| /* | |
| * linux/arch/alpha/kernel/signal.c | |
| * | |
| * Copyright (C) 1995 Linus Torvalds | |
| * | |
| * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson | |
| */ | |
| #include <linux/sched.h> | |
| #include <linux/kernel.h> | |
| #include <linux/signal.h> | |
| #include <linux/errno.h> | |
| #include <linux/wait.h> | |
| #include <linux/ptrace.h> | |
| #include <linux/unistd.h> | |
| #include <linux/mm.h> | |
| #include <linux/smp.h> | |
| #include <linux/stddef.h> | |
| #include <linux/tty.h> | |
| #include <linux/binfmts.h> | |
| #include <linux/bitops.h> | |
| #include <asm/uaccess.h> | |
| #include <asm/sigcontext.h> | |
| #include <asm/ucontext.h> | |
| #include "proto.h" | |
| #define DEBUG_SIG 0 | |
| #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) | |
| asmlinkage void ret_from_sys_call(void); | |
| static void do_signal(struct pt_regs *, struct switch_stack *, | |
| unsigned long, unsigned long); | |
| /* | |
| * The OSF/1 sigprocmask calling sequence is different from the | |
| * C sigprocmask() sequence.. | |
| * | |
| * how: | |
| * 1 - SIG_BLOCK | |
| * 2 - SIG_UNBLOCK | |
| * 3 - SIG_SETMASK | |
| * | |
| * We change the range to -1 .. 1 in order to let gcc easily | |
| * use the conditional move instructions. | |
| * | |
| * Note that we don't need to acquire the kernel lock for SMP | |
| * operation, as all of this is local to this thread. | |
| */ | |
| asmlinkage unsigned long | |
| do_osf_sigprocmask(int how, unsigned long newmask, struct pt_regs *regs) | |
| { | |
| unsigned long oldmask = -EINVAL; | |
| if ((unsigned long)how-1 <= 2) { | |
| long sign = how-2; /* -1 .. 1 */ | |
| unsigned long block, unblock; | |
| newmask &= _BLOCKABLE; | |
| spin_lock_irq(¤t->sighand->siglock); | |
| oldmask = current->blocked.sig[0]; | |
| unblock = oldmask & ~newmask; | |
| block = oldmask | newmask; | |
| if (!sign) | |
| block = unblock; | |
| if (sign <= 0) | |
| newmask = block; | |
| if (_NSIG_WORDS > 1 && sign > 0) | |
| sigemptyset(¤t->blocked); | |
| current->blocked.sig[0] = newmask; | |
| recalc_sigpending(); | |
| spin_unlock_irq(¤t->sighand->siglock); | |
| regs->r0 = 0; /* special no error return */ | |
| } | |
| return oldmask; | |
| } | |
| asmlinkage int | |
| osf_sigaction(int sig, const struct osf_sigaction __user *act, | |
| struct osf_sigaction __user *oact) | |
| { | |
| struct k_sigaction new_ka, old_ka; | |
| int ret; | |
| if (act) { | |
| old_sigset_t mask; | |
| if (!access_ok(VERIFY_READ, act, sizeof(*act)) || | |
| __get_user(new_ka.sa.sa_handler, &act->sa_handler) || | |
| __get_user(new_ka.sa.sa_flags, &act->sa_flags)) | |
| return -EFAULT; | |
| __get_user(mask, &act->sa_mask); | |
| siginitset(&new_ka.sa.sa_mask, mask); | |
| new_ka.ka_restorer = NULL; | |
| } | |
| ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
| if (!ret && oact) { | |
| if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || | |
| __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || | |
| __put_user(old_ka.sa.sa_flags, &oact->sa_flags)) | |
| return -EFAULT; | |
| __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask); | |
| } | |
| return ret; | |
| } | |
| asmlinkage long | |
| sys_rt_sigaction(int sig, const struct sigaction __user *act, | |
| struct sigaction __user *oact, | |
| size_t sigsetsize, void __user *restorer) | |
| { | |
| struct k_sigaction new_ka, old_ka; | |
| int ret; | |
| /* XXX: Don't preclude handling different sized sigset_t's. */ | |
| if (sigsetsize != sizeof(sigset_t)) | |
| return -EINVAL; | |
| if (act) { | |
| new_ka.ka_restorer = restorer; | |
| if (copy_from_user(&new_ka.sa, act, sizeof(*act))) | |
| return -EFAULT; | |
| } | |
| ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
| if (!ret && oact) { | |
| if (copy_to_user(oact, &old_ka.sa, sizeof(*oact))) | |
| return -EFAULT; | |
| } | |
| return ret; | |
| } | |
| /* | |
| * Atomically swap in the new signal mask, and wait for a signal. | |
| */ | |
| asmlinkage int | |
| do_sigsuspend(old_sigset_t mask, struct pt_regs *regs, struct switch_stack *sw) | |
| { | |
| mask &= _BLOCKABLE; | |
| spin_lock_irq(¤t->sighand->siglock); | |
| current->saved_sigmask = current->blocked; | |
| siginitset(¤t->blocked, mask); | |
| recalc_sigpending(); | |
| spin_unlock_irq(¤t->sighand->siglock); | |
| /* Indicate EINTR on return from any possible signal handler, | |
| which will not come back through here, but via sigreturn. */ | |
| regs->r0 = EINTR; | |
| regs->r19 = 1; | |
| current->state = TASK_INTERRUPTIBLE; | |
| schedule(); | |
| set_thread_flag(TIF_RESTORE_SIGMASK); | |
| return -ERESTARTNOHAND; | |
| } | |
| asmlinkage int | |
| do_rt_sigsuspend(sigset_t __user *uset, size_t sigsetsize, | |
| struct pt_regs *regs, struct switch_stack *sw) | |
| { | |
| sigset_t set; | |
| /* XXX: Don't preclude handling different sized sigset_t's. */ | |
| if (sigsetsize != sizeof(sigset_t)) | |
| return -EINVAL; | |
| if (copy_from_user(&set, uset, sizeof(set))) | |
| return -EFAULT; | |
| sigdelsetmask(&set, ~_BLOCKABLE); | |
| spin_lock_irq(¤t->sighand->siglock); | |
| current->saved_sigmask = current->blocked; | |
| current->blocked = set; | |
| recalc_sigpending(); | |
| spin_unlock_irq(¤t->sighand->siglock); | |
| /* Indicate EINTR on return from any possible signal handler, | |
| which will not come back through here, but via sigreturn. */ | |
| regs->r0 = EINTR; | |
| regs->r19 = 1; | |
| current->state = TASK_INTERRUPTIBLE; | |
| schedule(); | |
| set_thread_flag(TIF_RESTORE_SIGMASK); | |
| return -ERESTARTNOHAND; | |
| } | |
| asmlinkage int | |
| sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss) | |
| { | |
| return do_sigaltstack(uss, uoss, rdusp()); | |
| } | |
| /* | |
| * Do a signal return; undo the signal stack. | |
| */ | |
| #if _NSIG_WORDS > 1 | |
| # error "Non SA_SIGINFO frame needs rearranging" | |
| #endif | |
| struct sigframe | |
| { | |
| struct sigcontext sc; | |
| unsigned int retcode[3]; | |
| }; | |
| struct rt_sigframe | |
| { | |
| struct siginfo info; | |
| struct ucontext uc; | |
| unsigned int retcode[3]; | |
| }; | |
| /* If this changes, userland unwinders that Know Things about our signal | |
| frame will break. Do not undertake lightly. It also implies an ABI | |
| change wrt the size of siginfo_t, which may cause some pain. */ | |
| extern char compile_time_assert | |
| [offsetof(struct rt_sigframe, uc.uc_mcontext) == 176 ? 1 : -1]; | |
| #define INSN_MOV_R30_R16 0x47fe0410 | |
| #define INSN_LDI_R0 0x201f0000 | |
| #define INSN_CALLSYS 0x00000083 | |
| static long | |
| restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, | |
| struct switch_stack *sw) | |
| { | |
| unsigned long usp; | |
| long i, err = __get_user(regs->pc, &sc->sc_pc); | |
| sw->r26 = (unsigned long) ret_from_sys_call; | |
| err |= __get_user(regs->r0, sc->sc_regs+0); | |
| err |= __get_user(regs->r1, sc->sc_regs+1); | |
| err |= __get_user(regs->r2, sc->sc_regs+2); | |
| err |= __get_user(regs->r3, sc->sc_regs+3); | |
| err |= __get_user(regs->r4, sc->sc_regs+4); | |
| err |= __get_user(regs->r5, sc->sc_regs+5); | |
| err |= __get_user(regs->r6, sc->sc_regs+6); | |
| err |= __get_user(regs->r7, sc->sc_regs+7); | |
| err |= __get_user(regs->r8, sc->sc_regs+8); | |
| err |= __get_user(sw->r9, sc->sc_regs+9); | |
| err |= __get_user(sw->r10, sc->sc_regs+10); | |
| err |= __get_user(sw->r11, sc->sc_regs+11); | |
| err |= __get_user(sw->r12, sc->sc_regs+12); | |
| err |= __get_user(sw->r13, sc->sc_regs+13); | |
| err |= __get_user(sw->r14, sc->sc_regs+14); | |
| err |= __get_user(sw->r15, sc->sc_regs+15); | |
| err |= __get_user(regs->r16, sc->sc_regs+16); | |
| err |= __get_user(regs->r17, sc->sc_regs+17); | |
| err |= __get_user(regs->r18, sc->sc_regs+18); | |
| err |= __get_user(regs->r19, sc->sc_regs+19); | |
| err |= __get_user(regs->r20, sc->sc_regs+20); | |
| err |= __get_user(regs->r21, sc->sc_regs+21); | |
| err |= __get_user(regs->r22, sc->sc_regs+22); | |
| err |= __get_user(regs->r23, sc->sc_regs+23); | |
| err |= __get_user(regs->r24, sc->sc_regs+24); | |
| err |= __get_user(regs->r25, sc->sc_regs+25); | |
| err |= __get_user(regs->r26, sc->sc_regs+26); | |
| err |= __get_user(regs->r27, sc->sc_regs+27); | |
| err |= __get_user(regs->r28, sc->sc_regs+28); | |
| err |= __get_user(regs->gp, sc->sc_regs+29); | |
| err |= __get_user(usp, sc->sc_regs+30); | |
| wrusp(usp); | |
| for (i = 0; i < 31; i++) | |
| err |= __get_user(sw->fp[i], sc->sc_fpregs+i); | |
| err |= __get_user(sw->fp[31], &sc->sc_fpcr); | |
| return err; | |
| } | |
| /* Note that this syscall is also used by setcontext(3) to install | |
| a given sigcontext. This because it's impossible to set *all* | |
| registers and transfer control from userland. */ | |
| asmlinkage void | |
| do_sigreturn(struct sigcontext __user *sc, struct pt_regs *regs, | |
| struct switch_stack *sw) | |
| { | |
| sigset_t set; | |
| /* Verify that it's a good sigcontext before using it */ | |
| if (!access_ok(VERIFY_READ, sc, sizeof(*sc))) | |
| goto give_sigsegv; | |
| if (__get_user(set.sig[0], &sc->sc_mask)) | |
| goto give_sigsegv; | |
| sigdelsetmask(&set, ~_BLOCKABLE); | |
| spin_lock_irq(¤t->sighand->siglock); | |
| current->blocked = set; | |
| recalc_sigpending(); | |
| spin_unlock_irq(¤t->sighand->siglock); | |
| if (restore_sigcontext(sc, regs, sw)) | |
| goto give_sigsegv; | |
| /* Send SIGTRAP if we're single-stepping: */ | |
| if (ptrace_cancel_bpt (current)) { | |
| siginfo_t info; | |
| info.si_signo = SIGTRAP; | |
| info.si_errno = 0; | |
| info.si_code = TRAP_BRKPT; | |
| info.si_addr = (void __user *) regs->pc; | |
| info.si_trapno = 0; | |
| send_sig_info(SIGTRAP, &info, current); | |
| } | |
| return; | |
| give_sigsegv: | |
| force_sig(SIGSEGV, current); | |
| } | |
| asmlinkage void | |
| do_rt_sigreturn(struct rt_sigframe __user *frame, struct pt_regs *regs, | |
| struct switch_stack *sw) | |
| { | |
| sigset_t set; | |
| /* Verify that it's a good ucontext_t before using it */ | |
| if (!access_ok(VERIFY_READ, &frame->uc, sizeof(frame->uc))) | |
| goto give_sigsegv; | |
| if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) | |
| goto give_sigsegv; | |
| sigdelsetmask(&set, ~_BLOCKABLE); | |
| spin_lock_irq(¤t->sighand->siglock); | |
| current->blocked = set; | |
| recalc_sigpending(); | |
| spin_unlock_irq(¤t->sighand->siglock); | |
| if (restore_sigcontext(&frame->uc.uc_mcontext, regs, sw)) | |
| goto give_sigsegv; | |
| /* Send SIGTRAP if we're single-stepping: */ | |
| if (ptrace_cancel_bpt (current)) { | |
| siginfo_t info; | |
| info.si_signo = SIGTRAP; | |
| info.si_errno = 0; | |
| info.si_code = TRAP_BRKPT; | |
| info.si_addr = (void __user *) regs->pc; | |
| info.si_trapno = 0; | |
| send_sig_info(SIGTRAP, &info, current); | |
| } | |
| return; | |
| give_sigsegv: | |
| force_sig(SIGSEGV, current); | |
| } | |
| /* | |
| * Set up a signal frame. | |
| */ | |
| static inline void __user * | |
| get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size) | |
| { | |
| if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp)) | |
| sp = current->sas_ss_sp + current->sas_ss_size; | |
| return (void __user *)((sp - frame_size) & -32ul); | |
| } | |
| static long | |
| setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, | |
| struct switch_stack *sw, unsigned long mask, unsigned long sp) | |
| { | |
| long i, err = 0; | |
| err |= __put_user(on_sig_stack((unsigned long)sc), &sc->sc_onstack); | |
| err |= __put_user(mask, &sc->sc_mask); | |
| err |= __put_user(regs->pc, &sc->sc_pc); | |
| err |= __put_user(8, &sc->sc_ps); | |
| err |= __put_user(regs->r0 , sc->sc_regs+0); | |
| err |= __put_user(regs->r1 , sc->sc_regs+1); | |
| err |= __put_user(regs->r2 , sc->sc_regs+2); | |
| err |= __put_user(regs->r3 , sc->sc_regs+3); | |
| err |= __put_user(regs->r4 , sc->sc_regs+4); | |
| err |= __put_user(regs->r5 , sc->sc_regs+5); | |
| err |= __put_user(regs->r6 , sc->sc_regs+6); | |
| err |= __put_user(regs->r7 , sc->sc_regs+7); | |
| err |= __put_user(regs->r8 , sc->sc_regs+8); | |
| err |= __put_user(sw->r9 , sc->sc_regs+9); | |
| err |= __put_user(sw->r10 , sc->sc_regs+10); | |
| err |= __put_user(sw->r11 , sc->sc_regs+11); | |
| err |= __put_user(sw->r12 , sc->sc_regs+12); | |
| err |= __put_user(sw->r13 , sc->sc_regs+13); | |
| err |= __put_user(sw->r14 , sc->sc_regs+14); | |
| err |= __put_user(sw->r15 , sc->sc_regs+15); | |
| err |= __put_user(regs->r16, sc->sc_regs+16); | |
| err |= __put_user(regs->r17, sc->sc_regs+17); | |
| err |= __put_user(regs->r18, sc->sc_regs+18); | |
| err |= __put_user(regs->r19, sc->sc_regs+19); | |
| err |= __put_user(regs->r20, sc->sc_regs+20); | |
| err |= __put_user(regs->r21, sc->sc_regs+21); | |
| err |= __put_user(regs->r22, sc->sc_regs+22); | |
| err |= __put_user(regs->r23, sc->sc_regs+23); | |
| err |= __put_user(regs->r24, sc->sc_regs+24); | |
| err |= __put_user(regs->r25, sc->sc_regs+25); | |
| err |= __put_user(regs->r26, sc->sc_regs+26); | |
| err |= __put_user(regs->r27, sc->sc_regs+27); | |
| err |= __put_user(regs->r28, sc->sc_regs+28); | |
| err |= __put_user(regs->gp , sc->sc_regs+29); | |
| err |= __put_user(sp, sc->sc_regs+30); | |
| err |= __put_user(0, sc->sc_regs+31); | |
| for (i = 0; i < 31; i++) | |
| err |= __put_user(sw->fp[i], sc->sc_fpregs+i); | |
| err |= __put_user(0, sc->sc_fpregs+31); | |
| err |= __put_user(sw->fp[31], &sc->sc_fpcr); | |
| err |= __put_user(regs->trap_a0, &sc->sc_traparg_a0); | |
| err |= __put_user(regs->trap_a1, &sc->sc_traparg_a1); | |
| err |= __put_user(regs->trap_a2, &sc->sc_traparg_a2); | |
| return err; | |
| } | |
| static int | |
| setup_frame(int sig, struct k_sigaction *ka, sigset_t *set, | |
| struct pt_regs *regs, struct switch_stack * sw) | |
| { | |
| unsigned long oldsp, r26, err = 0; | |
| struct sigframe __user *frame; | |
| oldsp = rdusp(); | |
| frame = get_sigframe(ka, oldsp, sizeof(*frame)); | |
| if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) | |
| goto give_sigsegv; | |
| err |= setup_sigcontext(&frame->sc, regs, sw, set->sig[0], oldsp); | |
| if (err) | |
| goto give_sigsegv; | |
| /* Set up to return from userspace. If provided, use a stub | |
| already in userspace. */ | |
| if (ka->ka_restorer) { | |
| r26 = (unsigned long) ka->ka_restorer; | |
| } else { | |
| err |= __put_user(INSN_MOV_R30_R16, frame->retcode+0); | |
| err |= __put_user(INSN_LDI_R0+__NR_sigreturn, frame->retcode+1); | |
| err |= __put_user(INSN_CALLSYS, frame->retcode+2); | |
| imb(); | |
| r26 = (unsigned long) frame->retcode; | |
| } | |
| /* Check that everything was written properly. */ | |
| if (err) | |
| goto give_sigsegv; | |
| /* "Return" to the handler */ | |
| regs->r26 = r26; | |
| regs->r27 = regs->pc = (unsigned long) ka->sa.sa_handler; | |
| regs->r16 = sig; /* a0: signal number */ | |
| regs->r17 = 0; /* a1: exception code */ | |
| regs->r18 = (unsigned long) &frame->sc; /* a2: sigcontext pointer */ | |
| wrusp((unsigned long) frame); | |
| #if DEBUG_SIG | |
| printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n", | |
| current->comm, current->pid, frame, regs->pc, regs->r26); | |
| #endif | |
| return 0; | |
| give_sigsegv: | |
| force_sigsegv(sig, current); | |
| return -EFAULT; | |
| } | |
| static int | |
| setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, | |
| sigset_t *set, struct pt_regs *regs, struct switch_stack * sw) | |
| { | |
| unsigned long oldsp, r26, err = 0; | |
| struct rt_sigframe __user *frame; | |
| oldsp = rdusp(); | |
| frame = get_sigframe(ka, oldsp, sizeof(*frame)); | |
| if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) | |
| goto give_sigsegv; | |
| err |= copy_siginfo_to_user(&frame->info, info); | |
| /* Create the ucontext. */ | |
| err |= __put_user(0, &frame->uc.uc_flags); | |
| err |= __put_user(0, &frame->uc.uc_link); | |
| err |= __put_user(set->sig[0], &frame->uc.uc_osf_sigmask); | |
| err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp); | |
| err |= __put_user(sas_ss_flags(oldsp), &frame->uc.uc_stack.ss_flags); | |
| err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size); | |
| err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, sw, | |
| set->sig[0], oldsp); | |
| err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); | |
| if (err) | |
| goto give_sigsegv; | |
| /* Set up to return from userspace. If provided, use a stub | |
| already in userspace. */ | |
| if (ka->ka_restorer) { | |
| r26 = (unsigned long) ka->ka_restorer; | |
| } else { | |
| err |= __put_user(INSN_MOV_R30_R16, frame->retcode+0); | |
| err |= __put_user(INSN_LDI_R0+__NR_rt_sigreturn, | |
| frame->retcode+1); | |
| err |= __put_user(INSN_CALLSYS, frame->retcode+2); | |
| imb(); | |
| r26 = (unsigned long) frame->retcode; | |
| } | |
| if (err) | |
| goto give_sigsegv; | |
| /* "Return" to the handler */ | |
| regs->r26 = r26; | |
| regs->r27 = regs->pc = (unsigned long) ka->sa.sa_handler; | |
| regs->r16 = sig; /* a0: signal number */ | |
| regs->r17 = (unsigned long) &frame->info; /* a1: siginfo pointer */ | |
| regs->r18 = (unsigned long) &frame->uc; /* a2: ucontext pointer */ | |
| wrusp((unsigned long) frame); | |
| #if DEBUG_SIG | |
| printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n", | |
| current->comm, current->pid, frame, regs->pc, regs->r26); | |
| #endif | |
| return 0; | |
| give_sigsegv: | |
| force_sigsegv(sig, current); | |
| return -EFAULT; | |
| } | |
| /* | |
| * OK, we're invoking a handler. | |
| */ | |
| static inline int | |
| handle_signal(int sig, struct k_sigaction *ka, siginfo_t *info, | |
| sigset_t *oldset, struct pt_regs * regs, struct switch_stack *sw) | |
| { | |
| int ret; | |
| if (ka->sa.sa_flags & SA_SIGINFO) | |
| ret = setup_rt_frame(sig, ka, info, oldset, regs, sw); | |
| else | |
| ret = setup_frame(sig, ka, oldset, regs, sw); | |
| if (ret == 0) { | |
| spin_lock_irq(¤t->sighand->siglock); | |
| sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask); | |
| if (!(ka->sa.sa_flags & SA_NODEFER)) | |
| sigaddset(¤t->blocked,sig); | |
| recalc_sigpending(); | |
| spin_unlock_irq(¤t->sighand->siglock); | |
| } | |
| return ret; | |
| } | |
| static inline void | |
| syscall_restart(unsigned long r0, unsigned long r19, | |
| struct pt_regs *regs, struct k_sigaction *ka) | |
| { | |
| switch (regs->r0) { | |
| case ERESTARTSYS: | |
| if (!(ka->sa.sa_flags & SA_RESTART)) { | |
| case ERESTARTNOHAND: | |
| regs->r0 = EINTR; | |
| break; | |
| } | |
| /* fallthrough */ | |
| case ERESTARTNOINTR: | |
| regs->r0 = r0; /* reset v0 and a3 and replay syscall */ | |
| regs->r19 = r19; | |
| regs->pc -= 4; | |
| break; | |
| case ERESTART_RESTARTBLOCK: | |
| current_thread_info()->restart_block.fn = do_no_restart_syscall; | |
| regs->r0 = EINTR; | |
| break; | |
| } | |
| } | |
| /* | |
| * Note that 'init' is a special process: it doesn't get signals it doesn't | |
| * want to handle. Thus you cannot kill init even with a SIGKILL even by | |
| * mistake. | |
| * | |
| * Note that we go through the signals twice: once to check the signals that | |
| * the kernel can handle, and then we build all the user-level signal handling | |
| * stack-frames in one go after that. | |
| * | |
| * "r0" and "r19" are the registers we need to restore for system call | |
| * restart. "r0" is also used as an indicator whether we can restart at | |
| * all (if we get here from anything but a syscall return, it will be 0) | |
| */ | |
| static void | |
| do_signal(struct pt_regs * regs, struct switch_stack * sw, | |
| unsigned long r0, unsigned long r19) | |
| { | |
| siginfo_t info; | |
| int signr; | |
| unsigned long single_stepping = ptrace_cancel_bpt(current); | |
| struct k_sigaction ka; | |
| sigset_t *oldset; | |
| if (test_thread_flag(TIF_RESTORE_SIGMASK)) | |
| oldset = ¤t->saved_sigmask; | |
| else | |
| oldset = ¤t->blocked; | |
| /* This lets the debugger run, ... */ | |
| signr = get_signal_to_deliver(&info, &ka, regs, NULL); | |
| /* ... so re-check the single stepping. */ | |
| single_stepping |= ptrace_cancel_bpt(current); | |
| if (signr > 0) { | |
| /* Whee! Actually deliver the signal. */ | |
| if (r0) | |
| syscall_restart(r0, r19, regs, &ka); | |
| if (handle_signal(signr, &ka, &info, oldset, regs, sw) == 0) { | |
| /* A signal was successfully delivered, and the | |
| saved sigmask was stored on the signal frame, | |
| and will be restored by sigreturn. So we can | |
| simply clear the restore sigmask flag. */ | |
| if (test_thread_flag(TIF_RESTORE_SIGMASK)) | |
| clear_thread_flag(TIF_RESTORE_SIGMASK); | |
| } | |
| if (single_stepping) | |
| ptrace_set_bpt(current); /* re-set bpt */ | |
| return; | |
| } | |
| if (r0) { | |
| switch (regs->r0) { | |
| case ERESTARTNOHAND: | |
| case ERESTARTSYS: | |
| case ERESTARTNOINTR: | |
| /* Reset v0 and a3 and replay syscall. */ | |
| regs->r0 = r0; | |
| regs->r19 = r19; | |
| regs->pc -= 4; | |
| break; | |
| case ERESTART_RESTARTBLOCK: | |
| /* Force v0 to the restart syscall and reply. */ | |
| regs->r0 = __NR_restart_syscall; | |
| regs->pc -= 4; | |
| break; | |
| } | |
| } | |
| /* If there's no signal to deliver, we just restore the saved mask. */ | |
| if (test_thread_flag(TIF_RESTORE_SIGMASK)) { | |
| clear_thread_flag(TIF_RESTORE_SIGMASK); | |
| sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); | |
| } | |
| if (single_stepping) | |
| ptrace_set_bpt(current); /* re-set breakpoint */ | |
| } | |
| void | |
| do_notify_resume(struct pt_regs *regs, struct switch_stack *sw, | |
| unsigned long thread_info_flags, | |
| unsigned long r0, unsigned long r19) | |
| { | |
| if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK)) | |
| do_signal(regs, sw, r0, r19); | |
| } |