| Message ID | 20240910134219.28479-5-ville.syrjala@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/i915/bios: Refactor ROM access | expand |
On Tue, 10 Sep 2024, Ville Syrjala <ville.syrjala@linux.intel.com> wrote: > From: Ville Syrjälä <ville.syrjala@linux.intel.com> > > Replace the three hand rolled "$VBT"s with a vbt_signature[] > to avoid accidents. > > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > --- > drivers/gpu/drm/i915/display/intel_bios.c | 12 +++++++++--- > 1 file changed, 9 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c > index cbbda94c3dab..0b92b494117f 100644 > --- a/drivers/gpu/drm/i915/display/intel_bios.c > +++ b/drivers/gpu/drm/i915/display/intel_bios.c > @@ -2964,6 +2964,8 @@ static const struct bdb_header *get_bdb_header(const struct vbt_header *vbt) > return _vbt + vbt->bdb_offset; > } > > +static const char vbt_signature[4] = "$VBT"; Always a bit scary to add strings without termination, but I guess it's justified here. Reviewed-by: Jani Nikula <jani.nikula@intel.com> > + > /** > * 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 *)"$VBT")) > + if (ioread32(oprom + i) != *((const u32 *)vbt_signature)) > continue; > > p = oprom + i;
On Thu, Sep 12, 2024 at 03:15:52PM +0300, Jani Nikula wrote: > On Tue, 10 Sep 2024, Ville Syrjala <ville.syrjala@linux.intel.com> wrote: > > From: Ville Syrjälä <ville.syrjala@linux.intel.com> > > > > Replace the three hand rolled "$VBT"s with a vbt_signature[] > > to avoid accidents. > > > > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > > --- > > 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] = "$VBT"; > > Always a bit scary to add strings without termination, but I guess it's > justified here. I guess we could make it look less like a string with eg. static const u8 vbt_signature[] = { '$', 'V', 'B', 'T' }; ? > Reviewed-by: Jani Nikula <jani.nikula@intel.com> > > > > + > > /** > > * 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 *)"$VBT")) > > + if (ioread32(oprom + i) != *((const u32 *)vbt_signature)) > > continue; > > > > p = oprom + i; > > -- > Jani Nikula, Intel
On Fri, 20 Sep 2024, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote: > On Thu, Sep 12, 2024 at 03:15:52PM +0300, Jani Nikula wrote: >> On Tue, 10 Sep 2024, Ville Syrjala <ville.syrjala@linux.intel.com> wrote: >> > From: Ville Syrjälä <ville.syrjala@linux.intel.com> >> > >> > Replace the three hand rolled "$VBT"s with a vbt_signature[] >> > to avoid accidents. >> > >> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> >> > --- >> > 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] = "$VBT"; >> >> Always a bit scary to add strings without termination, but I guess it's >> justified here. > > I guess we could make it look less like a string with eg. > static const u8 vbt_signature[] = { '$', 'V', 'B', 'T' }; > ? Alternatively, static const char *vbt_signature = "$VBT"; > >> Reviewed-by: Jani Nikula <jani.nikula@intel.com> >> >> >> > + >> > /** >> > * intel_bios_is_valid_vbt - does the given buffer contain a valid VBT >> > * @display: display device >> > @@ -2986,7 +2988,7 @@ bool intel_bios_is_valid_vbt(struct intel_display *display, >> > return false; >> > } >> > >> > - if (memcmp(vbt->signature, "$VBT", 4)) { >> > + if (memcmp(vbt->signature, vbt_signature, sizeof(vbt_signature))) { But then this would need strlen() >> > 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)); And maybe this could be sizeof(vbt_signature) < sizeof(u32) All of the alternatives are a bit disappointing, so maybe let's just roll with the patch you already have here? BR, Jani. >> > + >> > 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
On Mon, Sep 23, 2024 at 12:12:39PM +0300, Jani Nikula wrote: > On Fri, 20 Sep 2024, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote: > > On Thu, Sep 12, 2024 at 03:15:52PM +0300, Jani Nikula wrote: > >> On Tue, 10 Sep 2024, Ville Syrjala <ville.syrjala@linux.intel.com> wrote: > >> > From: Ville Syrjälä <ville.syrjala@linux.intel.com> > >> > > >> > Replace the three hand rolled "$VBT"s with a vbt_signature[] > >> > to avoid accidents. > >> > > >> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > >> > --- > >> > drivers/gpu/drm/i915/display/intel_bios.c | 12 +++++++++--- > >> > 1 file changed, 9 insertions(+), 3 deletions(-) > >> > > >> > diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c > >> > index cbbda94c3dab..0b92b494117f 100644 > >> > --- a/drivers/gpu/drm/i915/display/intel_bios.c > >> > +++ b/drivers/gpu/drm/i915/display/intel_bios.c > >> > @@ -2964,6 +2964,8 @@ static const struct bdb_header *get_bdb_header(const struct vbt_header *vbt) > >> > return _vbt + vbt->bdb_offset; > >> > } > >> > > >> > +static const char vbt_signature[4] = "$VBT"; > >> > >> Always a bit scary to add strings without termination, but I guess it's > >> justified here. > > > > I guess we could make it look less like a string with eg. > > static const u8 vbt_signature[] = { '$', 'V', 'B', 'T' }; > > ? > > Alternatively, > > static const char *vbt_signature = "$VBT"; Or could just be something like: static const char vbt_signature[] = "$VBT"; static const int vbt_signature_len = 4; BUILD_BUG_ON(vbt_signature_len != sizeof(vbt_signature) - 1); BUILD_BUG_ON(vbt_signature_len != sizeof(u32)); and use vbt_signature_len instead sizeof(vbt_signature) everwhere. > > > > >> Reviewed-by: Jani Nikula <jani.nikula@intel.com> > >> > >> > >> > + > >> > /** > >> > * intel_bios_is_valid_vbt - does the given buffer contain a valid VBT > >> > * @display: display device > >> > @@ -2986,7 +2988,7 @@ bool intel_bios_is_valid_vbt(struct intel_display *display, > >> > return false; > >> > } > >> > > >> > - if (memcmp(vbt->signature, "$VBT", 4)) { > >> > + if (memcmp(vbt->signature, vbt_signature, sizeof(vbt_signature))) { > > But then this would need strlen() > > >> > 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)); > > And maybe this could be sizeof(vbt_signature) < sizeof(u32) > > All of the alternatives are a bit disappointing, so maybe let's just > roll with the patch you already have here? > > BR, > Jani. > > >> > + > >> > 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 > > -- > Jani Nikula, Intel
On Mon, 23 Sep 2024, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote: > On Mon, Sep 23, 2024 at 12:12:39PM +0300, Jani Nikula wrote: >> On Fri, 20 Sep 2024, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote: >> > On Thu, Sep 12, 2024 at 03:15:52PM +0300, Jani Nikula wrote: >> >> On Tue, 10 Sep 2024, Ville Syrjala <ville.syrjala@linux.intel.com> wrote: >> >> > From: Ville Syrjälä <ville.syrjala@linux.intel.com> >> >> > >> >> > Replace the three hand rolled "$VBT"s with a vbt_signature[] >> >> > to avoid accidents. >> >> > >> >> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> >> >> > --- >> >> > drivers/gpu/drm/i915/display/intel_bios.c | 12 +++++++++--- >> >> > 1 file changed, 9 insertions(+), 3 deletions(-) >> >> > >> >> > diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c >> >> > index cbbda94c3dab..0b92b494117f 100644 >> >> > --- a/drivers/gpu/drm/i915/display/intel_bios.c >> >> > +++ b/drivers/gpu/drm/i915/display/intel_bios.c >> >> > @@ -2964,6 +2964,8 @@ static const struct bdb_header *get_bdb_header(const struct vbt_header *vbt) >> >> > return _vbt + vbt->bdb_offset; >> >> > } >> >> > >> >> > +static const char vbt_signature[4] = "$VBT"; >> >> >> >> Always a bit scary to add strings without termination, but I guess it's >> >> justified here. >> > >> > I guess we could make it look less like a string with eg. >> > static const u8 vbt_signature[] = { '$', 'V', 'B', 'T' }; >> > ? >> >> Alternatively, >> >> static const char *vbt_signature = "$VBT"; > > Or could just be something like: > > static const char vbt_signature[] = "$VBT"; > static const int vbt_signature_len = 4; > > BUILD_BUG_ON(vbt_signature_len != sizeof(vbt_signature) - 1); > BUILD_BUG_ON(vbt_signature_len != sizeof(u32)); > > and use vbt_signature_len instead sizeof(vbt_signature) everwhere. Works for me, up to you. BR, Jani. > >> >> > >> >> Reviewed-by: Jani Nikula <jani.nikula@intel.com> >> >> >> >> >> >> > + >> >> > /** >> >> > * intel_bios_is_valid_vbt - does the given buffer contain a valid VBT >> >> > * @display: display device >> >> > @@ -2986,7 +2988,7 @@ bool intel_bios_is_valid_vbt(struct intel_display *display, >> >> > return false; >> >> > } >> >> > >> >> > - if (memcmp(vbt->signature, "$VBT", 4)) { >> >> > + if (memcmp(vbt->signature, vbt_signature, sizeof(vbt_signature))) { >> >> But then this would need strlen() >> >> >> > 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)); >> >> And maybe this could be sizeof(vbt_signature) < sizeof(u32) >> >> All of the alternatives are a bit disappointing, so maybe let's just >> roll with the patch you already have here? >> >> BR, >> Jani. >> >> >> > + >> >> > 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 >> >> -- >> Jani Nikula, Intel
On Mon, Sep 23, 2024 at 05:24:46PM +0300, Jani Nikula wrote: > On Mon, 23 Sep 2024, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote: > > On Mon, Sep 23, 2024 at 12:12:39PM +0300, Jani Nikula wrote: > >> On Fri, 20 Sep 2024, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote: > >> > On Thu, Sep 12, 2024 at 03:15:52PM +0300, Jani Nikula wrote: > >> >> On Tue, 10 Sep 2024, Ville Syrjala <ville.syrjala@linux.intel.com> wrote: > >> >> > From: Ville Syrjälä <ville.syrjala@linux.intel.com> > >> >> > > >> >> > Replace the three hand rolled "$VBT"s with a vbt_signature[] > >> >> > to avoid accidents. > >> >> > > >> >> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > >> >> > --- > >> >> > drivers/gpu/drm/i915/display/intel_bios.c | 12 +++++++++--- > >> >> > 1 file changed, 9 insertions(+), 3 deletions(-) > >> >> > > >> >> > diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c > >> >> > index cbbda94c3dab..0b92b494117f 100644 > >> >> > --- a/drivers/gpu/drm/i915/display/intel_bios.c > >> >> > +++ b/drivers/gpu/drm/i915/display/intel_bios.c > >> >> > @@ -2964,6 +2964,8 @@ static const struct bdb_header *get_bdb_header(const struct vbt_header *vbt) > >> >> > return _vbt + vbt->bdb_offset; > >> >> > } > >> >> > > >> >> > +static const char vbt_signature[4] = "$VBT"; > >> >> > >> >> Always a bit scary to add strings without termination, but I guess it's > >> >> justified here. > >> > > >> > I guess we could make it look less like a string with eg. > >> > static const u8 vbt_signature[] = { '$', 'V', 'B', 'T' }; > >> > ? > >> > >> Alternatively, > >> > >> static const char *vbt_signature = "$VBT"; > > > > Or could just be something like: > > > > static const char vbt_signature[] = "$VBT"; > > static const int vbt_signature_len = 4; > > > > BUILD_BUG_ON(vbt_signature_len != sizeof(vbt_signature) - 1); > > BUILD_BUG_ON(vbt_signature_len != sizeof(u32)); > > > > and use vbt_signature_len instead sizeof(vbt_signature) everwhere. > > Works for me, up to you. I'll roll with that. I guess it's safer to have the '\0' in case someone gets the urge to do something like printk("Unable to find %s ...\n", vbt_signature) etc.
diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c index cbbda94c3dab..0b92b494117f 100644 --- a/drivers/gpu/drm/i915/display/intel_bios.c +++ b/drivers/gpu/drm/i915/display/intel_bios.c @@ -2964,6 +2964,8 @@ static const struct bdb_header *get_bdb_header(const struct vbt_header *vbt) return _vbt + vbt->bdb_offset; } +static const char vbt_signature[4] = "$VBT"; + /** * 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;