding for call trace
1054 CFI_ENDPROC
1055 ENDPROC(kernel_thread_helper)
1057 #ifdef CONFIG_XEN
1058 /* Xen doesn't set %esp to be precisely what the normal sysenter
1059 entrypoint expects, so fix it up before using the normal path. */
1060 ENTRY(xen_sysenter_target)
1061 RING0_INT_FRAME
1062 addl $5*4, %esp /* remove xen-provided frame */
1063 CFI_ADJUST_CFA_OFFSET -5*4
1064 jmp sysenter_past_esp
1065 CFI_ENDPROC
1067 ENTRY(xen_hypervisor_callback)
1068 CFI_STARTPROC
1069 pushl $0
1070 CFI_ADJUST_CFA_OFFSET 4
1071 SAVE_ALL
1072 TRACE_IRQS_OFF
1074 /* Check to see if we got the event in the critical
1075 region in xen_iret_direct, after we've reenabled
1076 events and checked for pending events. This simulates
1077 iret instruction's behaviour where it delivers a
1078 pending interrupt when enabling interrupts. */
1079 movl PT_EIP(%esp),%eax
1080 cmpl $xen_iret_start_crit,%eax
1081 jb 1f
1082 cmpl $xen_iret_end_crit,%eax
1083 jae 1f
1085 jmp xen_iret_crit_fixup
1087 ENTRY(xen_do_upcall)
1088 1: mov %esp, %eax
1089 call xen_evtchn_do_upcall
1090 jmp ret_from_intr
1091 CFI_ENDPROC
1092 ENDPROC(xen_hypervisor_callback)
1094 # Hypervisor uses this for application faults while it executes.
1095 # We get here for two reasons:
1096 # 1. Fault while reloading DS, ES, FS or GS
1097 # 2. Fault while executing IRET
1098 # Category 1 we fix up by reattempting the load, and zeroing the segment
1099 # register if the load fails.
1100 # Category 2 we fix up by jumping to do_iret_error. We cannot use the
1101 # normal Linux return path in this case because if we use the IRET hypercall
1102 # to pop the stack frame we end up in an infinite loop of failsafe callbacks.
1103 # We distinguish between categories by maintaining a status value in EAX.
1104 ENTRY(xen_failsafe_callback)
1105 CFI_STARTPROC
1106 pushl %eax
1107 CFI_ADJUST_CFA_OFFSET 4
1108 movl $1,%eax
1109 1: mov 4(%esp),%ds
1110 2: mov 8(%esp),%es
1111 3: mov 12(%esp),%fs
1112 4: mov 16(%esp),%gs
1113 testl %eax,%eax
1114 popl %eax
1115 CFI_ADJUST_CFA_OFFSET -4
1116 lea 16(%esp),%esp
1117 CFI_ADJUST_CFA_OFFSET -16
1118 jz 5f
1119 addl $16,%esp
1120 jmp iret_exc # EAX != 0 => Category 2 (Bad IRET)
1121 5: pushl $0 # EAX == 0 => Category 1 (Bad segment)
1122 CFI_ADJUST_CFA_OFFSET 4
1123 SAVE_ALL
1124 jmp ret_from_exception
1125 CFI_ENDPROC
1127 .section .fixup,"ax"
1128 6: xorl %eax,%eax
1129 movl %eax,4(%esp)
1130 jmp 1b
1131 7: xorl %eax,%eax
1132 movl %eax,8(%esp)
1133 jmp 2b
1134 8: xorl %eax,%eax
1135 movl %eax,12(%esp)
1136 jmp 3b
1137 9: xorl %eax,%eax
1138 movl %eax,16(%esp)
1139 jmp 4b
1140 .previous
1141 .section __ex_table,"a"
1142 .align 4
1143 .long 1b,6b
1144 .long 2b,7b
1145 .long 3b,8b
1146 .long 4b,9b
1147 .previous
1148 ENDPROC(xen_failsafe_callback)
1150 #endif /* CONFIG_XEN */
1152 #ifdef CONFIG_FUNCTION_TRACER
1153 #ifdef CONFIG_DYNAMIC_FTRACE
1155 ENTRY(mcount)
1156 ret
1157 END(mcount)
1159 ENTRY(ftrace_caller)
1160 cmpl $0, function_trace_stop
1161 jne ftrace_stub
1163 pushl %eax
1164 pushl %ecx
1165 pushl %edx
1166 movl 0xc(%esp), %eax
1167 movl 0x4(%ebp), %edx
1168 subl $MCOUNT_INSN_SIZE, %eax
1170 .globl ftrace_call
1171 ftrace_call:
1172 call ftrace_stub
1174 popl %edx
1175 popl %ecx
1176 popl %eax
1177 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1178 .globl ftrace_graph_call
1179 ftrace_graph_call:
1180 jmp ftrace_stub
1181 #endif
1183 .globl ftrace_stub
1184 ftrace_stub:
1185 ret
1186 END(ftrace_caller)
1188 #else /* ! CONFIG_DYNAMIC_FTRACE */
1190 ENTRY(mcount)
1191 cmpl $0, function_trace_stop
1192 jne ftrace_stub
1194 cmpl $ftrace_stub, ftrace_trace_function
1195 jnz trace
1196 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1197 cmpl $ftrace_stub, ftrace_graph_return
1198 jnz ftrace_graph_caller
1200 cmpl $ftrace_graph_entry_stub, ftrace_graph_entry
1201 jnz ftrace_graph_caller
1202 #endif
1203 .globl ftrace_stub
1204 ftrace_stub:
1205 ret
1207 /* taken from glibc */
1208 trace:
1209 pushl %eax
1210 pushl %ecx
1211 pushl %edx
1212 movl 0xc(%esp), %eax
1213 movl 0x4(%ebp), %edx
1214 subl $MCOUNT_INSN_SIZE, %eax
1216 call *ftrace_trace_function
1218 popl %edx
1219 popl %ecx
1220 popl %eax
1221 jmp ftrace_stub
1222 END(mcount)
1223 #endif /* CONFIG_DYNAMIC_FTRACE */
1224 #endif /* CONFIG_FUNCTION_TRACER */
1226 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1227 ENTRY(ftrace_graph_caller)
1228 cmpl $0, function_trace_stop
1229 jne ftrace_stub
1231 pushl %eax
1232 pushl %ecx
1233 pushl %edx
1234 movl 0xc(%esp), %edx
1235 lea 0x4(%ebp), %eax
1236 movl (%ebp), %ecx
1237 subl $MCOUNT_INSN_SIZE, %edx
1238 call prepare_ftrace_return
1239 popl %edx
1240 popl %ecx
1241 popl %eax
1242 ret
1243 END(ftrace_graph_caller)
1245 .globl return_to_handler
1246 return_to_handler:
1247 pushl %eax
1248 pushl %edx
1249 movl %ebp, %eax
1250 call ftrace_return_to_handler
1251 movl %eax, %ecx
1252 popl %edx
1253 popl %eax
1254 jmp *%ecx
1255 #endif
1257 .section .rodata,"a"
1258 #include "syscall_table_32.S"
1260 syscall_table_size=(.-sys_call_table)
1262 /*
1263 * Some functions should be protected against kprobes
1264 */
1265 .pushsection .kprobes.text, "ax"
1267 ENTRY(page_fault)
1268 RING0_EC_FRAME
1269 pushl $do_page_fault
1270 CFI_ADJUST_CFA_OFFSET 4
1271 ALIGN
1272 error_code:
1273 /* the function address is in %gs's slot on the stack */
1274 pushl %fs
1275 CFI_ADJUST_CFA_OFFSET 4
1276 /*CFI_REL_OFFSET fs, 0*/
1277 pushl %es
1278 CFI_ADJUST_CFA_OFFSET 4
1279 /*CFI_REL_OFFSET es, 0*/
1280 pushl %ds
1281 CFI_ADJUST_CFA_OFFSET 4
1282 /*CFI_REL_OFFSET ds, 0*/
1283 pushl %eax
1284 CFI_ADJUST_CFA_OFFSET 4
1285 CFI_REL_OFFSET eax, 0
1286 pushl %ebp
1287 CFI_ADJUST_CFA_OFFSET 4
1288 CFI_REL_OFFSET ebp, 0
1289 pushl %edi
1290 CFI_ADJUST_CFA_OFFSET 4
1291 CFI_REL_OFFSET edi, 0
1292 pushl %esi
1293 CFI_ADJUST_CFA_OFFSET 4
1294 CFI_REL_OFFSET esi, 0
1295 pushl %edx
1296 CFI_ADJUST_CFA_OFFSET 4
1297 CFI_REL_OFFSET edx, 0
1298 pushl %ecx
1299 CFI_ADJUST_CFA_OFFSET 4
1300 CFI_REL_OFFSET ecx, 0
1301 pushl %ebx
1302 CFI_ADJUST_CFA_OFFSET 4
1303 CFI_REL_OFFSET ebx, 0
1304 cld
1305 movl $(__KERNEL_PERCPU), %ecx
1306 movl %ecx, %fs
1307 UNWIND_ESPFIX_STACK
1308 GS_TO_REG %ecx
1309 movl PT_GS(%esp), %edi # get the function address
1310 movl PT_ORIG_EAX(%esp), %edx # get the error code
1311 movl $-1, PT_ORIG_EAX(%esp) # no syscall to restart
1312 REG_TO_PTGS %ecx
1313 SET_KERNEL_GS %ecx
1314 movl $(__USER_DS), %ecx
1315 movl %ecx, %ds
1316 movl %ecx, %es
1317 TRACE_IRQS_OFF
1318 movl %esp,%eax # pt_regs pointer
1319 call *%edi
1320 jmp ret_from_exception
1321 CFI_ENDPROC
1322 END(page_fault)
1324 /*
1325 * Debug traps and NMI can happen at the one SYSENTER instruction
1326 * that sets up the real kernel stack. Check here, since we can't
1327 * allow the wrong stack to be used.
1328 *
1329 * "TSS_sysenter_sp0+12" is because the NMI/debug handler will have
1330 * already pushed 3 words if it hits on the sysenter instruction:
1331 * eflags, cs and eip.
1332 *
1333 * We just load the right stack, and push the three (known) values
1334 * by hand onto the new stack - while updating the return eip past
1335 * the instruction that would have done it for sysenter.
1336 */
1337 .macro FIX_STACK offset ok label
1338 cmpw $__KERNEL_CS, 4(%esp)
1339 jne \ok
1340 \label:
1341 movl TSS_sysenter_sp0 + \offset(%esp), %esp
1342 CFI_DEF_CFA esp, 0
1343 CFI_UNDEFINED eip
1344 pushfl
1345 CFI_ADJUST_CFA_OFFSET 4
1346 pushl $__KERNEL_CS
1347 CFI_ADJUST_CFA_OFFSET 4
1348 pushl $sysenter_past_esp
1349 CFI_ADJUST_CFA_OFFSET 4
1350 CFI_REL_OFFSET eip, 0
1351 .endm
1353 ENTRY(debug)
1354 RING0_INT_FRAME
1355 cmpl $ia32_sysenter_target,(%esp)
1356 jne debug_stack_correct
1357 FIX_STACK 12, debug_stack_correct, debug_esp_fix_insn
1358 debug_stack_correct:
1359 pushl $-1 # mark this as an int
1360 CFI_ADJUST_CFA_OFFSET 4
1361 SAVE_ALL
1362 TRACE_IRQS_OFF
1363 xorl %edx,%edx # error code 0
1364 movl %esp,%eax # pt_regs pointer
1365 call do_debug
1366 jmp ret_from_exception
1367 CFI_ENDPROC
1368 END(debug)
1370 /*
1371 * NMI is doubly nasty. It can happen _while_ we're handling
1372 * a debug fault, and the debug fault hasn't yet been able to
1373 * clear up the stack. So we first check whether we got an
1374 * NMI on the sysenter entry path, but after that we need to
1375 * check whether we got an NMI on the debug path where the debug
1376 * fault happened on the sysenter path.
1377 */
1378 ENTRY(nmi)
1379 RING0_INT_FRAME
1380 pushl %eax
1381 CFI_ADJUST_CFA_OFFSET 4
1382 movl %ss, %eax
1383 cmpw $__ESPFIX_SS, %ax
1384 popl %eax
1385 CFI_ADJUST_CFA_OFFSET -4
1386 je nmi_espfix_stack
1387 cmpl $ia32_sysenter_target,(%esp)
1388 je nmi_stack_fixup
1389 pushl %eax
1390 CFI_ADJUST_CFA_OFFSET 4
1391 movl %esp,%eax
1392 /* Do not access memory above the end of our stack page,
1393 * it might not exist.
1394 */
1395 andl $(THREAD_SIZE-1),%eax
1396 cmpl $(THREAD_SIZE-20),%eax
1397 popl %eax
1398 CFI_ADJUST_CFA_OFFSET -4
1399 jae nmi_stack_correct
1400 cmpl $ia32_sysenter_target,12(%esp)
1401 je nmi_debug_stack_check
1402 nmi_stack_correct:
1403 /* We have a RING0_INT_FRAME here */
1404 pushl %eax
1405 CFI_ADJUST_CFA_OFFSET 4
1406 SAVE_ALL
1407 xorl %edx,%edx # zero error code
1408 movl %esp,%eax # pt_regs pointer
1409 call do_nmi
1410 jmp restore_all_notrace
1411 CFI_ENDPROC
1413 nmi_stack_fixup:
1414 RING0_INT_FRAME
1415 FIX_STACK 12, nmi_stack_correct, 1
1416 jmp nmi_stack_correct
1418 nmi_debug_stack_check:
1419 /* We have a RING0_INT_FRAME here */
1420 cmpw $__KERNEL_CS,16(%esp)
1421 jne nmi_stack_correct
1422 cmpl $debug,(%esp)
1423 jb nmi_stack_correct
1424 cmpl $debug_esp_fix_insn,(%esp)
1425 ja nmi_stack_correct
1426 FIX_STACK 24, nmi_stack_correct, 1
1427 jmp nmi_stack_correct
1429 nmi_espfix_stack:
1430 /* We have a RING0_INT_FRAME here.
1431 *
1432 * create the pointer to lss back
1433 */
1434 pushl %ss
1435 CFI_ADJUST_CFA_OFFSET 4
1436 pushl %esp
1437 CFI_ADJUST_CFA_OFFSET 4
1438 addl $4, (%esp)
1439 /* copy the iret frame of 12 bytes */
1440 .rept 3
1441 pushl 16(%esp)
1442 CFI_ADJUST_CFA_OFFSET 4
1443 .endr
1444 pushl %eax
1445 CFI_ADJUST_CFA_OFFSET 4
1446 SAVE_ALL
1447 FIXUP_ESPFIX_STACK # %eax == %esp
1448 xorl %edx,%edx # zero error code
1449 call do_nmi
1450 RESTORE_REGS
1451 lss 12+4(%esp), %esp # back to espfix stack
1452 CFI_ADJUST_CFA_OFFSET -24
1453 jmp irq_return
1454 CFI_ENDPROC
1455 END(nmi)
1457 ENTRY(int3)
1458 RING0_INT_FRAME
1459 pushl $-1 # mark this as an int
1460 CFI_ADJUST_CFA_OFFSET 4
1461 SAVE_ALL
1462 TRACE_IRQS_OFF
1463 xorl %edx,%edx # zero error code
1464 movl %esp,%eax # pt_regs pointer
1465 call do_int3
1466 jmp ret_from_exception
1467 CFI_ENDPROC
1468 END(int3)
1470 ENTRY(general_protection)
1471 RING0_EC_FRAME
1472 pushl $do_general_protection
1473 CFI_ADJUST_CFA_OFFSET 4
1474 jmp error_code
1475 CFI_ENDPROC
1476 END(general_protection)
1478 /*
1479 * End of kprobes section
1480 */
1481 .popsection