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 /* Always make any pending restarted system calls return -EINTR */
33 current_thread_info()->restart_block.fn = do_no_restart_syscall;
35 /* Did we come from a system call? */
36 if (PT_REGS_SYSCALL_NR(regs) >= 0) {
37 /* If so, check system call restarting.. */
38 switch (PT_REGS_SYSCALL_RET(regs)) {
39 case -ERESTART_RESTARTBLOCK:
41 PT_REGS_SYSCALL_RET(regs) = -EINTR;
45 if (!(ka->sa.sa_flags & SA_RESTART)) {
46 PT_REGS_SYSCALL_RET(regs) = -EINTR;
51 PT_REGS_RESTART_SYSCALL(regs);
52 PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
57 sp = PT_REGS_SP(regs);
58 if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
59 sp = current->sas_ss_sp + current->sas_ss_size;
61 #ifdef CONFIG_ARCH_HAS_SC_SIGNALS
62 if (!(ka->sa.sa_flags & SA_SIGINFO))
63 err = setup_signal_stack_sc(sp, signr, ka, regs, oldset);
66 err = setup_signal_stack_si(sp, signr, ka, regs, info, oldset);
69 spin_lock_irq(¤t->sighand->siglock);
70 current->blocked = *oldset;
72 spin_unlock_irq(¤t->sighand->siglock);
73 force_sigsegv(signr, current);
75 spin_lock_irq(¤t->sighand->siglock);
76 sigorsets(¤t->blocked, ¤t->blocked,
78 if (!(ka->sa.sa_flags & SA_NODEFER))
79 sigaddset(¤t->blocked, signr);
81 spin_unlock_irq(¤t->sighand->siglock);
87 static int kern_do_signal(struct pt_regs *regs)
89 struct k_sigaction ka_copy;
92 int sig, handled_sig = 0;
94 if (test_thread_flag(TIF_RESTORE_SIGMASK))
95 oldset = ¤t->saved_sigmask;
97 oldset = ¤t->blocked;
99 while ((sig = get_signal_to_deliver(&info, &ka_copy, regs, NULL)) > 0) {
101 /* Whee! Actually deliver the signal. */
102 if (!handle_signal(regs, sig, &ka_copy, &info, oldset)) {
104 * a signal was successfully delivered; the saved
105 * sigmask will have been stored in the signal frame,
106 * and will be restored by sigreturn, so we can simply
107 * clear the TIF_RESTORE_SIGMASK flag
109 if (test_thread_flag(TIF_RESTORE_SIGMASK))
110 clear_thread_flag(TIF_RESTORE_SIGMASK);
115 /* Did we come from a system call? */
116 if (!handled_sig && (PT_REGS_SYSCALL_NR(regs) >= 0)) {
117 /* Restart the system call - no handlers present */
118 switch (PT_REGS_SYSCALL_RET(regs)) {
119 case -ERESTARTNOHAND:
121 case -ERESTARTNOINTR:
122 PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
123 PT_REGS_RESTART_SYSCALL(regs);
125 case -ERESTART_RESTARTBLOCK:
126 PT_REGS_ORIG_SYSCALL(regs) = __NR_restart_syscall;
127 PT_REGS_RESTART_SYSCALL(regs);
133 * This closes a way to execute a system call on the host. If
134 * you set a breakpoint on a system call instruction and singlestep
135 * from it, the tracing thread used to PTRACE_SINGLESTEP the process
136 * rather than PTRACE_SYSCALL it, allowing the system call to execute
137 * on the host. The tracing thread will check this flag and
138 * PTRACE_SYSCALL if necessary.
140 if (current->ptrace & PT_DTRACE)
141 current->thread.singlestep_syscall =
142 is_syscall(PT_REGS_IP(¤t->thread.regs));
145 * if there's no signal to deliver, we just put the saved sigmask
148 if (!handled_sig && test_thread_flag(TIF_RESTORE_SIGMASK)) {
149 clear_thread_flag(TIF_RESTORE_SIGMASK);
150 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
157 return kern_do_signal(¤t->thread.regs);
161 * Atomically swap in the new signal mask, and wait for a signal.
163 long sys_sigsuspend(int history0, int history1, old_sigset_t mask)
166 spin_lock_irq(¤t->sighand->siglock);
167 current->saved_sigmask = current->blocked;
168 siginitset(¤t->blocked, mask);
170 spin_unlock_irq(¤t->sighand->siglock);
172 current->state = TASK_INTERRUPTIBLE;
174 set_thread_flag(TIF_RESTORE_SIGMASK);
175 return -ERESTARTNOHAND;
178 long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
180 return do_sigaltstack(uss, uoss, PT_REGS_SP(¤t->thread.regs));