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1//===-- checksum.h ----------------------------------------------*- C++ -*-===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef SCUDO_CHECKSUM_H_10#define SCUDO_CHECKSUM_H_11 12#include "internal_defs.h"13 14// Hardware CRC32 is supported at compilation via the following:15// - for i386 & x86_64: -mcrc32 (earlier: -msse4.2)16// - for ARM & AArch64: -march=armv8-a+crc or -mcrc17// An additional check must be performed at runtime as well to make sure the18// emitted instructions are valid on the target host.19 20#if defined(__CRC32__)21// NB: clang has <crc32intrin.h> but GCC does not22#include <smmintrin.h>23#define CRC32_INTRINSIC \24 FIRST_32_SECOND_64(__builtin_ia32_crc32si, __builtin_ia32_crc32di)25#elif defined(__SSE4_2__)26#include <smmintrin.h>27#define CRC32_INTRINSIC FIRST_32_SECOND_64(_mm_crc32_u32, _mm_crc32_u64)28#endif29#ifdef __ARM_FEATURE_CRC3230#include <arm_acle.h>31#define CRC32_INTRINSIC FIRST_32_SECOND_64(__crc32cw, __crc32cd)32#endif33#ifdef __loongarch__34#include <larchintrin.h>35#define CRC32_INTRINSIC FIRST_32_SECOND_64(__crcc_w_w_w, __crcc_w_d_w)36#endif37 38namespace scudo {39 40enum class Checksum : u8 {41 BSD = 0,42 HardwareCRC32 = 1,43};44 45// BSD checksum, unlike a software CRC32, doesn't use any array lookup. We save46// significantly on memory accesses, as well as 1K of CRC32 table, on platforms47// that do no support hardware CRC32. The checksum itself is 16-bit, which is at48// odds with CRC32, but enough for our needs.49inline u16 computeBSDChecksum(u16 Sum, uptr Data) {50 for (u8 I = 0; I < sizeof(Data); I++) {51 Sum = static_cast<u16>((Sum >> 1) | ((Sum & 1) << 15));52 Sum = static_cast<u16>(Sum + (Data & 0xff));53 Data >>= 8;54 }55 return Sum;56}57 58bool hasHardwareCRC32();59WEAK u32 computeHardwareCRC32(u32 Crc, uptr Data);60 61} // namespace scudo62 63#endif // SCUDO_CHECKSUM_H_64