forked from AbleOS/holey-bytes
Fixed memory (un)mapping
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parent
19df4538d7
commit
1ed153a9a2
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@ -10,26 +10,42 @@ use {
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fuzz_target!(|data: &[u8]| {
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if let Ok(mut vm) = Vm::<_, 16384>::new_validated(data, TestTrapHandler, Default::default()) {
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let page = Box::into_raw(Box::<Page>::default());
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unsafe {
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vm.memory
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.map(
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page.cast(),
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0,
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hbvm::mem::paging::Permission::Write,
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PageSize::Size4K,
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)
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.unwrap()
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};
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// Alloc and map some memory
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let pages = [
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alloc_and_map(&mut vm.memory, 0),
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alloc_and_map(&mut vm.memory, 4096),
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];
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// Run VM
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let _ = vm.run();
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vm.memory.unmap(0).unwrap();
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let _ = unsafe { Box::from_raw(page) };
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// Unmap and dealloc the memory
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for (i, page) in pages.into_iter().enumerate() {
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unmap_and_dealloc(&mut vm.memory, page, i as u64 * 4096);
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}
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}
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});
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fn alloc_and_map(memory: &mut Memory, at: u64) -> *mut u8 {
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let ptr = Box::into_raw(Box::<Page>::default()).cast();
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unsafe {
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memory
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.map(
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ptr,
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at,
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hbvm::mem::paging::Permission::Write,
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PageSize::Size4K,
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)
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.unwrap()
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};
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ptr
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}
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fn unmap_and_dealloc(memory: &mut Memory, ptr: *mut u8, from: u64) {
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memory.unmap(from).unwrap();
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let _ = unsafe { Box::from_raw(ptr.cast::<Page>()) };
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}
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#[repr(align(4096))]
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struct Page([u8; 4096]);
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impl Default for Page {
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@ -1,7 +1,7 @@
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//! Program memory implementation
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pub mod paging;
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pub mod bmc;
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pub mod paging;
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mod pfhandler;
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@ -58,13 +58,13 @@ impl Memory {
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// Decide on what level depth are we going
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let lookup_depth = match pagesize {
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PageSize::Size4K => 4,
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PageSize::Size2M => 3,
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PageSize::Size4K => 0,
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PageSize::Size2M => 1,
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PageSize::Size1G => 2,
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};
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// Walk pagetable levels
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for lvl in (0..lookup_depth).rev() {
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for lvl in (lookup_depth..5).rev() {
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let entry = (*current_pt)
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.table
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.get_unchecked_mut(addr_extract_index(target, lvl));
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@ -94,7 +94,7 @@ impl Memory {
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let node = (*current_pt)
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.table
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.get_unchecked_mut(addr_extract_index(target, 4 - lookup_depth));
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.get_unchecked_mut(addr_extract_index(target, lookup_depth));
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// Check if node is not mapped
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if node.permission() != Permission::Empty {
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@ -114,6 +114,7 @@ impl Memory {
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/// just should be ignored.
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#[cfg(feature = "alloc")]
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pub fn unmap(&mut self, addr: u64) -> Result<(), NothingToUnmap> {
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extern crate std;
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let mut current_pt = self.root_pt;
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let mut page_tables = [core::ptr::null_mut(); 5];
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@ -152,9 +153,7 @@ impl Memory {
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unsafe {
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let children = &mut (*(*entry).ptr()).pt.childen;
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// Decrease children count
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*children -= 1;
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*children -= 1; // Decrease children count
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// If there are no children, deallocate.
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if *children == 0 {
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@ -162,6 +161,8 @@ impl Memory {
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// Zero visited entry
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core::ptr::write_bytes(entry, 0, 1);
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} else {
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break;
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}
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}
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}
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