Andrey Turkin
a96ea6f5f3
Before this commit, RMM assumed base physical address was presented in PTE as is, i.e. physical page address was shifted exactly to PAGE_SHIFT, so physical address can be extracted from PTE by simply masking off some bits and can be placed in PTE by simple addition/OR. This is not the case for RISC-V which has 4Kb base page so 12 bits PAGE_SHIFT, yet physical page address is only shifted 10 bits in PTE. This commit removes this assumption. NOTE: This commit changes meaning of constants: * ENTRY_ADDRESS_SIZE from "total physical size in bytes" to "total physical size in PAGES" * ENTRY_ADDRESS_MASK from "mask of physical bits in PTE" to "mask of physical bits starting at bit 0"
60 lines
1.4 KiB
Rust
60 lines
1.4 KiB
Rust
use core::marker::PhantomData;
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use crate::{Arch, PageFlags, PhysicalAddress};
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#[derive(Clone, Copy, Debug)]
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pub struct PageEntry<A> {
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data: usize,
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phantom: PhantomData<A>,
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}
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impl<A: Arch> PageEntry<A> {
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#[inline(always)]
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pub fn new(address: usize, flags: usize) -> Self {
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let data = (((address >> A::PAGE_SHIFT) & A::ENTRY_ADDRESS_MASK) << A::ENTRY_ADDRESS_SHIFT)
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| flags;
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Self::from_data(data)
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}
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#[inline(always)]
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pub fn from_data(data: usize) -> Self {
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Self {
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data,
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phantom: PhantomData,
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}
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}
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#[inline(always)]
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pub fn data(&self) -> usize {
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self.data
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}
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#[inline(always)]
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pub fn address(&self) -> Result<PhysicalAddress, PhysicalAddress> {
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let addr = PhysicalAddress(
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((self.data >> A::ENTRY_ADDRESS_SHIFT) & A::ENTRY_ADDRESS_MASK) << A::PAGE_SHIFT,
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);
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if self.present() {
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Ok(addr)
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} else {
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Err(addr)
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}
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}
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#[inline(always)]
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pub fn flags(&self) -> PageFlags<A> {
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unsafe { PageFlags::from_data(self.data & A::ENTRY_FLAGS_MASK) }
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}
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#[inline(always)]
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pub fn set_flags(&mut self, flags: PageFlags<A>) {
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self.data &= !A::ENTRY_FLAGS_MASK;
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self.data |= flags.data();
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}
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#[inline(always)]
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pub fn present(&self) -> bool {
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self.data & A::ENTRY_FLAG_PRESENT != 0
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}
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}
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