[PATCH v2] drm/meson: Use 1000ULL when operating with mode->clock

From: I Hsin Cheng <richard120310@gmail.com>
To: neil.armstrong@linaro.org
Cc: maarten.lankhorst@linux.intel.com, mripard@kernel.org,
	tzimmermann@suse.de, airlied@gmail.com, simona@ffwll.ch,
	khilman@baylibre.com, jbrunet@baylibre.com,
	martin.blumenstingl@googlemail.com,
	christophe.jaillet@wanadoo.fr, skhan@linuxfoundation.org,
	dri-devel@lists.freedesktop.org,
	linux-amlogic@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	I Hsin Cheng <richard120310@gmail.com>
Subject: [PATCH v2] drm/meson: Use 1000ULL when operating with mode->clock
Date: Tue,  6 May 2025 02:43:38 +0800	[thread overview]
Message-ID: <20250505184338.678540-1-richard120310@gmail.com> (raw)

Coverity scan reported the usage of "mode->clock * 1000" may lead to
integer overflow. Use "1000ULL" instead of "1000"
when utilizing it to avoid potential integer overflow issue.

Link: https://scan5.scan.coverity.com/#/project-view/10074/10063?selectedIssue=1646759
Signed-off-by: I Hsin Cheng <richard120310@gmail.com>
---
Changelog:

v1 -> v2:
	- Use 1000ULL instead of casting the type of "mode->clock"
	- Refine commit title and message
	- Fix the issue for the evaluation inside drm_mode_status
	  meson_encoder_hdmi_mode_valid() as well

Christophe,
Thanks for your review and your suggestion, I think I should add a tag
for you,too, but I'm not sure what should I add, if you would be so kind
please let me know how should I tag you in the patch.

Best regards,
I Hsin Cheng
---
 drivers/gpu/drm/meson/meson_encoder_hdmi.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/meson/meson_encoder_hdmi.c b/drivers/gpu/drm/meson/meson_encoder_hdmi.c
index 7752d8ac85f0..c08fa93e50a3 100644
--- a/drivers/gpu/drm/meson/meson_encoder_hdmi.c
+++ b/drivers/gpu/drm/meson/meson_encoder_hdmi.c
@@ -75,7 +75,7 @@ static void meson_encoder_hdmi_set_vclk(struct meson_encoder_hdmi *encoder_hdmi,
 	unsigned long long venc_freq;
 	unsigned long long hdmi_freq;
 
-	vclk_freq = mode->clock * 1000;
+	vclk_freq = mode->clock * 1000ULL;
 
 	/* For 420, pixel clock is half unlike venc clock */
 	if (encoder_hdmi->output_bus_fmt == MEDIA_BUS_FMT_UYYVYY8_0_5X24)
@@ -123,7 +123,7 @@ static enum drm_mode_status meson_encoder_hdmi_mode_valid(struct drm_bridge *bri
 	struct meson_encoder_hdmi *encoder_hdmi = bridge_to_meson_encoder_hdmi(bridge);
 	struct meson_drm *priv = encoder_hdmi->priv;
 	bool is_hdmi2_sink = display_info->hdmi.scdc.supported;
-	unsigned long long clock = mode->clock * 1000;
+	unsigned long long clock = mode->clock * 1000ULL;
 	unsigned long long phy_freq;
 	unsigned long long vclk_freq;
 	unsigned long long venc_freq;
-- 
2.43.0


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