From b791d1193af9772040e592d5aa161790f800b762 Mon Sep 17 00:00:00 2001 From: David Daney Date: Mon, 13 Jul 2009 11:15:19 -0700 Subject: 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 Signed-off-by: Ralf Baechle --- arch/mips/include/asm/cpu-features.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'arch/mips/include/asm/cpu-features.h') diff --git a/arch/mips/include/asm/cpu-features.h b/arch/mips/include/asm/cpu-features.h index 8ab1d12ba7f..1f4df647c38 100644 --- a/arch/mips/include/asm/cpu-features.h +++ b/arch/mips/include/asm/cpu-features.h @@ -80,6 +80,9 @@ #ifndef cpu_has_llsc #define cpu_has_llsc (cpu_data[0].options & MIPS_CPU_LLSC) #endif +#ifndef kernel_uses_llsc +#define kernel_uses_llsc cpu_has_llsc +#endif #ifndef cpu_has_mips16 #define cpu_has_mips16 (cpu_data[0].ases & MIPS_ASE_MIPS16) #endif -- cgit v1.2.3