[PATCH] fbcon: Console Rotation - Fix wrong shift calculation

The shift value (amount to shift the bitmap so first pixel starts at
origin(0,0)) is incorrect. This causes corrupted characters or a kernel crash
if fontwidth is not divisible by 8 at 270 degrees, or fontheight not divisible
by 8 at 180 degrees.

Report and part of the fix contributed by Knut Petersen.

Signed-off-by: Antonino Daplas <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/video/console/fbcon_rotate.h

···
 static inline void rotate_ud(const char *in, char *out, u32 width, u32 height)
 {
 	int i, j;
-	int shift = width % 8;
+	int shift = (8 - (width % 8)) & 7;
 
 	width = (width + 7) & ~7;
 
···
 static inline void rotate_ccw(const char *in, char *out, u32 width, u32 height)
 {
 	int i, j, h = height, w = width;
-	int shift = width % 8;
+	int shift = (8 - (width % 8)) & 7;
 
 	width = (width + 7) & ~7;
 	height = (height + 7) & ~7;