#include <stdarg.h>
#include <string.h>
#include <sys/mman.h>
-#include "user_util.h"
#include "user.h"
#include "signal_kern.h"
#include "sysdep/sigcontext.h"
-#include "sysdep/signal.h"
+#include "sysdep/barrier.h"
#include "sigcontext.h"
#include "mode.h"
#include "os.h"
#define SIGALRM_BIT 2
#define SIGALRM_MASK (1 << SIGALRM_BIT)
-static int signals_enabled = 1;
-static int pending = 0;
+/* These are used by both the signal handlers and
+ * block/unblock_signals. I don't want modifications cached in a
+ * register - they must go straight to memory.
+ */
+static volatile int signals_enabled = 1;
+static volatile int pending = 0;
-void sig_handler(ARCH_SIGHDLR_PARAM)
+void sig_handler(int sig, struct sigcontext *sc)
{
- struct sigcontext *sc;
int enabled;
- /* Must be the first thing that this handler does - x86_64 stores
- * the sigcontext in %rdx, and we need to save it before it has a
- * chance to get trashed.
- */
-
- ARCH_GET_SIGCONTEXT(sc, sig);
-
enabled = signals_enabled;
if(!enabled && (sig == SIGIO)){
pending |= SIGIO_MASK;
set_signals(enabled);
}
-extern int timer_irq_inited;
-
static void real_alarm_handler(int sig, struct sigcontext *sc)
{
- if(!timer_irq_inited){
- signals_enabled = 1;
- return;
- }
+ union uml_pt_regs regs;
if(sig == SIGALRM)
switch_timers(0);
- CHOOSE_MODE_PROC(sig_handler_common_tt, sig_handler_common_skas,
- sig, sc);
+ if(sc != NULL)
+ copy_sc(®s, sc);
+ regs.skas.is_user = 0;
+ unblock_signals();
+ timer_handler(sig, ®s);
if(sig == SIGALRM)
switch_timers(1);
-
}
-void alarm_handler(ARCH_SIGHDLR_PARAM)
+void alarm_handler(int sig, struct sigcontext *sc)
{
- struct sigcontext *sc;
int enabled;
- ARCH_GET_SIGCONTEXT(sc, sig);
-
enabled = signals_enabled;
if(!signals_enabled){
if(sig == SIGVTALRM)
set_signals(enabled);
}
-extern void do_boot_timer_handler(struct sigcontext * sc);
-
-void boot_timer_handler(ARCH_SIGHDLR_PARAM)
-{
- struct sigcontext *sc;
- int enabled;
-
- ARCH_GET_SIGCONTEXT(sc, sig);
-
- enabled = signals_enabled;
- if(!enabled){
- if(sig == SIGVTALRM)
- pending |= SIGVTALRM_MASK;
- else pending |= SIGALRM_MASK;
- return;
- }
-
- block_signals();
-
- do_boot_timer_handler(sc);
- set_signals(enabled);
-}
-
void set_sigstack(void *sig_stack, int size)
{
stack_t stack = ((stack_t) { .ss_flags = 0,
panic("disabling signal stack failed, errno = %d\n", errno);
}
+void (*handlers[_NSIG])(int sig, struct sigcontext *sc);
+
+void handle_signal(int sig, struct sigcontext *sc)
+{
+ unsigned long pending = 0;
+
+ do {
+ int nested, bail;
+
+ /*
+ * pending comes back with one bit set for each
+ * interrupt that arrived while setting up the stack,
+ * plus a bit for this interrupt, plus the zero bit is
+ * set if this is a nested interrupt.
+ * If bail is true, then we interrupted another
+ * handler setting up the stack. In this case, we
+ * have to return, and the upper handler will deal
+ * with this interrupt.
+ */
+ bail = to_irq_stack(sig, &pending);
+ if(bail)
+ return;
+
+ nested = pending & 1;
+ pending &= ~1;
+
+ while((sig = ffs(pending)) != 0){
+ sig--;
+ pending &= ~(1 << sig);
+ (*handlers[sig])(sig, sc);
+ }
+
+ /* Again, pending comes back with a mask of signals
+ * that arrived while tearing down the stack. If this
+ * is non-zero, we just go back, set up the stack
+ * again, and handle the new interrupts.
+ */
+ if(!nested)
+ pending = from_irq_stack(nested);
+ } while(pending);
+}
+
+extern void hard_handler(int sig);
+
void set_handler(int sig, void (*handler)(int), int flags, ...)
{
struct sigaction action;
sigset_t sig_mask;
int mask;
- va_start(ap, flags);
- action.sa_handler = handler;
+ handlers[sig] = (void (*)(int, struct sigcontext *)) handler;
+ action.sa_handler = hard_handler;
+
sigemptyset(&action.sa_mask);
- while((mask = va_arg(ap, int)) != -1){
+
+ va_start(ap, flags);
+ while((mask = va_arg(ap, int)) != -1)
sigaddset(&action.sa_mask, mask);
- }
va_end(ap);
+
action.sa_flags = flags;
action.sa_restorer = NULL;
if(sigaction(sig, &action, NULL) < 0)
void block_signals(void)
{
signals_enabled = 0;
+ /* This must return with signals disabled, so this barrier
+ * ensures that writes are flushed out before the return.
+ * This might matter if gcc figures out how to inline this and
+ * decides to shuffle this code into the caller.
+ */
+ mb();
}
void unblock_signals(void)
*/
signals_enabled = 1;
+ /* Setting signals_enabled and reading pending must
+ * happen in this order.
+ */
+ mb();
+
save_pending = pending;
- if(save_pending == 0)
+ if(save_pending == 0){
+ /* This must return with signals enabled, so
+ * this barrier ensures that writes are
+ * flushed out before the return. This might
+ * matter if gcc figures out how to inline
+ * this (unlikely, given its size) and decides
+ * to shuffle this code into the caller.
+ */
+ mb();
return;
+ }
pending = 0;
return ret;
}
-
-void os_usr1_signal(int on)
-{
- change_sig(SIGUSR1, on);
-}
projects / linux-2.6-omap-h63xx.git / blobdiff