xtensa: use "m" constraint instead of "a" in uaccess.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.
Use %[mem] * 0 + v to replace offset part of %[mem] expansion with v.
It is impossible to change address alignment through the offset part on
xtensa, so just ignore offset in alignment checks.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

diff --git a/arch/xtensa/include/asm/uaccess.h b/arch/xtensa/include/asm/uaccess.h
index 3f80386f18838902b1a96a32c3839cf9979ec436..47b7702aaa40255b91c3d92f1e92740464fd8774 100644 (file)
--- a/arch/xtensa/include/asm/uaccess.h
+++ b/arch/xtensa/include/asm/uaccess.h
@@ -132,13 +132,13 @@ do {                                                                      \
 #define __check_align_1  ""
 
 #define __check_align_2                                \
-       "   _bbci.l %[addr], 0, 1f      \n"     \
+       "   _bbci.l %[mem] * 0, 1f      \n"     \
        "   movi    %[err], %[efault]   \n"     \
        "   _j      2f                  \n"
 
 #define __check_align_4                                \
-       "   _bbsi.l %[addr], 0, 0f      \n"     \
-       "   _bbci.l %[addr], 1, 1f      \n"     \
+       "   _bbsi.l %[mem] * 0, 0f      \n"     \
+       "   _bbci.l %[mem] * 0 + 1, 1f  \n"     \
        "0: movi    %[err], %[efault]   \n"     \
        "   _j      2f                  \n"
 
@@ -154,7 +154,7 @@ do {                                                                        \
 #define __put_user_asm(x_, addr_, err_, align, insn, cb)\
 __asm__ __volatile__(                                  \
        __check_align_##align                           \
-       "1: "insn"  %[x], %[addr], 0    \n"             \
+       "1: "insn"  %[x], %[mem]        \n"             \
        "2:                             \n"             \
        "   .section  .fixup,\"ax\"     \n"             \
        "   .align 4                    \n"             \
@@ -167,8 +167,8 @@ __asm__ __volatile__(                                       \
        "   .section  __ex_table,\"a\"  \n"             \
        "   .long       1b, 5b          \n"             \
        "   .previous"                                  \
-       :[err] "+r"(err_), [tmp] "=r"(cb)               \
-       :[x] "r"(x_), [addr] "r"(addr_), [efault] "i"(-EFAULT))
+       :[err] "+r"(err_), [tmp] "=r"(cb), [mem] "=m"(*(addr_))         \
+       :[x] "r"(x_), [efault] "i"(-EFAULT))
 
 #define __get_user_nocheck(x, ptr, size)                       \
 ({                                                             \
@@ -222,7 +222,7 @@ do {                                                        \
        u32 __x = 0;                                    \
        __asm__ __volatile__(                           \
                __check_align_##align                   \
-               "1: "insn"  %[x], %[addr], 0    \n"     \
+               "1: "insn"  %[x], %[mem]        \n"     \
                "2:                             \n"     \
                "   .section  .fixup,\"ax\"     \n"     \
                "   .align 4                    \n"     \
@@ -236,7 +236,7 @@ do {                                                        \
                "   .long       1b, 5b          \n"     \
                "   .previous"                          \
                :[err] "+r"(err_), [tmp] "=r"(cb), [x] "+r"(__x) \
-               :[addr] "r"(addr_), [efault] "i"(-EFAULT)); \
+               :[mem] "m"(*(addr_)), [efault] "i"(-EFAULT)); \
        (x_) = (__force __typeof__(*(addr_)))__x;       \
 } while (0)