linux.git/drivers/video/fbdev/core/sysimgblt.c, branch v5.10.258

fbdev: fix potential OOB read in fast_imageblit()

2023-08-30T14:23:10+00:00

[ Upstream commit c2d22806aecb24e2de55c30a06e5d6eb297d161d ]

There is a potential OOB read at fast_imageblit, for
"colortab[(*src >> 4)]" can become a negative value due to
"const char *s = image->data, *src".
This change makes sure the index for colortab always positive
or zero.

Similar commit:
https://patchwork.kernel.org/patch/11746067

Potential bug report:
https://groups.google.com/g/syzkaller-bugs/c/9ubBXKeKXf4/m/k-QXy4UgAAAJ

Signed-off-by: Zhang Shurong 
Cc: stable@vger.kernel.org
Signed-off-by: Helge Deller 
Signed-off-by: Sasha Levin

fbdev: Fix sys_imageblit() for arbitrary image widths

2023-08-30T14:23:10+00:00

[ Upstream commit 61bfcb6a3b981e8f19e044ac8c3de6edbe6caf70 ]

Commit 6f29e04938bf ("fbdev: Improve performance of sys_imageblit()")
broke sys_imageblit() for image width that are not aligned to 8-bit
boundaries. Fix this by handling the trailing pixels on each line
separately. The performance improvements in the original commit do not
regress by this change.

Signed-off-by: Thomas Zimmermann 
Fixes: 6f29e04938bf ("fbdev: Improve performance of sys_imageblit()")
Reviewed-by: Javier Martinez Canillas 
Acked-by: Daniel Vetter 
Tested-by: Geert Uytterhoeven 
Cc: Thomas Zimmermann 
Cc: Javier Martinez Canillas 
Cc: Sam Ravnborg 
Link: https://patchwork.freedesktop.org/patch/msgid/20220313192952.12058-2-tzimmermann@suse.de
Stable-dep-of: c2d22806aecb ("fbdev: fix potential OOB read in fast_imageblit()")
Signed-off-by: Sasha Levin

fbdev: Improve performance of sys_imageblit()

2023-08-30T14:23:10+00:00

[ Upstream commit 6f29e04938bf509fccfad490a74284cf158891ce ]

Improve the performance of sys_imageblit() by manually unrolling
the inner blitting loop and moving some invariants out. The compiler
failed to do this automatically. The resulting binary code was even
slower than the cfb_imageblit() helper, which uses the same algorithm,
but operates on I/O memory.

A microbenchmark measures the average number of CPU cycles
for sys_imageblit() after a stabilizing period of a few minutes
(i7-4790, FullHD, simpledrm, kernel with debugging). The value
for CFB is given as a reference.

  sys_imageblit(), new: 25934 cycles
  sys_imageblit(), old: 35944 cycles
  cfb_imageblit():      30566 cycles

In the optimized case, sys_imageblit() is now ~30% faster than before
and ~20% faster than cfb_imageblit().

v2:
	* move switch out of inner loop (Gerd)
	* remove test for alignment of dst1 (Sam)

Signed-off-by: Thomas Zimmermann 
Reviewed-by: Javier Martinez Canillas 
Acked-by: Sam Ravnborg 
Link: https://patchwork.freedesktop.org/patch/msgid/20220223193804.18636-3-tzimmermann@suse.de
Stable-dep-of: c2d22806aecb ("fbdev: fix potential OOB read in fast_imageblit()")
Signed-off-by: Sasha Levin

fbdev: move fbdev core files to separate directory

2014-04-17T05:10:19+00:00

Instead of having fbdev framework core files at the root fbdev
directory, mixed with random fbdev device drivers, move the fbdev core
files to a separate core directory. This makes it much clearer which of
the files are actually part of the fbdev framework, and which are part
of device drivers.

Signed-off-by: Tomi Valkeinen 
Acked-by: Laurent Pinchart 
Acked-by: Geert Uytterhoeven 
Acked-by: Rob Clark 
Acked-by: Jingoo Han 
Acked-by: Daniel Vetter