Store context memory information

kernel/context/memory.rs

@@ -0,0 +1,70 @@
+use arch::paging::{ActivePageTable, Page, PageIter, VirtualAddress};
+use arch::paging::entry::EntryFlags;
+
+#[derive(Debug)]
+pub struct Memory {
+    start: VirtualAddress,
+    size: usize,
+    flags: EntryFlags
+}
+
+impl Memory {
+    pub fn new(start: VirtualAddress, size: usize, flags: EntryFlags) -> Self {
+        let mut memory = Memory {
+            start: start,
+            size: size,
+            flags: flags
+        };
+
+        memory.map(true);
+
+        memory
+    }
+
+    pub fn pages(&self) -> PageIter {
+        let start_page = Page::containing_address(self.start);
+        let end_page = Page::containing_address(VirtualAddress::new(self.start.get() + self.size - 1));
+        Page::range_inclusive(start_page, end_page)
+    }
+
+    pub fn map(&mut self, flush: bool) {
+        let mut active_table = unsafe { ActivePageTable::new() };
+
+        for page in self.pages() {
+            active_table.map(page, self.flags);
+            if flush {
+                active_table.flush(page);
+            }
+        }
+    }
+
+    pub fn unmap(&mut self, flush: bool) {
+        let mut active_table = unsafe { ActivePageTable::new() };
+
+        for page in self.pages() {
+            active_table.unmap(page);
+            if flush {
+                active_table.flush(page);
+            }
+        }
+    }
+
+    pub fn remap(&mut self, new_flags: EntryFlags, flush: bool) {
+        let mut active_table = unsafe { ActivePageTable::new() };
+
+        self.flags = new_flags;
+
+        for page in self.pages() {
+            active_table.remap(page, self.flags);
+            if flush {
+                active_table.flush(page);
+            }
+        }
+    }
+}
+
+impl Drop for Memory {
+    fn drop(&mut self) {
+        self.unmap(true);
+    }
+}

kernel/context/mod.rs

@@ -13,6 +13,9 @@ use syscall::{Error, Result};
 /// File operations
 pub mod file;
 
+/// Memory operations
+pub mod memory;
+
 /// Limit on number of contexts
 pub const CONTEXT_MAX_CONTEXTS: usize = 65536;
 
@@ -171,6 +174,10 @@ pub struct Context {
     pub arch: ArchContext,
     /// Kernel stack
     pub kstack: Option<Box<[u8]>>,
+    /// Executable image
+    pub image: Vec<memory::Memory>,
+    /// User stack
+    pub stack: Option<memory::Memory>,
     /// The open files in the scheme
     pub files: Vec<Option<file::File>>
 }
@@ -184,6 +191,8 @@ impl Context {
             blocked: true,
             arch: ArchContext::new(),
             kstack: None,
+            image: Vec::new(),
+            stack: None,
             files: Vec::new()
         }
     }

kernel/elf.rs

@@ -11,8 +11,10 @@ use goblin::elf32::{header, program_header};
 use goblin::elf64::{header, program_header};
 
 use arch::externs::{memcpy, memset};
-use arch::paging::{entry, ActivePageTable, Page, VirtualAddress};
+use arch::paging::{entry, VirtualAddress};
 use arch::start::usermode;
+use context;
+use syscall::{Error, Result as SysResult};
 
 /// An ELF executable
 pub struct Elf<'a> {
@@ -51,74 +53,67 @@ impl<'a> Elf<'a> {
     }
 
     /// Test function to run. Remove and replace with proper syscall
-    pub fn run(self) {
-        let mut active_table = unsafe { ActivePageTable::new() };
+    pub fn run(self) -> SysResult<!> {
+        let stack_addr = 0x80000000;
+        let stack_size = 64 * 1024;
+        {
+            let contexts = context::contexts();
+            let context_lock = contexts.current().ok_or(Error::NoProcess)?;
+            let mut context = context_lock.write();
 
-        for segment in self.segments() {
-            if segment.p_type == program_header::PT_LOAD {
-                let start_page = Page::containing_address(VirtualAddress::new(segment.p_vaddr as usize));
-                let end_page = Page::containing_address(VirtualAddress::new((segment.p_vaddr + segment.p_memsz) as usize));
+            // Unmap previous image and stack
+            context.image.clear();
+            context.stack.take();
 
-                for page in Page::range_inclusive(start_page, end_page) {
-                    if active_table.translate_page(page).is_some() {
-                        //TODO panic!("Elf::run: still mapped: {:?}", page);
-                        active_table.unmap(page);
+            for segment in self.segments() {
+                if segment.p_type == program_header::PT_LOAD {
+                    let mut memory = context::memory::Memory::new(
+                        VirtualAddress::new(segment.p_vaddr as usize),
+                        segment.p_memsz as usize,
+                        entry::NO_EXECUTE | entry::WRITABLE);
+
+                    unsafe {
+                        // Copy file data
+                        memcpy(segment.p_vaddr as *mut u8,
+                                (self.data.as_ptr() as usize + segment.p_offset as usize) as *const u8,
+                                segment.p_filesz as usize);
+                        // Set BSS
+                        memset((segment.p_vaddr + segment.p_filesz) as *mut u8,
+                                0,
+                                (segment.p_memsz - segment.p_filesz) as usize);
                     }
-                    active_table.map(page, entry::NO_EXECUTE | entry::WRITABLE);
-                }
-                active_table.flush_all();
 
-                unsafe {
-                    // Copy file data
-                    memcpy(segment.p_vaddr as *mut u8,
-                            (self.data.as_ptr() as usize + segment.p_offset as usize) as *const u8,
-                            segment.p_filesz as usize);
-                    // Set BSS
-                    memset((segment.p_vaddr + segment.p_filesz) as *mut u8,
-                            0,
-                            (segment.p_memsz - segment.p_filesz) as usize);
-                }
+                    let mut flags = entry::NO_EXECUTE | entry::USER_ACCESSIBLE;
 
-                let mut flags = entry::NO_EXECUTE | entry::USER_ACCESSIBLE;
+                    if segment.p_flags & program_header::PF_R == program_header::PF_R {
+                        flags.insert(entry::PRESENT);
+                    }
 
-                if segment.p_flags & program_header::PF_R == program_header::PF_R {
-                    flags.insert(entry::PRESENT);
-                }
+                    // W ^ X. If it is executable, do not allow it to be writable, even if requested
+                    if segment.p_flags & program_header::PF_X == program_header::PF_X {
+                        flags.remove(entry::NO_EXECUTE);
+                    } else if segment.p_flags & program_header::PF_W == program_header::PF_W {
+                        flags.insert(entry::WRITABLE);
+                    }
 
-                // W ^ X. If it is executable, do not allow it to be writable, even if requested
-                if segment.p_flags & program_header::PF_X == program_header::PF_X {
-                    flags.remove(entry::NO_EXECUTE);
-                } else if segment.p_flags & program_header::PF_W == program_header::PF_W {
-                    flags.insert(entry::WRITABLE);
-                }
+                    memory.remap(flags, true);
 
-                for page in Page::range_inclusive(start_page, end_page) {
-                    active_table.remap(page, flags);
+                    context.image.push(memory);
                 }
-                active_table.flush_all();
             }
-        }
 
-        // Map stack
-        let start_page = Page::containing_address(VirtualAddress::new(0x80000000));
-        let end_page = Page::containing_address(VirtualAddress::new(0x80000000 + 64*1024 - 1));
+            // Map stack
+            context.stack = Some(context::memory::Memory::new(
+                VirtualAddress::new(stack_addr),
+                stack_size,
+                entry::NO_EXECUTE | entry::WRITABLE | entry::USER_ACCESSIBLE));
 
-        for page in Page::range_inclusive(start_page, end_page) {
-            if active_table.translate_page(page).is_some() {
-                //TODO panic!("Elf::run: still mapped: {:?}", page);
-                active_table.unmap(page);
-            }
-            active_table.map(page, entry::NO_EXECUTE | entry::WRITABLE | entry::USER_ACCESSIBLE);
-        }
-        active_table.flush_all();
-
-        unsafe {
             // Clear stack
-            memset(0x80000000 as *mut u8, 0, 64 * 1024);
-
-            // Go to usermode
-            usermode(self.entry(), 0x80000000 + 64*1024 - 256);
+            unsafe { memset(stack_addr as *mut u8, 0, stack_size); }
         }
+
+        // Go to usermode
+        unsafe { usermode(self.entry(), stack_addr + stack_size - 256); }
     }
 }
 

kernel/lib.rs

@@ -70,6 +70,7 @@
 #![feature(const_fn)]
 #![feature(drop_types_in_const)]
 #![feature(question_mark)]
+#![feature(never_type)]
 #![feature(thread_local)]
 #![no_std]
 

kernel/syscall/process.rs

@@ -93,10 +93,7 @@ pub fn exec(path: &[u8], _args: &[[usize; 2]]) -> Result<usize> {
     let _ = syscall::close(file);
 
     match elf::Elf::from(&data) {
-        Ok(elf) => {
-            elf.run();
-            Ok(0)
-        },
+        Ok(elf) => elf.run().and(Ok(0)),
         Err(err) => {
             println!("failed to execute {}: {}", unsafe { str::from_utf8_unchecked(path) }, err);
             Err(Error::NoExec)