diff options
| author | Sarbojit Ganguly <ganguly.s@samsung.com> | 2015-10-09 12:10:02 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2015-10-09 16:22:54 +0100 |
| commit | e8973a889e69cb86cac08bec2863c878c0d27af9 (patch) | |
| tree | e38d278665d5998a1f4cc2df2eee8a5608440b32 /arch/arm/include/asm/cmpxchg.h | |
| parent | e1b8c05dccc7d3de8c49c92c41b2b5ac7d8275b2 (diff) | |
| download | linux-e8973a889e69cb86cac08bec2863c878c0d27af9.tar.bz2 | |
ARM: 8443/1: Adding support for atomic half word exchange
Since support for half-word atomic exchange was not there and Qspinlock
on ARM requires it, modified __xchg() to add support for that as well.
ARMv6 and lower does not support ldrex{b,h} so, added a guard code to
prevent build breaks.
Signed-off-by: Sarbojit Ganguly <ganguly.s@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/include/asm/cmpxchg.h')
| -rw-r--r-- | arch/arm/include/asm/cmpxchg.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/arch/arm/include/asm/cmpxchg.h b/arch/arm/include/asm/cmpxchg.h index 916a2744d5c6..97882f9bad12 100644 --- a/arch/arm/include/asm/cmpxchg.h +++ b/arch/arm/include/asm/cmpxchg.h @@ -39,6 +39,7 @@ static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size switch (size) { #if __LINUX_ARM_ARCH__ >= 6 +#ifndef CONFIG_CPU_V6 /* MIN ARCH >= V6K */ case 1: asm volatile("@ __xchg1\n" "1: ldrexb %0, [%3]\n" @@ -49,6 +50,17 @@ static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size : "r" (x), "r" (ptr) : "memory", "cc"); break; + case 2: + asm volatile("@ __xchg2\n" + "1: ldrexh %0, [%3]\n" + " strexh %1, %2, [%3]\n" + " teq %1, #0\n" + " bne 1b" + : "=&r" (ret), "=&r" (tmp) + : "r" (x), "r" (ptr) + : "memory", "cc"); + break; +#endif case 4: asm volatile("@ __xchg4\n" "1: ldrex %0, [%3]\n" |