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#include <idt.h>
#include <gdt.h>
#include <sys.h>
#include <string.h>
#include <dbglog.h>
struct idt_entry {
uint16_t base_lo; //Low part of address to jump to
uint16_t sel; //Kernel segment selector
uint8_t always0;
uint8_t type_attr; //Type
uint16_t base_hi; //High part of address to jump to
} __attribute__((packed));
typedef struct idt_entry idt_entry_t;
struct idt_ptr {
uint16_t limit;
uint32_t base;
} __attribute__((packed));
typedef struct idt_ptr idt_ptr_t;
#define GATE_TYPE_INTERRUPT 14 // IF is cleared on interrupt
#define GATE_TYPE_TRAP 15 // IF stays as is
#define GATE_PRESENT (1<<7)
#define GATE_DPL_SHIFT 5
void isr0();
void isr1();
void isr2();
void isr3();
void isr4();
void isr5();
void isr6();
void isr7();
void isr8();
void isr9();
void isr10();
void isr11();
void isr12();
void isr13();
void isr14();
void isr15();
void isr16();
void isr17();
void isr18();
void isr19();
void isr20();
void isr21();
void isr22();
void isr23();
void isr24();
void isr25();
void isr26();
void isr27();
void isr28();
void isr29();
void isr30();
void isr31();
void irq0();
void irq1();
void irq2();
void irq3();
void irq4();
void irq5();
void irq6();
void irq7();
void irq8();
void irq9();
void irq10();
void irq11();
void irq12();
void irq13();
void irq14();
void irq15();
void syscall64();
// ************************************************************
// Handler code
static idt_entry_t idt_entries[256];
static idt_ptr_t idt_ptr;
static isr_handler_t irq_handlers[16] = {0};
static isr_handler_t ex_handlers[32] = {0};
/* Called in interrupt.s when an exception fires (interrupt 0 to 31) */
void idt_exHandler(registers_t *regs) {
if (ex_handlers[regs->int_no] != 0) {
ex_handlers[regs->int_no](regs);
} else {
//TODO: make sure all exceptions happenning in userspace do not cause kernel panic...
dbg_printf("Unhandled exception: %i\n", regs->int_no);
dbg_dump_registers(regs);
PANIC("Unhandled exception");
}
}
/* Called in interrupt.s when an IRQ fires (interrupt 32 to 47) */
void idt_irqHandler(registers_t *regs) {
if (regs->err_code > 7) {
outb(0xA0, 0x20);
}
outb(0x20, 0x20);
if (irq_handlers[regs->err_code] != 0) {
irq_handlers[regs->err_code](regs);
}
}
/* Caled in interrupt.s when a syscall is called */
void idt_syscallHandler(registers_t *regs) {
dbg_printf("Syscall %i (not implemented yet)\n", regs->int_no);
// do nothing, yet.
}
/* For internal use only. Sets up an entry of the IDT with given parameters. */
static void idt_set_gate(uint8_t num, void (*fun)(), uint8_t type) {
uint32_t base = (uint32_t)fun;
idt_entries[num].base_lo = base & 0xFFFF;
idt_entries[num].base_hi = (base >> 16) & 0xFFFF;
idt_entries[num].sel = K_CODE_SEGMENT;
idt_entries[num].always0 = 0;
idt_entries[num].type_attr = GATE_PRESENT
| (3 << GATE_DPL_SHIFT) // accessible from user mode
| type;
}
static const struct {
uint8_t num;
void (*fun)();
uint8_t type;
} gates[] = {
// Most processor exceptions are traps and handling them
// should be preemptible
{ 0, isr0, GATE_TYPE_TRAP },
{ 1, isr1, GATE_TYPE_TRAP },
{ 2, isr2, GATE_TYPE_TRAP },
{ 3, isr3, GATE_TYPE_TRAP },
{ 4, isr4, GATE_TYPE_TRAP },
{ 5, isr5, GATE_TYPE_TRAP },
{ 6, isr6, GATE_TYPE_TRAP },
{ 7, isr7, GATE_TYPE_TRAP },
{ 8, isr8, GATE_TYPE_TRAP },
{ 9, isr9, GATE_TYPE_TRAP },
{ 10, isr10, GATE_TYPE_TRAP },
{ 11, isr11, GATE_TYPE_TRAP },
{ 12, isr12, GATE_TYPE_TRAP },
{ 13, isr13, GATE_TYPE_TRAP },
{ 14, isr14, GATE_TYPE_INTERRUPT }, // reenables interrupts later on
{ 15, isr15, GATE_TYPE_TRAP },
{ 16, isr16, GATE_TYPE_TRAP },
{ 17, isr17, GATE_TYPE_TRAP },
{ 18, isr18, GATE_TYPE_TRAP },
{ 19, isr19, GATE_TYPE_TRAP },
{ 20, isr20, GATE_TYPE_TRAP },
{ 21, isr21, GATE_TYPE_TRAP },
{ 22, isr22, GATE_TYPE_TRAP },
{ 23, isr23, GATE_TYPE_TRAP },
{ 24, isr24, GATE_TYPE_TRAP },
{ 25, isr25, GATE_TYPE_TRAP },
{ 26, isr26, GATE_TYPE_TRAP },
{ 27, isr27, GATE_TYPE_TRAP },
{ 28, isr28, GATE_TYPE_TRAP },
{ 29, isr29, GATE_TYPE_TRAP },
{ 30, isr30, GATE_TYPE_TRAP },
{ 31, isr31, GATE_TYPE_TRAP },
// IRQs are not preemptible ; an IRQ handler should do the bare minimum
// (communication with the hardware), and then pass a message to a worker
// process in order to do further processing
{ 32, irq0, GATE_TYPE_INTERRUPT },
{ 33, irq1, GATE_TYPE_INTERRUPT },
{ 34, irq2, GATE_TYPE_INTERRUPT },
{ 35, irq3, GATE_TYPE_INTERRUPT },
{ 36, irq4, GATE_TYPE_INTERRUPT },
{ 37, irq5, GATE_TYPE_INTERRUPT },
{ 38, irq6, GATE_TYPE_INTERRUPT },
{ 39, irq7, GATE_TYPE_INTERRUPT },
{ 40, irq8, GATE_TYPE_INTERRUPT },
{ 41, irq9, GATE_TYPE_INTERRUPT },
{ 42, irq10, GATE_TYPE_INTERRUPT },
{ 43, irq11, GATE_TYPE_INTERRUPT },
{ 44, irq12, GATE_TYPE_INTERRUPT },
{ 45, irq13, GATE_TYPE_INTERRUPT },
{ 46, irq14, GATE_TYPE_INTERRUPT },
{ 47, irq15, GATE_TYPE_INTERRUPT },
// Of course, syscalls are preemptible
{ 64, syscall64, GATE_TYPE_TRAP },
{ 0, 0, 0 }
};
/* Remaps the IRQs. Sets up the IDT. */
void idt_init() {
memset((uint8_t*)&idt_entries, 0, sizeof(idt_entry_t) * 256);
//Remap the IRQ table
outb(0x20, 0x11);
outb(0xA0, 0x11);
outb(0x21, 0x20);
outb(0xA1, 0x28);
outb(0x21, 0x04);
outb(0xA1, 0x02);
outb(0x21, 0x01);
outb(0xA1, 0x01);
outb(0x21, 0x0);
outb(0xA1, 0x0);
for (int i = 0; gates[i].type != 0; i++) {
idt_set_gate(gates[i].num, gates[i].fun, gates[i].type);
}
idt_ptr.limit = (sizeof(idt_entry_t) * 256) - 1;
idt_ptr.base = (uint32_t)&idt_entries;
asm volatile ("lidt %0"::"m"(idt_ptr):"memory");
// Some setup calls that come later on are not preemptible,
// so we wait until then to enable interrupts.
}
/* Sets up an IRQ handler for given IRQ. */
void idt_set_irq_handler(int number, isr_handler_t func) {
if (number < 16 && number >= 0) {
irq_handlers[number] = func;
}
}
/* Sets up a handler for a processor exception */
void idt_set_ex_handler(int number, isr_handler_t func) {
if (number >= 0 && number < 32) {
ex_handlers[number] = func;
}
}
void dbg_dump_registers(registers_t *regs) {
dbg_printf("/ Exception %i\n", regs->int_no);
dbg_printf("| EAX: 0x%p EBX: 0x%p ECX: 0x%p EDX: 0x%p\n", regs->eax, regs->ebx, regs->ecx, regs->edx);
dbg_printf("| EDI: 0x%p ESI: 0x%p ESP: 0x%p EBP: 0x%p\n", regs->edi, regs->esi, regs->esp, regs->ebp);
dbg_printf("| EIP: 0x%p CS : 0x%p DS : 0x%p SS : 0x%p\n", regs->eip, regs->cs, regs->ds, regs->ss);
dbg_printf("\\ EFl: 0x%p I# : 0x%p Err: 0x%p\n", regs->eflags, regs->int_no, regs->err_code);
}
/* vim: set ts=4 sw=4 tw=0 noet :*/
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