xtensa: use "m" constraint instead of "r" in futex.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>

diff --git a/arch/xtensa/include/asm/futex.h b/arch/xtensa/include/asm/futex.h
index 0c4457c..9646110 100644 (file)
--- a/arch/xtensa/include/asm/futex.h
+++ b/arch/xtensa/include/asm/futex.h
@@ -43,10 +43,10 @@
 #elif XCHAL_HAVE_S32C1I
 #define __futex_atomic_op(insn, ret, old, uaddr, arg)  \
        __asm__ __volatile(                             \
-       "1:     l32i    %[oldval], %[addr], 0\n"        \
+       "1:     l32i    %[oldval], %[mem]\n"            \
                insn "\n"                               \
        "       wsr     %[oldval], scompare1\n"         \
-       "2:     s32c1i  %[newval], %[addr], 0\n"        \
+       "2:     s32c1i  %[newval], %[mem]\n"            \
        "       bne     %[newval], %[oldval], 1b\n"     \
        "       movi    %[newval], 0\n"                 \
        "3:\n"                                          \
@@ -60,9 +60,9 @@
        "       .section __ex_table,\"a\"\n"            \
        "       .long 1b, 5b, 2b, 5b\n"                 \
        "       .previous\n"                            \
-       : [oldval] "=&r" (old), [newval] "=&r" (ret)    \
-       : [addr] "r" (uaddr), [oparg] "r" (arg),        \
-         [fault] "I" (-EFAULT)                         \
+       : [oldval] "=&r" (old), [newval] "=&r" (ret),   \
+         [mem] "+m" (*(uaddr))                         \
+       : [oparg] "r" (arg), [fault] "I" (-EFAULT)      \
        : "memory")
 #endif