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>
31 #include <asm/syscalls.h>
34 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
36 #define __FIX_EFLAGS (X86_EFLAGS_AC | X86_EFLAGS_OF | \
37 X86_EFLAGS_DF | X86_EFLAGS_TF | X86_EFLAGS_SF | \
38 X86_EFLAGS_ZF | X86_EFLAGS_AF | X86_EFLAGS_PF | \
42 # define FIX_EFLAGS (__FIX_EFLAGS | X86_EFLAGS_RF)
44 # define FIX_EFLAGS __FIX_EFLAGS
47 int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
48 sigset_t *set, struct pt_regs * regs);
49 int ia32_setup_frame(int sig, struct k_sigaction *ka,
50 sigset_t *set, struct pt_regs * regs);
53 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
56 return do_sigaltstack(uss, uoss, regs->sp);
60 * Do a signal return; undo the signal stack.
63 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
68 /* Always make any pending restarted system calls return -EINTR */
69 current_thread_info()->restart_block.fn = do_no_restart_syscall;
71 #define COPY(x) err |= __get_user(regs->x, &sc->x)
73 COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
74 COPY(dx); COPY(cx); COPY(ip);
84 /* Kernel saves and restores only the CS segment register on signals,
85 * which is the bare minimum needed to allow mixed 32/64-bit code.
86 * App's signal handler can save/restore other segments if needed. */
89 err |= __get_user(cs, &sc->cs);
90 regs->cs = cs | 3; /* Force into user mode */
94 unsigned int tmpflags;
95 err |= __get_user(tmpflags, &sc->flags);
96 regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
97 regs->orig_ax = -1; /* disable syscall checks */
101 struct _fpstate __user * buf;
102 err |= __get_user(buf, &sc->fpstate);
103 err |= restore_i387_xstate(buf);
106 err |= __get_user(*pax, &sc->ax);
110 asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
112 struct rt_sigframe __user *frame;
116 frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
117 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
119 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
122 sigdelsetmask(&set, ~_BLOCKABLE);
123 spin_lock_irq(¤t->sighand->siglock);
124 current->blocked = set;
126 spin_unlock_irq(¤t->sighand->siglock);
128 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
131 if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
137 signal_fault(regs,frame,"sigreturn");
142 * Set up a signal frame.
146 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, unsigned long mask, struct task_struct *me)
150 err |= __put_user(regs->cs, &sc->cs);
151 err |= __put_user(0, &sc->gs);
152 err |= __put_user(0, &sc->fs);
154 err |= __put_user(regs->di, &sc->di);
155 err |= __put_user(regs->si, &sc->si);
156 err |= __put_user(regs->bp, &sc->bp);
157 err |= __put_user(regs->sp, &sc->sp);
158 err |= __put_user(regs->bx, &sc->bx);
159 err |= __put_user(regs->dx, &sc->dx);
160 err |= __put_user(regs->cx, &sc->cx);
161 err |= __put_user(regs->ax, &sc->ax);
162 err |= __put_user(regs->r8, &sc->r8);
163 err |= __put_user(regs->r9, &sc->r9);
164 err |= __put_user(regs->r10, &sc->r10);
165 err |= __put_user(regs->r11, &sc->r11);
166 err |= __put_user(regs->r12, &sc->r12);
167 err |= __put_user(regs->r13, &sc->r13);
168 err |= __put_user(regs->r14, &sc->r14);
169 err |= __put_user(regs->r15, &sc->r15);
170 err |= __put_user(me->thread.trap_no, &sc->trapno);
171 err |= __put_user(me->thread.error_code, &sc->err);
172 err |= __put_user(regs->ip, &sc->ip);
173 err |= __put_user(regs->flags, &sc->flags);
174 err |= __put_user(mask, &sc->oldmask);
175 err |= __put_user(me->thread.cr2, &sc->cr2);
181 * Determine which stack to use..
185 get_stack(struct k_sigaction *ka, struct pt_regs *regs, unsigned long size)
189 /* Default to using normal stack - redzone*/
192 /* This is the X/Open sanctioned signal stack switching. */
193 if (ka->sa.sa_flags & SA_ONSTACK) {
194 if (sas_ss_flags(sp) == 0)
195 sp = current->sas_ss_sp + current->sas_ss_size;
198 return (void __user *)round_down(sp - size, 64);
201 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
202 sigset_t *set, struct pt_regs * regs)
204 struct rt_sigframe __user *frame;
205 void __user *fp = NULL;
207 struct task_struct *me = current;
210 fp = get_stack(ka, regs, sig_xstate_size);
211 frame = (void __user *)round_down(
212 (unsigned long)fp - sizeof(struct rt_sigframe), 16) - 8;
214 if (save_i387_xstate(fp) < 0)
217 frame = get_stack(ka, regs, sizeof(struct rt_sigframe)) - 8;
219 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
222 if (ka->sa.sa_flags & SA_SIGINFO) {
223 err |= copy_siginfo_to_user(&frame->info, info);
228 /* Create the ucontext. */
230 err |= __put_user(UC_FP_XSTATE, &frame->uc.uc_flags);
232 err |= __put_user(0, &frame->uc.uc_flags);
233 err |= __put_user(0, &frame->uc.uc_link);
234 err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
235 err |= __put_user(sas_ss_flags(regs->sp),
236 &frame->uc.uc_stack.ss_flags);
237 err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
238 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0], me);
239 err |= __put_user(fp, &frame->uc.uc_mcontext.fpstate);
240 if (sizeof(*set) == 16) {
241 __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
242 __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
244 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
246 /* Set up to return from userspace. If provided, use a stub
247 already in userspace. */
248 /* x86-64 should always use SA_RESTORER. */
249 if (ka->sa.sa_flags & SA_RESTORER) {
250 err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
252 /* could use a vstub here */
259 /* Set up registers for signal handler */
261 /* In case the signal handler was declared without prototypes */
264 /* This also works for non SA_SIGINFO handlers because they expect the
265 next argument after the signal number on the stack. */
266 regs->si = (unsigned long)&frame->info;
267 regs->dx = (unsigned long)&frame->uc;
268 regs->ip = (unsigned long) ka->sa.sa_handler;
270 regs->sp = (unsigned long)frame;
272 /* Set up the CS register to run signal handlers in 64-bit mode,
273 even if the handler happens to be interrupting 32-bit code. */
274 regs->cs = __USER_CS;
279 force_sigsegv(sig, current);
284 * OK, we're invoking a handler
288 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
289 sigset_t *oldset, struct pt_regs *regs)
293 /* Are we from a system call? */
294 if (syscall_get_nr(current, regs) >= 0) {
295 /* If so, check system call restarting.. */
296 switch (syscall_get_error(current, regs)) {
297 case -ERESTART_RESTARTBLOCK:
298 case -ERESTARTNOHAND:
303 if (!(ka->sa.sa_flags & SA_RESTART)) {
308 case -ERESTARTNOINTR:
309 regs->ax = regs->orig_ax;
316 * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
317 * flag so that register information in the sigcontext is correct.
319 if (unlikely(regs->flags & X86_EFLAGS_TF) &&
320 likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
321 regs->flags &= ~X86_EFLAGS_TF;
323 #ifdef CONFIG_IA32_EMULATION
324 if (test_thread_flag(TIF_IA32)) {
325 if (ka->sa.sa_flags & SA_SIGINFO)
326 ret = ia32_setup_rt_frame(sig, ka, info, oldset, regs);
328 ret = ia32_setup_frame(sig, ka, oldset, regs);
331 ret = setup_rt_frame(sig, ka, info, oldset, regs);
335 * This has nothing to do with segment registers,
336 * despite the name. This magic affects uaccess.h
337 * macros' behavior. Reset it to the normal setting.
342 * Clear the direction flag as per the ABI for function entry.
344 regs->flags &= ~X86_EFLAGS_DF;
347 * Clear TF when entering the signal handler, but
348 * notify any tracer that was single-stepping it.
349 * The tracer may want to single-step inside the
352 regs->flags &= ~X86_EFLAGS_TF;
354 spin_lock_irq(¤t->sighand->siglock);
355 sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask);
356 if (!(ka->sa.sa_flags & SA_NODEFER))
357 sigaddset(¤t->blocked,sig);
359 spin_unlock_irq(¤t->sighand->siglock);
361 tracehook_signal_handler(sig, info, ka, regs,
362 test_thread_flag(TIF_SINGLESTEP));
369 * Note that 'init' is a special process: it doesn't get signals it doesn't
370 * want to handle. Thus you cannot kill init even with a SIGKILL even by
373 static void do_signal(struct pt_regs *regs)
375 struct k_sigaction ka;
381 * We want the common case to go fast, which is why we may in certain
382 * cases get here from kernel mode. Just return without doing anything
384 * X86_32: vm86 regs switched out by assembly code before reaching
385 * here, so testing against kernel CS suffices.
387 if (!user_mode(regs))
390 if (current_thread_info()->status & TS_RESTORE_SIGMASK)
391 oldset = ¤t->saved_sigmask;
393 oldset = ¤t->blocked;
395 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
397 /* Re-enable any watchpoints before delivering the
398 * signal to user space. The processor register will
399 * have been cleared if the watchpoint triggered
402 if (current->thread.debugreg7)
403 set_debugreg(current->thread.debugreg7, 7);
405 /* Whee! Actually deliver the signal. */
406 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
408 * A signal was successfully delivered; the saved
409 * sigmask will have been stored in the signal frame,
410 * and will be restored by sigreturn, so we can simply
411 * clear the TS_RESTORE_SIGMASK flag.
413 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
418 /* Did we come from a system call? */
419 if (syscall_get_nr(current, regs) >= 0) {
420 /* Restart the system call - no handlers present */
421 switch (syscall_get_error(current, regs)) {
422 case -ERESTARTNOHAND:
424 case -ERESTARTNOINTR:
425 regs->ax = regs->orig_ax;
428 case -ERESTART_RESTARTBLOCK:
429 regs->ax = test_thread_flag(TIF_IA32) ?
430 __NR_ia32_restart_syscall :
431 __NR_restart_syscall;
438 * If there's no signal to deliver, we just put the saved sigmask
441 if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
442 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
443 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
447 void do_notify_resume(struct pt_regs *regs, void *unused,
448 __u32 thread_info_flags)
450 #ifdef CONFIG_X86_MCE
451 /* notify userspace of pending MCEs */
452 if (thread_info_flags & _TIF_MCE_NOTIFY)
454 #endif /* CONFIG_X86_MCE */
456 /* deal with pending signal delivery */
457 if (thread_info_flags & _TIF_SIGPENDING)
460 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
461 clear_thread_flag(TIF_NOTIFY_RESUME);
462 tracehook_notify_resume(regs);
466 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
468 struct task_struct *me = current;
469 if (show_unhandled_signals && printk_ratelimit()) {
470 printk("%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
471 me->comm,me->pid,where,frame,regs->ip,regs->sp,regs->orig_ax);
472 print_vma_addr(" in ", regs->ip);
476 force_sig(SIGSEGV, me);