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: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1450178175-27420-1-git-send-email-jani.nikula@intel.com
diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index 04fb9de..dc3a0fb 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -1221,37 +1221,40 @@
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, "$VBT", 4)) {
DRM_DEBUG_DRIVER("VBT invalid signature\n");
- return NULL;
+ return false;
}
- offset += vbt->bdb_offset;
- if (offset + sizeof(struct bdb_header) > size) {
+ if (vbt->bdb_offset + sizeof(struct bdb_header) > size) {
DRM_DEBUG_DRIVER("BDB header incomplete\n");
- return NULL;
+ return false;
}
bdb = get_bdb_header(vbt);
- if (offset + bdb->bdb_size > size) {
+ if (vbt->bdb_offset + bdb->bdb_size > size) {
DRM_DEBUG_DRIVER("BDB incomplete\n");
- return NULL;
+ return false;
}
return vbt;
@@ -1259,26 +1262,27 @@
static const struct vbt_header *find_vbt(void __iomem *bios, size_t size)
{
- const struct vbt_header *vbt = NULL;
size_t i;
/* Scour memory looking for the VBT signature. */
for (i = 0; i + 4 < size; i++) {
- if (ioread32(bios + i) == *((const u32 *) "$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 @@
{
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 @@
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);