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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Glue code for SHA-1 implementation for SPE instructions (PPC)
*
* Based on generic implementation.
*
* Copyright (c) 2015 Markus Stockhausen <stockhausen@collogia.de>
*/
#include <asm/switch_to.h>
#include <crypto/internal/hash.h>
#include <crypto/sha1.h>
#include <crypto/sha1_base.h>
#include <linux/kernel.h>
#include <linux/preempt.h>
#include <linux/module.h>
/*
* MAX_BYTES defines the number of bytes that are allowed to be processed
* between preempt_disable() and preempt_enable(). SHA1 takes ~1000
* operations per 64 bytes. e500 cores can issue two arithmetic instructions
* per clock cycle using one 32/64 bit unit (SU1) and one 32 bit unit (SU2).
* Thus 2KB of input data will need an estimated maximum of 18,000 cycles.
* Headroom for cache misses included. Even with the low end model clocked
* at 667 MHz this equals to a critical time window of less than 27us.
*
*/
#define MAX_BYTES 2048
asmlinkage void ppc_spe_sha1_transform(u32 *state, const u8 *src, u32 blocks);
static void spe_begin(void)
{
/* We just start SPE operations and will save SPE registers later. */
preempt_disable();
enable_kernel_spe();
}
static void spe_end(void)
{
disable_kernel_spe();
/* reenable preemption */
preempt_enable();
}
static void ppc_spe_sha1_block(struct sha1_state *sctx, const u8 *src,
int blocks)
{
do {
int unit = min(blocks, MAX_BYTES / SHA1_BLOCK_SIZE);
spe_begin();
ppc_spe_sha1_transform(sctx->state, src, unit);
spe_end();
src += unit * SHA1_BLOCK_SIZE;
blocks -= unit;
} while (blocks);
}
static int ppc_spe_sha1_update(struct shash_desc *desc, const u8 *data,
unsigned int len)
{
return sha1_base_do_update_blocks(desc, data, len, ppc_spe_sha1_block);
}
static int ppc_spe_sha1_finup(struct shash_desc *desc, const u8 *src,
unsigned int len, u8 *out)
{
sha1_base_do_finup(desc, src, len, ppc_spe_sha1_block);
return sha1_base_finish(desc, out);
}
static struct shash_alg alg = {
.digestsize = SHA1_DIGEST_SIZE,
.init = sha1_base_init,
.update = ppc_spe_sha1_update,
.finup = ppc_spe_sha1_finup,
.descsize = SHA1_STATE_SIZE,
.base = {
.cra_name = "sha1",
.cra_driver_name= "sha1-ppc-spe",
.cra_priority = 300,
.cra_flags = CRYPTO_AHASH_ALG_BLOCK_ONLY,
.cra_blocksize = SHA1_BLOCK_SIZE,
.cra_module = THIS_MODULE,
}
};
static int __init ppc_spe_sha1_mod_init(void)
{
return crypto_register_shash(&alg);
}
static void __exit ppc_spe_sha1_mod_fini(void)
{
crypto_unregister_shash(&alg);
}
module_init(ppc_spe_sha1_mod_init);
module_exit(ppc_spe_sha1_mod_fini);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm, SPE optimized");
MODULE_ALIAS_CRYPTO("sha1");
MODULE_ALIAS_CRYPTO("sha1-ppc-spe");
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