internal/cpu,runtime: call cpu.initialize before alginit

runtime.alginit needs runtime/support_{aes,ssse3,sse41} feature flag
to init aeshash function but internal/cpu.init not be called yet.
This CL will call internal/cpu.initialize before runtime.alginit, so
that we can move all cpu features related code to internal/cpu.

Change-Id: I00b8e403ace3553f8c707563d95f27dade0bc853
Reviewed-on: https://go-review.googlesource.com/104636
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/cmd/compile/internal/gc/racewalk.go

@@ -27,7 +27,7 @@ import (
 
 // Do not instrument the following packages at all,
 // at best instrumentation would cause infinite recursion.
-var omit_pkgs = []string{"runtime/internal/atomic", "runtime/internal/sys", "runtime", "runtime/race", "runtime/msan"}
+var omit_pkgs = []string{"runtime/internal/atomic", "runtime/internal/sys", "runtime", "runtime/race", "runtime/msan", "internal/cpu"}
 
 // Only insert racefuncenterfp/racefuncexit into the following packages.
 // Memory accesses in the packages are either uninteresting or will cause false positives.

src/internal/cpu/cpu.go

@@ -98,3 +98,10 @@ type s390x struct {
 	HasVX bool // vector facility. Note: the runtime sets this when it processes auxv records.
 	_     [CacheLineSize]byte
 }
+
+// initialize examines the processor and sets the relevant variables above.
+// This is called by the runtime package early in program initialization,
+// before normal init functions are run.
+func initialize() {
+	doinit()
+}

src/internal/cpu/cpu_arm64.go

@@ -42,7 +42,7 @@ const (
 	hwcap_ASIMDFHM = (1 << 23)
 )
 
-func init() {
+func doinit() {
 	// HWCAP feature bits
 	ARM64.HasFP = isSet(arm64_hwcap, hwcap_FP)
 	ARM64.HasASIMD = isSet(arm64_hwcap, hwcap_ASIMD)

src/internal/cpu/cpu_no_init.go

@@ -0,0 +1,13 @@
+// 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 !386
+// +build !amd64
+// +build !amd64p32
+// +build !arm64
+
+package cpu
+
+func doinit() {
+}

src/internal/cpu/cpu_x86.go

@@ -14,7 +14,7 @@ func cpuid(eaxArg, ecxArg uint32) (eax, ebx, ecx, edx uint32)
 // xgetbv with ecx = 0 is implemented in cpu_x86.s.
 func xgetbv() (eax, edx uint32)
 
-func init() {
+func doinit() {
 	maxID, _, _, _ := cpuid(0, 0)
 
 	if maxID < 1 {

src/runtime/proc.go

@@ -466,6 +466,9 @@ const (
 	_GoidCacheBatch = 16
 )
 
+//go:linkname internal_cpu_initialize internal/cpu.initialize
+func internal_cpu_initialize()
+
 // The bootstrap sequence is:
 //
 //	call osinit
@@ -489,10 +492,11 @@ func schedinit() {
 	stackinit()
 	mallocinit()
 	mcommoninit(_g_.m)
-	alginit()       // maps must not be used before this call
+	internal_cpu_initialize() // must run before alginit
-	modulesinit()   // provides activeModules
+	alginit()                 // maps must not be used before this call
-	typelinksinit() // uses maps, activeModules
+	modulesinit()             // provides activeModules
-	itabsinit()     // uses activeModules
+	typelinksinit()           // uses maps, activeModules
+	itabsinit()               // uses activeModules
 
 	msigsave(_g_.m)
 	initSigmask = _g_.m.sigmask