// Copyright 2023 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.

// Tests syscall P stealing.
//
// Specifically, it tests a scenerio wherein, without a
// P sequence number of GoSyscallBegin, the syscall that
// a ProcSteal applies to is ambiguous. This only happens in
// practice when the events aren't already properly ordered

// license that can be found in the LICENSE file.

// Package syscall provides the syscall primitives required for the runtime.
package syscall

import (
	"unsafe"
)

// TODO(https://go.dev/issue/51087): This package is incomplete and currently
// only contains very minimal support for Linux.

// Syscall6 calls system call number 'num' with arguments a1-6.
func Syscall6(num, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, errno uintptr)

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Tests a G being created from within a syscall.
//
// Specifically, it tests a scenerio wherein a C
// thread is calling into Go, creating a goroutine in
// a syscall (in the tracer's model). Because the actual
// m can be reused, it's possible for that m to have never
// had its P (in _Psyscall) stolen if the runtime doesn't

// license that can be found in the LICENSE file.

// Tests syscall P stealing at a generation boundary.

package main

import (
	"internal/trace"
	"internal/trace/event/go122"
	testgen "internal/trace/internal/testgen/go122"
)

func main() {
	testgen.Main(gen)
}

func gen(t *testgen.Trace) {
	g := t.Generation(1)

	// One goroutine is exiting with a syscall. It already
	// acquired a new P.

// license that can be found in the LICENSE file.

// Tests syscall P stealing.

package main

import (
	"internal/trace"
	"internal/trace/event/go122"
	testgen "internal/trace/internal/testgen/go122"
)

func main() {
	testgen.Main(gen)
}

func gen(t *testgen.Trace) {
	g := t.Generation(1)

	// One goroutine enters a syscall, grabs a P, and starts running.
	b0 := g.Batch(trace.ThreadID(0), 0)

//go:build linux && (mips || mipsle)

#include "textflag.h"

// func Syscall6(num, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, errno uintptr)
//
// The 5th and 6th arg go at sp+16, sp+20.
// Note that frame size of 20 means that 24 bytes gets reserved on stack.
TEXT ·Syscall6(SB),NOSPLIT,$20-40
	MOVW	num+0(FP), R2	// syscall entry
	MOVW	a1+4(FP), R4
	MOVW	a2+8(FP), R5
	MOVW	a3+12(FP), R6
	MOVW	a4+16(FP), R7

#include "textflag.h"

// func Syscall6(num, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, errno uintptr)
TEXT ·Syscall6(SB),NOSPLIT,$0-80
	MOVV	num+0(FP), R2	// syscall entry
	MOVV	a1+8(FP), R4
	MOVV	a2+16(FP), R5
	MOVV	a3+24(FP), R6
	MOVV	a4+32(FP), R7
	MOVV	a5+40(FP), R8
	MOVV	a6+48(FP), R9
	MOVV	R0, R3	// reset R3 to 0 as 1-ret SYSCALL keeps it
	SYSCALL
	BEQ	R7, ok
	MOVV	$-1, R1
	MOVV	R1, r1+56(FP)

// license that can be found in the LICENSE file.

// Tests syscall P stealing.

package main

import (
	"internal/trace"
	"internal/trace/event/go122"
	testgen "internal/trace/internal/testgen/go122"
)

func main() {
	testgen.Main(gen)
}

func gen(t *testgen.Trace) {
	g := t.Generation(1)

	// One goroutine enters a syscall.
	b0 := g.Batch(trace.ThreadID(0), 0)

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Tests a G being created from within a syscall.
//
// Specifically, it tests a scenerio wherein a C
// thread is calling into Go, creating a goroutine in
// a syscall (in the tracer's model). The system is free
// to reuse thread IDs, so first a thread ID is used to
// call into Go, and then is used for a Go-created thread.
//

// license that can be found in the LICENSE file.

#include "textflag.h"

// func Syscall6(num, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, errno uintptr)
TEXT ·Syscall6(SB),NOSPLIT,$0-80
	MOVD	num+0(FP), R1	// syscall entry
	MOVD	a1+8(FP), R2
	MOVD	a2+16(FP), R3
	MOVD	a3+24(FP), R4
	MOVD	a4+32(FP), R5
	MOVD	a5+40(FP), R6
	MOVD	a6+48(FP), R7
	SYSCALL
	MOVD	$0xfffffffffffff001, R8
	CMPUBLT	R2, R8, ok
	MOVD	$-1, r1+56(FP)