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
23 namespace scudo {
24
25 Checksum 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
hasHardwareCRC32()34 bool 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
hasHardwareCRC32()55 bool 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.
hasHardwareCRC32()69 bool hasHardwareCRC32() { return false; }
70 #endif // defined(__x86_64__) || defined(__i386__)
71
72 } // namespace scudo
73