[dev.cc] runtime: convert freebsd to Go

It builds.
Don't know if it works, but it's a lot closer than having everything in C.

LGTM=r
R=r
CC=golang-codereviews
https://codereview.appspot.com/168590043

1 files changed, 221 insertions, 0 deletions

diff --git a/src/runtime/os1_freebsd.go b/src/runtime/os1_freebsd.go
new file mode 100644
index 000000000..0b2fedad9
--- /dev/null
+++ b/src/runtime/os1_freebsd.go
@@ -0,0 +1,221 @@
+// 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 "unsafe"
+
+// From FreeBSD's <sys/sysctl.h>
+const (
+	_CTL_HW  = 6
+	_HW_NCPU = 3
+)
+
+var sigset_none = sigset{}
+var sigset_all = sigset{[4]uint32{^uint32(0), ^uint32(0), ^uint32(0), ^uint32(0)}}
+
+func getncpu() int32 {
+	mib := [2]uint32{_CTL_HW, _HW_NCPU}
+	out := uint32(0)
+	nout := unsafe.Sizeof(out)
+	ret := sysctl(&mib[0], 2, (*byte)(unsafe.Pointer(&out)), &nout, nil, 0)
+	if ret >= 0 {
+		return int32(out)
+	}
+	return 1
+}
+
+// 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.c for comments.
+
+//go:nosplit
+func futexsleep(addr *uint32, val uint32, ns int64) {
+	onM(func() {
+		futexsleep1(addr, val, ns)
+	})
+}
+
+func futexsleep1(addr *uint32, val uint32, ns int64) {
+	var tsp *timespec
+	if ns >= 0 {
+		var ts timespec
+		ts.tv_nsec = 0
+		ts.set_sec(timediv(ns, 1000000000, (*int32)(unsafe.Pointer(&ts.tv_nsec))))
+		tsp = &ts
+	}
+	ret := sys_umtx_op(addr, _UMTX_OP_WAIT_UINT_PRIVATE, val, nil, tsp)
+	if ret >= 0 || ret == -_EINTR {
+		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, nil, nil)
+	if ret >= 0 {
+		return
+	}
+
+	onM(func() {
+		print("umtx_wake_addr=", addr, " ret=", ret, "\n")
+	})
+}
+
+func thr_start()
+
+func newosproc(mp *m, stk unsafe.Pointer) {
+	if false {
+		print("newosproc stk=", stk, " m=", mp, " g=", mp.g0, " thr_start=", funcPC(thr_start), " id=", mp.id, "/", mp.tls[0], " ostk=", &mp, "\n")
+	}
+
+	// NOTE(rsc): This code is confused. stackbase is the top of the stack
+	// and is equal to stk. However, it's working, so I'm not changing it.
+	param := thrparam{
+		start_func: funcPC(thr_start),
+		arg:        unsafe.Pointer(mp),
+		stack_base: mp.g0.stack.hi,
+		stack_size: uintptr(stk) - mp.g0.stack.hi,
+		child_tid:  unsafe.Pointer(&mp.procid),
+		parent_tid: nil,
+		tls_base:   unsafe.Pointer(&mp.tls[0]),
+		tls_size:   unsafe.Sizeof(mp.tls),
+	}
+	mp.tls[0] = uintptr(mp.id) // so 386 asm can find it
+
+	var oset sigset
+	sigprocmask(&sigset_all, &oset)
+	thr_new(&param, int32(unsafe.Sizeof(param)))
+	sigprocmask(&oset, nil)
+}
+
+func osinit() {
+	ncpu = getncpu()
+}
+
+var urandom_data [_HashRandomBytes]byte
+var urandom_dev = []byte("/dev/random\x00")
+
+//go:nosplit
+func get_random_data(rnd *unsafe.Pointer, rnd_len *int32) {
+	fd := open(&urandom_dev[0], 0 /* O_RDONLY */, 0)
+	if read(fd, unsafe.Pointer(&urandom_data), _HashRandomBytes) == _HashRandomBytes {
+		*rnd = unsafe.Pointer(&urandom_data[0])
+		*rnd_len = _HashRandomBytes
+	} else {
+		*rnd = nil
+		*rnd_len = 0
+	}
+	close(fd)
+}
+
+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, can not allocate memory.
+func minit() {
+	_g_ := getg()
+
+	// m.procid is a uint64, but thr_new writes a uint32 on 32-bit systems.
+	// Fix it up. (Only matters on big-endian, but be clean anyway.)
+	if ptrSize == 4 {
+		_g_.m.procid = uint64(*(*uint32)(unsafe.Pointer(&_g_.m.procid)))
+	}
+
+	// Initialize signal handling.
+	signalstack((*byte)(unsafe.Pointer(_g_.m.gsignal.stack.lo)), 32*1024)
+	sigprocmask(&sigset_none, nil)
+}
+
+// Called from dropm to undo the effect of an minit.
+func unminit() {
+	signalstack(nil, 0)
+}
+
+func memlimit() uintptr {
+	/*
+		TODO: Convert to Go when something actually uses the result.
+		Rlimit rl;
+		extern byte runtime·text[], runtime·end[];
+		uintptr used;
+
+		if(runtime·getrlimit(RLIMIT_AS, &rl) != 0)
+			return 0;
+		if(rl.rlim_cur >= 0x7fffffff)
+			return 0;
+
+		// Estimate our VM footprint excluding the heap.
+		// Not an exact science: use size of binary plus
+		// some room for thread stacks.
+		used = runtime·end - runtime·text + (64<<20);
+		if(used >= rl.rlim_cur)
+			return 0;
+
+		// If there's not at least 16 MB left, we're probably
+		// not going to be able to do much.  Treat as no limit.
+		rl.rlim_cur -= used;
+		if(rl.rlim_cur < (16<<20))
+			return 0;
+
+		return rl.rlim_cur - used;
+	*/
+
+	return 0
+}
+
+func sigtramp()
+
+type sigactiont struct {
+	sa_handler uintptr
+	sa_flags   int32
+	sa_mask    sigset
+}
+
+func setsig(i int32, fn uintptr, restart bool) {
+	var sa sigactiont
+	sa.sa_flags = _SA_SIGINFO | _SA_ONSTACK
+	if restart {
+		sa.sa_flags |= _SA_RESTART
+	}
+	sa.sa_mask = sigset_all
+	if fn == funcPC(sighandler) {
+		fn = funcPC(sigtramp)
+	}
+	sa.sa_handler = fn
+	sigaction(i, &sa, nil)
+}
+func getsig(i int32) uintptr {
+	var sa sigactiont
+	sigaction(i, nil, &sa)
+	if sa.sa_handler == funcPC(sigtramp) {
+		return funcPC(sighandler)
+	}
+	return sa.sa_handler
+}
+
+func signalstack(p *byte, n int32) {
+	var st stackt
+	st.ss_sp = uintptr(unsafe.Pointer(p))
+	st.ss_size = uintptr(n)
+	st.ss_flags = 0
+	if p == nil {
+		st.ss_flags = _SS_DISABLE
+	}
+	sigaltstack(&st, nil)
+}
+
+func unblocksignals() {
+	sigprocmask(&sigset_none, nil)
+}