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#include "chunk.h"
12
13#if defined(__x86_64__) || defined(__i386__)
14#include <cpuid.h>
15#elif defined(__arm__) || defined(__aarch64__)
16#if SCUDO_FUCHSIA
17#include <zircon/features.h>
18#include <zircon/syscalls.h>
19#else
20#include <sys/auxv.h>
21#endif
22#endif
23
24namespace scudo {
25
26Checksum HashAlgorithm = {Checksum::BSD};
27
28#if defined(__x86_64__) || defined(__i386__)
29// i386 and x86_64 specific code to detect CRC32 hardware support via CPUID.
30// CRC32 requires the SSE 4.2 instruction set.
31#ifndef bit_SSE4_2
32#define bit_SSE4_2 bit_SSE42 // clang and gcc have different defines.
33#endif
34
35#ifndef signature_HYGON_ebx // They are not defined in gcc.
36// HYGON: "HygonGenuine".
37#define signature_HYGON_ebx 0x6f677948
38#define signature_HYGON_edx 0x6e65476e
39#define signature_HYGON_ecx 0x656e6975
40#endif
41
42bool hasHardwareCRC32() {
43  u32 Eax, Ebx = 0, Ecx = 0, Edx = 0;
44  __get_cpuid(0, &Eax, &Ebx, &Ecx, &Edx);
45  const bool IsIntel = (Ebx == signature_INTEL_ebx) &&
46                       (Edx == signature_INTEL_edx) &&
47                       (Ecx == signature_INTEL_ecx);
48  const bool IsAMD = (Ebx == signature_AMD_ebx) && (Edx == signature_AMD_edx) &&
49                     (Ecx == signature_AMD_ecx);
50  const bool IsHygon = (Ebx == signature_HYGON_ebx) &&
51                       (Edx == signature_HYGON_edx) &&
52                       (Ecx == signature_HYGON_ecx);
53  if (!IsIntel && !IsAMD && !IsHygon)
54    return false;
55  __get_cpuid(1, &Eax, &Ebx, &Ecx, &Edx);
56  return !!(Ecx & bit_SSE4_2);
57}
58#elif defined(__arm__) || defined(__aarch64__)
59#ifndef AT_HWCAP
60#define AT_HWCAP 16
61#endif
62#ifndef HWCAP_CRC32
63#define HWCAP_CRC32 (1U << 7) // HWCAP_CRC32 is missing on older platforms.
64#endif
65
66bool hasHardwareCRC32() {
67#if SCUDO_FUCHSIA
68  u32 HWCap;
69  const zx_status_t Status =
70      zx_system_get_features(ZX_FEATURE_KIND_CPU, &HWCap);
71  if (Status != ZX_OK)
72    return false;
73  return !!(HWCap & ZX_ARM64_FEATURE_ISA_CRC32);
74#else
75  return !!(getauxval(AT_HWCAP) & HWCAP_CRC32);
76#endif // SCUDO_FUCHSIA
77}
78#else
79// No hardware CRC32 implemented in Scudo for other architectures.
80bool hasHardwareCRC32() { return false; }
81#endif // defined(__x86_64__) || defined(__i386__)
82
83} // namespace scudo
84