runtime: add hurd netpoll and semaphore support
Patch by Svante Signell.
Change-Id: I6f6ba6cf988e75e43c3fd4fc0341b45e4866dbcd
Reviewed-on: https://go-review.googlesource.com/c/160827
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/libgo/go/runtime/netpoll.go b/libgo/go/runtime/netpoll.go
index e71ba08..6d39114 100644
--- a/libgo/go/runtime/netpoll.go
+++ b/libgo/go/runtime/netpoll.go
@@ -102,7 +102,7 @@
// descriptor being used by netpoll.
func poll_runtime_isPollServerDescriptor(fd uintptr) bool {
fds := netpolldescriptor()
- if GOOS != "aix" {
+ if GOOS != "aix" && GOOS != "hurd" {
return fd == fds
} else {
// AIX have a pipe in its netpoll implementation.
@@ -178,8 +178,8 @@
if err != 0 {
return err
}
- // As for now only Solaris and AIX use level-triggered IO.
- if GOOS == "solaris" || GOOS == "aix" {
+ // As for now only Solaris, AIX and Hurd use level-triggered IO.
+ if GOOS == "solaris" || GOOS == "aix" || GOOS == "hurd" {
netpollarm(pd, mode)
}
for !netpollblock(pd, int32(mode), false) {
diff --git a/libgo/go/runtime/netpoll_hurd.go b/libgo/go/runtime/netpoll_hurd.go
new file mode 100644
index 0000000..b74ad2f
--- /dev/null
+++ b/libgo/go/runtime/netpoll_hurd.go
@@ -0,0 +1,240 @@
+// Copyright 2019 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"
+
+// FIXME: Improve network poller for hurd.
+// This is based on the former libgo/runtime/netpoll_select.c implementation
+// except that it uses poll instead of select and is written in Go.
+// It's also based on Solaris implementation for the arming mechanisms
+// Inspiration was also taken from netpoll_aix.go and netpoll_solaris.go
+
+//From /usr/include/x86_64-linux-gnu/sys/poll.h
+//go:noescape
+//extern poll
+func libc_poll(pfds *pollfd, nfds int32, timeout int32) int32
+
+//go:noescape
+//extern pipe2
+func libc_pipe2(fd *int32, flags int32) int32
+
+//pollfd represents the poll structure for GNU/Hurd operating system.
+type pollfd struct {
+ fd int32 // File descriptor to poll.
+ events int16 // Types of events poller cares about.
+ revents int16 // Types of events that actually occurred.
+}
+
+//From /usr/include/i386-gnu/bits/poll.h
+const _POLLIN = 01 // There is data to read.
+const _POLLPRI = 02 // There is urgent data to read.
+const _POLLOUT = 04 // Writing now will not block.
+const _POLLERR = 010 // Error condition.
+const _POLLHUP = 020 // Hung up.
+const _POLLNVAL = 040 // Invalid polling request.
+
+var (
+ pfds []pollfd
+ pds []*pollDesc
+ mtxpoll mutex
+ mtxset mutex
+ rdwake int32
+ wrwake int32
+ pendingUpdates int32
+)
+
+const pollVerbose = false
+
+func netpollinit() {
+ var p [2]int32
+
+ // Create the pipe we use to wakeup poll.
+ if err := libc_pipe2(&p[0], _O_CLOEXEC|_O_NONBLOCK); err < 0 {
+ throw("runtime:netpollinit(): failed to create pipe2")
+ }
+ rdwake = p[0]
+ wrwake = p[1]
+
+ // Pre-allocate array of pollfd structures for poll.
+ if pollVerbose {
+ println("*** allocating")
+ }
+ pfds = make([]pollfd, 1, 128)
+ if pollVerbose {
+ println("*** allocating done", &pfds[0])
+ }
+
+ // Poll the read side of the pipe.
+ pfds[0].fd = int32(rdwake)
+ pfds[0].events = int16(_POLLIN)
+ pfds[0].revents = int16(0)
+
+ pds = make([]*pollDesc, 1, 128)
+ // Checks for pd != nil are made in netpoll.
+ pds[0] = nil
+}
+
+func netpolldescriptor() uintptr {
+ // Both fds must be returned.
+ if rdwake > 0xFFFF || wrwake > 0xFFFF {
+ throw("netpolldescriptor: invalid fd number")
+ }
+ return uintptr(rdwake<<16 | wrwake)
+}
+
+// netpollwakeup writes on wrwake to wakeup poll before any changes.
+func netpollwakeup() {
+ if pendingUpdates == 0 {
+ pendingUpdates = 1
+ if pollVerbose {
+ println("*** writing 1 byte")
+ }
+ b := [1]byte{0}
+ write(uintptr(wrwake), unsafe.Pointer(&b[0]), 1)
+ }
+}
+
+func netpollopen(fd uintptr, pd *pollDesc) int32 {
+ if pollVerbose {
+ println("*** netpollopen", fd)
+ }
+ lock(&mtxpoll)
+ netpollwakeup()
+
+ lock(&mtxset)
+ unlock(&mtxpoll)
+
+ pd.user = uint32(len(pfds))
+ pfds = append(pfds, pollfd{fd: int32(fd)})
+ pds = append(pds, pd)
+ unlock(&mtxset)
+ return 0
+}
+
+func netpollclose(fd uintptr) int32 {
+ if pollVerbose {
+ println("*** netpollclose", fd)
+ }
+ lock(&mtxpoll)
+ netpollwakeup()
+
+ lock(&mtxset)
+ unlock(&mtxpoll)
+
+ for i := 0; i < len(pfds); i++ {
+ if pfds[i].fd == int32(fd) {
+ pfds[i] = pfds[len(pfds)-1]
+ pfds = pfds[:len(pfds)-1]
+
+ pds[i] = pds[len(pds)-1]
+ pds[i].user = uint32(i)
+ pds = pds[:len(pds)-1]
+ break
+ }
+ }
+ unlock(&mtxset)
+ return 0
+}
+
+func netpollarm(pd *pollDesc, mode int) {
+ if pollVerbose {
+ println("*** netpollarm", pd.fd, mode)
+ }
+ lock(&mtxpoll)
+ netpollwakeup()
+
+ lock(&mtxset)
+ unlock(&mtxpoll)
+
+ switch mode {
+ case 'r':
+ pfds[pd.user].events |= _POLLIN
+ case 'w':
+ pfds[pd.user].events |= _POLLOUT
+ }
+ unlock(&mtxset)
+}
+
+// polls for ready network connections
+// returns list of goroutines that become runnable
+//go:nowritebarrierrec
+func netpoll(block bool) gList {
+ timeout := int32(0)
+ if !block {
+ timeout = 0
+ return gList{}
+ }
+ if pollVerbose {
+ println("*** netpoll", block)
+ }
+retry:
+ lock(&mtxpoll)
+ lock(&mtxset)
+ pendingUpdates = 0
+ unlock(&mtxpoll)
+
+ if pollVerbose {
+ println("*** netpoll before poll")
+ }
+ n := libc_poll(&pfds[0], int32(len(pfds)), timeout)
+ if pollVerbose {
+ println("*** netpoll after poll", n)
+ }
+ if n < 0 {
+ e := errno()
+ if e != _EINTR {
+ println("errno=", e, " len(pfds)=", len(pfds))
+ throw("poll failed")
+ }
+ if pollVerbose {
+ println("*** poll failed")
+ }
+ unlock(&mtxset)
+ goto retry
+ }
+ // Check if some descriptors need to be changed
+ if n != 0 && pfds[0].revents&(_POLLIN|_POLLHUP|_POLLERR) != 0 {
+ var b [1]byte
+ for read(rdwake, unsafe.Pointer(&b[0]), 1) == 1 {
+ if pollVerbose {
+ println("*** read 1 byte from pipe")
+ }
+ }
+ // Do not look at the other fds in this case as the mode may have changed
+ // XXX only additions of flags are made, so maybe it is ok
+ unlock(&mtxset)
+ goto retry
+ }
+ var toRun gList
+ for i := 0; i < len(pfds) && n > 0; i++ {
+ pfd := &pfds[i]
+
+ var mode int32
+ if pfd.revents&(_POLLIN|_POLLHUP|_POLLERR) != 0 {
+ mode += 'r'
+ pfd.events &= ^_POLLIN
+ }
+ if pfd.revents&(_POLLOUT|_POLLHUP|_POLLERR) != 0 {
+ mode += 'w'
+ pfd.events &= ^_POLLOUT
+ }
+ if mode != 0 {
+ if pollVerbose {
+ println("*** netpollready i=", i, "revents=", pfd.revents, "events=", pfd.events, "pd=", pds[i])
+ }
+ netpollready(&toRun, pds[i], mode)
+ n--
+ }
+ }
+ unlock(&mtxset)
+ if block && toRun.empty() {
+ goto retry
+ }
+ if pollVerbose {
+ println("*** netpoll returning end")
+ }
+ return toRun
+}
diff --git a/libgo/go/runtime/os_hurd.go b/libgo/go/runtime/os_hurd.go
new file mode 100644
index 0000000..1282553
--- /dev/null
+++ b/libgo/go/runtime/os_hurd.go
@@ -0,0 +1,87 @@
+// Copyright 2019 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.
+
+// This file is derived from os_solaris.go.
+
+package runtime
+
+import "unsafe"
+
+type mOS struct {
+ waitsema uintptr // semaphore for parking on locks
+}
+
+//extern malloc
+func libc_malloc(uintptr) unsafe.Pointer
+
+//go:noescape
+//extern sem_init
+func sem_init(sem *_sem_t, pshared int32, value uint32) int32
+
+//go:noescape
+//extern sem_wait
+func sem_wait(sem *_sem_t) int32
+
+//go:noescape
+//extern sem_post
+func sem_post(sem *_sem_t) int32
+
+//go:noescape
+//extern sem_timedwait
+func sem_timedwait(sem *_sem_t, timeout *timespec) int32
+
+//go:nosplit
+func semacreate(mp *m) {
+ if mp.mos.waitsema != 0 {
+ return
+ }
+
+ var sem *_sem_t
+
+ // Call libc's malloc rather than malloc. This will
+ // allocate space on the C heap. We can't call malloc
+ // here because it could cause a deadlock.
+ sem = (*_sem_t)(libc_malloc(unsafe.Sizeof(*sem)))
+ if sem_init(sem, 0, 0) != 0 {
+ throw("sem_init")
+ }
+ mp.mos.waitsema = uintptr(unsafe.Pointer(sem))
+}
+
+//go:nosplit
+func semasleep(ns int64) int32 {
+ _m_ := getg().m
+ if ns >= 0 {
+ var ts timespec
+ ts.set_sec(ns / 1000000000)
+ ts.set_nsec(int32(ns % 1000000000))
+
+ if sem_timedwait((*_sem_t)(unsafe.Pointer(_m_.mos.waitsema)), &ts) != 0 {
+ err := errno()
+ if err == _ETIMEDOUT || err == _EAGAIN || err == _EINTR {
+ return -1
+ }
+ throw("sem_timedwait")
+ }
+ return 0
+ }
+ for {
+ r1 := sem_wait((*_sem_t)(unsafe.Pointer(_m_.mos.waitsema)))
+ if r1 == 0 {
+ break
+ }
+ if errno() == _EINTR {
+ continue
+ }
+ throw("sem_wait")
+ }
+ return 0
+}
+
+//go:nosplit
+func semawakeup(mp *m) {
+ if sem_post((*_sem_t)(unsafe.Pointer(mp.mos.waitsema))) != 0 {
+ throw("sem_post")
+ }
+}
