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/tracehook.h>
19 #include <linux/unistd.h>
20 #include <linux/stddef.h>
21 #include <linux/personality.h>
22 #include <linux/compiler.h>
23 #include <asm/processor.h>
24 #include <asm/ucontext.h>
25 #include <asm/uaccess.h>
27 #include <asm/proto.h>
28 #include <asm/ia32_unistd.h>
30 #include <asm/syscall.h>
33 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
35 #define __FIX_EFLAGS (X86_EFLAGS_AC | X86_EFLAGS_OF | \
36 X86_EFLAGS_DF | X86_EFLAGS_TF | X86_EFLAGS_SF | \
37 X86_EFLAGS_ZF | X86_EFLAGS_AF | X86_EFLAGS_PF | \
41 # define FIX_EFLAGS (__FIX_EFLAGS | X86_EFLAGS_RF)
43 # define FIX_EFLAGS __FIX_EFLAGS
46 int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
47 sigset_t *set, struct pt_regs * regs);
48 int ia32_setup_frame(int sig, struct k_sigaction *ka,
49 sigset_t *set, struct pt_regs * regs);
52 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
55 return do_sigaltstack(uss, uoss, regs->sp);
59 * Signal frame handlers.
62 static inline int save_i387(struct _fpstate __user *buf)
64 struct task_struct *tsk = current;
67 BUILD_BUG_ON(sizeof(struct user_i387_struct) !=
68 sizeof(tsk->thread.xstate->fxsave));
70 if ((unsigned long)buf % 16)
71 printk("save_i387: bad fpstate %p\n", buf);
75 clear_used_math(); /* trigger finit */
76 if (task_thread_info(tsk)->status & TS_USEDFPU) {
77 err = save_i387_checking((struct i387_fxsave_struct __user *)
81 task_thread_info(tsk)->status &= ~TS_USEDFPU;
84 if (__copy_to_user(buf, &tsk->thread.xstate->fxsave,
85 sizeof(struct i387_fxsave_struct)))
92 * This restores directly out of user space. Exceptions are handled.
94 static inline int restore_i387(struct _fpstate __user *buf)
96 struct task_struct *tsk = current;
105 if (!(task_thread_info(current)->status & TS_USEDFPU)) {
107 task_thread_info(current)->status |= TS_USEDFPU;
109 err = restore_fpu_checking((__force struct i387_fxsave_struct *)buf);
112 * Encountered an error while doing the restore from the
113 * user buffer, clear the fpu state.
122 * Do a signal return; undo the signal stack.
125 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
128 unsigned int err = 0;
130 /* Always make any pending restarted system calls return -EINTR */
131 current_thread_info()->restart_block.fn = do_no_restart_syscall;
133 #define COPY(x) err |= __get_user(regs->x, &sc->x)
135 COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
136 COPY(dx); COPY(cx); COPY(ip);
146 /* Kernel saves and restores only the CS segment register on signals,
147 * which is the bare minimum needed to allow mixed 32/64-bit code.
148 * App's signal handler can save/restore other segments if needed. */
151 err |= __get_user(cs, &sc->cs);
152 regs->cs = cs | 3; /* Force into user mode */
156 unsigned int tmpflags;
157 err |= __get_user(tmpflags, &sc->flags);
158 regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
159 regs->orig_ax = -1; /* disable syscall checks */
163 struct _fpstate __user * buf;
164 err |= __get_user(buf, &sc->fpstate);
167 if (!access_ok(VERIFY_READ, buf, sizeof(*buf)))
169 err |= restore_i387(buf);
171 struct task_struct *me = current;
179 err |= __get_user(*pax, &sc->ax);
186 asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
188 struct rt_sigframe __user *frame;
192 frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
193 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
195 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
198 sigdelsetmask(&set, ~_BLOCKABLE);
199 spin_lock_irq(¤t->sighand->siglock);
200 current->blocked = set;
202 spin_unlock_irq(¤t->sighand->siglock);
204 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
207 if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
213 signal_fault(regs,frame,"sigreturn");
218 * Set up a signal frame.
222 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, unsigned long mask, struct task_struct *me)
226 err |= __put_user(regs->cs, &sc->cs);
227 err |= __put_user(0, &sc->gs);
228 err |= __put_user(0, &sc->fs);
230 err |= __put_user(regs->di, &sc->di);
231 err |= __put_user(regs->si, &sc->si);
232 err |= __put_user(regs->bp, &sc->bp);
233 err |= __put_user(regs->sp, &sc->sp);
234 err |= __put_user(regs->bx, &sc->bx);
235 err |= __put_user(regs->dx, &sc->dx);
236 err |= __put_user(regs->cx, &sc->cx);
237 err |= __put_user(regs->ax, &sc->ax);
238 err |= __put_user(regs->r8, &sc->r8);
239 err |= __put_user(regs->r9, &sc->r9);
240 err |= __put_user(regs->r10, &sc->r10);
241 err |= __put_user(regs->r11, &sc->r11);
242 err |= __put_user(regs->r12, &sc->r12);
243 err |= __put_user(regs->r13, &sc->r13);
244 err |= __put_user(regs->r14, &sc->r14);
245 err |= __put_user(regs->r15, &sc->r15);
246 err |= __put_user(me->thread.trap_no, &sc->trapno);
247 err |= __put_user(me->thread.error_code, &sc->err);
248 err |= __put_user(regs->ip, &sc->ip);
249 err |= __put_user(regs->flags, &sc->flags);
250 err |= __put_user(mask, &sc->oldmask);
251 err |= __put_user(me->thread.cr2, &sc->cr2);
257 * Determine which stack to use..
261 get_stack(struct k_sigaction *ka, struct pt_regs *regs, unsigned long size)
265 /* Default to using normal stack - redzone*/
268 /* This is the X/Open sanctioned signal stack switching. */
269 if (ka->sa.sa_flags & SA_ONSTACK) {
270 if (sas_ss_flags(sp) == 0)
271 sp = current->sas_ss_sp + current->sas_ss_size;
274 return (void __user *)round_down(sp - size, 16);
277 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
278 sigset_t *set, struct pt_regs * regs)
280 struct rt_sigframe __user *frame;
281 struct _fpstate __user *fp = NULL;
283 struct task_struct *me = current;
286 fp = get_stack(ka, regs, sizeof(struct _fpstate));
287 frame = (void __user *)round_down(
288 (unsigned long)fp - sizeof(struct rt_sigframe), 16) - 8;
290 if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate)))
293 if (save_i387(fp) < 0)
296 frame = get_stack(ka, regs, sizeof(struct rt_sigframe)) - 8;
298 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
301 if (ka->sa.sa_flags & SA_SIGINFO) {
302 err |= copy_siginfo_to_user(&frame->info, info);
307 /* Create the ucontext. */
308 err |= __put_user(0, &frame->uc.uc_flags);
309 err |= __put_user(0, &frame->uc.uc_link);
310 err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
311 err |= __put_user(sas_ss_flags(regs->sp),
312 &frame->uc.uc_stack.ss_flags);
313 err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
314 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0], me);
315 err |= __put_user(fp, &frame->uc.uc_mcontext.fpstate);
316 if (sizeof(*set) == 16) {
317 __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
318 __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
320 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
322 /* Set up to return from userspace. If provided, use a stub
323 already in userspace. */
324 /* x86-64 should always use SA_RESTORER. */
325 if (ka->sa.sa_flags & SA_RESTORER) {
326 err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
328 /* could use a vstub here */
335 /* Set up registers for signal handler */
337 /* In case the signal handler was declared without prototypes */
340 /* This also works for non SA_SIGINFO handlers because they expect the
341 next argument after the signal number on the stack. */
342 regs->si = (unsigned long)&frame->info;
343 regs->dx = (unsigned long)&frame->uc;
344 regs->ip = (unsigned long) ka->sa.sa_handler;
346 regs->sp = (unsigned long)frame;
348 /* Set up the CS register to run signal handlers in 64-bit mode,
349 even if the handler happens to be interrupting 32-bit code. */
350 regs->cs = __USER_CS;
355 force_sigsegv(sig, current);
360 * OK, we're invoking a handler
364 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
365 sigset_t *oldset, struct pt_regs *regs)
369 /* Are we from a system call? */
370 if (syscall_get_nr(current, regs) >= 0) {
371 /* If so, check system call restarting.. */
372 switch (syscall_get_error(current, regs)) {
373 case -ERESTART_RESTARTBLOCK:
374 case -ERESTARTNOHAND:
379 if (!(ka->sa.sa_flags & SA_RESTART)) {
384 case -ERESTARTNOINTR:
385 regs->ax = regs->orig_ax;
392 * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
393 * flag so that register information in the sigcontext is correct.
395 if (unlikely(regs->flags & X86_EFLAGS_TF) &&
396 likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
397 regs->flags &= ~X86_EFLAGS_TF;
399 #ifdef CONFIG_IA32_EMULATION
400 if (test_thread_flag(TIF_IA32)) {
401 if (ka->sa.sa_flags & SA_SIGINFO)
402 ret = ia32_setup_rt_frame(sig, ka, info, oldset, regs);
404 ret = ia32_setup_frame(sig, ka, oldset, regs);
407 ret = setup_rt_frame(sig, ka, info, oldset, regs);
411 * This has nothing to do with segment registers,
412 * despite the name. This magic affects uaccess.h
413 * macros' behavior. Reset it to the normal setting.
418 * Clear the direction flag as per the ABI for function entry.
420 regs->flags &= ~X86_EFLAGS_DF;
423 * Clear TF when entering the signal handler, but
424 * notify any tracer that was single-stepping it.
425 * The tracer may want to single-step inside the
428 regs->flags &= ~X86_EFLAGS_TF;
430 spin_lock_irq(¤t->sighand->siglock);
431 sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask);
432 if (!(ka->sa.sa_flags & SA_NODEFER))
433 sigaddset(¤t->blocked,sig);
435 spin_unlock_irq(¤t->sighand->siglock);
437 tracehook_signal_handler(sig, info, ka, regs,
438 test_thread_flag(TIF_SINGLESTEP));
445 * Note that 'init' is a special process: it doesn't get signals it doesn't
446 * want to handle. Thus you cannot kill init even with a SIGKILL even by
449 static void do_signal(struct pt_regs *regs)
451 struct k_sigaction ka;
457 * We want the common case to go fast, which is why we may in certain
458 * cases get here from kernel mode. Just return without doing anything
460 * X86_32: vm86 regs switched out by assembly code before reaching
461 * here, so testing against kernel CS suffices.
463 if (!user_mode(regs))
466 if (current_thread_info()->status & TS_RESTORE_SIGMASK)
467 oldset = ¤t->saved_sigmask;
469 oldset = ¤t->blocked;
471 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
473 /* Re-enable any watchpoints before delivering the
474 * signal to user space. The processor register will
475 * have been cleared if the watchpoint triggered
478 if (current->thread.debugreg7)
479 set_debugreg(current->thread.debugreg7, 7);
481 /* Whee! Actually deliver the signal. */
482 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
484 * A signal was successfully delivered; the saved
485 * sigmask will have been stored in the signal frame,
486 * and will be restored by sigreturn, so we can simply
487 * clear the TS_RESTORE_SIGMASK flag.
489 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
494 /* Did we come from a system call? */
495 if (syscall_get_nr(current, regs) >= 0) {
496 /* Restart the system call - no handlers present */
497 switch (syscall_get_error(current, regs)) {
498 case -ERESTARTNOHAND:
500 case -ERESTARTNOINTR:
501 regs->ax = regs->orig_ax;
504 case -ERESTART_RESTARTBLOCK:
505 regs->ax = test_thread_flag(TIF_IA32) ?
506 __NR_ia32_restart_syscall :
507 __NR_restart_syscall;
514 * If there's no signal to deliver, we just put the saved sigmask
517 if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
518 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
519 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
523 void do_notify_resume(struct pt_regs *regs, void *unused,
524 __u32 thread_info_flags)
526 #ifdef CONFIG_X86_MCE
527 /* notify userspace of pending MCEs */
528 if (thread_info_flags & _TIF_MCE_NOTIFY)
530 #endif /* CONFIG_X86_MCE */
532 /* deal with pending signal delivery */
533 if (thread_info_flags & _TIF_SIGPENDING)
536 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
537 clear_thread_flag(TIF_NOTIFY_RESUME);
538 tracehook_notify_resume(regs);
542 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
544 struct task_struct *me = current;
545 if (show_unhandled_signals && printk_ratelimit()) {
546 printk("%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
547 me->comm,me->pid,where,frame,regs->ip,regs->sp,regs->orig_ax);
548 print_vma_addr(" in ", regs->ip);
552 force_sig(SIGSEGV, me);