runtime: switch runtime to libc for openbsd/amd64

Use libc rather than performing direct system calls for the runtime on
openbsd/amd64.

Updates #36435

Change-Id: Ib708009c3743f56a3fd6cb3bc731451e4a398849
Reviewed-on: https://go-review.googlesource.com/c/go/+/270379
Trust: Joel Sing <joel@sing.id.au>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

12 files changed, 641 insertions, 343 deletions

diff --git a/src/runtime/defs_openbsd.go b/src/runtime/defs_openbsd.go
index 57717abf7e..ff7e21c71e 100644
--- a/src/runtime/defs_openbsd.go
+++ b/src/runtime/defs_openbsd.go
@@ -56,6 +56,11 @@ const (
 
 	PTHREAD_CREATE_DETACHED = C.PTHREAD_CREATE_DETACHED
 
+	F_SETFD    = C.F_SETFD
+	F_GETFL    = C.F_GETFL
+	F_SETFL    = C.F_SETFL
+	FD_CLOEXEC = C.FD_CLOEXEC
+
 	SIGHUP    = C.SIGHUP
 	SIGINT    = C.SIGINT
 	SIGQUIT   = C.SIGQUIT
diff --git a/src/runtime/defs_openbsd_amd64.go b/src/runtime/defs_openbsd_amd64.go
index 01ca934cea..46f1245201 100644
--- a/src/runtime/defs_openbsd_amd64.go
+++ b/src/runtime/defs_openbsd_amd64.go
@@ -32,6 +32,11 @@ const (
 
 	_PTHREAD_CREATE_DETACHED = 0x1
 
+	_F_SETFD    = 0x2
+	_F_GETFL    = 0x3
+	_F_SETFL    = 0x4
+	_FD_CLOEXEC = 0x1
+
 	_SIGHUP    = 0x1
 	_SIGINT    = 0x2
 	_SIGQUIT   = 0x3
diff --git a/src/runtime/mmap.go b/src/runtime/mmap.go
index 9fe31cb416..1b1848b79e 100644
--- a/src/runtime/mmap.go
+++ b/src/runtime/mmap.go
@@ -2,14 +2,15 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build !aix
+// +build !darwin
+// +build !js
+// +build !linux !amd64
+// +build !linux !arm64
+// +build !openbsd
 // +build !plan9
 // +build !solaris
 // +build !windows
-// +build !linux !amd64
-// +build !linux !arm64
-// +build !js
-// +build !darwin
-// +build !aix
 
 package runtime
 
diff --git a/src/runtime/os_openbsd.go b/src/runtime/os_openbsd.go
index 56b686a2fa..6259b96c22 100644
--- a/src/runtime/os_openbsd.go
+++ b/src/runtime/os_openbsd.go
@@ -13,49 +13,6 @@ type mOS struct {
 	waitsemacount uint32
 }
 
-//go:noescape
-func setitimer(mode int32, new, old *itimerval)
-
-//go:noescape
-func sigaction(sig uint32, new, old *sigactiont)
-
-//go:noescape
-func sigaltstack(new, old *stackt)
-
-//go:noescape
-func obsdsigprocmask(how int32, new sigset) sigset
-
-//go:nosplit
-//go:nowritebarrierrec
-func sigprocmask(how int32, new, old *sigset) {
-	n := sigset(0)
-	if new != nil {
-		n = *new
-	}
-	r := obsdsigprocmask(how, n)
-	if old != nil {
-		*old = r
-	}
-}
-
-//go:noescape
-func sysctl(mib *uint32, miblen uint32, out *byte, size *uintptr, dst *byte, ndst uintptr) int32
-
-func raiseproc(sig uint32)
-
-func getthrid() int32
-func thrkill(tid int32, sig int)
-
-func kqueue() int32
-
-//go:noescape
-func kevent(kq int32, ch *keventt, nch int32, ev *keventt, nev int32, ts *timespec) int32
-
-func pipe() (r, w int32, errno int32)
-func pipe2(flags int32) (r, w int32, errno int32)
-func closeonexec(fd int32)
-func setNonblock(fd int32)
-
 const (
 	_ESRCH       = 3
 	_EWOULDBLOCK = _EAGAIN
diff --git a/src/runtime/os_openbsd_syscall2.go b/src/runtime/os_openbsd_syscall2.go
new file mode 100644
index 0000000000..74eb271c2c
--- /dev/null
+++ b/src/runtime/os_openbsd_syscall2.go
@@ -0,0 +1,95 @@
+// Copyright 2020 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 openbsd,!amd64
+
+package runtime
+
+import (
+	"unsafe"
+)
+
+//go:noescape
+func sigaction(sig uint32, new, old *sigactiont)
+
+func kqueue() int32
+
+//go:noescape
+func kevent(kq int32, ch *keventt, nch int32, ev *keventt, nev int32, ts *timespec) int32
+
+func raiseproc(sig uint32)
+
+func getthrid() int32
+func thrkill(tid int32, sig int)
+
+// read calls the read system call.
+// It returns a non-negative number of bytes written or a negative errno value.
+func read(fd int32, p unsafe.Pointer, n int32) int32
+
+func closefd(fd int32) int32
+
+func exit(code int32)
+func usleep(usec uint32)
+
+// write calls the write system call.
+// It returns a non-negative number of bytes written or a negative errno value.
+//go:noescape
+func write1(fd uintptr, p unsafe.Pointer, n int32) int32
+
+//go:noescape
+func open(name *byte, mode, perm int32) int32
+
+// return value is only set on linux to be used in osinit()
+func madvise(addr unsafe.Pointer, n uintptr, flags int32) int32
+
+// exitThread terminates the current thread, writing *wait = 0 when
+// the stack is safe to reclaim.
+//
+//go:noescape
+func exitThread(wait *uint32)
+
+//go:noescape
+func obsdsigprocmask(how int32, new sigset) sigset
+
+//go:nosplit
+//go:nowritebarrierrec
+func sigprocmask(how int32, new, old *sigset) {
+	n := sigset(0)
+	if new != nil {
+		n = *new
+	}
+	r := obsdsigprocmask(how, n)
+	if old != nil {
+		*old = r
+	}
+}
+
+func pipe() (r, w int32, errno int32)
+func pipe2(flags int32) (r, w int32, errno int32)
+
+//go:noescape
+func setitimer(mode int32, new, old *itimerval)
+
+//go:noescape
+func sysctl(mib *uint32, miblen uint32, out *byte, size *uintptr, dst *byte, ndst uintptr) int32
+
+// mmap calls the mmap system call. It is implemented in assembly.
+// We only pass the lower 32 bits of file offset to the
+// assembly routine; the higher bits (if required), should be provided
+// by the assembly routine as 0.
+// The err result is an OS error code such as ENOMEM.
+func mmap(addr unsafe.Pointer, n uintptr, prot, flags, fd int32, off uint32) (p unsafe.Pointer, err int)
+
+// munmap calls the munmap system call. It is implemented in assembly.
+func munmap(addr unsafe.Pointer, n uintptr)
+
+func nanotime1() int64
+
+//go:noescape
+func sigaltstack(new, old *stackt)
+
+func closeonexec(fd int32)
+func setNonblock(fd int32)
+
+func walltime1() (sec int64, nsec int32)
diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index 30033712aa..aa44c625c5 100644
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -1212,6 +1212,8 @@ func usesLibcall() bool {
 	switch GOOS {
 	case "aix", "darwin", "illumos", "ios", "solaris", "windows":
 		return true
+	case "openbsd":
+		return GOARCH == "amd64"
 	}
 	return false
 }
diff --git a/src/runtime/signal_openbsd.go b/src/runtime/signal_openbsd.go
index 99c601ce58..d2c5c5e39a 100644
--- a/src/runtime/signal_openbsd.go
+++ b/src/runtime/signal_openbsd.go
@@ -37,5 +37,5 @@ var sigtable = [...]sigTabT{
 	/* 29 */ {_SigNotify, "SIGINFO: status request from keyboard"},
 	/* 30 */ {_SigNotify, "SIGUSR1: user-defined signal 1"},
 	/* 31 */ {_SigNotify, "SIGUSR2: user-defined signal 2"},
-	/* 32 */ {_SigNotify, "SIGTHR: reserved"},
+	/* 32 */ {0, "SIGTHR: reserved"}, // thread AST - cannot be registered.
 }
diff --git a/src/runtime/stubs2.go b/src/runtime/stubs2.go
index 4a1a5cc3d9..85088b3ab9 100644
--- a/src/runtime/stubs2.go
+++ b/src/runtime/stubs2.go
@@ -2,12 +2,13 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build !aix
+// +build !darwin
+// +build !js
+// +build !openbsd
 // +build !plan9
 // +build !solaris
 // +build !windows
-// +build !js
-// +build !darwin
-// +build !aix
 
 package runtime
 
diff --git a/src/runtime/stubs3.go b/src/runtime/stubs3.go
index 95eecc7eca..1885d32051 100644
--- a/src/runtime/stubs3.go
+++ b/src/runtime/stubs3.go
@@ -2,11 +2,12 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build !aix
+// +build !darwin
+// +build !freebsd
+// +build !openbsd
 // +build !plan9
 // +build !solaris
-// +build !freebsd
-// +build !darwin
-// +build !aix
 
 package runtime
 
diff --git a/src/runtime/sys_openbsd2.go b/src/runtime/sys_openbsd2.go
new file mode 100644
index 0000000000..73592df226
--- /dev/null
+++ b/src/runtime/sys_openbsd2.go
@@ -0,0 +1,250 @@
+// Copyright 2020 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 openbsd,amd64
+
+package runtime
+
+import "unsafe"
+
+// This is exported via linkname to assembly in runtime/cgo.
+//go:linkname exit
+//go:nosplit
+//go:cgo_unsafe_args
+func exit(code int32) {
+	libcCall(unsafe.Pointer(funcPC(exit_trampoline)), unsafe.Pointer(&code))
+}
+func exit_trampoline()
+
+//go:nosplit
+//go:cgo_unsafe_args
+func getthrid() (tid int32) {
+	libcCall(unsafe.Pointer(funcPC(getthrid_trampoline)), unsafe.Pointer(&tid))
+	return
+}
+func getthrid_trampoline()
+
+//go:nosplit
+//go:cgo_unsafe_args
+func raiseproc(sig uint32) {
+	libcCall(unsafe.Pointer(funcPC(raiseproc_trampoline)), unsafe.Pointer(&sig))
+}
+func raiseproc_trampoline()
+
+//go:nosplit
+//go:cgo_unsafe_args
+func thrkill(tid int32, sig int) {
+	libcCall(unsafe.Pointer(funcPC(thrkill_trampoline)), unsafe.Pointer(&tid))
+}
+func thrkill_trampoline()
+
+// mmap is used to do low-level memory allocation via mmap. Don't allow stack
+// splits, since this function (used by sysAlloc) is called in a lot of low-level
+// parts of the runtime and callers often assume it won't acquire any locks.
+// go:nosplit
+func mmap(addr unsafe.Pointer, n uintptr, prot, flags, fd int32, off uint32) (unsafe.Pointer, int) {
+	args := struct {
+		addr            unsafe.Pointer
+		n               uintptr
+		prot, flags, fd int32
+		off             uint32
+		ret1            unsafe.Pointer
+		ret2            int
+	}{addr, n, prot, flags, fd, off, nil, 0}
+	libcCall(unsafe.Pointer(funcPC(mmap_trampoline)), unsafe.Pointer(&args))
+	return args.ret1, args.ret2
+}
+func mmap_trampoline()
+
+//go:nosplit
+//go:cgo_unsafe_args
+func munmap(addr unsafe.Pointer, n uintptr) {
+	libcCall(unsafe.Pointer(funcPC(munmap_trampoline)), unsafe.Pointer(&addr))
+}
+func munmap_trampoline()
+
+//go:nosplit
+//go:cgo_unsafe_args
+func madvise(addr unsafe.Pointer, n uintptr, flags int32) {
+	libcCall(unsafe.Pointer(funcPC(madvise_trampoline)), unsafe.Pointer(&addr))
+}
+func madvise_trampoline()
+
+//go:nosplit
+//go:cgo_unsafe_args
+func open(name *byte, mode, perm int32) (ret int32) {
+	return libcCall(unsafe.Pointer(funcPC(open_trampoline)), unsafe.Pointer(&name))
+}
+func open_trampoline()
+
+//go:nosplit
+//go:cgo_unsafe_args
+func closefd(fd int32) int32 {
+	return libcCall(unsafe.Pointer(funcPC(close_trampoline)), unsafe.Pointer(&fd))
+}
+func close_trampoline()
+
+//go:nosplit
+//go:cgo_unsafe_args
+func read(fd int32, p unsafe.Pointer, n int32) int32 {
+	return libcCall(unsafe.Pointer(funcPC(read_trampoline)), unsafe.Pointer(&fd))
+}
+func read_trampoline()
+
+//go:nosplit
+//go:cgo_unsafe_args
+func write1(fd uintptr, p unsafe.Pointer, n int32) int32 {
+	return libcCall(unsafe.Pointer(funcPC(write_trampoline)), unsafe.Pointer(&fd))
+}
+func write_trampoline()
+
+func pipe() (r, w int32, errno int32) {
+	return pipe2(0)
+}
+
+func pipe2(flags int32) (r, w int32, errno int32) {
+	var p [2]int32
+	args := struct {
+		p     unsafe.Pointer
+		flags int32
+	}{noescape(unsafe.Pointer(&p)), flags}
+	errno = libcCall(unsafe.Pointer(funcPC(pipe2_trampoline)), unsafe.Pointer(&args))
+	return p[0], p[1], errno
+}
+func pipe2_trampoline()
+
+//go:nosplit
+//go:cgo_unsafe_args
+func setitimer(mode int32, new, old *itimerval) {
+	libcCall(unsafe.Pointer(funcPC(setitimer_trampoline)), unsafe.Pointer(&mode))
+}
+func setitimer_trampoline()
+
+//go:nosplit
+//go:cgo_unsafe_args
+func usleep(usec uint32) {
+	libcCall(unsafe.Pointer(funcPC(usleep_trampoline)), unsafe.Pointer(&usec))
+}
+func usleep_trampoline()
+
+//go:nosplit
+//go:cgo_unsafe_args
+func sysctl(mib *uint32, miblen uint32, out *byte, size *uintptr, dst *byte, ndst uintptr) int32 {
+	return libcCall(unsafe.Pointer(funcPC(sysctl_trampoline)), unsafe.Pointer(&mib))
+}
+func sysctl_trampoline()
+
+//go:nosplit
+//go:cgo_unsafe_args
+func fcntl(fd, cmd, arg int32) int32 {
+	return libcCall(unsafe.Pointer(funcPC(fcntl_trampoline)), unsafe.Pointer(&fd))
+}
+func fcntl_trampoline()
+
+//go:nosplit
+func nanotime1() int64 {
+	var ts timespec
+	args := struct {
+		clock_id int32
+		tp       unsafe.Pointer
+	}{_CLOCK_MONOTONIC, unsafe.Pointer(&ts)}
+	libcCall(unsafe.Pointer(funcPC(clock_gettime_trampoline)), unsafe.Pointer(&args))
+	return ts.tv_sec*1e9 + int64(ts.tv_nsec)
+}
+func clock_gettime_trampoline()
+
+//go:nosplit
+func walltime1() (int64, int32) {
+	var ts timespec
+	args := struct {
+		clock_id int32
+		tp       unsafe.Pointer
+	}{_CLOCK_REALTIME, unsafe.Pointer(&ts)}
+	libcCall(unsafe.Pointer(funcPC(clock_gettime_trampoline)), unsafe.Pointer(&args))
+	return ts.tv_sec, int32(ts.tv_nsec)
+}
+
+//go:nosplit
+//go:cgo_unsafe_args
+func kqueue() int32 {
+	return libcCall(unsafe.Pointer(funcPC(kqueue_trampoline)), nil)
+}
+func kqueue_trampoline()
+
+//go:nosplit
+//go:cgo_unsafe_args
+func kevent(kq int32, ch *keventt, nch int32, ev *keventt, nev int32, ts *timespec) int32 {
+	return libcCall(unsafe.Pointer(funcPC(kevent_trampoline)), unsafe.Pointer(&kq))
+}
+func kevent_trampoline()
+
+//go:nosplit
+//go:cgo_unsafe_args
+func sigaction(sig uint32, new *sigactiont, old *sigactiont) {
+	libcCall(unsafe.Pointer(funcPC(sigaction_trampoline)), unsafe.Pointer(&sig))
+}
+func sigaction_trampoline()
+
+//go:nosplit
+//go:cgo_unsafe_args
+func sigprocmask(how uint32, new *sigset, old *sigset) {
+	libcCall(unsafe.Pointer(funcPC(sigprocmask_trampoline)), unsafe.Pointer(&how))
+}
+func sigprocmask_trampoline()
+
+//go:nosplit
+//go:cgo_unsafe_args
+func sigaltstack(new *stackt, old *stackt) {
+	libcCall(unsafe.Pointer(funcPC(sigaltstack_trampoline)), unsafe.Pointer(&new))
+}
+func sigaltstack_trampoline()
+
+// Not used on OpenBSD, but must be defined.
+func exitThread(wait *uint32) {
+}
+
+//go:nosplit
+func closeonexec(fd int32) {
+	fcntl(fd, _F_SETFD, _FD_CLOEXEC)
+}
+
+//go:nosplit
+func setNonblock(fd int32) {
+	flags := fcntl(fd, _F_GETFL, 0)
+	fcntl(fd, _F_SETFL, flags|_O_NONBLOCK)
+}
+
+// Tell the linker that the libc_* functions are to be found
+// in a system library, with the libc_ prefix missing.
+
+//go:cgo_import_dynamic libc_errno __errno "libc.so"
+//go:cgo_import_dynamic libc_exit exit "libc.so"
+//go:cgo_import_dynamic libc_getthrid getthrid "libc.so"
+//go:cgo_import_dynamic libc_sched_yield sched_yield "libc.so"
+//go:cgo_import_dynamic libc_thrkill thrkill "libc.so"
+
+//go:cgo_import_dynamic libc_mmap mmap "libc.so"
+//go:cgo_import_dynamic libc_munmap munmap "libc.so"
+//go:cgo_import_dynamic libc_madvise madvise "libc.so"
+
+//go:cgo_import_dynamic libc_open open "libc.so"
+//go:cgo_import_dynamic libc_close close "libc.so"
+//go:cgo_import_dynamic libc_read read "libc.so"
+//go:cgo_import_dynamic libc_write write "libc.so"
+//go:cgo_import_dynamic libc_pipe2 pipe2 "libc.so"
+
+//go:cgo_import_dynamic libc_clock_gettime clock_gettime "libc.so"
+//go:cgo_import_dynamic libc_setitimer setitimer "libc.so"
+//go:cgo_import_dynamic libc_usleep usleep "libc.so"
+//go:cgo_import_dynamic libc_sysctl sysctl "libc.so"
+//go:cgo_import_dynamic libc_fcntl fcntl "libc.so"
+//go:cgo_import_dynamic libc_getpid getpid "libc.so"
+//go:cgo_import_dynamic libc_kill kill "libc.so"
+//go:cgo_import_dynamic libc_kqueue kqueue "libc.so"
+//go:cgo_import_dynamic libc_kevent kevent "libc.so"
+
+//go:cgo_import_dynamic libc_sigaction sigaction "libc.so"
+//go:cgo_import_dynamic libc_sigaltstack sigaltstack "libc.so"
+
+//go:cgo_import_dynamic _ _ "libc.so"
diff --git a/src/runtime/sys_openbsd_amd64.s b/src/runtime/sys_openbsd_amd64.s
index 1086557aab..4680a7f7aa 100644
--- a/src/runtime/sys_openbsd_amd64.s
+++ b/src/runtime/sys_openbsd_amd64.s
@@ -150,13 +150,23 @@ TEXT runtime·pthread_create_trampoline(SB),NOSPLIT,$0
 	POPQ	BP
 	RET
 
+TEXT runtime·thrkill_trampoline(SB),NOSPLIT,$0
+	PUSHQ	BP
+	MOVQ	SP, BP
+	MOVL	8(DI), SI		// arg 2 - signal
+	MOVQ	$0, DX			// arg 3 - tcb
+	MOVL	0(DI), DI		// arg 1 - tid
+	CALL	libc_thrkill(SB)
+	POPQ	BP
+	RET
+
 TEXT runtime·thrsleep_trampoline(SB),NOSPLIT,$0
 	PUSHQ	BP
 	MOVQ	SP, BP
 	MOVL	8(DI), SI		// arg 2 - clock_id
 	MOVQ	16(DI), DX		// arg 3 - abstime
-	MOVQ	24(DI), CX		// arg 3 - lock
-	MOVQ	32(DI), R8		// arg 4 - abort
+	MOVQ	24(DI), CX		// arg 4 - lock
+	MOVQ	32(DI), R8		// arg 5 - abort
 	MOVQ	0(DI), DI		// arg 1 - id
 	CALL	libc_thrsleep(SB)
 	POPQ	BP
@@ -171,6 +181,35 @@ TEXT runtime·thrwakeup_trampoline(SB),NOSPLIT,$0
 	POPQ	BP
 	RET
 
+TEXT runtime·exit_trampoline(SB),NOSPLIT,$0
+	PUSHQ	BP
+	MOVQ	SP, BP
+	MOVL	0(DI), DI		// arg 1 exit status
+	CALL	libc_exit(SB)
+	MOVL	$0xf1, 0xf1  // crash
+	POPQ	BP
+	RET
+
+TEXT runtime·getthrid_trampoline(SB),NOSPLIT,$0
+	PUSHQ	BP
+	MOVQ	SP, BP
+	MOVQ	DI, BX			// BX is caller-save
+	CALL	libc_getthrid(SB)
+	MOVL	AX, 0(BX)		// return value
+	POPQ	BP
+	RET
+
+TEXT runtime·raiseproc_trampoline(SB),NOSPLIT,$0
+	PUSHQ	BP
+	MOVQ	SP, BP
+	MOVL	0(DI), BX	// signal
+	CALL	libc_getpid(SB)
+	MOVL	AX, DI		// arg 1 pid
+	MOVL	BX, SI		// arg 2 signal
+	CALL	libc_kill(SB)
+	POPQ	BP
+	RET
+
 TEXT runtime·sched_yield_trampoline(SB),NOSPLIT,$0
 	PUSHQ	BP
 	MOVQ	SP, BP
@@ -178,290 +217,231 @@ TEXT runtime·sched_yield_trampoline(SB),NOSPLIT,$0
 	POPQ	BP
 	RET
 
-// Exit the entire program (like C exit)
-TEXT runtime·exit(SB),NOSPLIT,$-8
-	MOVL	code+0(FP), DI		// arg 1 - exit status
-	MOVL	$1, AX			// sys_exit
-	SYSCALL
-	MOVL	$0xf1, 0xf1		// crash
-	RET
-
-// func exitThread(wait *uint32)
-TEXT runtime·exitThread(SB),NOSPLIT,$0-8
-	MOVQ	wait+0(FP), DI		// arg 1 - notdead
-	MOVL	$302, AX		// sys___threxit
-	SYSCALL
-	MOVL	$0xf1, 0xf1		// crash
-	JMP	0(PC)
-
-TEXT runtime·open(SB),NOSPLIT,$-8
-	MOVQ	name+0(FP), DI		// arg 1 pathname
-	MOVL	mode+8(FP), SI		// arg 2 flags
-	MOVL	perm+12(FP), DX		// arg 3 mode
-	MOVL	$5, AX
-	SYSCALL
-	JCC	2(PC)
-	MOVL	$-1, AX
-	MOVL	AX, ret+16(FP)
-	RET
-
-TEXT runtime·closefd(SB),NOSPLIT,$-8
-	MOVL	fd+0(FP), DI		// arg 1 fd
-	MOVL	$6, AX
-	SYSCALL
-	JCC	2(PC)
-	MOVL	$-1, AX
-	MOVL	AX, ret+8(FP)
-	RET
-
-TEXT runtime·read(SB),NOSPLIT,$-8
-	MOVL	fd+0(FP), DI		// arg 1 fd
-	MOVQ	p+8(FP), SI		// arg 2 buf
-	MOVL	n+16(FP), DX		// arg 3 count
-	MOVL	$3, AX
-	SYSCALL
-	JCC	2(PC)
-	NEGQ	AX			// caller expects negative errno
-	MOVL	AX, ret+24(FP)
-	RET
-
-// func pipe() (r, w int32, errno int32)
-TEXT runtime·pipe(SB),NOSPLIT,$0-12
-	LEAQ	r+0(FP), DI
-	MOVL	$263, AX
-	SYSCALL
-	MOVL	AX, errno+8(FP)
-	RET
-
-// func pipe2(flags int32) (r, w int32, errno int32)
-TEXT runtime·pipe2(SB),NOSPLIT,$0-20
-	LEAQ	r+8(FP), DI
-	MOVL	flags+0(FP), SI
-	MOVL	$101, AX
-	SYSCALL
-	MOVL	AX, errno+16(FP)
-	RET
-
-TEXT runtime·write1(SB),NOSPLIT,$-8
-	MOVQ	fd+0(FP), DI		// arg 1 - fd
-	MOVQ	p+8(FP), SI		// arg 2 - buf
-	MOVL	n+16(FP), DX		// arg 3 - nbyte
-	MOVL	$4, AX			// sys_write
-	SYSCALL
-	JCC	2(PC)
-	NEGQ	AX			// caller expects negative errno
-	MOVL	AX, ret+24(FP)
-	RET
-
-TEXT runtime·usleep(SB),NOSPLIT,$16
-	MOVL	$0, DX
-	MOVL	usec+0(FP), AX
-	MOVL	$1000000, CX
-	DIVL	CX
-	MOVQ	AX, 0(SP)		// tv_sec
-	MOVL	$1000, AX
-	MULL	DX
-	MOVQ	AX, 8(SP)		// tv_nsec
-
-	MOVQ	SP, DI			// arg 1 - rqtp
-	MOVQ	$0, SI			// arg 2 - rmtp
-	MOVL	$91, AX			// sys_nanosleep
-	SYSCALL
-	RET
-
-TEXT runtime·getthrid(SB),NOSPLIT,$0-4
-	MOVL	$299, AX		// sys_getthrid
-	SYSCALL
-	MOVL	AX, ret+0(FP)
-	RET
-
-TEXT runtime·thrkill(SB),NOSPLIT,$0-16
-	MOVL	tid+0(FP), DI		// arg 1 - tid
-	MOVQ	sig+8(FP), SI		// arg 2 - signum
-	MOVQ	$0, DX			// arg 3 - tcb
-	MOVL	$119, AX		// sys_thrkill
-	SYSCALL
-	RET
-
-TEXT runtime·raiseproc(SB),NOSPLIT,$16
-	MOVL	$20, AX			// sys_getpid
-	SYSCALL
-	MOVQ	AX, DI			// arg 1 - pid
-	MOVL	sig+0(FP), SI		// arg 2 - signum
-	MOVL	$122, AX		// sys_kill
-	SYSCALL
-	RET
-
-TEXT runtime·setitimer(SB),NOSPLIT,$-8
-	MOVL	mode+0(FP), DI		// arg 1 - which
-	MOVQ	new+8(FP), SI		// arg 2 - itv
-	MOVQ	old+16(FP), DX		// arg 3 - oitv
-	MOVL	$69, AX			// sys_setitimer
-	SYSCALL
-	RET
-
-// func walltime1() (sec int64, nsec int32)
-TEXT runtime·walltime1(SB), NOSPLIT, $32
-	MOVQ	$0, DI			// arg 1 - clock_id
-	LEAQ	8(SP), SI		// arg 2 - tp
-	MOVL	$87, AX			// sys_clock_gettime
-	SYSCALL
-	MOVQ	8(SP), AX		// sec
-	MOVQ	16(SP), DX		// nsec
-
-	// sec is in AX, nsec in DX
-	MOVQ	AX, sec+0(FP)
-	MOVL	DX, nsec+8(FP)
-	RET
-
-TEXT runtime·nanotime1(SB),NOSPLIT,$24
-	MOVQ	CLOCK_MONOTONIC, DI	// arg 1 - clock_id
-	LEAQ	8(SP), SI		// arg 2 - tp
-	MOVL	$87, AX			// sys_clock_gettime
-	SYSCALL
-	MOVQ	8(SP), AX		// sec
-	MOVQ	16(SP), DX		// nsec
-
-	// sec is in AX, nsec in DX
-	// return nsec in AX
-	IMULQ	$1000000000, AX
-	ADDQ	DX, AX
-	MOVQ	AX, ret+0(FP)
-	RET
-
-TEXT runtime·sigaction(SB),NOSPLIT,$-8
-	MOVL	sig+0(FP), DI		// arg 1 - signum
-	MOVQ	new+8(FP), SI		// arg 2 - nsa
-	MOVQ	old+16(FP), DX		// arg 3 - osa
-	MOVL	$46, AX
-	SYSCALL
-	JCC	2(PC)
-	MOVL	$0xf1, 0xf1		// crash
-	RET
-
-TEXT runtime·obsdsigprocmask(SB),NOSPLIT,$0
-	MOVL	how+0(FP), DI		// arg 1 - how
-	MOVL	new+4(FP), SI		// arg 2 - set
-	MOVL	$48, AX			// sys_sigprocmask
-	SYSCALL
-	JCC	2(PC)
-	MOVL	$0xf1, 0xf1		// crash
-	MOVL	AX, ret+8(FP)
-	RET
-
-TEXT runtime·mmap(SB),NOSPLIT,$0
-	MOVQ	addr+0(FP), DI		// arg 1 - addr
-	MOVQ	n+8(FP), SI		// arg 2 - len
-	MOVL	prot+16(FP), DX		// arg 3 - prot
-	MOVL	flags+20(FP), R10		// arg 4 - flags
-	MOVL	fd+24(FP), R8		// arg 5 - fd
-	MOVL	off+28(FP), R9
-	SUBQ	$16, SP
-	MOVQ	R9, 8(SP)		// arg 7 - offset (passed on stack)
-	MOVQ	$0, R9			// arg 6 - pad
-	MOVL	$197, AX
-	SYSCALL
-	JCC	ok
-	ADDQ	$16, SP
-	MOVQ	$0, p+32(FP)
-	MOVQ	AX, err+40(FP)
+TEXT runtime·mmap_trampoline(SB),NOSPLIT,$0
+	PUSHQ	BP			// make a frame; keep stack aligned
+	MOVQ	SP, BP
+	MOVQ	DI, BX
+	MOVQ	0(BX), DI		// arg 1 addr
+	MOVQ	8(BX), SI		// arg 2 len
+	MOVL	16(BX), DX		// arg 3 prot
+	MOVL	20(BX), CX		// arg 4 flags
+	MOVL	24(BX), R8		// arg 5 fid
+	MOVL	28(BX), R9		// arg 6 offset
+	CALL	libc_mmap(SB)
+	XORL	DX, DX
+	CMPQ	AX, $-1
+	JNE	ok
+	CALL	libc_errno(SB)
+	MOVLQSX	(AX), DX		// errno
+	XORQ	AX, AX
+ok:
+	MOVQ	AX, 32(BX)
+	MOVQ	DX, 40(BX)
+	POPQ	BP
 	RET
+
+TEXT runtime·munmap_trampoline(SB),NOSPLIT,$0
+	PUSHQ	BP
+	MOVQ	SP, BP
+	MOVQ	8(DI), SI		// arg 2 len
+	MOVQ	0(DI), DI		// arg 1 addr
+	CALL	libc_munmap(SB)
+	TESTQ	AX, AX
+	JEQ	2(PC)
+	MOVL	$0xf1, 0xf1  // crash
+	POPQ	BP
+	RET
+
+TEXT runtime·madvise_trampoline(SB), NOSPLIT, $0
+	PUSHQ	BP
+	MOVQ	SP, BP
+	MOVQ	8(DI), SI	// arg 2 len
+	MOVL	16(DI), DX	// arg 3 advice
+	MOVQ	0(DI), DI	// arg 1 addr
+	CALL	libc_madvise(SB)
+	// ignore failure - maybe pages are locked
+	POPQ	BP
+	RET
+
+TEXT runtime·open_trampoline(SB),NOSPLIT,$0
+	PUSHQ	BP
+	MOVQ	SP, BP
+	MOVL	8(DI), SI		// arg 2 - flags
+	MOVL	12(DI), DX		// arg 3 - mode
+	MOVQ	0(DI), DI		// arg 1 - path
+	XORL	AX, AX			// vararg: say "no float args"
+	CALL	libc_open(SB)
+	POPQ	BP
+	RET
+
+TEXT runtime·close_trampoline(SB),NOSPLIT,$0
+	PUSHQ	BP
+	MOVQ	SP, BP
+	MOVL	0(DI), DI		// arg 1 - fd
+	CALL	libc_close(SB)
+	POPQ	BP
+	RET
+
+TEXT runtime·read_trampoline(SB),NOSPLIT,$0
+	PUSHQ	BP
+	MOVQ	SP, BP
+	MOVQ	8(DI), SI		// arg 2 - buf
+	MOVL	16(DI), DX		// arg 3 - count
+	MOVL	0(DI), DI		// arg 1 - fd
+	CALL	libc_read(SB)
+	TESTL	AX, AX
+	JGE	noerr
+	CALL	libc_errno(SB)
+	MOVL	(AX), AX		// errno
+	NEGL	AX			// caller expects negative errno value
+noerr:
+	POPQ	BP
+	RET
+
+TEXT runtime·write_trampoline(SB),NOSPLIT,$0
+	PUSHQ	BP
+	MOVQ	SP, BP
+	MOVQ	8(DI), SI		// arg 2 buf
+	MOVL	16(DI), DX		// arg 3 count
+	MOVL	0(DI), DI		// arg 1 fd
+	CALL	libc_write(SB)
+	TESTL	AX, AX
+	JGE	noerr
+	CALL	libc_errno(SB)
+	MOVL	(AX), AX		// errno
+	NEGL	AX			// caller expects negative errno value
+noerr:
+	POPQ	BP
+	RET
+
+TEXT runtime·pipe2_trampoline(SB),NOSPLIT,$0
+	PUSHQ	BP
+	MOVQ	SP, BP
+	MOVL	8(DI), SI		// arg 2 flags
+	MOVQ	0(DI), DI		// arg 1 filedes
+	CALL	libc_pipe2(SB)
+	TESTL	AX, AX
+	JEQ	3(PC)
+	CALL	libc_errno(SB)
+	MOVL	(AX), AX		// errno
+	NEGL	AX			// caller expects negative errno value
+	POPQ	BP
+	RET
+
+TEXT runtime·setitimer_trampoline(SB),NOSPLIT,$0
+	PUSHQ	BP
+	MOVQ	SP, BP
+	MOVQ	8(DI), SI		// arg 2 new
+	MOVQ	16(DI), DX		// arg 3 old
+	MOVL	0(DI), DI		// arg 1 which
+	CALL	libc_setitimer(SB)
+	POPQ	BP
+	RET
+
+TEXT runtime·usleep_trampoline(SB),NOSPLIT,$0
+	PUSHQ	BP
+	MOVQ	SP, BP
+	MOVL	0(DI), DI		// arg 1 usec
+	CALL	libc_usleep(SB)
+	POPQ	BP
+	RET
+
+TEXT runtime·sysctl_trampoline(SB),NOSPLIT,$0
+	PUSHQ	BP
+	MOVQ	SP, BP
+	MOVL	8(DI), SI		// arg 2 miblen
+	MOVQ	16(DI), DX		// arg 3 out
+	MOVQ	24(DI), CX		// arg 4 size
+	MOVQ	32(DI), R8		// arg 5 dst
+	MOVQ	40(DI), R9		// arg 6 ndst
+	MOVQ	0(DI), DI		// arg 1 mib
+	CALL	libc_sysctl(SB)
+	POPQ	BP
+	RET
+
+TEXT runtime·kqueue_trampoline(SB),NOSPLIT,$0
+	PUSHQ	BP
+	MOVQ	SP, BP
+	CALL	libc_kqueue(SB)
+	POPQ	BP
+	RET
+
+TEXT runtime·kevent_trampoline(SB),NOSPLIT,$0
+	PUSHQ	BP
+	MOVQ	SP, BP
+	MOVQ	8(DI), SI		// arg 2 keventt
+	MOVL	16(DI), DX		// arg 3 nch
+	MOVQ	24(DI), CX		// arg 4 ev
+	MOVL	32(DI), R8		// arg 5 nev
+	MOVQ	40(DI), R9		// arg 6 ts
+	MOVL	0(DI), DI		// arg 1 kq
+	CALL	libc_kevent(SB)
+	CMPL	AX, $-1
+	JNE	ok
+	CALL	libc_errno(SB)
+	MOVL	(AX), AX		// errno
+	NEGL	AX			// caller expects negative errno value
 ok:
-	ADDQ	$16, SP
-	MOVQ	AX, p+32(FP)
-	MOVQ	$0, err+40(FP)
-	RET
-
-TEXT runtime·munmap(SB),NOSPLIT,$0
-	MOVQ	addr+0(FP), DI		// arg 1 - addr
-	MOVQ	n+8(FP), SI		// arg 2 - len
-	MOVL	$73, AX			// sys_munmap
-	SYSCALL
-	JCC	2(PC)
-	MOVL	$0xf1, 0xf1		// crash
-	RET
-
-TEXT runtime·madvise(SB),NOSPLIT,$0
-	MOVQ	addr+0(FP), DI		// arg 1 - addr
-	MOVQ	n+8(FP), SI		// arg 2 - len
-	MOVL	flags+16(FP), DX	// arg 3 - behav
-	MOVQ	$75, AX			// sys_madvise
-	SYSCALL
-	JCC	2(PC)
-	MOVL	$-1, AX
-	MOVL	AX, ret+24(FP)
-	RET
-
-TEXT runtime·sigaltstack(SB),NOSPLIT,$-8
-	MOVQ	new+0(FP), DI		// arg 1 - nss
-	MOVQ	old+8(FP), SI		// arg 2 - oss
-	MOVQ	$288, AX		// sys_sigaltstack
-	SYSCALL
-	JCC	2(PC)
-	MOVL	$0xf1, 0xf1		// crash
-	RET
-
-TEXT runtime·sysctl(SB),NOSPLIT,$0
-	MOVQ	mib+0(FP), DI		// arg 1 - name
-	MOVL	miblen+8(FP), SI		// arg 2 - namelen
-	MOVQ	out+16(FP), DX		// arg 3 - oldp
-	MOVQ	size+24(FP), R10		// arg 4 - oldlenp
-	MOVQ	dst+32(FP), R8		// arg 5 - newp
-	MOVQ	ndst+40(FP), R9		// arg 6 - newlen
-	MOVQ	$202, AX		// sys___sysctl
-	SYSCALL
-	JCC	4(PC)
-	NEGQ	AX
-	MOVL	AX, ret+48(FP)
-	RET
-	MOVL	$0, AX
-	MOVL	AX, ret+48(FP)
-	RET
-
-// int32 runtime·kqueue(void);
-TEXT runtime·kqueue(SB),NOSPLIT,$0
-	MOVL	$269, AX
-	SYSCALL
-	JCC	2(PC)
-	NEGQ	AX
-	MOVL	AX, ret+0(FP)
-	RET
-
-// int32 runtime·kevent(int kq, Kevent *changelist, int nchanges, Kevent *eventlist, int nevents, Timespec *timeout);
-TEXT runtime·kevent(SB),NOSPLIT,$0
-	MOVL	kq+0(FP), DI
-	MOVQ	ch+8(FP), SI
-	MOVL	nch+16(FP), DX
-	MOVQ	ev+24(FP), R10
-	MOVL	nev+32(FP), R8
-	MOVQ	ts+40(FP), R9
-	MOVL	$72, AX
-	SYSCALL
-	JCC	2(PC)
-	NEGQ	AX
-	MOVL	AX, ret+48(FP)
-	RET
-
-// void runtime·closeonexec(int32 fd);
-TEXT runtime·closeonexec(SB),NOSPLIT,$0
-	MOVL	fd+0(FP), DI	// fd
-	MOVQ	$2, SI		// F_SETFD
-	MOVQ	$1, DX		// FD_CLOEXEC
-	MOVL	$92, AX		// fcntl
-	SYSCALL
-	RET
-
-// func runtime·setNonblock(int32 fd)
-TEXT runtime·setNonblock(SB),NOSPLIT,$0-4
-	MOVL    fd+0(FP), DI  // fd
-	MOVQ    $3, SI  // F_GETFL
-	MOVQ    $0, DX
-	MOVL	$92, AX // fcntl
-	SYSCALL
-	MOVL	fd+0(FP), DI // fd
-	MOVQ	$4, SI // F_SETFL
-	MOVQ	$4, DX // O_NONBLOCK
-	ORL	AX, DX
-	MOVL	$92, AX // fcntl
-	SYSCALL
+	POPQ	BP
+	RET
+
+TEXT runtime·clock_gettime_trampoline(SB),NOSPLIT,$0
+	PUSHQ	BP			// make a frame; keep stack aligned
+	MOVQ	SP, BP
+	MOVQ	8(DI), SI		// arg 2 tp
+	MOVL	0(DI), DI		// arg 1 clock_id
+	CALL	libc_clock_gettime(SB)
+	TESTL	AX, AX
+	JEQ	2(PC)
+	MOVL	$0xf1, 0xf1  // crash
+	POPQ	BP
+	RET
+
+TEXT runtime·fcntl_trampoline(SB),NOSPLIT,$0
+	PUSHQ	BP
+	MOVQ	SP, BP
+	MOVL	4(DI), SI		// arg 2 cmd
+	MOVL	8(DI), DX		// arg 3 arg
+	MOVL	0(DI), DI		// arg 1 fd
+	XORL	AX, AX			// vararg: say "no float args"
+	CALL	libc_fcntl(SB)
+	POPQ	BP
+	RET
+
+TEXT runtime·sigaction_trampoline(SB),NOSPLIT,$0
+	PUSHQ	BP
+	MOVQ	SP, BP
+	MOVQ	8(DI), SI		// arg 2 new
+	MOVQ	16(DI), DX		// arg 3 old
+	MOVL	0(DI), DI		// arg 1 sig
+	CALL	libc_sigaction(SB)
+	TESTL	AX, AX
+	JEQ	2(PC)
+	MOVL	$0xf1, 0xf1  // crash
+	POPQ	BP
+	RET
+
+TEXT runtime·sigprocmask_trampoline(SB),NOSPLIT,$0
+	PUSHQ	BP
+	MOVQ	SP, BP
+	MOVQ	8(DI), SI	// arg 2 new
+	MOVQ	16(DI), DX	// arg 3 old
+	MOVL	0(DI), DI	// arg 1 how
+	CALL	libc_pthread_sigmask(SB)
+	TESTL	AX, AX
+	JEQ	2(PC)
+	MOVL	$0xf1, 0xf1  // crash
+	POPQ	BP
+	RET
+
+TEXT runtime·sigaltstack_trampoline(SB),NOSPLIT,$0
+	PUSHQ	BP
+	MOVQ	SP, BP
+	MOVQ	8(DI), SI		// arg 2 old
+	MOVQ	0(DI), DI		// arg 1 new
+	CALL	libc_sigaltstack(SB)
+	TESTQ	AX, AX
+	JEQ	2(PC)
+	MOVL	$0xf1, 0xf1  // crash
+	POPQ	BP
 	RET
diff --git a/src/runtime/timestub2.go b/src/runtime/timestub2.go
index 6d73aabc35..68777ee4a9 100644
--- a/src/runtime/timestub2.go
+++ b/src/runtime/timestub2.go
@@ -2,11 +2,12 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build !aix
 // +build !darwin
-// +build !windows
 // +build !freebsd
-// +build !aix
+// +build !openbsd
 // +build !solaris
+// +build !windows
 
 package runtime