From 2d3eec8970335148278a6e350bc4840374f06471 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Fri, 18 Feb 2022 12:03:42 +0200 Subject: [PATCH] drm: Add drm_mode_init() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add a variant of drm_mode_copy() that explicitly clears out the list head of the destination mode. Helpful to guarantee we don't have stack garbage left in there for on-stack modes. Signed-off-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20220218100403.7028-2-ville.syrjala@linux.intel.com Reviewed-by: Andrzej Hajda Reviewed-by: Harry Wentland --- drivers/gpu/drm/drm_modes.c | 17 +++++++++++++++++ include/drm/drm_modes.h | 2 ++ 2 files changed, 19 insertions(+) diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c index 3f819c7a021b..6e7e10f16ec0 100644 --- a/drivers/gpu/drm/drm_modes.c +++ b/drivers/gpu/drm/drm_modes.c @@ -941,6 +941,23 @@ void drm_mode_copy(struct drm_display_mode *dst, const struct drm_display_mode * } EXPORT_SYMBOL(drm_mode_copy); +/** + * drm_mode_init - initialize the mode from another mode + * @dst: mode to overwrite + * @src: mode to copy + * + * Copy an existing mode into another mode, zeroing the + * list head of the destination mode. Typically used + * to guarantee the list head is not left with stack + * garbage in on-stack modes. + */ +void drm_mode_init(struct drm_display_mode *dst, const struct drm_display_mode *src) +{ + memset(dst, 0, sizeof(*dst)); + drm_mode_copy(dst, src); +} +EXPORT_SYMBOL(drm_mode_init); + /** * drm_mode_duplicate - allocate and duplicate an existing mode * @dev: drm_device to allocate the duplicated mode for diff --git a/include/drm/drm_modes.h b/include/drm/drm_modes.h index 2fa6b2c33b3f..a80ae9639e96 100644 --- a/include/drm/drm_modes.h +++ b/include/drm/drm_modes.h @@ -492,6 +492,8 @@ void drm_mode_set_crtcinfo(struct drm_display_mode *p, int adjust_flags); void drm_mode_copy(struct drm_display_mode *dst, const struct drm_display_mode *src); +void drm_mode_init(struct drm_display_mode *dst, + const struct drm_display_mode *src); struct drm_display_mode *drm_mode_duplicate(struct drm_device *dev, const struct drm_display_mode *mode); bool drm_mode_match(const struct drm_display_mode *mode1,