107 lines
3.1 KiB
C
107 lines
3.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* AES optimized using the CP Assist for Cryptographic Functions (CPACF)
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*
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* Copyright 2026 Google LLC
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*/
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#include <asm/cpacf.h>
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#include <linux/cpufeature.h>
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static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_cpacf_aes128);
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static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_cpacf_aes192);
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static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_cpacf_aes256);
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/*
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* When the CPU supports CPACF AES for the requested key length, we need only
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* save a copy of the raw AES key, as that's what the CPACF instructions need.
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*
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* When unsupported, fall back to the generic key expansion and en/decryption.
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*/
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static void aes_preparekey_arch(union aes_enckey_arch *k,
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union aes_invkey_arch *inv_k,
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const u8 *in_key, int key_len, int nrounds)
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{
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if (key_len == AES_KEYSIZE_128) {
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if (static_branch_likely(&have_cpacf_aes128)) {
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memcpy(k->raw_key, in_key, AES_KEYSIZE_128);
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return;
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}
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} else if (key_len == AES_KEYSIZE_192) {
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if (static_branch_likely(&have_cpacf_aes192)) {
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memcpy(k->raw_key, in_key, AES_KEYSIZE_192);
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return;
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}
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} else {
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if (static_branch_likely(&have_cpacf_aes256)) {
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memcpy(k->raw_key, in_key, AES_KEYSIZE_256);
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return;
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}
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}
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aes_expandkey_generic(k->rndkeys, inv_k ? inv_k->inv_rndkeys : NULL,
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in_key, key_len);
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}
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static inline bool aes_crypt_s390(const struct aes_enckey *key,
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u8 out[AES_BLOCK_SIZE],
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const u8 in[AES_BLOCK_SIZE], int decrypt)
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{
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if (key->len == AES_KEYSIZE_128) {
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if (static_branch_likely(&have_cpacf_aes128)) {
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cpacf_km(CPACF_KM_AES_128 | decrypt,
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(void *)key->k.raw_key, out, in,
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AES_BLOCK_SIZE);
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return true;
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}
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} else if (key->len == AES_KEYSIZE_192) {
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if (static_branch_likely(&have_cpacf_aes192)) {
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cpacf_km(CPACF_KM_AES_192 | decrypt,
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(void *)key->k.raw_key, out, in,
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AES_BLOCK_SIZE);
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return true;
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}
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} else {
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if (static_branch_likely(&have_cpacf_aes256)) {
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cpacf_km(CPACF_KM_AES_256 | decrypt,
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(void *)key->k.raw_key, out, in,
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AES_BLOCK_SIZE);
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return true;
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}
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}
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return false;
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}
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static void aes_encrypt_arch(const struct aes_enckey *key,
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u8 out[AES_BLOCK_SIZE],
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const u8 in[AES_BLOCK_SIZE])
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{
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if (likely(aes_crypt_s390(key, out, in, 0)))
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return;
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aes_encrypt_generic(key->k.rndkeys, key->nrounds, out, in);
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}
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static void aes_decrypt_arch(const struct aes_key *key,
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u8 out[AES_BLOCK_SIZE],
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const u8 in[AES_BLOCK_SIZE])
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{
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if (likely(aes_crypt_s390((const struct aes_enckey *)key, out, in,
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CPACF_DECRYPT)))
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return;
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aes_decrypt_generic(key->inv_k.inv_rndkeys, key->nrounds, out, in);
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}
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#define aes_mod_init_arch aes_mod_init_arch
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static void aes_mod_init_arch(void)
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{
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if (cpu_have_feature(S390_CPU_FEATURE_MSA)) {
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cpacf_mask_t km_functions;
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cpacf_query(CPACF_KM, &km_functions);
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if (cpacf_test_func(&km_functions, CPACF_KM_AES_128))
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static_branch_enable(&have_cpacf_aes128);
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if (cpacf_test_func(&km_functions, CPACF_KM_AES_192))
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static_branch_enable(&have_cpacf_aes192);
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if (cpacf_test_func(&km_functions, CPACF_KM_AES_256))
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static_branch_enable(&have_cpacf_aes256);
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}
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}
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