Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2004 PathScale, Inc | |
ba180fd4 | 3 | * Copyright (C) 2004 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) |
1da177e4 LT |
4 | * Licensed under the GPL |
5 | */ | |
6 | ||
0805d89c | 7 | #include <stdlib.h> |
0805d89c | 8 | #include <stdarg.h> |
ba180fd4 JD |
9 | #include <errno.h> |
10 | #include <signal.h> | |
11 | #include <strings.h> | |
75ada8ff | 12 | #include "as-layout.h" |
edea1385 | 13 | #include "kern_util.h" |
cff65c4f | 14 | #include "os.h" |
fe2cc53e | 15 | #include "process.h" |
ba180fd4 JD |
16 | #include "sysdep/barrier.h" |
17 | #include "sysdep/sigcontext.h" | |
18 | #include "user.h" | |
1da177e4 | 19 | |
e6a2d1f7 JD |
20 | /* Copied from linux/compiler-gcc.h since we can't include it directly */ |
21 | #define barrier() __asm__ __volatile__("": : :"memory") | |
22 | ||
75ada8ff JD |
23 | void (*sig_info[NSIG])(int, struct uml_pt_regs *) = { |
24 | [SIGTRAP] = relay_signal, | |
25 | [SIGFPE] = relay_signal, | |
26 | [SIGILL] = relay_signal, | |
27 | [SIGWINCH] = winch, | |
28 | [SIGBUS] = bus_handler, | |
29 | [SIGSEGV] = segv_handler, | |
30 | [SIGIO] = sigio_handler, | |
31 | [SIGVTALRM] = timer_handler }; | |
32 | ||
e6a2d1f7 | 33 | static void sig_handler_common(int sig, struct sigcontext *sc) |
75ada8ff | 34 | { |
e6a2d1f7 JD |
35 | struct uml_pt_regs r; |
36 | int save_errno = errno; | |
75ada8ff | 37 | |
e6a2d1f7 | 38 | r.is_user = 0; |
75ada8ff | 39 | if (sig == SIGSEGV) { |
e6a2d1f7 JD |
40 | /* For segfaults, we want the data from the sigcontext. */ |
41 | copy_sc(&r, sc); | |
42 | GET_FAULTINFO_FROM_SC(r.faultinfo, sc); | |
43 | } | |
75ada8ff | 44 | |
e6a2d1f7 | 45 | /* enable signals if sig isn't IRQ signal */ |
75ada8ff JD |
46 | if ((sig != SIGIO) && (sig != SIGWINCH) && (sig != SIGVTALRM)) |
47 | unblock_signals(); | |
48 | ||
e6a2d1f7 | 49 | (*sig_info[sig])(sig, &r); |
75ada8ff JD |
50 | |
51 | errno = save_errno; | |
75ada8ff JD |
52 | } |
53 | ||
ba180fd4 | 54 | /* |
61b63c55 | 55 | * These are the asynchronous signals. SIGPROF is excluded because we want to |
1d7173ba JD |
56 | * be able to profile all of UML, not just the non-critical sections. If |
57 | * profiling is not thread-safe, then that is not my problem. We can disable | |
58 | * profiling when SMP is enabled in that case. | |
59 | */ | |
60 | #define SIGIO_BIT 0 | |
61 | #define SIGIO_MASK (1 << SIGIO_BIT) | |
62 | ||
63 | #define SIGVTALRM_BIT 1 | |
64 | #define SIGVTALRM_MASK (1 << SIGVTALRM_BIT) | |
65 | ||
fce8c41c | 66 | static int signals_enabled; |
cfef8f34 | 67 | static unsigned int signals_pending; |
1d7173ba | 68 | |
4b84c69b | 69 | void sig_handler(int sig, struct sigcontext *sc) |
1da177e4 | 70 | { |
1d7173ba JD |
71 | int enabled; |
72 | ||
1d7173ba | 73 | enabled = signals_enabled; |
ba180fd4 | 74 | if (!enabled && (sig == SIGIO)) { |
cfef8f34 | 75 | signals_pending |= SIGIO_MASK; |
1d7173ba JD |
76 | return; |
77 | } | |
78 | ||
79 | block_signals(); | |
80 | ||
e6a2d1f7 | 81 | sig_handler_common(sig, sc); |
1d7173ba JD |
82 | |
83 | set_signals(enabled); | |
1da177e4 LT |
84 | } |
85 | ||
61b63c55 | 86 | static void real_alarm_handler(struct sigcontext *sc) |
1da177e4 | 87 | { |
77bf4400 | 88 | struct uml_pt_regs regs; |
2ea5bc5e | 89 | |
ba180fd4 | 90 | if (sc != NULL) |
2ea5bc5e | 91 | copy_sc(®s, sc); |
77bf4400 | 92 | regs.is_user = 0; |
2ea5bc5e | 93 | unblock_signals(); |
61b63c55 | 94 | timer_handler(SIGVTALRM, ®s); |
1d7173ba JD |
95 | } |
96 | ||
4b84c69b | 97 | void alarm_handler(int sig, struct sigcontext *sc) |
1d7173ba | 98 | { |
1d7173ba JD |
99 | int enabled; |
100 | ||
1d7173ba | 101 | enabled = signals_enabled; |
ba180fd4 | 102 | if (!signals_enabled) { |
cfef8f34 | 103 | signals_pending |= SIGVTALRM_MASK; |
1d7173ba JD |
104 | return; |
105 | } | |
106 | ||
107 | block_signals(); | |
108 | ||
61b63c55 | 109 | real_alarm_handler(sc); |
1d7173ba | 110 | set_signals(enabled); |
1da177e4 LT |
111 | } |
112 | ||
78a26e25 JD |
113 | void timer_init(void) |
114 | { | |
115 | set_handler(SIGVTALRM, (__sighandler_t) alarm_handler, | |
61b63c55 | 116 | SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGWINCH, -1); |
78a26e25 JD |
117 | } |
118 | ||
0805d89c GS |
119 | void set_sigstack(void *sig_stack, int size) |
120 | { | |
121 | stack_t stack = ((stack_t) { .ss_flags = 0, | |
122 | .ss_sp = (__ptr_t) sig_stack, | |
123 | .ss_size = size - sizeof(void *) }); | |
124 | ||
ba180fd4 | 125 | if (sigaltstack(&stack, NULL) != 0) |
0805d89c GS |
126 | panic("enabling signal stack failed, errno = %d\n", errno); |
127 | } | |
128 | ||
99764fa4 | 129 | static void (*handlers[_NSIG])(int sig, struct sigcontext *sc); |
4b84c69b | 130 | |
c14b8494 JD |
131 | void handle_signal(int sig, struct sigcontext *sc) |
132 | { | |
508a9274 | 133 | unsigned long pending = 1UL << sig; |
c14b8494 JD |
134 | |
135 | do { | |
136 | int nested, bail; | |
137 | ||
138 | /* | |
139 | * pending comes back with one bit set for each | |
140 | * interrupt that arrived while setting up the stack, | |
141 | * plus a bit for this interrupt, plus the zero bit is | |
142 | * set if this is a nested interrupt. | |
143 | * If bail is true, then we interrupted another | |
144 | * handler setting up the stack. In this case, we | |
145 | * have to return, and the upper handler will deal | |
146 | * with this interrupt. | |
147 | */ | |
508a9274 | 148 | bail = to_irq_stack(&pending); |
ba180fd4 | 149 | if (bail) |
c14b8494 JD |
150 | return; |
151 | ||
152 | nested = pending & 1; | |
153 | pending &= ~1; | |
154 | ||
ba180fd4 | 155 | while ((sig = ffs(pending)) != 0){ |
c14b8494 JD |
156 | sig--; |
157 | pending &= ~(1 << sig); | |
158 | (*handlers[sig])(sig, sc); | |
159 | } | |
160 | ||
ba180fd4 JD |
161 | /* |
162 | * Again, pending comes back with a mask of signals | |
c14b8494 JD |
163 | * that arrived while tearing down the stack. If this |
164 | * is non-zero, we just go back, set up the stack | |
165 | * again, and handle the new interrupts. | |
166 | */ | |
ba180fd4 | 167 | if (!nested) |
c14b8494 | 168 | pending = from_irq_stack(nested); |
ba180fd4 | 169 | } while (pending); |
c14b8494 JD |
170 | } |
171 | ||
4b84c69b JD |
172 | extern void hard_handler(int sig); |
173 | ||
0805d89c GS |
174 | void set_handler(int sig, void (*handler)(int), int flags, ...) |
175 | { | |
176 | struct sigaction action; | |
177 | va_list ap; | |
1d7173ba | 178 | sigset_t sig_mask; |
0805d89c GS |
179 | int mask; |
180 | ||
4b84c69b JD |
181 | handlers[sig] = (void (*)(int, struct sigcontext *)) handler; |
182 | action.sa_handler = hard_handler; | |
183 | ||
0805d89c | 184 | sigemptyset(&action.sa_mask); |
4b84c69b JD |
185 | |
186 | va_start(ap, flags); | |
ba180fd4 | 187 | while ((mask = va_arg(ap, int)) != -1) |
0805d89c | 188 | sigaddset(&action.sa_mask, mask); |
0805d89c | 189 | va_end(ap); |
4b84c69b | 190 | |
e6a2d1f7 JD |
191 | if (sig == SIGSEGV) |
192 | flags |= SA_NODEFER; | |
193 | ||
0805d89c GS |
194 | action.sa_flags = flags; |
195 | action.sa_restorer = NULL; | |
ba180fd4 | 196 | if (sigaction(sig, &action, NULL) < 0) |
1d7173ba JD |
197 | panic("sigaction failed - errno = %d\n", errno); |
198 | ||
199 | sigemptyset(&sig_mask); | |
200 | sigaddset(&sig_mask, sig); | |
ba180fd4 | 201 | if (sigprocmask(SIG_UNBLOCK, &sig_mask, NULL) < 0) |
1d7173ba | 202 | panic("sigprocmask failed - errno = %d\n", errno); |
0805d89c GS |
203 | } |
204 | ||
205 | int change_sig(int signal, int on) | |
206 | { | |
cfef8f34 | 207 | sigset_t sigset; |
0805d89c GS |
208 | |
209 | sigemptyset(&sigset); | |
210 | sigaddset(&sigset, signal); | |
cfef8f34 | 211 | if (sigprocmask(on ? SIG_UNBLOCK : SIG_BLOCK, &sigset, NULL) < 0) |
c9a3072d | 212 | return -errno; |
cfef8f34 JD |
213 | |
214 | return 0; | |
0805d89c GS |
215 | } |
216 | ||
0805d89c GS |
217 | void block_signals(void) |
218 | { | |
1d7173ba | 219 | signals_enabled = 0; |
ba180fd4 JD |
220 | /* |
221 | * This must return with signals disabled, so this barrier | |
53b17332 JD |
222 | * ensures that writes are flushed out before the return. |
223 | * This might matter if gcc figures out how to inline this and | |
224 | * decides to shuffle this code into the caller. | |
225 | */ | |
fce8c41c | 226 | barrier(); |
0805d89c GS |
227 | } |
228 | ||
229 | void unblock_signals(void) | |
230 | { | |
1d7173ba | 231 | int save_pending; |
0805d89c | 232 | |
ba180fd4 | 233 | if (signals_enabled == 1) |
1d7173ba | 234 | return; |
0805d89c | 235 | |
ba180fd4 JD |
236 | /* |
237 | * We loop because the IRQ handler returns with interrupts off. So, | |
1d7173ba | 238 | * interrupts may have arrived and we need to re-enable them and |
cfef8f34 | 239 | * recheck signals_pending. |
1d7173ba | 240 | */ |
5134d8fe | 241 | while (1) { |
ba180fd4 JD |
242 | /* |
243 | * Save and reset save_pending after enabling signals. This | |
cfef8f34 | 244 | * way, signals_pending won't be changed while we're reading it. |
1d7173ba JD |
245 | */ |
246 | signals_enabled = 1; | |
247 | ||
ba180fd4 | 248 | /* |
cfef8f34 | 249 | * Setting signals_enabled and reading signals_pending must |
53b17332 JD |
250 | * happen in this order. |
251 | */ | |
fce8c41c | 252 | barrier(); |
53b17332 | 253 | |
cfef8f34 | 254 | save_pending = signals_pending; |
fce8c41c | 255 | if (save_pending == 0) |
1d7173ba JD |
256 | return; |
257 | ||
cfef8f34 | 258 | signals_pending = 0; |
1d7173ba | 259 | |
ba180fd4 JD |
260 | /* |
261 | * We have pending interrupts, so disable signals, as the | |
1d7173ba JD |
262 | * handlers expect them off when they are called. They will |
263 | * be enabled again above. | |
264 | */ | |
265 | ||
266 | signals_enabled = 0; | |
267 | ||
ba180fd4 JD |
268 | /* |
269 | * Deal with SIGIO first because the alarm handler might | |
1d7173ba JD |
270 | * schedule, leaving the pending SIGIO stranded until we come |
271 | * back here. | |
272 | */ | |
ba180fd4 | 273 | if (save_pending & SIGIO_MASK) |
e6a2d1f7 | 274 | sig_handler_common(SIGIO, NULL); |
1d7173ba | 275 | |
ba180fd4 | 276 | if (save_pending & SIGVTALRM_MASK) |
61b63c55 | 277 | real_alarm_handler(NULL); |
1d7173ba | 278 | } |
0805d89c GS |
279 | } |
280 | ||
281 | int get_signals(void) | |
282 | { | |
1d7173ba | 283 | return signals_enabled; |
0805d89c GS |
284 | } |
285 | ||
286 | int set_signals(int enable) | |
287 | { | |
0805d89c | 288 | int ret; |
ba180fd4 | 289 | if (signals_enabled == enable) |
1d7173ba | 290 | return enable; |
0805d89c | 291 | |
1d7173ba | 292 | ret = signals_enabled; |
ba180fd4 | 293 | if (enable) |
1d7173ba JD |
294 | unblock_signals(); |
295 | else block_signals(); | |
0805d89c | 296 | |
1d7173ba | 297 | return ret; |
0805d89c | 298 | } |