use syscall.syscallX so that calls switch to the g0 stack

Author: TotallyGamerJet

dl.go

@@ -3,6 +3,7 @@ package dl
 import (
 	"errors"
 	"runtime"
+	"unsafe"
 )
 
 var (
@@ -133,8 +134,7 @@ func Open(path string, mode int) (*Dylib, error) {
 
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
-
-	handle := dlopen(p, mode)
+	handle, _, _ := syscall_syscallX(dlopenABI0, uintptr(unsafe.Pointer(p)), uintptr(mode), 0)
 	if handle <= 0 {
 		return nil, lastError()
 	}
@@ -159,7 +159,8 @@ func (d *Dylib) Lookup(name string) (uintptr, error) {
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	ret := dlsym(uintptr(d.Handle), p)
+	ret, _, _ := syscall_syscallX(dlsymABI0, uintptr(d.Handle), uintptr(unsafe.Pointer(p)), 0)
+	runtime.KeepAlive(p)
 	// We must check dlerrgl.go
 	//gl.sor because symbol could be NULL.
 	if err = lastError(); err != nil {
@@ -188,7 +189,7 @@ func (d *Dylib) Close() (err error) {
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	ret := dlclose(uintptr(d.Handle))
+	ret, _, _ := syscall_syscallX(dlcloseABI0, uintptr(d.Handle), 0, 0)
 	if ret != 0 {
 		err = lastError()
 	}
@@ -206,7 +207,7 @@ func (d *Dylib) Close() (err error) {
 // See dlerror(3).
 //
 func lastError() error {
-	ret := dlerror()
+	ret, _, _ := syscall_syscallX(dlerrorABI0, 0, 0, 0)
 	if ret != 0 {
 		s := gostring(ret)
 		// TODO export error vars by known string suffixes.

dl_darwin_amd64_test.s

@@ -4,7 +4,6 @@ import (
 	"fmt"
 	"runtime"
 	"testing"
-	"unsafe"
 )
 
 func getLibc() string {
@@ -18,17 +17,14 @@ func getLibc() string {
 	}
 }
 
-var _malloc uintptr // pointer to malloc function
-
-func libc_malloc(uintptr) unsafe.Pointer
-
 func TestDL(t *testing.T) {
 	var err error
 	libc, err := Open(getLibc(), ScopeGlobal)
 	if err != nil {
 		t.Fatal(err)
 		return
 	}
+	var _malloc uintptr
 	_malloc, err = libc.Lookup("malloc")
 	if err != nil {
 		t.Fatal(err)
@@ -38,7 +34,7 @@ func TestDL(t *testing.T) {
 		t.Failed()
 	}
 	const MallocSize = 5
-	if libc_malloc(MallocSize) == nil {
+	if ret, _, _ := syscall_syscallX(_malloc, MallocSize, 0, 0); ret == 0 {
 		t.Failed()
 	}
 	_, err = libc.Lookup("UnknownFunctionName")

dl_darwin_arm64_test.s

@@ -1,11 +1,15 @@
 package dl
 
 import (
+	"reflect"
 	"strings"
 	"syscall"
 	"unsafe"
 )
 
+//go:linkname syscall_syscallX syscall.syscallX
+func syscall_syscallX(fn, a1, a2, a3 uintptr) (r1, r2, err uintptr) // from runtime/sys_darwin_64.go
+
 func cstring(s string) (*byte, error) {
 	if strings.IndexByte(s, 0) != -1 {
 		return nil, syscall.EINVAL
@@ -23,3 +27,7 @@ func gostring(p uintptr) (ret string) {
 	}
 	return
 }
+
+func funcPC(f interface{}) uintptr {
+	return reflect.ValueOf(f).Pointer()
+}

dl_test.go

@@ -0,0 +1,14 @@
+package dl
+
+var dlopenABI0 uintptr
+var dlsymABI0 uintptr
+var dlerrorABI0 uintptr
+var dlcloseABI0 uintptr
+
+func dlopen(path *byte, mode int) (ret uintptr)
+
+func dlerror() (ret uintptr)
+
+func dlclose(handle uintptr) (ret int)
+
+func dlsym(handle uintptr, symbol *byte) (ret uintptr)

libc.go

@@ -0,0 +1,30 @@
+#include "textflag.h"
+
+//func dlopen(path *byte, mode int) (ret uintptr)
+GLOBL ·dlopenABI0(SB), NOPTR|RODATA, $8
+DATA ·dlopenABI0(SB)/8, $·dlopen(SB)
+TEXT ·dlopen(SB), NOSPLIT, $0-0
+   	JMP	_dlopen(SB)
+   	RET
+
+//func dlerror() (ret uintptr)
+GLOBL ·dlerrorABI0(SB), NOPTR|RODATA, $8
+DATA ·dlerrorABI0(SB)/8, $·dlerror(SB)
+TEXT ·dlerror(SB), NOSPLIT, $0-0
+	JMP _dlerror(SB)
+	RET
+
+//func dlclose(handle uintptr) (ret int)
+GLOBL ·dlcloseABI0(SB), NOPTR|RODATA, $8
+DATA ·dlcloseABI0(SB)/8, $·dlclose(SB)
+TEXT ·dlclose(SB), NOSPLIT, $0-0
+	JMP _dlclose(SB)
+	RET
+
+//func dlsym(handle uintptr, symbol *byte) (ret uintptr)
+GLOBL ·dlsymABI0(SB), NOPTR|RODATA, $8
+DATA ·dlsymABI0(SB)/8, $·dlsym(SB)
+TEXT ·dlsym(SB), NOSPLIT, $0-0
+	JMP _dlsym(SB)
+	RET
+