Nathan Giddings
108e04a8f0
Rather than contantly checking if a page table exists before access, the fault handler will automatically allocate them as needed.
110 lines
2.6 KiB
C
110 lines
2.6 KiB
C
#include "x86/isr.h"
|
|
#include "stdio.h"
|
|
#include "x86/apic.h"
|
|
#include "platform/interrupts.h"
|
|
#include "mmgr.h"
|
|
#include "string.h"
|
|
#include "kernel.h"
|
|
|
|
#include <stdint.h>
|
|
|
|
struct interrupt_frame_t
|
|
{
|
|
uint32_t eip;
|
|
uint32_t cs;
|
|
uint32_t eflags;
|
|
uint32_t esp;
|
|
uint32_t ss;
|
|
};
|
|
|
|
typedef struct page_fault_code_t
|
|
{
|
|
uint32_t present : 1;
|
|
uint32_t write : 1;
|
|
uint32_t usermode : 1;
|
|
uint32_t reserved : 1;
|
|
uint32_t inst_fetch : 1;
|
|
uint32_t pk : 1;
|
|
uint32_t shadow_stack : 1;
|
|
uint32_t padding : 25;
|
|
} page_fault_code_t;
|
|
|
|
void isr_generic(struct interrupt_frame_t *frame)
|
|
{
|
|
printf("Generic interrupt.\n");
|
|
}
|
|
|
|
void isr_division_by_zero(struct interrupt_frame_t *frame)
|
|
{
|
|
printf("Exception: Division by zero\n");
|
|
}
|
|
|
|
void isr_segment_not_present(struct interrupt_frame_t *frame, unsigned int error)
|
|
{
|
|
irq_disable();
|
|
printf("Exception: NP fault, code %08x\n", error);
|
|
asm("hlt");
|
|
}
|
|
|
|
void isr_gp_fault(struct interrupt_frame_t *frame, unsigned int error)
|
|
{
|
|
irq_disable();
|
|
asm("mov $0x10, %%ax; "
|
|
"mov %%ax, %%ds; "
|
|
"mov %%ax, %%es; "
|
|
"mov %%ax, %%fs; "
|
|
"mov %%ax, %%gs; " ::
|
|
: "ax");
|
|
printf("Exception: GP fault, code %08x\n", error);
|
|
asm("hlt");
|
|
}
|
|
|
|
void isr_page_fault(struct interrupt_frame_t *frame, unsigned int error)
|
|
{
|
|
page_fault_code_t *code = &error;
|
|
uint32_t addr;
|
|
asm("mov %%cr2, %0"
|
|
: "=r"(addr));
|
|
asm("mov $0x10, %%ax; "
|
|
"mov %%ax, %%ds; "
|
|
"mov %%ax, %%es; "
|
|
"mov %%ax, %%fs; "
|
|
"mov %%ax, %%gs; " ::
|
|
: "ax");
|
|
if(code->usermode == 0
|
|
&& code->present == 0
|
|
&& addr >= 0xFFC00000
|
|
&& addr < 0xFFFFF000)
|
|
{
|
|
printf("Allocating new page table %08x within fault handler.\n", addr);
|
|
physaddr_t new_table = reserve_page();
|
|
if(new_table == ENOMEM)
|
|
{
|
|
kernel_panic("Out of memory while allocating page table.\n");
|
|
}
|
|
set_pte((void*)addr, 1, PAGE_PRESENT | PAGE_USERMODE | PAGE_RW, new_table);
|
|
asm volatile("mov %%cr3, %%eax;"
|
|
"mov %%eax, %%cr3" ::
|
|
: "eax", "memory");
|
|
memset((void*)(addr & ~0xFFF), 0, page_size);
|
|
}
|
|
else
|
|
{
|
|
printf("Exception: Page fault, code %08x, linear address %08x\n", error, addr);
|
|
kernel_panic("Unhandled page fault.\n");
|
|
}
|
|
}
|
|
|
|
void isr_double_fault(struct interrupt_frame_t *frame, unsigned int error)
|
|
{
|
|
irq_disable();
|
|
printf("Exception: Double fault (!!), code %08x\n", error);
|
|
asm("hlt");
|
|
}
|
|
|
|
void isr_timer(struct interrupt_frame_t *frame)
|
|
{
|
|
printf("Timer tick.\n");
|
|
apic_eoi();
|
|
}
|