linux-kernel - [PATCH AUTOSEL 5.15 22/46] drm/rockchip: Use drm_mode

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Date:   Sun, 18 Dec 2022 11:12:20 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Ville Syrjälä 
        <ville.syrjala@...ux.intel.com>, Sandy Huang <hjc@...k-chips.com>,
        Heiko Stübner <heiko@...ech.de>,
        linux-arm-kernel@...ts.infradead.org,
        linux-rockchip@...ts.infradead.org,
        Daniel Vetter <daniel.vetter@...ll.ch>,
        Sasha Levin <sashal@...nel.org>, airlied@...il.com,
        daniel@...ll.ch, dri-devel@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 5.15 22/46] drm/rockchip: Use drm_mode_copy()

From: Ville Syrjälä <ville.syrjala@...ux.intel.com>

[ Upstream commit 2bfaa28000d2830d3209161a4541cce0660e1b84 ]

struct drm_display_mode embeds a list head, so overwriting
the full struct with another one will corrupt the list
(if the destination mode is on a list). Use drm_mode_copy()
instead which explicitly preserves the list head of
the destination mode.

Even if we know the destination mode is not on any list
using drm_mode_copy() seems decent as it sets a good
example. Bad examples of not using it might eventually
get copied into code where preserving the list head
actually matters.

Obviously one case not covered here is when the mode
itself is embedded in a larger structure and the whole
structure is copied. But if we are careful when copying
into modes embedded in structures I think we can be a
little more reassured that bogus list heads haven't been
propagated in.

@is_mode_copy@
@@
drm_mode_copy(...)
{
...
}

@depends on !is_mode_copy@
struct drm_display_mode *mode;
expression E, S;
@@
(
- *mode = E
+ drm_mode_copy(mode, &E)
|
- memcpy(mode, E, S)
+ drm_mode_copy(mode, E)
)

@depends on !is_mode_copy@
struct drm_display_mode mode;
expression E;
@@
(
- mode = E
+ drm_mode_copy(&mode, &E)
|
- memcpy(&mode, E, S)
+ drm_mode_copy(&mode, E)
)

@@
struct drm_display_mode *mode;
@@
- &*mode
+ mode

Signed-off-by: Ville Syrjälä <ville.syrjala@...ux.intel.com>
Cc: Sandy Huang <hjc@...k-chips.com>
Cc: "Heiko Stübner" <heiko@...ech.de>
Cc: linux-arm-kernel@...ts.infradead.org
Cc: linux-rockchip@...ts.infradead.org
Link: https://patchwork.freedesktop.org/patch/msgid/20221107192545.9896-7-ville.syrjala@linux.intel.com
Reviewed-by: Daniel Vetter <daniel.vetter@...ll.ch>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/rockchip/cdn-dp-core.c | 2 +-
 drivers/gpu/drm/rockchip/inno_hdmi.c   | 2 +-
 drivers/gpu/drm/rockchip/rk3066_hdmi.c | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/rockchip/cdn-dp-core.c b/drivers/gpu/drm/rockchip/cdn-dp-core.c
index 6b5d0722afa6..20e63cadec8c 100644
--- a/drivers/gpu/drm/rockchip/cdn-dp-core.c
+++ b/drivers/gpu/drm/rockchip/cdn-dp-core.c
@@ -565,7 +565,7 @@ static void cdn_dp_encoder_mode_set(struct drm_encoder *encoder,
 	video->v_sync_polarity = !!(mode->flags & DRM_MODE_FLAG_NVSYNC);
 	video->h_sync_polarity = !!(mode->flags & DRM_MODE_FLAG_NHSYNC);
 
-	memcpy(&dp->mode, adjusted, sizeof(*mode));
+	drm_mode_copy(&dp->mode, adjusted);
 }
 
 static bool cdn_dp_check_link_status(struct cdn_dp_device *dp)
diff --git a/drivers/gpu/drm/rockchip/inno_hdmi.c b/drivers/gpu/drm/rockchip/inno_hdmi.c
index 7afdc54eb3ec..78120da5e63a 100644
--- a/drivers/gpu/drm/rockchip/inno_hdmi.c
+++ b/drivers/gpu/drm/rockchip/inno_hdmi.c
@@ -488,7 +488,7 @@ static void inno_hdmi_encoder_mode_set(struct drm_encoder *encoder,
 	inno_hdmi_setup(hdmi, adj_mode);
 
 	/* Store the display mode for plugin/DPMS poweron events */
-	memcpy(&hdmi->previous_mode, adj_mode, sizeof(hdmi->previous_mode));
+	drm_mode_copy(&hdmi->previous_mode, adj_mode);
 }
 
 static void inno_hdmi_encoder_enable(struct drm_encoder *encoder)
diff --git a/drivers/gpu/drm/rockchip/rk3066_hdmi.c b/drivers/gpu/drm/rockchip/rk3066_hdmi.c
index 1c546c3a8998..17e7c40a9e7b 100644
--- a/drivers/gpu/drm/rockchip/rk3066_hdmi.c
+++ b/drivers/gpu/drm/rockchip/rk3066_hdmi.c
@@ -383,7 +383,7 @@ rk3066_hdmi_encoder_mode_set(struct drm_encoder *encoder,
 	struct rk3066_hdmi *hdmi = to_rk3066_hdmi(encoder);
 
 	/* Store the display mode for plugin/DPMS poweron events. */
-	memcpy(&hdmi->previous_mode, adj_mode, sizeof(hdmi->previous_mode));
+	drm_mode_copy(&hdmi->previous_mode, adj_mode);
 }
 
 static void rk3066_hdmi_encoder_enable(struct drm_encoder *encoder)
-- 
2.35.1