On Thu, Oct 17, 2019 at 09:09:01PM +0200, Ard Biesheuvel wrote:
> +void hchacha_block_arch(const u32 *state, u32 *stream, int nrounds)
> +{
> + state = PTR_ALIGN(state, CHACHA_STATE_ALIGN);
> +
> + if (!static_branch_likely(&chacha_use_simd) || !crypto_simd_usable()) {
> + hchacha_block_generic(state, stream, nrounds);
> + } else {
> + kernel_fpu_begin();
> + hchacha_block_ssse3(state, stream, nrounds);
> + kernel_fpu_end();
> + }
> +}
> +EXPORT_SYMBOL(hchacha_block_arch);
I generally find negative logic like the above harder to read than the other
way:
if (static_branch_likely(&chacha_use_simd) && crypto_simd_usable()) {
kernel_fpu_begin();
hchacha_block_ssse3(state, stream, nrounds);
kernel_fpu_end();
} else {
hchacha_block_generic(state, stream, nrounds);
}
(This applies to lots of places in this patch series.) Not a big deal though.
> static int __init chacha_simd_mod_init(void)
> {
> if (!boot_cpu_has(X86_FEATURE_SSSE3))
> - return -ENODEV;
> -
> -#ifdef CONFIG_AS_AVX2
> - chacha_use_avx2 = boot_cpu_has(X86_FEATURE_AVX) &&
> - boot_cpu_has(X86_FEATURE_AVX2) &&
> - cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL);
> -#ifdef CONFIG_AS_AVX512
> - chacha_use_avx512vl = chacha_use_avx2 &&
> - boot_cpu_has(X86_FEATURE_AVX512VL) &&
> - boot_cpu_has(X86_FEATURE_AVX512BW); /* kmovq */
> -#endif
> -#endif
> + return 0;
> +
> + static_branch_enable(&chacha_use_simd);
> +
> + if (IS_ENABLED(CONFIG_AS_AVX2) &&
> + boot_cpu_has(X86_FEATURE_AVX) &&
> + boot_cpu_has(X86_FEATURE_AVX2) &&
> + cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL)) {
> + static_branch_enable(&chacha_use_avx2);
> +
> + if (IS_ENABLED(CONFIG_AS_AVX512) &&
> + boot_cpu_has(X86_FEATURE_AVX512VL) &&
> + boot_cpu_has(X86_FEATURE_AVX512BW)) /* kmovq */
> + static_branch_enable(&chacha_use_avx512vl);
> + }
> return crypto_register_skciphers(algs, ARRAY_SIZE(algs));
> }
>
This patch is missing the corresponding change to chacha_simd_mod_fini(), to
skip unregistering the skcipher algorithms if they weren't registered.
- Eric
