From 4c2241fd42298007d7c3a92318806a4a9490a93c Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Mon, 23 May 2011 10:24:32 +0200 Subject: [PATCH] [S390] percpu: implement arch specific irqsafe_cpu_ops Implement arch specific irqsafe_cpu ops. The arch specific ops do not disable/enable interrupts since that is an expensive operation. Instead we disable preemption and perform a compare and swap loop. Since on server distros (the ones we care about) preemption is disabled the preempt_disable()/preempt_enable() pair is a nop. In the end this code should be faster than the generic one. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/include/asm/cmpxchg.h | 1 - arch/s390/include/asm/percpu.h | 68 +++++++++++++++++++++++++++++++++ 2 files changed, 68 insertions(+), 1 deletion(-) diff --git a/arch/s390/include/asm/cmpxchg.h b/arch/s390/include/asm/cmpxchg.h index 7488e52efa97..81d7908416cf 100644 --- a/arch/s390/include/asm/cmpxchg.h +++ b/arch/s390/include/asm/cmpxchg.h @@ -167,7 +167,6 @@ static inline unsigned long __cmpxchg(void *ptr, unsigned long old, #ifdef CONFIG_64BIT #define cmpxchg64(ptr, o, n) \ ({ \ - BUILD_BUG_ON(sizeof(*(ptr)) != 8); \ cmpxchg((ptr), (o), (n)); \ }) #else /* CONFIG_64BIT */ diff --git a/arch/s390/include/asm/percpu.h b/arch/s390/include/asm/percpu.h index f7ad8719d02d..5325c89a5843 100644 --- a/arch/s390/include/asm/percpu.h +++ b/arch/s390/include/asm/percpu.h @@ -1,6 +1,9 @@ #ifndef __ARCH_S390_PERCPU__ #define __ARCH_S390_PERCPU__ +#include +#include + /* * s390 uses its own implementation for per cpu data, the offset of * the cpu local data area is cached in the cpu's lowcore memory. @@ -16,6 +19,71 @@ #define ARCH_NEEDS_WEAK_PER_CPU #endif +#define arch_irqsafe_cpu_to_op(pcp, val, op) \ +do { \ + typedef typeof(pcp) pcp_op_T__; \ + pcp_op_T__ old__, new__, prev__; \ + pcp_op_T__ *ptr__; \ + preempt_disable(); \ + ptr__ = __this_cpu_ptr(&(pcp)); \ + prev__ = *ptr__; \ + do { \ + old__ = prev__; \ + new__ = old__ op (val); \ + switch (sizeof(*ptr__)) { \ + case 8: \ + prev__ = cmpxchg64(ptr__, old__, new__); \ + break; \ + default: \ + prev__ = cmpxchg(ptr__, old__, new__); \ + } \ + } while (prev__ != old__); \ + preempt_enable(); \ +} while (0) + +#define irqsafe_cpu_add_1(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, +) +#define irqsafe_cpu_add_2(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, +) +#define irqsafe_cpu_add_4(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, +) +#define irqsafe_cpu_add_8(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, +) + +#define irqsafe_cpu_and_1(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, &) +#define irqsafe_cpu_and_2(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, &) +#define irqsafe_cpu_and_4(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, &) +#define irqsafe_cpu_and_8(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, &) + +#define irqsafe_cpu_or_1(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, |) +#define irqsafe_cpu_or_2(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, |) +#define irqsafe_cpu_or_4(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, |) +#define irqsafe_cpu_or_8(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, |) + +#define irqsafe_cpu_xor_1(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, ^) +#define irqsafe_cpu_xor_2(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, ^) +#define irqsafe_cpu_xor_4(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, ^) +#define irqsafe_cpu_xor_8(pcp, val) arch_irqsafe_cpu_to_op(pcp, val, ^) + +#define arch_irqsafe_cpu_cmpxchg(pcp, oval, nval) \ +({ \ + typedef typeof(pcp) pcp_op_T__; \ + pcp_op_T__ ret__; \ + pcp_op_T__ *ptr__; \ + preempt_disable(); \ + ptr__ = __this_cpu_ptr(&(pcp)); \ + switch (sizeof(*ptr__)) { \ + case 8: \ + ret__ = cmpxchg64(ptr__, oval, nval); \ + break; \ + default: \ + ret__ = cmpxchg(ptr__, oval, nval); \ + } \ + preempt_enable(); \ + ret__; \ +}) + +#define irqsafe_cpu_cmpxchg_1(pcp, oval, nval) arch_irqsafe_cpu_cmpxchg(pcp, oval, nval) +#define irqsafe_cpu_cmpxchg_2(pcp, oval, nval) arch_irqsafe_cpu_cmpxchg(pcp, oval, nval) +#define irqsafe_cpu_cmpxchg_4(pcp, oval, nval) arch_irqsafe_cpu_cmpxchg(pcp, oval, nval) +#define irqsafe_cpu_cmpxchg_8(pcp, oval, nval) arch_irqsafe_cpu_cmpxchg(pcp, oval, nval) + #include #endif /* __ARCH_S390_PERCPU__ */ -- 2.20.1