fbmem: fix fb_read, fb_write unaligned accesses

fb_{read,write} access the framebuffer using lots of fb_{read,write}l's
but don't check that the file position is aligned which can cause problems
on some architectures which do not support unaligned accesses.

Since the operations are essentially memcpy_{from,to}io, new
fb_memcpy_{from,to}fb macros have been defined and these are used instead.

For Sparc, fb_{read,write} macros use sbus_{read,write}, so this defines
new sbus_memcpy_{from,to}io functions the same as memcpy_{from,to}io but
using sbus_{read,write}b instead of {read,write}b.

Signed-off-by: James Hogan <james@albanarts.com>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/fb.h b/include/linux/fb.h
index f0268de..7fca3dc 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -931,6 +931,8 @@ static inline struct apertures_struct *alloc_apertures(unsigned int max_num) {
 #define fb_writel sbus_writel
 #define fb_writeq sbus_writeq
 #define fb_memset sbus_memset_io
+#define fb_memcpy_fromfb sbus_memcpy_fromio
+#define fb_memcpy_tofb sbus_memcpy_toio
 
 #elif defined(__i386__) || defined(__alpha__) || defined(__x86_64__) || defined(__hppa__) || defined(__sh__) || defined(__powerpc__) || defined(__avr32__) || defined(__bfin__)
 
@@ -943,6 +945,8 @@ static inline struct apertures_struct *alloc_apertures(unsigned int max_num) {
 #define fb_writel __raw_writel
 #define fb_writeq __raw_writeq
 #define fb_memset memset_io
+#define fb_memcpy_fromfb memcpy_fromio
+#define fb_memcpy_tofb memcpy_toio
 
 #else
 
@@ -955,6 +959,8 @@ static inline struct apertures_struct *alloc_apertures(unsigned int max_num) {
 #define fb_writel(b,addr) (*(volatile u32 *) (addr) = (b))
 #define fb_writeq(b,addr) (*(volatile u64 *) (addr) = (b))
 #define fb_memset memset
+#define fb_memcpy_fromfb memcpy
+#define fb_memcpy_tofb memcpy
 
 #endif