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s390/percpu: make use of interlocked-access facility 1 instructions
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Optimize this_cpu_* functions for 64 bit by making use of new instructions
that came with the interlocked-access facility 1 (load-and-*) and the
general-instructions-extension facility (asi, agsi).
That way we get rid of the compare-and-swap loop in most cases.
Code size reduction (defconfig, -march=z196): 11,555 bytes.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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Heiko Carstens authored and Martin Schwidefsky committed Oct 24, 2013
1 parent 0702fbf commit f84cd97
Showing 1 changed file with 100 additions and 25 deletions.
125 changes: 100 additions & 25 deletions arch/s390/include/asm/percpu.h
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Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,11 @@
#define ARCH_NEEDS_WEAK_PER_CPU
#endif

#define arch_this_cpu_to_op(pcp, val, op) \
/*
* We use a compare-and-swap loop since that uses less cpu cycles than
* disabling and enabling interrupts like the generic variant would do.
*/
#define arch_this_cpu_to_op_simple(pcp, val, op) \
({ \
typedef typeof(pcp) pcp_op_T__; \
pcp_op_T__ old__, new__, prev__; \
Expand All @@ -38,30 +42,101 @@
new__; \
})

#define this_cpu_add_1(pcp, val) arch_this_cpu_to_op(pcp, val, +)
#define this_cpu_add_2(pcp, val) arch_this_cpu_to_op(pcp, val, +)
#define this_cpu_add_4(pcp, val) arch_this_cpu_to_op(pcp, val, +)
#define this_cpu_add_8(pcp, val) arch_this_cpu_to_op(pcp, val, +)

#define this_cpu_add_return_1(pcp, val) arch_this_cpu_to_op(pcp, val, +)
#define this_cpu_add_return_2(pcp, val) arch_this_cpu_to_op(pcp, val, +)
#define this_cpu_add_return_4(pcp, val) arch_this_cpu_to_op(pcp, val, +)
#define this_cpu_add_return_8(pcp, val) arch_this_cpu_to_op(pcp, val, +)

#define this_cpu_and_1(pcp, val) arch_this_cpu_to_op(pcp, val, &)
#define this_cpu_and_2(pcp, val) arch_this_cpu_to_op(pcp, val, &)
#define this_cpu_and_4(pcp, val) arch_this_cpu_to_op(pcp, val, &)
#define this_cpu_and_8(pcp, val) arch_this_cpu_to_op(pcp, val, &)

#define this_cpu_or_1(pcp, val) arch_this_cpu_to_op(pcp, val, |)
#define this_cpu_or_2(pcp, val) arch_this_cpu_to_op(pcp, val, |)
#define this_cpu_or_4(pcp, val) arch_this_cpu_to_op(pcp, val, |)
#define this_cpu_or_8(pcp, val) arch_this_cpu_to_op(pcp, val, |)

#define this_cpu_xor_1(pcp, val) arch_this_cpu_to_op(pcp, val, ^)
#define this_cpu_xor_2(pcp, val) arch_this_cpu_to_op(pcp, val, ^)
#define this_cpu_xor_4(pcp, val) arch_this_cpu_to_op(pcp, val, ^)
#define this_cpu_xor_8(pcp, val) arch_this_cpu_to_op(pcp, val, ^)
#define this_cpu_add_1(pcp, val) arch_this_cpu_to_op_simple(pcp, val, +)
#define this_cpu_add_2(pcp, val) arch_this_cpu_to_op_simple(pcp, val, +)
#define this_cpu_add_return_1(pcp, val) arch_this_cpu_to_op_simple(pcp, val, +)
#define this_cpu_add_return_2(pcp, val) arch_this_cpu_to_op_simple(pcp, val, +)
#define this_cpu_and_1(pcp, val) arch_this_cpu_to_op_simple(pcp, val, &)
#define this_cpu_and_2(pcp, val) arch_this_cpu_to_op_simple(pcp, val, &)
#define this_cpu_or_1(pcp, val) arch_this_cpu_to_op_simple(pcp, val, |)
#define this_cpu_or_2(pcp, val) arch_this_cpu_to_op_simple(pcp, val, |)
#define this_cpu_xor_1(pcp, val) arch_this_cpu_to_op_simple(pcp, val, ^)
#define this_cpu_xor_2(pcp, val) arch_this_cpu_to_op_simple(pcp, val, ^)

#ifndef CONFIG_HAVE_MARCH_Z196_FEATURES

#define this_cpu_add_4(pcp, val) arch_this_cpu_to_op_simple(pcp, val, +)
#define this_cpu_add_8(pcp, val) arch_this_cpu_to_op_simple(pcp, val, +)
#define this_cpu_add_return_4(pcp, val) arch_this_cpu_to_op_simple(pcp, val, +)
#define this_cpu_add_return_8(pcp, val) arch_this_cpu_to_op_simple(pcp, val, +)
#define this_cpu_and_4(pcp, val) arch_this_cpu_to_op_simple(pcp, val, &)
#define this_cpu_and_8(pcp, val) arch_this_cpu_to_op_simple(pcp, val, &)
#define this_cpu_or_4(pcp, val) arch_this_cpu_to_op_simple(pcp, val, |)
#define this_cpu_or_8(pcp, val) arch_this_cpu_to_op_simple(pcp, val, |)
#define this_cpu_xor_4(pcp, val) arch_this_cpu_to_op_simple(pcp, val, ^)
#define this_cpu_xor_8(pcp, val) arch_this_cpu_to_op_simple(pcp, val, ^)

#else /* CONFIG_HAVE_MARCH_Z196_FEATURES */

#define arch_this_cpu_add(pcp, val, op1, op2, szcast) \
{ \
typedef typeof(pcp) pcp_op_T__; \
pcp_op_T__ val__ = (val); \
pcp_op_T__ old__, *ptr__; \
preempt_disable(); \
ptr__ = __this_cpu_ptr(&(pcp)); \
if (__builtin_constant_p(val__) && \
((szcast)val__ > -129) && ((szcast)val__ < 128)) { \
asm volatile( \
op2 " %[ptr__],%[val__]\n" \
: [ptr__] "+Q" (*ptr__) \
: [val__] "i" ((szcast)val__) \
: "cc"); \
} else { \
asm volatile( \
op1 " %[old__],%[val__],%[ptr__]\n" \
: [old__] "=d" (old__), [ptr__] "+Q" (*ptr__) \
: [val__] "d" (val__) \
: "cc"); \
} \
preempt_enable(); \
}

#define this_cpu_add_4(pcp, val) arch_this_cpu_add(pcp, val, "laa", "asi", int)
#define this_cpu_add_8(pcp, val) arch_this_cpu_add(pcp, val, "laag", "agsi", long)

#define arch_this_cpu_add_return(pcp, val, op) \
({ \
typedef typeof(pcp) pcp_op_T__; \
pcp_op_T__ val__ = (val); \
pcp_op_T__ old__, *ptr__; \
preempt_disable(); \
ptr__ = __this_cpu_ptr(&(pcp)); \
asm volatile( \
op " %[old__],%[val__],%[ptr__]\n" \
: [old__] "=d" (old__), [ptr__] "+Q" (*ptr__) \
: [val__] "d" (val__) \
: "cc"); \
preempt_enable(); \
old__ + val__; \
})

#define this_cpu_add_return_4(pcp, val) arch_this_cpu_add_return(pcp, val, "laa")
#define this_cpu_add_return_8(pcp, val) arch_this_cpu_add_return(pcp, val, "laag")

#define arch_this_cpu_to_op(pcp, val, op) \
{ \
typedef typeof(pcp) pcp_op_T__; \
pcp_op_T__ val__ = (val); \
pcp_op_T__ old__, *ptr__; \
preempt_disable(); \
ptr__ = __this_cpu_ptr(&(pcp)); \
asm volatile( \
op " %[old__],%[val__],%[ptr__]\n" \
: [old__] "=d" (old__), [ptr__] "+Q" (*ptr__) \
: [val__] "d" (val__) \
: "cc"); \
preempt_enable(); \
}

#define this_cpu_and_4(pcp, val) arch_this_cpu_to_op(pcp, val, "lan")
#define this_cpu_and_8(pcp, val) arch_this_cpu_to_op(pcp, val, "lang")
#define this_cpu_or_4(pcp, val) arch_this_cpu_to_op(pcp, val, "lao")
#define this_cpu_or_8(pcp, val) arch_this_cpu_to_op(pcp, val, "laog")
#define this_cpu_xor_4(pcp, val) arch_this_cpu_to_op(pcp, val, "lax")
#define this_cpu_xor_8(pcp, val) arch_this_cpu_to_op(pcp, val, "laxg")

#endif /* CONFIG_HAVE_MARCH_Z196_FEATURES */

#define arch_this_cpu_cmpxchg(pcp, oval, nval) \
({ \
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