/** Set up the TSS for the current CPU.
* @param cpu CPU to initialize for. */
static __init_text void tss_init(cpu_t *cpu) {
/* Set up the contents of the TSS. Point the first IST entry at the
* double fault stack. */
memset(&cpu->arch.tss, 0, sizeof(cpu->arch.tss));
cpu->arch.tss.ist1 = (ptr_t)cpu->arch.double_fault_stack + KSTACK_SIZE;
cpu->arch.tss.io_bitmap = 104;
/* Load the TSS segment into TR. */
x86_ltr(KERNEL_TSS);
}
void x86_initialize_percpu_tss(void) {
struct x86_percpu* percpu = x86_get_percpu();
uint cpu_num = percpu->cpu_num;
tss_t* tss = &percpu->default_tss;
memset(tss, 0, sizeof(*tss));
/* zeroed out TSS is okay for now */
set_global_desc_64(TSS_SELECTOR(cpu_num), (uintptr_t)tss, sizeof(*tss) - 1, 1, 0, 0, SEG_TYPE_TSS, 0, 0);
x86_tss_assign_ists(percpu, tss);
tss->iomap_base = offsetof(tss_64_t, tss_bitmap);
// Need to have an extra byte at the end of the bitmap because it will always potentially read two bytes
tss->tss_bitmap[IO_BITMAP_BYTES] = 0xff;
x86_ltr(TSS_SELECTOR(cpu_num));
}
void arch_early_init(void)
{
x86_mmu_init();
platform_init_mmu_mappings();
/* enable caches here for now */
clear_in_cr0(X86_CR0_NW | X86_CR0_CD);
memset(&system_tss, 0, sizeof(tss_t));
system_tss.esp0 = 0;
system_tss.ss0 = DATA_SELECTOR;
system_tss.ss1 = 0;
system_tss.ss2 = 0;
system_tss.eflags = 0x00003002;
system_tss.bitmap = offsetof(tss_t, tss_bitmap);
system_tss.trace = 1; // trap on hardware task switch
set_global_desc(TSS_SELECTOR, &system_tss, sizeof(tss_t), 1, 0, 0, SEG_TYPE_TSS, 0, 0);
x86_ltr(TSS_SELECTOR);
}
