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Allow thread control block to be moved

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This commit is contained in:
Jeremy Soller 2016-09-11 18:25:05 -06:00
parent f0431f4de1
commit bed09d0518
2 changed files with 13 additions and 15 deletions
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13
arch/x86_64/src/paging/mod.rs
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@ -1,6 +1,7 @@
//! # Paging
//! Some code was borrowed from [Phil Opp's Blog](http://os.phil-opp.com/modifying-page-tables.html)
use core::mem;
use core::ops::{Deref, DerefMut};
use x86::{msr, tlb};
@ -22,7 +23,9 @@ pub const ENTRY_COUNT: usize = 512;
pub const PAGE_SIZE: usize = 4096;
/// Initialize paging
pub unsafe fn init(stack_start: usize, stack_end: usize) -> ActivePageTable {
///
/// Returns page table and thread control block offset
pub unsafe fn init(stack_start: usize, stack_end: usize) -> (ActivePageTable, usize) {
extern {
/// The starting byte of the text (code) data segment.
static mut __text_start: u8;
@ -145,9 +148,11 @@ pub unsafe fn init(stack_start: usize, stack_end: usize) -> ActivePageTable {
}
// Map and clear TBSS
let tcb_offset;
{
let start = & __tbss_start as *const _ as usize;
let end = & __tbss_end as *const _ as usize;
tcb_offset = end - mem::size_of::<usize>();
if end > start {
let start_page = Page::containing_address(VirtualAddress::new(start));
let end_page = Page::containing_address(VirtualAddress::new(end - 1));
@ -157,13 +162,13 @@ pub unsafe fn init(stack_start: usize, stack_end: usize) -> ActivePageTable {
::externs::memset(page.start_address().get() as *mut u8, 0, 4096);
}
*(end as *mut usize).offset(-1) = end;
*(tcb_offset as *mut usize) = end;
}
}
active_table.flush_all();
active_table
(active_table, tcb_offset)
}
pub struct ActivePageTable {
@ -217,7 +222,7 @@ impl ActivePageTable {
where F: FnOnce(&mut Mapper)
{
use x86::controlregs;
{
let backup = Frame::containing_address(PhysicalAddress::new(unsafe { controlregs::cr3() } as usize));