runtime: add AIX operating system

This commit adds AIX operating system to runtime package for ppc64
architecture.

Only new files and minor changes are in this commit. Others
modifications in files like asm_ppc64.s  will be in separate commits.

Updates: #25893

Change-Id: I9c5e073f5f3debb43b004ad1167694a5afd31cfd
Reviewed-on: https://go-review.googlesource.com/c/138716
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

1 files changed, 262 insertions, 0 deletions

diff --git a/src/runtime/os_aix.go b/src/runtime/os_aix.go
new file mode 100644
index 0000000000..31590f22d8
--- /dev/null
+++ b/src/runtime/os_aix.go
@@ -0,0 +1,262 @@
+// Copyright 2018 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.
+
+// +build aix
+
+package runtime
+
+import (
+	"unsafe"
+)
+
+const (
+	threadStackSize = 0x100000 // size of a thread stack allocated by OS
+)
+
+// funcDescriptor is a structure representing a function descriptor
+// A variable with this type is always created in assembler
+type funcDescriptor struct {
+	fn         uintptr
+	toc        uintptr
+	envPointer uintptr // unused in Golang
+}
+
+type mOS struct {
+	waitsema uintptr // semaphore for parking on locks
+	perrno   uintptr // pointer to tls errno
+}
+
+//go:nosplit
+func semacreate(mp *m) {
+	if mp.waitsema != 0 {
+		return
+	}
+
+	var sem *semt
+
+	// Call libc's malloc rather than malloc. This will
+	// allocate space on the C heap. We can't call mallocgc
+	// here because it could cause a deadlock.
+	sem = (*semt)(malloc(unsafe.Sizeof(*sem)))
+	if sem_init(sem, 0, 0) != 0 {
+		throw("sem_init")
+	}
+	mp.waitsema = uintptr(unsafe.Pointer(sem))
+}
+
+//go:nosplit
+func semasleep(ns int64) int32 {
+	_m_ := getg().m
+	if ns >= 0 {
+		var ts timespec
+
+		if clock_gettime(_CLOCK_REALTIME, &ts) != 0 {
+			throw("clock_gettime")
+		}
+		ts.tv_sec += ns / 1e9
+		ts.tv_nsec += ns % 1e9
+		if ts.tv_nsec >= 1e9 {
+			ts.tv_sec++
+			ts.tv_nsec -= 1e9
+		}
+
+		if r, err := sem_timedwait((*semt)(unsafe.Pointer(_m_.waitsema)), &ts); r != 0 {
+			if err == _ETIMEDOUT || err == _EAGAIN || err == _EINTR {
+				return -1
+			}
+			println("sem_timedwait err ", err, " ts.tv_sec ", ts.tv_sec, " ts.tv_nsec ", ts.tv_nsec, " ns ", ns, " id ", _m_.id)
+			throw("sem_timedwait")
+		}
+		return 0
+	}
+	for {
+		r1, err := sem_wait((*semt)(unsafe.Pointer(_m_.waitsema)))
+		if r1 == 0 {
+			break
+		}
+		if err == _EINTR {
+			continue
+		}
+		throw("sem_wait")
+	}
+	return 0
+}
+
+//go:nosplit
+func semawakeup(mp *m) {
+	if sem_post((*semt)(unsafe.Pointer(mp.waitsema))) != 0 {
+		throw("sem_post")
+	}
+}
+
+func osinit() {
+	ncpu = int32(sysconf(__SC_NPROCESSORS_ONLN))
+	physPageSize = sysconf(__SC_PAGE_SIZE)
+}
+
+// Ms related functions
+func mpreinit(mp *m) {
+	mp.gsignal = malg(32 * 1024) // AIX wants >= 8K
+	mp.gsignal.m = mp
+}
+
+// errno address must be retrieved by calling _Errno libc function.
+// This will return a pointer to errno
+func miniterrno() {
+	mp := getg().m
+	r, _ := syscall0(&libc__Errno)
+	mp.perrno = r
+
+}
+
+func minit() {
+	miniterrno()
+	minitSignals()
+}
+
+func unminit() {
+	unminitSignals()
+}
+
+// tstart is a function descriptor to _tstart defined in assembly.
+var tstart funcDescriptor
+
+func newosproc(mp *m) {
+	var (
+		attr pthread_attr
+		oset sigset
+		tid  pthread
+	)
+
+	if pthread_attr_init(&attr) != 0 {
+		throw("pthread_attr_init")
+	}
+
+	if pthread_attr_setstacksize(&attr, threadStackSize) != 0 {
+		throw("pthread_attr_getstacksize")
+	}
+
+	if pthread_attr_setdetachstate(&attr, _PTHREAD_CREATE_DETACHED) != 0 {
+		throw("pthread_attr_setdetachstate")
+	}
+
+	// Disable signals during create, so that the new thread starts
+	// with signals disabled. It will enable them in minit.
+	sigprocmask(_SIG_SETMASK, &sigset_all, &oset)
+	var ret int32
+	for tries := 0; tries < 20; tries++ {
+		// pthread_create can fail with EAGAIN for no reasons
+		// but it will be ok if it retries.
+		ret = pthread_create(&tid, &attr, &tstart, unsafe.Pointer(mp))
+		if ret != _EAGAIN {
+			break
+		}
+		usleep(uint32(tries+1) * 1000) // Milliseconds.
+	}
+	sigprocmask(_SIG_SETMASK, &oset, nil)
+	if ret != 0 {
+		print("runtime: failed to create new OS thread (have ", mcount(), " already; errno=", ret, ")\n")
+		if ret == _EAGAIN {
+			println("runtime: may need to increase max user processes (ulimit -u)")
+		}
+		throw("newosproc")
+	}
+
+}
+
+func exitThread(wait *uint32) {
+	// We should never reach exitThread on AIX because we let
+	// libc clean up threads.
+	throw("exitThread")
+}
+
+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()
+}
+
+/* SIGNAL */
+
+const (
+	_NSIG = 256
+)
+
+// sigtramp is a function descriptor to _sigtramp defined in assembly
+var sigtramp funcDescriptor
+
+//go:nosplit
+//go:nowritebarrierrec
+func setsig(i uint32, fn uintptr) {
+	var sa sigactiont
+	sa.sa_flags = _SA_SIGINFO | _SA_ONSTACK | _SA_RESTART
+	sa.sa_mask = sigset_all
+	if fn == funcPC(sighandler) {
+		fn = uintptr(unsafe.Pointer(&sigtramp))
+	}
+	sa.sa_handler = fn
+	sigaction(uintptr(i), &sa, nil)
+
+}
+
+//go:nosplit
+//go:nowritebarrierrec
+func setsigstack(i uint32) {
+	throw("Not yet implemented\n")
+}
+
+//go:nosplit
+//go:nowritebarrierrec
+func getsig(i uint32) uintptr {
+	var sa sigactiont
+	sigaction(uintptr(i), nil, &sa)
+	return sa.sa_handler
+}
+
+// setSignaltstackSP sets the ss_sp field of a stackt.
+//go:nosplit
+func setSignalstackSP(s *stackt, sp uintptr) {
+	*(*uintptr)(unsafe.Pointer(&s.ss_sp)) = sp
+}
+
+func (c *sigctxt) fixsigcode(sig uint32) {
+}
+
+func sigaddset(mask *sigset, i int) {
+	(*mask)[(i-1)/64] |= 1 << ((uint32(i) - 1) & 63)
+}
+
+func sigdelset(mask *sigset, i int) {
+	(*mask)[(i-1)/64] &^= 1 << ((uint32(i) - 1) & 63)
+}
+
+const (
+	_CLOCK_REALTIME  = 9
+	_CLOCK_MONOTONIC = 10
+)
+
+//go:nosplit
+func nanotime() int64 {
+	tp := &timespec{}
+	if clock_gettime(_CLOCK_REALTIME, tp) != 0 {
+		throw("syscall clock_gettime failed")
+	}
+	return tp.tv_sec*1000000000 + tp.tv_nsec
+}
+
+func walltime() (sec int64, nsec int32) {
+	ts := &timespec{}
+	if clock_gettime(_CLOCK_REALTIME, ts) != 0 {
+		throw("syscall clock_gettime failed")
+	}
+	return ts.tv_sec, int32(ts.tv_nsec)
+}