| blob | faf8d5e74b0be311198f74dabd88293587d06025 |
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 * Some of this is documented in Documentation/x86/entry_64.txt
13 *
14 * NOTE: This code handles signal-recognition, which happens every time
15 * after an interrupt and after each system call.
16 *
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.
19 *
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 up to R11.
24 * - full stack frame: Like partial stack frame, but all register saved.
25 *
26 * Some macro usage:
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.
40 */
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>
49 #include <asm/msr.h>
50 #include <asm/unistd.h>
51 #include <asm/thread_info.h>
52 #include <asm/hw_irq.h>
53 #include <asm/page_types.h>
54 #include <asm/irqflags.h>
55 #include <asm/paravirt.h>
56 #include <asm/ftrace.h>
57 #include <asm/percpu.h>
59 /* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */
60 #include <linux/elf-em.h>
61 #define AUDIT_ARCH_X86_64 (EM_X86_64|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE)
62 #define __AUDIT_ARCH_64BIT 0x80000000
63 #define __AUDIT_ARCH_LE 0x40000000
65 .code64
66 .section .entry.text, "ax"
68 #ifdef CONFIG_FUNCTION_TRACER
69 #ifdef CONFIG_DYNAMIC_FTRACE
70 ENTRY(mcount)
71 retq
72 END(mcount)
74 ENTRY(ftrace_caller)
75 cmpl $0, function_trace_stop
76 jne ftrace_stub
78 MCOUNT_SAVE_FRAME
80 movq 0x38(%rsp), %rdi
81 movq 8(%rbp), %rsi
82 subq $MCOUNT_INSN_SIZE, %rdi
84 GLOBAL(ftrace_call)
85 call ftrace_stub
87 MCOUNT_RESTORE_FRAME
89 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
90 GLOBAL(ftrace_graph_call)
91 jmp ftrace_stub
92 #endif
94 GLOBAL(ftrace_stub)
95 retq
96 END(ftrace_caller)
98 #else /* ! CONFIG_DYNAMIC_FTRACE */
99 ENTRY(mcount)
100 cmpl $0, function_trace_stop
101 jne ftrace_stub
103 cmpq $ftrace_stub, ftrace_trace_function
104 jnz trace
106 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
107 cmpq $ftrace_stub, ftrace_graph_return
108 jnz ftrace_graph_caller
110 cmpq $ftrace_graph_entry_stub, ftrace_graph_entry
111 jnz ftrace_graph_caller
112 #endif
114 GLOBAL(ftrace_stub)
115 retq
117 trace:
118 MCOUNT_SAVE_FRAME
120 movq 0x38(%rsp), %rdi
121 movq 8(%rbp), %rsi
122 subq $MCOUNT_INSN_SIZE, %rdi
124 call *ftrace_trace_function
126 MCOUNT_RESTORE_FRAME
128 jmp ftrace_stub
129 END(mcount)
130 #endif /* CONFIG_DYNAMIC_FTRACE */
131 #endif /* CONFIG_FUNCTION_TRACER */
133 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
134 ENTRY(ftrace_graph_caller)
135 cmpl $0, function_trace_stop
136 jne ftrace_stub
138 MCOUNT_SAVE_FRAME
140 leaq 8(%rbp), %rdi
141 movq 0x38(%rsp), %rsi
142 movq (%rbp), %rdx
143 subq $MCOUNT_INSN_SIZE, %rsi
145 call prepare_ftrace_return
147 MCOUNT_RESTORE_FRAME
149 retq
150 END(ftrace_graph_caller)
152 GLOBAL(return_to_handler)
153 subq $24, %rsp
155 /* Save the return values */
156 movq %rax, (%rsp)
157 movq %rdx, 8(%rsp)
158 movq %rbp, %rdi
160 call ftrace_return_to_handler
162 movq %rax, %rdi
163 movq 8(%rsp), %rdx
164 movq (%rsp), %rax
165 addq $24, %rsp
166 jmp *%rdi
167 #endif
170 #ifndef CONFIG_PREEMPT
171 #define retint_kernel retint_restore_args
172 #endif
174 #ifdef CONFIG_PARAVIRT
175 ENTRY(native_usergs_sysret64)
176 swapgs
177 sysretq
178 ENDPROC(native_usergs_sysret64)
179 #endif /* CONFIG_PARAVIRT */
182 .macro TRACE_IRQS_IRETQ offset=ARGOFFSET
183 #ifdef CONFIG_TRACE_IRQFLAGS
184 bt $9,EFLAGS-\offset(%rsp) /* interrupts off? */
185 jnc 1f
186 TRACE_IRQS_ON
187 1:
188 #endif
189 .endm
191 /*
192 * C code is not supposed to know about undefined top of stack. Every time
193 * a C function with an pt_regs argument is called from the SYSCALL based
194 * fast path FIXUP_TOP_OF_STACK is needed.
195 * RESTORE_TOP_OF_STACK syncs the syscall state after any possible ptregs
196 * manipulation.
197 */
199 /* %rsp:at FRAMEEND */
200 .macro FIXUP_TOP_OF_STACK tmp offset=0
201 movq PER_CPU_VAR(old_rsp),\tmp
202 movq \tmp,RSP+\offset(%rsp)
203 movq $__USER_DS,SS+\offset(%rsp)
204 movq $__USER_CS,CS+\offset(%rsp)
205 movq $-1,RCX+\offset(%rsp)
206 movq R11+\offset(%rsp),\tmp /* get eflags */
207 movq \tmp,EFLAGS+\offset(%rsp)
208 .endm
210 .macro RESTORE_TOP_OF_STACK tmp offset=0
211 movq RSP+\offset(%rsp),\tmp
212 movq \tmp,PER_CPU_VAR(old_rsp)
213 movq EFLAGS+\offset(%rsp),\tmp
214 movq \tmp,R11+\offset(%rsp)
215 .endm
217 .macro FAKE_STACK_FRAME child_rip
218 /* push in order ss, rsp, eflags, cs, rip */
219 xorl %eax, %eax
220 pushq_cfi $__KERNEL_DS /* ss */
221 /*CFI_REL_OFFSET ss,0*/
222 pushq_cfi %rax /* rsp */
223 CFI_REL_OFFSET rsp,0
224 pushq_cfi $X86_EFLAGS_IF /* eflags - interrupts on */
225 /*CFI_REL_OFFSET rflags,0*/
226 pushq_cfi $__KERNEL_CS /* cs */
227 /*CFI_REL_OFFSET cs,0*/
228 pushq_cfi \child_rip /* rip */
229 CFI_REL_OFFSET rip,0
230 pushq_cfi %rax /* orig rax */
231 .endm
233 .macro UNFAKE_STACK_FRAME
234 addq $8*6, %rsp
235 CFI_ADJUST_CFA_OFFSET -(6*8)
236 .endm
238 /*
239 * initial frame state for interrupts (and exceptions without error code)
240 */
241 .macro EMPTY_FRAME start=1 offset=0
242 .if \start
243 CFI_STARTPROC simple
244 CFI_SIGNAL_FRAME
245 CFI_DEF_CFA rsp,8+\offset
246 .else
247 CFI_DEF_CFA_OFFSET 8+\offset
248 .endif
249 .endm
251 /*
252 * initial frame state for interrupts (and exceptions without error code)
253 */
254 .macro INTR_FRAME start=1 offset=0
255 EMPTY_FRAME \start, SS+8+\offset-RIP
256 /*CFI_REL_OFFSET ss, SS+\offset-RIP*/
257 CFI_REL_OFFSET rsp, RSP+\offset-RIP
258 /*CFI_REL_OFFSET rflags, EFLAGS+\offset-RIP*/
259 /*CFI_REL_OFFSET cs, CS+\offset-RIP*/
260 CFI_REL_OFFSET rip, RIP+\offset-RIP
261 .endm
263 /*
264 * initial frame state for exceptions with error code (and interrupts
265 * with vector already pushed)
266 */
267 .macro XCPT_FRAME start=1 offset=0
268 INTR_FRAME \start, RIP+\offset-ORIG_RAX
269 /*CFI_REL_OFFSET orig_rax, ORIG_RAX-ORIG_RAX*/
270 .endm
272 /*
273 * frame that enables calling into C.
274 */
275 .macro PARTIAL_FRAME start=1 offset=0
276 XCPT_FRAME \start, ORIG_RAX+\offset-ARGOFFSET
277 CFI_REL_OFFSET rdi, RDI+\offset-ARGOFFSET
278 CFI_REL_OFFSET rsi, RSI+\offset-ARGOFFSET
279 CFI_REL_OFFSET rdx, RDX+\offset-ARGOFFSET
280 CFI_REL_OFFSET rcx, RCX+\offset-ARGOFFSET
281 CFI_REL_OFFSET rax, RAX+\offset-ARGOFFSET
282 CFI_REL_OFFSET r8, R8+\offset-ARGOFFSET
283 CFI_REL_OFFSET r9, R9+\offset-ARGOFFSET
284 CFI_REL_OFFSET r10, R10+\offset-ARGOFFSET
285 CFI_REL_OFFSET r11, R11+\offset-ARGOFFSET
286 .endm
288 /*
289 * frame that enables passing a complete pt_regs to a C function.
290 */
291 .macro DEFAULT_FRAME start=1 offset=0
292 PARTIAL_FRAME \start, R11+\offset-R15
293 CFI_REL_OFFSET rbx, RBX+\offset
294 CFI_REL_OFFSET rbp, RBP+\offset
295 CFI_REL_OFFSET r12, R12+\offset
296 CFI_REL_OFFSET r13, R13+\offset
297 CFI_REL_OFFSET r14, R14+\offset
298 CFI_REL_OFFSET r15, R15+\offset
299 .endm
301 /* save partial stack frame */
302 .macro SAVE_ARGS_IRQ
303 cld
304 /* start from rbp in pt_regs and jump over */
305 movq_cfi rdi, RDI-RBP
306 movq_cfi rsi, RSI-RBP
307 movq_cfi rdx, RDX-RBP
308 movq_cfi rcx, RCX-RBP
309 movq_cfi rax, RAX-RBP
310 movq_cfi r8, R8-RBP
311 movq_cfi r9, R9-RBP
312 movq_cfi r10, R10-RBP
313 movq_cfi r11, R11-RBP
315 /* Save rbp so that we can unwind from get_irq_regs() */
316 movq_cfi rbp, 0
318 /* Save previous stack value */
319 movq %rsp, %rsi
321 leaq -RBP(%rsp),%rdi /* arg1 for handler */
322 testl $3, CS(%rdi)
323 je 1f
324 SWAPGS
325 /*
326 * irq_count is used to check if a CPU is already on an interrupt stack
327 * or not. While this is essentially redundant with preempt_count it is
328 * a little cheaper to use a separate counter in the PDA (short of
329 * moving irq_enter into assembly, which would be too much work)
330 */
331 1: incl PER_CPU_VAR(irq_count)
332 jne 2f
333 mov PER_CPU_VAR(irq_stack_ptr),%rsp
334 CFI_DEF_CFA_REGISTER rsi
336 2: /* Store previous stack value */
337 pushq %rsi
338 CFI_ESCAPE 0x0f /* DW_CFA_def_cfa_expression */, 6, \
339 0x77 /* DW_OP_breg7 */, 0, \
340 0x06 /* DW_OP_deref */, \
341 0x08 /* DW_OP_const1u */, SS+8-RBP, \
342 0x22 /* DW_OP_plus */
343 /* We entered an interrupt context - irqs are off: */
344 TRACE_IRQS_OFF
345 .endm
347 ENTRY(save_rest)
348 PARTIAL_FRAME 1 REST_SKIP+8
349 movq 5*8+16(%rsp), %r11 /* save return address */
350 movq_cfi rbx, RBX+16
351 movq_cfi rbp, RBP+16
352 movq_cfi r12, R12+16
353 movq_cfi r13, R13+16
354 movq_cfi r14, R14+16
355 movq_cfi r15, R15+16
356 movq %r11, 8(%rsp) /* return address */
357 FIXUP_TOP_OF_STACK %r11, 16
358 ret
359 CFI_ENDPROC
360 END(save_rest)
362 /* save complete stack frame */
363 .pushsection .kprobes.text, "ax"
364 ENTRY(save_paranoid)
365 XCPT_FRAME 1 RDI+8
366 cld
367 movq_cfi rdi, RDI+8
368 movq_cfi rsi, RSI+8
369 movq_cfi rdx, RDX+8
370 movq_cfi rcx, RCX+8
371 movq_cfi rax, RAX+8
372 movq_cfi r8, R8+8
373 movq_cfi r9, R9+8
374 movq_cfi r10, R10+8
375 movq_cfi r11, R11+8
376 movq_cfi rbx, RBX+8
377 movq_cfi rbp, RBP+8
378 movq_cfi r12, R12+8
379 movq_cfi r13, R13+8
380 movq_cfi r14, R14+8
381 movq_cfi r15, R15+8
382 movl $1,%ebx
383 movl $MSR_GS_BASE,%ecx
384 rdmsr
385 testl %edx,%edx
386 js 1f /* negative -> in kernel */
387 SWAPGS
388 xorl %ebx,%ebx
389 1: ret
390 CFI_ENDPROC
391 END(save_paranoid)
392 .popsection
394 /*
395 * A newly forked process directly context switches into this address.
396 *
397 * rdi: prev task we switched from
398 */
399 ENTRY(ret_from_fork)
400 DEFAULT_FRAME
402 LOCK ; btr $TIF_FORK,TI_flags(%r8)
404 pushq_cfi kernel_eflags(%rip)
405 popfq_cfi # reset kernel eflags
407 call schedule_tail # rdi: 'prev' task parameter
409 GET_THREAD_INFO(%rcx)
411 RESTORE_REST
413 testl $3, CS-ARGOFFSET(%rsp) # from kernel_thread?
414 je int_ret_from_sys_call
416 testl $_TIF_IA32, TI_flags(%rcx) # 32-bit compat task needs IRET
417 jnz int_ret_from_sys_call
419 RESTORE_TOP_OF_STACK %rdi, -ARGOFFSET
420 jmp ret_from_sys_call # go to the SYSRET fastpath
422 CFI_ENDPROC
423 END(ret_from_fork)
425 /*
426 * System call entry. Up to 6 arguments in registers are supported.
427 *
428 * SYSCALL does not save anything on the stack and does not change the
429 * stack pointer.
430 */
432 /*
433 * Register setup:
434 * rax system call number
435 * rdi arg0
436 * rcx return address for syscall/sysret, C arg3
437 * rsi arg1
438 * rdx arg2
439 * r10 arg3 (--> moved to rcx for C)
440 * r8 arg4
441 * r9 arg5
442 * r11 eflags for syscall/sysret, temporary for C
443 * r12-r15,rbp,rbx saved by C code, not touched.
444 *
445 * Interrupts are off on entry.
446 * Only called from user space.
447 *
448 * XXX if we had a free scratch register we could save the RSP into the stack frame
449 * and report it properly in ps. Unfortunately we haven't.
450 *
451 * When user can change the frames always force IRET. That is because
452 * it deals with uncanonical addresses better. SYSRET has trouble
453 * with them due to bugs in both AMD and Intel CPUs.
454 */
456 ENTRY(system_call)
457 CFI_STARTPROC simple
458 CFI_SIGNAL_FRAME
459 CFI_DEF_CFA rsp,KERNEL_STACK_OFFSET
460 CFI_REGISTER rip,rcx
461 /*CFI_REGISTER rflags,r11*/
462 SWAPGS_UNSAFE_STACK
463 /*
464 * A hypervisor implementation might want to use a label
465 * after the swapgs, so that it can do the swapgs
466 * for the guest and jump here on syscall.
467 */
468 ENTRY(system_call_after_swapgs)
470 movq %rsp,PER_CPU_VAR(old_rsp)
471 movq PER_CPU_VAR(kernel_stack),%rsp
472 /*
473 * No need to follow this irqs off/on section - it's straight
474 * and short:
475 */
476 ENABLE_INTERRUPTS(CLBR_NONE)
477 SAVE_ARGS 8,0
478 movq %rax,ORIG_RAX-ARGOFFSET(%rsp)
479 movq %rcx,RIP-ARGOFFSET(%rsp)
480 CFI_REL_OFFSET rip,RIP-ARGOFFSET
481 GET_THREAD_INFO(%rcx)
482 testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%rcx)
483 jnz tracesys
484 system_call_fastpath:
485 cmpq $__NR_syscall_max,%rax
486 ja badsys
487 movq %r10,%rcx
488 call *sys_call_table(,%rax,8) # XXX: rip relative
489 movq %rax,RAX-ARGOFFSET(%rsp)
490 /*
491 * Syscall return path ending with SYSRET (fast path)
492 * Has incomplete stack frame and undefined top of stack.
493 */
494 ret_from_sys_call:
495 movl $_TIF_ALLWORK_MASK,%edi
496 /* edi: flagmask */
497 sysret_check:
498 LOCKDEP_SYS_EXIT
499 GET_THREAD_INFO(%rcx)
500 DISABLE_INTERRUPTS(CLBR_NONE)
501 TRACE_IRQS_OFF
502 movl TI_flags(%rcx),%edx
503 andl %edi,%edx
504 jnz sysret_careful
505 CFI_REMEMBER_STATE
506 /*
507 * sysretq will re-enable interrupts:
508 */
509 TRACE_IRQS_ON
510 movq RIP-ARGOFFSET(%rsp),%rcx
511 CFI_REGISTER rip,rcx
512 RESTORE_ARGS 1,-ARG_SKIP,0
513 /*CFI_REGISTER rflags,r11*/
514 movq PER_CPU_VAR(old_rsp), %rsp
515 USERGS_SYSRET64
517 CFI_RESTORE_STATE
518 /* Handle reschedules */
519 /* edx: work, edi: workmask */
520 sysret_careful:
521 bt $TIF_NEED_RESCHED,%edx
522 jnc sysret_signal
523 TRACE_IRQS_ON
524 ENABLE_INTERRUPTS(CLBR_NONE)
525 pushq_cfi %rdi
526 call schedule
527 popq_cfi %rdi
528 jmp sysret_check
530 /* Handle a signal */
531 sysret_signal:
532 TRACE_IRQS_ON
533 ENABLE_INTERRUPTS(CLBR_NONE)
534 #ifdef CONFIG_AUDITSYSCALL
535 bt $TIF_SYSCALL_AUDIT,%edx
536 jc sysret_audit
537 #endif
538 /*
539 * We have a signal, or exit tracing or single-step.
540 * These all wind up with the iret return path anyway,
541 * so just join that path right now.
542 */
543 FIXUP_TOP_OF_STACK %r11, -ARGOFFSET
544 jmp int_check_syscall_exit_work
546 badsys:
547 movq $-ENOSYS,RAX-ARGOFFSET(%rsp)
548 jmp ret_from_sys_call
550 #ifdef CONFIG_AUDITSYSCALL
551 /*
552 * Fast path for syscall audit without full syscall trace.
553 * We just call audit_syscall_entry() directly, and then
554 * jump back to the normal fast path.
555 */
556 auditsys:
557 movq %r10,%r9 /* 6th arg: 4th syscall arg */
558 movq %rdx,%r8 /* 5th arg: 3rd syscall arg */
559 movq %rsi,%rcx /* 4th arg: 2nd syscall arg */
560 movq %rdi,%rdx /* 3rd arg: 1st syscall arg */
561 movq %rax,%rsi /* 2nd arg: syscall number */
562 movl $AUDIT_ARCH_X86_64,%edi /* 1st arg: audit arch */
563 call audit_syscall_entry
564 LOAD_ARGS 0 /* reload call-clobbered registers */
565 jmp system_call_fastpath
567 /*
568 * Return fast path for syscall audit. Call audit_syscall_exit()
569 * directly and then jump back to the fast path with TIF_SYSCALL_AUDIT
570 * masked off.
571 */
572 sysret_audit:
573 movq RAX-ARGOFFSET(%rsp),%rsi /* second arg, syscall return value */
574 cmpq $0,%rsi /* is it < 0? */
575 setl %al /* 1 if so, 0 if not */
576 movzbl %al,%edi /* zero-extend that into %edi */
577 inc %edi /* first arg, 0->1(AUDITSC_SUCCESS), 1->2(AUDITSC_FAILURE) */
578 call audit_syscall_exit
579 movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),%edi
580 jmp sysret_check
581 #endif /* CONFIG_AUDITSYSCALL */
583 /* Do syscall tracing */
584 tracesys:
585 #ifdef CONFIG_AUDITSYSCALL
586 testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%rcx)
587 jz auditsys
588 #endif
589 SAVE_REST
590 movq $-ENOSYS,RAX(%rsp) /* ptrace can change this for a bad syscall */
591 FIXUP_TOP_OF_STACK %rdi
592 movq %rsp,%rdi
593 call syscall_trace_enter
594 /*
595 * Reload arg registers from stack in case ptrace changed them.
596 * We don't reload %rax because syscall_trace_enter() returned
597 * the value it wants us to use in the table lookup.
598 */
599 LOAD_ARGS ARGOFFSET, 1
600 RESTORE_REST
601 cmpq $__NR_syscall_max,%rax
602 ja int_ret_from_sys_call /* RAX(%rsp) set to -ENOSYS above */
603 movq %r10,%rcx /* fixup for C */
604 call *sys_call_table(,%rax,8)
605 movq %rax,RAX-ARGOFFSET(%rsp)
606 /* Use IRET because user could have changed frame */
608 /*
609 * Syscall return path ending with IRET.
610 * Has correct top of stack, but partial stack frame.
611 */
612 GLOBAL(int_ret_from_sys_call)
613 DISABLE_INTERRUPTS(CLBR_NONE)
614 TRACE_IRQS_OFF
615 testl $3,CS-ARGOFFSET(%rsp)
616 je retint_restore_args
617 movl $_TIF_ALLWORK_MASK,%edi
618 /* edi: mask to check */
619 GLOBAL(int_with_check)
620 LOCKDEP_SYS_EXIT_IRQ
621 GET_THREAD_INFO(%rcx)
622 movl TI_flags(%rcx),%edx
623 andl %edi,%edx
624 jnz int_careful
625 andl $~TS_COMPAT,TI_status(%rcx)
626 jmp retint_swapgs
628 /* Either reschedule or signal or syscall exit tracking needed. */
629 /* First do a reschedule test. */
630 /* edx: work, edi: workmask */
631 int_careful:
632 bt $TIF_NEED_RESCHED,%edx
633 jnc int_very_careful
634 TRACE_IRQS_ON
635 ENABLE_INTERRUPTS(CLBR_NONE)
636 pushq_cfi %rdi
637 call schedule
638 popq_cfi %rdi
639 DISABLE_INTERRUPTS(CLBR_NONE)
640 TRACE_IRQS_OFF
641 jmp int_with_check
643 /* handle signals and tracing -- both require a full stack frame */
644 int_very_careful:
645 TRACE_IRQS_ON
646 ENABLE_INTERRUPTS(CLBR_NONE)
647 int_check_syscall_exit_work:
648 SAVE_REST
649 /* Check for syscall exit trace */
650 testl $_TIF_WORK_SYSCALL_EXIT,%edx
651 jz int_signal
652 pushq_cfi %rdi
653 leaq 8(%rsp),%rdi # &ptregs -> arg1
654 call syscall_trace_leave
655 popq_cfi %rdi
656 andl $~(_TIF_WORK_SYSCALL_EXIT|_TIF_SYSCALL_EMU),%edi
657 jmp int_restore_rest
659 int_signal:
660 testl $_TIF_DO_NOTIFY_MASK,%edx
661 jz 1f
662 movq %rsp,%rdi # &ptregs -> arg1
663 xorl %esi,%esi # oldset -> arg2
664 call do_notify_resume
665 1: movl $_TIF_WORK_MASK,%edi
666 int_restore_rest:
667 RESTORE_REST
668 DISABLE_INTERRUPTS(CLBR_NONE)
669 TRACE_IRQS_OFF
670 jmp int_with_check
671 CFI_ENDPROC
672 END(system_call)
674 /*
675 * Certain special system calls that need to save a complete full stack frame.
676 */
677 .macro PTREGSCALL label,func,arg
678 ENTRY(\label)
679 PARTIAL_FRAME 1 8 /* offset 8: return address */
680 subq $REST_SKIP, %rsp
681 CFI_ADJUST_CFA_OFFSET REST_SKIP
682 call save_rest
683 DEFAULT_FRAME 0 8 /* offset 8: return address */
684 leaq 8(%rsp), \arg /* pt_regs pointer */
685 call \func
686 jmp ptregscall_common
687 CFI_ENDPROC
688 END(\label)
689 .endm
691 PTREGSCALL stub_clone, sys_clone, %r8
692 PTREGSCALL stub_fork, sys_fork, %rdi
693 PTREGSCALL stub_vfork, sys_vfork, %rdi
694 PTREGSCALL stub_sigaltstack, sys_sigaltstack, %rdx
695 PTREGSCALL stub_iopl, sys_iopl, %rsi
697 ENTRY(ptregscall_common)
698 DEFAULT_FRAME 1 8 /* offset 8: return address */
699 RESTORE_TOP_OF_STACK %r11, 8
700 movq_cfi_restore R15+8, r15
701 movq_cfi_restore R14+8, r14
702 movq_cfi_restore R13+8, r13
703 movq_cfi_restore R12+8, r12
704 movq_cfi_restore RBP+8, rbp
705 movq_cfi_restore RBX+8, rbx
706 ret $REST_SKIP /* pop extended registers */
707 CFI_ENDPROC
708 END(ptregscall_common)
710 ENTRY(stub_execve)
711 CFI_STARTPROC
712 addq $8, %rsp
713 PARTIAL_FRAME 0
714 SAVE_REST
715 FIXUP_TOP_OF_STACK %r11
716 movq %rsp, %rcx
717 call sys_execve
718 RESTORE_TOP_OF_STACK %r11
719 movq %rax,RAX(%rsp)
720 RESTORE_REST
721 jmp int_ret_from_sys_call
722 CFI_ENDPROC
723 END(stub_execve)
725 /*
726 * sigreturn is special because it needs to restore all registers on return.
727 * This cannot be done with SYSRET, so use the IRET return path instead.
728 */
729 ENTRY(stub_rt_sigreturn)
730 CFI_STARTPROC
731 addq $8, %rsp
732 PARTIAL_FRAME 0
733 SAVE_REST
734 movq %rsp,%rdi
735 FIXUP_TOP_OF_STACK %r11
736 call sys_rt_sigreturn
737 movq %rax,RAX(%rsp) # fixme, this could be done at the higher layer
738 RESTORE_REST
739 jmp int_ret_from_sys_call
740 CFI_ENDPROC
741 END(stub_rt_sigreturn)
743 /*
744 * Build the entry stubs and pointer table with some assembler magic.
745 * We pack 7 stubs into a single 32-byte chunk, which will fit in a
746 * single cache line on all modern x86 implementations.
747 */
748 .section .init.rodata,"a"
749 ENTRY(interrupt)
750 .section .entry.text
751 .p2align 5
752 .p2align CONFIG_X86_L1_CACHE_SHIFT
753 ENTRY(irq_entries_start)
754 INTR_FRAME
755 vector=FIRST_EXTERNAL_VECTOR
756 .rept (NR_VECTORS-FIRST_EXTERNAL_VECTOR+6)/7
757 .balign 32
758 .rept 7
759 .if vector < NR_VECTORS
760 .if vector <> FIRST_EXTERNAL_VECTOR
761 CFI_ADJUST_CFA_OFFSET -8
762 .endif
763 1: pushq_cfi $(~vector+0x80) /* Note: always in signed byte range */
764 .if ((vector-FIRST_EXTERNAL_VECTOR)%7) <> 6
765 jmp 2f
766 .endif
767 .previous
768 .quad 1b
769 .section .entry.text
770 vector=vector+1
771 .endif
772 .endr
773 2: jmp common_interrupt
774 .endr
775 CFI_ENDPROC
776 END(irq_entries_start)
778 .previous
779 END(interrupt)
780 .previous
782 /*
783 * Interrupt entry/exit.
784 *
785 * Interrupt entry points save only callee clobbered registers in fast path.
786 *
787 * Entry runs with interrupts off.
788 */
790 /* 0(%rsp): ~(interrupt number) */
791 .macro interrupt func
792 /* reserve pt_regs for scratch regs and rbp */
793 subq $ORIG_RAX-RBP, %rsp
794 CFI_ADJUST_CFA_OFFSET ORIG_RAX-RBP
795 SAVE_ARGS_IRQ
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)
818 /* Restore saved previous stack */
819 popq %rsi
820 CFI_DEF_CFA_REGISTER rsi
821 leaq ARGOFFSET-RBP(%rsi), %rsp
822 CFI_DEF_CFA_REGISTER rsp
823 CFI_ADJUST_CFA_OFFSET RBP-ARGOFFSET
825 exit_intr:
826 GET_THREAD_INFO(%rcx)
827 testl $3,CS-ARGOFFSET(%rsp)
828 je retint_kernel
830 /* Interrupt came from user space */
831 /*
832 * Has a correct top of stack, but a partial stack frame
833 * %rcx: thread info. Interrupts off.
834 */
835 retint_with_reschedule:
836 movl $_TIF_WORK_MASK,%edi
837 retint_check:
838 LOCKDEP_SYS_EXIT_IRQ
839 movl TI_flags(%rcx),%edx
840 andl %edi,%edx
841 CFI_REMEMBER_STATE
842 jnz retint_careful
844 retint_swapgs: /* return to user-space */
845 /*
846 * The iretq could re-enable interrupts:
847 */
848 DISABLE_INTERRUPTS(CLBR_ANY)
849 TRACE_IRQS_IRETQ
850 SWAPGS
851 jmp restore_args
853 retint_restore_args: /* return to kernel space */
854 DISABLE_INTERRUPTS(CLBR_ANY)
855 /*
856 * The iretq could re-enable interrupts:
857 */
858 TRACE_IRQS_IRETQ
859 restore_args:
860 RESTORE_ARGS 1,8,1
862 irq_return:
863 INTERRUPT_RETURN
865 .section __ex_table, "a"
866 .quad irq_return, bad_iret
867 .previous
869 #ifdef CONFIG_PARAVIRT
870 ENTRY(native_iret)
871 iretq
873 .section __ex_table,"a"
874 .quad native_iret, bad_iret
875 .previous
876 #endif
878 .section .fixup,"ax"
879 bad_iret:
880 /*
881 * The iret traps when the %cs or %ss being restored is bogus.
882 * We've lost the original trap vector and error code.
883 * #GPF is the most likely one to get for an invalid selector.
884 * So pretend we completed the iret and took the #GPF in user mode.
885 *
886 * We are now running with the kernel GS after exception recovery.
887 * But error_entry expects us to have user GS to match the user %cs,
888 * so swap back.
889 */
890 pushq $0
892 SWAPGS
893 jmp general_protection
895 .previous
897 /* edi: workmask, edx: work */
898 retint_careful:
899 CFI_RESTORE_STATE
900 bt $TIF_NEED_RESCHED,%edx
901 jnc retint_signal
902 TRACE_IRQS_ON
903 ENABLE_INTERRUPTS(CLBR_NONE)
904 pushq_cfi %rdi
905 call schedule
906 popq_cfi %rdi
907 GET_THREAD_INFO(%rcx)
908 DISABLE_INTERRUPTS(CLBR_NONE)
909 TRACE_IRQS_OFF
910 jmp retint_check
912 retint_signal:
913 testl $_TIF_DO_NOTIFY_MASK,%edx
914 jz retint_swapgs
915 TRACE_IRQS_ON
916 ENABLE_INTERRUPTS(CLBR_NONE)
917 SAVE_REST
918 movq $-1,ORIG_RAX(%rsp)
919 xorl %esi,%esi # oldset
920 movq %rsp,%rdi # &pt_regs
921 call do_notify_resume
922 RESTORE_REST
923 DISABLE_INTERRUPTS(CLBR_NONE)
924 TRACE_IRQS_OFF
925 GET_THREAD_INFO(%rcx)
926 jmp retint_with_reschedule
928 #ifdef CONFIG_PREEMPT
929 /* Returning to kernel space. Check if we need preemption */
930 /* rcx: threadinfo. interrupts off. */
931 ENTRY(retint_kernel)
932 cmpl $0,TI_preempt_count(%rcx)
933 jnz retint_restore_args
934 bt $TIF_NEED_RESCHED,TI_flags(%rcx)
935 jnc retint_restore_args
936 bt $9,EFLAGS-ARGOFFSET(%rsp) /* interrupts off? */
937 jnc retint_restore_args
938 call preempt_schedule_irq
939 jmp exit_intr
940 #endif
942 CFI_ENDPROC
943 END(common_interrupt)
944 /*
945 * End of kprobes section
946 */
947 .popsection
949 /*
950 * APIC interrupts.
951 */
952 .macro apicinterrupt num sym do_sym
953 ENTRY(\sym)
954 INTR_FRAME
955 pushq_cfi $~(\num)
956 interrupt \do_sym
957 jmp ret_from_intr
958 CFI_ENDPROC
959 END(\sym)
960 .endm
962 #ifdef CONFIG_SMP
963 apicinterrupt IRQ_MOVE_CLEANUP_VECTOR \
964 irq_move_cleanup_interrupt smp_irq_move_cleanup_interrupt
965 apicinterrupt REBOOT_VECTOR \
966 reboot_interrupt smp_reboot_interrupt
967 #endif
969 #ifdef CONFIG_X86_UV
970 apicinterrupt UV_BAU_MESSAGE \
971 uv_bau_message_intr1 uv_bau_message_interrupt
972 #endif
973 apicinterrupt LOCAL_TIMER_VECTOR \
974 apic_timer_interrupt smp_apic_timer_interrupt
975 apicinterrupt X86_PLATFORM_IPI_VECTOR \
976 x86_platform_ipi smp_x86_platform_ipi
978 #ifdef CONFIG_SMP
979 .irp idx,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15, \
980 16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31
981 .if NUM_INVALIDATE_TLB_VECTORS > \idx
982 apicinterrupt (INVALIDATE_TLB_VECTOR_START)+\idx \
983 invalidate_interrupt\idx smp_invalidate_interrupt
984 .endif
985 .endr
986 #endif
988 apicinterrupt THRESHOLD_APIC_VECTOR \
989 threshold_interrupt smp_threshold_interrupt
990 apicinterrupt THERMAL_APIC_VECTOR \
991 thermal_interrupt smp_thermal_interrupt
993 #ifdef CONFIG_SMP
994 apicinterrupt CALL_FUNCTION_SINGLE_VECTOR \
995 call_function_single_interrupt smp_call_function_single_interrupt
996 apicinterrupt CALL_FUNCTION_VECTOR \
997 call_function_interrupt smp_call_function_interrupt
998 apicinterrupt RESCHEDULE_VECTOR \
999 reschedule_interrupt smp_reschedule_interrupt
1000 #endif
1002 apicinterrupt ERROR_APIC_VECTOR \
1003 error_interrupt smp_error_interrupt
1004 apicinterrupt SPURIOUS_APIC_VECTOR \
1005 spurious_interrupt smp_spurious_interrupt
1007 #ifdef CONFIG_IRQ_WORK
1008 apicinterrupt IRQ_WORK_VECTOR \
1009 irq_work_interrupt smp_irq_work_interrupt
1010 #endif
1012 /*
1013 * Exception entry points.
1014 */
1015 .macro zeroentry sym do_sym
1016 ENTRY(\sym)
1017 INTR_FRAME
1018 PARAVIRT_ADJUST_EXCEPTION_FRAME
1019 pushq_cfi $-1 /* ORIG_RAX: no syscall to restart */
1020 subq $ORIG_RAX-R15, %rsp
1021 CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15
1022 call error_entry
1023 DEFAULT_FRAME 0
1024 movq %rsp,%rdi /* pt_regs pointer */
1025 xorl %esi,%esi /* no error code */
1026 call \do_sym
1027 jmp error_exit /* %ebx: no swapgs flag */
1028 CFI_ENDPROC
1029 END(\sym)
1030 .endm
1032 .macro paranoidzeroentry sym do_sym
1033 ENTRY(\sym)
1034 INTR_FRAME
1035 PARAVIRT_ADJUST_EXCEPTION_FRAME
1036 pushq_cfi $-1 /* ORIG_RAX: no syscall to restart */
1037 subq $ORIG_RAX-R15, %rsp
1038 CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15
1039 call save_paranoid
1040 TRACE_IRQS_OFF
1041 movq %rsp,%rdi /* pt_regs pointer */
1042 xorl %esi,%esi /* no error code */
1043 call \do_sym
1044 jmp paranoid_exit /* %ebx: no swapgs flag */
1045 CFI_ENDPROC
1046 END(\sym)
1047 .endm
1049 #define INIT_TSS_IST(x) PER_CPU_VAR(init_tss) + (TSS_ist + ((x) - 1) * 8)
1050 .macro paranoidzeroentry_ist sym do_sym ist
1051 ENTRY(\sym)
1052 INTR_FRAME
1053 PARAVIRT_ADJUST_EXCEPTION_FRAME
1054 pushq_cfi $-1 /* ORIG_RAX: no syscall to restart */
1055 subq $ORIG_RAX-R15, %rsp
1056 CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15
1057 call save_paranoid
1058 TRACE_IRQS_OFF
1059 movq %rsp,%rdi /* pt_regs pointer */
1060 xorl %esi,%esi /* no error code */
1061 subq $EXCEPTION_STKSZ, INIT_TSS_IST(\ist)
1062 call \do_sym
1063 addq $EXCEPTION_STKSZ, INIT_TSS_IST(\ist)
1064 jmp paranoid_exit /* %ebx: no swapgs flag */
1065 CFI_ENDPROC
1066 END(\sym)
1067 .endm
1069 .macro errorentry sym do_sym
1070 ENTRY(\sym)
1071 XCPT_FRAME
1072 PARAVIRT_ADJUST_EXCEPTION_FRAME
1073 subq $ORIG_RAX-R15, %rsp
1074 CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15
1075 call error_entry
1076 DEFAULT_FRAME 0
1077 movq %rsp,%rdi /* pt_regs pointer */
1078 movq ORIG_RAX(%rsp),%rsi /* get error code */
1079 movq $-1,ORIG_RAX(%rsp) /* no syscall to restart */
1080 call \do_sym
1081 jmp error_exit /* %ebx: no swapgs flag */
1082 CFI_ENDPROC
1083 END(\sym)
1084 .endm
1086 /* error code is on the stack already */
1087 .macro paranoiderrorentry sym do_sym
1088 ENTRY(\sym)
1089 XCPT_FRAME
1090 PARAVIRT_ADJUST_EXCEPTION_FRAME
1091 subq $ORIG_RAX-R15, %rsp
1092 CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15
1093 call save_paranoid
1094 DEFAULT_FRAME 0
1095 TRACE_IRQS_OFF
1096 movq %rsp,%rdi /* pt_regs pointer */
1097 movq ORIG_RAX(%rsp),%rsi /* get error code */
1098 movq $-1,ORIG_RAX(%rsp) /* no syscall to restart */
1099 call \do_sym
1100 jmp paranoid_exit /* %ebx: no swapgs flag */
1101 CFI_ENDPROC
1102 END(\sym)
1103 .endm
1105 zeroentry divide_error do_divide_error
1106 zeroentry overflow do_overflow
1107 zeroentry bounds do_bounds
1108 zeroentry invalid_op do_invalid_op
1109 zeroentry device_not_available do_device_not_available
1110 paranoiderrorentry double_fault do_double_fault
1111 zeroentry coprocessor_segment_overrun do_coprocessor_segment_overrun
1112 errorentry invalid_TSS do_invalid_TSS
1113 errorentry segment_not_present do_segment_not_present
1114 zeroentry spurious_interrupt_bug do_spurious_interrupt_bug
1115 zeroentry coprocessor_error do_coprocessor_error
1116 errorentry alignment_check do_alignment_check
1117 zeroentry simd_coprocessor_error do_simd_coprocessor_error
1120 /* Reload gs selector with exception handling */
1121 /* edi: new selector */
1122 ENTRY(native_load_gs_index)
1123 CFI_STARTPROC
1124 pushfq_cfi
1125 DISABLE_INTERRUPTS(CLBR_ANY & ~CLBR_RDI)
1126 SWAPGS
1127 gs_change:
1128 movl %edi,%gs
1129 2: mfence /* workaround */
1130 SWAPGS
1131 popfq_cfi
1132 ret
1133 CFI_ENDPROC
1134 END(native_load_gs_index)
1136 .section __ex_table,"a"
1137 .align 8
1138 .quad gs_change,bad_gs
1139 .previous
1140 .section .fixup,"ax"
1141 /* running with kernelgs */
1142 bad_gs:
1143 SWAPGS /* switch back to user gs */
1144 xorl %eax,%eax
1145 movl %eax,%gs
1146 jmp 2b
1147 .previous
1149 ENTRY(kernel_thread_helper)
1150 pushq $0 # fake return address
1151 CFI_STARTPROC
1152 /*
1153 * Here we are in the child and the registers are set as they were
1154 * at kernel_thread() invocation in the parent.
1155 */
1156 call *%rsi
1157 # exit
1158 mov %eax, %edi
1159 call do_exit
1160 ud2 # padding for call trace
1161 CFI_ENDPROC
1162 END(kernel_thread_helper)
1164 /*
1165 * execve(). This function needs to use IRET, not SYSRET, to set up all state properly.
1166 *
1167 * C extern interface:
1168 * extern long execve(const char *name, char **argv, char **envp)
1169 *
1170 * asm input arguments:
1171 * rdi: name, rsi: argv, rdx: envp
1172 *
1173 * We want to fallback into:
1174 * extern long sys_execve(const char *name, char **argv,char **envp, struct pt_regs *regs)
1175 *
1176 * do_sys_execve asm fallback arguments:
1177 * rdi: name, rsi: argv, rdx: envp, rcx: fake frame on the stack
1178 */
1179 ENTRY(kernel_execve)
1180 CFI_STARTPROC
1181 FAKE_STACK_FRAME $0
1182 SAVE_ALL
1183 movq %rsp,%rcx
1184 call sys_execve
1185 movq %rax, RAX(%rsp)
1186 RESTORE_REST
1187 testq %rax,%rax
1188 je int_ret_from_sys_call
1189 RESTORE_ARGS
1190 UNFAKE_STACK_FRAME
1191 ret
1192 CFI_ENDPROC
1193 END(kernel_execve)
1195 /* Call softirq on interrupt stack. Interrupts are off. */
1196 ENTRY(call_softirq)
1197 CFI_STARTPROC
1198 pushq_cfi %rbp
1199 CFI_REL_OFFSET rbp,0
1200 mov %rsp,%rbp
1201 CFI_DEF_CFA_REGISTER rbp
1202 incl PER_CPU_VAR(irq_count)
1203 cmove PER_CPU_VAR(irq_stack_ptr),%rsp
1204 push %rbp # backlink for old unwinder
1205 call __do_softirq
1206 leaveq
1207 CFI_RESTORE rbp
1208 CFI_DEF_CFA_REGISTER rsp
1209 CFI_ADJUST_CFA_OFFSET -8
1210 decl PER_CPU_VAR(irq_count)
1211 ret
1212 CFI_ENDPROC
1213 END(call_softirq)
1215 #ifdef CONFIG_XEN
1216 zeroentry xen_hypervisor_callback xen_do_hypervisor_callback
1218 /*
1219 * A note on the "critical region" in our callback handler.
1220 * We want to avoid stacking callback handlers due to events occurring
1221 * during handling of the last event. To do this, we keep events disabled
1222 * until we've done all processing. HOWEVER, we must enable events before
1223 * popping the stack frame (can't be done atomically) and so it would still
1224 * be possible to get enough handler activations to overflow the stack.
1225 * Although unlikely, bugs of that kind are hard to track down, so we'd
1226 * like to avoid the possibility.
1227 * So, on entry to the handler we detect whether we interrupted an
1228 * existing activation in its critical region -- if so, we pop the current
1229 * activation and restart the handler using the previous one.
1230 */
1231 ENTRY(xen_do_hypervisor_callback) # do_hypervisor_callback(struct *pt_regs)
1232 CFI_STARTPROC
1233 /*
1234 * Since we don't modify %rdi, evtchn_do_upall(struct *pt_regs) will
1235 * see the correct pointer to the pt_regs
1236 */
1237 movq %rdi, %rsp # we don't return, adjust the stack frame
1238 CFI_ENDPROC
1239 DEFAULT_FRAME
1240 11: incl PER_CPU_VAR(irq_count)
1241 movq %rsp,%rbp
1242 CFI_DEF_CFA_REGISTER rbp
1243 cmovzq PER_CPU_VAR(irq_stack_ptr),%rsp
1244 pushq %rbp # backlink for old unwinder
1245 call xen_evtchn_do_upcall
1246 popq %rsp
1247 CFI_DEF_CFA_REGISTER rsp
1248 decl PER_CPU_VAR(irq_count)
1249 jmp error_exit
1250 CFI_ENDPROC
1251 END(xen_do_hypervisor_callback)
1253 /*
1254 * Hypervisor uses this for application faults while it executes.
1255 * We get here for two reasons:
1256 * 1. Fault while reloading DS, ES, FS or GS
1257 * 2. Fault while executing IRET
1258 * Category 1 we do not need to fix up as Xen has already reloaded all segment
1259 * registers that could be reloaded and zeroed the others.
1260 * Category 2 we fix up by killing the current process. We cannot use the
1261 * normal Linux return path in this case because if we use the IRET hypercall
1262 * to pop the stack frame we end up in an infinite loop of failsafe callbacks.
1263 * We distinguish between categories by comparing each saved segment register
1264 * with its current contents: any discrepancy means we in category 1.
1265 */
1266 ENTRY(xen_failsafe_callback)
1267 INTR_FRAME 1 (6*8)
1268 /*CFI_REL_OFFSET gs,GS*/
1269 /*CFI_REL_OFFSET fs,FS*/
1270 /*CFI_REL_OFFSET es,ES*/
1271 /*CFI_REL_OFFSET ds,DS*/
1272 CFI_REL_OFFSET r11,8
1273 CFI_REL_OFFSET rcx,0
1274 movw %ds,%cx
1275 cmpw %cx,0x10(%rsp)
1276 CFI_REMEMBER_STATE
1277 jne 1f
1278 movw %es,%cx
1279 cmpw %cx,0x18(%rsp)
1280 jne 1f
1281 movw %fs,%cx
1282 cmpw %cx,0x20(%rsp)
1283 jne 1f
1284 movw %gs,%cx
1285 cmpw %cx,0x28(%rsp)
1286 jne 1f
1287 /* All segments match their saved values => Category 2 (Bad IRET). */
1288 movq (%rsp),%rcx
1289 CFI_RESTORE rcx
1290 movq 8(%rsp),%r11
1291 CFI_RESTORE r11
1292 addq $0x30,%rsp
1293 CFI_ADJUST_CFA_OFFSET -0x30
1294 pushq_cfi $0 /* RIP */
1295 pushq_cfi %r11
1296 pushq_cfi %rcx
1297 jmp general_protection
1298 CFI_RESTORE_STATE
1299 1: /* Segment mismatch => Category 1 (Bad segment). Retry the IRET. */
1300 movq (%rsp),%rcx
1301 CFI_RESTORE rcx
1302 movq 8(%rsp),%r11
1303 CFI_RESTORE r11
1304 addq $0x30,%rsp
1305 CFI_ADJUST_CFA_OFFSET -0x30
1306 pushq_cfi $0
1307 SAVE_ALL
1308 jmp error_exit
1309 CFI_ENDPROC
1310 END(xen_failsafe_callback)
1312 apicinterrupt XEN_HVM_EVTCHN_CALLBACK \
1313 xen_hvm_callback_vector xen_evtchn_do_upcall
1315 #endif /* CONFIG_XEN */
1317 /*
1318 * Some functions should be protected against kprobes
1319 */
1320 .pushsection .kprobes.text, "ax"
1322 paranoidzeroentry_ist debug do_debug DEBUG_STACK
1323 paranoidzeroentry_ist int3 do_int3 DEBUG_STACK
1324 paranoiderrorentry stack_segment do_stack_segment
1325 #ifdef CONFIG_XEN
1326 zeroentry xen_debug do_debug
1327 zeroentry xen_int3 do_int3
1328 errorentry xen_stack_segment do_stack_segment
1329 #endif
1330 errorentry general_protection do_general_protection
1331 errorentry page_fault do_page_fault
1332 #ifdef CONFIG_KVM_GUEST
1333 errorentry async_page_fault do_async_page_fault
1334 #endif
1335 #ifdef CONFIG_X86_MCE
1336 paranoidzeroentry machine_check *machine_check_vector(%rip)
1337 #endif
1339 /*
1340 * "Paranoid" exit path from exception stack.
1341 * Paranoid because this is used by NMIs and cannot take
1342 * any kernel state for granted.
1343 * We don't do kernel preemption checks here, because only
1344 * NMI should be common and it does not enable IRQs and
1345 * cannot get reschedule ticks.
1346 *
1347 * "trace" is 0 for the NMI handler only, because irq-tracing
1348 * is fundamentally NMI-unsafe. (we cannot change the soft and
1349 * hard flags at once, atomically)
1350 */
1352 /* ebx: no swapgs flag */
1353 ENTRY(paranoid_exit)
1354 DEFAULT_FRAME
1355 DISABLE_INTERRUPTS(CLBR_NONE)
1356 TRACE_IRQS_OFF
1357 testl %ebx,%ebx /* swapgs needed? */
1358 jnz paranoid_restore
1359 testl $3,CS(%rsp)
1360 jnz paranoid_userspace
1361 paranoid_swapgs:
1362 TRACE_IRQS_IRETQ 0
1363 SWAPGS_UNSAFE_STACK
1364 RESTORE_ALL 8
1365 jmp irq_return
1366 paranoid_restore:
1367 TRACE_IRQS_IRETQ 0
1368 RESTORE_ALL 8
1369 jmp irq_return
1370 paranoid_userspace:
1371 GET_THREAD_INFO(%rcx)
1372 movl TI_flags(%rcx),%ebx
1373 andl $_TIF_WORK_MASK,%ebx
1374 jz paranoid_swapgs
1375 movq %rsp,%rdi /* &pt_regs */
1376 call sync_regs
1377 movq %rax,%rsp /* switch stack for scheduling */
1378 testl $_TIF_NEED_RESCHED,%ebx
1379 jnz paranoid_schedule
1380 movl %ebx,%edx /* arg3: thread flags */
1381 TRACE_IRQS_ON
1382 ENABLE_INTERRUPTS(CLBR_NONE)
1383 xorl %esi,%esi /* arg2: oldset */
1384 movq %rsp,%rdi /* arg1: &pt_regs */
1385 call do_notify_resume
1386 DISABLE_INTERRUPTS(CLBR_NONE)
1387 TRACE_IRQS_OFF
1388 jmp paranoid_userspace
1389 paranoid_schedule:
1390 TRACE_IRQS_ON
1391 ENABLE_INTERRUPTS(CLBR_ANY)
1392 call schedule
1393 DISABLE_INTERRUPTS(CLBR_ANY)
1394 TRACE_IRQS_OFF
1395 jmp paranoid_userspace
1396 CFI_ENDPROC
1397 END(paranoid_exit)
1399 /*
1400 * Exception entry point. This expects an error code/orig_rax on the stack.
1401 * returns in "no swapgs flag" in %ebx.
1402 */
1403 ENTRY(error_entry)
1404 XCPT_FRAME
1405 CFI_ADJUST_CFA_OFFSET 15*8
1406 /* oldrax contains error code */
1407 cld
1408 movq_cfi rdi, RDI+8
1409 movq_cfi rsi, RSI+8
1410 movq_cfi rdx, RDX+8
1411 movq_cfi rcx, RCX+8
1412 movq_cfi rax, RAX+8
1413 movq_cfi r8, R8+8
1414 movq_cfi r9, R9+8
1415 movq_cfi r10, R10+8
1416 movq_cfi r11, R11+8
1417 movq_cfi rbx, RBX+8
1418 movq_cfi rbp, RBP+8
1419 movq_cfi r12, R12+8
1420 movq_cfi r13, R13+8
1421 movq_cfi r14, R14+8
1422 movq_cfi r15, R15+8
1423 xorl %ebx,%ebx
1424 testl $3,CS+8(%rsp)
1425 je error_kernelspace
1426 error_swapgs:
1427 SWAPGS
1428 error_sti:
1429 TRACE_IRQS_OFF
1430 ret
1432 /*
1433 * There are two places in the kernel that can potentially fault with
1434 * usergs. Handle them here. The exception handlers after iret run with
1435 * kernel gs again, so don't set the user space flag. B stepping K8s
1436 * sometimes report an truncated RIP for IRET exceptions returning to
1437 * compat mode. Check for these here too.
1438 */
1439 error_kernelspace:
1440 incl %ebx
1441 leaq irq_return(%rip),%rcx
1442 cmpq %rcx,RIP+8(%rsp)
1443 je error_swapgs
1444 movl %ecx,%eax /* zero extend */
1445 cmpq %rax,RIP+8(%rsp)
1446 je bstep_iret
1447 cmpq $gs_change,RIP+8(%rsp)
1448 je error_swapgs
1449 jmp error_sti
1451 bstep_iret:
1452 /* Fix truncated RIP */
1453 movq %rcx,RIP+8(%rsp)
1454 jmp error_swapgs
1455 CFI_ENDPROC
1456 END(error_entry)
1459 /* ebx: no swapgs flag (1: don't need swapgs, 0: need it) */
1460 ENTRY(error_exit)
1461 DEFAULT_FRAME
1462 movl %ebx,%eax
1463 RESTORE_REST
1464 DISABLE_INTERRUPTS(CLBR_NONE)
1465 TRACE_IRQS_OFF
1466 GET_THREAD_INFO(%rcx)
1467 testl %eax,%eax
1468 jne retint_kernel
1469 LOCKDEP_SYS_EXIT_IRQ
1470 movl TI_flags(%rcx),%edx
1471 movl $_TIF_WORK_MASK,%edi
1472 andl %edi,%edx
1473 jnz retint_careful
1474 jmp retint_swapgs
1475 CFI_ENDPROC
1476 END(error_exit)
1479 /* runs on exception stack */
1480 ENTRY(nmi)
1481 INTR_FRAME
1482 PARAVIRT_ADJUST_EXCEPTION_FRAME
1483 pushq_cfi $-1
1484 subq $ORIG_RAX-R15, %rsp
1485 CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15
1486 call save_paranoid
1487 DEFAULT_FRAME 0
1488 /* paranoidentry do_nmi, 0; without TRACE_IRQS_OFF */
1489 movq %rsp,%rdi
1490 movq $-1,%rsi
1491 call do_nmi
1492 #ifdef CONFIG_TRACE_IRQFLAGS
1493 /* paranoidexit; without TRACE_IRQS_OFF */
1494 /* ebx: no swapgs flag */
1495 DISABLE_INTERRUPTS(CLBR_NONE)
1496 testl %ebx,%ebx /* swapgs needed? */
1497 jnz nmi_restore
1498 testl $3,CS(%rsp)
1499 jnz nmi_userspace
1500 nmi_swapgs:
1501 SWAPGS_UNSAFE_STACK
1502 nmi_restore:
1503 RESTORE_ALL 8
1504 jmp irq_return
1505 nmi_userspace:
1506 GET_THREAD_INFO(%rcx)
1507 movl TI_flags(%rcx),%ebx
1508 andl $_TIF_WORK_MASK,%ebx
1509 jz nmi_swapgs
1510 movq %rsp,%rdi /* &pt_regs */
1511 call sync_regs
1512 movq %rax,%rsp /* switch stack for scheduling */
1513 testl $_TIF_NEED_RESCHED,%ebx
1514 jnz nmi_schedule
1515 movl %ebx,%edx /* arg3: thread flags */
1516 ENABLE_INTERRUPTS(CLBR_NONE)
1517 xorl %esi,%esi /* arg2: oldset */
1518 movq %rsp,%rdi /* arg1: &pt_regs */
1519 call do_notify_resume
1520 DISABLE_INTERRUPTS(CLBR_NONE)
1521 jmp nmi_userspace
1522 nmi_schedule:
1523 ENABLE_INTERRUPTS(CLBR_ANY)
1524 call schedule
1525 DISABLE_INTERRUPTS(CLBR_ANY)
1526 jmp nmi_userspace
1527 CFI_ENDPROC
1528 #else
1529 jmp paranoid_exit
1530 CFI_ENDPROC
1531 #endif
1532 END(nmi)
1534 ENTRY(ignore_sysret)
1535 CFI_STARTPROC
1536 mov $-ENOSYS,%eax
1537 sysret
1538 CFI_ENDPROC
1539 END(ignore_sysret)
1541 /*
1542 * End of kprobes section
1543 */
1544 .popsection