[danielinux]

The file-local cpuid_flags statics in sha3.c, wc_frodokem_mat.c, wc_mlkem_poly.c and wc_mldsa.c start out as WC_CPUID_INITIALIZER, which is all ones. Any dispatch read before cpuid_get_flags_ex() therefore reports every feature present and sends a CPU without the extension into the asm path, where it dies with SIGILL.

The dispatchers assume a prior key init set the flags, but the unit tests and white-box harnesses call them directly, without wc_MlDsaKey_Init() (and friends). On a CPU without AVX-512 this crashed the ML-DSA white-box harness in wc_mldsa_make_hint_88_avx512.

aes.c already carries this pattern: a lazy init check before the dispatch. Add the same guard here - every dispatch now reads the flags through a per-file helper that resolves the sentinel on first use, so a read before any init reports no features and takes the C fallback instead of trapping.

Verification: configure --enable-intelasm, full testwolfcrypt KAT suite passes (ML-DSA, ML-KEM, FrodoKEM, SHA-3), unit test groups mldsa/mlkem/frodokem/sha3 all pass; the ML-DSA AVX2 white-box harness that SIGILL'd before now runs to completion.

[github-actions]

MemBrowse Memory Report · Explore what changed →

zephyr-frdm_rw612

• FLASH: log_const_area -8 B, rodata -8 B, text +1,592 B (+0.6%, 284,040 B / 67,108,864 B, total: 0% used)

No memory changes detected for:

• gcc-arm-cortex-m0plus
• gcc-arm-cortex-m3
• gcc-arm-cortex-m4
• gcc-arm-cortex-m4-baremetal
• gcc-arm-cortex-m4-crypto-only
• gcc-arm-cortex-m4-dtls13
• gcc-arm-cortex-m4-min-ecc
• gcc-arm-cortex-m4-openssl-compat
• gcc-arm-cortex-m4-pkcs7
• gcc-arm-cortex-m4-pq
• gcc-arm-cortex-m4-rsa-only
• gcc-arm-cortex-m4-sp-math
• gcc-arm-cortex-m4-tls12
• gcc-arm-cortex-m4-tls13
• gcc-arm-cortex-m7
• gcc-arm-cortex-m7-pq
• gcc-arm-cortex-m7-tls13
• stm32-sim-stm32h753

---

_{Catch memory regressions in CI with MemBrowse. Free for open source.}

[Copilot]

🟡 Changes recommended

Three critical AArch64 configurations can emit unused static ARM helper functions, causing builds with -Werror=unused-function to fail unless their definitions are guarded consistently with their call sites.

3 open issues

• Guard unused SHA-3 helper definition by its feature conditions · New
• Guard ARM dispatch helper when all call sites are disabled · New
• Guard ARM dispatch helper when all call sites are disabled · New

What changed in this PR

This pull request makes SHA-3, ML-KEM, ML-DSA, and FrodoKEM CPU-feature dispatch safe when file-local CPUID flags remain at the all-ones sentinel, preventing unsupported assembly paths and potential SIGILL failures during direct or white-box calls.

Changes:

• Added per-file lazy CPUID resolution helpers.
• Routed optimized Intel and AArch64 dispatch decisions through the resolved flags.
• Preserved explicit initialization paths while enabling safe C fallbacks before initialization.

File	Summary	Review findings
wolfcrypt/​src/​wc_mlkem_poly.c	Adds lazy CPUID resolution for ML-KEM SIMD and AArch64 dispatches.	Critical (1 vote): The helper may be emitted without any compiled call sites under default AArch64 configurations, causing -Werror=unused-function build failures.
wolfcrypt/​src/​wc_mldsa.c	Adds lazy CPUID resolution across ML-DSA hashing, vector, arithmetic, and hint dispatches.	Critical (1 vote): The helper may be emitted without any compiled call sites under default AArch64 configurations, causing -Werror=unused-function build failures.
wolfcrypt/​src/​wc_frodokem_mat.c	Guards FrodoKEM SIMD, SHA-3, AES, SVE, and SME dispatches against the sentinel.	No review findings.
wolfcrypt/​src/​sha3.c	Adds guarded CPUID resolution for SHA-3 implementation selection.	Critical (1 vote): The helper may be emitted without any compiled call sites on AArch64 configurations lacking the SHA-3 crypto extension, causing -Werror=unused-function build failures.

_{Review effort: Lite}

[wolfSSL-Fenrir-bot]

Fenrir Automated Review — PR #12039

Scan targets checked: wolfcrypt-src, wolfcrypt-bugs
Coverage: 4 of 4 in-scope changed file(s) opened by the reviewer

Fenrir result: Approved ✅

No new issues found in the changed files.

Advisory only — this automated result does not count as a GitHub approval.

Review tier: Max