276 lines
6.8 KiB
C
276 lines
6.8 KiB
C
/*
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* Glue code for SHA-256 implementation for SPE instructions (PPC)
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*
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* Based on generic implementation. The assembler module takes care
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* about the SPE registers so it can run from interrupt context.
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*
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* Copyright (c) 2015 Markus Stockhausen <stockhausen@collogia.de>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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#include <crypto/internal/hash.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <linux/cryptohash.h>
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#include <linux/types.h>
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#include <crypto/sha.h>
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#include <asm/byteorder.h>
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#include <asm/switch_to.h>
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#include <linux/hardirq.h>
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/*
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* MAX_BYTES defines the number of bytes that are allowed to be processed
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* between preempt_disable() and preempt_enable(). SHA256 takes ~2,000
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* operations per 64 bytes. e500 cores can issue two arithmetic instructions
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* per clock cycle using one 32/64 bit unit (SU1) and one 32 bit unit (SU2).
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* Thus 1KB of input data will need an estimated maximum of 18,000 cycles.
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* Headroom for cache misses included. Even with the low end model clocked
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* at 667 MHz this equals to a critical time window of less than 27us.
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*
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*/
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#define MAX_BYTES 1024
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extern void ppc_spe_sha256_transform(u32 *state, const u8 *src, u32 blocks);
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static void spe_begin(void)
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{
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/* We just start SPE operations and will save SPE registers later. */
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preempt_disable();
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enable_kernel_spe();
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}
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static void spe_end(void)
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{
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/* reenable preemption */
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preempt_enable();
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}
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static inline void ppc_sha256_clear_context(struct sha256_state *sctx)
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{
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int count = sizeof(struct sha256_state) >> 2;
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u32 *ptr = (u32 *)sctx;
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/* make sure we can clear the fast way */
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BUILD_BUG_ON(sizeof(struct sha256_state) % 4);
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do { *ptr++ = 0; } while (--count);
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}
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static int ppc_spe_sha256_init(struct shash_desc *desc)
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{
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struct sha256_state *sctx = shash_desc_ctx(desc);
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sctx->state[0] = SHA256_H0;
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sctx->state[1] = SHA256_H1;
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sctx->state[2] = SHA256_H2;
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sctx->state[3] = SHA256_H3;
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sctx->state[4] = SHA256_H4;
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sctx->state[5] = SHA256_H5;
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sctx->state[6] = SHA256_H6;
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sctx->state[7] = SHA256_H7;
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sctx->count = 0;
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return 0;
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}
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static int ppc_spe_sha224_init(struct shash_desc *desc)
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{
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struct sha256_state *sctx = shash_desc_ctx(desc);
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sctx->state[0] = SHA224_H0;
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sctx->state[1] = SHA224_H1;
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sctx->state[2] = SHA224_H2;
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sctx->state[3] = SHA224_H3;
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sctx->state[4] = SHA224_H4;
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sctx->state[5] = SHA224_H5;
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sctx->state[6] = SHA224_H6;
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sctx->state[7] = SHA224_H7;
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sctx->count = 0;
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return 0;
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}
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static int ppc_spe_sha256_update(struct shash_desc *desc, const u8 *data,
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unsigned int len)
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{
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struct sha256_state *sctx = shash_desc_ctx(desc);
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const unsigned int offset = sctx->count & 0x3f;
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const unsigned int avail = 64 - offset;
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unsigned int bytes;
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const u8 *src = data;
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if (avail > len) {
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sctx->count += len;
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memcpy((char *)sctx->buf + offset, src, len);
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return 0;
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}
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sctx->count += len;
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if (offset) {
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memcpy((char *)sctx->buf + offset, src, avail);
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spe_begin();
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ppc_spe_sha256_transform(sctx->state, (const u8 *)sctx->buf, 1);
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spe_end();
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len -= avail;
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src += avail;
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}
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while (len > 63) {
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/* cut input data into smaller blocks */
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bytes = (len > MAX_BYTES) ? MAX_BYTES : len;
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bytes = bytes & ~0x3f;
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spe_begin();
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ppc_spe_sha256_transform(sctx->state, src, bytes >> 6);
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spe_end();
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src += bytes;
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len -= bytes;
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};
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memcpy((char *)sctx->buf, src, len);
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return 0;
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}
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static int ppc_spe_sha256_final(struct shash_desc *desc, u8 *out)
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{
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struct sha256_state *sctx = shash_desc_ctx(desc);
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const unsigned int offset = sctx->count & 0x3f;
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char *p = (char *)sctx->buf + offset;
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int padlen;
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__be64 *pbits = (__be64 *)(((char *)&sctx->buf) + 56);
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__be32 *dst = (__be32 *)out;
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padlen = 55 - offset;
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*p++ = 0x80;
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spe_begin();
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if (padlen < 0) {
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memset(p, 0x00, padlen + sizeof (u64));
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ppc_spe_sha256_transform(sctx->state, sctx->buf, 1);
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p = (char *)sctx->buf;
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padlen = 56;
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}
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memset(p, 0, padlen);
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*pbits = cpu_to_be64(sctx->count << 3);
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ppc_spe_sha256_transform(sctx->state, sctx->buf, 1);
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spe_end();
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dst[0] = cpu_to_be32(sctx->state[0]);
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dst[1] = cpu_to_be32(sctx->state[1]);
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dst[2] = cpu_to_be32(sctx->state[2]);
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dst[3] = cpu_to_be32(sctx->state[3]);
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dst[4] = cpu_to_be32(sctx->state[4]);
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dst[5] = cpu_to_be32(sctx->state[5]);
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dst[6] = cpu_to_be32(sctx->state[6]);
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dst[7] = cpu_to_be32(sctx->state[7]);
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ppc_sha256_clear_context(sctx);
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return 0;
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}
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static int ppc_spe_sha224_final(struct shash_desc *desc, u8 *out)
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{
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u32 D[SHA256_DIGEST_SIZE >> 2];
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__be32 *dst = (__be32 *)out;
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ppc_spe_sha256_final(desc, (u8 *)D);
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/* avoid bytewise memcpy */
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dst[0] = D[0];
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dst[1] = D[1];
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dst[2] = D[2];
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dst[3] = D[3];
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dst[4] = D[4];
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dst[5] = D[5];
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dst[6] = D[6];
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/* clear sensitive data */
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memzero_explicit(D, SHA256_DIGEST_SIZE);
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return 0;
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}
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static int ppc_spe_sha256_export(struct shash_desc *desc, void *out)
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{
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struct sha256_state *sctx = shash_desc_ctx(desc);
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memcpy(out, sctx, sizeof(*sctx));
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return 0;
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}
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static int ppc_spe_sha256_import(struct shash_desc *desc, const void *in)
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{
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struct sha256_state *sctx = shash_desc_ctx(desc);
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memcpy(sctx, in, sizeof(*sctx));
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return 0;
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}
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static struct shash_alg algs[2] = { {
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.digestsize = SHA256_DIGEST_SIZE,
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.init = ppc_spe_sha256_init,
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.update = ppc_spe_sha256_update,
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.final = ppc_spe_sha256_final,
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.export = ppc_spe_sha256_export,
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.import = ppc_spe_sha256_import,
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.descsize = sizeof(struct sha256_state),
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.statesize = sizeof(struct sha256_state),
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.base = {
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.cra_name = "sha256",
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.cra_driver_name= "sha256-ppc-spe",
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.cra_priority = 300,
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.cra_flags = CRYPTO_ALG_TYPE_SHASH,
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.cra_blocksize = SHA256_BLOCK_SIZE,
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.cra_module = THIS_MODULE,
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}
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}, {
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.digestsize = SHA224_DIGEST_SIZE,
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.init = ppc_spe_sha224_init,
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.update = ppc_spe_sha256_update,
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.final = ppc_spe_sha224_final,
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.export = ppc_spe_sha256_export,
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.import = ppc_spe_sha256_import,
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.descsize = sizeof(struct sha256_state),
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.statesize = sizeof(struct sha256_state),
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.base = {
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.cra_name = "sha224",
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.cra_driver_name= "sha224-ppc-spe",
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.cra_priority = 300,
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.cra_flags = CRYPTO_ALG_TYPE_SHASH,
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.cra_blocksize = SHA224_BLOCK_SIZE,
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.cra_module = THIS_MODULE,
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}
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} };
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static int __init ppc_spe_sha256_mod_init(void)
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{
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return crypto_register_shashes(algs, ARRAY_SIZE(algs));
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}
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static void __exit ppc_spe_sha256_mod_fini(void)
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{
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crypto_unregister_shashes(algs, ARRAY_SIZE(algs));
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}
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module_init(ppc_spe_sha256_mod_init);
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module_exit(ppc_spe_sha256_mod_fini);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("SHA-224 and SHA-256 Secure Hash Algorithm, SPE optimized");
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MODULE_ALIAS_CRYPTO("sha224");
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MODULE_ALIAS_CRYPTO("sha224-ppc-spe");
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MODULE_ALIAS_CRYPTO("sha256");
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MODULE_ALIAS_CRYPTO("sha256-ppc-spe");
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