From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C1845EED600 for ; Thu, 12 Sep 2024 12:15:57 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8EC7C10EB6A; Thu, 12 Sep 2024 12:15:57 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="b0mWNjrO"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.8]) by gabe.freedesktop.org (Postfix) with ESMTPS id 2B15010EB68; Thu, 12 Sep 2024 12:15:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1726143356; x=1757679356; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version:content-transfer-encoding; bh=dkXbE0V2XUPBdXQ0CPd28jecEyo2WBrv17CENlfSlzo=; b=b0mWNjrOtmznMOc/ZlpPpFKkR12n+4elGRqDFQZZmJZMIJbFfb3vVRwe QFq14CT3hHMYmoAx0oJjyNHZ0gbs9hVx0MJ1EJ4tfZm7E949YeW8Mcsms OdyLgzEKXa/EReH2bg12ms+g1L2liIwba6GaLFUUYNJt2a4/P3Wx41Guu hhJF1VM5yU3NlJqhFe//GKyYG+w3tvSgmqf6IKenGqp9vIjffH424j4yN FJU/HG7D75dtGX6UM2t/CH4Q+IQ1Xzz/XAOkzO+H/JbQR1AzPzG+Rxw8/ aSe3KeKf9AmCyydm72xxzNMtPyVkDRYmpbL8/AcHCY6Ir5ERZLO0NTy74 w==; X-CSE-ConnectionGUID: JWFnb56cTB+vGwraLxcKRA== X-CSE-MsgGUID: GN/Zb0njSnyYAxovHKdmbQ== X-IronPort-AV: E=McAfee;i="6700,10204,11192"; a="42505787" X-IronPort-AV: E=Sophos;i="6.10,223,1719903600"; d="scan'208";a="42505787" Received: from fmviesa006.fm.intel.com ([10.60.135.146]) by fmvoesa102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Sep 2024 05:15:56 -0700 X-CSE-ConnectionGUID: EY8J7mzfQ8CWlTw7TRSm9w== X-CSE-MsgGUID: heJqZZwvRMeLkMFCfEjBWw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,223,1719903600"; d="scan'208";a="67309476" Received: from jnikula-mobl4.fi.intel.com (HELO localhost) ([10.237.66.160]) by fmviesa006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Sep 2024 05:15:54 -0700 From: Jani Nikula To: Ville Syrjala , intel-gfx@lists.freedesktop.org Cc: intel-xe@lists.freedesktop.org Subject: Re: [PATCH 4/5] drm/i915/bios: Extract vbt_signature[] In-Reply-To: <20240910134219.28479-5-ville.syrjala@linux.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20240910134219.28479-1-ville.syrjala@linux.intel.com> <20240910134219.28479-5-ville.syrjala@linux.intel.com> Date: Thu, 12 Sep 2024 15:15:52 +0300 Message-ID: <87y13xf4p3.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" On Tue, 10 Sep 2024, Ville Syrjala wrote: > From: Ville Syrj=C3=A4l=C3=A4 > > Replace the three hand rolled "$VBT"s with a vbt_signature[] > to avoid accidents. > > Signed-off-by: Ville Syrj=C3=A4l=C3=A4 > --- > drivers/gpu/drm/i915/display/intel_bios.c | 12 +++++++++--- > 1 file changed, 9 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/= i915/display/intel_bios.c > index cbbda94c3dab..0b92b494117f 100644 > --- a/drivers/gpu/drm/i915/display/intel_bios.c > +++ b/drivers/gpu/drm/i915/display/intel_bios.c > @@ -2964,6 +2964,8 @@ static const struct bdb_header *get_bdb_header(cons= t struct vbt_header *vbt) > return _vbt + vbt->bdb_offset; > } >=20=20 > +static const char vbt_signature[4] =3D "$VBT"; Always a bit scary to add strings without termination, but I guess it's justified here. Reviewed-by: Jani Nikula > + > /** > * 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; > } >=20=20 > - if (memcmp(vbt->signature, "$VBT", 4)) { > + if (memcmp(vbt->signature, vbt_signature, sizeof(vbt_signature))) { > drm_dbg_kms(display->drm, "VBT invalid signature\n"); > return false; > } > @@ -3082,9 +3084,11 @@ static struct vbt_header *spi_oprom_get_vbt(struct= intel_display *display, > oprom_offset =3D intel_uncore_read(&i915->uncore, OROM_OFFSET); > oprom_offset &=3D OROM_OFFSET_MASK; >=20=20 > + BUILD_BUG_ON(sizeof(vbt_signature) !=3D sizeof(u32)); > + > for (count =3D 0; count < oprom_size; count +=3D 4) { > data =3D intel_spi_read32(&i915->uncore, oprom_offset + count); > - if (data =3D=3D *((const u32 *)"$VBT")) { > + if (data =3D=3D *((const u32 *)vbt_signature)) { > found =3D oprom_offset + count; > break; > } > @@ -3144,9 +3148,11 @@ static struct vbt_header *oprom_get_vbt(struct int= el_display *display, > if (!oprom) > return NULL; >=20=20 > + BUILD_BUG_ON(sizeof(vbt_signature) !=3D sizeof(u32)); > + > /* Scour memory looking for the VBT signature. */ > for (i =3D 0; i + 4 < size; i +=3D 4) { > - if (ioread32(oprom + i) !=3D *((const u32 *)"$VBT")) > + if (ioread32(oprom + i) !=3D *((const u32 *)vbt_signature)) > continue; >=20=20 > p =3D oprom + i; --=20 Jani Nikula, Intel