crypto/vmx/ghash.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * GHASH routines supporting VMX instructions on the Power 8
0004  *
0005  * Copyright (C) 2015, 2019 International Business Machines Inc.
0006  *
0007  * Author: Marcelo Henrique Cerri <mhcerri@br.ibm.com>
0008  *
0009  * Extended by Daniel Axtens <dja@axtens.net> to replace the fallback
0010  * mechanism. The new approach is based on arm64 code, which is:
0011  *   Copyright (C) 2014 - 2018 Linaro Ltd. <ard.biesheuvel@linaro.org>
0012  */
0013
0014 #include <linux/types.h>
0015 #include <linux/err.h>
0016 #include <linux/crypto.h>
0017 #include <linux/delay.h>
0018 #include <asm/simd.h>
0019 #include <asm/switch_to.h>
0020 #include <crypto/aes.h>
0021 #include <crypto/ghash.h>
0022 #include <crypto/scatterwalk.h>
0023 #include <crypto/internal/hash.h>
0024 #include <crypto/internal/simd.h>
0025 #include <crypto/b128ops.h>
0026 #include "aesp8-ppc.h"
0027
0028 void gcm_init_p8(u128 htable[16], const u64 Xi[2]);
0029 void gcm_gmult_p8(u64 Xi[2], const u128 htable[16]);
0030 void gcm_ghash_p8(u64 Xi[2], const u128 htable[16],
0031           const u8 *in, size_t len);
0032
0033 struct p8_ghash_ctx {
0034     /* key used by vector asm */
0035     u128 htable[16];
0036     /* key used by software fallback */
0037     be128 key;
0038 };
0039
0040 struct p8_ghash_desc_ctx {
0041     u64 shash[2];
0042     u8 buffer[GHASH_DIGEST_SIZE];
0043     int bytes;
0044 };
0045
0046 static int p8_ghash_init(struct shash_desc *desc)
0047 {
0048     struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
0049
0050     dctx->bytes = 0;
0051     memset(dctx->shash, 0, GHASH_DIGEST_SIZE);
0052     return 0;
0053 }
0054
0055 static int p8_ghash_setkey(struct crypto_shash *tfm, const u8 *key,
0056                unsigned int keylen)
0057 {
0058     struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(tfm));
0059
0060     if (keylen != GHASH_BLOCK_SIZE)
0061         return -EINVAL;
0062
0063     preempt_disable();
0064     pagefault_disable();
0065     enable_kernel_vsx();
0066     gcm_init_p8(ctx->htable, (const u64 *) key);
0067     disable_kernel_vsx();
0068     pagefault_enable();
0069     preempt_enable();
0070
0071     memcpy(&ctx->key, key, GHASH_BLOCK_SIZE);
0072
0073     return 0;
0074 }
0075
0076 static inline void __ghash_block(struct p8_ghash_ctx *ctx,
0077                  struct p8_ghash_desc_ctx *dctx)
0078 {
0079     if (crypto_simd_usable()) {
0080         preempt_disable();
0081         pagefault_disable();
0082         enable_kernel_vsx();
0083         gcm_ghash_p8(dctx->shash, ctx->htable,
0084                 dctx->buffer, GHASH_DIGEST_SIZE);
0085         disable_kernel_vsx();
0086         pagefault_enable();
0087         preempt_enable();
0088     } else {
0089         crypto_xor((u8 *)dctx->shash, dctx->buffer, GHASH_BLOCK_SIZE);
0090         gf128mul_lle((be128 *)dctx->shash, &ctx->key);
0091     }
0092 }
0093
0094 static inline void __ghash_blocks(struct p8_ghash_ctx *ctx,
0095                   struct p8_ghash_desc_ctx *dctx,
0096                   const u8 *src, unsigned int srclen)
0097 {
0098     if (crypto_simd_usable()) {
0099         preempt_disable();
0100         pagefault_disable();
0101         enable_kernel_vsx();
0102         gcm_ghash_p8(dctx->shash, ctx->htable,
0103                 src, srclen);
0104         disable_kernel_vsx();
0105         pagefault_enable();
0106         preempt_enable();
0107     } else {
0108         while (srclen >= GHASH_BLOCK_SIZE) {
0109             crypto_xor((u8 *)dctx->shash, src, GHASH_BLOCK_SIZE);
0110             gf128mul_lle((be128 *)dctx->shash, &ctx->key);
0111             srclen -= GHASH_BLOCK_SIZE;
0112             src += GHASH_BLOCK_SIZE;
0113         }
0114     }
0115 }
0116
0117 static int p8_ghash_update(struct shash_desc *desc,
0118                const u8 *src, unsigned int srclen)
0119 {
0120     unsigned int len;
0121     struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));
0122     struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
0123
0124     if (dctx->bytes) {
0125         if (dctx->bytes + srclen < GHASH_DIGEST_SIZE) {
0126             memcpy(dctx->buffer + dctx->bytes, src,
0127                 srclen);
0128             dctx->bytes += srclen;
0129             return 0;
0130         }
0131         memcpy(dctx->buffer + dctx->bytes, src,
0132             GHASH_DIGEST_SIZE - dctx->bytes);
0133
0134         __ghash_block(ctx, dctx);
0135
0136         src += GHASH_DIGEST_SIZE - dctx->bytes;
0137         srclen -= GHASH_DIGEST_SIZE - dctx->bytes;
0138         dctx->bytes = 0;
0139     }
0140     len = srclen & ~(GHASH_DIGEST_SIZE - 1);
0141     if (len) {
0142         __ghash_blocks(ctx, dctx, src, len);
0143         src += len;
0144         srclen -= len;
0145     }
0146     if (srclen) {
0147         memcpy(dctx->buffer, src, srclen);
0148         dctx->bytes = srclen;
0149     }
0150     return 0;
0151 }
0152
0153 static int p8_ghash_final(struct shash_desc *desc, u8 *out)
0154 {
0155     int i;
0156     struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));
0157     struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
0158
0159     if (dctx->bytes) {
0160         for (i = dctx->bytes; i < GHASH_DIGEST_SIZE; i++)
0161             dctx->buffer[i] = 0;
0162         __ghash_block(ctx, dctx);
0163         dctx->bytes = 0;
0164     }
0165     memcpy(out, dctx->shash, GHASH_DIGEST_SIZE);
0166     return 0;
0167 }
0168
0169 struct shash_alg p8_ghash_alg = {
0170     .digestsize = GHASH_DIGEST_SIZE,
0171     .init = p8_ghash_init,
0172     .update = p8_ghash_update,
0173     .final = p8_ghash_final,
0174     .setkey = p8_ghash_setkey,
0175     .descsize = sizeof(struct p8_ghash_desc_ctx)
0176         + sizeof(struct ghash_desc_ctx),
0177     .base = {
0178          .cra_name = "ghash",
0179          .cra_driver_name = "p8_ghash",
0180          .cra_priority = 1000,
0181          .cra_blocksize = GHASH_BLOCK_SIZE,
0182          .cra_ctxsize = sizeof(struct p8_ghash_ctx),
0183          .cra_module = THIS_MODULE,
0184     },
0185 };