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authorHeiko Carstens <heiko.carstens@de.ibm.com>2011-05-23 10:24:32 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2011-05-23 10:24:29 +0200
commit4c2241fd42298007d7c3a92318806a4a9490a93c (patch)
tree13e9af56e8f0badae7c8a238901e542163c115e2 /arch/s390/include/asm/percpu.h
parentadd7490c273650c3aa8012f3e082aa64af86f17c (diff)
[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 <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/include/asm/percpu.h')
-rw-r--r--arch/s390/include/asm/percpu.h68
1 files changed, 68 insertions, 0 deletions
diff --git a/arch/s390/include/asm/percpu.h b/arch/s390/include/asm/percpu.h
index f7ad8719d02..5325c89a584 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 <linux/preempt.h>
+#include <asm/cmpxchg.h>
+
/*
* 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 <asm-generic/percpu.h>
#endif /* __ARCH_S390_PERCPU__ */