void gdt_init(void)
{
gdt_ptr.limit = (sizeof(uint64_t) * 3) - 1;
gdt_ptr.base = (uint32_t)&gdt_table;
gdt_set(0, 0, 0, 0, 0); /* Null segment */
gdt_set(1, 0, 0xFFFFFFFF, 0x9A, 0xCF); /* Code segment */
gdt_set(2, 0, 0xFFFFFFFF, 0x92, 0xCF); /* Data segment */
gdt_write((uint32_t)&gdt_ptr);
}
void init_gdt()
{
gdt_ptr.size = (sizeof(gdt_entry_t) * 6) - 1;
gdt_ptr.base = (u32int)&gdt_entries;
gdt_set(0, 0, 0, 0, 0); // Null segment
gdt_set(1, 0, 0xFFFFFFFF, 0x9A, 0xCF); // Code segment
gdt_set(2, 0, 0xFFFFFFFF, 0x92, 0xCF); // Data segment
gdt_set(3, 0, 0xFFFFFFFF, 0xFA, 0xCF); // User mode code segment
gdt_set(4, 0, 0xFFFFFFFF, 0xF2, 0xCF); // User mode data segment
write_tss(5, 0x10, 0x0);
gdt_flush((u32int)&gdt_ptr);
tss_flush();
}
void
gdt_initialize (void)
{
// Null Descriptor
set_gate (GDT_NLSEG / sizeof(gdt_entry_t), 0, 0, 0, 0);
// Kernel Code Segment
set_gate (GDT_KCSEG / sizeof(gdt_entry_t), 0, 0xFFFFFFFF, 0x9A, GDT_FLAGS);
// Kernel Data Segment
set_gate (GDT_KDSEG / sizeof(gdt_entry_t), 0, 0xFFFFFFFF, 0x92, GDT_FLAGS);
// User Code Segment
set_gate (GDT_UCSEG / sizeof(gdt_entry_t), 0, 0xFFFFFFFF, 0xFA, GDT_FLAGS);
// User Data Segment
set_gate (GDT_UDSEG / sizeof(gdt_entry_t), 0, 0xFFFFFFFF, 0xF2, GDT_FLAGS);
// TSS
// TODO.
gdt_ptr_t gdt_ptr;
gdt_ptr.limit = sizeof(gdt_entry_t) * GDT_NUM_ENTRIES - 1;
gdt_ptr.base = (uintptr_t) &gdt_entries;
gdt_set ((uintptr_t) &gdt_ptr);
}
/* Set up and install our three segments */
void gdt_install()
{
gp.limit = (sizeof(struct gdt_entry) * 3) - 1;
gp.base = (unsigned long)&gdt;
gdt_set_entry(0, 0, 0, 0, 0);
gdt_set_entry(1, 0, 0xFFFFFFFF, 0x9A, 0xCF);
gdt_set_entry(2, 0, 0xFFFFFFFF, 0x92, 0xCF);
gdt_set();
}
void gdt_init()
{
//Setup the GDT pointer and limit
gdt_pointer.limit = (sizeof(struct gdt_entry) * GDT_ENTRY_COUNT) - 1;
gdt_pointer.base = (unsigned int)&gdt_table;
//NULL descriptor
gdt_set(0, 0, 0, 0, 0);
//Code segment
gdt_set(1, 0, 0xFFFFFFFF, 0x9A, 0xCF);
//Data Segment
gdt_set(2, 0, 0xFFFFFFFF, 0x92, 0xCF);
gdt_set(3, (unsigned int)&sys_task_state, (unsigned int)&sys_task_state + sizeof(sys_task_state) + 1, 0x89, 0x40);
//Load the new GDT
gdt_load();
}
void gdt_init() {
gdt_set_entry(0, 0, 0, 0);
gdt_set_entry(1, 0, 0xFFFFFFFF, 0x9A);
gdt_set_entry(2, 0, 0xFFFFFFFF, 0x92);
gdt_set_entry(3, 0, 0xFFFFFFFF, 0xFA);
gdt_set_entry(4, 0, 0xFFFFFFFF, 0xF2);
ptr.base = (uint32_t) &gdt_tab;
ptr.limit = (sizeof(struct gdt_info) * GDT_LEN) - 1;
gdt_set(&ptr);
}
static void write_tss(u32int idx, u32int ss0, u32int esp0)
{
u32int base = (u32int)&tss_entry;
u32int limit = base + sizeof(tss_entry_t);
gdt_set(idx, base, limit, 0xE9, 0x00);
memset(&tss_entry, 0, sizeof(tss_entry_t));
tss_entry.ss0 = ss0;
tss_entry.esp0 = esp0;
tss_entry.cs = 0x0b;
tss_entry.ss = tss_entry.ds = tss_entry.es = tss_entry.fs = tss_entry.gs = 0x13;
}
