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authorDale Rahn <drahn@cvs.openbsd.org>2007-03-17 23:42:07 +0000
committerDale Rahn <drahn@cvs.openbsd.org>2007-03-17 23:42:07 +0000
commitd142a65d62ed395d327a6f9a5558c75b1e9a9c40 (patch)
treec00424bdb2e23b59ea7cec400cfde027ee210473 /sys/arch/arm
parent66842cdc24fa5ece692a06fc8131157de196905b (diff)
For arm pre-v6 (ie all supported machines) it is necessary to disable
interrupts to be able to have an atomic update of a variable without a mutex.
Diffstat (limited to 'sys/arch/arm')
-rw-r--r--sys/arch/arm/include/atomic.h13
1 files changed, 12 insertions, 1 deletions
diff --git a/sys/arch/arm/include/atomic.h b/sys/arch/arm/include/atomic.h
index a3ac330fc85..280a48d59ca 100644
--- a/sys/arch/arm/include/atomic.h
+++ b/sys/arch/arm/include/atomic.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: atomic.h,v 1.4 2007/02/19 17:18:42 deraadt Exp $ */
+/* $OpenBSD: atomic.h,v 1.5 2007/03/17 23:42:06 drahn Exp $ */
/* Public Domain */
@@ -7,16 +7,27 @@
#if defined(_KERNEL)
+/*
+ * on pre-v6 arm processors, it is necessary to disable interrupts if
+ * in the kernel and atomic updates are necessary without full mutexes
+ */
+
static __inline void
atomic_setbits_int(__volatile unsigned int *uip, unsigned int v)
{
+ int oldirqstate;
+ oldirqstate = disable_interrupts(I32_bit|F32_bit);
*uip |= v;
+ restore_interrupts(oldirqstate);
}
static __inline void
atomic_clearbits_int(__volatile unsigned int *uip, unsigned int v)
{
+ int oldirqstate;
+ oldirqstate = disable_interrupts(I32_bit|F32_bit);
*uip &= ~v;
+ restore_interrupts(oldirqstate);
}
#endif /* defined(_KERNEL) */