src/runtime/os_freebsd.go - go - Git at Google

 // Copyright 2011 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 runtime

 import (
 	"internal/abi"
 	"internal/goarch"
 	"unsafe"
 )

 type mOS struct{}

 //go:noescape
 func thr_new(param *thrparam, size int32) int32

 //go:noescape
 func sigaltstack(new, old *stackt)

 //go:noescape
 func sigprocmask(how int32, new, old *sigset)

 //go:noescape
 func setitimer(mode int32, new, old *itimerval)

 //go:noescape
 func sysctl(mib *uint32, miblen uint32, out *byte, size *uintptr, dst *byte, ndst uintptr) int32

 func raiseproc(sig uint32)

 func thr_self() thread
 func thr_kill(tid thread, sig int)

 //go:noescape
 func sys_umtx_op(addr *uint32, mode int32, val uint32, uaddr1 uintptr, ut *umtx_time) int32

 func osyield()

 //go:nosplit
 func osyield_no_g() {
 	osyield()
 }

 func kqueue() int32

 //go:noescape
 func kevent(kq int32, ch *keventt, nch int32, ev *keventt, nev int32, ts *timespec) int32

 func pipe2(flags int32) (r, w int32, errno int32)
 func closeonexec(fd int32)

 // From FreeBSD's <sys/sysctl.h>
 const (
 	_CTL_HW      = 6
 	_HW_PAGESIZE = 7
 )

 var sigset_all = sigset{[4]uint32{^uint32(0), ^uint32(0), ^uint32(0), ^uint32(0)}}

 // Undocumented numbers from FreeBSD's lib/libc/gen/sysctlnametomib.c.
 const (
 	_CTL_QUERY     = 0
 	_CTL_QUERY_MIB = 3
 )

 // sysctlnametomib fill mib with dynamically assigned sysctl entries of name,
 // return count of effected mib slots, return 0 on error.
 func sysctlnametomib(name []byte, mib *[_CTL_MAXNAME]uint32) uint32 {
 	oid := [2]uint32{_CTL_QUERY, _CTL_QUERY_MIB}
 	miblen := uintptr(_CTL_MAXNAME)
 	if sysctl(&oid[0], 2, (*byte)(unsafe.Pointer(mib)), &miblen, (*byte)(unsafe.Pointer(&name[0])), (uintptr)(len(name))) < 0 {
 		return 0
 	}
 	miblen /= unsafe.Sizeof(uint32(0))
 	if miblen <= 0 {
 		return 0
 	}
 	return uint32(miblen)
 }

 const (
 	_CPU_CURRENT_PID = -1 // Current process ID.
 )

 //go:noescape
 func cpuset_getaffinity(level int, which int, id int64, size int, mask *byte) int32

 //go:systemstack
 func getncpu() int32 {
 	// Use a large buffer for the CPU mask. We're on the system
 	// stack, so this is fine, and we can't allocate memory for a
 	// dynamically-sized buffer at this point.
 	const maxCPUs = 64 * 1024
 	var mask [maxCPUs / 8]byte
 	var mib [_CTL_MAXNAME]uint32

 	// According to FreeBSD's /usr/src/sys/kern/kern_cpuset.c,
 	// cpuset_getaffinity return ERANGE when provided buffer size exceed the limits in kernel.
 	// Querying kern.smp.maxcpus to calculate maximum buffer size.
 	// See https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=200802

 	// Variable kern.smp.maxcpus introduced at Dec 23 2003, revision 123766,
 	// with dynamically assigned sysctl entries.
 	miblen := sysctlnametomib([]byte("kern.smp.maxcpus"), &mib)
 	if miblen == 0 {
 		return 1
 	}

 	// Query kern.smp.maxcpus.
 	dstsize := uintptr(4)
 	maxcpus := uint32(0)
 	if sysctl(&mib[0], miblen, (*byte)(unsafe.Pointer(&maxcpus)), &dstsize, nil, 0) != 0 {
 		return 1
 	}

 	maskSize := int(maxcpus+7) / 8
 	if maskSize < goarch.PtrSize {
 		maskSize = goarch.PtrSize
 	}
 	if maskSize > len(mask) {
 		maskSize = len(mask)
 	}

 	if cpuset_getaffinity(_CPU_LEVEL_WHICH, _CPU_WHICH_PID, _CPU_CURRENT_PID,
 		maskSize, (*byte)(unsafe.Pointer(&mask[0]))) != 0 {
 		return 1
 	}
 	n := int32(0)
 	for _, v := range mask[:maskSize] {
 		for v != 0 {
 			n += int32(v & 1)
 			v >>= 1
 		}
 	}
 	if n == 0 {
 		return 1
 	}
 	return n
 }

 func getPageSize() uintptr {
 	mib := [2]uint32{_CTL_HW, _HW_PAGESIZE}
 	out := uint32(0)
 	nout := unsafe.Sizeof(out)
 	ret := sysctl(&mib[0], 2, (*byte)(unsafe.Pointer(&out)), &nout, nil, 0)
 	if ret >= 0 {
 		return uintptr(out)
 	}
 	return 0
 }

 // FreeBSD's umtx_op syscall is effectively the same as Linux's futex, and
 // thus the code is largely similar. See Linux implementation
 // and lock_futex.go for comments.

 //go:nosplit
 func futexsleep(addr *uint32, val uint32, ns int64) {
 	systemstack(func() {
 		futexsleep1(addr, val, ns)
 	})
 }

 func futexsleep1(addr *uint32, val uint32, ns int64) {
 	var utp *umtx_time
 	if ns >= 0 {
 		var ut umtx_time
 		ut._clockid = _CLOCK_MONOTONIC
 		ut._timeout.setNsec(ns)
 		utp = &ut
 	}
 	ret := sys_umtx_op(addr, _UMTX_OP_WAIT_UINT_PRIVATE, val, unsafe.Sizeof(*utp), utp)
 	if ret >= 0 || ret == -_EINTR || ret == -_ETIMEDOUT {
 		return
 	}
 	print("umtx_wait addr=", addr, " val=", val, " ret=", ret, "\n")
 	*(*int32)(unsafe.Pointer(uintptr(0x1005))) = 0x1005
 }

 //go:nosplit
 func futexwakeup(addr *uint32, cnt uint32) {
 	ret := sys_umtx_op(addr, _UMTX_OP_WAKE_PRIVATE, cnt, 0, nil)
 	if ret >= 0 {
 		return
 	}

 	systemstack(func() {
 		print("umtx_wake_addr=", addr, " ret=", ret, "\n")
 	})
 }

 func thr_start()

 // May run with m.p==nil, so write barriers are not allowed.
 //
 //go:nowritebarrier
 func newosproc(mp *m) {
 	stk := unsafe.Pointer(mp.g0.stack.hi)
 	if false {
 		print("newosproc stk=", stk, " m=", mp, " g=", mp.g0, " thr_start=", abi.FuncPCABI0(thr_start), " id=", mp.id, " ostk=", &mp, "\n")
 	}

 	param := thrparam{
 		start_func: abi.FuncPCABI0(thr_start),
 		arg:        unsafe.Pointer(mp),
 		stack_base: mp.g0.stack.lo,
 		stack_size: uintptr(stk) - mp.g0.stack.lo,
 		child_tid:  nil, // minit will record tid
 		parent_tid: nil,
 		tls_base:   unsafe.Pointer(&mp.tls[0]),
 		tls_size:   unsafe.Sizeof(mp.tls),
 	}

 	var oset sigset
 	sigprocmask(_SIG_SETMASK, &sigset_all, &oset)
 	ret := retryOnEAGAIN(func() int32 {
 		errno := thr_new(&param, int32(unsafe.Sizeof(param)))
 		// thr_new returns negative errno
 		return -errno
 	})
 	sigprocmask(_SIG_SETMASK, &oset, nil)
 	if ret != 0 {
 		print("runtime: failed to create new OS thread (have ", mcount(), " already; errno=", ret, ")\n")
 		throw("newosproc")
 	}
 }

 // Version of newosproc that doesn't require a valid G.
 //
 //go:nosplit
 func newosproc0(stacksize uintptr, fn unsafe.Pointer) {
 	stack := sysAlloc(stacksize, &memstats.stacks_sys)
 	if stack == nil {
 		writeErrStr(failallocatestack)
 		exit(1)
 	}
 	// This code "knows" it's being called once from the library
 	// initialization code, and so it's using the static m0 for the
 	// tls and procid (thread) pointers. thr_new() requires the tls
 	// pointers, though the tid pointers can be nil.
 	// However, newosproc0 is currently unreachable because builds
 	// utilizing c-shared/c-archive force external linking.
 	param := thrparam{
 		start_func: uintptr(fn),
 		arg:        nil,
 		stack_base: uintptr(stack), //+stacksize?
 		stack_size: stacksize,
 		child_tid:  nil, // minit will record tid
 		parent_tid: nil,
 		tls_base:   unsafe.Pointer(&m0.tls[0]),
 		tls_size:   unsafe.Sizeof(m0.tls),
 	}

 	var oset sigset
 	sigprocmask(_SIG_SETMASK, &sigset_all, &oset)
 	ret := thr_new(&param, int32(unsafe.Sizeof(param)))
 	sigprocmask(_SIG_SETMASK, &oset, nil)
 	if ret < 0 {
 		writeErrStr(failthreadcreate)
 		exit(1)
 	}
 }

 // Called to do synchronous initialization of Go code built with
 // -buildmode=c-archive or -buildmode=c-shared.
 // None of the Go runtime is initialized.
 //
 //go:nosplit
 //go:nowritebarrierrec
 func libpreinit() {
 	initsig(true)
 }

 func osinit() {
 	ncpu = getncpu()
 	if physPageSize == 0 {
 		physPageSize = getPageSize()
 	}
 }

 var urandom_dev = []byte("/dev/urandom\x00")

 //go:nosplit
 func getRandomData(r []byte) {
 	fd := open(&urandom_dev[0], 0 /* O_RDONLY */, 0)
 	n := read(fd, unsafe.Pointer(&r[0]), int32(len(r)))
 	closefd(fd)
 	extendRandom(r, int(n))
 }

 func goenvs() {
 	goenvs_unix()
 }

 // Called to initialize a new m (including the bootstrap m).
 // Called on the parent thread (main thread in case of bootstrap), can allocate memory.
 func mpreinit(mp *m) {
 	mp.gsignal = malg(32 * 1024)
 	mp.gsignal.m = mp
 }

 // Called to initialize a new m (including the bootstrap m).
 // Called on the new thread, cannot allocate memory.
 func minit() {
 	getg().m.procid = uint64(thr_self())

 	// On FreeBSD before about April 2017 there was a bug such
 	// that calling execve from a thread other than the main
 	// thread did not reset the signal stack. That would confuse
 	// minitSignals, which calls minitSignalStack, which checks
 	// whether there is currently a signal stack and uses it if
 	// present. To avoid this confusion, explicitly disable the
 	// signal stack on the main thread when not running in a
 	// library. This can be removed when we are confident that all
 	// FreeBSD users are running a patched kernel. See issue #15658.
 	if gp := getg(); !isarchive && !islibrary && gp.m == &m0 && gp == gp.m.g0 {
 		st := stackt{ss_flags: _SS_DISABLE}
 		sigaltstack(&st, nil)
 	}

 	minitSignals()
 }

 // Called from dropm to undo the effect of an minit.
 //
 //go:nosplit
 func unminit() {
 	unminitSignals()
 }

 // Called from exitm, but not from drop, to undo the effect of thread-owned
 // resources in minit, semacreate, or elsewhere. Do not take locks after calling this.
 func mdestroy(mp *m) {
 }

 func sigtramp()

 type sigactiont struct {
 	sa_handler uintptr
 	sa_flags   int32
 	sa_mask    sigset
 }

 // See os_freebsd2.go, os_freebsd_amd64.go for setsig function

 //go:nosplit
 //go:nowritebarrierrec
 func setsigstack(i uint32) {
 	var sa sigactiont
 	sigaction(i, nil, &sa)
 	if sa.sa_flags&_SA_ONSTACK != 0 {
 		return
 	}
 	sa.sa_flags |= _SA_ONSTACK
 	sigaction(i, &sa, nil)
 }

 //go:nosplit
 //go:nowritebarrierrec
 func getsig(i uint32) uintptr {
 	var sa sigactiont
 	sigaction(i, nil, &sa)
 	return sa.sa_handler
 }

 // setSignalstackSP sets the ss_sp field of a stackt.
 //
 //go:nosplit
 func setSignalstackSP(s *stackt, sp uintptr) {
 	s.ss_sp = sp
 }

 //go:nosplit
 //go:nowritebarrierrec
 func sigaddset(mask *sigset, i int) {
 	mask.__bits[(i-1)/32] |= 1 << ((uint32(i) - 1) & 31)
 }

 func sigdelset(mask *sigset, i int) {
 	mask.__bits[(i-1)/32] &^= 1 << ((uint32(i) - 1) & 31)
 }

 //go:nosplit
 func (c *sigctxt) fixsigcode(sig uint32) {
 }

 func setProcessCPUProfiler(hz int32) {
 	setProcessCPUProfilerTimer(hz)
 }

 func setThreadCPUProfiler(hz int32) {
 	setThreadCPUProfilerHz(hz)
 }

 //go:nosplit
 func validSIGPROF(mp *m, c *sigctxt) bool {
 	return true
 }

 func sysargs(argc int32, argv **byte) {
 	n := argc + 1

 	// skip over argv, envp to get to auxv
 	for argv_index(argv, n) != nil {
 		n++
 	}

 	// skip NULL separator
 	n++

 	// now argv+n is auxv
 	auxv := (*[1 << 28]uintptr)(add(unsafe.Pointer(argv), uintptr(n)*goarch.PtrSize))
 	sysauxv(auxv[:])
 }

 const (
 	_AT_NULL     = 0  // Terminates the vector
 	_AT_PAGESZ   = 6  // Page size in bytes
 	_AT_TIMEKEEP = 22 // Pointer to timehands.
 	_AT_HWCAP    = 25 // CPU feature flags
 	_AT_HWCAP2   = 26 // CPU feature flags 2
 )

 func sysauxv(auxv []uintptr) {
 	for i := 0; auxv[i] != _AT_NULL; i += 2 {
 		tag, val := auxv[i], auxv[i+1]
 		switch tag {
 		// _AT_NCPUS from auxv shouldn't be used due to golang.org/issue/15206
 		case _AT_PAGESZ:
 			physPageSize = val
 		case _AT_TIMEKEEP:
 			timekeepSharedPage = (*vdsoTimekeep)(unsafe.Pointer(val))
 		}

 		archauxv(tag, val)
 	}
 }

 // sysSigaction calls the sigaction system call.
 //
 //go:nosplit
 func sysSigaction(sig uint32, new, old *sigactiont) {
 	// Use system stack to avoid split stack overflow on amd64
 	if asmSigaction(uintptr(sig), new, old) != 0 {
 		systemstack(func() {
 			throw("sigaction failed")
 		})
 	}
 }

 // asmSigaction is implemented in assembly.
 //
 //go:noescape
 func asmSigaction(sig uintptr, new, old *sigactiont) int32

 // raise sends a signal to the calling thread.
 //
 // It must be nosplit because it is used by the signal handler before
 // it definitely has a Go stack.
 //
 //go:nosplit
 func raise(sig uint32) {
 	thr_kill(thr_self(), int(sig))
 }

 func signalM(mp *m, sig int) {
 	thr_kill(thread(mp.procid), sig)
 }

 // sigPerThreadSyscall is only used on linux, so we assign a bogus signal
 // number.
 const sigPerThreadSyscall = 1 << 31

 //go:nosplit
 func runPerThreadSyscall() {
 	throw("runPerThreadSyscall only valid on linux")
 }
	// Copyright 2011 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 runtime

	import (
	"internal/abi"
	"internal/goarch"
	"unsafe"
	)

	type mOS struct{}

	//go:noescape
	func thr_new(param *thrparam, size int32) int32

	//go:noescape
	func sigaltstack(new, old *stackt)

	//go:noescape
	func sigprocmask(how int32, new, old *sigset)

	//go:noescape
	func setitimer(mode int32, new, old *itimerval)

	//go:noescape
	func sysctl(mib uint32, miblen uint32, out byte, size uintptr, dst byte, ndst uintptr) int32

	func raiseproc(sig uint32)

	func thr_self() thread
	func thr_kill(tid thread, sig int)

	//go:noescape
	func sys_umtx_op(addr uint32, mode int32, val uint32, uaddr1 uintptr, ut umtx_time) int32

	func osyield()

	//go:nosplit
	func osyield_no_g() {
	osyield()
	}

	func kqueue() int32

	//go:noescape
	func kevent(kq int32, ch keventt, nch int32, ev keventt, nev int32, ts *timespec) int32

	func pipe2(flags int32) (r, w int32, errno int32)
	func closeonexec(fd int32)

	// From FreeBSD's <sys/sysctl.h>
	const (
	_CTL_HW = 6
	_HW_PAGESIZE = 7
	)

	var sigset_all = sigset{[4]uint32{^uint32(0), ^uint32(0), ^uint32(0), ^uint32(0)}}

	// Undocumented numbers from FreeBSD's lib/libc/gen/sysctlnametomib.c.
	const (
	_CTL_QUERY = 0
	_CTL_QUERY_MIB = 3
	)

	// sysctlnametomib fill mib with dynamically assigned sysctl entries of name,
	// return count of effected mib slots, return 0 on error.
	func sysctlnametomib(name []byte, mib *[_CTL_MAXNAME]uint32) uint32 {
	oid := [2]uint32{_CTL_QUERY, _CTL_QUERY_MIB}
	miblen := uintptr(_CTL_MAXNAME)
	if sysctl(&oid[0], 2, (byte)(unsafe.Pointer(mib)), &miblen, (byte)(unsafe.Pointer(&name[0])), (uintptr)(len(name))) < 0 {
	return 0
	}
	miblen /= unsafe.Sizeof(uint32(0))
	if miblen <= 0 {
	return 0
	}
	return uint32(miblen)
	}

	const (
	_CPU_CURRENT_PID = -1 // Current process ID.
	)

	//go:noescape
	func cpuset_getaffinity(level int, which int, id int64, size int, mask *byte) int32

	//go:systemstack
	func getncpu() int32 {
	// Use a large buffer for the CPU mask. We're on the system
	// stack, so this is fine, and we can't allocate memory for a
	// dynamically-sized buffer at this point.
	const maxCPUs = 64 * 1024
	var mask [maxCPUs / 8]byte
	var mib [_CTL_MAXNAME]uint32

	// According to FreeBSD's /usr/src/sys/kern/kern_cpuset.c,
	// cpuset_getaffinity return ERANGE when provided buffer size exceed the limits in kernel.
	// Querying kern.smp.maxcpus to calculate maximum buffer size.
	// See https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=200802

	// Variable kern.smp.maxcpus introduced at Dec 23 2003, revision 123766,
	// with dynamically assigned sysctl entries.
	miblen := sysctlnametomib([]byte("kern.smp.maxcpus"), &mib)
	if miblen == 0 {
	return 1
	}

	// Query kern.smp.maxcpus.
	dstsize := uintptr(4)
	maxcpus := uint32(0)
	if sysctl(&mib[0], miblen, (*byte)(unsafe.Pointer(&maxcpus)), &dstsize, nil, 0) != 0 {
	return 1
	}

	maskSize := int(maxcpus+7) / 8
	if maskSize < goarch.PtrSize {
	maskSize = goarch.PtrSize
	}
	if maskSize > len(mask) {
	maskSize = len(mask)
	}

	if cpuset_getaffinity(_CPU_LEVEL_WHICH, _CPU_WHICH_PID, _CPU_CURRENT_PID,
	maskSize, (*byte)(unsafe.Pointer(&mask[0]))) != 0 {
	return 1
	}
	n := int32(0)
	for _, v := range mask[:maskSize] {
	for v != 0 {
	n += int32(v & 1)
	v >>= 1
	}
	}
	if n == 0 {
	return 1
	}
	return n
	}

	func getPageSize() uintptr {
	mib := [2]uint32{_CTL_HW, _HW_PAGESIZE}
	out := uint32(0)
	nout := unsafe.Sizeof(out)
	ret := sysctl(&mib[0], 2, (*byte)(unsafe.Pointer(&out)), &nout, nil, 0)
	if ret >= 0 {
	return uintptr(out)
	}
	return 0
	}

	// FreeBSD's umtx_op syscall is effectively the same as Linux's futex, and
	// thus the code is largely similar. See Linux implementation
	// and lock_futex.go for comments.

	//go:nosplit
	func futexsleep(addr *uint32, val uint32, ns int64) {
	systemstack(func() {
	futexsleep1(addr, val, ns)
	})
	}

	func futexsleep1(addr *uint32, val uint32, ns int64) {
	var utp *umtx_time
	if ns >= 0 {
	var ut umtx_time
	ut._clockid = _CLOCK_MONOTONIC
	ut._timeout.setNsec(ns)
	utp = &ut
	}
	ret := sys_umtx_op(addr, _UMTX_OP_WAIT_UINT_PRIVATE, val, unsafe.Sizeof(*utp), utp)
	if ret >= 0 \|\| ret == -_EINTR \|\| ret == -_ETIMEDOUT {
	return
	}
	print("umtx_wait addr=", addr, " val=", val, " ret=", ret, "\n")
	(int32)(unsafe.Pointer(uintptr(0x1005))) = 0x1005
	}

	//go:nosplit
	func futexwakeup(addr *uint32, cnt uint32) {
	ret := sys_umtx_op(addr, _UMTX_OP_WAKE_PRIVATE, cnt, 0, nil)
	if ret >= 0 {
	return
	}

	systemstack(func() {
	print("umtx_wake_addr=", addr, " ret=", ret, "\n")
	})
	}

	func thr_start()

	// May run with m.p==nil, so write barriers are not allowed.
	//
	//go:nowritebarrier
	func newosproc(mp *m) {
	stk := unsafe.Pointer(mp.g0.stack.hi)
	if false {
	print("newosproc stk=", stk, " m=", mp, " g=", mp.g0, " thr_start=", abi.FuncPCABI0(thr_start), " id=", mp.id, " ostk=", &mp, "\n")
	}

	param := thrparam{
	start_func: abi.FuncPCABI0(thr_start),
	arg: unsafe.Pointer(mp),
	stack_base: mp.g0.stack.lo,
	stack_size: uintptr(stk) - mp.g0.stack.lo,
	child_tid: nil, // minit will record tid
	parent_tid: nil,
	tls_base: unsafe.Pointer(&mp.tls[0]),
	tls_size: unsafe.Sizeof(mp.tls),
	}

	var oset sigset
	sigprocmask(_SIG_SETMASK, &sigset_all, &oset)
	ret := retryOnEAGAIN(func() int32 {
	errno := thr_new(&param, int32(unsafe.Sizeof(param)))
	// thr_new returns negative errno
	return -errno
	})
	sigprocmask(_SIG_SETMASK, &oset, nil)
	if ret != 0 {
	print("runtime: failed to create new OS thread (have ", mcount(), " already; errno=", ret, ")\n")
	throw("newosproc")
	}
	}

	// Version of newosproc that doesn't require a valid G.
	//
	//go:nosplit
	func newosproc0(stacksize uintptr, fn unsafe.Pointer) {
	stack := sysAlloc(stacksize, &memstats.stacks_sys)
	if stack == nil {
	writeErrStr(failallocatestack)
	exit(1)
	}
	// This code "knows" it's being called once from the library
	// initialization code, and so it's using the static m0 for the
	// tls and procid (thread) pointers. thr_new() requires the tls
	// pointers, though the tid pointers can be nil.
	// However, newosproc0 is currently unreachable because builds
	// utilizing c-shared/c-archive force external linking.
	param := thrparam{
	start_func: uintptr(fn),
	arg: nil,
	stack_base: uintptr(stack), //+stacksize?
	stack_size: stacksize,
	child_tid: nil, // minit will record tid
	parent_tid: nil,
	tls_base: unsafe.Pointer(&m0.tls[0]),
	tls_size: unsafe.Sizeof(m0.tls),
	}

	var oset sigset
	sigprocmask(_SIG_SETMASK, &sigset_all, &oset)
	ret := thr_new(&param, int32(unsafe.Sizeof(param)))
	sigprocmask(_SIG_SETMASK, &oset, nil)
	if ret < 0 {
	writeErrStr(failthreadcreate)
	exit(1)
	}
	}

	// Called to do synchronous initialization of Go code built with
	// -buildmode=c-archive or -buildmode=c-shared.
	// None of the Go runtime is initialized.
	//
	//go:nosplit
	//go:nowritebarrierrec
	func libpreinit() {
	initsig(true)
	}

	func osinit() {
	ncpu = getncpu()
	if physPageSize == 0 {
	physPageSize = getPageSize()
	}
	}

	var urandom_dev = []byte("/dev/urandom\x00")

	//go:nosplit
	func getRandomData(r []byte) {
	fd := open(&urandom_dev[0], 0 /* O_RDONLY */, 0)
	n := read(fd, unsafe.Pointer(&r[0]), int32(len(r)))
	closefd(fd)
	extendRandom(r, int(n))
	}

	func goenvs() {
	goenvs_unix()
	}

	// Called to initialize a new m (including the bootstrap m).
	// Called on the parent thread (main thread in case of bootstrap), can allocate memory.
	func mpreinit(mp *m) {
	mp.gsignal = malg(32 * 1024)
	mp.gsignal.m = mp
	}

	// Called to initialize a new m (including the bootstrap m).
	// Called on the new thread, cannot allocate memory.
	func minit() {
	getg().m.procid = uint64(thr_self())

	// On FreeBSD before about April 2017 there was a bug such
	// that calling execve from a thread other than the main
	// thread did not reset the signal stack. That would confuse
	// minitSignals, which calls minitSignalStack, which checks
	// whether there is currently a signal stack and uses it if
	// present. To avoid this confusion, explicitly disable the
	// signal stack on the main thread when not running in a
	// library. This can be removed when we are confident that all
	// FreeBSD users are running a patched kernel. See issue #15658.
	if gp := getg(); !isarchive && !islibrary && gp.m == &m0 && gp == gp.m.g0 {
	st := stackt{ss_flags: _SS_DISABLE}
	sigaltstack(&st, nil)
	}

	minitSignals()
	}

	// Called from dropm to undo the effect of an minit.
	//
	//go:nosplit
	func unminit() {
	unminitSignals()
	}

	// Called from exitm, but not from drop, to undo the effect of thread-owned
	// resources in minit, semacreate, or elsewhere. Do not take locks after calling this.
	func mdestroy(mp *m) {
	}

	func sigtramp()

	type sigactiont struct {
	sa_handler uintptr
	sa_flags int32
	sa_mask sigset
	}

	// See os_freebsd2.go, os_freebsd_amd64.go for setsig function

	//go:nosplit
	//go:nowritebarrierrec
	func setsigstack(i uint32) {
	var sa sigactiont
	sigaction(i, nil, &sa)
	if sa.sa_flags&_SA_ONSTACK != 0 {
	return
	}
	sa.sa_flags \|= _SA_ONSTACK
	sigaction(i, &sa, nil)
	}

	//go:nosplit
	//go:nowritebarrierrec
	func getsig(i uint32) uintptr {
	var sa sigactiont
	sigaction(i, nil, &sa)
	return sa.sa_handler
	}

	// setSignalstackSP sets the ss_sp field of a stackt.
	//
	//go:nosplit
	func setSignalstackSP(s *stackt, sp uintptr) {
	s.ss_sp = sp
	}

	//go:nosplit
	//go:nowritebarrierrec
	func sigaddset(mask *sigset, i int) {
	mask.__bits[(i-1)/32] \|= 1 << ((uint32(i) - 1) & 31)
	}

	func sigdelset(mask *sigset, i int) {
	mask.__bits[(i-1)/32] &^= 1 << ((uint32(i) - 1) & 31)
	}

	//go:nosplit
	func (c *sigctxt) fixsigcode(sig uint32) {
	}

	func setProcessCPUProfiler(hz int32) {
	setProcessCPUProfilerTimer(hz)
	}

	func setThreadCPUProfiler(hz int32) {
	setThreadCPUProfilerHz(hz)
	}

	//go:nosplit
	func validSIGPROF(mp m, c sigctxt) bool {
	return true
	}

	func sysargs(argc int32, argv **byte) {
	n := argc + 1

	// skip over argv, envp to get to auxv
	for argv_index(argv, n) != nil {
	n++
	}

	// skip NULL separator
	n++

	// now argv+n is auxv
	auxv := ([1 << 28]uintptr)(add(unsafe.Pointer(argv), uintptr(n)goarch.PtrSize))
	sysauxv(auxv[:])
	}

	const (
	_AT_NULL = 0 // Terminates the vector
	_AT_PAGESZ = 6 // Page size in bytes
	_AT_TIMEKEEP = 22 // Pointer to timehands.
	_AT_HWCAP = 25 // CPU feature flags
	_AT_HWCAP2 = 26 // CPU feature flags 2
	)

	func sysauxv(auxv []uintptr) {
	for i := 0; auxv[i] != _AT_NULL; i += 2 {
	tag, val := auxv[i], auxv[i+1]
	switch tag {
	// _AT_NCPUS from auxv shouldn't be used due to golang.org/issue/15206
	case _AT_PAGESZ:
	physPageSize = val
	case _AT_TIMEKEEP:
	timekeepSharedPage = (*vdsoTimekeep)(unsafe.Pointer(val))
	}

	archauxv(tag, val)
	}
	}

	// sysSigaction calls the sigaction system call.
	//
	//go:nosplit
	func sysSigaction(sig uint32, new, old *sigactiont) {
	// Use system stack to avoid split stack overflow on amd64
	if asmSigaction(uintptr(sig), new, old) != 0 {
	systemstack(func() {
	throw("sigaction failed")
	})
	}
	}

	// asmSigaction is implemented in assembly.
	//
	//go:noescape
	func asmSigaction(sig uintptr, new, old *sigactiont) int32

	// raise sends a signal to the calling thread.
	//
	// It must be nosplit because it is used by the signal handler before
	// it definitely has a Go stack.
	//
	//go:nosplit
	func raise(sig uint32) {
	thr_kill(thr_self(), int(sig))
	}

	func signalM(mp *m, sig int) {
	thr_kill(thread(mp.procid), sig)
	}

	// sigPerThreadSyscall is only used on linux, so we assign a bogus signal
	// number.
	const sigPerThreadSyscall = 1 << 31

	//go:nosplit
	func runPerThreadSyscall() {
	throw("runPerThreadSyscall only valid on linux")
	}