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Commit f0067a31 authored by Jani Nikula's avatar Jani Nikula
Browse files

drm/i915: refactor VBT validation 



Make the validation function a boolean operating on a buffer of given
size, removing the extra pointer dances.

Move the OpRegion based VBT validation to intel_opregion_setup(), only
initializing opregion->vbt if it's valid.

v2: move logging about valid VBT to opregion setup too (Ville)

Reviewed-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1450178175-27420-1-git-send-email-jani.nikula@intel.com
parent 8b8e1a89

drivers/gpu/drm/i915/i915_drv.h

+1 −0
Original line number Diff line number Diff line
@@ -3354,6 +3354,7 @@ extern void intel_i2c_reset(struct drm_device *dev); 


/* intel_bios.c */

int intel_bios_init(struct drm_device *dev);

bool intel_bios_is_valid_vbt(const void *buf, size_t size);



/* intel_opregion.c */

#ifdef CONFIG_ACPI

drivers/gpu/drm/i915/intel_bios.c

+33 −34
Original line number Diff line number Diff line
@@ -1221,37 +1221,40 @@ static const struct bdb_header *get_bdb_header(const struct vbt_header *vbt) 
	return _vbt + vbt->bdb_offset;

}



static const struct vbt_header *validate_vbt(const void *base,

					     size_t size,

					     const void *_vbt)

/**

 * intel_bios_is_valid_vbt - does the given buffer contain a valid VBT

 * @buf:	pointer to a buffer to validate

 * @size:	size of the buffer

 *

 * Returns true on valid VBT.

 */

bool intel_bios_is_valid_vbt(const void *buf, size_t size)

{

	size_t offset = _vbt - base;

	const struct vbt_header *vbt = _vbt;

	const struct vbt_header *vbt = buf;

	const struct bdb_header *bdb;



	if (!vbt)

		return NULL;

		return false;



	if (offset + sizeof(struct vbt_header) > size) {

	if (sizeof(struct vbt_header) > size) {

		DRM_DEBUG_DRIVER("VBT header incomplete\n");

		return NULL;

		return false;

	}



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

		DRM_DEBUG_DRIVER("VBT invalid signature\n");

		return NULL;

		return false;

	}



	offset += vbt->bdb_offset;

	if (offset + sizeof(struct bdb_header) > size) {

	if (vbt->bdb_offset + sizeof(struct bdb_header) > size) {

		DRM_DEBUG_DRIVER("BDB header incomplete\n");

		return NULL;

		return false;

	}



	bdb = get_bdb_header(vbt);

	if (offset + bdb->bdb_size > size) {

	if (vbt->bdb_offset + bdb->bdb_size > size) {

		DRM_DEBUG_DRIVER("BDB incomplete\n");

		return NULL;

		return false;

	}



	return vbt;
@@ -1259,26 +1262,27 @@ static const struct vbt_header *validate_vbt(const void *base, 


static const struct vbt_header *find_vbt(void __iomem *bios, size_t size)

{

	const struct vbt_header *vbt = NULL;

	size_t i;



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

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

		if (ioread32(bios + i) == *((const u32 *) "$VBT")) {

		void *vbt;



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

			continue;



		/*

			 * This is the one place where we explicitly discard the

			 * address space (__iomem) of the BIOS/VBT. From now on

			 * everything is based on 'base', and treated as regular

			 * memory.

		 * This is the one place where we explicitly discard the address

		 * space (__iomem) of the BIOS/VBT.

		 */

			void *_bios = (void __force *) bios;

		vbt = (void __force *) bios + i;

		if (intel_bios_is_valid_vbt(vbt, size - i))

			return vbt;



			vbt = validate_vbt(_bios, size, _bios + i);

		break;

	}

	}



	return vbt;

	return NULL;

}



/**
@@ -1295,7 +1299,7 @@ intel_bios_init(struct drm_device *dev) 
{

	struct drm_i915_private *dev_priv = dev->dev_private;

	struct pci_dev *pdev = dev->pdev;

	const struct vbt_header *vbt;

	const struct vbt_header *vbt = dev_priv->opregion.vbt;

	const struct bdb_header *bdb;

	u8 __iomem *bios = NULL;
@@ -1304,12 +1308,7 @@ intel_bios_init(struct drm_device *dev) 


	init_vbt_defaults(dev_priv);



	/* XXX Should this validation be moved to intel_opregion.c? */

	vbt = validate_vbt(dev_priv->opregion.header, OPREGION_SIZE,

			   dev_priv->opregion.vbt);

	if (vbt) {

		DRM_DEBUG_KMS("Found valid VBT in ACPI OpRegion\n");

	} else {

	if (!vbt) {

		size_t size;



		bios = pci_map_rom(pdev, &size);

drivers/gpu/drm/i915/intel_opregion.c

+9 −2
Original line number Diff line number Diff line
@@ -986,8 +986,15 @@ int intel_opregion_setup(struct drm_device *dev) 
	if (mboxes & MBOX_ASLE_EXT)

		DRM_DEBUG_DRIVER("ASLE extension supported\n");



	if (!dmi_check_system(intel_no_opregion_vbt))

		opregion->vbt = base + OPREGION_VBT_OFFSET;

	if (!dmi_check_system(intel_no_opregion_vbt)) {

		void *vbt = base + OPREGION_VBT_OFFSET;

		u32 vbt_size = OPREGION_SIZE - OPREGION_VBT_OFFSET;



		if (intel_bios_is_valid_vbt(vbt, vbt_size)) {

			DRM_DEBUG_KMS("Found valid VBT in ACPI OpRegion\n");

			opregion->vbt = vbt;

		}

	}



	return 0;