banan-os/kernel/arch/i386/IDT.cpp

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#include <kernel/IDT.h>
#include <kernel/kmalloc.h>
#include <kernel/panic.h>
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#include <kernel/PIC.h>
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#include <kernel/kprint.h>
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union GateDescriptor
{
struct
{
uint16_t offset_lo;
uint16_t selector;
uint8_t reserved;
uint8_t type : 4;
uint8_t zero : 1;
uint8_t dpl : 2;
uint8_t present : 1;
uint16_t offset_hi;
};
struct
{
uint32_t low;
uint32_t high;
};
} __attribute__((packed));
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struct IDTR
{
uint16_t size;
void* offset;
} __attribute((packed));
static IDTR s_idtr;
static GateDescriptor* s_idt;
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static void (*s_irq_handlers[16])();
extern "C" void handle_irq();
extern "C" void handle_irq_common();
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#define INTERRUPT_HANDLER(i, msg) \
static void interrupt ## i () \
{ \
uint32_t cr0, cr2, cr3, cr4; \
asm volatile("movl %%cr0, %%eax":"=a"(cr0)); \
asm volatile("movl %%cr2, %%eax":"=a"(cr2)); \
asm volatile("movl %%cr3, %%eax":"=a"(cr3)); \
asm volatile("movl %%cr4, %%eax":"=a"(cr4)); \
Kernel::panic(msg ", CR0={} CR2={} CR3={} CR4={}", cr0, cr2, cr3, cr4); \
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}
INTERRUPT_HANDLER(0x00, "Divide error")
INTERRUPT_HANDLER(0x01, "Debug exception")
INTERRUPT_HANDLER(0x02, "Unknown error")
INTERRUPT_HANDLER(0x03, "Breakpoint")
INTERRUPT_HANDLER(0x04, "Overflow")
INTERRUPT_HANDLER(0x05, "Bounds check")
INTERRUPT_HANDLER(0x06, "Invalid opcode")
INTERRUPT_HANDLER(0x07, "Coprocessor not available")
INTERRUPT_HANDLER(0x08, "Double fault")
INTERRUPT_HANDLER(0x09, "Coprocessor segment overrun")
INTERRUPT_HANDLER(0x0a, "Invalid TSS")
INTERRUPT_HANDLER(0x0b, "Segment not present")
INTERRUPT_HANDLER(0x0c, "Stack exception")
INTERRUPT_HANDLER(0x0d, "General protection fault")
INTERRUPT_HANDLER(0x0e, "Page fault")
INTERRUPT_HANDLER(0x0f, "Unknown error")
INTERRUPT_HANDLER(0x10, "Coprocessor error")
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#define REGISTER_HANDLER(i) register_interrupt_handler(i, interrupt ## i)
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void handle_irq()
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{
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uint16_t isr = PIC::get_isr();
if (!isr) {
kprint("Spurious IRQ\n");
return;
}
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uint8_t irq = 0;
for (uint8_t i = 0; i < 16; ++i) {
if (i == 2)
continue;
if (isr & (1 << i)) {
irq = i;
break;
}
}
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if (s_irq_handlers[irq])
s_irq_handlers[irq]();
else
kprint("no handler for irq {}\n", irq);
PIC::eoi(irq);
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}
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namespace IDT
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{
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static void flush_idt()
{
asm volatile("lidt %0"::"m"(s_idtr));
}
static void unimplemented_trap()
{
Kernel::panic("Unhandeled IRQ");
}
static void register_interrupt_handler(uint8_t index, void (*f)())
{
s_idt[index].low = 0x00080000 | ((uint32_t)(f) & 0x0000ffff);
s_idt[index].high = ((uint32_t)(f) & 0xffff0000) | 0x8e00;
flush_idt();
}
void register_irq_handler(uint8_t irq, void (*f)())
{
s_irq_handlers[irq] = f;
register_interrupt_handler(IRQ_VECTOR_BASE + irq, handle_irq_common);
}
void initialize()
{
constexpr size_t idt_size = 256;
s_idt = new GateDescriptor[idt_size];
s_idtr.offset = s_idt;
s_idtr.size = idt_size * 8;
for (uint8_t i = 0xff; i > 0x10; i--)
register_interrupt_handler(i, unimplemented_trap);
REGISTER_HANDLER(0x00);
REGISTER_HANDLER(0x01);
REGISTER_HANDLER(0x02);
REGISTER_HANDLER(0x03);
REGISTER_HANDLER(0x04);
REGISTER_HANDLER(0x05);
REGISTER_HANDLER(0x06);
REGISTER_HANDLER(0x07);
REGISTER_HANDLER(0x08);
REGISTER_HANDLER(0x09);
REGISTER_HANDLER(0x0a);
REGISTER_HANDLER(0x0b);
REGISTER_HANDLER(0x0c);
REGISTER_HANDLER(0x0d);
REGISTER_HANDLER(0x0e);
REGISTER_HANDLER(0x0f);
REGISTER_HANDLER(0x10);
for (uint8_t i = 0; i < sizeof(s_irq_handlers) / sizeof(*s_irq_handlers); i++)
s_irq_handlers[i] = nullptr;
flush_idt();
}
}