Commit | Line | Data |
---|---|---|
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" |
ba180fd4 JD |
15 | #include "sysdep/barrier.h" |
16 | #include "sysdep/sigcontext.h" | |
17 | #include "user.h" | |
1da177e4 | 18 | |
e6a2d1f7 JD |
19 | /* Copied from linux/compiler-gcc.h since we can't include it directly */ |
20 | #define barrier() __asm__ __volatile__("": : :"memory") | |
21 | ||
75ada8ff JD |
22 | void (*sig_info[NSIG])(int, struct uml_pt_regs *) = { |
23 | [SIGTRAP] = relay_signal, | |
24 | [SIGFPE] = relay_signal, | |
25 | [SIGILL] = relay_signal, | |
26 | [SIGWINCH] = winch, | |
27 | [SIGBUS] = bus_handler, | |
28 | [SIGSEGV] = segv_handler, | |
29 | [SIGIO] = sigio_handler, | |
30 | [SIGVTALRM] = timer_handler }; | |
31 | ||
e6a2d1f7 | 32 | static void sig_handler_common(int sig, struct sigcontext *sc) |
75ada8ff | 33 | { |
e6a2d1f7 JD |
34 | struct uml_pt_regs r; |
35 | int save_errno = errno; | |
75ada8ff | 36 | |
e6a2d1f7 | 37 | r.is_user = 0; |
75ada8ff | 38 | if (sig == SIGSEGV) { |
e6a2d1f7 JD |
39 | /* For segfaults, we want the data from the sigcontext. */ |
40 | copy_sc(&r, sc); | |
41 | GET_FAULTINFO_FROM_SC(r.faultinfo, sc); | |
42 | } | |
75ada8ff | 43 | |
e6a2d1f7 | 44 | /* enable signals if sig isn't IRQ signal */ |
75ada8ff JD |
45 | if ((sig != SIGIO) && (sig != SIGWINCH) && (sig != SIGVTALRM)) |
46 | unblock_signals(); | |
47 | ||
e6a2d1f7 | 48 | (*sig_info[sig])(sig, &r); |
75ada8ff JD |
49 | |
50 | errno = save_errno; | |
75ada8ff JD |
51 | } |
52 | ||
ba180fd4 | 53 | /* |
61b63c55 | 54 | * These are the asynchronous signals. SIGPROF is excluded because we want to |
1d7173ba JD |
55 | * be able to profile all of UML, not just the non-critical sections. If |
56 | * profiling is not thread-safe, then that is not my problem. We can disable | |
57 | * profiling when SMP is enabled in that case. | |
58 | */ | |
59 | #define SIGIO_BIT 0 | |
60 | #define SIGIO_MASK (1 << SIGIO_BIT) | |
61 | ||
62 | #define SIGVTALRM_BIT 1 | |
63 | #define SIGVTALRM_MASK (1 << SIGVTALRM_BIT) | |
64 | ||
fce8c41c JD |
65 | static int signals_enabled; |
66 | static unsigned int pending; | |
1d7173ba | 67 | |
4b84c69b | 68 | void sig_handler(int sig, struct sigcontext *sc) |
1da177e4 | 69 | { |
1d7173ba JD |
70 | int enabled; |
71 | ||
1d7173ba | 72 | enabled = signals_enabled; |
ba180fd4 | 73 | if (!enabled && (sig == SIGIO)) { |
1d7173ba JD |
74 | pending |= SIGIO_MASK; |
75 | return; | |
76 | } | |
77 | ||
78 | block_signals(); | |
79 | ||
e6a2d1f7 | 80 | sig_handler_common(sig, sc); |
1d7173ba JD |
81 | |
82 | set_signals(enabled); | |
1da177e4 LT |
83 | } |
84 | ||
61b63c55 | 85 | static void real_alarm_handler(struct sigcontext *sc) |
1da177e4 | 86 | { |
77bf4400 | 87 | struct uml_pt_regs regs; |
2ea5bc5e | 88 | |
ba180fd4 | 89 | if (sc != NULL) |
2ea5bc5e | 90 | copy_sc(®s, sc); |
77bf4400 | 91 | regs.is_user = 0; |
2ea5bc5e | 92 | unblock_signals(); |
61b63c55 | 93 | timer_handler(SIGVTALRM, ®s); |
1d7173ba JD |
94 | } |
95 | ||
4b84c69b | 96 | void alarm_handler(int sig, struct sigcontext *sc) |
1d7173ba | 97 | { |
1d7173ba JD |
98 | int enabled; |
99 | ||
1d7173ba | 100 | enabled = signals_enabled; |
ba180fd4 | 101 | if (!signals_enabled) { |
61b63c55 | 102 | pending |= SIGVTALRM_MASK; |
1d7173ba JD |
103 | return; |
104 | } | |
105 | ||
106 | block_signals(); | |
107 | ||
61b63c55 | 108 | real_alarm_handler(sc); |
1d7173ba | 109 | set_signals(enabled); |
1da177e4 LT |
110 | } |
111 | ||
78a26e25 JD |
112 | void timer_init(void) |
113 | { | |
114 | set_handler(SIGVTALRM, (__sighandler_t) alarm_handler, | |
61b63c55 | 115 | SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGWINCH, -1); |
78a26e25 JD |
116 | } |
117 | ||
0805d89c GS |
118 | void set_sigstack(void *sig_stack, int size) |
119 | { | |
120 | stack_t stack = ((stack_t) { .ss_flags = 0, | |
121 | .ss_sp = (__ptr_t) sig_stack, | |
122 | .ss_size = size - sizeof(void *) }); | |
123 | ||
ba180fd4 | 124 | if (sigaltstack(&stack, NULL) != 0) |
0805d89c GS |
125 | panic("enabling signal stack failed, errno = %d\n", errno); |
126 | } | |
127 | ||
128 | void remove_sigstack(void) | |
129 | { | |
130 | stack_t stack = ((stack_t) { .ss_flags = SS_DISABLE, | |
131 | .ss_sp = NULL, | |
132 | .ss_size = 0 }); | |
133 | ||
ba180fd4 | 134 | if (sigaltstack(&stack, NULL) != 0) |
0805d89c GS |
135 | panic("disabling signal stack failed, errno = %d\n", errno); |
136 | } | |
137 | ||
4b84c69b JD |
138 | void (*handlers[_NSIG])(int sig, struct sigcontext *sc); |
139 | ||
c14b8494 JD |
140 | void handle_signal(int sig, struct sigcontext *sc) |
141 | { | |
508a9274 | 142 | unsigned long pending = 1UL << sig; |
c14b8494 JD |
143 | |
144 | do { | |
145 | int nested, bail; | |
146 | ||
147 | /* | |
148 | * pending comes back with one bit set for each | |
149 | * interrupt that arrived while setting up the stack, | |
150 | * plus a bit for this interrupt, plus the zero bit is | |
151 | * set if this is a nested interrupt. | |
152 | * If bail is true, then we interrupted another | |
153 | * handler setting up the stack. In this case, we | |
154 | * have to return, and the upper handler will deal | |
155 | * with this interrupt. | |
156 | */ | |
508a9274 | 157 | bail = to_irq_stack(&pending); |
ba180fd4 | 158 | if (bail) |
c14b8494 JD |
159 | return; |
160 | ||
161 | nested = pending & 1; | |
162 | pending &= ~1; | |
163 | ||
ba180fd4 | 164 | while ((sig = ffs(pending)) != 0){ |
c14b8494 JD |
165 | sig--; |
166 | pending &= ~(1 << sig); | |
167 | (*handlers[sig])(sig, sc); | |
168 | } | |
169 | ||
ba180fd4 JD |
170 | /* |
171 | * Again, pending comes back with a mask of signals | |
c14b8494 JD |
172 | * that arrived while tearing down the stack. If this |
173 | * is non-zero, we just go back, set up the stack | |
174 | * again, and handle the new interrupts. | |
175 | */ | |
ba180fd4 | 176 | if (!nested) |
c14b8494 | 177 | pending = from_irq_stack(nested); |
ba180fd4 | 178 | } while (pending); |
c14b8494 JD |
179 | } |
180 | ||
4b84c69b JD |
181 | extern void hard_handler(int sig); |
182 | ||
0805d89c GS |
183 | void set_handler(int sig, void (*handler)(int), int flags, ...) |
184 | { | |
185 | struct sigaction action; | |
186 | va_list ap; | |
1d7173ba | 187 | sigset_t sig_mask; |
0805d89c GS |
188 | int mask; |
189 | ||
4b84c69b JD |
190 | handlers[sig] = (void (*)(int, struct sigcontext *)) handler; |
191 | action.sa_handler = hard_handler; | |
192 | ||
0805d89c | 193 | sigemptyset(&action.sa_mask); |
4b84c69b JD |
194 | |
195 | va_start(ap, flags); | |
ba180fd4 | 196 | while ((mask = va_arg(ap, int)) != -1) |
0805d89c | 197 | sigaddset(&action.sa_mask, mask); |
0805d89c | 198 | va_end(ap); |
4b84c69b | 199 | |
e6a2d1f7 JD |
200 | if (sig == SIGSEGV) |
201 | flags |= SA_NODEFER; | |
202 | ||
0805d89c GS |
203 | action.sa_flags = flags; |
204 | action.sa_restorer = NULL; | |
ba180fd4 | 205 | if (sigaction(sig, &action, NULL) < 0) |
1d7173ba JD |
206 | panic("sigaction failed - errno = %d\n", errno); |
207 | ||
208 | sigemptyset(&sig_mask); | |
209 | sigaddset(&sig_mask, sig); | |
ba180fd4 | 210 | if (sigprocmask(SIG_UNBLOCK, &sig_mask, NULL) < 0) |
1d7173ba | 211 | panic("sigprocmask failed - errno = %d\n", errno); |
0805d89c GS |
212 | } |
213 | ||
214 | int change_sig(int signal, int on) | |
215 | { | |
216 | sigset_t sigset, old; | |
217 | ||
218 | sigemptyset(&sigset); | |
219 | sigaddset(&sigset, signal); | |
c9a3072d WC |
220 | if (sigprocmask(on ? SIG_UNBLOCK : SIG_BLOCK, &sigset, &old) < 0) |
221 | return -errno; | |
ba180fd4 | 222 | return !sigismember(&old, signal); |
0805d89c GS |
223 | } |
224 | ||
0805d89c GS |
225 | void block_signals(void) |
226 | { | |
1d7173ba | 227 | signals_enabled = 0; |
ba180fd4 JD |
228 | /* |
229 | * This must return with signals disabled, so this barrier | |
53b17332 JD |
230 | * ensures that writes are flushed out before the return. |
231 | * This might matter if gcc figures out how to inline this and | |
232 | * decides to shuffle this code into the caller. | |
233 | */ | |
fce8c41c | 234 | barrier(); |
0805d89c GS |
235 | } |
236 | ||
237 | void unblock_signals(void) | |
238 | { | |
1d7173ba | 239 | int save_pending; |
0805d89c | 240 | |
ba180fd4 | 241 | if (signals_enabled == 1) |
1d7173ba | 242 | return; |
0805d89c | 243 | |
ba180fd4 JD |
244 | /* |
245 | * We loop because the IRQ handler returns with interrupts off. So, | |
1d7173ba JD |
246 | * interrupts may have arrived and we need to re-enable them and |
247 | * recheck pending. | |
248 | */ | |
ba180fd4 JD |
249 | while(1) { |
250 | /* | |
251 | * Save and reset save_pending after enabling signals. This | |
1d7173ba JD |
252 | * way, pending won't be changed while we're reading it. |
253 | */ | |
254 | signals_enabled = 1; | |
255 | ||
ba180fd4 JD |
256 | /* |
257 | * Setting signals_enabled and reading pending must | |
53b17332 JD |
258 | * happen in this order. |
259 | */ | |
fce8c41c | 260 | barrier(); |
53b17332 | 261 | |
1d7173ba | 262 | save_pending = pending; |
fce8c41c | 263 | if (save_pending == 0) |
1d7173ba JD |
264 | return; |
265 | ||
266 | pending = 0; | |
267 | ||
ba180fd4 JD |
268 | /* |
269 | * We have pending interrupts, so disable signals, as the | |
1d7173ba JD |
270 | * handlers expect them off when they are called. They will |
271 | * be enabled again above. | |
272 | */ | |
273 | ||
274 | signals_enabled = 0; | |
275 | ||
ba180fd4 JD |
276 | /* |
277 | * Deal with SIGIO first because the alarm handler might | |
1d7173ba JD |
278 | * schedule, leaving the pending SIGIO stranded until we come |
279 | * back here. | |
280 | */ | |
ba180fd4 | 281 | if (save_pending & SIGIO_MASK) |
e6a2d1f7 | 282 | sig_handler_common(SIGIO, NULL); |
1d7173ba | 283 | |
ba180fd4 | 284 | if (save_pending & SIGVTALRM_MASK) |
61b63c55 | 285 | real_alarm_handler(NULL); |
1d7173ba | 286 | } |
0805d89c GS |
287 | } |
288 | ||
289 | int get_signals(void) | |
290 | { | |
1d7173ba | 291 | return signals_enabled; |
0805d89c GS |
292 | } |
293 | ||
294 | int set_signals(int enable) | |
295 | { | |
0805d89c | 296 | int ret; |
ba180fd4 | 297 | if (signals_enabled == enable) |
1d7173ba | 298 | return enable; |
0805d89c | 299 | |
1d7173ba | 300 | ret = signals_enabled; |
ba180fd4 | 301 | if (enable) |
1d7173ba JD |
302 | unblock_signals(); |
303 | else block_signals(); | |
0805d89c | 304 | |
1d7173ba | 305 | return ret; |
0805d89c | 306 | } |