// top half page fault handler
void page_fault(registers_struct* regs)
{
uint32 addr;
_asm
{
mov eax, cr2
mov dword ptr addr, eax
}
// push thread in the exception queue
if (thread_get_current())
{
thread_exception te;
te.exception_number = 14;
te.target_thread = thread_get_current();
te.data[0] = addr;
te.data[1] = regs->err_code;
if (!queue_spsc_insert(&thread_get_current()->exceptions, te))
WARNING("queue_lf insertion error");
}
else
PANIC("Page fault occured but threading is not enabled!");
}
inline static bool thread_current_is_attached(void)
{
threadobject *t;
t = thread_get_current();
if (t == NULL)
return false;
return thread_is_attached(t);
}
uint32_t thread_get_pc(struct thread *t) {
if (t == NULL)
t = thread_get_current();
if (t == NULL) {
fprintf(stderr, "mvm: thread not initialized!\n");
mvm_halt();
}
return t->pc;
}
struct vm_stack * thread_get_vm_stack(struct thread *t) {
if (t == NULL)
t = thread_get_current();
if (t == NULL) {
fprintf(stderr, "mvm: thread not initialized!\n");
mvm_halt();
}
return t->vm_stack;
}
struct thread_dmp * thread_get_dmp(struct thread *t) {
if (t == NULL)
t = thread_get_current();
if (t == NULL) {
fprintf(stderr, "mvm: thread not initialized!\n");
mvm_halt();
}
return t->dmp;
}
int table_run_equals(struct table *t, struct object *o, struct object *p) {
int ref;
int32_t value;
uint32_t pc;
struct integer *integer;
struct object *object;
struct vm_stack *vm_stack;
struct frame *frame;
struct operand_stack *operand_stack;
struct thread *thread;
if (t == NULL) {
fprintf(stderr, "mvm: table not initialized!\n");
mvm_halt();
}
thread = thread_get_current();
pc = thread_get_pc(thread);
vm_stack = thread_get_vm_stack(thread);
frame = vm_stack_peek(vm_stack);
operand_stack = frame_get_operand_stack(frame);
operand_stack_push(operand_stack, object_get_ref(o));
operand_stack_push(operand_stack, object_get_ref(p));
invoke_virtual_method_by_name(thread, object_get_ref(o), pc, "equals", 1, "Object");
ref = operand_stack_peek(operand_stack);
object = heap_fetch_object(heap, ref);
integer = object_get_integer(object);
value = integer_get_value(integer);
operand_stack_pop(operand_stack);
return value;
}
/***
* Return the java.lang.Thread object for the current thread.
*/
inline static java_handle_t *thread_get_current_object(void) {
return LLNI_WRAP(thread_get_current()->object);
}
/* maThread = create_kernel_thread(
(kernel_thread_start_routine_t) Thread::start,
(void*) this);
}
void Threads::exit_thread(vaddr_t stack_vaddr) {
}*/
void Threads::suspend(int suspID){
sched_set_waiting(thread_get_current(),suspID);
}
void page_fault_bottom(thread_exception te)
{
thread_exception_print(&te);
uint32& addr = te.data[0];
uint32& code = te.data[1];
serial_printf("PAGE_FALUT: PROC: %u ADDRESS: %h, THREAD: %u, CODE: %h\n", process_get_current()->id, addr, thread_get_current()->id, code);
if (process_get_current()->contract_spinlock == 1)
PANIC("PAge fault spinlock is already reserved\n");
spinlock_acquire(&process_get_current()->contract_spinlock);
vm_area* p_area = vm_contract_find_area(&thread_get_current()->parent->memory_contract, addr);
if (p_area == 0)
{
serial_printf("could not find address %h in memory contract", addr);
PANIC(""); // terminate thread and process with SIGSEGV
}
vm_area area = *p_area;
spinlock_release(&process_get_current()->contract_spinlock);
// tried to acccess inaccessible page
if ((area.flags & MMAP_PROTECTION) == MMAP_NO_ACCESS)
{
serial_printf("address: %h is inaccessible\n", addr);
PANIC("");
}
// tried to write to read-only or inaccessible page
if (page_fault_error_is_write(code) && (area.flags & MMAP_WRITE) != MMAP_WRITE)
{
serial_printf("cannot write to address: %h\n", addr);
PANIC("");
}
// tried to read a write-only or inaccesible page ???what???
/*if (!page_fault_error_is_write(code) && CHK_BIT(area.flags, MMAP_READ))
{
serial_printf("cannot read from address: %h", addr);
PANIC("");
}*/
// if the page is present then a violation happened (we do not implement swap out/shared anonymous yet)
if (page_fault_error_is_page_present(code) == true)
{
serial_printf("memory violation at address: %h with code: %h\n", addr, code);
serial_printf("area flags: %h\n", area.flags);
PANIC("");
}
// here we found out that the page is not present, so we need to allocate it properly
if (CHK_BIT(area.flags, MMAP_PRIVATE))
{
if (CHK_BIT(area.flags, MMAP_ALLOC_IMMEDIATE))
{
// loop through all addresses and map them
for (virtual_addr address = area.start_addr; address < area.end_addr; address += 4096)
//if (CHK_BIT(area.flags, MMAP_ANONYMOUS)) ALLOC_IMMEDIATE works only for anonymous (imposed in mmap)
page_fault_alloc_page(area.flags, address);
}
else
{
if (CHK_BIT(area.flags, MMAP_ANONYMOUS))
page_fault_alloc_page(area.flags, addr & (~0xFFF));
else
{
uint32 flags = page_fault_calculate_present_flags(area.flags);
vmmngr_alloc_page_f(addr & (~0xFFF), flags);
uint32 read_start = area.offset + ((addr - area.start_addr) / PAGE_SIZE) * PAGE_SIZE; // file read start
uint32 read_size = PAGE_SIZE; // we read one page at a time (not the whole area as this may not be necessary)
//if (read_start < area.start_addr + PAGE_SIZE) // we are reading the first page so subtract offset from read_size
// read_size -= area.offset;
serial_printf("gfd: %u, reading at mem: %h, phys: %h file: %h, size: %u\n", area.fd, addr & (~0xfff), vmmngr_get_phys_addr(addr & (~0xfff)),
read_start, read_size);
gfe* entry = gft_get(area.fd);
if (entry == 0)
{
serial_printf("area.fd = %u", area.fd);
PANIC("page fault gfd entry = 0");
}
// read one page from the file offset given at the 4KB-aligned fault address
if (read_file_global(area.fd, read_start, read_size, addr & (~0xFFF), VFS_CAP_READ | VFS_CAP_CACHE) != read_size)
{
serial_printf("read fd: %u\n", area.fd);
PANIC("mmap anonymous file read less bytes than expected");
}
}
}
}
else // MMAP_SHARED
{
if (CHK_BIT(area.flags, MMAP_ANONYMOUS))
PANIC("A shared area cannot be marked as anonymous yet.");
else
{
// in the shared file mapping the address to read is ignored as data are read only to page cache.
uint32 read_start = area.offset + ((addr & (~0xfff)) - area.start_addr);
gfe* entry = gft_get(area.fd);
if (read_file_global(area.fd, read_start, PAGE_SIZE, -1, VFS_CAP_READ | VFS_CAP_CACHE) != PAGE_SIZE)
PANIC("mmap shared file failed");
virtual_addr used_cache = page_cache_get_buffer(area.fd, read_start / PAGE_SIZE);
//serial_printf("m%h\n", used_cache);
uint32 flags = page_fault_calculate_present_flags(area.flags);
vmmngr_map_page(vmmngr_get_directory(), vmmngr_get_phys_addr(used_cache), addr & (~0xfff), flags/*DEFAULT_FLAGS*/);
//serial_printf("shared mapping fd: %u, cache: %h, phys cache: %h, read: %u, addr: %h\n", area.fd, used_cache, used_cache, read_start, addr);
}
}
}
