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drm/nouveau/fbcon: fix font width not divisible by 8

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The patch f045f459d9 ("drm/nouveau/fbcon: fix out-of-bounds memory accesses")
tries to fix some out of memory accesses. Unfortunatelly, the patch breaks the
display when using fonts with width that is not divisiable by 8.

The monochrome bitmap for each character is stored in memory by lines from top
to bottom. Each line is padded to a full byte.

For example, for 22x11 font, each line is padded to 16 bits, so each
character is consuming 44 bytes total, that is 11 32-bit words. The patch
f045f459d9 changed the logic to "dsize = ALIGN(image->width *
image->height, 32) >> 5", that is just 8 words - this is incorrect and it
causes display corruption.

This patch adds the necesary padding of lines to 8 bytes.

This patch should be backported to stable kernels where f045f459d9 was
backported.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: f045f459d9 ("drm/nouveau/fbcon: fix out-of-bounds memory accesses")
Cc: stable@vger.kernel.org
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
This commit is contained in:
Mikulas Patocka 2016-07-28 18:56:13 -04:00 committed by Ben Skeggs
parent c11dea5b02
commit 28668f43b8
3 changed files with 4 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/gpu/drm/nouveau/nv04_fbcon.c
View File

@ -107,11 +107,11 @@ nv04_fbcon_imageblit(struct fb_info *info, const struct fb_image *image)
((image->dx + image->width) & 0xffff));
OUT_RING(chan, bg);
OUT_RING(chan, fg);
OUT_RING(chan, (image->height << 16) | image->width);
OUT_RING(chan, (image->height << 16) | ALIGN(image->width, 8));
OUT_RING(chan, (image->height << 16) | image->width);
OUT_RING(chan, (image->dy << 16) | (image->dx & 0xffff));
dsize = ALIGN(image->width * image->height, 32) >> 5;
dsize = ALIGN(ALIGN(image->width, 8) * image->height, 32) >> 5;
while (dsize) {
int iter_len = dsize > 128 ? 128 : dsize;

2
drivers/gpu/drm/nouveau/nv50_fbcon.c
View File

@ -125,7 +125,7 @@ nv50_fbcon_imageblit(struct fb_info *info, const struct fb_image *image)
OUT_RING(chan, 0);
OUT_RING(chan, image->dy);
dwords = ALIGN(image->width * image->height, 32) >> 5;
dwords = ALIGN(ALIGN(image->width, 8) * image->height, 32) >> 5;
while (dwords) {
int push = dwords > 2047 ? 2047 : dwords;

2
drivers/gpu/drm/nouveau/nvc0_fbcon.c
View File

@ -125,7 +125,7 @@ nvc0_fbcon_imageblit(struct fb_info *info, const struct fb_image *image)
OUT_RING (chan, 0);
OUT_RING (chan, image->dy);
dwords = ALIGN(image->width * image->height, 32) >> 5;
dwords = ALIGN(ALIGN(image->width, 8) * image->height, 32) >> 5;
while (dwords) {
int push = dwords > 2047 ? 2047 : dwords;