Merge pull request #45 from achilleasa/enable-support-for-defer

Enable support for defer

src/arch/x86_64/asm/rt0_64.s

@@ -95,6 +95,7 @@ _rt0_64_setup_go_runtime_structs:
 	; Link m0 to the g0
 	extern runtime.m0
 	mov rbx, runtime.m0
+	mov qword [rbx+GO_M_CURG], rsi     ; m.curg = g0
 	mov qword [rbx+GO_M_G0], rsi       ; m.g0 = g0
 	mov qword [rsi+GO_G_M], rbx        ; g.m = m
 

src/gopheros/kernel/goruntime/bootstrap.go

@@ -21,6 +21,7 @@ var (
 	typeLinksInitFn      = typeLinksInit
 	itabsInitFn          = itabsInit
 	initGoPackagesFn     = initGoPackages
+	procResizeFn         = procResize
 
 	// A seed for the pseudo-random number generator used by getRandomData
 	prngSeed = 0xdeadc0de
@@ -44,6 +45,9 @@ func mallocInit()
 //go:linkname mSysStatInc runtime.mSysStatInc
 func mSysStatInc(*uint64, uintptr)
 
+//go:linkname procResize runtime.procresize
+func procResize(int32) uintptr
+
 // initGoPackages is an alias to main.init which recursively calls the init()
 // methods in all imported packages. Unless this function is called, things like
 // package errors will not be properly initialized causing various problems when
@@ -184,11 +188,20 @@ func Init() *kernel.Error {
 	typeLinksInitFn() // uses maps, activeModules
 	itabsInitFn()     // uses activeModules
 
+	// Set processor count to 1. This initializes the p pointer in the
+	// currently active m allowing the kernel to register defer functions
+	SetCPUCount(1)
+
 	initGoPackagesFn()
 
 	return nil
 }
 
+// SetCPUCount registers the number of available CPUs with the Go runtime.
+func SetCPUCount(numCPUs int32) {
+	procResizeFn(numCPUs)
+}
+
 func init() {
 	// Dummy calls so the compiler does not optimize away the functions in
 	// this file.

src/gopheros/kernel/goruntime/bootstrap_test.go

@@ -267,6 +267,7 @@ func TestInit(t *testing.T) {
 		typeLinksInitFn = typeLinksInit
 		itabsInitFn = itabsInit
 		initGoPackagesFn = initGoPackages
+		procResizeFn = procResize
 	}()
 
 	mallocInitFn = func() {}
@@ -275,7 +276,7 @@ func TestInit(t *testing.T) {
 	typeLinksInitFn = func() {}
 	itabsInitFn = func() {}
 	initGoPackagesFn = func() {}
-
+	procResizeFn = func(_ int32) uintptr { return 0 }
 	if err := Init(); err != nil {
 		t.Fatal(t)
 	}

src/gopheros/kernel/kmain/kmain.go

@@ -39,10 +39,13 @@ func Kmain(multibootInfoPtr, kernelStart, kernelEnd, kernelPageOffset uintptr) {
 		panic(err)
 	}
 
+	// After goruntime.Init returns we can safely use defer
+	defer func() {
+		// Use kfmt.Panic instead of panic to prevent the compiler from
+		// treating kernel.Panic as dead-code and eliminating it.
+		kfmt.Panic(errKmainReturned)
+	}()
+
 	// Detect and initialize hardware
 	hal.DetectHardware()
-
-	// Use kfmt.Panic instead of panic to prevent the compiler from
-	// treating kernel.Panic as dead-code and eliminating it.
-	kfmt.Panic(errKmainReturned)
 }