2 * linux/arch/i386/kernel/signal.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
6 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
7 * 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
10 #include <linux/sched.h>
12 #include <linux/smp.h>
13 #include <linux/kernel.h>
14 #include <linux/signal.h>
15 #include <linux/errno.h>
16 #include <linux/wait.h>
17 #include <linux/unistd.h>
18 #include <linux/stddef.h>
19 #include <linux/personality.h>
20 #include <linux/suspend.h>
21 #include <linux/ptrace.h>
22 #include <linux/elf.h>
23 #include <linux/binfmts.h>
24 #include <asm/processor.h>
25 #include <asm/ucontext.h>
26 #include <asm/uaccess.h>
32 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
35 * Atomically swap in the new signal mask, and wait for a signal.
38 sys_sigsuspend(int history0
, int history1
, old_sigset_t mask
)
41 spin_lock_irq(¤t
->sighand
->siglock
);
42 current
->saved_sigmask
= current
->blocked
;
43 siginitset(¤t
->blocked
, mask
);
45 spin_unlock_irq(¤t
->sighand
->siglock
);
47 current
->state
= TASK_INTERRUPTIBLE
;
49 set_thread_flag(TIF_RESTORE_SIGMASK
);
50 return -ERESTARTNOHAND
;
54 sys_sigaction(int sig
, const struct old_sigaction __user
*act
,
55 struct old_sigaction __user
*oact
)
57 struct k_sigaction new_ka
, old_ka
;
62 if (!access_ok(VERIFY_READ
, act
, sizeof(*act
)) ||
63 __get_user(new_ka
.sa
.sa_handler
, &act
->sa_handler
) ||
64 __get_user(new_ka
.sa
.sa_restorer
, &act
->sa_restorer
))
66 __get_user(new_ka
.sa
.sa_flags
, &act
->sa_flags
);
67 __get_user(mask
, &act
->sa_mask
);
68 siginitset(&new_ka
.sa
.sa_mask
, mask
);
71 ret
= do_sigaction(sig
, act
? &new_ka
: NULL
, oact
? &old_ka
: NULL
);
74 if (!access_ok(VERIFY_WRITE
, oact
, sizeof(*oact
)) ||
75 __put_user(old_ka
.sa
.sa_handler
, &oact
->sa_handler
) ||
76 __put_user(old_ka
.sa
.sa_restorer
, &oact
->sa_restorer
))
78 __put_user(old_ka
.sa
.sa_flags
, &oact
->sa_flags
);
79 __put_user(old_ka
.sa
.sa_mask
.sig
[0], &oact
->sa_mask
);
86 sys_sigaltstack(unsigned long ebx
)
88 /* This is needed to make gcc realize it doesn't own the "struct pt_regs" */
89 struct pt_regs
*regs
= (struct pt_regs
*)&ebx
;
90 const stack_t __user
*uss
= (const stack_t __user
*)ebx
;
91 stack_t __user
*uoss
= (stack_t __user
*)regs
->ecx
;
93 return do_sigaltstack(uss
, uoss
, regs
->esp
);
98 * Do a signal return; undo the signal stack.
102 restore_sigcontext(struct pt_regs
*regs
, struct sigcontext __user
*sc
, int *peax
)
104 unsigned int err
= 0;
106 /* Always make any pending restarted system calls return -EINTR */
107 current_thread_info()->restart_block
.fn
= do_no_restart_syscall
;
109 #define COPY(x) err |= __get_user(regs->x, &sc->x)
111 #define COPY_SEG(seg) \
112 { unsigned short tmp; \
113 err |= __get_user(tmp, &sc->seg); \
114 regs->x##seg = tmp; }
116 #define COPY_SEG_STRICT(seg) \
117 { unsigned short tmp; \
118 err |= __get_user(tmp, &sc->seg); \
119 regs->x##seg = tmp|3; }
121 #define GET_SEG(seg) \
122 { unsigned short tmp; \
123 err |= __get_user(tmp, &sc->seg); \
124 loadsegment(seg,tmp); }
126 #define FIX_EFLAGS (X86_EFLAGS_AC | X86_EFLAGS_RF | \
127 X86_EFLAGS_OF | X86_EFLAGS_DF | \
128 X86_EFLAGS_TF | X86_EFLAGS_SF | X86_EFLAGS_ZF | \
129 X86_EFLAGS_AF | X86_EFLAGS_PF | X86_EFLAGS_CF)
147 unsigned int tmpflags
;
148 err
|= __get_user(tmpflags
, &sc
->eflags
);
149 regs
->eflags
= (regs
->eflags
& ~FIX_EFLAGS
) | (tmpflags
& FIX_EFLAGS
);
150 regs
->orig_eax
= -1; /* disable syscall checks */
154 struct _fpstate __user
* buf
;
155 err
|= __get_user(buf
, &sc
->fpstate
);
157 if (!access_ok(VERIFY_READ
, buf
, sizeof(*buf
)))
159 err
|= restore_i387(buf
);
161 struct task_struct
*me
= current
;
169 err
|= __get_user(*peax
, &sc
->eax
);
176 asmlinkage
int sys_sigreturn(unsigned long __unused
)
178 struct pt_regs
*regs
= (struct pt_regs
*) &__unused
;
179 struct sigframe __user
*frame
= (struct sigframe __user
*)(regs
->esp
- 8);
183 if (!access_ok(VERIFY_READ
, frame
, sizeof(*frame
)))
185 if (__get_user(set
.sig
[0], &frame
->sc
.oldmask
)
187 && __copy_from_user(&set
.sig
[1], &frame
->extramask
,
188 sizeof(frame
->extramask
))))
191 sigdelsetmask(&set
, ~_BLOCKABLE
);
192 spin_lock_irq(¤t
->sighand
->siglock
);
193 current
->blocked
= set
;
195 spin_unlock_irq(¤t
->sighand
->siglock
);
197 if (restore_sigcontext(regs
, &frame
->sc
, &eax
))
202 if (show_unhandled_signals
&& printk_ratelimit())
203 printk("%s%s[%d] bad frame in sigreturn frame:%p eip:%lx"
204 " esp:%lx oeax:%lx\n",
205 current
->pid
> 1 ? KERN_INFO
: KERN_EMERG
,
206 current
->comm
, current
->pid
, frame
, regs
->eip
,
207 regs
->esp
, regs
->orig_eax
);
209 force_sig(SIGSEGV
, current
);
213 asmlinkage
int sys_rt_sigreturn(unsigned long __unused
)
215 struct pt_regs
*regs
= (struct pt_regs
*) &__unused
;
216 struct rt_sigframe __user
*frame
= (struct rt_sigframe __user
*)(regs
->esp
- 4);
220 if (!access_ok(VERIFY_READ
, frame
, sizeof(*frame
)))
222 if (__copy_from_user(&set
, &frame
->uc
.uc_sigmask
, sizeof(set
)))
225 sigdelsetmask(&set
, ~_BLOCKABLE
);
226 spin_lock_irq(¤t
->sighand
->siglock
);
227 current
->blocked
= set
;
229 spin_unlock_irq(¤t
->sighand
->siglock
);
231 if (restore_sigcontext(regs
, &frame
->uc
.uc_mcontext
, &eax
))
234 if (do_sigaltstack(&frame
->uc
.uc_stack
, NULL
, regs
->esp
) == -EFAULT
)
240 force_sig(SIGSEGV
, current
);
245 * Set up a signal frame.
249 setup_sigcontext(struct sigcontext __user
*sc
, struct _fpstate __user
*fpstate
,
250 struct pt_regs
*regs
, unsigned long mask
)
254 err
|= __put_user(regs
->xfs
, (unsigned int __user
*)&sc
->fs
);
255 savesegment(gs
, tmp
);
256 err
|= __put_user(tmp
, (unsigned int __user
*)&sc
->gs
);
258 err
|= __put_user(regs
->xes
, (unsigned int __user
*)&sc
->es
);
259 err
|= __put_user(regs
->xds
, (unsigned int __user
*)&sc
->ds
);
260 err
|= __put_user(regs
->edi
, &sc
->edi
);
261 err
|= __put_user(regs
->esi
, &sc
->esi
);
262 err
|= __put_user(regs
->ebp
, &sc
->ebp
);
263 err
|= __put_user(regs
->esp
, &sc
->esp
);
264 err
|= __put_user(regs
->ebx
, &sc
->ebx
);
265 err
|= __put_user(regs
->edx
, &sc
->edx
);
266 err
|= __put_user(regs
->ecx
, &sc
->ecx
);
267 err
|= __put_user(regs
->eax
, &sc
->eax
);
268 err
|= __put_user(current
->thread
.trap_no
, &sc
->trapno
);
269 err
|= __put_user(current
->thread
.error_code
, &sc
->err
);
270 err
|= __put_user(regs
->eip
, &sc
->eip
);
271 err
|= __put_user(regs
->xcs
, (unsigned int __user
*)&sc
->cs
);
272 err
|= __put_user(regs
->eflags
, &sc
->eflags
);
273 err
|= __put_user(regs
->esp
, &sc
->esp_at_signal
);
274 err
|= __put_user(regs
->xss
, (unsigned int __user
*)&sc
->ss
);
276 tmp
= save_i387(fpstate
);
280 err
|= __put_user(tmp
? fpstate
: NULL
, &sc
->fpstate
);
282 /* non-iBCS2 extensions.. */
283 err
|= __put_user(mask
, &sc
->oldmask
);
284 err
|= __put_user(current
->thread
.cr2
, &sc
->cr2
);
290 * Determine which stack to use..
292 static inline void __user
*
293 get_sigframe(struct k_sigaction
*ka
, struct pt_regs
* regs
, size_t frame_size
)
297 /* Default to using normal stack */
300 /* This is the X/Open sanctioned signal stack switching. */
301 if (ka
->sa
.sa_flags
& SA_ONSTACK
) {
302 if (sas_ss_flags(esp
) == 0)
303 esp
= current
->sas_ss_sp
+ current
->sas_ss_size
;
306 /* This is the legacy signal stack switching. */
307 else if ((regs
->xss
& 0xffff) != __USER_DS
&&
308 !(ka
->sa
.sa_flags
& SA_RESTORER
) &&
309 ka
->sa
.sa_restorer
) {
310 esp
= (unsigned long) ka
->sa
.sa_restorer
;
314 /* Align the stack pointer according to the i386 ABI,
315 * i.e. so that on function entry ((sp + 4) & 15) == 0. */
316 esp
= ((esp
+ 4) & -16ul) - 4;
317 return (void __user
*) esp
;
320 /* These symbols are defined with the addresses in the vsyscall page.
321 See vsyscall-sigreturn.S. */
322 extern void __user __kernel_sigreturn
;
323 extern void __user __kernel_rt_sigreturn
;
325 static int setup_frame(int sig
, struct k_sigaction
*ka
,
326 sigset_t
*set
, struct pt_regs
* regs
)
328 void __user
*restorer
;
329 struct sigframe __user
*frame
;
333 frame
= get_sigframe(ka
, regs
, sizeof(*frame
));
335 if (!access_ok(VERIFY_WRITE
, frame
, sizeof(*frame
)))
338 usig
= current_thread_info()->exec_domain
339 && current_thread_info()->exec_domain
->signal_invmap
341 ? current_thread_info()->exec_domain
->signal_invmap
[sig
]
344 err
= __put_user(usig
, &frame
->sig
);
348 err
= setup_sigcontext(&frame
->sc
, &frame
->fpstate
, regs
, set
->sig
[0]);
352 if (_NSIG_WORDS
> 1) {
353 err
= __copy_to_user(&frame
->extramask
, &set
->sig
[1],
354 sizeof(frame
->extramask
));
359 if (current
->binfmt
->hasvdso
)
360 restorer
= (void *)VDSO_SYM(&__kernel_sigreturn
);
362 restorer
= (void *)&frame
->retcode
;
363 if (ka
->sa
.sa_flags
& SA_RESTORER
)
364 restorer
= ka
->sa
.sa_restorer
;
366 /* Set up to return from userspace. */
367 err
|= __put_user(restorer
, &frame
->pretcode
);
370 * This is popl %eax ; movl $,%eax ; int $0x80
372 * WE DO NOT USE IT ANY MORE! It's only left here for historical
373 * reasons and because gdb uses it as a signature to notice
374 * signal handler stack frames.
376 err
|= __put_user(0xb858, (short __user
*)(frame
->retcode
+0));
377 err
|= __put_user(__NR_sigreturn
, (int __user
*)(frame
->retcode
+2));
378 err
|= __put_user(0x80cd, (short __user
*)(frame
->retcode
+6));
383 /* Set up registers for signal handler */
384 regs
->esp
= (unsigned long) frame
;
385 regs
->eip
= (unsigned long) ka
->sa
.sa_handler
;
386 regs
->eax
= (unsigned long) sig
;
387 regs
->edx
= (unsigned long) 0;
388 regs
->ecx
= (unsigned long) 0;
391 regs
->xds
= __USER_DS
;
392 regs
->xes
= __USER_DS
;
393 regs
->xss
= __USER_DS
;
394 regs
->xcs
= __USER_CS
;
397 * Clear TF when entering the signal handler, but
398 * notify any tracer that was single-stepping it.
399 * The tracer may want to single-step inside the
402 regs
->eflags
&= ~TF_MASK
;
403 if (test_thread_flag(TIF_SINGLESTEP
))
404 ptrace_notify(SIGTRAP
);
407 printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
408 current
->comm
, current
->pid
, frame
, regs
->eip
, frame
->pretcode
);
414 force_sigsegv(sig
, current
);
418 static int setup_rt_frame(int sig
, struct k_sigaction
*ka
, siginfo_t
*info
,
419 sigset_t
*set
, struct pt_regs
* regs
)
421 void __user
*restorer
;
422 struct rt_sigframe __user
*frame
;
426 frame
= get_sigframe(ka
, regs
, sizeof(*frame
));
428 if (!access_ok(VERIFY_WRITE
, frame
, sizeof(*frame
)))
431 usig
= current_thread_info()->exec_domain
432 && current_thread_info()->exec_domain
->signal_invmap
434 ? current_thread_info()->exec_domain
->signal_invmap
[sig
]
437 err
|= __put_user(usig
, &frame
->sig
);
438 err
|= __put_user(&frame
->info
, &frame
->pinfo
);
439 err
|= __put_user(&frame
->uc
, &frame
->puc
);
440 err
|= copy_siginfo_to_user(&frame
->info
, info
);
444 /* Create the ucontext. */
445 err
|= __put_user(0, &frame
->uc
.uc_flags
);
446 err
|= __put_user(0, &frame
->uc
.uc_link
);
447 err
|= __put_user(current
->sas_ss_sp
, &frame
->uc
.uc_stack
.ss_sp
);
448 err
|= __put_user(sas_ss_flags(regs
->esp
),
449 &frame
->uc
.uc_stack
.ss_flags
);
450 err
|= __put_user(current
->sas_ss_size
, &frame
->uc
.uc_stack
.ss_size
);
451 err
|= setup_sigcontext(&frame
->uc
.uc_mcontext
, &frame
->fpstate
,
453 err
|= __copy_to_user(&frame
->uc
.uc_sigmask
, set
, sizeof(*set
));
457 /* Set up to return from userspace. */
458 restorer
= (void *)VDSO_SYM(&__kernel_rt_sigreturn
);
459 if (ka
->sa
.sa_flags
& SA_RESTORER
)
460 restorer
= ka
->sa
.sa_restorer
;
461 err
|= __put_user(restorer
, &frame
->pretcode
);
464 * This is movl $,%eax ; int $0x80
466 * WE DO NOT USE IT ANY MORE! It's only left here for historical
467 * reasons and because gdb uses it as a signature to notice
468 * signal handler stack frames.
470 err
|= __put_user(0xb8, (char __user
*)(frame
->retcode
+0));
471 err
|= __put_user(__NR_rt_sigreturn
, (int __user
*)(frame
->retcode
+1));
472 err
|= __put_user(0x80cd, (short __user
*)(frame
->retcode
+5));
477 /* Set up registers for signal handler */
478 regs
->esp
= (unsigned long) frame
;
479 regs
->eip
= (unsigned long) ka
->sa
.sa_handler
;
480 regs
->eax
= (unsigned long) usig
;
481 regs
->edx
= (unsigned long) &frame
->info
;
482 regs
->ecx
= (unsigned long) &frame
->uc
;
485 regs
->xds
= __USER_DS
;
486 regs
->xes
= __USER_DS
;
487 regs
->xss
= __USER_DS
;
488 regs
->xcs
= __USER_CS
;
491 * Clear TF when entering the signal handler, but
492 * notify any tracer that was single-stepping it.
493 * The tracer may want to single-step inside the
496 regs
->eflags
&= ~TF_MASK
;
497 if (test_thread_flag(TIF_SINGLESTEP
))
498 ptrace_notify(SIGTRAP
);
501 printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
502 current
->comm
, current
->pid
, frame
, regs
->eip
, frame
->pretcode
);
508 force_sigsegv(sig
, current
);
513 * OK, we're invoking a handler
517 handle_signal(unsigned long sig
, siginfo_t
*info
, struct k_sigaction
*ka
,
518 sigset_t
*oldset
, struct pt_regs
* regs
)
522 /* Are we from a system call? */
523 if (regs
->orig_eax
>= 0) {
524 /* If so, check system call restarting.. */
526 case -ERESTART_RESTARTBLOCK
:
527 case -ERESTARTNOHAND
:
532 if (!(ka
->sa
.sa_flags
& SA_RESTART
)) {
537 case -ERESTARTNOINTR
:
538 regs
->eax
= regs
->orig_eax
;
544 * If TF is set due to a debugger (PT_DTRACE), clear the TF flag so
545 * that register information in the sigcontext is correct.
547 if (unlikely(regs
->eflags
& TF_MASK
)
548 && likely(current
->ptrace
& PT_DTRACE
)) {
549 current
->ptrace
&= ~PT_DTRACE
;
550 regs
->eflags
&= ~TF_MASK
;
553 /* Set up the stack frame */
554 if (ka
->sa
.sa_flags
& SA_SIGINFO
)
555 ret
= setup_rt_frame(sig
, ka
, info
, oldset
, regs
);
557 ret
= setup_frame(sig
, ka
, oldset
, regs
);
560 spin_lock_irq(¤t
->sighand
->siglock
);
561 sigorsets(¤t
->blocked
,¤t
->blocked
,&ka
->sa
.sa_mask
);
562 if (!(ka
->sa
.sa_flags
& SA_NODEFER
))
563 sigaddset(¤t
->blocked
,sig
);
565 spin_unlock_irq(¤t
->sighand
->siglock
);
572 * Note that 'init' is a special process: it doesn't get signals it doesn't
573 * want to handle. Thus you cannot kill init even with a SIGKILL even by
576 static void fastcall
do_signal(struct pt_regs
*regs
)
580 struct k_sigaction ka
;
584 * We want the common case to go fast, which
585 * is why we may in certain cases get here from
586 * kernel mode. Just return without doing anything
587 * if so. vm86 regs switched out by assembly code
588 * before reaching here, so testing against kernel
591 if (!user_mode(regs
))
594 if (test_thread_flag(TIF_RESTORE_SIGMASK
))
595 oldset
= ¤t
->saved_sigmask
;
597 oldset
= ¤t
->blocked
;
599 signr
= get_signal_to_deliver(&info
, &ka
, regs
, NULL
);
601 /* Reenable any watchpoints before delivering the
602 * signal to user space. The processor register will
603 * have been cleared if the watchpoint triggered
606 if (unlikely(current
->thread
.debugreg
[7]))
607 set_debugreg(current
->thread
.debugreg
[7], 7);
609 /* Whee! Actually deliver the signal. */
610 if (handle_signal(signr
, &info
, &ka
, oldset
, regs
) == 0) {
611 /* a signal was successfully delivered; the saved
612 * sigmask will have been stored in the signal frame,
613 * and will be restored by sigreturn, so we can simply
614 * clear the TIF_RESTORE_SIGMASK flag */
615 if (test_thread_flag(TIF_RESTORE_SIGMASK
))
616 clear_thread_flag(TIF_RESTORE_SIGMASK
);
622 /* Did we come from a system call? */
623 if (regs
->orig_eax
>= 0) {
624 /* Restart the system call - no handlers present */
626 case -ERESTARTNOHAND
:
628 case -ERESTARTNOINTR
:
629 regs
->eax
= regs
->orig_eax
;
633 case -ERESTART_RESTARTBLOCK
:
634 regs
->eax
= __NR_restart_syscall
;
640 /* if there's no signal to deliver, we just put the saved sigmask
642 if (test_thread_flag(TIF_RESTORE_SIGMASK
)) {
643 clear_thread_flag(TIF_RESTORE_SIGMASK
);
644 sigprocmask(SIG_SETMASK
, ¤t
->saved_sigmask
, NULL
);
649 * notification of userspace execution resumption
650 * - triggered by the TIF_WORK_MASK flags
652 __attribute__((regparm(3)))
653 void do_notify_resume(struct pt_regs
*regs
, void *_unused
,
654 __u32 thread_info_flags
)
656 /* Pending single-step? */
657 if (thread_info_flags
& _TIF_SINGLESTEP
) {
658 regs
->eflags
|= TF_MASK
;
659 clear_thread_flag(TIF_SINGLESTEP
);
662 /* deal with pending signal delivery */
663 if (thread_info_flags
& (_TIF_SIGPENDING
| _TIF_RESTORE_SIGMASK
))
666 clear_thread_flag(TIF_IRET
);