microblaze: uaccess: fix clean user macro

This is the first patch which does uaccess unification.
I choosed to do several patches to be able to use bisect
in future if any fault happens.

Signed-off-by: Michal Simek <monstr@monstr.eu>

diff --git a/arch/microblaze/include/asm/uaccess.h b/arch/microblaze/include/asm/uaccess.h
index ce5defb..fdb1c1c 100644 (file)
--- a/arch/microblaze/include/asm/uaccess.h
+++ b/arch/microblaze/include/asm/uaccess.h
@@ -71,8 +71,6 @@ struct exception_table_entry {
        unsigned long insn, fixup;
 };
 
-#define __clear_user(addr, n)  (memset((void *)(addr), 0, (n)), 0)
-
 #ifndef CONFIG_MMU
 
 /* Check against bounds of physical memory */
@@ -86,7 +84,31 @@ static inline int ___range_ok(unsigned long addr, unsigned long size)
                ___range_ok((unsigned long)(addr), (unsigned long)(size))
 
 #define access_ok(type, addr, size) (__range_ok((addr), (size)) == 0)
-#define __access_ok(add, size) (__range_ok((addr), (size)) == 0)
+
+#else
+
+/*
+ * Address is valid if:
+ *  - "addr", "addr + size" and "size" are all below the limit
+ */
+#define access_ok(type, addr, size) \
+       (get_fs().seg > (((unsigned long)(addr)) | \
+               (size) | ((unsigned long)(addr) + (size))))
+
+/* || printk("access_ok failed for %s at 0x%08lx (size %d), seg 0x%08x\n",
+ type?"WRITE":"READ",addr,size,get_fs().seg)) */
+
+#endif
+
+#ifdef CONFIG_MMU
+# define __FIXUP_SECTION       ".section .fixup,\"ax\"\n"
+# define __EX_TABLE_SECTION    ".section __ex_table,\"a\"\n"
+#else
+# define __FIXUP_SECTION       ".section .discard,\"ax\"\n"
+# define __EX_TABLE_SECTION    ".section .discard,\"a\"\n"
+#endif
+
+#ifndef CONFIG_MMU
 
 /* Undefined function to trigger linker error */
 extern int bad_user_access_length(void);
@@ -151,6 +173,9 @@ extern int bad_user_access_length(void);
 #define __copy_from_user_inatomic(to, from, n) \
                        (__copy_from_user((to), (from), (n)))
 
+#define __clear_user(addr, n)  (memset((void *)(addr), 0, (n)), 0)
+
+/* stejne s MMU */
 static inline unsigned long clear_user(void *addr, unsigned long size)
 {
        if (access_ok(VERIFY_WRITE, addr, size))
@@ -167,17 +192,6 @@ extern long strnlen_user(const char *src, long count);
 #else /* CONFIG_MMU */
 
 /*
- * Address is valid if:
- *  - "addr", "addr + size" and "size" are all below the limit
- */
-#define access_ok(type, addr, size) \
-       (get_fs().seg > (((unsigned long)(addr)) | \
-               (size) | ((unsigned long)(addr) + (size))))
-
-/* || printk("access_ok failed for %s at 0x%08lx (size %d), seg 0x%08x\n",
- type?"WRITE":"READ",addr,size,get_fs().seg)) */
-
-/*
  * All the __XXX versions macros/functions below do not perform
  * access checking. It is assumed that the necessary checks have been
  * already performed before the finction (macro) is called.
@@ -297,27 +311,34 @@ __asm__ __volatile__ ("   lwi     %0, %1, 0;              \
        );                                                      \
 })
 
-/*
- * Return: number of not copied bytes, i.e. 0 if OK or non-zero if fail.
- */
-static inline int clear_user(char *to, int size)
+/* Return: number of not copied bytes, i.e. 0 if OK or non-zero if fail. */
+static inline unsigned long __must_check __clear_user(void __user *to,
+                                                       unsigned long n)
 {
-       if (size && access_ok(VERIFY_WRITE, to, size)) {
-               __asm__ __volatile__ ("                         \
-                               1:                              \
-                                       sb      r0, %2, r0;     \
-                                       addik   %0, %0, -1;     \
-                                       bneid   %0, 1b;         \
-                                       addik   %2, %2, 1;      \
-                               2:                              \
-                               .section __ex_table,\"a\";      \
-                               .word   1b,2b;                  \
-                               .section .text;"                \
-                       : "=r"(size)                            \
-                       : "0"(size), "r"(to)
-               );
-       }
-       return size;
+       /* normal memset with two words to __ex_table */
+       __asm__ __volatile__ (                          \
+                       "1:     sb      r0, %2, r0;"    \
+                       "       addik   %0, %0, -1;"    \
+                       "       bneid   %0, 1b;"        \
+                       "       addik   %2, %2, 1;"     \
+                       "2:                     "       \
+                       __EX_TABLE_SECTION              \
+                       ".word  1b,2b;"                 \
+                       ".previous;"                    \
+               : "=r"(n)                               \
+               : "0"(n), "r"(to)
+       );
+       return n;
+}
+
+static inline unsigned long __must_check clear_user(void __user *to,
+                                                       unsigned long n)
+{
+       might_sleep();
+       if (unlikely(!access_ok(VERIFY_WRITE, to, n)))
+               return n;
+
+       return __clear_user(to, n);
 }
 
 #define __copy_from_user(to, from, n)  copy_from_user((to), (from), (n))