checksum.cpp revision 360784 
1//===-- checksum.cpp --------------------------------------------*- 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#include "checksum.h"
10#include "atomic_helpers.h"
11
12#if defined(__x86_64__) || defined(__i386__)
13#include <cpuid.h>
14#elif defined(__arm__) || defined(__aarch64__)
15#if SCUDO_FUCHSIA
16#include <zircon/features.h>
17#include <zircon/syscalls.h>
18#else
19#include <sys/auxv.h>
20#endif
21#endif
22
23namespace scudo {
24
25Checksum HashAlgorithm = {Checksum::BSD};
26
27#if defined(__x86_64__) || defined(__i386__)
28// i386 and x86_64 specific code to detect CRC32 hardware support via CPUID.
29// CRC32 requires the SSE 4.2 instruction set.
30#ifndef bit_SSE4_2
31#define bit_SSE4_2 bit_SSE42 // clang and gcc have different defines.
32#endif
33
34bool hasHardwareCRC32() {
35  u32 Eax, Ebx = 0, Ecx = 0, Edx = 0;
36  __get_cpuid(0, &Eax, &Ebx, &Ecx, &Edx);
37  const bool IsIntel = (Ebx == signature_INTEL_ebx) &&
38                       (Edx == signature_INTEL_edx) &&
39                       (Ecx == signature_INTEL_ecx);
40  const bool IsAMD = (Ebx == signature_AMD_ebx) && (Edx == signature_AMD_edx) &&
41                     (Ecx == signature_AMD_ecx);
42  if (!IsIntel && !IsAMD)
43    return false;
44  __get_cpuid(1, &Eax, &Ebx, &Ecx, &Edx);
45  return !!(Ecx & bit_SSE4_2);
46}
47#elif defined(__arm__) || defined(__aarch64__)
48#ifndef AT_HWCAP
49#define AT_HWCAP 16
50#endif
51#ifndef HWCAP_CRC32
52#define HWCAP_CRC32 (1U << 7) // HWCAP_CRC32 is missing on older platforms.
53#endif
54
55bool hasHardwareCRC32() {
56#if SCUDO_FUCHSIA
57  u32 HWCap;
58  const zx_status_t Status =
59      zx_system_get_features(ZX_FEATURE_KIND_CPU, &HWCap);
60  if (Status != ZX_OK)
61    return false;
62  return !!(HWCap & ZX_ARM64_FEATURE_ISA_CRC32);
63#else
64  return !!(getauxval(AT_HWCAP) & HWCAP_CRC32);
65#endif // SCUDO_FUCHSIA
66}
67#else
68// No hardware CRC32 implemented in Scudo for other architectures.
69bool hasHardwareCRC32() { return false; }
70#endif // defined(__x86_64__) || defined(__i386__)
71
72} // namespace scudo
73