Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
[deliverable/linux.git] / arch / powerpc / kernel / signal.c
1 /*
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
12 #include <linux/ptrace.h>
13 #include <linux/signal.h>
14 #include <asm/uaccess.h>
15 #include <asm/unistd.h>
16
17 #include "signal.h"
18
19 /*
20 * Allocate space for the signal frame
21 */
22 void __user * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
23 size_t frame_size)
24 {
25 unsigned long oldsp, newsp;
26
27 /* Default to using normal stack */
28 oldsp = regs->gpr[1];
29
30 /* Check for alt stack */
31 if ((ka->sa.sa_flags & SA_ONSTACK) &&
32 current->sas_ss_size && !on_sig_stack(oldsp))
33 oldsp = (current->sas_ss_sp + current->sas_ss_size);
34
35 /* Get aligned frame */
36 newsp = (oldsp - frame_size) & ~0xFUL;
37
38 /* Check access */
39 if (!access_ok(VERIFY_WRITE, (void __user *)newsp, oldsp - newsp))
40 return NULL;
41
42 return (void __user *)newsp;
43 }
44
45
46 /*
47 * Restore the user process's signal mask
48 */
49 void restore_sigmask(sigset_t *set)
50 {
51 sigdelsetmask(set, ~_BLOCKABLE);
52 spin_lock_irq(&current->sighand->siglock);
53 current->blocked = *set;
54 recalc_sigpending();
55 spin_unlock_irq(&current->sighand->siglock);
56 }
57
58 static void check_syscall_restart(struct pt_regs *regs, struct k_sigaction *ka,
59 int has_handler)
60 {
61 unsigned long ret = regs->gpr[3];
62 int restart = 1;
63
64 /* syscall ? */
65 if (TRAP(regs) != 0x0C00)
66 return;
67
68 /* error signalled ? */
69 if (!(regs->ccr & 0x10000000))
70 return;
71
72 switch (ret) {
73 case ERESTART_RESTARTBLOCK:
74 case ERESTARTNOHAND:
75 /* ERESTARTNOHAND means that the syscall should only be
76 * restarted if there was no handler for the signal, and since
77 * we only get here if there is a handler, we dont restart.
78 */
79 restart = !has_handler;
80 break;
81 case ERESTARTSYS:
82 /* ERESTARTSYS means to restart the syscall if there is no
83 * handler or the handler was registered with SA_RESTART
84 */
85 restart = !has_handler || (ka->sa.sa_flags & SA_RESTART) != 0;
86 break;
87 case ERESTARTNOINTR:
88 /* ERESTARTNOINTR means that the syscall should be
89 * called again after the signal handler returns.
90 */
91 break;
92 default:
93 return;
94 }
95 if (restart) {
96 if (ret == ERESTART_RESTARTBLOCK)
97 regs->gpr[0] = __NR_restart_syscall;
98 else
99 regs->gpr[3] = regs->orig_gpr3;
100 regs->nip -= 4;
101 regs->result = 0;
102 } else {
103 regs->result = -EINTR;
104 regs->gpr[3] = EINTR;
105 regs->ccr |= 0x10000000;
106 }
107 }
108
109 int do_signal(sigset_t *oldset, struct pt_regs *regs)
110 {
111 siginfo_t info;
112 int signr;
113 struct k_sigaction ka;
114 int ret;
115 int is32 = is_32bit_task();
116
117 if (test_thread_flag(TIF_RESTORE_SIGMASK))
118 oldset = &current->saved_sigmask;
119 else if (!oldset)
120 oldset = &current->blocked;
121
122 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
123
124 /* Is there any syscall restart business here ? */
125 check_syscall_restart(regs, &ka, signr > 0);
126
127 if (signr <= 0) {
128 /* No signal to deliver -- put the saved sigmask back */
129 if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
130 clear_thread_flag(TIF_RESTORE_SIGMASK);
131 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
132 }
133 return 0; /* no signals delivered */
134 }
135
136 /*
137 * Reenable the DABR before delivering the signal to
138 * user space. The DABR will have been cleared if it
139 * triggered inside the kernel.
140 */
141 if (current->thread.dabr)
142 set_dabr(current->thread.dabr);
143
144 if (is32) {
145 if (ka.sa.sa_flags & SA_SIGINFO)
146 ret = handle_rt_signal32(signr, &ka, &info, oldset,
147 regs);
148 else
149 ret = handle_signal32(signr, &ka, &info, oldset,
150 regs);
151 } else {
152 ret = handle_rt_signal64(signr, &ka, &info, oldset, regs);
153 }
154
155 if (ret) {
156 spin_lock_irq(&current->sighand->siglock);
157 sigorsets(&current->blocked, &current->blocked,
158 &ka.sa.sa_mask);
159 if (!(ka.sa.sa_flags & SA_NODEFER))
160 sigaddset(&current->blocked, signr);
161 recalc_sigpending();
162 spin_unlock_irq(&current->sighand->siglock);
163
164 /*
165 * A signal was successfully delivered; the saved sigmask is in
166 * its frame, and we can clear the TIF_RESTORE_SIGMASK flag.
167 */
168 if (test_thread_flag(TIF_RESTORE_SIGMASK))
169 clear_thread_flag(TIF_RESTORE_SIGMASK);
170 }
171
172 return ret;
173 }
174
175 long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
176 unsigned long r5, unsigned long r6, unsigned long r7,
177 unsigned long r8, struct pt_regs *regs)
178 {
179 return do_sigaltstack(uss, uoss, regs->gpr[1]);
180 }
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