fix #13 page fault

Author: qiaoqiming

os/src/memory/memory_set/area.rs

@@ -50,12 +50,15 @@ impl MemoryArea {
     pub fn page_copy(&self, pt: &mut PageTableImpl, src: usize, length: usize) {
         let mut l = length;
         let mut s = src;
+        let mut offset = self.start % PAGE_SIZE;
         for page in PageRange::new(self.start, self.end) {
+            let copy_size = PAGE_SIZE-offset;
             self.handler
-                .page_copy(pt, page, s, if l < PAGE_SIZE { l } else { PAGE_SIZE });
-            s += PAGE_SIZE;
-            if l >= PAGE_SIZE {
-                l -= PAGE_SIZE;
+                .page_copy(pt, page, offset, s, if l < copy_size { l } else { copy_size });
+            offset = 0;
+            s += copy_size;
+            if l >= copy_size {
+                l -= copy_size;
             }
         }
     }

os/src/memory/memory_set/handler.rs

@@ -10,7 +10,7 @@ pub trait MemoryHandler: Debug + 'static {
     fn box_clone(&self) -> Box<dyn MemoryHandler>;
     fn map(&self, pt: &mut PageTableImpl, va: usize, attr: &MemoryAttr);
     fn unmap(&self, pt: &mut PageTableImpl, va: usize);
-    fn page_copy(&self, pt: &mut PageTableImpl, va: usize, src: usize, length: usize);
+    fn page_copy(&self, pt: &mut PageTableImpl, va: usize, va_offset: usize, src: usize, length: usize);
 }
 
 impl Clone for Box<dyn MemoryHandler> {
@@ -39,12 +39,12 @@ impl MemoryHandler for Linear {
     fn unmap(&self, pt: &mut PageTableImpl, va: usize) {
         pt.unmap(va);
     }
-    fn page_copy(&self, pt: &mut PageTableImpl, va: usize, src: usize, length: usize) {
+    fn page_copy(&self, pt: &mut PageTableImpl, va: usize, va_offset: usize, src: usize, length: usize) {
         let pa = pt.get_entry(va).expect("get pa error!").0.addr().as_usize();
         assert!(va == access_pa_via_va(pa));
         assert!(va == pa + self.offset);
         unsafe {
-            let dst = core::slice::from_raw_parts_mut(va as *mut u8, PAGE_SIZE);
+            let dst = core::slice::from_raw_parts_mut((va+va_offset) as *mut u8, PAGE_SIZE);
             if length > 0 {
                 let src = core::slice::from_raw_parts(src as *const u8, PAGE_SIZE);
                 dst[..length].clone_from_slice(&src[..length]);
@@ -78,10 +78,10 @@ impl MemoryHandler for ByFrame {
     fn unmap(&self, pt: &mut PageTableImpl, va: usize) {
         pt.unmap(va);
     }
-    fn page_copy(&self, pt: &mut PageTableImpl, va: usize, src: usize, length: usize) {
+    fn page_copy(&self, pt: &mut PageTableImpl, va: usize, va_offset: usize, src: usize, length: usize) {
         let pa = pt.get_entry(va).expect("get pa error!").0.addr().as_usize();
         unsafe {
-            let dst = core::slice::from_raw_parts_mut(access_pa_via_va(pa) as *mut u8, PAGE_SIZE);
+            let dst = core::slice::from_raw_parts_mut((access_pa_via_va(pa)+va_offset) as *mut u8, PAGE_SIZE);
             if length > 0 {
                 let src = core::slice::from_raw_parts(src as *const u8, PAGE_SIZE);
                 dst[..length].clone_from_slice(&src[..length]);