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authorWill Deacon <will.deacon@arm.com>2018-09-13 15:30:45 +0300
committerWill Deacon <will.deacon@arm.com>2018-12-07 20:27:55 +0300
commit5ef3fe4cecdf82fdd71ce78988403963d01444d4 (patch)
tree937f28f9e3beea1a63e0d21c4c95bf604af3ade2 /arch/arm64/include/asm/atomic_lse.h
parent396244692232fcf0881cb6ba2404be2906f47681 (diff)
downloadlinux-5ef3fe4cecdf82fdd71ce78988403963d01444d4.tar.xz
arm64: Avoid redundant type conversions in xchg() and cmpxchg()
Our atomic instructions (either LSE atomics of LDXR/STXR sequences) natively support byte, half-word, word and double-word memory accesses so there is no need to mask the data register prior to being stored. Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/atomic_lse.h')
-rw-r--r--arch/arm64/include/asm/atomic_lse.h46
1 files changed, 23 insertions, 23 deletions
diff --git a/arch/arm64/include/asm/atomic_lse.h b/arch/arm64/include/asm/atomic_lse.h
index f9b0b09153e0..4d6f917b654e 100644
--- a/arch/arm64/include/asm/atomic_lse.h
+++ b/arch/arm64/include/asm/atomic_lse.h
@@ -446,22 +446,22 @@ static inline long atomic64_dec_if_positive(atomic64_t *v)
#define __LL_SC_CMPXCHG(op) __LL_SC_CALL(__cmpxchg_case_##op)
-#define __CMPXCHG_CASE(w, sz, name, mb, cl...) \
-static inline unsigned long __cmpxchg_case_##name(volatile void *ptr, \
- unsigned long old, \
- unsigned long new) \
+#define __CMPXCHG_CASE(w, sfx, name, sz, mb, cl...) \
+static inline u##sz __cmpxchg_case_##name##sz(volatile void *ptr, \
+ unsigned long old, \
+ u##sz new) \
{ \
register unsigned long x0 asm ("x0") = (unsigned long)ptr; \
register unsigned long x1 asm ("x1") = old; \
- register unsigned long x2 asm ("x2") = new; \
+ register u##sz x2 asm ("x2") = new; \
\
asm volatile(ARM64_LSE_ATOMIC_INSN( \
/* LL/SC */ \
- __LL_SC_CMPXCHG(name) \
+ __LL_SC_CMPXCHG(name##sz) \
__nops(2), \
/* LSE atomics */ \
" mov " #w "30, %" #w "[old]\n" \
- " cas" #mb #sz "\t" #w "30, %" #w "[new], %[v]\n" \
+ " cas" #mb #sfx "\t" #w "30, %" #w "[new], %[v]\n" \
" mov %" #w "[ret], " #w "30") \
: [ret] "+r" (x0), [v] "+Q" (*(unsigned long *)ptr) \
: [old] "r" (x1), [new] "r" (x2) \
@@ -470,22 +470,22 @@ static inline unsigned long __cmpxchg_case_##name(volatile void *ptr, \
return x0; \
}
-__CMPXCHG_CASE(w, b, 1, )
-__CMPXCHG_CASE(w, h, 2, )
-__CMPXCHG_CASE(w, , 4, )
-__CMPXCHG_CASE(x, , 8, )
-__CMPXCHG_CASE(w, b, acq_1, a, "memory")
-__CMPXCHG_CASE(w, h, acq_2, a, "memory")
-__CMPXCHG_CASE(w, , acq_4, a, "memory")
-__CMPXCHG_CASE(x, , acq_8, a, "memory")
-__CMPXCHG_CASE(w, b, rel_1, l, "memory")
-__CMPXCHG_CASE(w, h, rel_2, l, "memory")
-__CMPXCHG_CASE(w, , rel_4, l, "memory")
-__CMPXCHG_CASE(x, , rel_8, l, "memory")
-__CMPXCHG_CASE(w, b, mb_1, al, "memory")
-__CMPXCHG_CASE(w, h, mb_2, al, "memory")
-__CMPXCHG_CASE(w, , mb_4, al, "memory")
-__CMPXCHG_CASE(x, , mb_8, al, "memory")
+__CMPXCHG_CASE(w, b, , 8, )
+__CMPXCHG_CASE(w, h, , 16, )
+__CMPXCHG_CASE(w, , , 32, )
+__CMPXCHG_CASE(x, , , 64, )
+__CMPXCHG_CASE(w, b, acq_, 8, a, "memory")
+__CMPXCHG_CASE(w, h, acq_, 16, a, "memory")
+__CMPXCHG_CASE(w, , acq_, 32, a, "memory")
+__CMPXCHG_CASE(x, , acq_, 64, a, "memory")
+__CMPXCHG_CASE(w, b, rel_, 8, l, "memory")
+__CMPXCHG_CASE(w, h, rel_, 16, l, "memory")
+__CMPXCHG_CASE(w, , rel_, 32, l, "memory")
+__CMPXCHG_CASE(x, , rel_, 64, l, "memory")
+__CMPXCHG_CASE(w, b, mb_, 8, al, "memory")
+__CMPXCHG_CASE(w, h, mb_, 16, al, "memory")
+__CMPXCHG_CASE(w, , mb_, 32, al, "memory")
+__CMPXCHG_CASE(x, , mb_, 64, al, "memory")
#undef __LL_SC_CMPXCHG
#undef __CMPXCHG_CASE