forked from AbleOS/holey-bytes
115 lines
2.6 KiB
Rust
115 lines
2.6 KiB
Rust
//! Memory implementations
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pub mod softpaging;
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pub(crate) mod addr;
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pub use addr::Address;
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use crate::utils::impl_display;
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/// Load-store memory access
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pub trait Memory {
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/// Load data from memory on address
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///
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/// # Safety
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/// - Shall not overrun the buffer
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unsafe fn load(
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&mut self,
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addr: Address,
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target: *mut u8,
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count: usize,
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) -> Result<(), LoadError>;
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/// Store data to memory on address
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///
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/// # Safety
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/// - Shall not overrun the buffer
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unsafe fn store(
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&mut self,
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addr: Address,
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source: *const u8,
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count: usize,
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) -> Result<(), StoreError>;
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/// Read from program memory to execute
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///
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/// # Safety
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/// - Data read have to be valid
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unsafe fn prog_read<T: Copy>(&mut self, addr: Address) -> T;
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}
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/// Unhandled load access trap
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#[derive(Clone, Copy, Debug, PartialEq, Eq)]
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pub struct LoadError(pub Address);
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impl_display!(for LoadError =>
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|LoadError(a)| "Load access error at address {a}",
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);
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/// Unhandled store access trap
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#[derive(Clone, Copy, Debug, PartialEq, Eq)]
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pub struct StoreError(pub Address);
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impl_display!(for StoreError =>
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|StoreError(a)| "Load access error at address {a}",
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);
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/// Reason to access memory
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#[derive(Clone, Copy, Debug, PartialEq, Eq)]
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pub enum MemoryAccessReason {
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/// Memory was accessed for load (read)
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Load,
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/// Memory was accessed for store (write)
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Store,
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}
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impl_display!(for MemoryAccessReason => match {
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Self::Load => const "Load";
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Self::Store => const "Store";
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});
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impl From<LoadError> for crate::VmRunError {
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fn from(value: LoadError) -> Self {
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Self::LoadAccessEx(value.0)
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}
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}
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impl From<StoreError> for crate::VmRunError {
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fn from(value: StoreError) -> Self {
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Self::StoreAccessEx(value.0)
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}
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}
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#[derive(Default)]
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pub struct HostMemory;
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impl Memory for HostMemory {
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#[inline]
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unsafe fn load(
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&mut self,
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addr: Address,
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target: *mut u8,
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count: usize,
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) -> Result<(), LoadError> {
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unsafe { core::ptr::copy(addr.get() as *const u8, target, count) }
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Ok(())
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}
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#[inline]
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unsafe fn store(
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&mut self,
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addr: Address,
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source: *const u8,
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count: usize,
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) -> Result<(), StoreError> {
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debug_assert!(addr.get() != 0);
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debug_assert!(!source.is_null());
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unsafe { core::ptr::copy(source, addr.get() as *mut u8, count) }
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Ok(())
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}
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#[inline]
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unsafe fn prog_read<T: Copy>(&mut self, addr: Address) -> T {
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debug_assert!(addr.get() != 0);
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unsafe { core::ptr::read(addr.get() as *const T) }
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}
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}
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