+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Glue code for accelerated AES-GCM stitched implementation for ppc64le.
+ *
+ * Copyright 2022- IBM Inc. All rights reserved
+ */
+
+#include <asm/unaligned.h>
+#include <asm/simd.h>
+#include <asm/switch_to.h>
+#include <crypto/algapi.h>
+#include <crypto/aes.h>
+#include <crypto/algapi.h>
+#include <crypto/b128ops.h>
+#include <crypto/gf128mul.h>
+#include <crypto/internal/simd.h>
+#include <crypto/internal/aead.h>
+#include <crypto/internal/hash.h>
+#include <crypto/internal/skcipher.h>
+#include <crypto/scatterwalk.h>
+#include <linux/cpufeature.h>
+#include <linux/crypto.h>
+#include <linux/module.h>
+#include <linux/types.h>
+
+#define PPC_MODULE_FEATURE_P10 (32 + ilog2(PPC_FEATURE2_ARCH_3_1))
+#define PPC_ALIGN 16
+#define GCM_IV_SIZE 12
+
+MODULE_DESCRIPTION("PPC64le AES-GCM with Stitched implementation");
+MODULE_AUTHOR("Danny Tsen <dtsen@linux.ibm.com");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS_CRYPTO("aes");
+
+asmlinkage int aes_p8_set_encrypt_key(const u8 *userKey, const int bits,
+ void *key);
+asmlinkage void aes_p8_encrypt(const u8 *in, u8 *out, const void *key);
+asmlinkage void aes_p10_gcm_encrypt(u8 *in, u8 *out, size_t len,
+ void *rkey, u8 *iv, void *Xi);
+asmlinkage void aes_p10_gcm_decrypt(u8 *in, u8 *out, size_t len,
+ void *rkey, u8 *iv, void *Xi);
+asmlinkage void gcm_init_htable(unsigned char htable[256], unsigned char Xi[16]);
+asmlinkage void gcm_ghash_p8(unsigned char *Xi, unsigned char *Htable,
+ unsigned char *aad, unsigned int alen);
+
+struct aes_key {
+ u8 key[AES_MAX_KEYLENGTH];
+ u64 rounds;
+};
+
+struct gcm_ctx {
+ u8 iv[16];
+ u8 ivtag[16];
+ u8 aad_hash[16];
+ u64 aadLen;
+ u64 Plen; /* offset 56 - used in aes_p10_gcm_{en/de}crypt */
+};
+struct Hash_ctx {
+ u8 H[16]; /* subkey */
+ u8 Htable[256]; /* Xi, Hash table(offset 32) */
+};
+
+struct p10_aes_gcm_ctx {
+ struct aes_key enc_key;
+};
+
+static void vsx_begin(void)
+{
+ preempt_disable();
+ enable_kernel_vsx();
+}
+
+static void vsx_end(void)
+{
+ disable_kernel_vsx();
+ preempt_enable();
+}
+
+static void set_subkey(unsigned char *hash)
+{
+ *(u64 *)&hash[0] = be64_to_cpup((__be64 *)&hash[0]);
+ *(u64 *)&hash[8] = be64_to_cpup((__be64 *)&hash[8]);
+}
+
+/*
+ * Compute aad if any.
+ * - Hash aad and copy to Xi.
+ */
+static void set_aad(struct gcm_ctx *gctx, struct Hash_ctx *hash,
+ unsigned char *aad, int alen)
+{
+ int i;
+ u8 nXi[16] = {0, };
+
+ gctx->aadLen = alen;
+ i = alen & ~0xf;
+ if (i) {
+ gcm_ghash_p8(nXi, hash->Htable+32, aad, i);
+ aad += i;
+ alen -= i;
+ }
+ if (alen) {
+ for (i = 0; i < alen; i++)
+ nXi[i] ^= aad[i];
+
+ memset(gctx->aad_hash, 0, 16);
+ gcm_ghash_p8(gctx->aad_hash, hash->Htable+32, nXi, 16);
+ } else {
+ memcpy(gctx->aad_hash, nXi, 16);
+ }
+
+ memcpy(hash->Htable, gctx->aad_hash, 16);
+}
+
+static void gcmp10_init(struct gcm_ctx *gctx, u8 *iv, unsigned char *rdkey,
+ struct Hash_ctx *hash, u8 *assoc, unsigned int assoclen)
+{
+ __be32 counter = cpu_to_be32(1);
+
+ aes_p8_encrypt(hash->H, hash->H, rdkey);
+ set_subkey(hash->H);
+ gcm_init_htable(hash->Htable+32, hash->H);
+
+ *((__be32 *)(iv+12)) = counter;
+
+ gctx->Plen = 0;
+
+ /*
+ * Encrypt counter vector as iv tag and increment counter.
+ */
+ aes_p8_encrypt(iv, gctx->ivtag, rdkey);
+
+ counter = cpu_to_be32(2);
+ *((__be32 *)(iv+12)) = counter;
+ memcpy(gctx->iv, iv, 16);
+
+ gctx->aadLen = assoclen;
+ memset(gctx->aad_hash, 0, 16);
+ if (assoclen)
+ set_aad(gctx, hash, assoc, assoclen);
+}
+
+static void finish_tag(struct gcm_ctx *gctx, struct Hash_ctx *hash, int len)
+{
+ int i;
+ unsigned char len_ac[16 + PPC_ALIGN];
+ unsigned char *aclen = PTR_ALIGN((void *)len_ac, PPC_ALIGN);
+ __be64 clen = cpu_to_be64(len << 3);
+ __be64 alen = cpu_to_be64(gctx->aadLen << 3);
+
+ if (len == 0 && gctx->aadLen == 0) {
+ memcpy(hash->Htable, gctx->ivtag, 16);
+ return;
+ }
+
+ /*
+ * Len is in bits.
+ */
+ *((__be64 *)(aclen)) = alen;
+ *((__be64 *)(aclen+8)) = clen;
+
+ /*
+ * hash (AAD len and len)
+ */
+ gcm_ghash_p8(hash->Htable, hash->Htable+32, aclen, 16);
+
+ for (i = 0; i < 16; i++)
+ hash->Htable[i] ^= gctx->ivtag[i];
+}
+
+static int set_authsize(struct crypto_aead *tfm, unsigned int authsize)
+{
+ switch (authsize) {
+ case 4:
+ case 8:
+ case 12:
+ case 13:
+ case 14:
+ case 15:
+ case 16:
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int p10_aes_gcm_setkey(struct crypto_aead *aead, const u8 *key,
+ unsigned int keylen)
+{
+ struct crypto_tfm *tfm = crypto_aead_tfm(aead);
+ struct p10_aes_gcm_ctx *ctx = crypto_tfm_ctx(tfm);
+ int ret;
+
+ vsx_begin();
+ ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key);
+ vsx_end();
+
+ return ret ? -EINVAL : 0;
+}
+
+static int p10_aes_gcm_crypt(struct aead_request *req, int enc)
+{
+ struct crypto_tfm *tfm = req->base.tfm;
+ struct p10_aes_gcm_ctx *ctx = crypto_tfm_ctx(tfm);
+ u8 databuf[sizeof(struct gcm_ctx) + PPC_ALIGN];
+ struct gcm_ctx *gctx = PTR_ALIGN((void *)databuf, PPC_ALIGN);
+ u8 hashbuf[sizeof(struct Hash_ctx) + PPC_ALIGN];
+ struct Hash_ctx *hash = PTR_ALIGN((void *)hashbuf, PPC_ALIGN);
+ struct scatter_walk assoc_sg_walk;
+ struct skcipher_walk walk;
+ u8 *assocmem = NULL;
+ u8 *assoc;
+ unsigned int assoclen = req->assoclen;
+ unsigned int cryptlen = req->cryptlen;
+ unsigned char ivbuf[AES_BLOCK_SIZE+PPC_ALIGN];
+ unsigned char *iv = PTR_ALIGN((void *)ivbuf, PPC_ALIGN);
+ int ret;
+ unsigned long auth_tag_len = crypto_aead_authsize(__crypto_aead_cast(tfm));
+ u8 otag[16];
+ int total_processed = 0;
+
+ memset(databuf, 0, sizeof(databuf));
+ memset(hashbuf, 0, sizeof(hashbuf));
+ memset(ivbuf, 0, sizeof(ivbuf));
+ memcpy(iv, req->iv, GCM_IV_SIZE);
+
+ /* Linearize assoc, if not already linear */
+ if (req->src->length >= assoclen && req->src->length) {
+ scatterwalk_start(&assoc_sg_walk, req->src);
+ assoc = scatterwalk_map(&assoc_sg_walk);
+ } else {
+ gfp_t flags = (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
+ GFP_KERNEL : GFP_ATOMIC;
+
+ /* assoc can be any length, so must be on heap */
+ assocmem = kmalloc(assoclen, flags);
+ if (unlikely(!assocmem))
+ return -ENOMEM;
+ assoc = assocmem;
+
+ scatterwalk_map_and_copy(assoc, req->src, 0, assoclen, 0);
+ }
+
+ vsx_begin();
+ gcmp10_init(gctx, iv, (unsigned char *) &ctx->enc_key, hash, assoc, assoclen);
+ vsx_end();
+
+ if (!assocmem)
+ scatterwalk_unmap(assoc);
+ else
+ kfree(assocmem);
+
+ if (enc)
+ ret = skcipher_walk_aead_encrypt(&walk, req, false);
+ else
+ ret = skcipher_walk_aead_decrypt(&walk, req, false);
+ if (ret)
+ return ret;
+
+ while (walk.nbytes > 0 && ret == 0) {
+
+ vsx_begin();
+ if (enc)
+ aes_p10_gcm_encrypt(walk.src.virt.addr,
+ walk.dst.virt.addr,
+ walk.nbytes,
+ &ctx->enc_key, gctx->iv, hash->Htable);
+ else
+ aes_p10_gcm_decrypt(walk.src.virt.addr,
+ walk.dst.virt.addr,
+ walk.nbytes,
+ &ctx->enc_key, gctx->iv, hash->Htable);
+ vsx_end();
+
+ total_processed += walk.nbytes;
+ ret = skcipher_walk_done(&walk, 0);
+ }
+
+ if (ret)
+ return ret;
+
+ /* Finalize hash */
+ vsx_begin();
+ finish_tag(gctx, hash, total_processed);
+ vsx_end();
+
+ /* copy Xi to end of dst */
+ if (enc)
+ scatterwalk_map_and_copy(hash->Htable, req->dst, req->assoclen + cryptlen,
+ auth_tag_len, 1);
+ else {
+ scatterwalk_map_and_copy(otag, req->src,
+ req->assoclen + cryptlen - auth_tag_len,
+ auth_tag_len, 0);
+
+ if (crypto_memneq(otag, hash->Htable, auth_tag_len)) {
+ memzero_explicit(hash->Htable, 16);
+ return -EBADMSG;
+ }
+ }
+
+ return 0;
+}
+
+static int p10_aes_gcm_encrypt(struct aead_request *req)
+{
+ return p10_aes_gcm_crypt(req, 1);
+}
+
+static int p10_aes_gcm_decrypt(struct aead_request *req)
+{
+ return p10_aes_gcm_crypt(req, 0);
+}
+
+static struct aead_alg gcm_aes_alg = {
+ .ivsize = GCM_IV_SIZE,
+ .maxauthsize = 16,
+
+ .setauthsize = set_authsize,
+ .setkey = p10_aes_gcm_setkey,
+ .encrypt = p10_aes_gcm_encrypt,
+ .decrypt = p10_aes_gcm_decrypt,
+
+ .base.cra_name = "gcm(aes)",
+ .base.cra_driver_name = "aes_gcm_p10",
+ .base.cra_priority = 2100,
+ .base.cra_blocksize = 1,
+ .base.cra_ctxsize = sizeof(struct p10_aes_gcm_ctx),
+ .base.cra_module = THIS_MODULE,
+};
+
+static int __init p10_init(void)
+{
+ return crypto_register_aead(&gcm_aes_alg);
+}
+
+static void __exit p10_exit(void)
+{
+ crypto_unregister_aead(&gcm_aes_alg);
+}
+
+module_cpu_feature_match(PPC_MODULE_FEATURE_P10, p10_init);
+module_exit(p10_exit);
projects / platform / kernel / linux-starfive.git / commitdiff