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Jeff Dike1d3468a2006-07-10 04:45:13 -07001/*
Jeff Dikeba180fd2007-10-16 01:27:00 -07002 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 * Licensed under the GPL
4 */
5
Jeff Dikec5d4bb12008-02-04 22:31:14 -08006#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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include "frame_kern.h"
Jeff Dikeba180fd2007-10-16 01:27:00 -070013#include "kern_util.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070014
15EXPORT_SYMBOL(block_signals);
16EXPORT_SYMBOL(unblock_signals);
17
Linus Torvalds1da177e2005-04-16 15:20:36 -070018/*
19 * OK, we're invoking a handler
Jeff Dike1d3468a2006-07-10 04:45:13 -070020 */
Al Viroa610d6e2012-05-21 23:42:15 -040021static void handle_signal(struct pt_regs *regs, unsigned long signr,
Al Virob7f9a112012-05-02 09:59:21 -040022 struct k_sigaction *ka, siginfo_t *info)
Linus Torvalds1da177e2005-04-16 15:20:36 -070023{
Al Virob7f9a112012-05-02 09:59:21 -040024 sigset_t *oldset = sigmask_to_save();
Linus Torvalds1da177e2005-04-16 15:20:36 -070025 unsigned long sp;
26 int err;
27
Linus Torvalds1da177e2005-04-16 15:20:36 -070028 /* Did we come from a system call? */
Jeff Dikeba180fd2007-10-16 01:27:00 -070029 if (PT_REGS_SYSCALL_NR(regs) >= 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070030 /* If so, check system call restarting.. */
Jeff Dikec5d4bb12008-02-04 22:31:14 -080031 switch (PT_REGS_SYSCALL_RET(regs)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070032 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);
Jeff Dikeba180fd2007-10-16 01:27:00 -070051 if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
Linus Torvalds1da177e2005-04-16 15:20:36 -070052 sp = current->sas_ss_sp + current->sas_ss_size;
53
54#ifdef CONFIG_ARCH_HAS_SC_SIGNALS
Jeff Dikeba180fd2007-10-16 01:27:00 -070055 if (!(ka->sa.sa_flags & SA_SIGINFO))
Linus Torvalds1da177e2005-04-16 15:20:36 -070056 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
Matt Flemingf6adb9a2012-03-23 15:01:49 -070061 if (err)
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 force_sigsegv(signr, current);
Matt Flemingd982d592012-03-23 15:01:50 -070063 else
Al Viroefee9842012-04-28 02:04:15 -040064 signal_delivered(signr, info, ka, regs, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -070065}
66
Jeff Dike2fc10622006-01-18 17:44:02 -080067static int kern_do_signal(struct pt_regs *regs)
Linus Torvalds1da177e2005-04-16 15:20:36 -070068{
69 struct k_sigaction ka_copy;
70 siginfo_t info;
71 int sig, handled_sig = 0;
72
Jeff Dikeba180fd2007-10-16 01:27:00 -070073 while ((sig = get_signal_to_deliver(&info, &ka_copy, regs, NULL)) > 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070074 handled_sig = 1;
75 /* Whee! Actually deliver the signal. */
Al Viroa610d6e2012-05-21 23:42:15 -040076 handle_signal(regs, sig, &ka_copy, &info);
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 }
78
79 /* Did we come from a system call? */
Jeff Dikeba180fd2007-10-16 01:27:00 -070080 if (!handled_sig && (PT_REGS_SYSCALL_NR(regs) >= 0)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070081 /* Restart the system call - no handlers present */
Jeff Dikec5d4bb12008-02-04 22:31:14 -080082 switch (PT_REGS_SYSCALL_RET(regs)) {
Jeff Dike2fc10622006-01-18 17:44:02 -080083 case -ERESTARTNOHAND:
84 case -ERESTARTSYS:
85 case -ERESTARTNOINTR:
Linus Torvalds1da177e2005-04-16 15:20:36 -070086 PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
87 PT_REGS_RESTART_SYSCALL(regs);
Jeff Dike2fc10622006-01-18 17:44:02 -080088 break;
89 case -ERESTART_RESTARTBLOCK:
Jeff Dike1d3468a2006-07-10 04:45:13 -070090 PT_REGS_ORIG_SYSCALL(regs) = __NR_restart_syscall;
Linus Torvalds1da177e2005-04-16 15:20:36 -070091 PT_REGS_RESTART_SYSCALL(regs);
Jeff Dike2fc10622006-01-18 17:44:02 -080092 break;
Jeff Dikeba180fd2007-10-16 01:27:00 -070093 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070094 }
95
Jeff Dikeba180fd2007-10-16 01:27:00 -070096 /*
97 * This closes a way to execute a system call on the host. If
Linus Torvalds1da177e2005-04-16 15:20:36 -070098 * 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
Jeff Dike1d3468a2006-07-10 04:45:13 -0700101 * on the host. The tracing thread will check this flag and
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 * PTRACE_SYSCALL if necessary.
103 */
Jeff Dikeba180fd2007-10-16 01:27:00 -0700104 if (current->ptrace & PT_DTRACE)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 current->thread.singlestep_syscall =
106 is_syscall(PT_REGS_IP(&current->thread.regs));
Jeff Dike2fc10622006-01-18 17:44:02 -0800107
Jeff Dikeba180fd2007-10-16 01:27:00 -0700108 /*
109 * if there's no signal to deliver, we just put the saved sigmask
110 * back
111 */
Al Viro51a7b442012-05-21 23:33:55 -0400112 if (!handled_sig)
113 restore_saved_sigmask();
Jeff Dike7c7a8942007-03-06 01:42:18 -0800114 return handled_sig;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115}
116
117int do_signal(void)
118{
Jeff Dike7c7a8942007-03-06 01:42:18 -0800119 return kern_do_signal(&current->thread.regs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120}
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{
Matt Flemingd982d592012-03-23 15:01:50 -0700127 sigset_t blocked;
Matt Flemingd982d592012-03-23 15:01:50 -0700128 siginitset(&blocked, mask);
Al Viro68f3f162012-05-21 21:42:32 -0400129 return sigsuspend(&blocked);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130}
131
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
133{
Jeff Dike7c7a8942007-03-06 01:42:18 -0800134 return do_sigaltstack(uss, uoss, PT_REGS_SP(&current->thread.regs));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135}