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-rw-r--r--arch/um/os-Linux/signal.c28
1 files changed, 8 insertions, 20 deletions
diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c
index 7ff8f57b7150..62a66f38a913 100644
--- a/arch/um/os-Linux/signal.c
+++ b/arch/um/os-Linux/signal.c
@@ -15,6 +15,9 @@
#include "sysdep/sigcontext.h"
#include "user.h"
+/* Copied from linux/compiler-gcc.h since we can't include it directly */
+#define barrier() __asm__ __volatile__("": : :"memory")
+
/*
* 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
@@ -27,13 +30,8 @@
#define SIGVTALRM_BIT 1
#define SIGVTALRM_MASK (1 << SIGVTALRM_BIT)
-/*
- * 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;
+static int signals_enabled;
+static unsigned int pending;
void sig_handler(int sig, struct sigcontext *sc)
{
@@ -198,7 +196,7 @@ void block_signals(void)
* This might matter if gcc figures out how to inline this and
* decides to shuffle this code into the caller.
*/
- mb();
+ barrier();
}
void unblock_signals(void)
@@ -224,21 +222,11 @@ void unblock_signals(void)
* Setting signals_enabled and reading pending must
* happen in this order.
*/
- mb();
+ barrier();
save_pending = pending;
- 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();
+ if (save_pending == 0)
return;
- }
pending = 0;
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