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xtensa: use "m" constraint instead of "a" in cmpxchg.h assembly 

Use "m" constraint instead of "r" for the address, as "m" allows
compiler to access adjacent locations using base + offset, while "r"
requires updating the base register every time.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
This commit is contained in:
Max Filippov 2019-10-16 00:49:54 -07:00
parent 812e708a4c
commit cf3b3baa71
1 changed files with 16 additions and 15 deletions
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31
arch/xtensa/include/asm/cmpxchg.h
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@ -43,9 +43,9 @@ __cmpxchg_u32(volatile int *p, int old, int new)
#elif XCHAL_HAVE_S32C1I
__asm__ __volatile__(
" wsr %[cmp], scompare1\n"
" s32c1i %[new], %[addr], 0\n"
: [new] "+a" (new)
: [addr] "a" (p), [cmp] "a" (old)
" s32c1i %[new], %[mem]\n"
: [new] "+a" (new), [mem] "+m" (*p)
: [cmp] "a" (old)
: "memory"
);
@ -53,14 +53,14 @@ __cmpxchg_u32(volatile int *p, int old, int new)
#else
__asm__ __volatile__(
" rsil a15, "__stringify(TOPLEVEL)"\n"
" l32i %[old], %[addr], 0\n"
" l32i %[old], %[mem]\n"
" bne %[old], %[cmp], 1f\n"
" s32i %[new], %[addr], 0\n"
" s32i %[new], %[mem]\n"
"1:\n"
" wsr a15, ps\n"
" rsync\n"
: [old] "=&a" (old)
: [addr] "a" (p), [cmp] "a" (old), [new] "r" (new)
: [old] "=&a" (old), [mem] "+m" (*p)
: [cmp] "a" (old), [new] "r" (new)
: "a15", "memory");
return old;
#endif
@ -143,13 +143,14 @@ static inline unsigned long xchg_u32(volatile int * m, unsigned long val)
#elif XCHAL_HAVE_S32C1I
unsigned long tmp, result;
__asm__ __volatile__(
"1: l32i %[tmp], %[addr], 0\n"
"1: l32i %[tmp], %[mem]\n"
" mov %[result], %[val]\n"
" wsr %[tmp], scompare1\n"
" s32c1i %[result], %[addr], 0\n"
" s32c1i %[result], %[mem]\n"
" bne %[result], %[tmp], 1b\n"
: [result] "=&a" (result), [tmp] "=&a" (tmp)
: [addr] "a" (m), [val] "a" (val)
: [result] "=&a" (result), [tmp] "=&a" (tmp),
[mem] "+m" (*m)
: [val] "a" (val)
: "memory"
);
return result;
@ -157,12 +158,12 @@ static inline unsigned long xchg_u32(volatile int * m, unsigned long val)
unsigned long tmp;
__asm__ __volatile__(
" rsil a15, "__stringify(TOPLEVEL)"\n"
" l32i %[tmp], %[addr], 0\n"
" s32i %[val], %[addr], 0\n"
" l32i %[tmp], %[mem]\n"
" s32i %[val], %[mem]\n"
" wsr a15, ps\n"
" rsync\n"
: [tmp] "=&a" (tmp)
: [addr] "a" (m), [val] "a" (val)
: [tmp] "=&a" (tmp), [mem] "+m" (*m)
: [val] "a" (val)
: "a15", "memory");
return tmp;
#endif