2 * Copyright (C) 1991, 1992 Linus Torvalds
3 * Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
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
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/ptrace.h>
18 #include <linux/unistd.h>
19 #include <linux/stddef.h>
20 #include <linux/personality.h>
21 #include <linux/compiler.h>
22 #include <asm/processor.h>
23 #include <asm/ucontext.h>
24 #include <asm/uaccess.h>
26 #include <asm/proto.h>
27 #include <asm/ia32_unistd.h>
29 #include <asm/syscalls.h>
32 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
34 #define __FIX_EFLAGS (X86_EFLAGS_AC | X86_EFLAGS_OF | \
35 X86_EFLAGS_DF | X86_EFLAGS_TF | X86_EFLAGS_SF | \
36 X86_EFLAGS_ZF | X86_EFLAGS_AF | X86_EFLAGS_PF | \
40 # define FIX_EFLAGS (__FIX_EFLAGS | X86_EFLAGS_RF)
42 # define FIX_EFLAGS __FIX_EFLAGS
45 int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
46 sigset_t *set, struct pt_regs * regs);
47 int ia32_setup_frame(int sig, struct k_sigaction *ka,
48 sigset_t *set, struct pt_regs * regs);
51 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
54 return do_sigaltstack(uss, uoss, regs->sp);
58 * Signal frame handlers.
61 static inline int save_i387(struct _fpstate __user *buf)
63 struct task_struct *tsk = current;
66 BUILD_BUG_ON(sizeof(struct user_i387_struct) !=
67 sizeof(tsk->thread.xstate->fxsave));
69 if ((unsigned long)buf % 16)
70 printk("save_i387: bad fpstate %p\n", buf);
74 clear_used_math(); /* trigger finit */
75 if (task_thread_info(tsk)->status & TS_USEDFPU) {
76 err = save_i387_checking((struct i387_fxsave_struct __user *)
80 task_thread_info(tsk)->status &= ~TS_USEDFPU;
83 if (__copy_to_user(buf, &tsk->thread.xstate->fxsave,
84 sizeof(struct i387_fxsave_struct)))
91 * This restores directly out of user space. Exceptions are handled.
93 static inline int restore_i387(struct _fpstate __user *buf)
95 struct task_struct *tsk = current;
104 if (!(task_thread_info(current)->status & TS_USEDFPU)) {
106 task_thread_info(current)->status |= TS_USEDFPU;
108 err = restore_fpu_checking((__force struct i387_fxsave_struct *)buf);
111 * Encountered an error while doing the restore from the
112 * user buffer, clear the fpu state.
121 * Do a signal return; undo the signal stack.
124 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
127 unsigned int err = 0;
129 /* Always make any pending restarted system calls return -EINTR */
130 current_thread_info()->restart_block.fn = do_no_restart_syscall;
132 #define COPY(x) err |= __get_user(regs->x, &sc->x)
134 COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
135 COPY(dx); COPY(cx); COPY(ip);
145 /* Kernel saves and restores only the CS segment register on signals,
146 * which is the bare minimum needed to allow mixed 32/64-bit code.
147 * App's signal handler can save/restore other segments if needed. */
150 err |= __get_user(cs, &sc->cs);
151 regs->cs = cs | 3; /* Force into user mode */
155 unsigned int tmpflags;
156 err |= __get_user(tmpflags, &sc->flags);
157 regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
158 regs->orig_ax = -1; /* disable syscall checks */
162 struct _fpstate __user * buf;
163 err |= __get_user(buf, &sc->fpstate);
166 if (!access_ok(VERIFY_READ, buf, sizeof(*buf)))
168 err |= restore_i387(buf);
170 struct task_struct *me = current;
178 err |= __get_user(*pax, &sc->ax);
185 asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
187 struct rt_sigframe __user *frame;
191 frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
192 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
194 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
197 sigdelsetmask(&set, ~_BLOCKABLE);
198 spin_lock_irq(¤t->sighand->siglock);
199 current->blocked = set;
201 spin_unlock_irq(¤t->sighand->siglock);
203 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
206 if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
212 signal_fault(regs,frame,"sigreturn");
217 * Set up a signal frame.
221 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, unsigned long mask, struct task_struct *me)
225 err |= __put_user(regs->cs, &sc->cs);
226 err |= __put_user(0, &sc->gs);
227 err |= __put_user(0, &sc->fs);
229 err |= __put_user(regs->di, &sc->di);
230 err |= __put_user(regs->si, &sc->si);
231 err |= __put_user(regs->bp, &sc->bp);
232 err |= __put_user(regs->sp, &sc->sp);
233 err |= __put_user(regs->bx, &sc->bx);
234 err |= __put_user(regs->dx, &sc->dx);
235 err |= __put_user(regs->cx, &sc->cx);
236 err |= __put_user(regs->ax, &sc->ax);
237 err |= __put_user(regs->r8, &sc->r8);
238 err |= __put_user(regs->r9, &sc->r9);
239 err |= __put_user(regs->r10, &sc->r10);
240 err |= __put_user(regs->r11, &sc->r11);
241 err |= __put_user(regs->r12, &sc->r12);
242 err |= __put_user(regs->r13, &sc->r13);
243 err |= __put_user(regs->r14, &sc->r14);
244 err |= __put_user(regs->r15, &sc->r15);
245 err |= __put_user(me->thread.trap_no, &sc->trapno);
246 err |= __put_user(me->thread.error_code, &sc->err);
247 err |= __put_user(regs->ip, &sc->ip);
248 err |= __put_user(regs->flags, &sc->flags);
249 err |= __put_user(mask, &sc->oldmask);
250 err |= __put_user(me->thread.cr2, &sc->cr2);
256 * Determine which stack to use..
260 get_stack(struct k_sigaction *ka, struct pt_regs *regs, unsigned long size)
264 /* Default to using normal stack - redzone*/
267 /* This is the X/Open sanctioned signal stack switching. */
268 if (ka->sa.sa_flags & SA_ONSTACK) {
269 if (sas_ss_flags(sp) == 0)
270 sp = current->sas_ss_sp + current->sas_ss_size;
273 return (void __user *)round_down(sp - size, 16);
276 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
277 sigset_t *set, struct pt_regs * regs)
279 struct rt_sigframe __user *frame;
280 struct _fpstate __user *fp = NULL;
282 struct task_struct *me = current;
285 fp = get_stack(ka, regs, sizeof(struct _fpstate));
286 frame = (void __user *)round_down(
287 (unsigned long)fp - sizeof(struct rt_sigframe), 16) - 8;
289 if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate)))
292 if (save_i387(fp) < 0)
295 frame = get_stack(ka, regs, sizeof(struct rt_sigframe)) - 8;
297 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
300 if (ka->sa.sa_flags & SA_SIGINFO) {
301 err |= copy_siginfo_to_user(&frame->info, info);
306 /* Create the ucontext. */
307 err |= __put_user(0, &frame->uc.uc_flags);
308 err |= __put_user(0, &frame->uc.uc_link);
309 err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
310 err |= __put_user(sas_ss_flags(regs->sp),
311 &frame->uc.uc_stack.ss_flags);
312 err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
313 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0], me);
314 err |= __put_user(fp, &frame->uc.uc_mcontext.fpstate);
315 if (sizeof(*set) == 16) {
316 __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
317 __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
319 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
321 /* Set up to return from userspace. If provided, use a stub
322 already in userspace. */
323 /* x86-64 should always use SA_RESTORER. */
324 if (ka->sa.sa_flags & SA_RESTORER) {
325 err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
327 /* could use a vstub here */
334 /* Set up registers for signal handler */
336 /* In case the signal handler was declared without prototypes */
339 /* This also works for non SA_SIGINFO handlers because they expect the
340 next argument after the signal number on the stack. */
341 regs->si = (unsigned long)&frame->info;
342 regs->dx = (unsigned long)&frame->uc;
343 regs->ip = (unsigned long) ka->sa.sa_handler;
345 regs->sp = (unsigned long)frame;
347 /* Set up the CS register to run signal handlers in 64-bit mode,
348 even if the handler happens to be interrupting 32-bit code. */
349 regs->cs = __USER_CS;
354 force_sigsegv(sig, current);
359 * Return -1L or the syscall number that @regs is executing.
361 static long current_syscall(struct pt_regs *regs)
364 * We always sign-extend a -1 value being set here,
365 * so this is always either -1L or a syscall number.
367 return regs->orig_ax;
371 * Return a value that is -EFOO if the system call in @regs->orig_ax
372 * returned an error. This only works for @regs from @current.
374 static long current_syscall_ret(struct pt_regs *regs)
376 #ifdef CONFIG_IA32_EMULATION
377 if (test_thread_flag(TIF_IA32))
379 * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
380 * and will match correctly in comparisons.
382 return (int) regs->ax;
388 * OK, we're invoking a handler
392 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
393 sigset_t *oldset, struct pt_regs *regs)
397 /* Are we from a system call? */
398 if (current_syscall(regs) >= 0) {
399 /* If so, check system call restarting.. */
400 switch (current_syscall_ret(regs)) {
401 case -ERESTART_RESTARTBLOCK:
402 case -ERESTARTNOHAND:
407 if (!(ka->sa.sa_flags & SA_RESTART)) {
412 case -ERESTARTNOINTR:
413 regs->ax = regs->orig_ax;
420 * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
421 * flag so that register information in the sigcontext is correct.
423 if (unlikely(regs->flags & X86_EFLAGS_TF) &&
424 likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
425 regs->flags &= ~X86_EFLAGS_TF;
427 #ifdef CONFIG_IA32_EMULATION
428 if (test_thread_flag(TIF_IA32)) {
429 if (ka->sa.sa_flags & SA_SIGINFO)
430 ret = ia32_setup_rt_frame(sig, ka, info, oldset, regs);
432 ret = ia32_setup_frame(sig, ka, oldset, regs);
435 ret = setup_rt_frame(sig, ka, info, oldset, regs);
439 * This has nothing to do with segment registers,
440 * despite the name. This magic affects uaccess.h
441 * macros' behavior. Reset it to the normal setting.
446 * Clear the direction flag as per the ABI for function entry.
448 regs->flags &= ~X86_EFLAGS_DF;
451 * Clear TF when entering the signal handler, but
452 * notify any tracer that was single-stepping it.
453 * The tracer may want to single-step inside the
456 regs->flags &= ~X86_EFLAGS_TF;
457 if (test_thread_flag(TIF_SINGLESTEP))
458 ptrace_notify(SIGTRAP);
460 spin_lock_irq(¤t->sighand->siglock);
461 sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask);
462 if (!(ka->sa.sa_flags & SA_NODEFER))
463 sigaddset(¤t->blocked,sig);
465 spin_unlock_irq(¤t->sighand->siglock);
472 * Note that 'init' is a special process: it doesn't get signals it doesn't
473 * want to handle. Thus you cannot kill init even with a SIGKILL even by
476 static void do_signal(struct pt_regs *regs)
478 struct k_sigaction ka;
484 * We want the common case to go fast, which is why we may in certain
485 * cases get here from kernel mode. Just return without doing anything
487 * X86_32: vm86 regs switched out by assembly code before reaching
488 * here, so testing against kernel CS suffices.
490 if (!user_mode(regs))
493 if (current_thread_info()->status & TS_RESTORE_SIGMASK)
494 oldset = ¤t->saved_sigmask;
496 oldset = ¤t->blocked;
498 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
500 /* Re-enable any watchpoints before delivering the
501 * signal to user space. The processor register will
502 * have been cleared if the watchpoint triggered
505 if (current->thread.debugreg7)
506 set_debugreg(current->thread.debugreg7, 7);
508 /* Whee! Actually deliver the signal. */
509 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
511 * A signal was successfully delivered; the saved
512 * sigmask will have been stored in the signal frame,
513 * and will be restored by sigreturn, so we can simply
514 * clear the TS_RESTORE_SIGMASK flag.
516 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
521 /* Did we come from a system call? */
522 if (current_syscall(regs) >= 0) {
523 /* Restart the system call - no handlers present */
524 switch (current_syscall_ret(regs)) {
525 case -ERESTARTNOHAND:
527 case -ERESTARTNOINTR:
528 regs->ax = regs->orig_ax;
531 case -ERESTART_RESTARTBLOCK:
532 regs->ax = test_thread_flag(TIF_IA32) ?
533 __NR_ia32_restart_syscall :
534 __NR_restart_syscall;
541 * If there's no signal to deliver, we just put the saved sigmask
544 if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
545 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
546 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
550 void do_notify_resume(struct pt_regs *regs, void *unused,
551 __u32 thread_info_flags)
553 #ifdef CONFIG_X86_MCE
554 /* notify userspace of pending MCEs */
555 if (thread_info_flags & _TIF_MCE_NOTIFY)
557 #endif /* CONFIG_X86_MCE */
559 /* deal with pending signal delivery */
560 if (thread_info_flags & _TIF_SIGPENDING)
564 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
566 struct task_struct *me = current;
567 if (show_unhandled_signals && printk_ratelimit()) {
568 printk("%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
569 me->comm,me->pid,where,frame,regs->ip,regs->sp,regs->orig_ax);
570 print_vma_addr(" in ", regs->ip);
574 force_sig(SIGSEGV, me);