Commit cbc6e287 authored by Max Filippov's avatar Max Filippov
Browse files

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: default avatarMax Filippov <jcmvbkbc@gmail.com>
parent f5fae679

arch/xtensa/include/asm/uaccess.h

+8 −8
Original line number Diff line number Diff line
@@ -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)