lkml.org 
[lkml]   [2022]   [Dec]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH AUTOSEL 5.4 16/30] drm/sti: Use drm_mode_copy()
    Date
    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.syrjala@linux.intel.com
    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 e55870190bf5..3c65c73aa854 100644
    --- a/drivers/gpu/drm/sti/sti_dvo.c
    +++ b/drivers/gpu/drm/sti/sti_dvo.c
    @@ -287,7 +287,7 @@ 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 94e404f13234..158192680bea 100644
    --- a/drivers/gpu/drm/sti/sti_hda.c
    +++ b/drivers/gpu/drm/sti/sti_hda.c
    @@ -522,7 +522,7 @@ 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 9862c322f0c4..c91ce51836ca 100644
    --- a/drivers/gpu/drm/sti/sti_hdmi.c
    +++ b/drivers/gpu/drm/sti/sti_hdmi.c
    @@ -933,7 +933,7 @@ 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);
    --
    2.35.1
    \
     
     \ /
      Last update: 2022-12-18 17:59    [W:5.806 / U:0.000 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site