drm/amdgpu: Initialize data to NULL in imu_v12_0_program_rlc_ram()

commit c90f2e1172c51fa25492471dc9910e2d7c1444b9 upstream.

After a recent change in clang to expose uninitialized warnings from
const variables and pointers [1], there is a warning in
imu_v12_0_program_rlc_ram() because data is passed uninitialized to
program_imu_rlc_ram():

  drivers/gpu/drm/amd/amdgpu/imu_v12_0.c:374:30: error: variable 'data' is uninitialized when used here [-Werror,-Wuninitialized]
    374 |                         program_imu_rlc_ram(adev, data, (const u32)size);
        |                                                   ^~~~

As this warning happens early in clang's frontend, it does not realize
that due to the assignment of r to -EINVAL, program_imu_rlc_ram() is
never actually called, and even if it were, data would not be
dereferenced because size is 0.

Just initialize data to NULL to silence the warning, as the commit that
added program_imu_rlc_ram() mentioned it would eventually be used over
the old method, at which point data can be properly initialized and
used.

Cc: stable@vger.kernel.org
Closes: https://github.com/ClangBuiltLinux/linux/issues/2107
Fixes: 56159fffaab5 ("drm/amdgpu: use new method to program rlc ram")
Link: https://github.com/llvm/llvm-project/commit/2464313eef01c5b1edf0eccf57a32cdee01472c7
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/amd/amdgpu/imu_v12_0.c b/drivers/gpu/drm/amd/amdgpu/imu_v12_0.c
index d9a05d1c60abc91428bee5f0f39fddc909a3df1d..58cd87db80619fbf4ab809cddc15c7465d3e746e 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/imu_v12_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/imu_v12_0.c
@@ -367,7 +367,7 @@ static void program_imu_rlc_ram(struct amdgpu_device *adev,
 static void imu_v12_0_program_rlc_ram(struct amdgpu_device *adev)
 {
        u32 reg_data, size = 0;
-       const u32 *data;
+       const u32 *data = NULL;
        int r = -EINVAL;
 
        WREG32_SOC15(GC, 0, regGFX_IMU_RLC_RAM_INDEX, 0x2);