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authorDavid Daney <ddaney@caviumnetworks.com>2009-07-13 11:15:19 -0700
committerRalf Baechle <ralf@linux-mips.org>2009-09-17 20:07:50 +0200
commitb791d1193af9772040e592d5aa161790f800b762 (patch)
tree6adad3d9cdf278a3a1a3418ae75a2864d0cc7f39 /arch/mips/include/asm/system.h
parentf7ade3c168e4f437c11f57be012992bbb0e3075c (diff)
MIPS: Allow kernel use of LL/SC to be separate from the presence of LL/SC.
On some CPUs, it is more efficient to disable and enable interrupts in the kernel rather than use ll/sc for atomic operations. But if we were to set cpu_has_llsc to false, we would break the userspace futex interface (in asm/futex.h). We separate the two concepts, with a new predicate kernel_uses_llsc, that lets us disable the kernel's use of ll/sc while still allowing the futex code to use it. Also there were a couple of cases in bitops.h where we were using ll/sc unconditionally even if cpu_has_llsc were false. Signed-off-by: David Daney <ddaney@caviumnetworks.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/include/asm/system.h')
-rw-r--r--arch/mips/include/asm/system.h8
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/mips/include/asm/system.h b/arch/mips/include/asm/system.h
index cc7262ff076..fcf5f98d90c 100644
--- a/arch/mips/include/asm/system.h
+++ b/arch/mips/include/asm/system.h
@@ -94,7 +94,7 @@ static inline unsigned long __xchg_u32(volatile int * m, unsigned int val)
{
__u32 retval;
- if (cpu_has_llsc && R10000_LLSC_WAR) {
+ if (kernel_uses_llsc && R10000_LLSC_WAR) {
unsigned long dummy;
__asm__ __volatile__(
@@ -109,7 +109,7 @@ static inline unsigned long __xchg_u32(volatile int * m, unsigned int val)
: "=&r" (retval), "=m" (*m), "=&r" (dummy)
: "R" (*m), "Jr" (val)
: "memory");
- } else if (cpu_has_llsc) {
+ } else if (kernel_uses_llsc) {
unsigned long dummy;
__asm__ __volatile__(
@@ -146,7 +146,7 @@ static inline __u64 __xchg_u64(volatile __u64 * m, __u64 val)
{
__u64 retval;
- if (cpu_has_llsc && R10000_LLSC_WAR) {
+ if (kernel_uses_llsc && R10000_LLSC_WAR) {
unsigned long dummy;
__asm__ __volatile__(
@@ -159,7 +159,7 @@ static inline __u64 __xchg_u64(volatile __u64 * m, __u64 val)
: "=&r" (retval), "=m" (*m), "=&r" (dummy)
: "R" (*m), "Jr" (val)
: "memory");
- } else if (cpu_has_llsc) {
+ } else if (kernel_uses_llsc) {
unsigned long dummy;
__asm__ __volatile__(