// SPDX-License-Identifier: BSD-2-Clause
/*
 * Copyright (c) 2017-2020, Linaro Limited
 */

#include <assert.h>
#include <crypto/crypto_accel.h>
#include <crypto/crypto.h>
#include <crypto/ghash-ce-core.h>
#include <crypto/internal_aes-gcm.h>
#include <io.h>
#include <kernel/panic.h>
#include <kernel/thread.h>
#include <string.h>
#include <types_ext.h>

static void get_be_block(void *dst, const void *src)
{
	uint64_t *d = dst;

	d[1] = get_be64(src);
	d[0] = get_be64((const uint8_t *)src + 8);
}

static void put_be_block(void *dst, const void *src)
{
	const uint64_t *s = src;

	put_be64(dst, s[1]);
	put_be64((uint8_t *)dst + 8, s[0]);
}

static void ghash_reflect(uint64_t h[2], const uint64_t k[2])
{
	uint64_t b = get_be64(k);
	uint64_t a = get_be64(k + 1);

	h[0] = (a << 1) | (b >> 63);
	h[1] = (b << 1) | (a >> 63);
	if (b >> 63)
		h[1] ^= 0xc200000000000000UL;
}

void internal_aes_gcm_set_key(struct internal_aes_gcm_state *state,
			      const struct internal_aes_gcm_key *enc_key)
{
	uint64_t k[2] = { 0 };
	uint64_t h[2] = { 0 };

	crypto_aes_enc_block(enc_key->data, sizeof(enc_key->data),
			     enc_key->rounds, state->ctr, k);

	ghash_reflect(state->ghash_key.h, k);

	internal_aes_gcm_gfmul(k, k, h);
	ghash_reflect(state->ghash_key.h2, h);

	internal_aes_gcm_gfmul(k, h, h);
	ghash_reflect(state->ghash_key.h3, h);

	internal_aes_gcm_gfmul(k, h, h);
	ghash_reflect(state->ghash_key.h4, h);
}

void internal_aes_gcm_ghash_update(struct internal_aes_gcm_state *state,
				   const void *head, const void *data,
				   size_t num_blocks)
{
	uint32_t vfp_state;
	uint64_t dg[2];

	get_be_block(dg, state->hash_state);

	vfp_state = thread_kernel_enable_vfp();

#ifdef CFG_HWSUPP_PMULT_64
	pmull_ghash_update_p64(num_blocks, dg, data, &state->ghash_key, head);
#else
	pmull_ghash_update_p8(num_blocks, dg, data, &state->ghash_key, head);
#endif
	thread_kernel_disable_vfp(vfp_state);

	put_be_block(state->hash_state, dg);
}

TEE_Result internal_aes_gcm_expand_enc_key(const void *key, size_t key_len,
					   struct internal_aes_gcm_key *enc_key)
{
	return crypto_accel_aes_expand_keys(key, key_len, enc_key->data, NULL,
					    sizeof(enc_key->data),
					    &enc_key->rounds);
}

#ifdef ARM64
static void update_payload_2block(struct internal_aes_gcm_state *state,
				  const struct internal_aes_gcm_key *ek,
				  TEE_OperationMode mode, const void *src,
				  size_t num_blocks, void *dst)
{
	uint32_t vfp_state;
	uint64_t dg[2];

	assert(num_blocks && !(num_blocks % 2));

	get_be_block(dg, state->hash_state);

	vfp_state = thread_kernel_enable_vfp();

	if (mode == TEE_MODE_ENCRYPT) {
		uint8_t ks[sizeof(state->buf_cryp) * 2] = { 0 };

		/*
		 * ks holds the encrypted counters of the next two blocks.
		 * pmull_gcm_encrypt() uses this to encrypt the first two
		 * blocks. When pmull_gcm_encrypt() returns is ks updated
		 * with the encrypted counters of the next two blocks. As
		 * we're only keeping one of these blocks we throw away
		 * block number two consequently decreases the counter by
		 * one.
		 */
		memcpy(ks, state->buf_cryp, sizeof(state->buf_cryp));

		pmull_gcm_load_round_keys(ek->data, ek->rounds);
		pmull_gcm_encrypt_block(ks + sizeof(state->buf_cryp),
					(uint8_t *)state->ctr, ek->rounds);
		internal_aes_gcm_inc_ctr(state);
		pmull_gcm_encrypt(num_blocks, dg, dst, src, &state->ghash_key,
				  state->ctr, NULL, ek->rounds, ks);
		memcpy(state->buf_cryp, ks, TEE_AES_BLOCK_SIZE);
		internal_aes_gcm_dec_ctr(state);
	} else {
		pmull_gcm_decrypt(num_blocks, dg, dst, src, &state->ghash_key,
				  state->ctr, ek->data, ek->rounds);
	}

	thread_kernel_disable_vfp(vfp_state);

	put_be_block(state->hash_state, dg);
}

/* Overriding the __weak function */
void
internal_aes_gcm_update_payload_blocks(struct internal_aes_gcm_state *state,
				       const struct internal_aes_gcm_key *ek,
				       TEE_OperationMode mode, const void *src,
				       size_t num_blocks, void *dst)
{
	size_t nb = ROUNDDOWN(num_blocks, 2);

	/*
	 * pmull_gcm_encrypt() and pmull_gcm_decrypt() can only handle
	 * blocks in multiples of two.
	 */
	if (nb)
		update_payload_2block(state, ek, mode, src, nb, dst);

	if (nb != num_blocks) {
		/* There's a final block */
		const void *s = (const uint8_t *)src + nb * TEE_AES_BLOCK_SIZE;
		void *d = (uint8_t *)dst + nb * TEE_AES_BLOCK_SIZE;
		uint64_t tmp[2] = { 0 };

		if (!ALIGNMENT_IS_OK(s, uint64_t)) {
			memcpy(tmp, s, sizeof(tmp));
			s = tmp;
		}

		if (mode == TEE_MODE_ENCRYPT)
			internal_aes_gcm_encrypt_block(state, ek, s, d);
		else
			internal_aes_gcm_decrypt_block(state, ek, s, d);
	}
}
#endif /*ARM64*/