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/*
* Accelerated CRC32(C) using ARM CRC, NEON and Crypto Extensions instructions
*
* Copyright (C) 2016 Linaro Ltd <ard.biesheuvel@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/cpufeature.h>
#include <linux/crc32.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/string.h>
#include <crypto/internal/hash.h>
#include <asm/hwcap.h>
#include <asm/neon.h>
#include <asm/simd.h>
#include <asm/unaligned.h>
#define PMULL_MIN_LEN 64L /* minimum size of buffer
* for crc32_pmull_le_16 */
#define SCALE_F 16L /* size of NEON register */
asmlinkage u32 crc32_pmull_le(const u8 buf[], u32 len, u32 init_crc);
asmlinkage u32 crc32_armv8_le(u32 init_crc, const u8 buf[], u32 len);
asmlinkage u32 crc32c_pmull_le(const u8 buf[], u32 len, u32 init_crc);
asmlinkage u32 crc32c_armv8_le(u32 init_crc, const u8 buf[], u32 len);
static u32 (*fallback_crc32)(u32 init_crc, const u8 buf[], u32 len);
static u32 (*fallback_crc32c)(u32 init_crc, const u8 buf[], u32 len);
static int crc32_cra_init(struct crypto_tfm *tfm)
{
u32 *key = crypto_tfm_ctx(tfm);
*key = 0;
return 0;
}
static int crc32c_cra_init(struct crypto_tfm *tfm)
{
u32 *key = crypto_tfm_ctx(tfm);
*key = ~0;
return 0;
}
static int crc32_setkey(struct crypto_shash *hash, const u8 *key,
unsigned int keylen)
{
u32 *mctx = crypto_shash_ctx(hash);
if (keylen != sizeof(u32)) {
crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN);
return -EINVAL;
}
*mctx = le32_to_cpup((__le32 *)key);
return 0;
}
static int crc32_init(struct shash_desc *desc)
{
u32 *mctx = crypto_shash_ctx(desc->tfm);
u32 *crc = shash_desc_ctx(desc);
*crc = *mctx;
return 0;
}
static int crc32_update(struct shash_desc *desc, const u8 *data,
unsigned int length)
{
u32 *crc = shash_desc_ctx(desc);
*crc = crc32_armv8_le(*crc, data, length);
return 0;
}
static int crc32c_update(struct shash_desc *desc, const u8 *data,
unsigned int length)
{
u32 *crc = shash_desc_ctx(desc);
*crc = crc32c_armv8_le(*crc, data, length);
return 0;
}
static int crc32_final(struct shash_desc *desc, u8 *out)
{
u32 *crc = shash_desc_ctx(desc);
put_unaligned_le32(*crc, out);
return 0;
}
static int crc32c_final(struct shash_desc *desc, u8 *out)
{
u32 *crc = shash_desc_ctx(desc);
put_unaligned_le32(~*crc, out);
return 0;
}
static int crc32_pmull_update(struct shash_desc *desc, const u8 *data,
unsigned int length)
{
u32 *crc = shash_desc_ctx(desc);
unsigned int l;
if (may_use_simd()) {
if ((u32)data % SCALE_F) {
l = min_t(u32, length, SCALE_F - ((u32)data % SCALE_F));
*crc = fallback_crc32(*crc, data, l);
data += l;
length -= l;
}
if (length >= PMULL_MIN_LEN) {
l = round_down(length, SCALE_F);
kernel_neon_begin();
*crc = crc32_pmull_le(data, l, *crc);
kernel_neon_end();
data += l;
length -= l;
}
}
if (length > 0)
*crc = fallback_crc32(*crc, data, length);
return 0;
}
static int crc32c_pmull_update(struct shash_desc *desc, const u8 *data,
unsigned int length)
{
u32 *crc = shash_desc_ctx(desc);
unsigned int l;
if (may_use_simd()) {
if ((u32)data % SCALE_F) {
l = min_t(u32, length, SCALE_F - ((u32)data % SCALE_F));
*crc = fallback_crc32c(*crc, data, l);
data += l;
length -= l;
}
if (length >= PMULL_MIN_LEN) {
l = round_down(length, SCALE_F);
kernel_neon_begin();
*crc = crc32c_pmull_le(data, l, *crc);
kernel_neon_end();
data += l;
length -= l;
}
}
if (length > 0)
*crc = fallback_crc32c(*crc, data, length);
return 0;
}
static struct shash_alg crc32_pmull_algs[] = { {
.setkey = crc32_setkey,
.init = crc32_init,
.update = crc32_update,
.final = crc32_final,
.descsize = sizeof(u32),
.digestsize = sizeof(u32),
.base.cra_ctxsize = sizeof(u32),
.base.cra_init = crc32_cra_init,
.base.cra_name = "crc32",
.base.cra_driver_name = "crc32-arm-ce",
.base.cra_priority = 200,
.base.cra_blocksize = 1,
.base.cra_module = THIS_MODULE,
}, {
.setkey = crc32_setkey,
.init = crc32_init,
.update = crc32c_update,
.final = crc32c_final,
.descsize = sizeof(u32),
.digestsize = sizeof(u32),
.base.cra_ctxsize = sizeof(u32),
.base.cra_init = crc32c_cra_init,
.base.cra_name = "crc32c",
.base.cra_driver_name = "crc32c-arm-ce",
.base.cra_priority = 200,
.base.cra_blocksize = 1,
.base.cra_module = THIS_MODULE,
} };
static int __init crc32_pmull_mod_init(void)
{
if (elf_hwcap2 & HWCAP2_PMULL) {
crc32_pmull_algs[0].update = crc32_pmull_update;
crc32_pmull_algs[1].update = crc32c_pmull_update;
if (elf_hwcap2 & HWCAP2_CRC32) {
fallback_crc32 = crc32_armv8_le;
fallback_crc32c = crc32c_armv8_le;
} else {
fallback_crc32 = crc32_le;
fallback_crc32c = __crc32c_le;
}
} else if (!(elf_hwcap2 & HWCAP2_CRC32)) {
return -ENODEV;
}
return crypto_register_shashes(crc32_pmull_algs,
ARRAY_SIZE(crc32_pmull_algs));
}
static void __exit crc32_pmull_mod_exit(void)
{
crypto_unregister_shashes(crc32_pmull_algs,
ARRAY_SIZE(crc32_pmull_algs));
}
static const struct cpu_feature crc32_cpu_feature[] = {
{ cpu_feature(CRC32) }, { cpu_feature(PMULL) }, { }
};
MODULE_DEVICE_TABLE(cpu, crc32_cpu_feature);
module_init(crc32_pmull_mod_init);
module_exit(crc32_pmull_mod_exit);
MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS_CRYPTO("crc32");
MODULE_ALIAS_CRYPTO("crc32c");
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