2 * linux/arch/i386/entry.S
4 * Copyright (C) 1991, 1992 Linus Torvalds
8 * entry.S contains the system-call and fault low-level handling routines.
9 * This also contains the timer-interrupt handler, as well as all interrupts
10 * and faults that can result in a task-switch.
12 * NOTE: This code handles signal-recognition, which happens every time
13 * after a timer-interrupt and after each system call.
15 * I changed all the .align's to 4 (16 byte alignment), as that's faster
18 * Stack layout in 'syscall_exit':
19 * ptrace needs to have all regs on the stack.
20 * if the order here is changed, it needs to be
21 * updated in fork.c:copy_process, signal.c:do_signal,
22 * ptrace.c and ptrace.h
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>
52 #include <asm/percpu.h>
53 #include <asm/dwarf2.h>
54 #include "irq_vectors.h"
57 * We use macros for low-level operations which need to be overridden
58 * for paravirtualization. The following will never clobber any registers:
59 * INTERRUPT_RETURN (aka. "iret")
60 * GET_CR0_INTO_EAX (aka. "movl %cr0, %eax")
61 * ENABLE_INTERRUPTS_SYSCALL_RET (aka "sti; sysexit").
63 * For DISABLE_INTERRUPTS/ENABLE_INTERRUPTS (aka "cli"/"sti"), you must
64 * specify what registers can be overwritten (CLBR_NONE, CLBR_EAX/EDX/ECX/ANY).
65 * Allowing a register to be clobbered can shrink the paravirt replacement
66 * enough to patch inline, increasing performance.
69 #define nr_syscalls ((syscall_table_size)/4)
79 #define preempt_stop(clobbers) DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF
81 #define preempt_stop(clobbers)
82 #define resume_kernel restore_nocheck
85 .macro TRACE_IRQS_IRET
86 #ifdef CONFIG_TRACE_IRQFLAGS
87 testl $IF_MASK,PT_EFLAGS(%esp) # interrupts off?
95 #define resume_userspace_sig check_userspace
97 #define resume_userspace_sig resume_userspace
103 CFI_ADJUST_CFA_OFFSET 4;\
104 /*CFI_REL_OFFSET fs, 0;*/\
106 CFI_ADJUST_CFA_OFFSET 4;\
107 /*CFI_REL_OFFSET es, 0;*/\
109 CFI_ADJUST_CFA_OFFSET 4;\
110 /*CFI_REL_OFFSET ds, 0;*/\
112 CFI_ADJUST_CFA_OFFSET 4;\
113 CFI_REL_OFFSET eax, 0;\
115 CFI_ADJUST_CFA_OFFSET 4;\
116 CFI_REL_OFFSET ebp, 0;\
118 CFI_ADJUST_CFA_OFFSET 4;\
119 CFI_REL_OFFSET edi, 0;\
121 CFI_ADJUST_CFA_OFFSET 4;\
122 CFI_REL_OFFSET esi, 0;\
124 CFI_ADJUST_CFA_OFFSET 4;\
125 CFI_REL_OFFSET edx, 0;\
127 CFI_ADJUST_CFA_OFFSET 4;\
128 CFI_REL_OFFSET ecx, 0;\
130 CFI_ADJUST_CFA_OFFSET 4;\
131 CFI_REL_OFFSET ebx, 0;\
132 movl $(__USER_DS), %edx; \
135 movl $(__KERNEL_PERCPU), %edx; \
138 #define RESTORE_INT_REGS \
140 CFI_ADJUST_CFA_OFFSET -4;\
143 CFI_ADJUST_CFA_OFFSET -4;\
146 CFI_ADJUST_CFA_OFFSET -4;\
149 CFI_ADJUST_CFA_OFFSET -4;\
152 CFI_ADJUST_CFA_OFFSET -4;\
155 CFI_ADJUST_CFA_OFFSET -4;\
158 CFI_ADJUST_CFA_OFFSET -4;\
161 #define RESTORE_REGS \
164 CFI_ADJUST_CFA_OFFSET -4;\
167 CFI_ADJUST_CFA_OFFSET -4;\
170 CFI_ADJUST_CFA_OFFSET -4;\
172 .pushsection .fixup,"ax"; \
179 .section __ex_table,"a";\
186 #define RING0_INT_FRAME \
187 CFI_STARTPROC simple;\
189 CFI_DEF_CFA esp, 3*4;\
190 /*CFI_OFFSET cs, -2*4;*/\
193 #define RING0_EC_FRAME \
194 CFI_STARTPROC simple;\
196 CFI_DEF_CFA esp, 4*4;\
197 /*CFI_OFFSET cs, -2*4;*/\
200 #define RING0_PTREGS_FRAME \
201 CFI_STARTPROC simple;\
203 CFI_DEF_CFA esp, PT_OLDESP-PT_EBX;\
204 /*CFI_OFFSET cs, PT_CS-PT_OLDESP;*/\
205 CFI_OFFSET eip, PT_EIP-PT_OLDESP;\
206 /*CFI_OFFSET es, PT_ES-PT_OLDESP;*/\
207 /*CFI_OFFSET ds, PT_DS-PT_OLDESP;*/\
208 CFI_OFFSET eax, PT_EAX-PT_OLDESP;\
209 CFI_OFFSET ebp, PT_EBP-PT_OLDESP;\
210 CFI_OFFSET edi, PT_EDI-PT_OLDESP;\
211 CFI_OFFSET esi, PT_ESI-PT_OLDESP;\
212 CFI_OFFSET edx, PT_EDX-PT_OLDESP;\
213 CFI_OFFSET ecx, PT_ECX-PT_OLDESP;\
214 CFI_OFFSET ebx, PT_EBX-PT_OLDESP
219 CFI_ADJUST_CFA_OFFSET 4
221 GET_THREAD_INFO(%ebp)
223 CFI_ADJUST_CFA_OFFSET -4
224 pushl $0x0202 # Reset kernel eflags
225 CFI_ADJUST_CFA_OFFSET 4
227 CFI_ADJUST_CFA_OFFSET -4
233 * Return to user mode is not as complex as all this looks,
234 * but we want the default path for a system call return to
235 * go as quickly as possible which is why some of this is
236 * less clear than it otherwise should be.
239 # userspace resumption stub bypassing syscall exit tracing
243 preempt_stop(CLBR_ANY)
245 GET_THREAD_INFO(%ebp)
247 movl PT_EFLAGS(%esp), %eax # mix EFLAGS and CS
248 movb PT_CS(%esp), %al
249 andl $(VM_MASK | SEGMENT_RPL_MASK), %eax
251 jb resume_kernel # not returning to v8086 or userspace
253 ENTRY(resume_userspace)
255 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
256 # setting need_resched or sigpending
257 # between sampling and the iret
258 movl TI_flags(%ebp), %ecx
259 andl $_TIF_WORK_MASK, %ecx # is there any work to be done on
260 # int/exception return?
263 END(ret_from_exception)
265 #ifdef CONFIG_PREEMPT
267 DISABLE_INTERRUPTS(CLBR_ANY)
268 cmpl $0,TI_preempt_count(%ebp) # non-zero preempt_count ?
271 movl TI_flags(%ebp), %ecx # need_resched set ?
272 testb $_TIF_NEED_RESCHED, %cl
274 testl $IF_MASK,PT_EFLAGS(%esp) # interrupts off (exception path) ?
276 call preempt_schedule_irq
282 /* SYSENTER_RETURN points to after the "sysenter" instruction in
283 the vsyscall page. See vsyscall-sysentry.S, which defines the symbol. */
285 # sysenter call handler stub
286 ENTRY(ia32_sysenter_target)
290 CFI_REGISTER esp, ebp
291 movl TSS_sysenter_sp0(%esp),%esp
294 * Interrupts are disabled here, but we can't trace it until
295 * enough kernel state to call TRACE_IRQS_OFF can be called - but
296 * we immediately enable interrupts at that point anyway.
299 CFI_ADJUST_CFA_OFFSET 4
300 /*CFI_REL_OFFSET ss, 0*/
302 CFI_ADJUST_CFA_OFFSET 4
303 CFI_REL_OFFSET esp, 0
305 orl $X86_EFLAGS_IF, (%esp)
306 CFI_ADJUST_CFA_OFFSET 4
308 CFI_ADJUST_CFA_OFFSET 4
309 /*CFI_REL_OFFSET cs, 0*/
311 * Push current_thread_info()->sysenter_return to the stack.
312 * A tiny bit of offset fixup is necessary - 4*4 means the 4 words
313 * pushed above; +8 corresponds to copy_thread's esp0 setting.
315 pushl (TI_sysenter_return-THREAD_SIZE+8+4*4)(%esp)
316 CFI_ADJUST_CFA_OFFSET 4
317 CFI_REL_OFFSET eip, 0
320 CFI_ADJUST_CFA_OFFSET 4
322 ENABLE_INTERRUPTS(CLBR_NONE)
325 * Load the potential sixth argument from user stack.
326 * Careful about security.
328 cmpl $__PAGE_OFFSET-3,%ebp
331 movl %ebp,PT_EBP(%esp)
332 .section __ex_table,"a"
334 .long 1b,syscall_fault
337 GET_THREAD_INFO(%ebp)
339 /* Note, _TIF_SECCOMP is bit number 8, and so it needs testw and not testb */
340 testw $(_TIF_SYSCALL_EMU|_TIF_SYSCALL_TRACE|_TIF_SECCOMP|_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
341 jnz syscall_trace_entry
342 cmpl $(nr_syscalls), %eax
344 call *sys_call_table(,%eax,4)
345 movl %eax,PT_EAX(%esp)
347 DISABLE_INTERRUPTS(CLBR_ANY)
349 movl TI_flags(%ebp), %ecx
350 testw $_TIF_ALLWORK_MASK, %cx
351 jne syscall_exit_work
352 /* if something modifies registers it must also disable sysexit */
353 movl PT_EIP(%esp), %edx
354 movl PT_OLDESP(%esp), %ecx
357 1: mov PT_FS(%esp), %fs
358 ENABLE_INTERRUPTS_SYSCALL_RET
360 .pushsection .fixup,"ax"
361 2: movl $0,PT_FS(%esp)
363 .section __ex_table,"a"
367 ENDPROC(ia32_sysenter_target)
369 # system call handler stub
371 RING0_INT_FRAME # can't unwind into user space anyway
372 pushl %eax # save orig_eax
373 CFI_ADJUST_CFA_OFFSET 4
375 GET_THREAD_INFO(%ebp)
376 # system call tracing in operation / emulation
377 /* Note, _TIF_SECCOMP is bit number 8, and so it needs testw and not testb */
378 testw $(_TIF_SYSCALL_EMU|_TIF_SYSCALL_TRACE|_TIF_SECCOMP|_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
379 jnz syscall_trace_entry
380 cmpl $(nr_syscalls), %eax
383 call *sys_call_table(,%eax,4)
384 movl %eax,PT_EAX(%esp) # store the return value
387 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
388 # setting need_resched or sigpending
389 # between sampling and the iret
391 testl $TF_MASK,PT_EFLAGS(%esp) # If tracing set singlestep flag on exit
393 orl $_TIF_SINGLESTEP,TI_flags(%ebp)
395 movl TI_flags(%ebp), %ecx
396 testw $_TIF_ALLWORK_MASK, %cx # current->work
397 jne syscall_exit_work
400 movl PT_EFLAGS(%esp), %eax # mix EFLAGS, SS and CS
401 # Warning: PT_OLDSS(%esp) contains the wrong/random values if we
402 # are returning to the kernel.
403 # See comments in process.c:copy_thread() for details.
404 movb PT_OLDSS(%esp), %ah
405 movb PT_CS(%esp), %al
406 andl $(VM_MASK | (SEGMENT_TI_MASK << 8) | SEGMENT_RPL_MASK), %eax
407 cmpl $((SEGMENT_LDT << 8) | USER_RPL), %eax
409 je ldt_ss # returning to user-space with LDT SS
412 restore_nocheck_notrace:
414 addl $4, %esp # skip orig_eax/error_code
415 CFI_ADJUST_CFA_OFFSET -4
420 pushl $0 # no error code
424 .section __ex_table,"a"
426 .long irq_return,iret_exc
431 larl PT_OLDSS(%esp), %eax
433 testl $0x00400000, %eax # returning to 32bit stack?
434 jnz restore_nocheck # allright, normal return
436 #ifdef CONFIG_PARAVIRT
438 * The kernel can't run on a non-flat stack if paravirt mode
439 * is active. Rather than try to fixup the high bits of
440 * ESP, bypass this code entirely. This may break DOSemu
441 * and/or Wine support in a paravirt VM, although the option
442 * is still available to implement the setting of the high
443 * 16-bits in the INTERRUPT_RETURN paravirt-op.
445 cmpl $0, pv_info+PARAVIRT_enabled
449 /* If returning to userspace with 16bit stack,
450 * try to fix the higher word of ESP, as the CPU
452 * This is an "official" bug of all the x86-compatible
453 * CPUs, which we can try to work around to make
454 * dosemu and wine happy. */
455 movl PT_OLDESP(%esp), %eax
457 call patch_espfix_desc
459 CFI_ADJUST_CFA_OFFSET 4
461 CFI_ADJUST_CFA_OFFSET 4
462 DISABLE_INTERRUPTS(CLBR_EAX)
465 CFI_ADJUST_CFA_OFFSET -8
470 # perform work that needs to be done immediately before resumption
472 RING0_PTREGS_FRAME # can't unwind into user space anyway
474 testb $_TIF_NEED_RESCHED, %cl
479 DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt
480 # setting need_resched or sigpending
481 # between sampling and the iret
483 movl TI_flags(%ebp), %ecx
484 andl $_TIF_WORK_MASK, %ecx # is there any work to be done other
485 # than syscall tracing?
487 testb $_TIF_NEED_RESCHED, %cl
490 work_notifysig: # deal with pending signals and
491 # notify-resume requests
493 testl $VM_MASK, PT_EFLAGS(%esp)
495 jne work_notifysig_v86 # returning to kernel-space or
498 call do_notify_resume
499 jmp resume_userspace_sig
503 pushl %ecx # save ti_flags for do_notify_resume
504 CFI_ADJUST_CFA_OFFSET 4
505 call save_v86_state # %eax contains pt_regs pointer
507 CFI_ADJUST_CFA_OFFSET -4
513 call do_notify_resume
514 jmp resume_userspace_sig
517 # perform syscall exit tracing
520 movl $-ENOSYS,PT_EAX(%esp)
523 call do_syscall_trace
525 jne resume_userspace # ret != 0 -> running under PTRACE_SYSEMU,
526 # so must skip actual syscall
527 movl PT_ORIG_EAX(%esp), %eax
528 cmpl $(nr_syscalls), %eax
531 END(syscall_trace_entry)
533 # perform syscall exit tracing
536 testb $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP), %cl
539 ENABLE_INTERRUPTS(CLBR_ANY) # could let do_syscall_trace() call
543 call do_syscall_trace
545 END(syscall_exit_work)
548 RING0_INT_FRAME # can't unwind into user space anyway
550 GET_THREAD_INFO(%ebp)
551 movl $-EFAULT,PT_EAX(%esp)
556 movl $-ENOSYS,PT_EAX(%esp)
561 #define FIXUP_ESPFIX_STACK \
562 /* since we are on a wrong stack, we cant make it a C code :( */ \
563 PER_CPU(gdt_page, %ebx); \
564 GET_DESC_BASE(GDT_ENTRY_ESPFIX_SS, %ebx, %eax, %ax, %al, %ah); \
566 pushl $__KERNEL_DS; \
567 CFI_ADJUST_CFA_OFFSET 4; \
569 CFI_ADJUST_CFA_OFFSET 4; \
571 CFI_ADJUST_CFA_OFFSET -8;
572 #define UNWIND_ESPFIX_STACK \
574 /* see if on espfix stack */ \
575 cmpw $__ESPFIX_SS, %ax; \
577 movl $__KERNEL_DS, %eax; \
580 /* switch to normal stack */ \
581 FIXUP_ESPFIX_STACK; \
585 * Build the entry stubs and pointer table with
586 * some assembler magic.
592 ENTRY(irq_entries_start)
598 CFI_ADJUST_CFA_OFFSET -4
601 CFI_ADJUST_CFA_OFFSET 4
608 END(irq_entries_start)
615 * the CPU automatically disables interrupts when executing an IRQ vector,
616 * so IRQ-flags tracing has to follow that:
625 ENDPROC(common_interrupt)
628 #define BUILD_INTERRUPT(name, nr) \
632 CFI_ADJUST_CFA_OFFSET 4; \
641 /* The include is where all of the SMP etc. interrupts come from */
642 #include "entry_arch.h"
644 KPROBE_ENTRY(page_fault)
647 CFI_ADJUST_CFA_OFFSET 4
650 /* the function address is in %fs's slot on the stack */
652 CFI_ADJUST_CFA_OFFSET 4
653 /*CFI_REL_OFFSET es, 0*/
655 CFI_ADJUST_CFA_OFFSET 4
656 /*CFI_REL_OFFSET ds, 0*/
658 CFI_ADJUST_CFA_OFFSET 4
659 CFI_REL_OFFSET eax, 0
661 CFI_ADJUST_CFA_OFFSET 4
662 CFI_REL_OFFSET ebp, 0
664 CFI_ADJUST_CFA_OFFSET 4
665 CFI_REL_OFFSET edi, 0
667 CFI_ADJUST_CFA_OFFSET 4
668 CFI_REL_OFFSET esi, 0
670 CFI_ADJUST_CFA_OFFSET 4
671 CFI_REL_OFFSET edx, 0
673 CFI_ADJUST_CFA_OFFSET 4
674 CFI_REL_OFFSET ecx, 0
676 CFI_ADJUST_CFA_OFFSET 4
677 CFI_REL_OFFSET ebx, 0
680 CFI_ADJUST_CFA_OFFSET 4
681 /*CFI_REL_OFFSET fs, 0*/
682 movl $(__KERNEL_PERCPU), %ecx
686 CFI_ADJUST_CFA_OFFSET -4
687 /*CFI_REGISTER es, ecx*/
688 movl PT_FS(%esp), %edi # get the function address
689 movl PT_ORIG_EAX(%esp), %edx # get the error code
690 movl $-1, PT_ORIG_EAX(%esp) # no syscall to restart
691 mov %ecx, PT_FS(%esp)
692 /*CFI_REL_OFFSET fs, ES*/
693 movl $(__USER_DS), %ecx
696 movl %esp,%eax # pt_regs pointer
698 jmp ret_from_exception
700 KPROBE_END(page_fault)
702 ENTRY(coprocessor_error)
705 CFI_ADJUST_CFA_OFFSET 4
706 pushl $do_coprocessor_error
707 CFI_ADJUST_CFA_OFFSET 4
710 END(coprocessor_error)
712 ENTRY(simd_coprocessor_error)
715 CFI_ADJUST_CFA_OFFSET 4
716 pushl $do_simd_coprocessor_error
717 CFI_ADJUST_CFA_OFFSET 4
720 END(simd_coprocessor_error)
722 ENTRY(device_not_available)
724 pushl $-1 # mark this as an int
725 CFI_ADJUST_CFA_OFFSET 4
728 testl $0x4, %eax # EM (math emulation bit)
729 jne device_not_available_emulate
730 preempt_stop(CLBR_ANY)
731 call math_state_restore
732 jmp ret_from_exception
733 device_not_available_emulate:
734 pushl $0 # temporary storage for ORIG_EIP
735 CFI_ADJUST_CFA_OFFSET 4
738 CFI_ADJUST_CFA_OFFSET -4
739 jmp ret_from_exception
741 END(device_not_available)
744 * Debug traps and NMI can happen at the one SYSENTER instruction
745 * that sets up the real kernel stack. Check here, since we can't
746 * allow the wrong stack to be used.
748 * "TSS_sysenter_sp0+12" is because the NMI/debug handler will have
749 * already pushed 3 words if it hits on the sysenter instruction:
750 * eflags, cs and eip.
752 * We just load the right stack, and push the three (known) values
753 * by hand onto the new stack - while updating the return eip past
754 * the instruction that would have done it for sysenter.
756 #define FIX_STACK(offset, ok, label) \
757 cmpw $__KERNEL_CS,4(%esp); \
760 movl TSS_sysenter_sp0+offset(%esp),%esp; \
761 CFI_DEF_CFA esp, 0; \
764 CFI_ADJUST_CFA_OFFSET 4; \
765 pushl $__KERNEL_CS; \
766 CFI_ADJUST_CFA_OFFSET 4; \
767 pushl $sysenter_past_esp; \
768 CFI_ADJUST_CFA_OFFSET 4; \
769 CFI_REL_OFFSET eip, 0
773 cmpl $ia32_sysenter_target,(%esp)
774 jne debug_stack_correct
775 FIX_STACK(12, debug_stack_correct, debug_esp_fix_insn)
777 pushl $-1 # mark this as an int
778 CFI_ADJUST_CFA_OFFSET 4
780 xorl %edx,%edx # error code 0
781 movl %esp,%eax # pt_regs pointer
783 jmp ret_from_exception
788 * NMI is doubly nasty. It can happen _while_ we're handling
789 * a debug fault, and the debug fault hasn't yet been able to
790 * clear up the stack. So we first check whether we got an
791 * NMI on the sysenter entry path, but after that we need to
792 * check whether we got an NMI on the debug path where the debug
793 * fault happened on the sysenter path.
798 CFI_ADJUST_CFA_OFFSET 4
800 cmpw $__ESPFIX_SS, %ax
802 CFI_ADJUST_CFA_OFFSET -4
804 cmpl $ia32_sysenter_target,(%esp)
807 CFI_ADJUST_CFA_OFFSET 4
809 /* Do not access memory above the end of our stack page,
810 * it might not exist.
812 andl $(THREAD_SIZE-1),%eax
813 cmpl $(THREAD_SIZE-20),%eax
815 CFI_ADJUST_CFA_OFFSET -4
816 jae nmi_stack_correct
817 cmpl $ia32_sysenter_target,12(%esp)
818 je nmi_debug_stack_check
820 /* We have a RING0_INT_FRAME here */
822 CFI_ADJUST_CFA_OFFSET 4
824 xorl %edx,%edx # zero error code
825 movl %esp,%eax # pt_regs pointer
827 jmp restore_nocheck_notrace
832 FIX_STACK(12,nmi_stack_correct, 1)
833 jmp nmi_stack_correct
835 nmi_debug_stack_check:
836 /* We have a RING0_INT_FRAME here */
837 cmpw $__KERNEL_CS,16(%esp)
838 jne nmi_stack_correct
841 cmpl $debug_esp_fix_insn,(%esp)
843 FIX_STACK(24,nmi_stack_correct, 1)
844 jmp nmi_stack_correct
847 /* We have a RING0_INT_FRAME here.
849 * create the pointer to lss back
852 CFI_ADJUST_CFA_OFFSET 4
854 CFI_ADJUST_CFA_OFFSET 4
856 /* copy the iret frame of 12 bytes */
859 CFI_ADJUST_CFA_OFFSET 4
862 CFI_ADJUST_CFA_OFFSET 4
864 FIXUP_ESPFIX_STACK # %eax == %esp
865 xorl %edx,%edx # zero error code
868 lss 12+4(%esp), %esp # back to espfix stack
869 CFI_ADJUST_CFA_OFFSET -24
874 #ifdef CONFIG_PARAVIRT
877 .section __ex_table,"a"
879 .long native_iret, iret_exc
883 ENTRY(native_irq_enable_syscall_ret)
886 END(native_irq_enable_syscall_ret)
891 pushl $-1 # mark this as an int
892 CFI_ADJUST_CFA_OFFSET 4
894 xorl %edx,%edx # zero error code
895 movl %esp,%eax # pt_regs pointer
897 jmp ret_from_exception
904 CFI_ADJUST_CFA_OFFSET 4
906 CFI_ADJUST_CFA_OFFSET 4
914 CFI_ADJUST_CFA_OFFSET 4
916 CFI_ADJUST_CFA_OFFSET 4
924 CFI_ADJUST_CFA_OFFSET 4
926 CFI_ADJUST_CFA_OFFSET 4
931 ENTRY(coprocessor_segment_overrun)
934 CFI_ADJUST_CFA_OFFSET 4
935 pushl $do_coprocessor_segment_overrun
936 CFI_ADJUST_CFA_OFFSET 4
939 END(coprocessor_segment_overrun)
943 pushl $do_invalid_TSS
944 CFI_ADJUST_CFA_OFFSET 4
949 ENTRY(segment_not_present)
951 pushl $do_segment_not_present
952 CFI_ADJUST_CFA_OFFSET 4
955 END(segment_not_present)
959 pushl $do_stack_segment
960 CFI_ADJUST_CFA_OFFSET 4
965 KPROBE_ENTRY(general_protection)
967 pushl $do_general_protection
968 CFI_ADJUST_CFA_OFFSET 4
971 KPROBE_END(general_protection)
973 ENTRY(alignment_check)
975 pushl $do_alignment_check
976 CFI_ADJUST_CFA_OFFSET 4
983 pushl $0 # no error code
984 CFI_ADJUST_CFA_OFFSET 4
985 pushl $do_divide_error
986 CFI_ADJUST_CFA_OFFSET 4
991 #ifdef CONFIG_X86_MCE
995 CFI_ADJUST_CFA_OFFSET 4
996 pushl machine_check_vector
997 CFI_ADJUST_CFA_OFFSET 4
1003 ENTRY(spurious_interrupt_bug)
1006 CFI_ADJUST_CFA_OFFSET 4
1007 pushl $do_spurious_interrupt_bug
1008 CFI_ADJUST_CFA_OFFSET 4
1011 END(spurious_interrupt_bug)
1013 ENTRY(kernel_thread_helper)
1014 pushl $0 # fake return address for unwinder
1018 CFI_ADJUST_CFA_OFFSET 4
1021 CFI_ADJUST_CFA_OFFSET 4
1024 ENDPROC(kernel_thread_helper)
1027 ENTRY(xen_hypervisor_callback)
1030 CFI_ADJUST_CFA_OFFSET 4
1034 /* Check to see if we got the event in the critical
1035 region in xen_iret_direct, after we've reenabled
1036 events and checked for pending events. This simulates
1037 iret instruction's behaviour where it delivers a
1038 pending interrupt when enabling interrupts. */
1039 movl PT_EIP(%esp),%eax
1040 cmpl $xen_iret_start_crit,%eax
1042 cmpl $xen_iret_end_crit,%eax
1045 call xen_iret_crit_fixup
1048 call xen_evtchn_do_upcall
1051 ENDPROC(xen_hypervisor_callback)
1053 # Hypervisor uses this for application faults while it executes.
1054 # We get here for two reasons:
1055 # 1. Fault while reloading DS, ES, FS or GS
1056 # 2. Fault while executing IRET
1057 # Category 1 we fix up by reattempting the load, and zeroing the segment
1058 # register if the load fails.
1059 # Category 2 we fix up by jumping to do_iret_error. We cannot use the
1060 # normal Linux return path in this case because if we use the IRET hypercall
1061 # to pop the stack frame we end up in an infinite loop of failsafe callbacks.
1062 # We distinguish between categories by maintaining a status value in EAX.
1063 ENTRY(xen_failsafe_callback)
1066 CFI_ADJUST_CFA_OFFSET 4
1074 CFI_ADJUST_CFA_OFFSET -4
1076 CFI_ADJUST_CFA_OFFSET -16
1079 jmp iret_exc # EAX != 0 => Category 2 (Bad IRET)
1080 5: pushl $0 # EAX == 0 => Category 1 (Bad segment)
1081 CFI_ADJUST_CFA_OFFSET 4
1083 jmp ret_from_exception
1086 .section .fixup,"ax"
1100 .section __ex_table,"a"
1107 ENDPROC(xen_failsafe_callback)
1109 #endif /* CONFIG_XEN */
1111 .section .rodata,"a"
1112 #include "syscall_table_32.S"
1114 syscall_table_size=(.-sys_call_table)