| blob | 1e96c3628bf24fc4fe0086ac6f9dc70b2c1c590d |
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>
58 #include <asm/asm.h>
59 #include <asm/context_tracking.h>
60 #include <asm/smap.h>
61 #include <linux/err.h>
63 /* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */
64 #include <linux/elf-em.h>
65 #define AUDIT_ARCH_X86_64 (EM_X86_64|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE)
66 #define __AUDIT_ARCH_64BIT 0x80000000
67 #define __AUDIT_ARCH_LE 0x40000000
69 .code64
70 .section .entry.text, "ax"
72 #ifdef CONFIG_FUNCTION_TRACER
74 #ifdef CC_USING_FENTRY
75 # define function_hook __fentry__
76 #else
77 # define function_hook mcount
78 #endif
80 #ifdef CONFIG_DYNAMIC_FTRACE
82 ENTRY(function_hook)
83 retq
84 END(function_hook)
86 /* skip is set if stack has been adjusted */
87 .macro ftrace_caller_setup skip=0
88 MCOUNT_SAVE_FRAME \skip
90 /* Load the ftrace_ops into the 3rd parameter */
91 movq function_trace_op(%rip), %rdx
93 /* Load ip into the first parameter */
94 movq RIP(%rsp), %rdi
95 subq $MCOUNT_INSN_SIZE, %rdi
96 /* Load the parent_ip into the second parameter */
97 #ifdef CC_USING_FENTRY
98 movq SS+16(%rsp), %rsi
99 #else
100 movq 8(%rbp), %rsi
101 #endif
102 .endm
104 ENTRY(ftrace_caller)
105 /* Check if tracing was disabled (quick check) */
106 cmpl $0, function_trace_stop
107 jne ftrace_stub
109 ftrace_caller_setup
110 /* regs go into 4th parameter (but make it NULL) */
111 movq $0, %rcx
113 GLOBAL(ftrace_call)
114 call ftrace_stub
116 MCOUNT_RESTORE_FRAME
117 ftrace_return:
119 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
120 GLOBAL(ftrace_graph_call)
121 jmp ftrace_stub
122 #endif
124 GLOBAL(ftrace_stub)
125 retq
126 END(ftrace_caller)
128 ENTRY(ftrace_regs_caller)
129 /* Save the current flags before compare (in SS location)*/
130 pushfq
132 /* Check if tracing was disabled (quick check) */
133 cmpl $0, function_trace_stop
134 jne ftrace_restore_flags
136 /* skip=8 to skip flags saved in SS */
137 ftrace_caller_setup 8
139 /* Save the rest of pt_regs */
140 movq %r15, R15(%rsp)
141 movq %r14, R14(%rsp)
142 movq %r13, R13(%rsp)
143 movq %r12, R12(%rsp)
144 movq %r11, R11(%rsp)
145 movq %r10, R10(%rsp)
146 movq %rbp, RBP(%rsp)
147 movq %rbx, RBX(%rsp)
148 /* Copy saved flags */
149 movq SS(%rsp), %rcx
150 movq %rcx, EFLAGS(%rsp)
151 /* Kernel segments */
152 movq $__KERNEL_DS, %rcx
153 movq %rcx, SS(%rsp)
154 movq $__KERNEL_CS, %rcx
155 movq %rcx, CS(%rsp)
156 /* Stack - skipping return address */
157 leaq SS+16(%rsp), %rcx
158 movq %rcx, RSP(%rsp)
160 /* regs go into 4th parameter */
161 leaq (%rsp), %rcx
163 GLOBAL(ftrace_regs_call)
164 call ftrace_stub
166 /* Copy flags back to SS, to restore them */
167 movq EFLAGS(%rsp), %rax
168 movq %rax, SS(%rsp)
170 /* Handlers can change the RIP */
171 movq RIP(%rsp), %rax
172 movq %rax, SS+8(%rsp)
174 /* restore the rest of pt_regs */
175 movq R15(%rsp), %r15
176 movq R14(%rsp), %r14
177 movq R13(%rsp), %r13
178 movq R12(%rsp), %r12
179 movq R10(%rsp), %r10
180 movq RBP(%rsp), %rbp
181 movq RBX(%rsp), %rbx
183 /* skip=8 to skip flags saved in SS */
184 MCOUNT_RESTORE_FRAME 8
186 /* Restore flags */
187 popfq
189 jmp ftrace_return
190 ftrace_restore_flags:
191 popfq
192 jmp ftrace_stub
194 END(ftrace_regs_caller)
197 #else /* ! CONFIG_DYNAMIC_FTRACE */
199 ENTRY(function_hook)
200 cmpl $0, function_trace_stop
201 jne ftrace_stub
203 cmpq $ftrace_stub, ftrace_trace_function
204 jnz trace
206 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
207 cmpq $ftrace_stub, ftrace_graph_return
208 jnz ftrace_graph_caller
210 cmpq $ftrace_graph_entry_stub, ftrace_graph_entry
211 jnz ftrace_graph_caller
212 #endif
214 GLOBAL(ftrace_stub)
215 retq
217 trace:
218 MCOUNT_SAVE_FRAME
220 movq RIP(%rsp), %rdi
221 #ifdef CC_USING_FENTRY
222 movq SS+16(%rsp), %rsi
223 #else
224 movq 8(%rbp), %rsi
225 #endif
226 subq $MCOUNT_INSN_SIZE, %rdi
228 call *ftrace_trace_function
230 MCOUNT_RESTORE_FRAME
232 jmp ftrace_stub
233 END(function_hook)
234 #endif /* CONFIG_DYNAMIC_FTRACE */
235 #endif /* CONFIG_FUNCTION_TRACER */
237 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
238 ENTRY(ftrace_graph_caller)
239 MCOUNT_SAVE_FRAME
241 #ifdef CC_USING_FENTRY
242 leaq SS+16(%rsp), %rdi
243 movq $0, %rdx /* No framepointers needed */
244 #else
245 leaq 8(%rbp), %rdi
246 movq (%rbp), %rdx
247 #endif
248 movq RIP(%rsp), %rsi
249 subq $MCOUNT_INSN_SIZE, %rsi
251 call prepare_ftrace_return
253 MCOUNT_RESTORE_FRAME
255 retq
256 END(ftrace_graph_caller)
258 GLOBAL(return_to_handler)
259 subq $24, %rsp
261 /* Save the return values */
262 movq %rax, (%rsp)
263 movq %rdx, 8(%rsp)
264 movq %rbp, %rdi
266 call ftrace_return_to_handler
268 movq %rax, %rdi
269 movq 8(%rsp), %rdx
270 movq (%rsp), %rax
271 addq $24, %rsp
272 jmp *%rdi
273 #endif
276 #ifndef CONFIG_PREEMPT
277 #define retint_kernel retint_restore_args
278 #endif
280 #ifdef CONFIG_PARAVIRT
281 ENTRY(native_usergs_sysret64)
282 swapgs
283 sysretq
284 ENDPROC(native_usergs_sysret64)
285 #endif /* CONFIG_PARAVIRT */
288 .macro TRACE_IRQS_IRETQ offset=ARGOFFSET
289 #ifdef CONFIG_TRACE_IRQFLAGS
290 bt $9,EFLAGS-\offset(%rsp) /* interrupts off? */
291 jnc 1f
292 TRACE_IRQS_ON
293 1:
294 #endif
295 .endm
297 /*
298 * When dynamic function tracer is enabled it will add a breakpoint
299 * to all locations that it is about to modify, sync CPUs, update
300 * all the code, sync CPUs, then remove the breakpoints. In this time
301 * if lockdep is enabled, it might jump back into the debug handler
302 * outside the updating of the IST protection. (TRACE_IRQS_ON/OFF).
303 *
304 * We need to change the IDT table before calling TRACE_IRQS_ON/OFF to
305 * make sure the stack pointer does not get reset back to the top
306 * of the debug stack, and instead just reuses the current stack.
307 */
308 #if defined(CONFIG_DYNAMIC_FTRACE) && defined(CONFIG_TRACE_IRQFLAGS)
310 .macro TRACE_IRQS_OFF_DEBUG
311 call debug_stack_set_zero
312 TRACE_IRQS_OFF
313 call debug_stack_reset
314 .endm
316 .macro TRACE_IRQS_ON_DEBUG
317 call debug_stack_set_zero
318 TRACE_IRQS_ON
319 call debug_stack_reset
320 .endm
322 .macro TRACE_IRQS_IRETQ_DEBUG offset=ARGOFFSET
323 bt $9,EFLAGS-\offset(%rsp) /* interrupts off? */
324 jnc 1f
325 TRACE_IRQS_ON_DEBUG
326 1:
327 .endm
329 #else
330 # define TRACE_IRQS_OFF_DEBUG TRACE_IRQS_OFF
331 # define TRACE_IRQS_ON_DEBUG TRACE_IRQS_ON
332 # define TRACE_IRQS_IRETQ_DEBUG TRACE_IRQS_IRETQ
333 #endif
335 /*
336 * C code is not supposed to know about undefined top of stack. Every time
337 * a C function with an pt_regs argument is called from the SYSCALL based
338 * fast path FIXUP_TOP_OF_STACK is needed.
339 * RESTORE_TOP_OF_STACK syncs the syscall state after any possible ptregs
340 * manipulation.
341 */
343 /* %rsp:at FRAMEEND */
344 .macro FIXUP_TOP_OF_STACK tmp offset=0
345 movq PER_CPU_VAR(old_rsp),\tmp
346 movq \tmp,RSP+\offset(%rsp)
347 movq $__USER_DS,SS+\offset(%rsp)
348 movq $__USER_CS,CS+\offset(%rsp)
349 movq $-1,RCX+\offset(%rsp)
350 movq R11+\offset(%rsp),\tmp /* get eflags */
351 movq \tmp,EFLAGS+\offset(%rsp)
352 .endm
354 .macro RESTORE_TOP_OF_STACK tmp offset=0
355 movq RSP+\offset(%rsp),\tmp
356 movq \tmp,PER_CPU_VAR(old_rsp)
357 movq EFLAGS+\offset(%rsp),\tmp
358 movq \tmp,R11+\offset(%rsp)
359 .endm
361 .macro FAKE_STACK_FRAME child_rip
362 /* push in order ss, rsp, eflags, cs, rip */
363 xorl %eax, %eax
364 pushq_cfi $__KERNEL_DS /* ss */
365 /*CFI_REL_OFFSET ss,0*/
366 pushq_cfi %rax /* rsp */
367 CFI_REL_OFFSET rsp,0
368 pushq_cfi $(X86_EFLAGS_IF|X86_EFLAGS_FIXED) /* eflags - interrupts on */
369 /*CFI_REL_OFFSET rflags,0*/
370 pushq_cfi $__KERNEL_CS /* cs */
371 /*CFI_REL_OFFSET cs,0*/
372 pushq_cfi \child_rip /* rip */
373 CFI_REL_OFFSET rip,0
374 pushq_cfi %rax /* orig rax */
375 .endm
377 .macro UNFAKE_STACK_FRAME
378 addq $8*6, %rsp
379 CFI_ADJUST_CFA_OFFSET -(6*8)
380 .endm
382 /*
383 * initial frame state for interrupts (and exceptions without error code)
384 */
385 .macro EMPTY_FRAME start=1 offset=0
386 .if \start
387 CFI_STARTPROC simple
388 CFI_SIGNAL_FRAME
389 CFI_DEF_CFA rsp,8+\offset
390 .else
391 CFI_DEF_CFA_OFFSET 8+\offset
392 .endif
393 .endm
395 /*
396 * initial frame state for interrupts (and exceptions without error code)
397 */
398 .macro INTR_FRAME start=1 offset=0
399 EMPTY_FRAME \start, SS+8+\offset-RIP
400 /*CFI_REL_OFFSET ss, SS+\offset-RIP*/
401 CFI_REL_OFFSET rsp, RSP+\offset-RIP
402 /*CFI_REL_OFFSET rflags, EFLAGS+\offset-RIP*/
403 /*CFI_REL_OFFSET cs, CS+\offset-RIP*/
404 CFI_REL_OFFSET rip, RIP+\offset-RIP
405 .endm
407 /*
408 * initial frame state for exceptions with error code (and interrupts
409 * with vector already pushed)
410 */
411 .macro XCPT_FRAME start=1 offset=0
412 INTR_FRAME \start, RIP+\offset-ORIG_RAX
413 /*CFI_REL_OFFSET orig_rax, ORIG_RAX-ORIG_RAX*/
414 .endm
416 /*
417 * frame that enables calling into C.
418 */
419 .macro PARTIAL_FRAME start=1 offset=0
420 XCPT_FRAME \start, ORIG_RAX+\offset-ARGOFFSET
421 CFI_REL_OFFSET rdi, RDI+\offset-ARGOFFSET
422 CFI_REL_OFFSET rsi, RSI+\offset-ARGOFFSET
423 CFI_REL_OFFSET rdx, RDX+\offset-ARGOFFSET
424 CFI_REL_OFFSET rcx, RCX+\offset-ARGOFFSET
425 CFI_REL_OFFSET rax, RAX+\offset-ARGOFFSET
426 CFI_REL_OFFSET r8, R8+\offset-ARGOFFSET
427 CFI_REL_OFFSET r9, R9+\offset-ARGOFFSET
428 CFI_REL_OFFSET r10, R10+\offset-ARGOFFSET
429 CFI_REL_OFFSET r11, R11+\offset-ARGOFFSET
430 .endm
432 /*
433 * frame that enables passing a complete pt_regs to a C function.
434 */
435 .macro DEFAULT_FRAME start=1 offset=0
436 PARTIAL_FRAME \start, R11+\offset-R15
437 CFI_REL_OFFSET rbx, RBX+\offset
438 CFI_REL_OFFSET rbp, RBP+\offset
439 CFI_REL_OFFSET r12, R12+\offset
440 CFI_REL_OFFSET r13, R13+\offset
441 CFI_REL_OFFSET r14, R14+\offset
442 CFI_REL_OFFSET r15, R15+\offset
443 .endm
445 /* save partial stack frame */
446 .macro SAVE_ARGS_IRQ
447 cld
448 /* start from rbp in pt_regs and jump over */
449 movq_cfi rdi, (RDI-RBP)
450 movq_cfi rsi, (RSI-RBP)
451 movq_cfi rdx, (RDX-RBP)
452 movq_cfi rcx, (RCX-RBP)
453 movq_cfi rax, (RAX-RBP)
454 movq_cfi r8, (R8-RBP)
455 movq_cfi r9, (R9-RBP)
456 movq_cfi r10, (R10-RBP)
457 movq_cfi r11, (R11-RBP)
459 /* Save rbp so that we can unwind from get_irq_regs() */
460 movq_cfi rbp, 0
462 /* Save previous stack value */
463 movq %rsp, %rsi
465 leaq -RBP(%rsp),%rdi /* arg1 for handler */
466 testl $3, CS-RBP(%rsi)
467 je 1f
468 SWAPGS
469 /*
470 * irq_count is used to check if a CPU is already on an interrupt stack
471 * or not. While this is essentially redundant with preempt_count it is
472 * a little cheaper to use a separate counter in the PDA (short of
473 * moving irq_enter into assembly, which would be too much work)
474 */
475 1: incl PER_CPU_VAR(irq_count)
476 cmovzq PER_CPU_VAR(irq_stack_ptr),%rsp
477 CFI_DEF_CFA_REGISTER rsi
479 /* Store previous stack value */
480 pushq %rsi
481 CFI_ESCAPE 0x0f /* DW_CFA_def_cfa_expression */, 6, \
482 0x77 /* DW_OP_breg7 */, 0, \
483 0x06 /* DW_OP_deref */, \
484 0x08 /* DW_OP_const1u */, SS+8-RBP, \
485 0x22 /* DW_OP_plus */
486 /* We entered an interrupt context - irqs are off: */
487 TRACE_IRQS_OFF
488 .endm
490 /* save complete stack frame */
491 .pushsection .kprobes.text, "ax"
492 ENTRY(save_paranoid)
493 XCPT_FRAME 1 RDI+8
494 cld
495 movq_cfi rdi, RDI+8
496 movq_cfi rsi, RSI+8
497 movq_cfi rdx, RDX+8
498 movq_cfi rcx, RCX+8
499 movq_cfi rax, RAX+8
500 movq_cfi r8, R8+8
501 movq_cfi r9, R9+8
502 movq_cfi r10, R10+8
503 movq_cfi r11, R11+8
504 movq_cfi rbx, RBX+8
505 movq_cfi rbp, RBP+8
506 movq_cfi r12, R12+8
507 movq_cfi r13, R13+8
508 movq_cfi r14, R14+8
509 movq_cfi r15, R15+8
510 movl $1,%ebx
511 movl $MSR_GS_BASE,%ecx
512 rdmsr
513 testl %edx,%edx
514 js 1f /* negative -> in kernel */
515 SWAPGS
516 xorl %ebx,%ebx
517 1: ret
518 CFI_ENDPROC
519 END(save_paranoid)
520 .popsection
522 /*
523 * A newly forked process directly context switches into this address.
524 *
525 * rdi: prev task we switched from
526 */
527 ENTRY(ret_from_fork)
528 DEFAULT_FRAME
530 LOCK ; btr $TIF_FORK,TI_flags(%r8)
532 pushq_cfi $0x0002
533 popfq_cfi # reset kernel eflags
535 call schedule_tail # rdi: 'prev' task parameter
537 GET_THREAD_INFO(%rcx)
539 RESTORE_REST
541 testl $3, CS-ARGOFFSET(%rsp) # from kernel_thread?
542 jz 1f
544 testl $_TIF_IA32, TI_flags(%rcx) # 32-bit compat task needs IRET
545 jnz int_ret_from_sys_call
547 RESTORE_TOP_OF_STACK %rdi, -ARGOFFSET
548 jmp ret_from_sys_call # go to the SYSRET fastpath
550 1:
551 subq $REST_SKIP, %rsp # leave space for volatiles
552 CFI_ADJUST_CFA_OFFSET REST_SKIP
553 movq %rbp, %rdi
554 call *%rbx
555 movl $0, RAX(%rsp)
556 RESTORE_REST
557 jmp int_ret_from_sys_call
558 CFI_ENDPROC
559 END(ret_from_fork)
561 /*
562 * System call entry. Up to 6 arguments in registers are supported.
563 *
564 * SYSCALL does not save anything on the stack and does not change the
565 * stack pointer. However, it does mask the flags register for us, so
566 * CLD and CLAC are not needed.
567 */
569 /*
570 * Register setup:
571 * rax system call number
572 * rdi arg0
573 * rcx return address for syscall/sysret, C arg3
574 * rsi arg1
575 * rdx arg2
576 * r10 arg3 (--> moved to rcx for C)
577 * r8 arg4
578 * r9 arg5
579 * r11 eflags for syscall/sysret, temporary for C
580 * r12-r15,rbp,rbx saved by C code, not touched.
581 *
582 * Interrupts are off on entry.
583 * Only called from user space.
584 *
585 * XXX if we had a free scratch register we could save the RSP into the stack frame
586 * and report it properly in ps. Unfortunately we haven't.
587 *
588 * When user can change the frames always force IRET. That is because
589 * it deals with uncanonical addresses better. SYSRET has trouble
590 * with them due to bugs in both AMD and Intel CPUs.
591 */
593 ENTRY(system_call)
594 CFI_STARTPROC simple
595 CFI_SIGNAL_FRAME
596 CFI_DEF_CFA rsp,KERNEL_STACK_OFFSET
597 CFI_REGISTER rip,rcx
598 /*CFI_REGISTER rflags,r11*/
599 SWAPGS_UNSAFE_STACK
600 /*
601 * A hypervisor implementation might want to use a label
602 * after the swapgs, so that it can do the swapgs
603 * for the guest and jump here on syscall.
604 */
605 GLOBAL(system_call_after_swapgs)
607 movq %rsp,PER_CPU_VAR(old_rsp)
608 movq PER_CPU_VAR(kernel_stack),%rsp
609 /*
610 * No need to follow this irqs off/on section - it's straight
611 * and short:
612 */
613 ENABLE_INTERRUPTS(CLBR_NONE)
614 SAVE_ARGS 8,0
615 movq %rax,ORIG_RAX-ARGOFFSET(%rsp)
616 movq %rcx,RIP-ARGOFFSET(%rsp)
617 CFI_REL_OFFSET rip,RIP-ARGOFFSET
618 testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
619 jnz tracesys
620 system_call_fastpath:
621 #if __SYSCALL_MASK == ~0
622 cmpq $__NR_syscall_max,%rax
623 #else
624 andl $__SYSCALL_MASK,%eax
625 cmpl $__NR_syscall_max,%eax
626 #endif
627 ja badsys
628 movq %r10,%rcx
629 call *sys_call_table(,%rax,8) # XXX: rip relative
630 movq %rax,RAX-ARGOFFSET(%rsp)
631 /*
632 * Syscall return path ending with SYSRET (fast path)
633 * Has incomplete stack frame and undefined top of stack.
634 */
635 ret_from_sys_call:
636 movl $_TIF_ALLWORK_MASK,%edi
637 /* edi: flagmask */
638 sysret_check:
639 LOCKDEP_SYS_EXIT
640 DISABLE_INTERRUPTS(CLBR_NONE)
641 TRACE_IRQS_OFF
642 movl TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET),%edx
643 andl %edi,%edx
644 jnz sysret_careful
645 CFI_REMEMBER_STATE
646 /*
647 * sysretq will re-enable interrupts:
648 */
649 TRACE_IRQS_ON
650 movq RIP-ARGOFFSET(%rsp),%rcx
651 CFI_REGISTER rip,rcx
652 RESTORE_ARGS 1,-ARG_SKIP,0
653 /*CFI_REGISTER rflags,r11*/
654 movq PER_CPU_VAR(old_rsp), %rsp
655 USERGS_SYSRET64
657 CFI_RESTORE_STATE
658 /* Handle reschedules */
659 /* edx: work, edi: workmask */
660 sysret_careful:
661 bt $TIF_NEED_RESCHED,%edx
662 jnc sysret_signal
663 TRACE_IRQS_ON
664 ENABLE_INTERRUPTS(CLBR_NONE)
665 pushq_cfi %rdi
666 SCHEDULE_USER
667 popq_cfi %rdi
668 jmp sysret_check
670 /* Handle a signal */
671 sysret_signal:
672 TRACE_IRQS_ON
673 ENABLE_INTERRUPTS(CLBR_NONE)
674 #ifdef CONFIG_AUDITSYSCALL
675 bt $TIF_SYSCALL_AUDIT,%edx
676 jc sysret_audit
677 #endif
678 /*
679 * We have a signal, or exit tracing or single-step.
680 * These all wind up with the iret return path anyway,
681 * so just join that path right now.
682 */
683 FIXUP_TOP_OF_STACK %r11, -ARGOFFSET
684 jmp int_check_syscall_exit_work
686 badsys:
687 movq $-ENOSYS,RAX-ARGOFFSET(%rsp)
688 jmp ret_from_sys_call
690 #ifdef CONFIG_AUDITSYSCALL
691 /*
692 * Fast path for syscall audit without full syscall trace.
693 * We just call __audit_syscall_entry() directly, and then
694 * jump back to the normal fast path.
695 */
696 auditsys:
697 movq %r10,%r9 /* 6th arg: 4th syscall arg */
698 movq %rdx,%r8 /* 5th arg: 3rd syscall arg */
699 movq %rsi,%rcx /* 4th arg: 2nd syscall arg */
700 movq %rdi,%rdx /* 3rd arg: 1st syscall arg */
701 movq %rax,%rsi /* 2nd arg: syscall number */
702 movl $AUDIT_ARCH_X86_64,%edi /* 1st arg: audit arch */
703 call __audit_syscall_entry
704 LOAD_ARGS 0 /* reload call-clobbered registers */
705 jmp system_call_fastpath
707 /*
708 * Return fast path for syscall audit. Call __audit_syscall_exit()
709 * directly and then jump back to the fast path with TIF_SYSCALL_AUDIT
710 * masked off.
711 */
712 sysret_audit:
713 movq RAX-ARGOFFSET(%rsp),%rsi /* second arg, syscall return value */
714 cmpq $-MAX_ERRNO,%rsi /* is it < -MAX_ERRNO? */
715 setbe %al /* 1 if so, 0 if not */
716 movzbl %al,%edi /* zero-extend that into %edi */
717 call __audit_syscall_exit
718 movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),%edi
719 jmp sysret_check
720 #endif /* CONFIG_AUDITSYSCALL */
722 /* Do syscall tracing */
723 tracesys:
724 #ifdef CONFIG_AUDITSYSCALL
725 testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
726 jz auditsys
727 #endif
728 SAVE_REST
729 movq $-ENOSYS,RAX(%rsp) /* ptrace can change this for a bad syscall */
730 FIXUP_TOP_OF_STACK %rdi
731 movq %rsp,%rdi
732 call syscall_trace_enter
733 /*
734 * Reload arg registers from stack in case ptrace changed them.
735 * We don't reload %rax because syscall_trace_enter() returned
736 * the value it wants us to use in the table lookup.
737 */
738 LOAD_ARGS ARGOFFSET, 1
739 RESTORE_REST
740 #if __SYSCALL_MASK == ~0
741 cmpq $__NR_syscall_max,%rax
742 #else
743 andl $__SYSCALL_MASK,%eax
744 cmpl $__NR_syscall_max,%eax
745 #endif
746 ja int_ret_from_sys_call /* RAX(%rsp) set to -ENOSYS above */
747 movq %r10,%rcx /* fixup for C */
748 call *sys_call_table(,%rax,8)
749 movq %rax,RAX-ARGOFFSET(%rsp)
750 /* Use IRET because user could have changed frame */
752 /*
753 * Syscall return path ending with IRET.
754 * Has correct top of stack, but partial stack frame.
755 */
756 GLOBAL(int_ret_from_sys_call)
757 DISABLE_INTERRUPTS(CLBR_NONE)
758 TRACE_IRQS_OFF
759 movl $_TIF_ALLWORK_MASK,%edi
760 /* edi: mask to check */
761 GLOBAL(int_with_check)
762 LOCKDEP_SYS_EXIT_IRQ
763 GET_THREAD_INFO(%rcx)
764 movl TI_flags(%rcx),%edx
765 andl %edi,%edx
766 jnz int_careful
767 andl $~TS_COMPAT,TI_status(%rcx)
768 jmp retint_swapgs
770 /* Either reschedule or signal or syscall exit tracking needed. */
771 /* First do a reschedule test. */
772 /* edx: work, edi: workmask */
773 int_careful:
774 bt $TIF_NEED_RESCHED,%edx
775 jnc int_very_careful
776 TRACE_IRQS_ON
777 ENABLE_INTERRUPTS(CLBR_NONE)
778 pushq_cfi %rdi
779 SCHEDULE_USER
780 popq_cfi %rdi
781 DISABLE_INTERRUPTS(CLBR_NONE)
782 TRACE_IRQS_OFF
783 jmp int_with_check
785 /* handle signals and tracing -- both require a full stack frame */
786 int_very_careful:
787 TRACE_IRQS_ON
788 ENABLE_INTERRUPTS(CLBR_NONE)
789 int_check_syscall_exit_work:
790 SAVE_REST
791 /* Check for syscall exit trace */
792 testl $_TIF_WORK_SYSCALL_EXIT,%edx
793 jz int_signal
794 pushq_cfi %rdi
795 leaq 8(%rsp),%rdi # &ptregs -> arg1
796 call syscall_trace_leave
797 popq_cfi %rdi
798 andl $~(_TIF_WORK_SYSCALL_EXIT|_TIF_SYSCALL_EMU),%edi
799 jmp int_restore_rest
801 int_signal:
802 testl $_TIF_DO_NOTIFY_MASK,%edx
803 jz 1f
804 movq %rsp,%rdi # &ptregs -> arg1
805 xorl %esi,%esi # oldset -> arg2
806 call do_notify_resume
807 1: movl $_TIF_WORK_MASK,%edi
808 int_restore_rest:
809 RESTORE_REST
810 DISABLE_INTERRUPTS(CLBR_NONE)
811 TRACE_IRQS_OFF
812 jmp int_with_check
813 CFI_ENDPROC
814 END(system_call)
816 .macro FORK_LIKE func
817 ENTRY(stub_\func)
818 CFI_STARTPROC
819 popq %r11 /* save return address */
820 PARTIAL_FRAME 0
821 SAVE_REST
822 pushq %r11 /* put it back on stack */
823 FIXUP_TOP_OF_STACK %r11, 8
824 DEFAULT_FRAME 0 8 /* offset 8: return address */
825 call sys_\func
826 RESTORE_TOP_OF_STACK %r11, 8
827 ret $REST_SKIP /* pop extended registers */
828 CFI_ENDPROC
829 END(stub_\func)
830 .endm
832 .macro FIXED_FRAME label,func
833 ENTRY(\label)
834 CFI_STARTPROC
835 PARTIAL_FRAME 0 8 /* offset 8: return address */
836 FIXUP_TOP_OF_STACK %r11, 8-ARGOFFSET
837 call \func
838 RESTORE_TOP_OF_STACK %r11, 8-ARGOFFSET
839 ret
840 CFI_ENDPROC
841 END(\label)
842 .endm
844 FORK_LIKE clone
845 FORK_LIKE fork
846 FORK_LIKE vfork
847 FIXED_FRAME stub_iopl, sys_iopl
849 ENTRY(ptregscall_common)
850 DEFAULT_FRAME 1 8 /* offset 8: return address */
851 RESTORE_TOP_OF_STACK %r11, 8
852 movq_cfi_restore R15+8, r15
853 movq_cfi_restore R14+8, r14
854 movq_cfi_restore R13+8, r13
855 movq_cfi_restore R12+8, r12
856 movq_cfi_restore RBP+8, rbp
857 movq_cfi_restore RBX+8, rbx
858 ret $REST_SKIP /* pop extended registers */
859 CFI_ENDPROC
860 END(ptregscall_common)
862 ENTRY(stub_execve)
863 CFI_STARTPROC
864 addq $8, %rsp
865 PARTIAL_FRAME 0
866 SAVE_REST
867 FIXUP_TOP_OF_STACK %r11
868 call sys_execve
869 movq %rax,RAX(%rsp)
870 RESTORE_REST
871 jmp int_ret_from_sys_call
872 CFI_ENDPROC
873 END(stub_execve)
875 /*
876 * sigreturn is special because it needs to restore all registers on return.
877 * This cannot be done with SYSRET, so use the IRET return path instead.
878 */
879 ENTRY(stub_rt_sigreturn)
880 CFI_STARTPROC
881 addq $8, %rsp
882 PARTIAL_FRAME 0
883 SAVE_REST
884 FIXUP_TOP_OF_STACK %r11
885 call sys_rt_sigreturn
886 movq %rax,RAX(%rsp) # fixme, this could be done at the higher layer
887 RESTORE_REST
888 jmp int_ret_from_sys_call
889 CFI_ENDPROC
890 END(stub_rt_sigreturn)
892 #ifdef CONFIG_X86_X32_ABI
893 ENTRY(stub_x32_rt_sigreturn)
894 CFI_STARTPROC
895 addq $8, %rsp
896 PARTIAL_FRAME 0
897 SAVE_REST
898 FIXUP_TOP_OF_STACK %r11
899 call sys32_x32_rt_sigreturn
900 movq %rax,RAX(%rsp) # fixme, this could be done at the higher layer
901 RESTORE_REST
902 jmp int_ret_from_sys_call
903 CFI_ENDPROC
904 END(stub_x32_rt_sigreturn)
906 ENTRY(stub_x32_execve)
907 CFI_STARTPROC
908 addq $8, %rsp
909 PARTIAL_FRAME 0
910 SAVE_REST
911 FIXUP_TOP_OF_STACK %r11
912 call compat_sys_execve
913 RESTORE_TOP_OF_STACK %r11
914 movq %rax,RAX(%rsp)
915 RESTORE_REST
916 jmp int_ret_from_sys_call
917 CFI_ENDPROC
918 END(stub_x32_execve)
920 #endif
922 /*
923 * Build the entry stubs and pointer table with some assembler magic.
924 * We pack 7 stubs into a single 32-byte chunk, which will fit in a
925 * single cache line on all modern x86 implementations.
926 */
927 .section .init.rodata,"a"
928 ENTRY(interrupt)
929 .section .entry.text
930 .p2align 5
931 .p2align CONFIG_X86_L1_CACHE_SHIFT
932 ENTRY(irq_entries_start)
933 INTR_FRAME
934 vector=FIRST_EXTERNAL_VECTOR
935 .rept (NR_VECTORS-FIRST_EXTERNAL_VECTOR+6)/7
936 .balign 32
937 .rept 7
938 .if vector < NR_VECTORS
939 .if vector <> FIRST_EXTERNAL_VECTOR
940 CFI_ADJUST_CFA_OFFSET -8
941 .endif
942 1: pushq_cfi $(~vector+0x80) /* Note: always in signed byte range */
943 .if ((vector-FIRST_EXTERNAL_VECTOR)%7) <> 6
944 jmp 2f
945 .endif
946 .previous
947 .quad 1b
948 .section .entry.text
949 vector=vector+1
950 .endif
951 .endr
952 2: jmp common_interrupt
953 .endr
954 CFI_ENDPROC
955 END(irq_entries_start)
957 .previous
958 END(interrupt)
959 .previous
961 /*
962 * Interrupt entry/exit.
963 *
964 * Interrupt entry points save only callee clobbered registers in fast path.
965 *
966 * Entry runs with interrupts off.
967 */
969 /* 0(%rsp): ~(interrupt number) */
970 .macro interrupt func
971 /* reserve pt_regs for scratch regs and rbp */
972 subq $ORIG_RAX-RBP, %rsp
973 CFI_ADJUST_CFA_OFFSET ORIG_RAX-RBP
974 SAVE_ARGS_IRQ
975 call \func
976 .endm
978 /*
979 * Interrupt entry/exit should be protected against kprobes
980 */
981 .pushsection .kprobes.text, "ax"
982 /*
983 * The interrupt stubs push (~vector+0x80) onto the stack and
984 * then jump to common_interrupt.
985 */
986 .p2align CONFIG_X86_L1_CACHE_SHIFT
987 common_interrupt:
988 XCPT_FRAME
989 ASM_CLAC
990 addq $-0x80,(%rsp) /* Adjust vector to [-256,-1] range */
991 interrupt do_IRQ
992 /* 0(%rsp): old_rsp-ARGOFFSET */
993 ret_from_intr:
994 DISABLE_INTERRUPTS(CLBR_NONE)
995 TRACE_IRQS_OFF
996 decl PER_CPU_VAR(irq_count)
998 /* Restore saved previous stack */
999 popq %rsi
1000 CFI_DEF_CFA rsi,SS+8-RBP /* reg/off reset after def_cfa_expr */
1001 leaq ARGOFFSET-RBP(%rsi), %rsp
1002 CFI_DEF_CFA_REGISTER rsp
1003 CFI_ADJUST_CFA_OFFSET RBP-ARGOFFSET
1005 exit_intr:
1006 GET_THREAD_INFO(%rcx)
1007 testl $3,CS-ARGOFFSET(%rsp)
1008 je retint_kernel
1010 /* Interrupt came from user space */
1011 /*
1012 * Has a correct top of stack, but a partial stack frame
1013 * %rcx: thread info. Interrupts off.
1014 */
1015 retint_with_reschedule:
1016 movl $_TIF_WORK_MASK,%edi
1017 retint_check:
1018 LOCKDEP_SYS_EXIT_IRQ
1019 movl TI_flags(%rcx),%edx
1020 andl %edi,%edx
1021 CFI_REMEMBER_STATE
1022 jnz retint_careful
1024 retint_swapgs: /* return to user-space */
1025 /*
1026 * The iretq could re-enable interrupts:
1027 */
1028 DISABLE_INTERRUPTS(CLBR_ANY)
1029 TRACE_IRQS_IRETQ
1030 SWAPGS
1031 jmp restore_args
1033 retint_restore_args: /* return to kernel space */
1034 DISABLE_INTERRUPTS(CLBR_ANY)
1035 /*
1036 * The iretq could re-enable interrupts:
1037 */
1038 TRACE_IRQS_IRETQ
1039 restore_args:
1040 RESTORE_ARGS 1,8,1
1042 irq_return:
1043 INTERRUPT_RETURN
1044 _ASM_EXTABLE(irq_return, bad_iret)
1046 #ifdef CONFIG_PARAVIRT
1047 ENTRY(native_iret)
1048 iretq
1049 _ASM_EXTABLE(native_iret, bad_iret)
1050 #endif
1052 .section .fixup,"ax"
1053 bad_iret:
1054 /*
1055 * The iret traps when the %cs or %ss being restored is bogus.
1056 * We've lost the original trap vector and error code.
1057 * #GPF is the most likely one to get for an invalid selector.
1058 * So pretend we completed the iret and took the #GPF in user mode.
1059 *
1060 * We are now running with the kernel GS after exception recovery.
1061 * But error_entry expects us to have user GS to match the user %cs,
1062 * so swap back.
1063 */
1064 pushq $0
1066 SWAPGS
1067 jmp general_protection
1069 .previous
1071 /* edi: workmask, edx: work */
1072 retint_careful:
1073 CFI_RESTORE_STATE
1074 bt $TIF_NEED_RESCHED,%edx
1075 jnc retint_signal
1076 TRACE_IRQS_ON
1077 ENABLE_INTERRUPTS(CLBR_NONE)
1078 pushq_cfi %rdi
1079 SCHEDULE_USER
1080 popq_cfi %rdi
1081 GET_THREAD_INFO(%rcx)
1082 DISABLE_INTERRUPTS(CLBR_NONE)
1083 TRACE_IRQS_OFF
1084 jmp retint_check
1086 retint_signal:
1087 testl $_TIF_DO_NOTIFY_MASK,%edx
1088 jz retint_swapgs
1089 TRACE_IRQS_ON
1090 ENABLE_INTERRUPTS(CLBR_NONE)
1091 SAVE_REST
1092 movq $-1,ORIG_RAX(%rsp)
1093 xorl %esi,%esi # oldset
1094 movq %rsp,%rdi # &pt_regs
1095 call do_notify_resume
1096 RESTORE_REST
1097 DISABLE_INTERRUPTS(CLBR_NONE)
1098 TRACE_IRQS_OFF
1099 GET_THREAD_INFO(%rcx)
1100 jmp retint_with_reschedule
1102 #ifdef CONFIG_PREEMPT
1103 /* Returning to kernel space. Check if we need preemption */
1104 /* rcx: threadinfo. interrupts off. */
1105 ENTRY(retint_kernel)
1106 cmpl $0,PER_CPU_VAR(__preempt_count)
1107 jnz retint_restore_args
1108 bt $9,EFLAGS-ARGOFFSET(%rsp) /* interrupts off? */
1109 jnc retint_restore_args
1110 call preempt_schedule_irq
1111 jmp exit_intr
1112 #endif
1114 CFI_ENDPROC
1115 END(common_interrupt)
1116 /*
1117 * End of kprobes section
1118 */
1119 .popsection
1121 /*
1122 * APIC interrupts.
1123 */
1124 .macro apicinterrupt3 num sym do_sym
1125 ENTRY(\sym)
1126 INTR_FRAME
1127 ASM_CLAC
1128 pushq_cfi $~(\num)
1129 .Lcommon_\sym:
1130 interrupt \do_sym
1131 jmp ret_from_intr
1132 CFI_ENDPROC
1133 END(\sym)
1134 .endm
1136 #ifdef CONFIG_TRACING
1137 #define trace(sym) trace_##sym
1138 #define smp_trace(sym) smp_trace_##sym
1140 .macro trace_apicinterrupt num sym
1141 apicinterrupt3 \num trace(\sym) smp_trace(\sym)
1142 .endm
1143 #else
1144 .macro trace_apicinterrupt num sym do_sym
1145 .endm
1146 #endif
1148 .macro apicinterrupt num sym do_sym
1149 apicinterrupt3 \num \sym \do_sym
1150 trace_apicinterrupt \num \sym
1151 .endm
1153 #ifdef CONFIG_SMP
1154 apicinterrupt3 IRQ_MOVE_CLEANUP_VECTOR \
1155 irq_move_cleanup_interrupt smp_irq_move_cleanup_interrupt
1156 apicinterrupt3 REBOOT_VECTOR \
1157 reboot_interrupt smp_reboot_interrupt
1158 #endif
1160 #ifdef CONFIG_X86_UV
1161 apicinterrupt3 UV_BAU_MESSAGE \
1162 uv_bau_message_intr1 uv_bau_message_interrupt
1163 #endif
1164 apicinterrupt LOCAL_TIMER_VECTOR \
1165 apic_timer_interrupt smp_apic_timer_interrupt
1166 apicinterrupt X86_PLATFORM_IPI_VECTOR \
1167 x86_platform_ipi smp_x86_platform_ipi
1169 #ifdef CONFIG_HAVE_KVM
1170 apicinterrupt3 POSTED_INTR_VECTOR \
1171 kvm_posted_intr_ipi smp_kvm_posted_intr_ipi
1172 #endif
1174 #ifdef CONFIG_X86_MCE_THRESHOLD
1175 apicinterrupt THRESHOLD_APIC_VECTOR \
1176 threshold_interrupt smp_threshold_interrupt
1177 #endif
1179 #ifdef CONFIG_X86_THERMAL_VECTOR
1180 apicinterrupt THERMAL_APIC_VECTOR \
1181 thermal_interrupt smp_thermal_interrupt
1182 #endif
1184 #ifdef CONFIG_SMP
1185 apicinterrupt CALL_FUNCTION_SINGLE_VECTOR \
1186 call_function_single_interrupt smp_call_function_single_interrupt
1187 apicinterrupt CALL_FUNCTION_VECTOR \
1188 call_function_interrupt smp_call_function_interrupt
1189 apicinterrupt RESCHEDULE_VECTOR \
1190 reschedule_interrupt smp_reschedule_interrupt
1191 #endif
1193 apicinterrupt ERROR_APIC_VECTOR \
1194 error_interrupt smp_error_interrupt
1195 apicinterrupt SPURIOUS_APIC_VECTOR \
1196 spurious_interrupt smp_spurious_interrupt
1198 #ifdef CONFIG_IRQ_WORK
1199 apicinterrupt IRQ_WORK_VECTOR \
1200 irq_work_interrupt smp_irq_work_interrupt
1201 #endif
1203 /*
1204 * Exception entry points.
1205 */
1206 .macro zeroentry sym do_sym
1207 ENTRY(\sym)
1208 INTR_FRAME
1209 ASM_CLAC
1210 PARAVIRT_ADJUST_EXCEPTION_FRAME
1211 pushq_cfi $-1 /* ORIG_RAX: no syscall to restart */
1212 subq $ORIG_RAX-R15, %rsp
1213 CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15
1214 call error_entry
1215 DEFAULT_FRAME 0
1216 movq %rsp,%rdi /* pt_regs pointer */
1217 xorl %esi,%esi /* no error code */
1218 call \do_sym
1219 jmp error_exit /* %ebx: no swapgs flag */
1220 CFI_ENDPROC
1221 END(\sym)
1222 .endm
1224 .macro paranoidzeroentry sym do_sym
1225 ENTRY(\sym)
1226 INTR_FRAME
1227 ASM_CLAC
1228 PARAVIRT_ADJUST_EXCEPTION_FRAME
1229 pushq_cfi $-1 /* ORIG_RAX: no syscall to restart */
1230 subq $ORIG_RAX-R15, %rsp
1231 CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15
1232 call save_paranoid
1233 TRACE_IRQS_OFF
1234 movq %rsp,%rdi /* pt_regs pointer */
1235 xorl %esi,%esi /* no error code */
1236 call \do_sym
1237 jmp paranoid_exit /* %ebx: no swapgs flag */
1238 CFI_ENDPROC
1239 END(\sym)
1240 .endm
1242 #define INIT_TSS_IST(x) PER_CPU_VAR(init_tss) + (TSS_ist + ((x) - 1) * 8)
1243 .macro paranoidzeroentry_ist sym do_sym ist
1244 ENTRY(\sym)
1245 INTR_FRAME
1246 ASM_CLAC
1247 PARAVIRT_ADJUST_EXCEPTION_FRAME
1248 pushq_cfi $-1 /* ORIG_RAX: no syscall to restart */
1249 subq $ORIG_RAX-R15, %rsp
1250 CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15
1251 call save_paranoid
1252 TRACE_IRQS_OFF_DEBUG
1253 movq %rsp,%rdi /* pt_regs pointer */
1254 xorl %esi,%esi /* no error code */
1255 subq $EXCEPTION_STKSZ, INIT_TSS_IST(\ist)
1256 call \do_sym
1257 addq $EXCEPTION_STKSZ, INIT_TSS_IST(\ist)
1258 jmp paranoid_exit /* %ebx: no swapgs flag */
1259 CFI_ENDPROC
1260 END(\sym)
1261 .endm
1263 .macro errorentry sym do_sym
1264 ENTRY(\sym)
1265 XCPT_FRAME
1266 ASM_CLAC
1267 PARAVIRT_ADJUST_EXCEPTION_FRAME
1268 subq $ORIG_RAX-R15, %rsp
1269 CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15
1270 call error_entry
1271 DEFAULT_FRAME 0
1272 movq %rsp,%rdi /* pt_regs pointer */
1273 movq ORIG_RAX(%rsp),%rsi /* get error code */
1274 movq $-1,ORIG_RAX(%rsp) /* no syscall to restart */
1275 call \do_sym
1276 jmp error_exit /* %ebx: no swapgs flag */
1277 CFI_ENDPROC
1278 END(\sym)
1279 .endm
1281 #ifdef CONFIG_TRACING
1282 .macro trace_errorentry sym do_sym
1283 errorentry trace(\sym) trace(\do_sym)
1284 errorentry \sym \do_sym
1285 .endm
1286 #else
1287 .macro trace_errorentry sym do_sym
1288 errorentry \sym \do_sym
1289 .endm
1290 #endif
1292 /* error code is on the stack already */
1293 .macro paranoiderrorentry sym do_sym
1294 ENTRY(\sym)
1295 XCPT_FRAME
1296 ASM_CLAC
1297 PARAVIRT_ADJUST_EXCEPTION_FRAME
1298 subq $ORIG_RAX-R15, %rsp
1299 CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15
1300 call save_paranoid
1301 DEFAULT_FRAME 0
1302 TRACE_IRQS_OFF
1303 movq %rsp,%rdi /* pt_regs pointer */
1304 movq ORIG_RAX(%rsp),%rsi /* get error code */
1305 movq $-1,ORIG_RAX(%rsp) /* no syscall to restart */
1306 call \do_sym
1307 jmp paranoid_exit /* %ebx: no swapgs flag */
1308 CFI_ENDPROC
1309 END(\sym)
1310 .endm
1312 zeroentry divide_error do_divide_error
1313 zeroentry overflow do_overflow
1314 zeroentry bounds do_bounds
1315 zeroentry invalid_op do_invalid_op
1316 zeroentry device_not_available do_device_not_available
1317 paranoiderrorentry double_fault do_double_fault
1318 zeroentry coprocessor_segment_overrun do_coprocessor_segment_overrun
1319 errorentry invalid_TSS do_invalid_TSS
1320 errorentry segment_not_present do_segment_not_present
1321 zeroentry spurious_interrupt_bug do_spurious_interrupt_bug
1322 zeroentry coprocessor_error do_coprocessor_error
1323 errorentry alignment_check do_alignment_check
1324 zeroentry simd_coprocessor_error do_simd_coprocessor_error
1327 /* Reload gs selector with exception handling */
1328 /* edi: new selector */
1329 ENTRY(native_load_gs_index)
1330 CFI_STARTPROC
1331 pushfq_cfi
1332 DISABLE_INTERRUPTS(CLBR_ANY & ~CLBR_RDI)
1333 SWAPGS
1334 gs_change:
1335 movl %edi,%gs
1336 2: mfence /* workaround */
1337 SWAPGS
1338 popfq_cfi
1339 ret
1340 CFI_ENDPROC
1341 END(native_load_gs_index)
1343 _ASM_EXTABLE(gs_change,bad_gs)
1344 .section .fixup,"ax"
1345 /* running with kernelgs */
1346 bad_gs:
1347 SWAPGS /* switch back to user gs */
1348 xorl %eax,%eax
1349 movl %eax,%gs
1350 jmp 2b
1351 .previous
1353 /* Call softirq on interrupt stack. Interrupts are off. */
1354 ENTRY(do_softirq_own_stack)
1355 CFI_STARTPROC
1356 pushq_cfi %rbp
1357 CFI_REL_OFFSET rbp,0
1358 mov %rsp,%rbp
1359 CFI_DEF_CFA_REGISTER rbp
1360 incl PER_CPU_VAR(irq_count)
1361 cmove PER_CPU_VAR(irq_stack_ptr),%rsp
1362 push %rbp # backlink for old unwinder
1363 call __do_softirq
1364 leaveq
1365 CFI_RESTORE rbp
1366 CFI_DEF_CFA_REGISTER rsp
1367 CFI_ADJUST_CFA_OFFSET -8
1368 decl PER_CPU_VAR(irq_count)
1369 ret
1370 CFI_ENDPROC
1371 END(do_softirq_own_stack)
1373 #ifdef CONFIG_XEN
1374 zeroentry xen_hypervisor_callback xen_do_hypervisor_callback
1376 /*
1377 * A note on the "critical region" in our callback handler.
1378 * We want to avoid stacking callback handlers due to events occurring
1379 * during handling of the last event. To do this, we keep events disabled
1380 * until we've done all processing. HOWEVER, we must enable events before
1381 * popping the stack frame (can't be done atomically) and so it would still
1382 * be possible to get enough handler activations to overflow the stack.
1383 * Although unlikely, bugs of that kind are hard to track down, so we'd
1384 * like to avoid the possibility.
1385 * So, on entry to the handler we detect whether we interrupted an
1386 * existing activation in its critical region -- if so, we pop the current
1387 * activation and restart the handler using the previous one.
1388 */
1389 ENTRY(xen_do_hypervisor_callback) # do_hypervisor_callback(struct *pt_regs)
1390 CFI_STARTPROC
1391 /*
1392 * Since we don't modify %rdi, evtchn_do_upall(struct *pt_regs) will
1393 * see the correct pointer to the pt_regs
1394 */
1395 movq %rdi, %rsp # we don't return, adjust the stack frame
1396 CFI_ENDPROC
1397 DEFAULT_FRAME
1398 11: incl PER_CPU_VAR(irq_count)
1399 movq %rsp,%rbp
1400 CFI_DEF_CFA_REGISTER rbp
1401 cmovzq PER_CPU_VAR(irq_stack_ptr),%rsp
1402 pushq %rbp # backlink for old unwinder
1403 call xen_evtchn_do_upcall
1404 popq %rsp
1405 CFI_DEF_CFA_REGISTER rsp
1406 decl PER_CPU_VAR(irq_count)
1407 jmp error_exit
1408 CFI_ENDPROC
1409 END(xen_do_hypervisor_callback)
1411 /*
1412 * Hypervisor uses this for application faults while it executes.
1413 * We get here for two reasons:
1414 * 1. Fault while reloading DS, ES, FS or GS
1415 * 2. Fault while executing IRET
1416 * Category 1 we do not need to fix up as Xen has already reloaded all segment
1417 * registers that could be reloaded and zeroed the others.
1418 * Category 2 we fix up by killing the current process. We cannot use the
1419 * normal Linux return path in this case because if we use the IRET hypercall
1420 * to pop the stack frame we end up in an infinite loop of failsafe callbacks.
1421 * We distinguish between categories by comparing each saved segment register
1422 * with its current contents: any discrepancy means we in category 1.
1423 */
1424 ENTRY(xen_failsafe_callback)
1425 INTR_FRAME 1 (6*8)
1426 /*CFI_REL_OFFSET gs,GS*/
1427 /*CFI_REL_OFFSET fs,FS*/
1428 /*CFI_REL_OFFSET es,ES*/
1429 /*CFI_REL_OFFSET ds,DS*/
1430 CFI_REL_OFFSET r11,8
1431 CFI_REL_OFFSET rcx,0
1432 movw %ds,%cx
1433 cmpw %cx,0x10(%rsp)
1434 CFI_REMEMBER_STATE
1435 jne 1f
1436 movw %es,%cx
1437 cmpw %cx,0x18(%rsp)
1438 jne 1f
1439 movw %fs,%cx
1440 cmpw %cx,0x20(%rsp)
1441 jne 1f
1442 movw %gs,%cx
1443 cmpw %cx,0x28(%rsp)
1444 jne 1f
1445 /* All segments match their saved values => Category 2 (Bad IRET). */
1446 movq (%rsp),%rcx
1447 CFI_RESTORE rcx
1448 movq 8(%rsp),%r11
1449 CFI_RESTORE r11
1450 addq $0x30,%rsp
1451 CFI_ADJUST_CFA_OFFSET -0x30
1452 pushq_cfi $0 /* RIP */
1453 pushq_cfi %r11
1454 pushq_cfi %rcx
1455 jmp general_protection
1456 CFI_RESTORE_STATE
1457 1: /* Segment mismatch => Category 1 (Bad segment). Retry the IRET. */
1458 movq (%rsp),%rcx
1459 CFI_RESTORE rcx
1460 movq 8(%rsp),%r11
1461 CFI_RESTORE r11
1462 addq $0x30,%rsp
1463 CFI_ADJUST_CFA_OFFSET -0x30
1464 pushq_cfi $-1 /* orig_ax = -1 => not a system call */
1465 SAVE_ALL
1466 jmp error_exit
1467 CFI_ENDPROC
1468 END(xen_failsafe_callback)
1470 apicinterrupt3 HYPERVISOR_CALLBACK_VECTOR \
1471 xen_hvm_callback_vector xen_evtchn_do_upcall
1473 #endif /* CONFIG_XEN */
1475 #if IS_ENABLED(CONFIG_HYPERV)
1476 apicinterrupt3 HYPERVISOR_CALLBACK_VECTOR \
1477 hyperv_callback_vector hyperv_vector_handler
1478 #endif /* CONFIG_HYPERV */
1480 /*
1481 * Some functions should be protected against kprobes
1482 */
1483 .pushsection .kprobes.text, "ax"
1485 paranoidzeroentry_ist debug do_debug DEBUG_STACK
1486 paranoidzeroentry_ist int3 do_int3 DEBUG_STACK
1487 paranoiderrorentry stack_segment do_stack_segment
1488 #ifdef CONFIG_XEN
1489 zeroentry xen_debug do_debug
1490 zeroentry xen_int3 do_int3
1491 errorentry xen_stack_segment do_stack_segment
1492 #endif
1493 errorentry general_protection do_general_protection
1494 trace_errorentry page_fault do_page_fault
1495 #ifdef CONFIG_KVM_GUEST
1496 errorentry async_page_fault do_async_page_fault
1497 #endif
1498 #ifdef CONFIG_X86_MCE
1499 paranoidzeroentry machine_check *machine_check_vector(%rip)
1500 #endif
1502 /*
1503 * "Paranoid" exit path from exception stack.
1504 * Paranoid because this is used by NMIs and cannot take
1505 * any kernel state for granted.
1506 * We don't do kernel preemption checks here, because only
1507 * NMI should be common and it does not enable IRQs and
1508 * cannot get reschedule ticks.
1509 *
1510 * "trace" is 0 for the NMI handler only, because irq-tracing
1511 * is fundamentally NMI-unsafe. (we cannot change the soft and
1512 * hard flags at once, atomically)
1513 */
1515 /* ebx: no swapgs flag */
1516 ENTRY(paranoid_exit)
1517 DEFAULT_FRAME
1518 DISABLE_INTERRUPTS(CLBR_NONE)
1519 TRACE_IRQS_OFF_DEBUG
1520 testl %ebx,%ebx /* swapgs needed? */
1521 jnz paranoid_restore
1522 testl $3,CS(%rsp)
1523 jnz paranoid_userspace
1524 paranoid_swapgs:
1525 TRACE_IRQS_IRETQ 0
1526 SWAPGS_UNSAFE_STACK
1527 RESTORE_ALL 8
1528 jmp irq_return
1529 paranoid_restore:
1530 TRACE_IRQS_IRETQ_DEBUG 0
1531 RESTORE_ALL 8
1532 jmp irq_return
1533 paranoid_userspace:
1534 GET_THREAD_INFO(%rcx)
1535 movl TI_flags(%rcx),%ebx
1536 andl $_TIF_WORK_MASK,%ebx
1537 jz paranoid_swapgs
1538 movq %rsp,%rdi /* &pt_regs */
1539 call sync_regs
1540 movq %rax,%rsp /* switch stack for scheduling */
1541 testl $_TIF_NEED_RESCHED,%ebx
1542 jnz paranoid_schedule
1543 movl %ebx,%edx /* arg3: thread flags */
1544 TRACE_IRQS_ON
1545 ENABLE_INTERRUPTS(CLBR_NONE)
1546 xorl %esi,%esi /* arg2: oldset */
1547 movq %rsp,%rdi /* arg1: &pt_regs */
1548 call do_notify_resume
1549 DISABLE_INTERRUPTS(CLBR_NONE)
1550 TRACE_IRQS_OFF
1551 jmp paranoid_userspace
1552 paranoid_schedule:
1553 TRACE_IRQS_ON
1554 ENABLE_INTERRUPTS(CLBR_ANY)
1555 SCHEDULE_USER
1556 DISABLE_INTERRUPTS(CLBR_ANY)
1557 TRACE_IRQS_OFF
1558 jmp paranoid_userspace
1559 CFI_ENDPROC
1560 END(paranoid_exit)
1562 /*
1563 * Exception entry point. This expects an error code/orig_rax on the stack.
1564 * returns in "no swapgs flag" in %ebx.
1565 */
1566 ENTRY(error_entry)
1567 XCPT_FRAME
1568 CFI_ADJUST_CFA_OFFSET 15*8
1569 /* oldrax contains error code */
1570 cld
1571 movq_cfi rdi, RDI+8
1572 movq_cfi rsi, RSI+8
1573 movq_cfi rdx, RDX+8
1574 movq_cfi rcx, RCX+8
1575 movq_cfi rax, RAX+8
1576 movq_cfi r8, R8+8
1577 movq_cfi r9, R9+8
1578 movq_cfi r10, R10+8
1579 movq_cfi r11, R11+8
1580 movq_cfi rbx, RBX+8
1581 movq_cfi rbp, RBP+8
1582 movq_cfi r12, R12+8
1583 movq_cfi r13, R13+8
1584 movq_cfi r14, R14+8
1585 movq_cfi r15, R15+8
1586 xorl %ebx,%ebx
1587 testl $3,CS+8(%rsp)
1588 je error_kernelspace
1589 error_swapgs:
1590 SWAPGS
1591 error_sti:
1592 TRACE_IRQS_OFF
1593 ret
1595 /*
1596 * There are two places in the kernel that can potentially fault with
1597 * usergs. Handle them here. The exception handlers after iret run with
1598 * kernel gs again, so don't set the user space flag. B stepping K8s
1599 * sometimes report an truncated RIP for IRET exceptions returning to
1600 * compat mode. Check for these here too.
1601 */
1602 error_kernelspace:
1603 incl %ebx
1604 leaq irq_return(%rip),%rcx
1605 cmpq %rcx,RIP+8(%rsp)
1606 je error_swapgs
1607 movl %ecx,%eax /* zero extend */
1608 cmpq %rax,RIP+8(%rsp)
1609 je bstep_iret
1610 cmpq $gs_change,RIP+8(%rsp)
1611 je error_swapgs
1612 jmp error_sti
1614 bstep_iret:
1615 /* Fix truncated RIP */
1616 movq %rcx,RIP+8(%rsp)
1617 jmp error_swapgs
1618 CFI_ENDPROC
1619 END(error_entry)
1622 /* ebx: no swapgs flag (1: don't need swapgs, 0: need it) */
1623 ENTRY(error_exit)
1624 DEFAULT_FRAME
1625 movl %ebx,%eax
1626 RESTORE_REST
1627 DISABLE_INTERRUPTS(CLBR_NONE)
1628 TRACE_IRQS_OFF
1629 GET_THREAD_INFO(%rcx)
1630 testl %eax,%eax
1631 jne retint_kernel
1632 LOCKDEP_SYS_EXIT_IRQ
1633 movl TI_flags(%rcx),%edx
1634 movl $_TIF_WORK_MASK,%edi
1635 andl %edi,%edx
1636 jnz retint_careful
1637 jmp retint_swapgs
1638 CFI_ENDPROC
1639 END(error_exit)
1641 /*
1642 * Test if a given stack is an NMI stack or not.
1643 */
1644 .macro test_in_nmi reg stack nmi_ret normal_ret
1645 cmpq %\reg, \stack
1646 ja \normal_ret
1647 subq $EXCEPTION_STKSZ, %\reg
1648 cmpq %\reg, \stack
1649 jb \normal_ret
1650 jmp \nmi_ret
1651 .endm
1653 /* runs on exception stack */
1654 ENTRY(nmi)
1655 INTR_FRAME
1656 PARAVIRT_ADJUST_EXCEPTION_FRAME
1657 /*
1658 * We allow breakpoints in NMIs. If a breakpoint occurs, then
1659 * the iretq it performs will take us out of NMI context.
1660 * This means that we can have nested NMIs where the next
1661 * NMI is using the top of the stack of the previous NMI. We
1662 * can't let it execute because the nested NMI will corrupt the
1663 * stack of the previous NMI. NMI handlers are not re-entrant
1664 * anyway.
1665 *
1666 * To handle this case we do the following:
1667 * Check the a special location on the stack that contains
1668 * a variable that is set when NMIs are executing.
1669 * The interrupted task's stack is also checked to see if it
1670 * is an NMI stack.
1671 * If the variable is not set and the stack is not the NMI
1672 * stack then:
1673 * o Set the special variable on the stack
1674 * o Copy the interrupt frame into a "saved" location on the stack
1675 * o Copy the interrupt frame into a "copy" location on the stack
1676 * o Continue processing the NMI
1677 * If the variable is set or the previous stack is the NMI stack:
1678 * o Modify the "copy" location to jump to the repeate_nmi
1679 * o return back to the first NMI
1680 *
1681 * Now on exit of the first NMI, we first clear the stack variable
1682 * The NMI stack will tell any nested NMIs at that point that it is
1683 * nested. Then we pop the stack normally with iret, and if there was
1684 * a nested NMI that updated the copy interrupt stack frame, a
1685 * jump will be made to the repeat_nmi code that will handle the second
1686 * NMI.
1687 */
1689 /* Use %rdx as out temp variable throughout */
1690 pushq_cfi %rdx
1691 CFI_REL_OFFSET rdx, 0
1693 /*
1694 * If %cs was not the kernel segment, then the NMI triggered in user
1695 * space, which means it is definitely not nested.
1696 */
1697 cmpl $__KERNEL_CS, 16(%rsp)
1698 jne first_nmi
1700 /*
1701 * Check the special variable on the stack to see if NMIs are
1702 * executing.
1703 */
1704 cmpl $1, -8(%rsp)
1705 je nested_nmi
1707 /*
1708 * Now test if the previous stack was an NMI stack.
1709 * We need the double check. We check the NMI stack to satisfy the
1710 * race when the first NMI clears the variable before returning.
1711 * We check the variable because the first NMI could be in a
1712 * breakpoint routine using a breakpoint stack.
1713 */
1714 lea 6*8(%rsp), %rdx
1715 test_in_nmi rdx, 4*8(%rsp), nested_nmi, first_nmi
1716 CFI_REMEMBER_STATE
1718 nested_nmi:
1719 /*
1720 * Do nothing if we interrupted the fixup in repeat_nmi.
1721 * It's about to repeat the NMI handler, so we are fine
1722 * with ignoring this one.
1723 */
1724 movq $repeat_nmi, %rdx
1725 cmpq 8(%rsp), %rdx
1726 ja 1f
1727 movq $end_repeat_nmi, %rdx
1728 cmpq 8(%rsp), %rdx
1729 ja nested_nmi_out
1731 1:
1732 /* Set up the interrupted NMIs stack to jump to repeat_nmi */
1733 leaq -1*8(%rsp), %rdx
1734 movq %rdx, %rsp
1735 CFI_ADJUST_CFA_OFFSET 1*8
1736 leaq -10*8(%rsp), %rdx
1737 pushq_cfi $__KERNEL_DS
1738 pushq_cfi %rdx
1739 pushfq_cfi
1740 pushq_cfi $__KERNEL_CS
1741 pushq_cfi $repeat_nmi
1743 /* Put stack back */
1744 addq $(6*8), %rsp
1745 CFI_ADJUST_CFA_OFFSET -6*8
1747 nested_nmi_out:
1748 popq_cfi %rdx
1749 CFI_RESTORE rdx
1751 /* No need to check faults here */
1752 INTERRUPT_RETURN
1754 CFI_RESTORE_STATE
1755 first_nmi:
1756 /*
1757 * Because nested NMIs will use the pushed location that we
1758 * stored in rdx, we must keep that space available.
1759 * Here's what our stack frame will look like:
1760 * +-------------------------+
1761 * | original SS |
1762 * | original Return RSP |
1763 * | original RFLAGS |
1764 * | original CS |
1765 * | original RIP |
1766 * +-------------------------+
1767 * | temp storage for rdx |
1768 * +-------------------------+
1769 * | NMI executing variable |
1770 * +-------------------------+
1771 * | copied SS |
1772 * | copied Return RSP |
1773 * | copied RFLAGS |
1774 * | copied CS |
1775 * | copied RIP |
1776 * +-------------------------+
1777 * | Saved SS |
1778 * | Saved Return RSP |
1779 * | Saved RFLAGS |
1780 * | Saved CS |
1781 * | Saved RIP |
1782 * +-------------------------+
1783 * | pt_regs |
1784 * +-------------------------+
1785 *
1786 * The saved stack frame is used to fix up the copied stack frame
1787 * that a nested NMI may change to make the interrupted NMI iret jump
1788 * to the repeat_nmi. The original stack frame and the temp storage
1789 * is also used by nested NMIs and can not be trusted on exit.
1790 */
1791 /* Do not pop rdx, nested NMIs will corrupt that part of the stack */
1792 movq (%rsp), %rdx
1793 CFI_RESTORE rdx
1795 /* Set the NMI executing variable on the stack. */
1796 pushq_cfi $1
1798 /*
1799 * Leave room for the "copied" frame
1800 */
1801 subq $(5*8), %rsp
1802 CFI_ADJUST_CFA_OFFSET 5*8
1804 /* Copy the stack frame to the Saved frame */
1805 .rept 5
1806 pushq_cfi 11*8(%rsp)
1807 .endr
1808 CFI_DEF_CFA_OFFSET SS+8-RIP
1810 /* Everything up to here is safe from nested NMIs */
1812 /*
1813 * If there was a nested NMI, the first NMI's iret will return
1814 * here. But NMIs are still enabled and we can take another
1815 * nested NMI. The nested NMI checks the interrupted RIP to see
1816 * if it is between repeat_nmi and end_repeat_nmi, and if so
1817 * it will just return, as we are about to repeat an NMI anyway.
1818 * This makes it safe to copy to the stack frame that a nested
1819 * NMI will update.
1820 */
1821 repeat_nmi:
1822 /*
1823 * Update the stack variable to say we are still in NMI (the update
1824 * is benign for the non-repeat case, where 1 was pushed just above
1825 * to this very stack slot).
1826 */
1827 movq $1, 10*8(%rsp)
1829 /* Make another copy, this one may be modified by nested NMIs */
1830 addq $(10*8), %rsp
1831 CFI_ADJUST_CFA_OFFSET -10*8
1832 .rept 5
1833 pushq_cfi -6*8(%rsp)
1834 .endr
1835 subq $(5*8), %rsp
1836 CFI_DEF_CFA_OFFSET SS+8-RIP
1837 end_repeat_nmi:
1839 /*
1840 * Everything below this point can be preempted by a nested
1841 * NMI if the first NMI took an exception and reset our iret stack
1842 * so that we repeat another NMI.
1843 */
1844 pushq_cfi $-1 /* ORIG_RAX: no syscall to restart */
1845 subq $ORIG_RAX-R15, %rsp
1846 CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15
1847 /*
1848 * Use save_paranoid to handle SWAPGS, but no need to use paranoid_exit
1849 * as we should not be calling schedule in NMI context.
1850 * Even with normal interrupts enabled. An NMI should not be
1851 * setting NEED_RESCHED or anything that normal interrupts and
1852 * exceptions might do.
1853 */
1854 call save_paranoid
1855 DEFAULT_FRAME 0
1857 /*
1858 * Save off the CR2 register. If we take a page fault in the NMI then
1859 * it could corrupt the CR2 value. If the NMI preempts a page fault
1860 * handler before it was able to read the CR2 register, and then the
1861 * NMI itself takes a page fault, the page fault that was preempted
1862 * will read the information from the NMI page fault and not the
1863 * origin fault. Save it off and restore it if it changes.
1864 * Use the r12 callee-saved register.
1865 */
1866 movq %cr2, %r12
1868 /* paranoidentry do_nmi, 0; without TRACE_IRQS_OFF */
1869 movq %rsp,%rdi
1870 movq $-1,%rsi
1871 call do_nmi
1873 /* Did the NMI take a page fault? Restore cr2 if it did */
1874 movq %cr2, %rcx
1875 cmpq %rcx, %r12
1876 je 1f
1877 movq %r12, %cr2
1878 1:
1880 testl %ebx,%ebx /* swapgs needed? */
1881 jnz nmi_restore
1882 nmi_swapgs:
1883 SWAPGS_UNSAFE_STACK
1884 nmi_restore:
1885 /* Pop the extra iret frame at once */
1886 RESTORE_ALL 6*8
1888 /* Clear the NMI executing stack variable */
1889 movq $0, 5*8(%rsp)
1890 jmp irq_return
1891 CFI_ENDPROC
1892 END(nmi)
1894 ENTRY(ignore_sysret)
1895 CFI_STARTPROC
1896 mov $-ENOSYS,%eax
1897 sysret
1898 CFI_ENDPROC
1899 END(ignore_sysret)
1901 /*
1902 * End of kprobes section
1903 */
1904 .popsection