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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 | */ | |
059ade65 | 34 | void __user *get_sigframe(struct ksignal *ksig, 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); |
059ade65 | 41 | oldsp = sigsp(oldsp, ksig); |
a3f61dc0 BH |
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 CH |
51 | static void check_syscall_restart(struct pt_regs *regs, struct k_sigaction *ka, |
52 | int has_handler) | |
22e38f29 BH |
53 | { |
54 | unsigned long ret = regs->gpr[3]; | |
55 | int restart = 1; | |
56 | ||
57 | /* syscall ? */ | |
58 | if (TRAP(regs) != 0x0C00) | |
59 | return; | |
60 | ||
61 | /* error signalled ? */ | |
62 | if (!(regs->ccr & 0x10000000)) | |
63 | return; | |
64 | ||
65 | switch (ret) { | |
66 | case ERESTART_RESTARTBLOCK: | |
67 | case ERESTARTNOHAND: | |
68 | /* ERESTARTNOHAND means that the syscall should only be | |
69 | * restarted if there was no handler for the signal, and since | |
70 | * we only get here if there is a handler, we dont restart. | |
71 | */ | |
72 | restart = !has_handler; | |
73 | break; | |
74 | case ERESTARTSYS: | |
75 | /* ERESTARTSYS means to restart the syscall if there is no | |
76 | * handler or the handler was registered with SA_RESTART | |
77 | */ | |
78 | restart = !has_handler || (ka->sa.sa_flags & SA_RESTART) != 0; | |
79 | break; | |
80 | case ERESTARTNOINTR: | |
81 | /* ERESTARTNOINTR means that the syscall should be | |
82 | * called again after the signal handler returns. | |
83 | */ | |
84 | break; | |
85 | default: | |
86 | return; | |
87 | } | |
88 | if (restart) { | |
89 | if (ret == ERESTART_RESTARTBLOCK) | |
90 | regs->gpr[0] = __NR_restart_syscall; | |
91 | else | |
92 | regs->gpr[3] = regs->orig_gpr3; | |
93 | regs->nip -= 4; | |
94 | regs->result = 0; | |
95 | } else { | |
96 | regs->result = -EINTR; | |
97 | regs->gpr[3] = EINTR; | |
98 | regs->ccr |= 0x10000000; | |
99 | } | |
100 | } | |
69d15f6b | 101 | |
129b69df | 102 | static void do_signal(struct pt_regs *regs) |
f478f543 | 103 | { |
b7f9a11a | 104 | sigset_t *oldset = sigmask_to_save(); |
129b69df | 105 | struct ksignal ksig; |
f478f543 CH |
106 | int ret; |
107 | int is32 = is_32bit_task(); | |
108 | ||
129b69df | 109 | get_signal(&ksig); |
f478f543 | 110 | |
f478f543 | 111 | /* Is there any syscall restart business here ? */ |
129b69df | 112 | check_syscall_restart(regs, &ksig.ka, ksig.sig > 0); |
f478f543 | 113 | |
129b69df | 114 | if (ksig.sig <= 0) { |
f478f543 | 115 | /* No signal to deliver -- put the saved sigmask back */ |
51a7b448 | 116 | restore_saved_sigmask(); |
9a81c16b | 117 | regs->trap = 0; |
129b69df | 118 | return; /* no signals delivered */ |
f478f543 CH |
119 | } |
120 | ||
3bffb652 | 121 | #ifndef CONFIG_PPC_ADV_DEBUG_REGS |
f478f543 CH |
122 | /* |
123 | * Reenable the DABR before delivering the signal to | |
124 | * user space. The DABR will have been cleared if it | |
125 | * triggered inside the kernel. | |
126 | */ | |
9422de3e MN |
127 | if (current->thread.hw_brk.address && |
128 | current->thread.hw_brk.type) | |
21f58507 | 129 | __set_breakpoint(¤t->thread.hw_brk); |
d6a61bfc | 130 | #endif |
06532a67 P |
131 | /* Re-enable the breakpoints for the signal stack */ |
132 | thread_change_pc(current, regs); | |
f478f543 CH |
133 | |
134 | if (is32) { | |
129b69df RW |
135 | if (ksig.ka.sa.sa_flags & SA_SIGINFO) |
136 | ret = handle_rt_signal32(&ksig, oldset, regs); | |
f478f543 | 137 | else |
129b69df | 138 | ret = handle_signal32(&ksig, oldset, regs); |
f478f543 | 139 | } else { |
129b69df | 140 | ret = handle_rt_signal64(&ksig, oldset, regs); |
f478f543 CH |
141 | } |
142 | ||
9a81c16b | 143 | regs->trap = 0; |
129b69df | 144 | signal_setup_done(ret, &ksig, test_thread_flag(TIF_SINGLESTEP)); |
f478f543 CH |
145 | } |
146 | ||
18b246fa | 147 | void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags) |
7d6d637d | 148 | { |
106ed886 LZ |
149 | user_exit(); |
150 | ||
f57d56dd | 151 | if (thread_info_flags & _TIF_UPROBE) |
8b7b80b9 | 152 | uprobe_notify_resume(regs); |
8b7b80b9 | 153 | |
7d6d637d | 154 | if (thread_info_flags & _TIF_SIGPENDING) |
18b246fa | 155 | do_signal(regs); |
7d6d637d RM |
156 | |
157 | if (thread_info_flags & _TIF_NOTIFY_RESUME) { | |
158 | clear_thread_flag(TIF_NOTIFY_RESUME); | |
159 | tracehook_notify_resume(regs); | |
160 | } | |
106ed886 LZ |
161 | |
162 | user_enter(); | |
7d6d637d | 163 | } |
2b3f8e87 MN |
164 | |
165 | unsigned long get_tm_stackpointer(struct pt_regs *regs) | |
166 | { | |
167 | /* When in an active transaction that takes a signal, we need to be | |
168 | * careful with the stack. It's possible that the stack has moved back | |
169 | * up after the tbegin. The obvious case here is when the tbegin is | |
170 | * called inside a function that returns before a tend. In this case, | |
171 | * the stack is part of the checkpointed transactional memory state. | |
172 | * If we write over this non transactionally or in suspend, we are in | |
173 | * trouble because if we get a tm abort, the program counter and stack | |
174 | * pointer will be back at the tbegin but our in memory stack won't be | |
175 | * valid anymore. | |
176 | * | |
177 | * To avoid this, when taking a signal in an active transaction, we | |
178 | * need to use the stack pointer from the checkpointed state, rather | |
179 | * than the speculated state. This ensures that the signal context | |
180 | * (written tm suspended) will be written below the stack required for | |
181 | * the rollback. The transaction is aborted becuase of the treclaim, | |
182 | * so any memory written between the tbegin and the signal will be | |
183 | * rolled back anyway. | |
184 | * | |
185 | * For signals taken in non-TM or suspended mode, we use the | |
186 | * normal/non-checkpointed stack pointer. | |
187 | */ | |
188 | ||
189 | #ifdef CONFIG_PPC_TRANSACTIONAL_MEM | |
190 | if (MSR_TM_ACTIVE(regs->msr)) { | |
d31626f7 | 191 | tm_reclaim_current(TM_CAUSE_SIGNAL); |
2b3f8e87 MN |
192 | if (MSR_TM_TRANSACTIONAL(regs->msr)) |
193 | return current->thread.ckpt_regs.gpr[1]; | |
194 | } | |
195 | #endif | |
196 | return regs->gpr[1]; | |
197 | } |