3 * Copyright (C) 1991, 1992 Linus Torvalds
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.
11 * NOTE: This code handles signal-recognition, which happens every time
12 * after a timer-interrupt and after each system call.
14 * I changed all the .align's to 4 (16 byte alignment), as that's faster
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
33 * 28(%esp) - %gs saved iff !CONFIG_X86_32_LAZY_GS
41 * "current" is in register %ebx during any slow entries.
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>
50 #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>
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
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").
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.
81 #define nr_syscalls ((syscall_table_size)/4)
84 #define preempt_stop(clobbers) DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF
86 #define preempt_stop(clobbers)
87 #define resume_kernel restore_all
90 .macro TRACE_IRQS_IRET
91 #ifdef CONFIG_TRACE_IRQFLAGS
92 testl $X86_EFLAGS_IF,PT_EFLAGS(%esp) # interrupts off?
100 #define resume_userspace_sig check_userspace
102 #define resume_userspace_sig resume_userspace
106 * User gs save/restore
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.
112 * Local labels 98 and 99 are used.
114 #ifdef CONFIG_X86_32_LAZY_GS
116 /* unfortunately push/pop can't be no-op */
119 CFI_ADJUST_CFA_OFFSET 4
122 addl $(4 + \pop), %esp
123 CFI_ADJUST_CFA_OFFSET -(4 + \pop)
128 /* all the rest are no-op */
135 .macro REG_TO_PTGS reg
137 .macro SET_KERNEL_GS reg
140 #else /* CONFIG_X86_32_LAZY_GS */
144 CFI_ADJUST_CFA_OFFSET 4
145 /*CFI_REL_OFFSET gs, 0*/
150 CFI_ADJUST_CFA_OFFSET -4
154 CFI_ADJUST_CFA_OFFSET -\pop
158 .pushsection .fixup, "ax"
161 .section __ex_table, "a"
168 98: mov PT_GS(%esp), %gs
171 .pushsection .fixup, "ax"
172 99: movl $0, PT_GS(%esp)
174 .section __ex_table, "a"
182 /*CFI_REGISTER gs, \reg*/
184 .macro REG_TO_PTGS reg
185 movl \reg, PT_GS(%esp)
186 /*CFI_REL_OFFSET gs, PT_GS*/
188 .macro SET_KERNEL_GS reg
189 movl $(__KERNEL_STACK_CANARY), \reg
193 #endif /* CONFIG_X86_32_LAZY_GS */
199 CFI_ADJUST_CFA_OFFSET 4
200 /*CFI_REL_OFFSET fs, 0;*/
202 CFI_ADJUST_CFA_OFFSET 4
203 /*CFI_REL_OFFSET es, 0;*/
205 CFI_ADJUST_CFA_OFFSET 4
206 /*CFI_REL_OFFSET ds, 0;*/
208 CFI_ADJUST_CFA_OFFSET 4
209 CFI_REL_OFFSET eax, 0
211 CFI_ADJUST_CFA_OFFSET 4
212 CFI_REL_OFFSET ebp, 0
214 CFI_ADJUST_CFA_OFFSET 4
215 CFI_REL_OFFSET edi, 0
217 CFI_ADJUST_CFA_OFFSET 4
218 CFI_REL_OFFSET esi, 0
220 CFI_ADJUST_CFA_OFFSET 4
221 CFI_REL_OFFSET edx, 0
223 CFI_ADJUST_CFA_OFFSET 4
224 CFI_REL_OFFSET ecx, 0
226 CFI_ADJUST_CFA_OFFSET 4
227 CFI_REL_OFFSET ebx, 0
228 movl $(__USER_DS), %edx
231 movl $(__KERNEL_PERCPU), %edx
236 .macro RESTORE_INT_REGS
238 CFI_ADJUST_CFA_OFFSET -4
241 CFI_ADJUST_CFA_OFFSET -4
244 CFI_ADJUST_CFA_OFFSET -4
247 CFI_ADJUST_CFA_OFFSET -4
250 CFI_ADJUST_CFA_OFFSET -4
253 CFI_ADJUST_CFA_OFFSET -4
256 CFI_ADJUST_CFA_OFFSET -4
260 .macro RESTORE_REGS pop=0
263 CFI_ADJUST_CFA_OFFSET -4
266 CFI_ADJUST_CFA_OFFSET -4
269 CFI_ADJUST_CFA_OFFSET -4
272 .pushsection .fixup, "ax"
279 .section __ex_table, "a"
288 .macro RING0_INT_FRAME
292 /*CFI_OFFSET cs, -2*4;*/
296 .macro RING0_EC_FRAME
300 /*CFI_OFFSET cs, -2*4;*/
304 .macro RING0_PTREGS_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
324 CFI_ADJUST_CFA_OFFSET 4
326 GET_THREAD_INFO(%ebp)
328 CFI_ADJUST_CFA_OFFSET -4
329 pushl $0x0202 # Reset kernel eflags
330 CFI_ADJUST_CFA_OFFSET 4
332 CFI_ADJUST_CFA_OFFSET -4
338 * Return to user mode is not as complex as all this looks,
339 * but we want the default path for a system call return to
340 * go as quickly as possible which is why some of this is
341 * less clear than it otherwise should be.
344 # userspace resumption stub bypassing syscall exit tracing
348 preempt_stop(CLBR_ANY)
350 GET_THREAD_INFO(%ebp)
352 movl PT_EFLAGS(%esp), %eax # mix EFLAGS and CS
353 movb PT_CS(%esp), %al
354 andl $(X86_EFLAGS_VM | SEGMENT_RPL_MASK), %eax
356 jb resume_kernel # not returning to v8086 or userspace
358 ENTRY(resume_userspace)
360 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
361 # setting need_resched or sigpending
362 # between sampling and the iret
364 movl TI_flags(%ebp), %ecx
365 andl $_TIF_WORK_MASK, %ecx # is there any work to be done on
366 # int/exception return?
369 END(ret_from_exception)
371 #ifdef CONFIG_PREEMPT
373 DISABLE_INTERRUPTS(CLBR_ANY)
374 cmpl $0,TI_preempt_count(%ebp) # non-zero preempt_count ?
377 movl TI_flags(%ebp), %ecx # need_resched set ?
378 testb $_TIF_NEED_RESCHED, %cl
380 testl $X86_EFLAGS_IF,PT_EFLAGS(%esp) # interrupts off (exception path) ?
382 call preempt_schedule_irq
388 /* SYSENTER_RETURN points to after the "sysenter" instruction in
389 the vsyscall page. See vsyscall-sysentry.S, which defines the symbol. */
391 # sysenter call handler stub
392 ENTRY(ia32_sysenter_target)
396 CFI_REGISTER esp, ebp
397 movl TSS_sysenter_sp0(%esp),%esp
400 * Interrupts are disabled here, but we can't trace it until
401 * enough kernel state to call TRACE_IRQS_OFF can be called - but
402 * we immediately enable interrupts at that point anyway.
405 CFI_ADJUST_CFA_OFFSET 4
406 /*CFI_REL_OFFSET ss, 0*/
408 CFI_ADJUST_CFA_OFFSET 4
409 CFI_REL_OFFSET esp, 0
411 orl $X86_EFLAGS_IF, (%esp)
412 CFI_ADJUST_CFA_OFFSET 4
414 CFI_ADJUST_CFA_OFFSET 4
415 /*CFI_REL_OFFSET cs, 0*/
417 * Push current_thread_info()->sysenter_return to the stack.
418 * A tiny bit of offset fixup is necessary - 4*4 means the 4 words
419 * pushed above; +8 corresponds to copy_thread's esp0 setting.
421 pushl (TI_sysenter_return-THREAD_SIZE+8+4*4)(%esp)
422 CFI_ADJUST_CFA_OFFSET 4
423 CFI_REL_OFFSET eip, 0
426 CFI_ADJUST_CFA_OFFSET 4
428 ENABLE_INTERRUPTS(CLBR_NONE)
431 * Load the potential sixth argument from user stack.
432 * Careful about security.
434 cmpl $__PAGE_OFFSET-3,%ebp
437 movl %ebp,PT_EBP(%esp)
438 .section __ex_table,"a"
440 .long 1b,syscall_fault
443 GET_THREAD_INFO(%ebp)
445 testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%ebp)
448 cmpl $(nr_syscalls), %eax
450 call *sys_call_table(,%eax,4)
451 movl %eax,PT_EAX(%esp)
453 DISABLE_INTERRUPTS(CLBR_ANY)
455 movl TI_flags(%ebp), %ecx
456 testl $_TIF_ALLWORK_MASK, %ecx
459 /* if something modifies registers it must also disable sysexit */
460 movl PT_EIP(%esp), %edx
461 movl PT_OLDESP(%esp), %ecx
464 1: mov PT_FS(%esp), %fs
466 ENABLE_INTERRUPTS_SYSEXIT
468 #ifdef CONFIG_AUDITSYSCALL
470 testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
471 jnz syscall_trace_entry
473 CFI_ADJUST_CFA_OFFSET -4
474 /* %esi already in 8(%esp) 6th arg: 4th syscall arg */
475 /* %edx already in 4(%esp) 5th arg: 3rd syscall arg */
476 /* %ecx already in 0(%esp) 4th arg: 2nd syscall arg */
477 movl %ebx,%ecx /* 3rd arg: 1st syscall arg */
478 movl %eax,%edx /* 2nd arg: syscall number */
479 movl $AUDIT_ARCH_I386,%eax /* 1st arg: audit arch */
480 call audit_syscall_entry
482 CFI_ADJUST_CFA_OFFSET 4
483 movl PT_EAX(%esp),%eax /* reload syscall number */
487 testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %ecx
488 jne syscall_exit_work
490 ENABLE_INTERRUPTS(CLBR_ANY)
491 movl %eax,%edx /* second arg, syscall return value */
492 cmpl $0,%eax /* is it < 0? */
493 setl %al /* 1 if so, 0 if not */
494 movzbl %al,%eax /* zero-extend that */
495 inc %eax /* first arg, 0->1(AUDITSC_SUCCESS), 1->2(AUDITSC_FAILURE) */
496 call audit_syscall_exit
497 DISABLE_INTERRUPTS(CLBR_ANY)
499 movl TI_flags(%ebp), %ecx
500 testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %ecx
501 jne syscall_exit_work
502 movl PT_EAX(%esp),%eax /* reload syscall return value */
507 .pushsection .fixup,"ax"
508 2: movl $0,PT_FS(%esp)
510 .section __ex_table,"a"
515 ENDPROC(ia32_sysenter_target)
517 # system call handler stub
519 RING0_INT_FRAME # can't unwind into user space anyway
520 pushl %eax # save orig_eax
521 CFI_ADJUST_CFA_OFFSET 4
523 GET_THREAD_INFO(%ebp)
524 # system call tracing in operation / emulation
525 testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%ebp)
526 jnz syscall_trace_entry
527 cmpl $(nr_syscalls), %eax
530 call *sys_call_table(,%eax,4)
531 movl %eax,PT_EAX(%esp) # store the return value
534 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
535 # setting need_resched or sigpending
536 # between sampling and the iret
538 movl TI_flags(%ebp), %ecx
539 testl $_TIF_ALLWORK_MASK, %ecx # current->work
540 jne syscall_exit_work
545 movl PT_EFLAGS(%esp), %eax # mix EFLAGS, SS and CS
546 # Warning: PT_OLDSS(%esp) contains the wrong/random values if we
547 # are returning to the kernel.
548 # See comments in process.c:copy_thread() for details.
549 movb PT_OLDSS(%esp), %ah
550 movb PT_CS(%esp), %al
551 andl $(X86_EFLAGS_VM | (SEGMENT_TI_MASK << 8) | SEGMENT_RPL_MASK), %eax
552 cmpl $((SEGMENT_LDT << 8) | USER_RPL), %eax
554 je ldt_ss # returning to user-space with LDT SS
556 RESTORE_REGS 4 # skip orig_eax/error_code
557 CFI_ADJUST_CFA_OFFSET -4
562 pushl $0 # no error code
566 .section __ex_table,"a"
568 .long irq_return,iret_exc
573 larl PT_OLDSS(%esp), %eax
575 testl $0x00400000, %eax # returning to 32bit stack?
576 jnz restore_nocheck # allright, normal return
578 #ifdef CONFIG_PARAVIRT
580 * The kernel can't run on a non-flat stack if paravirt mode
581 * is active. Rather than try to fixup the high bits of
582 * ESP, bypass this code entirely. This may break DOSemu
583 * and/or Wine support in a paravirt VM, although the option
584 * is still available to implement the setting of the high
585 * 16-bits in the INTERRUPT_RETURN paravirt-op.
587 cmpl $0, pv_info+PARAVIRT_enabled
592 * Setup and switch to ESPFIX stack
594 * We're returning to userspace with a 16 bit stack. The CPU will not
595 * restore the high word of ESP for us on executing iret... This is an
596 * "official" bug of all the x86-compatible CPUs, which we can work
597 * around to make dosemu and wine happy. We do this by preloading the
598 * high word of ESP with the high word of the userspace ESP while
599 * compensating for the offset by changing to the ESPFIX segment with
600 * a base address that matches for the difference.
602 mov %esp, %edx /* load kernel esp */
603 mov PT_OLDESP(%esp), %eax /* load userspace esp */
604 mov %dx, %ax /* eax: new kernel esp */
605 sub %eax, %edx /* offset (low word is 0) */
606 PER_CPU(gdt_page, %ebx)
608 mov %dl, GDT_ENTRY_ESPFIX_SS * 8 + 4(%ebx) /* bits 16..23 */
609 mov %dh, GDT_ENTRY_ESPFIX_SS * 8 + 7(%ebx) /* bits 24..31 */
611 CFI_ADJUST_CFA_OFFSET 4
612 push %eax /* new kernel esp */
613 CFI_ADJUST_CFA_OFFSET 4
614 /* Disable interrupts, but do not irqtrace this section: we
615 * will soon execute iret and the tracer was already set to
616 * the irqstate after the iret */
617 DISABLE_INTERRUPTS(CLBR_EAX)
618 lss (%esp), %esp /* switch to espfix segment */
619 CFI_ADJUST_CFA_OFFSET -8
624 # perform work that needs to be done immediately before resumption
626 RING0_PTREGS_FRAME # can't unwind into user space anyway
628 testb $_TIF_NEED_RESCHED, %cl
633 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
634 # setting need_resched or sigpending
635 # between sampling and the iret
637 movl TI_flags(%ebp), %ecx
638 andl $_TIF_WORK_MASK, %ecx # is there any work to be done other
639 # than syscall tracing?
641 testb $_TIF_NEED_RESCHED, %cl
644 work_notifysig: # deal with pending signals and
645 # notify-resume requests
647 testl $X86_EFLAGS_VM, PT_EFLAGS(%esp)
649 jne work_notifysig_v86 # returning to kernel-space or
652 call do_notify_resume
653 jmp resume_userspace_sig
657 pushl %ecx # save ti_flags for do_notify_resume
658 CFI_ADJUST_CFA_OFFSET 4
659 call save_v86_state # %eax contains pt_regs pointer
661 CFI_ADJUST_CFA_OFFSET -4
667 call do_notify_resume
668 jmp resume_userspace_sig
671 # perform syscall exit tracing
674 movl $-ENOSYS,PT_EAX(%esp)
676 call syscall_trace_enter
677 /* What it returned is what we'll actually use. */
678 cmpl $(nr_syscalls), %eax
681 END(syscall_trace_entry)
683 # perform syscall exit tracing
686 testl $_TIF_WORK_SYSCALL_EXIT, %ecx
689 ENABLE_INTERRUPTS(CLBR_ANY) # could let syscall_trace_leave() call
692 call syscall_trace_leave
694 END(syscall_exit_work)
697 RING0_INT_FRAME # can't unwind into user space anyway
699 GET_THREAD_INFO(%ebp)
700 movl $-EFAULT,PT_EAX(%esp)
705 movl $-ENOSYS,PT_EAX(%esp)
711 * System calls that need a pt_regs pointer.
713 #define PTREGSCALL(name) \
724 PTREGSCALL(sigaltstack)
725 PTREGSCALL(sigreturn)
726 PTREGSCALL(rt_sigreturn)
730 .macro FIXUP_ESPFIX_STACK
732 * Switch back for ESPFIX stack to the normal zerobased stack
734 * We can't call C functions using the ESPFIX stack. This code reads
735 * the high word of the segment base from the GDT and swiches to the
736 * normal stack and adjusts ESP with the matching offset.
738 /* fixup the stack */
739 PER_CPU(gdt_page, %ebx)
740 mov GDT_ENTRY_ESPFIX_SS * 8 + 4(%ebx), %al /* bits 16..23 */
741 mov GDT_ENTRY_ESPFIX_SS * 8 + 7(%ebx), %ah /* bits 24..31 */
743 addl %esp, %eax /* the adjusted stack pointer */
745 CFI_ADJUST_CFA_OFFSET 4
747 CFI_ADJUST_CFA_OFFSET 4
748 lss (%esp), %esp /* switch to the normal stack segment */
749 CFI_ADJUST_CFA_OFFSET -8
751 .macro UNWIND_ESPFIX_STACK
753 /* see if on espfix stack */
754 cmpw $__ESPFIX_SS, %ax
756 movl $__KERNEL_DS, %eax
759 /* switch to normal stack */
765 * Build the entry stubs and pointer table with some assembler magic.
766 * We pack 7 stubs into a single 32-byte chunk, which will fit in a
767 * single cache line on all modern x86 implementations.
769 .section .init.rodata,"a"
773 .p2align CONFIG_X86_L1_CACHE_SHIFT
774 ENTRY(irq_entries_start)
776 vector=FIRST_EXTERNAL_VECTOR
777 .rept (NR_VECTORS-FIRST_EXTERNAL_VECTOR+6)/7
780 .if vector < NR_VECTORS
781 .if vector <> FIRST_EXTERNAL_VECTOR
782 CFI_ADJUST_CFA_OFFSET -4
784 1: pushl $(~vector+0x80) /* Note: always in signed byte range */
785 CFI_ADJUST_CFA_OFFSET 4
786 .if ((vector-FIRST_EXTERNAL_VECTOR)%7) <> 6
795 2: jmp common_interrupt
797 END(irq_entries_start)
804 * the CPU automatically disables interrupts when executing an IRQ vector,
805 * so IRQ-flags tracing has to follow that:
807 .p2align CONFIG_X86_L1_CACHE_SHIFT
809 addl $-0x80,(%esp) /* Adjust vector into the [-256,-1] range */
815 ENDPROC(common_interrupt)
818 #define BUILD_INTERRUPT3(name, nr, fn) \
822 CFI_ADJUST_CFA_OFFSET 4; \
831 #define BUILD_INTERRUPT(name, nr) BUILD_INTERRUPT3(name, nr, smp_##name)
833 /* The include is where all of the SMP etc. interrupts come from */
834 #include <asm/entry_arch.h>
836 ENTRY(coprocessor_error)
839 CFI_ADJUST_CFA_OFFSET 4
840 pushl $do_coprocessor_error
841 CFI_ADJUST_CFA_OFFSET 4
844 END(coprocessor_error)
846 ENTRY(simd_coprocessor_error)
849 CFI_ADJUST_CFA_OFFSET 4
850 pushl $do_simd_coprocessor_error
851 CFI_ADJUST_CFA_OFFSET 4
854 END(simd_coprocessor_error)
856 ENTRY(device_not_available)
858 pushl $-1 # mark this as an int
859 CFI_ADJUST_CFA_OFFSET 4
860 pushl $do_device_not_available
861 CFI_ADJUST_CFA_OFFSET 4
864 END(device_not_available)
866 #ifdef CONFIG_PARAVIRT
869 .section __ex_table,"a"
871 .long native_iret, iret_exc
875 ENTRY(native_irq_enable_sysexit)
878 END(native_irq_enable_sysexit)
884 CFI_ADJUST_CFA_OFFSET 4
886 CFI_ADJUST_CFA_OFFSET 4
894 CFI_ADJUST_CFA_OFFSET 4
896 CFI_ADJUST_CFA_OFFSET 4
904 CFI_ADJUST_CFA_OFFSET 4
906 CFI_ADJUST_CFA_OFFSET 4
911 ENTRY(coprocessor_segment_overrun)
914 CFI_ADJUST_CFA_OFFSET 4
915 pushl $do_coprocessor_segment_overrun
916 CFI_ADJUST_CFA_OFFSET 4
919 END(coprocessor_segment_overrun)
923 pushl $do_invalid_TSS
924 CFI_ADJUST_CFA_OFFSET 4
929 ENTRY(segment_not_present)
931 pushl $do_segment_not_present
932 CFI_ADJUST_CFA_OFFSET 4
935 END(segment_not_present)
939 pushl $do_stack_segment
940 CFI_ADJUST_CFA_OFFSET 4
945 ENTRY(alignment_check)
947 pushl $do_alignment_check
948 CFI_ADJUST_CFA_OFFSET 4
955 pushl $0 # no error code
956 CFI_ADJUST_CFA_OFFSET 4
957 pushl $do_divide_error
958 CFI_ADJUST_CFA_OFFSET 4
963 #ifdef CONFIG_X86_MCE
967 CFI_ADJUST_CFA_OFFSET 4
968 pushl machine_check_vector
969 CFI_ADJUST_CFA_OFFSET 4
975 ENTRY(spurious_interrupt_bug)
978 CFI_ADJUST_CFA_OFFSET 4
979 pushl $do_spurious_interrupt_bug
980 CFI_ADJUST_CFA_OFFSET 4
983 END(spurious_interrupt_bug)
985 ENTRY(kernel_thread_helper)
986 pushl $0 # fake return address for unwinder
990 CFI_ADJUST_CFA_OFFSET 4
993 CFI_ADJUST_CFA_OFFSET 4
995 ud2 # padding for call trace
997 ENDPROC(kernel_thread_helper)
1000 /* Xen doesn't set %esp to be precisely what the normal sysenter
1001 entrypoint expects, so fix it up before using the normal path. */
1002 ENTRY(xen_sysenter_target)
1004 addl $5*4, %esp /* remove xen-provided frame */
1005 CFI_ADJUST_CFA_OFFSET -5*4
1006 jmp sysenter_past_esp
1009 ENTRY(xen_hypervisor_callback)
1012 CFI_ADJUST_CFA_OFFSET 4
1016 /* Check to see if we got the event in the critical
1017 region in xen_iret_direct, after we've reenabled
1018 events and checked for pending events. This simulates
1019 iret instruction's behaviour where it delivers a
1020 pending interrupt when enabling interrupts. */
1021 movl PT_EIP(%esp),%eax
1022 cmpl $xen_iret_start_crit,%eax
1024 cmpl $xen_iret_end_crit,%eax
1027 jmp xen_iret_crit_fixup
1029 ENTRY(xen_do_upcall)
1031 call xen_evtchn_do_upcall
1034 ENDPROC(xen_hypervisor_callback)
1036 # Hypervisor uses this for application faults while it executes.
1037 # We get here for two reasons:
1038 # 1. Fault while reloading DS, ES, FS or GS
1039 # 2. Fault while executing IRET
1040 # Category 1 we fix up by reattempting the load, and zeroing the segment
1041 # register if the load fails.
1042 # Category 2 we fix up by jumping to do_iret_error. We cannot use the
1043 # normal Linux return path in this case because if we use the IRET hypercall
1044 # to pop the stack frame we end up in an infinite loop of failsafe callbacks.
1045 # We distinguish between categories by maintaining a status value in EAX.
1046 ENTRY(xen_failsafe_callback)
1049 CFI_ADJUST_CFA_OFFSET 4
1057 CFI_ADJUST_CFA_OFFSET -4
1059 CFI_ADJUST_CFA_OFFSET -16
1062 jmp iret_exc # EAX != 0 => Category 2 (Bad IRET)
1063 5: pushl $0 # EAX == 0 => Category 1 (Bad segment)
1064 CFI_ADJUST_CFA_OFFSET 4
1066 jmp ret_from_exception
1069 .section .fixup,"ax"
1083 .section __ex_table,"a"
1090 ENDPROC(xen_failsafe_callback)
1092 #endif /* CONFIG_XEN */
1094 #ifdef CONFIG_FUNCTION_TRACER
1095 #ifdef CONFIG_DYNAMIC_FTRACE
1101 ENTRY(ftrace_caller)
1102 cmpl $0, function_trace_stop
1108 movl 0xc(%esp), %eax
1109 movl 0x4(%ebp), %edx
1110 subl $MCOUNT_INSN_SIZE, %eax
1119 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1120 .globl ftrace_graph_call
1130 #else /* ! CONFIG_DYNAMIC_FTRACE */
1133 cmpl $0, function_trace_stop
1136 cmpl $ftrace_stub, ftrace_trace_function
1138 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1139 cmpl $ftrace_stub, ftrace_graph_return
1140 jnz ftrace_graph_caller
1142 cmpl $ftrace_graph_entry_stub, ftrace_graph_entry
1143 jnz ftrace_graph_caller
1149 /* taken from glibc */
1154 movl 0xc(%esp), %eax
1155 movl 0x4(%ebp), %edx
1156 subl $MCOUNT_INSN_SIZE, %eax
1158 call *ftrace_trace_function
1165 #endif /* CONFIG_DYNAMIC_FTRACE */
1166 #endif /* CONFIG_FUNCTION_TRACER */
1168 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1169 ENTRY(ftrace_graph_caller)
1170 cmpl $0, function_trace_stop
1176 movl 0xc(%esp), %edx
1178 subl $MCOUNT_INSN_SIZE, %edx
1179 call prepare_ftrace_return
1184 END(ftrace_graph_caller)
1186 .globl return_to_handler
1192 call ftrace_return_to_handler
1193 movl %eax, 0xc(%esp)
1200 .section .rodata,"a"
1201 #include "syscall_table_32.S"
1203 syscall_table_size=(.-sys_call_table)
1206 * Some functions should be protected against kprobes
1208 .pushsection .kprobes.text, "ax"
1212 pushl $do_page_fault
1213 CFI_ADJUST_CFA_OFFSET 4
1216 /* the function address is in %gs's slot on the stack */
1218 CFI_ADJUST_CFA_OFFSET 4
1219 /*CFI_REL_OFFSET fs, 0*/
1221 CFI_ADJUST_CFA_OFFSET 4
1222 /*CFI_REL_OFFSET es, 0*/
1224 CFI_ADJUST_CFA_OFFSET 4
1225 /*CFI_REL_OFFSET ds, 0*/
1227 CFI_ADJUST_CFA_OFFSET 4
1228 CFI_REL_OFFSET eax, 0
1230 CFI_ADJUST_CFA_OFFSET 4
1231 CFI_REL_OFFSET ebp, 0
1233 CFI_ADJUST_CFA_OFFSET 4
1234 CFI_REL_OFFSET edi, 0
1236 CFI_ADJUST_CFA_OFFSET 4
1237 CFI_REL_OFFSET esi, 0
1239 CFI_ADJUST_CFA_OFFSET 4
1240 CFI_REL_OFFSET edx, 0
1242 CFI_ADJUST_CFA_OFFSET 4
1243 CFI_REL_OFFSET ecx, 0
1245 CFI_ADJUST_CFA_OFFSET 4
1246 CFI_REL_OFFSET ebx, 0
1248 movl $(__KERNEL_PERCPU), %ecx
1252 movl PT_GS(%esp), %edi # get the function address
1253 movl PT_ORIG_EAX(%esp), %edx # get the error code
1254 movl $-1, PT_ORIG_EAX(%esp) # no syscall to restart
1257 movl $(__USER_DS), %ecx
1261 movl %esp,%eax # pt_regs pointer
1263 jmp ret_from_exception
1268 * Debug traps and NMI can happen at the one SYSENTER instruction
1269 * that sets up the real kernel stack. Check here, since we can't
1270 * allow the wrong stack to be used.
1272 * "TSS_sysenter_sp0+12" is because the NMI/debug handler will have
1273 * already pushed 3 words if it hits on the sysenter instruction:
1274 * eflags, cs and eip.
1276 * We just load the right stack, and push the three (known) values
1277 * by hand onto the new stack - while updating the return eip past
1278 * the instruction that would have done it for sysenter.
1280 .macro FIX_STACK offset ok label
1281 cmpw $__KERNEL_CS, 4(%esp)
1284 movl TSS_sysenter_sp0 + \offset(%esp), %esp
1288 CFI_ADJUST_CFA_OFFSET 4
1290 CFI_ADJUST_CFA_OFFSET 4
1291 pushl $sysenter_past_esp
1292 CFI_ADJUST_CFA_OFFSET 4
1293 CFI_REL_OFFSET eip, 0
1298 cmpl $ia32_sysenter_target,(%esp)
1299 jne debug_stack_correct
1300 FIX_STACK 12, debug_stack_correct, debug_esp_fix_insn
1301 debug_stack_correct:
1302 pushl $-1 # mark this as an int
1303 CFI_ADJUST_CFA_OFFSET 4
1306 xorl %edx,%edx # error code 0
1307 movl %esp,%eax # pt_regs pointer
1309 jmp ret_from_exception
1314 * NMI is doubly nasty. It can happen _while_ we're handling
1315 * a debug fault, and the debug fault hasn't yet been able to
1316 * clear up the stack. So we first check whether we got an
1317 * NMI on the sysenter entry path, but after that we need to
1318 * check whether we got an NMI on the debug path where the debug
1319 * fault happened on the sysenter path.
1324 CFI_ADJUST_CFA_OFFSET 4
1326 cmpw $__ESPFIX_SS, %ax
1328 CFI_ADJUST_CFA_OFFSET -4
1330 cmpl $ia32_sysenter_target,(%esp)
1333 CFI_ADJUST_CFA_OFFSET 4
1335 /* Do not access memory above the end of our stack page,
1336 * it might not exist.
1338 andl $(THREAD_SIZE-1),%eax
1339 cmpl $(THREAD_SIZE-20),%eax
1341 CFI_ADJUST_CFA_OFFSET -4
1342 jae nmi_stack_correct
1343 cmpl $ia32_sysenter_target,12(%esp)
1344 je nmi_debug_stack_check
1346 /* We have a RING0_INT_FRAME here */
1348 CFI_ADJUST_CFA_OFFSET 4
1350 xorl %edx,%edx # zero error code
1351 movl %esp,%eax # pt_regs pointer
1353 jmp restore_all_notrace
1358 FIX_STACK 12, nmi_stack_correct, 1
1359 jmp nmi_stack_correct
1361 nmi_debug_stack_check:
1362 /* We have a RING0_INT_FRAME here */
1363 cmpw $__KERNEL_CS,16(%esp)
1364 jne nmi_stack_correct
1366 jb nmi_stack_correct
1367 cmpl $debug_esp_fix_insn,(%esp)
1368 ja nmi_stack_correct
1369 FIX_STACK 24, nmi_stack_correct, 1
1370 jmp nmi_stack_correct
1373 /* We have a RING0_INT_FRAME here.
1375 * create the pointer to lss back
1378 CFI_ADJUST_CFA_OFFSET 4
1380 CFI_ADJUST_CFA_OFFSET 4
1382 /* copy the iret frame of 12 bytes */
1385 CFI_ADJUST_CFA_OFFSET 4
1388 CFI_ADJUST_CFA_OFFSET 4
1390 FIXUP_ESPFIX_STACK # %eax == %esp
1391 xorl %edx,%edx # zero error code
1394 lss 12+4(%esp), %esp # back to espfix stack
1395 CFI_ADJUST_CFA_OFFSET -24
1402 pushl $-1 # mark this as an int
1403 CFI_ADJUST_CFA_OFFSET 4
1406 xorl %edx,%edx # zero error code
1407 movl %esp,%eax # pt_regs pointer
1409 jmp ret_from_exception
1413 ENTRY(general_protection)
1415 pushl $do_general_protection
1416 CFI_ADJUST_CFA_OFFSET 4
1419 END(general_protection)
1422 * End of kprobes section