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0fa405dd98
luciaos/kernel.c
Lucia Ceionia 0fa405dd98 real initial commit
2022-09-14 16:50:44 -05:00

454 lines
14 KiB
C
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#include <stdint.h>
typedef unsigned short word;
char nibbleToHex(char n) {
return n > 9 ? (n - 10) + 'A' : n + '0';
}
void printByte(char v, short *buff) {
*(char *)&buff[0] = nibbleToHex((v >> 4) & 0xF);
*(char *)&buff[1] = nibbleToHex(v & 0xF);
}
void printWord(short v, short *buff) {
printByte(v >> 8, buff);
printByte(v, &buff[2]);
}
void printDword(int v, short *buff) {
printWord(v >> 16, buff);
printWord(v, &buff[4]);
}
char check_apic() {
uint32_t eax, ebx, ecx, edx;
asm("cpuid" : "=a"(eax), "=b"(ebx), "=c"(ecx), "=d"(edx) : "a"(1));
return (edx & (1 << 9)) != 0;
}
char check_sse() {
uint32_t eax, ebx, ecx, edx;
asm("cpuid" : "=a"(eax), "=b"(ebx), "=c"(ecx), "=d"(edx) : "a"(1));
return (edx & (1 << 25)) != 0;
}
struct __attribute__((__packed__)) IDTR_t {
uint16_t size;
uint32_t offset;
};
struct __attribute__((__packed__)) InterruptDescriptor32 {
uint16_t offset_1; // offset bits 0..15
uint16_t selector; // a code segment selector in GDT or LDT
uint8_t zero; // unused, set to 0
uint8_t type_attributes; // gate type, dpl, and p fields
uint16_t offset_2; // offset bits 16..31
};
__attribute__((aligned(0x10)))
struct InterruptDescriptor32 IDT[256];
struct IDTR_t IDTR;
void outb(uint16_t port, uint8_t value) {
asm volatile("outb %%al, %%dx" : : "d"(port), "a"(value));
}
uint8_t inb(uint16_t port) {
uint8_t value;
asm volatile("inb %%dx, %%al" : "=a"(value) : "d"(port));
return value;
}
void IRQ_set_mask(char IRQline) {
uint16_t port;
uint8_t value;
if (IRQline < 8) {
port = 0x21;
} else {
port = 0xA1;
IRQline -= 8;
}
value = inb(port) | (1 << IRQline);
outb(port, value);
}
void IRQ_clear_mask(char IRQline) {
uint16_t port;
uint8_t value;
if (IRQline < 8) {
port = 0x21;
} else {
port = 0xA1;
IRQline -= 8;
}
value = inb(port) & ~(1 << IRQline);
outb(port, value);
}
struct interrupt_frame {
uint32_t eip, cs;
uint32_t eflags;
uint32_t esp, ss;
uint32_t es, ds, fs, gs;
};
/* Real Mode helper macros */
/* segment:offset pair */
typedef uint32_t FARPTR;
/* Make a FARPTR from a segment and an offset */
#define MK_FP(seg, off) ((FARPTR) (((uint32_t) (seg) << 16) | (uint16_t) (off)))
/* Extract the segment part of a FARPTR */
#define FP_SEG(fp) (((FARPTR) fp) >> 16)
/* Extract the offset part of a FARPTR */
#define FP_OFF(fp) (((FARPTR) fp) & 0xffff)
/* Convert a segment:offset pair to a linear address */
#define FP_TO_LINEAR(seg, off) ((void*)(uintptr_t)((((uint32_t)seg) << 4) + ((uint32_t)off)))
FARPTR i386LinearToFp(void *ptr)
{
unsigned seg, off;
off = (uintptr_t) ptr & 0xffff;
seg = ((uintptr_t) ptr >> 16);
return MK_FP(seg, off);
}
#define EFLAG_IF ((uint32_t)1 << 9)
#define EFLAG_VM ((uint32_t)1 << 17)
char v86_if = 0;
extern void real_test();
extern void kbd_wait();
#define VALID_FLAGS 0xDFF
__attribute__ ((interrupt))
void gpf_handler_v86(struct interrupt_frame *frame, uint32_t error_code) {
asm volatile("mov %%ax,%%ds"::"a"(0x10));
uint8_t *ip;
uint16_t *stack, *ivt;
uint32_t *stack32;
char is_operand32 = 0, is_address32 = 0;
ip = ((frame->cs << 4) + frame->eip) & 0xFFFFF;
ivt = (uint16_t*)0x0000;
stack = FP_TO_LINEAR(frame->ss, frame->esp);
stack32 = (uint32_t*)stack;
char *vga = (char*)0xb8000 + (160 * 10);
vga[0] = 'I'; vga[2] = 'P'; printWord(frame->eip, &vga[4]); vga += 14;
vga[0] = 'C'; vga[2] = 'S'; printWord(frame->cs, &vga[4]); vga += 14;
vga[0] = 'F'; vga[2] = 'L'; printDword(frame->eflags, &vga[4]); vga += 14;
vga = (char*)0xb8000 + (160 * 11);
vga[0] = 'S'; vga[2] = 'P'; printWord(frame->esp, &vga[4]); vga += 14;
vga[0] = 'S'; vga[2] = 'S'; printWord(frame->ss, &vga[4]); vga += 14;
vga = (char*)0xb8000 + (160 * 12);
vga[0] = 'E'; vga[2] = 'S'; printWord(frame->es, &vga[4]); vga += 14;
vga[0] = 'D'; vga[2] = 'S'; printWord(frame->ds, &vga[4]); vga += 14;
vga[0] = 'F'; vga[2] = 'S'; printWord(frame->fs, &vga[4]); vga += 14;
vga[0] = 'G'; vga[2] = 'S'; printWord(frame->gs, &vga[4]); vga += 14;
//vga[2]++;
//printDword(frame, &vga[20]);
//vga = &vga[38];
//uint32_t *fr = frame;
//for (int i = 0; i < sizeof(struct interrupt_frame)/sizeof(uint32_t); i++) {
// printDword(fr[i], vga);
// vga += (sizeof(uint32_t)*2+1)*2;
//}
//vga = (char*)0xb80A0;
//printDword(ip, &vga[20]);
//vga = &vga[38];
//for (int i = 0; i < 16; i++) {
// printByte(ip[i], vga);
// vga += (sizeof(uint8_t)*2)*2;
//}
vga = (char*)0xb8000 + (160*3);
for(;;) {
switch (ip[0]) {
case 0x66: // O32
is_operand32 = 1;
ip++;
frame->eip = (uint16_t)(frame->eip + 1);
break;
case 0x67: // A32
is_address32 = 1;
ip++;
frame->eip = (uint16_t)(frame->eip + 1);
break;
case 0x9C: // PUSHF
if (is_operand32) {
frame->esp = ((frame->esp & 0xffff) - 4) & 0xffff;
stack32--;
stack32[0] = frame->eflags & VALID_FLAGS;
if (v86_if)
stack32[0] |= EFLAG_IF;
else
stack32[0] &= ~EFLAG_IF;
} else {
frame->esp = ((frame->esp & 0xffff) - 2) & 0xffff;
stack--;
stack[0] = (uint16_t)frame->eflags;
if (v86_if)
stack[0] |= EFLAG_IF;
else
stack[0] &= ~EFLAG_IF;
}
frame->eip = (uint16_t)(frame->eip + 1);
goto done;
case 0x9D: // POPF
if (is_operand32) {
frame->eflags = EFLAG_IF | EFLAG_VM | (stack32[0] & VALID_FLAGS);
v86_if = (stack32[0] & EFLAG_IF) != 0;
frame->esp = ((frame->esp & 0xffff) + 4) & 0xffff;
} else {
frame->eflags = EFLAG_IF | EFLAG_VM | stack[0];
v86_if = (stack[0] & EFLAG_IF) != 0;
frame->esp = ((frame->esp & 0xffff) + 2) & 0xffff;
}
frame->eip = (uint16_t)(frame->eip + 1);
goto done;
case 0xCD: // INT n
vga[0] = 'I'; vga[2]++; if (vga[2] < '0') vga[2] = '0';
asm volatile("nop\nnop");
switch (ip[1]) {
case 0x30: // Exit V86 Mode?
asm volatile("nop\nnop");
asm volatile("jmp jmp_usermode_test");
//__builtin_unreachable();
break;
//case 0x20: // ???
//case 0x21: // ???
case 0x3: // Debugger trap
kbd_wait();
asm volatile("nop");
default:
stack -= 3;
frame->esp = ((frame->esp & 0xffff) - 6) & 0xffff;
stack[0] = (uint16_t) (frame->eip + 2);
stack[1] = frame->cs;
stack[2] = (uint16_t) frame->eflags;
if (v86_if)
stack[2] |= EFLAG_IF;
else
stack[2] &= ~EFLAG_IF;
frame->cs = ivt[ip[1] * 2 + 1];
frame->eip = ivt[ip[1] * 2];
asm volatile("nop");
//frame->cs = 0;
//frame->eip = real_test;
goto done;
}
goto done;
case 0xCF: // IRET
frame->eip = stack[0];
frame->cs = stack[1];
frame->eflags = EFLAG_IF | EFLAG_VM | stack[2];
v86_if = (stack[2] & EFLAG_IF) != 0;
frame->esp = ((frame->esp & 0xffff) + 6) & 0xffff;
goto done;
case 0xFA: // CLI
v86_if = 0;
frame->eip = (uint16_t) (frame->eip + 1);
goto done;
case 0xFB: // STI
v86_if = 1;
frame->eip = (uint16_t) (frame->eip + 1);
goto done;
default:
goto done;
}
}
done:
vga = (char*)0xb8000 + (160 * 13);
vga[0] = 'I'; vga[2] = 'P'; printWord(frame->eip, &vga[4]); vga += 14;
vga[0] = 'C'; vga[2] = 'S'; printWord(frame->cs, &vga[4]); vga += 14;
vga[0] = 'F'; vga[2] = 'L'; printDword(frame->eflags, &vga[4]); vga += 14;
vga = (char*)0xb8000 + (160 * 14);
vga[0] = 'S'; vga[2] = 'P'; printWord(frame->esp, &vga[4]); vga += 14;
vga[0] = 'S'; vga[2] = 'S'; printWord(frame->ss, &vga[4]); vga += 14;
vga = (char*)0xb8000 + (160 * 15);
vga[0] = 'E'; vga[2] = 'S'; printWord(frame->es, &vga[4]); vga += 14;
vga[0] = 'D'; vga[2] = 'S'; printWord(frame->ds, &vga[4]); vga += 14;
vga[0] = 'F'; vga[2] = 'S'; printWord(frame->fs, &vga[4]); vga += 14;
vga[0] = 'G'; vga[2] = 'S'; printWord(frame->gs, &vga[4]); vga += 14;
}
extern void timerHandler();
extern void keyboardHandler();
extern void gpfHandler();
extern void unhandled_handler();
extern void picInit();
void set_system_gate(uint8_t gate, void (*handler)()) {
IDT[gate].offset_1 = (uint32_t)handler & 0xFFFF;
IDT[gate].offset_2 = ((uint32_t)handler >> 16) & 0xFFFF;
IDT[gate].selector = 0x08;
IDT[gate].type_attributes = 0x8E;
}
void set_trap_gate(uint8_t gate, void (*handler)()) {
IDT[gate].offset_1 = (uint32_t)handler & 0xFFFF;
IDT[gate].offset_2 = ((uint32_t)handler >> 16) & 0xFFFF;
IDT[gate].selector = 0x08;
IDT[gate].type_attributes = 0x8F;
}
void setup_interrupts() {
IDTR.size = 256*8 - 1;
IDTR.offset = (uint32_t)IDT;
for (int i = 0; i < 256; i++) {
*(uint64_t*)&IDT[i] = 0;
}
for (int i = 0; i < 9; i++) {
set_trap_gate(i, unhandled_handler);
}
for (int i = 10; i < 15; i++) {
set_trap_gate(i, unhandled_handler);
}
for (int i = 16; i < 22; i++) {
set_trap_gate(i, unhandled_handler);
}
set_system_gate(0x20, timerHandler);
set_system_gate(0x21, keyboardHandler);
set_trap_gate(13, gpf_handler_v86);
//set_trap_gate(13, gpfHandler);
asm volatile("lidt %0": : "m"(IDTR));
picInit();
IRQ_clear_mask(0);
IRQ_clear_mask(1);
asm volatile("sti");
}
struct __attribute__((__packed__)) tss_entry_struct {
uint32_t prev_tss;
uint32_t esp0;
uint32_t ss0;
uint32_t esp1;
uint32_t ss1;
uint32_t esp2;
uint32_t ss2;
uint32_t cr3;
uint32_t eip;
uint32_t eflags;
uint32_t eax;
uint32_t ecx;
uint32_t edx;
uint32_t ebx;
uint32_t esp;
uint32_t ebp;
uint32_t esi;
uint32_t edi;
uint32_t es;
uint32_t cs;
uint32_t ss;
uint32_t ds;
uint32_t fs;
uint32_t gs;
uint32_t ldt;
uint32_t trap;
uint32_t iomap_base;
};
struct tss_entry_struct *tss_data;
void write_tss() {
tss_data = (struct tss_entry_struct *)0x20000;
for (int i = 0; i < 0x2080; i++)
((uint8_t*)tss_data)[i] = 0;
tss_data->ss0 = 0x10;
tss_data->esp0 = 0x400000;
tss_data->iomap_base = 0x80;
}
void enable_sse() {
asm volatile(
"mov %%cr0, %%eax\n"
"and $0xFFFB, %%ax\n"
"or $0x2, %%ax\n"
"mov %%eax, %%cr0\n"
"mov %%cr4, %%eax\n"
"or $0x600, %%ax\n"
"mov %%eax, %%cr4\n"
: : : "%eax"
);
}
void print_flags() {
uint32_t flags;
asm volatile("pushfd\npop %%eax":"=a"(flags));
printDword(flags, 0xB8000 + (160*4) + 50);
}
void print_cr0() {
uint32_t reg;
asm volatile("mov %%cr0, %%eax":"=a"(reg));
printDword(reg, 0xB8000 + (160*5) + 50);
}
void print_cr3() {
uint32_t reg;
asm volatile("mov %%cr3, %%eax":"=a"(reg));
printDword(reg, 0xB8000 + (160*5) + 50 + 8*2 + 2);
}
void print_cr4() {
uint32_t reg;
asm volatile("mov %%cr4, %%eax":"=a"(reg));
printDword(reg, 0xB8000 + (160*5) + 50 + 8*4 + 4);
}
extern void enter_v86(uint32_t ss, uint32_t esp, uint32_t cs, uint32_t eip);
extern void v86Code();
extern void flushTSS();
extern void jmp_usermode_test();
/*
Real Mode Accessible (First MB)
00000 - 02000 IVT
01000 - 04000 Paging
04000 - 07C00 Free
07C00 - 08000 Boot
08000 - 20000 Kernel Code
20000 - 22080 TSS
80000 - 90000 Real Mode Stack
90000 - A0000 Free
A0000 - FFFFF BIOS Area
Protected Only (1MB+)
100000 - Free
*/
void start() {
word *vga_text = (word *)0xb8000;
char h[] = "LuciaOS";
for (int i = 0; i < sizeof(h); i++)
*(char *)&vga_text[i] = h[i];
uint32_t o;
asm("mov %%esp, %%eax" : "=a"(o) : :);
printDword(o, (short *)&vga_text[80]);
asm("mov %%ebp, %%eax" : "=a"(o) : :);
printDword(o, (short *)&vga_text[160]);
//char c[] = "APIC support: ";
//char apic;
//printByte(apic = check_apic(), (short*)&vga_text[80*3 + sizeof(c) - 1]);
//for (int i = 0; i < sizeof(c); i++)
// *(char *)&vga_text[i+(80*3)] = c[i];
//if (!apic) return;
char sse_str[] = "SSE support: ";
char sse;
printByte(sse = check_sse(), (short*)&vga_text[80*4 + sizeof(sse_str) - 1]);
for (int i = 0; i < sizeof(sse_str); i++)
*(char *)&vga_text[i+(80*4)] = sse_str[i];
if (!sse) return;
enable_sse();
setup_interrupts();
write_tss();
flushTSS();
print_flags();
print_cr0();
print_cr3();
print_cr4();
FARPTR v86_entry = i386LinearToFp(v86Code);
enter_v86(0x8000, 0xFF00, FP_SEG(v86_entry), FP_OFF(v86_entry));
//jmp_usermode_test();
}
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