On 2/18/2022 2:03 AM, Ville Syrjala wrote:
From: Ville Syrjälä ville.syrjala@linux.intel.com
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: Rob Clark robdclark@gmail.com Cc: Sean Paul sean@poorly.run Cc: Abhinav Kumar quic_abhinavk@quicinc.com Cc: linux-arm-msm@vger.kernel.org Cc: freedreno@lists.freedesktop.org Signed-off-by: Ville Syrjälä ville.syrjala@linux.intel.com
Reviewed-by: Abhinav Kumar quic_abhinavk@quicinc.com
drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c | 2 +- drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c | 2 +- drivers/gpu/drm/msm/dp/dp_display.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c index 34a6940d12c5..57592052af23 100644 --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c @@ -157,7 +157,7 @@ static void dpu_encoder_phys_cmd_mode_set( DPU_ERROR("invalid args\n"); return; }
- phys_enc->cached_mode = *adj_mode;
- drm_mode_copy(&phys_enc->cached_mode, adj_mode); DPU_DEBUG_CMDENC(cmd_enc, "caching mode:\n"); drm_mode_debug_printmodeline(adj_mode);
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c index e7813c6f7bd9..d5deca07b65a 100644 --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c @@ -370,7 +370,7 @@ static void dpu_encoder_phys_vid_mode_set( struct dpu_encoder_irq *irq;
if (adj_mode) {
phys_enc->cached_mode = *adj_mode;
drm_mode_copy(&phys_enc->cached_mode, adj_mode);diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c index 7cc4d21f2091..2ed6028ca8d6 100644 --- a/drivers/gpu/drm/msm/dp/dp_display.c +++ b/drivers/gpu/drm/msm/dp/dp_display.c @@ -825,7 +825,7 @@ static int dp_display_set_mode(struct msm_dp *dp_display,
dp = container_of(dp_display, struct dp_display_private, dp_display);
- dp->panel->dp_mode.drm_mode = mode->drm_mode;
- drm_mode_copy(&dp->panel->dp_mode.drm_mode, &mode->drm_mode); dp->panel->dp_mode.bpp = mode->bpp; dp->panel->dp_mode.capabilities = mode->capabilities; dp_panel_init_panel_info(dp->panel);