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s390/atomic_ops: Improve __atomic_set() for small values

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Use mvhi/mvghi for small constant values within the __atomic_set()
inline assemblies. This avoids loading the specified value into a
register.

The size of the kernel image is reduced by ~1.2kb.

Reviewed-by: Juergen Christ <jchrist@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Heiko Carstens 2024-07-01 17:04:57 +02:00 committed by Vasily Gorbik
parent f2ed8367bf
commit ee19370c92
1 changed files with 20 additions and 6 deletions
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26
arch/s390/include/asm/atomic_ops.h
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@ -8,6 +8,8 @@
#ifndef __ARCH_S390_ATOMIC_OPS__
#define __ARCH_S390_ATOMIC_OPS__
#include <linux/limits.h>
static __always_inline int __atomic_read(const atomic_t *v)
{
int c;
@ -20,9 +22,15 @@ static __always_inline int __atomic_read(const atomic_t *v)
static __always_inline void __atomic_set(atomic_t *v, int i)
{
asm volatile(
" st %[i],%[counter]\n"
: [counter] "=R" (v->counter) : [i] "d" (i));
if (__builtin_constant_p(i) && i >= S16_MIN && i <= S16_MAX) {
asm volatile(
" mvhi %[counter], %[i]\n"
: [counter] "=Q" (v->counter) : [i] "K" (i));
} else {
asm volatile(
" st %[i],%[counter]\n"
: [counter] "=R" (v->counter) : [i] "d" (i));
}
}
static __always_inline s64 __atomic64_read(const atomic64_t *v)
@ -37,9 +45,15 @@ static __always_inline s64 __atomic64_read(const atomic64_t *v)
static __always_inline void __atomic64_set(atomic64_t *v, s64 i)
{
asm volatile(
" stg %[i],%[counter]\n"
: [counter] "=RT" (v->counter) : [i] "d" (i));
if (__builtin_constant_p(i) && i >= S16_MIN && i <= S16_MAX) {
asm volatile(
" mvghi %[counter], %[i]\n"
: [counter] "=Q" (v->counter) : [i] "K" (i));
} else {
asm volatile(
" stg %[i],%[counter]\n"
: [counter] "=RT" (v->counter) : [i] "d" (i));
}
}
#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES