--- /dev/null
+/*
+ * aes-ce-cipher.c - core AES cipher using ARMv8 Crypto Extensions
+ *
+ * Copyright (C) 2013 - 2014 Linaro Ltd <ard.biesheuvel@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <asm/neon.h>
+#include <crypto/aes.h>
+#include <linux/cpufeature.h>
+#include <linux/crypto.h>
+#include <linux/module.h>
+
+#include "aes-ce-setkey.h"
+
+MODULE_DESCRIPTION("Synchronous AES cipher using ARMv8 Crypto Extensions");
+MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
+MODULE_LICENSE("GPL v2");
+
+struct aes_block {
+ u8 b[AES_BLOCK_SIZE];
+};
+
+static int num_rounds(struct crypto_aes_ctx *ctx)
+{
+ /*
+ * # of rounds specified by AES:
+ * 128 bit key 10 rounds
+ * 192 bit key 12 rounds
+ * 256 bit key 14 rounds
+ * => n byte key => 6 + (n/4) rounds
+ */
+ return 6 + ctx->key_length / 4;
+}
+
+static void aes_cipher_encrypt(struct crypto_tfm *tfm, u8 dst[], u8 const src[])
+{
+ struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
+ struct aes_block *out = (struct aes_block *)dst;
+ struct aes_block const *in = (struct aes_block *)src;
+ void *dummy0;
+ int dummy1;
+
+ kernel_neon_begin_partial(4);
+
+ __asm__(" ld1 {v0.16b}, %[in] ;"
+ " ld1 {v1.2d}, [%[key]], #16 ;"
+ " cmp %w[rounds], #10 ;"
+ " bmi 0f ;"
+ " bne 3f ;"
+ " mov v3.16b, v1.16b ;"
+ " b 2f ;"
+ "0: mov v2.16b, v1.16b ;"
+ " ld1 {v3.2d}, [%[key]], #16 ;"
+ "1: aese v0.16b, v2.16b ;"
+ " aesmc v0.16b, v0.16b ;"
+ "2: ld1 {v1.2d}, [%[key]], #16 ;"
+ " aese v0.16b, v3.16b ;"
+ " aesmc v0.16b, v0.16b ;"
+ "3: ld1 {v2.2d}, [%[key]], #16 ;"
+ " subs %w[rounds], %w[rounds], #3 ;"
+ " aese v0.16b, v1.16b ;"
+ " aesmc v0.16b, v0.16b ;"
+ " ld1 {v3.2d}, [%[key]], #16 ;"
+ " bpl 1b ;"
+ " aese v0.16b, v2.16b ;"
+ " eor v0.16b, v0.16b, v3.16b ;"
+ " st1 {v0.16b}, %[out] ;"
+
+ : [out] "=Q"(*out),
+ [key] "=r"(dummy0),
+ [rounds] "=r"(dummy1)
+ : [in] "Q"(*in),
+ "1"(ctx->key_enc),
+ "2"(num_rounds(ctx) - 2)
+ : "cc");
+
+ kernel_neon_end();
+}
+
+static void aes_cipher_decrypt(struct crypto_tfm *tfm, u8 dst[], u8 const src[])
+{
+ struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
+ struct aes_block *out = (struct aes_block *)dst;
+ struct aes_block const *in = (struct aes_block *)src;
+ void *dummy0;
+ int dummy1;
+
+ kernel_neon_begin_partial(4);
+
+ __asm__(" ld1 {v0.16b}, %[in] ;"
+ " ld1 {v1.2d}, [%[key]], #16 ;"
+ " cmp %w[rounds], #10 ;"
+ " bmi 0f ;"
+ " bne 3f ;"
+ " mov v3.16b, v1.16b ;"
+ " b 2f ;"
+ "0: mov v2.16b, v1.16b ;"
+ " ld1 {v3.2d}, [%[key]], #16 ;"
+ "1: aesd v0.16b, v2.16b ;"
+ " aesimc v0.16b, v0.16b ;"
+ "2: ld1 {v1.2d}, [%[key]], #16 ;"
+ " aesd v0.16b, v3.16b ;"
+ " aesimc v0.16b, v0.16b ;"
+ "3: ld1 {v2.2d}, [%[key]], #16 ;"
+ " subs %w[rounds], %w[rounds], #3 ;"
+ " aesd v0.16b, v1.16b ;"
+ " aesimc v0.16b, v0.16b ;"
+ " ld1 {v3.2d}, [%[key]], #16 ;"
+ " bpl 1b ;"
+ " aesd v0.16b, v2.16b ;"
+ " eor v0.16b, v0.16b, v3.16b ;"
+ " st1 {v0.16b}, %[out] ;"
+
+ : [out] "=Q"(*out),
+ [key] "=r"(dummy0),
+ [rounds] "=r"(dummy1)
+ : [in] "Q"(*in),
+ "1"(ctx->key_dec),
+ "2"(num_rounds(ctx) - 2)
+ : "cc");
+
+ kernel_neon_end();
+}
+
+/*
+ * aes_sub() - use the aese instruction to perform the AES sbox substitution
+ * on each byte in 'input'
+ */
+static u32 aes_sub(u32 input)
+{
+ u32 ret;
+
+ __asm__("dup v1.4s, %w[in] ;"
+ "movi v0.16b, #0 ;"
+ "aese v0.16b, v1.16b ;"
+ "umov %w[out], v0.4s[0] ;"
+
+ : [out] "=r"(ret)
+ : [in] "r"(input)
+ : "v0","v1");
+
+ return ret;
+}
+
+int ce_aes_expandkey(struct crypto_aes_ctx *ctx, const u8 *in_key,
+ unsigned int key_len)
+{
+ /*
+ * The AES key schedule round constants
+ */
+ static u8 const rcon[] = {
+ 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36,
+ };
+
+ u32 kwords = key_len / sizeof(u32);
+ struct aes_block *key_enc, *key_dec;
+ int i, j;
+
+ if (key_len != AES_KEYSIZE_128 &&
+ key_len != AES_KEYSIZE_192 &&
+ key_len != AES_KEYSIZE_256)
+ return -EINVAL;
+
+ memcpy(ctx->key_enc, in_key, key_len);
+ ctx->key_length = key_len;
+
+ kernel_neon_begin_partial(2);
+ for (i = 0; i < sizeof(rcon); i++) {
+ u32 *rki = ctx->key_enc + (i * kwords);
+ u32 *rko = rki + kwords;
+
+ rko[0] = ror32(aes_sub(rki[kwords - 1]), 8) ^ rcon[i] ^ rki[0];
+ rko[1] = rko[0] ^ rki[1];
+ rko[2] = rko[1] ^ rki[2];
+ rko[3] = rko[2] ^ rki[3];
+
+ if (key_len == AES_KEYSIZE_192) {
+ if (i >= 7)
+ break;
+ rko[4] = rko[3] ^ rki[4];
+ rko[5] = rko[4] ^ rki[5];
+ } else if (key_len == AES_KEYSIZE_256) {
+ if (i >= 6)
+ break;
+ rko[4] = aes_sub(rko[3]) ^ rki[4];
+ rko[5] = rko[4] ^ rki[5];
+ rko[6] = rko[5] ^ rki[6];
+ rko[7] = rko[6] ^ rki[7];
+ }
+ }
+
+ /*
+ * Generate the decryption keys for the Equivalent Inverse Cipher.
+ * This involves reversing the order of the round keys, and applying
+ * the Inverse Mix Columns transformation on all but the first and
+ * the last one.
+ */
+ key_enc = (struct aes_block *)ctx->key_enc;
+ key_dec = (struct aes_block *)ctx->key_dec;
+ j = num_rounds(ctx);
+
+ key_dec[0] = key_enc[j];
+ for (i = 1, j--; j > 0; i++, j--)
+ __asm__("ld1 {v0.16b}, %[in] ;"
+ "aesimc v1.16b, v0.16b ;"
+ "st1 {v1.16b}, %[out] ;"
+
+ : [out] "=Q"(key_dec[i])
+ : [in] "Q"(key_enc[j])
+ : "v0","v1");
+ key_dec[i] = key_enc[0];
+
+ kernel_neon_end();
+ return 0;
+}
+EXPORT_SYMBOL(ce_aes_expandkey);
+
+int ce_aes_setkey(struct crypto_tfm *tfm, const u8 *in_key,
+ unsigned int key_len)
+{
+ struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
+ int ret;
+
+ ret = ce_aes_expandkey(ctx, in_key, key_len);
+ if (!ret)
+ return 0;
+
+ tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
+ return -EINVAL;
+}
+EXPORT_SYMBOL(ce_aes_setkey);
+
+static struct crypto_alg aes_alg = {
+ .cra_name = "aes",
+ .cra_driver_name = "aes-ce",
+ .cra_priority = 300,
+ .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
+ .cra_blocksize = AES_BLOCK_SIZE,
+ .cra_ctxsize = sizeof(struct crypto_aes_ctx),
+ .cra_module = THIS_MODULE,
+ .cra_cipher = {
+ .cia_min_keysize = AES_MIN_KEY_SIZE,
+ .cia_max_keysize = AES_MAX_KEY_SIZE,
+ .cia_setkey = ce_aes_setkey,
+ .cia_encrypt = aes_cipher_encrypt,
+ .cia_decrypt = aes_cipher_decrypt
+ }
+};
+
+static int __init aes_mod_init(void)
+{
+ return crypto_register_alg(&aes_alg);
+}
+
+static void __exit aes_mod_exit(void)
+{
+ crypto_unregister_alg(&aes_alg);
+}
+
+module_cpu_feature_match(AES, aes_mod_init);
+module_exit(aes_mod_exit);
Code Review / kvmfornfv.git / blobdiff