Use PageTable interface in OS

Cargo.toml

@@ -36,6 +36,7 @@ uart_16550 = "0.1"
 lazy_static = { version = "1.0.0", features = ["spin_no_std"] }
 simple-filesystem = { git = "https://github.com/wangrunji0408/SimpleFileSystem-Rust" }
 bit-allocator = { path = "crate/bit-allocator" }
+ucore-memory = { path = "crate/memory" }
 
 [build-dependencies]
 cc = "1.0"

crate/memory/Cargo.toml

@@ -1,5 +1,5 @@
 [package]
-name = "memory"
+name = "ucore-memory"
 version = "0.1.0"
 authors = ["WangRunji <wangrunji0408@163.com>"]
 

crate/memory/src/cow.rs

@@ -22,6 +22,7 @@ impl<T: PageTable> CowExt<T> {
         let entry = self.page_table.map(addr, target);
         entry.set_writable(false);
         entry.set_shared(writable);
+        entry.update();
         let frame = target / PAGE_SIZE;
         match writable {
             true => self.rc_map.write_increase(&frame),
@@ -52,6 +53,7 @@ impl<T: PageTable> CowExt<T> {
             if self.rc_map.read_count(&frame) == 0 && self.rc_map.write_count(&frame) == 1 {
                 entry.clear_shared();
                 entry.set_writable(true);
+                entry.update();
                 self.rc_map.write_decrease(&frame);
                 return true;
             }

crate/memory/src/paging/mock_page_table.rs

@@ -22,6 +22,7 @@ pub struct MockEntry {
 }
 
 impl Entry for MockEntry {
+    fn update(&mut self) {}
     fn accessed(&self) -> bool { self.accessed }
     fn dirty(&self) -> bool { self.dirty }
     fn writable(&self) -> bool { self.writable }
@@ -42,6 +43,11 @@ impl Entry for MockEntry {
         self.writable_shared = false;
         self.readonly_shared = false;
     }
+
+    fn user(&self) -> bool { unimplemented!() }
+    fn set_user(&mut self, value: bool) { unimplemented!() }
+    fn execute(&self) -> bool { unimplemented!() }
+    fn set_execute(&mut self, value: bool) { unimplemented!() }
 }
 
 type PageFaultHandler = Box<FnMut(&mut MockPageTable, VirtAddr)>;
@@ -49,7 +55,6 @@ type PageFaultHandler = Box<FnMut(&mut MockPageTable, VirtAddr)>;
 impl PageTable for MockPageTable {
     type Entry = MockEntry;
 
-    /// Map a page, return false if no more space
     fn map(&mut self, addr: VirtAddr, target: PhysAddr) -> &mut Self::Entry {
         let entry = &mut self.entries[addr / PAGE_SIZE];
         assert!(!entry.present);

crate/memory/src/paging/mod.rs

@@ -1,6 +1,12 @@
+//! Generic page table interface
+//!
+//! Implemented for every architecture, used by OS.
+
 use super::*;
+#[cfg(test)]
 pub use self::mock_page_table::MockPageTable;
 
+#[cfg(test)]
 mod mock_page_table;
 
 pub trait PageTable {
@@ -13,6 +19,11 @@ pub trait PageTable {
 }
 
 pub trait Entry {
+    /// IMPORTANT!
+    /// This must be called after any change to ensure it become effective.
+    /// Usually this will make a flush to TLB/MMU.
+    fn update(&mut self);
+
     /// Will be set when accessed
     fn accessed(&self) -> bool;
     /// Will be set when written
@@ -34,4 +45,9 @@ pub trait Entry {
     fn readonly_shared(&self) -> bool;
     fn set_shared(&mut self, writable: bool);
     fn clear_shared(&mut self);
+
+    fn user(&self) -> bool;
+    fn set_user(&mut self, value: bool);
+    fn execute(&self) -> bool;
+    fn set_execute(&mut self, value: bool);
 }

src/arch/x86_64/paging/mod.rs

@@ -1,20 +1,11 @@
 use memory::*;
-//pub use self::cow::*;
-use x86_64::structures::paging::*;
-use x86_64::registers::control::{Cr3, Cr3Flags};
+pub use ucore_memory::paging::{Entry, PageTable};
 use x86_64::instructions::tlb;
+use x86_64::registers::control::{Cr3, Cr3Flags};
+use x86_64::structures::paging::{Mapper, PageTable as x86PageTable, PageTableEntry, PageTableFlags as EF, RecursivePageTable};
+pub use x86_64::structures::paging::{FrameAllocator, FrameDeallocator, Page, PageRange, PhysFrame as Frame, Size4KiB};
 use x86_64::ux::u9;
 
-pub type Frame = PhysFrame;
-pub type EntryFlags = PageTableFlags;
-pub type ActivePageTable = RecursivePageTable<'static>;
-
-pub use x86_64::structures::paging::{Page, PageRange, Mapper, FrameAllocator, FrameDeallocator, Size4KiB, PageTable};
-
-//mod cow;
-
-const ENTRY_COUNT: usize = 512;
-
 pub trait PageExt {
     fn of_addr(address: VirtAddr) -> Self;
     fn range_of(begin: VirtAddr, end: VirtAddr) -> PageRange;
@@ -40,18 +31,53 @@ impl FrameExt for Frame {
     }
 }
 
-pub trait ActiveTableExt {
-    fn with(&mut self, table: &mut InactivePageTable, f: impl FnOnce(&mut ActivePageTable));
-    fn map_to_(&mut self, page: Page, frame: Frame, flags: EntryFlags);
+pub struct ActivePageTable(RecursivePageTable<'static>);
+
+pub struct PageEntry(PageTableEntry);
+
+impl PageTable for ActivePageTable {
+    type Entry = PageEntry;
+
+    fn map(&mut self, addr: usize, target: usize) -> &mut PageEntry {
+        let flags = EF::PRESENT | EF::WRITABLE | EF::NO_EXECUTE;
+        self.0.map_to(Page::of_addr(addr), Frame::of_addr(target), flags, &mut frame_allocator())
+            .unwrap().flush();
+        self.get_entry(addr)
+    }
+
+    fn unmap(&mut self, addr: usize) {
+        let (frame, flush) = self.0.unmap(Page::of_addr(addr)).unwrap();
+        flush.flush();
+    }
+
+    fn get_entry(&mut self, addr: usize) -> &mut PageEntry {
+        let entry_addr = ((addr >> 9) & 0o777_777_777_7770) | 0xffffff80_00000000;
+        unsafe { &mut *(entry_addr as *mut PageEntry) }
+    }
+
+    fn read_page(&mut self, addr: usize, data: &mut [u8]) {
+        use core::slice;
+        let mem = unsafe { slice::from_raw_parts((addr & !0xfffusize) as *const u8, 4096) };
+        data.copy_from_slice(mem);
+    }
+
+    fn write_page(&mut self, addr: usize, data: &[u8]) {
+        use core::slice;
+        let mem = unsafe { slice::from_raw_parts_mut((addr & !0xfffusize) as *mut u8, 4096) };
+        mem.copy_from_slice(data);
+    }
 }
 
-impl ActiveTableExt for ActivePageTable {
-    fn with(&mut self, table: &mut InactivePageTable, f: impl FnOnce(&mut ActivePageTable)) {
-        with_temporary_map(self, &Cr3::read().0, |active_table, p4_table: &mut PageTable| {
+impl ActivePageTable {
+    pub unsafe fn new() -> Self {
+        ActivePageTable(RecursivePageTable::new(&mut *(0xffffffff_fffff000 as *mut _)).unwrap())
+    }
+    pub fn with(&mut self, table: &mut InactivePageTable, f: impl FnOnce(&mut ActivePageTable)) {
+        with_temporary_map(self, &Cr3::read().0, |active_table, p4_table: &mut x86PageTable| {
             let backup = p4_table[0o777].clone();
 
             // overwrite recursive mapping
-            p4_table[0o777].set_frame(table.p4_frame.clone(), EntryFlags::PRESENT | EntryFlags::WRITABLE);
+            p4_table[0o777].set_frame(table.p4_frame.clone(), EF::PRESENT | EF::WRITABLE);
             tlb::flush_all();
 
             // execute f in the new context
@@ -62,20 +88,55 @@ impl ActiveTableExt for ActivePageTable {
             tlb::flush_all();
         });
     }
-    fn map_to_(&mut self, page: Page<Size4KiB>, frame: PhysFrame<Size4KiB>, flags: EntryFlags) {
-        self.map_to(page, frame, flags, &mut frame_allocator()).unwrap().flush();
+    pub fn map_to(&mut self, page: Page, frame: Frame) -> &mut PageEntry {
+        self.map(page.start_address().as_u64() as usize, frame.start_address().as_u64() as usize)
+    }
+}
 
-        // Set user bit for p1-p4 entry
-        // It's a workaround since x86_64 PageTable do not set user bit.
-        if flags.contains(EntryFlags::USER_ACCESSIBLE) {
-            let mut addr = page.start_address().as_u64();
-            for _ in 0..4 {
+impl Entry for PageEntry {
+    fn update(&mut self) {
+        use x86_64::{VirtAddr, instructions::tlb::flush};
+        let addr = VirtAddr::new_unchecked((self as *const _ as u64) << 9);
+        flush(addr);
+    }
+    fn accessed(&self) -> bool { self.0.flags().contains(EF::ACCESSED) }
+    fn dirty(&self) -> bool { self.0.flags().contains(EF::DIRTY) }
+    fn writable(&self) -> bool { self.0.flags().contains(EF::WRITABLE) }
+    fn present(&self) -> bool { self.0.flags().contains(EF::PRESENT) }
+    fn clear_accessed(&mut self) { self.as_flags().remove(EF::ACCESSED); }
+    fn clear_dirty(&mut self) { self.as_flags().remove(EF::DIRTY); }
+    fn set_writable(&mut self, value: bool) { self.as_flags().set(EF::WRITABLE, value); }
+    fn set_present(&mut self, value: bool) { self.as_flags().set(EF::PRESENT, value); }
+    fn target(&self) -> usize { self.0.addr().as_u64() as usize }
+    fn writable_shared(&self) -> bool { self.0.flags().contains(EF::BIT_10) }
+    fn readonly_shared(&self) -> bool { self.0.flags().contains(EF::BIT_9) }
+    fn set_shared(&mut self, writable: bool) {
+        let flags = self.as_flags();
+        flags.set(EF::BIT_10, writable);
+        flags.set(EF::BIT_9, !writable);
+    }
+    fn clear_shared(&mut self) { self.as_flags().remove(EF::BIT_9 | EF::BIT_10); }
+    fn user(&self) -> bool { self.0.flags().contains(EF::USER_ACCESSIBLE) }
+    fn set_user(&mut self, value: bool) {
+        self.as_flags().set(EF::USER_ACCESSIBLE, value);
+        if value {
+            let mut addr = self as *const _ as usize;
+            for _ in 0..3 {
+                // Upper level entry
                 addr = ((addr >> 9) & 0o777_777_777_7770) | 0xffffff80_00000000;
                 // set USER_ACCESSIBLE
-                unsafe { (*(addr as *mut EntryFlags)).insert(EntryFlags::USER_ACCESSIBLE) };
+                unsafe { (*(addr as *mut EF)).insert(EF::USER_ACCESSIBLE) };
             }
         }
     }
+    fn execute(&self) -> bool { !self.0.flags().contains(EF::NO_EXECUTE) }
+    fn set_execute(&mut self, value: bool) { self.as_flags().set(EF::NO_EXECUTE, !value); }
+}
+
+impl PageEntry {
+    fn as_flags(&mut self) -> &mut EF {
+        unsafe { &mut *(self as *mut _ as *mut EF) }
+    }
 }
 
 #[derive(Debug)]
@@ -85,13 +146,23 @@ pub struct InactivePageTable {
 
 impl InactivePageTable {
     pub fn new(frame: Frame, active_table: &mut ActivePageTable) -> InactivePageTable {
-        with_temporary_map(active_table, &frame, |_, table: &mut PageTable| {
+        with_temporary_map(active_table, &frame, |_, table: &mut x86PageTable| {
             table.zero();
             // set up recursive mapping for the table
-            table[511].set_frame(frame.clone(), EntryFlags::PRESENT | EntryFlags::WRITABLE);
+            table[511].set_frame(frame.clone(), EF::PRESENT | EF::WRITABLE);
         });
         InactivePageTable { p4_frame: frame }
     }
+    pub fn map_kernel(&mut self, active_table: &mut ActivePageTable) {
+        let mut table = unsafe { &mut *(0xffffffff_fffff000 as *mut x86PageTable) };
+        let e510 = table[510].clone();
+        let e509 = table[509].clone();
+
+        active_table.with(self, |pt: &mut ActivePageTable| {
+            table[510] = e510;
+            table[509] = e509;
+        });
+    }
     pub fn switch(&self) {
         let old_frame = Cr3::read().0;
         let new_frame = self.p4_frame.clone();
@@ -112,15 +183,15 @@ impl Drop for InactivePageTable {
     }
 }
 
-fn with_temporary_map(active_table: &mut ActivePageTable, frame: &Frame, f: impl FnOnce(&mut ActivePageTable, &mut PageTable)) {
+fn with_temporary_map(active_table: &mut ActivePageTable, frame: &Frame, f: impl FnOnce(&mut ActivePageTable, &mut x86PageTable)) {
     // Create a temporary page
     let page = Page::of_addr(0xcafebabe);
-    assert!(active_table.translate_page(page).is_none(), "temporary page is already mapped");
+    assert!(active_table.0.translate_page(page).is_none(), "temporary page is already mapped");
     // Map it to table
-    active_table.map_to_(page, frame.clone(), EntryFlags::PRESENT | EntryFlags::WRITABLE);
+    active_table.map_to(page, frame.clone());
     // Call f
     let table = unsafe { &mut *page.start_address().as_mut_ptr() };
     f(active_table, table);
     // Unmap the page
-    active_table.unmap(page).unwrap().1.flush();
+    active_table.unmap(0xcafebabe);
 }

src/lib.rs

@@ -36,6 +36,7 @@ extern crate simple_filesystem;
 extern crate spin;
 extern crate syscall as redox_syscall;
 extern crate uart_16550;
+extern crate ucore_memory;
 extern crate volatile;
 #[macro_use]
 extern crate x86_64;

src/memory/memory_set.rs

@@ -67,54 +67,61 @@ impl MemoryArea {
             Some(phys_start) => {
                 for page in Page::range_of(self.start_addr, self.end_addr) {
                     let frame = Frame::of_addr(phys_start.get() + page.start_address().as_u64() as usize - self.start_addr);
-                    pt.map_to_(page, frame, self.flags.0);
+                    self.flags.apply(pt.map_to(page, frame));
                 }
             }
             None => {
                 for page in Page::range_of(self.start_addr, self.end_addr) {
                     let frame = alloc_frame();
-                    pt.map_to_(page, frame, self.flags.0);
+                    self.flags.apply(pt.map_to(page, frame));
                 }
             }
         }
     }
     fn unmap(&self, pt: &mut ActivePageTable) {
         for page in Page::range_of(self.start_addr, self.end_addr) {
-            let (frame, flush) = pt.unmap(page).unwrap();
-            flush.flush();
+            let addr = page.start_address().as_u64() as usize;
             if self.phys_start_addr.is_none() {
+                let frame = Frame::of_addr(pt.get_entry(addr).target());
                 dealloc_frame(frame);
             }
+            pt.unmap(addr);
         }
     }
 }
 
-#[derive(Debug, Copy, Clone, Eq, PartialEq)]
-pub struct MemoryAttr(EntryFlags);
-
-impl Default for MemoryAttr {
-    fn default() -> Self {
-        MemoryAttr(EntryFlags::PRESENT | EntryFlags::NO_EXECUTE | EntryFlags::WRITABLE)
-    }
+#[derive(Debug, Copy, Clone, Eq, PartialEq, Default)]
+pub struct MemoryAttr {
+    user: bool,
+    readonly: bool,
+    execute: bool,
+    hide: bool,
 }
 
 impl MemoryAttr {
     pub fn user(mut self) -> Self {
-        self.0 |= EntryFlags::USER_ACCESSIBLE;
+        self.user = true;
         self
     }
     pub fn readonly(mut self) -> Self {
-        self.0.remove(EntryFlags::WRITABLE);
+        self.readonly = true;
         self
     }
     pub fn execute(mut self) -> Self {
-        self.0.remove(EntryFlags::NO_EXECUTE);
+        self.execute = true;
         self
     }
     pub fn hide(mut self) -> Self {
-        self.0.remove(EntryFlags::PRESENT);
+        self.hide = true;
         self
     }
+    fn apply(&self, entry: &mut impl Entry) {
+        if self.user { entry.set_user(true); }
+        if self.readonly { entry.set_writable(false); }
+        if self.execute { entry.set_execute(true); }
+        if self.hide { entry.set_present(false); }
+        if self.user || self.readonly || self.execute || self.hide { entry.update(); }
+    }
 }
 
 /// 内存空间集合，包含若干段连续空间
@@ -226,15 +233,6 @@ fn new_page_table_with_kernel() -> InactivePageTable {
     let frame = alloc_frame();
     let mut active_table = active_table();
     let mut page_table = InactivePageTable::new(frame, &mut active_table);
-
-    use consts::{KERNEL_HEAP_PML4, KERNEL_PML4};
-    let mut table = unsafe { &mut *(0xffffffff_fffff000 as *mut PageTable) };
-    let e510 = table[KERNEL_PML4].clone();
-    let e509 = table[KERNEL_HEAP_PML4].clone();
-
-    active_table.with(&mut page_table, |pt: &mut ActivePageTable| {
-        table[KERNEL_PML4] = e510;
-        table[KERNEL_HEAP_PML4] = e509;
-    });
+    page_table.map_kernel(&mut active_table);
     page_table
 }

src/memory/mod.rs

@@ -8,6 +8,7 @@ pub use self::memory_set::*;
 pub use self::stack_allocator::*;
 use spin::{Mutex, MutexGuard};
 use super::HEAP_ALLOCATOR;
+use ucore_memory::paging::PageTable;
 
 mod memory_set;
 mod stack_allocator;
@@ -42,7 +43,7 @@ fn alloc_stack(size_in_pages: usize) -> Stack {
 fn active_table() -> MutexGuard<'static, ActivePageTable> {
     lazy_static! {
         static ref ACTIVE_TABLE: Mutex<ActivePageTable> = Mutex::new(unsafe {
-            ActivePageTable::new(&mut *(0xffffffff_fffff000 as *mut _)).unwrap()
+            ActivePageTable::new()
         });
     }
     ACTIVE_TABLE.lock()
@@ -153,11 +154,10 @@ fn get_init_kstack_and_set_guard_page() -> Stack {
 
     extern { fn stack_bottom(); }
     let stack_bottom = PhysAddr::new(stack_bottom as u64).to_kernel_virtual();
-    let stack_bottom_page = Page::of_addr(stack_bottom);
 
     // turn the stack bottom into a guard page
-    active_table().unmap(stack_bottom_page);
-    debug!("guard page at {:?}", stack_bottom_page.start_address());
+    active_table().unmap(stack_bottom);
+    debug!("guard page at {:?}", stack_bottom);
 
     Stack::new(stack_bottom + 8 * PAGE_SIZE, stack_bottom + 1 * PAGE_SIZE)
 }

src/memory/stack_allocator.rs

@@ -1,5 +1,5 @@
-use super::*;
 use memory::PAGE_SIZE;
+use super::*;
 
 // TODO: use BitAllocator & alloc fixed size stack
 pub struct StackAllocator {
@@ -41,7 +41,7 @@ impl StackAllocator {
                 // map stack pages to physical frames
                 for page in Page::range_inclusive(start, end) {
                     let frame = alloc_frame();
-                    active_table.map_to_(page, frame, EntryFlags::PRESENT | EntryFlags::WRITABLE);
+                    active_table.map_to(page, frame);
                 }
 
                 // create a new stack