[PATCH] drm/amdgpu: Fix mc_umc_status used uninitialized warning

[Hamza Mahfooz]

On 2022-09-28 10:49, sunpeng.li at amd.com wrote:
> From: Leo Li <sunpeng.li at amd.com>
> 
> On ChromeOS clang build, the following warning is seen:
> 
> /mnt/host/source/src/third_party/kernel/v5.15/drivers/gpu/drm/amd/amdgpu/umc_v6_7.c:463:6: error: variable 'mc_umc_status' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
>          if (mca_addr == UMC_INVALID_ADDR) {
>              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
> /mnt/host/source/src/third_party/kernel/v5.15/drivers/gpu/drm/amd/amdgpu/umc_v6_7.c:485:21: note: uninitialized use occurs here
>          if ((REG_GET_FIELD(mc_umc_status, MCA_UMC_UMC0_MCUMC_STATUST0, Val) == 1 &&
>                             ^~~~~~~~~~~~~
> /mnt/host/source/src/third_party/kernel/v5.15/drivers/gpu/drm/amd/amdgpu/../amdgpu/amdgpu.h:1208:5: note: expanded from macro 'REG_GET_FIELD'
>          (((value) & REG_FIELD_MASK(reg, field)) >> REG_FIELD_SHIFT(reg, field))
>             ^~~~~
> /mnt/host/source/src/third_party/kernel/v5.15/drivers/gpu/drm/amd/amdgpu/umc_v6_7.c:463:2: note: remove the 'if' if its condition is always true
>          if (mca_addr == UMC_INVALID_ADDR) {
>          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> /mnt/host/source/src/third_party/kernel/v5.15/drivers/gpu/drm/amd/amdgpu/umc_v6_7.c:460:24: note: initialize the variable 'mc_umc_status' to silence this warning
>          uint64_t mc_umc_status, mc_umc_addrt0;
>                                ^
>                                 = 0
> 1 error generated.
> make[5]: *** [/mnt/host/source/src/third_party/kernel/v5.15/scripts/Makefile.build:289: drivers/gpu/drm/amd/amdgpu/umc_v6_7.o] Error 1
> 
> Fix by initializing mc_umc_status = 0.
> 
> Fixes: d8e19e32945e ("drm/amdgpu: support to convert dedicated umc mca address")
> Signed-off-by: Leo Li <sunpeng.li at amd.com>

Reviewed-by: Hamza Mahfooz <hamza.mahfooz at amd.com>

> ---
>   drivers/gpu/drm/amd/amdgpu/umc_v6_7.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/umc_v6_7.c b/drivers/gpu/drm/amd/amdgpu/umc_v6_7.c
> index 2cc961534542..a0d19b768346 100644
> --- a/drivers/gpu/drm/amd/amdgpu/umc_v6_7.c
> +++ b/drivers/gpu/drm/amd/amdgpu/umc_v6_7.c
> @@ -457,7 +457,7 @@ static void umc_v6_7_query_error_address(struct amdgpu_device *adev,
>   {
>   	uint32_t mc_umc_status_addr;
>   	uint32_t channel_index;
> -	uint64_t mc_umc_status, mc_umc_addrt0;
> +	uint64_t mc_umc_status = 0, mc_umc_addrt0;
>   	uint64_t err_addr, soc_pa, retired_page, column;
>   
>   	if (mca_addr == UMC_INVALID_ADDR) {

-- 
Hamza