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>

src/runtime/crash_unix_test.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly freebsd linux netbsd openbsd solaris
+// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
 
 package runtime_test
 

src/runtime/defs_aix.go

+// 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 ignore
+
+/*
+Input to cgo -godefs
+GOARCH=ppc64 go tool cgo -godefs defs_aix.go > defs_aix_ppc64_tmp.go
+
+This is only an helper to create defs_aix_ppc64.go
+Go runtime functions require the "linux" name of fields (ss_sp, si_addr, etc)
+However, AIX structures don't provide such names and must be modified.
+
+TODO(aix): create a script to automatise defs_aix creation.
+
+Modifications made:
+ - sigset replaced by a [4]uint64 array
+ - add sigset_all variable
+ - siginfo.si_addr uintptr instead of *byte
+ - add (*timeval) set_usec
+ - stackt.ss_sp uintptr instead of *byte
+ - stackt.ss_size uintptr instead of uint64
+ - sigcontext.sc_jmpbuf context64 instead of jumbuf
+ - ucontext.__extctx is a uintptr because we don't need extctx struct
+ - ucontext.uc_mcontext: replace jumbuf structure by context64 structure
+ - sigaction.sa_handler represents union field as both are uintptr
+ - tstate.* replace *byte by uintptr
+
+
+*/
+
+package runtime
+
+/*
+
+#include <sys/types.h>
+#include <sys/errno.h>
+#include <sys/time.h>
+#include <sys/signal.h>
+#include <sys/mman.h>
+#include <sys/thread.h>
+#include <sys/resource.h>
+
+#include <unistd.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <semaphore.h>
+*/
+import "C"
+
+const (
+	_EPERM     = C.EPERM
+	_ENOENT    = C.ENOENT
+	_EINTR     = C.EINTR
+	_EAGAIN    = C.EAGAIN
+	_ENOMEM    = C.ENOMEM
+	_EACCES    = C.EACCES
+	_EFAULT    = C.EFAULT
+	_EINVAL    = C.EINVAL
+	_ETIMEDOUT = C.ETIMEDOUT
+
+	_PROT_NONE  = C.PROT_NONE
+	_PROT_READ  = C.PROT_READ
+	_PROT_WRITE = C.PROT_WRITE
+	_PROT_EXEC  = C.PROT_EXEC
+
+	_MAP_ANONYMOUS = C.MAP_ANONYMOUS
+	_MAP_PRIVATE   = C.MAP_PRIVATE
+	_MAP_FIXED     = C.MAP_FIXED
+	_MADV_DONTNEED = C.MADV_DONTNEED
+
+	_SIGHUP     = C.SIGHUP
+	_SIGINT     = C.SIGINT
+	_SIGQUIT    = C.SIGQUIT
+	_SIGILL     = C.SIGILL
+	_SIGTRAP    = C.SIGTRAP
+	_SIGABRT    = C.SIGABRT
+	_SIGBUS     = C.SIGBUS
+	_SIGFPE     = C.SIGFPE
+	_SIGKILL    = C.SIGKILL
+	_SIGUSR1    = C.SIGUSR1
+	_SIGSEGV    = C.SIGSEGV
+	_SIGUSR2    = C.SIGUSR2
+	_SIGPIPE    = C.SIGPIPE
+	_SIGALRM    = C.SIGALRM
+	_SIGCHLD    = C.SIGCHLD
+	_SIGCONT    = C.SIGCONT
+	_SIGSTOP    = C.SIGSTOP
+	_SIGTSTP    = C.SIGTSTP
+	_SIGTTIN    = C.SIGTTIN
+	_SIGTTOU    = C.SIGTTOU
+	_SIGURG     = C.SIGURG
+	_SIGXCPU    = C.SIGXCPU
+	_SIGXFSZ    = C.SIGXFSZ
+	_SIGVTALRM  = C.SIGVTALRM
+	_SIGPROF    = C.SIGPROF
+	_SIGWINCH   = C.SIGWINCH
+	_SIGIO      = C.SIGIO
+	_SIGPWR     = C.SIGPWR
+	_SIGSYS     = C.SIGSYS
+	_SIGTERM    = C.SIGTERM
+	_SIGEMT     = C.SIGEMT
+	_SIGWAITING = C.SIGWAITING
+
+	_FPE_INTDIV = C.FPE_INTDIV
+	_FPE_INTOVF = C.FPE_INTOVF
+	_FPE_FLTDIV = C.FPE_FLTDIV
+	_FPE_FLTOVF = C.FPE_FLTOVF
+	_FPE_FLTUND = C.FPE_FLTUND
+	_FPE_FLTRES = C.FPE_FLTRES
+	_FPE_FLTINV = C.FPE_FLTINV
+	_FPE_FLTSUB = C.FPE_FLTSUB
+
+	_BUS_ADRALN = C.BUS_ADRALN
+	_BUS_ADRERR = C.BUS_ADRERR
+	_BUS_OBJERR = C.BUS_OBJERR
+
+	_SEGV_MAPERR = C.SEGV_MAPERR
+	_SEGV_ACCERR = C.SEGV_ACCERR
+
+	_ITIMER_REAL    = C.ITIMER_REAL
+	_ITIMER_VIRTUAL = C.ITIMER_VIRTUAL
+	_ITIMER_PROF    = C.ITIMER_PROF
+
+	_O_RDONLY = C.O_RDONLY
+
+	_SS_DISABLE  = C.SS_DISABLE
+	_SI_USER     = C.SI_USER
+	_SIG_BLOCK   = C.SIG_BLOCK
+	_SIG_UNBLOCK = C.SIG_UNBLOCK
+	_SIG_SETMASK = C.SIG_SETMASK
+
+	_SA_SIGINFO = C.SA_SIGINFO
+	_SA_RESTART = C.SA_RESTART
+	_SA_ONSTACK = C.SA_ONSTACK
+
+	_PTHREAD_CREATE_DETACHED = C.PTHREAD_CREATE_DETACHED
+
+	__SC_PAGE_SIZE        = C._SC_PAGE_SIZE
+	__SC_NPROCESSORS_ONLN = C._SC_NPROCESSORS_ONLN
+
+	_F_SETFD    = C.F_SETFD
+	_F_SETFL    = C.F_SETFL
+	_F_GETFD    = C.F_GETFD
+	_F_GETFL    = C.F_GETFL
+	_FD_CLOEXEC = C.FD_CLOEXEC
+)
+
+type sigset C.sigset_t
+type siginfo C.siginfo_t
+type timespec C.struct_timespec
+type timestruc C.struct_timestruc_t
+type timeval C.struct_timeval
+type itimerval C.struct_itimerval
+
+type stackt C.stack_t
+type sigcontext C.struct_sigcontext
+type ucontext C.ucontext_t
+type _Ctype_struct___extctx uint64 // ucontext use a pointer to this structure but it shouldn't be used
+type jmpbuf C.struct___jmpbuf
+type context64 C.struct___context64
+type sigactiont C.struct_sigaction
+type tstate C.struct_tstate
+type rusage C.struct_rusage
+
+type pthread C.pthread_t
+type pthread_attr C.pthread_attr_t
+
+type semt C.sem_t

src/runtime/defs_aix_ppc64.go

+// 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
+
+const (
+	_EPERM     = 0x1
+	_ENOENT    = 0x2
+	_EINTR     = 0x4
+	_EAGAIN    = 0xb
+	_ENOMEM    = 0xc
+	_EACCES    = 0xd
+	_EFAULT    = 0xe
+	_EINVAL    = 0x16
+	_ETIMEDOUT = 0x4e
+
+	_PROT_NONE  = 0x0
+	_PROT_READ  = 0x1
+	_PROT_WRITE = 0x2
+	_PROT_EXEC  = 0x4
+
+	_MAP_ANONYMOUS = 0x10
+	_MAP_PRIVATE   = 0x2
+	_MAP_FIXED     = 0x100
+	_MADV_DONTNEED = 0x4
+
+	_SIGHUP     = 0x1
+	_SIGINT     = 0x2
+	_SIGQUIT    = 0x3
+	_SIGILL     = 0x4
+	_SIGTRAP    = 0x5
+	_SIGABRT    = 0x6
+	_SIGBUS     = 0xa
+	_SIGFPE     = 0x8
+	_SIGKILL    = 0x9
+	_SIGUSR1    = 0x1e
+	_SIGSEGV    = 0xb
+	_SIGUSR2    = 0x1f
+	_SIGPIPE    = 0xd
+	_SIGALRM    = 0xe
+	_SIGCHLD    = 0x14
+	_SIGCONT    = 0x13
+	_SIGSTOP    = 0x11
+	_SIGTSTP    = 0x12
+	_SIGTTIN    = 0x15
+	_SIGTTOU    = 0x16
+	_SIGURG     = 0x10
+	_SIGXCPU    = 0x18
+	_SIGXFSZ    = 0x19
+	_SIGVTALRM  = 0x22
+	_SIGPROF    = 0x20
+	_SIGWINCH   = 0x1c
+	_SIGIO      = 0x17
+	_SIGPWR     = 0x1d
+	_SIGSYS     = 0xc
+	_SIGTERM    = 0xf
+	_SIGEMT     = 0x7
+	_SIGWAITING = 0x27
+
+	_FPE_INTDIV = 0x14
+	_FPE_INTOVF = 0x15
+	_FPE_FLTDIV = 0x16
+	_FPE_FLTOVF = 0x17
+	_FPE_FLTUND = 0x18
+	_FPE_FLTRES = 0x19
+	_FPE_FLTINV = 0x1a
+	_FPE_FLTSUB = 0x1b
+
+	_BUS_ADRALN = 0x1
+	_BUS_ADRERR = 0x2
+	_BUS_OBJERR = 0x3
+	_
+	_SEGV_MAPERR = 0x32
+	_SEGV_ACCERR = 0x33
+
+	_ITIMER_REAL    = 0x0
+	_ITIMER_VIRTUAL = 0x1
+	_ITIMER_PROF    = 0x2
+
+	_O_RDONLY = 0x0
+
+	_SS_DISABLE  = 0x2
+	_SI_USER     = 0x0
+	_SIG_BLOCK   = 0x0
+	_SIG_UNBLOCK = 0x1
+	_SIG_SETMASK = 0x2
+
+	_SA_SIGINFO = 0x100
+	_SA_RESTART = 0x8
+	_SA_ONSTACK = 0x1
+
+	_PTHREAD_CREATE_DETACHED = 0x1
+
+	__SC_PAGE_SIZE        = 0x30
+	__SC_NPROCESSORS_ONLN = 0x48
+
+	_F_SETFD    = 0x2
+	_F_SETFL    = 0x4
+	_F_GETFD    = 0x1
+	_F_GETFL    = 0x3
+	_FD_CLOEXEC = 0x1
+)
+
+type sigset [4]uint64
+
+var sigset_all = sigset{^uint64(0), ^uint64(0), ^uint64(0), ^uint64(0)}
+
+type siginfo struct {
+	si_signo   int32
+	si_errno   int32
+	si_code    int32
+	si_pid     int32
+	si_uid     uint32
+	si_status  int32
+	si_addr    uintptr
+	si_band    int64
+	si_value   [2]int32 // [8]byte
+	__si_flags int32
+	__pad      [3]int32
+}
+
+type timespec struct {
+	tv_sec  int64
+	tv_nsec int64
+}
+type timeval struct {
+	tv_sec    int64
+	tv_usec   int32
+	pad_cgo_0 [4]byte
+}
+
+func (tv *timeval) set_usec(x int32) {
+	tv.tv_usec = x
+}
+
+type itimerval struct {
+	it_interval timeval
+	it_value    timeval
+}
+
+type stackt struct {
+	ss_sp     uintptr
+	ss_size   uintptr
+	ss_flags  int32
+	__pad     [4]int32
+	pas_cgo_0 [4]byte
+}
+
+type sigcontext struct {
+	sc_onstack int32
+	pad_cgo_0  [4]byte
+	sc_mask    sigset
+	sc_uerror  int32
+	sc_jmpbuf  context64
+}
+
+type ucontext struct {
+	__sc_onstack   int32
+	pad_cgo_0      [4]byte
+	uc_sigmask     sigset
+	__sc_error     int32
+	pad_cgo_1      [4]byte
+	uc_mcontext    context64
+	uc_link        *ucontext
+	uc_stack       stackt
+	__extctx       uintptr // pointer to struct __extctx but we don't use it
+	__extctx_magic int32
+	__pad          int32
+}
+
+type context64 struct {
+	gpr        [32]uint64
+	msr        uint64
+	iar        uint64
+	lr         uint64
+	ctr        uint64
+	cr         uint32
+	xer        uint32
+	fpscr      uint32
+	fpscrx     uint32
+	except     [1]uint64
+	fpr        [32]float64
+	fpeu       uint8
+	fpinfo     uint8
+	fpscr24_31 uint8
+	pad        [1]uint8
+	excp_type  int32
+}
+
+type sigactiont struct {
+	sa_handler uintptr // a union of two pointer
+	sa_mask    sigset
+	sa_flags   int32
+	pad_cgo_0  [4]byte
+}
+
+type pthread uint32
+type pthread_attr *byte
+
+type semt int32

src/runtime/env_posix.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly freebsd js,wasm linux nacl netbsd openbsd solaris windows
+// +build aix darwin dragonfly freebsd js,wasm linux nacl netbsd openbsd solaris windows
 
 package runtime
 

src/runtime/export_unix_test.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly freebsd linux netbsd openbsd solaris
+// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
 
 package runtime
 

src/runtime/lock_sema.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin nacl netbsd openbsd plan9 solaris windows
+// +build aix darwin nacl netbsd openbsd plan9 solaris windows
 
 package runtime
 

src/runtime/mem_aix.go

+// 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.
+
+package runtime
+
+import (
+	"unsafe"
+)
+
+// Don't split the stack as this method may be invoked without a valid G, which
+// prevents us from allocating more stack.
+//go:nosplit
+func sysAlloc(n uintptr, sysStat *uint64) unsafe.Pointer {
+	p, err := mmap(nil, n, _PROT_READ|_PROT_WRITE, _MAP_ANONYMOUS|_MAP_PRIVATE, -1, 0)
+	if err != 0 {
+		if err == _EACCES {
+			print("runtime: mmap: access denied\n")
+			exit(2)
+		}
+		if err == _EAGAIN {
+			print("runtime: mmap: too much locked memory (check 'ulimit -l').\n")
+			exit(2)
+		}
+		//println("sysAlloc failed: ", err)
+		return nil
+	}
+	mSysStatInc(sysStat, n)
+	return p
+}
+
+func sysUnused(v unsafe.Pointer, n uintptr) {
+	madvise(v, n, _MADV_DONTNEED)
+}
+
+func sysUsed(v unsafe.Pointer, n uintptr) {
+}
+
+// Don't split the stack as this function may be invoked without a valid G,
+// which prevents us from allocating more stack.
+//go:nosplit
+func sysFree(v unsafe.Pointer, n uintptr, sysStat *uint64) {
+	mSysStatDec(sysStat, n)
+	munmap(v, n)
+
+}
+
+func sysFault(v unsafe.Pointer, n uintptr) {
+	mmap(v, n, _PROT_NONE, _MAP_ANONYMOUS|_MAP_PRIVATE|_MAP_FIXED, -1, 0)
+}
+
+func sysReserve(v unsafe.Pointer, n uintptr) unsafe.Pointer {
+	p, err := mmap(v, n, _PROT_NONE, _MAP_ANONYMOUS|_MAP_PRIVATE, -1, 0)
+	if err != 0 {
+		return nil
+	}
+	return p
+}
+
+func sysMap(v unsafe.Pointer, n uintptr, sysStat *uint64) {
+	mSysStatInc(sysStat, n)
+
+	// AIX does not allow mapping a range that is already mapped.
+	// So always unmap first even if it is already unmapped.
+	munmap(v, n)
+	p, err := mmap(v, n, _PROT_READ|_PROT_WRITE, _MAP_ANONYMOUS|_MAP_FIXED|_MAP_PRIVATE, -1, 0)
+
+	if err == _ENOMEM {
+		throw("runtime: out of memory")
+	}
+	if p != v || err != 0 {
+		throw("runtime: cannot map pages in arena address space")
+	}
+}

src/runtime/mmap.go

@@ -10,6 +10,7 @@
 // +build !linux !arm64
 // +build !js
 // +build !darwin
+// +build !aix
 
 package runtime
 

src/runtime/netpoll.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly freebsd js,wasm linux nacl netbsd openbsd solaris windows
+// +build aix darwin dragonfly freebsd js,wasm linux nacl netbsd openbsd solaris windows
 
 package runtime
 
@@ -166,8 +166,8 @@ func poll_runtime_pollWait(pd *pollDesc, mode int) int {
 	if err != 0 {
 		return err
 	}
-	// As for now only Solaris uses level-triggered IO.
-	if GOOS == "solaris" {
+	// As for now only Solaris and AIX use level-triggered IO.
+	if GOOS == "solaris" || GOOS == "aix" {
 		netpollarm(pd, mode)
 	}
 	for !netpollblock(pd, int32(mode), false) {

src/runtime/netpoll_aix.go

+// 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.
+
+package runtime
+
+import "unsafe"
+
+// 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
+
+//go:cgo_import_dynamic libc_poll poll "libc.a/shr_64.o"
+//go:linkname libc_poll libc_poll
+
+var libc_poll libFunc
+
+//go:nosplit
+func poll(pfds *pollfd, npfds uintptr, timeout uintptr) (int32, int32) {
+	r, err := syscall3(&libc_poll, uintptr(unsafe.Pointer(pfds)), npfds, timeout)
+	return int32(r), int32(err)
+}
+
+//go:nosplit
+func fcntl(fd, cmd int32, arg uintptr) int32 {
+	r, _ := syscall3(&libc_fcntl, uintptr(fd), uintptr(cmd), arg)
+	return int32(r)
+}
+
+// pollfd represents the poll structure for AIX operating system.
+type pollfd struct {
+	fd      int32
+	events  int16
+	revents int16
+}
+
+const _POLLIN = 0x0001
+const _POLLOUT = 0x0002
+const _POLLHUP = 0x2000
+const _POLLERR = 0x4000
+const _O_NONBLOCK = 0x4
+
+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 := pipe(&p[0]); err < 0 {
+		throw("netpollinit: failed to create pipe")
+	}
+	rdwake = p[0]
+	wrwake = p[1]
+
+	fl := uintptr(fcntl(rdwake, _F_GETFL, 0))
+	fcntl(rdwake, _F_SETFL, fl|_O_NONBLOCK)
+	fcntl(rdwake, _F_SETFD, _FD_CLOEXEC)
+
+	fl = uintptr(fcntl(wrwake, _F_GETFL, 0))
+	fcntl(wrwake, _F_SETFL, fl|_O_NONBLOCK)
+	fcntl(wrwake, _F_SETFD, _FD_CLOEXEC)
+
+	// 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 = rdwake
+	pfds[0].events = _POLLIN
+
+	pds = make([]*pollDesc, 1, 128)
+	pds[0] = nil
+}
+
+func netpolldescriptor() uintptr {
+	// Both fd 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)
+}
+
+//go:nowritebarrierrec
+func netpoll(block bool) gList {
+	timeout := ^uintptr(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, e := poll(&pfds[0], uintptr(len(pfds)), timeout)
+	if pollVerbose {
+		println("*** netpoll after poll", n)
+	}
+	if n < 0 {
+		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
+}

src/runtime/os_aix.go

+// 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)
+}

src/runtime/proc.go

@@ -1172,8 +1172,8 @@ func mstart() {
 	mstart1()
 
 	// Exit this thread.
-	if GOOS == "windows" || GOOS == "solaris" || GOOS == "plan9" || GOOS == "darwin" {
-		// Window, Solaris, Darwin and Plan 9 always system-allocate
+	if GOOS == "windows" || GOOS == "solaris" || GOOS == "plan9" || GOOS == "darwin" || GOOS == "aix" {
+		// Window, Solaris, Darwin, AIX and Plan 9 always system-allocate
 		// the stack, but put it in _g_.stack before mstart,
 		// so the logic above hasn't set osStack yet.
 		osStack = true

src/runtime/rt0_aix_ppc64.s

+// 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.
+
+#include "textflag.h"
+
+// _rt0_ppc64_aix is a function descriptor of the entrypoint function
+// __start. This name is needed by cmd/link.
+DATA	_rt0_ppc64_aix+0(SB)/8, $__start<>(SB)
+DATA	_rt0_ppc64_aix+8(SB)/8, $TOC(SB)
+GLOBL	_rt0_ppc64_aix(SB), NOPTR, $16
+
+
+// The starting function must return in the loader to
+// initialise some librairies, especially libthread which
+// creates the main thread and adds the TLS in R13
+// R19 contains a function descriptor to the loader function
+// which needs to be called.
+// This code is similar to the __start function in C
+TEXT __start<>(SB),NOSPLIT,$-8
+	XOR R0, R0
+	MOVD $libc___n_pthreads(SB), R4
+	MOVD 0(R4), R4
+	MOVD $libc___mod_init(SB), R5
+	MOVD 0(R5), R5
+	MOVD 0(R19), R0
+	MOVD R2, 40(R1)
+	MOVD 8(R19), R2
+	MOVD R18, R3
+	MOVD R0, CTR
+	BL (CTR) // Return to AIX loader
+
+	// Launch rt0_go
+	MOVD 40(R1), R2
+	MOVD R14, R3 // argc
+	MOVD R15, R4 // argv
+	MOVD $runtime·rt0_go(SB), R12
+	MOVD R12, CTR
+	BR (CTR)
+

src/runtime/runtime_unix_test.go

@@ -6,7 +6,7 @@
 // We need a fast system call to provoke the race,
 // and Close(-1) is nearly universally fast.
 
-// +build darwin dragonfly freebsd linux netbsd openbsd plan9
+// +build aix darwin dragonfly freebsd linux netbsd openbsd plan9
 
 package runtime_test
 

src/runtime/signal_aix_ppc64.go

+/// 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 (
+	"runtime/internal/sys"
+	"unsafe"
+)
+
+type sigctxt struct {
+	info *siginfo
+	ctxt unsafe.Pointer
+}
+
+//go:nosplit
+//go:nowritebarrierrec
+func (c *sigctxt) regs() *context64 { return &(*ucontext)(c.ctxt).uc_mcontext }
+
+func (c *sigctxt) r0() uint64  { return c.regs().gpr[0] }
+func (c *sigctxt) r1() uint64  { return c.regs().gpr[1] }
+func (c *sigctxt) r2() uint64  { return c.regs().gpr[2] }
+func (c *sigctxt) r3() uint64  { return c.regs().gpr[3] }
+func (c *sigctxt) r4() uint64  { return c.regs().gpr[4] }
+func (c *sigctxt) r5() uint64  { return c.regs().gpr[5] }
+func (c *sigctxt) r6() uint64  { return c.regs().gpr[6] }
+func (c *sigctxt) r7() uint64  { return c.regs().gpr[7] }
+func (c *sigctxt) r8() uint64  { return c.regs().gpr[8] }
+func (c *sigctxt) r9() uint64  { return c.regs().gpr[9] }
+func (c *sigctxt) r10() uint64 { return c.regs().gpr[10] }
+func (c *sigctxt) r11() uint64 { return c.regs().gpr[11] }
+func (c *sigctxt) r12() uint64 { return c.regs().gpr[12] }
+func (c *sigctxt) r13() uint64 { return c.regs().gpr[13] }
+func (c *sigctxt) r14() uint64 { return c.regs().gpr[14] }
+func (c *sigctxt) r15() uint64 { return c.regs().gpr[15] }
+func (c *sigctxt) r16() uint64 { return c.regs().gpr[16] }
+func (c *sigctxt) r17() uint64 { return c.regs().gpr[17] }
+func (c *sigctxt) r18() uint64 { return c.regs().gpr[18] }
+func (c *sigctxt) r19() uint64 { return c.regs().gpr[19] }
+func (c *sigctxt) r20() uint64 { return c.regs().gpr[20] }
+func (c *sigctxt) r21() uint64 { return c.regs().gpr[21] }
+func (c *sigctxt) r22() uint64 { return c.regs().gpr[22] }
+func (c *sigctxt) r23() uint64 { return c.regs().gpr[23] }
+func (c *sigctxt) r24() uint64 { return c.regs().gpr[24] }
+func (c *sigctxt) r25() uint64 { return c.regs().gpr[25] }
+func (c *sigctxt) r26() uint64 { return c.regs().gpr[26] }
+func (c *sigctxt) r27() uint64 { return c.regs().gpr[27] }
+func (c *sigctxt) r28() uint64 { return c.regs().gpr[28] }
+func (c *sigctxt) r29() uint64 { return c.regs().gpr[29] }
+func (c *sigctxt) r30() uint64 { return c.regs().gpr[30] }
+func (c *sigctxt) r31() uint64 { return c.regs().gpr[31] }
+func (c *sigctxt) sp() uint64  { return c.regs().gpr[1] }
+
+//go:nosplit
+//go:nowritebarrierrec
+func (c *sigctxt) pc() uint64 { return c.regs().iar }
+
+func (c *sigctxt) ctr() uint64    { return c.regs().ctr }
+func (c *sigctxt) link() uint64   { return c.regs().lr }
+func (c *sigctxt) xer() uint32    { return c.regs().xer }
+func (c *sigctxt) ccr() uint32    { return c.regs().cr }
+func (c *sigctxt) fpscr() uint32  { return c.regs().fpscr }
+func (c *sigctxt) fpscrx() uint32 { return c.regs().fpscrx }
+
+// TODO(aix): find trap equivalent
+func (c *sigctxt) trap() uint32 { return 0x0 }
+
+func (c *sigctxt) sigcode() uint32 { return uint32(c.info.si_code) }
+func (c *sigctxt) sigaddr() uint64 { return uint64(c.info.si_addr) }
+func (c *sigctxt) fault() uintptr  { return uintptr(c.sigaddr()) }
+
+func (c *sigctxt) set_r0(x uint64)   { c.regs().gpr[0] = x }
+func (c *sigctxt) set_r12(x uint64)  { c.regs().gpr[12] = x }
+func (c *sigctxt) set_r30(x uint64)  { c.regs().gpr[30] = x }
+func (c *sigctxt) set_pc(x uint64)   { c.regs().iar = x }
+func (c *sigctxt) set_sp(x uint64)   { c.regs().gpr[1] = x }
+func (c *sigctxt) set_link(x uint64) { c.regs().lr = x }
+
+func (c *sigctxt) set_sigcode(x uint32) { c.info.si_code = int32(x) }
+func (c *sigctxt) set_sigaddr(x uint64) {
+	*(*uintptr)(add(unsafe.Pointer(c.info), 2*sys.PtrSize)) = uintptr(x)
+}

src/runtime/signal_ppc64x.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build linux
+// +build aix linux
 // +build ppc64 ppc64le
 
 package runtime

src/runtime/signal_sighandler.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly freebsd linux nacl netbsd openbsd solaris
+// +build aix darwin dragonfly freebsd linux nacl netbsd openbsd solaris
 
 package runtime
 

src/runtime/signal_unix.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly freebsd linux netbsd openbsd solaris
+// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
 
 package runtime
 

src/runtime/stubs2.go

@@ -8,6 +8,7 @@
 // +build !nacl
 // +build !js
 // +build !darwin
+// +build !aix
 
 package runtime
 

src/runtime/stubs3.go

@@ -8,6 +8,7 @@
 // +build !nacl
 // +build !freebsd
 // +build !darwin
+// +build !aix
 
 package runtime
 

src/runtime/sys_aix_ppc64.s

+// 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
+// +build ppc64 ppc64le
+
+//
+// System calls and other sys.stuff for ppc64, Aix
+//
+
+#include "go_asm.h"
+#include "go_tls.h"
+#include "textflag.h"
+#include "asm_ppc64x.h"
+
+// This function calls a C function with the function descriptor in R12
+TEXT runtime·callCfunction(SB),	NOSPLIT|NOFRAME,$0
+	MOVD	0(R12), R12
+	MOVD	R2, 40(R1)
+	MOVD	0(R12), R0
+	MOVD	8(R12), R2
+	MOVD	R0, CTR
+	BR	(CTR)
+
+
+// asmsyscall6 calls a library function with a function descriptor
+// stored in libcall_fn and store the results in libcall struture
+// Up to 6 arguments can be passed to this C function
+// Called by runtime.asmcgocall
+// It reserves a stack of 288 bytes for the C function.
+// NOT USING GO CALLING CONVENTION
+TEXT runtime·asmsyscall6(SB),NOSPLIT,$256
+	MOVD	R3, 48(R1) // Save libcall for later
+	MOVD	libcall_fn(R3), R12
+	MOVD	libcall_args(R3), R9
+	MOVD	0(R9), R3
+	MOVD	8(R9), R4
+	MOVD	16(R9), R5
+	MOVD	24(R9), R6
+	MOVD	32(R9), R7
+	MOVD	40(R9), R8
+	BL	runtime·callCfunction(SB)
+
+	// Restore R0 and TOC
+	XOR	R0, R0
+	MOVD	40(R1), R2
+
+	// Store result in libcall
+	MOVD	48(R1), R5
+	MOVD	R3, (libcall_r1)(R5)
+	MOVD	$-1, R6
+	CMP	R6, R3
+	BNE	skiperrno
+
+    // Save errno in libcall
+	BL	runtime·load_g(SB)
+	MOVD	g_m(g), R4
+	MOVD	(m_mOS + mOS_perrno)(R4), R9
+	MOVW	0(R9), R9
+	MOVD	R9, (libcall_err)(R5)
+	RET
+skiperrno:
+	// Reset errno if no error has been returned
+	MOVD	R0, (libcall_err)(R5)
+	RET
+
+
+TEXT runtime·sigfwd(SB),NOSPLIT,$0-32
+	MOVW	sig+8(FP), R3
+	MOVD	info+16(FP), R4
+	MOVD	ctx+24(FP), R5
+	MOVD	fn+0(FP), R12
+	MOVD	R12, CTR
+	BL	(CTR)
+	RET
+
+
+// runtime.sigtramp is a function descriptor to the real sigtramp.
+DATA	runtime·sigtramp+0(SB)/8, $runtime·_sigtramp(SB)
+DATA	runtime·sigtramp+8(SB)/8, $TOC(SB)
+DATA	runtime·sigtramp+16(SB)/8, $0
+GLOBL	runtime·sigtramp(SB), NOPTR, $24
+
+// This funcion must not have any frame as we want to control how
+// every registers are used.
+TEXT runtime·_sigtramp(SB),NOSPLIT|NOFRAME,$0
+	MOVD	LR, R0
+	MOVD	R0, 16(R1)
+	// initialize essential registers (just in case)
+	BL	runtime·reginit(SB)
+
+	// Note that we are executing on altsigstack here, so we have
+	// more stack available than NOSPLIT would have us believe.
+	// To defeat the linker, we make our own stack frame with
+	// more space.
+	SUB	   $128+FIXED_FRAME, R1
+
+	// Save registers
+	MOVD	R31, 56(R1)
+	MOVD	g, 64(R1)
+	MOVD	R29, 72(R1)
+
+	BL	runtime·load_g(SB)
+
+	// Save m->libcall. We need to do this because we
+	// might get interrupted by a signal in runtime·asmcgocall.
+
+	// save m->libcall
+	MOVD	g_m(g), R6
+	MOVD	(m_libcall+libcall_fn)(R6), R7
+	MOVD	R7, 80(R1)
+	MOVD	(m_libcall+libcall_args)(R6), R7
+	MOVD	R7, 88(R1)
+	MOVD	(m_libcall+libcall_n)(R6), R7
+	MOVD	R7, 96(R1)
+	MOVD	(m_libcall+libcall_r1)(R6), R7
+	MOVD	R7, 104(R1)
+	MOVD	(m_libcall+libcall_r2)(R6), R7
+	MOVD	R7, 112(R1)
+
+	// save errno, it might be EINTR; stuff we do here might reset it.
+	MOVD	(m_mOS+mOS_perrno)(R6), R8
+	MOVD	0(R8), R8
+	MOVD	R8, 120(R1)
+
+	MOVW	R3, FIXED_FRAME+0(R1)
+	MOVD	R4, FIXED_FRAME+8(R1)
+	MOVD	R5, FIXED_FRAME+16(R1)
+	MOVD	$runtime·sigtrampgo(SB), R12
+	MOVD	R12, CTR
+	BL	(CTR)
+
+	MOVD	g_m(g), R6
+	// restore libcall
+	MOVD	80(R1), R7
+	MOVD	R7, (m_libcall+libcall_fn)(R6)
+	MOVD	88(R1), R7
+	MOVD	R7, (m_libcall+libcall_args)(R6)
+	MOVD	96(R1), R7
+	MOVD	R7, (m_libcall+libcall_n)(R6)
+	MOVD	104(R1), R7
+	MOVD	R7, (m_libcall+libcall_r1)(R6)
+	MOVD	112(R1), R7
+	MOVD	R7, (m_libcall+libcall_r2)(R6)
+
+	// restore errno
+	MOVD	(m_mOS+mOS_perrno)(R6), R7
+	MOVD	120(R1), R8
+	MOVD	R8, 0(R7)
+
+	// restore registers
+	MOVD	56(R1),R31
+	MOVD	64(R1),g
+	MOVD	72(R1),R29
+
+	// Don't use RET because we need to restore R31 !
+	ADD $128+FIXED_FRAME, R1
+	MOVD	16(R1), R0
+	MOVD	R0, LR
+	BR (LR)
+
+// runtime.tstart is a function descriptor to the real tstart.
+DATA	runtime·tstart+0(SB)/8, $runtime·_tstart(SB)
+DATA	runtime·tstart+8(SB)/8, $TOC(SB)
+DATA	runtime·tstart+16(SB)/8, $0
+GLOBL	runtime·tstart(SB), NOPTR, $24
+
+TEXT runtime·_tstart(SB),NOSPLIT,$0
+	XOR	 R0, R0 // reset R0
+
+	// set g
+	MOVD	m_g0(R3), g
+	BL	runtime·save_g(SB)
+	MOVD	R3, g_m(g)
+
+	// Layout new m scheduler stack on os stack.
+	MOVD	R1, R3
+	MOVD	R3, (g_stack+stack_hi)(g)
+	SUB	$(const_threadStackSize), R3		// stack size
+	MOVD	R3, (g_stack+stack_lo)(g)
+	ADD	$const__StackGuard, R3
+	MOVD	R3, g_stackguard0(g)
+	MOVD	R3, g_stackguard1(g)
+
+	BL	runtime·mstart(SB)
+
+	MOVD R0, R3
+	RET
+
+// Runs on OS stack, called from runtime·osyield.
+TEXT runtime·osyield1(SB),NOSPLIT,$0
+	MOVD	$libc_sched_yield(SB), R12
+	MOVD	0(R12), R12
+	MOVD	R2, 40(R1)
+	MOVD	0(R12), R0
+	MOVD	8(R12), R2
+	MOVD	R0, CTR
+	BL	(CTR)
+	MOVD	40(R1), R2
+	RET

src/runtime/timestub2.go

@@ -5,6 +5,7 @@
 // +build !darwin
 // +build !windows
 // +build !freebsd
+// +build !aix
 
 package runtime