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[v0.9] Fix map errors during kernel loading #422

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merged 3 commits into from
Feb 16, 2024
Merged

[v0.9] Fix map errors during kernel loading #422

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f317b0d
Don't error if a kernel page is already mapped to the correct frame
phil-opp Feb 16, 2024
949a297
Fix: unmap temp page again to enable multiple bss-like sections
phil-opp Feb 16, 2024
9209b0c
Update changelog for #422
phil-opp Feb 16, 2024
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5 changes: 5 additions & 0 deletions Changelog.md
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Original file line number Diff line number Diff line change
@@ -1,5 +1,10 @@
# Unreleased


- [Fix map errors during kernel loading](https://github.com/rust-osdev/bootloader/pull/422)
- Don't error if a kernel page is already mapped to the correct frame
- Fix: unmap temp page again to enable multiple bss-like sections

# 0.9.25 – 2024-02-16

- [Fix data layout for custom targets for LLVM 18](https://github.com/rust-osdev/bootloader/pull/421)
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18 changes: 15 additions & 3 deletions src/page_table.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -96,8 +96,15 @@ pub(crate) fn map_segment(
for frame in PhysFrame::range_inclusive(start_frame, end_frame) {
let offset = frame - start_frame;
let page = start_page + offset;
unsafe { map_page(page, frame, page_table_flags, page_table, frame_allocator)? }
.flush();
match unsafe {
map_page(page, frame, page_table_flags, page_table, frame_allocator)
} {
Ok(flusher) => flusher.flush(),
Err(MapToError::PageAlreadyMapped(to)) if to == frame => {
// nothing to do, page is already mapped to the correct frame
}
Err(err) => return Err(err),
}
}

if mem_size > file_size {
Expand All @@ -117,7 +124,7 @@ pub(crate) fn map_segment(
unsafe {
map_page(
temp_page.clone(),
new_frame.clone(),
new_frame,
page_table_flags,
page_table,
frame_allocator,
Expand Down Expand Up @@ -145,6 +152,11 @@ pub(crate) fn map_segment(
});
}

// unmap temp page again
let (new_frame, flusher) = page_table.unmap(temp_page).unwrap();
flusher.flush();

// map last page to new frame
unsafe {
map_page(
last_page,
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