| From 7f85f7bbd559e50b83928437e5c544a8218e3a5d Mon Sep 17 00:00:00 2001 |
| From: Nathan Chancellor <natechancellor@gmail.com> |
| Date: Sat, 23 Nov 2019 12:23:36 -0700 |
| Subject: [PATCH] drm/amdgpu: Ensure ret is always initialized when using |
| SOC15_WAIT_ON_RREG |
| |
| commit a63141e31764f8daf3f29e8e2d450dcf9199d1c8 upstream. |
| |
| Commit b0f3cd3191cd ("drm/amdgpu: remove unnecessary JPEG2.0 code from |
| VCN2.0") introduced a new clang warning in the vcn_v2_0_stop function: |
| |
| ../drivers/gpu/drm/amd/amdgpu/vcn_v2_0.c:1082:2: warning: variable 'r' |
| is used uninitialized whenever 'while' loop exits because its condition |
| is false [-Wsometimes-uninitialized] |
| SOC15_WAIT_ON_RREG(VCN, 0, mmUVD_STATUS, UVD_STATUS__IDLE, 0x7, r); |
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| ../drivers/gpu/drm/amd/amdgpu/../amdgpu/soc15_common.h:55:10: note: |
| expanded from macro 'SOC15_WAIT_ON_RREG' |
| while ((tmp_ & (mask)) != (expected_value)) { \ |
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| ../drivers/gpu/drm/amd/amdgpu/vcn_v2_0.c:1083:6: note: uninitialized use |
| occurs here |
| if (r) |
| ^ |
| ../drivers/gpu/drm/amd/amdgpu/vcn_v2_0.c:1082:2: note: remove the |
| condition if it is always true |
| SOC15_WAIT_ON_RREG(VCN, 0, mmUVD_STATUS, UVD_STATUS__IDLE, 0x7, r); |
| ^ |
| ../drivers/gpu/drm/amd/amdgpu/../amdgpu/soc15_common.h:55:10: note: |
| expanded from macro 'SOC15_WAIT_ON_RREG' |
| while ((tmp_ & (mask)) != (expected_value)) { \ |
| ^ |
| ../drivers/gpu/drm/amd/amdgpu/vcn_v2_0.c:1072:7: note: initialize the |
| variable 'r' to silence this warning |
| int r; |
| ^ |
| = 0 |
| 1 warning generated. |
| |
| To prevent warnings like this from happening in the future, make the |
| SOC15_WAIT_ON_RREG macro initialize its ret variable before the while |
| loop that can time out. This macro's return value is always checked so |
| it should set ret in both the success and fail path. |
| |
| Link: https://github.com/ClangBuiltLinux/linux/issues/776 |
| Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> |
| Signed-off-by: Alex Deucher <alexander.deucher@amd.com> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/drivers/gpu/drm/amd/amdgpu/soc15_common.h b/drivers/gpu/drm/amd/amdgpu/soc15_common.h |
| index 49c262540940..55cde43d9b62 100644 |
| --- a/drivers/gpu/drm/amd/amdgpu/soc15_common.h |
| +++ b/drivers/gpu/drm/amd/amdgpu/soc15_common.h |
| @@ -52,6 +52,7 @@ |
| uint32_t old_ = 0; \ |
| uint32_t tmp_ = RREG32(adev->reg_offset[ip##_HWIP][inst][reg##_BASE_IDX] + reg); \ |
| uint32_t loop = adev->usec_timeout; \ |
| + ret = 0; \ |
| while ((tmp_ & (mask)) != (expected_value)) { \ |
| if (old_ != tmp_) { \ |
| loop = adev->usec_timeout; \ |
| -- |
| 2.7.4 |
| |