summary refs log tree commit diff
path: root/drivers/gpu/drm/stm
diff options
context:
space:
mode:
authorYannick Fertré <yannick.fertre@st.com>2019-04-03 11:20:16 +0200
committerBenjamin Gaignard <benjamin.gaignard@linaro.org>2019-04-24 13:52:06 +0200
commit77756ad6d08fb3f276d357be4c318f871dab8734 (patch)
treede84d976d1f6d8b398d73bc486ba1deb4da317ef /drivers/gpu/drm/stm
parent8ceb8568d6e8d53dc000a9eeacd47c8f298c38f0 (diff)
downloadlinux-77756ad6d08fb3f276d357be4c318f871dab8734.tar.gz
drm/stm: ltdc: limit number of layer to avoid memory overflow
If the number of layer is greater than LTDC_MAX_LAYER, we can have
memory overflow when reading plane_fpsi[].

Signed-off-by: Yannick Fertré <yannick.fertre@st.com>
Acked-by: Philippe Cornu <philippe.cornu@st.com>
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1554283216-2700-1-git-send-email-yannick.fertre@st.com
Diffstat (limited to 'drivers/gpu/drm/stm')
-rw-r--r--drivers/gpu/drm/stm/ltdc.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
index cde2f18ce1c1..17438c28d9fc 100644
--- a/drivers/gpu/drm/stm/ltdc.c
+++ b/drivers/gpu/drm/stm/ltdc.c
@@ -1021,10 +1021,13 @@ static int ltdc_get_caps(struct drm_device *ddev)
 	struct ltdc_device *ldev = ddev->dev_private;
 	u32 bus_width_log2, lcr, gc2r;
 
-	/* at least 1 layer must be managed */
+	/*
+	 * at least 1 layer must be managed & the number of layers
+	 * must not exceed LTDC_MAX_LAYER
+	 */
 	lcr = reg_read(ldev->regs, LTDC_LCR);
 
-	ldev->caps.nb_layers = max_t(int, lcr, 1);
+	ldev->caps.nb_layers = clamp((int)lcr, 1, LTDC_MAX_LAYER);
 
 	/* set data bus width */
 	gc2r = reg_read(ldev->regs, LTDC_GC2R);