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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> |
18b246fa | 14 | #include <linux/key.h> |
06532a67 | 15 | #include <asm/hw_breakpoint.h> |
a3f61dc0 | 16 | #include <asm/uaccess.h> |
22e38f29 BH |
17 | #include <asm/unistd.h> |
18 | ||
db277e9a CH |
19 | #include "signal.h" |
20 | ||
d0c3d534 OJ |
21 | /* Log an error when sending an unhandled signal to a process. Controlled |
22 | * through debug.exception-trace sysctl. | |
23 | */ | |
24 | ||
25 | int show_unhandled_signals = 0; | |
26 | ||
a3f61dc0 BH |
27 | /* |
28 | * Allocate space for the signal frame | |
29 | */ | |
30 | void __user * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, | |
efbda860 | 31 | size_t frame_size, int is_32) |
a3f61dc0 BH |
32 | { |
33 | unsigned long oldsp, newsp; | |
34 | ||
35 | /* Default to using normal stack */ | |
efbda860 | 36 | oldsp = get_clean_sp(regs, is_32); |
a3f61dc0 BH |
37 | |
38 | /* Check for alt stack */ | |
39 | if ((ka->sa.sa_flags & SA_ONSTACK) && | |
40 | current->sas_ss_size && !on_sig_stack(oldsp)) | |
41 | oldsp = (current->sas_ss_sp + current->sas_ss_size); | |
42 | ||
43 | /* Get aligned frame */ | |
44 | newsp = (oldsp - frame_size) & ~0xFUL; | |
45 | ||
46 | /* Check access */ | |
47 | if (!access_ok(VERIFY_WRITE, (void __user *)newsp, oldsp - newsp)) | |
48 | return NULL; | |
49 | ||
50 | return (void __user *)newsp; | |
51 | } | |
52 | ||
f478f543 | 53 | |
db277e9a CH |
54 | /* |
55 | * Restore the user process's signal mask | |
56 | */ | |
57 | void restore_sigmask(sigset_t *set) | |
58 | { | |
59 | sigdelsetmask(set, ~_BLOCKABLE); | |
a2007ce8 | 60 | set_current_blocked(set); |
db277e9a CH |
61 | } |
62 | ||
f478f543 CH |
63 | static void check_syscall_restart(struct pt_regs *regs, struct k_sigaction *ka, |
64 | int has_handler) | |
22e38f29 BH |
65 | { |
66 | unsigned long ret = regs->gpr[3]; | |
67 | int restart = 1; | |
68 | ||
69 | /* syscall ? */ | |
70 | if (TRAP(regs) != 0x0C00) | |
71 | return; | |
72 | ||
73 | /* error signalled ? */ | |
74 | if (!(regs->ccr & 0x10000000)) | |
75 | return; | |
76 | ||
77 | switch (ret) { | |
78 | case ERESTART_RESTARTBLOCK: | |
79 | case ERESTARTNOHAND: | |
80 | /* ERESTARTNOHAND means that the syscall should only be | |
81 | * restarted if there was no handler for the signal, and since | |
82 | * we only get here if there is a handler, we dont restart. | |
83 | */ | |
84 | restart = !has_handler; | |
85 | break; | |
86 | case ERESTARTSYS: | |
87 | /* ERESTARTSYS means to restart the syscall if there is no | |
88 | * handler or the handler was registered with SA_RESTART | |
89 | */ | |
90 | restart = !has_handler || (ka->sa.sa_flags & SA_RESTART) != 0; | |
91 | break; | |
92 | case ERESTARTNOINTR: | |
93 | /* ERESTARTNOINTR means that the syscall should be | |
94 | * called again after the signal handler returns. | |
95 | */ | |
96 | break; | |
97 | default: | |
98 | return; | |
99 | } | |
100 | if (restart) { | |
101 | if (ret == ERESTART_RESTARTBLOCK) | |
102 | regs->gpr[0] = __NR_restart_syscall; | |
103 | else | |
104 | regs->gpr[3] = regs->orig_gpr3; | |
105 | regs->nip -= 4; | |
106 | regs->result = 0; | |
107 | } else { | |
108 | regs->result = -EINTR; | |
109 | regs->gpr[3] = EINTR; | |
110 | regs->ccr |= 0x10000000; | |
111 | } | |
112 | } | |
69d15f6b | 113 | |
18b246fa | 114 | static int do_signal(struct pt_regs *regs) |
f478f543 | 115 | { |
18b246fa | 116 | sigset_t *oldset; |
f478f543 CH |
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 | 124 | oldset = ¤t->saved_sigmask; |
18b246fa | 125 | else |
f478f543 CH |
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 | } | |
9a81c16b | 140 | regs->trap = 0; |
f478f543 CH |
141 | return 0; /* no signals delivered */ |
142 | } | |
143 | ||
3bffb652 | 144 | #ifndef CONFIG_PPC_ADV_DEBUG_REGS |
f478f543 CH |
145 | /* |
146 | * Reenable the DABR before delivering the signal to | |
147 | * user space. The DABR will have been cleared if it | |
148 | * triggered inside the kernel. | |
149 | */ | |
3bffb652 | 150 | if (current->thread.dabr) |
f478f543 | 151 | set_dabr(current->thread.dabr); |
d6a61bfc | 152 | #endif |
06532a67 P |
153 | /* Re-enable the breakpoints for the signal stack */ |
154 | thread_change_pc(current, regs); | |
f478f543 CH |
155 | |
156 | if (is32) { | |
f478f543 CH |
157 | if (ka.sa.sa_flags & SA_SIGINFO) |
158 | ret = handle_rt_signal32(signr, &ka, &info, oldset, | |
a3f61dc0 | 159 | regs); |
f478f543 CH |
160 | else |
161 | ret = handle_signal32(signr, &ka, &info, oldset, | |
a3f61dc0 | 162 | regs); |
f478f543 CH |
163 | } else { |
164 | ret = handle_rt_signal64(signr, &ka, &info, oldset, regs); | |
f478f543 CH |
165 | } |
166 | ||
9a81c16b | 167 | regs->trap = 0; |
f478f543 | 168 | if (ret) { |
a2007ce8 | 169 | block_sigmask(&ka, signr); |
f478f543 CH |
170 | |
171 | /* | |
172 | * A signal was successfully delivered; the saved sigmask is in | |
7a10174e | 173 | * its frame, and we can clear the TLF_RESTORE_SIGMASK flag. |
f478f543 | 174 | */ |
7a10174e | 175 | current_thread_info()->local_flags &= ~_TLF_RESTORE_SIGMASK; |
6558ba2b RM |
176 | |
177 | /* | |
178 | * Let tracing know that we've done the handler setup. | |
179 | */ | |
180 | tracehook_signal_handler(signr, &info, &ka, regs, | |
181 | test_thread_flag(TIF_SINGLESTEP)); | |
f478f543 CH |
182 | } |
183 | ||
184 | return ret; | |
185 | } | |
186 | ||
18b246fa | 187 | void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags) |
7d6d637d RM |
188 | { |
189 | if (thread_info_flags & _TIF_SIGPENDING) | |
18b246fa | 190 | do_signal(regs); |
7d6d637d RM |
191 | |
192 | if (thread_info_flags & _TIF_NOTIFY_RESUME) { | |
193 | clear_thread_flag(TIF_NOTIFY_RESUME); | |
194 | tracehook_notify_resume(regs); | |
18b246fa BH |
195 | if (current->replacement_session_keyring) |
196 | key_replace_session_keyring(); | |
7d6d637d RM |
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 | } |