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kernel/arch/protected.c
Braiden Vasco 237148dd51 Remap the IRQ table, enable interrupts
2017-11-03 04:09:45 +00:00

174 lines
6.2 KiB
C
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#include "protected.h"
#include "config.h"
#include "logger.h"
#include "asm.h"
#include "exception.h"
#include "hwint.h"
struct GdtPointer {
unsigned short limit;
unsigned int base;
}
__attribute__((packed));
struct IdtPointer {
unsigned short limit;
unsigned int base;
}
__attribute__((packed));
struct GdtEntry {
unsigned short limit_low;
unsigned short base_low;
unsigned char base_middle;
unsigned char access;
unsigned char granularity;
unsigned char base_high;
}
__attribute__((packed));
struct IdtEntry {
unsigned short base_lo;
unsigned short sel;
unsigned char always0;
unsigned char flags;
unsigned short base_hi;
}
__attribute__((packed));
static struct GdtPointer gdt_pointer;
static struct IdtPointer idt_pointer;
static struct GdtEntry gdt_entries[GDT_SIZE];
static struct IdtEntry idt_entries[IDT_SIZE];
static void gdt_set_gate(int num, unsigned int base, unsigned int limit, unsigned char access, unsigned char gran);
static void idt_set_gate(unsigned char num, unsigned int base, unsigned short sel, unsigned char flags);
void gdt_flush(const struct GdtPointer *pointer);
void idt_flush(const struct IdtPointer *pointer);
void protected_initialize()
{
logger_info("Remap the IRQ table.");
outportb(0x20, 0x11);
outportb(0xA0, 0x11);
outportb(0x21, 0x20);
outportb(0xA1, 0x28);
outportb(0x21, 0x04);
outportb(0xA1, 0x02);
outportb(0x21, 0x01);
outportb(0xA1, 0x01);
outportb(0x21, 0x00);
outportb(0xA1, 0x00);
logger_info("Setup GDT.");
gdt_set_gate(GDT_NULL_INDEX, 0, 0x00000000, 0, 0);
gdt_set_gate(GDT_KERNEL_CS_INDEX, 0, 0xFFFFFFFF, 0x9A, 0xCF);
gdt_set_gate(GDT_KERNEL_DS_INDEX, 0, 0xFFFFFFFF, 0x92, 0xCF);
gdt_set_gate(GDT_USER_CS_INDEX, 0, 0xFFFFFFFF, 0xFA, 0xCF);
gdt_set_gate(GDT_USER_DS_INDEX, 0, 0xFFFFFFFF, 0xF2, 0xCF);
logger_info("Setup IDT.");
for (unsigned char *p = (unsigned char*)idt_entries; p < (unsigned char*)&idt_entries[IDT_SIZE]; ++p) {
*p = 0;
}
idt_set_gate(0, (unsigned int)exception_0, 0x08, 0x8E);
idt_set_gate(1, (unsigned int)exception_1, 0x08, 0x8E);
idt_set_gate(2, (unsigned int)exception_2, 0x08, 0x8E);
idt_set_gate(3, (unsigned int)exception_3, 0x08, 0x8E);
idt_set_gate(4, (unsigned int)exception_4, 0x08, 0x8E);
idt_set_gate(5, (unsigned int)exception_5, 0x08, 0x8E);
idt_set_gate(6, (unsigned int)exception_6, 0x08, 0x8E);
idt_set_gate(7, (unsigned int)exception_7, 0x08, 0x8E);
idt_set_gate(8, (unsigned int)exception_8, 0x08, 0x8E);
idt_set_gate(9, (unsigned int)exception_9, 0x08, 0x8E);
idt_set_gate(10, (unsigned int)exception_10, 0x08, 0x8E);
idt_set_gate(11, (unsigned int)exception_11, 0x08, 0x8E);
idt_set_gate(12, (unsigned int)exception_12, 0x08, 0x8E);
idt_set_gate(13, (unsigned int)exception_13, 0x08, 0x8E);
idt_set_gate(14, (unsigned int)exception_14, 0x08, 0x8E);
idt_set_gate(15, (unsigned int)exception_15, 0x08, 0x8E);
idt_set_gate(16, (unsigned int)exception_16, 0x08, 0x8E);
idt_set_gate(17, (unsigned int)exception_17, 0x08, 0x8E);
idt_set_gate(18, (unsigned int)exception_18, 0x08, 0x8E);
idt_set_gate(19, (unsigned int)exception_19, 0x08, 0x8E);
idt_set_gate(20, (unsigned int)exception_20, 0x08, 0x8E);
idt_set_gate(21, (unsigned int)exception_21, 0x08, 0x8E);
idt_set_gate(22, (unsigned int)exception_22, 0x08, 0x8E);
idt_set_gate(23, (unsigned int)exception_23, 0x08, 0x8E);
idt_set_gate(24, (unsigned int)exception_24, 0x08, 0x8E);
idt_set_gate(25, (unsigned int)exception_25, 0x08, 0x8E);
idt_set_gate(26, (unsigned int)exception_26, 0x08, 0x8E);
idt_set_gate(27, (unsigned int)exception_27, 0x08, 0x8E);
idt_set_gate(28, (unsigned int)exception_28, 0x08, 0x8E);
idt_set_gate(29, (unsigned int)exception_29, 0x08, 0x8E);
idt_set_gate(30, (unsigned int)exception_30, 0x08, 0x8E);
idt_set_gate(31, (unsigned int)exception_31, 0x08, 0x8E);
idt_set_gate(32, (unsigned int)hwint_0, 0x08, 0x8E);
idt_set_gate(33, (unsigned int)hwint_1, 0x08, 0x8E);
idt_set_gate(34, (unsigned int)hwint_2, 0x08, 0x8E);
idt_set_gate(35, (unsigned int)hwint_3, 0x08, 0x8E);
idt_set_gate(36, (unsigned int)hwint_4, 0x08, 0x8E);
idt_set_gate(37, (unsigned int)hwint_5, 0x08, 0x8E);
idt_set_gate(38, (unsigned int)hwint_6, 0x08, 0x8E);
idt_set_gate(39, (unsigned int)hwint_7, 0x08, 0x8E);
idt_set_gate(40, (unsigned int)hwint_8, 0x08, 0x8E);
idt_set_gate(41, (unsigned int)hwint_9, 0x08, 0x8E);
idt_set_gate(42, (unsigned int)hwint_10, 0x08, 0x8E);
idt_set_gate(43, (unsigned int)hwint_11, 0x08, 0x8E);
idt_set_gate(44, (unsigned int)hwint_12, 0x08, 0x8E);
idt_set_gate(45, (unsigned int)hwint_13, 0x08, 0x8E);
idt_set_gate(46, (unsigned int)hwint_14, 0x08, 0x8E);
idt_set_gate(47, (unsigned int)hwint_15, 0x08, 0x8E);
logger_info("Load GDT.");
gdt_pointer.limit = sizeof(struct GdtEntry) * GDT_SIZE - 1;
gdt_pointer.base = (unsigned int)&gdt_entries;
gdt_flush(&gdt_pointer);
logger_info("Load IDT.");
idt_pointer.limit = sizeof(struct IdtEntry) * IDT_SIZE - 1;
idt_pointer.base = (unsigned int)&idt_entries;
idt_flush(&idt_pointer);
logger_info("Enable interrupts.");
asm volatile ("sti");
}
void gdt_set_gate(int num, unsigned int base, unsigned int limit, unsigned char access, unsigned char gran)
{
gdt_entries[num].base_low = (base & 0xFFFF);
gdt_entries[num].base_middle = (base >> 16) & 0xFF;
gdt_entries[num].base_high = (base >> 24) & 0xFF;
gdt_entries[num].limit_low = (limit & 0xFFFF);
gdt_entries[num].granularity = (limit >> 16) & 0x0F;
gdt_entries[num].granularity |= gran & 0xF0;
gdt_entries[num].access = access;
}
void idt_set_gate(unsigned char num, unsigned int base, unsigned short sel, unsigned char flags)
{
idt_entries[num].base_lo = base & 0xFFFF;
idt_entries[num].base_hi = (base >> 16) & 0xFFFF;
idt_entries[num].sel = sel;
idt_entries[num].always0 = 0;
// We must uncomment the OR below when we get to using user-mode.
// It sets the interrupt gate's privilege level to 3.
idt_entries[num].flags = flags /* | 0x60 */;
}
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