]> pilppa.org Git - linux-2.6-omap-h63xx.git/blobdiff - arch/um/os-Linux/signal.c
uml: fix !NO_HZ busy-loop
[linux-2.6-omap-h63xx.git] / arch / um / os-Linux / signal.c
index b98f7ea2d2f6562ce894e4a4fe6f57b003af7768..e9800b0b5689b6abc750606ab886826709964e56 100644 (file)
@@ -1,26 +1,21 @@
 /*
  * Copyright (C) 2004 PathScale, Inc
+ * Copyright (C) 2004 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  * Licensed under the GPL
  */
 
-#include <signal.h>
-#include <stdio.h>
-#include <unistd.h>
 #include <stdlib.h>
-#include <errno.h>
 #include <stdarg.h>
-#include <string.h>
-#include <sys/mman.h>
-#include "user.h"
-#include "signal_kern.h"
-#include "sysdep/sigcontext.h"
-#include "sysdep/barrier.h"
-#include "sigcontext.h"
-#include "mode.h"
+#include <errno.h>
+#include <signal.h>
+#include <strings.h>
 #include "os.h"
+#include "sysdep/barrier.h"
+#include "sysdep/sigcontext.h"
+#include "user.h"
 
-/* These are the asynchronous signals.  SIGVTALRM and SIGARLM are handled
- * together under SIGVTALRM_BIT.  SIGPROF is excluded because we want to
+/*
+ * These are the asynchronous signals.  SIGPROF is excluded because we want to
  * be able to profile all of UML, not just the non-critical sections.  If
  * profiling is not thread-safe, then that is not my problem.  We can disable
  * profiling when SMP is enabled in that case.
 #define SIGVTALRM_BIT 1
 #define SIGVTALRM_MASK (1 << SIGVTALRM_BIT)
 
-#define SIGALRM_BIT 2
-#define SIGALRM_MASK (1 << SIGALRM_BIT)
-
-/* These are used by both the signal handlers and
+/*
+ * 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.
  */
@@ -46,34 +39,27 @@ void sig_handler(int sig, struct sigcontext *sc)
        int enabled;
 
        enabled = signals_enabled;
-       if(!enabled && (sig == SIGIO)){
+       if (!enabled && (sig == SIGIO)) {
                pending |= SIGIO_MASK;
                return;
        }
 
        block_signals();
 
-       CHOOSE_MODE_PROC(sig_handler_common_tt, sig_handler_common_skas,
-                        sig, sc);
+       sig_handler_common_skas(sig, sc);
 
        set_signals(enabled);
 }
 
-static void real_alarm_handler(int sig, struct sigcontext *sc)
+static void real_alarm_handler(struct sigcontext *sc)
 {
-       union uml_pt_regs regs;
+       struct uml_pt_regs regs;
 
-       if(sig == SIGALRM)
-               switch_timers(0);
-
-       if(sc != NULL)
+       if (sc != NULL)
                copy_sc(&regs, sc);
-       regs.skas.is_user = 0;
+       regs.is_user = 0;
        unblock_signals();
-       timer_handler(sig, &regs);
-
-       if(sig == SIGALRM)
-               switch_timers(1);
+       timer_handler(SIGVTALRM, &regs);
 }
 
 void alarm_handler(int sig, struct sigcontext *sc)
@@ -81,27 +67,30 @@ void alarm_handler(int sig, struct sigcontext *sc)
        int enabled;
 
        enabled = signals_enabled;
-       if(!signals_enabled){
-               if(sig == SIGVTALRM)
-                       pending |= SIGVTALRM_MASK;
-               else pending |= SIGALRM_MASK;
-
+       if (!signals_enabled) {
+               pending |= SIGVTALRM_MASK;
                return;
        }
 
        block_signals();
 
-       real_alarm_handler(sig, sc);
+       real_alarm_handler(sc);
        set_signals(enabled);
 }
 
+void timer_init(void)
+{
+       set_handler(SIGVTALRM, (__sighandler_t) alarm_handler,
+                   SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGWINCH, -1);
+}
+
 void set_sigstack(void *sig_stack, int size)
 {
        stack_t stack = ((stack_t) { .ss_flags  = 0,
                                     .ss_sp     = (__ptr_t) sig_stack,
                                     .ss_size   = size - sizeof(void *) });
 
-       if(sigaltstack(&stack, NULL) != 0)
+       if (sigaltstack(&stack, NULL) != 0)
                panic("enabling signal stack failed, errno = %d\n", errno);
 }
 
@@ -111,7 +100,7 @@ void remove_sigstack(void)
                                     .ss_sp     = NULL,
                                     .ss_size   = 0 });
 
-       if(sigaltstack(&stack, NULL) != 0)
+       if (sigaltstack(&stack, NULL) != 0)
                panic("disabling signal stack failed, errno = %d\n", errno);
 }
 
@@ -135,26 +124,27 @@ void handle_signal(int sig, struct sigcontext *sc)
                 * with this interrupt.
                 */
                bail = to_irq_stack(&pending);
-               if(bail)
+               if (bail)
                        return;
 
                nested = pending & 1;
                pending &= ~1;
 
-               while((sig = ffs(pending)) != 0){
+               while ((sig = ffs(pending)) != 0){
                        sig--;
                        pending &= ~(1 << sig);
                        (*handlers[sig])(sig, sc);
                }
 
-               /* Again, pending comes back with a mask of signals
+               /*
+                * 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)
+               if (!nested)
                        pending = from_irq_stack(nested);
-       } while(pending);
+       } while (pending);
 }
 
 extern void hard_handler(int sig);
@@ -172,18 +162,18 @@ void set_handler(int sig, void (*handler)(int), int flags, ...)
        sigemptyset(&action.sa_mask);
 
        va_start(ap, flags);
-       while((mask = va_arg(ap, int)) != -1)
+       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)
+       if (sigaction(sig, &action, NULL) < 0)
                panic("sigaction failed - errno = %d\n", errno);
 
        sigemptyset(&sig_mask);
        sigaddset(&sig_mask, sig);
-       if(sigprocmask(SIG_UNBLOCK, &sig_mask, NULL) < 0)
+       if (sigprocmask(SIG_UNBLOCK, &sig_mask, NULL) < 0)
                panic("sigprocmask failed - errno = %d\n", errno);
 }
 
@@ -194,13 +184,14 @@ int change_sig(int signal, int on)
        sigemptyset(&sigset);
        sigaddset(&sigset, signal);
        sigprocmask(on ? SIG_UNBLOCK : SIG_BLOCK, &sigset, &old);
-       return(!sigismember(&old, signal));
+       return !sigismember(&old, signal);
 }
 
 void block_signals(void)
 {
        signals_enabled = 0;
-       /* This must return with signals disabled, so this barrier
+       /*
+        * 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.
@@ -212,27 +203,31 @@ void unblock_signals(void)
 {
        int save_pending;
 
-       if(signals_enabled == 1)
+       if (signals_enabled == 1)
                return;
 
-       /* We loop because the IRQ handler returns with interrupts off.  So,
+       /*
+        * We loop because the IRQ handler returns with interrupts off.  So,
         * interrupts may have arrived and we need to re-enable them and
         * recheck pending.
         */
-       while(1){
-               /* Save and reset save_pending after enabling signals.  This
+       while(1) {
+               /*
+                * Save and reset save_pending after enabling signals.  This
                 * way, pending won't be changed while we're reading it.
                 */
                signals_enabled = 1;
 
-               /* Setting signals_enabled and reading pending must
+               /*
+                * Setting signals_enabled and reading pending must
                 * happen in this order.
                 */
                mb();
 
                save_pending = pending;
-               if(save_pending == 0){
-                       /* This must return with signals enabled, so
+               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
@@ -245,26 +240,24 @@ void unblock_signals(void)
 
                pending = 0;
 
-               /* We have pending interrupts, so disable signals, as the
+               /*
+                * We have pending interrupts, so disable signals, as the
                 * handlers expect them off when they are called.  They will
                 * be enabled again above.
                 */
 
                signals_enabled = 0;
 
-               /* Deal with SIGIO first because the alarm handler might
+               /*
+                * Deal with SIGIO first because the alarm handler might
                 * schedule, leaving the pending SIGIO stranded until we come
                 * back here.
                 */
-               if(save_pending & SIGIO_MASK)
-                       CHOOSE_MODE_PROC(sig_handler_common_tt,
-                                        sig_handler_common_skas, SIGIO, NULL);
-
-               if(save_pending & SIGALRM_MASK)
-                       real_alarm_handler(SIGALRM, NULL);
+               if (save_pending & SIGIO_MASK)
+                       sig_handler_common_skas(SIGIO, NULL);
 
-               if(save_pending & SIGVTALRM_MASK)
-                       real_alarm_handler(SIGVTALRM, NULL);
+               if (save_pending & SIGVTALRM_MASK)
+                       real_alarm_handler(NULL);
        }
 }
 
@@ -276,11 +269,11 @@ int get_signals(void)
 int set_signals(int enable)
 {
        int ret;
-       if(signals_enabled == enable)
+       if (signals_enabled == enable)
                return enable;
 
        ret = signals_enabled;
-       if(enable)
+       if (enable)
                unblock_signals();
        else block_signals();