Commit 0667ca80 authored by Ville Syrjälä's avatar Ville Syrjälä
Browse files

drm/i915/bios: Extract vbt_signature[] 



Replace the three hand rolled "$VBT"s with a vbt_signature[]
to avoid accidents.

v2: Include terminating '\0' for safety (Jani)

Reviewed-by: default avatarJani Nikula <jani.nikula@intel.com>
Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240923152453.11230-6-ville.syrjala@linux.intel.com
parent 4c997c6e

drivers/gpu/drm/i915/display/intel_bios.c

+12 −3
Original line number Diff line number Diff line
@@ -2964,6 +2964,9 @@ static const struct bdb_header *get_bdb_header(const struct vbt_header *vbt) 
	return _vbt + vbt->bdb_offset;

}



static const char vbt_signature[] = "$VBT";

static const int vbt_signature_len = 4;



/**

 * intel_bios_is_valid_vbt - does the given buffer contain a valid VBT

 * @display:	display device
@@ -2986,7 +2989,7 @@ bool intel_bios_is_valid_vbt(struct intel_display *display, 
		return false;

	}



	if (memcmp(vbt->signature, "$VBT", 4)) {

	if (memcmp(vbt->signature, vbt_signature, vbt_signature_len)) {

		drm_dbg_kms(display->drm, "VBT invalid signature\n");

		return false;

	}
@@ -3082,9 +3085,12 @@ static struct vbt_header *spi_oprom_get_vbt(struct intel_display *display, 
	oprom_offset = intel_uncore_read(&i915->uncore, OROM_OFFSET);

	oprom_offset &= OROM_OFFSET_MASK;



	BUILD_BUG_ON(vbt_signature_len != sizeof(vbt_signature) - 1);

	BUILD_BUG_ON(vbt_signature_len != sizeof(u32));



	for (count = 0; count < oprom_size; count += 4) {

		data = intel_spi_read32(&i915->uncore, oprom_offset + count);

		if (data == *((const u32 *)"$VBT")) {

		if (data == *((const u32 *)vbt_signature)) {

			found = oprom_offset + count;

			break;

		}
@@ -3144,9 +3150,12 @@ static struct vbt_header *oprom_get_vbt(struct intel_display *display, 
	if (!oprom)

		return NULL;



	BUILD_BUG_ON(vbt_signature_len != sizeof(vbt_signature) - 1);

	BUILD_BUG_ON(vbt_signature_len != sizeof(u32));



	/* Scour memory looking for the VBT signature. */

	for (i = 0; i + 4 < size; i += 4) {

		if (ioread32(oprom + i) != *((const u32 *)"$VBT"))

		if (ioread32(oprom + i) != *((const u32 *)vbt_signature))

			continue;



		p = oprom + i;