Commit f0067a31 authored by Jani Nikula's avatar Jani Nikula

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
......@@ -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
......
......@@ -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")) {
/*
* 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.
*/
void *_bios = (void __force *) bios;
void *vbt;
vbt = validate_vbt(_bios, size, _bios + i);
break;
}
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.
*/
vbt = (void __force *) bios + i;
if (intel_bios_is_valid_vbt(vbt, size - i))
return vbt;
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);
......
......@@ -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;
......
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