1 files changed, 541 insertions, 0 deletions
diff --git a/src/runtime/os_plan9.go b/src/runtime/os_plan9.go
new file mode 100644
index 0000000..2bb6ec0
--- /dev/null
+++ b/src/runtime/os_plan9.go
@@ -0,0 +1,541 @@
+// Copyright 2010 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"
+	"runtime/internal/atomic"
+	"unsafe"
+)
+
+type mOS struct {
+	waitsemacount uint32
+	notesig       *int8
+	errstr        *byte
+	ignoreHangup  bool
+}
+
+func closefd(fd int32) int32
+
+//go:noescape
+func open(name *byte, mode, perm int32) int32
+
+//go:noescape
+func pread(fd int32, buf unsafe.Pointer, nbytes int32, offset int64) int32
+
+//go:noescape
+func pwrite(fd int32, buf unsafe.Pointer, nbytes int32, offset int64) int32
+
+func seek(fd int32, offset int64, whence int32) int64
+
+//go:noescape
+func exits(msg *byte)
+
+//go:noescape
+func brk_(addr unsafe.Pointer) int32
+
+func sleep(ms int32) int32
+
+func rfork(flags int32) int32
+
+//go:noescape
+func plan9_semacquire(addr *uint32, block int32) int32
+
+//go:noescape
+func plan9_tsemacquire(addr *uint32, ms int32) int32
+
+//go:noescape
+func plan9_semrelease(addr *uint32, count int32) int32
+
+//go:noescape
+func notify(fn unsafe.Pointer) int32
+
+func noted(mode int32) int32
+
+//go:noescape
+func nsec(*int64) int64
+
+//go:noescape
+func sigtramp(ureg, note unsafe.Pointer)
+
+func setfpmasks()
+
+//go:noescape
+func tstart_plan9(newm *m)
+
+func errstr() string
+
+type _Plink uintptr
+
+//go:linkname os_sigpipe os.sigpipe
+func os_sigpipe() {
+	throw("too many writes on closed pipe")
+}
+
+func sigpanic() {
+	g := getg()
+	if !canpanic(g) {
+		throw("unexpected signal during runtime execution")
+	}
+
+	note := gostringnocopy((*byte)(unsafe.Pointer(g.m.notesig)))
+	switch g.sig {
+	case _SIGRFAULT, _SIGWFAULT:
+		i := indexNoFloat(note, "addr=")
+		if i >= 0 {
+			i += 5
+		} else if i = indexNoFloat(note, "va="); i >= 0 {
+			i += 3
+		} else {
+			panicmem()
+		}
+		addr := note[i:]
+		g.sigcode1 = uintptr(atolwhex(addr))
+		if g.sigcode1 < 0x1000 {
+			panicmem()
+		}
+		if g.paniconfault {
+			panicmemAddr(g.sigcode1)
+		}
+		print("unexpected fault address ", hex(g.sigcode1), "\n")
+		throw("fault")
+	case _SIGTRAP:
+		if g.paniconfault {
+			panicmem()
+		}
+		throw(note)
+	case _SIGINTDIV:
+		panicdivide()
+	case _SIGFLOAT:
+		panicfloat()
+	default:
+		panic(errorString(note))
+	}
+}
+
+// indexNoFloat is bytealg.IndexString but safe to use in a note
+// handler.
+func indexNoFloat(s, t string) int {
+	if len(t) == 0 {
+		return 0
+	}
+	for i := 0; i < len(s); i++ {
+		if s[i] == t[0] && hasPrefix(s[i:], t) {
+			return i
+		}
+	}
+	return -1
+}
+
+func atolwhex(p string) int64 {
+	for hasPrefix(p, " ") || hasPrefix(p, "\t") {
+		p = p[1:]
+	}
+	neg := false
+	if hasPrefix(p, "-") || hasPrefix(p, "+") {
+		neg = p[0] == '-'
+		p = p[1:]
+		for hasPrefix(p, " ") || hasPrefix(p, "\t") {
+			p = p[1:]
+		}
+	}
+	var n int64
+	switch {
+	case hasPrefix(p, "0x"), hasPrefix(p, "0X"):
+		p = p[2:]
+		for ; len(p) > 0; p = p[1:] {
+			if '0' <= p[0] && p[0] <= '9' {
+				n = n*16 + int64(p[0]-'0')
+			} else if 'a' <= p[0] && p[0] <= 'f' {
+				n = n*16 + int64(p[0]-'a'+10)
+			} else if 'A' <= p[0] && p[0] <= 'F' {
+				n = n*16 + int64(p[0]-'A'+10)
+			} else {
+				break
+			}
+		}
+	case hasPrefix(p, "0"):
+		for ; len(p) > 0 && '0' <= p[0] && p[0] <= '7'; p = p[1:] {
+			n = n*8 + int64(p[0]-'0')
+		}
+	default:
+		for ; len(p) > 0 && '0' <= p[0] && p[0] <= '9'; p = p[1:] {
+			n = n*10 + int64(p[0]-'0')
+		}
+	}
+	if neg {
+		n = -n
+	}
+	return n
+}
+
+type sigset struct{}
+
+// 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) {
+	// Initialize stack and goroutine for note handling.
+	mp.gsignal = malg(32 * 1024)
+	mp.gsignal.m = mp
+	mp.notesig = (*int8)(mallocgc(_ERRMAX, nil, true))
+	// Initialize stack for handling strings from the
+	// errstr system call, as used in package syscall.
+	mp.errstr = (*byte)(mallocgc(_ERRMAX, nil, true))
+}
+
+func sigsave(p *sigset) {
+}
+
+func msigrestore(sigmask sigset) {
+}
+
+//go:nosplit
+//go:nowritebarrierrec
+func clearSignalHandlers() {
+}
+
+func sigblock(exiting bool) {
+}
+
+// Called to initialize a new m (including the bootstrap m).
+// Called on the new thread, cannot allocate memory.
+func minit() {
+	if atomic.Load(&exiting) != 0 {
+		exits(&emptystatus[0])
+	}
+	// Mask all SSE floating-point exceptions
+	// when running on the 64-bit kernel.
+	setfpmasks()
+}
+
+// Called from dropm to undo the effect of an minit.
+func unminit() {
+}
+
+// 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) {
+}
+
+var sysstat = []byte("/dev/sysstat\x00")
+
+func getproccount() int32 {
+	var buf [2048]byte
+	fd := open(&sysstat[0], _OREAD, 0)
+	if fd < 0 {
+		return 1
+	}
+	ncpu := int32(0)
+	for {
+		n := read(fd, unsafe.Pointer(&buf), int32(len(buf)))
+		if n <= 0 {
+			break
+		}
+		for i := int32(0); i < n; i++ {
+			if buf[i] == '\n' {
+				ncpu++
+			}
+		}
+	}
+	closefd(fd)
+	if ncpu == 0 {
+		ncpu = 1
+	}
+	return ncpu
+}
+
+var devswap = []byte("/dev/swap\x00")
+var pagesize = []byte(" pagesize\n")
+
+func getPageSize() uintptr {
+	var buf [2048]byte
+	var pos int
+	fd := open(&devswap[0], _OREAD, 0)
+	if fd < 0 {
+		// There's not much we can do if /dev/swap doesn't
+		// exist. However, nothing in the memory manager uses
+		// this on Plan 9, so it also doesn't really matter.
+		return minPhysPageSize
+	}
+	for pos < len(buf) {
+		n := read(fd, unsafe.Pointer(&buf[pos]), int32(len(buf)-pos))
+		if n <= 0 {
+			break
+		}
+		pos += int(n)
+	}
+	closefd(fd)
+	text := buf[:pos]
+	// Find "<n> pagesize" line.
+	bol := 0
+	for i, c := range text {
+		if c == '\n' {
+			bol = i + 1
+		}
+		if bytesHasPrefix(text[i:], pagesize) {
+			// Parse number at the beginning of this line.
+			return uintptr(_atoi(text[bol:]))
+		}
+	}
+	// Again, the page size doesn't really matter, so use a fallback.
+	return minPhysPageSize
+}
+
+func bytesHasPrefix(s, prefix []byte) bool {
+	if len(s) < len(prefix) {
+		return false
+	}
+	for i, p := range prefix {
+		if s[i] != p {
+			return false
+		}
+	}
+	return true
+}
+
+var pid = []byte("#c/pid\x00")
+
+func getpid() uint64 {
+	var b [20]byte
+	fd := open(&pid[0], 0, 0)
+	if fd >= 0 {
+		read(fd, unsafe.Pointer(&b), int32(len(b)))
+		closefd(fd)
+	}
+	c := b[:]
+	for c[0] == ' ' || c[0] == '\t' {
+		c = c[1:]
+	}
+	return uint64(_atoi(c))
+}
+
+func osinit() {
+	initBloc()
+	ncpu = getproccount()
+	physPageSize = getPageSize()
+	getg().m.procid = getpid()
+}
+
+//go:nosplit
+func crash() {
+	notify(nil)
+	*(*int)(nil) = 0
+}
+
+//go:nosplit
+func getRandomData(r []byte) {
+	// inspired by wyrand see hash32.go for detail
+	t := nanotime()
+	v := getg().m.procid ^ uint64(t)
+
+	for len(r) > 0 {
+		v ^= 0xa0761d6478bd642f
+		v *= 0xe7037ed1a0b428db
+		size := 8
+		if len(r) < 8 {
+			size = len(r)
+		}
+		for i := 0; i < size; i++ {
+			r[i] = byte(v >> (8 * i))
+		}
+		r = r[size:]
+		v = v>>32 | v<<32
+	}
+}
+
+func initsig(preinit bool) {
+	if !preinit {
+		notify(unsafe.Pointer(abi.FuncPCABI0(sigtramp)))
+	}
+}
+
+//go:nosplit
+func osyield() {
+	sleep(0)
+}
+
+//go:nosplit
+func osyield_no_g() {
+	osyield()
+}
+
+//go:nosplit
+func usleep(µs uint32) {
+	ms := int32(µs / 1000)
+	if ms == 0 {
+		ms = 1
+	}
+	sleep(ms)
+}
+
+//go:nosplit
+func usleep_no_g(usec uint32) {
+	usleep(usec)
+}
+
+//go:nosplit
+func nanotime1() int64 {
+	var scratch int64
+	ns := nsec(&scratch)
+	// TODO(aram): remove hack after I fix _nsec in the pc64 kernel.
+	if ns == 0 {
+		return scratch
+	}
+	return ns
+}
+
+var goexits = []byte("go: exit ")
+var emptystatus = []byte("\x00")
+var exiting uint32
+
+func goexitsall(status *byte) {
+	var buf [_ERRMAX]byte
+	if !atomic.Cas(&exiting, 0, 1) {
+		return
+	}
+	getg().m.locks++
+	n := copy(buf[:], goexits)
+	n = copy(buf[n:], gostringnocopy(status))
+	pid := getpid()
+	for mp := (*m)(atomic.Loadp(unsafe.Pointer(&allm))); mp != nil; mp = mp.alllink {
+		if mp.procid != 0 && mp.procid != pid {
+			postnote(mp.procid, buf[:])
+		}
+	}
+	getg().m.locks--
+}
+
+var procdir = []byte("/proc/")
+var notefile = []byte("/note\x00")
+
+func postnote(pid uint64, msg []byte) int {
+	var buf [128]byte
+	var tmp [32]byte
+	n := copy(buf[:], procdir)
+	n += copy(buf[n:], itoa(tmp[:], pid))
+	copy(buf[n:], notefile)
+	fd := open(&buf[0], _OWRITE, 0)
+	if fd < 0 {
+		return -1
+	}
+	len := findnull(&msg[0])
+	if write1(uintptr(fd), unsafe.Pointer(&msg[0]), int32(len)) != int32(len) {
+		closefd(fd)
+		return -1
+	}
+	closefd(fd)
+	return 0
+}
+
+//go:nosplit
+func exit(e int32) {
+	var status []byte
+	if e == 0 {
+		status = emptystatus
+	} else {
+		// build error string
+		var tmp [32]byte
+		status = append(itoa(tmp[:len(tmp)-1], uint64(e)), 0)
+	}
+	goexitsall(&status[0])
+	exits(&status[0])
+}
+
+// May run with m.p==nil, so write barriers are not allowed.
+//go:nowritebarrier
+func newosproc(mp *m) {
+	if false {
+		print("newosproc mp=", mp, " ostk=", &mp, "\n")
+	}
+	pid := rfork(_RFPROC | _RFMEM | _RFNOWAIT)
+	if pid < 0 {
+		throw("newosproc: rfork failed")
+	}
+	if pid == 0 {
+		tstart_plan9(mp)
+	}
+}
+
+func exitThread(wait *atomic.Uint32) {
+	// We should never reach exitThread on Plan 9 because we let
+	// the OS clean up threads.
+	throw("exitThread")
+}
+
+//go:nosplit
+func semacreate(mp *m) {
+}
+
+//go:nosplit
+func semasleep(ns int64) int {
+	_g_ := getg()
+	if ns >= 0 {
+		ms := timediv(ns, 1000000, nil)
+		if ms == 0 {
+			ms = 1
+		}
+		ret := plan9_tsemacquire(&_g_.m.waitsemacount, ms)
+		if ret == 1 {
+			return 0 // success
+		}
+		return -1 // timeout or interrupted
+	}
+	for plan9_semacquire(&_g_.m.waitsemacount, 1) < 0 {
+		// interrupted; try again (c.f. lock_sema.go)
+	}
+	return 0 // success
+}
+
+//go:nosplit
+func semawakeup(mp *m) {
+	plan9_semrelease(&mp.waitsemacount, 1)
+}
+
+//go:nosplit
+func read(fd int32, buf unsafe.Pointer, n int32) int32 {
+	return pread(fd, buf, n, -1)
+}
+
+//go:nosplit
+func write1(fd uintptr, buf unsafe.Pointer, n int32) int32 {
+	return pwrite(int32(fd), buf, n, -1)
+}
+
+var _badsignal = []byte("runtime: signal received on thread not created by Go.\n")
+
+// This runs on a foreign stack, without an m or a g. No stack split.
+//go:nosplit
+func badsignal2() {
+	pwrite(2, unsafe.Pointer(&_badsignal[0]), int32(len(_badsignal)), -1)
+	exits(&_badsignal[0])
+}
+
+func raisebadsignal(sig uint32) {
+	badsignal2()
+}
+
+func _atoi(b []byte) int {
+	n := 0
+	for len(b) > 0 && '0' <= b[0] && b[0] <= '9' {
+		n = n*10 + int(b[0]) - '0'
+		b = b[1:]
+	}
+	return n
+}
+
+func signame(sig uint32) string {
+	if sig >= uint32(len(sigtable)) {
+		return ""
+	}
+	return sigtable[sig].name
+}
+
+const preemptMSupported = false
+
+func preemptM(mp *m) {
+	// Not currently supported.
+	//
+	// TODO: Use a note like we use signals on POSIX OSes
+}