[Intel-gfx] [PATCH v3 02/22] drm/i915/bios: Make copies of VBT data blocks

Jani Nikula jani.nikula at linux.intel.com
Thu Apr 7 10:23:38 UTC 2022


On Wed, 06 Apr 2022, Ville Syrjala <ville.syrjala at linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
> Make a copy of each VB data block with a guaranteed minimum
> size. The extra (if any) will just be left zeroed.
>
> This means we don't have to worry about going out of bounds
> when accessing any of the structure members. Otherwise that
> could easliy happen if we simply get the version check wrong,
> or if the VBT is broken/malicious.
>
> v2: Don't do arithmetic between bdb header and copy
>     of the LFP data block (Jani)
> v3: Make all the copies up front
> v4: Only WARN about min_size==0 if we found the block
>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_bios.c | 230 ++++++++++++++++------
>  drivers/gpu/drm/i915/i915_drv.h           |   1 +
>  2 files changed, 174 insertions(+), 57 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
> index 5518f4cfa1b1..068978734e3b 100644
> --- a/drivers/gpu/drm/i915/display/intel_bios.c
> +++ b/drivers/gpu/drm/i915/display/intel_bios.c
> @@ -88,7 +88,7 @@ static u32 get_blocksize(const void *block_data)
>  }
>  
>  static const void *
> -find_section(const void *_bdb, enum bdb_block_id section_id)
> +find_raw_section(const void *_bdb, enum bdb_block_id section_id)
>  {
>  	const struct bdb_header *bdb = _bdb;
>  	const u8 *base = _bdb;
> @@ -118,6 +118,124 @@ find_section(const void *_bdb, enum bdb_block_id section_id)
>  	return NULL;
>  }
>  
> +/*
> + * Offset from the start of BDB to the start of the
> + * block data (just past the block header).
> + */
> +static u32 block_offset(const void *bdb, enum bdb_block_id section_id)
> +{
> +	const void *block;
> +
> +	block = find_raw_section(bdb, section_id);
> +	if (!block)
> +		return 0;
> +
> +	return block - bdb;
> +}
> +
> +struct bdb_block_entry {
> +	struct list_head node;
> +	enum bdb_block_id section_id;
> +	u8 data[];
> +};
> +
> +static const void *
> +find_section(struct drm_i915_private *i915,
> +	     enum bdb_block_id section_id)
> +{
> +	struct bdb_block_entry *entry;
> +
> +	list_for_each_entry(entry, &i915->vbt.bdb_blocks, node) {
> +		if (entry->section_id == section_id)
> +			return entry->data + 3;
> +	}
> +

Failing to find the section_id in the list above, perhaps this should
check if the section_id is present in bdb_blocks[] and complain
loudly. If we fail to add a section there, this will never find
it. I.e. we should never call find_section() on a section_id that isn't
present in bdb_blocks[].

I also dislike the +/- 3 here and there.

But both of these can be cleaned up later.

Reviewed-by: Jani Nikula <jani.nikula at intel.com>


> +	return NULL;
> +}
> +
> +static const struct {
> +	enum bdb_block_id section_id;
> +	size_t min_size;
> +} bdb_blocks[] = {
> +	{ .section_id = BDB_GENERAL_FEATURES,
> +	  .min_size = sizeof(struct bdb_general_features), },
> +	{ .section_id = BDB_GENERAL_DEFINITIONS,
> +	  .min_size = sizeof(struct bdb_general_definitions), },
> +	{ .section_id = BDB_PSR,
> +	  .min_size = sizeof(struct bdb_psr), },
> +	{ .section_id = BDB_DRIVER_FEATURES,
> +	  .min_size = sizeof(struct bdb_driver_features), },
> +	{ .section_id = BDB_SDVO_LVDS_OPTIONS,
> +	  .min_size = sizeof(struct bdb_sdvo_lvds_options), },
> +	{ .section_id = BDB_SDVO_PANEL_DTDS,
> +	  .min_size = sizeof(struct bdb_sdvo_panel_dtds), },
> +	{ .section_id = BDB_EDP,
> +	  .min_size = sizeof(struct bdb_edp), },
> +	{ .section_id = BDB_LVDS_OPTIONS,
> +	  .min_size = sizeof(struct bdb_lvds_options), },
> +	{ .section_id = BDB_LVDS_LFP_DATA_PTRS,
> +	  .min_size = sizeof(struct bdb_lvds_lfp_data_ptrs), },
> +	{ .section_id = BDB_LVDS_LFP_DATA,
> +	  .min_size = sizeof(struct bdb_lvds_lfp_data), },
> +	{ .section_id = BDB_LVDS_BACKLIGHT,
> +	  .min_size = sizeof(struct bdb_lfp_backlight_data), },
> +	{ .section_id = BDB_LFP_POWER,
> +	  .min_size = sizeof(struct bdb_lfp_power), },
> +	{ .section_id = BDB_MIPI_CONFIG,
> +	  .min_size = sizeof(struct bdb_mipi_config), },
> +	{ .section_id = BDB_MIPI_SEQUENCE,
> +	  .min_size = sizeof(struct bdb_mipi_sequence) },
> +	{ .section_id = BDB_COMPRESSION_PARAMETERS,
> +	  .min_size = sizeof(struct bdb_compression_parameters), },
> +	{ .section_id = BDB_GENERIC_DTD,
> +	  .min_size = sizeof(struct bdb_generic_dtd), },
> +};
> +
> +static void
> +init_bdb_block(struct drm_i915_private *i915,
> +	       const void *bdb, enum bdb_block_id section_id,
> +	       size_t min_size)
> +{
> +	struct bdb_block_entry *entry;
> +	const void *block;
> +	size_t block_size;
> +
> +	block = find_raw_section(bdb, section_id);
> +	if (!block)
> +		return;
> +
> +	drm_WARN(&i915->drm, min_size == 0,
> +		 "Block %d min_size is zero\n", section_id);
> +
> +	block_size = get_blocksize(block);
> +
> +	entry = kzalloc(struct_size(entry, data, max(min_size, block_size) + 3),
> +			GFP_KERNEL);
> +	if (!entry)
> +		return;
> +
> +	entry->section_id = section_id;
> +	memcpy(entry->data, block - 3, block_size + 3);
> +
> +	drm_dbg_kms(&i915->drm, "Found BDB block %d (size %zu, min size %zu)\n",
> +		    section_id, block_size, min_size);
> +
> +	list_add_tail(&entry->node, &i915->vbt.bdb_blocks);
> +}
> +
> +static void init_bdb_blocks(struct drm_i915_private *i915,
> +			    const void *bdb)
> +{
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(bdb_blocks); i++) {
> +		enum bdb_block_id section_id = bdb_blocks[i].section_id;
> +		size_t min_size = bdb_blocks[i].min_size;
> +
> +		init_bdb_block(i915, bdb, section_id, min_size);
> +	}
> +}
> +
>  static void
>  fill_detail_timing_data(struct drm_display_mode *panel_fixed_mode,
>  			const struct lvds_dvo_timing *dvo_timing)
> @@ -199,7 +317,7 @@ get_lvds_fp_timing(const struct bdb_header *bdb,
>  		   const struct bdb_lvds_lfp_data_ptrs *ptrs,
>  		   int index)
>  {
> -	size_t data_ofs = (const u8 *)data - (const u8 *)bdb;
> +	size_t data_ofs = block_offset(bdb, BDB_LVDS_LFP_DATA);
>  	u16 data_size = ((const u16 *)data)[-1]; /* stored in header */
>  	size_t ofs;
>  
> @@ -214,15 +332,14 @@ get_lvds_fp_timing(const struct bdb_header *bdb,
>  
>  /* Parse general panel options */
>  static void
> -parse_panel_options(struct drm_i915_private *i915,
> -		    const struct bdb_header *bdb)
> +parse_panel_options(struct drm_i915_private *i915)
>  {
>  	const struct bdb_lvds_options *lvds_options;
>  	int panel_type;
>  	int drrs_mode;
>  	int ret;
>  
> -	lvds_options = find_section(bdb, BDB_LVDS_OPTIONS);
> +	lvds_options = find_section(i915, BDB_LVDS_OPTIONS);
>  	if (!lvds_options)
>  		return;
>  
> @@ -285,11 +402,11 @@ parse_lfp_panel_dtd(struct drm_i915_private *i915,
>  	struct drm_display_mode *panel_fixed_mode;
>  	int panel_type = i915->vbt.panel_type;
>  
> -	lvds_lfp_data = find_section(bdb, BDB_LVDS_LFP_DATA);
> +	lvds_lfp_data = find_section(i915, BDB_LVDS_LFP_DATA);
>  	if (!lvds_lfp_data)
>  		return;
>  
> -	lvds_lfp_data_ptrs = find_section(bdb, BDB_LVDS_LFP_DATA_PTRS);
> +	lvds_lfp_data_ptrs = find_section(i915, BDB_LVDS_LFP_DATA_PTRS);
>  	if (!lvds_lfp_data_ptrs)
>  		return;
>  
> @@ -325,15 +442,14 @@ parse_lfp_panel_dtd(struct drm_i915_private *i915,
>  }
>  
>  static void
> -parse_generic_dtd(struct drm_i915_private *i915,
> -		  const struct bdb_header *bdb)
> +parse_generic_dtd(struct drm_i915_private *i915)
>  {
>  	const struct bdb_generic_dtd *generic_dtd;
>  	const struct generic_dtd_entry *dtd;
>  	struct drm_display_mode *panel_fixed_mode;
>  	int num_dtd;
>  
> -	generic_dtd = find_section(bdb, BDB_GENERIC_DTD);
> +	generic_dtd = find_section(i915, BDB_GENERIC_DTD);
>  	if (!generic_dtd)
>  		return;
>  
> @@ -416,21 +532,20 @@ parse_panel_dtd(struct drm_i915_private *i915,
>  	 * back to trying the old LFP block if that fails.
>  	 */
>  	if (i915->vbt.version >= 229)
> -		parse_generic_dtd(i915, bdb);
> +		parse_generic_dtd(i915);
>  	if (!i915->vbt.lfp_lvds_vbt_mode)
>  		parse_lfp_panel_dtd(i915, bdb);
>  }
>  
>  static void
> -parse_lfp_backlight(struct drm_i915_private *i915,
> -		    const struct bdb_header *bdb)
> +parse_lfp_backlight(struct drm_i915_private *i915)
>  {
>  	const struct bdb_lfp_backlight_data *backlight_data;
>  	const struct lfp_backlight_data_entry *entry;
>  	int panel_type = i915->vbt.panel_type;
>  	u16 level;
>  
> -	backlight_data = find_section(bdb, BDB_LVDS_BACKLIGHT);
> +	backlight_data = find_section(i915, BDB_LVDS_BACKLIGHT);
>  	if (!backlight_data)
>  		return;
>  
> @@ -514,8 +629,7 @@ parse_lfp_backlight(struct drm_i915_private *i915,
>  
>  /* Try to find sdvo panel data */
>  static void
> -parse_sdvo_panel_data(struct drm_i915_private *i915,
> -		      const struct bdb_header *bdb)
> +parse_sdvo_panel_data(struct drm_i915_private *i915)
>  {
>  	const struct bdb_sdvo_panel_dtds *dtds;
>  	struct drm_display_mode *panel_fixed_mode;
> @@ -531,14 +645,14 @@ parse_sdvo_panel_data(struct drm_i915_private *i915,
>  	if (index == -1) {
>  		const struct bdb_sdvo_lvds_options *sdvo_lvds_options;
>  
> -		sdvo_lvds_options = find_section(bdb, BDB_SDVO_LVDS_OPTIONS);
> +		sdvo_lvds_options = find_section(i915, BDB_SDVO_LVDS_OPTIONS);
>  		if (!sdvo_lvds_options)
>  			return;
>  
>  		index = sdvo_lvds_options->panel_type;
>  	}
>  
> -	dtds = find_section(bdb, BDB_SDVO_PANEL_DTDS);
> +	dtds = find_section(i915, BDB_SDVO_PANEL_DTDS);
>  	if (!dtds)
>  		return;
>  
> @@ -570,12 +684,11 @@ static int intel_bios_ssc_frequency(struct drm_i915_private *i915,
>  }
>  
>  static void
> -parse_general_features(struct drm_i915_private *i915,
> -		       const struct bdb_header *bdb)
> +parse_general_features(struct drm_i915_private *i915)
>  {
>  	const struct bdb_general_features *general;
>  
> -	general = find_section(bdb, BDB_GENERAL_FEATURES);
> +	general = find_section(i915, BDB_GENERAL_FEATURES);
>  	if (!general)
>  		return;
>  
> @@ -695,12 +808,11 @@ parse_sdvo_device_mapping(struct drm_i915_private *i915)
>  }
>  
>  static void
> -parse_driver_features(struct drm_i915_private *i915,
> -		      const struct bdb_header *bdb)
> +parse_driver_features(struct drm_i915_private *i915)
>  {
>  	const struct bdb_driver_features *driver;
>  
> -	driver = find_section(bdb, BDB_DRIVER_FEATURES);
> +	driver = find_section(i915, BDB_DRIVER_FEATURES);
>  	if (!driver)
>  		return;
>  
> @@ -747,8 +859,7 @@ parse_driver_features(struct drm_i915_private *i915,
>  }
>  
>  static void
> -parse_power_conservation_features(struct drm_i915_private *i915,
> -				  const struct bdb_header *bdb)
> +parse_power_conservation_features(struct drm_i915_private *i915)
>  {
>  	const struct bdb_lfp_power *power;
>  	u8 panel_type = i915->vbt.panel_type;
> @@ -756,7 +867,7 @@ parse_power_conservation_features(struct drm_i915_private *i915,
>  	if (i915->vbt.version < 228)
>  		return;
>  
> -	power = find_section(bdb, BDB_LFP_POWER);
> +	power = find_section(i915, BDB_LFP_POWER);
>  	if (!power)
>  		return;
>  
> @@ -776,14 +887,14 @@ parse_power_conservation_features(struct drm_i915_private *i915,
>  }
>  
>  static void
> -parse_edp(struct drm_i915_private *i915, const struct bdb_header *bdb)
> +parse_edp(struct drm_i915_private *i915)
>  {
>  	const struct bdb_edp *edp;
>  	const struct edp_power_seq *edp_pps;
>  	const struct edp_fast_link_params *edp_link_params;
>  	int panel_type = i915->vbt.panel_type;
>  
> -	edp = find_section(bdb, BDB_EDP);
> +	edp = find_section(i915, BDB_EDP);
>  	if (!edp)
>  		return;
>  
> @@ -894,13 +1005,13 @@ parse_edp(struct drm_i915_private *i915, const struct bdb_header *bdb)
>  }
>  
>  static void
> -parse_psr(struct drm_i915_private *i915, const struct bdb_header *bdb)
> +parse_psr(struct drm_i915_private *i915)
>  {
>  	const struct bdb_psr *psr;
>  	const struct psr_table *psr_table;
>  	int panel_type = i915->vbt.panel_type;
>  
> -	psr = find_section(bdb, BDB_PSR);
> +	psr = find_section(i915, BDB_PSR);
>  	if (!psr) {
>  		drm_dbg_kms(&i915->drm, "No PSR BDB found.\n");
>  		return;
> @@ -1034,8 +1145,7 @@ static void parse_dsi_backlight_ports(struct drm_i915_private *i915,
>  }
>  
>  static void
> -parse_mipi_config(struct drm_i915_private *i915,
> -		  const struct bdb_header *bdb)
> +parse_mipi_config(struct drm_i915_private *i915)
>  {
>  	const struct bdb_mipi_config *start;
>  	const struct mipi_config *config;
> @@ -1058,7 +1168,7 @@ parse_mipi_config(struct drm_i915_private *i915,
>  	/* Parse #52 for panel index used from panel_type already
>  	 * parsed
>  	 */
> -	start = find_section(bdb, BDB_MIPI_CONFIG);
> +	start = find_section(i915, BDB_MIPI_CONFIG);
>  	if (!start) {
>  		drm_dbg_kms(&i915->drm, "No MIPI config BDB found");
>  		return;
> @@ -1354,8 +1464,7 @@ static void fixup_mipi_sequences(struct drm_i915_private *i915)
>  }
>  
>  static void
> -parse_mipi_sequence(struct drm_i915_private *i915,
> -		    const struct bdb_header *bdb)
> +parse_mipi_sequence(struct drm_i915_private *i915)
>  {
>  	int panel_type = i915->vbt.panel_type;
>  	const struct bdb_mipi_sequence *sequence;
> @@ -1368,7 +1477,7 @@ parse_mipi_sequence(struct drm_i915_private *i915,
>  	if (i915->vbt.dsi.panel_id != MIPI_DSI_GENERIC_PANEL_ID)
>  		return;
>  
> -	sequence = find_section(bdb, BDB_MIPI_SEQUENCE);
> +	sequence = find_section(i915, BDB_MIPI_SEQUENCE);
>  	if (!sequence) {
>  		drm_dbg_kms(&i915->drm,
>  			    "No MIPI Sequence found, parsing complete\n");
> @@ -1439,8 +1548,7 @@ parse_mipi_sequence(struct drm_i915_private *i915,
>  }
>  
>  static void
> -parse_compression_parameters(struct drm_i915_private *i915,
> -			     const struct bdb_header *bdb)
> +parse_compression_parameters(struct drm_i915_private *i915)
>  {
>  	const struct bdb_compression_parameters *params;
>  	struct intel_bios_encoder_data *devdata;
> @@ -1451,7 +1559,7 @@ parse_compression_parameters(struct drm_i915_private *i915,
>  	if (i915->vbt.version < 198)
>  		return;
>  
> -	params = find_section(bdb, BDB_COMPRESSION_PARAMETERS);
> +	params = find_section(i915, BDB_COMPRESSION_PARAMETERS);
>  	if (params) {
>  		/* Sanity checks */
>  		if (params->entry_size != sizeof(params->data[0])) {
> @@ -2086,8 +2194,7 @@ static void parse_ddi_ports(struct drm_i915_private *i915)
>  }
>  
>  static void
> -parse_general_definitions(struct drm_i915_private *i915,
> -			  const struct bdb_header *bdb)
> +parse_general_definitions(struct drm_i915_private *i915)
>  {
>  	const struct bdb_general_definitions *defs;
>  	struct intel_bios_encoder_data *devdata;
> @@ -2097,7 +2204,7 @@ parse_general_definitions(struct drm_i915_private *i915,
>  	u16 block_size;
>  	int bus_pin;
>  
> -	defs = find_section(bdb, BDB_GENERAL_DEFINITIONS);
> +	defs = find_section(i915, BDB_GENERAL_DEFINITIONS);
>  	if (!defs) {
>  		drm_dbg_kms(&i915->drm,
>  			    "No general definition block is found, no devices defined.\n");
> @@ -2466,6 +2573,7 @@ void intel_bios_init(struct drm_i915_private *i915)
>  	const struct bdb_header *bdb;
>  
>  	INIT_LIST_HEAD(&i915->vbt.display_devices);
> +	INIT_LIST_HEAD(&i915->vbt.bdb_blocks);
>  
>  	if (!HAS_DISPLAY(i915)) {
>  		drm_dbg_kms(&i915->drm,
> @@ -2499,22 +2607,24 @@ void intel_bios_init(struct drm_i915_private *i915)
>  		    "VBT signature \"%.*s\", BDB version %d\n",
>  		    (int)sizeof(vbt->signature), vbt->signature, i915->vbt.version);
>  
> +	init_bdb_blocks(i915, bdb);
> +
>  	/* Grab useful general definitions */
> -	parse_general_features(i915, bdb);
> -	parse_general_definitions(i915, bdb);
> -	parse_panel_options(i915, bdb);
> +	parse_general_features(i915);
> +	parse_general_definitions(i915);
> +	parse_panel_options(i915);
>  	parse_panel_dtd(i915, bdb);
> -	parse_lfp_backlight(i915, bdb);
> -	parse_sdvo_panel_data(i915, bdb);
> -	parse_driver_features(i915, bdb);
> -	parse_power_conservation_features(i915, bdb);
> -	parse_edp(i915, bdb);
> -	parse_psr(i915, bdb);
> -	parse_mipi_config(i915, bdb);
> -	parse_mipi_sequence(i915, bdb);
> +	parse_lfp_backlight(i915);
> +	parse_sdvo_panel_data(i915);
> +	parse_driver_features(i915);
> +	parse_power_conservation_features(i915);
> +	parse_edp(i915);
> +	parse_psr(i915);
> +	parse_mipi_config(i915);
> +	parse_mipi_sequence(i915);
>  
>  	/* Depends on child device list */
> -	parse_compression_parameters(i915, bdb);
> +	parse_compression_parameters(i915);
>  
>  out:
>  	if (!vbt) {
> @@ -2536,14 +2646,20 @@ void intel_bios_init(struct drm_i915_private *i915)
>   */
>  void intel_bios_driver_remove(struct drm_i915_private *i915)
>  {
> -	struct intel_bios_encoder_data *devdata, *n;
> +	struct intel_bios_encoder_data *devdata, *nd;
> +	struct bdb_block_entry *entry, *ne;
>  
> -	list_for_each_entry_safe(devdata, n, &i915->vbt.display_devices, node) {
> +	list_for_each_entry_safe(devdata, nd, &i915->vbt.display_devices, node) {
>  		list_del(&devdata->node);
>  		kfree(devdata->dsc);
>  		kfree(devdata);
>  	}
>  
> +	list_for_each_entry_safe(entry, ne, &i915->vbt.bdb_blocks, node) {
> +		list_del(&entry->node);
> +		kfree(entry);
> +	}
> +
>  	kfree(i915->vbt.sdvo_lvds_vbt_mode);
>  	i915->vbt.sdvo_lvds_vbt_mode = NULL;
>  	kfree(i915->vbt.lfp_lvds_vbt_mode);
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 06e7c2802c5e..9274417cd87a 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -380,6 +380,7 @@ struct intel_vbt_data {
>  	int crt_ddc_pin;
>  
>  	struct list_head display_devices;
> +	struct list_head bdb_blocks;
>  
>  	struct intel_bios_encoder_data *ports[I915_MAX_PORTS]; /* Non-NULL if port present. */
>  	struct sdvo_device_mapping sdvo_mappings[2];

-- 
Jani Nikula, Intel Open Source Graphics Center


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