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Revise IoMem::resize into IoMem::slice

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This commit is contained in:
Ruihan Li
2024-08-24 12:56:08 +08:00
committed by Tate, Hongliang Tian
parent c8ba695c85
commit cefeea7b50
3 changed files with 19 additions and 38 deletions
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35
ostd/src/io_mem.rs
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@ -34,8 +34,8 @@ impl IoMem {
/// - The given physical address range must be in the I/O memory region.
/// - Reading from or writing to I/O memory regions may have side effects. Those side effects
/// must not cause soundness problems (e.g., they must not corrupt the kernel memory).
pub(crate) unsafe fn new(range: Range<Paddr>) -> IoMem {
IoMem {
pub(crate) unsafe fn new(range: Range<Paddr>) -> Self {
Self {
virtual_address: paddr_to_vaddr(range.start),
limit: range.len(),
}
@ -51,29 +51,20 @@ impl IoMem {
self.limit
}
/// Resizes the I/O memory region to the new `range`.
/// Slices the `IoMem`, returning another `IoMem` representing the subslice.
///
/// # Errors
/// # Panics
///
/// Returns an error if the new `range` is not within the current range.
pub fn resize(&mut self, range: Range<Paddr>) -> Result<()> {
let start_vaddr = paddr_to_vaddr(range.start);
let virtual_end = self
.virtual_address
.checked_add(self.limit)
.ok_or(Error::Overflow)?;
if start_vaddr < self.virtual_address || start_vaddr >= virtual_end {
return Err(Error::InvalidArgs);
/// This method will panic if the range is empty or out of bounds.
pub fn slice(&self, range: Range<usize>) -> Self {
// This ensures `range.start < range.end` and `range.end <= limit`.
assert!(!range.is_empty() && range.end <= self.limit);
// We've checked the range is in bounds, so we can construct the new `IoMem` safely.
Self {
virtual_address: self.virtual_address + range.start,
limit: range.end - range.start,
}
let end_vaddr = start_vaddr
.checked_add(range.len())
.ok_or(Error::Overflow)?;
if end_vaddr <= self.virtual_address || end_vaddr > virtual_end {
return Err(Error::InvalidArgs);
}
self.virtual_address = start_vaddr;
self.limit = range.len();
Ok(())
}
}