Merge pull request #35 from achilleasa/bootstrap-interfaces-and-map-primitive

Enable support for interfaces and the map primitive

kernel/goruntime/bootstrap.go

@@ -16,8 +16,27 @@ var (
 	earlyReserveRegionFn = vmm.EarlyReserveRegion
 	frameAllocFn         = allocator.AllocFrame
 	mallocInitFn         = mallocInit
+	algInitFn            = algInit
+	modulesInitFn        = modulesInit
+	typeLinksInitFn      = typeLinksInit
+	itabsInitFn          = itabsInit
+
+	// A seed for the pseudo-random number generator used by getRandomData
+	prngSeed = 0xdeadc0de
 )
 
+//go:linkname algInit runtime.alginit
+func algInit()
+
+//go:linkname modulesInit runtime.modulesinit
+func modulesInit()
+
+//go:linkname typeLinksInit runtime.typelinksinit
+func typeLinksInit()
+
+//go:linkname itabsInit runtime.itabsinit
+func itabsInit()
+
 //go:linkname mallocInit runtime.mallocinit
 func mallocInit()
 
@@ -121,11 +140,30 @@ func nanotime() uint64 {
 	return 1
 }
 
+// getRandomData populates the given slice with random data. The implementation
+// is the runtime package reads a random stream from /dev/random but since this
+// is not available, we use a prng instead.
+//
+//go:redirect-from runtime.getRandomData
+func getRandomData(r []byte) {
+	for i := 0; i < len(r); i++ {
+		prngSeed = (prngSeed * 58321) + 11113
+		r[i] = byte((prngSeed >> 16) & 255)
+	}
+}
+
 // Init enables support for various Go runtime features. After a call to init
 // the following runtime features become available for use:
 //  - heap memory allocation (new, make e.t.c)
+//  - map primitives
+//  - interfaces
 func Init() *kernel.Error {
 	mallocInitFn()
+	algInitFn()       // setup hash implementation for map keys
+	modulesInitFn()   // provides activeModules
+	typeLinksInitFn() // uses maps, activeModules
+	itabsInitFn()     // uses activeModules
+
 	return nil
 }
 
@@ -141,5 +179,6 @@ func init() {
 	sysReserve(zeroPtr, 0, &reserved)
 	sysMap(zeroPtr, 0, reserved, &stat)
 	sysAlloc(0, &stat)
+	getRandomData(nil)
 	stat = nanotime()
 }

kernel/goruntime/bootstrap_test.go

@@ -1,6 +1,7 @@
 package goruntime
 
 import (
+	"reflect"
 	"testing"
 	"unsafe"
 
@@ -236,11 +237,32 @@ func TestSysAlloc(t *testing.T) {
 	})
 }
 
+func TestGetRandomData(t *testing.T) {
+	sample1 := make([]byte, 128)
+	sample2 := make([]byte, 128)
+
+	getRandomData(sample1)
+	getRandomData(sample2)
+
+	if reflect.DeepEqual(sample1, sample2) {
+		t.Fatal("expected getRandomData to return different values for each invocation")
+	}
+}
+
 func TestInit(t *testing.T) {
 	defer func() {
 		mallocInitFn = mallocInit
+		algInitFn = algInit
+		modulesInitFn = modulesInit
+		typeLinksInitFn = typeLinksInit
+		itabsInitFn = itabsInit
 	}()
+
 	mallocInitFn = func() {}
+	algInitFn = func() {}
+	modulesInitFn = func() {}
+	typeLinksInitFn = func() {}
+	itabsInitFn = func() {}
 
 	if err := Init(); err != nil {
 		t.Fatal(t)