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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> |
8b7b80b9 | 14 | #include <linux/uprobes.h> |
18b246fa | 15 | #include <linux/key.h> |
06532a67 | 16 | #include <asm/hw_breakpoint.h> |
a3f61dc0 | 17 | #include <asm/uaccess.h> |
22e38f29 | 18 | #include <asm/unistd.h> |
ae3a197e | 19 | #include <asm/debug.h> |
22e38f29 | 20 | |
db277e9a CH |
21 | #include "signal.h" |
22 | ||
d0c3d534 OJ |
23 | /* Log an error when sending an unhandled signal to a process. Controlled |
24 | * through debug.exception-trace sysctl. | |
25 | */ | |
26 | ||
27 | int show_unhandled_signals = 0; | |
28 | ||
a3f61dc0 BH |
29 | /* |
30 | * Allocate space for the signal frame | |
31 | */ | |
32 | void __user * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, | |
efbda860 | 33 | size_t frame_size, int is_32) |
a3f61dc0 BH |
34 | { |
35 | unsigned long oldsp, newsp; | |
36 | ||
37 | /* Default to using normal stack */ | |
efbda860 | 38 | oldsp = get_clean_sp(regs, is_32); |
a3f61dc0 BH |
39 | |
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 | ||
f478f543 CH |
55 | static void check_syscall_restart(struct pt_regs *regs, struct k_sigaction *ka, |
56 | int has_handler) | |
22e38f29 BH |
57 | { |
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 | } | |
69d15f6b | 105 | |
18b246fa | 106 | static int do_signal(struct pt_regs *regs) |
f478f543 | 107 | { |
b7f9a11a | 108 | sigset_t *oldset = sigmask_to_save(); |
f478f543 CH |
109 | siginfo_t info; |
110 | int signr; | |
111 | struct k_sigaction ka; | |
112 | int ret; | |
113 | int is32 = is_32bit_task(); | |
114 | ||
f478f543 CH |
115 | signr = get_signal_to_deliver(&info, &ka, regs, NULL); |
116 | ||
f478f543 CH |
117 | /* 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 */ | |
51a7b448 | 122 | restore_saved_sigmask(); |
9a81c16b | 123 | regs->trap = 0; |
f478f543 CH |
124 | return 0; /* no signals delivered */ |
125 | } | |
126 | ||
3bffb652 | 127 | #ifndef CONFIG_PPC_ADV_DEBUG_REGS |
f478f543 CH |
128 | /* |
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 | */ | |
9422de3e MN |
133 | if (current->thread.hw_brk.address && |
134 | current->thread.hw_brk.type) | |
b9818c33 | 135 | set_breakpoint(¤t->thread.hw_brk); |
d6a61bfc | 136 | #endif |
06532a67 P |
137 | /* Re-enable the breakpoints for the signal stack */ |
138 | thread_change_pc(current, regs); | |
f478f543 CH |
139 | |
140 | if (is32) { | |
f478f543 CH |
141 | if (ka.sa.sa_flags & SA_SIGINFO) |
142 | ret = handle_rt_signal32(signr, &ka, &info, oldset, | |
a3f61dc0 | 143 | regs); |
f478f543 CH |
144 | else |
145 | ret = handle_signal32(signr, &ka, &info, oldset, | |
a3f61dc0 | 146 | regs); |
f478f543 CH |
147 | } else { |
148 | ret = handle_rt_signal64(signr, &ka, &info, oldset, regs); | |
f478f543 CH |
149 | } |
150 | ||
9a81c16b | 151 | regs->trap = 0; |
f478f543 | 152 | if (ret) { |
efee984c | 153 | signal_delivered(signr, &info, &ka, regs, |
6558ba2b | 154 | test_thread_flag(TIF_SINGLESTEP)); |
f478f543 CH |
155 | } |
156 | ||
157 | return ret; | |
158 | } | |
159 | ||
18b246fa | 160 | void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags) |
7d6d637d | 161 | { |
f57d56dd | 162 | if (thread_info_flags & _TIF_UPROBE) |
8b7b80b9 | 163 | uprobe_notify_resume(regs); |
8b7b80b9 | 164 | |
7d6d637d | 165 | if (thread_info_flags & _TIF_SIGPENDING) |
18b246fa | 166 | do_signal(regs); |
7d6d637d RM |
167 | |
168 | if (thread_info_flags & _TIF_NOTIFY_RESUME) { | |
169 | clear_thread_flag(TIF_NOTIFY_RESUME); | |
170 | tracehook_notify_resume(regs); | |
171 | } | |
172 | } |