void paging_handle_fault(void *virt_addr, void * instr_ptr, void *state, size_t state_size, int present, int write, int user)
{
uintptr_t addr = (uintptr_t) virt_addr;
physaddr_t phys_addr;
//earlycon_printf("\n PF: 0x%x at IP:0x%x\n", virt_addr, instr_ptr);
//debugcon_printf("[0x%x] page fault in %i @ 0x%x (P:%i, W:%i, U:%i) \n", virt_addr, curpid(), instr_ptr, present, user, write);
/* Handle page fault here */
if (user && (addr > 0xC0000000)) {
//TODO: Dispatch exception, usermode program tried to access kernel space
//debugcon_printf("umode violation!");
debugcon_printf("[0x%x] page fault in %i @ 0x%x (P:%i, W:%i, U:%i) \n", virt_addr, curpid(), instr_ptr, present, user, write);
exception_handle(EXCEPTION_PAGE_FAULT, instr_ptr, state, state_size);
}
if (!present) {
if ((addr >= 0xBFFF0000) && (addr < 0xBFFFB000)) {
/* Task stack area, add more stack */
virt_addr = (void *)(addr & ~PHYSMM_PAGE_ADDRESS_MASK);
phys_addr = physmm_alloc_frame();
if (phys_addr == PHYSMM_NO_FRAME) {
paging_handle_out_of_memory();
phys_addr = physmm_alloc_frame();
}
//TODO: Assess potential for race conditions
paging_map(virt_addr, phys_addr, PAGING_PAGE_FLAG_RW | PAGING_PAGE_FLAG_USER);
paging_tag(virt_addr, PAGING_PAGE_TAG_USER_DATA);
} else if ((addr >= 0xE0000000) && (addr < 0xFFC00000)) {
/* Kernel heap, check whether we have previously swapped out this page */
//TODO: Swapping, for now: PANIC!!!
//TODO: PANIC!
debugcon_printf("[0x%x] page fault in %i @ 0x%x (P:%i, W:%i, U:%i) \n", virt_addr, curpid(), instr_ptr, present, user, write);
exception_handle(EXCEPTION_PAGE_FAULT, instr_ptr, state, state_size);
} else if (addr < 0xC0000000){
/* Application space page fault */
//TODO: Check for dynamic libraries, mmapped files and swapped out pages
//TODO: If no fix was found, dispatch exception
if (!procvmm_handle_fault(virt_addr)){
debugcon_printf("[0x%x] page fault in %i @ 0x%x (P:%i, W:%i, U:%i) \n", virt_addr, curpid(), instr_ptr, present, user, write);
exception_handle(EXCEPTION_PAGE_FAULT, instr_ptr, state, state_size);
}
} else {
exception_handle(EXCEPTION_PAGE_FAULT, instr_ptr, state, state_size);
debugcon_printf("[0x%x] page fault in %i @ 0x%x (P:%i, W:%i, U:%i) \n", virt_addr, curpid(), instr_ptr, present, user, write);
}
} else if (write) {
//TODO: Copy on write,
debugcon_printf("[0x%x] page fault in %i @ 0x%x (P:%i, W:%i, U:%i) \n", virt_addr, curpid(), instr_ptr, present, user, write);
exception_handle(EXCEPTION_PAGE_FAULT, instr_ptr, state, state_size);
}
}
cpu_state_t* handle_interrupt(cpu_state_t* cpu) {
cpu_state_t* new_cpu = cpu;
if (cpu->intr <= 0x1f) {
exception_handle(cpu);
} else if (cpu->intr >= 0x20 && cpu->intr <= 0x2f) {
if (cpu->intr == 0x20) { // Timer
new_cpu = schedule(cpu);
} else {
new_cpu = interrupt(cpu);
}
if (cpu->intr >= 0x28) {
outb(0xa0, 0x20);
}
outb(0x20, 0x20);
} else if (cpu->intr == 0x30) {
new_cpu = syscall(cpu);
}
if (cpu != new_cpu) {
tss[1] = (uint32_t) (new_cpu + 1);
}
return new_cpu;
}
