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drm/i915/bios: Extract vbt_signature[]

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Replace the three hand rolled "$VBT"s with a vbt_signature[]
to avoid accidents.

v2: Include terminating '\0' for safety (Jani)

Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240923152453.11230-6-ville.syrjala@linux.intel.com
This commit is contained in:
Ville Syrjälä 2024-09-23 18:24:52 +03:00
parent 4c997c6e43
commit 0667ca8002
1 changed files with 12 additions and 3 deletions
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15
drivers/gpu/drm/i915/display/intel_bios.c
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@ -2964,6 +2964,9 @@ static const struct bdb_header *get_bdb_header(const struct vbt_header *vbt)
return _vbt + vbt->bdb_offset;
}
static const char vbt_signature[] = "$VBT";
static const int vbt_signature_len = 4;
/**
* intel_bios_is_valid_vbt - does the given buffer contain a valid VBT
* @display: display device
@ -2986,7 +2989,7 @@ bool intel_bios_is_valid_vbt(struct intel_display *display,
return false;
}
if (memcmp(vbt->signature, "$VBT", 4)) {
if (memcmp(vbt->signature, vbt_signature, vbt_signature_len)) {
drm_dbg_kms(display->drm, "VBT invalid signature\n");
return false;
}
@ -3082,9 +3085,12 @@ static struct vbt_header *spi_oprom_get_vbt(struct intel_display *display,
oprom_offset = intel_uncore_read(&i915->uncore, OROM_OFFSET);
oprom_offset &= OROM_OFFSET_MASK;
BUILD_BUG_ON(vbt_signature_len != sizeof(vbt_signature) - 1);
BUILD_BUG_ON(vbt_signature_len != sizeof(u32));
for (count = 0; count < oprom_size; count += 4) {
data = intel_spi_read32(&i915->uncore, oprom_offset + count);
if (data == *((const u32 *)"$VBT")) {
if (data == *((const u32 *)vbt_signature)) {
found = oprom_offset + count;
break;
}
@ -3144,9 +3150,12 @@ static struct vbt_header *oprom_get_vbt(struct intel_display *display,
if (!oprom)
return NULL;
BUILD_BUG_ON(vbt_signature_len != sizeof(vbt_signature) - 1);
BUILD_BUG_ON(vbt_signature_len != sizeof(u32));
/* Scour memory looking for the VBT signature. */
for (i = 0; i + 4 < size; i += 4) {
if (ioread32(oprom + i) != *((const u32 *)"$VBT"))
if (ioread32(oprom + i) != *((const u32 *)vbt_signature))
continue;
p = oprom + i;