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-rw-r--r--arch/s390/crypto/chacha-glue.c130
1 files changed, 130 insertions, 0 deletions
diff --git a/arch/s390/crypto/chacha-glue.c b/arch/s390/crypto/chacha-glue.c
new file mode 100644
index 0000000000..5fae187f94
--- /dev/null
+++ b/arch/s390/crypto/chacha-glue.c
@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * s390 ChaCha stream cipher.
+ *
+ * Copyright IBM Corp. 2021
+ */
+
+#define KMSG_COMPONENT "chacha_s390"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <crypto/internal/chacha.h>
+#include <crypto/internal/skcipher.h>
+#include <crypto/algapi.h>
+#include <linux/cpufeature.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sizes.h>
+#include <asm/fpu/api.h>
+#include "chacha-s390.h"
+
+static void chacha20_crypt_s390(u32 *state, u8 *dst, const u8 *src,
+ unsigned int nbytes, const u32 *key,
+ u32 *counter)
+{
+ struct kernel_fpu vxstate;
+
+ kernel_fpu_begin(&vxstate, KERNEL_VXR);
+ chacha20_vx(dst, src, nbytes, key, counter);
+ kernel_fpu_end(&vxstate, KERNEL_VXR);
+
+ *counter += round_up(nbytes, CHACHA_BLOCK_SIZE) / CHACHA_BLOCK_SIZE;
+}
+
+static int chacha20_s390(struct skcipher_request *req)
+{
+ struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
+ u32 state[CHACHA_STATE_WORDS] __aligned(16);
+ struct skcipher_walk walk;
+ unsigned int nbytes;
+ int rc;
+
+ rc = skcipher_walk_virt(&walk, req, false);
+ chacha_init_generic(state, ctx->key, req->iv);
+
+ while (walk.nbytes > 0) {
+ nbytes = walk.nbytes;
+ if (nbytes < walk.total)
+ nbytes = round_down(nbytes, walk.stride);
+
+ if (nbytes <= CHACHA_BLOCK_SIZE) {
+ chacha_crypt_generic(state, walk.dst.virt.addr,
+ walk.src.virt.addr, nbytes,
+ ctx->nrounds);
+ } else {
+ chacha20_crypt_s390(state, walk.dst.virt.addr,
+ walk.src.virt.addr, nbytes,
+ &state[4], &state[12]);
+ }
+ rc = skcipher_walk_done(&walk, walk.nbytes - nbytes);
+ }
+ return rc;
+}
+
+void hchacha_block_arch(const u32 *state, u32 *stream, int nrounds)
+{
+ /* TODO: implement hchacha_block_arch() in assembly */
+ hchacha_block_generic(state, stream, nrounds);
+}
+EXPORT_SYMBOL(hchacha_block_arch);
+
+void chacha_init_arch(u32 *state, const u32 *key, const u8 *iv)
+{
+ chacha_init_generic(state, key, iv);
+}
+EXPORT_SYMBOL(chacha_init_arch);
+
+void chacha_crypt_arch(u32 *state, u8 *dst, const u8 *src,
+ unsigned int bytes, int nrounds)
+{
+ /* s390 chacha20 implementation has 20 rounds hard-coded,
+ * it cannot handle a block of data or less, but otherwise
+ * it can handle data of arbitrary size
+ */
+ if (bytes <= CHACHA_BLOCK_SIZE || nrounds != 20 || !MACHINE_HAS_VX)
+ chacha_crypt_generic(state, dst, src, bytes, nrounds);
+ else
+ chacha20_crypt_s390(state, dst, src, bytes,
+ &state[4], &state[12]);
+}
+EXPORT_SYMBOL(chacha_crypt_arch);
+
+static struct skcipher_alg chacha_algs[] = {
+ {
+ .base.cra_name = "chacha20",
+ .base.cra_driver_name = "chacha20-s390",
+ .base.cra_priority = 900,
+ .base.cra_blocksize = 1,
+ .base.cra_ctxsize = sizeof(struct chacha_ctx),
+ .base.cra_module = THIS_MODULE,
+
+ .min_keysize = CHACHA_KEY_SIZE,
+ .max_keysize = CHACHA_KEY_SIZE,
+ .ivsize = CHACHA_IV_SIZE,
+ .chunksize = CHACHA_BLOCK_SIZE,
+ .setkey = chacha20_setkey,
+ .encrypt = chacha20_s390,
+ .decrypt = chacha20_s390,
+ }
+};
+
+static int __init chacha_mod_init(void)
+{
+ return IS_REACHABLE(CONFIG_CRYPTO_SKCIPHER) ?
+ crypto_register_skciphers(chacha_algs, ARRAY_SIZE(chacha_algs)) : 0;
+}
+
+static void __exit chacha_mod_fini(void)
+{
+ if (IS_REACHABLE(CONFIG_CRYPTO_SKCIPHER))
+ crypto_unregister_skciphers(chacha_algs, ARRAY_SIZE(chacha_algs));
+}
+
+module_cpu_feature_match(S390_CPU_FEATURE_VXRS, chacha_mod_init);
+module_exit(chacha_mod_fini);
+
+MODULE_DESCRIPTION("ChaCha20 stream cipher");
+MODULE_LICENSE("GPL v2");
+
+MODULE_ALIAS_CRYPTO("chacha20");