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video: fbdev: fsl-diu-fb: Remove VLA usage

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In the quest to remove all stack VLA usage from the kernel[1], this moves
the buffer off the stack (since it could be as much as 1024 bytes), and
uses a new area in the cursor data structure. Additionally adds missed
documentation and removes redundant assignments.

[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com

Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Timur Tabi <timur@kernel.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
This commit is contained in:
Kees Cook 2018-07-24 19:11:26 +02:00 committed by Bartlomiej Zolnierkiewicz
parent 31e1391af2
commit 4a1208c5b4
1 changed files with 13 additions and 10 deletions
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23
drivers/video/fbdev/fsl-diu-fb.c
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@ -360,6 +360,10 @@ struct mfb_info {
* @ad[]: Area Descriptors for each real AOI
* @gamma: gamma color table
* @cursor: hardware cursor data
* @blank_cursor: blank cursor for hiding cursor
* @next_cursor: scratch space to build load cursor
* @edid_data: EDID information buffer
* @has_edid: whether or not the EDID buffer is valid
*
* This data structure must be allocated with 32-byte alignment, so that the
* internal fields can be aligned properly.
@ -381,6 +385,8 @@ struct fsl_diu_data {
__le16 cursor[MAX_CURS * MAX_CURS] __aligned(32);
/* Blank cursor data -- used to hide the cursor */
__le16 blank_cursor[MAX_CURS * MAX_CURS] __aligned(32);
/* Scratch cursor data -- used to build new cursor */
__le16 next_cursor[MAX_CURS * MAX_CURS] __aligned(32);
uint8_t edid_data[EDID_LENGTH];
bool has_edid;
} __aligned(32);
@ -1056,13 +1062,17 @@ static int fsl_diu_cursor(struct fb_info *info, struct fb_cursor *cursor)
* FB_CUR_SETSHAPE - the cursor bitmask has changed
*/
if (cursor->set & (FB_CUR_SETSHAPE | FB_CUR_SETCMAP | FB_CUR_SETIMAGE)) {
/*
* Determine the size of the cursor image data. Normally,
* it's 8x16.
*/
unsigned int image_size =
DIV_ROUND_UP(cursor->image.width, 8) * cursor->image.height;
DIV_ROUND_UP(cursor->image.width, 8) *
cursor->image.height;
unsigned int image_words =
DIV_ROUND_UP(image_size, sizeof(uint32_t));
unsigned int bg_idx = cursor->image.bg_color;
unsigned int fg_idx = cursor->image.fg_color;
uint8_t buffer[image_size];
uint32_t *image, *source, *mask;
uint16_t fg, bg;
unsigned int i;
@ -1070,13 +1080,6 @@ static int fsl_diu_cursor(struct fb_info *info, struct fb_cursor *cursor)
if (info->state != FBINFO_STATE_RUNNING)
return 0;
/*
* Determine the size of the cursor image data. Normally,
* it's 8x16.
*/
image_size = DIV_ROUND_UP(cursor->image.width, 8) *
cursor->image.height;
bg = ((info->cmap.red[bg_idx] & 0xf8) << 7) |
((info->cmap.green[bg_idx] & 0xf8) << 2) |
((info->cmap.blue[bg_idx] & 0xf8) >> 3) |
@ -1088,7 +1091,7 @@ static int fsl_diu_cursor(struct fb_info *info, struct fb_cursor *cursor)
1 << 15;
/* Use 32-bit operations on the data to improve performance */
image = (uint32_t *)buffer;
image = (uint32_t *)data->next_cursor;
source = (uint32_t *)cursor->image.data;
mask = (uint32_t *)cursor->mask;