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drm/i915/bios: Validate fp_timing terminator presence

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Validate the LFP data block a bit hardwer by making sure the
fp_timing terminators (0xffff) are where we expect them to be.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220818192223.29881-2-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
This commit is contained in:
Ville Syrjälä 2022-08-18 22:22:22 +03:00
parent 9aa320341e
commit 4e78d6023c
1 changed files with 32 additions and 28 deletions
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60
drivers/gpu/drm/i915/display/intel_bios.c
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@ -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;
}