1 files changed, 66 insertions, 23 deletions

diff --git a/arch/microblaze/include/asm/uaccess.h b/arch/microblaze/include/asm/uaccess.h
index 1af92025fff9..b079ac31a671 100644
--- a/arch/microblaze/include/asm/uaccess.h
+++ b/arch/microblaze/include/asm/uaccess.h
@@ -146,31 +146,75 @@ static inline unsigned long __must_check clear_user(void __user *to,
 
 #ifndef CONFIG_MMU
 
-/* Undefined function to trigger linker error */
-extern int bad_user_access_length(void);
+extern long __user_bad(void);
+
+#define __get_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
+({                                                              \
+        __asm__ __volatile__ (                                  \
+                        "1:"    insn    " %1, %2, r0;"          \
+                        "       addk    %0, r0, r0;"            \
+                        "2:                     "               \
+                        __FIXUP_SECTION                         \
+                        "3:     brid    2b;"                    \
+                        "       addik   %0, r0, %3;"            \
+                        ".previous;"                            \
+                        __EX_TABLE_SECTION                      \
+                        ".word  1b,3b;"                         \
+                        ".previous;"                            \
+                : "=&r"(__gu_err), "=r"(__gu_val)               \
+                : "r"(__gu_ptr), "i"(-EFAULT)                   \
+        );                                                      \
+})
+
+/**
+ * get_user: - Get a simple variable from user space.
+ * @x:   Variable to store result.
+ * @ptr: Source address, in user space.
+ *
+ * Context: User context only.  This function may sleep.
+ *
+ * This macro copies a single simple variable from user space to kernel
+ * space.  It supports simple types like char and int, but not larger
+ * data types like structures or arrays.
+ *
+ * @ptr must have pointer-to-simple-variable type, and the result of
+ * dereferencing @ptr must be assignable to @x without a cast.
+ *
+ * Returns zero on success, or -EFAULT on error.
+ * On error, the variable @x is set to zero.
+ */
+
+#define __get_user(x, ptr)                                              \
+({                                                                      \
+        unsigned long __gu_val;                                         \
+        /*unsigned long __gu_ptr = (unsigned long)(ptr);*/              \
+        long __gu_err;                                                  \
+        switch (sizeof(*(ptr))) {                                       \
+        case 1:                                                         \
+                __get_user_asm("lbu", (ptr), __gu_val, __gu_err);       \
+                break;                                                  \
+        case 2:                                                         \
+                __get_user_asm("lhu", (ptr), __gu_val, __gu_err);       \
+                break;                                                  \
+        case 4:                                                         \
+                __get_user_asm("lw", (ptr), __gu_val, __gu_err);        \
+                break;                                                  \
+        default:                                                        \
+                /* __gu_val = 0; __gu_err = -EINVAL;*/ __gu_err = __user_bad();\
+        }                                                               \
+        x = (__typeof__(*(ptr))) __gu_val;                              \
+        __gu_err;                                                       \
+})
+
 
-/* FIXME this is function for optimalization -> memcpy */
-#define __get_user(var, ptr)                            \
-({                                                      \
-        int __gu_err = 0;                               \
-        switch (sizeof(*(ptr))) {                       \
-        case 1:                                         \
-        case 2:                                         \
-        case 4:                                         \
-                (var) = *(ptr);                         \
-                break;                                  \
-        case 8:                                         \
-                memcpy((void *) &(var), (ptr), 8);      \
-                break;                                  \
-        default:                                        \
-                (var) = 0;                              \
-                __gu_err = __get_user_bad();            \
-                break;                                  \
-        }                                               \
-        __gu_err;                                       \
+#define get_user(x, ptr)                                                \
+({                                                                      \
+        access_ok(VERIFY_READ, (ptr), sizeof(*(ptr)))                   \
+                ? __get_user((x), (ptr)) : -EFAULT;                     \
 })
 
-#define __get_user_bad()        (bad_user_access_length(), (-EFAULT))
+/* Undefined function to trigger linker error */
+extern int bad_user_access_length(void);
 
 /* FIXME is not there defined __pu_val */
 #define __put_user(var, ptr)                                    \
@@ -197,7 +241,6 @@ extern int bad_user_access_length(void);
 #define __put_user_bad()        (bad_user_access_length(), (-EFAULT))
 
 #define put_user(x, ptr)        __put_user((x), (ptr))
-#define get_user(x, ptr)        __get_user((x), (ptr))
 
 #define copy_to_user(to, from, n)       (memcpy((to), (from), (n)), 0)
 #define copy_from_user(to, from, n)     (memcpy((to), (from), (n)), 0)