cpu: don't depend on the golang.org/x/sys/unix package for AIX

gccgo support can happen in a future CL.

Updates golang/go#32102

Change-Id: Ic9e8d7b3e413079d277bdba565551845a2b78121
Reviewed-on: https://go-review.googlesource.com/c/sys/+/179178
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

cpu/asm_aix_ppc64.s

@@ -0,0 +1,17 @@
+// 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 !gccgo
+
+#include "textflag.h"
+
+//
+// System calls for ppc64, AIX are implemented in runtime/syscall_aix.go
+//
+
+TEXT ·syscall6(SB),NOSPLIT,$0-88
+	JMP	syscall·syscall6(SB)
+
+TEXT ·rawSyscall6(SB),NOSPLIT,$0-88
+	JMP	syscall·rawSyscall6(SB)

cpu/cpu_aix_ppc64.go

@@ -6,8 +6,6 @@
 
 package cpu
 
-import "golang.org/x/sys/unix"
-
 const cacheLineSize = 128
 
 const (
@@ -18,7 +16,7 @@ const (
 )
 
 func init() {
-	impl := unix.Getsystemcfg(_SC_IMPL)
+	impl := getsystemcfg(_SC_IMPL)
 	if impl&_IMPL_POWER8 != 0 {
 		PPC64.IsPOWER8 = true
 	}
@@ -28,3 +26,9 @@ func init() {
 
 	Initialized = true
 }
+
+func getsystemcfg(label int) (n uint64) {
+	r0, _ := callgetsystemcfg(label)
+	n = uint64(r0)
+	return
+}

cpu/syscall_aix_ppc64_gc.go

@@ -0,0 +1,34 @@
+// 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.
+
+// Minimal copy of x/sys/unix so the cpu package can make a
+// system call on AIX without depending on x/sys/unix.
+// (See golang.org/issue/32102)
+
+// +build aix,ppc64
+// +build !gccgo
+
+package cpu
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+//go:cgo_import_dynamic libc_getsystemcfg getsystemcfg "libc.a/shr_64.o"
+
+type syscallFunc uintptr
+
+var libc_getsystemcfg syscallFunc
+
+type errno = syscall.Errno
+
+// Implemented in runtime/syscall_aix.go.
+func rawSyscall6(trap, nargs, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err errno)
+func syscall6(trap, nargs, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err errno)
+
+func callgetsystemcfg(label int) (r1 uintptr, e1 errno) {
+	r1, _, e1 = syscall6(uintptr(unsafe.Pointer(&libc_getsystemcfg)), 1, uintptr(label), 0, 0, 0, 0, 0)
+	return
+}