118 lines
3.7 KiB
C
118 lines
3.7 KiB
C
#include <kernel/kernel.h>
|
|
#include <kernel/multiboot.h>
|
|
#include <kernel/mem.h>
|
|
#include <kernel/serial.h>
|
|
#include <kernel/idt.h>
|
|
#include <kernel/pic.h>
|
|
#include <kernel/pit.h>
|
|
#include <stdint.h>
|
|
|
|
kernel_ctx_t ctx = {0};
|
|
struct idt_entry idt[256] = {0};
|
|
struct idtr idtr = {0};
|
|
tss_t tss = {0};
|
|
|
|
extern uint32_t isr_stub_table[32];
|
|
extern void pit_isr(void);
|
|
extern void jmp_user_mode(uint32_t esp, uint32_t eip);
|
|
extern void flush_tss(uint32_t segment_selector);
|
|
extern gdt_t gdt[6];
|
|
extern void enable_paging(uint32_t *page_directory);
|
|
|
|
void exception_handler(int_stack_frame_t r) {
|
|
LOG("Exception 0x%X (0x%X) has occurred\nEAX: 0x%08X\nECX: 0x%08X\nEDX: 0x%08X\nEBX: 0x%08X\nESI: 0x%08X\nEDI: 0x%08X\nEBP: 0x%08X\nESP: 0x%08X\n",
|
|
r.int_no, r.err_code, r.eax, r.ecx, r.edx, r.ebx, r.esi, r.edi, r.ebp, r.esp+24);
|
|
LOG("\nEIP: 0x%08X\nCS: 0x%08X\nEFLAGS: 0x%08X\n",
|
|
r.eip, r.cs, r.eflags);
|
|
}
|
|
|
|
void sleep(int delay) {
|
|
uint64_t end = ctx.ticks + delay;
|
|
while (ctx.ticks < end)
|
|
cpu_relax;
|
|
}
|
|
|
|
typedef struct {
|
|
uint32_t eip;
|
|
uint32_t esp;
|
|
uint32_t cr3;
|
|
} task_t;
|
|
|
|
__attribute__((aligned(4096))) uint32_t page_dir[1024];
|
|
__attribute__((aligned(4096))) uint32_t page_tab[1024];
|
|
|
|
void kernel(multiboot_info_t *info) {
|
|
if (!CHECK_FLAG(info->flags, 3)) goto halt; // Modules
|
|
if (!CHECK_FLAG(info->flags, 6)) goto halt; // Memory map
|
|
if (!CHECK_FLAG(info->flags, 12)) goto halt; // VBE data
|
|
ctx.multi_mmap = (multi_mmap_t *)info->memmapaddress;
|
|
ctx.multi_mmap_size = info->memmaplength;
|
|
|
|
if (serial_port_init(COM1)) ctx.log_method = LOG_COM1;
|
|
LOG("Kernel log being sent to COM1\n");
|
|
|
|
if (!mmap_init()) goto halt;
|
|
LOG("%d bytes of RAM detected\nCreated a %d byte large physical memory map at 0x%08X\n", ctx.mmap_size*BLOCK_SIZE*8, ctx.mmap_size, (uint32_t)ctx.mmap);
|
|
|
|
for (int i = 0; i < 32; i++) {
|
|
idt_encode_entry(idt, i, isr_stub_table[i], GDT_SEGMENT_SELECTOR(1, 0), TRAP_GATE_32 | INT_RING0 | INT_PRESENT);
|
|
}
|
|
idt_encode_entry(idt, 32, (uint32_t)pit_isr, GDT_SEGMENT_SELECTOR(1, 0), INT_GATE_32 | INT_RING0 | INT_PRESENT);
|
|
|
|
idtr.size = (sizeof(struct idt_entry) * 256) - 1;
|
|
idtr.base = (uint32_t) idt;
|
|
|
|
asm volatile ("lidt %0" :: "m"(idtr));
|
|
pic_remap(PIC_1_START, PIC_2_START);
|
|
/*
|
|
asm volatile ("sti" ::);
|
|
|
|
ctx.ticks = 0;
|
|
pit_init();
|
|
|
|
uint32_t base = (uint32_t)&tss;
|
|
uint32_t limit = base + sizeof(tss_t);
|
|
gdt[5].base_low = base & 0xFFFF;
|
|
gdt[5].base_middle = (base >> 16) & 0xFF;
|
|
gdt[5].base_high = (base >> 24) & 0xFF;
|
|
gdt[5].limit_low = limit & 0xFFFF;
|
|
gdt[5].granularity = (limit >> 16) & 0x0F;
|
|
gdt[5].granularity |= 0x40;
|
|
gdt[5].access = 0x89;
|
|
tss.ss0 = GDT_SEGMENT_SELECTOR(2, RING0);
|
|
tss.esp0 = 0;
|
|
tss.cs = GDT_SEGMENT_SELECTOR(3, RING3);
|
|
tss.ss = tss.ds = tss.es = tss.fs = tss.gs = GDT_SEGMENT_SELECTOR(4, RING3);
|
|
flush_tss(GDT_SEGMENT_SELECTOR(5, RING3));
|
|
*/
|
|
|
|
#define PAGE_PRESENT (1<<0)
|
|
#define PAGE_RW (1<<1)
|
|
#define PAGE_USER (1<<2)
|
|
|
|
#define PAGE_DIR_INDEX(x) (((x) >> 22) & 0x3FF)
|
|
#define PAGE_TAB_INDEX(x) (((x) >> 12) & 0x3FF)
|
|
#define PAGE_OFFSET(x) ((x) & 0xFFF)
|
|
|
|
LOG("Page directory: %08X -- Page table: %08X\n", page_dir, page_tab);
|
|
|
|
for (int i = 0; i < 1024; i++) {
|
|
page_tab[i] = (i * 0x1000) | PAGE_PRESENT | PAGE_RW | PAGE_USER;
|
|
}
|
|
|
|
for (int i = 0; i < 1024; i++) {
|
|
page_dir[i] = ((uint32_t)page_tab) | PAGE_PRESENT | PAGE_RW | PAGE_USER;
|
|
}
|
|
|
|
enable_paging(page_dir);
|
|
|
|
uint32_t stack = (uint32_t)mmap_find_first_free_block();
|
|
multi_mod_t *init = (multi_mod_t *)info->moduleaddress;
|
|
LOG("Switching to ring 3... EIP: 0x%08X ESP: 0x%08X\n", init->mod_start, stack+0x1000);
|
|
|
|
jmp_user_mode(stack+0x1000, init->mod_start);
|
|
|
|
halt:
|
|
for (;;) {}
|
|
}
|