| blob | 8a445a0c989e095bc84557861d4a4e73e09e3e90 |
1 /*
2 * linux/arch/x86_64/entry.S
3 *
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>
7 */
9 /*
10 * entry.S contains the system-call and fault low-level handling routines.
11 *
12 * NOTE: This code handles signal-recognition, which happens every time
13 * after an interrupt and after each system call.
14 *
15 * Normal syscalls and interrupts don't save a full stack frame, this is
16 * only done for syscall tracing, signals or fork/exec et.al.
17 *
18 * A note on terminology:
19 * - top of stack: Architecture defined interrupt frame from SS to RIP
20 * at the top of the kernel process stack.
21 * - partial stack frame: partially saved registers up to R11.
22 * - full stack frame: Like partial stack frame, but all register saved.
23 *
24 * Some macro usage:
25 * - CFI macros are used to generate dwarf2 unwind information for better
26 * backtraces. They don't change any code.
27 * - SAVE_ALL/RESTORE_ALL - Save/restore all registers
28 * - SAVE_ARGS/RESTORE_ARGS - Save/restore registers that C functions modify.
29 * There are unfortunately lots of special cases where some registers
30 * not touched. The macro is a big mess that should be cleaned up.
31 * - SAVE_REST/RESTORE_REST - Handle the registers not saved by SAVE_ARGS.
32 * Gives a full stack frame.
33 * - ENTRY/END Define functions in the symbol table.
34 * - FIXUP_TOP_OF_STACK/RESTORE_TOP_OF_STACK - Fix up the hardware stack
35 * frame that is otherwise undefined after a SYSCALL
36 * - TRACE_IRQ_* - Trace hard interrupt state for lock debugging.
37 * - errorentry/paranoidentry/zeroentry - Define exception entry points.
38 */
40 #include <linux/linkage.h>
41 #include <asm/segment.h>
42 #include <asm/cache.h>
43 #include <asm/errno.h>
44 #include <asm/dwarf2.h>
45 #include <asm/calling.h>
46 #include <asm/asm-offsets.h>
47 #include <asm/msr.h>
48 #include <asm/unistd.h>
49 #include <asm/thread_info.h>
50 #include <asm/hw_irq.h>
51 #include <asm/page_types.h>
52 #include <asm/irqflags.h>
53 #include <asm/paravirt.h>
54 #include <asm/ftrace.h>
55 #include <asm/percpu.h>
57 /* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */
58 #include <linux/elf-em.h>
59 #define AUDIT_ARCH_X86_64 (EM_X86_64|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE)
60 #define __AUDIT_ARCH_64BIT 0x80000000
61 #define __AUDIT_ARCH_LE 0x40000000
63 .code64
64 .section .entry.text, "ax"
66 #ifdef CONFIG_FUNCTION_TRACER
67 #ifdef CONFIG_DYNAMIC_FTRACE
68 ENTRY(mcount)
69 retq
70 END(mcount)
72 ENTRY(ftrace_caller)
73 cmpl $0, function_trace_stop
74 jne ftrace_stub
76 MCOUNT_SAVE_FRAME
78 movq 0x38(%rsp), %rdi
79 movq 8(%rbp), %rsi
80 subq $MCOUNT_INSN_SIZE, %rdi
82 GLOBAL(ftrace_call)
83 call ftrace_stub
85 MCOUNT_RESTORE_FRAME
87 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
88 GLOBAL(ftrace_graph_call)
89 jmp ftrace_stub
90 #endif
92 GLOBAL(ftrace_stub)
93 retq
94 END(ftrace_caller)
96 #else /* ! CONFIG_DYNAMIC_FTRACE */
97 ENTRY(mcount)
98 cmpl $0, function_trace_stop
99 jne ftrace_stub
101 cmpq $ftrace_stub, ftrace_trace_function
102 jnz trace
104 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
105 cmpq $ftrace_stub, ftrace_graph_return
106 jnz ftrace_graph_caller
108 cmpq $ftrace_graph_entry_stub, ftrace_graph_entry
109 jnz ftrace_graph_caller
110 #endif
112 GLOBAL(ftrace_stub)
113 retq
115 trace:
116 MCOUNT_SAVE_FRAME
118 movq 0x38(%rsp), %rdi
119 movq 8(%rbp), %rsi
120 subq $MCOUNT_INSN_SIZE, %rdi
122 call *ftrace_trace_function
124 MCOUNT_RESTORE_FRAME
126 jmp ftrace_stub
127 END(mcount)
128 #endif /* CONFIG_DYNAMIC_FTRACE */
129 #endif /* CONFIG_FUNCTION_TRACER */
131 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
132 ENTRY(ftrace_graph_caller)
133 cmpl $0, function_trace_stop
134 jne ftrace_stub
136 MCOUNT_SAVE_FRAME
138 leaq 8(%rbp), %rdi
139 movq 0x38(%rsp), %rsi
140 movq (%rbp), %rdx
141 subq $MCOUNT_INSN_SIZE, %rsi
143 call prepare_ftrace_return
145 MCOUNT_RESTORE_FRAME
147 retq
148 END(ftrace_graph_caller)
150 GLOBAL(return_to_handler)
151 subq $24, %rsp
153 /* Save the return values */
154 movq %rax, (%rsp)
155 movq %rdx, 8(%rsp)
156 movq %rbp, %rdi
158 call ftrace_return_to_handler
160 movq %rax, %rdi
161 movq 8(%rsp), %rdx
162 movq (%rsp), %rax
163 addq $24, %rsp
164 jmp *%rdi
165 #endif
168 #ifndef CONFIG_PREEMPT
169 #define retint_kernel retint_restore_args
170 #endif
172 #ifdef CONFIG_PARAVIRT
173 ENTRY(native_usergs_sysret64)
174 swapgs
175 sysretq
176 ENDPROC(native_usergs_sysret64)
177 #endif /* CONFIG_PARAVIRT */
180 .macro TRACE_IRQS_IRETQ offset=ARGOFFSET
181 #ifdef CONFIG_TRACE_IRQFLAGS
182 bt $9,EFLAGS-\offset(%rsp) /* interrupts off? */
183 jnc 1f
184 TRACE_IRQS_ON
185 1:
186 #endif
187 .endm
189 /*
190 * C code is not supposed to know about undefined top of stack. Every time
191 * a C function with an pt_regs argument is called from the SYSCALL based
192 * fast path FIXUP_TOP_OF_STACK is needed.
193 * RESTORE_TOP_OF_STACK syncs the syscall state after any possible ptregs
194 * manipulation.
195 */
197 /* %rsp:at FRAMEEND */
198 .macro FIXUP_TOP_OF_STACK tmp offset=0
199 movq PER_CPU_VAR(old_rsp),\tmp
200 movq \tmp,RSP+\offset(%rsp)
201 movq $__USER_DS,SS+\offset(%rsp)
202 movq $__USER_CS,CS+\offset(%rsp)
203 movq $-1,RCX+\offset(%rsp)
204 movq R11+\offset(%rsp),\tmp /* get eflags */
205 movq \tmp,EFLAGS+\offset(%rsp)
206 .endm
208 .macro RESTORE_TOP_OF_STACK tmp offset=0
209 movq RSP+\offset(%rsp),\tmp
210 movq \tmp,PER_CPU_VAR(old_rsp)
211 movq EFLAGS+\offset(%rsp),\tmp
212 movq \tmp,R11+\offset(%rsp)
213 .endm
215 .macro FAKE_STACK_FRAME child_rip
216 /* push in order ss, rsp, eflags, cs, rip */
217 xorl %eax, %eax
218 pushq_cfi $__KERNEL_DS /* ss */
219 /*CFI_REL_OFFSET ss,0*/
220 pushq_cfi %rax /* rsp */
221 CFI_REL_OFFSET rsp,0
222 pushq_cfi $X86_EFLAGS_IF /* eflags - interrupts on */
223 /*CFI_REL_OFFSET rflags,0*/
224 pushq_cfi $__KERNEL_CS /* cs */
225 /*CFI_REL_OFFSET cs,0*/
226 pushq_cfi \child_rip /* rip */
227 CFI_REL_OFFSET rip,0
228 pushq_cfi %rax /* orig rax */
229 .endm
231 .macro UNFAKE_STACK_FRAME
232 addq $8*6, %rsp
233 CFI_ADJUST_CFA_OFFSET -(6*8)
234 .endm
236 /*
237 * initial frame state for interrupts (and exceptions without error code)
238 */
239 .macro EMPTY_FRAME start=1 offset=0
240 .if \start
241 CFI_STARTPROC simple
242 CFI_SIGNAL_FRAME
243 CFI_DEF_CFA rsp,8+\offset
244 .else
245 CFI_DEF_CFA_OFFSET 8+\offset
246 .endif
247 .endm
249 /*
250 * initial frame state for interrupts (and exceptions without error code)
251 */
252 .macro INTR_FRAME start=1 offset=0
253 EMPTY_FRAME \start, SS+8+\offset-RIP
254 /*CFI_REL_OFFSET ss, SS+\offset-RIP*/
255 CFI_REL_OFFSET rsp, RSP+\offset-RIP
256 /*CFI_REL_OFFSET rflags, EFLAGS+\offset-RIP*/
257 /*CFI_REL_OFFSET cs, CS+\offset-RIP*/
258 CFI_REL_OFFSET rip, RIP+\offset-RIP
259 .endm
261 /*
262 * initial frame state for exceptions with error code (and interrupts
263 * with vector already pushed)
264 */
265 .macro XCPT_FRAME start=1 offset=0
266 INTR_FRAME \start, RIP+\offset-ORIG_RAX
267 /*CFI_REL_OFFSET orig_rax, ORIG_RAX-ORIG_RAX*/
268 .endm
270 /*
271 * frame that enables calling into C.
272 */
273 .macro PARTIAL_FRAME start=1 offset=0
274 XCPT_FRAME \start, ORIG_RAX+\offset-ARGOFFSET
275 CFI_REL_OFFSET rdi, RDI+\offset-ARGOFFSET
276 CFI_REL_OFFSET rsi, RSI+\offset-ARGOFFSET
277 CFI_REL_OFFSET rdx, RDX+\offset-ARGOFFSET
278 CFI_REL_OFFSET rcx, RCX+\offset-ARGOFFSET
279 CFI_REL_OFFSET rax, RAX+\offset-ARGOFFSET
280 CFI_REL_OFFSET r8, R8+\offset-ARGOFFSET
281 CFI_REL_OFFSET r9, R9+\offset-ARGOFFSET
282 CFI_REL_OFFSET r10, R10+\offset-ARGOFFSET
283 CFI_REL_OFFSET r11, R11+\offset-ARGOFFSET
284 .endm
286 /*
287 * frame that enables passing a complete pt_regs to a C function.
288 */
289 .macro DEFAULT_FRAME start=1 offset=0
290 PARTIAL_FRAME \start, R11+\offset-R15
291 CFI_REL_OFFSET rbx, RBX+\offset
292 CFI_REL_OFFSET rbp, RBP+\offset
293 CFI_REL_OFFSET r12, R12+\offset
294 CFI_REL_OFFSET r13, R13+\offset
295 CFI_REL_OFFSET r14, R14+\offset
296 CFI_REL_OFFSET r15, R15+\offset
297 .endm
299 /* save partial stack frame */
300 .pushsection .kprobes.text, "ax"
301 ENTRY(save_args)
302 XCPT_FRAME
303 cld
304 /*
305 * start from rbp in pt_regs and jump over
306 * return address.
307 */
308 movq_cfi rdi, RDI+8-RBP
309 movq_cfi rsi, RSI+8-RBP
310 movq_cfi rdx, RDX+8-RBP
311 movq_cfi rcx, RCX+8-RBP
312 movq_cfi rax, RAX+8-RBP
313 movq_cfi r8, R8+8-RBP
314 movq_cfi r9, R9+8-RBP
315 movq_cfi r10, R10+8-RBP
316 movq_cfi r11, R11+8-RBP
318 leaq -RBP+8(%rsp),%rdi /* arg1 for handler */
319 movq_cfi rbp, 8 /* push %rbp */
320 leaq 8(%rsp), %rbp /* mov %rsp, %ebp */
321 testl $3, CS(%rdi)
322 je 1f
323 SWAPGS
324 /*
325 * irq_count is used to check if a CPU is already on an interrupt stack
326 * or not. While this is essentially redundant with preempt_count it is
327 * a little cheaper to use a separate counter in the PDA (short of
328 * moving irq_enter into assembly, which would be too much work)
329 */
330 1: incl PER_CPU_VAR(irq_count)
331 jne 2f
332 popq_cfi %rax /* move return address... */
333 mov PER_CPU_VAR(irq_stack_ptr),%rsp
334 EMPTY_FRAME 0
335 pushq_cfi %rbp /* backlink for unwinder */
336 pushq_cfi %rax /* ... to the new stack */
337 /*
338 * We entered an interrupt context - irqs are off:
339 */
340 2: TRACE_IRQS_OFF
341 ret
342 CFI_ENDPROC
343 END(save_args)
344 .popsection
346 ENTRY(save_rest)
347 PARTIAL_FRAME 1 REST_SKIP+8
348 movq 5*8+16(%rsp), %r11 /* save return address */
349 movq_cfi rbx, RBX+16
350 movq_cfi rbp, RBP+16
351 movq_cfi r12, R12+16
352 movq_cfi r13, R13+16
353 movq_cfi r14, R14+16
354 movq_cfi r15, R15+16
355 movq %r11, 8(%rsp) /* return address */
356 FIXUP_TOP_OF_STACK %r11, 16
357 ret
358 CFI_ENDPROC
359 END(save_rest)
361 /* save complete stack frame */
362 .pushsection .kprobes.text, "ax"
363 ENTRY(save_paranoid)
364 XCPT_FRAME 1 RDI+8
365 cld
366 movq_cfi rdi, RDI+8
367 movq_cfi rsi, RSI+8
368 movq_cfi rdx, RDX+8
369 movq_cfi rcx, RCX+8
370 movq_cfi rax, RAX+8
371 movq_cfi r8, R8+8
372 movq_cfi r9, R9+8
373 movq_cfi r10, R10+8
374 movq_cfi r11, R11+8
375 movq_cfi rbx, RBX+8
376 movq_cfi rbp, RBP+8
377 movq_cfi r12, R12+8
378 movq_cfi r13, R13+8
379 movq_cfi r14, R14+8
380 movq_cfi r15, R15+8
381 movl $1,%ebx
382 movl $MSR_GS_BASE,%ecx
383 rdmsr
384 testl %edx,%edx
385 js 1f /* negative -> in kernel */
386 SWAPGS
387 xorl %ebx,%ebx
388 1: ret
389 CFI_ENDPROC
390 END(save_paranoid)
391 .popsection
393 /*
394 * A newly forked process directly context switches into this address.
395 *
396 * rdi: prev task we switched from
397 */
398 ENTRY(ret_from_fork)
399 DEFAULT_FRAME
401 LOCK ; btr $TIF_FORK,TI_flags(%r8)
403 pushq_cfi kernel_eflags(%rip)
404 popfq_cfi # reset kernel eflags
406 call schedule_tail # rdi: 'prev' task parameter
408 GET_THREAD_INFO(%rcx)
410 RESTORE_REST
412 testl $3, CS-ARGOFFSET(%rsp) # from kernel_thread?
413 je int_ret_from_sys_call
415 testl $_TIF_IA32, TI_flags(%rcx) # 32-bit compat task needs IRET
416 jnz int_ret_from_sys_call
418 RESTORE_TOP_OF_STACK %rdi, -ARGOFFSET
419 jmp ret_from_sys_call # go to the SYSRET fastpath
421 CFI_ENDPROC
422 END(ret_from_fork)
424 /*
425 * System call entry. Up to 6 arguments in registers are supported.
426 *
427 * SYSCALL does not save anything on the stack and does not change the
428 * stack pointer.
429 */
431 /*
432 * Register setup:
433 * rax system call number
434 * rdi arg0
435 * rcx return address for syscall/sysret, C arg3
436 * rsi arg1
437 * rdx arg2
438 * r10 arg3 (--> moved to rcx for C)
439 * r8 arg4
440 * r9 arg5
441 * r11 eflags for syscall/sysret, temporary for C
442 * r12-r15,rbp,rbx saved by C code, not touched.
443 *
444 * Interrupts are off on entry.
445 * Only called from user space.
446 *
447 * XXX if we had a free scratch register we could save the RSP into the stack frame
448 * and report it properly in ps. Unfortunately we haven't.
449 *
450 * When user can change the frames always force IRET. That is because
451 * it deals with uncanonical addresses better. SYSRET has trouble
452 * with them due to bugs in both AMD and Intel CPUs.
453 */
455 ENTRY(system_call)
456 CFI_STARTPROC simple
457 CFI_SIGNAL_FRAME
458 CFI_DEF_CFA rsp,KERNEL_STACK_OFFSET
459 CFI_REGISTER rip,rcx
460 /*CFI_REGISTER rflags,r11*/
461 SWAPGS_UNSAFE_STACK
462 /*
463 * A hypervisor implementation might want to use a label
464 * after the swapgs, so that it can do the swapgs
465 * for the guest and jump here on syscall.
466 */
467 ENTRY(system_call_after_swapgs)
469 movq %rsp,PER_CPU_VAR(old_rsp)
470 movq PER_CPU_VAR(kernel_stack),%rsp
471 /*
472 * No need to follow this irqs off/on section - it's straight
473 * and short:
474 */
475 ENABLE_INTERRUPTS(CLBR_NONE)
476 SAVE_ARGS 8,1
477 movq %rax,ORIG_RAX-ARGOFFSET(%rsp)
478 movq %rcx,RIP-ARGOFFSET(%rsp)
479 CFI_REL_OFFSET rip,RIP-ARGOFFSET
480 GET_THREAD_INFO(%rcx)
481 testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%rcx)
482 jnz tracesys
483 system_call_fastpath:
484 cmpq $__NR_syscall_max,%rax
485 ja badsys
486 movq %r10,%rcx
487 call *sys_call_table(,%rax,8) # XXX: rip relative
488 movq %rax,RAX-ARGOFFSET(%rsp)
489 /*
490 * Syscall return path ending with SYSRET (fast path)
491 * Has incomplete stack frame and undefined top of stack.
492 */
493 ret_from_sys_call:
494 movl $_TIF_ALLWORK_MASK,%edi
495 /* edi: flagmask */
496 sysret_check:
497 LOCKDEP_SYS_EXIT
498 GET_THREAD_INFO(%rcx)
499 DISABLE_INTERRUPTS(CLBR_NONE)
500 TRACE_IRQS_OFF
501 movl TI_flags(%rcx),%edx
502 andl %edi,%edx
503 jnz sysret_careful
504 CFI_REMEMBER_STATE
505 /*
506 * sysretq will re-enable interrupts:
507 */
508 TRACE_IRQS_ON
509 movq RIP-ARGOFFSET(%rsp),%rcx
510 CFI_REGISTER rip,rcx
511 RESTORE_ARGS 0,-ARG_SKIP,1
512 /*CFI_REGISTER rflags,r11*/
513 movq PER_CPU_VAR(old_rsp), %rsp
514 USERGS_SYSRET64
516 CFI_RESTORE_STATE
517 /* Handle reschedules */
518 /* edx: work, edi: workmask */
519 sysret_careful:
520 bt $TIF_NEED_RESCHED,%edx
521 jnc sysret_signal
522 TRACE_IRQS_ON
523 ENABLE_INTERRUPTS(CLBR_NONE)
524 pushq_cfi %rdi
525 call schedule
526 popq_cfi %rdi
527 jmp sysret_check
529 /* Handle a signal */
530 sysret_signal:
531 TRACE_IRQS_ON
532 ENABLE_INTERRUPTS(CLBR_NONE)
533 #ifdef CONFIG_AUDITSYSCALL
534 bt $TIF_SYSCALL_AUDIT,%edx
535 jc sysret_audit
536 #endif
537 /*
538 * We have a signal, or exit tracing or single-step.
539 * These all wind up with the iret return path anyway,
540 * so just join that path right now.
541 */
542 FIXUP_TOP_OF_STACK %r11, -ARGOFFSET
543 jmp int_check_syscall_exit_work
545 badsys:
546 movq $-ENOSYS,RAX-ARGOFFSET(%rsp)
547 jmp ret_from_sys_call
549 #ifdef CONFIG_AUDITSYSCALL
550 /*
551 * Fast path for syscall audit without full syscall trace.
552 * We just call audit_syscall_entry() directly, and then
553 * jump back to the normal fast path.
554 */
555 auditsys:
556 movq %r10,%r9 /* 6th arg: 4th syscall arg */
557 movq %rdx,%r8 /* 5th arg: 3rd syscall arg */
558 movq %rsi,%rcx /* 4th arg: 2nd syscall arg */
559 movq %rdi,%rdx /* 3rd arg: 1st syscall arg */
560 movq %rax,%rsi /* 2nd arg: syscall number */
561 movl $AUDIT_ARCH_X86_64,%edi /* 1st arg: audit arch */
562 call audit_syscall_entry
563 LOAD_ARGS 0 /* reload call-clobbered registers */
564 jmp system_call_fastpath
566 /*
567 * Return fast path for syscall audit. Call audit_syscall_exit()
568 * directly and then jump back to the fast path with TIF_SYSCALL_AUDIT
569 * masked off.
570 */
571 sysret_audit:
572 movq RAX-ARGOFFSET(%rsp),%rsi /* second arg, syscall return value */
573 cmpq $0,%rsi /* is it < 0? */
574 setl %al /* 1 if so, 0 if not */
575 movzbl %al,%edi /* zero-extend that into %edi */
576 inc %edi /* first arg, 0->1(AUDITSC_SUCCESS), 1->2(AUDITSC_FAILURE) */
577 call audit_syscall_exit
578 movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),%edi
579 jmp sysret_check
580 #endif /* CONFIG_AUDITSYSCALL */
582 /* Do syscall tracing */
583 tracesys:
584 #ifdef CONFIG_AUDITSYSCALL
585 testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%rcx)
586 jz auditsys
587 #endif
588 SAVE_REST
589 movq $-ENOSYS,RAX(%rsp) /* ptrace can change this for a bad syscall */
590 FIXUP_TOP_OF_STACK %rdi
591 movq %rsp,%rdi
592 call syscall_trace_enter
593 /*
594 * Reload arg registers from stack in case ptrace changed them.
595 * We don't reload %rax because syscall_trace_enter() returned
596 * the value it wants us to use in the table lookup.
597 */
598 LOAD_ARGS ARGOFFSET, 1
599 RESTORE_REST
600 cmpq $__NR_syscall_max,%rax
601 ja int_ret_from_sys_call /* RAX(%rsp) set to -ENOSYS above */
602 movq %r10,%rcx /* fixup for C */
603 call *sys_call_table(,%rax,8)
604 movq %rax,RAX-ARGOFFSET(%rsp)
605 /* Use IRET because user could have changed frame */
607 /*
608 * Syscall return path ending with IRET.
609 * Has correct top of stack, but partial stack frame.
610 */
611 GLOBAL(int_ret_from_sys_call)
612 DISABLE_INTERRUPTS(CLBR_NONE)
613 TRACE_IRQS_OFF
614 testl $3,CS-ARGOFFSET(%rsp)
615 je retint_restore_args
616 movl $_TIF_ALLWORK_MASK,%edi
617 /* edi: mask to check */
618 GLOBAL(int_with_check)
619 LOCKDEP_SYS_EXIT_IRQ
620 GET_THREAD_INFO(%rcx)
621 movl TI_flags(%rcx),%edx
622 andl %edi,%edx
623 jnz int_careful
624 andl $~TS_COMPAT,TI_status(%rcx)
625 jmp retint_swapgs
627 /* Either reschedule or signal or syscall exit tracking needed. */
628 /* First do a reschedule test. */
629 /* edx: work, edi: workmask */
630 int_careful:
631 bt $TIF_NEED_RESCHED,%edx
632 jnc int_very_careful
633 TRACE_IRQS_ON
634 ENABLE_INTERRUPTS(CLBR_NONE)
635 pushq_cfi %rdi
636 call schedule
637 popq_cfi %rdi
638 DISABLE_INTERRUPTS(CLBR_NONE)
639 TRACE_IRQS_OFF
640 jmp int_with_check
642 /* handle signals and tracing -- both require a full stack frame */
643 int_very_careful:
644 TRACE_IRQS_ON
645 ENABLE_INTERRUPTS(CLBR_NONE)
646 int_check_syscall_exit_work:
647 SAVE_REST
648 /* Check for syscall exit trace */
649 testl $_TIF_WORK_SYSCALL_EXIT,%edx
650 jz int_signal
651 pushq_cfi %rdi
652 leaq 8(%rsp),%rdi # &ptregs -> arg1
653 call syscall_trace_leave
654 popq_cfi %rdi
655 andl $~(_TIF_WORK_SYSCALL_EXIT|_TIF_SYSCALL_EMU),%edi
656 jmp int_restore_rest
658 int_signal:
659 testl $_TIF_DO_NOTIFY_MASK,%edx
660 jz 1f
661 movq %rsp,%rdi # &ptregs -> arg1
662 xorl %esi,%esi # oldset -> arg2
663 call do_notify_resume
664 1: movl $_TIF_WORK_MASK,%edi
665 int_restore_rest:
666 RESTORE_REST
667 DISABLE_INTERRUPTS(CLBR_NONE)
668 TRACE_IRQS_OFF
669 jmp int_with_check
670 CFI_ENDPROC
671 END(system_call)
673 /*
674 * Certain special system calls that need to save a complete full stack frame.
675 */
676 .macro PTREGSCALL label,func,arg
677 ENTRY(\label)
678 PARTIAL_FRAME 1 8 /* offset 8: return address */
679 subq $REST_SKIP, %rsp
680 CFI_ADJUST_CFA_OFFSET REST_SKIP
681 call save_rest
682 DEFAULT_FRAME 0 8 /* offset 8: return address */
683 leaq 8(%rsp), \arg /* pt_regs pointer */
684 call \func
685 jmp ptregscall_common
686 CFI_ENDPROC
687 END(\label)
688 .endm
690 PTREGSCALL stub_clone, sys_clone, %r8
691 PTREGSCALL stub_fork, sys_fork, %rdi
692 PTREGSCALL stub_vfork, sys_vfork, %rdi
693 PTREGSCALL stub_sigaltstack, sys_sigaltstack, %rdx
694 PTREGSCALL stub_iopl, sys_iopl, %rsi
696 ENTRY(ptregscall_common)
697 DEFAULT_FRAME 1 8 /* offset 8: return address */
698 RESTORE_TOP_OF_STACK %r11, 8
699 movq_cfi_restore R15+8, r15
700 movq_cfi_restore R14+8, r14
701 movq_cfi_restore R13+8, r13
702 movq_cfi_restore R12+8, r12
703 movq_cfi_restore RBP+8, rbp
704 movq_cfi_restore RBX+8, rbx
705 ret $REST_SKIP /* pop extended registers */
706 CFI_ENDPROC
707 END(ptregscall_common)
709 ENTRY(stub_execve)
710 CFI_STARTPROC
711 addq $8, %rsp
712 PARTIAL_FRAME 0
713 SAVE_REST
714 FIXUP_TOP_OF_STACK %r11
715 movq %rsp, %rcx
716 call sys_execve
717 RESTORE_TOP_OF_STACK %r11
718 movq %rax,RAX(%rsp)
719 RESTORE_REST
720 jmp int_ret_from_sys_call
721 CFI_ENDPROC
722 END(stub_execve)
724 /*
725 * sigreturn is special because it needs to restore all registers on return.
726 * This cannot be done with SYSRET, so use the IRET return path instead.
727 */
728 ENTRY(stub_rt_sigreturn)
729 CFI_STARTPROC
730 addq $8, %rsp
731 PARTIAL_FRAME 0
732 SAVE_REST
733 movq %rsp,%rdi
734 FIXUP_TOP_OF_STACK %r11
735 call sys_rt_sigreturn
736 movq %rax,RAX(%rsp) # fixme, this could be done at the higher layer
737 RESTORE_REST
738 jmp int_ret_from_sys_call
739 CFI_ENDPROC
740 END(stub_rt_sigreturn)
742 /*
743 * Build the entry stubs and pointer table with some assembler magic.
744 * We pack 7 stubs into a single 32-byte chunk, which will fit in a
745 * single cache line on all modern x86 implementations.
746 */
747 .section .init.rodata,"a"
748 ENTRY(interrupt)
749 .section .entry.text
750 .p2align 5
751 .p2align CONFIG_X86_L1_CACHE_SHIFT
752 ENTRY(irq_entries_start)
753 INTR_FRAME
754 vector=FIRST_EXTERNAL_VECTOR
755 .rept (NR_VECTORS-FIRST_EXTERNAL_VECTOR+6)/7
756 .balign 32
757 .rept 7
758 .if vector < NR_VECTORS
759 .if vector <> FIRST_EXTERNAL_VECTOR
760 CFI_ADJUST_CFA_OFFSET -8
761 .endif
762 1: pushq_cfi $(~vector+0x80) /* Note: always in signed byte range */
763 .if ((vector-FIRST_EXTERNAL_VECTOR)%7) <> 6
764 jmp 2f
765 .endif
766 .previous
767 .quad 1b
768 .section .entry.text
769 vector=vector+1
770 .endif
771 .endr
772 2: jmp common_interrupt
773 .endr
774 CFI_ENDPROC
775 END(irq_entries_start)
777 .previous
778 END(interrupt)
779 .previous
781 /*
782 * Interrupt entry/exit.
783 *
784 * Interrupt entry points save only callee clobbered registers in fast path.
785 *
786 * Entry runs with interrupts off.
787 */
789 /* 0(%rsp): ~(interrupt number) */
790 .macro interrupt func
791 /* reserve pt_regs for scratch regs and rbp */
792 subq $ORIG_RAX-RBP, %rsp
793 CFI_ADJUST_CFA_OFFSET ORIG_RAX-RBP
794 call save_args
795 PARTIAL_FRAME 0
796 call \func
797 .endm
799 /*
800 * Interrupt entry/exit should be protected against kprobes
801 */
802 .pushsection .kprobes.text, "ax"
803 /*
804 * The interrupt stubs push (~vector+0x80) onto the stack and
805 * then jump to common_interrupt.
806 */
807 .p2align CONFIG_X86_L1_CACHE_SHIFT
808 common_interrupt:
809 XCPT_FRAME
810 addq $-0x80,(%rsp) /* Adjust vector to [-256,-1] range */
811 interrupt do_IRQ
812 /* 0(%rsp): old_rsp-ARGOFFSET */
813 ret_from_intr:
814 DISABLE_INTERRUPTS(CLBR_NONE)
815 TRACE_IRQS_OFF
816 decl PER_CPU_VAR(irq_count)
817 leaveq
819 CFI_RESTORE rbp
820 CFI_DEF_CFA_REGISTER rsp
821 CFI_ADJUST_CFA_OFFSET -8
823 /* we did not save rbx, restore only from ARGOFFSET */
824 addq $8, %rsp
825 CFI_ADJUST_CFA_OFFSET -8
826 exit_intr:
827 GET_THREAD_INFO(%rcx)
828 testl $3,CS-ARGOFFSET(%rsp)
829 je retint_kernel
831 /* Interrupt came from user space */
832 /*
833 * Has a correct top of stack, but a partial stack frame
834 * %rcx: thread info. Interrupts off.
835 */
836 retint_with_reschedule:
837 movl $_TIF_WORK_MASK,%edi
838 retint_check:
839 LOCKDEP_SYS_EXIT_IRQ
840 movl TI_flags(%rcx),%edx
841 andl %edi,%edx
842 CFI_REMEMBER_STATE
843 jnz retint_careful
845 retint_swapgs: /* return to user-space */
846 /*
847 * The iretq could re-enable interrupts:
848 */
849 DISABLE_INTERRUPTS(CLBR_ANY)
850 TRACE_IRQS_IRETQ
851 SWAPGS
852 jmp restore_args
854 retint_restore_args: /* return to kernel space */
855 DISABLE_INTERRUPTS(CLBR_ANY)
856 /*
857 * The iretq could re-enable interrupts:
858 */
859 TRACE_IRQS_IRETQ
860 restore_args:
861 RESTORE_ARGS 0,8,0
863 irq_return:
864 INTERRUPT_RETURN
866 .section __ex_table, "a"
867 .quad irq_return, bad_iret
868 .previous
870 #ifdef CONFIG_PARAVIRT
871 ENTRY(native_iret)
872 iretq
874 .section __ex_table,"a"
875 .quad native_iret, bad_iret
876 .previous
877 #endif
879 .section .fixup,"ax"
880 bad_iret:
881 /*
882 * The iret traps when the %cs or %ss being restored is bogus.
883 * We've lost the original trap vector and error code.
884 * #GPF is the most likely one to get for an invalid selector.
885 * So pretend we completed the iret and took the #GPF in user mode.
886 *
887 * We are now running with the kernel GS after exception recovery.
888 * But error_entry expects us to have user GS to match the user %cs,
889 * so swap back.
890 */
891 pushq $0
893 SWAPGS
894 jmp general_protection
896 .previous
898 /* edi: workmask, edx: work */
899 retint_careful:
900 CFI_RESTORE_STATE
901 bt $TIF_NEED_RESCHED,%edx
902 jnc retint_signal
903 TRACE_IRQS_ON
904 ENABLE_INTERRUPTS(CLBR_NONE)
905 pushq_cfi %rdi
906 call schedule
907 popq_cfi %rdi
908 GET_THREAD_INFO(%rcx)
909 DISABLE_INTERRUPTS(CLBR_NONE)
910 TRACE_IRQS_OFF
911 jmp retint_check
913 retint_signal:
914 testl $_TIF_DO_NOTIFY_MASK,%edx
915 jz retint_swapgs
916 TRACE_IRQS_ON
917 ENABLE_INTERRUPTS(CLBR_NONE)
918 SAVE_REST
919 movq $-1,ORIG_RAX(%rsp)
920 xorl %esi,%esi # oldset
921 movq %rsp,%rdi # &pt_regs
922 call do_notify_resume
923 RESTORE_REST
924 DISABLE_INTERRUPTS(CLBR_NONE)
925 TRACE_IRQS_OFF
926 GET_THREAD_INFO(%rcx)
927 jmp retint_with_reschedule
929 #ifdef CONFIG_PREEMPT
930 /* Returning to kernel space. Check if we need preemption */
931 /* rcx: threadinfo. interrupts off. */
932 ENTRY(retint_kernel)
933 cmpl $0,TI_preempt_count(%rcx)
934 jnz retint_restore_args
935 bt $TIF_NEED_RESCHED,TI_flags(%rcx)
936 jnc retint_restore_args
937 bt $9,EFLAGS-ARGOFFSET(%rsp) /* interrupts off? */
938 jnc retint_restore_args
939 call preempt_schedule_irq
940 jmp exit_intr
941 #endif
943 CFI_ENDPROC
944 END(common_interrupt)
945 /*
946 * End of kprobes section
947 */
948 .popsection
950 /*
951 * APIC interrupts.
952 */
953 .macro apicinterrupt num sym do_sym
954 ENTRY(\sym)
955 INTR_FRAME
956 pushq_cfi $~(\num)
957 interrupt \do_sym
958 jmp ret_from_intr
959 CFI_ENDPROC
960 END(\sym)
961 .endm
963 #ifdef CONFIG_SMP
964 apicinterrupt IRQ_MOVE_CLEANUP_VECTOR \
965 irq_move_cleanup_interrupt smp_irq_move_cleanup_interrupt
966 apicinterrupt REBOOT_VECTOR \
967 reboot_interrupt smp_reboot_interrupt
968 #endif
970 #ifdef CONFIG_X86_UV
971 apicinterrupt UV_BAU_MESSAGE \
972 uv_bau_message_intr1 uv_bau_message_interrupt
973 #endif
974 apicinterrupt LOCAL_TIMER_VECTOR \
975 apic_timer_interrupt smp_apic_timer_interrupt
976 apicinterrupt X86_PLATFORM_IPI_VECTOR \
977 x86_platform_ipi smp_x86_platform_ipi
979 #ifdef CONFIG_SMP
980 .irp idx,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15, \
981 16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31
982 .if NUM_INVALIDATE_TLB_VECTORS > \idx
983 apicinterrupt (INVALIDATE_TLB_VECTOR_START)+\idx \
984 invalidate_interrupt\idx smp_invalidate_interrupt
985 .endif
986 .endr
987 #endif
989 apicinterrupt THRESHOLD_APIC_VECTOR \
990 threshold_interrupt smp_threshold_interrupt
991 apicinterrupt THERMAL_APIC_VECTOR \
992 thermal_interrupt smp_thermal_interrupt
994 #ifdef CONFIG_X86_MCE
995 apicinterrupt MCE_SELF_VECTOR \
996 mce_self_interrupt smp_mce_self_interrupt
997 #endif
999 #ifdef CONFIG_SMP
1000 apicinterrupt CALL_FUNCTION_SINGLE_VECTOR \
1001 call_function_single_interrupt smp_call_function_single_interrupt
1002 apicinterrupt CALL_FUNCTION_VECTOR \
1003 call_function_interrupt smp_call_function_interrupt
1004 apicinterrupt RESCHEDULE_VECTOR \
1005 reschedule_interrupt smp_reschedule_interrupt
1006 #endif
1008 apicinterrupt ERROR_APIC_VECTOR \
1009 error_interrupt smp_error_interrupt
1010 apicinterrupt SPURIOUS_APIC_VECTOR \
1011 spurious_interrupt smp_spurious_interrupt
1013 #ifdef CONFIG_IRQ_WORK
1014 apicinterrupt IRQ_WORK_VECTOR \
1015 irq_work_interrupt smp_irq_work_interrupt
1016 #endif
1018 /*
1019 * Exception entry points.
1020 */
1021 .macro zeroentry sym do_sym
1022 ENTRY(\sym)
1023 INTR_FRAME
1024 PARAVIRT_ADJUST_EXCEPTION_FRAME
1025 pushq_cfi $-1 /* ORIG_RAX: no syscall to restart */
1026 subq $ORIG_RAX-R15, %rsp
1027 CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15
1028 call error_entry
1029 DEFAULT_FRAME 0
1030 movq %rsp,%rdi /* pt_regs pointer */
1031 xorl %esi,%esi /* no error code */
1032 call \do_sym
1033 jmp error_exit /* %ebx: no swapgs flag */
1034 CFI_ENDPROC
1035 END(\sym)
1036 .endm
1038 .macro paranoidzeroentry sym do_sym
1039 ENTRY(\sym)
1040 INTR_FRAME
1041 PARAVIRT_ADJUST_EXCEPTION_FRAME
1042 pushq_cfi $-1 /* ORIG_RAX: no syscall to restart */
1043 subq $ORIG_RAX-R15, %rsp
1044 CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15
1045 call save_paranoid
1046 TRACE_IRQS_OFF
1047 movq %rsp,%rdi /* pt_regs pointer */
1048 xorl %esi,%esi /* no error code */
1049 call \do_sym
1050 jmp paranoid_exit /* %ebx: no swapgs flag */
1051 CFI_ENDPROC
1052 END(\sym)
1053 .endm
1055 #define INIT_TSS_IST(x) PER_CPU_VAR(init_tss) + (TSS_ist + ((x) - 1) * 8)
1056 .macro paranoidzeroentry_ist sym do_sym ist
1057 ENTRY(\sym)
1058 INTR_FRAME
1059 PARAVIRT_ADJUST_EXCEPTION_FRAME
1060 pushq_cfi $-1 /* ORIG_RAX: no syscall to restart */
1061 subq $ORIG_RAX-R15, %rsp
1062 CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15
1063 call save_paranoid
1064 TRACE_IRQS_OFF
1065 movq %rsp,%rdi /* pt_regs pointer */
1066 xorl %esi,%esi /* no error code */
1067 subq $EXCEPTION_STKSZ, INIT_TSS_IST(\ist)
1068 call \do_sym
1069 addq $EXCEPTION_STKSZ, INIT_TSS_IST(\ist)
1070 jmp paranoid_exit /* %ebx: no swapgs flag */
1071 CFI_ENDPROC
1072 END(\sym)
1073 .endm
1075 .macro errorentry sym do_sym
1076 ENTRY(\sym)
1077 XCPT_FRAME
1078 PARAVIRT_ADJUST_EXCEPTION_FRAME
1079 subq $ORIG_RAX-R15, %rsp
1080 CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15
1081 call error_entry
1082 DEFAULT_FRAME 0
1083 movq %rsp,%rdi /* pt_regs pointer */
1084 movq ORIG_RAX(%rsp),%rsi /* get error code */
1085 movq $-1,ORIG_RAX(%rsp) /* no syscall to restart */
1086 call \do_sym
1087 jmp error_exit /* %ebx: no swapgs flag */
1088 CFI_ENDPROC
1089 END(\sym)
1090 .endm
1092 /* error code is on the stack already */
1093 .macro paranoiderrorentry sym do_sym
1094 ENTRY(\sym)
1095 XCPT_FRAME
1096 PARAVIRT_ADJUST_EXCEPTION_FRAME
1097 subq $ORIG_RAX-R15, %rsp
1098 CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15
1099 call save_paranoid
1100 DEFAULT_FRAME 0
1101 TRACE_IRQS_OFF
1102 movq %rsp,%rdi /* pt_regs pointer */
1103 movq ORIG_RAX(%rsp),%rsi /* get error code */
1104 movq $-1,ORIG_RAX(%rsp) /* no syscall to restart */
1105 call \do_sym
1106 jmp paranoid_exit /* %ebx: no swapgs flag */
1107 CFI_ENDPROC
1108 END(\sym)
1109 .endm
1111 zeroentry divide_error do_divide_error
1112 zeroentry overflow do_overflow
1113 zeroentry bounds do_bounds
1114 zeroentry invalid_op do_invalid_op
1115 zeroentry device_not_available do_device_not_available
1116 paranoiderrorentry double_fault do_double_fault
1117 zeroentry coprocessor_segment_overrun do_coprocessor_segment_overrun
1118 errorentry invalid_TSS do_invalid_TSS
1119 errorentry segment_not_present do_segment_not_present
1120 zeroentry spurious_interrupt_bug do_spurious_interrupt_bug
1121 zeroentry coprocessor_error do_coprocessor_error
1122 errorentry alignment_check do_alignment_check
1123 zeroentry simd_coprocessor_error do_simd_coprocessor_error
1125 /* Reload gs selector with exception handling */
1126 /* edi: new selector */
1127 ENTRY(native_load_gs_index)
1128 CFI_STARTPROC
1129 pushfq_cfi
1130 DISABLE_INTERRUPTS(CLBR_ANY & ~CLBR_RDI)
1131 SWAPGS
1132 gs_change:
1133 movl %edi,%gs
1134 2: mfence /* workaround */
1135 SWAPGS
1136 popfq_cfi
1137 ret
1138 CFI_ENDPROC
1139 END(native_load_gs_index)
1141 .section __ex_table,"a"
1142 .align 8
1143 .quad gs_change,bad_gs
1144 .previous
1145 .section .fixup,"ax"
1146 /* running with kernelgs */
1147 bad_gs:
1148 SWAPGS /* switch back to user gs */
1149 xorl %eax,%eax
1150 movl %eax,%gs
1151 jmp 2b
1152 .previous
1154 ENTRY(kernel_thread_helper)
1155 pushq $0 # fake return address
1156 CFI_STARTPROC
1157 /*
1158 * Here we are in the child and the registers are set as they were
1159 * at kernel_thread() invocation in the parent.
1160 */
1161 call *%rsi
1162 # exit
1163 mov %eax, %edi
1164 call do_exit
1165 ud2 # padding for call trace
1166 CFI_ENDPROC
1167 END(kernel_thread_helper)
1169 /*
1170 * execve(). This function needs to use IRET, not SYSRET, to set up all state properly.
1171 *
1172 * C extern interface:
1173 * extern long execve(const char *name, char **argv, char **envp)
1174 *
1175 * asm input arguments:
1176 * rdi: name, rsi: argv, rdx: envp
1177 *
1178 * We want to fallback into:
1179 * extern long sys_execve(const char *name, char **argv,char **envp, struct pt_regs *regs)
1180 *
1181 * do_sys_execve asm fallback arguments:
1182 * rdi: name, rsi: argv, rdx: envp, rcx: fake frame on the stack
1183 */
1184 ENTRY(kernel_execve)
1185 CFI_STARTPROC
1186 FAKE_STACK_FRAME $0
1187 SAVE_ALL
1188 movq %rsp,%rcx
1189 call sys_execve
1190 movq %rax, RAX(%rsp)
1191 RESTORE_REST
1192 testq %rax,%rax
1193 je int_ret_from_sys_call
1194 RESTORE_ARGS
1195 UNFAKE_STACK_FRAME
1196 ret
1197 CFI_ENDPROC
1198 END(kernel_execve)
1200 /* Call softirq on interrupt stack. Interrupts are off. */
1201 ENTRY(call_softirq)
1202 CFI_STARTPROC
1203 pushq_cfi %rbp
1204 CFI_REL_OFFSET rbp,0
1205 mov %rsp,%rbp
1206 CFI_DEF_CFA_REGISTER rbp
1207 incl PER_CPU_VAR(irq_count)
1208 cmove PER_CPU_VAR(irq_stack_ptr),%rsp
1209 push %rbp # backlink for old unwinder
1210 call __do_softirq
1211 leaveq
1212 CFI_RESTORE rbp
1213 CFI_DEF_CFA_REGISTER rsp
1214 CFI_ADJUST_CFA_OFFSET -8
1215 decl PER_CPU_VAR(irq_count)
1216 ret
1217 CFI_ENDPROC
1218 END(call_softirq)
1220 #ifdef CONFIG_XEN
1221 zeroentry xen_hypervisor_callback xen_do_hypervisor_callback
1223 /*
1224 * A note on the "critical region" in our callback handler.
1225 * We want to avoid stacking callback handlers due to events occurring
1226 * during handling of the last event. To do this, we keep events disabled
1227 * until we've done all processing. HOWEVER, we must enable events before
1228 * popping the stack frame (can't be done atomically) and so it would still
1229 * be possible to get enough handler activations to overflow the stack.
1230 * Although unlikely, bugs of that kind are hard to track down, so we'd
1231 * like to avoid the possibility.
1232 * So, on entry to the handler we detect whether we interrupted an
1233 * existing activation in its critical region -- if so, we pop the current
1234 * activation and restart the handler using the previous one.
1235 */
1236 ENTRY(xen_do_hypervisor_callback) # do_hypervisor_callback(struct *pt_regs)
1237 CFI_STARTPROC
1238 /*
1239 * Since we don't modify %rdi, evtchn_do_upall(struct *pt_regs) will
1240 * see the correct pointer to the pt_regs
1241 */
1242 movq %rdi, %rsp # we don't return, adjust the stack frame
1243 CFI_ENDPROC
1244 DEFAULT_FRAME
1245 11: incl PER_CPU_VAR(irq_count)
1246 movq %rsp,%rbp
1247 CFI_DEF_CFA_REGISTER rbp
1248 cmovzq PER_CPU_VAR(irq_stack_ptr),%rsp
1249 pushq %rbp # backlink for old unwinder
1250 call xen_evtchn_do_upcall
1251 popq %rsp
1252 CFI_DEF_CFA_REGISTER rsp
1253 decl PER_CPU_VAR(irq_count)
1254 jmp error_exit
1255 CFI_ENDPROC
1256 END(xen_do_hypervisor_callback)
1258 /*
1259 * Hypervisor uses this for application faults while it executes.
1260 * We get here for two reasons:
1261 * 1. Fault while reloading DS, ES, FS or GS
1262 * 2. Fault while executing IRET
1263 * Category 1 we do not need to fix up as Xen has already reloaded all segment
1264 * registers that could be reloaded and zeroed the others.
1265 * Category 2 we fix up by killing the current process. We cannot use the
1266 * normal Linux return path in this case because if we use the IRET hypercall
1267 * to pop the stack frame we end up in an infinite loop of failsafe callbacks.
1268 * We distinguish between categories by comparing each saved segment register
1269 * with its current contents: any discrepancy means we in category 1.
1270 */
1271 ENTRY(xen_failsafe_callback)
1272 INTR_FRAME 1 (6*8)
1273 /*CFI_REL_OFFSET gs,GS*/
1274 /*CFI_REL_OFFSET fs,FS*/
1275 /*CFI_REL_OFFSET es,ES*/
1276 /*CFI_REL_OFFSET ds,DS*/
1277 CFI_REL_OFFSET r11,8
1278 CFI_REL_OFFSET rcx,0
1279 movw %ds,%cx
1280 cmpw %cx,0x10(%rsp)
1281 CFI_REMEMBER_STATE
1282 jne 1f
1283 movw %es,%cx
1284 cmpw %cx,0x18(%rsp)
1285 jne 1f
1286 movw %fs,%cx
1287 cmpw %cx,0x20(%rsp)
1288 jne 1f
1289 movw %gs,%cx
1290 cmpw %cx,0x28(%rsp)
1291 jne 1f
1292 /* All segments match their saved values => Category 2 (Bad IRET). */
1293 movq (%rsp),%rcx
1294 CFI_RESTORE rcx
1295 movq 8(%rsp),%r11
1296 CFI_RESTORE r11
1297 addq $0x30,%rsp
1298 CFI_ADJUST_CFA_OFFSET -0x30
1299 pushq_cfi $0 /* RIP */
1300 pushq_cfi %r11
1301 pushq_cfi %rcx
1302 jmp general_protection
1303 CFI_RESTORE_STATE
1304 1: /* Segment mismatch => Category 1 (Bad segment). Retry the IRET. */
1305 movq (%rsp),%rcx
1306 CFI_RESTORE rcx
1307 movq 8(%rsp),%r11
1308 CFI_RESTORE r11
1309 addq $0x30,%rsp
1310 CFI_ADJUST_CFA_OFFSET -0x30
1311 pushq_cfi $0
1312 SAVE_ALL
1313 jmp error_exit
1314 CFI_ENDPROC
1315 END(xen_failsafe_callback)
1317 apicinterrupt XEN_HVM_EVTCHN_CALLBACK \
1318 xen_hvm_callback_vector xen_evtchn_do_upcall
1320 #endif /* CONFIG_XEN */
1322 /*
1323 * Some functions should be protected against kprobes
1324 */
1325 .pushsection .kprobes.text, "ax"
1327 paranoidzeroentry_ist debug do_debug DEBUG_STACK
1328 paranoidzeroentry_ist int3 do_int3 DEBUG_STACK
1329 paranoiderrorentry stack_segment do_stack_segment
1330 #ifdef CONFIG_XEN
1331 zeroentry xen_debug do_debug
1332 zeroentry xen_int3 do_int3
1333 errorentry xen_stack_segment do_stack_segment
1334 #endif
1335 errorentry general_protection do_general_protection
1336 errorentry page_fault do_page_fault
1337 #ifdef CONFIG_KVM_GUEST
1338 errorentry async_page_fault do_async_page_fault
1339 #endif
1340 #ifdef CONFIG_X86_MCE
1341 paranoidzeroentry machine_check *machine_check_vector(%rip)
1342 #endif
1344 /*
1345 * "Paranoid" exit path from exception stack.
1346 * Paranoid because this is used by NMIs and cannot take
1347 * any kernel state for granted.
1348 * We don't do kernel preemption checks here, because only
1349 * NMI should be common and it does not enable IRQs and
1350 * cannot get reschedule ticks.
1351 *
1352 * "trace" is 0 for the NMI handler only, because irq-tracing
1353 * is fundamentally NMI-unsafe. (we cannot change the soft and
1354 * hard flags at once, atomically)
1355 */
1357 /* ebx: no swapgs flag */
1358 ENTRY(paranoid_exit)
1359 DEFAULT_FRAME
1360 DISABLE_INTERRUPTS(CLBR_NONE)
1361 TRACE_IRQS_OFF
1362 testl %ebx,%ebx /* swapgs needed? */
1363 jnz paranoid_restore
1364 testl $3,CS(%rsp)
1365 jnz paranoid_userspace
1366 paranoid_swapgs:
1367 TRACE_IRQS_IRETQ 0
1368 SWAPGS_UNSAFE_STACK
1369 RESTORE_ALL 8
1370 jmp irq_return
1371 paranoid_restore:
1372 TRACE_IRQS_IRETQ 0
1373 RESTORE_ALL 8
1374 jmp irq_return
1375 paranoid_userspace:
1376 GET_THREAD_INFO(%rcx)
1377 movl TI_flags(%rcx),%ebx
1378 andl $_TIF_WORK_MASK,%ebx
1379 jz paranoid_swapgs
1380 movq %rsp,%rdi /* &pt_regs */
1381 call sync_regs
1382 movq %rax,%rsp /* switch stack for scheduling */
1383 testl $_TIF_NEED_RESCHED,%ebx
1384 jnz paranoid_schedule
1385 movl %ebx,%edx /* arg3: thread flags */
1386 TRACE_IRQS_ON
1387 ENABLE_INTERRUPTS(CLBR_NONE)
1388 xorl %esi,%esi /* arg2: oldset */
1389 movq %rsp,%rdi /* arg1: &pt_regs */
1390 call do_notify_resume
1391 DISABLE_INTERRUPTS(CLBR_NONE)
1392 TRACE_IRQS_OFF
1393 jmp paranoid_userspace
1394 paranoid_schedule:
1395 TRACE_IRQS_ON
1396 ENABLE_INTERRUPTS(CLBR_ANY)
1397 call schedule
1398 DISABLE_INTERRUPTS(CLBR_ANY)
1399 TRACE_IRQS_OFF
1400 jmp paranoid_userspace
1401 CFI_ENDPROC
1402 END(paranoid_exit)
1404 /*
1405 * Exception entry point. This expects an error code/orig_rax on the stack.
1406 * returns in "no swapgs flag" in %ebx.
1407 */
1408 ENTRY(error_entry)
1409 XCPT_FRAME
1410 CFI_ADJUST_CFA_OFFSET 15*8
1411 /* oldrax contains error code */
1412 cld
1413 movq_cfi rdi, RDI+8
1414 movq_cfi rsi, RSI+8
1415 movq_cfi rdx, RDX+8
1416 movq_cfi rcx, RCX+8
1417 movq_cfi rax, RAX+8
1418 movq_cfi r8, R8+8
1419 movq_cfi r9, R9+8
1420 movq_cfi r10, R10+8
1421 movq_cfi r11, R11+8
1422 movq_cfi rbx, RBX+8
1423 movq_cfi rbp, RBP+8
1424 movq_cfi r12, R12+8
1425 movq_cfi r13, R13+8
1426 movq_cfi r14, R14+8
1427 movq_cfi r15, R15+8
1428 xorl %ebx,%ebx
1429 testl $3,CS+8(%rsp)
1430 je error_kernelspace
1431 error_swapgs:
1432 SWAPGS
1433 error_sti:
1434 TRACE_IRQS_OFF
1435 ret
1437 /*
1438 * There are two places in the kernel that can potentially fault with
1439 * usergs. Handle them here. The exception handlers after iret run with
1440 * kernel gs again, so don't set the user space flag. B stepping K8s
1441 * sometimes report an truncated RIP for IRET exceptions returning to
1442 * compat mode. Check for these here too.
1443 */
1444 error_kernelspace:
1445 incl %ebx
1446 leaq irq_return(%rip),%rcx
1447 cmpq %rcx,RIP+8(%rsp)
1448 je error_swapgs
1449 movl %ecx,%eax /* zero extend */
1450 cmpq %rax,RIP+8(%rsp)
1451 je bstep_iret
1452 cmpq $gs_change,RIP+8(%rsp)
1453 je error_swapgs
1454 jmp error_sti
1456 bstep_iret:
1457 /* Fix truncated RIP */
1458 movq %rcx,RIP+8(%rsp)
1459 jmp error_swapgs
1460 CFI_ENDPROC
1461 END(error_entry)
1464 /* ebx: no swapgs flag (1: don't need swapgs, 0: need it) */
1465 ENTRY(error_exit)
1466 DEFAULT_FRAME
1467 movl %ebx,%eax
1468 RESTORE_REST
1469 DISABLE_INTERRUPTS(CLBR_NONE)
1470 TRACE_IRQS_OFF
1471 GET_THREAD_INFO(%rcx)
1472 testl %eax,%eax
1473 jne retint_kernel
1474 LOCKDEP_SYS_EXIT_IRQ
1475 movl TI_flags(%rcx),%edx
1476 movl $_TIF_WORK_MASK,%edi
1477 andl %edi,%edx
1478 jnz retint_careful
1479 jmp retint_swapgs
1480 CFI_ENDPROC
1481 END(error_exit)
1484 /* runs on exception stack */
1485 ENTRY(nmi)
1486 INTR_FRAME
1487 PARAVIRT_ADJUST_EXCEPTION_FRAME
1488 pushq_cfi $-1
1489 subq $ORIG_RAX-R15, %rsp
1490 CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15
1491 call save_paranoid
1492 DEFAULT_FRAME 0
1493 /* paranoidentry do_nmi, 0; without TRACE_IRQS_OFF */
1494 movq %rsp,%rdi
1495 movq $-1,%rsi
1496 call do_nmi
1497 #ifdef CONFIG_TRACE_IRQFLAGS
1498 /* paranoidexit; without TRACE_IRQS_OFF */
1499 /* ebx: no swapgs flag */
1500 DISABLE_INTERRUPTS(CLBR_NONE)
1501 testl %ebx,%ebx /* swapgs needed? */
1502 jnz nmi_restore
1503 testl $3,CS(%rsp)
1504 jnz nmi_userspace
1505 nmi_swapgs:
1506 SWAPGS_UNSAFE_STACK
1507 nmi_restore:
1508 RESTORE_ALL 8
1509 jmp irq_return
1510 nmi_userspace:
1511 GET_THREAD_INFO(%rcx)
1512 movl TI_flags(%rcx),%ebx
1513 andl $_TIF_WORK_MASK,%ebx
1514 jz nmi_swapgs
1515 movq %rsp,%rdi /* &pt_regs */
1516 call sync_regs
1517 movq %rax,%rsp /* switch stack for scheduling */
1518 testl $_TIF_NEED_RESCHED,%ebx
1519 jnz nmi_schedule
1520 movl %ebx,%edx /* arg3: thread flags */
1521 ENABLE_INTERRUPTS(CLBR_NONE)
1522 xorl %esi,%esi /* arg2: oldset */
1523 movq %rsp,%rdi /* arg1: &pt_regs */
1524 call do_notify_resume
1525 DISABLE_INTERRUPTS(CLBR_NONE)
1526 jmp nmi_userspace
1527 nmi_schedule:
1528 ENABLE_INTERRUPTS(CLBR_ANY)
1529 call schedule
1530 DISABLE_INTERRUPTS(CLBR_ANY)
1531 jmp nmi_userspace
1532 CFI_ENDPROC
1533 #else
1534 jmp paranoid_exit
1535 CFI_ENDPROC
1536 #endif
1537 END(nmi)
1539 ENTRY(ignore_sysret)
1540 CFI_STARTPROC
1541 mov $-ENOSYS,%eax
1542 sysret
1543 CFI_ENDPROC
1544 END(ignore_sysret)
1546 /*
1547 * End of kprobes section
1548 */
1549 .popsection