mirror of
https://github.com/taigrr/gopher-os
synced 2025-01-18 04:43:13 -08:00
Setup a more granular PDT based on the ELF image section addresses
This commit is contained in:
Achilleas Anagnostopoulos
parent
cc4364f55c
commit
6195f3fc3b
@ -33,6 +33,7 @@ func Kmain(multibootInfoPtr, kernelStart, kernelEnd, kernelPageOffset uintptr) {
|
||||
var err *kernel.Error
|
||||
if err = allocator.Init(kernelStart, kernelEnd); err != nil {
|
||||
panic(err)
|
||||
} else if err = vmm.Init(kernelPageOffset); err != nil {
|
||||
panic(err)
|
||||
} else if err = goruntime.Init(); err != nil {
|
||||
panic(err)
|
||||
|
||||
@ -3,10 +3,12 @@ package vmm
|
||||
import (
|
||||
"gopheros/kernel"
|
||||
"gopheros/kernel/cpu"
|
||||
"gopheros/kernel/hal/multiboot"
|
||||
"gopheros/kernel/irq"
|
||||
"gopheros/kernel/kfmt"
|
||||
"gopheros/kernel/mem"
|
||||
"gopheros/kernel/mem/pmm"
|
||||
"unsafe"
|
||||
)
|
||||
|
||||
var (
|
||||
@ -18,6 +20,8 @@ var (
|
||||
// inlined by the compiler.
|
||||
handleExceptionWithCodeFn = irq.HandleExceptionWithCode
|
||||
readCR2Fn = cpu.ReadCR2
|
||||
translateFn = Translate
|
||||
visitElfSectionsFn = multiboot.VisitElfSections
|
||||
|
||||
errUnrecoverableFault = &kernel.Error{Module: "vmm", Message: "page/gpf fault"}
|
||||
)
|
||||
@ -142,9 +146,13 @@ func reserveZeroedFrame() *kernel.Error {
|
||||
return nil
|
||||
}
|
||||
|
||||
// Init initializes the vmm system and installs paging-related exception
|
||||
// handlers.
|
||||
func Init() *kernel.Error {
|
||||
// Init initializes the vmm system, creates a granular PDT for the kernel and
|
||||
// installs paging-related exception handlers.
|
||||
func Init(kernelPageOffset uintptr) *kernel.Error {
|
||||
if err := setupPDTForKernel(kernelPageOffset); err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
if err := reserveZeroedFrame(); err != nil {
|
||||
return err
|
||||
}
|
||||
@ -153,3 +161,92 @@ func Init() *kernel.Error {
|
||||
handleExceptionWithCodeFn(irq.GPFException, generalProtectionFaultHandler)
|
||||
return nil
|
||||
}
|
||||
|
||||
// setupPDTForKernel queries the multiboot package for the ELF sections that
|
||||
// correspond to the loaded kernel image and establishes a new granular PDT for
|
||||
// the kernel's VMA using the appropriate flags (e.g. NX for data sections, RW
|
||||
// for writable sections e.t.c).
|
||||
func setupPDTForKernel(kernelPageOffset uintptr) *kernel.Error {
|
||||
var pdt PageDirectoryTable
|
||||
|
||||
// Allocate frame for the page directory and initialize it
|
||||
pdtFrame, err := frameAllocator()
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
if err = pdt.Init(pdtFrame); err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
// Query the ELF sections of the kernel image and establish mappings
|
||||
// for each one using the appropriate flags
|
||||
pageSizeMinus1 := uint64(mem.PageSize - 1)
|
||||
var visitor = func(_ string, secFlags multiboot.ElfSectionFlag, secAddress uintptr, secSize uint64) {
|
||||
// Bail out if we have encountered an error; also ignore sections
|
||||
// not using the kernel's VMA
|
||||
if err != nil || secAddress < kernelPageOffset {
|
||||
return
|
||||
}
|
||||
|
||||
flags := FlagPresent
|
||||
|
||||
if (secFlags & multiboot.ElfSectionExecutable) == 0 {
|
||||
flags |= FlagNoExecute
|
||||
}
|
||||
|
||||
if (secFlags & multiboot.ElfSectionWritable) != 0 {
|
||||
flags |= FlagRW
|
||||
}
|
||||
|
||||
// We assume that all sections are page-aligned by the linker script
|
||||
curPage := PageFromAddress(secAddress)
|
||||
curFrame := pmm.Frame((secAddress - kernelPageOffset) >> mem.PageShift)
|
||||
endFrame := curFrame + pmm.Frame(((secSize+pageSizeMinus1) & ^pageSizeMinus1)>>mem.PageShift)
|
||||
for ; curFrame < endFrame; curFrame, curPage = curFrame+1, curPage+1 {
|
||||
if err = pdt.Map(curPage, curFrame, flags); err != nil {
|
||||
return
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// Use the noescape hack to prevent the compiler from leaking the visitor
|
||||
// function literal to the heap.
|
||||
visitElfSectionsFn(
|
||||
*(*multiboot.ElfSectionVisitor)(noEscape(unsafe.Pointer(&visitor))),
|
||||
)
|
||||
|
||||
// If an error occurred while maping the ELF sections bail out
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
// Ensure that any pages mapped by the memory allocator using
|
||||
// EarlyReserveRegion are copied to the new page directory.
|
||||
for rsvAddr := earlyReserveLastUsed; rsvAddr < tempMappingAddr; rsvAddr += uintptr(mem.PageSize) {
|
||||
page := PageFromAddress(rsvAddr)
|
||||
|
||||
frameAddr, err := translateFn(rsvAddr)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
if err = pdt.Map(page, pmm.Frame(frameAddr>>mem.PageShift), FlagPresent|FlagRW); err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
|
||||
// Activate the new PDT. After this point, the identify mapping for the
|
||||
// physical memory addresses where the kernel is loaded becomes invalid.
|
||||
pdt.Activate()
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
// noEscape hides a pointer from escape analysis. This function is copied over
|
||||
// from runtime/stubs.go
|
||||
//go:nosplit
|
||||
func noEscape(p unsafe.Pointer) unsafe.Pointer {
|
||||
x := uintptr(p)
|
||||
return unsafe.Pointer(x ^ 0)
|
||||
}
|
||||
|
||||
@ -5,6 +5,7 @@ import (
|
||||
"fmt"
|
||||
"gopheros/kernel"
|
||||
"gopheros/kernel/cpu"
|
||||
"gopheros/kernel/hal/multiboot"
|
||||
"gopheros/kernel/irq"
|
||||
"gopheros/kernel/kfmt"
|
||||
"gopheros/kernel/mem"
|
||||
@ -165,7 +166,7 @@ func TestNonRecoverablePageFault(t *testing.T) {
|
||||
}
|
||||
}
|
||||
|
||||
func TestGPtHandler(t *testing.T) {
|
||||
func TestGPFHandler(t *testing.T) {
|
||||
defer func() {
|
||||
readCR2Fn = cpu.ReadCR2
|
||||
}()
|
||||
@ -191,6 +192,9 @@ func TestGPtHandler(t *testing.T) {
|
||||
func TestInit(t *testing.T) {
|
||||
defer func() {
|
||||
frameAllocator = nil
|
||||
activePDTFn = cpu.ActivePDT
|
||||
switchPDTFn = cpu.SwitchPDT
|
||||
translateFn = Translate
|
||||
mapTemporaryFn = MapTemporary
|
||||
unmapFn = Unmap
|
||||
handleExceptionWithCodeFn = irq.HandleExceptionWithCode
|
||||
@ -199,6 +203,8 @@ func TestInit(t *testing.T) {
|
||||
// reserve space for an allocated page
|
||||
reservedPage := make([]byte, mem.PageSize)
|
||||
|
||||
multiboot.SetInfoPtr(uintptr(unsafe.Pointer(&emptyInfoData[0])))
|
||||
|
||||
t.Run("success", func(t *testing.T) {
|
||||
// fill page with junk
|
||||
for i := 0; i < len(reservedPage); i++ {
|
||||
@ -209,11 +215,15 @@ func TestInit(t *testing.T) {
|
||||
addr := uintptr(unsafe.Pointer(&reservedPage[0]))
|
||||
return pmm.Frame(addr >> mem.PageShift), nil
|
||||
})
|
||||
activePDTFn = func() uintptr {
|
||||
return uintptr(unsafe.Pointer(&reservedPage[0]))
|
||||
}
|
||||
switchPDTFn = func(_ uintptr) {}
|
||||
unmapFn = func(p Page) *kernel.Error { return nil }
|
||||
mapTemporaryFn = func(f pmm.Frame) (Page, *kernel.Error) { return Page(f), nil }
|
||||
handleExceptionWithCodeFn = func(_ irq.ExceptionNum, _ irq.ExceptionHandlerWithCode) {}
|
||||
|
||||
if err := Init(); err != nil {
|
||||
if err := Init(0); err != nil {
|
||||
t.Fatal(err)
|
||||
}
|
||||
|
||||
@ -225,15 +235,45 @@ func TestInit(t *testing.T) {
|
||||
}
|
||||
})
|
||||
|
||||
t.Run("setupPDT fails", func(t *testing.T) {
|
||||
expErr := &kernel.Error{Module: "test", Message: "out of memory"}
|
||||
|
||||
// Allow the PDT allocation to succeed and then return an error when
|
||||
// trying to allocate the blank fram
|
||||
SetFrameAllocator(func() (pmm.Frame, *kernel.Error) {
|
||||
return pmm.InvalidFrame, expErr
|
||||
})
|
||||
|
||||
if err := Init(0); err != expErr {
|
||||
t.Fatalf("expected error: %v; got %v", expErr, err)
|
||||
}
|
||||
})
|
||||
|
||||
t.Run("blank page allocation error", func(t *testing.T) {
|
||||
expErr := &kernel.Error{Module: "test", Message: "out of memory"}
|
||||
|
||||
SetFrameAllocator(func() (pmm.Frame, *kernel.Error) { return pmm.InvalidFrame, expErr })
|
||||
// Allow the PDT allocation to succeed and then return an error when
|
||||
// trying to allocate the blank fram
|
||||
var allocCount int
|
||||
SetFrameAllocator(func() (pmm.Frame, *kernel.Error) {
|
||||
defer func() { allocCount++ }()
|
||||
|
||||
if allocCount == 0 {
|
||||
addr := uintptr(unsafe.Pointer(&reservedPage[0]))
|
||||
return pmm.Frame(addr >> mem.PageShift), nil
|
||||
}
|
||||
|
||||
return pmm.InvalidFrame, expErr
|
||||
})
|
||||
activePDTFn = func() uintptr {
|
||||
return uintptr(unsafe.Pointer(&reservedPage[0]))
|
||||
}
|
||||
switchPDTFn = func(_ uintptr) {}
|
||||
unmapFn = func(p Page) *kernel.Error { return nil }
|
||||
mapTemporaryFn = func(f pmm.Frame) (Page, *kernel.Error) { return Page(f), nil }
|
||||
handleExceptionWithCodeFn = func(_ irq.ExceptionNum, _ irq.ExceptionHandlerWithCode) {}
|
||||
|
||||
if err := Init(); err != expErr {
|
||||
if err := Init(0); err != expErr {
|
||||
t.Fatalf("expected error: %v; got %v", expErr, err)
|
||||
}
|
||||
})
|
||||
@ -245,12 +285,207 @@ func TestInit(t *testing.T) {
|
||||
addr := uintptr(unsafe.Pointer(&reservedPage[0]))
|
||||
return pmm.Frame(addr >> mem.PageShift), nil
|
||||
})
|
||||
activePDTFn = func() uintptr {
|
||||
return uintptr(unsafe.Pointer(&reservedPage[0]))
|
||||
}
|
||||
switchPDTFn = func(_ uintptr) {}
|
||||
unmapFn = func(p Page) *kernel.Error { return nil }
|
||||
mapTemporaryFn = func(f pmm.Frame) (Page, *kernel.Error) { return Page(f), expErr }
|
||||
handleExceptionWithCodeFn = func(_ irq.ExceptionNum, _ irq.ExceptionHandlerWithCode) {}
|
||||
|
||||
if err := Init(); err != expErr {
|
||||
if err := Init(0); err != expErr {
|
||||
t.Fatalf("expected error: %v; got %v", expErr, err)
|
||||
}
|
||||
})
|
||||
}
|
||||
|
||||
func TestSetupPDTForKernel(t *testing.T) {
|
||||
defer func() {
|
||||
frameAllocator = nil
|
||||
activePDTFn = cpu.ActivePDT
|
||||
switchPDTFn = cpu.SwitchPDT
|
||||
translateFn = Translate
|
||||
mapFn = Map
|
||||
mapTemporaryFn = MapTemporary
|
||||
unmapFn = Unmap
|
||||
earlyReserveLastUsed = tempMappingAddr
|
||||
}()
|
||||
|
||||
// reserve space for an allocated page
|
||||
reservedPage := make([]byte, mem.PageSize)
|
||||
|
||||
multiboot.SetInfoPtr(uintptr(unsafe.Pointer(&emptyInfoData[0])))
|
||||
|
||||
t.Run("map kernel sections", func(t *testing.T) {
|
||||
defer func() { visitElfSectionsFn = multiboot.VisitElfSections }()
|
||||
|
||||
SetFrameAllocator(func() (pmm.Frame, *kernel.Error) {
|
||||
addr := uintptr(unsafe.Pointer(&reservedPage[0]))
|
||||
return pmm.Frame(addr >> mem.PageShift), nil
|
||||
})
|
||||
activePDTFn = func() uintptr {
|
||||
return uintptr(unsafe.Pointer(&reservedPage[0]))
|
||||
}
|
||||
switchPDTFn = func(_ uintptr) {}
|
||||
translateFn = func(_ uintptr) (uintptr, *kernel.Error) { return 0xbadf00d000, nil }
|
||||
mapTemporaryFn = func(f pmm.Frame) (Page, *kernel.Error) { return Page(f), nil }
|
||||
visitElfSectionsFn = func(v multiboot.ElfSectionVisitor) {
|
||||
v(".debug", 0, 0, uint64(mem.PageSize>>1)) // address < VMA; should be ignored
|
||||
v(".text", multiboot.ElfSectionExecutable, 0xbadc0ffee, uint64(mem.PageSize>>1))
|
||||
v(".data", multiboot.ElfSectionWritable, 0xbadc0ffee, uint64(mem.PageSize))
|
||||
v(".rodata", 0, 0xbadc0ffee, uint64(mem.PageSize<<1))
|
||||
}
|
||||
mapCount := 0
|
||||
mapFn = func(page Page, frame pmm.Frame, flags PageTableEntryFlag) *kernel.Error {
|
||||
defer func() { mapCount++ }()
|
||||
|
||||
var expFlags PageTableEntryFlag
|
||||
|
||||
switch mapCount {
|
||||
case 0:
|
||||
expFlags = FlagPresent
|
||||
case 1:
|
||||
expFlags = FlagPresent | FlagNoExecute | FlagRW
|
||||
case 2, 3:
|
||||
expFlags = FlagPresent | FlagNoExecute
|
||||
}
|
||||
|
||||
if (flags & expFlags) != expFlags {
|
||||
t.Errorf("[map call %d] expected flags to be %d; got %d", mapCount, expFlags, flags)
|
||||
}
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
if err := setupPDTForKernel(0x123); err != nil {
|
||||
t.Fatal(err)
|
||||
}
|
||||
|
||||
if exp := 4; mapCount != exp {
|
||||
t.Errorf("expected Map to be called %d times; got %d", exp, mapCount)
|
||||
}
|
||||
})
|
||||
|
||||
t.Run("map of kernel sections fials", func(t *testing.T) {
|
||||
defer func() { visitElfSectionsFn = multiboot.VisitElfSections }()
|
||||
expErr := &kernel.Error{Module: "test", Message: "map failed"}
|
||||
|
||||
SetFrameAllocator(func() (pmm.Frame, *kernel.Error) {
|
||||
addr := uintptr(unsafe.Pointer(&reservedPage[0]))
|
||||
return pmm.Frame(addr >> mem.PageShift), nil
|
||||
})
|
||||
activePDTFn = func() uintptr {
|
||||
return uintptr(unsafe.Pointer(&reservedPage[0]))
|
||||
}
|
||||
switchPDTFn = func(_ uintptr) {}
|
||||
translateFn = func(_ uintptr) (uintptr, *kernel.Error) { return 0xbadf00d000, nil }
|
||||
mapTemporaryFn = func(f pmm.Frame) (Page, *kernel.Error) { return Page(f), nil }
|
||||
visitElfSectionsFn = func(v multiboot.ElfSectionVisitor) {
|
||||
v(".text", multiboot.ElfSectionExecutable, 0xbadc0ffee, uint64(mem.PageSize>>1))
|
||||
}
|
||||
mapFn = func(page Page, frame pmm.Frame, flags PageTableEntryFlag) *kernel.Error {
|
||||
return expErr
|
||||
}
|
||||
|
||||
if err := setupPDTForKernel(0); err != expErr {
|
||||
t.Fatalf("expected error: %v; got %v", expErr, err)
|
||||
}
|
||||
})
|
||||
|
||||
t.Run("copy allocator reservations to PDT", func(t *testing.T) {
|
||||
earlyReserveLastUsed = tempMappingAddr - uintptr(mem.PageSize)
|
||||
SetFrameAllocator(func() (pmm.Frame, *kernel.Error) {
|
||||
addr := uintptr(unsafe.Pointer(&reservedPage[0]))
|
||||
return pmm.Frame(addr >> mem.PageShift), nil
|
||||
})
|
||||
activePDTFn = func() uintptr {
|
||||
return uintptr(unsafe.Pointer(&reservedPage[0]))
|
||||
}
|
||||
switchPDTFn = func(_ uintptr) {}
|
||||
translateFn = func(_ uintptr) (uintptr, *kernel.Error) { return 0xbadf00d000, nil }
|
||||
unmapFn = func(p Page) *kernel.Error { return nil }
|
||||
mapTemporaryFn = func(f pmm.Frame) (Page, *kernel.Error) { return Page(f), nil }
|
||||
mapFn = func(page Page, frame pmm.Frame, flags PageTableEntryFlag) *kernel.Error {
|
||||
if exp := PageFromAddress(earlyReserveLastUsed); page != exp {
|
||||
t.Errorf("expected Map to be called with page %d; got %d", exp, page)
|
||||
}
|
||||
|
||||
if exp := pmm.Frame(0xbadf00d000 >> mem.PageShift); frame != exp {
|
||||
t.Errorf("expected Map to be called with frame %d; got %d", exp, frame)
|
||||
}
|
||||
|
||||
if flags&(FlagPresent|FlagRW) != (FlagPresent | FlagRW) {
|
||||
t.Error("expected Map to be called FlagPresent | FlagRW")
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
if err := setupPDTForKernel(0); err != nil {
|
||||
t.Fatal(err)
|
||||
}
|
||||
})
|
||||
|
||||
t.Run("pdt init fails", func(t *testing.T) {
|
||||
expErr := &kernel.Error{Module: "test", Message: "translate failed"}
|
||||
|
||||
SetFrameAllocator(func() (pmm.Frame, *kernel.Error) {
|
||||
addr := uintptr(unsafe.Pointer(&reservedPage[0]))
|
||||
return pmm.Frame(addr >> mem.PageShift), nil
|
||||
})
|
||||
activePDTFn = func() uintptr { return 0 }
|
||||
mapTemporaryFn = func(f pmm.Frame) (Page, *kernel.Error) { return 0, expErr }
|
||||
|
||||
if err := setupPDTForKernel(0); err != expErr {
|
||||
t.Fatalf("expected error: %v; got %v", expErr, err)
|
||||
}
|
||||
})
|
||||
|
||||
t.Run("translation fails for page in reserved address space", func(t *testing.T) {
|
||||
expErr := &kernel.Error{Module: "test", Message: "translate failed"}
|
||||
|
||||
earlyReserveLastUsed = tempMappingAddr - uintptr(mem.PageSize)
|
||||
SetFrameAllocator(func() (pmm.Frame, *kernel.Error) {
|
||||
addr := uintptr(unsafe.Pointer(&reservedPage[0]))
|
||||
return pmm.Frame(addr >> mem.PageShift), nil
|
||||
})
|
||||
activePDTFn = func() uintptr {
|
||||
return uintptr(unsafe.Pointer(&reservedPage[0]))
|
||||
}
|
||||
translateFn = func(_ uintptr) (uintptr, *kernel.Error) {
|
||||
return 0, expErr
|
||||
}
|
||||
|
||||
if err := setupPDTForKernel(0); err != expErr {
|
||||
t.Fatalf("expected error: %v; got %v", expErr, err)
|
||||
}
|
||||
})
|
||||
|
||||
t.Run("map fails for page in reserved address space", func(t *testing.T) {
|
||||
expErr := &kernel.Error{Module: "test", Message: "map failed"}
|
||||
|
||||
earlyReserveLastUsed = tempMappingAddr - uintptr(mem.PageSize)
|
||||
SetFrameAllocator(func() (pmm.Frame, *kernel.Error) {
|
||||
addr := uintptr(unsafe.Pointer(&reservedPage[0]))
|
||||
return pmm.Frame(addr >> mem.PageShift), nil
|
||||
})
|
||||
activePDTFn = func() uintptr {
|
||||
return uintptr(unsafe.Pointer(&reservedPage[0]))
|
||||
}
|
||||
translateFn = func(_ uintptr) (uintptr, *kernel.Error) { return 0xbadf00d000, nil }
|
||||
mapTemporaryFn = func(f pmm.Frame) (Page, *kernel.Error) { return Page(f), nil }
|
||||
mapFn = func(page Page, frame pmm.Frame, flags PageTableEntryFlag) *kernel.Error { return expErr }
|
||||
|
||||
if err := setupPDTForKernel(0); err != expErr {
|
||||
t.Fatalf("expected error: %v; got %v", expErr, err)
|
||||
}
|
||||
})
|
||||
}
|
||||
|
||||
var (
|
||||
emptyInfoData = []byte{
|
||||
0, 0, 0, 0, // size
|
||||
0, 0, 0, 0, // reserved
|
||||
0, 0, 0, 0, // tag with type zero and length zero
|
||||
0, 0, 0, 0,
|
||||
}
|
||||
)
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user