sync page cache after mmap (#39)

e1000/e1000.go

@@ -139,7 +139,7 @@ func (d *driver) Init(dev *pci.Device) error {
 	if !ismem {
 		panic("not memory bar")
 	}
-	mm.Fixmap(uintptr(baddr), uintptr(baddr), uintptr(blen))
+	mm.SysFixedMmap(uintptr(baddr), uintptr(blen))
 	d.bar = uintptr(baddr)
 	debug.Logf("[e1000] mmap for bar0 0x%x", d.bar)
 

kernel/postinit.go

@@ -5,6 +5,7 @@ import "github.com/icexin/eggos/clock"
 // called when go runtime init done
 func Init() {
 	initClockTime()
+	idle_init()
 	go traploop()
 	go handleForward()
 	bootstrapDone = true

kernel/syscall.go

@@ -44,6 +44,7 @@ const (
 
 	SYS_WAIT_IRQ     = 500
 	SYS_WAIT_SYSCALL = 501
+	SYS_FIXED_MMAP   = 502
 )
 
 const (
@@ -70,9 +71,9 @@ var (
 		SYS_EXIT, SYS_set_thread_area, SYS_sched_yield, SYS_nanosleep, SYS_brk,
 		SYS_munmap, SYS_mmap2, SYS_madvise, SYS_clone, SYS_gettid,
 		SYS_futex, SYS_rt_sigaction, SYS_rt_sigprocmask, SYS_sigaltstack,
-		SYS_clock_gettime, SYS_exit_group, SYS_WAIT_IRQ, SYS_WAIT_SYSCALL,
+		SYS_clock_gettime, SYS_exit_group,
 		syscall.SYS_EPOLL_CREATE1, syscall.SYS_EPOLL_CTL, syscall.SYS_EPOLL_WAIT,
-		// SYS_RANDOM,
+		SYS_WAIT_IRQ, SYS_WAIT_SYSCALL, SYS_FIXED_MMAP,
 	}
 
 	syscalltask threadptr
@@ -253,6 +254,8 @@ func doBootSyscall(no, a0, a1, a2, a3, a4, a5 uintptr) uintptr {
 		return waitIRQ()
 	case SYS_WAIT_SYSCALL:
 		return fetchPendingCall()
+	case SYS_FIXED_MMAP:
+		return fixedmmap(a0, a1)
 
 	default:
 		uart.WriteString("unknown syscall\n")
@@ -265,14 +268,20 @@ func doBootSyscall(no, a0, a1, a2, a3, a4, a5 uintptr) uintptr {
 //go:nosplit
 func mmap(addr unsafe.Pointer, n uintptr, prot, flags, fd int32, off uint32) uintptr {
 	// called on sysReserve
-	if prot == _PROT_NONE {
+	if prot == syscall.PROT_NONE {
 		return mm.Sbrk(n)
 	}
 
 	// called on sysMap and sysAlloc
 	return mm.Mmap(uintptr(addr), n)
 }
 
+//go:nopslit
+func fixedmmap(addr uintptr, size uintptr) uintptr {
+	mm.Fixmap(addr, addr, size)
+	return addr
+}
+
 //go:nosplit
 func syscal_init() {
 	epollInit()

kernel/thread.go

@@ -201,18 +201,21 @@ func sys_hlt()
 // thread0 is the first thread
 //go:nosplit
 func thread0() {
+	// jump to go rt0
+	go_entry()
+	panic("main return")
+}
+
+// run when after main init
+func idle_init() {
 	// thread0 clone idle thread
-	stack := mm.Mmap(0, _THREAD_STACK_SIZE) + _THREAD_STACK_SIZE
+	stack := mm.SysMmap(0, _THREAD_STACK_SIZE) + _THREAD_STACK_SIZE
 	tid := sys_clone(sys.FuncPC(idle), stack)
 	idle_thread = (threadptr)(unsafe.Pointer(&threads[tid]))
 
 	// make idle thread running at ring0, so that it can call HLT instruction.
 	tf := idle_thread.ptr().tf
 	tf.CS = _KCODE_IDX << 3
-
-	// jump to go rt0
-	go_entry()
-	panic("main return")
 }
 
 //go:nosplit

mm/mm.go

@@ -194,12 +194,16 @@ func Mmap(va, size uintptr) uintptr {
 		va = kmm.sbrk(size)
 	}
 	vmm.mmap(va, size, PTE_P|PTE_W|PTE_U)
+	// flush page table cache
+	lcr3(vmm.pgdir)
 	return va
 }
 
 //go:nosplit
 func Fixmap(va, pa, size uintptr) {
 	vmm.fixmap(va, pa, size, PTE_P|PTE_W|PTE_U)
+	// flush page table cache
+	lcr3(vmm.pgdir)
 }
 
 //go:nosplit

mm/sys.go

@@ -0,0 +1,29 @@
+package mm
+
+import (
+	"syscall"
+)
+
+const (
+	// sync with kernel
+	_SYS_FIXED_MMAP = 502
+)
+
+// SysMmap like Mmap but can run in user mode
+// wraper of syscall.Mmap
+func SysMmap(vaddr, size uintptr) uintptr {
+	mem, _, err := syscall.Syscall6(syscall.SYS_MMAP2, uintptr(vaddr), size, syscall.PROT_READ|syscall.PROT_WRITE, 0, 0, 0)
+	if err != 0 {
+		panic(err.Error())
+	}
+	return mem
+}
+
+// SysFixedMmap map the same physical address to the virtual address
+// run in user mode
+func SysFixedMmap(addr, size uintptr) {
+	_, _, err := syscall.Syscall(_SYS_FIXED_MMAP, addr, size, 0)
+	if err != 0 {
+		panic(err.Error())
+	}
+}

vbe/fb.go

@@ -74,7 +74,7 @@ func Init() {
 		Pitch:  bootInfo.FramebufferPitch,
 	}
 
-	mm.Fixmap(uintptr(info.Addr), uintptr(info.Addr), uintptr(info.Width*info.Height*4))
+	mm.SysFixedMmap(uintptr(info.Addr), uintptr(info.Width*info.Height*4))
 	fbbuf = (*[10 << 20]uint8)(unsafe.Pointer(uintptr(info.Addr)))[:info.Width*info.Height*4]
 	buffer = make([]uint8, len(fbbuf))
 	DefaultView = NewView()