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, 31 insertions, 0 deletions

diff --git a/arch/sparc/include/asm/io_32.h b/arch/sparc/include/asm/io_32.h
index 2889574608db..c2ced21c9dc1 100644
--- a/arch/sparc/include/asm/io_32.h
+++ b/arch/sparc/include/asm/io_32.h
@@ -208,6 +208,21 @@ _memset_io(volatile void __iomem *dst, int c, __kernel_size_t n)
 #define memset_io(d,c,sz)	_memset_io(d,c,sz)
 
 static inline void
+_sbus_memcpy_fromio(void *dst, const volatile void __iomem *src,
+		    __kernel_size_t n)
+{
+	char *d = dst;
+
+	while (n--) {
+		char tmp = sbus_readb(src);
+		*d++ = tmp;
+		src++;
+	}
+}
+
+#define sbus_memcpy_fromio(d, s, sz)	_sbus_memcpy_fromio(d, s, sz)
+
+static inline void
 _memcpy_fromio(void *dst, const volatile void __iomem *src, __kernel_size_t n)
 {
 	char *d = dst;
@@ -222,6 +237,22 @@ _memcpy_fromio(void *dst, const volatile void __iomem *src, __kernel_size_t n)
 #define memcpy_fromio(d,s,sz)	_memcpy_fromio(d,s,sz)
 
 static inline void
+_sbus_memcpy_toio(volatile void __iomem *dst, const void *src,
+		  __kernel_size_t n)
+{
+	const char *s = src;
+	volatile void __iomem *d = dst;
+
+	while (n--) {
+		char tmp = *s++;
+		sbus_writeb(tmp, d);
+		d++;
+	}
+}
+
+#define sbus_memcpy_toio(d, s, sz)	_sbus_memcpy_toio(d, s, sz)
+
+static inline void
 _memcpy_toio(volatile void __iomem *dst, const void *src, __kernel_size_t n)
 {
 	const char *s = src;