diff mbox series

[v2] drm/msm/dpu: cast crtc_clk calculation to u64 in _dpu_core_perf_calc_clk()

Message ID 20241029194209.23684-1-zichenxie0106@gmail.com (mailing list archive)
State New, archived
Headers show
Series [v2] drm/msm/dpu: cast crtc_clk calculation to u64 in _dpu_core_perf_calc_clk() | expand

Commit Message

Gax-c Oct. 29, 2024, 7:42 p.m. UTC 
From: Zichen Xie <zichenxie0106@gmail.com>

There may be a potential integer overflow issue in
_dpu_core_perf_calc_clk(). crtc_clk is defined as u64, while
mode->vtotal, mode->hdisplay, and drm_mode_vrefresh(mode) are defined as
a smaller data type. The result of the calculation will be limited to
"int" in this case without correct casting. In screen with high
resolution and high refresh rate, integer overflow may happen.
So, we recommend adding an extra cast to prevent potential
integer overflow.

Fixes: c33b7c0389e1 ("drm/msm/dpu: add support for clk and bw scaling for display")
Signed-off-by: Zichen Xie <zichenxie0106@gmail.com>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
---
v2: Adjust subject.
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Dmitry Baryshkov Oct. 31, 2024, 11:17 p.m. UTC | #1 
On Tue, 29 Oct 2024 14:42:10 -0500, Gax-c wrote:
> There may be a potential integer overflow issue in
> _dpu_core_perf_calc_clk(). crtc_clk is defined as u64, while
> mode->vtotal, mode->hdisplay, and drm_mode_vrefresh(mode) are defined as
> a smaller data type. The result of the calculation will be limited to
> "int" in this case without correct casting. In screen with high
> resolution and high refresh rate, integer overflow may happen.
> So, we recommend adding an extra cast to prevent potential
> integer overflow.
> 
> [...]

Applied, thanks!

[1/1] drm/msm/dpu: cast crtc_clk calculation to u64 in _dpu_core_perf_calc_clk()
      https://gitlab.freedesktop.org/lumag/msm/-/commit/20c7b42d9dbd

Best regards,
diff mbox series

Patch

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.c
index 68fae048a9a8..260accc151d4 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.c
@@ -80,7 +80,7 @@  static u64 _dpu_core_perf_calc_clk(const struct dpu_perf_cfg *perf_cfg,
 
 	mode = &state->adjusted_mode;
 
-	crtc_clk = mode->vtotal * mode->hdisplay * drm_mode_vrefresh(mode);
+	crtc_clk = (u64)mode->vtotal * mode->hdisplay * drm_mode_vrefresh(mode);
 
 	drm_atomic_crtc_for_each_plane(plane, crtc) {
 		pstate = to_dpu_plane_state(plane->state);