diff options
Diffstat (limited to 'boot/idt.zig')
| -rw-r--r-- | boot/idt.zig | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/boot/idt.zig b/boot/idt.zig index a9898d6..fda5b9d 100644 --- a/boot/idt.zig +++ b/boot/idt.zig @@ -160,7 +160,7 @@ export fn exceptionHandler(frame: *Frame) callconv(.c) noreturn { while (true) asm volatile ("hlt"); } -// hardware IRQ. +// hardware IRQ // unlike exceptions these must return so we acknowledge the PIC and iretq // back to whatever we interrupted. the stub mirrors the exception one (dummy // error code + vector for a uniform Frame) but jumps to the returning path. @@ -225,12 +225,14 @@ export fn irqDispatch(frame: *Frame) callconv(.c) void { pic.eoi(@intCast(frame.vector - pic.MASTER_OFFSET)); } -fn setGate(vector: u8, handler: u64) void { +// dpl 0 = only ring 0 can invoke via `int` +// dpl 3 = ring 3 may (for syscalls) +pub fn setGate(vector: u8, handler: u64, dpl: u2) void { idt[vector] = .{ .offset_low = @truncate(handler), .selector = gdt.KERNEL_CODE, .ist = 0, - .type_attr = 0x8E, + .type_attr = 0x8E | (@as(u8, dpl) << 5), .offset_mid = @truncate(handler >> 16), .offset_high = @truncate(handler >> 32), .reserved = 0, @@ -239,10 +241,10 @@ fn setGate(vector: u8, handler: u64) void { // fill the exception vectors and load the IDT pub fn init() void { - inline for (0..32) |v| setGate(v, @intFromPtr(&stub(v))); + inline for (0..32) |v| setGate(v, @intFromPtr(&stub(v)), 0); // IRQ1 (keyboard) -> vector 0x21 // the PIC is remapped separately in boot. - setGate(pic.MASTER_OFFSET + 1, @intFromPtr(&irqStub(pic.MASTER_OFFSET + 1))); + setGate(pic.MASTER_OFFSET + 1, @intFromPtr(&irqStub(pic.MASTER_OFFSET + 1)), 0); idtr = .{ .limit = @sizeOf(@TypeOf(idt)) - 1, .base = @intFromPtr(&idt) }; asm volatile ("lidt (%[idtr])" : |