/* * 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); }