diff options
Diffstat (limited to 'pkg/cpuid/cpuid_arm64.go')
| -rw-r--r-- | pkg/cpuid/cpuid_arm64.go | 461 |
1 files changed, 461 insertions, 0 deletions
diff --git a/pkg/cpuid/cpuid_arm64.go b/pkg/cpuid/cpuid_arm64.go new file mode 100644 index 000000000..6d71290c9 --- /dev/null +++ b/pkg/cpuid/cpuid_arm64.go @@ -0,0 +1,461 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// +build arm64 + +package cpuid + +import ( + "bytes" + "encoding/binary" + "fmt" + "io/ioutil" + "strconv" + "strings" + + "gvisor.dev/gvisor/pkg/log" +) + +// ARM64 doesn't have a 'cpuid' equivalent, which means it have no architected +// discovery mechanism for hardware features available to userspace code at EL0. +// The kernel exposes the presence of these features to userspace through a set +// of flags(HWCAP/HWCAP2) bits, exposed in the auxilliary vector. +// Ref Documentation/arm64/elf_hwcaps.rst for more info. +// +// Currently, only the HWCAP bits are supported. + +const ( + // Single and double precision float point types. + ARM64FeatureFP Feature = iota + + // Advanced SIMD with single and double precision + // float point arithmetic. + ARM64FeatureASIMD + + // The generic timer is configured to generate + // events at a frequency of approximately 100KHz. + ARM64FeatureEVTSTRM + + // AES instructions(AESE/AESD/AESMC/AESIMC). + ARM64FeatureAES + + // AES instructions(PMULL/PMULL2). + ARM64FeaturePMULL + + // SHA1 instructions(SHA1C/SHA1P/SHA1M etc). + ARM64FeatureSHA1 + + // SHA2 instructions(SHA256H/SHA256H2/SHA256SU0 etc). + ARM64FeatureSHA2 + + // CRC32 instructions(CRC32B/CRC32H/CRC32W etc). + ARM64FeatureCRC32 + + // Atomic instructions(LDADD/LDCLR/LDEOR/LDSET etc). + ARM64FeatureATOMICS + + // Half precision float point arithmetic. + ARM64FeatureFPHP + + // ASIMD with half precision float point arithmetic. + ARM64FeatureASIMDHP + + // EL0 access to certain ID registers is available. + ARM64FeatureCPUID + + // SQRDMLAH and SQRDMLSH instructions implemented. + ARM64FeatureASIMDRDM + + // The FJCVTZS instruction is implemented. + ARM64FeatureJSCVT + + // The FCMLA and FCADD instructions are implemented. + ARM64FeatureFCMA + + // The LDAPRB/LDAPRH/LDAPR instructions are implemented. + ARM64FeatureLRCPC + + // DC instruction(DC CVAP) supported. + ARM64FeatureDCPOP + + // SHA3 instructions(EOR3/RAX1/XAR/BCAX) implemented. + ARM64FeatureSHA3 + + // SM3 instructions(SM3SS1/SM3TT1A/SM3TT1B) implemented. + ARM64FeatureSM3 + + // SM4 instructions(SM4E/SM4EKEY) implemented. + ARM64FeatureSM4 + + // Dot Product instructions(UDOT/SDOT) implemented. + ARM64FeatureASIMDDP + + // SHA2 instructions(SHA512H/SHA512H2/SHA512SU0) implemented. + ARM64FeatureSHA512 + + // Scalable Vector Extension implemented. + ARM64FeatureSVE + + // FMLAL and FMLSL instructions are implemented. + ARM64FeatureASIMDFHM +) + +// ELF auxiliary vector tags +const ( + _AT_NULL = 0 // End of vector + _AT_HWCAP = 16 // hardware capability bit vector + _AT_HWCAP2 = 26 // hardware capability bit vector 2 +) + +// These should not be changed after they are initialized. +var hwCap uint + +// To make emulation of /proc/cpuinfo easy, these names match the names of the +// basic features in Linux defined in arch/arm64/kernel/cpuinfo.c. +var arm64FeatureStrings = map[Feature]string{ + ARM64FeatureFP: "fp", + ARM64FeatureASIMD: "asimd", + ARM64FeatureEVTSTRM: "evtstrm", + ARM64FeatureAES: "aes", + ARM64FeaturePMULL: "pmull", + ARM64FeatureSHA1: "sha1", + ARM64FeatureSHA2: "sha2", + ARM64FeatureCRC32: "crc32", + ARM64FeatureATOMICS: "atomics", + ARM64FeatureFPHP: "fphp", + ARM64FeatureASIMDHP: "asimdhp", + ARM64FeatureCPUID: "cpuid", + ARM64FeatureASIMDRDM: "asimdrdm", + ARM64FeatureJSCVT: "jscvt", + ARM64FeatureFCMA: "fcma", + ARM64FeatureLRCPC: "lrcpc", + ARM64FeatureDCPOP: "dcpop", + ARM64FeatureSHA3: "sha3", + ARM64FeatureSM3: "sm3", + ARM64FeatureSM4: "sm4", + ARM64FeatureASIMDDP: "asimddp", + ARM64FeatureSHA512: "sha512", + ARM64FeatureSVE: "sve", + ARM64FeatureASIMDFHM: "asimdfhm", +} + +var ( + cpuFreqMHz float64 + cpuImplHex uint64 + cpuArchDec uint64 + cpuVarHex uint64 + cpuPartHex uint64 + cpuRevDec uint64 +) + +// arm64FeaturesFromString includes features from arm64FeatureStrings. +var arm64FeaturesFromString = make(map[string]Feature) + +// FeatureFromString returns the Feature associated with the given feature +// string plus a bool to indicate if it could find the feature. +func FeatureFromString(s string) (Feature, bool) { + f, b := arm64FeaturesFromString[s] + return f, b +} + +// String implements fmt.Stringer. +func (f Feature) String() string { + if s := f.flagString(); s != "" { + return s + } + + return fmt.Sprintf("<cpuflag %d>", f) +} + +func (f Feature) flagString() string { + if s, ok := arm64FeatureStrings[f]; ok { + return s + } + + return "" +} + +// FeatureSet is a set of Features for a CPU. +// +// +stateify savable +type FeatureSet struct { + // Set is the set of features that are enabled in this FeatureSet. + Set map[Feature]bool + + // CPUImplementer is part of the processor signature. + CPUImplementer uint8 + + // CPUArchitecture is part of the processor signature. + CPUArchitecture uint8 + + // CPUVariant is part of the processor signature. + CPUVariant uint8 + + // CPUPartnum is part of the processor signature. + CPUPartnum uint16 + + // CPURevision is part of the processor signature. + CPURevision uint8 +} + +// CheckHostCompatible returns nil if fs is a subset of the host feature set. +// Noop on arm64. +func (fs *FeatureSet) CheckHostCompatible() error { + return nil +} + +// ExtendedStateSize returns the number of bytes needed to save the "extended +// state" for this processor and the boundary it must be aligned to. Extended +// state includes floating point(NEON) registers, and other cpu state that's not +// associated with the normal task context. +func (fs *FeatureSet) ExtendedStateSize() (size, align uint) { + // ARMv8 provide 32x128bits NEON registers. + // + // Ref arch/arm64/include/uapi/asm/ptrace.h + // struct user_fpsimd_state { + // __uint128_t vregs[32]; + // __u32 fpsr; + // __u32 fpcr; + // __u32 __reserved[2]; + // }; + return 528, 16 +} + +// HasFeature tests whether or not a feature is in the given feature set. +func (fs *FeatureSet) HasFeature(feature Feature) bool { + return fs.Set[feature] +} + +// UseXsaveopt returns true if 'fs' supports the "xsaveopt" instruction. +// Noop on arm64. +func (fs *FeatureSet) UseXsave() bool { + return false +} + +// FlagsString prints out supported CPU "flags" field in /proc/cpuinfo. +func (fs *FeatureSet) FlagsString() string { + var s []string + for f, _ := range arm64FeatureStrings { + if fs.Set[f] { + if fstr := f.flagString(); fstr != "" { + s = append(s, fstr) + } + } + } + return strings.Join(s, " ") +} + +// WriteCPUInfoTo is to generate a section of one cpu in /proc/cpuinfo. This is +// a minimal /proc/cpuinfo, and the bogomips field is simply made up. +func (fs FeatureSet) WriteCPUInfoTo(cpu uint, b *bytes.Buffer) { + fmt.Fprintf(b, "processor\t: %d\n", cpu) + fmt.Fprintf(b, "BogoMIPS\t: %.02f\n", cpuFreqMHz) // It's bogus anyway. + fmt.Fprintf(b, "Features\t\t: %s\n", fs.FlagsString()) + fmt.Fprintf(b, "CPU implementer\t: 0x%x\n", cpuImplHex) + fmt.Fprintf(b, "CPU architecture\t: %d\n", cpuArchDec) + fmt.Fprintf(b, "CPU variant\t: 0x%x\n", cpuVarHex) + fmt.Fprintf(b, "CPU part\t: 0x%x\n", cpuPartHex) + fmt.Fprintf(b, "CPU revision\t: %d\n", cpuRevDec) + fmt.Fprintln(b, "") // The /proc/cpuinfo file ends with an extra newline. +} + +// HostFeatureSet uses hwCap to get host values and construct a feature set +// that matches that of the host machine. +func HostFeatureSet() *FeatureSet { + s := make(map[Feature]bool) + + for f, _ := range arm64FeatureStrings { + if hwCap&(1<<f) != 0 { + s[f] = true + } + } + + return &FeatureSet{ + Set: s, + CPUImplementer: uint8(cpuImplHex), + CPUArchitecture: uint8(cpuArchDec), + CPUVariant: uint8(cpuVarHex), + CPUPartnum: uint16(cpuPartHex), + CPURevision: uint8(cpuRevDec), + } +} + +// Reads bogomips from host /proc/cpuinfo. Must run before whitelisting. +// This value is used to create the fake /proc/cpuinfo from a FeatureSet. +func initCPUInfo() { + cpuinfob, err := ioutil.ReadFile("/proc/cpuinfo") + if err != nil { + // Leave it as 0. The standalone VDSO bails out in the same way. + log.Warningf("Could not read /proc/cpuinfo: %v", err) + return + } + cpuinfo := string(cpuinfob) + + // We get the value straight from host /proc/cpuinfo. + for _, line := range strings.Split(cpuinfo, "\n") { + switch { + case strings.Contains(line, "BogoMIPS"): + { + splitMHz := strings.Split(line, ":") + if len(splitMHz) < 2 { + log.Warningf("Could not read /proc/cpuinfo: malformed BogoMIPS") + break + } + + // If there was a problem, leave cpuFreqMHz as 0. + var err error + cpuFreqMHz, err = strconv.ParseFloat(strings.TrimSpace(splitMHz[1]), 64) + if err != nil { + log.Warningf("Could not parse BogoMIPS value %v: %v", splitMHz[1], err) + cpuFreqMHz = 0 + } + } + case strings.Contains(line, "CPU implementer"): + { + splitImpl := strings.Split(line, ":") + if len(splitImpl) < 2 { + log.Warningf("Could not read /proc/cpuinfo: malformed CPU implementer") + break + } + + // If there was a problem, leave cpuImplHex as 0. + var err error + cpuImplHex, err = strconv.ParseUint(strings.TrimSpace(splitImpl[1]), 0, 64) + if err != nil { + log.Warningf("Could not parse CPU implementer value %v: %v", splitImpl[1], err) + cpuImplHex = 0 + } + } + case strings.Contains(line, "CPU architecture"): + { + splitArch := strings.Split(line, ":") + if len(splitArch) < 2 { + log.Warningf("Could not read /proc/cpuinfo: malformed CPU architecture") + break + } + + // If there was a problem, leave cpuArchDec as 0. + var err error + cpuArchDec, err = strconv.ParseUint(strings.TrimSpace(splitArch[1]), 0, 64) + if err != nil { + log.Warningf("Could not parse CPU architecture value %v: %v", splitArch[1], err) + cpuArchDec = 0 + } + } + case strings.Contains(line, "CPU variant"): + { + splitVar := strings.Split(line, ":") + if len(splitVar) < 2 { + log.Warningf("Could not read /proc/cpuinfo: malformed CPU variant") + break + } + + // If there was a problem, leave cpuVarHex as 0. + var err error + cpuVarHex, err = strconv.ParseUint(strings.TrimSpace(splitVar[1]), 0, 64) + if err != nil { + log.Warningf("Could not parse CPU variant value %v: %v", splitVar[1], err) + cpuVarHex = 0 + } + } + case strings.Contains(line, "CPU part"): + { + splitPart := strings.Split(line, ":") + if len(splitPart) < 2 { + log.Warningf("Could not read /proc/cpuinfo: malformed CPU part") + break + } + + // If there was a problem, leave cpuPartHex as 0. + var err error + cpuPartHex, err = strconv.ParseUint(strings.TrimSpace(splitPart[1]), 0, 64) + if err != nil { + log.Warningf("Could not parse CPU part value %v: %v", splitPart[1], err) + cpuPartHex = 0 + } + } + case strings.Contains(line, "CPU revision"): + { + splitRev := strings.Split(line, ":") + if len(splitRev) < 2 { + log.Warningf("Could not read /proc/cpuinfo: malformed CPU revision") + break + } + + // If there was a problem, leave cpuRevDec as 0. + var err error + cpuRevDec, err = strconv.ParseUint(strings.TrimSpace(splitRev[1]), 0, 64) + if err != nil { + log.Warningf("Could not parse CPU revision value %v: %v", splitRev[1], err) + cpuRevDec = 0 + } + } + } + } +} + +// The auxiliary vector of a process on the Linux system can be read +// from /proc/self/auxv, and tags and values are stored as 8-bytes +// decimal key-value pairs on the 64-bit system. +// +// $ od -t d8 /proc/self/auxv +// 0000000 33 140734615224320 +// 0000020 16 3219913727 +// 0000040 6 4096 +// 0000060 17 100 +// 0000100 3 94665627353152 +// 0000120 4 56 +// 0000140 5 9 +// 0000160 7 140425502162944 +// 0000200 8 0 +// 0000220 9 94665627365760 +// 0000240 11 1000 +// 0000260 12 1000 +// 0000300 13 1000 +// 0000320 14 1000 +// 0000340 23 0 +// 0000360 25 140734614619513 +// 0000400 26 0 +// 0000420 31 140734614626284 +// 0000440 15 140734614619529 +// 0000460 0 0 +func initHwCap() { + auxv, err := ioutil.ReadFile("/proc/self/auxv") + if err != nil { + log.Warningf("Could not read /proc/self/auxv: %v", err) + return + } + + l := len(auxv) / 16 + for i := 0; i < l; i++ { + tag := binary.LittleEndian.Uint64(auxv[i*16:]) + val := binary.LittleEndian.Uint64(auxv[(i*16 + 8):]) + if tag == _AT_HWCAP { + hwCap = uint(val) + break + } + } +} + +func initFeaturesFromString() { + for f, s := range arm64FeatureStrings { + arm64FeaturesFromString[s] = f + } +} + +func init() { + initCPUInfo() + initHwCap() + initFeaturesFromString() +} |