forked from M-Labs/artiq-zynq
40 lines
1.4 KiB
Rust
40 lines
1.4 KiB
Rust
use libcortex_a9::mmu::{AccessPermissions, L1_PAGE_SIZE, L1Table};
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/// Symbols defined by the linker script
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extern "C" {
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static __text_start: usize;
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static __text_end: usize;
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static __rodata_start: usize;
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static __rodata_end: usize;
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}
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/// Apply basic memory protection to the regions defined by the linker
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/// script for the runtime on core 0.
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///
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/// Therefore these regions need to be aligned to 1 MB.
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pub fn setup() {
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let text_start = unsafe { &__text_start as *const _ as usize };
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let text_end = unsafe { &__text_end as *const _ as usize };
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let rodata_start = unsafe { &__rodata_start as *const _ as usize };
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let rodata_end = unsafe { &__rodata_end as *const _ as usize };
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let l1table = L1Table::get();
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for addr in (0..0xFFFF_FFFF).step_by(L1_PAGE_SIZE) {
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l1table.update(addr as *const usize, |l1section| {
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if addr >= text_start && addr < text_end {
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// Code: R-X
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l1section.access = AccessPermissions::ReadOnly;
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l1section.exec = true;
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} else if addr >= rodata_start && addr < rodata_end {
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// Data: R--
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l1section.access = AccessPermissions::ReadOnly;
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l1section.exec = false;
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} else {
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// Everything else: RW-
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l1section.access = AccessPermissions::FullAccess;
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l1section.exec = false;
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}
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});
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}
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}
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