/**
* Check page table
*/
void check_pgdir(void)
{
assert(npage <= KMEMSIZE / PGSIZE);
assert(boot_pgdir != NULL && (uint32_t) PGOFF(boot_pgdir) == 0);
assert(get_page(boot_pgdir, TEST_PAGE, NULL) == NULL);
struct Page *p1, *p2;
p1 = alloc_page();
assert(page_insert(boot_pgdir, p1, TEST_PAGE, 0) == 0);
pte_t *ptep, perm;
assert((ptep = get_pte(boot_pgdir, TEST_PAGE, 0)) != NULL);
assert(pa2page(*ptep) == p1);
assert(page_ref(p1) == 1);
ptep = &((pte_t *) KADDR(PTE_ADDR(boot_pgdir[PDX(TEST_PAGE)])))[1];
assert(get_pte(boot_pgdir, TEST_PAGE + PGSIZE, 0) == ptep);
p2 = alloc_page();
ptep_unmap(&perm);
ptep_set_u_read(&perm);
ptep_set_u_write(&perm);
assert(page_insert(boot_pgdir, p2, TEST_PAGE + PGSIZE, perm) == 0);
assert((ptep = get_pte(boot_pgdir, TEST_PAGE + PGSIZE, 0)) != NULL);
assert(ptep_u_read(ptep));
assert(ptep_u_write(ptep));
assert(ptep_u_read(&(boot_pgdir[PDX(TEST_PAGE)])));
assert(page_ref(p2) == 1);
assert(page_insert(boot_pgdir, p1, TEST_PAGE + PGSIZE, 0) == 0);
assert(page_ref(p1) == 2);
assert(page_ref(p2) == 0);
assert((ptep = get_pte(boot_pgdir, TEST_PAGE + PGSIZE, 0)) != NULL);
assert(pa2page(*ptep) == p1);
assert(!ptep_u_read(ptep));
page_remove(boot_pgdir, TEST_PAGE);
assert(page_ref(p1) == 1);
assert(page_ref(p2) == 0);
page_remove(boot_pgdir, TEST_PAGE + PGSIZE);
assert(page_ref(p1) == 0);
assert(page_ref(p2) == 0);
assert(page_ref(pa2page(boot_pgdir[PDX(TEST_PAGE)])) == 1);
free_page(pa2page(boot_pgdir[PDX(TEST_PAGE)]));
boot_pgdir[PDX(TEST_PAGE)] = 0;
exit_range(boot_pgdir, TEST_PAGE, TEST_PAGE + PGSIZE);
kprintf("check_pgdir() succeeded.\n");
}
/* use software emulated X86 pgfault */
static void handle_tlbmiss(struct trapframe* tf, int write)
{
#if 0
if(!trap_in_kernel(tf)){
print_trapframe(tf);
while(1);
}
#endif
static int entercnt = 0;
entercnt ++;
//kprintf("## enter handle_tlbmiss %d times\n", entercnt);
int in_kernel = trap_in_kernel(tf);
assert(current_pgdir != NULL);
//print_trapframe(tf);
uint32_t badaddr = tf->tf_vaddr;
int ret = 0;
pte_t *pte = get_pte(current_pgdir, tf->tf_vaddr, 0);
if(pte==NULL || ptep_invalid(pte)){ //PTE miss, pgfault
//panic("unimpl");
//TODO
//tlb will not be refill in do_pgfault,
//so a vmm pgfault will trigger 2 exception
//permission check in tlb miss
ret = pgfault_handler(tf, badaddr, get_error_code(write, pte));
}else{ //tlb miss only, reload it
/* refill two slot */
/* check permission */
if(in_kernel){
tlb_refill(badaddr, pte);
//kprintf("## refill K\n");
return;
}else{
if(!ptep_u_read(pte)){
ret = -1;
goto exit;
}
if(write && !ptep_u_write(pte)){
ret = -2;
goto exit;
}
//kprintf("## refill U %d %08x\n", write, badaddr);
tlb_refill(badaddr, pte);
return ;
}
}
exit:
if(ret){
print_trapframe(tf);
if(in_kernel){
panic("unhandled pgfault");
}else{
do_exit(-E_KILLED);
}
}
return ;
}
/* ucore use copy-on-write when forking a new process,
* thus copy_range only copy pdt/pte and set their permission to
* READONLY, a write will be handled in pgfault
*/
int
copy_range(pgd_t *to, pgd_t *from, uintptr_t start, uintptr_t end, bool share) {
assert(start % PGSIZE == 0 && end % PGSIZE == 0);
assert(USER_ACCESS(start, end));
do {
pte_t *ptep = get_pte(from, start, 0), *nptep;
if (ptep == NULL) {
if (get_pud(from, start, 0) == NULL) {
start = ROUNDDOWN(start + PUSIZE, PUSIZE);
}
else if (get_pmd(from, start, 0) == NULL) {
start = ROUNDDOWN(start + PMSIZE, PMSIZE);
}
else {
start = ROUNDDOWN(start + PTSIZE, PTSIZE);
}
continue ;
}
if (*ptep != 0) {
if ((nptep = get_pte(to, start, 1)) == NULL) {
return -E_NO_MEM;
}
int ret;
//kprintf("%08x %08x %08x\n", nptep, *nptep, start);
assert(*ptep != 0 && *nptep == 0);
#ifdef ARCH_ARM
//TODO add code to handle swap
if (ptep_present(ptep)){
//no body should be able to write this page
//before a W-pgfault
pte_perm_t perm = PTE_P;
if(ptep_u_read(ptep))
perm |= PTE_U;
if(!share){
//Original page should be set to readonly!
//because Copy-on-write may happen
//after the current proccess modifies its page
ptep_set_perm(ptep, perm);
}else{
if(ptep_u_write(ptep)){
perm |= PTE_W;
}
}
struct Page *page = pte2page(*ptep);
ret = page_insert(to, page, start, perm);
}
#else /* ARCH_ARM */
if (ptep_present(ptep)) {
pte_perm_t perm = ptep_get_perm(ptep, PTE_USER);
struct Page *page = pte2page(*ptep);
if (!share && ptep_s_write(ptep)) {
ptep_unset_s_write(&perm);
pte_perm_t perm_with_swap_stat = ptep_get_perm(ptep, PTE_SWAP);
ptep_set_perm(&perm_with_swap_stat, perm);
page_insert(from, page, start, perm_with_swap_stat);
}
ret = page_insert(to, page, start, perm);
assert(ret == 0);
}
#endif /* ARCH_ARM */
else {
#ifdef CONFIG_NO_SWAP
assert(0);
#endif
swap_entry_t entry;
ptep_copy(&entry, ptep);
swap_duplicate(entry);
ptep_copy(nptep, &entry);
}
}
start += PGSIZE;
} while (start != 0 && start < end);
#ifdef ARCH_ARM
/* we have modified the PTE of the original
* process, so invalidate TLB */
tlb_invalidate_all();
#endif
return 0;
}
