forked from BSB-WS23/mpstubs
64 lines
2.3 KiB
C++
64 lines
2.3 KiB
C++
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#include "machine/idt.h"
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#include "machine/gdt.h"
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#include "machine/core_interrupt.h"
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namespace IDT {
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// Interrupt Descriptor stored in the Interrupt-Descriptor Table (IDT)
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struct alignas(8) InterruptDescriptor {
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uint16_t address_low; ///< lower interrupt function offset
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uint16_t selector; ///< code segment selector in GDT or LDT
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union {
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struct {
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uint8_t ist : 3; ///< IST Index (64 bit)
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uint8_t : 5; ///< unused, has to be 0
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Gate type : 3; ///< gate type
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GateSize size : 1; ///< gate size
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uint8_t : 1; ///< unused, has to be 0
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DPL dpl : 2; ///< descriptor privilege level
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uint8_t present : 1; ///< present: 1 for interrupts
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} __attribute__((packed));
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uint16_t flags;
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};
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uint64_t address_high : 48; ///< higher interrupt function offset
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uint64_t : 0; ///< fill until aligned with 64 bit
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} __attribute__((packed));
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// Interrupt Descriptor Table, 8 Byte aligned
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static struct InterruptDescriptor idt[256];
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// Struct used for loading (the address of) the Interrupt Descriptor Table into the IDT-Register
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struct Register {
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uint16_t limit; // Address of the last valid byte (relative to base)
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struct InterruptDescriptor * base;
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explicit Register(uint8_t max = 255) {
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limit = (max + static_cast<uint16_t>(1)) * sizeof(InterruptDescriptor) - 1;
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base = idt;
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}
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} __attribute__((packed));
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static_assert(sizeof(InterruptDescriptor) == 16, "IDT::InterruptDescriptor has wrong size");
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static_assert(sizeof(Register) == 10, "IDT::Register has wrong size");
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static_assert(alignof(decltype(idt)) % 8 == 0, "IDT must be 8 byte aligned!");
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void load() {
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// Create structure required for writing to idtr and load via lidt
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Register idtr(Core::Interrupt::VECTORS - 1);
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asm volatile("lidt %0\n\t" :: "m"(idtr) );
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}
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void handle(uint8_t vector, void * handler, enum Gate type, enum GateSize size, enum DPL dpl, bool present) {
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struct InterruptDescriptor &item = idt[vector];
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item.selector = GDT::SEGMENT_KERNEL_CODE * sizeof(GDT::SegmentDescriptor);
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item.type = type;
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item.size = size;
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item.dpl = dpl;
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item.present = present ? 1 : 0;
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uintptr_t address = reinterpret_cast<uintptr_t>(handler);
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item.address_low = address & 0xffff;
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item.address_high = (address >> 16) & 0xffffffffffff;
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}
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} // namespace IDT
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