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Benjamin Herrenschmidt22e38f22007-06-04 15:15:49 +10001/*
2 * Common signal handling code for both 32 and 64 bits
3 *
4 * Copyright (c) 2007 Benjamin Herrenschmidt, IBM Coproration
5 * Extracted from signal_32.c and signal_64.c
6 *
7 * This file is subject to the terms and conditions of the GNU General
8 * Public License. See the file README.legal in the main directory of
9 * this archive for more details.
10 */
11
Roland McGrath6558ba22008-07-27 16:49:50 +100012#include <linux/tracehook.h>
Benjamin Herrenschmidt22e38f22007-06-04 15:15:49 +100013#include <linux/signal.h>
Ananth N Mavinakayanahalli8b7b80b2012-08-23 21:31:32 +000014#include <linux/uprobes.h>
Benjamin Herrenschmidt18b246f2012-02-22 16:48:32 +110015#include <linux/key.h>
K.Prasad06532a62010-06-15 11:35:41 +053016#include <asm/hw_breakpoint.h>
Benjamin Herrenschmidta3f61dc2007-06-04 17:22:48 +100017#include <asm/uaccess.h>
Benjamin Herrenschmidt22e38f22007-06-04 15:15:49 +100018#include <asm/unistd.h>
David Howellsae3a1972012-03-28 18:30:02 +010019#include <asm/debug.h>
Benjamin Herrenschmidt22e38f22007-06-04 15:15:49 +100020
Christoph Hellwigdb277e92007-06-04 15:15:51 +100021#include "signal.h"
22
Olof Johanssond0c3d532007-10-12 10:20:07 +100023/* Log an error when sending an unhandled signal to a process. Controlled
24 * through debug.exception-trace sysctl.
25 */
26
27int show_unhandled_signals = 0;
28
Benjamin Herrenschmidta3f61dc2007-06-04 17:22:48 +100029/*
30 * Allocate space for the signal frame
31 */
32void __user * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
Josh Boyerefbda862009-03-25 06:23:59 +000033 size_t frame_size, int is_32)
Benjamin Herrenschmidta3f61dc2007-06-04 17:22:48 +100034{
35 unsigned long oldsp, newsp;
36
37 /* Default to using normal stack */
Josh Boyerefbda862009-03-25 06:23:59 +000038 oldsp = get_clean_sp(regs, is_32);
Benjamin Herrenschmidta3f61dc2007-06-04 17:22:48 +100039
40 /* Check for alt stack */
41 if ((ka->sa.sa_flags & SA_ONSTACK) &&
42 current->sas_ss_size && !on_sig_stack(oldsp))
43 oldsp = (current->sas_ss_sp + current->sas_ss_size);
44
45 /* Get aligned frame */
46 newsp = (oldsp - frame_size) & ~0xFUL;
47
48 /* Check access */
49 if (!access_ok(VERIFY_WRITE, (void __user *)newsp, oldsp - newsp))
50 return NULL;
51
52 return (void __user *)newsp;
53}
54
Christoph Hellwigf478f542007-06-04 15:15:52 +100055static void check_syscall_restart(struct pt_regs *regs, struct k_sigaction *ka,
56 int has_handler)
Benjamin Herrenschmidt22e38f22007-06-04 15:15:49 +100057{
58 unsigned long ret = regs->gpr[3];
59 int restart = 1;
60
61 /* syscall ? */
62 if (TRAP(regs) != 0x0C00)
63 return;
64
65 /* error signalled ? */
66 if (!(regs->ccr & 0x10000000))
67 return;
68
69 switch (ret) {
70 case ERESTART_RESTARTBLOCK:
71 case ERESTARTNOHAND:
72 /* ERESTARTNOHAND means that the syscall should only be
73 * restarted if there was no handler for the signal, and since
74 * we only get here if there is a handler, we dont restart.
75 */
76 restart = !has_handler;
77 break;
78 case ERESTARTSYS:
79 /* ERESTARTSYS means to restart the syscall if there is no
80 * handler or the handler was registered with SA_RESTART
81 */
82 restart = !has_handler || (ka->sa.sa_flags & SA_RESTART) != 0;
83 break;
84 case ERESTARTNOINTR:
85 /* ERESTARTNOINTR means that the syscall should be
86 * called again after the signal handler returns.
87 */
88 break;
89 default:
90 return;
91 }
92 if (restart) {
93 if (ret == ERESTART_RESTARTBLOCK)
94 regs->gpr[0] = __NR_restart_syscall;
95 else
96 regs->gpr[3] = regs->orig_gpr3;
97 regs->nip -= 4;
98 regs->result = 0;
99 } else {
100 regs->result = -EINTR;
101 regs->gpr[3] = EINTR;
102 regs->ccr |= 0x10000000;
103 }
104}
Christoph Hellwig69d15f62007-06-04 15:15:50 +1000105
Benjamin Herrenschmidt18b246f2012-02-22 16:48:32 +1100106static int do_signal(struct pt_regs *regs)
Christoph Hellwigf478f542007-06-04 15:15:52 +1000107{
Al Virob7f9a112012-05-02 09:59:21 -0400108 sigset_t *oldset = sigmask_to_save();
Christoph Hellwigf478f542007-06-04 15:15:52 +1000109 siginfo_t info;
110 int signr;
111 struct k_sigaction ka;
112 int ret;
113 int is32 = is_32bit_task();
114
Christoph Hellwigf478f542007-06-04 15:15:52 +1000115 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
116
Christoph Hellwigf478f542007-06-04 15:15:52 +1000117 /* Is there any syscall restart business here ? */
118 check_syscall_restart(regs, &ka, signr > 0);
119
120 if (signr <= 0) {
121 /* No signal to deliver -- put the saved sigmask back */
Al Viro51a7b442012-05-21 23:33:55 -0400122 restore_saved_sigmask();
Al Viro9a81c162010-09-20 21:48:57 +0100123 regs->trap = 0;
Christoph Hellwigf478f542007-06-04 15:15:52 +1000124 return 0; /* no signals delivered */
125 }
126
Dave Kleikamp3bffb652010-02-08 11:51:18 +0000127#ifndef CONFIG_PPC_ADV_DEBUG_REGS
Christoph Hellwigf478f542007-06-04 15:15:52 +1000128 /*
129 * Reenable the DABR before delivering the signal to
130 * user space. The DABR will have been cleared if it
131 * triggered inside the kernel.
132 */
Dave Kleikamp3bffb652010-02-08 11:51:18 +0000133 if (current->thread.dabr)
Michael Neuling4474ef02012-09-06 21:24:56 +0000134 set_dabr(current->thread.dabr, current->thread.dabrx);
Luis Machadod6a61bf2008-07-24 02:10:41 +1000135#endif
K.Prasad06532a62010-06-15 11:35:41 +0530136 /* Re-enable the breakpoints for the signal stack */
137 thread_change_pc(current, regs);
Christoph Hellwigf478f542007-06-04 15:15:52 +1000138
139 if (is32) {
Christoph Hellwigf478f542007-06-04 15:15:52 +1000140 if (ka.sa.sa_flags & SA_SIGINFO)
141 ret = handle_rt_signal32(signr, &ka, &info, oldset,
Benjamin Herrenschmidta3f61dc2007-06-04 17:22:48 +1000142 regs);
Christoph Hellwigf478f542007-06-04 15:15:52 +1000143 else
144 ret = handle_signal32(signr, &ka, &info, oldset,
Benjamin Herrenschmidta3f61dc2007-06-04 17:22:48 +1000145 regs);
Christoph Hellwigf478f542007-06-04 15:15:52 +1000146 } else {
147 ret = handle_rt_signal64(signr, &ka, &info, oldset, regs);
Christoph Hellwigf478f542007-06-04 15:15:52 +1000148 }
149
Al Viro9a81c162010-09-20 21:48:57 +0100150 regs->trap = 0;
Christoph Hellwigf478f542007-06-04 15:15:52 +1000151 if (ret) {
Al Viroefee9842012-04-28 02:04:15 -0400152 signal_delivered(signr, &info, &ka, regs,
Roland McGrath6558ba22008-07-27 16:49:50 +1000153 test_thread_flag(TIF_SINGLESTEP));
Christoph Hellwigf478f542007-06-04 15:15:52 +1000154 }
155
156 return ret;
157}
158
Benjamin Herrenschmidt18b246f2012-02-22 16:48:32 +1100159void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)
Roland McGrath7d6d6372008-07-27 16:52:52 +1000160{
Oleg Nesterovf57d56d2012-10-28 18:17:11 +0100161 if (thread_info_flags & _TIF_UPROBE)
Ananth N Mavinakayanahalli8b7b80b2012-08-23 21:31:32 +0000162 uprobe_notify_resume(regs);
Ananth N Mavinakayanahalli8b7b80b2012-08-23 21:31:32 +0000163
Roland McGrath7d6d6372008-07-27 16:52:52 +1000164 if (thread_info_flags & _TIF_SIGPENDING)
Benjamin Herrenschmidt18b246f2012-02-22 16:48:32 +1100165 do_signal(regs);
Roland McGrath7d6d6372008-07-27 16:52:52 +1000166
167 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
168 clear_thread_flag(TIF_NOTIFY_RESUME);
169 tracehook_notify_resume(regs);
170 }
171}
172
Christoph Hellwig69d15f62007-06-04 15:15:50 +1000173long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
174 unsigned long r5, unsigned long r6, unsigned long r7,
175 unsigned long r8, struct pt_regs *regs)
176{
177 return do_sigaltstack(uss, uoss, regs->gpr[1]);
178}