Commit a7d06833 authored Nov 16, 2005 by Nicolas Pitre Committed by Russell King Nov 16, 2005

[ARM] 3165/1: fix atomic_cmpxchg() implementation for ARMv6+



Patch from Nicolas Pitre

If 'old' and 'oldval' are different then 'res' never gets set.  In that
case, if ever %0 happened to contain anything but zero (rather likely)
then the code will loop forever (or until another CPU just come along
and change the atomic value to match 'old' which is rather unlikely).

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

parent 224b5be6

include/asm-arm/atomic.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -87,6 +87,7 @@ static inline int atomic_cmpxchg(atomic_t *ptr, int old, int new)
		do {
		__asm__ __volatile__("@ atomic_cmpxchg\n"
		"ldrex %1, [%2]\n"
		"mov %0, #0\n"
		"teq %1, %3\n"
		"strexeq %0, %4, [%2]\n"
		: "=&r" (res), "=&r" (oldval)