[PATCH] drm/amdgpu: Fix return types of certain NBIOv7.9 callbacks

From: Nathan Chancellor <nathan@kernel.org>
To: alexander.deucher@amd.com, christian.koenig@amd.com, Xinhui.Pan@amd.com
Cc: ndesaulniers@google.com, trix@redhat.com,
	amd-gfx@lists.freedesktop.org,  dri-devel@lists.freedesktop.org,
	llvm@lists.linux.dev,  patches@lists.linux.dev,
	Nathan Chancellor <nathan@kernel.org>
Subject: [PATCH] drm/amdgpu: Fix return types of certain NBIOv7.9 callbacks
Date: Wed, 24 May 2023 09:44:02 -0700	[thread overview]
Message-ID: <20230524-nbio_v7_9-wincompatible-function-pointer-types-strict-v1-1-da17e01907cf@kernel.org> (raw)

When building with clang's -Wincompatible-function-pointer-types-strict,
which ensures that function pointer signatures match exactly to avoid
tripping clang's Control Flow Integrity (kCFI) checks at run time and
will eventually be turned on for the kernel, the following instances
appear in the NBIOv7.9 code:

  drivers/gpu/drm/amd/amdgpu/nbio_v7_9.c:465:32: error: incompatible function pointer types initializing 'int (*)(struct amdgpu_device *)' with an expression of type 'enum amdgpu_gfx_partition (struct amdgpu_device *)' [-Werror,-Wincompatible-function-pointer-types-strict]
          .get_compute_partition_mode = nbio_v7_9_get_compute_partition_mode,
                                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  drivers/gpu/drm/amd/amdgpu/nbio_v7_9.c:467:31: error: incompatible function pointer types initializing 'u32 (*)(struct amdgpu_device *, u32 *)' (aka 'unsigned int (*)(struct amdgpu_device *, unsigned int *)') with an expression of type 'enum amdgpu_memory_partition (struct amdgpu_device *, u32 *)' (aka 'enum amdgpu_memory_partition (struct amdgpu_device *, unsigned int *)') [-Werror,-Wincompatible-function-pointer-types-strict]
          .get_memory_partition_mode = nbio_v7_9_get_memory_partition_mode,
                                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  2 errors generated.

Change the return types of these callbacks to match the prototypes to
clear up the warning and avoid tripping kCFI at run time. Both functions
return a value from ffs(), which is an integer that can fit into either
int or unsigned int.

Fixes: 11f64eb1472f ("drm/amdgpu: add sysfs node for compute partition mode")
Fixes: 41a717ea8afc ("drm/amdgpu: detect current GPU memory partition mode")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 drivers/gpu/drm/amd/amdgpu/nbio_v7_9.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/nbio_v7_9.c b/drivers/gpu/drm/amd/amdgpu/nbio_v7_9.c
index e082f6343d20..d19325476752 100644
--- a/drivers/gpu/drm/amd/amdgpu/nbio_v7_9.c
+++ b/drivers/gpu/drm/amd/amdgpu/nbio_v7_9.c
@@ -382,7 +382,7 @@ static void nbio_v7_9_enable_doorbell_interrupt(struct amdgpu_device *adev,
 			      DOORBELL_INTERRUPT_DISABLE, enable ? 0 : 1);
 }
 
-static enum amdgpu_gfx_partition nbio_v7_9_get_compute_partition_mode(struct amdgpu_device *adev)
+static int nbio_v7_9_get_compute_partition_mode(struct amdgpu_device *adev)
 {
 	u32 tmp, px;
 
@@ -408,8 +408,8 @@ static void nbio_v7_9_set_compute_partition_mode(struct amdgpu_device *adev,
 	WREG32_SOC15(NBIO, 0, regBIF_BX_PF0_PARTITION_COMPUTE_STATUS, tmp);
 }
 
-static enum amdgpu_memory_partition
-nbio_v7_9_get_memory_partition_mode(struct amdgpu_device *adev, u32 *supp_modes)
+static u32 nbio_v7_9_get_memory_partition_mode(struct amdgpu_device *adev,
+					       u32 *supp_modes)
 {
 	u32 tmp;
 

---
base-commit: fd8f7bb391fa9c1979232cb5ab5bedb08abc855d
change-id: 20230524-nbio_v7_9-wincompatible-function-pointer-types-strict-c894636ce146

Best regards,
-- 
Nathan Chancellor <nathan@kernel.org>

