x86: merge getuser.

Merge versions of getuser from uaccess_32.h and uaccess_64.h into
uaccess.h. There is a part which is 64-bit only (for now), and for
that, we use a __get_user_8 macro.

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 55 insertions, 0 deletions

diff --git a/include/asm-x86/uaccess.h b/include/asm-x86/uaccess.h
index 2fc30c2a8a98..8cb580c0b411 100644
--- a/include/asm-x86/uaccess.h
+++ b/include/asm-x86/uaccess.h
@@ -120,6 +120,61 @@ extern int __get_user_bad(void);
                      : "=a" (ret),"=d" (x)            \
                      : "0" (ptr))                     \
 
+/* Careful: we have to cast the result to the type of the pointer
+ * for sign reasons */
+
+/**
+ * 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.
+ */
+#ifdef CONFIG_X86_32
+#define __get_user_8(__ret_gu, __val_gu, ptr)                           \
+                __get_user_x(X, __ret_gu, __val_gu, ptr)
+#else
+#define __get_user_8(__ret_gu, __val_gu, ptr)                           \
+                __get_user_x(8, __ret_gu, __val_gu, ptr)
+#endif
+
+#define get_user(x, ptr)                                                \
+({                                                                      \
+        int __ret_gu;                                                   \
+        unsigned long __val_gu;                                         \
+        __chk_user_ptr(ptr);                                            \
+        switch (sizeof(*(ptr))) {                                       \
+        case 1:                                                         \
+                __get_user_x(1, __ret_gu, __val_gu, ptr);               \
+                break;                                                  \
+        case 2:                                                         \
+                __get_user_x(2, __ret_gu, __val_gu, ptr);               \
+                break;                                                  \
+        case 4:                                                         \
+                __get_user_x(4, __ret_gu, __val_gu, ptr);               \
+                break;                                                  \
+        case 8:                                                         \
+                __get_user_8(__ret_gu, __val_gu, ptr);                  \
+                break;                                                  \
+        default:                                                        \
+                __get_user_x(X, __ret_gu, __val_gu, ptr);               \
+                break;                                                  \
+        }                                                               \
+        (x) = (__typeof__(*(ptr)))__val_gu;                             \
+        __ret_gu;                                                       \
+})
+
+
 #ifdef CONFIG_X86_32
 # include "uaccess_32.h"
 #else