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22e38f29 BH |
1 | /* |
2 | * Common signal handling code for both 32 and 64 bits | |
3 | * | |
446957ba | 4 | * Copyright (c) 2007 Benjamin Herrenschmidt, IBM Corporation |
22e38f29 BH |
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> |
a768f784 | 17 | #include <linux/livepatch.h> |
06532a67 | 18 | #include <asm/hw_breakpoint.h> |
7c0f6ba6 | 19 | #include <linux/uaccess.h> |
22e38f29 | 20 | #include <asm/unistd.h> |
ae3a197e | 21 | #include <asm/debug.h> |
2b3f8e87 | 22 | #include <asm/tm.h> |
22e38f29 | 23 | |
db277e9a CH |
24 | #include "signal.h" |
25 | ||
d0c3d534 OJ |
26 | /* Log an error when sending an unhandled signal to a process. Controlled |
27 | * through debug.exception-trace sysctl. | |
28 | */ | |
29 | ||
e34166ad | 30 | int show_unhandled_signals = 1; |
d0c3d534 | 31 | |
a3f61dc0 BH |
32 | /* |
33 | * Allocate space for the signal frame | |
34 | */ | |
059ade65 | 35 | void __user *get_sigframe(struct ksignal *ksig, unsigned long sp, |
efbda860 | 36 | size_t frame_size, int is_32) |
a3f61dc0 BH |
37 | { |
38 | unsigned long oldsp, newsp; | |
39 | ||
40 | /* Default to using normal stack */ | |
2b3f8e87 | 41 | oldsp = get_clean_sp(sp, is_32); |
059ade65 | 42 | oldsp = sigsp(oldsp, ksig); |
a3f61dc0 BH |
43 | newsp = (oldsp - frame_size) & ~0xFUL; |
44 | ||
45 | /* Check access */ | |
46 | if (!access_ok(VERIFY_WRITE, (void __user *)newsp, oldsp - newsp)) | |
47 | return NULL; | |
48 | ||
49 | return (void __user *)newsp; | |
50 | } | |
51 | ||
f478f543 CH |
52 | static void check_syscall_restart(struct pt_regs *regs, struct k_sigaction *ka, |
53 | int has_handler) | |
22e38f29 BH |
54 | { |
55 | unsigned long ret = regs->gpr[3]; | |
56 | int restart = 1; | |
57 | ||
58 | /* syscall ? */ | |
59 | if (TRAP(regs) != 0x0C00) | |
60 | return; | |
61 | ||
62 | /* error signalled ? */ | |
63 | if (!(regs->ccr & 0x10000000)) | |
64 | return; | |
65 | ||
66 | switch (ret) { | |
67 | case ERESTART_RESTARTBLOCK: | |
68 | case ERESTARTNOHAND: | |
69 | /* ERESTARTNOHAND means that the syscall should only be | |
70 | * restarted if there was no handler for the signal, and since | |
71 | * we only get here if there is a handler, we dont restart. | |
72 | */ | |
73 | restart = !has_handler; | |
74 | break; | |
75 | case ERESTARTSYS: | |
76 | /* ERESTARTSYS means to restart the syscall if there is no | |
77 | * handler or the handler was registered with SA_RESTART | |
78 | */ | |
79 | restart = !has_handler || (ka->sa.sa_flags & SA_RESTART) != 0; | |
80 | break; | |
81 | case ERESTARTNOINTR: | |
82 | /* ERESTARTNOINTR means that the syscall should be | |
83 | * called again after the signal handler returns. | |
84 | */ | |
85 | break; | |
86 | default: | |
87 | return; | |
88 | } | |
89 | if (restart) { | |
90 | if (ret == ERESTART_RESTARTBLOCK) | |
91 | regs->gpr[0] = __NR_restart_syscall; | |
92 | else | |
93 | regs->gpr[3] = regs->orig_gpr3; | |
94 | regs->nip -= 4; | |
95 | regs->result = 0; | |
96 | } else { | |
97 | regs->result = -EINTR; | |
98 | regs->gpr[3] = EINTR; | |
99 | regs->ccr |= 0x10000000; | |
100 | } | |
101 | } | |
69d15f6b | 102 | |
d1199431 | 103 | static void do_signal(struct task_struct *tsk) |
f478f543 | 104 | { |
b7f9a11a | 105 | sigset_t *oldset = sigmask_to_save(); |
129b69df | 106 | struct ksignal ksig; |
f478f543 CH |
107 | int ret; |
108 | int is32 = is_32bit_task(); | |
109 | ||
d1199431 CB |
110 | BUG_ON(tsk != current); |
111 | ||
129b69df | 112 | get_signal(&ksig); |
f478f543 | 113 | |
f478f543 | 114 | /* Is there any syscall restart business here ? */ |
d1199431 | 115 | check_syscall_restart(tsk->thread.regs, &ksig.ka, ksig.sig > 0); |
f478f543 | 116 | |
129b69df | 117 | if (ksig.sig <= 0) { |
f478f543 | 118 | /* No signal to deliver -- put the saved sigmask back */ |
51a7b448 | 119 | restore_saved_sigmask(); |
d1199431 | 120 | tsk->thread.regs->trap = 0; |
129b69df | 121 | return; /* no signals delivered */ |
f478f543 CH |
122 | } |
123 | ||
3bffb652 | 124 | #ifndef CONFIG_PPC_ADV_DEBUG_REGS |
f478f543 CH |
125 | /* |
126 | * Reenable the DABR before delivering the signal to | |
127 | * user space. The DABR will have been cleared if it | |
128 | * triggered inside the kernel. | |
129 | */ | |
d1199431 CB |
130 | if (tsk->thread.hw_brk.address && tsk->thread.hw_brk.type) |
131 | __set_breakpoint(&tsk->thread.hw_brk); | |
d6a61bfc | 132 | #endif |
06532a67 | 133 | /* Re-enable the breakpoints for the signal stack */ |
d1199431 | 134 | thread_change_pc(tsk, tsk->thread.regs); |
f478f543 CH |
135 | |
136 | if (is32) { | |
129b69df | 137 | if (ksig.ka.sa.sa_flags & SA_SIGINFO) |
d1199431 | 138 | ret = handle_rt_signal32(&ksig, oldset, tsk); |
f478f543 | 139 | else |
d1199431 | 140 | ret = handle_signal32(&ksig, oldset, tsk); |
f478f543 | 141 | } else { |
d1199431 | 142 | ret = handle_rt_signal64(&ksig, oldset, tsk); |
f478f543 CH |
143 | } |
144 | ||
d1199431 | 145 | tsk->thread.regs->trap = 0; |
129b69df | 146 | signal_setup_done(ret, &ksig, test_thread_flag(TIF_SINGLESTEP)); |
f478f543 CH |
147 | } |
148 | ||
18b246fa | 149 | void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags) |
7d6d637d | 150 | { |
106ed886 LZ |
151 | user_exit(); |
152 | ||
f57d56dd | 153 | if (thread_info_flags & _TIF_UPROBE) |
8b7b80b9 | 154 | uprobe_notify_resume(regs); |
8b7b80b9 | 155 | |
d1199431 CB |
156 | if (thread_info_flags & _TIF_SIGPENDING) { |
157 | BUG_ON(regs != current->thread.regs); | |
158 | do_signal(current); | |
159 | } | |
7d6d637d RM |
160 | |
161 | if (thread_info_flags & _TIF_NOTIFY_RESUME) { | |
162 | clear_thread_flag(TIF_NOTIFY_RESUME); | |
163 | tracehook_notify_resume(regs); | |
164 | } | |
106ed886 | 165 | |
a768f784 JP |
166 | if (thread_info_flags & _TIF_PATCH_PENDING) |
167 | klp_update_patch_state(current); | |
168 | ||
106ed886 | 169 | user_enter(); |
7d6d637d | 170 | } |
2b3f8e87 | 171 | |
d1199431 | 172 | unsigned long get_tm_stackpointer(struct task_struct *tsk) |
2b3f8e87 MN |
173 | { |
174 | /* When in an active transaction that takes a signal, we need to be | |
175 | * careful with the stack. It's possible that the stack has moved back | |
176 | * up after the tbegin. The obvious case here is when the tbegin is | |
177 | * called inside a function that returns before a tend. In this case, | |
178 | * the stack is part of the checkpointed transactional memory state. | |
179 | * If we write over this non transactionally or in suspend, we are in | |
180 | * trouble because if we get a tm abort, the program counter and stack | |
181 | * pointer will be back at the tbegin but our in memory stack won't be | |
182 | * valid anymore. | |
183 | * | |
184 | * To avoid this, when taking a signal in an active transaction, we | |
185 | * need to use the stack pointer from the checkpointed state, rather | |
186 | * than the speculated state. This ensures that the signal context | |
187 | * (written tm suspended) will be written below the stack required for | |
446957ba | 188 | * the rollback. The transaction is aborted because of the treclaim, |
2b3f8e87 MN |
189 | * so any memory written between the tbegin and the signal will be |
190 | * rolled back anyway. | |
191 | * | |
192 | * For signals taken in non-TM or suspended mode, we use the | |
193 | * normal/non-checkpointed stack pointer. | |
194 | */ | |
195 | ||
196 | #ifdef CONFIG_PPC_TRANSACTIONAL_MEM | |
d1199431 CB |
197 | BUG_ON(tsk != current); |
198 | ||
199 | if (MSR_TM_ACTIVE(tsk->thread.regs->msr)) { | |
d31626f7 | 200 | tm_reclaim_current(TM_CAUSE_SIGNAL); |
d1199431 CB |
201 | if (MSR_TM_TRANSACTIONAL(tsk->thread.regs->msr)) |
202 | return tsk->thread.ckpt_regs.gpr[1]; | |
2b3f8e87 MN |
203 | } |
204 | #endif | |
d1199431 | 205 | return tsk->thread.regs->gpr[1]; |
2b3f8e87 | 206 | } |