On Tue, 10 Sep 2024, Ville Syrjala <[email protected]> wrote: > From: Ville Syrjälä <[email protected]> > > Replace the three hand rolled "$VBT"s with a vbt_signature[] > to avoid accidents. > > Signed-off-by: Ville Syrjälä <[email protected]> > --- > drivers/gpu/drm/i915/display/intel_bios.c | 12 +++++++++--- > 1 file changed, 9 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_bios.c > b/drivers/gpu/drm/i915/display/intel_bios.c > index cbbda94c3dab..0b92b494117f 100644 > --- a/drivers/gpu/drm/i915/display/intel_bios.c > +++ b/drivers/gpu/drm/i915/display/intel_bios.c > @@ -2964,6 +2964,8 @@ static const struct bdb_header *get_bdb_header(const > struct vbt_header *vbt) > return _vbt + vbt->bdb_offset; > } > > +static const char vbt_signature[4] = "$VBT";
Always a bit scary to add strings without termination, but I guess it's justified here. Reviewed-by: Jani Nikula <[email protected]> > + > /** > * intel_bios_is_valid_vbt - does the given buffer contain a valid VBT > * @display: display device > @@ -2986,7 +2988,7 @@ bool intel_bios_is_valid_vbt(struct intel_display > *display, > return false; > } > > - if (memcmp(vbt->signature, "$VBT", 4)) { > + if (memcmp(vbt->signature, vbt_signature, sizeof(vbt_signature))) { > drm_dbg_kms(display->drm, "VBT invalid signature\n"); > return false; > } > @@ -3082,9 +3084,11 @@ static struct vbt_header *spi_oprom_get_vbt(struct > intel_display *display, > oprom_offset = intel_uncore_read(&i915->uncore, OROM_OFFSET); > oprom_offset &= OROM_OFFSET_MASK; > > + BUILD_BUG_ON(sizeof(vbt_signature) != sizeof(u32)); > + > for (count = 0; count < oprom_size; count += 4) { > data = intel_spi_read32(&i915->uncore, oprom_offset + count); > - if (data == *((const u32 *)"$VBT")) { > + if (data == *((const u32 *)vbt_signature)) { > found = oprom_offset + count; > break; > } > @@ -3144,9 +3148,11 @@ static struct vbt_header *oprom_get_vbt(struct > intel_display *display, > if (!oprom) > return NULL; > > + BUILD_BUG_ON(sizeof(vbt_signature) != 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; -- Jani Nikula, Intel
