From: Harry Wentland harry.wentland@amd.com
[ Upstream commit 2fee84030d12d9fddfa874e4562d71761a129277 ]
When the floor LUT index (drm_fixp2int(lut_index) is the last index of the array the ceil LUT index will point to an entry beyond the array. Make sure we guard against it and use the value of the floor LUT index.
v3: - Drop bits from commit description that didn't contribute anything of value
Fixes: db1f254f2cfa ("drm/vkms: Add support to 1D gamma LUT") Signed-off-by: Harry Wentland harry.wentland@amd.com Cc: Arthur Grillo arthurgrillo@riseup.net Reviewed-by: Arthur Grillo arthurgrillo@riseup.net Reviewed-by: Melissa Wen mwen@igalia.com Signed-off-by: Melissa Wen melissa.srw@gmail.com Link: https://patchwork.freedesktop.org/patch/msgid/20231108163647.106853-6-harry.... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/vkms/vkms_composer.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c index 3c99fb8b54e2d..e7441b227b3ce 100644 --- a/drivers/gpu/drm/vkms/vkms_composer.c +++ b/drivers/gpu/drm/vkms/vkms_composer.c @@ -123,6 +123,8 @@ static u16 apply_lut_to_channel_value(const struct vkms_color_lut *lut, u16 chan enum lut_channel channel) { s64 lut_index = get_lut_index(lut, channel_value); + u16 *floor_lut_value, *ceil_lut_value; + u16 floor_channel_value, ceil_channel_value;
/* * This checks if `struct drm_color_lut` has any gap added by the compiler @@ -130,11 +132,15 @@ static u16 apply_lut_to_channel_value(const struct vkms_color_lut *lut, u16 chan */ static_assert(sizeof(struct drm_color_lut) == sizeof(__u16) * 4);
- u16 *floor_lut_value = (__u16 *)&lut->base[drm_fixp2int(lut_index)]; - u16 *ceil_lut_value = (__u16 *)&lut->base[drm_fixp2int_ceil(lut_index)]; + floor_lut_value = (__u16 *)&lut->base[drm_fixp2int(lut_index)]; + if (drm_fixp2int(lut_index) == (lut->lut_length - 1)) + /* We're at the end of the LUT array, use same value for ceil and floor */ + ceil_lut_value = floor_lut_value; + else + ceil_lut_value = (__u16 *)&lut->base[drm_fixp2int_ceil(lut_index)];
- u16 floor_channel_value = floor_lut_value[channel]; - u16 ceil_channel_value = ceil_lut_value[channel]; + floor_channel_value = floor_lut_value[channel]; + ceil_channel_value = ceil_lut_value[channel];
return lerp_u16(floor_channel_value, ceil_channel_value, lut_index & DRM_FIXED_DECIMAL_MASK);