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
restore_sigcontext(struct pt_regs * regs,struct sigcontext __user * sc)64 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
65 {
66 void __user *buf;
67 unsigned int tmpflags;
68 unsigned int err = 0;
69
70 /* Always make any pending restarted system calls return -EINTR */
71 current->restart_block.fn = do_no_restart_syscall;
72
73 get_user_try {
74
75 #ifdef CONFIG_X86_32
76 set_user_gs(regs, GET_SEG(gs));
77 COPY_SEG(fs);
78 COPY_SEG(es);
79 COPY_SEG(ds);
80 #endif /* CONFIG_X86_32 */
81
82 COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
83 COPY(dx); COPY(cx); COPY(ip); COPY(ax);
84
85 #ifdef CONFIG_X86_64
86 COPY(r8);
87 COPY(r9);
88 COPY(r10);
89 COPY(r11);
90 COPY(r12);
91 COPY(r13);
92 COPY(r14);
93 COPY(r15);
94 #endif /* CONFIG_X86_64 */
95
96 #ifdef CONFIG_X86_32
97 COPY_SEG_CPL3(cs);
98 COPY_SEG_CPL3(ss);
99 #else /* !CONFIG_X86_32 */
100 /* Kernel saves and restores only the CS segment register on signals,
101 * which is the bare minimum needed to allow mixed 32/64-bit code.
102 * App's signal handler can save/restore other segments if needed. */
103 COPY_SEG_CPL3(cs);
104 #endif /* CONFIG_X86_32 */
105
106 get_user_ex(tmpflags, &sc->flags);
107 regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
108 regs->orig_ax = -1; /* disable syscall checks */
109
110 get_user_ex(buf, &sc->fpstate);
111 } get_user_catch(err);
112
113 err |= restore_xstate_sig(buf, config_enabled(CONFIG_X86_32));
114
115 force_iret();
116
117 return err;
118 }
119
setup_sigcontext(struct sigcontext __user * sc,void __user * fpstate,struct pt_regs * regs,unsigned long mask)120 int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
121 struct pt_regs *regs, unsigned long mask)
122 {
123 int err = 0;
124
125 put_user_try {
126
127 #ifdef CONFIG_X86_32
128 put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs);
129 put_user_ex(regs->fs, (unsigned int __user *)&sc->fs);
130 put_user_ex(regs->es, (unsigned int __user *)&sc->es);
131 put_user_ex(regs->ds, (unsigned int __user *)&sc->ds);
132 #endif /* CONFIG_X86_32 */
133
134 put_user_ex(regs->di, &sc->di);
135 put_user_ex(regs->si, &sc->si);
136 put_user_ex(regs->bp, &sc->bp);
137 put_user_ex(regs->sp, &sc->sp);
138 put_user_ex(regs->bx, &sc->bx);
139 put_user_ex(regs->dx, &sc->dx);
140 put_user_ex(regs->cx, &sc->cx);
141 put_user_ex(regs->ax, &sc->ax);
142 #ifdef CONFIG_X86_64
143 put_user_ex(regs->r8, &sc->r8);
144 put_user_ex(regs->r9, &sc->r9);
145 put_user_ex(regs->r10, &sc->r10);
146 put_user_ex(regs->r11, &sc->r11);
147 put_user_ex(regs->r12, &sc->r12);
148 put_user_ex(regs->r13, &sc->r13);
149 put_user_ex(regs->r14, &sc->r14);
150 put_user_ex(regs->r15, &sc->r15);
151 #endif /* CONFIG_X86_64 */
152
153 put_user_ex(current->thread.trap_nr, &sc->trapno);
154 put_user_ex(current->thread.error_code, &sc->err);
155 put_user_ex(regs->ip, &sc->ip);
156 #ifdef CONFIG_X86_32
157 put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
158 put_user_ex(regs->flags, &sc->flags);
159 put_user_ex(regs->sp, &sc->sp_at_signal);
160 put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
161 #else /* !CONFIG_X86_32 */
162 put_user_ex(regs->flags, &sc->flags);
163 put_user_ex(regs->cs, &sc->cs);
164 put_user_ex(0, &sc->gs);
165 put_user_ex(0, &sc->fs);
166 #endif /* CONFIG_X86_32 */
167
168 put_user_ex(fpstate, &sc->fpstate);
169
170 /* non-iBCS2 extensions.. */
171 put_user_ex(mask, &sc->oldmask);
172 put_user_ex(current->thread.cr2, &sc->cr2);
173 } put_user_catch(err);
174
175 return err;
176 }
177
178 /*
179 * Set up a signal frame.
180 */
181
182 /*
183 * Determine which stack to use..
184 */
align_sigframe(unsigned long sp)185 static unsigned long align_sigframe(unsigned long sp)
186 {
187 #ifdef CONFIG_X86_32
188 /*
189 * Align the stack pointer according to the i386 ABI,
190 * i.e. so that on function entry ((sp + 4) & 15) == 0.
191 */
192 sp = ((sp + 4) & -16ul) - 4;
193 #else /* !CONFIG_X86_32 */
194 sp = round_down(sp, 16) - 8;
195 #endif
196 return sp;
197 }
198
199 static inline void __user *
get_sigframe(struct k_sigaction * ka,struct pt_regs * regs,size_t frame_size,void __user ** fpstate)200 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
201 void __user **fpstate)
202 {
203 /* Default to using normal stack */
204 unsigned long math_size = 0;
205 unsigned long sp = regs->sp;
206 unsigned long buf_fx = 0;
207 int onsigstack = on_sig_stack(sp);
208
209 /* redzone */
210 if (config_enabled(CONFIG_X86_64))
211 sp -= 128;
212
213 if (!onsigstack) {
214 /* This is the X/Open sanctioned signal stack switching. */
215 if (ka->sa.sa_flags & SA_ONSTACK) {
216 if (current->sas_ss_size)
217 sp = current->sas_ss_sp + current->sas_ss_size;
218 } else if (config_enabled(CONFIG_X86_32) &&
219 (regs->ss & 0xffff) != __USER_DS &&
220 !(ka->sa.sa_flags & SA_RESTORER) &&
221 ka->sa.sa_restorer) {
222 /* This is the legacy signal stack switching. */
223 sp = (unsigned long) ka->sa.sa_restorer;
224 }
225 }
226
227 if (used_math()) {
228 sp = alloc_mathframe(sp, config_enabled(CONFIG_X86_32),
229 &buf_fx, &math_size);
230 *fpstate = (void __user *)sp;
231 }
232
233 sp = align_sigframe(sp - frame_size);
234
235 /*
236 * If we are on the alternate signal stack and would overflow it, don't.
237 * Return an always-bogus address instead so we will die with SIGSEGV.
238 */
239 if (onsigstack && !likely(on_sig_stack(sp)))
240 return (void __user *)-1L;
241
242 /* save i387 and extended state */
243 if (used_math() &&
244 save_xstate_sig(*fpstate, (void __user *)buf_fx, math_size) < 0)
245 return (void __user *)-1L;
246
247 return (void __user *)sp;
248 }
249
250 #ifdef CONFIG_X86_32
251 static const struct {
252 u16 poplmovl;
253 u32 val;
254 u16 int80;
255 } __attribute__((packed)) retcode = {
256 0xb858, /* popl %eax; movl $..., %eax */
257 __NR_sigreturn,
258 0x80cd, /* int $0x80 */
259 };
260
261 static const struct {
262 u8 movl;
263 u32 val;
264 u16 int80;
265 u8 pad;
266 } __attribute__((packed)) rt_retcode = {
267 0xb8, /* movl $..., %eax */
268 __NR_rt_sigreturn,
269 0x80cd, /* int $0x80 */
270 0
271 };
272
273 static int
__setup_frame(int sig,struct ksignal * ksig,sigset_t * set,struct pt_regs * regs)274 __setup_frame(int sig, struct ksignal *ksig, sigset_t *set,
275 struct pt_regs *regs)
276 {
277 struct sigframe __user *frame;
278 void __user *restorer;
279 int err = 0;
280 void __user *fpstate = NULL;
281
282 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
283
284 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
285 return -EFAULT;
286
287 if (__put_user(sig, &frame->sig))
288 return -EFAULT;
289
290 if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
291 return -EFAULT;
292
293 if (_NSIG_WORDS > 1) {
294 if (__copy_to_user(&frame->extramask, &set->sig[1],
295 sizeof(frame->extramask)))
296 return -EFAULT;
297 }
298
299 if (current->mm->context.vdso)
300 restorer = current->mm->context.vdso +
301 selected_vdso32->sym___kernel_sigreturn;
302 else
303 restorer = &frame->retcode;
304 if (ksig->ka.sa.sa_flags & SA_RESTORER)
305 restorer = ksig->ka.sa.sa_restorer;
306
307 /* Set up to return from userspace. */
308 err |= __put_user(restorer, &frame->pretcode);
309
310 /*
311 * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
312 *
313 * WE DO NOT USE IT ANY MORE! It's only left here for historical
314 * reasons and because gdb uses it as a signature to notice
315 * signal handler stack frames.
316 */
317 err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode);
318
319 if (err)
320 return -EFAULT;
321
322 /* Set up registers for signal handler */
323 regs->sp = (unsigned long)frame;
324 regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
325 regs->ax = (unsigned long)sig;
326 regs->dx = 0;
327 regs->cx = 0;
328
329 regs->ds = __USER_DS;
330 regs->es = __USER_DS;
331 regs->ss = __USER_DS;
332 regs->cs = __USER_CS;
333
334 return 0;
335 }
336
__setup_rt_frame(int sig,struct ksignal * ksig,sigset_t * set,struct pt_regs * regs)337 static int __setup_rt_frame(int sig, struct ksignal *ksig,
338 sigset_t *set, struct pt_regs *regs)
339 {
340 struct rt_sigframe __user *frame;
341 void __user *restorer;
342 int err = 0;
343 void __user *fpstate = NULL;
344
345 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
346
347 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
348 return -EFAULT;
349
350 put_user_try {
351 put_user_ex(sig, &frame->sig);
352 put_user_ex(&frame->info, &frame->pinfo);
353 put_user_ex(&frame->uc, &frame->puc);
354
355 /* Create the ucontext. */
356 if (cpu_has_xsave)
357 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
358 else
359 put_user_ex(0, &frame->uc.uc_flags);
360 put_user_ex(0, &frame->uc.uc_link);
361 save_altstack_ex(&frame->uc.uc_stack, regs->sp);
362
363 /* Set up to return from userspace. */
364 restorer = current->mm->context.vdso +
365 selected_vdso32->sym___kernel_rt_sigreturn;
366 if (ksig->ka.sa.sa_flags & SA_RESTORER)
367 restorer = ksig->ka.sa.sa_restorer;
368 put_user_ex(restorer, &frame->pretcode);
369
370 /*
371 * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
372 *
373 * WE DO NOT USE IT ANY MORE! It's only left here for historical
374 * reasons and because gdb uses it as a signature to notice
375 * signal handler stack frames.
376 */
377 put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
378 } put_user_catch(err);
379
380 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
381 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
382 regs, set->sig[0]);
383 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
384
385 if (err)
386 return -EFAULT;
387
388 /* Set up registers for signal handler */
389 regs->sp = (unsigned long)frame;
390 regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
391 regs->ax = (unsigned long)sig;
392 regs->dx = (unsigned long)&frame->info;
393 regs->cx = (unsigned long)&frame->uc;
394
395 regs->ds = __USER_DS;
396 regs->es = __USER_DS;
397 regs->ss = __USER_DS;
398 regs->cs = __USER_CS;
399
400 return 0;
401 }
402 #else /* !CONFIG_X86_32 */
__setup_rt_frame(int sig,struct ksignal * ksig,sigset_t * set,struct pt_regs * regs)403 static int __setup_rt_frame(int sig, struct ksignal *ksig,
404 sigset_t *set, struct pt_regs *regs)
405 {
406 struct rt_sigframe __user *frame;
407 void __user *fp = NULL;
408 int err = 0;
409
410 frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp);
411
412 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
413 return -EFAULT;
414
415 if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
416 if (copy_siginfo_to_user(&frame->info, &ksig->info))
417 return -EFAULT;
418 }
419
420 put_user_try {
421 /* Create the ucontext. */
422 if (cpu_has_xsave)
423 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
424 else
425 put_user_ex(0, &frame->uc.uc_flags);
426 put_user_ex(0, &frame->uc.uc_link);
427 save_altstack_ex(&frame->uc.uc_stack, regs->sp);
428
429 /* Set up to return from userspace. If provided, use a stub
430 already in userspace. */
431 /* x86-64 should always use SA_RESTORER. */
432 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
433 put_user_ex(ksig->ka.sa.sa_restorer, &frame->pretcode);
434 } else {
435 /* could use a vstub here */
436 err |= -EFAULT;
437 }
438 } put_user_catch(err);
439
440 err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
441 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
442
443 if (err)
444 return -EFAULT;
445
446 /* Set up registers for signal handler */
447 regs->di = sig;
448 /* In case the signal handler was declared without prototypes */
449 regs->ax = 0;
450
451 /* This also works for non SA_SIGINFO handlers because they expect the
452 next argument after the signal number on the stack. */
453 regs->si = (unsigned long)&frame->info;
454 regs->dx = (unsigned long)&frame->uc;
455 regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
456
457 regs->sp = (unsigned long)frame;
458
459 /* Set up the CS register to run signal handlers in 64-bit mode,
460 even if the handler happens to be interrupting 32-bit code. */
461 regs->cs = __USER_CS;
462
463 return 0;
464 }
465 #endif /* CONFIG_X86_32 */
466
x32_setup_rt_frame(struct ksignal * ksig,compat_sigset_t * set,struct pt_regs * regs)467 static int x32_setup_rt_frame(struct ksignal *ksig,
468 compat_sigset_t *set,
469 struct pt_regs *regs)
470 {
471 #ifdef CONFIG_X86_X32_ABI
472 struct rt_sigframe_x32 __user *frame;
473 void __user *restorer;
474 int err = 0;
475 void __user *fpstate = NULL;
476
477 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
478
479 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
480 return -EFAULT;
481
482 if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
483 if (copy_siginfo_to_user32(&frame->info, &ksig->info))
484 return -EFAULT;
485 }
486
487 put_user_try {
488 /* Create the ucontext. */
489 if (cpu_has_xsave)
490 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
491 else
492 put_user_ex(0, &frame->uc.uc_flags);
493 put_user_ex(0, &frame->uc.uc_link);
494 compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp);
495 put_user_ex(0, &frame->uc.uc__pad0);
496
497 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
498 restorer = ksig->ka.sa.sa_restorer;
499 } else {
500 /* could use a vstub here */
501 restorer = NULL;
502 err |= -EFAULT;
503 }
504 put_user_ex(restorer, &frame->pretcode);
505 } put_user_catch(err);
506
507 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
508 regs, set->sig[0]);
509 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
510
511 if (err)
512 return -EFAULT;
513
514 /* Set up registers for signal handler */
515 regs->sp = (unsigned long) frame;
516 regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
517
518 /* We use the x32 calling convention here... */
519 regs->di = ksig->sig;
520 regs->si = (unsigned long) &frame->info;
521 regs->dx = (unsigned long) &frame->uc;
522
523 loadsegment(ds, __USER_DS);
524 loadsegment(es, __USER_DS);
525
526 regs->cs = __USER_CS;
527 regs->ss = __USER_DS;
528 #endif /* CONFIG_X86_X32_ABI */
529
530 return 0;
531 }
532
533 /*
534 * Do a signal return; undo the signal stack.
535 */
536 #ifdef CONFIG_X86_32
sys_sigreturn(void)537 asmlinkage unsigned long sys_sigreturn(void)
538 {
539 struct pt_regs *regs = current_pt_regs();
540 struct sigframe __user *frame;
541 sigset_t set;
542
543 frame = (struct sigframe __user *)(regs->sp - 8);
544
545 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
546 goto badframe;
547 if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
548 && __copy_from_user(&set.sig[1], &frame->extramask,
549 sizeof(frame->extramask))))
550 goto badframe;
551
552 set_current_blocked(&set);
553
554 if (restore_sigcontext(regs, &frame->sc))
555 goto badframe;
556 return regs->ax;
557
558 badframe:
559 signal_fault(regs, frame, "sigreturn");
560
561 return 0;
562 }
563 #endif /* CONFIG_X86_32 */
564
sys_rt_sigreturn(void)565 asmlinkage long sys_rt_sigreturn(void)
566 {
567 struct pt_regs *regs = current_pt_regs();
568 struct rt_sigframe __user *frame;
569 sigset_t set;
570
571 frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
572 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
573 goto badframe;
574 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
575 goto badframe;
576
577 set_current_blocked(&set);
578
579 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
580 goto badframe;
581
582 if (restore_altstack(&frame->uc.uc_stack))
583 goto badframe;
584
585 return regs->ax;
586
587 badframe:
588 signal_fault(regs, frame, "rt_sigreturn");
589 return 0;
590 }
591
592 static int
setup_rt_frame(struct ksignal * ksig,struct pt_regs * regs)593 setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
594 {
595 int usig = ksig->sig;
596 sigset_t *set = sigmask_to_save();
597 compat_sigset_t *cset = (compat_sigset_t *) set;
598
599 /* Set up the stack frame */
600 if (is_ia32_frame()) {
601 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
602 return ia32_setup_rt_frame(usig, ksig, cset, regs);
603 else
604 return ia32_setup_frame(usig, ksig, cset, regs);
605 } else if (is_x32_frame()) {
606 return x32_setup_rt_frame(ksig, cset, regs);
607 } else {
608 return __setup_rt_frame(ksig->sig, ksig, set, regs);
609 }
610 }
611
612 static void
handle_signal(struct ksignal * ksig,struct pt_regs * regs)613 handle_signal(struct ksignal *ksig, struct pt_regs *regs)
614 {
615 bool stepping, failed;
616
617 /* Are we from a system call? */
618 if (syscall_get_nr(current, regs) >= 0) {
619 /* If so, check system call restarting.. */
620 switch (syscall_get_error(current, regs)) {
621 case -ERESTART_RESTARTBLOCK:
622 case -ERESTARTNOHAND:
623 regs->ax = -EINTR;
624 break;
625
626 case -ERESTARTSYS:
627 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
628 regs->ax = -EINTR;
629 break;
630 }
631 /* fallthrough */
632 case -ERESTARTNOINTR:
633 regs->ax = regs->orig_ax;
634 regs->ip -= 2;
635 break;
636 }
637 }
638
639 /*
640 * If TF is set due to a debugger (TIF_FORCED_TF), clear TF now
641 * so that register information in the sigcontext is correct and
642 * then notify the tracer before entering the signal handler.
643 */
644 stepping = test_thread_flag(TIF_SINGLESTEP);
645 if (stepping)
646 user_disable_single_step(current);
647
648 failed = (setup_rt_frame(ksig, regs) < 0);
649 if (!failed) {
650 /*
651 * Clear the direction flag as per the ABI for function entry.
652 *
653 * Clear RF when entering the signal handler, because
654 * it might disable possible debug exception from the
655 * signal handler.
656 *
657 * Clear TF for the case when it wasn't set by debugger to
658 * avoid the recursive send_sigtrap() in SIGTRAP handler.
659 */
660 regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF);
661 /*
662 * Ensure the signal handler starts with the new fpu state.
663 */
664 if (used_math())
665 fpu_reset_state(current);
666 }
667 signal_setup_done(failed, ksig, stepping);
668 }
669
get_nr_restart_syscall(const struct pt_regs * regs)670 static inline unsigned long get_nr_restart_syscall(const struct pt_regs *regs)
671 {
672 #if defined(CONFIG_X86_32) || !defined(CONFIG_X86_64)
673 return __NR_restart_syscall;
674 #else /* !CONFIG_X86_32 && CONFIG_X86_64 */
675 return test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall :
676 __NR_restart_syscall | (regs->orig_ax & __X32_SYSCALL_BIT);
677 #endif /* CONFIG_X86_32 || !CONFIG_X86_64 */
678 }
679
680 /*
681 * Note that 'init' is a special process: it doesn't get signals it doesn't
682 * want to handle. Thus you cannot kill init even with a SIGKILL even by
683 * mistake.
684 */
do_signal(struct pt_regs * regs)685 static void do_signal(struct pt_regs *regs)
686 {
687 struct ksignal ksig;
688
689 if (get_signal(&ksig)) {
690 /* Whee! Actually deliver the signal. */
691 handle_signal(&ksig, regs);
692 return;
693 }
694
695 /* Did we come from a system call? */
696 if (syscall_get_nr(current, regs) >= 0) {
697 /* Restart the system call - no handlers present */
698 switch (syscall_get_error(current, regs)) {
699 case -ERESTARTNOHAND:
700 case -ERESTARTSYS:
701 case -ERESTARTNOINTR:
702 regs->ax = regs->orig_ax;
703 regs->ip -= 2;
704 break;
705
706 case -ERESTART_RESTARTBLOCK:
707 regs->ax = get_nr_restart_syscall(regs);
708 regs->ip -= 2;
709 break;
710 }
711 }
712
713 /*
714 * If there's no signal to deliver, we just put the saved sigmask
715 * back.
716 */
717 restore_saved_sigmask();
718 }
719
720 /*
721 * notification of userspace execution resumption
722 * - triggered by the TIF_WORK_MASK flags
723 */
724 __visible void
do_notify_resume(struct pt_regs * regs,void * unused,__u32 thread_info_flags)725 do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
726 {
727 user_exit();
728
729 if (thread_info_flags & _TIF_UPROBE)
730 uprobe_notify_resume(regs);
731
732 /* deal with pending signal delivery */
733 if (thread_info_flags & _TIF_SIGPENDING)
734 do_signal(regs);
735
736 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
737 clear_thread_flag(TIF_NOTIFY_RESUME);
738 tracehook_notify_resume(regs);
739 }
740 if (thread_info_flags & _TIF_USER_RETURN_NOTIFY)
741 fire_user_return_notifiers();
742
743 user_enter();
744 }
745
signal_fault(struct pt_regs * regs,void __user * frame,char * where)746 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
747 {
748 struct task_struct *me = current;
749
750 if (show_unhandled_signals && printk_ratelimit()) {
751 printk("%s"
752 "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
753 task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
754 me->comm, me->pid, where, frame,
755 regs->ip, regs->sp, regs->orig_ax);
756 print_vma_addr(" in ", regs->ip);
757 pr_cont("\n");
758 }
759
760 force_sig(SIGSEGV, me);
761 }
762
763 #ifdef CONFIG_X86_X32_ABI
sys32_x32_rt_sigreturn(void)764 asmlinkage long sys32_x32_rt_sigreturn(void)
765 {
766 struct pt_regs *regs = current_pt_regs();
767 struct rt_sigframe_x32 __user *frame;
768 sigset_t set;
769
770 frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);
771
772 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
773 goto badframe;
774 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
775 goto badframe;
776
777 set_current_blocked(&set);
778
779 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
780 goto badframe;
781
782 if (compat_restore_altstack(&frame->uc.uc_stack))
783 goto badframe;
784
785 return regs->ax;
786
787 badframe:
788 signal_fault(regs, frame, "x32 rt_sigreturn");
789 return 0;
790 }
791 #endif
792