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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> |
106ed886 | 16 | #include <linux/context_tracking.h> |
06532a67 | 17 | #include <asm/hw_breakpoint.h> |
a3f61dc0 | 18 | #include <asm/uaccess.h> |
22e38f29 | 19 | #include <asm/unistd.h> |
ae3a197e | 20 | #include <asm/debug.h> |
2b3f8e87 | 21 | #include <asm/tm.h> |
22e38f29 | 22 | |
db277e9a CH |
23 | #include "signal.h" |
24 | ||
d0c3d534 OJ |
25 | /* Log an error when sending an unhandled signal to a process. Controlled |
26 | * through debug.exception-trace sysctl. | |
27 | */ | |
28 | ||
e34166ad | 29 | int show_unhandled_signals = 1; |
d0c3d534 | 30 | |
a3f61dc0 BH |
31 | /* |
32 | * Allocate space for the signal frame | |
33 | */ | |
2b3f8e87 | 34 | void __user * get_sigframe(struct k_sigaction *ka, unsigned long sp, |
efbda860 | 35 | size_t frame_size, int is_32) |
a3f61dc0 BH |
36 | { |
37 | unsigned long oldsp, newsp; | |
38 | ||
39 | /* Default to using normal stack */ | |
2b3f8e87 | 40 | oldsp = get_clean_sp(sp, is_32); |
a3f61dc0 BH |
41 | |
42 | /* Check for alt stack */ | |
43 | if ((ka->sa.sa_flags & SA_ONSTACK) && | |
44 | current->sas_ss_size && !on_sig_stack(oldsp)) | |
45 | oldsp = (current->sas_ss_sp + current->sas_ss_size); | |
46 | ||
47 | /* Get aligned frame */ | |
48 | newsp = (oldsp - frame_size) & ~0xFUL; | |
49 | ||
50 | /* Check access */ | |
51 | if (!access_ok(VERIFY_WRITE, (void __user *)newsp, oldsp - newsp)) | |
52 | return NULL; | |
53 | ||
54 | return (void __user *)newsp; | |
55 | } | |
56 | ||
f478f543 CH |
57 | static void check_syscall_restart(struct pt_regs *regs, struct k_sigaction *ka, |
58 | int has_handler) | |
22e38f29 BH |
59 | { |
60 | unsigned long ret = regs->gpr[3]; | |
61 | int restart = 1; | |
62 | ||
63 | /* syscall ? */ | |
64 | if (TRAP(regs) != 0x0C00) | |
65 | return; | |
66 | ||
67 | /* error signalled ? */ | |
68 | if (!(regs->ccr & 0x10000000)) | |
69 | return; | |
70 | ||
71 | switch (ret) { | |
72 | case ERESTART_RESTARTBLOCK: | |
73 | case ERESTARTNOHAND: | |
74 | /* ERESTARTNOHAND means that the syscall should only be | |
75 | * restarted if there was no handler for the signal, and since | |
76 | * we only get here if there is a handler, we dont restart. | |
77 | */ | |
78 | restart = !has_handler; | |
79 | break; | |
80 | case ERESTARTSYS: | |
81 | /* ERESTARTSYS means to restart the syscall if there is no | |
82 | * handler or the handler was registered with SA_RESTART | |
83 | */ | |
84 | restart = !has_handler || (ka->sa.sa_flags & SA_RESTART) != 0; | |
85 | break; | |
86 | case ERESTARTNOINTR: | |
87 | /* ERESTARTNOINTR means that the syscall should be | |
88 | * called again after the signal handler returns. | |
89 | */ | |
90 | break; | |
91 | default: | |
92 | return; | |
93 | } | |
94 | if (restart) { | |
95 | if (ret == ERESTART_RESTARTBLOCK) | |
96 | regs->gpr[0] = __NR_restart_syscall; | |
97 | else | |
98 | regs->gpr[3] = regs->orig_gpr3; | |
99 | regs->nip -= 4; | |
100 | regs->result = 0; | |
101 | } else { | |
102 | regs->result = -EINTR; | |
103 | regs->gpr[3] = EINTR; | |
104 | regs->ccr |= 0x10000000; | |
105 | } | |
106 | } | |
69d15f6b | 107 | |
18b246fa | 108 | static int do_signal(struct pt_regs *regs) |
f478f543 | 109 | { |
b7f9a11a | 110 | sigset_t *oldset = sigmask_to_save(); |
f478f543 CH |
111 | siginfo_t info; |
112 | int signr; | |
113 | struct k_sigaction ka; | |
114 | int ret; | |
115 | int is32 = is_32bit_task(); | |
116 | ||
f478f543 CH |
117 | signr = get_signal_to_deliver(&info, &ka, regs, NULL); |
118 | ||
f478f543 CH |
119 | /* Is there any syscall restart business here ? */ |
120 | check_syscall_restart(regs, &ka, signr > 0); | |
121 | ||
122 | if (signr <= 0) { | |
123 | /* No signal to deliver -- put the saved sigmask back */ | |
51a7b448 | 124 | restore_saved_sigmask(); |
9a81c16b | 125 | regs->trap = 0; |
f478f543 CH |
126 | return 0; /* no signals delivered */ |
127 | } | |
128 | ||
3bffb652 | 129 | #ifndef CONFIG_PPC_ADV_DEBUG_REGS |
f478f543 CH |
130 | /* |
131 | * Reenable the DABR before delivering the signal to | |
132 | * user space. The DABR will have been cleared if it | |
133 | * triggered inside the kernel. | |
134 | */ | |
9422de3e MN |
135 | if (current->thread.hw_brk.address && |
136 | current->thread.hw_brk.type) | |
b9818c33 | 137 | set_breakpoint(¤t->thread.hw_brk); |
d6a61bfc | 138 | #endif |
06532a67 P |
139 | /* Re-enable the breakpoints for the signal stack */ |
140 | thread_change_pc(current, regs); | |
f478f543 CH |
141 | |
142 | if (is32) { | |
f478f543 CH |
143 | if (ka.sa.sa_flags & SA_SIGINFO) |
144 | ret = handle_rt_signal32(signr, &ka, &info, oldset, | |
a3f61dc0 | 145 | regs); |
f478f543 CH |
146 | else |
147 | ret = handle_signal32(signr, &ka, &info, oldset, | |
a3f61dc0 | 148 | regs); |
f478f543 CH |
149 | } else { |
150 | ret = handle_rt_signal64(signr, &ka, &info, oldset, regs); | |
f478f543 CH |
151 | } |
152 | ||
9a81c16b | 153 | regs->trap = 0; |
f478f543 | 154 | if (ret) { |
efee984c | 155 | signal_delivered(signr, &info, &ka, regs, |
6558ba2b | 156 | test_thread_flag(TIF_SINGLESTEP)); |
f478f543 CH |
157 | } |
158 | ||
159 | return ret; | |
160 | } | |
161 | ||
18b246fa | 162 | void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags) |
7d6d637d | 163 | { |
106ed886 LZ |
164 | user_exit(); |
165 | ||
f57d56dd | 166 | if (thread_info_flags & _TIF_UPROBE) |
8b7b80b9 | 167 | uprobe_notify_resume(regs); |
8b7b80b9 | 168 | |
7d6d637d | 169 | if (thread_info_flags & _TIF_SIGPENDING) |
18b246fa | 170 | do_signal(regs); |
7d6d637d RM |
171 | |
172 | if (thread_info_flags & _TIF_NOTIFY_RESUME) { | |
173 | clear_thread_flag(TIF_NOTIFY_RESUME); | |
174 | tracehook_notify_resume(regs); | |
175 | } | |
106ed886 LZ |
176 | |
177 | user_enter(); | |
7d6d637d | 178 | } |
2b3f8e87 MN |
179 | |
180 | unsigned long get_tm_stackpointer(struct pt_regs *regs) | |
181 | { | |
182 | /* When in an active transaction that takes a signal, we need to be | |
183 | * careful with the stack. It's possible that the stack has moved back | |
184 | * up after the tbegin. The obvious case here is when the tbegin is | |
185 | * called inside a function that returns before a tend. In this case, | |
186 | * the stack is part of the checkpointed transactional memory state. | |
187 | * If we write over this non transactionally or in suspend, we are in | |
188 | * trouble because if we get a tm abort, the program counter and stack | |
189 | * pointer will be back at the tbegin but our in memory stack won't be | |
190 | * valid anymore. | |
191 | * | |
192 | * To avoid this, when taking a signal in an active transaction, we | |
193 | * need to use the stack pointer from the checkpointed state, rather | |
194 | * than the speculated state. This ensures that the signal context | |
195 | * (written tm suspended) will be written below the stack required for | |
196 | * the rollback. The transaction is aborted becuase of the treclaim, | |
197 | * so any memory written between the tbegin and the signal will be | |
198 | * rolled back anyway. | |
199 | * | |
200 | * For signals taken in non-TM or suspended mode, we use the | |
201 | * normal/non-checkpointed stack pointer. | |
202 | */ | |
203 | ||
204 | #ifdef CONFIG_PPC_TRANSACTIONAL_MEM | |
205 | if (MSR_TM_ACTIVE(regs->msr)) { | |
d31626f7 | 206 | tm_reclaim_current(TM_CAUSE_SIGNAL); |
2b3f8e87 MN |
207 | if (MSR_TM_TRANSACTIONAL(regs->msr)) |
208 | return current->thread.ckpt_regs.gpr[1]; | |
209 | } | |
210 | #endif | |
211 | return regs->gpr[1]; | |
212 | } |