From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CD2E610E6 for ; Tue, 20 Dec 2022 01:22:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8E1CDC43398; Tue, 20 Dec 2022 01:22:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1671499361; bh=EMhuF+Ds/wbIUUyllvsN2+ovUgWEdqObC3iziQCOfOM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gAKZaiPHMQsR2fGW60yd51+l+b281ZLnt7FwS3B0eNaABv847afXMxLE8GS60W5AH t0b2E0nRcuHVLnCHtbz3+SCK4isuuj2OK241vm6/aZBJ7bQSMw3zWxxQ9mtwp3RCu8 8tu7GiyitMyf1LX7vuIQ/8hfwBKU1po8byP9BrN3WuLvmbiTMmOvWCvpKjQiVhbHVF w9FB28kvcM4FN8fx1eyimJyAZnph3wuToczniAWv7ajfHDZKV/3LlUcjA6XszeytpZ UTxYAFFdgcMeI2IY+Nt//FCClxJivTuwPiPX30XV6qg7sdNoUaN42oxjfL0saZ0Zvf EDJszSVo7FdEg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Nathan Chancellor , Kees Cook , Sasha Levin , alain.volmat@foss.st.com, airlied@gmail.com, daniel@ffwll.ch, ndesaulniers@google.com, dri-devel@lists.freedesktop.org, llvm@lists.linux.dev Subject: [PATCH AUTOSEL 4.19 2/3] drm/sti: Fix return type of sti_{dvo,hda,hdmi}_connector_mode_valid() Date: Mon, 19 Dec 2022 20:22:35 -0500 Message-Id: <20221220012237.1222810-2-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221220012237.1222810-1-sashal@kernel.org> References: <20221220012237.1222810-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: Nathan Chancellor [ Upstream commit 0ad811cc08a937d875cbad0149c1bab17f84ba05 ] With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG), indirect call targets are validated against the expected function pointer prototype to make sure the call target is valid to help mitigate ROP attacks. If they are not identical, there is a failure at run time, which manifests as either a kernel panic or thread getting killed. A proposed warning in clang aims to catch these at compile time, which reveals: drivers/gpu/drm/sti/sti_hda.c:637:16: error: incompatible function pointer types initializing 'enum drm_mode_status (*)(struct drm_connector *, struct drm_display_mode *)' with an expression of type 'int (struct drm_connector *, struct drm_display_mode *)' [-Werror,-Wincompatible-function-pointer-types-strict] .mode_valid = sti_hda_connector_mode_valid, ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/sti/sti_dvo.c:376:16: error: incompatible function pointer types initializing 'enum drm_mode_status (*)(struct drm_connector *, struct drm_display_mode *)' with an expression of type 'int (struct drm_connector *, struct drm_display_mode *)' [-Werror,-Wincompatible-function-pointer-types-strict] .mode_valid = sti_dvo_connector_mode_valid, ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/sti/sti_hdmi.c:1035:16: error: incompatible function pointer types initializing 'enum drm_mode_status (*)(struct drm_connector *, struct drm_display_mode *)' with an expression of type 'int (struct drm_connector *, struct drm_display_mode *)' [-Werror,-Wincompatible-function-pointer-types-strict] .mode_valid = sti_hdmi_connector_mode_valid, ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ->mode_valid() in 'struct drm_connector_helper_funcs' expects a return type of 'enum drm_mode_status', not 'int'. Adjust the return type of sti_{dvo,hda,hdmi}_connector_mode_valid() to match the prototype's to resolve the warning and CFI failure. Link: https://github.com/ClangBuiltLinux/linux/issues/1750 Signed-off-by: Nathan Chancellor Reviewed-by: Kees Cook Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20221102155623.3042869-1-nathan@kernel.org Signed-off-by: Sasha Levin --- drivers/gpu/drm/sti/sti_dvo.c | 5 +++-- drivers/gpu/drm/sti/sti_hda.c | 5 +++-- drivers/gpu/drm/sti/sti_hdmi.c | 5 +++-- 3 files changed, 9 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/sti/sti_dvo.c b/drivers/gpu/drm/sti/sti_dvo.c index b08376b7611b..08d096822f24 100644 --- a/drivers/gpu/drm/sti/sti_dvo.c +++ b/drivers/gpu/drm/sti/sti_dvo.c @@ -346,8 +346,9 @@ static int sti_dvo_connector_get_modes(struct drm_connector *connector) #define CLK_TOLERANCE_HZ 50 -static int sti_dvo_connector_mode_valid(struct drm_connector *connector, - struct drm_display_mode *mode) +static enum drm_mode_status +sti_dvo_connector_mode_valid(struct drm_connector *connector, + struct drm_display_mode *mode) { int target = mode->clock * 1000; int target_min = target - CLK_TOLERANCE_HZ; diff --git a/drivers/gpu/drm/sti/sti_hda.c b/drivers/gpu/drm/sti/sti_hda.c index 19b9b5ed1297..9974c19c04c4 100644 --- a/drivers/gpu/drm/sti/sti_hda.c +++ b/drivers/gpu/drm/sti/sti_hda.c @@ -596,8 +596,9 @@ static int sti_hda_connector_get_modes(struct drm_connector *connector) #define CLK_TOLERANCE_HZ 50 -static int sti_hda_connector_mode_valid(struct drm_connector *connector, - struct drm_display_mode *mode) +static enum drm_mode_status +sti_hda_connector_mode_valid(struct drm_connector *connector, + struct drm_display_mode *mode) { int target = mode->clock * 1000; int target_min = target - CLK_TOLERANCE_HZ; diff --git a/drivers/gpu/drm/sti/sti_hdmi.c b/drivers/gpu/drm/sti/sti_hdmi.c index ccf718404a1c..b5199dd4b817 100644 --- a/drivers/gpu/drm/sti/sti_hdmi.c +++ b/drivers/gpu/drm/sti/sti_hdmi.c @@ -989,8 +989,9 @@ static int sti_hdmi_connector_get_modes(struct drm_connector *connector) #define CLK_TOLERANCE_HZ 50 -static int sti_hdmi_connector_mode_valid(struct drm_connector *connector, - struct drm_display_mode *mode) +static enum drm_mode_status +sti_hdmi_connector_mode_valid(struct drm_connector *connector, + struct drm_display_mode *mode) { int target = mode->clock * 1000; int target_min = target - CLK_TOLERANCE_HZ; -- 2.35.1