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-rw-r--r--arch/um/os-Linux/signal.c96
1 files changed, 51 insertions, 45 deletions
diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c
index 583424b9797d..49c113b576b7 100644
--- a/arch/um/os-Linux/signal.c
+++ b/arch/um/os-Linux/signal.c
@@ -1,24 +1,21 @@
1/* 1/*
2 * Copyright (C) 2004 PathScale, Inc 2 * Copyright (C) 2004 PathScale, Inc
3 * Copyright (C) 2004 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Licensed under the GPL 4 * Licensed under the GPL
4 */ 5 */
5 6
6#include <signal.h>
7#include <stdio.h>
8#include <unistd.h>
9#include <stdlib.h> 7#include <stdlib.h>
10#include <errno.h>
11#include <stdarg.h> 8#include <stdarg.h>
12#include <string.h> 9#include <errno.h>
13#include <sys/mman.h> 10#include <signal.h>
14#include "user.h" 11#include <strings.h>
15#include "signal_kern.h"
16#include "sysdep/sigcontext.h"
17#include "sysdep/barrier.h"
18#include "sigcontext.h"
19#include "os.h" 12#include "os.h"
13#include "sysdep/barrier.h"
14#include "sysdep/sigcontext.h"
15#include "user.h"
20 16
21/* These are the asynchronous signals. SIGVTALRM and SIGARLM are handled 17/*
18 * These are the asynchronous signals. SIGVTALRM and SIGARLM are handled
22 * together under SIGVTALRM_BIT. SIGPROF is excluded because we want to 19 * together under SIGVTALRM_BIT. SIGPROF is excluded because we want to
23 * be able to profile all of UML, not just the non-critical sections. If 20 * be able to profile all of UML, not just the non-critical sections. If
24 * profiling is not thread-safe, then that is not my problem. We can disable 21 * profiling is not thread-safe, then that is not my problem. We can disable
@@ -33,7 +30,8 @@
33#define SIGALRM_BIT 2 30#define SIGALRM_BIT 2
34#define SIGALRM_MASK (1 << SIGALRM_BIT) 31#define SIGALRM_MASK (1 << SIGALRM_BIT)
35 32
36/* These are used by both the signal handlers and 33/*
34 * These are used by both the signal handlers and
37 * block/unblock_signals. I don't want modifications cached in a 35 * block/unblock_signals. I don't want modifications cached in a
38 * register - they must go straight to memory. 36 * register - they must go straight to memory.
39 */ 37 */
@@ -45,7 +43,7 @@ void sig_handler(int sig, struct sigcontext *sc)
45 int enabled; 43 int enabled;
46 44
47 enabled = signals_enabled; 45 enabled = signals_enabled;
48 if(!enabled && (sig == SIGIO)){ 46 if (!enabled && (sig == SIGIO)) {
49 pending |= SIGIO_MASK; 47 pending |= SIGIO_MASK;
50 return; 48 return;
51 } 49 }
@@ -61,16 +59,16 @@ static void real_alarm_handler(int sig, struct sigcontext *sc)
61{ 59{
62 struct uml_pt_regs regs; 60 struct uml_pt_regs regs;
63 61
64 if(sig == SIGALRM) 62 if (sig == SIGALRM)
65 switch_timers(0); 63 switch_timers(0);
66 64
67 if(sc != NULL) 65 if (sc != NULL)
68 copy_sc(&regs, sc); 66 copy_sc(&regs, sc);
69 regs.is_user = 0; 67 regs.is_user = 0;
70 unblock_signals(); 68 unblock_signals();
71 timer_handler(sig, &regs); 69 timer_handler(sig, &regs);
72 70
73 if(sig == SIGALRM) 71 if (sig == SIGALRM)
74 switch_timers(1); 72 switch_timers(1);
75} 73}
76 74
@@ -79,8 +77,8 @@ void alarm_handler(int sig, struct sigcontext *sc)
79 int enabled; 77 int enabled;
80 78
81 enabled = signals_enabled; 79 enabled = signals_enabled;
82 if(!signals_enabled){ 80 if (!signals_enabled) {
83 if(sig == SIGVTALRM) 81 if (sig == SIGVTALRM)
84 pending |= SIGVTALRM_MASK; 82 pending |= SIGVTALRM_MASK;
85 else pending |= SIGALRM_MASK; 83 else pending |= SIGALRM_MASK;
86 84
@@ -99,7 +97,7 @@ void set_sigstack(void *sig_stack, int size)
99 .ss_sp = (__ptr_t) sig_stack, 97 .ss_sp = (__ptr_t) sig_stack,
100 .ss_size = size - sizeof(void *) }); 98 .ss_size = size - sizeof(void *) });
101 99
102 if(sigaltstack(&stack, NULL) != 0) 100 if (sigaltstack(&stack, NULL) != 0)
103 panic("enabling signal stack failed, errno = %d\n", errno); 101 panic("enabling signal stack failed, errno = %d\n", errno);
104} 102}
105 103
@@ -109,7 +107,7 @@ void remove_sigstack(void)
109 .ss_sp = NULL, 107 .ss_sp = NULL,
110 .ss_size = 0 }); 108 .ss_size = 0 });
111 109
112 if(sigaltstack(&stack, NULL) != 0) 110 if (sigaltstack(&stack, NULL) != 0)
113 panic("disabling signal stack failed, errno = %d\n", errno); 111 panic("disabling signal stack failed, errno = %d\n", errno);
114} 112}
115 113
@@ -133,26 +131,27 @@ void handle_signal(int sig, struct sigcontext *sc)
133 * with this interrupt. 131 * with this interrupt.
134 */ 132 */
135 bail = to_irq_stack(&pending); 133 bail = to_irq_stack(&pending);
136 if(bail) 134 if (bail)
137 return; 135 return;
138 136
139 nested = pending & 1; 137 nested = pending & 1;
140 pending &= ~1; 138 pending &= ~1;
141 139
142 while((sig = ffs(pending)) != 0){ 140 while ((sig = ffs(pending)) != 0){
143 sig--; 141 sig--;
144 pending &= ~(1 << sig); 142 pending &= ~(1 << sig);
145 (*handlers[sig])(sig, sc); 143 (*handlers[sig])(sig, sc);
146 } 144 }
147 145
148 /* Again, pending comes back with a mask of signals 146 /*
147 * Again, pending comes back with a mask of signals
149 * that arrived while tearing down the stack. If this 148 * that arrived while tearing down the stack. If this
150 * is non-zero, we just go back, set up the stack 149 * is non-zero, we just go back, set up the stack
151 * again, and handle the new interrupts. 150 * again, and handle the new interrupts.
152 */ 151 */
153 if(!nested) 152 if (!nested)
154 pending = from_irq_stack(nested); 153 pending = from_irq_stack(nested);
155 } while(pending); 154 } while (pending);
156} 155}
157 156
158extern void hard_handler(int sig); 157extern void hard_handler(int sig);
@@ -170,18 +169,18 @@ void set_handler(int sig, void (*handler)(int), int flags, ...)
170 sigemptyset(&action.sa_mask); 169 sigemptyset(&action.sa_mask);
171 170
172 va_start(ap, flags); 171 va_start(ap, flags);
173 while((mask = va_arg(ap, int)) != -1) 172 while ((mask = va_arg(ap, int)) != -1)
174 sigaddset(&action.sa_mask, mask); 173 sigaddset(&action.sa_mask, mask);
175 va_end(ap); 174 va_end(ap);
176 175
177 action.sa_flags = flags; 176 action.sa_flags = flags;
178 action.sa_restorer = NULL; 177 action.sa_restorer = NULL;
179 if(sigaction(sig, &action, NULL) < 0) 178 if (sigaction(sig, &action, NULL) < 0)
180 panic("sigaction failed - errno = %d\n", errno); 179 panic("sigaction failed - errno = %d\n", errno);
181 180
182 sigemptyset(&sig_mask); 181 sigemptyset(&sig_mask);
183 sigaddset(&sig_mask, sig); 182 sigaddset(&sig_mask, sig);
184 if(sigprocmask(SIG_UNBLOCK, &sig_mask, NULL) < 0) 183 if (sigprocmask(SIG_UNBLOCK, &sig_mask, NULL) < 0)
185 panic("sigprocmask failed - errno = %d\n", errno); 184 panic("sigprocmask failed - errno = %d\n", errno);
186} 185}
187 186
@@ -192,13 +191,14 @@ int change_sig(int signal, int on)
192 sigemptyset(&sigset); 191 sigemptyset(&sigset);
193 sigaddset(&sigset, signal); 192 sigaddset(&sigset, signal);
194 sigprocmask(on ? SIG_UNBLOCK : SIG_BLOCK, &sigset, &old); 193 sigprocmask(on ? SIG_UNBLOCK : SIG_BLOCK, &sigset, &old);
195 return(!sigismember(&old, signal)); 194 return !sigismember(&old, signal);
196} 195}
197 196
198void block_signals(void) 197void block_signals(void)
199{ 198{
200 signals_enabled = 0; 199 signals_enabled = 0;
201 /* This must return with signals disabled, so this barrier 200 /*
201 * This must return with signals disabled, so this barrier
202 * ensures that writes are flushed out before the return. 202 * ensures that writes are flushed out before the return.
203 * This might matter if gcc figures out how to inline this and 203 * This might matter if gcc figures out how to inline this and
204 * decides to shuffle this code into the caller. 204 * decides to shuffle this code into the caller.
@@ -210,27 +210,31 @@ void unblock_signals(void)
210{ 210{
211 int save_pending; 211 int save_pending;
212 212
213 if(signals_enabled == 1) 213 if (signals_enabled == 1)
214 return; 214 return;
215 215
216 /* We loop because the IRQ handler returns with interrupts off. So, 216 /*
217 * We loop because the IRQ handler returns with interrupts off. So,
217 * interrupts may have arrived and we need to re-enable them and 218 * interrupts may have arrived and we need to re-enable them and
218 * recheck pending. 219 * recheck pending.
219 */ 220 */
220 while(1){ 221 while(1) {
221 /* Save and reset save_pending after enabling signals. This 222 /*
223 * Save and reset save_pending after enabling signals. This
222 * way, pending won't be changed while we're reading it. 224 * way, pending won't be changed while we're reading it.
223 */ 225 */
224 signals_enabled = 1; 226 signals_enabled = 1;
225 227
226 /* Setting signals_enabled and reading pending must 228 /*
229 * Setting signals_enabled and reading pending must
227 * happen in this order. 230 * happen in this order.
228 */ 231 */
229 mb(); 232 mb();
230 233
231 save_pending = pending; 234 save_pending = pending;
232 if(save_pending == 0){ 235 if (save_pending == 0) {
233 /* This must return with signals enabled, so 236 /*
237 * This must return with signals enabled, so
234 * this barrier ensures that writes are 238 * this barrier ensures that writes are
235 * flushed out before the return. This might 239 * flushed out before the return. This might
236 * matter if gcc figures out how to inline 240 * matter if gcc figures out how to inline
@@ -243,24 +247,26 @@ void unblock_signals(void)
243 247
244 pending = 0; 248 pending = 0;
245 249
246 /* We have pending interrupts, so disable signals, as the 250 /*
251 * We have pending interrupts, so disable signals, as the
247 * handlers expect them off when they are called. They will 252 * handlers expect them off when they are called. They will
248 * be enabled again above. 253 * be enabled again above.
249 */ 254 */
250 255
251 signals_enabled = 0; 256 signals_enabled = 0;
252 257
253 /* Deal with SIGIO first because the alarm handler might 258 /*
259 * Deal with SIGIO first because the alarm handler might
254 * schedule, leaving the pending SIGIO stranded until we come 260 * schedule, leaving the pending SIGIO stranded until we come
255 * back here. 261 * back here.
256 */ 262 */
257 if(save_pending & SIGIO_MASK) 263 if (save_pending & SIGIO_MASK)
258 sig_handler_common_skas(SIGIO, NULL); 264 sig_handler_common_skas(SIGIO, NULL);
259 265
260 if(save_pending & SIGALRM_MASK) 266 if (save_pending & SIGALRM_MASK)
261 real_alarm_handler(SIGALRM, NULL); 267 real_alarm_handler(SIGALRM, NULL);
262 268
263 if(save_pending & SIGVTALRM_MASK) 269 if (save_pending & SIGVTALRM_MASK)
264 real_alarm_handler(SIGVTALRM, NULL); 270 real_alarm_handler(SIGVTALRM, NULL);
265 } 271 }
266} 272}
@@ -273,11 +279,11 @@ int get_signals(void)
273int set_signals(int enable) 279int set_signals(int enable)
274{ 280{
275 int ret; 281 int ret;
276 if(signals_enabled == enable) 282 if (signals_enabled == enable)
277 return enable; 283 return enable;
278 284
279 ret = signals_enabled; 285 ret = signals_enabled;
280 if(enable) 286 if (enable)
281 unblock_signals(); 287 unblock_signals();
282 else block_signals(); 288 else block_signals();
283 289