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Setup TSS, using thread local storage

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This commit is contained in:
Jeremy Soller 2016-08-22 14:53:03 -06:00
parent 3eca1e3451
commit 4ced24e8d1
2 changed files with 9 additions and 5 deletions
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10
arch/x86_64/src/gdt.rs
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@ -89,7 +89,7 @@ pub static mut TSS: TaskStateSegment = TaskStateSegment {
}; };
/// Initialize GDT on the BSP /// Initialize GDT on the BSP
pub unsafe fn init(tcb_offset: usize) { pub unsafe fn init(tcb_offset: usize, stack_offset: usize) {
// Setup the initial GDT with TLS, so we can setup the TLS GDT (a little confusing) // Setup the initial GDT with TLS, so we can setup the TLS GDT (a little confusing)
// This means that each CPU will have its own GDT, but we only need to define it once as a thread local // This means that each CPU will have its own GDT, but we only need to define it once as a thread local
INIT_GDTR.limit = (INIT_GDT.len() * mem::size_of::<GdtEntry>() - 1) as u16; INIT_GDTR.limit = (INIT_GDT.len() * mem::size_of::<GdtEntry>() - 1) as u16;
@ -99,11 +99,11 @@ pub unsafe fn init(tcb_offset: usize) {
INIT_GDT[GDT_KERNEL_TLS].set_offset(tcb_offset as u32); INIT_GDT[GDT_KERNEL_TLS].set_offset(tcb_offset as u32);
// Run the AP GDT initialization, which does the rest // Run the AP GDT initialization, which does the rest
init_ap(tcb_offset); init_ap(tcb_offset, stack_offset);
} }
/// Initialize GDT for an AP /// Initialize GDT for an AP
pub unsafe fn init_ap(tcb_offset: usize) { pub unsafe fn init_ap(tcb_offset: usize, stack_offset: usize) {
// Load the initial GDT, before we have access to thread locals // Load the initial GDT, before we have access to thread locals
dtables::lgdt(&INIT_GDTR); dtables::lgdt(&INIT_GDTR);
@ -118,12 +118,16 @@ pub unsafe fn init_ap(tcb_offset: usize) {
GDTR.limit = (GDT.len() * mem::size_of::<GdtEntry>() - 1) as u16; GDTR.limit = (GDT.len() * mem::size_of::<GdtEntry>() - 1) as u16;
GDTR.base = GDT.as_ptr() as u64; GDTR.base = GDT.as_ptr() as u64;
// Set the TLS segment to the offset of the Thread Control Block
GDT[GDT_KERNEL_TLS].set_offset(tcb_offset as u32); GDT[GDT_KERNEL_TLS].set_offset(tcb_offset as u32);
// We can now access our TSS, which is a thread local // We can now access our TSS, which is a thread local
GDT[GDT_TSS].set_offset(&TSS as *const _ as u32); GDT[GDT_TSS].set_offset(&TSS as *const _ as u32);
GDT[GDT_TSS].set_limit(mem::size_of::<TaskStateSegment>() as u32); GDT[GDT_TSS].set_limit(mem::size_of::<TaskStateSegment>() as u32);
// Set the stack pointer when coming back from userspace
TSS.rsp[0] = stack_offset as u64;
// Load the new GDT, which is correctly located in thread local storage // Load the new GDT, which is correctly located in thread local storage
dtables::lgdt(&GDTR); dtables::lgdt(&GDTR);

4
arch/x86_64/src/start.rs
View file

@ -75,7 +75,7 @@ pub unsafe extern fn kstart() -> ! {
let mut active_table = paging::init(stack_start, stack_end); let mut active_table = paging::init(stack_start, stack_end);
// Set up GDT // Set up GDT
gdt::init((&__tbss_end as *const u8 as *const usize).offset(-1) as usize); gdt::init((&__tbss_end as *const u8 as *const usize).offset(-1) as usize, stack_end);
// Set up IDT // Set up IDT
idt::init(); idt::init();
@ -146,7 +146,7 @@ pub unsafe extern fn kstart_ap(stack_start: usize, stack_end: usize) -> ! {
let mut active_table = paging::init(stack_start, stack_end); let mut active_table = paging::init(stack_start, stack_end);
// Set up GDT for AP // Set up GDT for AP
gdt::init_ap((&__tbss_end as *const u8 as *const usize).offset(-1) as usize); gdt::init_ap((&__tbss_end as *const u8 as *const usize).offset(-1) as usize, stack_end);
// Set up IDT for AP // Set up IDT for AP
idt::init(); idt::init();