/*
* When the swapper has found a task it wishes to make run we do the
* dirty work. On failure we return -1
*/
static int make_runnable(register struct task_struct *t)
{
char flags = t->mm.flags;
if (flags & CS_SWAP)
if (swap_in(t->mm.cseg, 1) == -1)
return -1;
if (flags & DS_SWAP)
if (swap_in(t->mm.dseg, 0) == -1)
return -1;
return 0;
}
void page_replacement(void *vaddr)
{
uint32_t *paddr,*lru_page;
if ((paddr = palloc_get_page(PAL_USER)) != NULL)
swap_in(vaddr, paddr);
else
{
lru_page = lru_get_page();
swap_out(lru_page);
swap_in(vaddr,lru_page);
}
}
int page_fault(page_table_leaf_t *page_entry) {
frame_t victim = 0;
stats.page_faults++;
/*
* If there are no free frames, then we need to swap something out
*/
if( next_free_frame < 0 ) {
/*
* Pick a victim to swap out
*/
page_replacement_alg(&victim);
/*
* Swap out the page
*/
swap_out(victim);
}
/*
* Swap-In the page
*/
swap_in(page_entry);
return 0;
}
void do_pagefault(struct pf_msg *pmsg)
{
int frame;
int page;
verify_vm_access(pmsg->page_idx, pmsg->word_idx);
frame = find_pgt_index();
page = find_vm_index(frame);
lock_memory();
lock_vm();
lock_pagetable();
//printf("Swapping out frame %d\n", frame);
swap_out(page, frame);
usleep(F);
//printf("Swapping in page %d\n", pmsg->page_idx);
swap_in(pmsg->page_idx, frame);
usleep(F);
page_table[page] = -1;
page_table[pmsg->page_idx] = frame;
unlock_memory();
unlock_vm();
unlock_pagetable();
}
void asignar_marco(pagina_t* * pagina, segmento_t** segmento, uint32_t pid){
marco_t* marco=NULL;
marco = buscar_marco_libre();
//Si no hay ningun marco libre, swappeo
//Si hay un marco libre, se lo asigno a la pagina
if((*pagina)->en_disco){
swap_out(pid, (*segmento)->id, pagina);
}else{
if(marco == NULL){
swap_in(pagina, (*segmento)->id, pid);
}else{
(*pagina)->marco=marco->id;
(*pagina)->tiene_marco= true;
marco->id_proceso = pid;
marco->ocupado= true;
loggear_trace("Se asigno el marco %d a la pagina %d del segmento %d del proceso %d.",
marco->id, (*pagina)->id, (*segmento)->id, pid);
if(cantidad_marcos_libre() == 0){
loggear_info("Espacio de memoria principal lleno");
}
}
}
}
bool
spage_table_load (struct spage_table_entry *spte, enum spage_types type)
{
// P3: reduce race condition with frame eviction process.
spte->inevictable = true;
if (spte->in_memory) return false;
if (type == SWAP)
{
uint8_t *f = frame_alloc (PAL_USER, spte);
if (!f) return false;
if (!install_page (spte->upage, f, spte->writable))
{
frame_free (f);
return false;
}
swap_in (spte->swap_slot_id, spte->upage);
spte->in_memory = true;
}
if (type == FILE || type == MMAP)
{
enum palloc_flags fg = PAL_USER;
if (spte->file_read_bytes == 0) fg |= PAL_ZERO;
uint8_t *f = frame_alloc (fg, spte);
if (!f) return false;
if (spte->file_read_bytes > 0)
{
lock_acquire (&lock_f);
if ((int) spte->file_read_bytes != file_read_at (spte->file, f, spte->file_read_bytes,
spte->file_offset))
{
lock_release (&lock_f);
frame_free (f);
return false;
}
lock_release (&lock_f);
memset (f + spte->file_read_bytes, 0, spte->file_zero_bytes);
}
if (!install_page (spte->upage, f, spte->writable))
{
frame_free (f);
return false;
}
spte->in_memory = true;
}
return true;
}
/**
* unmap_virtual_page - poistetaan virtuaalisen sivun osoitus
* @phys_pd: käytettävän sivuhakemiston fyysinen sivu
* @virt_page: sivu, joka pitää osoittaa
**/
void unmap_virtual_page(uint_t phys_pd, uint_t virt_page)
{
uint_t new_location;
uint_t pde, pte;
page_entry_t *pd, *pt;
pde = virt_page / MEMORY_PE_COUNT;
pte = virt_page % MEMORY_PE_COUNT;
if (!phys_pd) {
phys_pd = cur_phys_pd();
}
pd = temp_page_directory(phys_pd);
if (pd[pde].pagenum == 0) {
panic("unmap_virtual_page: (pd[pde].pagenum == 0)!");
}
if (!pd[pde].present) {
new_location = swap_in(phys_pd, pd[pde].pagenum);
if (!new_location) {
panic("unmap_virtual_page (3)");
}
pd[pde].pagenum = new_location;
pd[pde].present = 1;
}
pt = temp_page_directory(pd[pde].pagenum);
if (pt[pte].pagenum == 0) {
panic("unmap_virtual_page: (pt[pte].pagenum == 0)!");
}
if (!pt[pte].present) {
new_location = swap_in(phys_pd, pt[pte].pagenum);
if (!new_location) {
panic("unmap_virtual_page (4)");
}
pt[pte].pagenum = new_location;
pt[pte].present = 1;
}
free_phys_page(pt[pte].pagenum);
pt[pte] = NULL_PE;
flush_pagedir(phys_pd);
return;
}
/*===========================================================================*
* main *
*===========================================================================*/
PUBLIC int main()
{
/* Main routine of the process manager. */
int result, s, proc_nr;
struct mproc *rmp;
sigset_t sigset;
pm_init(); /* initialize process manager tables */
/* This is PM's main loop- get work and do it, forever and forever. */
while (TRUE) {
get_work(); /* wait for an PM system call */
/* Check for system notifications first. Special cases. */
if (call_nr == SYN_ALARM) {
pm_expire_timers(m_in.NOTIFY_TIMESTAMP);
result = SUSPEND; /* don't reply */
} else if (call_nr == SYS_SIG) { /* signals pending */
sigset = m_in.NOTIFY_ARG;
if (sigismember(&sigset, SIGKSIG)) (void) ksig_pending();
result = SUSPEND; /* don't reply */
}
/* Else, if the system call number is valid, perform the call. */
else if ((unsigned) call_nr >= NCALLS) {
result = ENOSYS;
} else {
result = (*call_vec[call_nr])();
}
/* Send the results back to the user to indicate completion. */
if (result != SUSPEND) setreply(who, result);
swap_in(); /* maybe a process can be swapped in? */
/* Send out all pending reply messages, including the answer to
* the call just made above. The processes must not be swapped out.
*/
for (proc_nr=0, rmp=mproc; proc_nr < NR_PROCS; proc_nr++, rmp++) {
/* In the meantime, the process may have been killed by a
* signal (e.g. if a lethal pending signal was unblocked)
* without the PM realizing it. If the slot is no longer in
* use or just a zombie, don't try to reply.
*/
if ((rmp->mp_flags & (REPLY | ONSWAP | IN_USE | ZOMBIE)) ==
(REPLY | IN_USE)) {
if ((s=send(proc_nr, &rmp->mp_reply)) != OK) {
panic(__FILE__,"PM can't reply to", proc_nr);
}
rmp->mp_flags &= ~REPLY;
}
}
}
return(OK);
}
/*
* page fault handler
* - it deals with 4 scenarios:
* - expand user space stack
* - swap process in
* - do copy-on-write
* - handle segment fault
*/
void trap_memory_handler(struct user_context *user_ctx)
{
unsigned long addr = (unsigned long)user_ctx->addr;
unsigned int page_index = PAGE_UINDEX(addr);
struct my_pte *ptep = current->page_table + page_index;
int ret;
_enter("pid = %u, at %p(%u), code = %d",
current->pid, addr, page_index, user_ctx->code);
switch (user_ctx->code) {
case YALNIX_MAPERR:
/* expand stack */
if (!ptep->swap && page_index == current->stack_start - 1) {
task_vm_expand_stack(current, 1);
break;
}
/* swap process in */
if (ptep->swap) {
ret = swap_in(current);
if (ret == EIO) {
sys_tty_write(0, "Abort! Swap In error!\n",
64, user_ctx);
sys_exit(ret, user_ctx);
}
}
break;
case YALNIX_ACCERR:
break;
default:
#ifdef COW
/* do copy-on-write for the parent and children */
if (ptep->cow && ptep->prot == PROT_READ) {
task_cow_copy_page(current, page_index);
break;
}
#endif
/* if tried to write text segment just abort it */
if (ptep->prot == (PROT_READ | PROT_EXEC)) {
sys_tty_write(0, "Abort! Segment Fault!\n",
64, user_ctx);
sys_exit(ERROR, user_ctx);
}
break;
}
_leave();
return;
}
/*
* Reload line number information from swap.
*/
void load_line_numbers(program_t * prog)
{
int size;
if (prog->line_info)
return;
debug(d_flag, ("Unswap line numbers for /%s\n", prog->name));
size = swap_in((char **) &prog->file_info, prog->line_swap_index);
SET_TAG(prog->file_info, TAG_LINENUMBERS);
prog->line_info = (unsigned char *)&prog->file_info[prog->file_info[1]];
line_num_bytes_swapped -= size;
}
/**
* temp_virt_page - väliaikainen käyttökelpoinen osoitin toisen taulun sivuun
* @page: virtuaalisivun numero (ei oikea sivunumero vaan tämän funktion asia)
* @phys_pd: fyysinen sivu, jolla sivutaulu sijaitsee, tai 0 poistoa varten
* @virt_page: haettavan virtuaalisen sivun numero tai 0 poistoa varten
**/
void * temp_virt_page(uint_t page, uint_t phys_pd, uint_t virt_page)
{
page_entry_t *pd, *pt;
uint_t new_location;
if (!phys_pd || !virt_page) {
return temp_phys_page(page, 0);
}
uint_t pde = virt_page / MEMORY_PE_COUNT;
uint_t pte = virt_page % MEMORY_PE_COUNT;
if (!(pd = temp_page_directory(phys_pd)) || !pd[pde].pagenum) {
return 0;
}
if (!pd[pde].present) {
new_location = swap_in(phys_pd, pd[pde].pagenum);
if (!new_location) {
return 0;
}
pd[pde].pagenum = new_location;
pd[pde].present = 1;
}
if (!(pt = temp_page_table(pd[pde].pagenum)) || !pt[pte].pagenum) {
return 0;
}
if (!pt[pte].present) {
new_location = swap_in(phys_pd, pt[pte].pagenum);
if (!new_location) {
return 0;
}
pt[pte].pagenum = new_location;
pt[pte].present = 1;
}
return temp_phys_page(page, pt[pte].pagenum);
}
paddr_t page_fault(vaddr_t faultaddress,struct page_table_entry *pt_entry_temp2)
{
struct page_table_entry *pt_entry = curthread->t_addrspace->page_table ;
struct page_table_entry *pt_entry_temp = NULL;
while(pt_entry != NULL){
if(pt_entry->va == faultaddress) // Additional checks to be implemented later
{
if(pt_entry->state == PAGE_IN_MEMORY){
pt_entry_temp2->state = 1000;
struct coremap *local_coremap = coremap_list;
while(local_coremap!=NULL){
if(local_coremap->pa == pt_entry->pa){
local_coremap->timestamp = localtime++;
break;
}
local_coremap = local_coremap->next;
}
return pt_entry->pa ;
}
else{
paddr_t p = swap_in(pt_entry->offset);
pt_entry->state = PAGE_IN_MEMORY;
pt_entry->pa = p;
pt_entry_temp2->state = 1000;
return p;
}
}
pt_entry_temp = pt_entry ;
pt_entry = pt_entry->next ;
}
paddr_t paddr = user_page_alloc() ;
pt_entry_temp2->va = faultaddress;
pt_entry_temp2->pa = paddr ;
pt_entry_temp2->state = PAGE_IN_MEMORY ;
pt_entry_temp2->offset = -1;
pt_entry_temp2->next = NULL ;
if (pt_entry_temp != NULL)
{
pt_entry_temp->next = pt_entry_temp2 ;
}
else
{
curthread->t_addrspace->page_table = pt_entry_temp2 ;
}
return paddr ;
}
void zmq::pipe_t::set_head (uint64_t position_)
{
// This may cause the next write to succeed.
in_core_msg_cnt -= position_ - last_head_position;
last_head_position = position_;
// Transfer messages from the data dam into the main memory.
if (swapping && in_core_msg_cnt < (size_t) lwm)
swap_in ();
// If there's a gap notification waiting, push it into the queue.
if (delayed_gap && check_write ()) {
raw_message_t msg;
raw_message_init_notification (&msg, raw_message_t::gap_tag);
write (&msg);
delayed_gap = false;
}
}
void swap_out(uint32_t pid, uint16_t id_segmento, pagina_t* * pagina)
{
// ----Abro el archivo----
uint16_t id_pagina = (*pagina)->id;
//Convierte cada id a string y despues los concatena de 2 en 2
char *nombre_archivo=generar_nombre_archivo_swap(pid, id_segmento, id_pagina);
char* path;
path=concat_string("en_disco/",nombre_archivo);
path=concat_string(path,".txt");
free(nombre_archivo);
//crea un archivo y lo guarda en una carpeta interna.
//el nombre se compone de pid, idsegmento y id pagina
FILE* arch = fopen(path,"r");
// ----Le consigo un marco a la pagina----
marco_t* marco = buscar_marco_libre();
if(marco==NULL){
swap_in(pagina, id_segmento, pid);
}else{
(*pagina)->marco=marco->id;
}
//Ahora pagina es de su marco
(*pagina)->tiene_marco=true;
(*pagina)->en_disco=false;
//Ahora el marco es de su pagina
marco = buscar_marco_segun_id((*pagina)->marco);
marco->id_proceso=pid;
(*pagina)->marco=marco->id;
marco->ocupado=true;
fread(marco->datos,sizeof(char),256,arch);
// ----Finalizo----
remove(path);
free(path);
disminuyo_cantidad_archivos_swap();
loggear_trace("Va a memoria pagina %d del segmento %d del proceso %d en marco %d.",
(*pagina)->id, id_segmento, marco->id_proceso, marco->id);
}
void load_ob_from_swap(object_t * ob)
{
if (ob->swap_num == -1)
fatal("Loading not swapped object.\n");
debug(d_flag, ("Unswap object /%s (ref %d)", ob->name, ob->ref));
swap_in((char **) &ob->prog, ob->swap_num);
SET_TAG(ob->prog, TAG_PROGRAM);
/*
* to be relocated: program functions strings variable_names inherit
* argument_types type_start
*/
locate_in(ob->prog); /* relocate the internal pointers */
/* The reference count will already be 1 ! */
ob->flags &= ~O_SWAPPED;
num_swapped--;
total_prog_block_size += ob->prog->total_size;
total_num_prog_blocks += 1;
}
/*===========================================================================*
* main *
*===========================================================================*/
PUBLIC void main()
{
/* Main routine of the memory manager. */
int result, proc_nr;
struct mproc *rmp;
mm_init(); /* initialize memory manager tables */
/* This is MM's main loop- get work and do it, forever and forever. */
while (TRUE) {
get_work(); /* wait for an MM system call */
/* If the call number is valid, perform the call. */
if ((unsigned) mm_call >= NCALLS) {
result = ENOSYS;
} else {
result = (*call_vec[mm_call])();
}
/* Send the results back to the user to indicate completion. */
if (result != E_NO_MESSAGE) setreply(who, result);
swap_in(); /* maybe a process can be swapped in? */
/* Send out all pending reply messages, including the answer to
* the call just made above. The processes must not be swapped out.
*/
for (proc_nr = 0, rmp = mproc; proc_nr < NR_PROCS; proc_nr++, rmp++) {
if ((rmp->mp_flags & (REPLY | ONSWAP)) == REPLY) {
if (send(proc_nr, &rmp->mp_reply) != OK)
panic("MM can't reply to", proc_nr);
rmp->mp_flags &= ~REPLY;
}
}
}
}
static inline void do_swap_page(struct task_struct * tsk,
struct vm_area_struct * vma, unsigned long address,
pte_t * page_table, pte_t entry, int write_access)
{
pte_t page;
if (!vma->vm_ops || !vma->vm_ops->swapin) {
swap_in(tsk, vma, page_table, pte_val(entry), write_access);
flush_page_to_ram(pte_page(*page_table));
return;
}
page = vma->vm_ops->swapin(vma, address - vma->vm_start + vma->vm_offset, pte_val(entry));
if (pte_val(*page_table) != pte_val(entry)) {
free_page(pte_page(page));
return;
}
if (mem_map[MAP_NR(pte_page(page))].count > 1 && !(vma->vm_flags & VM_SHARED))
page = pte_wrprotect(page);
++vma->vm_mm->rss;
++tsk->maj_flt;
flush_page_to_ram(pte_page(page));
set_pte(page_table, page);
return;
}
void
sos_VMFaultHandler(seL4_CPtr reply_cap, seL4_Word fault_addr, seL4_Word fsr, bool is_code){
dprintf(3, "sos vmfault handler \n");
int err;
dprintf(3, "sos vmfault handler, getting as \n");
addrspace_t *as = proc_getas();
dprintf(3, "sos vmfault handler, gotten as \n");
if (as == NULL) {
dprintf(3, "app as is NULL\n");
/* Kernel is probably failed when bootstraping */
set_cur_proc(PROC_NULL);
cspace_free_slot(cur_cspace, reply_cap);
return;
}
region_t *reg;
/* Is this a segfault? */
if (_check_segfault(as, fault_addr, fsr, ®)) {
dprintf(3, "vmf: segfault\n");
proc_destroy(proc_get_id());
set_cur_proc(PROC_NULL);
cspace_free_slot(cur_cspace, reply_cap);
return;
}
/*
* If it comes here, this must be a valid address Therefore, this page is
* either swapped out has never been mapped in
*/
VMF_cont_t *cont = malloc(sizeof(VMF_cont_t));
if (cont == NULL) {
dprintf(3, "vmfault out of mem\n");
/* We cannot handle the fault but the process still can run
* There will be more faults coming though */
set_cur_proc(PROC_NULL);
seL4_MessageInfo_t reply = seL4_MessageInfo_new(0, 0, 0, 0);
seL4_Send(reply_cap, reply);
cspace_free_slot(cur_cspace, reply_cap);
return;
}
cont->reply_cap = reply_cap;
cont->as = as;
cont->vaddr = fault_addr;
cont->is_code = is_code;
cont->reg = reg;
cont->pid = proc_get_id();
/* Check if this page is an new, unmaped page or is it just swapped out */
if (sos_page_is_inuse(as, fault_addr)) {
if (sos_page_is_swapped(as, fault_addr)) {
dprintf(3, "vmf tries to swapin\n");
/* This page is swapped out, we need to swap it back in */
err = swap_in(cont->as, cont->reg->rights, cont->vaddr,
cont->is_code, _sos_VMFaultHandler_reply, cont);
if (err) {
_sos_VMFaultHandler_reply((void*)cont, err);
return;
}
return;
} else {
if (sos_page_is_locked(as, fault_addr)) {
dprintf(3, "vmf page is locked\n");
_sos_VMFaultHandler_reply((void*)cont, EFAULT);
return;
}
dprintf(3, "vmf second chance mapping page back in\n");
err = _set_page_reference(cont->as, cont->vaddr, cont->reg->rights);
_sos_VMFaultHandler_reply((void*)cont, err);
return;
}
} else {
/* This page has never been mapped, so do that and return */
dprintf(3, "vmf tries to map a page\n");
inc_proc_size_proc(cur_proc());
err = sos_page_map(proc_get_id(), as, fault_addr, reg->rights, _sos_VMFaultHandler_reply, (void*)cont, false);
if(err){
dec_proc_size_proc(cur_proc());
_sos_VMFaultHandler_reply((void*)cont, err);
}
return;
}
/* Otherwise, this is not handled */
dprintf(3, "vmf error at the end\n");
_sos_VMFaultHandler_reply((void*)cont, EFAULT);
return;
}
/* do_pgfault - interrupt handler to process the page fault execption
* @mm : the control struct for a set of vma using the same PDT
* @error_code : the error code recorded in trapframe->tf_err which is setted by x86 hardware
* @addr : the addr which causes a memory access exception, (the contents of the CR2 register)
*
* CALL GRAPH: trap--> trap_dispatch-->pgfault_handler-->do_pgfault
* The processor provides ucore's do_pgfault function with two items of information to aid in diagnosing
* the exception and recovering from it.
* (1) The contents of the CR2 register. The processor loads the CR2 register with the
* 32-bit linear address that generated the exception. The do_pgfault fun can
* use this address to locate the corresponding page directory and page-table
* entries.
* (2) An error code on the kernel stack. The error code for a page fault has a format different from
* that for other exceptions. The error code tells the exception handler three things:
* -- The P flag (bit 0) indicates whether the exception was due to a not-present page (0)
* or to either an access rights violation or the use of a reserved bit (1).
* -- The W/R flag (bit 1) indicates whether the memory access that caused the exception
* was a read (0) or write (1).
* -- The U/S flag (bit 2) indicates whether the processor was executing at user mode (1)
* or supervisor mode (0) at the time of the exception.
*/
int
do_pgfault(struct mm_struct *mm, uint32_t error_code, uintptr_t addr) {
int ret = -E_INVAL;
//try to find a vma which include addr
struct vma_struct *vma = find_vma(mm, addr);
pgfault_num++;
//If the addr is in the range of a mm's vma?
if (vma == NULL || vma->vm_start > addr) {
cprintf("not valid addr %x, and can not find it in vma\n", addr);
goto failed;
}
//check the error_code
switch (error_code & 3) {
default:
/* error code flag : default is 3 ( W/R=1, P=1): write, present */
case 2: /* error code flag : (W/R=1, P=0): write, not present */
if (!(vma->vm_flags & VM_WRITE)) {
cprintf("do_pgfault failed: error code flag = write AND not present, but the addr's vma cannot write\n");
goto failed;
}
break;
case 1: /* error code flag : (W/R=0, P=1): read, present */
cprintf("do_pgfault failed: error code flag = read AND present\n");
goto failed;
case 0: /* error code flag : (W/R=0, P=0): read, not present */
if (!(vma->vm_flags & (VM_READ | VM_EXEC))) {
cprintf("do_pgfault failed: error code flag = read AND not present, but the addr's vma cannot read or exec\n");
goto failed;
}
}
/* IF (write an existed addr ) OR
* (write an non_existed addr && addr is writable) OR
* (read an non_existed addr && addr is readable)
* THEN
* continue process
*/
uint32_t perm = PTE_U;
if (vma->vm_flags & VM_WRITE) {
perm |= PTE_W;
}
addr = ROUNDDOWN(addr, PGSIZE);
ret = -E_NO_MEM;
pte_t *ptep=NULL;
/*LAB3 EXERCISE 1: 2012012139
* Maybe you want help comment, BELOW comments can help you finish the code
*
* Some Useful MACROs and DEFINEs, you can use them in below implementation.
* MACROs or Functions:
* get_pte : get an pte and return the kernel virtual address of this pte for la
* if the PT contians this pte didn't exist, alloc a page for PT (notice the 3th parameter '1')
* pgdir_alloc_page : call alloc_page & page_insert functions to allocate a page size memory & setup
* an addr map pa<--->la with linear address la and the PDT pgdir
* DEFINES:
* VM_WRITE : If vma->vm_flags & VM_WRITE == 1/0, then the vma is writable/non writable
* PTE_W 0x002 // page table/directory entry flags bit : Writeable
* PTE_U 0x004 // page table/directory entry flags bit : User can access
* VARIABLES:
* mm->pgdir : the PDT of these vma
*
*/
#if 0
/*LAB3 EXERCISE 1: 2012012139*/
ptep = ??? //(1) try to find a pte, if pte's PT(Page Table) isn't existed, then create a PT.
if (*ptep == 0) {
//(2) if the phy addr isn't exist, then alloc a page & map the phy addr with logical addr
}
else {
/*LAB3 EXERCISE 2: 2012012139
* Now we think this pte is a swap entry, we should load data from disk to a page with phy addr,
* and map the phy addr with logical addr, trigger swap manager to record the access situation of this page.
*
* Some Useful MACROs and DEFINEs, you can use them in below implementation.
* MACROs or Functions:
* swap_in(mm, addr, &page) : alloc a memory page, then according to the swap entry in PTE for addr,
* find the addr of disk page, read the content of disk page into this memroy page
* page_insert ： build the map of phy addr of an Page with the linear addr la
* swap_map_swappable ： set the page swappable
*/
/*
* LAB5 CHALLENGE ( the implmentation Copy on Write)
There are 2 situlations when code comes here.
1) *ptep & PTE_P == 1, it means one process try to write a readonly page.
If the vma includes this addr is writable, then we can set the page writable by rewrite the *ptep.
This method could be used to implement the Copy on Write (COW) thchnology(a fast fork process method).
2) *ptep & PTE_P == 0 & but *ptep!=0, it means this pte is a swap entry.
We should add the LAB3's results here.
*/
if(swap_init_ok) {
struct Page *page=NULL;
//(1）According to the mm AND addr, try to load the content of right disk page
// into the memory which page managed.
//(2) According to the mm, addr AND page, setup the map of phy addr <---> logical addr
//(3) make the page swappable.
//(4) [NOTICE]: you myabe need to update your lab3's implementation for LAB5's normal execution.
}
else {
cprintf("no swap_init_ok but ptep is %x, failed\n",*ptep);
goto failed;
}
}
#endif
// try to find a pte, if pte's PT(Page Table) isn't existed, then create a PT.
// (notice the 3th parameter '1')
if ((ptep = get_pte(mm->pgdir, addr, 1)) == NULL) {
cprintf("get_pte in do_pgfault failed\n");
goto failed;
}
if (*ptep == 0) { // if the phy addr isn't exist, then alloc a page & map the phy addr with logical addr
if (pgdir_alloc_page(mm->pgdir, addr, perm) == NULL) {
cprintf("pgdir_alloc_page in do_pgfault failed\n");
goto failed;
}
}
else {
struct Page *page=NULL;
cprintf("do pgfault: ptep %x, pte %x\n",ptep, *ptep);
if (*ptep & PTE_P) {
//if process write to this existed readonly page (PTE_P means existed), then should be here now.
//we can implement the delayed memory space copy for fork child process (AKA copy on write, COW).
//we didn't implement now, we will do it in future.
panic("error write a non-writable pte");
//page = pte2page(*ptep);
} else {
// if this pte is a swap entry, then load data from disk to a page with phy addr
// and call page_insert to map the phy addr with logical addr
if(swap_init_ok) {
if ((ret = swap_in(mm, addr, &page)) != 0) {
cprintf("swap_in in do_pgfault failed\n");
goto failed;
}
}
else {
cprintf("no swap_init_ok but ptep is %x, failed\n",*ptep);
goto failed;
}
}
page_insert(mm->pgdir, page, addr, perm);
swap_map_swappable(mm, addr, page, 1);
page->pra_vaddr = addr;
}
ret = 0;
failed:
return ret;
}
int handle_user_pagefault(void)
{
phys_pagedir = active_process->mem.phys_pd;
cr2 = asm_get_cr2();
dpage = ADDR_TO_PAGE(cr2);
doffset = eip - (char*) PAGE_TO_ADDR(dpage);
dpde = dpage / MEMORY_PE_COUNT;
dpte = dpage % MEMORY_PE_COUNT;
eip = (void*) kernel_tasks.tss_for_active_thread.eip;
cpage = ADDR_TO_PAGE(eip);
coffset = eip - (char*) PAGE_TO_ADDR(cpage);
cpde = cpage / MEMORY_PE_COUNT;
cpte = cpage % MEMORY_PE_COUNT;
const char *panic_msg;
uint_t new_location;
page_entry_t *pd, *pt;
if (!(pd = temp_page_directory(phys_pagedir))) {
goto no_pd_got;
}
if (!pd[dpde].pagenum) {
goto no_pt_page;
}
if ((dpde >= KMEM_PDE_END) && !pd[dpde].user) {
printf("User process = %d, thread = %d\n", active_pid, active_tid);
printf("Trying to access address %p (page %d).\n", asm_get_cr2(), ADDR_TO_PAGE(asm_get_cr2()));
printf("(!pd[dpde].user)\n");
panic("Bug in memory handling!");
}
if (!pd[dpde].present) {
new_location = swap_in(phys_pagedir, pd[dpde].pagenum);
if (!new_location) {
goto no_pt_page_swapped;
}
pd[dpde].pagenum = new_location;
pd[dpde].present = 1;
}
if (!(pt = temp_page_table(pd[dpde].pagenum))) {
goto no_pt_got;
}
if (dpde && dpte && !pt[dpte].pagenum) {
goto no_cr2_page;
}
if (!pt[dpte].user) {
return user_tries_kernel();
}
if (dpde < KMEM_PDE_END) {
printf("User process = %d, thread = %d\n", active_pid, active_tid);
printf("Trying to access address %p (page %d).\n", asm_get_cr2(), ADDR_TO_PAGE(asm_get_cr2()));
printf("(dpde < KMEM_PDE_END) && pt[dpte].user)\n");
panic("Bug in memory handling!");
return user_tries_kernel();
}
if (!pt[dpte].present) {
new_location = swap_in(phys_pagedir, pt[dpte].pagenum);
if (!new_location) {
goto no_cr2_page_swapped;
}
pt[dpte].pagenum = new_location;
pt[dpte].present = 1;
}
return 0; // Ratkaistu. :)
no_pd_got:
panic_msg = "Page fault: failed getting PD from RAM!";
goto fail;
no_pt_page:
panic_msg = "Page fault; page missing from PD!";
goto fail;
no_pt_page_swapped:
panic_msg = "Page fault; failed swapping PT to RAM!";
goto fail;
no_pt_got:
panic_msg = "Page fault; failed getting PT from RAM!";
goto fail;
no_cr2_page:
panic_msg = "Page fault; page missing from PT!";
goto fail;
no_cr2_page_swapped:
panic_msg = "Page fault; failed swapping page to RAM!";
goto fail;
fail:
printf("Page Fault!\nThread %i, process %i\n", active_tid, active_pid);
printf("Trying to access address %p (page %d).\n", cr2, dpage);
printf("%s\n", panic_msg);
return -1;
}
int
as_copy(struct addrspace *old, struct addrspace **ret)
{
struct addrspace *newas;
newas = as_create();
if (newas==NULL) {
return ENOMEM;
}
// kprintf(" **** inside as copy **** \n");
// spinlock_acquire(newas->as_splock);
// spinlock_acquire(old->as_splock);
if(use_small_lock == true && swapping_started == true)
{
lock_acquire(newas->as_lock);
lock_acquire(old->as_lock);
}
else if(use_big_lock == true && swapping_started == true)
lock_acquire(as_lock);
struct as_region* r_old = old->as_region_list;
while(r_old != NULL)
{
struct as_region* r_new = (struct as_region*)kmalloc(sizeof(struct as_region));
if(r_new == NULL)
{
if(use_big_lock == true && swapping_started == true)
lock_release(as_lock);
else if(use_small_lock == true && swapping_started == true)
{
lock_release(old->as_lock);
lock_release(newas->as_lock);
}
//spinlock_release(old->as_splock);
//spinlock_release(newas->as_splock);
as_destroy(newas);
return ENOMEM;
}
r_new->region_base = r_old->region_base;
r_new->region_npages = r_old->region_npages;
r_new->can_read = r_old->can_read;
r_new->can_write = r_old->can_write;
r_new->can_execute = r_old->can_execute;
int ret = region_list_add_node(&newas->as_region_list,r_new);
if(ret == -1)
{
if(use_big_lock == true && swapping_started == true)
lock_release(as_lock);
else if(use_small_lock == true && swapping_started == true)
{
lock_release(old->as_lock);
lock_release(newas->as_lock);
}
// spinlock_release(old->as_splock);
// spinlock_release(newas->as_splock);
as_destroy(newas);
return ENOMEM;
}
r_old = r_old->next;
}
struct page_table_entry* p_old = old->as_page_list;
while(p_old != NULL)
{
struct page_table_entry* p_new = (struct page_table_entry*)kmalloc(sizeof(struct page_table_entry));
if(p_new == NULL)
{
if(use_big_lock == true && swapping_started == true)
lock_release(as_lock);
else if(use_small_lock == true && swapping_started == true)
{
lock_release(old->as_lock);
lock_release(newas->as_lock);
}
// spinlock_release(old->as_splock);
// spinlock_release(newas->as_splock);
as_destroy(newas);
return ENOMEM;
}
p_new->vaddr = p_old->vaddr;
p_new->swap_pos = -1;
KASSERT(p_old->page_state != SWAPPING);
while(p_old->page_state == SWAPPING)
{
thread_yield();
}
// if(!spinlock_do_i_hold)
// KASSERT(p_old->page_state != SWAPPING);
if(p_old->page_state == MAPPED)
{
if(use_page_lock == true && swapping_started == true)
lock_acquire(coremap[(p_old->paddr)/PAGE_SIZE].page_lock);
if(p_old->page_state == MAPPED)
{
paddr_t paddr = get_user_page(p_old->vaddr, false, newas);
KASSERT(p_old->page_state == MAPPED);
// int spl = splhigh();
if(use_small_lock == true && swapping_started == true)
{
if(lock_do_i_hold(newas->as_lock) == false)
lock_acquire(newas->as_lock);
if(lock_do_i_hold(old->as_lock) == false)
lock_acquire(newas->as_lock);
}
else if(use_big_lock == true && swapping_started == true)
{
if(lock_do_i_hold(as_lock) == false)
lock_acquire(as_lock);
}
if(paddr == 0)
{
if(use_big_lock == true && swapping_started == true)
lock_release(as_lock);
else if(use_small_lock == true && swapping_started == true)
{
lock_release(old->as_lock);
lock_release(newas->as_lock);
}
// spinlock_release(old->as_splock);
// spinlock_release(newas->as_splock);
as_destroy(newas);
return ENOMEM;
}
uint32_t old_index = p_old->paddr/PAGE_SIZE;
KASSERT(coremap[old_index].is_victim == false);
KASSERT(coremap[paddr/PAGE_SIZE].is_victim == false);
memmove((void*)PADDR_TO_KVADDR(paddr),
(const void *)PADDR_TO_KVADDR(p_old->paddr), //use this? or PADDR_TO_KVADDR like dumbvm does?. But why does dumbvm do that in the first place.
PAGE_SIZE); // i know why, cannot call functions on user memory addresses. So convert it into a kv address.
// the function will translate it into a physical address again and free it. ugly Hack. but no other way.
p_new->paddr = paddr;
p_new->page_state = MAPPED;
// splx(spl);
int ret = page_list_add_node(&newas->as_page_list,p_new);
if(ret == -1)
{
if(use_big_lock == true && swapping_started == true)
lock_release(as_lock);
else if(use_small_lock == true && swapping_started == true)
{
lock_release(old->as_lock);
lock_release(newas->as_lock);
}
// spinlock_release(old->as_splock);
// spinlock_release(newas->as_splock);
as_destroy(newas);
return ENOMEM;
}
if(use_page_lock == true && swapping_started == true)
{
if(lock_do_i_hold(coremap[paddr/PAGE_SIZE].page_lock) == true)
lock_release(coremap[paddr/PAGE_SIZE].page_lock);
if(lock_do_i_hold(coremap[(p_old->paddr/PAGE_SIZE)].page_lock) == true)
lock_release(coremap[(p_old->paddr/PAGE_SIZE)].page_lock);
}
}
}
if(p_old->page_state == SWAPPED)
{
// this page is in disk, so we need to create a copy of that page somewhere in disk and then update the page table entry of the new process.
// going with the disk->memory->disk approach suggested in a recitation video by jinghao shi.
// Allocate a buffer at vm_bootstrap of size 4k (1 page). Use this buffer to temporarily copy data from disk to here and then to disk again
// then clear the buffer. This buffer is a shared resource, so we need a lock around it.
// kprintf("in as_copy swap code \n");
// spinlock_release(old->as_splock);
// spinlock_release(newas->as_splock);
swap_in(p_old->vaddr,old,copy_buffer_vaddr, p_old->swap_pos);
// kprintf("completed swap in \n");
int pos = mark_swap_pos(p_new->vaddr, newas);
KASSERT(pos != -1);
int err = write_to_disk(KVADDR_TO_PADDR(copy_buffer_vaddr)/PAGE_SIZE, pos);
// kprintf("completed writing to disk \n");
KASSERT(err == 0);
// spinlock_acquire(newas->as_splock);
// spinlock_acquire(old->as_splock);
// as_zero_region(KVADDR_TO_PADDR(copy_buffer_vaddr),1);
p_new->page_state = SWAPPED;
p_new->swap_pos = pos;
p_new->paddr = 0;
if(use_page_lock == true && swapping_started == true)
{
if(lock_do_i_hold(coremap[(p_old->paddr/PAGE_SIZE)].page_lock) == true)
lock_release(coremap[(p_old->paddr/PAGE_SIZE)].page_lock);
}
}
p_old = p_old->next;
}
newas->as_heap_start = old->as_heap_start;
newas->as_heap_end = old->as_heap_end;
*ret = newas;
if(use_big_lock == true && swapping_started == true)
lock_release(as_lock);
else if(use_small_lock == true && swapping_started == true)
{
lock_release(old->as_lock);
lock_release(newas->as_lock);
}
// kprintf("exiting as copy \n");
// spinlock_release(old->as_splock);
// spinlock_release(newas->as_splock);
return 0;
}
/* do_pgfault - interrupt handler to process the page fault execption
* @mm : the control struct for a set of vma using the same PDT
* @error_code : the error code recorded in trapframe->tf_err which is setted by x86 hardware
* @addr : the addr which causes a memory access exception, (the contents of the CR2 register)
*
* CALL GRAPH: trap--> trap_dispatch-->pgfault_handler-->do_pgfault
* The processor provides ucore's do_pgfault function with two items of information to aid in diagnosing
* the exception and recovering from it.
* (1) The contents of the CR2 register. The processor loads the CR2 register with the
* 32-bit linear address that generated the exception. The do_pgfault fun can
* use this address to locate the corresponding page directory and page-table
* entries.
* (2) An error code on the kernel stack. The error code for a page fault has a format different from
* that for other exceptions. The error code tells the exception handler three things:
* -- The P flag (bit 0) indicates whether the exception was due to a not-present page (0)
* or to either an access rights violation or the use of a reserved bit (1).
* -- The W/R flag (bit 1) indicates whether the memory access that caused the exception
* was a read (0) or write (1).
* -- The U/S flag (bit 2) indicates whether the processor was executing at user mode (1)
* or supervisor mode (0) at the time of the exception.
*/
int
do_pgfault(struct mm_struct *mm, uint32_t error_code, uintptr_t addr) {
int ret = -E_INVAL;
//try to find a vma which include addr
struct vma_struct *vma = find_vma(mm, addr);
pgfault_num++;
//If the addr is in the range of a mm's vma?
if (vma == NULL || vma->vm_start > addr) {
cprintf("not valid addr %x, and can not find it in vma\n", addr);
goto failed;
}
//check the error_code
switch (error_code & 3) {
default:
/* error code flag : default is 3 ( W/R=1, P=1): write, present */
case 2: /* error code flag : (W/R=1, P=0): write, not present */
if (!(vma->vm_flags & VM_WRITE)) {
cprintf("do_pgfault failed: error code flag = write AND not present, but the addr's vma cannot write\n");
goto failed;
}
break;
case 1: /* error code flag : (W/R=0, P=1): read, present */
cprintf("do_pgfault failed: error code flag = read AND present\n");
goto failed;
case 0: /* error code flag : (W/R=0, P=0): read, not present */
if (!(vma->vm_flags & (VM_READ | VM_EXEC))) {
cprintf("do_pgfault failed: error code flag = read AND not present, but the addr's vma cannot read or exec\n");
goto failed;
}
}
/* IF (write an existed addr ) OR
* (write an non_existed addr && addr is writable) OR
* (read an non_existed addr && addr is readable)
* THEN
* continue process
*/
uint32_t perm = PTE_U;
if (vma->vm_flags & VM_WRITE) {
perm |= PTE_W;
}
addr = ROUNDDOWN(addr, PGSIZE);
ret = -E_NO_MEM;
pte_t *ptep=NULL;
/*LAB3 EXERCISE 1: YOUR CODE
* Maybe you want help comment, BELOW comments can help you finish the code
*
* Some Useful MACROs and DEFINEs, you can use them in below implementation.
* MACROs or Functions:
* get_pte : get an pte and return the kernel virtual address of this pte for la
* if the PT contians this pte didn't exist, alloc a page for PT (notice the 3th parameter '1')
* pgdir_alloc_page : call alloc_page & page_insert functions to allocate a page size memory & setup
* an addr map pa<--->la with linear address la and the PDT pgdir
* DEFINES:
* VM_WRITE : If vma->vm_flags & VM_WRITE == 1/0, then the vma is writable/non writable
* PTE_W 0x002 // page table/directory entry flags bit : Writeable
* PTE_U 0x004 // page table/directory entry flags bit : User can access
* VARIABLES:
* mm->pgdir : the PDT of these vma
*
*/
//#if 0
/*LAB3 EXERCISE 1: YOUR CODE*/
ptep = get_pte(mm->pgdir, addr, 1); //(1) try to find a pte, if pte's PT(Page Table) isn't existed, then create a PT.
if (ptep == NULL) {
cprintf("get_pte failed in do_pgfault \n");
goto failed;
}
//(2) if the phy addr isn't exist, then alloc a page & map the phy addr with logical addr
if (*ptep == 0) {
if (pgdir_alloc_page(mm->pgdir, addr, perm) == NULL) {
cprintf("pgdir_alloc_page failed in do_pgfault \n");
goto failed;
}
}
else {
/*LAB3 EXERCISE 2: YOUR CODE
* Now we think this pte is a swap entry, we should load data from disk to a page with phy addr,
* and map the phy addr with logical addr, trigger swap manager to record the access situation of this page.
*
* Some Useful MACROs and DEFINEs, you can use them in below implementation.
* MACROs or Functions:
* swap_in(mm, addr, &page) : alloc a memory page, then according to the swap entry in PTE for addr,
* find the addr of disk page, read the content of disk page into this memroy page
* page_insert ： build the map of phy addr of an Page with the linear addr la
* swap_map_swappable ： set the page swappable
*/
if(swap_init_ok) {
struct Page *page=NULL;
//(1）According to the mm AND addr, try to load the content of right disk page
// into the memory which page managed.
int r;
r = swap_in(mm, addr, &page);
if (r != 0) {
cprintf("swap_in failed in do_pgfault \n");
goto failed;
}
//(2) According to the mm, addr AND page, setup the map of phy addr <---> logical addr
page_insert(mm->pgdir, page, addr, perm);
//(3) make the page swappable.
swap_map_swappable(mm, addr, page, 1);
page->pra_vaddr = addr;
}
else {
cprintf("no swap_init_ok but ptep is %x, failed\n",*ptep);
goto failed;
}
}
//#endif
ret = 0;
failed:
return ret;
}
/* do_pgfault - interrupt handler to process the page fault execption
* @mm : the control struct for a set of vma using the same PDT
* @error_code : the error code recorded in trapframe->tf_err which is setted by x86 hardware
* @addr : the addr which causes a memory access exception, (the contents of the CR2 register)
*
* CALL GRAPH: trap--> trap_dispatch-->pgfault_handler-->do_pgfault
* The processor provides ucore's do_pgfault function with two items of information to aid in diagnosing
* the exception and recovering from it.
* (1) The contents of the CR2 register. The processor loads the CR2 register with the
* 32-bit linear address that generated the exception. The do_pgfault fun can
* use this address to locate the corresponding page directory and page-table
* entries.
* (2) An error code on the kernel stack. The error code for a page fault has a format different from
* that for other exceptions. The error code tells the exception handler three things:
* -- The P flag (bit 0) indicates whether the exception was due to a not-present page (0)
* or to either an access rights violation or the use of a reserved bit (1).
* -- The W/R flag (bit 1) indicates whether the memory access that caused the exception
* was a read (0) or write (1).
* -- The U/S flag (bit 2) indicates whether the processor was executing at user mode (1)
* or supervisor mode (0) at the time of the exception.
*/
int vm_pgfault_handler(ProcVM *mm, uint32_t error_code, uintptr_t addr)
{
int ret = -EINVAL;
// Try to find a vma which include addr.
ProcVMA *vma = vm_find_vma(mm, addr);
++vm_pgfault_count;
//If the addr is in the range of a mm's vma?
if (vma == NULL || vma->vm_start > addr) {
printf("[vmm] pgfault_handler: not valid vma 0x%08x\n", addr);
goto failed;
}
//check the error_code
switch (error_code & 3) {
/* error code flag : default is 3 (W/R=1, P=1): write, present */
default:
/* error code flag : (W/R=1, P=0): write, not present */
case 2:
if (!(vma->vm_flags & VM_WRITE)) {
printf("[vmm] pgfault_handler: error code flag = write AND not present,"
" but the addr's vma cannot write\n");
goto failed;
}
break;
/* error code flag : (W/R=0, P=1): read, present */
case 1:
printf("[vmm] pgfault_handler: error code flag = read AND present.\n");
goto failed;
/* error code flag : (W/R=0, P=0): read, not present */
case 0:
if (!(vma->vm_flags & (VM_READ | VM_EXEC))) {
printf("[vmm] pgfault_handler: error code flag = read AND not present,"
" but the addr's vma cannot read or exec.\n");
goto failed;
}
break;
}
/* IF (write an existed addr ) OR
* (write an non_existed addr && addr is writable) OR
* (read an non_existed addr && addr is readable)
* THEN
* continue process
*/
uint32_t perm = PTE_U;
if (vma->vm_flags & VM_WRITE) {
perm |= PTE_W;
}
addr = K_ROUND_DOWN(addr, PGSIZE); // Round to page margin.
ret = -ENOMEM;
// mm should be associated with particular process, so mm->pgdir here.
pte_t *ptep = NULL;
ptep = get_pte(mm->pgdir, addr, 1);
if (ptep == NULL) {
printf("[vmm] Cannot create page table entry for address 0x%08x\n", addr);
goto failed;
}
// Page table entry does not exist, which indicates that this page is never
// created. So just create a new one.
Page* page;
if (*ptep == 0) {
if ((page = pgdir_alloc_page(mm->pgdir, addr, perm)) == NULL) {
printf("[vmm] Cannot create page for address 0x%08x\n", addr);
goto failed;
}
}
// Otherwise, the page was ever created, but is in swap at the moment.
// So we need to load data from disk into the memory.
else {
if ((*ptep & PTE_P) == 0) {
panic("[vmm] pgfault_handler: Page seems to be on swap, while swap is "
"not enabled.");
#if 0
// Check whether swap has been inited.
if (!swap_init_ok) {
cprintf("Swap is never initialized but a page [pte=%08x] on swap is requested.\n", *ptep);
goto failed;
}
// Swep in the required page.
if (swap_in(mm, addr, &page) != 0) {
cprintf("Cannot swap in page 0x%08x.\n", *ptep);
goto failed;
}
page_insert(mm->pgdir, page, addr, perm);
// Register the new page to vmm manager.
swap_map_swappable(mm, addr, page, 1);
#endif
}
}
ret = 0;
failed:
return ret;
}
