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 return restore_fpu_checking((__force struct i387_fxsave_struct *)buf);
112 * Do a signal return; undo the signal stack.
115 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
118 unsigned int err = 0;
120 /* Always make any pending restarted system calls return -EINTR */
121 current_thread_info()->restart_block.fn = do_no_restart_syscall;
123 #define COPY(x) err |= __get_user(regs->x, &sc->x)
125 COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
126 COPY(dx); COPY(cx); COPY(ip);
136 /* Kernel saves and restores only the CS segment register on signals,
137 * which is the bare minimum needed to allow mixed 32/64-bit code.
138 * App's signal handler can save/restore other segments if needed. */
141 err |= __get_user(cs, &sc->cs);
142 regs->cs = cs | 3; /* Force into user mode */
146 unsigned int tmpflags;
147 err |= __get_user(tmpflags, &sc->flags);
148 regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
149 regs->orig_ax = -1; /* disable syscall checks */
153 struct _fpstate __user * buf;
154 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(*pax, &sc->ax);
176 asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
178 struct rt_sigframe __user *frame;
182 frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
183 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
185 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
188 sigdelsetmask(&set, ~_BLOCKABLE);
189 spin_lock_irq(¤t->sighand->siglock);
190 current->blocked = set;
192 spin_unlock_irq(¤t->sighand->siglock);
194 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
197 if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
203 signal_fault(regs,frame,"sigreturn");
208 * Set up a signal frame.
212 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, unsigned long mask, struct task_struct *me)
216 err |= __put_user(regs->cs, &sc->cs);
217 err |= __put_user(0, &sc->gs);
218 err |= __put_user(0, &sc->fs);
220 err |= __put_user(regs->di, &sc->di);
221 err |= __put_user(regs->si, &sc->si);
222 err |= __put_user(regs->bp, &sc->bp);
223 err |= __put_user(regs->sp, &sc->sp);
224 err |= __put_user(regs->bx, &sc->bx);
225 err |= __put_user(regs->dx, &sc->dx);
226 err |= __put_user(regs->cx, &sc->cx);
227 err |= __put_user(regs->ax, &sc->ax);
228 err |= __put_user(regs->r8, &sc->r8);
229 err |= __put_user(regs->r9, &sc->r9);
230 err |= __put_user(regs->r10, &sc->r10);
231 err |= __put_user(regs->r11, &sc->r11);
232 err |= __put_user(regs->r12, &sc->r12);
233 err |= __put_user(regs->r13, &sc->r13);
234 err |= __put_user(regs->r14, &sc->r14);
235 err |= __put_user(regs->r15, &sc->r15);
236 err |= __put_user(me->thread.trap_no, &sc->trapno);
237 err |= __put_user(me->thread.error_code, &sc->err);
238 err |= __put_user(regs->ip, &sc->ip);
239 err |= __put_user(regs->flags, &sc->flags);
240 err |= __put_user(mask, &sc->oldmask);
241 err |= __put_user(me->thread.cr2, &sc->cr2);
247 * Determine which stack to use..
251 get_stack(struct k_sigaction *ka, struct pt_regs *regs, unsigned long size)
255 /* Default to using normal stack - redzone*/
258 /* This is the X/Open sanctioned signal stack switching. */
259 if (ka->sa.sa_flags & SA_ONSTACK) {
260 if (sas_ss_flags(sp) == 0)
261 sp = current->sas_ss_sp + current->sas_ss_size;
264 return (void __user *)round_down(sp - size, 16);
267 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
268 sigset_t *set, struct pt_regs * regs)
270 struct rt_sigframe __user *frame;
271 struct _fpstate __user *fp = NULL;
273 struct task_struct *me = current;
276 fp = get_stack(ka, regs, sizeof(struct _fpstate));
277 frame = (void __user *)round_down(
278 (unsigned long)fp - sizeof(struct rt_sigframe), 16) - 8;
280 if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate)))
283 if (save_i387(fp) < 0)
286 frame = get_stack(ka, regs, sizeof(struct rt_sigframe)) - 8;
288 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
291 if (ka->sa.sa_flags & SA_SIGINFO) {
292 err |= copy_siginfo_to_user(&frame->info, info);
297 /* Create the ucontext. */
298 err |= __put_user(0, &frame->uc.uc_flags);
299 err |= __put_user(0, &frame->uc.uc_link);
300 err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
301 err |= __put_user(sas_ss_flags(regs->sp),
302 &frame->uc.uc_stack.ss_flags);
303 err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
304 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0], me);
305 err |= __put_user(fp, &frame->uc.uc_mcontext.fpstate);
306 if (sizeof(*set) == 16) {
307 __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
308 __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
310 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
312 /* Set up to return from userspace. If provided, use a stub
313 already in userspace. */
314 /* x86-64 should always use SA_RESTORER. */
315 if (ka->sa.sa_flags & SA_RESTORER) {
316 err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
318 /* could use a vstub here */
325 /* Set up registers for signal handler */
327 /* In case the signal handler was declared without prototypes */
330 /* This also works for non SA_SIGINFO handlers because they expect the
331 next argument after the signal number on the stack. */
332 regs->si = (unsigned long)&frame->info;
333 regs->dx = (unsigned long)&frame->uc;
334 regs->ip = (unsigned long) ka->sa.sa_handler;
336 regs->sp = (unsigned long)frame;
338 /* Set up the CS register to run signal handlers in 64-bit mode,
339 even if the handler happens to be interrupting 32-bit code. */
340 regs->cs = __USER_CS;
345 force_sigsegv(sig, current);
350 * Return -1L or the syscall number that @regs is executing.
352 static long current_syscall(struct pt_regs *regs)
355 * We always sign-extend a -1 value being set here,
356 * so this is always either -1L or a syscall number.
358 return regs->orig_ax;
362 * Return a value that is -EFOO if the system call in @regs->orig_ax
363 * returned an error. This only works for @regs from @current.
365 static long current_syscall_ret(struct pt_regs *regs)
367 #ifdef CONFIG_IA32_EMULATION
368 if (test_thread_flag(TIF_IA32))
370 * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
371 * and will match correctly in comparisons.
373 return (int) regs->ax;
379 * OK, we're invoking a handler
383 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
384 sigset_t *oldset, struct pt_regs *regs)
388 /* Are we from a system call? */
389 if (current_syscall(regs) >= 0) {
390 /* If so, check system call restarting.. */
391 switch (current_syscall_ret(regs)) {
392 case -ERESTART_RESTARTBLOCK:
393 case -ERESTARTNOHAND:
398 if (!(ka->sa.sa_flags & SA_RESTART)) {
403 case -ERESTARTNOINTR:
404 regs->ax = regs->orig_ax;
411 * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
412 * flag so that register information in the sigcontext is correct.
414 if (unlikely(regs->flags & X86_EFLAGS_TF) &&
415 likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
416 regs->flags &= ~X86_EFLAGS_TF;
418 #ifdef CONFIG_IA32_EMULATION
419 if (test_thread_flag(TIF_IA32)) {
420 if (ka->sa.sa_flags & SA_SIGINFO)
421 ret = ia32_setup_rt_frame(sig, ka, info, oldset, regs);
423 ret = ia32_setup_frame(sig, ka, oldset, regs);
426 ret = setup_rt_frame(sig, ka, info, oldset, regs);
430 * This has nothing to do with segment registers,
431 * despite the name. This magic affects uaccess.h
432 * macros' behavior. Reset it to the normal setting.
437 * Clear the direction flag as per the ABI for function entry.
439 regs->flags &= ~X86_EFLAGS_DF;
442 * Clear TF when entering the signal handler, but
443 * notify any tracer that was single-stepping it.
444 * The tracer may want to single-step inside the
447 regs->flags &= ~X86_EFLAGS_TF;
448 if (test_thread_flag(TIF_SINGLESTEP))
449 ptrace_notify(SIGTRAP);
451 spin_lock_irq(¤t->sighand->siglock);
452 sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask);
453 if (!(ka->sa.sa_flags & SA_NODEFER))
454 sigaddset(¤t->blocked,sig);
456 spin_unlock_irq(¤t->sighand->siglock);
463 * Note that 'init' is a special process: it doesn't get signals it doesn't
464 * want to handle. Thus you cannot kill init even with a SIGKILL even by
467 static void do_signal(struct pt_regs *regs)
469 struct k_sigaction ka;
475 * We want the common case to go fast, which is why we may in certain
476 * cases get here from kernel mode. Just return without doing anything
478 * X86_32: vm86 regs switched out by assembly code before reaching
479 * here, so testing against kernel CS suffices.
481 if (!user_mode(regs))
484 if (current_thread_info()->status & TS_RESTORE_SIGMASK)
485 oldset = ¤t->saved_sigmask;
487 oldset = ¤t->blocked;
489 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
491 /* Re-enable any watchpoints before delivering the
492 * signal to user space. The processor register will
493 * have been cleared if the watchpoint triggered
496 if (current->thread.debugreg7)
497 set_debugreg(current->thread.debugreg7, 7);
499 /* Whee! Actually deliver the signal. */
500 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
502 * A signal was successfully delivered; the saved
503 * sigmask will have been stored in the signal frame,
504 * and will be restored by sigreturn, so we can simply
505 * clear the TS_RESTORE_SIGMASK flag.
507 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
512 /* Did we come from a system call? */
513 if (current_syscall(regs) >= 0) {
514 /* Restart the system call - no handlers present */
515 switch (current_syscall_ret(regs)) {
516 case -ERESTARTNOHAND:
518 case -ERESTARTNOINTR:
519 regs->ax = regs->orig_ax;
522 case -ERESTART_RESTARTBLOCK:
523 regs->ax = test_thread_flag(TIF_IA32) ?
524 __NR_ia32_restart_syscall :
525 __NR_restart_syscall;
532 * If there's no signal to deliver, we just put the saved sigmask
535 if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
536 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
537 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
541 void do_notify_resume(struct pt_regs *regs, void *unused,
542 __u32 thread_info_flags)
544 #ifdef CONFIG_X86_MCE
545 /* notify userspace of pending MCEs */
546 if (thread_info_flags & _TIF_MCE_NOTIFY)
548 #endif /* CONFIG_X86_MCE */
550 /* deal with pending signal delivery */
551 if (thread_info_flags & _TIF_SIGPENDING)
555 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
557 struct task_struct *me = current;
558 if (show_unhandled_signals && printk_ratelimit()) {
559 printk("%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
560 me->comm,me->pid,where,frame,regs->ip,regs->sp,regs->orig_ax);
561 print_vma_addr(" in ", regs->ip);
565 force_sig(SIGSEGV, me);