On Wed, Feb 10, 2021 at 5:40 PM Gustavo A. R. Silva gustavoars@kernel.org wrote:

There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2].

Refactor the code according to the use of a flexible-array member in struct SISLANDS_SMC_SWSTATE, instead of a one-element array, and use the struct_size() helper to calculate the size for the allocation.

Also, this helps with the ongoing efforts to enable -Warray-bounds and fix the following warnings:

drivers/gpu/drm/amd/amdgpu/../pm/powerplay/si_dpm.c:2448:20: warning: array subscript 1 is above array bounds of ‘SISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’ {aka ‘struct SISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’} [-Warray-bounds] drivers/gpu/drm/amd/amdgpu/../pm/powerplay/si_dpm.c:2449:20: warning: array subscript 1 is above array bounds of ‘SISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’ {aka ‘struct SISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’} [-Warray-bounds] drivers/gpu/drm/amd/amdgpu/../pm/powerplay/si_dpm.c:2450:20: warning: array subscript 1 is above array bounds of ‘SISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’ {aka ‘struct SISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’} [-Warray-bounds] drivers/gpu/drm/amd/amdgpu/../pm/powerplay/si_dpm.c:2451:20: warning: array subscript 1 is above array bounds of ‘SISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’ {aka ‘struct SISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’} [-Warray-bounds] drivers/gpu/drm/amd/amdgpu/../pm/powerplay/si_dpm.c:2452:20: warning: array subscript 1 is above array bounds of ‘SISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’ {aka ‘struct SISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’} [-Warray-bounds] drivers/gpu/drm/amd/amdgpu/../pm/powerplay/si_dpm.c:5570:20: warning: array subscript 1 is above array bounds of ‘SISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’ {aka ‘struct SISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’} [-Warray-bounds]

[1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://www.kernel.org/doc/html/v5.9/process/deprecated.html#zero-length-and...

Link: https://github.com/KSPP/linux/issues/79 Link: https://github.com/KSPP/linux/issues/109 Build-tested-by: kernel test robot lkp@intel.com Link: https://lore.kernel.org/lkml/6023be58.sk66L%2FV4vuSJI5mI%25lkp@intel.com/ Signed-off-by: Gustavo A. R. Silva gustavoars@kernel.org

Applied. Thanks!

Alex

---

drivers/gpu/drm/amd/pm/powerplay/si_dpm.c | 6 ++---- drivers/gpu/drm/amd/pm/powerplay/sislands_smc.h | 10 +++++----- 2 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/amd/pm/powerplay/si_dpm.c b/drivers/gpu/drm/amd/pm/powerplay/si_dpm.c index afa1711c9620..62291358fb1c 100644 --- a/drivers/gpu/drm/amd/pm/powerplay/si_dpm.c +++ b/drivers/gpu/drm/amd/pm/powerplay/si_dpm.c @@ -5715,11 +5715,9 @@ static int si_upload_sw_state(struct amdgpu_device *adev, int ret; u32 address = si_pi->state_table_start + offsetof(SISLANDS_SMC_STATETABLE, driverState);

•   u32 state_size = sizeof(SISLANDS_SMC_SWSTATE) +
  

•           ((new_state->performance_level_count - 1) *
  

•            sizeof(SISLANDS_SMC_HW_PERFORMANCE_LEVEL));
    SISLANDS_SMC_SWSTATE *smc_state = &si_pi->smc_statetable.driverState;
  

•   size_t state_size = struct_size(smc_state, levels,
  

•                                   new_state->performance_level_count);
    memset(smc_state, 0, state_size);
  
    ret = si_convert_power_state_to_smc(adev, amdgpu_new_state, smc_state);
  

diff --git a/drivers/gpu/drm/amd/pm/powerplay/sislands_smc.h b/drivers/gpu/drm/amd/pm/powerplay/sislands_smc.h index d2930eceaf3c..0f7554052c90 100644 --- a/drivers/gpu/drm/amd/pm/powerplay/sislands_smc.h +++ b/drivers/gpu/drm/amd/pm/powerplay/sislands_smc.h @@ -182,11 +182,11 @@ typedef struct SISLANDS_SMC_HW_PERFORMANCE_LEVEL SISLANDS_SMC_HW_PERFORMANCE_LEV

struct SISLANDS_SMC_SWSTATE {

• uint8_t flags;
• uint8_t levelCount;
• uint8_t padding2;
• uint8_t padding3;
• SISLANDS_SMC_HW_PERFORMANCE_LEVEL levels[1];

•   uint8_t                             flags;
  

•   uint8_t                             levelCount;
  

•   uint8_t                             padding2;
  

•   uint8_t                             padding3;
  

•   SISLANDS_SMC_HW_PERFORMANCE_LEVEL   levels[];
  

};

typedef struct SISLANDS_SMC_SWSTATE SISLANDS_SMC_SWSTATE;

2.27.0

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