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 24 namespace scudo { 25 26 Checksum 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 42 bool 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 66 bool 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. 80 bool hasHardwareCRC32() { return false; } 81 #endif // defined(__x86_64__) || defined(__i386__) 82 83 } // namespace scudo 84