asm-generic: provide entirely generic nommu uaccess

Move the code to implement uaccess using memcpy or direct loads and
stores to asm-generic/uaccess.h and make it selectable kconfig option.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

diff --git a/arch/h8300/Kconfig b/arch/h8300/Kconfig
index c071da34e0817be181e82ac3d7a9ca7eea85450c..c24d3624150388ff839f261b91b48ca197cb6fe2 100644 (file)
--- a/arch/h8300/Kconfig
+++ b/arch/h8300/Kconfig
@@ -23,6 +23,7 @@ config H8300
        select HAVE_ARCH_KGDB
        select HAVE_ARCH_HASH
        select CPU_NO_EFFICIENT_FFS
+       select UACCESS_MEMCPY
 
 config CPU_BIG_ENDIAN
        def_bool y

diff --git a/arch/h8300/include/asm/Kbuild b/arch/h8300/include/asm/Kbuild
index 3e7c8ecf151e13841d0c3e491f3927aa1586434c..988533f02e4af8c4653b37597ac402efb26d4cc8 100644 (file)
--- a/arch/h8300/include/asm/Kbuild
+++ b/arch/h8300/include/asm/Kbuild
@@ -46,6 +46,7 @@ generic-y += timex.h
 generic-y += tlbflush.h
 generic-y += topology.h
 generic-y += trace_clock.h
+generic-y += uaccess.h
 generic-y += unaligned.h
 generic-y += vga.h
 generic-y += word-at-a-time.h

diff --git a/arch/h8300/include/asm/uaccess.h b/arch/h8300/include/asm/uaccess.h
deleted file mode 100644 (file)
index bc80319..0000000
--- a/arch/h8300/include/asm/uaccess.h
+++ /dev/null
@@ -1,55 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ASM_UACCESS_H
-#define _ASM_UACCESS_H
-
-#include <linux/string.h>
-
-static inline __must_check unsigned long
-raw_copy_from_user(void *to, const void __user * from, unsigned long n)
-{
-       if (__builtin_constant_p(n)) {
-               switch(n) {
-               case 1:
-                       *(u8 *)to = *(u8 __force *)from;
-                       return 0;
-               case 2:
-                       *(u16 *)to = *(u16 __force *)from;
-                       return 0;
-               case 4:
-                       *(u32 *)to = *(u32 __force *)from;
-                       return 0;
-               }
-       }
-
-       memcpy(to, (const void __force *)from, n);
-       return 0;
-}
-
-static inline __must_check unsigned long
-raw_copy_to_user(void __user *to, const void *from, unsigned long n)
-{
-       if (__builtin_constant_p(n)) {
-               switch(n) {
-               case 1:
-                       *(u8 __force *)to = *(u8 *)from;
-                       return 0;
-               case 2:
-                       *(u16 __force *)to = *(u16 *)from;
-                       return 0;
-               case 4:
-                       *(u32 __force *)to = *(u32 *)from;
-                       return 0;
-               default:
-                       break;
-               }
-       }
-
-       memcpy((void __force *)to, from, n);
-       return 0;
-}
-#define INLINE_COPY_FROM_USER
-#define INLINE_COPY_TO_USER
-
-#include <asm-generic/uaccess.h>
-
-#endif

diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h
index aac336831204d033e8199205845312455595c17e..3dcabfceb21e347b84ef4ad028f6085bbc6acf2b 100644 (file)
--- a/include/asm-generic/uaccess.h
+++ b/include/asm-generic/uaccess.h
@@ -9,6 +9,54 @@
  */
 #include <linux/string.h>
 
+#ifdef CONFIG_UACCESS_MEMCPY
+static inline __must_check unsigned long
+raw_copy_from_user(void *to, const void __user * from, unsigned long n)
+{
+       if (__builtin_constant_p(n)) {
+               switch(n) {
+               case 1:
+                       *(u8 *)to = *(u8 __force *)from;
+                       return 0;
+               case 2:
+                       *(u16 *)to = *(u16 __force *)from;
+                       return 0;
+               case 4:
+                       *(u32 *)to = *(u32 __force *)from;
+                       return 0;
+               }
+       }
+
+       memcpy(to, (const void __force *)from, n);
+       return 0;
+}
+
+static inline __must_check unsigned long
+raw_copy_to_user(void __user *to, const void *from, unsigned long n)
+{
+       if (__builtin_constant_p(n)) {
+               switch(n) {
+               case 1:
+                       *(u8 __force *)to = *(u8 *)from;
+                       return 0;
+               case 2:
+                       *(u16 __force *)to = *(u16 *)from;
+                       return 0;
+               case 4:
+                       *(u32 __force *)to = *(u32 *)from;
+                       return 0;
+               default:
+                       break;
+               }
+       }
+
+       memcpy((void __force *)to, from, n);
+       return 0;
+}
+#define INLINE_COPY_FROM_USER
+#define INLINE_COPY_TO_USER
+#endif /* CONFIG_UACCESS_MEMCPY */
+
 #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
 
 #ifndef KERNEL_DS

diff --git a/lib/Kconfig b/lib/Kconfig
index a9e56539bd11687881ec3e43c1e11cd85d8a4157..7a3f01ac45e8db5f4474d72d5df4677d8ccd6d95 100644 (file)
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -591,6 +591,10 @@ config ARCH_NO_SG_CHAIN
 config ARCH_HAS_PMEM_API
        bool
 
+# use memcpy to implement user copies for nommu architectures
+config UACCESS_MEMCPY
+       bool
+
 config ARCH_HAS_UACCESS_FLUSHCACHE
        bool