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// Copyright 2020 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 (
"syscall"
"unsafe"
)
// Minimal copy of functionality from x/sys/unix so the cpu package can call
// sysctl without depending on x/sys/unix.
const (
_CTL_QUERY = -2
_SYSCTL_VERS_1 = 0x1000000
)
var _zero uintptr
func sysctl(mib []int32, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (err error) {
var _p0 unsafe.Pointer
if len(mib) > 0 {
_p0 = unsafe.Pointer(&mib[0])
} else {
_p0 = unsafe.Pointer(&_zero)
}
_, _, errno := syscall.Syscall6(
syscall.SYS___SYSCTL,
uintptr(_p0),
uintptr(len(mib)),
uintptr(unsafe.Pointer(old)),
uintptr(unsafe.Pointer(oldlen)),
uintptr(unsafe.Pointer(new)),
uintptr(newlen))
if errno != 0 {
return errno
}
return nil
}
type sysctlNode struct {
Flags uint32
Num int32
Name [32]int8
Ver uint32
__rsvd uint32
Un [16]byte
_sysctl_size [8]byte
_sysctl_func [8]byte
_sysctl_parent [8]byte
_sysctl_desc [8]byte
}
func sysctlNodes(mib []int32) ([]sysctlNode, error) {
var olen uintptr
// Get a list of all sysctl nodes below the given MIB by performing
// a sysctl for the given MIB with CTL_QUERY appended.
mib = append(mib, _CTL_QUERY)
qnode := sysctlNode{Flags: _SYSCTL_VERS_1}
qp := (*byte)(unsafe.Pointer(&qnode))
sz := unsafe.Sizeof(qnode)
if err := sysctl(mib, nil, &olen, qp, sz); err != nil {
return nil, err
}
// Now that we know the size, get the actual nodes.
nodes := make([]sysctlNode, olen/sz)
np := (*byte)(unsafe.Pointer(&nodes[0]))
if err := sysctl(mib, np, &olen, qp, sz); err != nil {
return nil, err
}
return nodes, nil
}
func nametomib(name string) ([]int32, error) {
// Split name into components.
var parts []string
last := 0
for i := 0; i < len(name); i++ {
if name[i] == '.' {
parts = append(parts, name[last:i])
last = i + 1
}
}
parts = append(parts, name[last:])
mib := []int32{}
// Discover the nodes and construct the MIB OID.
for partno, part := range parts {
nodes, err := sysctlNodes(mib)
if err != nil {
return nil, err
}
for _, node := range nodes {
n := make([]byte, 0)
for i := range node.Name {
if node.Name[i] != 0 {
n = append(n, byte(node.Name[i]))
}
}
if string(n) == part {
mib = append(mib, int32(node.Num))
break
}
}
if len(mib) != partno+1 {
return nil, err
}
}
return mib, nil
}
// aarch64SysctlCPUID is struct aarch64_sysctl_cpu_id from NetBSD's <aarch64/armreg.h>
type aarch64SysctlCPUID struct {
midr uint64 /* Main ID Register */
revidr uint64 /* Revision ID Register */
mpidr uint64 /* Multiprocessor Affinity Register */
aa64dfr0 uint64 /* A64 Debug Feature Register 0 */
aa64dfr1 uint64 /* A64 Debug Feature Register 1 */
aa64isar0 uint64 /* A64 Instruction Set Attribute Register 0 */
aa64isar1 uint64 /* A64 Instruction Set Attribute Register 1 */
aa64mmfr0 uint64 /* A64 Memory Model Feature Register 0 */
aa64mmfr1 uint64 /* A64 Memory Model Feature Register 1 */
aa64mmfr2 uint64 /* A64 Memory Model Feature Register 2 */
aa64pfr0 uint64 /* A64 Processor Feature Register 0 */
aa64pfr1 uint64 /* A64 Processor Feature Register 1 */
aa64zfr0 uint64 /* A64 SVE Feature ID Register 0 */
mvfr0 uint32 /* Media and VFP Feature Register 0 */
mvfr1 uint32 /* Media and VFP Feature Register 1 */
mvfr2 uint32 /* Media and VFP Feature Register 2 */
pad uint32
clidr uint64 /* Cache Level ID Register */
ctr uint64 /* Cache Type Register */
}
func sysctlCPUID(name string) (*aarch64SysctlCPUID, error) {
mib, err := nametomib(name)
if err != nil {
return nil, err
}
out := aarch64SysctlCPUID{}
n := unsafe.Sizeof(out)
_, _, errno := syscall.Syscall6(
syscall.SYS___SYSCTL,
uintptr(unsafe.Pointer(&mib[0])),
uintptr(len(mib)),
uintptr(unsafe.Pointer(&out)),
uintptr(unsafe.Pointer(&n)),
uintptr(0),
uintptr(0))
if errno != 0 {
return nil, errno
}
return &out, nil
}
func doinit() {
cpuid, err := sysctlCPUID("machdep.cpu0.cpu_id")
if err != nil {
setMinimalFeatures()
return
}
parseARM64SystemRegisters(cpuid.aa64isar0, cpuid.aa64isar1, cpuid.aa64pfr0)
Initialized = true
}