-Wflex-array-member-not-at-end was introduced in GCC-14, and we are
getting ready to enable it, globally.
So, in order to avoid ending up with a flexible-array member in the
middle of other structs, we use the `struct_group_tagged()` helper
to create a new tagged `struct NISLANDS_SMC_SWSTATE_HDR` (and `struct
SISLANDS_SMC_SWSTATE_HDR`). This structures group together all the
members of the flexible `struct NISLANDS_SMC_SWSTATE` (and `struct
SISLANDS_SMC_SWSTATE`) except the flexible array.
As a result, the array is effectively separated from the rest of the
members without modifying the memory layout of the flexible structure.
We then change the type of the middle struct members currently causing
trouble from `struct NISLANDS_SMC_SWSTATE` to `struct
NISLANDS_SMC_SWSTATE_HDR` (and from `struct SISLANDS_SMC_SWSTATE` to
`struct SISLANDS_SMC_SWSTATE_HDR`).
We also want to ensure that when new members need to be added to the
flexible structure, they are always included within the newly created
tagged struct. For this, we use `static_assert()`. This ensures that
the memory layout for both the flexible structure and the new tagged
struct is the same after any changes.
This approach avoids having to implement `struct NISLANDS_SMC_SWSTATE_HDR`
(and `struct SISLANDS_SMC_SWSTATE_HDR`) as a completely separate structure,
thus preventing having to maintain two independent but basically identical
structures, closing the door to potential bugs in the future.
We also use `container_of()` whenever we need to retrieve a pointer to
the flexible structure, through which we can access the flexible-array
member, if necessary.
So, with this changes, fix the following warnings:
drivers/gpu/drm/amd/amdgpu/../pm/legacy-dpm/sislands_smc.h:218:49: warning:
structure containing a flexible array member is not at the end of another
structure [-Wflex-array-member-not-at-end]
drivers/gpu/drm/amd/amdgpu/../pm/legacy-dpm/si_dpm.h:819:41: warning: structure
containing a flexible array member is not at the end of another structure
[-Wflex-array-member-not-at-end]
drivers/gpu/drm/amd/amdgpu/../pm/legacy-dpm/si_dpm.h:818:41: warning: structure
containing a flexible array member is not at the end of another structure
[-Wflex-array-member-not-at-end]
drivers/gpu/drm/amd/amdgpu/../pm/legacy-dpm/si_dpm.h:817:41: warning: structure
containing a flexible array member is not at the end of another structure
[-Wflex-array-member-not-at-end]
drivers/gpu/drm/amd/amdgpu/../pm/legacy-dpm/si_dpm.h:816:41: warning: structure
containing a flexible array member is not at the end of another structure
[-Wflex-array-member-not-at-end]
Signed-off-by: Gustavo A. R. Silva <gustavo...@kernel.org>
---
drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.c | 7 ++++--
drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.h | 23 +++++++++++--------
.../gpu/drm/amd/pm/legacy-dpm/sislands_smc.h | 15 ++++++++----
3 files changed, 29 insertions(+), 16 deletions(-)
diff --git a/drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.c
b/drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.c
index a87dcf0974bc..2c9d473d122f 100644
--- a/drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.c
+++ b/drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.c
@@ -5234,7 +5234,8 @@ static int si_init_smc_table(struct amdgpu_device *adev)
table->driverState.flags = table->initialState.flags;
table->driverState.levelCount = table->initialState.levelCount;
- table->driverState.levels[0] = table->initialState.level;
+ container_of(&table->driverState, SISLANDS_SMC_SWSTATE,
__hdr)->levels[0] =
+
table->initialState.level;
ret = si_do_program_memory_timing_parameters(adev, amdgpu_boot_state,
SISLANDS_INITIAL_STATE_ARB_INDEX);
@@ -5755,7 +5756,9 @@ static int si_upload_sw_state(struct amdgpu_device *adev,
int ret;
u32 address = si_pi->state_table_start +
offsetof(SISLANDS_SMC_STATETABLE, driverState);
- SISLANDS_SMC_SWSTATE *smc_state = &si_pi->smc_statetable.driverState;
+ SISLANDS_SMC_SWSTATE *smc_state =
+ container_of(&si_pi->smc_statetable.driverState,
+ SISLANDS_SMC_SWSTATE, __hdr);
size_t state_size = struct_size(smc_state, levels,
new_state->performance_level_count);
memset(smc_state, 0, state_size);
diff --git a/drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.h
b/drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.h
index 11cb7874a6bb..62530f89ebdf 100644
--- a/drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.h
+++ b/drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.h
@@ -784,12 +784,17 @@ 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[];
+ /* New members MUST be added within the struct_group() macro below. */
+ struct_group_tagged(NISLANDS_SMC_SWSTATE_HDR, __hdr,
+ uint8_t flags;
+ uint8_t levelCount;
+ uint8_t padding2;
+ uint8_t padding3;
+ );
+ NISLANDS_SMC_HW_PERFORMANCE_LEVEL levels[];
};
+static_assert(offsetof(struct NISLANDS_SMC_SWSTATE, levels) == sizeof(struct
NISLANDS_SMC_SWSTATE_HDR),
+ "struct member likely outside of struct_group_tagged()");
typedef struct NISLANDS_SMC_SWSTATE NISLANDS_SMC_SWSTATE;
@@ -813,10 +818,10 @@ struct NISLANDS_SMC_STATETABLE
uint32_t lowSMIO[NISLANDS_MAX_NO_VREG_STEPS];
NISLANDS_SMC_VOLTAGEMASKTABLE voltageMaskTable;
PP_NIslands_DPM2Parameters dpm2Params;
- NISLANDS_SMC_SWSTATE initialState;
- NISLANDS_SMC_SWSTATE ACPIState;
- NISLANDS_SMC_SWSTATE ULVState;
- NISLANDS_SMC_SWSTATE driverState;
+ struct NISLANDS_SMC_SWSTATE_HDR initialState;
+ struct NISLANDS_SMC_SWSTATE_HDR ACPIState;
+ struct NISLANDS_SMC_SWSTATE_HDR ULVState;
+ struct NISLANDS_SMC_SWSTATE_HDR driverState;
NISLANDS_SMC_HW_PERFORMANCE_LEVEL
dpmLevels[NISLANDS_MAX_SMC_PERFORMANCE_LEVELS_PER_SWSTATE - 1];
};
diff --git a/drivers/gpu/drm/amd/pm/legacy-dpm/sislands_smc.h
b/drivers/gpu/drm/amd/pm/legacy-dpm/sislands_smc.h
index 90ec411c5029..1711e3e35e80 100644
--- a/drivers/gpu/drm/amd/pm/legacy-dpm/sislands_smc.h
+++ b/drivers/gpu/drm/amd/pm/legacy-dpm/sislands_smc.h
@@ -172,12 +172,17 @@ struct SISLANDS_SMC_HW_PERFORMANCE_LEVEL {
typedef struct SISLANDS_SMC_HW_PERFORMANCE_LEVEL
SISLANDS_SMC_HW_PERFORMANCE_LEVEL;
struct SISLANDS_SMC_SWSTATE {
- uint8_t flags;
- uint8_t levelCount;
- uint8_t padding2;
- uint8_t padding3;
+ /* New members MUST be added within the struct_group() macro below. */
+ struct_group_tagged(SISLANDS_SMC_SWSTATE_HDR, __hdr,
+ uint8_t flags;
+ uint8_t levelCount;
+ uint8_t padding2;
+ uint8_t padding3;
+ );
SISLANDS_SMC_HW_PERFORMANCE_LEVEL levels[];
};
+static_assert(offsetof(struct SISLANDS_SMC_SWSTATE, levels) == sizeof(struct
SISLANDS_SMC_SWSTATE_HDR),
+ "struct member likely outside of struct_group_tagged()");
typedef struct SISLANDS_SMC_SWSTATE SISLANDS_SMC_SWSTATE;
@@ -215,7 +220,7 @@ struct SISLANDS_SMC_STATETABLE {
struct SISLANDS_SMC_SWSTATE_SINGLE initialState;
struct SISLANDS_SMC_SWSTATE_SINGLE ACPIState;
struct SISLANDS_SMC_SWSTATE_SINGLE ULVState;
- SISLANDS_SMC_SWSTATE driverState;
+ struct SISLANDS_SMC_SWSTATE_HDR driverState;
SISLANDS_SMC_HW_PERFORMANCE_LEVEL
dpmLevels[SISLANDS_MAX_SMC_PERFORMANCE_LEVELS_PER_SWSTATE];
};
--
2.43.0
