On Wed, Feb 10, 2021 at 6:49 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].
Use flexible-array member in struct NISLANDS_SMC_SWSTATE, instead of one-element array.
Also, this helps with the ongoing efforts to enable -Warray-bounds by fixing the following warnings:
drivers/gpu/drm/radeon/ni_dpm.c: In function ‘ni_convert_power_state_to_smc’: drivers/gpu/drm/radeon/ni_dpm.c:2521:20: warning: array subscript 1 is above array bounds of ‘NISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’ {aka ‘struct NISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’} [-Warray-bounds] 2521 | smc_state->levels[i].dpm2.MaxPS = | ~~~~~~~~~~~~~~~~~^~~ drivers/gpu/drm/radeon/ni_dpm.c:2523:20: warning: array subscript 1 is above array bounds of ‘NISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’ {aka ‘struct NISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’} [-Warray-bounds] 2523 | smc_state->levels[i].dpm2.NearTDPDec = NISLANDS_DPM2_NEAR_TDP_DEC; | ~~~~~~~~~~~~~~~~~^~~ drivers/gpu/drm/radeon/ni_dpm.c:2524:20: warning: array subscript 1 is above array bounds of ‘NISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’ {aka ‘struct NISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’} [-Warray-bounds] 2524 | smc_state->levels[i].dpm2.AboveSafeInc = NISLANDS_DPM2_ABOVE_SAFE_INC; | ~~~~~~~~~~~~~~~~~^~~ drivers/gpu/drm/radeon/ni_dpm.c:2525:20: warning: array subscript 1 is above array bounds of ‘NISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’ {aka ‘struct NISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’} [-Warray-bounds] 2525 | smc_state->levels[i].dpm2.BelowSafeInc = NISLANDS_DPM2_BELOW_SAFE_INC; | ~~~~~~~~~~~~~~~~~^~~ drivers/gpu/drm/radeon/ni_dpm.c:2526:35: warning: array subscript 1 is above array bounds of ‘NISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’ {aka ‘struct NISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’} [-Warray-bounds] 2526 | smc_state->levels[i].stateFlags |= | ^~ drivers/gpu/drm/radeon/ni_dpm.c:2526:35: warning: array subscript 1 is above array bounds of ‘NISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’ {aka ‘struct NISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’} [-Warray-bounds] 2526 | smc_state->levels[i].stateFlags |= | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~ 2527 | ((i != (state->performance_level_count - 1)) && power_boost_limit) ? | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 2528 | PPSMC_STATEFLAG_POWERBOOST : 0; | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/radeon/ni_dpm.c:2442:20: warning: array subscript 1 is above array bounds of ‘NISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’ {aka ‘struct NISLANDS_SMC_HW_PERFORMANCE_LEVEL[1]’} [-Warray-bounds] 2442 | smc_state->levels[i + 1].aT = cpu_to_be32(a_t);
[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/6023ed54.BfIY+9Uz81I6nq19%25lkp@intel.com/ Signed-off-by: Gustavo A. R. Silva gustavoars@kernel.org
Applied. Thanks!
Alex
drivers/gpu/drm/radeon/nislands_smc.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/radeon/nislands_smc.h b/drivers/gpu/drm/radeon/nislands_smc.h index 3cf8fc0d83f4..7395cb6b3cac 100644 --- a/drivers/gpu/drm/radeon/nislands_smc.h +++ b/drivers/gpu/drm/radeon/nislands_smc.h @@ -134,11 +134,11 @@ typedef struct NISLANDS_SMC_HW_PERFORMANCE_LEVEL NISLANDS_SMC_HW_PERFORMANCE_LEV
struct NISLANDS_SMC_SWSTATE {
- uint8_t flags;
- uint8_t levelCount;
- uint8_t padding2;
- uint8_t padding3;
- NISLANDS_SMC_HW_PERFORMANCE_LEVEL levels[1];
uint8_t flags;uint8_t levelCount;uint8_t padding2;uint8_t padding3;NISLANDS_SMC_HW_PERFORMANCE_LEVEL levels[];};
typedef struct NISLANDS_SMC_SWSTATE NISLANDS_SMC_SWSTATE;
2.27.0
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