Refactor `remap_the_kernel` using `MemorySet`

src/arch/x86_64/paging/entry.rs

@@ -1,5 +1,4 @@
 use memory::Frame;
-use multiboot2::ElfSection;
 
 pub struct Entry(u64);
 
@@ -47,29 +46,6 @@ bitflags! {
     }
 }
 
-
-impl EntryFlags {
-    pub fn from_elf_section_flags(section: &ElfSection) -> EntryFlags {
-        use multiboot2::{ELF_SECTION_ALLOCATED, ELF_SECTION_WRITABLE,
-            ELF_SECTION_EXECUTABLE};
-
-        let mut flags = EntryFlags::empty();
-
-        if section.flags().contains(ELF_SECTION_ALLOCATED) {
-            // section is loaded to memory
-            flags = flags | EntryFlags::PRESENT;
-        }
-        if section.flags().contains(ELF_SECTION_WRITABLE) {
-            flags = flags | EntryFlags::WRITABLE;
-        }
-        if !section.flags().contains(ELF_SECTION_EXECUTABLE) {
-            flags = flags | EntryFlags::NO_EXECUTE;
-        }
-
-        flags
-    }
-}
-
 use core::fmt;
 use core::fmt::Debug;
 

src/arch/x86_64/paging/mod.rs

@@ -47,6 +47,14 @@ impl Page {
             end,
         }
     }
+
+    /// Iterate pages of address [begin, end)
+    pub fn range_of(begin: VirtAddr, end: VirtAddr) -> PageIter {
+        PageIter {
+            start: Page::of_addr(begin),
+            end: Page::of_addr(end - 1),
+        }
+    }
 }
 
 impl Add<usize> for Page {

src/memory/memory_set.rs

@@ -1,5 +1,6 @@
 use alloc::vec::Vec;
 use super::*;
+use core::fmt::{Debug, Formatter, Error};
 
 /// 一片连续内存空间，有相同的访问权限
 /// 对应ucore中 `vma_struct`
@@ -7,6 +8,7 @@ use super::*;
 pub struct MemoryArea {
     pub start_addr: VirtAddr,
     pub end_addr: VirtAddr,
+    pub phys_start_addr: Option<PhysAddr>,
     pub flags: u32,
     pub name: &'static str,
     pub mapped: bool,
@@ -25,14 +27,23 @@ impl MemoryArea {
 /// 对应ucore中 `mm_struct`
 pub struct MemorySet {
     areas: Vec<MemoryArea>,
-    page_table: InactivePageTable,
+    pub(in memory) page_table: Option<InactivePageTable>,
 }
 
 impl MemorySet {
-    pub fn new(mc: &mut MemoryController) -> Self {
+    pub fn new() -> Self {
         MemorySet {
             areas: Vec::<MemoryArea>::new(),
-            page_table: mc.new_page_table(),
+            page_table: None,
+        }
+    }
+    /// Used for remap_kernel() where heap alloc is unavailable
+    pub unsafe fn new_from_raw_space(slice: &mut [u8]) -> Self {
+        use core::mem::size_of;
+        let cap = slice.len() / size_of::<MemoryArea>();
+        MemorySet {
+            areas: Vec::<MemoryArea>::from_raw_parts(slice.as_ptr() as *mut MemoryArea, 0, cap),
+            page_table: None,
         }
     }
     pub fn find_area(&self, addr: VirtAddr) -> Option<&MemoryArea> {
@@ -47,8 +58,38 @@ impl MemorySet {
         }
         self.areas.push(area);
     }
-    pub fn map(&mut self, mc: &mut MemoryController) {
-//        mc.active_table.with(self.page_table, )
+    pub fn map(&mut self, active_table: &mut ActivePageTable) {
+        let mut page_table = InactivePageTable::new(alloc_frame(), active_table);
+        active_table.with(&mut page_table, |pt: &mut Mapper| {
+            for area in self.areas.iter_mut() {
+                if area.mapped {
+                    continue
+                }
+                match area.phys_start_addr {
+                    Some(phys_start) => {
+                        for page in Page::range_of(area.start_addr, area.end_addr) {
+                            let frame = Frame::of_addr(phys_start.get() + page.start_address() - area.start_addr);
+                            pt.map_to(page, frame.clone(), EntryFlags::from_bits(area.flags.into()).unwrap());
+                        }
+                    },
+                    None => {
+                        for page in Page::range_of(area.start_addr, area.end_addr) {
+                            pt.map(page, EntryFlags::from_bits(area.flags.into()).unwrap());
+                        }
+                    },
+                }
+                area.mapped = true;
+            }
+        });
+        self.page_table = Some(page_table);
+    }
+}
+
+impl Debug for MemorySet {
+    fn fmt(&self, f: &mut Formatter) -> Result<(), Error> {
+        f.debug_list()
+            .entries(self.areas.iter())
+            .finish()
     }
 }
 

src/memory/mod.rs

@@ -42,17 +42,6 @@ pub fn init(boot_info: &BootInformation) -> MemoryController {
     let boot_info_start = PhysAddr(boot_info.start_address() as u64);
     let boot_info_end = PhysAddr(boot_info.end_address() as u64);
 
-    println!("kernel start: {:#x}, kernel end: {:#x}",
-             kernel_start,
-             kernel_end);
-    println!("multiboot start: {:#x}, multiboot end: {:#x}",
-             boot_info_start,
-             boot_info_end);
-    println!("memory area:");
-    for area in memory_map_tag.memory_areas() {
-        println!("  addr: {:#x}, size: {:#x}", area.base_addr, area.length);
-    }
-
     *FRAME_ALLOCATOR.lock() = Some(AreaFrameAllocator::new(
         kernel_start, kernel_end,
         boot_info_start, boot_info_end,
@@ -64,18 +53,9 @@ pub fn init(boot_info: &BootInformation) -> MemoryController {
     use self::paging::Page;
     use consts::{KERNEL_HEAP_OFFSET, KERNEL_HEAP_SIZE};
 
-    let heap_start_page = Page::of_addr(KERNEL_HEAP_OFFSET);
-    let heap_end_page = Page::of_addr(KERNEL_HEAP_OFFSET + KERNEL_HEAP_SIZE-1);
-
-    for page in Page::range_inclusive(heap_start_page, heap_end_page) {
-        active_table.map(page, EntryFlags::WRITABLE);
-    }
-
     let stack_allocator = {
-        let stack_alloc_start = heap_end_page + 1;
-        let stack_alloc_end = stack_alloc_start + 100;
-        let stack_alloc_range = Page::range_inclusive(stack_alloc_start,
-                                                      stack_alloc_end);
+        let stack_alloc_range = Page::range_of(KERNEL_HEAP_OFFSET + KERNEL_HEAP_SIZE,
+                                               KERNEL_HEAP_OFFSET + KERNEL_HEAP_SIZE + 0x100000);
         stack_allocator::StackAllocator::new(stack_alloc_range)
     };
     
@@ -89,53 +69,37 @@ pub fn init(boot_info: &BootInformation) -> MemoryController {
 pub fn remap_the_kernel(boot_info: &BootInformation) -> (ActivePageTable, Stack)
 {
     let mut active_table = unsafe { ActivePageTable::new() };
-    let mut new_table =
-        InactivePageTable::new(alloc_frame(), &mut active_table);
-
-    active_table.with(&mut new_table, |mapper| {
-        let elf_sections_tag = boot_info.elf_sections_tag()
-            .expect("Memory map tag required");
-
-        for section in elf_sections_tag.sections() {
-            if !section.is_allocated() {
-                // section is not loaded to memory
-                continue;
-            }
-            assert_eq!(section.start_address() % PAGE_SIZE, 0, "sections need to be page aligned");
-
-            println!("mapping section at addr: {:#x}, size: {:#x}",
-                section.addr, section.size);
+    let mut memory_set = MemorySet::from(boot_info.elf_sections_tag().unwrap());
 
-            let flags = EntryFlags::from_elf_section_flags(section);
-
-            fn to_physical_frame(addr: usize) -> Frame {
-                Frame::of_addr(
-                    if addr < KERNEL_OFFSET { addr } 
-                    else { addr - KERNEL_OFFSET })
-            }
-
-            let start_frame = to_physical_frame(section.start_address());
-            let end_frame = to_physical_frame(section.end_address() - 1);
-
-            for frame in Frame::range_inclusive(start_frame, end_frame) {
-                let page = Page::of_addr(frame.start_address().to_kernel_virtual());
-                mapper.map_to(page, frame, flags);
-            }
-        }
-
-        // identity map the VGA text buffer
-        let vga_buffer_frame = Frame::of_addr(0xb8000);
-        mapper.identity_map(vga_buffer_frame, EntryFlags::WRITABLE);
-
-        // identity map the multiboot info structure
-        let multiboot_start = Frame::of_addr(boot_info.start_address());
-        let multiboot_end = Frame::of_addr(boot_info.end_address() - 1);
-        for frame in Frame::range_inclusive(multiboot_start, multiboot_end) {
-            mapper.identity_map(frame, EntryFlags::PRESENT);
-        }
+    use consts::{KERNEL_HEAP_OFFSET, KERNEL_HEAP_SIZE};
+    memory_set.push(MemoryArea {
+        start_addr: 0xb8000,
+        end_addr: 0xb9000,
+        phys_start_addr: Some(PhysAddr(0xb8000)),
+        flags: EntryFlags::WRITABLE.bits() as u32,
+        name: "VGA",
+        mapped: false,
+    });
+    memory_set.push(MemoryArea {
+        start_addr: boot_info.start_address(),
+        end_addr: boot_info.end_address(),
+        phys_start_addr: Some(PhysAddr(boot_info.start_address() as u64)),
+        flags: EntryFlags::PRESENT.bits() as u32,
+        name: "multiboot",
+        mapped: false,
+    });
+    memory_set.push(MemoryArea {
+        start_addr: KERNEL_HEAP_OFFSET,
+        end_addr: KERNEL_HEAP_OFFSET + KERNEL_HEAP_SIZE,
+        phys_start_addr: None,
+        flags: EntryFlags::WRITABLE.bits() as u32,
+        name: "kernel_heap",
+        mapped: false,
     });
+    memory_set.map(&mut active_table);
+    println!("{:#x?}", memory_set);
 
-    let old_table = active_table.switch(new_table);
+    let old_table = active_table.switch(memory_set.page_table.take().unwrap());
     println!("NEW TABLE!!!");
 
     // turn the stack bottom into a guard page
@@ -149,6 +113,72 @@ pub fn remap_the_kernel(boot_info: &BootInformation) -> (ActivePageTable, Stack)
     (active_table, kernel_stack)
 }
 
+use multiboot2::{ElfSectionsTag, ElfSection, ElfSectionFlags};
+
+impl From<&'static ElfSectionsTag> for MemorySet {
+    fn from(sections: &'static ElfSectionsTag) -> Self {
+        assert_has_not_been_called!();
+        // WARNING: must ensure it's large enough
+        static mut SPACE: [u8; 0x1000] = [0; 0x1000];
+        let mut set = unsafe { MemorySet::new_from_raw_space(&mut SPACE) };
+        for section in sections.sections() {
+            if !section.is_allocated() {
+                // section is not loaded to memory
+                continue;
+            }
+            set.push(MemoryArea::from(section));
+        }
+        set
+    }
+}
+
+impl<'a> From<&'a ElfSection> for MemoryArea {
+    fn from(section: &'a ElfSection) -> Self {
+        use self::address::FromToVirtualAddress;
+        assert_eq!(section.start_address() % PAGE_SIZE, 0, "sections need to be page aligned");
+        if section.start_address() < KERNEL_OFFSET {
+            MemoryArea {
+                start_addr: section.start_address() + KERNEL_OFFSET,
+                end_addr: section.end_address() + KERNEL_OFFSET,
+                phys_start_addr: Some(PhysAddr(section.start_address() as u64)),
+                flags: EntryFlags::from(section.flags()).bits() as u32,
+                name: "",
+                mapped: false,
+            }
+        } else {
+            MemoryArea {
+                start_addr: section.start_address(),
+                end_addr: section.end_address(),
+                phys_start_addr: Some(PhysAddr::from_kernel_virtual(section.start_address())),
+                flags: EntryFlags::from(section.flags()).bits() as u32,
+                name: "",
+                mapped: false,
+            }
+        }
+    }
+}
+
+impl From<ElfSectionFlags> for EntryFlags {
+    fn from(elf_flags: ElfSectionFlags) -> Self {
+        use multiboot2::{ELF_SECTION_ALLOCATED, ELF_SECTION_WRITABLE,
+                         ELF_SECTION_EXECUTABLE};
+
+        let mut flags = EntryFlags::empty();
+
+        if elf_flags.contains(ELF_SECTION_ALLOCATED) {
+            // section is loaded to memory
+            flags = flags | EntryFlags::PRESENT;
+        }
+        if elf_flags.contains(ELF_SECTION_WRITABLE) {
+            flags = flags | EntryFlags::WRITABLE;
+        }
+        if !elf_flags.contains(ELF_SECTION_EXECUTABLE) {
+            flags = flags | EntryFlags::NO_EXECUTE;
+        }
+        flags
+    }
+}
+
 pub struct MemoryController {
     pub kernel_stack: Option<Stack>,
     active_table: paging::ActivePageTable,

src/process/process.rs

@@ -2,13 +2,14 @@ use super::*;
 use memory::Stack;
 use xmas_elf::ElfFile;
 use core::slice;
+use alloc::rc::Rc;
 
 #[derive(Debug)]
 pub struct Process {
     pub(in process) pid: Pid,
                     name: &'static str,
                     kstack: Stack,
-    //    page_table: Box<PageTable>,
+    //                    memory_set: Rc<MemorySet>,
     pub(in process) status: Status,
     pub(in process) rsp: usize,
 }
@@ -53,22 +54,19 @@ impl Process {
     pub fn new_user(begin: usize, end: usize, mc: &mut MemoryController) -> Self {
         let slice = unsafe{ slice::from_raw_parts(begin as *const u8, end - begin) };
         let elf = ElfFile::new(slice).expect("failed to read elf");
-        for program_header in elf.program_iter() {
-            println!("{:?}", program_header);
-        }
-        for section in elf.section_iter() {
-            println!("{:?}", section);
-        }
+        let mut set = MemorySet::from(&elf);
+//        set.map(mc);
         unimplemented!();
     }
 }
 
 use memory::{MemorySet, MemoryArea};
 
-fn new_memory_set_from_elf(elf: ElfFile, mc: &mut MemoryController) -> MemorySet {
+impl<'a> From<&'a ElfFile<'a>> for MemorySet {
+    fn from(elf: &'a ElfFile<'a>) -> Self {
         use xmas_elf::program::ProgramHeader;
 
-    let mut set = MemorySet::new(mc);
+        let mut set = MemorySet::new();
         for ph in elf.program_iter() {
             match ph {
                 ProgramHeader::Ph32(ph) => unimplemented!(),
@@ -76,6 +74,7 @@ fn new_memory_set_from_elf(elf: ElfFile, mc: &mut MemoryController) -> MemorySet
                     set.push(MemoryArea {
                         start_addr: ph.virtual_addr as usize,
                         end_addr: (ph.virtual_addr + ph.mem_size) as usize,
+                        phys_start_addr: None,
                         flags: ph.flags.0,  // TODO: handle it
                         name: "",
                         mapped: false,
@@ -85,3 +84,4 @@ fn new_memory_set_from_elf(elf: ElfFile, mc: &mut MemoryController) -> MemorySet
         }
         set
     }
+}