diff options
| author | David Daney <ddaney@caviumnetworks.com> | 2009-07-13 14:15:19 -0400 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2009-09-17 14:07:50 -0400 |
| commit | b791d1193af9772040e592d5aa161790f800b762 (patch) | |
| tree | 6adad3d9cdf278a3a1a3418ae75a2864d0cc7f39 /arch/mips/include/asm/cmpxchg.h | |
| parent | f7ade3c168e4f437c11f57be012992bbb0e3075c (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/cmpxchg.h')
| -rw-r--r-- | arch/mips/include/asm/cmpxchg.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/mips/include/asm/cmpxchg.h b/arch/mips/include/asm/cmpxchg.h index 4a812c3ceb90..815a438a268d 100644 --- a/arch/mips/include/asm/cmpxchg.h +++ b/arch/mips/include/asm/cmpxchg.h | |||
| @@ -16,7 +16,7 @@ | |||
| 16 | ({ \ | 16 | ({ \ |
| 17 | __typeof(*(m)) __ret; \ | 17 | __typeof(*(m)) __ret; \ |
| 18 | \ | 18 | \ |
| 19 | if (cpu_has_llsc && R10000_LLSC_WAR) { \ | 19 | if (kernel_uses_llsc && R10000_LLSC_WAR) { \ |
| 20 | __asm__ __volatile__( \ | 20 | __asm__ __volatile__( \ |
| 21 | " .set push \n" \ | 21 | " .set push \n" \ |
| 22 | " .set noat \n" \ | 22 | " .set noat \n" \ |
| @@ -33,7 +33,7 @@ | |||
| 33 | : "=&r" (__ret), "=R" (*m) \ | 33 | : "=&r" (__ret), "=R" (*m) \ |
| 34 | : "R" (*m), "Jr" (old), "Jr" (new) \ | 34 | : "R" (*m), "Jr" (old), "Jr" (new) \ |
| 35 | : "memory"); \ | 35 | : "memory"); \ |
| 36 | } else if (cpu_has_llsc) { \ | 36 | } else if (kernel_uses_llsc) { \ |
| 37 | __asm__ __volatile__( \ | 37 | __asm__ __volatile__( \ |
| 38 | " .set push \n" \ | 38 | " .set push \n" \ |
| 39 | " .set noat \n" \ | 39 | " .set noat \n" \ |