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Commit 4a1208c5 authored by Kees Cook's avatar Kees Cook Committed by Bartlomiej Zolnierkiewicz
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video: fbdev: fsl-diu-fb: Remove VLA usage 

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: default avatarKees Cook <keescook@chromium.org>
Acked-by: default avatarTimur Tabi <timur@kernel.org>
Signed-off-by: default avatarBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
parent 31e1391a

drivers/video/fbdev/fsl-diu-fb.c

+13 −10
Original line number Diff line number Diff line
@@ -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;