Crate memory_set
source ·Expand description
§memory_set
+
+
Data structures and operations for managing memory mappings.
+It is useful to implement mmap and munmap.
§Examples
+use memory_addr::{va, va_range, VirtAddr};
+use memory_set::{MappingBackend, MemoryArea, MemorySet};
+
+const MAX_ADDR: usize = 0x10000;
+
+/// A mock memory flags.
+type MockFlags = u8;
+/// A mock page table, which is a simple array that maps addresses to flags.
+type MockPageTable = [MockFlags; MAX_ADDR];
+
+/// A mock mapping backend that manipulates the page table on `map` and `unmap`.
+#[derive(Clone)]
+struct MockBackend;
+
+let mut pt = [0; MAX_ADDR];
+let mut memory_set = MemorySet::<MockFlags, MockPageTable, MockBackend>::new();
+
+// Map [0x1000..0x5000).
+memory_set.map(
+ /* area: */ MemoryArea::new(va!(0x1000), 0x4000, 1, MockBackend),
+ /* page_table: */ &mut pt,
+ /* unmap_overlap */ false,
+).unwrap();
+// Unmap [0x2000..0x4000), will split the area into two parts.
+memory_set.unmap(va!(0x2000), 0x2000, &mut pt).unwrap();
+
+let areas = memory_set.iter().collect::<Vec<_>>();
+assert_eq!(areas.len(), 2);
+assert_eq!(areas[0].va_range(), va_range!(0x1000..0x2000));
+assert_eq!(areas[1].va_range(), va_range!(0x4000..0x5000));
+
+// Underlying operations to do when manipulating mappings.
+impl MappingBackend<MockFlags, MockPageTable> for MockBackend {
+ fn map(&self, start: VirtAddr, size: usize, flags: MockFlags, pt: &mut MockPageTable) -> bool {
+ for entry in pt.iter_mut().skip(start.as_usize()).take(size) {
+ if *entry != 0 {
+ return false;
+ }
+ *entry = flags;
+ }
+ true
+ }
+
+ fn unmap(&self, start: VirtAddr, size: usize, pt: &mut MockPageTable) -> bool {
+ for entry in pt.iter_mut().skip(start.as_usize()).take(size) {
+ if *entry == 0 {
+ return false;
+ }
+ *entry = 0;
+ }
+ true
+ }
+}Structs§
- A memory area represents a continuous range of virtual memory with the same +flags.
- A container that maintains memory mappings (
MemoryArea).
Enums§
- Error type for memory mapping operations.
Traits§
- Underlying operations to do when manipulating mappings within the specific +memory area.
Type Aliases§
- A
Resulttype withMappingErroras the error type.