Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: - [High] Strict `usize` alignment check in `Region::ptr_try_from_raw_parts_mut` breaks driver probes for valid 4-byte aligned MMIO mappings. --
commit facc65605656f1d5585f26a25f200941e6ae7d73 Author: Gary Guo <[email protected]> rust: io: generalize MmioRaw to pointer to arbitrary type This commit generalizes MmioRaw to represent an untyped I/O region using the dynamically-sized Region<SIZE> type. It renames the maxsize method to size and implements Clone, Copy, Send, and Sync manually. > diff --git a/rust/kernel/io.rs b/rust/kernel/io.rs > index d57df2a072a0e..c9533d3f003ba 100644 > --- a/rust/kernel/io.rs > +++ b/rust/kernel/io.rs [ ... ] > @@ -90,37 +90,67 @@ fn size(p: *const Self) -> usize { [ ... ] > +impl<const SIZE: usize> MmioRaw<Region<SIZE>> { > + /// Create a `MmioRaw` representing a I/O region with given size. > + /// > + /// The size is checked against the minimum size specified via const > generics. > + #[inline] > + pub fn new_region(addr: usize, size: usize) -> Result<Self> { > + Ok(Self { > + ptr: > Region::ptr_try_from_raw_parts_mut(core::ptr::without_provenance_mut(addr), > size)?, [Severity: High] Does this alignment check break driver probes for standard 4-byte aligned MMIO mappings on 64-bit architectures? Looking at Region::ptr_try_from_raw_parts_mut(), it enforces a strict usize alignment on the base address: rust/kernel/io.rs:Region::ptr_try_from_raw_parts_mut() { ... if size < SIZE || base.align_offset(size_of::<usize>()) != 0 { return Err(EINVAL); } ... } On 64-bit systems, this forces an 8-byte alignment requirement. However, PCI 32-bit BARs and SoC IP block MMIO regions frequently have 4-byte aligned physical base addresses. When mapped with ioremap() or pci_iomap(), the resulting virtual address retains this 4-byte alignment offset, which would fail the 8-byte alignment check here. Consequently, standard hardware mapping operations in devres::IoMem::new(), IoMem::ioremap(), and pci::Bar::new() will unconditionally fail at runtime with -EINVAL during driver probe for these devices, making them unusable. > + }) > } > +} -- Sashiko AI review ยท https://sashiko.dev/#/patchset/[email protected]?part=5
