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74 lines
2.0 KiB
Rust
74 lines
2.0 KiB
Rust
// SPDX-License-Identifier: MIT OR Apache-2.0
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//
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// Copyright (c) 2018-2020 Andre Richter <andre.o.richter@gmail.com>
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//! Memory Management.
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pub mod mmu;
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use core::ops::RangeInclusive;
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//--------------------------------------------------------------------------------------------------
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// Public Code
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//--------------------------------------------------------------------------------------------------
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/// Zero out an inclusive memory range.
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///
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/// # Safety
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///
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/// - `range.start` and `range.end` must be valid.
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/// - `range.start` and `range.end` must be `T` aligned.
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pub unsafe fn zero_volatile<T>(range: RangeInclusive<*mut T>)
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where
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T: From<u8>,
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{
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let mut ptr = *range.start();
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let end_inclusive = *range.end();
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loop {
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core::ptr::write_volatile(ptr, T::from(0));
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ptr = ptr.offset(1);
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if ptr > end_inclusive {
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break;
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}
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}
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}
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//--------------------------------------------------------------------------------------------------
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// Testing
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//--------------------------------------------------------------------------------------------------
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#[cfg(test)]
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mod tests {
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use super::*;
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use test_macros::kernel_test;
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/// Check `zero_volatile()`.
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#[kernel_test]
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fn zero_volatile_works() {
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let mut x: [usize; 3] = [10, 11, 12];
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let x_range = x.as_mut_ptr_range();
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let x_range_inclusive =
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RangeInclusive::new(x_range.start, unsafe { x_range.end.offset(-1) });
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unsafe { zero_volatile(x_range_inclusive) };
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assert_eq!(x, [0, 0, 0]);
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}
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/// Check `bss` section layout.
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#[kernel_test]
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fn bss_section_is_sane() {
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use crate::bsp::memory::bss_range_inclusive;
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use core::mem;
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let start = *bss_range_inclusive().start() as usize;
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let end = *bss_range_inclusive().end() as usize;
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assert_eq!(start % mem::size_of::<usize>(), 0);
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assert_eq!(end % mem::size_of::<usize>(), 0);
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assert!(end >= start);
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}
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}
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