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0022 #include <crypto/algapi.h>
0023 #include <crypto/internal/chacha.h>
0024 #include <crypto/internal/simd.h>
0025 #include <crypto/internal/skcipher.h>
0026 #include <linux/jump_label.h>
0027 #include <linux/kernel.h>
0028 #include <linux/module.h>
0029
0030 #include <asm/hwcap.h>
0031 #include <asm/neon.h>
0032 #include <asm/simd.h>
0033
0034 asmlinkage void chacha_block_xor_neon(u32 *state, u8 *dst, const u8 *src,
0035 int nrounds);
0036 asmlinkage void chacha_4block_xor_neon(u32 *state, u8 *dst, const u8 *src,
0037 int nrounds, int bytes);
0038 asmlinkage void hchacha_block_neon(const u32 *state, u32 *out, int nrounds);
0039
0040 static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_neon);
0041
0042 static void chacha_doneon(u32 *state, u8 *dst, const u8 *src,
0043 int bytes, int nrounds)
0044 {
0045 while (bytes > 0) {
0046 int l = min(bytes, CHACHA_BLOCK_SIZE * 5);
0047
0048 if (l <= CHACHA_BLOCK_SIZE) {
0049 u8 buf[CHACHA_BLOCK_SIZE];
0050
0051 memcpy(buf, src, l);
0052 chacha_block_xor_neon(state, buf, buf, nrounds);
0053 memcpy(dst, buf, l);
0054 state[12] += 1;
0055 break;
0056 }
0057 chacha_4block_xor_neon(state, dst, src, nrounds, l);
0058 bytes -= l;
0059 src += l;
0060 dst += l;
0061 state[12] += DIV_ROUND_UP(l, CHACHA_BLOCK_SIZE);
0062 }
0063 }
0064
0065 void hchacha_block_arch(const u32 *state, u32 *stream, int nrounds)
0066 {
0067 if (!static_branch_likely(&have_neon) || !crypto_simd_usable()) {
0068 hchacha_block_generic(state, stream, nrounds);
0069 } else {
0070 kernel_neon_begin();
0071 hchacha_block_neon(state, stream, nrounds);
0072 kernel_neon_end();
0073 }
0074 }
0075 EXPORT_SYMBOL(hchacha_block_arch);
0076
0077 void chacha_init_arch(u32 *state, const u32 *key, const u8 *iv)
0078 {
0079 chacha_init_generic(state, key, iv);
0080 }
0081 EXPORT_SYMBOL(chacha_init_arch);
0082
0083 void chacha_crypt_arch(u32 *state, u8 *dst, const u8 *src, unsigned int bytes,
0084 int nrounds)
0085 {
0086 if (!static_branch_likely(&have_neon) || bytes <= CHACHA_BLOCK_SIZE ||
0087 !crypto_simd_usable())
0088 return chacha_crypt_generic(state, dst, src, bytes, nrounds);
0089
0090 do {
0091 unsigned int todo = min_t(unsigned int, bytes, SZ_4K);
0092
0093 kernel_neon_begin();
0094 chacha_doneon(state, dst, src, todo, nrounds);
0095 kernel_neon_end();
0096
0097 bytes -= todo;
0098 src += todo;
0099 dst += todo;
0100 } while (bytes);
0101 }
0102 EXPORT_SYMBOL(chacha_crypt_arch);
0103
0104 static int chacha_neon_stream_xor(struct skcipher_request *req,
0105 const struct chacha_ctx *ctx, const u8 *iv)
0106 {
0107 struct skcipher_walk walk;
0108 u32 state[16];
0109 int err;
0110
0111 err = skcipher_walk_virt(&walk, req, false);
0112
0113 chacha_init_generic(state, ctx->key, iv);
0114
0115 while (walk.nbytes > 0) {
0116 unsigned int nbytes = walk.nbytes;
0117
0118 if (nbytes < walk.total)
0119 nbytes = rounddown(nbytes, walk.stride);
0120
0121 if (!static_branch_likely(&have_neon) ||
0122 !crypto_simd_usable()) {
0123 chacha_crypt_generic(state, walk.dst.virt.addr,
0124 walk.src.virt.addr, nbytes,
0125 ctx->nrounds);
0126 } else {
0127 kernel_neon_begin();
0128 chacha_doneon(state, walk.dst.virt.addr,
0129 walk.src.virt.addr, nbytes, ctx->nrounds);
0130 kernel_neon_end();
0131 }
0132 err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
0133 }
0134
0135 return err;
0136 }
0137
0138 static int chacha_neon(struct skcipher_request *req)
0139 {
0140 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
0141 struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
0142
0143 return chacha_neon_stream_xor(req, ctx, req->iv);
0144 }
0145
0146 static int xchacha_neon(struct skcipher_request *req)
0147 {
0148 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
0149 struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
0150 struct chacha_ctx subctx;
0151 u32 state[16];
0152 u8 real_iv[16];
0153
0154 chacha_init_generic(state, ctx->key, req->iv);
0155 hchacha_block_arch(state, subctx.key, ctx->nrounds);
0156 subctx.nrounds = ctx->nrounds;
0157
0158 memcpy(&real_iv[0], req->iv + 24, 8);
0159 memcpy(&real_iv[8], req->iv + 16, 8);
0160 return chacha_neon_stream_xor(req, &subctx, real_iv);
0161 }
0162
0163 static struct skcipher_alg algs[] = {
0164 {
0165 .base.cra_name = "chacha20",
0166 .base.cra_driver_name = "chacha20-neon",
0167 .base.cra_priority = 300,
0168 .base.cra_blocksize = 1,
0169 .base.cra_ctxsize = sizeof(struct chacha_ctx),
0170 .base.cra_module = THIS_MODULE,
0171
0172 .min_keysize = CHACHA_KEY_SIZE,
0173 .max_keysize = CHACHA_KEY_SIZE,
0174 .ivsize = CHACHA_IV_SIZE,
0175 .chunksize = CHACHA_BLOCK_SIZE,
0176 .walksize = 5 * CHACHA_BLOCK_SIZE,
0177 .setkey = chacha20_setkey,
0178 .encrypt = chacha_neon,
0179 .decrypt = chacha_neon,
0180 }, {
0181 .base.cra_name = "xchacha20",
0182 .base.cra_driver_name = "xchacha20-neon",
0183 .base.cra_priority = 300,
0184 .base.cra_blocksize = 1,
0185 .base.cra_ctxsize = sizeof(struct chacha_ctx),
0186 .base.cra_module = THIS_MODULE,
0187
0188 .min_keysize = CHACHA_KEY_SIZE,
0189 .max_keysize = CHACHA_KEY_SIZE,
0190 .ivsize = XCHACHA_IV_SIZE,
0191 .chunksize = CHACHA_BLOCK_SIZE,
0192 .walksize = 5 * CHACHA_BLOCK_SIZE,
0193 .setkey = chacha20_setkey,
0194 .encrypt = xchacha_neon,
0195 .decrypt = xchacha_neon,
0196 }, {
0197 .base.cra_name = "xchacha12",
0198 .base.cra_driver_name = "xchacha12-neon",
0199 .base.cra_priority = 300,
0200 .base.cra_blocksize = 1,
0201 .base.cra_ctxsize = sizeof(struct chacha_ctx),
0202 .base.cra_module = THIS_MODULE,
0203
0204 .min_keysize = CHACHA_KEY_SIZE,
0205 .max_keysize = CHACHA_KEY_SIZE,
0206 .ivsize = XCHACHA_IV_SIZE,
0207 .chunksize = CHACHA_BLOCK_SIZE,
0208 .walksize = 5 * CHACHA_BLOCK_SIZE,
0209 .setkey = chacha12_setkey,
0210 .encrypt = xchacha_neon,
0211 .decrypt = xchacha_neon,
0212 }
0213 };
0214
0215 static int __init chacha_simd_mod_init(void)
0216 {
0217 if (!cpu_have_named_feature(ASIMD))
0218 return 0;
0219
0220 static_branch_enable(&have_neon);
0221
0222 return IS_REACHABLE(CONFIG_CRYPTO_SKCIPHER) ?
0223 crypto_register_skciphers(algs, ARRAY_SIZE(algs)) : 0;
0224 }
0225
0226 static void __exit chacha_simd_mod_fini(void)
0227 {
0228 if (IS_REACHABLE(CONFIG_CRYPTO_SKCIPHER) && cpu_have_named_feature(ASIMD))
0229 crypto_unregister_skciphers(algs, ARRAY_SIZE(algs));
0230 }
0231
0232 module_init(chacha_simd_mod_init);
0233 module_exit(chacha_simd_mod_fini);
0234
0235 MODULE_DESCRIPTION("ChaCha and XChaCha stream ciphers (NEON accelerated)");
0236 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
0237 MODULE_LICENSE("GPL v2");
0238 MODULE_ALIAS_CRYPTO("chacha20");
0239 MODULE_ALIAS_CRYPTO("chacha20-neon");
0240 MODULE_ALIAS_CRYPTO("xchacha20");
0241 MODULE_ALIAS_CRYPTO("xchacha20-neon");
0242 MODULE_ALIAS_CRYPTO("xchacha12");
0243 MODULE_ALIAS_CRYPTO("xchacha12-neon");
