Dynamic Tools Team | 517193e | 2019-09-11 14:48:41 +0000 | [diff] [blame] | 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-exception |
| 6 | // |
| 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: -msse4.2 |
| 16 | // - for ARM & AArch64: -march=armv8-a+crc or -mcrc |
| 17 | // An additional check must be performed at runtime as well to make sure the |
| 18 | // emitted instructions are valid on the target host. |
| 19 | |
| 20 | #ifdef __SSE4_2__ |
| 21 | #include <smmintrin.h> |
| 22 | #define CRC32_INTRINSIC FIRST_32_SECOND_64(_mm_crc32_u32, _mm_crc32_u64) |
| 23 | #endif |
| 24 | #ifdef __ARM_FEATURE_CRC32 |
| 25 | #include <arm_acle.h> |
| 26 | #define CRC32_INTRINSIC FIRST_32_SECOND_64(__crc32cw, __crc32cd) |
| 27 | #endif |
| 28 | |
| 29 | namespace scudo { |
| 30 | |
| 31 | enum class Checksum : u8 { |
| 32 | BSD = 0, |
| 33 | HardwareCRC32 = 1, |
| 34 | }; |
| 35 | |
| 36 | // BSD checksum, unlike a software CRC32, doesn't use any array lookup. We save |
| 37 | // significantly on memory accesses, as well as 1K of CRC32 table, on platforms |
| 38 | // that do no support hardware CRC32. The checksum itself is 16-bit, which is at |
| 39 | // odds with CRC32, but enough for our needs. |
Dynamic Tools Team | 09e6d48 | 2019-11-26 18:18:14 -0800 | [diff] [blame] | 40 | inline u16 computeBSDChecksum(u16 Sum, uptr Data) { |
Dynamic Tools Team | 517193e | 2019-09-11 14:48:41 +0000 | [diff] [blame] | 41 | for (u8 I = 0; I < sizeof(Data); I++) { |
| 42 | Sum = static_cast<u16>((Sum >> 1) | ((Sum & 1) << 15)); |
| 43 | Sum = static_cast<u16>(Sum + (Data & 0xff)); |
| 44 | Data >>= 8; |
| 45 | } |
| 46 | return Sum; |
| 47 | } |
| 48 | |
| 49 | bool hasHardwareCRC32(); |
| 50 | WEAK u32 computeHardwareCRC32(u32 Crc, uptr Data); |
| 51 | |
| 52 | } // namespace scudo |
| 53 | |
| 54 | #endif // SCUDO_CHECKSUM_H_ |