2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Licensed under the GPL
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"
15 EXPORT_SYMBOL(block_signals);
16 EXPORT_SYMBOL(unblock_signals);
18 #define _S(nr) (1<<((nr)-1))
20 #define _BLOCKABLE (~(_S(SIGKILL) | _S(SIGSTOP)))
23 * OK, we're invoking a handler
25 static int handle_signal(struct pt_regs *regs, unsigned long signr,
26 struct k_sigaction *ka, siginfo_t *info,
32 /* Did we come from a system call? */
33 if (PT_REGS_SYSCALL_NR(regs) >= 0) {
34 /* If so, check system call restarting.. */
35 switch (PT_REGS_SYSCALL_RET(regs)) {
36 case -ERESTART_RESTARTBLOCK:
38 PT_REGS_SYSCALL_RET(regs) = -EINTR;
42 if (!(ka->sa.sa_flags & SA_RESTART)) {
43 PT_REGS_SYSCALL_RET(regs) = -EINTR;
48 PT_REGS_RESTART_SYSCALL(regs);
49 PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
54 sp = PT_REGS_SP(regs);
55 if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
56 sp = current->sas_ss_sp + current->sas_ss_size;
58 #ifdef CONFIG_ARCH_HAS_SC_SIGNALS
59 if (!(ka->sa.sa_flags & SA_SIGINFO))
60 err = setup_signal_stack_sc(sp, signr, ka, regs, oldset);
63 err = setup_signal_stack_si(sp, signr, ka, regs, info, oldset);
66 force_sigsegv(signr, current);
68 block_sigmask(ka, signr);
73 static int kern_do_signal(struct pt_regs *regs)
75 struct k_sigaction ka_copy;
77 int sig, handled_sig = 0;
79 while ((sig = get_signal_to_deliver(&info, &ka_copy, regs, NULL)) > 0) {
81 if (test_thread_flag(TIF_RESTORE_SIGMASK))
82 oldset = ¤t->saved_sigmask;
84 oldset = ¤t->blocked;
86 /* Whee! Actually deliver the signal. */
87 if (!handle_signal(regs, sig, &ka_copy, &info, oldset)) {
89 * a signal was successfully delivered; the saved
90 * sigmask will have been stored in the signal frame,
91 * and will be restored by sigreturn, so we can simply
92 * clear the TIF_RESTORE_SIGMASK flag
94 if (test_thread_flag(TIF_RESTORE_SIGMASK))
95 clear_thread_flag(TIF_RESTORE_SIGMASK);
100 /* Did we come from a system call? */
101 if (!handled_sig && (PT_REGS_SYSCALL_NR(regs) >= 0)) {
102 /* Restart the system call - no handlers present */
103 switch (PT_REGS_SYSCALL_RET(regs)) {
104 case -ERESTARTNOHAND:
106 case -ERESTARTNOINTR:
107 PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
108 PT_REGS_RESTART_SYSCALL(regs);
110 case -ERESTART_RESTARTBLOCK:
111 PT_REGS_ORIG_SYSCALL(regs) = __NR_restart_syscall;
112 PT_REGS_RESTART_SYSCALL(regs);
118 * This closes a way to execute a system call on the host. If
119 * you set a breakpoint on a system call instruction and singlestep
120 * from it, the tracing thread used to PTRACE_SINGLESTEP the process
121 * rather than PTRACE_SYSCALL it, allowing the system call to execute
122 * on the host. The tracing thread will check this flag and
123 * PTRACE_SYSCALL if necessary.
125 if (current->ptrace & PT_DTRACE)
126 current->thread.singlestep_syscall =
127 is_syscall(PT_REGS_IP(¤t->thread.regs));
130 * if there's no signal to deliver, we just put the saved sigmask
133 if (!handled_sig && test_thread_flag(TIF_RESTORE_SIGMASK)) {
134 clear_thread_flag(TIF_RESTORE_SIGMASK);
135 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
142 return kern_do_signal(¤t->thread.regs);
146 * Atomically swap in the new signal mask, and wait for a signal.
148 long sys_sigsuspend(int history0, int history1, old_sigset_t mask)
151 siginitset(&blocked, mask);
152 return sigsuspend(&blocked);
155 long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
157 return do_sigaltstack(uss, uoss, PT_REGS_SP(¤t->thread.regs));