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https://github.com/taigrr/gopher-os
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vmm: switch exception handling to use the new gate package
This commit is contained in:
Achilleas Anagnostopoulos
parent
7b12fbd940
commit
7deeab3cbc
@ -2,12 +2,24 @@ package vmm
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import (
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"gopheros/kernel"
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"gopheros/kernel/irq"
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"gopheros/kernel/gate"
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"gopheros/kernel/kfmt"
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"gopheros/kernel/mm"
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)
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func pageFaultHandler(errorCode uint64, frame *irq.Frame, regs *irq.Regs) {
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var (
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// handleInterruptFn is used by tests.
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handleInterruptFn = gate.HandleInterrupt
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)
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func installFaultHandlers() {
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handleInterruptFn(gate.PageFaultException, 0, pageFaultHandler)
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handleInterruptFn(gate.GPFException, 0, generalProtectionFaultHandler)
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}
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// pageFaultHandler is invoked when a PDT or PDT-entry is not present or when a
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// RW protection check fails.
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func pageFaultHandler(regs *gate.Registers) {
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var (
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faultAddress = uintptr(readCR2Fn())
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faultPage = mm.PageFromAddress(faultAddress)
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@ -35,9 +47,9 @@ func pageFaultHandler(errorCode uint64, frame *irq.Frame, regs *irq.Regs) {
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)
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if copy, err = mm.AllocFrame(); err != nil {
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nonRecoverablePageFault(faultAddress, errorCode, frame, regs, err)
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nonRecoverablePageFault(faultAddress, regs, err)
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} else if tmpPage, err = mapTemporaryFn(copy); err != nil {
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nonRecoverablePageFault(faultAddress, errorCode, frame, regs, err)
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nonRecoverablePageFault(faultAddress, regs, err)
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} else {
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// Copy page contents, mark as RW and remove CoW flag
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kernel.Memcopy(faultPage.Address(), tmpPage.Address(), mm.PageSize)
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@ -55,44 +67,46 @@ func pageFaultHandler(errorCode uint64, frame *irq.Frame, regs *irq.Regs) {
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}
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}
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nonRecoverablePageFault(faultAddress, errorCode, frame, regs, errUnrecoverableFault)
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nonRecoverablePageFault(faultAddress, regs, errUnrecoverableFault)
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}
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func nonRecoverablePageFault(faultAddress uintptr, errorCode uint64, frame *irq.Frame, regs *irq.Regs, err *kernel.Error) {
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// generalProtectionFaultHandler is invoked for various reasons:
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// - segment errors (privilege, type or limit violations)
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// - executing privileged instructions outside ring-0
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// - attempts to access reserved or unimplemented CPU registers
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func generalProtectionFaultHandler(regs *gate.Registers) {
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kfmt.Printf("\nGeneral protection fault while accessing address: 0x%x\n", readCR2Fn())
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kfmt.Printf("Registers:\n")
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regs.DumpTo(kfmt.GetOutputSink())
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// TODO: Revisit this when user-mode tasks are implemented
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panic(errUnrecoverableFault)
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}
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func nonRecoverablePageFault(faultAddress uintptr, regs *gate.Registers, err *kernel.Error) {
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kfmt.Printf("\nPage fault while accessing address: 0x%16x\nReason: ", faultAddress)
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switch {
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case errorCode == 0:
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case regs.Info == 0:
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kfmt.Printf("read from non-present page")
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case errorCode == 1:
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case regs.Info == 1:
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kfmt.Printf("page protection violation (read)")
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case errorCode == 2:
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case regs.Info == 2:
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kfmt.Printf("write to non-present page")
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case errorCode == 3:
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case regs.Info == 3:
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kfmt.Printf("page protection violation (write)")
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case errorCode == 4:
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case regs.Info == 4:
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kfmt.Printf("page-fault in user-mode")
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case errorCode == 8:
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case regs.Info == 8:
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kfmt.Printf("page table has reserved bit set")
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case errorCode == 16:
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case regs.Info == 16:
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kfmt.Printf("instruction fetch")
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default:
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kfmt.Printf("unknown")
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}
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kfmt.Printf("\n\nRegisters:\n")
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regs.Print()
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frame.Print()
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regs.DumpTo(kfmt.GetOutputSink())
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// TODO: Revisit this when user-mode tasks are implemented
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panic(err)
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}
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func generalProtectionFaultHandler(_ uint64, frame *irq.Frame, regs *irq.Regs) {
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kfmt.Printf("\nGeneral protection fault while accessing address: 0x%x\n", readCR2Fn())
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kfmt.Printf("Registers:\n")
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regs.Print()
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frame.Print()
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// TODO: Revisit this when user-mode tasks are implemented
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panic(errUnrecoverableFault)
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}
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@ -5,7 +5,7 @@ import (
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"fmt"
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"gopheros/kernel"
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"gopheros/kernel/cpu"
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"gopheros/kernel/irq"
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"gopheros/kernel/gate"
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"gopheros/kernel/kfmt"
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"gopheros/kernel/mm"
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"strings"
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@ -15,8 +15,7 @@ import (
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func TestRecoverablePageFault(t *testing.T) {
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var (
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frame irq.Frame
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regs irq.Regs
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regs gate.Registers
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pageEntry pageTableEntry
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origPage = make([]byte, mm.PageSize)
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clonedPage = make([]byte, mm.PageSize)
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@ -91,7 +90,8 @@ func TestRecoverablePageFault(t *testing.T) {
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pageEntry = 0
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pageEntry.SetFlags(spec.pteFlags)
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pageFaultHandler(2, &frame, ®s)
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regs.Info = 2
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pageFaultHandler(®s)
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})
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}
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@ -141,8 +141,7 @@ func TestNonRecoverablePageFault(t *testing.T) {
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}
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var (
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regs irq.Regs
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frame irq.Frame
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regs gate.Registers
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buf bytes.Buffer
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)
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@ -156,7 +155,8 @@ func TestNonRecoverablePageFault(t *testing.T) {
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}
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}()
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nonRecoverablePageFault(0xbadf00d000, spec.errCode, &frame, ®s, errUnrecoverableFault)
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regs.Info = spec.errCode
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nonRecoverablePageFault(0xbadf00d000, ®s, errUnrecoverableFault)
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if got := buf.String(); !strings.Contains(got, spec.expReason) {
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t.Errorf("expected reason %q; got output:\n%q", spec.expReason, got)
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}
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@ -169,10 +169,7 @@ func TestGPFHandler(t *testing.T) {
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readCR2Fn = cpu.ReadCR2
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}()
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var (
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regs irq.Regs
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frame irq.Frame
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)
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var regs gate.Registers
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readCR2Fn = func() uint64 {
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return 0xbadf00d000
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@ -184,5 +181,5 @@ func TestGPFHandler(t *testing.T) {
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}
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}()
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generalProtectionFaultHandler(0, &frame, ®s)
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generalProtectionFaultHandler(®s)
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}
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@ -3,14 +3,12 @@ package vmm
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import (
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"gopheros/kernel"
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"gopheros/kernel/cpu"
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"gopheros/kernel/irq"
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"gopheros/kernel/mm"
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)
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var (
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// the following functions are mocked by tests and are automatically
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// inlined by the compiler.
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handleExceptionWithCodeFn = irq.HandleExceptionWithCode
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readCR2Fn = cpu.ReadCR2
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translateFn = Translate
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@ -24,13 +22,10 @@ func Init(kernelPageOffset uintptr) *kernel.Error {
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return err
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}
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if err := reserveZeroedFrame(); err != nil {
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return err
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}
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// Install arch-specific handlers for vmm-related faults.
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installFaultHandlers()
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handleExceptionWithCodeFn(irq.PageFaultException, pageFaultHandler)
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handleExceptionWithCodeFn(irq.GPFException, generalProtectionFaultHandler)
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return nil
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return reserveZeroedFrame()
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}
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// reserveZeroedFrame reserves a physical frame to be used together with
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@ -3,7 +3,7 @@ package vmm
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import (
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"gopheros/kernel"
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"gopheros/kernel/cpu"
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"gopheros/kernel/irq"
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"gopheros/kernel/gate"
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"gopheros/kernel/mm"
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"gopheros/multiboot"
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"testing"
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@ -18,7 +18,7 @@ func TestInit(t *testing.T) {
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translateFn = Translate
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mapTemporaryFn = MapTemporary
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unmapFn = Unmap
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handleExceptionWithCodeFn = irq.HandleExceptionWithCode
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handleInterruptFn = gate.HandleInterrupt
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}()
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// reserve space for an allocated page
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@ -42,7 +42,7 @@ func TestInit(t *testing.T) {
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switchPDTFn = func(_ uintptr) {}
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unmapFn = func(p mm.Page) *kernel.Error { return nil }
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mapTemporaryFn = func(f mm.Frame) (mm.Page, *kernel.Error) { return mm.Page(f), nil }
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handleExceptionWithCodeFn = func(_ irq.ExceptionNum, _ irq.ExceptionHandlerWithCode) {}
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handleInterruptFn = func(_ gate.InterruptNumber, _ uint8, _ func(*gate.Registers)) {}
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if err := Init(0); err != nil {
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t.Fatal(err)
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@ -92,7 +92,7 @@ func TestInit(t *testing.T) {
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switchPDTFn = func(_ uintptr) {}
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unmapFn = func(p mm.Page) *kernel.Error { return nil }
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mapTemporaryFn = func(f mm.Frame) (mm.Page, *kernel.Error) { return mm.Page(f), nil }
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handleExceptionWithCodeFn = func(_ irq.ExceptionNum, _ irq.ExceptionHandlerWithCode) {}
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handleInterruptFn = func(_ gate.InterruptNumber, _ uint8, _ func(*gate.Registers)) {}
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if err := Init(0); err != expErr {
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t.Fatalf("expected error: %v; got %v", expErr, err)
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@ -112,7 +112,7 @@ func TestInit(t *testing.T) {
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switchPDTFn = func(_ uintptr) {}
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unmapFn = func(p mm.Page) *kernel.Error { return nil }
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mapTemporaryFn = func(f mm.Frame) (mm.Page, *kernel.Error) { return mm.Page(f), expErr }
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handleExceptionWithCodeFn = func(_ irq.ExceptionNum, _ irq.ExceptionHandlerWithCode) {}
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handleInterruptFn = func(_ gate.InterruptNumber, _ uint8, _ func(*gate.Registers)) {}
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if err := Init(0); err != expErr {
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t.Fatalf("expected error: %v; got %v", expErr, err)
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