From: Nathan Huckleberry <[email protected]>
The mode_valid field in drm_bridge_helper_funcs is expected to be of
type
enum drm_mode_status (* mode_valid) (struct drm_bridge *bridge,
struct drm_display_mode *mode);
The mismatched return type breaks forward edge kCFI since the underlying
function definition does not match the function hook definition. A new
warning in clang will catch this at compile time:
drivers/gpu/drm/xlnx/zynqmp_dp.c:1573:16: error: incompatible function pointer types initializing 'enum drm_mode_status (*)(struct drm_bridge *, const struct drm_display_info *, const struct drm_display_mode *)' with an expression of type 'int (struct drm_bridge *, const struct drm_display_info *, const struct drm_display_mode *)' [-Werror,-Wincompatible-function-pointer-types-strict]
.mode_valid = zynqmp_dp_bridge_mode_valid,
^~~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
The return type of zynqmp_dp_bridge_mode_valid should be changed from
int to enum drm_mode_status.
Reported-by: Dan Carpenter <[email protected]>
Link: https://github.com/ClangBuiltLinux/linux/issues/1703
Link: https://github.com/ClangBuiltLinux/linux/issues/1750
Signed-off-by: Nathan Huckleberry <[email protected]>
Reviewed-by: Laurent Pinchart <[email protected]>
[nathan: Rebase on drm-misc-next and fix conflicts
Add note about new clang warning]
Signed-off-by: Nathan Chancellor <[email protected]>
---
Please consider picking this up so that it makes 6.2.
v2:
- Take over for Nathan, as he is busy with other matters.
- Rebase on drm-misc-next and resolve conflicts.
- Add a note about new clang warning that will catch this issue at
compile time.
v1: https://lore.kernel.org/[email protected]/
drivers/gpu/drm/xlnx/zynqmp_dp.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c
index 7c9ae167eac7..0a7b466446fb 100644
--- a/drivers/gpu/drm/xlnx/zynqmp_dp.c
+++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c
@@ -1362,9 +1362,10 @@ static void zynqmp_dp_bridge_detach(struct drm_bridge *bridge)
zynqmp_dp_aux_cleanup(dp);
}
-static int zynqmp_dp_bridge_mode_valid(struct drm_bridge *bridge,
- const struct drm_display_info *info,
- const struct drm_display_mode *mode)
+static enum drm_mode_status
+zynqmp_dp_bridge_mode_valid(struct drm_bridge *bridge,
+ const struct drm_display_info *info,
+ const struct drm_display_mode *mode)
{
struct zynqmp_dp *dp = bridge_to_dp(bridge);
int rate;
base-commit: 1a0257c352638916fdaffaac2ddedb8e049312f3
--
2.38.1
Hi Nathan,
Thank you for the patch.
On Tue, Nov 08, 2022 at 05:14:25PM -0700, Nathan Chancellor wrote:
> From: Nathan Huckleberry <[email protected]>
>
> The mode_valid field in drm_bridge_helper_funcs is expected to be of
> type
> enum drm_mode_status (* mode_valid) (struct drm_bridge *bridge,
> struct drm_display_mode *mode);
>
> The mismatched return type breaks forward edge kCFI since the underlying
> function definition does not match the function hook definition. A new
> warning in clang will catch this at compile time:
>
> drivers/gpu/drm/xlnx/zynqmp_dp.c:1573:16: error: incompatible function pointer types initializing 'enum drm_mode_status (*)(struct drm_bridge *, const struct drm_display_info *, const struct drm_display_mode *)' with an expression of type 'int (struct drm_bridge *, const struct drm_display_info *, const struct drm_display_mode *)' [-Werror,-Wincompatible-function-pointer-types-strict]
> .mode_valid = zynqmp_dp_bridge_mode_valid,
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~
> 1 error generated.
>
> The return type of zynqmp_dp_bridge_mode_valid should be changed from
> int to enum drm_mode_status.
>
> Reported-by: Dan Carpenter <[email protected]>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1703
> Link: https://github.com/ClangBuiltLinux/linux/issues/1750
> Signed-off-by: Nathan Huckleberry <[email protected]>
> Reviewed-by: Laurent Pinchart <[email protected]>
> [nathan: Rebase on drm-misc-next and fix conflicts
> Add note about new clang warning]
> Signed-off-by: Nathan Chancellor <[email protected]>
> ---
>
> Please consider picking this up so that it makes 6.2.
I'll send a pull request shortly.
> v2:
> - Take over for Nathan, as he is busy with other matters.
> - Rebase on drm-misc-next and resolve conflicts.
> - Add a note about new clang warning that will catch this issue at
> compile time.
>
> v1: https://lore.kernel.org/[email protected]/
>
> drivers/gpu/drm/xlnx/zynqmp_dp.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c
> index 7c9ae167eac7..0a7b466446fb 100644
> --- a/drivers/gpu/drm/xlnx/zynqmp_dp.c
> +++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c
> @@ -1362,9 +1362,10 @@ static void zynqmp_dp_bridge_detach(struct drm_bridge *bridge)
> zynqmp_dp_aux_cleanup(dp);
> }
>
> -static int zynqmp_dp_bridge_mode_valid(struct drm_bridge *bridge,
> - const struct drm_display_info *info,
> - const struct drm_display_mode *mode)
> +static enum drm_mode_status
> +zynqmp_dp_bridge_mode_valid(struct drm_bridge *bridge,
> + const struct drm_display_info *info,
> + const struct drm_display_mode *mode)
> {
> struct zynqmp_dp *dp = bridge_to_dp(bridge);
> int rate;
>
> base-commit: 1a0257c352638916fdaffaac2ddedb8e049312f3
--
Regards,
Laurent Pinchart
On Tue, Nov 08, 2022 at 05:14:25PM -0700, Nathan Chancellor wrote:
> From: Nathan Huckleberry <[email protected]>
>
> The mode_valid field in drm_bridge_helper_funcs is expected to be of
> type
> enum drm_mode_status (* mode_valid) (struct drm_bridge *bridge,
> struct drm_display_mode *mode);
>
> The mismatched return type breaks forward edge kCFI since the underlying
> function definition does not match the function hook definition. A new
> warning in clang will catch this at compile time:
>
> drivers/gpu/drm/xlnx/zynqmp_dp.c:1573:16: error: incompatible function pointer types initializing 'enum drm_mode_status (*)(struct drm_bridge *, const struct drm_display_info *, const struct drm_display_mode *)' with an expression of type 'int (struct drm_bridge *, const struct drm_display_info *, const struct drm_display_mode *)' [-Werror,-Wincompatible-function-pointer-types-strict]
> .mode_valid = zynqmp_dp_bridge_mode_valid,
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~
> 1 error generated.
>
> The return type of zynqmp_dp_bridge_mode_valid should be changed from
> int to enum drm_mode_status.
>
> Reported-by: Dan Carpenter <[email protected]>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1703
> Link: https://github.com/ClangBuiltLinux/linux/issues/1750
> Signed-off-by: Nathan Huckleberry <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
--
Kees Cook