2 * linux/arch/x86_64/entry.S
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 * Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
6 * Copyright (C) 2000 Pavel Machek <pavel@suse.cz>
12 * entry.S contains the system-call and fault low-level handling routines.
14 * NOTE: This code handles signal-recognition, which happens every time
15 * after an interrupt and after each system call.
17 * Normal syscalls and interrupts don't save a full stack frame, this is
18 * only done for syscall tracing, signals or fork/exec et.al.
20 * A note on terminology:
21 * - top of stack: Architecture defined interrupt frame from SS to RIP
22 * at the top of the kernel process stack.
23 * - partial stack frame: partially saved registers upto R11.
24 * - full stack frame: Like partial stack frame, but all register saved.
27 * - CFI macros are used to generate dwarf2 unwind information for better
28 * backtraces. They don't change any code.
29 * - SAVE_ALL/RESTORE_ALL - Save/restore all registers
30 * - SAVE_ARGS/RESTORE_ARGS - Save/restore registers that C functions modify.
31 * There are unfortunately lots of special cases where some registers
32 * not touched. The macro is a big mess that should be cleaned up.
33 * - SAVE_REST/RESTORE_REST - Handle the registers not saved by SAVE_ARGS.
34 * Gives a full stack frame.
35 * - ENTRY/END Define functions in the symbol table.
36 * - FIXUP_TOP_OF_STACK/RESTORE_TOP_OF_STACK - Fix up the hardware stack
37 * frame that is otherwise undefined after a SYSCALL
38 * - TRACE_IRQ_* - Trace hard interrupt state for lock debugging.
39 * - errorentry/paranoidentry/zeroentry - Define exception entry points.
42 #include <linux/linkage.h>
43 #include <asm/segment.h>
44 #include <asm/cache.h>
45 #include <asm/errno.h>
46 #include <asm/dwarf2.h>
47 #include <asm/calling.h>
48 #include <asm/asm-offsets.h>
50 #include <asm/unistd.h>
51 #include <asm/thread_info.h>
52 #include <asm/hw_irq.h>
54 #include <asm/irqflags.h>
58 #ifndef CONFIG_PREEMPT
59 #define retint_kernel retint_restore_args
63 .macro TRACE_IRQS_IRETQ offset=ARGOFFSET
64 #ifdef CONFIG_TRACE_IRQFLAGS
65 bt $9,EFLAGS-\offset(%rsp) /* interrupts off? */
73 * C code is not supposed to know about undefined top of stack. Every time
74 * a C function with an pt_regs argument is called from the SYSCALL based
75 * fast path FIXUP_TOP_OF_STACK is needed.
76 * RESTORE_TOP_OF_STACK syncs the syscall state after any possible ptregs
80 /* %rsp:at FRAMEEND */
81 .macro FIXUP_TOP_OF_STACK tmp
82 movq %gs:pda_oldrsp,\tmp
84 movq $__USER_DS,SS(%rsp)
85 movq $__USER_CS,CS(%rsp)
87 movq R11(%rsp),\tmp /* get eflags */
88 movq \tmp,EFLAGS(%rsp)
91 .macro RESTORE_TOP_OF_STACK tmp,offset=0
92 movq RSP-\offset(%rsp),\tmp
93 movq \tmp,%gs:pda_oldrsp
94 movq EFLAGS-\offset(%rsp),\tmp
95 movq \tmp,R11-\offset(%rsp)
98 .macro FAKE_STACK_FRAME child_rip
99 /* push in order ss, rsp, eflags, cs, rip */
102 CFI_ADJUST_CFA_OFFSET 8
103 /*CFI_REL_OFFSET ss,0*/
105 CFI_ADJUST_CFA_OFFSET 8
107 pushq $(1<<9) /* eflags - interrupts on */
108 CFI_ADJUST_CFA_OFFSET 8
109 /*CFI_REL_OFFSET rflags,0*/
110 pushq $__KERNEL_CS /* cs */
111 CFI_ADJUST_CFA_OFFSET 8
112 /*CFI_REL_OFFSET cs,0*/
113 pushq \child_rip /* rip */
114 CFI_ADJUST_CFA_OFFSET 8
116 pushq %rax /* orig rax */
117 CFI_ADJUST_CFA_OFFSET 8
120 .macro UNFAKE_STACK_FRAME
122 CFI_ADJUST_CFA_OFFSET -(6*8)
125 .macro CFI_DEFAULT_STACK start=1
130 CFI_DEF_CFA_OFFSET SS+8
132 CFI_REL_OFFSET r15,R15
133 CFI_REL_OFFSET r14,R14
134 CFI_REL_OFFSET r13,R13
135 CFI_REL_OFFSET r12,R12
136 CFI_REL_OFFSET rbp,RBP
137 CFI_REL_OFFSET rbx,RBX
138 CFI_REL_OFFSET r11,R11
139 CFI_REL_OFFSET r10,R10
142 CFI_REL_OFFSET rax,RAX
143 CFI_REL_OFFSET rcx,RCX
144 CFI_REL_OFFSET rdx,RDX
145 CFI_REL_OFFSET rsi,RSI
146 CFI_REL_OFFSET rdi,RDI
147 CFI_REL_OFFSET rip,RIP
148 /*CFI_REL_OFFSET cs,CS*/
149 /*CFI_REL_OFFSET rflags,EFLAGS*/
150 CFI_REL_OFFSET rsp,RSP
151 /*CFI_REL_OFFSET ss,SS*/
154 * A newly forked process directly context switches into this.
160 GET_THREAD_INFO(%rcx)
161 testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT),threadinfo_flags(%rcx)
165 testl $3,CS-ARGOFFSET(%rsp) # from kernel_thread?
166 je int_ret_from_sys_call
167 testl $_TIF_IA32,threadinfo_flags(%rcx)
168 jnz int_ret_from_sys_call
169 RESTORE_TOP_OF_STACK %rdi,ARGOFFSET
170 jmp ret_from_sys_call
173 call syscall_trace_leave
174 GET_THREAD_INFO(%rcx)
180 * System call entry. Upto 6 arguments in registers are supported.
182 * SYSCALL does not save anything on the stack and does not change the
188 * rax system call number
190 * rcx return address for syscall/sysret, C arg3
193 * r10 arg3 (--> moved to rcx for C)
196 * r11 eflags for syscall/sysret, temporary for C
197 * r12-r15,rbp,rbx saved by C code, not touched.
199 * Interrupts are off on entry.
200 * Only called from user space.
202 * XXX if we had a free scratch register we could save the RSP into the stack frame
203 * and report it properly in ps. Unfortunately we haven't.
205 * When user can change the frames always force IRET. That is because
206 * it deals with uncanonical addresses better. SYSRET has trouble
207 * with them due to bugs in both AMD and Intel CPUs.
212 CFI_DEF_CFA rsp,PDA_STACKOFFSET
214 /*CFI_REGISTER rflags,r11*/
216 movq %rsp,%gs:pda_oldrsp
217 movq %gs:pda_kernelstack,%rsp
219 * No need to follow this irqs off/on section - it's straight
224 movq %rax,ORIG_RAX-ARGOFFSET(%rsp)
225 movq %rcx,RIP-ARGOFFSET(%rsp)
226 CFI_REL_OFFSET rip,RIP-ARGOFFSET
227 GET_THREAD_INFO(%rcx)
228 testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP),threadinfo_flags(%rcx)
231 cmpq $__NR_syscall_max,%rax
234 call *sys_call_table(,%rax,8) # XXX: rip relative
235 movq %rax,RAX-ARGOFFSET(%rsp)
237 * Syscall return path ending with SYSRET (fast path)
238 * Has incomplete stack frame and undefined top of stack.
240 .globl ret_from_sys_call
242 movl $_TIF_ALLWORK_MASK,%edi
245 GET_THREAD_INFO(%rcx)
248 movl threadinfo_flags(%rcx),%edx
253 * sysretq will re-enable interrupts:
256 movq RIP-ARGOFFSET(%rsp),%rcx
258 RESTORE_ARGS 0,-ARG_SKIP,1
259 /*CFI_REGISTER rflags,r11*/
260 movq %gs:pda_oldrsp,%rsp
264 /* Handle reschedules */
265 /* edx: work, edi: workmask */
268 bt $TIF_NEED_RESCHED,%edx
273 CFI_ADJUST_CFA_OFFSET 8
276 CFI_ADJUST_CFA_OFFSET -8
279 /* Handle a signal */
283 testl $(_TIF_SIGPENDING|_TIF_NOTIFY_RESUME|_TIF_SINGLESTEP),%edx
286 /* Really a signal */
287 /* edx: work flags (arg3) */
288 leaq do_notify_resume(%rip),%rax
289 leaq -ARGOFFSET(%rsp),%rdi # &pt_regs -> arg1
290 xorl %esi,%esi # oldset -> arg2
291 call ptregscall_common
292 1: movl $_TIF_NEED_RESCHED,%edi
293 /* Use IRET because user could have changed frame. This
294 works because ptregscall_common has called FIXUP_TOP_OF_STACK. */
300 movq $-ENOSYS,RAX-ARGOFFSET(%rsp)
301 jmp ret_from_sys_call
303 /* Do syscall tracing */
307 movq $-ENOSYS,RAX(%rsp)
308 FIXUP_TOP_OF_STACK %rdi
310 call syscall_trace_enter
311 LOAD_ARGS ARGOFFSET /* reload args from stack in case ptrace changed it */
313 cmpq $__NR_syscall_max,%rax
315 movq %r10,%rcx /* fixup for C */
316 call *sys_call_table(,%rax,8)
317 1: movq %rax,RAX-ARGOFFSET(%rsp)
318 /* Use IRET because user could have changed frame */
319 jmp int_ret_from_sys_call
324 * Syscall return path ending with IRET.
325 * Has correct top of stack, but partial stack frame.
327 ENTRY(int_ret_from_sys_call)
329 CFI_DEF_CFA rsp,SS+8-ARGOFFSET
330 /*CFI_REL_OFFSET ss,SS-ARGOFFSET*/
331 CFI_REL_OFFSET rsp,RSP-ARGOFFSET
332 /*CFI_REL_OFFSET rflags,EFLAGS-ARGOFFSET*/
333 /*CFI_REL_OFFSET cs,CS-ARGOFFSET*/
334 CFI_REL_OFFSET rip,RIP-ARGOFFSET
335 CFI_REL_OFFSET rdx,RDX-ARGOFFSET
336 CFI_REL_OFFSET rcx,RCX-ARGOFFSET
337 CFI_REL_OFFSET rax,RAX-ARGOFFSET
338 CFI_REL_OFFSET rdi,RDI-ARGOFFSET
339 CFI_REL_OFFSET rsi,RSI-ARGOFFSET
340 CFI_REL_OFFSET r8,R8-ARGOFFSET
341 CFI_REL_OFFSET r9,R9-ARGOFFSET
342 CFI_REL_OFFSET r10,R10-ARGOFFSET
343 CFI_REL_OFFSET r11,R11-ARGOFFSET
346 testl $3,CS-ARGOFFSET(%rsp)
347 je retint_restore_args
348 movl $_TIF_ALLWORK_MASK,%edi
349 /* edi: mask to check */
351 GET_THREAD_INFO(%rcx)
352 movl threadinfo_flags(%rcx),%edx
355 andl $~TS_COMPAT,threadinfo_status(%rcx)
358 /* Either reschedule or signal or syscall exit tracking needed. */
359 /* First do a reschedule test. */
360 /* edx: work, edi: workmask */
362 bt $TIF_NEED_RESCHED,%edx
367 CFI_ADJUST_CFA_OFFSET 8
370 CFI_ADJUST_CFA_OFFSET -8
375 /* handle signals and tracing -- both require a full stack frame */
380 /* Check for syscall exit trace */
381 testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP),%edx
384 CFI_ADJUST_CFA_OFFSET 8
385 leaq 8(%rsp),%rdi # &ptregs -> arg1
386 call syscall_trace_leave
388 CFI_ADJUST_CFA_OFFSET -8
389 andl $~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP),%edi
395 testl $(_TIF_NOTIFY_RESUME|_TIF_SIGPENDING|_TIF_SINGLESTEP),%edx
397 movq %rsp,%rdi # &ptregs -> arg1
398 xorl %esi,%esi # oldset -> arg2
399 call do_notify_resume
400 1: movl $_TIF_NEED_RESCHED,%edi
407 END(int_ret_from_sys_call)
410 * Certain special system calls that need to save a complete full stack frame.
413 .macro PTREGSCALL label,func,arg
416 leaq \func(%rip),%rax
417 leaq -ARGOFFSET+8(%rsp),\arg /* 8 for return address */
418 jmp ptregscall_common
424 PTREGSCALL stub_clone, sys_clone, %r8
425 PTREGSCALL stub_fork, sys_fork, %rdi
426 PTREGSCALL stub_vfork, sys_vfork, %rdi
427 PTREGSCALL stub_rt_sigsuspend, sys_rt_sigsuspend, %rdx
428 PTREGSCALL stub_sigaltstack, sys_sigaltstack, %rdx
429 PTREGSCALL stub_iopl, sys_iopl, %rsi
431 ENTRY(ptregscall_common)
433 CFI_ADJUST_CFA_OFFSET -8
434 CFI_REGISTER rip, r11
437 CFI_REGISTER rip, r15
438 FIXUP_TOP_OF_STACK %r11
440 RESTORE_TOP_OF_STACK %r11
442 CFI_REGISTER rip, r11
445 CFI_ADJUST_CFA_OFFSET 8
446 CFI_REL_OFFSET rip, 0
449 END(ptregscall_common)
454 CFI_ADJUST_CFA_OFFSET -8
455 CFI_REGISTER rip, r11
457 FIXUP_TOP_OF_STACK %r11
459 RESTORE_TOP_OF_STACK %r11
462 jmp int_ret_from_sys_call
467 * sigreturn is special because it needs to restore all registers on return.
468 * This cannot be done with SYSRET, so use the IRET return path instead.
470 ENTRY(stub_rt_sigreturn)
473 CFI_ADJUST_CFA_OFFSET -8
476 FIXUP_TOP_OF_STACK %r11
477 call sys_rt_sigreturn
478 movq %rax,RAX(%rsp) # fixme, this could be done at the higher layer
480 jmp int_ret_from_sys_call
482 END(stub_rt_sigreturn)
485 * initial frame state for interrupts and exceptions
489 CFI_DEF_CFA rsp,SS+8-\ref
490 /*CFI_REL_OFFSET ss,SS-\ref*/
491 CFI_REL_OFFSET rsp,RSP-\ref
492 /*CFI_REL_OFFSET rflags,EFLAGS-\ref*/
493 /*CFI_REL_OFFSET cs,CS-\ref*/
494 CFI_REL_OFFSET rip,RIP-\ref
497 /* initial frame state for interrupts (and exceptions without error code) */
498 #define INTR_FRAME _frame RIP
499 /* initial frame state for exceptions with error code (and interrupts with
500 vector already pushed) */
501 #define XCPT_FRAME _frame ORIG_RAX
504 * Interrupt entry/exit.
506 * Interrupt entry points save only callee clobbered registers in fast path.
508 * Entry runs with interrupts off.
511 /* 0(%rsp): interrupt number */
512 .macro interrupt func
515 leaq -ARGOFFSET(%rsp),%rdi # arg1 for handler
517 CFI_ADJUST_CFA_OFFSET 8
518 CFI_REL_OFFSET rbp, 0
520 CFI_DEF_CFA_REGISTER rbp
524 1: incl %gs:pda_irqcount # RED-PEN should check preempt count
525 cmoveq %gs:pda_irqstackptr,%rsp
526 push %rbp # backlink for old unwinder
528 * We entered an interrupt context - irqs are off:
534 ENTRY(common_interrupt)
537 /* 0(%rsp): oldrsp-ARGOFFSET */
541 decl %gs:pda_irqcount
543 CFI_DEF_CFA_REGISTER rsp
544 CFI_ADJUST_CFA_OFFSET -8
546 GET_THREAD_INFO(%rcx)
547 testl $3,CS-ARGOFFSET(%rsp)
550 /* Interrupt came from user space */
552 * Has a correct top of stack, but a partial stack frame
553 * %rcx: thread info. Interrupts off.
555 retint_with_reschedule:
556 movl $_TIF_WORK_MASK,%edi
558 movl threadinfo_flags(%rcx),%edx
564 * The iretq could re-enable interrupts:
574 * The iretq could re-enable interrupts:
582 .section __ex_table,"a"
583 .quad iret_label,bad_iret
586 /* force a signal here? this matches i386 behaviour */
587 /* running with kernel gs */
589 movq $11,%rdi /* SIGSEGV */
595 /* edi: workmask, edx: work */
598 bt $TIF_NEED_RESCHED,%edx
603 CFI_ADJUST_CFA_OFFSET 8
606 CFI_ADJUST_CFA_OFFSET -8
607 GET_THREAD_INFO(%rcx)
613 testl $(_TIF_SIGPENDING|_TIF_NOTIFY_RESUME|_TIF_SINGLESTEP),%edx
618 movq $-1,ORIG_RAX(%rsp)
619 xorl %esi,%esi # oldset
620 movq %rsp,%rdi # &pt_regs
621 call do_notify_resume
625 movl $_TIF_NEED_RESCHED,%edi
626 GET_THREAD_INFO(%rcx)
629 #ifdef CONFIG_PREEMPT
630 /* Returning to kernel space. Check if we need preemption */
631 /* rcx: threadinfo. interrupts off. */
633 cmpl $0,threadinfo_preempt_count(%rcx)
634 jnz retint_restore_args
635 bt $TIF_NEED_RESCHED,threadinfo_flags(%rcx)
636 jnc retint_restore_args
637 bt $9,EFLAGS-ARGOFFSET(%rsp) /* interrupts off? */
638 jnc retint_restore_args
639 call preempt_schedule_irq
644 END(common_interrupt)
649 .macro apicinterrupt num,func
652 CFI_ADJUST_CFA_OFFSET 8
658 ENTRY(thermal_interrupt)
659 apicinterrupt THERMAL_APIC_VECTOR,smp_thermal_interrupt
660 END(thermal_interrupt)
662 ENTRY(threshold_interrupt)
663 apicinterrupt THRESHOLD_APIC_VECTOR,mce_threshold_interrupt
664 END(threshold_interrupt)
667 ENTRY(reschedule_interrupt)
668 apicinterrupt RESCHEDULE_VECTOR,smp_reschedule_interrupt
669 END(reschedule_interrupt)
671 .macro INVALIDATE_ENTRY num
672 ENTRY(invalidate_interrupt\num)
673 apicinterrupt INVALIDATE_TLB_VECTOR_START+\num,smp_invalidate_interrupt
674 END(invalidate_interrupt\num)
686 ENTRY(call_function_interrupt)
687 apicinterrupt CALL_FUNCTION_VECTOR,smp_call_function_interrupt
688 END(call_function_interrupt)
691 ENTRY(apic_timer_interrupt)
692 apicinterrupt LOCAL_TIMER_VECTOR,smp_apic_timer_interrupt
693 END(apic_timer_interrupt)
695 ENTRY(error_interrupt)
696 apicinterrupt ERROR_APIC_VECTOR,smp_error_interrupt
699 ENTRY(spurious_interrupt)
700 apicinterrupt SPURIOUS_APIC_VECTOR,smp_spurious_interrupt
701 END(spurious_interrupt)
704 * Exception entry points.
708 pushq $0 /* push error code/oldrax */
709 CFI_ADJUST_CFA_OFFSET 8
710 pushq %rax /* push real oldrax to the rdi slot */
711 CFI_ADJUST_CFA_OFFSET 8
717 .macro errorentry sym
720 CFI_ADJUST_CFA_OFFSET 8
726 /* error code is on the stack already */
727 /* handle NMI like exceptions that can happen everywhere */
728 .macro paranoidentry sym, ist=0, irqtrace=1
732 movl $MSR_GS_BASE,%ecx
740 movq %gs:pda_data_offset, %rbp
743 movq ORIG_RAX(%rsp),%rsi
744 movq $-1,ORIG_RAX(%rsp)
746 subq $EXCEPTION_STKSZ, per_cpu__init_tss + TSS_ist + (\ist - 1) * 8(%rbp)
750 addq $EXCEPTION_STKSZ, per_cpu__init_tss + TSS_ist + (\ist - 1) * 8(%rbp)
759 * "Paranoid" exit path from exception stack.
760 * Paranoid because this is used by NMIs and cannot take
761 * any kernel state for granted.
762 * We don't do kernel preemption checks here, because only
763 * NMI should be common and it does not enable IRQs and
764 * cannot get reschedule ticks.
766 * "trace" is 0 for the NMI handler only, because irq-tracing
767 * is fundamentally NMI-unsafe. (we cannot change the soft and
768 * hard flags at once, atomically)
770 .macro paranoidexit trace=1
771 /* ebx: no swapgs flag */
773 testl %ebx,%ebx /* swapgs needed? */
774 jnz paranoid_restore\trace
776 jnz paranoid_userspace\trace
777 paranoid_swapgs\trace:
780 paranoid_restore\trace:
783 paranoid_userspace\trace:
784 GET_THREAD_INFO(%rcx)
785 movl threadinfo_flags(%rcx),%ebx
786 andl $_TIF_WORK_MASK,%ebx
787 jz paranoid_swapgs\trace
788 movq %rsp,%rdi /* &pt_regs */
790 movq %rax,%rsp /* switch stack for scheduling */
791 testl $_TIF_NEED_RESCHED,%ebx
792 jnz paranoid_schedule\trace
793 movl %ebx,%edx /* arg3: thread flags */
798 xorl %esi,%esi /* arg2: oldset */
799 movq %rsp,%rdi /* arg1: &pt_regs */
800 call do_notify_resume
805 jmp paranoid_userspace\trace
806 paranoid_schedule\trace:
816 jmp paranoid_userspace\trace
821 * Exception entry point. This expects an error code/orig_rax on the stack
822 * and the exception handler in %rax.
826 /* rdi slot contains rax, oldrax contains error code */
829 CFI_ADJUST_CFA_OFFSET (14*8)
831 CFI_REL_OFFSET rsi,RSI
832 movq 14*8(%rsp),%rsi /* load rax from rdi slot */
834 CFI_REL_OFFSET rdx,RDX
836 CFI_REL_OFFSET rcx,RCX
837 movq %rsi,10*8(%rsp) /* store rax */
838 CFI_REL_OFFSET rax,RAX
844 CFI_REL_OFFSET r10,R10
846 CFI_REL_OFFSET r11,R11
848 CFI_REL_OFFSET rbx,RBX
850 CFI_REL_OFFSET rbp,RBP
852 CFI_REL_OFFSET r12,R12
854 CFI_REL_OFFSET r13,R13
856 CFI_REL_OFFSET r14,R14
858 CFI_REL_OFFSET r15,R15
867 movq ORIG_RAX(%rsp),%rsi /* get error code */
868 movq $-1,ORIG_RAX(%rsp)
870 /* ebx: no swapgs flag (1: don't need swapgs, 0: need it) */
876 GET_THREAD_INFO(%rcx)
879 movl threadinfo_flags(%rcx),%edx
880 movl $_TIF_WORK_MASK,%edi
884 * The iret might restore flags:
894 /* There are two places in the kernel that can potentially fault with
895 usergs. Handle them here. The exception handlers after
896 iret run with kernel gs again, so don't set the user space flag.
897 B stepping K8s sometimes report an truncated RIP for IRET
898 exceptions returning to compat mode. Check for these here too. */
899 leaq iret_label(%rip),%rbp
902 movl %ebp,%ebp /* zero extend */
905 cmpq $gs_change,RIP(%rsp)
910 /* Reload gs selector with exception handling */
911 /* edi: new selector */
915 CFI_ADJUST_CFA_OFFSET 8
920 2: mfence /* workaround */
923 CFI_ADJUST_CFA_OFFSET -8
926 ENDPROC(load_gs_index)
928 .section __ex_table,"a"
930 .quad gs_change,bad_gs
933 /* running with kernelgs */
935 swapgs /* switch back to user gs */
942 * Create a kernel thread.
944 * C extern interface:
945 * extern long kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
947 * asm input arguments:
948 * rdi: fn, rsi: arg, rdx: flags
952 FAKE_STACK_FRAME $child_rip
955 # rdi: flags, rsi: usp, rdx: will be &pt_regs
957 orq kernel_thread_flags(%rip),%rdi
970 * It isn't worth to check for reschedule here,
971 * so internally to the x86_64 port you can rely on kernel_thread()
972 * not to reschedule the child before returning, this avoids the need
973 * of hacks for example to fork off the per-CPU idle tasks.
974 * [Hopefully no generic code relies on the reschedule -AK]
980 ENDPROC(kernel_thread)
983 pushq $0 # fake return address
986 * Here we are in the child and the registers are set as they were
987 * at kernel_thread() invocation in the parent.
999 * execve(). This function needs to use IRET, not SYSRET, to set up all state properly.
1001 * C extern interface:
1002 * extern long execve(char *name, char **argv, char **envp)
1004 * asm input arguments:
1005 * rdi: name, rsi: argv, rdx: envp
1007 * We want to fallback into:
1008 * extern long sys_execve(char *name, char **argv,char **envp, struct pt_regs regs)
1010 * do_sys_execve asm fallback arguments:
1011 * rdi: name, rsi: argv, rdx: envp, fake frame on the stack
1018 movq %rax, RAX(%rsp)
1021 je int_ret_from_sys_call
1028 KPROBE_ENTRY(page_fault)
1029 errorentry do_page_fault
1033 ENTRY(coprocessor_error)
1034 zeroentry do_coprocessor_error
1035 END(coprocessor_error)
1037 ENTRY(simd_coprocessor_error)
1038 zeroentry do_simd_coprocessor_error
1039 END(simd_coprocessor_error)
1041 ENTRY(device_not_available)
1042 zeroentry math_state_restore
1043 END(device_not_available)
1045 /* runs on exception stack */
1049 CFI_ADJUST_CFA_OFFSET 8
1050 paranoidentry do_debug, DEBUG_STACK
1055 /* runs on exception stack */
1059 CFI_ADJUST_CFA_OFFSET 8
1060 paranoidentry do_nmi, 0, 0
1061 #ifdef CONFIG_TRACE_IRQFLAGS
1073 CFI_ADJUST_CFA_OFFSET 8
1074 paranoidentry do_int3, DEBUG_STACK
1081 zeroentry do_overflow
1089 zeroentry do_invalid_op
1092 ENTRY(coprocessor_segment_overrun)
1093 zeroentry do_coprocessor_segment_overrun
1094 END(coprocessor_segment_overrun)
1097 zeroentry do_reserved
1100 /* runs on exception stack */
1103 paranoidentry do_double_fault
1109 errorentry do_invalid_TSS
1112 ENTRY(segment_not_present)
1113 errorentry do_segment_not_present
1114 END(segment_not_present)
1116 /* runs on exception stack */
1117 ENTRY(stack_segment)
1119 paranoidentry do_stack_segment
1124 KPROBE_ENTRY(general_protection)
1125 errorentry do_general_protection
1126 END(general_protection)
1129 ENTRY(alignment_check)
1130 errorentry do_alignment_check
1131 END(alignment_check)
1134 zeroentry do_divide_error
1137 ENTRY(spurious_interrupt_bug)
1138 zeroentry do_spurious_interrupt_bug
1139 END(spurious_interrupt_bug)
1141 #ifdef CONFIG_X86_MCE
1142 /* runs on exception stack */
1143 ENTRY(machine_check)
1146 CFI_ADJUST_CFA_OFFSET 8
1147 paranoidentry do_machine_check
1153 /* Call softirq on interrupt stack. Interrupts are off. */
1157 CFI_ADJUST_CFA_OFFSET 8
1158 CFI_REL_OFFSET rbp,0
1160 CFI_DEF_CFA_REGISTER rbp
1161 incl %gs:pda_irqcount
1162 cmove %gs:pda_irqstackptr,%rsp
1163 push %rbp # backlink for old unwinder
1166 CFI_DEF_CFA_REGISTER rsp
1167 CFI_ADJUST_CFA_OFFSET -8
1168 decl %gs:pda_irqcount
1171 ENDPROC(call_softirq)
1173 #ifdef CONFIG_STACK_UNWIND
1174 ENTRY(arch_unwind_init_running)
1176 movq %r15, R15(%rdi)
1177 movq %r14, R14(%rdi)
1179 movq %r13, R13(%rdi)
1180 movq %r12, R12(%rdi)
1182 movq %rbp, RBP(%rdi)
1183 movq %rbx, RBX(%rdi)
1185 movq %rax, R11(%rdi)
1186 movq %rax, R10(%rdi)
1189 movq %rax, RAX(%rdi)
1190 movq %rax, RCX(%rdi)
1191 movq %rax, RDX(%rdi)
1192 movq %rax, RSI(%rdi)
1193 movq %rax, RDI(%rdi)
1194 movq %rax, ORIG_RAX(%rdi)
1195 movq %rcx, RIP(%rdi)
1197 movq $__KERNEL_CS, CS(%rdi)
1198 movq %rax, EFLAGS(%rdi)
1199 movq %rcx, RSP(%rdi)
1200 movq $__KERNEL_DS, SS(%rdi)
1203 ENDPROC(arch_unwind_init_running)