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-rw-r--r--arch/x86/kernel/signal.c898
1 files changed, 898 insertions, 0 deletions
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
new file mode 100644
index 000000000000..7cdcd16885ed
--- /dev/null
+++ b/arch/x86/kernel/signal.c
@@ -0,0 +1,898 @@
1/*
2 * Copyright (C) 1991, 1992 Linus Torvalds
3 * Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
4 *
5 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
6 * 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
7 * 2000-2002 x86-64 support by Andi Kleen
8 */
9
10#include <linux/sched.h>
11#include <linux/mm.h>
12#include <linux/smp.h>
13#include <linux/kernel.h>
14#include <linux/signal.h>
15#include <linux/errno.h>
16#include <linux/wait.h>
17#include <linux/ptrace.h>
18#include <linux/tracehook.h>
19#include <linux/unistd.h>
20#include <linux/stddef.h>
21#include <linux/personality.h>
22#include <linux/uaccess.h>
23
24#include <asm/processor.h>
25#include <asm/ucontext.h>
26#include <asm/i387.h>
27#include <asm/vdso.h>
28
29#ifdef CONFIG_X86_64
30#include <asm/proto.h>
31#include <asm/ia32_unistd.h>
32#include <asm/mce.h>
33#endif /* CONFIG_X86_64 */
34
35#include <asm/syscall.h>
36#include <asm/syscalls.h>
37
38#include <asm/sigframe.h>
39
40#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
41
42#define __FIX_EFLAGS (X86_EFLAGS_AC | X86_EFLAGS_OF | \
43 X86_EFLAGS_DF | X86_EFLAGS_TF | X86_EFLAGS_SF | \
44 X86_EFLAGS_ZF | X86_EFLAGS_AF | X86_EFLAGS_PF | \
45 X86_EFLAGS_CF)
46
47#ifdef CONFIG_X86_32
48# define FIX_EFLAGS (__FIX_EFLAGS | X86_EFLAGS_RF)
49#else
50# define FIX_EFLAGS __FIX_EFLAGS
51#endif
52
53#define COPY(x) do { \
54 get_user_ex(regs->x, &sc->x); \
55} while (0)
56
57#define GET_SEG(seg) ({ \
58 unsigned short tmp; \
59 get_user_ex(tmp, &sc->seg); \
60 tmp; \
61})
62
63#define COPY_SEG(seg) do { \
64 regs->seg = GET_SEG(seg); \
65} while (0)
66
67#define COPY_SEG_CPL3(seg) do { \
68 regs->seg = GET_SEG(seg) | 3; \
69} while (0)
70
71static int
72restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
73 unsigned long *pax)
74{
75 void __user *buf;
76 unsigned int tmpflags;
77 unsigned int err = 0;
78
79 /* Always make any pending restarted system calls return -EINTR */
80 current_thread_info()->restart_block.fn = do_no_restart_syscall;
81
82 get_user_try {
83
84#ifdef CONFIG_X86_32
85 set_user_gs(regs, GET_SEG(gs));
86 COPY_SEG(fs);
87 COPY_SEG(es);
88 COPY_SEG(ds);
89#endif /* CONFIG_X86_32 */
90
91 COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
92 COPY(dx); COPY(cx); COPY(ip);
93
94#ifdef CONFIG_X86_64
95 COPY(r8);
96 COPY(r9);
97 COPY(r10);
98 COPY(r11);
99 COPY(r12);
100 COPY(r13);
101 COPY(r14);
102 COPY(r15);
103#endif /* CONFIG_X86_64 */
104
105#ifdef CONFIG_X86_32
106 COPY_SEG_CPL3(cs);
107 COPY_SEG_CPL3(ss);
108#else /* !CONFIG_X86_32 */
109 /* Kernel saves and restores only the CS segment register on signals,
110 * which is the bare minimum needed to allow mixed 32/64-bit code.
111 * App's signal handler can save/restore other segments if needed. */
112 COPY_SEG_CPL3(cs);
113#endif /* CONFIG_X86_32 */
114
115 get_user_ex(tmpflags, &sc->flags);
116 regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
117 regs->orig_ax = -1; /* disable syscall checks */
118
119 get_user_ex(buf, &sc->fpstate);
120 err |= restore_i387_xstate(buf);
121
122 get_user_ex(*pax, &sc->ax);
123 } get_user_catch(err);
124
125 return err;
126}
127
128static int
129setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
130 struct pt_regs *regs, unsigned long mask)
131{
132 int err = 0;
133
134 put_user_try {
135
136#ifdef CONFIG_X86_32
137 put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs);
138 put_user_ex(regs->fs, (unsigned int __user *)&sc->fs);
139 put_user_ex(regs->es, (unsigned int __user *)&sc->es);
140 put_user_ex(regs->ds, (unsigned int __user *)&sc->ds);
141#endif /* CONFIG_X86_32 */
142
143 put_user_ex(regs->di, &sc->di);
144 put_user_ex(regs->si, &sc->si);
145 put_user_ex(regs->bp, &sc->bp);
146 put_user_ex(regs->sp, &sc->sp);
147 put_user_ex(regs->bx, &sc->bx);
148 put_user_ex(regs->dx, &sc->dx);
149 put_user_ex(regs->cx, &sc->cx);
150 put_user_ex(regs->ax, &sc->ax);
151#ifdef CONFIG_X86_64
152 put_user_ex(regs->r8, &sc->r8);
153 put_user_ex(regs->r9, &sc->r9);
154 put_user_ex(regs->r10, &sc->r10);
155 put_user_ex(regs->r11, &sc->r11);
156 put_user_ex(regs->r12, &sc->r12);
157 put_user_ex(regs->r13, &sc->r13);
158 put_user_ex(regs->r14, &sc->r14);
159 put_user_ex(regs->r15, &sc->r15);
160#endif /* CONFIG_X86_64 */
161
162 put_user_ex(current->thread.trap_no, &sc->trapno);
163 put_user_ex(current->thread.error_code, &sc->err);
164 put_user_ex(regs->ip, &sc->ip);
165#ifdef CONFIG_X86_32
166 put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
167 put_user_ex(regs->flags, &sc->flags);
168 put_user_ex(regs->sp, &sc->sp_at_signal);
169 put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
170#else /* !CONFIG_X86_32 */
171 put_user_ex(regs->flags, &sc->flags);
172 put_user_ex(regs->cs, &sc->cs);
173 put_user_ex(0, &sc->gs);
174 put_user_ex(0, &sc->fs);
175#endif /* CONFIG_X86_32 */
176
177 put_user_ex(fpstate, &sc->fpstate);
178
179 /* non-iBCS2 extensions.. */
180 put_user_ex(mask, &sc->oldmask);
181 put_user_ex(current->thread.cr2, &sc->cr2);
182 } put_user_catch(err);
183
184 return err;
185}
186
187/*
188 * Set up a signal frame.
189 */
190#ifdef CONFIG_X86_32
191static const struct {
192 u16 poplmovl;
193 u32 val;
194 u16 int80;
195} __attribute__((packed)) retcode = {
196 0xb858, /* popl %eax; movl $..., %eax */
197 __NR_sigreturn,
198 0x80cd, /* int $0x80 */
199};
200
201static const struct {
202 u8 movl;
203 u32 val;
204 u16 int80;
205 u8 pad;
206} __attribute__((packed)) rt_retcode = {
207 0xb8, /* movl $..., %eax */
208 __NR_rt_sigreturn,
209 0x80cd, /* int $0x80 */
210 0
211};
212
213/*
214 * Determine which stack to use..
215 */
216static inline void __user *
217get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
218 void **fpstate)
219{
220 unsigned long sp;
221
222 /* Default to using normal stack */
223 sp = regs->sp;
224
225 /*
226 * If we are on the alternate signal stack and would overflow it, don't.
227 * Return an always-bogus address instead so we will die with SIGSEGV.
228 */
229 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
230 return (void __user *) -1L;
231
232 /* This is the X/Open sanctioned signal stack switching. */
233 if (ka->sa.sa_flags & SA_ONSTACK) {
234 if (sas_ss_flags(sp) == 0)
235 sp = current->sas_ss_sp + current->sas_ss_size;
236 } else {
237 /* This is the legacy signal stack switching. */
238 if ((regs->ss & 0xffff) != __USER_DS &&
239 !(ka->sa.sa_flags & SA_RESTORER) &&
240 ka->sa.sa_restorer)
241 sp = (unsigned long) ka->sa.sa_restorer;
242 }
243
244 if (used_math()) {
245 sp = sp - sig_xstate_size;
246 *fpstate = (struct _fpstate *) sp;
247 if (save_i387_xstate(*fpstate) < 0)
248 return (void __user *)-1L;
249 }
250
251 sp -= frame_size;
252 /*
253 * Align the stack pointer according to the i386 ABI,
254 * i.e. so that on function entry ((sp + 4) & 15) == 0.
255 */
256 sp = ((sp + 4) & -16ul) - 4;
257
258 return (void __user *) sp;
259}
260
261static int
262__setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
263 struct pt_regs *regs)
264{
265 struct sigframe __user *frame;
266 void __user *restorer;
267 int err = 0;
268 void __user *fpstate = NULL;
269
270 frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
271
272 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
273 return -EFAULT;
274
275 if (__put_user(sig, &frame->sig))
276 return -EFAULT;
277
278 if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
279 return -EFAULT;
280
281 if (_NSIG_WORDS > 1) {
282 if (__copy_to_user(&frame->extramask, &set->sig[1],
283 sizeof(frame->extramask)))
284 return -EFAULT;
285 }
286
287 if (current->mm->context.vdso)
288 restorer = VDSO32_SYMBOL(current->mm->context.vdso, sigreturn);
289 else
290 restorer = &frame->retcode;
291 if (ka->sa.sa_flags & SA_RESTORER)
292 restorer = ka->sa.sa_restorer;
293
294 /* Set up to return from userspace. */
295 err |= __put_user(restorer, &frame->pretcode);
296
297 /*
298 * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
299 *
300 * WE DO NOT USE IT ANY MORE! It's only left here for historical
301 * reasons and because gdb uses it as a signature to notice
302 * signal handler stack frames.
303 */
304 err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode);
305
306 if (err)
307 return -EFAULT;
308
309 /* Set up registers for signal handler */
310 regs->sp = (unsigned long)frame;
311 regs->ip = (unsigned long)ka->sa.sa_handler;
312 regs->ax = (unsigned long)sig;
313 regs->dx = 0;
314 regs->cx = 0;
315
316 regs->ds = __USER_DS;
317 regs->es = __USER_DS;
318 regs->ss = __USER_DS;
319 regs->cs = __USER_CS;
320
321 return 0;
322}
323
324static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
325 sigset_t *set, struct pt_regs *regs)
326{
327 struct rt_sigframe __user *frame;
328 void __user *restorer;
329 int err = 0;
330 void __user *fpstate = NULL;
331
332 frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
333
334 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
335 return -EFAULT;
336
337 put_user_try {
338 put_user_ex(sig, &frame->sig);
339 put_user_ex(&frame->info, &frame->pinfo);
340 put_user_ex(&frame->uc, &frame->puc);
341 err |= copy_siginfo_to_user(&frame->info, info);
342
343 /* Create the ucontext. */
344 if (cpu_has_xsave)
345 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
346 else
347 put_user_ex(0, &frame->uc.uc_flags);
348 put_user_ex(0, &frame->uc.uc_link);
349 put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
350 put_user_ex(sas_ss_flags(regs->sp),
351 &frame->uc.uc_stack.ss_flags);
352 put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
353 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
354 regs, set->sig[0]);
355 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
356
357 /* Set up to return from userspace. */
358 restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn);
359 if (ka->sa.sa_flags & SA_RESTORER)
360 restorer = ka->sa.sa_restorer;
361 put_user_ex(restorer, &frame->pretcode);
362
363 /*
364 * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
365 *
366 * WE DO NOT USE IT ANY MORE! It's only left here for historical
367 * reasons and because gdb uses it as a signature to notice
368 * signal handler stack frames.
369 */
370 put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
371 } put_user_catch(err);
372
373 if (err)
374 return -EFAULT;
375
376 /* Set up registers for signal handler */
377 regs->sp = (unsigned long)frame;
378 regs->ip = (unsigned long)ka->sa.sa_handler;
379 regs->ax = (unsigned long)sig;
380 regs->dx = (unsigned long)&frame->info;
381 regs->cx = (unsigned long)&frame->uc;
382
383 regs->ds = __USER_DS;
384 regs->es = __USER_DS;
385 regs->ss = __USER_DS;
386 regs->cs = __USER_CS;
387
388 return 0;
389}
390#else /* !CONFIG_X86_32 */
391/*
392 * Determine which stack to use..
393 */
394static void __user *
395get_stack(struct k_sigaction *ka, unsigned long sp, unsigned long size)
396{
397 /* Default to using normal stack - redzone*/
398 sp -= 128;
399
400 /* This is the X/Open sanctioned signal stack switching. */
401 if (ka->sa.sa_flags & SA_ONSTACK) {
402 if (sas_ss_flags(sp) == 0)
403 sp = current->sas_ss_sp + current->sas_ss_size;
404 }
405
406 return (void __user *)round_down(sp - size, 64);
407}
408
409static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
410 sigset_t *set, struct pt_regs *regs)
411{
412 struct rt_sigframe __user *frame;
413 void __user *fp = NULL;
414 int err = 0;
415 struct task_struct *me = current;
416
417 if (used_math()) {
418 fp = get_stack(ka, regs->sp, sig_xstate_size);
419 frame = (void __user *)round_down(
420 (unsigned long)fp - sizeof(struct rt_sigframe), 16) - 8;
421
422 if (save_i387_xstate(fp) < 0)
423 return -EFAULT;
424 } else
425 frame = get_stack(ka, regs->sp, sizeof(struct rt_sigframe)) - 8;
426
427 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
428 return -EFAULT;
429
430 if (ka->sa.sa_flags & SA_SIGINFO) {
431 if (copy_siginfo_to_user(&frame->info, info))
432 return -EFAULT;
433 }
434
435 put_user_try {
436 /* Create the ucontext. */
437 if (cpu_has_xsave)
438 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
439 else
440 put_user_ex(0, &frame->uc.uc_flags);
441 put_user_ex(0, &frame->uc.uc_link);
442 put_user_ex(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
443 put_user_ex(sas_ss_flags(regs->sp),
444 &frame->uc.uc_stack.ss_flags);
445 put_user_ex(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
446 err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
447 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
448
449 /* Set up to return from userspace. If provided, use a stub
450 already in userspace. */
451 /* x86-64 should always use SA_RESTORER. */
452 if (ka->sa.sa_flags & SA_RESTORER) {
453 put_user_ex(ka->sa.sa_restorer, &frame->pretcode);
454 } else {
455 /* could use a vstub here */
456 err |= -EFAULT;
457 }
458 } put_user_catch(err);
459
460 if (err)
461 return -EFAULT;
462
463 /* Set up registers for signal handler */
464 regs->di = sig;
465 /* In case the signal handler was declared without prototypes */
466 regs->ax = 0;
467
468 /* This also works for non SA_SIGINFO handlers because they expect the
469 next argument after the signal number on the stack. */
470 regs->si = (unsigned long)&frame->info;
471 regs->dx = (unsigned long)&frame->uc;
472 regs->ip = (unsigned long) ka->sa.sa_handler;
473
474 regs->sp = (unsigned long)frame;
475
476 /* Set up the CS register to run signal handlers in 64-bit mode,
477 even if the handler happens to be interrupting 32-bit code. */
478 regs->cs = __USER_CS;
479
480 return 0;
481}
482#endif /* CONFIG_X86_32 */
483
484#ifdef CONFIG_X86_32
485/*
486 * Atomically swap in the new signal mask, and wait for a signal.
487 */
488asmlinkage int
489sys_sigsuspend(int history0, int history1, old_sigset_t mask)
490{
491 mask &= _BLOCKABLE;
492 spin_lock_irq(&current->sighand->siglock);
493 current->saved_sigmask = current->blocked;
494 siginitset(&current->blocked, mask);
495 recalc_sigpending();
496 spin_unlock_irq(&current->sighand->siglock);
497
498 current->state = TASK_INTERRUPTIBLE;
499 schedule();
500 set_restore_sigmask();
501
502 return -ERESTARTNOHAND;
503}
504
505asmlinkage int
506sys_sigaction(int sig, const struct old_sigaction __user *act,
507 struct old_sigaction __user *oact)
508{
509 struct k_sigaction new_ka, old_ka;
510 int ret = 0;
511
512 if (act) {
513 old_sigset_t mask;
514
515 if (!access_ok(VERIFY_READ, act, sizeof(*act)))
516 return -EFAULT;
517
518 get_user_try {
519 get_user_ex(new_ka.sa.sa_handler, &act->sa_handler);
520 get_user_ex(new_ka.sa.sa_flags, &act->sa_flags);
521 get_user_ex(mask, &act->sa_mask);
522 get_user_ex(new_ka.sa.sa_restorer, &act->sa_restorer);
523 } get_user_catch(ret);
524
525 if (ret)
526 return -EFAULT;
527 siginitset(&new_ka.sa.sa_mask, mask);
528 }
529
530 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
531
532 if (!ret && oact) {
533 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
534 return -EFAULT;
535
536 put_user_try {
537 put_user_ex(old_ka.sa.sa_handler, &oact->sa_handler);
538 put_user_ex(old_ka.sa.sa_flags, &oact->sa_flags);
539 put_user_ex(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
540 put_user_ex(old_ka.sa.sa_restorer, &oact->sa_restorer);
541 } put_user_catch(ret);
542
543 if (ret)
544 return -EFAULT;
545 }
546
547 return ret;
548}
549#endif /* CONFIG_X86_32 */
550
551#ifdef CONFIG_X86_32
552int sys_sigaltstack(struct pt_regs *regs)
553{
554 const stack_t __user *uss = (const stack_t __user *)regs->bx;
555 stack_t __user *uoss = (stack_t __user *)regs->cx;
556
557 return do_sigaltstack(uss, uoss, regs->sp);
558}
559#else /* !CONFIG_X86_32 */
560asmlinkage long
561sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
562 struct pt_regs *regs)
563{
564 return do_sigaltstack(uss, uoss, regs->sp);
565}
566#endif /* CONFIG_X86_32 */
567
568/*
569 * Do a signal return; undo the signal stack.
570 */
571#ifdef CONFIG_X86_32
572unsigned long sys_sigreturn(struct pt_regs *regs)
573{
574 struct sigframe __user *frame;
575 unsigned long ax;
576 sigset_t set;
577
578 frame = (struct sigframe __user *)(regs->sp - 8);
579
580 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
581 goto badframe;
582 if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
583 && __copy_from_user(&set.sig[1], &frame->extramask,
584 sizeof(frame->extramask))))
585 goto badframe;
586
587 sigdelsetmask(&set, ~_BLOCKABLE);
588 spin_lock_irq(&current->sighand->siglock);
589 current->blocked = set;
590 recalc_sigpending();
591 spin_unlock_irq(&current->sighand->siglock);
592
593 if (restore_sigcontext(regs, &frame->sc, &ax))
594 goto badframe;
595 return ax;
596
597badframe:
598 signal_fault(regs, frame, "sigreturn");
599
600 return 0;
601}
602#endif /* CONFIG_X86_32 */
603
604long sys_rt_sigreturn(struct pt_regs *regs)
605{
606 struct rt_sigframe __user *frame;
607 unsigned long ax;
608 sigset_t set;
609
610 frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
611 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
612 goto badframe;
613 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
614 goto badframe;
615
616 sigdelsetmask(&set, ~_BLOCKABLE);
617 spin_lock_irq(&current->sighand->siglock);
618 current->blocked = set;
619 recalc_sigpending();
620 spin_unlock_irq(&current->sighand->siglock);
621
622 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
623 goto badframe;
624
625 if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
626 goto badframe;
627
628 return ax;
629
630badframe:
631 signal_fault(regs, frame, "rt_sigreturn");
632 return 0;
633}
634
635/*
636 * OK, we're invoking a handler:
637 */
638static int signr_convert(int sig)
639{
640#ifdef CONFIG_X86_32
641 struct thread_info *info = current_thread_info();
642
643 if (info->exec_domain && info->exec_domain->signal_invmap && sig < 32)
644 return info->exec_domain->signal_invmap[sig];
645#endif /* CONFIG_X86_32 */
646 return sig;
647}
648
649#ifdef CONFIG_X86_32
650
651#define is_ia32 1
652#define ia32_setup_frame __setup_frame
653#define ia32_setup_rt_frame __setup_rt_frame
654
655#else /* !CONFIG_X86_32 */
656
657#ifdef CONFIG_IA32_EMULATION
658#define is_ia32 test_thread_flag(TIF_IA32)
659#else /* !CONFIG_IA32_EMULATION */
660#define is_ia32 0
661#endif /* CONFIG_IA32_EMULATION */
662
663int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
664 sigset_t *set, struct pt_regs *regs);
665int ia32_setup_frame(int sig, struct k_sigaction *ka,
666 sigset_t *set, struct pt_regs *regs);
667
668#endif /* CONFIG_X86_32 */
669
670static int
671setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
672 sigset_t *set, struct pt_regs *regs)
673{
674 int usig = signr_convert(sig);
675 int ret;
676
677 /* Set up the stack frame */
678 if (is_ia32) {
679 if (ka->sa.sa_flags & SA_SIGINFO)
680 ret = ia32_setup_rt_frame(usig, ka, info, set, regs);
681 else
682 ret = ia32_setup_frame(usig, ka, set, regs);
683 } else
684 ret = __setup_rt_frame(sig, ka, info, set, regs);
685
686 if (ret) {
687 force_sigsegv(sig, current);
688 return -EFAULT;
689 }
690
691 return ret;
692}
693
694static int
695handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
696 sigset_t *oldset, struct pt_regs *regs)
697{
698 int ret;
699
700 /* Are we from a system call? */
701 if (syscall_get_nr(current, regs) >= 0) {
702 /* If so, check system call restarting.. */
703 switch (syscall_get_error(current, regs)) {
704 case -ERESTART_RESTARTBLOCK:
705 case -ERESTARTNOHAND:
706 regs->ax = -EINTR;
707 break;
708
709 case -ERESTARTSYS:
710 if (!(ka->sa.sa_flags & SA_RESTART)) {
711 regs->ax = -EINTR;
712 break;
713 }
714 /* fallthrough */
715 case -ERESTARTNOINTR:
716 regs->ax = regs->orig_ax;
717 regs->ip -= 2;
718 break;
719 }
720 }
721
722 /*
723 * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
724 * flag so that register information in the sigcontext is correct.
725 */
726 if (unlikely(regs->flags & X86_EFLAGS_TF) &&
727 likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
728 regs->flags &= ~X86_EFLAGS_TF;
729
730 ret = setup_rt_frame(sig, ka, info, oldset, regs);
731
732 if (ret)
733 return ret;
734
735#ifdef CONFIG_X86_64
736 /*
737 * This has nothing to do with segment registers,
738 * despite the name. This magic affects uaccess.h
739 * macros' behavior. Reset it to the normal setting.
740 */
741 set_fs(USER_DS);
742#endif
743
744 /*
745 * Clear the direction flag as per the ABI for function entry.
746 */
747 regs->flags &= ~X86_EFLAGS_DF;
748
749 /*
750 * Clear TF when entering the signal handler, but
751 * notify any tracer that was single-stepping it.
752 * The tracer may want to single-step inside the
753 * handler too.
754 */
755 regs->flags &= ~X86_EFLAGS_TF;
756
757 spin_lock_irq(&current->sighand->siglock);
758 sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
759 if (!(ka->sa.sa_flags & SA_NODEFER))
760 sigaddset(&current->blocked, sig);
761 recalc_sigpending();
762 spin_unlock_irq(&current->sighand->siglock);
763
764 tracehook_signal_handler(sig, info, ka, regs,
765 test_thread_flag(TIF_SINGLESTEP));
766
767 return 0;
768}
769
770#ifdef CONFIG_X86_32
771#define NR_restart_syscall __NR_restart_syscall
772#else /* !CONFIG_X86_32 */
773#define NR_restart_syscall \
774 test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall
775#endif /* CONFIG_X86_32 */
776
777/*
778 * Note that 'init' is a special process: it doesn't get signals it doesn't
779 * want to handle. Thus you cannot kill init even with a SIGKILL even by
780 * mistake.
781 */
782static void do_signal(struct pt_regs *regs)
783{
784 struct k_sigaction ka;
785 siginfo_t info;
786 int signr;
787 sigset_t *oldset;
788
789 /*
790 * We want the common case to go fast, which is why we may in certain
791 * cases get here from kernel mode. Just return without doing anything
792 * if so.
793 * X86_32: vm86 regs switched out by assembly code before reaching
794 * here, so testing against kernel CS suffices.
795 */
796 if (!user_mode(regs))
797 return;
798
799 if (current_thread_info()->status & TS_RESTORE_SIGMASK)
800 oldset = &current->saved_sigmask;
801 else
802 oldset = &current->blocked;
803
804 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
805 if (signr > 0) {
806 /*
807 * Re-enable any watchpoints before delivering the
808 * signal to user space. The processor register will
809 * have been cleared if the watchpoint triggered
810 * inside the kernel.
811 */
812 if (current->thread.debugreg7)
813 set_debugreg(current->thread.debugreg7, 7);
814
815 /* Whee! Actually deliver the signal. */
816 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
817 /*
818 * A signal was successfully delivered; the saved
819 * sigmask will have been stored in the signal frame,
820 * and will be restored by sigreturn, so we can simply
821 * clear the TS_RESTORE_SIGMASK flag.
822 */
823 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
824 }
825 return;
826 }
827
828 /* Did we come from a system call? */
829 if (syscall_get_nr(current, regs) >= 0) {
830 /* Restart the system call - no handlers present */
831 switch (syscall_get_error(current, regs)) {
832 case -ERESTARTNOHAND:
833 case -ERESTARTSYS:
834 case -ERESTARTNOINTR:
835 regs->ax = regs->orig_ax;
836 regs->ip -= 2;
837 break;
838
839 case -ERESTART_RESTARTBLOCK:
840 regs->ax = NR_restart_syscall;
841 regs->ip -= 2;
842 break;
843 }
844 }
845
846 /*
847 * If there's no signal to deliver, we just put the saved sigmask
848 * back.
849 */
850 if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
851 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
852 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
853 }
854}
855
856/*
857 * notification of userspace execution resumption
858 * - triggered by the TIF_WORK_MASK flags
859 */
860void
861do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
862{
863#if defined(CONFIG_X86_64) && defined(CONFIG_X86_MCE)
864 /* notify userspace of pending MCEs */
865 if (thread_info_flags & _TIF_MCE_NOTIFY)
866 mce_notify_user();
867#endif /* CONFIG_X86_64 && CONFIG_X86_MCE */
868
869 /* deal with pending signal delivery */
870 if (thread_info_flags & _TIF_SIGPENDING)
871 do_signal(regs);
872
873 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
874 clear_thread_flag(TIF_NOTIFY_RESUME);
875 tracehook_notify_resume(regs);
876 }
877
878#ifdef CONFIG_X86_32
879 clear_thread_flag(TIF_IRET);
880#endif /* CONFIG_X86_32 */
881}
882
883void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
884{
885 struct task_struct *me = current;
886
887 if (show_unhandled_signals && printk_ratelimit()) {
888 printk("%s"
889 "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
890 task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
891 me->comm, me->pid, where, frame,
892 regs->ip, regs->sp, regs->orig_ax);
893 print_vma_addr(" in ", regs->ip);
894 printk(KERN_CONT "\n");
895 }
896
897 force_sig(SIGSEGV, me);
898}
generated by cgit v1.2.2 (git 2.25.0) at 2025-09-17 22:26:42 -0400