From: Ville Syrjälä ville.syrjala@linux.intel.com
[ Upstream commit 442cf8e22ba25a77cb9092d78733fdbac9844e50 ]
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
Cc: Alain Volmat alain.volmat@foss.st.com Signed-off-by: Ville Syrjälä ville.syrjala@linux.intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20221107192545.9896-8-ville.sy... Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/sti/sti_dvo.c | 2 +- drivers/gpu/drm/sti/sti_hda.c | 2 +- drivers/gpu/drm/sti/sti_hdmi.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/sti/sti_dvo.c b/drivers/gpu/drm/sti/sti_dvo.c index 852bf2293b05..872a06670b34 100644 --- a/drivers/gpu/drm/sti/sti_dvo.c +++ b/drivers/gpu/drm/sti/sti_dvo.c @@ -288,7 +288,7 @@ static void sti_dvo_set_mode(struct drm_bridge *bridge,
DRM_DEBUG_DRIVER("\n");
- memcpy(&dvo->mode, mode, sizeof(struct drm_display_mode)); + drm_mode_copy(&dvo->mode, mode);
/* According to the path used (main or aux), the dvo clocks should * have a different parent clock. */ diff --git a/drivers/gpu/drm/sti/sti_hda.c b/drivers/gpu/drm/sti/sti_hda.c index 0399bb18d387..9a7a9aa5445e 100644 --- a/drivers/gpu/drm/sti/sti_hda.c +++ b/drivers/gpu/drm/sti/sti_hda.c @@ -518,7 +518,7 @@ static void sti_hda_set_mode(struct drm_bridge *bridge,
DRM_DEBUG_DRIVER("\n");
- memcpy(&hda->mode, mode, sizeof(struct drm_display_mode)); + drm_mode_copy(&hda->mode, mode);
if (!hda_get_mode_idx(hda->mode, &mode_idx)) { DRM_ERROR("Undefined mode\n"); diff --git a/drivers/gpu/drm/sti/sti_hdmi.c b/drivers/gpu/drm/sti/sti_hdmi.c index bbb195a92e93..c5b2f36c5feb 100644 --- a/drivers/gpu/drm/sti/sti_hdmi.c +++ b/drivers/gpu/drm/sti/sti_hdmi.c @@ -924,7 +924,7 @@ static void sti_hdmi_set_mode(struct drm_bridge *bridge, DRM_DEBUG_DRIVER("\n");
/* Copy the drm display mode in the connector local structure */ - memcpy(&hdmi->mode, mode, sizeof(struct drm_display_mode)); + drm_mode_copy(&hdmi->mode, mode);
/* Update clock framerate according to the selected mode */ ret = clk_set_rate(hdmi->clk_pix, mode->clock * 1000);