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

commit 28668f43b8e421634e1623f72a879812288dd06b upstream.

The patch f045f459d925 ("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
f045f459d925 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 f045f459d925 was
backported.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: f045f459d925 ("drm/nouveau/fbcon: fix out-of-bounds memory accesses")
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/nouveau/nv04_fbcon.c b/drivers/gpu/drm/nouveau/nv04_fbcon.c
index 8f715fe..f905683 100644 (file)
--- a/drivers/gpu/drm/nouveau/nv04_fbcon.c
+++ b/drivers/gpu/drm/nouveau/nv04_fbcon.c
@@ -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;
 

diff --git a/drivers/gpu/drm/nouveau/nv50_fbcon.c b/drivers/gpu/drm/nouveau/nv50_fbcon.c
index a4e259a..c8e0965 100644 (file)
--- a/drivers/gpu/drm/nouveau/nv50_fbcon.c
+++ b/drivers/gpu/drm/nouveau/nv50_fbcon.c
@@ -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;
 

diff --git a/drivers/gpu/drm/nouveau/nvc0_fbcon.c b/drivers/gpu/drm/nouveau/nvc0_fbcon.c
index f28315e..22d3257 100644 (file)
--- a/drivers/gpu/drm/nouveau/nvc0_fbcon.c
+++ b/drivers/gpu/drm/nouveau/nvc0_fbcon.c
@@ -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;