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 #elif defined(__loongarch__)
23 #include <sys/auxv.h>
24 #endif
25
26 namespace scudo {
27
28 Checksum HashAlgorithm = {Checksum::BSD};
29
30 #if defined(__x86_64__) || defined(__i386__)
31 // i386 and x86_64 specific code to detect CRC32 hardware support via CPUID.
32 // CRC32 requires the SSE 4.2 instruction set.
33 #ifndef bit_SSE4_2
34 #define bit_SSE4_2 bit_SSE42 // clang and gcc have different defines.
35 #endif
36
37 #ifndef signature_HYGON_ebx // They are not defined in gcc.
38 // HYGON: "HygonGenuine".
39 #define signature_HYGON_ebx 0x6f677948
40 #define signature_HYGON_edx 0x6e65476e
41 #define signature_HYGON_ecx 0x656e6975
42 #endif
43
hasHardwareCRC32()44 bool hasHardwareCRC32() {
45 u32 Eax, Ebx = 0, Ecx = 0, Edx = 0;
46 __get_cpuid(0, &Eax, &Ebx, &Ecx, &Edx);
47 const bool IsIntel = (Ebx == signature_INTEL_ebx) &&
48 (Edx == signature_INTEL_edx) &&
49 (Ecx == signature_INTEL_ecx);
50 const bool IsAMD = (Ebx == signature_AMD_ebx) && (Edx == signature_AMD_edx) &&
51 (Ecx == signature_AMD_ecx);
52 const bool IsHygon = (Ebx == signature_HYGON_ebx) &&
53 (Edx == signature_HYGON_edx) &&
54 (Ecx == signature_HYGON_ecx);
55 if (!IsIntel && !IsAMD && !IsHygon)
56 return false;
57 __get_cpuid(1, &Eax, &Ebx, &Ecx, &Edx);
58 return !!(Ecx & bit_SSE4_2);
59 }
60 #elif defined(__arm__) || defined(__aarch64__)
61 #ifndef AT_HWCAP
62 #define AT_HWCAP 16
63 #endif
64 #ifndef HWCAP_CRC32
65 #define HWCAP_CRC32 (1U << 7) // HWCAP_CRC32 is missing on older platforms.
66 #endif
67
hasHardwareCRC32()68 bool hasHardwareCRC32() {
69 #if SCUDO_FUCHSIA
70 u32 HWCap;
71 const zx_status_t Status =
72 zx_system_get_features(ZX_FEATURE_KIND_CPU, &HWCap);
73 if (Status != ZX_OK)
74 return false;
75 return !!(HWCap & ZX_ARM64_FEATURE_ISA_CRC32);
76 #else
77 return !!(getauxval(AT_HWCAP) & HWCAP_CRC32);
78 #endif // SCUDO_FUCHSIA
79 }
80 #elif defined(__loongarch__)
81 // The definition is only pulled in by <sys/auxv.h> since glibc 2.38, so
82 // supply it if missing.
83 #ifndef HWCAP_LOONGARCH_CRC32
84 #define HWCAP_LOONGARCH_CRC32 (1 << 6)
85 #endif
86 // Query HWCAP for platform capability, according to *Software Development and
87 // Build Convention for LoongArch Architectures* v0.1, Section 9.1.
88 //
89 // Link:
90 // https://github.com/loongson/la-softdev-convention/blob/v0.1/la-softdev-convention.adoc#kernel-development
hasHardwareCRC32()91 bool hasHardwareCRC32() {
92 return !!(getauxval(AT_HWCAP) & HWCAP_LOONGARCH_CRC32);
93 }
94 #else
95 // No hardware CRC32 implemented in Scudo for other architectures.
hasHardwareCRC32()96 bool hasHardwareCRC32() { return false; }
97 #endif // defined(__x86_64__) || defined(__i386__)
98
99 } // namespace scudo
100