89 lines
2.4 KiB
Zig
89 lines
2.4 KiB
Zig
// https://wiki.osdev.org/IDT
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const kernel = @import("kernel");
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const x86 = @import("x86");
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// Types of gates.
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pub const INTERRUPT_GATE = 0x8E;
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pub const SYSCALL_GATE = 0xEE;
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// Interrupt Descriptor Table.
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var idt_table: [256]IDTEntry = undefined;
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// IDT descriptor register pointing at the IDT.
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const idtr = IDTRegister{
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.limit = @as(u16, @sizeOf(@TypeOf(idt_table))),
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.base = &idt_table,
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};
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// Structure representing an entry in the IDT.
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const IDTEntry = packed struct {
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offset_low: u16,
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selector: u16,
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zero: u8,
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flags: u8,
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offset_high: u16,
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};
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// IDT descriptor register.
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const IDTRegister = packed struct {
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limit: u16,
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base: *[256]IDTEntry,
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};
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// Setup an IDT entry.
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//
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// Arguments:
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// n: Index of the gate.
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// flags: Type and attributes.
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// offset: Address of the ISR.
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//
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pub fn setGate(n: u8, flags: u8, offset: anytype) void {
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const intOffset = @ptrToInt(&offset);
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// const intOffset = offset;
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idt_table[n].offset_low = @truncate(u16, intOffset);
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idt_table[n].offset_high = @truncate(u16, intOffset >> 16);
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idt_table[n].flags = flags;
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idt_table[n].zero = 0;
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idt_table[n].selector = x86.gdt.KERNEL_CODE;
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}
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// Initialize the Interrupt Descriptor Table.
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pub fn initialize() void {
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// configure PIC
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x86.interrupt.remapPIC();
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x86.interrupt.configPIT();
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// install ISRs
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x86.isr.install_exceptions();
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x86.isr.install_irqs();
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x86.isr.install_syscalls();
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x86.interrupt.registerIRQ(0, kernel.time.increment);
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x86.interrupt.registerIRQ(1, kernel.ps2.keyboard_handler);
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x86.interrupt.register(1, debug_trap);
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x86.interrupt.register(13, general_protection_fault);
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x86.interrupt.register(14, page_fault);
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// load IDT
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x86.instr.lidt(@ptrToInt(&idtr));
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}
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fn general_protection_fault() void {
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kernel.println("general protection fault", .{});
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x86.instr.hang();
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}
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fn debug_trap() void {
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kernel.println("debug fault/trap", .{});
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kernel.println("dr7: 0b{b}", .{x86.instr.dr7()});
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}
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fn page_fault() void {
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const vaddr = x86.instr.cr2();
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kernel.println("cr2: 0x{x}", .{vaddr});
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kernel.println("phy: 0x{x}", .{kernel.paging.translate(vaddr)});
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kernel.println("pde: 0x{x} ({})", .{ kernel.paging.pde(vaddr), vaddr >> 22 });
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kernel.println("pte: 0x{x} ({})", .{ kernel.paging.pte(vaddr), vaddr >> 12 });
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// paging.format();
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x86.instr.hang();
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}
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