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[mirror_ubuntu-zesty-kernel.git] / arch / x86 / kernel / signal.c
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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12 #include <linux/sched.h>
13 #include <linux/mm.h>
14 #include <linux/smp.h>
15 #include <linux/kernel.h>
16 #include <linux/errno.h>
17 #include <linux/wait.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 #include <linux/user-return-notifier.h>
24 #include <linux/uprobes.h>
25 #include <linux/context_tracking.h>
26
27 #include <asm/processor.h>
28 #include <asm/ucontext.h>
29 #include <asm/i387.h>
30 #include <asm/fpu-internal.h>
31 #include <asm/vdso.h>
32 #include <asm/mce.h>
33 #include <asm/sighandling.h>
34
35 #ifdef CONFIG_X86_64
36 #include <asm/proto.h>
37 #include <asm/ia32_unistd.h>
38 #include <asm/sys_ia32.h>
39 #endif /* CONFIG_X86_64 */
40
41 #include <asm/syscall.h>
42 #include <asm/syscalls.h>
43
44 #include <asm/sigframe.h>
45
46 #define COPY(x) do { \
47 get_user_ex(regs->x, &sc->x); \
48 } while (0)
49
50 #define GET_SEG(seg) ({ \
51 unsigned short tmp; \
52 get_user_ex(tmp, &sc->seg); \
53 tmp; \
54 })
55
56 #define COPY_SEG(seg) do { \
57 regs->seg = GET_SEG(seg); \
58 } while (0)
59
60 #define COPY_SEG_CPL3(seg) do { \
61 regs->seg = GET_SEG(seg) | 3; \
62 } while (0)
63
64 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
65 unsigned long *pax)
66 {
67 void __user *buf;
68 unsigned int tmpflags;
69 unsigned int err = 0;
70
71 /* Always make any pending restarted system calls return -EINTR */
72 current->restart_block.fn = do_no_restart_syscall;
73
74 get_user_try {
75
76 #ifdef CONFIG_X86_32
77 set_user_gs(regs, GET_SEG(gs));
78 COPY_SEG(fs);
79 COPY_SEG(es);
80 COPY_SEG(ds);
81 #endif /* CONFIG_X86_32 */
82
83 COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
84 COPY(dx); COPY(cx); COPY(ip);
85
86 #ifdef CONFIG_X86_64
87 COPY(r8);
88 COPY(r9);
89 COPY(r10);
90 COPY(r11);
91 COPY(r12);
92 COPY(r13);
93 COPY(r14);
94 COPY(r15);
95 #endif /* CONFIG_X86_64 */
96
97 #ifdef CONFIG_X86_32
98 COPY_SEG_CPL3(cs);
99 COPY_SEG_CPL3(ss);
100 #else /* !CONFIG_X86_32 */
101 /* Kernel saves and restores only the CS segment register on signals,
102 * which is the bare minimum needed to allow mixed 32/64-bit code.
103 * App's signal handler can save/restore other segments if needed. */
104 COPY_SEG_CPL3(cs);
105 #endif /* CONFIG_X86_32 */
106
107 get_user_ex(tmpflags, &sc->flags);
108 regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
109 regs->orig_ax = -1; /* disable syscall checks */
110
111 get_user_ex(buf, &sc->fpstate);
112
113 get_user_ex(*pax, &sc->ax);
114 } get_user_catch(err);
115
116 err |= restore_xstate_sig(buf, config_enabled(CONFIG_X86_32));
117
118 return err;
119 }
120
121 int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
122 struct pt_regs *regs, unsigned long mask)
123 {
124 int err = 0;
125
126 put_user_try {
127
128 #ifdef CONFIG_X86_32
129 put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs);
130 put_user_ex(regs->fs, (unsigned int __user *)&sc->fs);
131 put_user_ex(regs->es, (unsigned int __user *)&sc->es);
132 put_user_ex(regs->ds, (unsigned int __user *)&sc->ds);
133 #endif /* CONFIG_X86_32 */
134
135 put_user_ex(regs->di, &sc->di);
136 put_user_ex(regs->si, &sc->si);
137 put_user_ex(regs->bp, &sc->bp);
138 put_user_ex(regs->sp, &sc->sp);
139 put_user_ex(regs->bx, &sc->bx);
140 put_user_ex(regs->dx, &sc->dx);
141 put_user_ex(regs->cx, &sc->cx);
142 put_user_ex(regs->ax, &sc->ax);
143 #ifdef CONFIG_X86_64
144 put_user_ex(regs->r8, &sc->r8);
145 put_user_ex(regs->r9, &sc->r9);
146 put_user_ex(regs->r10, &sc->r10);
147 put_user_ex(regs->r11, &sc->r11);
148 put_user_ex(regs->r12, &sc->r12);
149 put_user_ex(regs->r13, &sc->r13);
150 put_user_ex(regs->r14, &sc->r14);
151 put_user_ex(regs->r15, &sc->r15);
152 #endif /* CONFIG_X86_64 */
153
154 put_user_ex(current->thread.trap_nr, &sc->trapno);
155 put_user_ex(current->thread.error_code, &sc->err);
156 put_user_ex(regs->ip, &sc->ip);
157 #ifdef CONFIG_X86_32
158 put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
159 put_user_ex(regs->flags, &sc->flags);
160 put_user_ex(regs->sp, &sc->sp_at_signal);
161 put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
162 #else /* !CONFIG_X86_32 */
163 put_user_ex(regs->flags, &sc->flags);
164 put_user_ex(regs->cs, &sc->cs);
165 put_user_ex(0, &sc->gs);
166 put_user_ex(0, &sc->fs);
167 #endif /* CONFIG_X86_32 */
168
169 put_user_ex(fpstate, &sc->fpstate);
170
171 /* non-iBCS2 extensions.. */
172 put_user_ex(mask, &sc->oldmask);
173 put_user_ex(current->thread.cr2, &sc->cr2);
174 } put_user_catch(err);
175
176 return err;
177 }
178
179 /*
180 * Set up a signal frame.
181 */
182
183 /*
184 * Determine which stack to use..
185 */
186 static unsigned long align_sigframe(unsigned long sp)
187 {
188 #ifdef CONFIG_X86_32
189 /*
190 * Align the stack pointer according to the i386 ABI,
191 * i.e. so that on function entry ((sp + 4) & 15) == 0.
192 */
193 sp = ((sp + 4) & -16ul) - 4;
194 #else /* !CONFIG_X86_32 */
195 sp = round_down(sp, 16) - 8;
196 #endif
197 return sp;
198 }
199
200 static inline void __user *
201 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
202 void __user **fpstate)
203 {
204 /* Default to using normal stack */
205 unsigned long math_size = 0;
206 unsigned long sp = regs->sp;
207 unsigned long buf_fx = 0;
208 int onsigstack = on_sig_stack(sp);
209
210 /* redzone */
211 if (config_enabled(CONFIG_X86_64))
212 sp -= 128;
213
214 if (!onsigstack) {
215 /* This is the X/Open sanctioned signal stack switching. */
216 if (ka->sa.sa_flags & SA_ONSTACK) {
217 if (current->sas_ss_size)
218 sp = current->sas_ss_sp + current->sas_ss_size;
219 } else if (config_enabled(CONFIG_X86_32) &&
220 (regs->ss & 0xffff) != __USER_DS &&
221 !(ka->sa.sa_flags & SA_RESTORER) &&
222 ka->sa.sa_restorer) {
223 /* This is the legacy signal stack switching. */
224 sp = (unsigned long) ka->sa.sa_restorer;
225 }
226 }
227
228 if (used_math()) {
229 sp = alloc_mathframe(sp, config_enabled(CONFIG_X86_32),
230 &buf_fx, &math_size);
231 *fpstate = (void __user *)sp;
232 }
233
234 sp = align_sigframe(sp - frame_size);
235
236 /*
237 * If we are on the alternate signal stack and would overflow it, don't.
238 * Return an always-bogus address instead so we will die with SIGSEGV.
239 */
240 if (onsigstack && !likely(on_sig_stack(sp)))
241 return (void __user *)-1L;
242
243 /* save i387 and extended state */
244 if (used_math() &&
245 save_xstate_sig(*fpstate, (void __user *)buf_fx, math_size) < 0)
246 return (void __user *)-1L;
247
248 return (void __user *)sp;
249 }
250
251 #ifdef CONFIG_X86_32
252 static const struct {
253 u16 poplmovl;
254 u32 val;
255 u16 int80;
256 } __attribute__((packed)) retcode = {
257 0xb858, /* popl %eax; movl $..., %eax */
258 __NR_sigreturn,
259 0x80cd, /* int $0x80 */
260 };
261
262 static const struct {
263 u8 movl;
264 u32 val;
265 u16 int80;
266 u8 pad;
267 } __attribute__((packed)) rt_retcode = {
268 0xb8, /* movl $..., %eax */
269 __NR_rt_sigreturn,
270 0x80cd, /* int $0x80 */
271 0
272 };
273
274 static int
275 __setup_frame(int sig, struct ksignal *ksig, sigset_t *set,
276 struct pt_regs *regs)
277 {
278 struct sigframe __user *frame;
279 void __user *restorer;
280 int err = 0;
281 void __user *fpstate = NULL;
282
283 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
284
285 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
286 return -EFAULT;
287
288 if (__put_user(sig, &frame->sig))
289 return -EFAULT;
290
291 if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
292 return -EFAULT;
293
294 if (_NSIG_WORDS > 1) {
295 if (__copy_to_user(&frame->extramask, &set->sig[1],
296 sizeof(frame->extramask)))
297 return -EFAULT;
298 }
299
300 if (current->mm->context.vdso)
301 restorer = current->mm->context.vdso +
302 selected_vdso32->sym___kernel_sigreturn;
303 else
304 restorer = &frame->retcode;
305 if (ksig->ka.sa.sa_flags & SA_RESTORER)
306 restorer = ksig->ka.sa.sa_restorer;
307
308 /* Set up to return from userspace. */
309 err |= __put_user(restorer, &frame->pretcode);
310
311 /*
312 * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
313 *
314 * WE DO NOT USE IT ANY MORE! It's only left here for historical
315 * reasons and because gdb uses it as a signature to notice
316 * signal handler stack frames.
317 */
318 err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode);
319
320 if (err)
321 return -EFAULT;
322
323 /* Set up registers for signal handler */
324 regs->sp = (unsigned long)frame;
325 regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
326 regs->ax = (unsigned long)sig;
327 regs->dx = 0;
328 regs->cx = 0;
329
330 regs->ds = __USER_DS;
331 regs->es = __USER_DS;
332 regs->ss = __USER_DS;
333 regs->cs = __USER_CS;
334
335 return 0;
336 }
337
338 static int __setup_rt_frame(int sig, struct ksignal *ksig,
339 sigset_t *set, struct pt_regs *regs)
340 {
341 struct rt_sigframe __user *frame;
342 void __user *restorer;
343 int err = 0;
344 void __user *fpstate = NULL;
345
346 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
347
348 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
349 return -EFAULT;
350
351 put_user_try {
352 put_user_ex(sig, &frame->sig);
353 put_user_ex(&frame->info, &frame->pinfo);
354 put_user_ex(&frame->uc, &frame->puc);
355
356 /* Create the ucontext. */
357 if (cpu_has_xsave)
358 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
359 else
360 put_user_ex(0, &frame->uc.uc_flags);
361 put_user_ex(0, &frame->uc.uc_link);
362 save_altstack_ex(&frame->uc.uc_stack, regs->sp);
363
364 /* Set up to return from userspace. */
365 restorer = current->mm->context.vdso +
366 selected_vdso32->sym___kernel_rt_sigreturn;
367 if (ksig->ka.sa.sa_flags & SA_RESTORER)
368 restorer = ksig->ka.sa.sa_restorer;
369 put_user_ex(restorer, &frame->pretcode);
370
371 /*
372 * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
373 *
374 * WE DO NOT USE IT ANY MORE! It's only left here for historical
375 * reasons and because gdb uses it as a signature to notice
376 * signal handler stack frames.
377 */
378 put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
379 } put_user_catch(err);
380
381 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
382 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
383 regs, set->sig[0]);
384 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
385
386 if (err)
387 return -EFAULT;
388
389 /* Set up registers for signal handler */
390 regs->sp = (unsigned long)frame;
391 regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
392 regs->ax = (unsigned long)sig;
393 regs->dx = (unsigned long)&frame->info;
394 regs->cx = (unsigned long)&frame->uc;
395
396 regs->ds = __USER_DS;
397 regs->es = __USER_DS;
398 regs->ss = __USER_DS;
399 regs->cs = __USER_CS;
400
401 return 0;
402 }
403 #else /* !CONFIG_X86_32 */
404 static int __setup_rt_frame(int sig, struct ksignal *ksig,
405 sigset_t *set, struct pt_regs *regs)
406 {
407 struct rt_sigframe __user *frame;
408 void __user *fp = NULL;
409 int err = 0;
410
411 frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp);
412
413 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
414 return -EFAULT;
415
416 if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
417 if (copy_siginfo_to_user(&frame->info, &ksig->info))
418 return -EFAULT;
419 }
420
421 put_user_try {
422 /* Create the ucontext. */
423 if (cpu_has_xsave)
424 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
425 else
426 put_user_ex(0, &frame->uc.uc_flags);
427 put_user_ex(0, &frame->uc.uc_link);
428 save_altstack_ex(&frame->uc.uc_stack, regs->sp);
429
430 /* Set up to return from userspace. If provided, use a stub
431 already in userspace. */
432 /* x86-64 should always use SA_RESTORER. */
433 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
434 put_user_ex(ksig->ka.sa.sa_restorer, &frame->pretcode);
435 } else {
436 /* could use a vstub here */
437 err |= -EFAULT;
438 }
439 } put_user_catch(err);
440
441 err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
442 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
443
444 if (err)
445 return -EFAULT;
446
447 /* Set up registers for signal handler */
448 regs->di = sig;
449 /* In case the signal handler was declared without prototypes */
450 regs->ax = 0;
451
452 /* This also works for non SA_SIGINFO handlers because they expect the
453 next argument after the signal number on the stack. */
454 regs->si = (unsigned long)&frame->info;
455 regs->dx = (unsigned long)&frame->uc;
456 regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
457
458 regs->sp = (unsigned long)frame;
459
460 /* Set up the CS register to run signal handlers in 64-bit mode,
461 even if the handler happens to be interrupting 32-bit code. */
462 regs->cs = __USER_CS;
463
464 return 0;
465 }
466 #endif /* CONFIG_X86_32 */
467
468 static int x32_setup_rt_frame(struct ksignal *ksig,
469 compat_sigset_t *set,
470 struct pt_regs *regs)
471 {
472 #ifdef CONFIG_X86_X32_ABI
473 struct rt_sigframe_x32 __user *frame;
474 void __user *restorer;
475 int err = 0;
476 void __user *fpstate = NULL;
477
478 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
479
480 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
481 return -EFAULT;
482
483 if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
484 if (copy_siginfo_to_user32(&frame->info, &ksig->info))
485 return -EFAULT;
486 }
487
488 put_user_try {
489 /* Create the ucontext. */
490 if (cpu_has_xsave)
491 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
492 else
493 put_user_ex(0, &frame->uc.uc_flags);
494 put_user_ex(0, &frame->uc.uc_link);
495 compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp);
496 put_user_ex(0, &frame->uc.uc__pad0);
497
498 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
499 restorer = ksig->ka.sa.sa_restorer;
500 } else {
501 /* could use a vstub here */
502 restorer = NULL;
503 err |= -EFAULT;
504 }
505 put_user_ex(restorer, &frame->pretcode);
506 } put_user_catch(err);
507
508 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
509 regs, set->sig[0]);
510 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
511
512 if (err)
513 return -EFAULT;
514
515 /* Set up registers for signal handler */
516 regs->sp = (unsigned long) frame;
517 regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
518
519 /* We use the x32 calling convention here... */
520 regs->di = ksig->sig;
521 regs->si = (unsigned long) &frame->info;
522 regs->dx = (unsigned long) &frame->uc;
523
524 loadsegment(ds, __USER_DS);
525 loadsegment(es, __USER_DS);
526
527 regs->cs = __USER_CS;
528 regs->ss = __USER_DS;
529 #endif /* CONFIG_X86_X32_ABI */
530
531 return 0;
532 }
533
534 /*
535 * Do a signal return; undo the signal stack.
536 */
537 #ifdef CONFIG_X86_32
538 asmlinkage unsigned long sys_sigreturn(void)
539 {
540 struct pt_regs *regs = current_pt_regs();
541 struct sigframe __user *frame;
542 unsigned long ax;
543 sigset_t set;
544
545 frame = (struct sigframe __user *)(regs->sp - 8);
546
547 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
548 goto badframe;
549 if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
550 && __copy_from_user(&set.sig[1], &frame->extramask,
551 sizeof(frame->extramask))))
552 goto badframe;
553
554 set_current_blocked(&set);
555
556 if (restore_sigcontext(regs, &frame->sc, &ax))
557 goto badframe;
558 return ax;
559
560 badframe:
561 signal_fault(regs, frame, "sigreturn");
562
563 return 0;
564 }
565 #endif /* CONFIG_X86_32 */
566
567 asmlinkage long sys_rt_sigreturn(void)
568 {
569 struct pt_regs *regs = current_pt_regs();
570 struct rt_sigframe __user *frame;
571 unsigned long ax;
572 sigset_t set;
573
574 frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
575 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
576 goto badframe;
577 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
578 goto badframe;
579
580 set_current_blocked(&set);
581
582 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
583 goto badframe;
584
585 if (restore_altstack(&frame->uc.uc_stack))
586 goto badframe;
587
588 return ax;
589
590 badframe:
591 signal_fault(regs, frame, "rt_sigreturn");
592 return 0;
593 }
594
595 /*
596 * OK, we're invoking a handler:
597 */
598 static int signr_convert(int sig)
599 {
600 #ifdef CONFIG_X86_32
601 struct thread_info *info = current_thread_info();
602
603 if (info->exec_domain && info->exec_domain->signal_invmap && sig < 32)
604 return info->exec_domain->signal_invmap[sig];
605 #endif /* CONFIG_X86_32 */
606 return sig;
607 }
608
609 static int
610 setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
611 {
612 int usig = signr_convert(ksig->sig);
613 sigset_t *set = sigmask_to_save();
614 compat_sigset_t *cset = (compat_sigset_t *) set;
615
616 /* Set up the stack frame */
617 if (is_ia32_frame()) {
618 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
619 return ia32_setup_rt_frame(usig, ksig, cset, regs);
620 else
621 return ia32_setup_frame(usig, ksig, cset, regs);
622 } else if (is_x32_frame()) {
623 return x32_setup_rt_frame(ksig, cset, regs);
624 } else {
625 return __setup_rt_frame(ksig->sig, ksig, set, regs);
626 }
627 }
628
629 static void
630 handle_signal(struct ksignal *ksig, struct pt_regs *regs)
631 {
632 bool failed;
633 /* Are we from a system call? */
634 if (syscall_get_nr(current, regs) >= 0) {
635 /* If so, check system call restarting.. */
636 switch (syscall_get_error(current, regs)) {
637 case -ERESTART_RESTARTBLOCK:
638 case -ERESTARTNOHAND:
639 regs->ax = -EINTR;
640 break;
641
642 case -ERESTARTSYS:
643 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
644 regs->ax = -EINTR;
645 break;
646 }
647 /* fallthrough */
648 case -ERESTARTNOINTR:
649 regs->ax = regs->orig_ax;
650 regs->ip -= 2;
651 break;
652 }
653 }
654
655 /*
656 * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
657 * flag so that register information in the sigcontext is correct.
658 */
659 if (unlikely(regs->flags & X86_EFLAGS_TF) &&
660 likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
661 regs->flags &= ~X86_EFLAGS_TF;
662
663 failed = (setup_rt_frame(ksig, regs) < 0);
664 if (!failed) {
665 /*
666 * Clear the direction flag as per the ABI for function entry.
667 *
668 * Clear RF when entering the signal handler, because
669 * it might disable possible debug exception from the
670 * signal handler.
671 *
672 * Clear TF when entering the signal handler, but
673 * notify any tracer that was single-stepping it.
674 * The tracer may want to single-step inside the
675 * handler too.
676 */
677 regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF);
678 /*
679 * Ensure the signal handler starts with the new fpu state.
680 */
681 if (used_math())
682 drop_init_fpu(current);
683 }
684 signal_setup_done(failed, ksig, test_thread_flag(TIF_SINGLESTEP));
685 }
686
687 #ifdef CONFIG_X86_32
688 #define NR_restart_syscall __NR_restart_syscall
689 #else /* !CONFIG_X86_32 */
690 #define NR_restart_syscall \
691 test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall
692 #endif /* CONFIG_X86_32 */
693
694 /*
695 * Note that 'init' is a special process: it doesn't get signals it doesn't
696 * want to handle. Thus you cannot kill init even with a SIGKILL even by
697 * mistake.
698 */
699 static void do_signal(struct pt_regs *regs)
700 {
701 struct ksignal ksig;
702
703 if (get_signal(&ksig)) {
704 /* Whee! Actually deliver the signal. */
705 handle_signal(&ksig, regs);
706 return;
707 }
708
709 /* Did we come from a system call? */
710 if (syscall_get_nr(current, regs) >= 0) {
711 /* Restart the system call - no handlers present */
712 switch (syscall_get_error(current, regs)) {
713 case -ERESTARTNOHAND:
714 case -ERESTARTSYS:
715 case -ERESTARTNOINTR:
716 regs->ax = regs->orig_ax;
717 regs->ip -= 2;
718 break;
719
720 case -ERESTART_RESTARTBLOCK:
721 regs->ax = NR_restart_syscall;
722 regs->ip -= 2;
723 break;
724 }
725 }
726
727 /*
728 * If there's no signal to deliver, we just put the saved sigmask
729 * back.
730 */
731 restore_saved_sigmask();
732 }
733
734 /*
735 * notification of userspace execution resumption
736 * - triggered by the TIF_WORK_MASK flags
737 */
738 __visible void
739 do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
740 {
741 user_exit();
742
743 if (thread_info_flags & _TIF_UPROBE)
744 uprobe_notify_resume(regs);
745
746 /* deal with pending signal delivery */
747 if (thread_info_flags & _TIF_SIGPENDING)
748 do_signal(regs);
749
750 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
751 clear_thread_flag(TIF_NOTIFY_RESUME);
752 tracehook_notify_resume(regs);
753 }
754 if (thread_info_flags & _TIF_USER_RETURN_NOTIFY)
755 fire_user_return_notifiers();
756
757 user_enter();
758 }
759
760 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
761 {
762 struct task_struct *me = current;
763
764 if (show_unhandled_signals && printk_ratelimit()) {
765 printk("%s"
766 "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
767 task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
768 me->comm, me->pid, where, frame,
769 regs->ip, regs->sp, regs->orig_ax);
770 print_vma_addr(" in ", regs->ip);
771 pr_cont("\n");
772 }
773
774 force_sig(SIGSEGV, me);
775 }
776
777 #ifdef CONFIG_X86_X32_ABI
778 asmlinkage long sys32_x32_rt_sigreturn(void)
779 {
780 struct pt_regs *regs = current_pt_regs();
781 struct rt_sigframe_x32 __user *frame;
782 sigset_t set;
783 unsigned long ax;
784
785 frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);
786
787 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
788 goto badframe;
789 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
790 goto badframe;
791
792 set_current_blocked(&set);
793
794 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
795 goto badframe;
796
797 if (compat_restore_altstack(&frame->uc.uc_stack))
798 goto badframe;
799
800 return ax;
801
802 badframe:
803 signal_fault(regs, frame, "x32 rt_sigreturn");
804 return 0;
805 }
806 #endif
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