diff options
| -rw-r--r-- | drivers/gpu/drm/i915/intel_bios.c | 37 | ||||
| -rw-r--r-- | drivers/gpu/drm/i915/intel_bios.h | 6 |
2 files changed, 37 insertions, 6 deletions
diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c index 64e5b15ae0b6..be83b77aa018 100644 --- a/drivers/gpu/drm/i915/intel_bios.c +++ b/drivers/gpu/drm/i915/intel_bios.c @@ -1051,17 +1051,39 @@ parse_device_mapping(struct drm_i915_private *dev_priv, const union child_device_config *p_child; union child_device_config *child_dev_ptr; int i, child_device_num, count; - u16 block_size; + u8 expected_size; + u16 block_size; p_defs = find_section(bdb, BDB_GENERAL_DEFINITIONS); if (!p_defs) { DRM_DEBUG_KMS("No general definition block is found, no devices defined.\n"); return; } - if (p_defs->child_dev_size < sizeof(*p_child)) { - DRM_ERROR("General definiton block child device size is too small.\n"); + if (bdb->version < 195) { + expected_size = sizeof(struct old_child_dev_config); + } else if (bdb->version == 195) { + expected_size = 37; + } else if (bdb->version <= 197) { + expected_size = 38; + } else { + expected_size = 38; + BUILD_BUG_ON(sizeof(*p_child) < 38); + DRM_DEBUG_DRIVER("Expected child device config size for VBT version %u not known; assuming %u\n", + bdb->version, expected_size); + } + + /* The legacy sized child device config is the minimum we need. */ + if (p_defs->child_dev_size < sizeof(struct old_child_dev_config)) { + DRM_ERROR("Child device config size %u is too small.\n", + p_defs->child_dev_size); return; } + + /* Flag an error for unexpected size, but continue anyway. */ + if (p_defs->child_dev_size != expected_size) + DRM_ERROR("Unexpected child device config size %u (expected %u for VBT version %u)\n", + p_defs->child_dev_size, expected_size, bdb->version); + /* get the block size of general definitions */ block_size = get_blocksize(p_defs); /* get the number of child device */ @@ -1106,7 +1128,14 @@ parse_device_mapping(struct drm_i915_private *dev_priv, child_dev_ptr = dev_priv->vbt.child_dev + count; count++; - memcpy(child_dev_ptr, p_child, sizeof(*p_child)); + + /* + * Copy as much as we know (sizeof) and is available + * (child_dev_size) of the child device. Accessing the data must + * depend on VBT version. + */ + memcpy(child_dev_ptr, p_child, + min_t(size_t, p_defs->child_dev_size, sizeof(*p_child))); } return; } diff --git a/drivers/gpu/drm/i915/intel_bios.h b/drivers/gpu/drm/i915/intel_bios.h index 6d909efbf43f..06d0dbde2be6 100644 --- a/drivers/gpu/drm/i915/intel_bios.h +++ b/drivers/gpu/drm/i915/intel_bios.h @@ -203,9 +203,11 @@ struct bdb_general_features { #define DEVICE_PORT_DVOB 0x01 #define DEVICE_PORT_DVOC 0x02 -/* We used to keep this struct but without any version control. We should avoid +/* + * We used to keep this struct but without any version control. We should avoid * using it in the future, but it should be safe to keep using it in the old - * code. */ + * code. Do not change; we rely on its size. + */ struct old_child_dev_config { u16 handle; u16 device_type; |