2 * Copyright (C) 2004 PathScale, Inc
3 * Licensed under the GPL
15 #include "signal_kern.h"
16 #include "sysdep/sigcontext.h"
17 #include "sysdep/barrier.h"
18 #include "sigcontext.h"
22 /* These are the asynchronous signals. SIGVTALRM and SIGARLM are handled
23 * together under SIGVTALRM_BIT. SIGPROF is excluded because we want to
24 * be able to profile all of UML, not just the non-critical sections. If
25 * profiling is not thread-safe, then that is not my problem. We can disable
26 * profiling when SMP is enabled in that case.
29 #define SIGIO_MASK (1 << SIGIO_BIT)
31 #define SIGVTALRM_BIT 1
32 #define SIGVTALRM_MASK (1 << SIGVTALRM_BIT)
35 #define SIGALRM_MASK (1 << SIGALRM_BIT)
37 /* These are used by both the signal handlers and
38 * block/unblock_signals. I don't want modifications cached in a
39 * register - they must go straight to memory.
41 static volatile int signals_enabled
= 1;
42 static volatile int pending
= 0;
44 void sig_handler(int sig
, struct sigcontext
*sc
)
48 enabled
= signals_enabled
;
49 if(!enabled
&& (sig
== SIGIO
)){
50 pending
|= SIGIO_MASK
;
56 CHOOSE_MODE_PROC(sig_handler_common_tt
, sig_handler_common_skas
,
62 static void real_alarm_handler(int sig
, struct sigcontext
*sc
)
64 union uml_pt_regs regs
;
71 regs
.skas
.is_user
= 0;
73 timer_handler(sig
, ®s
);
79 void alarm_handler(int sig
, struct sigcontext
*sc
)
83 enabled
= signals_enabled
;
86 pending
|= SIGVTALRM_MASK
;
87 else pending
|= SIGALRM_MASK
;
94 real_alarm_handler(sig
, sc
);
98 void set_sigstack(void *sig_stack
, int size
)
100 stack_t stack
= ((stack_t
) { .ss_flags
= 0,
101 .ss_sp
= (__ptr_t
) sig_stack
,
102 .ss_size
= size
- sizeof(void *) });
104 if(sigaltstack(&stack
, NULL
) != 0)
105 panic("enabling signal stack failed, errno = %d\n", errno
);
108 void remove_sigstack(void)
110 stack_t stack
= ((stack_t
) { .ss_flags
= SS_DISABLE
,
114 if(sigaltstack(&stack
, NULL
) != 0)
115 panic("disabling signal stack failed, errno = %d\n", errno
);
118 void (*handlers
[_NSIG
])(int sig
, struct sigcontext
*sc
);
120 extern void hard_handler(int sig
);
122 void set_handler(int sig
, void (*handler
)(int), int flags
, ...)
124 struct sigaction action
;
129 handlers
[sig
] = (void (*)(int, struct sigcontext
*)) handler
;
130 action
.sa_handler
= hard_handler
;
132 sigemptyset(&action
.sa_mask
);
135 while((mask
= va_arg(ap
, int)) != -1)
136 sigaddset(&action
.sa_mask
, mask
);
139 action
.sa_flags
= flags
;
140 action
.sa_restorer
= NULL
;
141 if(sigaction(sig
, &action
, NULL
) < 0)
142 panic("sigaction failed - errno = %d\n", errno
);
144 sigemptyset(&sig_mask
);
145 sigaddset(&sig_mask
, sig
);
146 if(sigprocmask(SIG_UNBLOCK
, &sig_mask
, NULL
) < 0)
147 panic("sigprocmask failed - errno = %d\n", errno
);
150 int change_sig(int signal
, int on
)
152 sigset_t sigset
, old
;
154 sigemptyset(&sigset
);
155 sigaddset(&sigset
, signal
);
156 sigprocmask(on
? SIG_UNBLOCK
: SIG_BLOCK
, &sigset
, &old
);
157 return(!sigismember(&old
, signal
));
160 void block_signals(void)
163 /* This must return with signals disabled, so this barrier
164 * ensures that writes are flushed out before the return.
165 * This might matter if gcc figures out how to inline this and
166 * decides to shuffle this code into the caller.
171 void unblock_signals(void)
175 if(signals_enabled
== 1)
178 /* We loop because the IRQ handler returns with interrupts off. So,
179 * interrupts may have arrived and we need to re-enable them and
183 /* Save and reset save_pending after enabling signals. This
184 * way, pending won't be changed while we're reading it.
188 /* Setting signals_enabled and reading pending must
189 * happen in this order.
193 save_pending
= pending
;
194 if(save_pending
== 0){
195 /* This must return with signals enabled, so
196 * this barrier ensures that writes are
197 * flushed out before the return. This might
198 * matter if gcc figures out how to inline
199 * this (unlikely, given its size) and decides
200 * to shuffle this code into the caller.
208 /* We have pending interrupts, so disable signals, as the
209 * handlers expect them off when they are called. They will
210 * be enabled again above.
215 /* Deal with SIGIO first because the alarm handler might
216 * schedule, leaving the pending SIGIO stranded until we come
219 if(save_pending
& SIGIO_MASK
)
220 CHOOSE_MODE_PROC(sig_handler_common_tt
,
221 sig_handler_common_skas
, SIGIO
, NULL
);
223 if(save_pending
& SIGALRM_MASK
)
224 real_alarm_handler(SIGALRM
, NULL
);
226 if(save_pending
& SIGVTALRM_MASK
)
227 real_alarm_handler(SIGVTALRM
, NULL
);
231 int get_signals(void)
233 return signals_enabled
;
236 int set_signals(int enable
)
239 if(signals_enabled
== enable
)
242 ret
= signals_enabled
;
245 else block_signals();