Merge pull request #40 from achilleasa/map-vga-text-fb

Map vga text console framebuffer

src/gopheros/device/video/console/probe.go

@@ -1,9 +1,15 @@
 package console
 
-import "gopheros/device"
-import "gopheros/kernel/hal/multiboot"
+import (
+	"gopheros/device"
+	"gopheros/kernel/cpu"
+	"gopheros/kernel/hal/multiboot"
+	"gopheros/kernel/mem/vmm"
+)
 
 var (
+	mapRegionFn          = vmm.MapRegion
+	portWriteByteFn      = cpu.PortWriteByte
 	getFramebufferInfoFn = multiboot.GetFramebufferInfo
 
 	// ProbeFuncs is a slice of device probe functions that is used by

src/gopheros/device/video/console/vga_text.go

@@ -3,16 +3,17 @@ package console
 import (
 	"gopheros/device"
 	"gopheros/kernel"
-	"gopheros/kernel/cpu"
 	"gopheros/kernel/hal/multiboot"
+	"gopheros/kernel/kfmt"
+	"gopheros/kernel/mem"
+	"gopheros/kernel/mem/pmm"
+	"gopheros/kernel/mem/vmm"
 	"image/color"
 	"io"
 	"reflect"
 	"unsafe"
 )
 
-var portWriteByteFn = cpu.PortWriteByte
-
 // VgaTextConsole implements an EGA-compatible 80x25 text console using VGA
 // mode 0x3. The console supports the default 16 EGA colors which can be
 // overridden using the SetPaletteColor method.
@@ -28,7 +29,8 @@ type VgaTextConsole struct {
 	width  uint32
 	height uint32
 
-	fb []uint16
+	fbPhysAddr uintptr
+	fb         []uint16
 
 	palette   color.Palette
 	defaultFg uint8
@@ -40,15 +42,10 @@ type VgaTextConsole struct {
 // framebuffer mapped to fbPhysAddr.
 func NewVgaTextConsole(columns, rows uint32, fbPhysAddr uintptr) *VgaTextConsole {
 	return &VgaTextConsole{
-		width:     columns,
-		height:    rows,
-		clearChar: uint16(' '),
-		// overlay a 16bit slice over the fbPhysAddr
-		fb: *(*[]uint16)(unsafe.Pointer(&reflect.SliceHeader{
-			Len:  int(columns * rows),
-			Cap:  int(columns * rows),
-			Data: fbPhysAddr,
-		})),
+		width:      columns,
+		height:     rows,
+		fbPhysAddr: fbPhysAddr,
+		clearChar:  uint16(' '),
 		palette: color.Palette{
 			color.RGBA{R: 0, G: 0, B: 1},       /* black */
 			color.RGBA{R: 0, G: 0, B: 128},     /* blue */
@@ -198,7 +195,29 @@ func (cons *VgaTextConsole) DriverVersion() (uint16, uint16, uint16) {
 }
 
 // DriverInit initializes this driver.
-func (cons *VgaTextConsole) DriverInit(_ io.Writer) *kernel.Error { return nil }
+func (cons *VgaTextConsole) DriverInit(w io.Writer) *kernel.Error {
+	// Map the framebuffer so we can write to it
+	fbSize := mem.Size(cons.width * cons.height * 2)
+	fbPage, err := mapRegionFn(
+		pmm.Frame(cons.fbPhysAddr>>mem.PageShift),
+		fbSize,
+		vmm.FlagPresent|vmm.FlagRW,
+	)
+
+	if err != nil {
+		return err
+	}
+
+	cons.fb = *(*[]uint16)(unsafe.Pointer(&reflect.SliceHeader{
+		Len:  int(fbSize >> 1),
+		Cap:  int(fbSize >> 1),
+		Data: fbPage.Address(),
+	}))
+
+	kfmt.Fprintf(w, "mapped framebuffer to 0x%x\n", fbPage.Address())
+
+	return nil
+}
 
 // probeForVgaTextConsole checks for the presence of a vga text console.
 func probeForVgaTextConsole() device.Driver {

src/gopheros/device/video/console/vga_text_test.go

@@ -2,8 +2,12 @@ package console
 
 import (
 	"gopheros/device"
+	"gopheros/kernel"
 	"gopheros/kernel/cpu"
 	"gopheros/kernel/hal/multiboot"
+	"gopheros/kernel/mem"
+	"gopheros/kernel/mem/pmm"
+	"gopheros/kernel/mem/vmm"
 	"image/color"
 	"testing"
 	"unsafe"
@@ -63,6 +67,7 @@ func TestVgaTextFill(t *testing.T) {
 
 	fb := make([]uint16, 80*25)
 	cons := NewVgaTextConsole(80, 25, uintptr(unsafe.Pointer(&fb[0])))
+	cons.fb = fb
 	cw, ch := cons.Dimensions()
 
 	testPat := uint16(0xDEAD)
@@ -101,6 +106,7 @@ nextSpec:
 func TestVgaTextScroll(t *testing.T) {
 	fb := make([]uint16, 80*25)
 	cons := NewVgaTextConsole(80, 25, uintptr(unsafe.Pointer(&fb[0])))
+	cons.fb = fb
 	cw, ch := cons.Dimensions()
 
 	t.Run("up", func(t *testing.T) {
@@ -176,6 +182,7 @@ func TestVgaTextScroll(t *testing.T) {
 func TestVgaTextWrite(t *testing.T) {
 	fb := make([]uint16, 80*25)
 	cons := NewVgaTextConsole(80, 25, uintptr(unsafe.Pointer(&fb[0])))
+	cons.fb = fb
 	defaultFg, defaultBg := cons.DefaultColors()
 
 	t.Run("off-screen", func(t *testing.T) {
@@ -309,12 +316,11 @@ func TestVgaTextSetPaletteColor(t *testing.T) {
 }
 
 func TestVgaTextDriverInterface(t *testing.T) {
+	defer func() {
+		mapRegionFn = vmm.MapRegion
+	}()
 	var dev device.Driver = NewVgaTextConsole(80, 25, 0)
 
-	if err := dev.DriverInit(nil); err != nil {
-		t.Fatal(err)
-	}
-
 	if dev.DriverName() == "" {
 		t.Fatal("DriverName() returned an empty string")
 	}
@@ -322,6 +328,27 @@ func TestVgaTextDriverInterface(t *testing.T) {
 	if major, minor, patch := dev.DriverVersion(); major+minor+patch == 0 {
 		t.Fatal("DriverVersion() returned an invalid version number")
 	}
+
+	t.Run("init success", func(t *testing.T) {
+		mapRegionFn = func(_ pmm.Frame, _ mem.Size, _ vmm.PageTableEntryFlag) (vmm.Page, *kernel.Error) {
+			return 0xb8000, nil
+		}
+
+		if err := dev.DriverInit(nil); err != nil {
+			t.Fatal(err)
+		}
+	})
+
+	t.Run("init fail", func(t *testing.T) {
+		expErr := &kernel.Error{Module: "test", Message: "something went wrong"}
+		mapRegionFn = func(_ pmm.Frame, _ mem.Size, _ vmm.PageTableEntryFlag) (vmm.Page, *kernel.Error) {
+			return 0, expErr
+		}
+
+		if err := dev.DriverInit(nil); err != expErr {
+			t.Fatalf("expected error: %v; got %v", expErr, err)
+		}
+	})
 }
 
 func TestVgaTextProbe(t *testing.T) {

src/gopheros/kernel/mem/vmm/map.go

@@ -47,6 +47,8 @@ var (
 	// which will cause a fault if called in user-mode.
 	flushTLBEntryFn = cpu.FlushTLBEntry
 
+	earlyReserveRegionFn = EarlyReserveRegion
+
 	errNoHugePageSupport           = &kernel.Error{Module: "vmm", Message: "huge pages are not supported"}
 	errAttemptToRWMapReservedFrame = &kernel.Error{Module: "vmm", Message: "reserved blank frame cannot be mapped with a RW flag"}
 )
@@ -105,6 +107,29 @@ func Map(page Page, frame pmm.Frame, flags PageTableEntryFlag) *kernel.Error {
 	return err
 }
 
+// MapRegion establishes a mapping to the physical memory region which starts
+// at the given frame and ends at frame + pages(size). The size argument is
+// always rounded up to the nearest page boundary. MapRegion reserves the next
+// available region in the active virtual address space, establishes the
+// mapping and returns back the Page that corresponds to the region start.
+func MapRegion(frame pmm.Frame, size mem.Size, flags PageTableEntryFlag) (Page, *kernel.Error) {
+	// Reserve next free block in the address space
+	size = (size + (mem.PageSize - 1)) & ^(mem.PageSize - 1)
+	startPage, err := earlyReserveRegionFn(size)
+	if err != nil {
+		return 0, err
+	}
+
+	pageCount := size >> mem.PageShift
+	for page := PageFromAddress(startPage); pageCount > 0; pageCount, page, frame = pageCount-1, page+1, frame+1 {
+		if err := mapFn(page, frame, flags); err != nil {
+			return 0, err
+		}
+	}
+
+	return PageFromAddress(startPage), nil
+}
+
 // MapTemporary establishes a temporary RW mapping of a physical memory frame
 // to a fixed virtual address overwriting any previous mapping. The temporary
 // mapping mechanism is primarily used by the kernel to access and initialize

src/gopheros/kernel/mem/vmm/map_test.go

@@ -97,6 +97,73 @@ func TestMapTemporaryAmd64(t *testing.T) {
 	}
 }
 
+func TestMapRegion(t *testing.T) {
+	defer func() {
+		mapFn = Map
+		earlyReserveRegionFn = EarlyReserveRegion
+	}()
+
+	t.Run("success", func(t *testing.T) {
+		mapCallCount := 0
+		mapFn = func(_ Page, _ pmm.Frame, flags PageTableEntryFlag) *kernel.Error {
+			mapCallCount++
+			return nil
+		}
+
+		earlyReserveRegionCallCount := 0
+		earlyReserveRegionFn = func(_ mem.Size) (uintptr, *kernel.Error) {
+			earlyReserveRegionCallCount++
+			return 0xf00, nil
+		}
+
+		if _, err := MapRegion(pmm.Frame(0xdf0000), 4097, FlagPresent|FlagRW); err != nil {
+			t.Fatal(err)
+		}
+
+		if exp := 2; mapCallCount != exp {
+			t.Errorf("expected Map to be called %d time(s); got %d", exp, mapCallCount)
+		}
+
+		if exp := 1; earlyReserveRegionCallCount != exp {
+			t.Errorf("expected EarlyReserveRegion to be called %d time(s); got %d", exp, earlyReserveRegionCallCount)
+		}
+	})
+
+	t.Run("EarlyReserveRegion fails", func(t *testing.T) {
+		expErr := &kernel.Error{Module: "test", Message: "out of address space"}
+
+		earlyReserveRegionFn = func(_ mem.Size) (uintptr, *kernel.Error) {
+			return 0, expErr
+		}
+
+		if _, err := MapRegion(pmm.Frame(0xdf0000), 128000, FlagPresent|FlagRW); err != expErr {
+			t.Fatalf("expected error: %v; got %v", expErr, err)
+		}
+	})
+
+	t.Run("Map fails", func(t *testing.T) {
+		expErr := &kernel.Error{Module: "test", Message: "map failed"}
+
+		earlyReserveRegionCallCount := 0
+		earlyReserveRegionFn = func(_ mem.Size) (uintptr, *kernel.Error) {
+			earlyReserveRegionCallCount++
+			return 0xf00, nil
+		}
+
+		mapFn = func(_ Page, _ pmm.Frame, flags PageTableEntryFlag) *kernel.Error {
+			return expErr
+		}
+
+		if _, err := MapRegion(pmm.Frame(0xdf0000), 128000, FlagPresent|FlagRW); err != expErr {
+			t.Fatalf("expected error: %v; got %v", expErr, err)
+		}
+
+		if exp := 1; earlyReserveRegionCallCount != exp {
+			t.Errorf("expected EarlyReserveRegion to be called %d time(s); got %d", exp, earlyReserveRegionCallCount)
+		}
+	})
+}
+
 func TestMapTemporaryErrorsAmd64(t *testing.T) {
 	if runtime.GOARCH != "amd64" {
 		t.Skip("test requires amd64 runtime; skipping")