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Commit 70e137eb authored by Chris Zankel's avatar Chris Zankel
Browse files

[XTENSA] Fix clobbered register in asm macro 



We dangerously re-used an input operand to an asm macro
without defining a constraint. By defining a separate
output operand (instead of input/output operand), the
compiler is more flexible during register allocation.

Signed-off-by: default avatarChris Zankel <chris@zankel.net>
parent c8654158

include/asm-xtensa/uaccess.h

+51 −48
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
#include <asm/current.h>

#include <asm/asm-offsets.h>

#include <asm/processor.h>

#include <asm/types.h>



/*

 * These assembly macros mirror the C macros that follow below.  They
@@ -118,7 +119,7 @@ 
 * 	<at>	destroyed (actually, (TASK_SIZE + 1 - size))

 */

	.macro	user_ok	aa, as, at, error

	movi	\at, (TASK_SIZE+1)

	movi	\at, __XTENSA_UL_CONST(TASK_SIZE)

	bgeu	\as, \at, \error

	sub	\at, \at, \as

	bgeu	\aa, \at, \error
@@ -228,11 +229,12 @@ extern long __put_user_bad(void); 


#define __put_user_size(x,ptr,size,retval)				\

do {									\

	int __cb;							\

	retval = 0;							\

	switch (size) {							\

        case 1: __put_user_asm(x,ptr,retval,1,"s8i");  break;	\

        case 2: __put_user_asm(x,ptr,retval,2,"s16i"); break;   \

        case 4: __put_user_asm(x,ptr,retval,4,"s32i"); break;   \

        case 1: __put_user_asm(x,ptr,retval,1,"s8i",__cb);  break;	\

        case 2: __put_user_asm(x,ptr,retval,2,"s16i",__cb); break;	\

        case 4: __put_user_asm(x,ptr,retval,4,"s32i",__cb); break;	\

        case 8: {							\

		     __typeof__(*ptr) __v64 = x;			\

		     retval = __copy_to_user(ptr,&__v64,8);		\
@@ -267,14 +269,14 @@ do { \ 
#define __check_align_1  ""



#define __check_align_2				\

	"   _bbci.l %2,  0, 1f		\n"	\

	"   movi    %0, %3		\n"	\

	"   _bbci.l %3,  0, 1f		\n"	\

	"   movi    %0, %4		\n"	\

	"   _j      2f			\n"



#define __check_align_4				\

	"   _bbsi.l %2,  0, 0f		\n"	\

	"   _bbci.l %2,  1, 1f		\n"	\

	"0: movi    %0, %3		\n"	\

	"   _bbsi.l %3,  0, 0f		\n"	\

	"   _bbci.l %3,  1, 1f		\n"	\

	"0: movi    %0, %4		\n"	\

	"   _j      2f			\n"
@@ -286,24 +288,24 @@ do { \ 
 * WARNING: If you modify this macro at all, verify that the

 * __check_align_* macros still work.

 */

#define __put_user_asm(x, addr, err, align, insn) \

#define __put_user_asm(x, addr, err, align, insn, cb)	\

   __asm__ __volatile__(				\

	__check_align_##align				\

	"1: "insn"  %1, %2, 0		\n"	\

	"1: "insn"  %2, %3, 0		\n"		\

	"2:				\n"		\

	"   .section  .fixup,\"ax\"	\n"		\

	"   .align 4			\n"		\

	"4:				\n"		\

	"   .long  2b			\n"		\

	"5:				\n"		\

	"   l32r   %2, 4b		\n"	\

        "   movi   %0, %3		\n"	\

        "   jx     %2			\n"	\

	"   l32r   %1, 4b		\n"		\

        "   movi   %0, %4		\n"		\

        "   jx     %1			\n"		\

	"   .previous			\n"		\

	"   .section  __ex_table,\"a\"	\n"		\

	"   .long	1b, 5b		\n"		\

	"   .previous"					\

	:"=r" (err)				\

	:"=r" (err), "=r" (cb)				\

	:"r" ((int)(x)), "r" (addr), "i" (-EFAULT), "0" (err))



#define __get_user_nocheck(x,ptr,size)				\
@@ -328,11 +330,12 @@ extern long __get_user_bad(void); 


#define __get_user_size(x,ptr,size,retval)				\

do {									\

	int __cb;							\

	retval = 0;							\

        switch (size) {							\

          case 1: __get_user_asm(x,ptr,retval,1,"l8ui");  break;	\

          case 2: __get_user_asm(x,ptr,retval,2,"l16ui"); break;	\

          case 4: __get_user_asm(x,ptr,retval,4,"l32i");  break;	\

          case 1: __get_user_asm(x,ptr,retval,1,"l8ui",__cb);  break;	\

          case 2: __get_user_asm(x,ptr,retval,2,"l16ui",__cb); break;	\

          case 4: __get_user_asm(x,ptr,retval,4,"l32i",__cb);  break;	\

          case 8: retval = __copy_from_user(&x,ptr,8);    break;	\

          default: (x) = __get_user_bad();				\

        }								\
@@ -343,25 +346,25 @@ do { \ 
 * WARNING: If you modify this macro at all, verify that the

 * __check_align_* macros still work.

 */

#define __get_user_asm(x, addr, err, align, insn) \

#define __get_user_asm(x, addr, err, align, insn, cb) \

   __asm__ __volatile__(			\

	__check_align_##align			\

	"1: "insn"  %1, %2, 0		\n"	\

	"1: "insn"  %2, %3, 0		\n"	\

	"2:				\n"	\

	"   .section  .fixup,\"ax\"	\n"	\

	"   .align 4			\n"	\

	"4:				\n"	\

	"   .long  2b			\n"	\

	"5:				\n"	\

	"   l32r   %2, 4b		\n"	\

	"   movi   %1, 0		\n"	\

        "   movi   %0, %3		\n"	\

        "   jx     %2			\n"	\

	"   l32r   %1, 4b		\n"	\

	"   movi   %2, 0		\n"	\

        "   movi   %0, %4		\n"	\

        "   jx     %1			\n"	\

	"   .previous			\n"	\

	"   .section  __ex_table,\"a\"	\n"	\

	"   .long	1b, 5b		\n"	\

	"   .previous"				\

	:"=r" (err), "=r" (x)			\

	:"=r" (err), "=r" (cb), "=r" (x)	\

	:"r" (addr), "i" (-EFAULT), "0" (err))