Re: [PATCH v2] drm: xlnx: Fix return type of zynqmp_dp_bridge_mode_valid

2022-11-09 Thread Kees Cook 
On Tue, Nov 08, 2022 at 05:14:25PM -0700, Nathan Chancellor wrote:
> From: Nathan Huckleberry 
> 
> 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 
> Link: https://github.com/ClangBuiltLinux/linux/issues/1703
> Link: https://github.com/ClangBuiltLinux/linux/issues/1750
> Signed-off-by: Nathan Huckleberry 

Reviewed-by: Kees Cook 

-- 
Kees Cook

Re: [PATCH v2] drm: xlnx: Fix return type of zynqmp_dp_bridge_mode_valid

2022-11-09 Thread Laurent Pinchart 
Hi Nathan,

Thank you for the patch.

On Tue, Nov 08, 2022 at 05:14:25PM -0700, Nathan Chancellor wrote:
> From: Nathan Huckleberry 
> 
> 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 
> Link: https://github.com/ClangBuiltLinux/linux/issues/1703
> Link: https://github.com/ClangBuiltLinux/linux/issues/1750
> Signed-off-by: Nathan Huckleberry 
> Reviewed-by: Laurent Pinchart 
> [nathan: Rebase on drm-misc-next and fix conflicts
>  Add note about new clang warning]
> Signed-off-by: Nathan Chancellor 
> ---
> 
> 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/20220913205600.155172-1-nh...@google.com/
> 
>  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

[PATCH v2] drm: xlnx: Fix return type of zynqmp_dp_bridge_mode_valid

2022-11-08 Thread Nathan Chancellor 
From: Nathan Huckleberry 

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 
Link: https://github.com/ClangBuiltLinux/linux/issues/1703
Link: https://github.com/ClangBuiltLinux/linux/issues/1750
Signed-off-by: Nathan Huckleberry 
Reviewed-by: Laurent Pinchart 
[nathan: Rebase on drm-misc-next and fix conflicts
 Add note about new clang warning]
Signed-off-by: Nathan Chancellor 
---

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/20220913205600.155172-1-nh...@google.com/

 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