| // Copyright 2018 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package cpu |
| |
| import ( |
| "strings" |
| "syscall" |
| ) |
| |
| // HWCAP/HWCAP2 bits. These are exposed by Linux. |
| const ( |
| hwcap_FP = 1 << 0 |
| hwcap_ASIMD = 1 << 1 |
| hwcap_EVTSTRM = 1 << 2 |
| hwcap_AES = 1 << 3 |
| hwcap_PMULL = 1 << 4 |
| hwcap_SHA1 = 1 << 5 |
| hwcap_SHA2 = 1 << 6 |
| hwcap_CRC32 = 1 << 7 |
| hwcap_ATOMICS = 1 << 8 |
| hwcap_FPHP = 1 << 9 |
| hwcap_ASIMDHP = 1 << 10 |
| hwcap_CPUID = 1 << 11 |
| hwcap_ASIMDRDM = 1 << 12 |
| hwcap_JSCVT = 1 << 13 |
| hwcap_FCMA = 1 << 14 |
| hwcap_LRCPC = 1 << 15 |
| hwcap_DCPOP = 1 << 16 |
| hwcap_SHA3 = 1 << 17 |
| hwcap_SM3 = 1 << 18 |
| hwcap_SM4 = 1 << 19 |
| hwcap_ASIMDDP = 1 << 20 |
| hwcap_SHA512 = 1 << 21 |
| hwcap_SVE = 1 << 22 |
| hwcap_ASIMDFHM = 1 << 23 |
| ) |
| |
| // linuxKernelCanEmulateCPUID reports whether we're running |
| // on Linux 4.11+. Ideally we'd like to ask the question about |
| // whether the current kernel contains |
| // https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=77c97b4ee21290f5f083173d957843b615abbff2 |
| // but the version number will have to do. |
| func linuxKernelCanEmulateCPUID() bool { |
| var un syscall.Utsname |
| syscall.Uname(&un) |
| var sb strings.Builder |
| for _, b := range un.Release[:] { |
| if b == 0 { |
| break |
| } |
| sb.WriteByte(byte(b)) |
| } |
| major, minor, _, ok := parseRelease(sb.String()) |
| return ok && (major > 4 || major == 4 && minor >= 11) |
| } |
| |
| func doinit() { |
| if err := readHWCAP(); err != nil { |
| // We failed to read /proc/self/auxv. This can happen if the binary has |
| // been given extra capabilities(7) with /bin/setcap. |
| // |
| // When this happens, we have two options. If the Linux kernel is new |
| // enough (4.11+), we can read the arm64 registers directly which'll |
| // trap into the kernel and then return back to userspace. |
| // |
| // But on older kernels, such as Linux 4.4.180 as used on many Synology |
| // devices, calling readARM64Registers (specifically getisar0) will |
| // cause a SIGILL and we'll die. So for older kernels, parse /proc/cpuinfo |
| // instead. |
| // |
| // See golang/go#57336. |
| if linuxKernelCanEmulateCPUID() { |
| readARM64Registers() |
| } else { |
| readLinuxProcCPUInfo() |
| } |
| return |
| } |
| |
| // HWCAP feature bits |
| ARM64.HasFP = isSet(hwCap, hwcap_FP) |
| ARM64.HasASIMD = isSet(hwCap, hwcap_ASIMD) |
| ARM64.HasEVTSTRM = isSet(hwCap, hwcap_EVTSTRM) |
| ARM64.HasAES = isSet(hwCap, hwcap_AES) |
| ARM64.HasPMULL = isSet(hwCap, hwcap_PMULL) |
| ARM64.HasSHA1 = isSet(hwCap, hwcap_SHA1) |
| ARM64.HasSHA2 = isSet(hwCap, hwcap_SHA2) |
| ARM64.HasCRC32 = isSet(hwCap, hwcap_CRC32) |
| ARM64.HasATOMICS = isSet(hwCap, hwcap_ATOMICS) |
| ARM64.HasFPHP = isSet(hwCap, hwcap_FPHP) |
| ARM64.HasASIMDHP = isSet(hwCap, hwcap_ASIMDHP) |
| ARM64.HasCPUID = isSet(hwCap, hwcap_CPUID) |
| ARM64.HasASIMDRDM = isSet(hwCap, hwcap_ASIMDRDM) |
| ARM64.HasJSCVT = isSet(hwCap, hwcap_JSCVT) |
| ARM64.HasFCMA = isSet(hwCap, hwcap_FCMA) |
| ARM64.HasLRCPC = isSet(hwCap, hwcap_LRCPC) |
| ARM64.HasDCPOP = isSet(hwCap, hwcap_DCPOP) |
| ARM64.HasSHA3 = isSet(hwCap, hwcap_SHA3) |
| ARM64.HasSM3 = isSet(hwCap, hwcap_SM3) |
| ARM64.HasSM4 = isSet(hwCap, hwcap_SM4) |
| ARM64.HasASIMDDP = isSet(hwCap, hwcap_ASIMDDP) |
| ARM64.HasSHA512 = isSet(hwCap, hwcap_SHA512) |
| ARM64.HasSVE = isSet(hwCap, hwcap_SVE) |
| ARM64.HasASIMDFHM = isSet(hwCap, hwcap_ASIMDFHM) |
| } |
| |
| func isSet(hwc uint, value uint) bool { |
| return hwc&value != 0 |
| } |
