src/syscall/zx/mkfuchsia.go - third_party/go - Git at Google

 // Copyright 2016 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

 // Parses syscalls.abigen of Fuchsia's zircon kernel and produces Go assembly
 // for calling the system calls.
 //
 // Regenerate syscall/zx with:
 //
 //	go run mkfuchsia.go -stubs > syscalls_fuchsia.go
 //	go run mkfuchsia.go -goarch=amd64 > syscalls_fuchsia_amd64.s
 //	go run mkfuchsia.go -goarch=arm64 > syscalls_fuchsia_arm64.s
 //	gofmt -w syscalls_fuchsia.go
 package main

 import (
 	"bytes"
 	"flag"
 	"fmt"
 	"io/ioutil"
 	"log"
 	"os"
 	"path/filepath"

 	"internal/fuchsia/abigen"
 )

 var (
 	stubs       = flag.Bool("stubs", false, "print only Go function stubs")
 	goarch      = flag.String("goarch", "amd64", "arch to print asm for")
 	fuchsiaRoot = flag.String("fuchsia_root", filepath.Join(os.Getenv("HOME"), "fuchsia"), "path to fuchsia root")
 )

 func main() {
 	flag.Parse()
 	sdkArch := ""
 	switch *goarch {
 	case "amd64":
 		sdkArch = "x86_64"
 	case "arm64":
 		sdkArch = "aarch64"
 	default:
 		log.Fatalf("GOARCH=%s not supported", *goarch)
 	}
 	_ = sdkArch

 	syscallsFile := filepath.Join(*fuchsiaRoot, "/zircon/system/public/zircon/syscalls.abigen")
 	if args := flag.Args(); len(args) != 0 {
 		syscallsFile = args[0]
 	}

 	b, err := ioutil.ReadFile(syscallsFile)
 	if err != nil {
 		log.Fatal(err)
 	}

 	p := abigen.NewParser(b, syscallsFile)
 	defs, err := p.Parse()
 	if err != nil {
 		log.Fatal(err)
 	}

 	buf := new(bytes.Buffer)
 	if *stubs {
 		fmt.Fprint(buf, stubsHeader[1:])
 		for _, def := range defs {
 			fmt.Fprintf(buf, "//go:cgo_import_dynamic vdso_zx_%s zx_%s\n", def.Name, def.Name)
 		}
 		fmt.Fprint(buf, "\n")
 		for _, def := range defs {
 			fmt.Fprintf(buf, "//go:linkname vdso_zx_%s vdso_zx_%s\n", def.Name, def.Name)
 		}
 		fmt.Fprint(buf, "\nvar (\n")
 		for _, def := range defs {
 			fmt.Fprintf(buf, "\tvdso_zx_%s uintptr\n", def.Name)
 		}
 		fmt.Fprint(buf, ")\n\n")
 		for _, def := range defs {
 			fmt.Fprint(buf, "//go:noescape\n")
 			fmt.Fprint(buf, "//go:nosplit\n")
 			printStub(buf, def)
 			fmt.Fprint(buf, "\n")
 		}
 	} else {
 		fmt.Fprint(buf, asmHeader[1:])
 		for _, def := range defs {
 			fmt.Fprint(buf, "// ")
 			printStub(buf, def)
 			printAsm(buf, def)
 			fmt.Fprint(buf, "\n")
 		}
 	}
 	buf.WriteTo(os.Stdout)
 }

 const stubsHeader = `
 // 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.

 // Zircon system calls for the Fuchsia OS.
 // Generated by mkfuchsia.go, do not edit.

 package zx

 import "unsafe"

 `

 const asmHeader = `
 // Copyright 2016 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.

 // Zircon system calls for the Fuchsia OS.
 // Generated by mkfuchsia.go, do not edit.

 #include "textflag.h"

 `

 func printStub(buf *bytes.Buffer, def abigen.SysDef) {
 	fmt.Fprintf(buf, "func %s(", def.GoName())
 	for i, arg := range def.Args {
 		if arg.Type == (abigen.SysType{}) {
 			continue
 		}
 		if i > 0 {
 			fmt.Fprint(buf, ", ")
 		}
 		fmt.Fprintf(buf, "%s ", arg.Name)
 		fmt.Fprintf(buf, "%s", arg.Type.GoType())
 	}
 	fmt.Fprint(buf, ")")
 	if def.Ret != (abigen.SysType{}) {
 		fmt.Fprint(buf, " ")
 		fmt.Fprintf(buf, "%s", def.Ret.GoType())
 	}
 	fmt.Fprint(buf, "\n")
 }

 // amd64RegArgs is the amd64 registers in function argument calling convention order
 var amd64RegArgs = []string{"DI", "SI", "DX", "CX", "R8", "R9", "R12", "R13"}

 // arm64RegArgs is the arm64 registers in function argument calling convention order
 var arm64RegArgs = []string{"R0", "R1", "R2", "R3", "R4", "R5", "R6", "R7"}

 // blockingSyscalls is a map of known syscalls which may block.
 var blockingSyscalls = map[string]bool{
 	"port_wait":        true,
 	"object_wait_one":  true,
 	"object_wait_many": true,
 }

 func printAsm(buf *bytes.Buffer, def abigen.SysDef) {
 	// The summed size of all arguments
 	argSize := 0
 	for _, arg := range def.Args {
 		sz := arg.Type.Size()
 		if *goarch == "arm64" && sz == 1 {
 			sz = 8
 		}
 		for argSize%sz != 0 {
 			// Add padding until the 'argSize' is aligned to the type we are adding
 			argSize++
 		}
 		argSize += sz
 	}
 	if argSize%8 == 4 {
 		// Force the return argument on the stack to be 8-byte aligned, not 4-byte aligned
 		argSize += 4
 	}
 	retSize := def.Ret.Size()

 	var frameSize int
 	var regArgs []string
 	var callIns, retReg, suffix4, suffix8 string
 	switch *goarch {
 	case "amd64":
 		regArgs = amd64RegArgs
 		callIns = "CALL"
 		retReg = "AX"
 		suffix8 = "Q"
 		suffix4 = "L"
 		switch len(def.Args) {
 		case 7:
 			frameSize = 16 + 8
 		case 8:
 			frameSize = 16 + 2*8
 		}
 	case "arm64":
 		regArgs = arm64RegArgs
 		callIns = "BL"
 		retReg = "R0"
 		suffix8 = "D"
 		suffix4 = "W"
 	default:
 		panic(fmt.Sprintf("goarch=%s not supported", *goarch))
 	}

 	fmt.Fprintf(buf, "TEXT ·%s(SB),NOSPLIT,$%d-%d\n", def.GoName(), frameSize, argSize+retSize)

 	if _, ok := blockingSyscalls[def.Name]; ok {
 		fmt.Fprintf(buf, "\tCALL runtime·entersyscall(SB)\n")
 	}
 	off := 0
 	for i, arg := range def.Args {
 		name := arg.Name
 		suffix := suffix8
 		t := arg.Type
 		sz := t.Size()
 		if sz == 4 {
 			suffix = suffix4
 		} else if *goarch == "arm64" && sz == 1 {
 			sz = 8
 		}
 		for off%sz != 0 {
 			// Add padding until the offset is aligned to the type we are accessing
 			off++
 		}

 		fmt.Fprintf(buf, "\tMOV%s %s+%d(FP), %s\n", suffix, name, off, regArgs[i])
 		off += sz
 	}
 	switch *goarch {
 	case "amd64":
 		if len(def.Args) >= 7 {
 			fmt.Fprintf(buf, "\tMOVQ SP, BP   // BP is preserved across vsdo call by the x86-64 ABI\n")
 			fmt.Fprintf(buf, "\tANDQ $~15, SP // stack alignment for x86-64 ABI\n")
 			if len(def.Args) == 8 {
 				fmt.Fprintf(buf, "\tPUSHQ R13\n")
 			}
 			fmt.Fprintf(buf, "\tPUSHQ R12\n")
 		}
 		fmt.Fprintf(buf, "\tMOVQ vdso_zx_%s(SB), AX\n", def.Name)
 		fmt.Fprintf(buf, "\tCALL AX\n")
 		if len(def.Args) >= 7 {
 			fmt.Fprintf(buf, "\tPOPQ R12\n")
 			if len(def.Args) == 8 {
 				fmt.Fprintf(buf, "\tPOPQ R13\n")
 			}
 			fmt.Fprintf(buf, "\tMOVQ BP, SP\n")
 		}
 	case "arm64":
 		fmt.Fprintf(buf, "\tBL vdso_zx_%s(SB)\n", def.Name)
 	}
 	if retSize := def.Ret.Size(); retSize > 0 {
 		suffix := suffix8
 		if retSize == 4 {
 			suffix = suffix4
 		}
 		fmt.Fprintf(buf, "\tMOV%s %s, ret+%d(FP)\n", suffix, retReg, argSize)
 	}
 	if _, ok := blockingSyscalls[def.Name]; ok {
 		fmt.Fprintf(buf, "\t%s runtime·exitsyscall(SB)\n", callIns)
 	}
 	fmt.Fprintf(buf, "\tRET\n")
 }
	// Copyright 2016 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

	// Parses syscalls.abigen of Fuchsia's zircon kernel and produces Go assembly
	// for calling the system calls.
	//
	// Regenerate syscall/zx with:
	//
	// go run mkfuchsia.go -stubs > syscalls_fuchsia.go
	// go run mkfuchsia.go -goarch=amd64 > syscalls_fuchsia_amd64.s
	// go run mkfuchsia.go -goarch=arm64 > syscalls_fuchsia_arm64.s
	// gofmt -w syscalls_fuchsia.go
	package main

	import (
	"bytes"
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"path/filepath"

	"internal/fuchsia/abigen"
	)

	var (
	stubs = flag.Bool("stubs", false, "print only Go function stubs")
	goarch = flag.String("goarch", "amd64", "arch to print asm for")
	fuchsiaRoot = flag.String("fuchsia_root", filepath.Join(os.Getenv("HOME"), "fuchsia"), "path to fuchsia root")
	)

	func main() {
	flag.Parse()
	sdkArch := ""
	switch *goarch {
	case "amd64":
	sdkArch = "x86_64"
	case "arm64":
	sdkArch = "aarch64"
	default:
	log.Fatalf("GOARCH=%s not supported", *goarch)
	}
	_ = sdkArch

	syscallsFile := filepath.Join(*fuchsiaRoot, "/zircon/system/public/zircon/syscalls.abigen")
	if args := flag.Args(); len(args) != 0 {
	syscallsFile = args[0]
	}

	b, err := ioutil.ReadFile(syscallsFile)
	if err != nil {
	log.Fatal(err)
	}

	p := abigen.NewParser(b, syscallsFile)
	defs, err := p.Parse()
	if err != nil {
	log.Fatal(err)
	}

	buf := new(bytes.Buffer)
	if *stubs {
	fmt.Fprint(buf, stubsHeader[1:])
	for _, def := range defs {
	fmt.Fprintf(buf, "//go:cgo_import_dynamic vdso_zx_%s zx_%s\n", def.Name, def.Name)
	}
	fmt.Fprint(buf, "\n")
	for _, def := range defs {
	fmt.Fprintf(buf, "//go:linkname vdso_zx_%s vdso_zx_%s\n", def.Name, def.Name)
	}
	fmt.Fprint(buf, "\nvar (\n")
	for _, def := range defs {
	fmt.Fprintf(buf, "\tvdso_zx_%s uintptr\n", def.Name)
	}
	fmt.Fprint(buf, ")\n\n")
	for _, def := range defs {
	fmt.Fprint(buf, "//go:noescape\n")
	fmt.Fprint(buf, "//go:nosplit\n")
	printStub(buf, def)
	fmt.Fprint(buf, "\n")
	}
	} else {
	fmt.Fprint(buf, asmHeader[1:])
	for _, def := range defs {
	fmt.Fprint(buf, "// ")
	printStub(buf, def)
	printAsm(buf, def)
	fmt.Fprint(buf, "\n")
	}
	}
	buf.WriteTo(os.Stdout)
	}

	const stubsHeader = `
	// 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.

	// Zircon system calls for the Fuchsia OS.
	// Generated by mkfuchsia.go, do not edit.

	package zx

	import "unsafe"

	`

	const asmHeader = `
	// Copyright 2016 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.

	// Zircon system calls for the Fuchsia OS.
	// Generated by mkfuchsia.go, do not edit.

	#include "textflag.h"

	`

	func printStub(buf *bytes.Buffer, def abigen.SysDef) {
	fmt.Fprintf(buf, "func %s(", def.GoName())
	for i, arg := range def.Args {
	if arg.Type == (abigen.SysType{}) {
	continue
	}
	if i > 0 {
	fmt.Fprint(buf, ", ")
	}
	fmt.Fprintf(buf, "%s ", arg.Name)
	fmt.Fprintf(buf, "%s", arg.Type.GoType())
	}
	fmt.Fprint(buf, ")")
	if def.Ret != (abigen.SysType{}) {
	fmt.Fprint(buf, " ")
	fmt.Fprintf(buf, "%s", def.Ret.GoType())
	}
	fmt.Fprint(buf, "\n")
	}

	// amd64RegArgs is the amd64 registers in function argument calling convention order
	var amd64RegArgs = []string{"DI", "SI", "DX", "CX", "R8", "R9", "R12", "R13"}

	// arm64RegArgs is the arm64 registers in function argument calling convention order
	var arm64RegArgs = []string{"R0", "R1", "R2", "R3", "R4", "R5", "R6", "R7"}

	// blockingSyscalls is a map of known syscalls which may block.
	var blockingSyscalls = map[string]bool{
	"port_wait": true,
	"object_wait_one": true,
	"object_wait_many": true,
	}

	func printAsm(buf *bytes.Buffer, def abigen.SysDef) {
	// The summed size of all arguments
	argSize := 0
	for _, arg := range def.Args {
	sz := arg.Type.Size()
	if *goarch == "arm64" && sz == 1 {
	sz = 8
	}
	for argSize%sz != 0 {
	// Add padding until the 'argSize' is aligned to the type we are adding
	argSize++
	}
	argSize += sz
	}
	if argSize%8 == 4 {
	// Force the return argument on the stack to be 8-byte aligned, not 4-byte aligned
	argSize += 4
	}
	retSize := def.Ret.Size()

	var frameSize int
	var regArgs []string
	var callIns, retReg, suffix4, suffix8 string
	switch *goarch {
	case "amd64":
	regArgs = amd64RegArgs
	callIns = "CALL"
	retReg = "AX"
	suffix8 = "Q"
	suffix4 = "L"
	switch len(def.Args) {
	case 7:
	frameSize = 16 + 8
	case 8:
	frameSize = 16 + 2*8
	}
	case "arm64":
	regArgs = arm64RegArgs
	callIns = "BL"
	retReg = "R0"
	suffix8 = "D"
	suffix4 = "W"
	default:
	panic(fmt.Sprintf("goarch=%s not supported", *goarch))
	}

	fmt.Fprintf(buf, "TEXT ·%s(SB),NOSPLIT,$%d-%d\n", def.GoName(), frameSize, argSize+retSize)

	if _, ok := blockingSyscalls[def.Name]; ok {
	fmt.Fprintf(buf, "\tCALL runtime·entersyscall(SB)\n")
	}
	off := 0
	for i, arg := range def.Args {
	name := arg.Name
	suffix := suffix8
	t := arg.Type
	sz := t.Size()
	if sz == 4 {
	suffix = suffix4
	} else if *goarch == "arm64" && sz == 1 {
	sz = 8
	}
	for off%sz != 0 {
	// Add padding until the offset is aligned to the type we are accessing
	off++
	}

	fmt.Fprintf(buf, "\tMOV%s %s+%d(FP), %s\n", suffix, name, off, regArgs[i])
	off += sz
	}
	switch *goarch {
	case "amd64":
	if len(def.Args) >= 7 {
	fmt.Fprintf(buf, "\tMOVQ SP, BP // BP is preserved across vsdo call by the x86-64 ABI\n")
	fmt.Fprintf(buf, "\tANDQ $~15, SP // stack alignment for x86-64 ABI\n")
	if len(def.Args) == 8 {
	fmt.Fprintf(buf, "\tPUSHQ R13\n")
	}
	fmt.Fprintf(buf, "\tPUSHQ R12\n")
	}
	fmt.Fprintf(buf, "\tMOVQ vdso_zx_%s(SB), AX\n", def.Name)
	fmt.Fprintf(buf, "\tCALL AX\n")
	if len(def.Args) >= 7 {
	fmt.Fprintf(buf, "\tPOPQ R12\n")
	if len(def.Args) == 8 {
	fmt.Fprintf(buf, "\tPOPQ R13\n")
	}
	fmt.Fprintf(buf, "\tMOVQ BP, SP\n")
	}
	case "arm64":
	fmt.Fprintf(buf, "\tBL vdso_zx_%s(SB)\n", def.Name)
	}
	if retSize := def.Ret.Size(); retSize > 0 {
	suffix := suffix8
	if retSize == 4 {
	suffix = suffix4
	}
	fmt.Fprintf(buf, "\tMOV%s %s, ret+%d(FP)\n", suffix, retReg, argSize)
	}
	if _, ok := blockingSyscalls[def.Name]; ok {
	fmt.Fprintf(buf, "\t%s runtime·exitsyscall(SB)\n", callIns)
	}
	fmt.Fprintf(buf, "\tRET\n")
	}