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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#include <linux/sched.h>
10#include <linux/mm.h>
11#include <linux/smp.h>
12#include <linux/kernel.h>
13#include <linux/errno.h>
14#include <linux/wait.h>
15#include <linux/tracehook.h>
16#include <linux/unistd.h>
17#include <linux/stddef.h>
18#include <linux/personality.h>
19#include <linux/uaccess.h>
20#include <linux/user-return-notifier.h>
21#include <linux/uprobes.h>
22
23#include <asm/processor.h>
24#include <asm/ucontext.h>
25#include <asm/i387.h>
26#include <asm/fpu-internal.h>
27#include <asm/vdso.h>
28#include <asm/mce.h>
29#include <asm/sighandling.h>
30
31#ifdef CONFIG_X86_64
32#include <asm/proto.h>
33#include <asm/ia32_unistd.h>
34#include <asm/sys_ia32.h>
35#endif /* CONFIG_X86_64 */
36
37#include <asm/syscall.h>
38#include <asm/syscalls.h>
39
40#include <asm/sigframe.h>
41
42#ifdef CONFIG_X86_32
43# define FIX_EFLAGS (__FIX_EFLAGS | X86_EFLAGS_RF)
44#else
45# define FIX_EFLAGS __FIX_EFLAGS
46#endif
47
48#define COPY(x) do { \
49 get_user_ex(regs->x, &sc->x); \
50} while (0)
51
52#define GET_SEG(seg) ({ \
53 unsigned short tmp; \
54 get_user_ex(tmp, &sc->seg); \
55 tmp; \
56})
57
58#define COPY_SEG(seg) do { \
59 regs->seg = GET_SEG(seg); \
60} while (0)
61
62#define COPY_SEG_CPL3(seg) do { \
63 regs->seg = GET_SEG(seg) | 3; \
64} while (0)
65
66int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
67 unsigned long *pax)
68{
69 void __user *buf;
70 unsigned int tmpflags;
71 unsigned int err = 0;
72
73 /* Always make any pending restarted system calls return -EINTR */
74 current_thread_info()->restart_block.fn = do_no_restart_syscall;
75
76 get_user_try {
77
78#ifdef CONFIG_X86_32
79 set_user_gs(regs, GET_SEG(gs));
80 COPY_SEG(fs);
81 COPY_SEG(es);
82 COPY_SEG(ds);
83#endif /* CONFIG_X86_32 */
84
85 COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
86 COPY(dx); COPY(cx); COPY(ip);
87
88#ifdef CONFIG_X86_64
89 COPY(r8);
90 COPY(r9);
91 COPY(r10);
92 COPY(r11);
93 COPY(r12);
94 COPY(r13);
95 COPY(r14);
96 COPY(r15);
97#endif /* CONFIG_X86_64 */
98
99#ifdef CONFIG_X86_32
100 COPY_SEG_CPL3(cs);
101 COPY_SEG_CPL3(ss);
102#else /* !CONFIG_X86_32 */
103 /* Kernel saves and restores only the CS segment register on signals,
104 * which is the bare minimum needed to allow mixed 32/64-bit code.
105 * App's signal handler can save/restore other segments if needed. */
106 COPY_SEG_CPL3(cs);
107#endif /* CONFIG_X86_32 */
108
109 get_user_ex(tmpflags, &sc->flags);
110 regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
111 regs->orig_ax = -1; /* disable syscall checks */
112
113 get_user_ex(buf, &sc->fpstate);
114 err |= restore_i387_xstate(buf);
115
116 get_user_ex(*pax, &sc->ax);
117 } get_user_catch(err);
118
119 return err;
120}
121
122int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
123 struct pt_regs *regs, unsigned long mask)
124{
125 int err = 0;
126
127 put_user_try {
128
129#ifdef CONFIG_X86_32
130 put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs);
131 put_user_ex(regs->fs, (unsigned int __user *)&sc->fs);
132 put_user_ex(regs->es, (unsigned int __user *)&sc->es);
133 put_user_ex(regs->ds, (unsigned int __user *)&sc->ds);
134#endif /* CONFIG_X86_32 */
135
136 put_user_ex(regs->di, &sc->di);
137 put_user_ex(regs->si, &sc->si);
138 put_user_ex(regs->bp, &sc->bp);
139 put_user_ex(regs->sp, &sc->sp);
140 put_user_ex(regs->bx, &sc->bx);
141 put_user_ex(regs->dx, &sc->dx);
142 put_user_ex(regs->cx, &sc->cx);
143 put_user_ex(regs->ax, &sc->ax);
144#ifdef CONFIG_X86_64
145 put_user_ex(regs->r8, &sc->r8);
146 put_user_ex(regs->r9, &sc->r9);
147 put_user_ex(regs->r10, &sc->r10);
148 put_user_ex(regs->r11, &sc->r11);
149 put_user_ex(regs->r12, &sc->r12);
150 put_user_ex(regs->r13, &sc->r13);
151 put_user_ex(regs->r14, &sc->r14);
152 put_user_ex(regs->r15, &sc->r15);
153#endif /* CONFIG_X86_64 */
154
155 put_user_ex(current->thread.trap_nr, &sc->trapno);
156 put_user_ex(current->thread.error_code, &sc->err);
157 put_user_ex(regs->ip, &sc->ip);
158#ifdef CONFIG_X86_32
159 put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
160 put_user_ex(regs->flags, &sc->flags);
161 put_user_ex(regs->sp, &sc->sp_at_signal);
162 put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
163#else /* !CONFIG_X86_32 */
164 put_user_ex(regs->flags, &sc->flags);
165 put_user_ex(regs->cs, &sc->cs);
166 put_user_ex(0, &sc->gs);
167 put_user_ex(0, &sc->fs);
168#endif /* CONFIG_X86_32 */
169
170 put_user_ex(fpstate, &sc->fpstate);
171
172 /* non-iBCS2 extensions.. */
173 put_user_ex(mask, &sc->oldmask);
174 put_user_ex(current->thread.cr2, &sc->cr2);
175 } put_user_catch(err);
176
177 return err;
178}
179
180/*
181 * Set up a signal frame.
182 */
183
184/*
185 * Determine which stack to use..
186 */
187static unsigned long align_sigframe(unsigned long sp)
188{
189#ifdef CONFIG_X86_32
190 /*
191 * Align the stack pointer according to the i386 ABI,
192 * i.e. so that on function entry ((sp + 4) & 15) == 0.
193 */
194 sp = ((sp + 4) & -16ul) - 4;
195#else /* !CONFIG_X86_32 */
196 sp = round_down(sp, 16) - 8;
197#endif
198 return sp;
199}
200
201static inline void __user *
202get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
203 void __user **fpstate)
204{
205 /* Default to using normal stack */
206 unsigned long sp = regs->sp;
207 int onsigstack = on_sig_stack(sp);
208
209#ifdef CONFIG_X86_64
210 /* redzone */
211 sp -= 128;
212#endif /* CONFIG_X86_64 */
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 {
220#ifdef CONFIG_X86_32
221 /* This is the legacy signal stack switching. */
222 if ((regs->ss & 0xffff) != __USER_DS &&
223 !(ka->sa.sa_flags & SA_RESTORER) &&
224 ka->sa.sa_restorer)
225 sp = (unsigned long) ka->sa.sa_restorer;
226#endif /* CONFIG_X86_32 */
227 }
228 }
229
230 if (used_math()) {
231 sp -= sig_xstate_size;
232#ifdef CONFIG_X86_64
233 sp = round_down(sp, 64);
234#endif /* CONFIG_X86_64 */
235 *fpstate = (void __user *)sp;
236 }
237
238 sp = align_sigframe(sp - frame_size);
239
240 /*
241 * If we are on the alternate signal stack and would overflow it, don't.
242 * Return an always-bogus address instead so we will die with SIGSEGV.
243 */
244 if (onsigstack && !likely(on_sig_stack(sp)))
245 return (void __user *)-1L;
246
247 /* save i387 state */
248 if (used_math() && save_i387_xstate(*fpstate) < 0)
249 return (void __user *)-1L;
250
251 return (void __user *)sp;
252}
253
254#ifdef CONFIG_X86_32
255static const struct {
256 u16 poplmovl;
257 u32 val;
258 u16 int80;
259} __attribute__((packed)) retcode = {
260 0xb858, /* popl %eax; movl $..., %eax */
261 __NR_sigreturn,
262 0x80cd, /* int $0x80 */
263};
264
265static const struct {
266 u8 movl;
267 u32 val;
268 u16 int80;
269 u8 pad;
270} __attribute__((packed)) rt_retcode = {
271 0xb8, /* movl $..., %eax */
272 __NR_rt_sigreturn,
273 0x80cd, /* int $0x80 */
274 0
275};
276
277static int
278__setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
279 struct pt_regs *regs)
280{
281 struct sigframe __user *frame;
282 void __user *restorer;
283 int err = 0;
284 void __user *fpstate = NULL;
285
286 frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
287
288 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
289 return -EFAULT;
290
291 if (__put_user(sig, &frame->sig))
292 return -EFAULT;
293
294 if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
295 return -EFAULT;
296
297 if (_NSIG_WORDS > 1) {
298 if (__copy_to_user(&frame->extramask, &set->sig[1],
299 sizeof(frame->extramask)))
300 return -EFAULT;
301 }
302
303 if (current->mm->context.vdso)
304 restorer = VDSO32_SYMBOL(current->mm->context.vdso, sigreturn);
305 else
306 restorer = &frame->retcode;
307 if (ka->sa.sa_flags & SA_RESTORER)
308 restorer = ka->sa.sa_restorer;
309
310 /* Set up to return from userspace. */
311 err |= __put_user(restorer, &frame->pretcode);
312
313 /*
314 * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
315 *
316 * WE DO NOT USE IT ANY MORE! It's only left here for historical
317 * reasons and because gdb uses it as a signature to notice
318 * signal handler stack frames.
319 */
320 err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode);
321
322 if (err)
323 return -EFAULT;
324
325 /* Set up registers for signal handler */
326 regs->sp = (unsigned long)frame;
327 regs->ip = (unsigned long)ka->sa.sa_handler;
328 regs->ax = (unsigned long)sig;
329 regs->dx = 0;
330 regs->cx = 0;
331
332 regs->ds = __USER_DS;
333 regs->es = __USER_DS;
334 regs->ss = __USER_DS;
335 regs->cs = __USER_CS;
336
337 return 0;
338}
339
340static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
341 sigset_t *set, struct pt_regs *regs)
342{
343 struct rt_sigframe __user *frame;
344 void __user *restorer;
345 int err = 0;
346 void __user *fpstate = NULL;
347
348 frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
349
350 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
351 return -EFAULT;
352
353 put_user_try {
354 put_user_ex(sig, &frame->sig);
355 put_user_ex(&frame->info, &frame->pinfo);
356 put_user_ex(&frame->uc, &frame->puc);
357 err |= copy_siginfo_to_user(&frame->info, info);
358
359 /* Create the ucontext. */
360 if (cpu_has_xsave)
361 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
362 else
363 put_user_ex(0, &frame->uc.uc_flags);
364 put_user_ex(0, &frame->uc.uc_link);
365 put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
366 put_user_ex(sas_ss_flags(regs->sp),
367 &frame->uc.uc_stack.ss_flags);
368 put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
369 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
370 regs, set->sig[0]);
371 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
372
373 /* Set up to return from userspace. */
374 restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn);
375 if (ka->sa.sa_flags & SA_RESTORER)
376 restorer = ka->sa.sa_restorer;
377 put_user_ex(restorer, &frame->pretcode);
378
379 /*
380 * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
381 *
382 * WE DO NOT USE IT ANY MORE! It's only left here for historical
383 * reasons and because gdb uses it as a signature to notice
384 * signal handler stack frames.
385 */
386 put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
387 } put_user_catch(err);
388
389 if (err)
390 return -EFAULT;
391
392 /* Set up registers for signal handler */
393 regs->sp = (unsigned long)frame;
394 regs->ip = (unsigned long)ka->sa.sa_handler;
395 regs->ax = (unsigned long)sig;
396 regs->dx = (unsigned long)&frame->info;
397 regs->cx = (unsigned long)&frame->uc;
398
399 regs->ds = __USER_DS;
400 regs->es = __USER_DS;
401 regs->ss = __USER_DS;
402 regs->cs = __USER_CS;
403
404 return 0;
405}
406#else /* !CONFIG_X86_32 */
407static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
408 sigset_t *set, struct pt_regs *regs)
409{
410 struct rt_sigframe __user *frame;
411 void __user *fp = NULL;
412 int err = 0;
413 struct task_struct *me = current;
414
415 frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe), &fp);
416
417 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
418 return -EFAULT;
419
420 if (ka->sa.sa_flags & SA_SIGINFO) {
421 if (copy_siginfo_to_user(&frame->info, info))
422 return -EFAULT;
423 }
424
425 put_user_try {
426 /* Create the ucontext. */
427 if (cpu_has_xsave)
428 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
429 else
430 put_user_ex(0, &frame->uc.uc_flags);
431 put_user_ex(0, &frame->uc.uc_link);
432 put_user_ex(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
433 put_user_ex(sas_ss_flags(regs->sp),
434 &frame->uc.uc_stack.ss_flags);
435 put_user_ex(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
436 err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
437 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
438
439 /* Set up to return from userspace. If provided, use a stub
440 already in userspace. */
441 /* x86-64 should always use SA_RESTORER. */
442 if (ka->sa.sa_flags & SA_RESTORER) {
443 put_user_ex(ka->sa.sa_restorer, &frame->pretcode);
444 } else {
445 /* could use a vstub here */
446 err |= -EFAULT;
447 }
448 } put_user_catch(err);
449
450 if (err)
451 return -EFAULT;
452
453 /* Set up registers for signal handler */
454 regs->di = sig;
455 /* In case the signal handler was declared without prototypes */
456 regs->ax = 0;
457
458 /* This also works for non SA_SIGINFO handlers because they expect the
459 next argument after the signal number on the stack. */
460 regs->si = (unsigned long)&frame->info;
461 regs->dx = (unsigned long)&frame->uc;
462 regs->ip = (unsigned long) ka->sa.sa_handler;
463
464 regs->sp = (unsigned long)frame;
465
466 /* Set up the CS register to run signal handlers in 64-bit mode,
467 even if the handler happens to be interrupting 32-bit code. */
468 regs->cs = __USER_CS;
469
470 return 0;
471}
472#endif /* CONFIG_X86_32 */
473
474#ifdef CONFIG_X86_32
475/*
476 * Atomically swap in the new signal mask, and wait for a signal.
477 */
478asmlinkage int
479sys_sigsuspend(int history0, int history1, old_sigset_t mask)
480{
481 sigset_t blocked;
482 siginitset(&blocked, mask);
483 return sigsuspend(&blocked);
484}
485
486asmlinkage int
487sys_sigaction(int sig, const struct old_sigaction __user *act,
488 struct old_sigaction __user *oact)
489{
490 struct k_sigaction new_ka, old_ka;
491 int ret = 0;
492
493 if (act) {
494 old_sigset_t mask;
495
496 if (!access_ok(VERIFY_READ, act, sizeof(*act)))
497 return -EFAULT;
498
499 get_user_try {
500 get_user_ex(new_ka.sa.sa_handler, &act->sa_handler);
501 get_user_ex(new_ka.sa.sa_flags, &act->sa_flags);
502 get_user_ex(mask, &act->sa_mask);
503 get_user_ex(new_ka.sa.sa_restorer, &act->sa_restorer);
504 } get_user_catch(ret);
505
506 if (ret)
507 return -EFAULT;
508 siginitset(&new_ka.sa.sa_mask, mask);
509 }
510
511 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
512
513 if (!ret && oact) {
514 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
515 return -EFAULT;
516
517 put_user_try {
518 put_user_ex(old_ka.sa.sa_handler, &oact->sa_handler);
519 put_user_ex(old_ka.sa.sa_flags, &oact->sa_flags);
520 put_user_ex(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
521 put_user_ex(old_ka.sa.sa_restorer, &oact->sa_restorer);
522 } put_user_catch(ret);
523
524 if (ret)
525 return -EFAULT;
526 }
527
528 return ret;
529}
530#endif /* CONFIG_X86_32 */
531
532long
533sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
534 struct pt_regs *regs)
535{
536 return do_sigaltstack(uss, uoss, regs->sp);
537}
538
539/*
540 * Do a signal return; undo the signal stack.
541 */
542#ifdef CONFIG_X86_32
543unsigned long sys_sigreturn(struct pt_regs *regs)
544{
545 struct sigframe __user *frame;
546 unsigned long ax;
547 sigset_t set;
548
549 frame = (struct sigframe __user *)(regs->sp - 8);
550
551 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
552 goto badframe;
553 if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
554 && __copy_from_user(&set.sig[1], &frame->extramask,
555 sizeof(frame->extramask))))
556 goto badframe;
557
558 set_current_blocked(&set);
559
560 if (restore_sigcontext(regs, &frame->sc, &ax))
561 goto badframe;
562 return ax;
563
564badframe:
565 signal_fault(regs, frame, "sigreturn");
566
567 return 0;
568}
569#endif /* CONFIG_X86_32 */
570
571long sys_rt_sigreturn(struct pt_regs *regs)
572{
573 struct rt_sigframe __user *frame;
574 unsigned long ax;
575 sigset_t set;
576
577 frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
578 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
579 goto badframe;
580 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
581 goto badframe;
582
583 set_current_blocked(&set);
584
585 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
586 goto badframe;
587
588 if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
589 goto badframe;
590
591 return ax;
592
593badframe:
594 signal_fault(regs, frame, "rt_sigreturn");
595 return 0;
596}
597
598/*
599 * OK, we're invoking a handler:
600 */
601static int signr_convert(int sig)
602{
603#ifdef CONFIG_X86_32
604 struct thread_info *info = current_thread_info();
605
606 if (info->exec_domain && info->exec_domain->signal_invmap && sig < 32)
607 return info->exec_domain->signal_invmap[sig];
608#endif /* CONFIG_X86_32 */
609 return sig;
610}
611
612#ifdef CONFIG_X86_32
613
614#define is_ia32 1
615#define ia32_setup_frame __setup_frame
616#define ia32_setup_rt_frame __setup_rt_frame
617
618#else /* !CONFIG_X86_32 */
619
620#ifdef CONFIG_IA32_EMULATION
621#define is_ia32 test_thread_flag(TIF_IA32)
622#else /* !CONFIG_IA32_EMULATION */
623#define is_ia32 0
624#endif /* CONFIG_IA32_EMULATION */
625
626#ifdef CONFIG_X86_X32_ABI
627#define is_x32 test_thread_flag(TIF_X32)
628
629static int x32_setup_rt_frame(int sig, struct k_sigaction *ka,
630 siginfo_t *info, compat_sigset_t *set,
631 struct pt_regs *regs);
632#else /* !CONFIG_X86_X32_ABI */
633#define is_x32 0
634#endif /* CONFIG_X86_X32_ABI */
635
636int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
637 sigset_t *set, struct pt_regs *regs);
638int ia32_setup_frame(int sig, struct k_sigaction *ka,
639 sigset_t *set, struct pt_regs *regs);
640
641#endif /* CONFIG_X86_32 */
642
643static int
644setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
645 struct pt_regs *regs)
646{
647 int usig = signr_convert(sig);
648 sigset_t *set = sigmask_to_save();
649
650 /* Set up the stack frame */
651 if (is_ia32) {
652 if (ka->sa.sa_flags & SA_SIGINFO)
653 return ia32_setup_rt_frame(usig, ka, info, set, regs);
654 else
655 return ia32_setup_frame(usig, ka, set, regs);
656#ifdef CONFIG_X86_X32_ABI
657 } else if (is_x32) {
658 return x32_setup_rt_frame(usig, ka, info,
659 (compat_sigset_t *)set, regs);
660#endif
661 } else {
662 return __setup_rt_frame(sig, ka, info, set, regs);
663 }
664}
665
666static void
667handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
668 struct pt_regs *regs)
669{
670 /* Are we from a system call? */
671 if (syscall_get_nr(current, regs) >= 0) {
672 /* If so, check system call restarting.. */
673 switch (syscall_get_error(current, regs)) {
674 case -ERESTART_RESTARTBLOCK:
675 case -ERESTARTNOHAND:
676 regs->ax = -EINTR;
677 break;
678
679 case -ERESTARTSYS:
680 if (!(ka->sa.sa_flags & SA_RESTART)) {
681 regs->ax = -EINTR;
682 break;
683 }
684 /* fallthrough */
685 case -ERESTARTNOINTR:
686 regs->ax = regs->orig_ax;
687 regs->ip -= 2;
688 break;
689 }
690 }
691
692 /*
693 * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
694 * flag so that register information in the sigcontext is correct.
695 */
696 if (unlikely(regs->flags & X86_EFLAGS_TF) &&
697 likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
698 regs->flags &= ~X86_EFLAGS_TF;
699
700 if (setup_rt_frame(sig, ka, info, regs) < 0) {
701 force_sigsegv(sig, current);
702 return;
703 }
704
705 /*
706 * Clear the direction flag as per the ABI for function entry.
707 */
708 regs->flags &= ~X86_EFLAGS_DF;
709
710 /*
711 * Clear TF when entering the signal handler, but
712 * notify any tracer that was single-stepping it.
713 * The tracer may want to single-step inside the
714 * handler too.
715 */
716 regs->flags &= ~X86_EFLAGS_TF;
717
718 signal_delivered(sig, info, ka, regs,
719 test_thread_flag(TIF_SINGLESTEP));
720}
721
722#ifdef CONFIG_X86_32
723#define NR_restart_syscall __NR_restart_syscall
724#else /* !CONFIG_X86_32 */
725#define NR_restart_syscall \
726 test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall
727#endif /* CONFIG_X86_32 */
728
729/*
730 * Note that 'init' is a special process: it doesn't get signals it doesn't
731 * want to handle. Thus you cannot kill init even with a SIGKILL even by
732 * mistake.
733 */
734static void do_signal(struct pt_regs *regs)
735{
736 struct k_sigaction ka;
737 siginfo_t info;
738 int signr;
739
740 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
741 if (signr > 0) {
742 /* Whee! Actually deliver the signal. */
743 handle_signal(signr, &info, &ka, regs);
744 return;
745 }
746
747 /* Did we come from a system call? */
748 if (syscall_get_nr(current, regs) >= 0) {
749 /* Restart the system call - no handlers present */
750 switch (syscall_get_error(current, regs)) {
751 case -ERESTARTNOHAND:
752 case -ERESTARTSYS:
753 case -ERESTARTNOINTR:
754 regs->ax = regs->orig_ax;
755 regs->ip -= 2;
756 break;
757
758 case -ERESTART_RESTARTBLOCK:
759 regs->ax = NR_restart_syscall;
760 regs->ip -= 2;
761 break;
762 }
763 }
764
765 /*
766 * If there's no signal to deliver, we just put the saved sigmask
767 * back.
768 */
769 restore_saved_sigmask();
770}
771
772/*
773 * notification of userspace execution resumption
774 * - triggered by the TIF_WORK_MASK flags
775 */
776void
777do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
778{
779#ifdef CONFIG_X86_MCE
780 /* notify userspace of pending MCEs */
781 if (thread_info_flags & _TIF_MCE_NOTIFY)
782 mce_notify_process();
783#endif /* CONFIG_X86_64 && CONFIG_X86_MCE */
784
785 if (thread_info_flags & _TIF_UPROBE) {
786 clear_thread_flag(TIF_UPROBE);
787 uprobe_notify_resume(regs);
788 }
789
790 /* deal with pending signal delivery */
791 if (thread_info_flags & _TIF_SIGPENDING)
792 do_signal(regs);
793
794 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
795 clear_thread_flag(TIF_NOTIFY_RESUME);
796 tracehook_notify_resume(regs);
797 }
798 if (thread_info_flags & _TIF_USER_RETURN_NOTIFY)
799 fire_user_return_notifiers();
800
801#ifdef CONFIG_X86_32
802 clear_thread_flag(TIF_IRET);
803#endif /* CONFIG_X86_32 */
804}
805
806void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
807{
808 struct task_struct *me = current;
809
810 if (show_unhandled_signals && printk_ratelimit()) {
811 printk("%s"
812 "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
813 task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
814 me->comm, me->pid, where, frame,
815 regs->ip, regs->sp, regs->orig_ax);
816 print_vma_addr(" in ", regs->ip);
817 printk(KERN_CONT "\n");
818 }
819
820 force_sig(SIGSEGV, me);
821}
822
823#ifdef CONFIG_X86_X32_ABI
824static int x32_setup_rt_frame(int sig, struct k_sigaction *ka,
825 siginfo_t *info, compat_sigset_t *set,
826 struct pt_regs *regs)
827{
828 struct rt_sigframe_x32 __user *frame;
829 void __user *restorer;
830 int err = 0;
831 void __user *fpstate = NULL;
832
833 frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
834
835 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
836 return -EFAULT;
837
838 if (ka->sa.sa_flags & SA_SIGINFO) {
839 if (copy_siginfo_to_user32(&frame->info, info))
840 return -EFAULT;
841 }
842
843 put_user_try {
844 /* Create the ucontext. */
845 if (cpu_has_xsave)
846 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
847 else
848 put_user_ex(0, &frame->uc.uc_flags);
849 put_user_ex(0, &frame->uc.uc_link);
850 put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
851 put_user_ex(sas_ss_flags(regs->sp),
852 &frame->uc.uc_stack.ss_flags);
853 put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
854 put_user_ex(0, &frame->uc.uc__pad0);
855 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
856 regs, set->sig[0]);
857 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
858
859 if (ka->sa.sa_flags & SA_RESTORER) {
860 restorer = ka->sa.sa_restorer;
861 } else {
862 /* could use a vstub here */
863 restorer = NULL;
864 err |= -EFAULT;
865 }
866 put_user_ex(restorer, &frame->pretcode);
867 } put_user_catch(err);
868
869 if (err)
870 return -EFAULT;
871
872 /* Set up registers for signal handler */
873 regs->sp = (unsigned long) frame;
874 regs->ip = (unsigned long) ka->sa.sa_handler;
875
876 /* We use the x32 calling convention here... */
877 regs->di = sig;
878 regs->si = (unsigned long) &frame->info;
879 regs->dx = (unsigned long) &frame->uc;
880
881 loadsegment(ds, __USER_DS);
882 loadsegment(es, __USER_DS);
883
884 regs->cs = __USER_CS;
885 regs->ss = __USER_DS;
886
887 return 0;
888}
889
890asmlinkage long sys32_x32_rt_sigreturn(struct pt_regs *regs)
891{
892 struct rt_sigframe_x32 __user *frame;
893 sigset_t set;
894 unsigned long ax;
895 struct pt_regs tregs;
896
897 frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);
898
899 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
900 goto badframe;
901 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
902 goto badframe;
903
904 set_current_blocked(&set);
905
906 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
907 goto badframe;
908
909 tregs = *regs;
910 if (sys32_sigaltstack(&frame->uc.uc_stack, NULL, &tregs) == -EFAULT)
911 goto badframe;
912
913 return ax;
914
915badframe:
916 signal_fault(regs, frame, "x32 rt_sigreturn");
917 return 0;
918}
919#endif
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#include <linux/sched.h>
10#include <linux/mm.h>
11#include <linux/smp.h>
12#include <linux/kernel.h>
13#include <linux/signal.h>
14#include <linux/errno.h>
15#include <linux/wait.h>
16#include <linux/ptrace.h>
17#include <linux/tracehook.h>
18#include <linux/unistd.h>
19#include <linux/stddef.h>
20#include <linux/personality.h>
21#include <linux/uaccess.h>
22#include <linux/user-return-notifier.h>
23
24#include <asm/processor.h>
25#include <asm/ucontext.h>
26#include <asm/i387.h>
27#include <asm/vdso.h>
28#include <asm/mce.h>
29
30#ifdef CONFIG_X86_64
31#include <asm/proto.h>
32#include <asm/ia32_unistd.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
191/*
192 * Determine which stack to use..
193 */
194static unsigned long align_sigframe(unsigned long sp)
195{
196#ifdef CONFIG_X86_32
197 /*
198 * Align the stack pointer according to the i386 ABI,
199 * i.e. so that on function entry ((sp + 4) & 15) == 0.
200 */
201 sp = ((sp + 4) & -16ul) - 4;
202#else /* !CONFIG_X86_32 */
203 sp = round_down(sp, 16) - 8;
204#endif
205 return sp;
206}
207
208static inline void __user *
209get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
210 void __user **fpstate)
211{
212 /* Default to using normal stack */
213 unsigned long sp = regs->sp;
214 int onsigstack = on_sig_stack(sp);
215
216#ifdef CONFIG_X86_64
217 /* redzone */
218 sp -= 128;
219#endif /* CONFIG_X86_64 */
220
221 if (!onsigstack) {
222 /* This is the X/Open sanctioned signal stack switching. */
223 if (ka->sa.sa_flags & SA_ONSTACK) {
224 if (current->sas_ss_size)
225 sp = current->sas_ss_sp + current->sas_ss_size;
226 } else {
227#ifdef CONFIG_X86_32
228 /* This is the legacy signal stack switching. */
229 if ((regs->ss & 0xffff) != __USER_DS &&
230 !(ka->sa.sa_flags & SA_RESTORER) &&
231 ka->sa.sa_restorer)
232 sp = (unsigned long) ka->sa.sa_restorer;
233#endif /* CONFIG_X86_32 */
234 }
235 }
236
237 if (used_math()) {
238 sp -= sig_xstate_size;
239#ifdef CONFIG_X86_64
240 sp = round_down(sp, 64);
241#endif /* CONFIG_X86_64 */
242 *fpstate = (void __user *)sp;
243 }
244
245 sp = align_sigframe(sp - frame_size);
246
247 /*
248 * If we are on the alternate signal stack and would overflow it, don't.
249 * Return an always-bogus address instead so we will die with SIGSEGV.
250 */
251 if (onsigstack && !likely(on_sig_stack(sp)))
252 return (void __user *)-1L;
253
254 /* save i387 state */
255 if (used_math() && save_i387_xstate(*fpstate) < 0)
256 return (void __user *)-1L;
257
258 return (void __user *)sp;
259}
260
261#ifdef CONFIG_X86_32
262static const struct {
263 u16 poplmovl;
264 u32 val;
265 u16 int80;
266} __attribute__((packed)) retcode = {
267 0xb858, /* popl %eax; movl $..., %eax */
268 __NR_sigreturn,
269 0x80cd, /* int $0x80 */
270};
271
272static const struct {
273 u8 movl;
274 u32 val;
275 u16 int80;
276 u8 pad;
277} __attribute__((packed)) rt_retcode = {
278 0xb8, /* movl $..., %eax */
279 __NR_rt_sigreturn,
280 0x80cd, /* int $0x80 */
281 0
282};
283
284static int
285__setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
286 struct pt_regs *regs)
287{
288 struct sigframe __user *frame;
289 void __user *restorer;
290 int err = 0;
291 void __user *fpstate = NULL;
292
293 frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
294
295 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
296 return -EFAULT;
297
298 if (__put_user(sig, &frame->sig))
299 return -EFAULT;
300
301 if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
302 return -EFAULT;
303
304 if (_NSIG_WORDS > 1) {
305 if (__copy_to_user(&frame->extramask, &set->sig[1],
306 sizeof(frame->extramask)))
307 return -EFAULT;
308 }
309
310 if (current->mm->context.vdso)
311 restorer = VDSO32_SYMBOL(current->mm->context.vdso, sigreturn);
312 else
313 restorer = &frame->retcode;
314 if (ka->sa.sa_flags & SA_RESTORER)
315 restorer = ka->sa.sa_restorer;
316
317 /* Set up to return from userspace. */
318 err |= __put_user(restorer, &frame->pretcode);
319
320 /*
321 * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
322 *
323 * WE DO NOT USE IT ANY MORE! It's only left here for historical
324 * reasons and because gdb uses it as a signature to notice
325 * signal handler stack frames.
326 */
327 err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode);
328
329 if (err)
330 return -EFAULT;
331
332 /* Set up registers for signal handler */
333 regs->sp = (unsigned long)frame;
334 regs->ip = (unsigned long)ka->sa.sa_handler;
335 regs->ax = (unsigned long)sig;
336 regs->dx = 0;
337 regs->cx = 0;
338
339 regs->ds = __USER_DS;
340 regs->es = __USER_DS;
341 regs->ss = __USER_DS;
342 regs->cs = __USER_CS;
343
344 return 0;
345}
346
347static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
348 sigset_t *set, struct pt_regs *regs)
349{
350 struct rt_sigframe __user *frame;
351 void __user *restorer;
352 int err = 0;
353 void __user *fpstate = NULL;
354
355 frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
356
357 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
358 return -EFAULT;
359
360 put_user_try {
361 put_user_ex(sig, &frame->sig);
362 put_user_ex(&frame->info, &frame->pinfo);
363 put_user_ex(&frame->uc, &frame->puc);
364 err |= copy_siginfo_to_user(&frame->info, info);
365
366 /* Create the ucontext. */
367 if (cpu_has_xsave)
368 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
369 else
370 put_user_ex(0, &frame->uc.uc_flags);
371 put_user_ex(0, &frame->uc.uc_link);
372 put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
373 put_user_ex(sas_ss_flags(regs->sp),
374 &frame->uc.uc_stack.ss_flags);
375 put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
376 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
377 regs, set->sig[0]);
378 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
379
380 /* Set up to return from userspace. */
381 restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn);
382 if (ka->sa.sa_flags & SA_RESTORER)
383 restorer = ka->sa.sa_restorer;
384 put_user_ex(restorer, &frame->pretcode);
385
386 /*
387 * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
388 *
389 * WE DO NOT USE IT ANY MORE! It's only left here for historical
390 * reasons and because gdb uses it as a signature to notice
391 * signal handler stack frames.
392 */
393 put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
394 } put_user_catch(err);
395
396 if (err)
397 return -EFAULT;
398
399 /* Set up registers for signal handler */
400 regs->sp = (unsigned long)frame;
401 regs->ip = (unsigned long)ka->sa.sa_handler;
402 regs->ax = (unsigned long)sig;
403 regs->dx = (unsigned long)&frame->info;
404 regs->cx = (unsigned long)&frame->uc;
405
406 regs->ds = __USER_DS;
407 regs->es = __USER_DS;
408 regs->ss = __USER_DS;
409 regs->cs = __USER_CS;
410
411 return 0;
412}
413#else /* !CONFIG_X86_32 */
414static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
415 sigset_t *set, struct pt_regs *regs)
416{
417 struct rt_sigframe __user *frame;
418 void __user *fp = NULL;
419 int err = 0;
420 struct task_struct *me = current;
421
422 frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe), &fp);
423
424 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
425 return -EFAULT;
426
427 if (ka->sa.sa_flags & SA_SIGINFO) {
428 if (copy_siginfo_to_user(&frame->info, info))
429 return -EFAULT;
430 }
431
432 put_user_try {
433 /* Create the ucontext. */
434 if (cpu_has_xsave)
435 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
436 else
437 put_user_ex(0, &frame->uc.uc_flags);
438 put_user_ex(0, &frame->uc.uc_link);
439 put_user_ex(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
440 put_user_ex(sas_ss_flags(regs->sp),
441 &frame->uc.uc_stack.ss_flags);
442 put_user_ex(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
443 err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
444 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
445
446 /* Set up to return from userspace. If provided, use a stub
447 already in userspace. */
448 /* x86-64 should always use SA_RESTORER. */
449 if (ka->sa.sa_flags & SA_RESTORER) {
450 put_user_ex(ka->sa.sa_restorer, &frame->pretcode);
451 } else {
452 /* could use a vstub here */
453 err |= -EFAULT;
454 }
455 } put_user_catch(err);
456
457 if (err)
458 return -EFAULT;
459
460 /* Set up registers for signal handler */
461 regs->di = sig;
462 /* In case the signal handler was declared without prototypes */
463 regs->ax = 0;
464
465 /* This also works for non SA_SIGINFO handlers because they expect the
466 next argument after the signal number on the stack. */
467 regs->si = (unsigned long)&frame->info;
468 regs->dx = (unsigned long)&frame->uc;
469 regs->ip = (unsigned long) ka->sa.sa_handler;
470
471 regs->sp = (unsigned long)frame;
472
473 /* Set up the CS register to run signal handlers in 64-bit mode,
474 even if the handler happens to be interrupting 32-bit code. */
475 regs->cs = __USER_CS;
476
477 return 0;
478}
479#endif /* CONFIG_X86_32 */
480
481#ifdef CONFIG_X86_32
482/*
483 * Atomically swap in the new signal mask, and wait for a signal.
484 */
485asmlinkage int
486sys_sigsuspend(int history0, int history1, old_sigset_t mask)
487{
488 sigset_t blocked;
489
490 current->saved_sigmask = current->blocked;
491
492 mask &= _BLOCKABLE;
493 siginitset(&blocked, mask);
494 set_current_blocked(&blocked);
495
496 current->state = TASK_INTERRUPTIBLE;
497 schedule();
498
499 set_restore_sigmask();
500 return -ERESTARTNOHAND;
501}
502
503asmlinkage int
504sys_sigaction(int sig, const struct old_sigaction __user *act,
505 struct old_sigaction __user *oact)
506{
507 struct k_sigaction new_ka, old_ka;
508 int ret = 0;
509
510 if (act) {
511 old_sigset_t mask;
512
513 if (!access_ok(VERIFY_READ, act, sizeof(*act)))
514 return -EFAULT;
515
516 get_user_try {
517 get_user_ex(new_ka.sa.sa_handler, &act->sa_handler);
518 get_user_ex(new_ka.sa.sa_flags, &act->sa_flags);
519 get_user_ex(mask, &act->sa_mask);
520 get_user_ex(new_ka.sa.sa_restorer, &act->sa_restorer);
521 } get_user_catch(ret);
522
523 if (ret)
524 return -EFAULT;
525 siginitset(&new_ka.sa.sa_mask, mask);
526 }
527
528 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
529
530 if (!ret && oact) {
531 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
532 return -EFAULT;
533
534 put_user_try {
535 put_user_ex(old_ka.sa.sa_handler, &oact->sa_handler);
536 put_user_ex(old_ka.sa.sa_flags, &oact->sa_flags);
537 put_user_ex(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
538 put_user_ex(old_ka.sa.sa_restorer, &oact->sa_restorer);
539 } put_user_catch(ret);
540
541 if (ret)
542 return -EFAULT;
543 }
544
545 return ret;
546}
547#endif /* CONFIG_X86_32 */
548
549long
550sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
551 struct pt_regs *regs)
552{
553 return do_sigaltstack(uss, uoss, regs->sp);
554}
555
556/*
557 * Do a signal return; undo the signal stack.
558 */
559#ifdef CONFIG_X86_32
560unsigned long sys_sigreturn(struct pt_regs *regs)
561{
562 struct sigframe __user *frame;
563 unsigned long ax;
564 sigset_t set;
565
566 frame = (struct sigframe __user *)(regs->sp - 8);
567
568 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
569 goto badframe;
570 if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
571 && __copy_from_user(&set.sig[1], &frame->extramask,
572 sizeof(frame->extramask))))
573 goto badframe;
574
575 sigdelsetmask(&set, ~_BLOCKABLE);
576 set_current_blocked(&set);
577
578 if (restore_sigcontext(regs, &frame->sc, &ax))
579 goto badframe;
580 return ax;
581
582badframe:
583 signal_fault(regs, frame, "sigreturn");
584
585 return 0;
586}
587#endif /* CONFIG_X86_32 */
588
589long sys_rt_sigreturn(struct pt_regs *regs)
590{
591 struct rt_sigframe __user *frame;
592 unsigned long ax;
593 sigset_t set;
594
595 frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
596 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
597 goto badframe;
598 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
599 goto badframe;
600
601 sigdelsetmask(&set, ~_BLOCKABLE);
602 set_current_blocked(&set);
603
604 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
605 goto badframe;
606
607 if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
608 goto badframe;
609
610 return ax;
611
612badframe:
613 signal_fault(regs, frame, "rt_sigreturn");
614 return 0;
615}
616
617/*
618 * OK, we're invoking a handler:
619 */
620static int signr_convert(int sig)
621{
622#ifdef CONFIG_X86_32
623 struct thread_info *info = current_thread_info();
624
625 if (info->exec_domain && info->exec_domain->signal_invmap && sig < 32)
626 return info->exec_domain->signal_invmap[sig];
627#endif /* CONFIG_X86_32 */
628 return sig;
629}
630
631#ifdef CONFIG_X86_32
632
633#define is_ia32 1
634#define ia32_setup_frame __setup_frame
635#define ia32_setup_rt_frame __setup_rt_frame
636
637#else /* !CONFIG_X86_32 */
638
639#ifdef CONFIG_IA32_EMULATION
640#define is_ia32 test_thread_flag(TIF_IA32)
641#else /* !CONFIG_IA32_EMULATION */
642#define is_ia32 0
643#endif /* CONFIG_IA32_EMULATION */
644
645int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
646 sigset_t *set, struct pt_regs *regs);
647int ia32_setup_frame(int sig, struct k_sigaction *ka,
648 sigset_t *set, struct pt_regs *regs);
649
650#endif /* CONFIG_X86_32 */
651
652static int
653setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
654 struct pt_regs *regs)
655{
656 int usig = signr_convert(sig);
657 sigset_t *set = ¤t->blocked;
658 int ret;
659
660 if (current_thread_info()->status & TS_RESTORE_SIGMASK)
661 set = ¤t->saved_sigmask;
662
663 /* Set up the stack frame */
664 if (is_ia32) {
665 if (ka->sa.sa_flags & SA_SIGINFO)
666 ret = ia32_setup_rt_frame(usig, ka, info, set, regs);
667 else
668 ret = ia32_setup_frame(usig, ka, set, regs);
669 } else
670 ret = __setup_rt_frame(sig, ka, info, set, regs);
671
672 if (ret) {
673 force_sigsegv(sig, current);
674 return -EFAULT;
675 }
676
677 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
678 return ret;
679}
680
681static int
682handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
683 struct pt_regs *regs)
684{
685 sigset_t blocked;
686 int ret;
687
688 /* Are we from a system call? */
689 if (syscall_get_nr(current, regs) >= 0) {
690 /* If so, check system call restarting.. */
691 switch (syscall_get_error(current, regs)) {
692 case -ERESTART_RESTARTBLOCK:
693 case -ERESTARTNOHAND:
694 regs->ax = -EINTR;
695 break;
696
697 case -ERESTARTSYS:
698 if (!(ka->sa.sa_flags & SA_RESTART)) {
699 regs->ax = -EINTR;
700 break;
701 }
702 /* fallthrough */
703 case -ERESTARTNOINTR:
704 regs->ax = regs->orig_ax;
705 regs->ip -= 2;
706 break;
707 }
708 }
709
710 /*
711 * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
712 * flag so that register information in the sigcontext is correct.
713 */
714 if (unlikely(regs->flags & X86_EFLAGS_TF) &&
715 likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
716 regs->flags &= ~X86_EFLAGS_TF;
717
718 ret = setup_rt_frame(sig, ka, info, regs);
719
720 if (ret)
721 return ret;
722
723 /*
724 * Clear the direction flag as per the ABI for function entry.
725 */
726 regs->flags &= ~X86_EFLAGS_DF;
727
728 /*
729 * Clear TF when entering the signal handler, but
730 * notify any tracer that was single-stepping it.
731 * The tracer may want to single-step inside the
732 * handler too.
733 */
734 regs->flags &= ~X86_EFLAGS_TF;
735
736 sigorsets(&blocked, ¤t->blocked, &ka->sa.sa_mask);
737 if (!(ka->sa.sa_flags & SA_NODEFER))
738 sigaddset(&blocked, sig);
739 set_current_blocked(&blocked);
740
741 tracehook_signal_handler(sig, info, ka, regs,
742 test_thread_flag(TIF_SINGLESTEP));
743
744 return 0;
745}
746
747#ifdef CONFIG_X86_32
748#define NR_restart_syscall __NR_restart_syscall
749#else /* !CONFIG_X86_32 */
750#define NR_restart_syscall \
751 test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall
752#endif /* CONFIG_X86_32 */
753
754/*
755 * Note that 'init' is a special process: it doesn't get signals it doesn't
756 * want to handle. Thus you cannot kill init even with a SIGKILL even by
757 * mistake.
758 */
759static void do_signal(struct pt_regs *regs)
760{
761 struct k_sigaction ka;
762 siginfo_t info;
763 int signr;
764
765 /*
766 * We want the common case to go fast, which is why we may in certain
767 * cases get here from kernel mode. Just return without doing anything
768 * if so.
769 * X86_32: vm86 regs switched out by assembly code before reaching
770 * here, so testing against kernel CS suffices.
771 */
772 if (!user_mode(regs))
773 return;
774
775 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
776 if (signr > 0) {
777 /* Whee! Actually deliver the signal. */
778 handle_signal(signr, &info, &ka, regs);
779 return;
780 }
781
782 /* Did we come from a system call? */
783 if (syscall_get_nr(current, regs) >= 0) {
784 /* Restart the system call - no handlers present */
785 switch (syscall_get_error(current, regs)) {
786 case -ERESTARTNOHAND:
787 case -ERESTARTSYS:
788 case -ERESTARTNOINTR:
789 regs->ax = regs->orig_ax;
790 regs->ip -= 2;
791 break;
792
793 case -ERESTART_RESTARTBLOCK:
794 regs->ax = NR_restart_syscall;
795 regs->ip -= 2;
796 break;
797 }
798 }
799
800 /*
801 * If there's no signal to deliver, we just put the saved sigmask
802 * back.
803 */
804 if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
805 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
806 set_current_blocked(¤t->saved_sigmask);
807 }
808}
809
810/*
811 * notification of userspace execution resumption
812 * - triggered by the TIF_WORK_MASK flags
813 */
814void
815do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
816{
817#ifdef CONFIG_X86_MCE
818 /* notify userspace of pending MCEs */
819 if (thread_info_flags & _TIF_MCE_NOTIFY)
820 mce_notify_process();
821#endif /* CONFIG_X86_64 && CONFIG_X86_MCE */
822
823 /* deal with pending signal delivery */
824 if (thread_info_flags & _TIF_SIGPENDING)
825 do_signal(regs);
826
827 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
828 clear_thread_flag(TIF_NOTIFY_RESUME);
829 tracehook_notify_resume(regs);
830 if (current->replacement_session_keyring)
831 key_replace_session_keyring();
832 }
833 if (thread_info_flags & _TIF_USER_RETURN_NOTIFY)
834 fire_user_return_notifiers();
835
836#ifdef CONFIG_X86_32
837 clear_thread_flag(TIF_IRET);
838#endif /* CONFIG_X86_32 */
839}
840
841void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
842{
843 struct task_struct *me = current;
844
845 if (show_unhandled_signals && printk_ratelimit()) {
846 printk("%s"
847 "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
848 task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
849 me->comm, me->pid, where, frame,
850 regs->ip, regs->sp, regs->orig_ax);
851 print_vma_addr(" in ", regs->ip);
852 printk(KERN_CONT "\n");
853 }
854
855 force_sig(SIGSEGV, me);
856}