From: Ville Syrjälä ville.syrjala@linux.intel.com
Validate the LFP data block a bit hardwer by making sure the fp_timing terminators (0xffff) are where we expect them to be.
Cc: stable@vger.kernel.org # 5.19.x: 39b1bc4b5bcc: drm/i915: Rename block_size()/block_offset() Cc: stable@vger.kernel.org # 5.19+ Signed-off-by: Ville Syrjälä ville.syrjala@linux.intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20220818192223.29881-2-ville.s... Reviewed-by: Jani Nikula jani.nikula@intel.com (cherry picked from commit 4e78d6023c15c6acce8fbe42e13027c460395522) --- drivers/gpu/drm/i915/display/intel_bios.c | 60 ++++++++++++----------- 1 file changed, 32 insertions(+), 28 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c index 7d6eb9ad7a02..1a30e645c5a7 100644 --- a/drivers/gpu/drm/i915/display/intel_bios.c +++ b/drivers/gpu/drm/i915/display/intel_bios.c @@ -135,18 +135,6 @@ static u32 raw_block_offset(const void *bdb, enum bdb_block_id section_id) return block - bdb; }
-/* size of the block excluding the header */ -static u32 raw_block_size(const void *bdb, enum bdb_block_id section_id) -{ - const void *block; - - block = find_raw_section(bdb, section_id); - if (!block) - return 0; - - return get_blocksize(block); -} - struct bdb_block_entry { struct list_head node; enum bdb_block_id section_id; @@ -231,9 +219,14 @@ static bool validate_lfp_data_ptrs(const void *bdb, { int fp_timing_size, dvo_timing_size, panel_pnp_id_size, panel_name_size; int data_block_size, lfp_data_size; + const void *data_block; int i;
- data_block_size = raw_block_size(bdb, BDB_LVDS_LFP_DATA); + data_block = find_raw_section(bdb, BDB_LVDS_LFP_DATA); + if (!data_block) + return false; + + data_block_size = get_blocksize(data_block); if (data_block_size == 0) return false;
@@ -261,21 +254,6 @@ static bool validate_lfp_data_ptrs(const void *bdb, if (16 * lfp_data_size > data_block_size) return false;
- /* - * Except for vlv/chv machines all real VBTs seem to have 6 - * unaccounted bytes in the fp_timing table. And it doesn't - * appear to be a really intentional hole as the fp_timing - * 0xffff terminator is always within those 6 missing bytes. - */ - if (fp_timing_size + dvo_timing_size + panel_pnp_id_size != lfp_data_size && - fp_timing_size + 6 + dvo_timing_size + panel_pnp_id_size != lfp_data_size) - return false; - - if (ptrs->ptr[0].fp_timing.offset + fp_timing_size > ptrs->ptr[0].dvo_timing.offset || - ptrs->ptr[0].dvo_timing.offset + dvo_timing_size != ptrs->ptr[0].panel_pnp_id.offset || - ptrs->ptr[0].panel_pnp_id.offset + panel_pnp_id_size != lfp_data_size) - return false; - /* make sure the table entries have uniform size */ for (i = 1; i < 16; i++) { if (ptrs->ptr[i].fp_timing.table_size != fp_timing_size || @@ -289,6 +267,23 @@ static bool validate_lfp_data_ptrs(const void *bdb, return false; }
+ /* + * Except for vlv/chv machines all real VBTs seem to have 6 + * unaccounted bytes in the fp_timing table. And it doesn't + * appear to be a really intentional hole as the fp_timing + * 0xffff terminator is always within those 6 missing bytes. + */ + if (fp_timing_size + 6 + dvo_timing_size + panel_pnp_id_size == lfp_data_size) + fp_timing_size += 6; + + if (fp_timing_size + dvo_timing_size + panel_pnp_id_size != lfp_data_size) + return false; + + if (ptrs->ptr[0].fp_timing.offset + fp_timing_size != ptrs->ptr[0].dvo_timing.offset || + ptrs->ptr[0].dvo_timing.offset + dvo_timing_size != ptrs->ptr[0].panel_pnp_id.offset || + ptrs->ptr[0].panel_pnp_id.offset + panel_pnp_id_size != lfp_data_size) + return false; + /* make sure the tables fit inside the data block */ for (i = 0; i < 16; i++) { if (ptrs->ptr[i].fp_timing.offset + fp_timing_size > data_block_size || @@ -300,6 +295,15 @@ static bool validate_lfp_data_ptrs(const void *bdb, if (ptrs->panel_name.offset + 16 * panel_name_size > data_block_size) return false;
+ /* make sure fp_timing terminators are present at expected locations */ + for (i = 0; i < 16; i++) { + const u16 *t = data_block + ptrs->ptr[i].fp_timing.offset + + fp_timing_size - 2; + + if (*t != 0xffff) + return false; + } + return true; }