1 // SPDX-License-Identifier: GPL-2.0-only 2 /** 3 * AES CTR routines supporting VMX instructions on the Power 8 4 * 5 * Copyright (C) 2015 International Business Machines Inc. 6 * 7 * Author: Marcelo Henrique Cerri <mhcerri@br.ibm.com> 8 */ 9 10 #include <linux/types.h> 11 #include <linux/err.h> 12 #include <linux/crypto.h> 13 #include <linux/delay.h> 14 #include <asm/simd.h> 15 #include <asm/switch_to.h> 16 #include <crypto/aes.h> 17 #include <crypto/internal/simd.h> 18 #include <crypto/scatterwalk.h> 19 #include <crypto/skcipher.h> 20 21 #include "aesp8-ppc.h" 22 23 struct p8_aes_ctr_ctx { 24 struct crypto_sync_skcipher *fallback; 25 struct aes_key enc_key; 26 }; 27 28 static int p8_aes_ctr_init(struct crypto_tfm *tfm) 29 { 30 const char *alg = crypto_tfm_alg_name(tfm); 31 struct crypto_sync_skcipher *fallback; 32 struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm); 33 34 fallback = crypto_alloc_sync_skcipher(alg, 0, 35 CRYPTO_ALG_NEED_FALLBACK); 36 if (IS_ERR(fallback)) { 37 printk(KERN_ERR 38 "Failed to allocate transformation for '%s': %ld\n", 39 alg, PTR_ERR(fallback)); 40 return PTR_ERR(fallback); 41 } 42 43 crypto_sync_skcipher_set_flags( 44 fallback, 45 crypto_skcipher_get_flags((struct crypto_skcipher *)tfm)); 46 ctx->fallback = fallback; 47 48 return 0; 49 } 50 51 static void p8_aes_ctr_exit(struct crypto_tfm *tfm) 52 { 53 struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm); 54 55 if (ctx->fallback) { 56 crypto_free_sync_skcipher(ctx->fallback); 57 ctx->fallback = NULL; 58 } 59 } 60 61 static int p8_aes_ctr_setkey(struct crypto_tfm *tfm, const u8 *key, 62 unsigned int keylen) 63 { 64 int ret; 65 struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm); 66 67 preempt_disable(); 68 pagefault_disable(); 69 enable_kernel_vsx(); 70 ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key); 71 disable_kernel_vsx(); 72 pagefault_enable(); 73 preempt_enable(); 74 75 ret |= crypto_sync_skcipher_setkey(ctx->fallback, key, keylen); 76 77 return ret ? -EINVAL : 0; 78 } 79 80 static void p8_aes_ctr_final(struct p8_aes_ctr_ctx *ctx, 81 struct blkcipher_walk *walk) 82 { 83 u8 *ctrblk = walk->iv; 84 u8 keystream[AES_BLOCK_SIZE]; 85 u8 *src = walk->src.virt.addr; 86 u8 *dst = walk->dst.virt.addr; 87 unsigned int nbytes = walk->nbytes; 88 89 preempt_disable(); 90 pagefault_disable(); 91 enable_kernel_vsx(); 92 aes_p8_encrypt(ctrblk, keystream, &ctx->enc_key); 93 disable_kernel_vsx(); 94 pagefault_enable(); 95 preempt_enable(); 96 97 crypto_xor_cpy(dst, keystream, src, nbytes); 98 crypto_inc(ctrblk, AES_BLOCK_SIZE); 99 } 100 101 static int p8_aes_ctr_crypt(struct blkcipher_desc *desc, 102 struct scatterlist *dst, 103 struct scatterlist *src, unsigned int nbytes) 104 { 105 int ret; 106 u64 inc; 107 struct blkcipher_walk walk; 108 struct p8_aes_ctr_ctx *ctx = 109 crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm)); 110 111 if (!crypto_simd_usable()) { 112 SYNC_SKCIPHER_REQUEST_ON_STACK(req, ctx->fallback); 113 skcipher_request_set_sync_tfm(req, ctx->fallback); 114 skcipher_request_set_callback(req, desc->flags, NULL, NULL); 115 skcipher_request_set_crypt(req, src, dst, nbytes, desc->info); 116 ret = crypto_skcipher_encrypt(req); 117 skcipher_request_zero(req); 118 } else { 119 blkcipher_walk_init(&walk, dst, src, nbytes); 120 ret = blkcipher_walk_virt_block(desc, &walk, AES_BLOCK_SIZE); 121 while ((nbytes = walk.nbytes) >= AES_BLOCK_SIZE) { 122 preempt_disable(); 123 pagefault_disable(); 124 enable_kernel_vsx(); 125 aes_p8_ctr32_encrypt_blocks(walk.src.virt.addr, 126 walk.dst.virt.addr, 127 (nbytes & 128 AES_BLOCK_MASK) / 129 AES_BLOCK_SIZE, 130 &ctx->enc_key, 131 walk.iv); 132 disable_kernel_vsx(); 133 pagefault_enable(); 134 preempt_enable(); 135 136 /* We need to update IV mostly for last bytes/round */ 137 inc = (nbytes & AES_BLOCK_MASK) / AES_BLOCK_SIZE; 138 if (inc > 0) 139 while (inc--) 140 crypto_inc(walk.iv, AES_BLOCK_SIZE); 141 142 nbytes &= AES_BLOCK_SIZE - 1; 143 ret = blkcipher_walk_done(desc, &walk, nbytes); 144 } 145 if (walk.nbytes) { 146 p8_aes_ctr_final(ctx, &walk); 147 ret = blkcipher_walk_done(desc, &walk, 0); 148 } 149 } 150 151 return ret; 152 } 153 154 struct crypto_alg p8_aes_ctr_alg = { 155 .cra_name = "ctr(aes)", 156 .cra_driver_name = "p8_aes_ctr", 157 .cra_module = THIS_MODULE, 158 .cra_priority = 2000, 159 .cra_type = &crypto_blkcipher_type, 160 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK, 161 .cra_alignmask = 0, 162 .cra_blocksize = 1, 163 .cra_ctxsize = sizeof(struct p8_aes_ctr_ctx), 164 .cra_init = p8_aes_ctr_init, 165 .cra_exit = p8_aes_ctr_exit, 166 .cra_blkcipher = { 167 .ivsize = AES_BLOCK_SIZE, 168 .min_keysize = AES_MIN_KEY_SIZE, 169 .max_keysize = AES_MAX_KEY_SIZE, 170 .setkey = p8_aes_ctr_setkey, 171 .encrypt = p8_aes_ctr_crypt, 172 .decrypt = p8_aes_ctr_crypt, 173 }, 174 }; 175