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Removed unsafe for id_map_range, added comments

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This commit is contained in:
Stephen Marz 2019-10-09 19:44:39 -04:00
parent 037e7044ac
commit d81c619e60
1 changed files with 9 additions and 8 deletions
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9
risc_v/ch3/src/lib.rs
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@ -87,14 +87,15 @@ extern "C"
static KERNEL_STACK: usize;
static mut KERNEL_TABLE: usize;
}
/// Identity map range
/// Takes a contiguous allocation of memory and maps it using PAGE_SIZE
/// This assumes that start <= end
pub fn id_map_range(root: &mut page::Table, start: usize, end: usize, bits: i64) {
unsafe {
let num_pages = (page::align_val(end, 12) - (start & !(page::PAGE_SIZE-1))) / page::PAGE_SIZE;
for i in 0..num_pages {
let m = (start & !(page::PAGE_SIZE-1)) + (i << 12);
page::map(root, m, m, bits);
}
}
}
// ///////////////////////////////////
// / ENTRY POINT
@ -114,9 +115,9 @@ fn kinit() -> usize {
let root_ptr = kmem::get_page_table();
let root_u = root_ptr as usize;
let mut root = unsafe { root_ptr.as_mut().unwrap() };
let t = kmem::get_head() as usize;
let kheap_head = kmem::get_head() as usize;
let total_pages = kmem::get_num_allocations();
id_map_range(&mut root, t, t + (total_pages << 12), page::EntryBits::ReadWrite.val());
id_map_range(&mut root, kheap_head, kheap_head + (total_pages << 12), page::EntryBits::ReadWrite.val());
unsafe {
// Map executable section
id_map_range(&mut root, TEXT_START, TEXT_END, page::EntryBits::ReadExecute.val());