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SubjectRe: [PATCH] crypto: serpent - add x86_64/avx assembler implementation
Date
Johannes Goetzfried
<Johannes.Goetzfried@informatik.stud.uni-erlangen.de> writes:
> +
> +static int __init serpent_init(void)
> +{
> + u64 xcr0;
> +
> + if (!cpu_has_avx || !cpu_has_osxsave) {
> + printk(KERN_INFO "AVX instructions are not detected.\n");
> + return -ENODEV;
> + }
> +
> + xcr0 = xgetbv(XCR_XFEATURE_ENABLED_MASK);
> + if ((xcr0 & (XSTATE_SSE | XSTATE_YMM)) != (XSTATE_SSE | XSTATE_YMM)) {
> + printk(KERN_INFO "AVX detected but unusable.\n");
> + return -ENODEV;
> + }
> +
> + return crypto_register_algs(serpent_algs, ARRAY_SIZE(serpent_algs));
> +}
> +
> +static void __exit serpent_exit(void)
> +{
> + crypto_unregister_algs(serpent_algs, ARRAY_SIZE(serpent_algs));
> +}
> +
> +module_init(serpent_init);
> +module_exit(serpent_exit);
> +
> +MODULE_DESCRIPTION("Serpent Cipher Algorithm, AVX optimized");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("serpent");

The driver needs CPUID annotations now (since 3.3), so that it can be
autoloaded. Something like:

#include <asm/cpu_device_id.h>


static const struct x86_cpu_id avx_cpu_id[] = {
X86_FEATURE_MATCH(X86_FEATURE_AVX),
{}
};
MODULE_DEVICE_TABLE(x86cpu, avx_cpu_id);

Replace the manual check in init with

if (!x86_match_cpu(avx_cpu_id))
return -ENODEV;
Also drivers should never print anything when they cannot find hardware.
Remove that printk.

-Andi

--
ak@linux.intel.com -- Speaking for myself only


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