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// Copyright (c) 2018, Arm Limited and affiliates. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#include "util/crc32c_arm64.h"
#if defined(__linux__) && defined(HAVE_ARM64_CRC)
#include <asm/hwcap.h>
#ifdef ROCKSDB_AUXV_GETAUXVAL_PRESENT
#include <sys/auxv.h>
#endif
#ifndef HWCAP_CRC32
#define HWCAP_CRC32 (1 << 7)
#endif
#ifndef HWCAP_PMULL
#define HWCAP_PMULL (1 << 4)
#endif
#ifdef HAVE_ARM64_CRYPTO
/* unfolding to compute 8 * 3 = 24 bytes parallelly */
#define CRC32C24BYTES(ITR) \
crc1 = crc32c_u64(crc1, *(buf64 + BLK_LENGTH + (ITR))); \
crc2 = crc32c_u64(crc2, *(buf64 + BLK_LENGTH * 2 + (ITR))); \
crc0 = crc32c_u64(crc0, *(buf64 + (ITR)));
/* unfolding to compute 24 * 7 = 168 bytes parallelly */
#define CRC32C7X24BYTES(ITR) \
do { \
CRC32C24BYTES((ITR)*7 + 0) \
CRC32C24BYTES((ITR)*7 + 1) \
CRC32C24BYTES((ITR)*7 + 2) \
CRC32C24BYTES((ITR)*7 + 3) \
CRC32C24BYTES((ITR)*7 + 4) \
CRC32C24BYTES((ITR)*7 + 5) \
CRC32C24BYTES((ITR)*7 + 6) \
} while (0)
#endif
extern bool pmull_runtime_flag;
uint32_t crc32c_runtime_check(void) {
#ifdef ROCKSDB_AUXV_GETAUXVAL_PRESENT
uint64_t auxv = getauxval(AT_HWCAP);
return (auxv & HWCAP_CRC32) != 0;
#else
return 0;
#endif
}
bool crc32c_pmull_runtime_check(void) {
#ifdef ROCKSDB_AUXV_GETAUXVAL_PRESENT
uint64_t auxv = getauxval(AT_HWCAP);
return (auxv & HWCAP_PMULL) != 0;
#else
return false;
#endif
}
#ifdef ROCKSDB_UBSAN_RUN
#if defined(__clang__)
__attribute__((__no_sanitize__("alignment")))
#elif defined(__GNUC__)
__attribute__((__no_sanitize_undefined__))
#endif
#endif
uint32_t crc32c_arm64(uint32_t crc, unsigned char const *data,
unsigned len) {
const uint8_t *buf8;
const uint64_t *buf64 = (uint64_t *)data;
int length = (int)len;
crc ^= 0xffffffff;
/*
* Pmull runtime check here.
* Raspberry Pi supports crc32 but doesn't support pmull.
* Skip Crc32c Parallel computation if no crypto extension available.
*/
if (pmull_runtime_flag) {
/* Macro (HAVE_ARM64_CRYPTO) is used for compiling check */
#ifdef HAVE_ARM64_CRYPTO
/* Crc32c Parallel computation
* Algorithm comes from Intel whitepaper:
* crc-iscsi-polynomial-crc32-instruction-paper
*
* Input data is divided into three equal-sized blocks
* Three parallel blocks (crc0, crc1, crc2) for 1024 Bytes
* One Block: 42(BLK_LENGTH) * 8(step length: crc32c_u64) bytes
*/
#define BLK_LENGTH 42
while (length >= 1024) {
uint64_t t0, t1;
uint32_t crc0 = 0, crc1 = 0, crc2 = 0;
/* Parallel Param:
* k0 = CRC32(x ^ (42 * 8 * 8 * 2 - 1));
* k1 = CRC32(x ^ (42 * 8 * 8 - 1));
*/
uint32_t k0 = 0xe417f38a, k1 = 0x8f158014;
/* Prefetch data for following block to avoid cache miss */
PREF1KL1((uint8_t *)buf64, 1024);
/* First 8 byte for better pipelining */
crc0 = crc32c_u64(crc, *buf64++);
/* 3 blocks crc32c parallel computation
* Macro unfolding to compute parallelly
* 168 * 6 = 1008 (bytes)
*/
CRC32C7X24BYTES(0);
CRC32C7X24BYTES(1);
CRC32C7X24BYTES(2);
CRC32C7X24BYTES(3);
CRC32C7X24BYTES(4);
CRC32C7X24BYTES(5);
buf64 += (BLK_LENGTH * 3);
/* Last 8 bytes */
crc = crc32c_u64(crc2, *buf64++);
t0 = (uint64_t)vmull_p64(crc0, k0);
t1 = (uint64_t)vmull_p64(crc1, k1);
/* Merge (crc0, crc1, crc2) -> crc */
crc1 = crc32c_u64(0, t1);
crc ^= crc1;
crc0 = crc32c_u64(0, t0);
crc ^= crc0;
length -= 1024;
}
if (length == 0) return crc ^ (0xffffffffU);
#endif
} // if Pmull runtime check here
buf8 = (const uint8_t *)buf64;
while (length >= 8) {
crc = crc32c_u64(crc, *(const uint64_t *)buf8);
buf8 += 8;
length -= 8;
}
/* The following is more efficient than the straight loop */
if (length >= 4) {
crc = crc32c_u32(crc, *(const uint32_t *)buf8);
buf8 += 4;
length -= 4;
}
if (length >= 2) {
crc = crc32c_u16(crc, *(const uint16_t *)buf8);
buf8 += 2;
length -= 2;
}
if (length >= 1) crc = crc32c_u8(crc, *buf8);
crc ^= 0xffffffff;
return crc;
}
#endif
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