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22e38f29 BH |
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 | ||
6558ba2b | 12 | #include <linux/tracehook.h> |
22e38f29 | 13 | #include <linux/signal.h> |
a3f61dc0 | 14 | #include <asm/uaccess.h> |
22e38f29 BH |
15 | #include <asm/unistd.h> |
16 | ||
db277e9a CH |
17 | #include "signal.h" |
18 | ||
d0c3d534 OJ |
19 | /* Log an error when sending an unhandled signal to a process. Controlled |
20 | * through debug.exception-trace sysctl. | |
21 | */ | |
22 | ||
23 | int show_unhandled_signals = 0; | |
24 | ||
a3f61dc0 BH |
25 | /* |
26 | * Allocate space for the signal frame | |
27 | */ | |
28 | void __user * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, | |
efbda860 | 29 | size_t frame_size, int is_32) |
a3f61dc0 BH |
30 | { |
31 | unsigned long oldsp, newsp; | |
32 | ||
33 | /* Default to using normal stack */ | |
efbda860 | 34 | oldsp = get_clean_sp(regs, is_32); |
a3f61dc0 BH |
35 | |
36 | /* Check for alt stack */ | |
37 | if ((ka->sa.sa_flags & SA_ONSTACK) && | |
38 | current->sas_ss_size && !on_sig_stack(oldsp)) | |
39 | oldsp = (current->sas_ss_sp + current->sas_ss_size); | |
40 | ||
41 | /* Get aligned frame */ | |
42 | newsp = (oldsp - frame_size) & ~0xFUL; | |
43 | ||
44 | /* Check access */ | |
45 | if (!access_ok(VERIFY_WRITE, (void __user *)newsp, oldsp - newsp)) | |
46 | return NULL; | |
47 | ||
48 | return (void __user *)newsp; | |
49 | } | |
50 | ||
f478f543 | 51 | |
db277e9a CH |
52 | /* |
53 | * Restore the user process's signal mask | |
54 | */ | |
55 | void restore_sigmask(sigset_t *set) | |
56 | { | |
57 | sigdelsetmask(set, ~_BLOCKABLE); | |
58 | spin_lock_irq(¤t->sighand->siglock); | |
59 | current->blocked = *set; | |
60 | recalc_sigpending(); | |
61 | spin_unlock_irq(¤t->sighand->siglock); | |
62 | } | |
63 | ||
f478f543 CH |
64 | static void check_syscall_restart(struct pt_regs *regs, struct k_sigaction *ka, |
65 | int has_handler) | |
22e38f29 BH |
66 | { |
67 | unsigned long ret = regs->gpr[3]; | |
68 | int restart = 1; | |
69 | ||
70 | /* syscall ? */ | |
71 | if (TRAP(regs) != 0x0C00) | |
72 | return; | |
73 | ||
74 | /* error signalled ? */ | |
75 | if (!(regs->ccr & 0x10000000)) | |
76 | return; | |
77 | ||
78 | switch (ret) { | |
79 | case ERESTART_RESTARTBLOCK: | |
80 | case ERESTARTNOHAND: | |
81 | /* ERESTARTNOHAND means that the syscall should only be | |
82 | * restarted if there was no handler for the signal, and since | |
83 | * we only get here if there is a handler, we dont restart. | |
84 | */ | |
85 | restart = !has_handler; | |
86 | break; | |
87 | case ERESTARTSYS: | |
88 | /* ERESTARTSYS means to restart the syscall if there is no | |
89 | * handler or the handler was registered with SA_RESTART | |
90 | */ | |
91 | restart = !has_handler || (ka->sa.sa_flags & SA_RESTART) != 0; | |
92 | break; | |
93 | case ERESTARTNOINTR: | |
94 | /* ERESTARTNOINTR means that the syscall should be | |
95 | * called again after the signal handler returns. | |
96 | */ | |
97 | break; | |
98 | default: | |
99 | return; | |
100 | } | |
101 | if (restart) { | |
102 | if (ret == ERESTART_RESTARTBLOCK) | |
103 | regs->gpr[0] = __NR_restart_syscall; | |
104 | else | |
105 | regs->gpr[3] = regs->orig_gpr3; | |
106 | regs->nip -= 4; | |
107 | regs->result = 0; | |
108 | } else { | |
109 | regs->result = -EINTR; | |
110 | regs->gpr[3] = EINTR; | |
111 | regs->ccr |= 0x10000000; | |
112 | } | |
113 | } | |
69d15f6b | 114 | |
7d6d637d | 115 | static int do_signal_pending(sigset_t *oldset, struct pt_regs *regs) |
f478f543 CH |
116 | { |
117 | siginfo_t info; | |
118 | int signr; | |
119 | struct k_sigaction ka; | |
120 | int ret; | |
121 | int is32 = is_32bit_task(); | |
122 | ||
7a10174e | 123 | if (current_thread_info()->local_flags & _TLF_RESTORE_SIGMASK) |
f478f543 CH |
124 | oldset = ¤t->saved_sigmask; |
125 | else if (!oldset) | |
126 | oldset = ¤t->blocked; | |
127 | ||
128 | signr = get_signal_to_deliver(&info, &ka, regs, NULL); | |
129 | ||
f478f543 CH |
130 | /* Is there any syscall restart business here ? */ |
131 | check_syscall_restart(regs, &ka, signr > 0); | |
132 | ||
133 | if (signr <= 0) { | |
7a10174e | 134 | struct thread_info *ti = current_thread_info(); |
f478f543 | 135 | /* No signal to deliver -- put the saved sigmask back */ |
7a10174e RM |
136 | if (ti->local_flags & _TLF_RESTORE_SIGMASK) { |
137 | ti->local_flags &= ~_TLF_RESTORE_SIGMASK; | |
f478f543 CH |
138 | sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); |
139 | } | |
140 | return 0; /* no signals delivered */ | |
141 | } | |
142 | ||
3bffb652 | 143 | #ifndef CONFIG_PPC_ADV_DEBUG_REGS |
f478f543 CH |
144 | /* |
145 | * Reenable the DABR before delivering the signal to | |
146 | * user space. The DABR will have been cleared if it | |
147 | * triggered inside the kernel. | |
148 | */ | |
3bffb652 | 149 | if (current->thread.dabr) |
f478f543 | 150 | set_dabr(current->thread.dabr); |
d6a61bfc | 151 | #endif |
f478f543 CH |
152 | |
153 | if (is32) { | |
f478f543 CH |
154 | if (ka.sa.sa_flags & SA_SIGINFO) |
155 | ret = handle_rt_signal32(signr, &ka, &info, oldset, | |
a3f61dc0 | 156 | regs); |
f478f543 CH |
157 | else |
158 | ret = handle_signal32(signr, &ka, &info, oldset, | |
a3f61dc0 | 159 | regs); |
f478f543 CH |
160 | } else { |
161 | ret = handle_rt_signal64(signr, &ka, &info, oldset, regs); | |
f478f543 CH |
162 | } |
163 | ||
164 | if (ret) { | |
165 | spin_lock_irq(¤t->sighand->siglock); | |
166 | sigorsets(¤t->blocked, ¤t->blocked, | |
167 | &ka.sa.sa_mask); | |
168 | if (!(ka.sa.sa_flags & SA_NODEFER)) | |
169 | sigaddset(¤t->blocked, signr); | |
170 | recalc_sigpending(); | |
171 | spin_unlock_irq(¤t->sighand->siglock); | |
172 | ||
173 | /* | |
174 | * A signal was successfully delivered; the saved sigmask is in | |
7a10174e | 175 | * its frame, and we can clear the TLF_RESTORE_SIGMASK flag. |
f478f543 | 176 | */ |
7a10174e | 177 | current_thread_info()->local_flags &= ~_TLF_RESTORE_SIGMASK; |
6558ba2b RM |
178 | |
179 | /* | |
180 | * Let tracing know that we've done the handler setup. | |
181 | */ | |
182 | tracehook_signal_handler(signr, &info, &ka, regs, | |
183 | test_thread_flag(TIF_SINGLESTEP)); | |
f478f543 CH |
184 | } |
185 | ||
186 | return ret; | |
187 | } | |
188 | ||
7d6d637d RM |
189 | void do_signal(struct pt_regs *regs, unsigned long thread_info_flags) |
190 | { | |
191 | if (thread_info_flags & _TIF_SIGPENDING) | |
192 | do_signal_pending(NULL, regs); | |
193 | ||
194 | if (thread_info_flags & _TIF_NOTIFY_RESUME) { | |
195 | clear_thread_flag(TIF_NOTIFY_RESUME); | |
196 | tracehook_notify_resume(regs); | |
197 | } | |
198 | } | |
199 | ||
69d15f6b CH |
200 | long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, |
201 | unsigned long r5, unsigned long r6, unsigned long r7, | |
202 | unsigned long r8, struct pt_regs *regs) | |
203 | { | |
204 | return do_sigaltstack(uss, uoss, regs->gpr[1]); | |
205 | } |