From patchwork Fri Feb 14 00:53:06 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gustavo A. R. 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R. Silva" To: Alison Schofield , Dan Williams , Vishal Verma , Dave Jiang , Ira Weiny , "Rafael J. Wysocki" , Len Brown Cc: nvdimm@lists.linux.dev, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, LIBNVDIMM: ;, NON-VOLATILE MEMORY DEVICE SUBSYSTEM status: ;, SupportedACPI status: "SupportedGustavo A. R. Silva" , linux-hardening@vger.kernel.org; Subject: [PATCH v2][next] UAPI: ndctl / acpi: intel: Avoid multiple -Wflex-array-member-not-at-end warnings Message-ID: Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline -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 flexible-array members in the middle of other structs, we use the `__struct_group()` helper to separate the flexible array from the rest of the members in the flexible structure. We then use the newly created tagged `struct nd_cmd_pkg_hdr` to replace the type of the objects causing trouble: `pkg` in multiple structs. Below is the before-and-after changes of the memory layout in `struct nd_cmd_pkg`. This to illustrate that the use of `__struct_group()` doesn't alter the layout, ensuring that user space remains unaffected. Before changes: struct nd_cmd_pkg { __u64 nd_family; /* 0 8 */ __u64 nd_command; /* 8 8 */ __u32 nd_size_in; /* 16 4 */ __u32 nd_size_out; /* 20 4 */ __u32 nd_reserved2[9]; /* 24 36 */ __u32 nd_fw_size; /* 60 4 */ /* --- cacheline 1 boundary (64 bytes) --- */ unsigned char nd_payload[]; /* 64 0 */ /* size: 64, cachelines: 1, members: 7 */ }; After changes: struct nd_cmd_pkg { union { struct { __u64 nd_family; /* 0 8 */ __u64 nd_command; /* 8 8 */ __u32 nd_size_in; /* 16 4 */ __u32 nd_size_out; /* 20 4 */ __u32 nd_reserved2[9]; /* 24 36 */ __u32 nd_fw_size; /* 60 4 */ }; /* 0 64 */ struct nd_cmd_pkg_hdr __hdr; /* 0 64 */ }; /* 0 64 */ /* --- cacheline 1 boundary (64 bytes) --- */ unsigned char nd_payload[]; /* 64 0 */ /* size: 64, cachelines: 1, members: 2 */ }; It's also worth mentioning that all members of the struct can still be accessed directly, for example instance->nd_family, instance->nd_command, and so on. So, with these changes, fix 12 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 Reviewed-by: Alison Schofield Reviewed-by: Dave Jiang --- Changes in v2: - Show changes in UAPI first. (Alison) - Update changelog text --add more information about _struct_group() changes. (Alison) v1: - Link: https://lore.kernel.org/linux-hardening/Z618ILbAR8YAvTkd@kspp/ include/uapi/linux/ndctl.h | 15 +++++++++------ drivers/acpi/nfit/intel.c | 24 ++++++++++++------------ 2 files changed, 21 insertions(+), 18 deletions(-) diff --git a/include/uapi/linux/ndctl.h b/include/uapi/linux/ndctl.h index 73516e263627..34c11644d5d7 100644 --- a/include/uapi/linux/ndctl.h +++ b/include/uapi/linux/ndctl.h @@ -227,12 +227,15 @@ enum ars_masks { */ struct nd_cmd_pkg { - __u64 nd_family; /* family of commands */ - __u64 nd_command; - __u32 nd_size_in; /* INPUT: size of input args */ - __u32 nd_size_out; /* INPUT: size of payload */ - __u32 nd_reserved2[9]; /* reserved must be zero */ - __u32 nd_fw_size; /* OUTPUT: size fw wants to return */ + /* New members MUST be added within the __struct_group() macro below. */ + __struct_group(nd_cmd_pkg_hdr, __hdr, /* no attrs */, + __u64 nd_family; /* family of commands */ + __u64 nd_command; + __u32 nd_size_in; /* INPUT: size of input args */ + __u32 nd_size_out; /* INPUT: size of payload */ + __u32 nd_reserved2[9]; /* reserved must be zero */ + __u32 nd_fw_size; /* OUTPUT: size fw wants to return */ + ); unsigned char nd_payload[]; /* Contents of call */ }; diff --git a/drivers/acpi/nfit/intel.c b/drivers/acpi/nfit/intel.c index 3902759abcba..fe561ce0ddec 100644 --- a/drivers/acpi/nfit/intel.c +++ b/drivers/acpi/nfit/intel.c @@ -56,7 +56,7 @@ 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_cmd_pkg_hdr pkg; struct nd_intel_get_security_state cmd; } nd_cmd = { .pkg = { @@ -121,7 +121,7 @@ static int intel_security_freeze(struct nvdimm *nvdimm) { struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm); struct { - struct nd_cmd_pkg pkg; + struct nd_cmd_pkg_hdr pkg; struct nd_intel_freeze_lock cmd; } nd_cmd = { .pkg = { @@ -154,7 +154,7 @@ static int intel_security_change_key(struct nvdimm *nvdimm, NVDIMM_INTEL_SET_MASTER_PASSPHRASE : NVDIMM_INTEL_SET_PASSPHRASE; struct { - struct nd_cmd_pkg pkg; + struct nd_cmd_pkg_hdr pkg; struct nd_intel_set_passphrase cmd; } nd_cmd = { .pkg = { @@ -196,7 +196,7 @@ static int __maybe_unused intel_security_unlock(struct nvdimm *nvdimm, { struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm); struct { - struct nd_cmd_pkg pkg; + struct nd_cmd_pkg_hdr pkg; struct nd_intel_unlock_unit cmd; } nd_cmd = { .pkg = { @@ -235,7 +235,7 @@ static int intel_security_disable(struct nvdimm *nvdimm, int rc; struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm); struct { - struct nd_cmd_pkg pkg; + struct nd_cmd_pkg_hdr pkg; struct nd_intel_disable_passphrase cmd; } nd_cmd = { .pkg = { @@ -278,7 +278,7 @@ static int __maybe_unused intel_security_erase(struct nvdimm *nvdimm, unsigned int cmd = ptype == NVDIMM_MASTER ? NVDIMM_INTEL_MASTER_SECURE_ERASE : NVDIMM_INTEL_SECURE_ERASE; struct { - struct nd_cmd_pkg pkg; + struct nd_cmd_pkg_hdr pkg; struct nd_intel_secure_erase cmd; } nd_cmd = { .pkg = { @@ -319,7 +319,7 @@ static int __maybe_unused intel_security_query_overwrite(struct nvdimm *nvdimm) int rc; struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm); struct { - struct nd_cmd_pkg pkg; + struct nd_cmd_pkg_hdr pkg; struct nd_intel_query_overwrite cmd; } nd_cmd = { .pkg = { @@ -355,7 +355,7 @@ static int __maybe_unused intel_security_overwrite(struct nvdimm *nvdimm, int rc; struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm); struct { - struct nd_cmd_pkg pkg; + struct nd_cmd_pkg_hdr pkg; struct nd_intel_overwrite cmd; } nd_cmd = { .pkg = { @@ -408,7 +408,7 @@ static int intel_bus_fwa_businfo(struct nvdimm_bus_descriptor *nd_desc, struct nd_intel_bus_fw_activate_businfo *info) { struct { - struct nd_cmd_pkg pkg; + struct nd_cmd_pkg_hdr pkg; struct nd_intel_bus_fw_activate_businfo cmd; } nd_cmd = { .pkg = { @@ -519,7 +519,7 @@ static int intel_bus_fwa_activate(struct nvdimm_bus_descriptor *nd_desc) { struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc); struct { - struct nd_cmd_pkg pkg; + struct nd_cmd_pkg_hdr pkg; struct nd_intel_bus_fw_activate cmd; } nd_cmd = { .pkg = { @@ -583,7 +583,7 @@ static int intel_fwa_dimminfo(struct nvdimm *nvdimm, struct nd_intel_fw_activate_dimminfo *info) { struct { - struct nd_cmd_pkg pkg; + struct nd_cmd_pkg_hdr pkg; struct nd_intel_fw_activate_dimminfo cmd; } nd_cmd = { .pkg = { @@ -689,7 +689,7 @@ static int intel_fwa_arm(struct nvdimm *nvdimm, enum nvdimm_fwa_trigger arm) struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm); struct acpi_nfit_desc *acpi_desc = nfit_mem->acpi_desc; struct { - struct nd_cmd_pkg pkg; + struct nd_cmd_pkg_hdr pkg; struct nd_intel_fw_activate_arm cmd; } nd_cmd = { .pkg = {