[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: Chris Zankel <chris@zankel.net>

diff --git a/include/asm-xtensa/uaccess.h b/include/asm-xtensa/uaccess.h
index d6352da05b10b9b29660b5121581dc44ae838423..b8528426ab1f0c8174db560b2caf6bdb5168cea9 100644 (file)
--- a/include/asm-xtensa/uaccess.h
+++ b/include/asm-xtensa/uaccess.h
@@ -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
@@ -226,20 +227,21 @@ extern long __put_user_bad(void);
        __pu_err;                                               \
 })
 
-#define __put_user_size(x,ptr,size,retval)                     \
-do {                                                           \
-       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 8: {                                              \
-                    __typeof__(*ptr) __v64 = x;                \
-                    retval = __copy_to_user(ptr,&__v64,8);     \
-                    break;                                     \
-               }                                               \
-       default: __put_user_bad();                              \
-       }                                                       \
+#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",__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);             \
+                    break;                                             \
+               }                                                       \
+       default: __put_user_bad();                                      \
+       }                                                               \
 } while (0)
 
 
@@ -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) \
-   __asm__ __volatile__(                       \
-       __check_align_##align                   \
-       "1: "insn"  %1, %2, 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"     \
-       "   .previous                   \n"     \
-       "   .section  __ex_table,\"a\"  \n"     \
-       "   .long       1b, 5b          \n"     \
-       "   .previous"                          \
-       :"=r" (err)                             \
+#define __put_user_asm(x, addr, err, align, insn, cb)  \
+   __asm__ __volatile__(                               \
+       __check_align_##align                           \
+       "1: "insn"  %2, %3, 0           \n"             \
+       "2:                             \n"             \
+       "   .section  .fixup,\"ax\"     \n"             \
+       "   .align 4                    \n"             \
+       "4:                             \n"             \
+       "   .long  2b                   \n"             \
+       "5:                             \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" (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))