LXR linux/arch/um/kernel/signal.c

   1/*
   2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3 * Licensed under the GPL
   4 */
   5
   6#include <linux/module.h>
   7#include <linux/ptrace.h>
   8#include <linux/sched.h>
   9#include <asm/siginfo.h>
  10#include <asm/signal.h>
  11#include <asm/unistd.h>
  12#include "frame_kern.h"
  13#include "kern_util.h"
  14
  15EXPORT_SYMBOL(block_signals);
  16EXPORT_SYMBOL(unblock_signals);
  17
  18/*
  19 * OK, we're invoking a handler
  20 */
  21static void handle_signal(struct pt_regs *regs, unsigned long signr,
  22                         struct k_sigaction *ka, siginfo_t *info)
  23{
  24        sigset_t *oldset = sigmask_to_save();
  25        unsigned long sp;
  26        int err;
  27
  28        /* Did we come from a system call? */
  29        if (PT_REGS_SYSCALL_NR(regs) >= 0) {
  30                /* If so, check system call restarting.. */
  31                switch (PT_REGS_SYSCALL_RET(regs)) {
  32                case -ERESTART_RESTARTBLOCK:
  33                case -ERESTARTNOHAND:
  34                        PT_REGS_SYSCALL_RET(regs) = -EINTR;
  35                        break;
  36
  37                case -ERESTARTSYS:
  38                        if (!(ka->sa.sa_flags & SA_RESTART)) {
  39                                PT_REGS_SYSCALL_RET(regs) = -EINTR;
  40                                break;
  41                        }
  42                /* fallthrough */
  43                case -ERESTARTNOINTR:
  44                        PT_REGS_RESTART_SYSCALL(regs);
  45                        PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
  46                        break;
  47                }
  48        }
  49
  50        sp = PT_REGS_SP(regs);
  51        if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
  52                sp = current->sas_ss_sp + current->sas_ss_size;
  53
  54#ifdef CONFIG_ARCH_HAS_SC_SIGNALS
  55        if (!(ka->sa.sa_flags & SA_SIGINFO))
  56                err = setup_signal_stack_sc(sp, signr, ka, regs, oldset);
  57        else
  58#endif
  59                err = setup_signal_stack_si(sp, signr, ka, regs, info, oldset);
  60
  61        if (err)
  62                force_sigsegv(signr, current);
  63        else
  64                signal_delivered(signr, info, ka, regs, 0);
  65}
  66
  67static int kern_do_signal(struct pt_regs *regs)
  68{
  69        struct k_sigaction ka_copy;
  70        siginfo_t info;
  71        int sig, handled_sig = 0;
  72
  73        while ((sig = get_signal_to_deliver(&info, &ka_copy, regs, NULL)) > 0) {
  74                handled_sig = 1;
  75                /* Whee!  Actually deliver the signal.  */
  76                handle_signal(regs, sig, &ka_copy, &info);
  77        }
  78
  79        /* Did we come from a system call? */
  80        if (!handled_sig && (PT_REGS_SYSCALL_NR(regs) >= 0)) {
  81                /* Restart the system call - no handlers present */
  82                switch (PT_REGS_SYSCALL_RET(regs)) {
  83                case -ERESTARTNOHAND:
  84                case -ERESTARTSYS:
  85                case -ERESTARTNOINTR:
  86                        PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
  87                        PT_REGS_RESTART_SYSCALL(regs);
  88                        break;
  89                case -ERESTART_RESTARTBLOCK:
  90                        PT_REGS_ORIG_SYSCALL(regs) = __NR_restart_syscall;
  91                        PT_REGS_RESTART_SYSCALL(regs);
  92                        break;
  93                }
  94        }
  95
  96        /*
  97         * This closes a way to execute a system call on the host.  If
  98         * you set a breakpoint on a system call instruction and singlestep
  99         * from it, the tracing thread used to PTRACE_SINGLESTEP the process
 100         * rather than PTRACE_SYSCALL it, allowing the system call to execute
 101         * on the host.  The tracing thread will check this flag and
 102         * PTRACE_SYSCALL if necessary.
 103         */
 104        if (current->ptrace & PT_DTRACE)
 105                current->thread.singlestep_syscall =
 106                        is_syscall(PT_REGS_IP(&current->thread.regs));
 107
 108        /*
 109         * if there's no signal to deliver, we just put the saved sigmask
 110         * back
 111         */
 112        if (!handled_sig)
 113                restore_saved_sigmask();
 114        return handled_sig;
 115}
 116
 117int do_signal(void)
 118{
 119        return kern_do_signal(&current->thread.regs);
 120}
 121
 122/*
 123 * Atomically swap in the new signal mask, and wait for a signal.
 124 */
 125long sys_sigsuspend(int history0, int history1, old_sigset_t mask)
 126{
 127        sigset_t blocked;
 128        siginitset(&blocked, mask);
 129        return sigsuspend(&blocked);
 130}
 131
 132long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
 133{
 134        return do_sigaltstack(uss, uoss, PT_REGS_SP(&current->thread.regs));
 135}
 136