On 27/03/25 08:03, Dan Williams wrote:
Gustavo A. R. Silva wrote:
-Wflex-array-member-not-at-end was introduced in GCC-14, and we are
getting ready to enable it, globally.

Use the `DEFINE_RAW_FLEX()` helper for on-stack definitions of
a flexible structure where the size of the flexible-array member
is known at compile-time, and refactor the rest of the code,
accordingly.

So, with these changes, fix a dozen of the following warnings:

drivers/acpi/nfit/intel.c:692:35: 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 <[email protected]>
---
Changes in v2:
  - Use DEFINE_RAW_FLEX() instead of __struct_group().

v1:
  - Link: https://lore.kernel.org/linux-hardening/Z618ILbAR8YAvTkd@kspp/

  drivers/acpi/nfit/intel.c | 388 ++++++++++++++++++--------------------
  1 file changed, 179 insertions(+), 209 deletions(-)

diff --git a/drivers/acpi/nfit/intel.c b/drivers/acpi/nfit/intel.c
index 3902759abcba..114d5b3bb39b 100644
--- a/drivers/acpi/nfit/intel.c
+++ b/drivers/acpi/nfit/intel.c
@@ -55,21 +55,17 @@ static unsigned long intel_security_flags(struct nvdimm 
*nvdimm,
  {
        struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
        unsigned long security_flags = 0;
-       struct {
-               struct nd_cmd_pkg pkg;
-               struct nd_intel_get_security_state cmd;
-       } nd_cmd = {
-               .pkg = {
-                       .nd_command = NVDIMM_INTEL_GET_SECURITY_STATE,
-                       .nd_family = NVDIMM_FAMILY_INTEL,
-                       .nd_size_out =
-                               sizeof(struct nd_intel_get_security_state),
-                       .nd_fw_size =
-                               sizeof(struct nd_intel_get_security_state),
-               },
-       };
+       DEFINE_RAW_FLEX(struct nd_cmd_pkg, nd_cmd, nd_payload,
+                       sizeof(struct nd_intel_get_security_state));
+       struct nd_intel_get_security_state *cmd =
+                       (struct nd_intel_get_security_state 
*)nd_cmd->nd_payload;
        int rc;
+ nd_cmd->nd_command = NVDIMM_INTEL_GET_SECURITY_STATE;
+       nd_cmd->nd_family = NVDIMM_FAMILY_INTEL;
+       nd_cmd->nd_size_out = sizeof(struct nd_intel_get_security_state);
+       nd_cmd->nd_fw_size = sizeof(struct nd_intel_get_security_state);

Can this keep the C99 init-style with something like (untested):

_DEFINE_FLEX(struct nd_cmd_pkg, nd_cmd, nd_payload,
              sizeof(struct nd_intel_get_security_state), {
                .pkg = {
                        .nd_command = NVDIMM_INTEL_GET_SECURITY_STATE,
                        .nd_family = NVDIMM_FAMILY_INTEL,
                        .nd_size_out =
                                sizeof(struct nd_intel_get_security_state),
                        .nd_fw_size =
                                sizeof(struct nd_intel_get_security_state),
                },
        });
        

?

The code below works - however, notice that in this case we should
go through 'obj', which is an object defined in _DEFINE_FLEX().

        _DEFINE_FLEX(struct nd_cmd_pkg, nd_cmd, nd_payload,
                        sizeof(struct nd_intel_get_security_state), = {
                .obj = {
                        .nd_command = NVDIMM_INTEL_GET_SECURITY_STATE,
                        .nd_family = NVDIMM_FAMILY_INTEL,
                        .nd_size_out =
                                sizeof(struct nd_intel_get_security_state),
                        .nd_fw_size =
                                sizeof(struct nd_intel_get_security_state),
                },
        });

Thanks
-Gustavo


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