/* Kontrollera alla adresser från och med start till och med den
* adress som först innehåller ett noll-tecken, `\0'. (C-strängar
* lagras på detta sätt.) */
bool verify_variable_length(char* buf)
{
/*if(pagedir_get_page(thread_current()->pagedir, (buf)) == NULL)
return false;*/
int i=0;
unsigned pg_last = pg_no(buf);
while(true)
{
if(i==0 || pg_no(buf+i) != pg_last)
{
if(pagedir_get_page(thread_current()->pagedir, (buf+i)) == NULL)
return false;
if(is_end_of_string(buf+i))
break;
}
else if(pg_no(buf+i) == pg_last)
{
if(is_end_of_string(buf+i))
break;
}
pg_last = pg_no(buf+i);
++i;
}
return true;
}
/* Frees the PAGE_CNT pages starting at PAGES. */
void
palloc_free_multiple (void *pages, size_t page_cnt)
{
struct pool *pool;
size_t page_idx;
ASSERT (pg_ofs (pages) == 0);
if (pages == NULL || page_cnt == 0)
return;
if (page_from_pool (&kernel_pool, pages))
pool = &kernel_pool;
else if (page_from_pool (&user_pool, pages))
pool = &user_pool;
else
NOT_REACHED ();
page_idx = pg_no (pages) - pg_no (pool->base);
#ifndef NDEBUG
memset (pages, 0xcc, PGSIZE * page_cnt);
#endif
ASSERT (bitmap_all (pool->used_map, page_idx, page_cnt));
bitmap_set_multiple (pool->used_map, page_idx, page_cnt, false);
}
/* Returns true if PAGE was allocated from POOL,
false otherwise. */
static bool
page_from_pool (const struct pool *pool, void *page)
{
size_t page_no = pg_no (page);
size_t start_page = pg_no (pool->base);
size_t end_page = start_page + bitmap_size (pool->used_map);
return page_no >= start_page && page_no < end_page;
}
/* Fill a frametable_entry with data
*/
void
frametable_entry_create(struct frametable_entry* fte,
struct pagetable_entry* pte,
tid_t tid,
void *virt_address,
bool pin) {
fte->pte = pte;
fte->tid = tid;
fte->virt_address = pg_no(virt_address);
fte->pin = pin;
}
/*
* Converts a pointer to any address into a number from
* 0 to USER_PAGES-1 (the amount of pages in the userpool)
* This can be used to as an index to access the frames
* within the frame table.
*/
static uint32_t
page_to_pagenum(void *page) {
// pages are consecutive and nothing can be before the base
ASSERT(page >= frametable.base_addr);
// remove offset within frame
page = pg_round_down(page);
// address shift relative to base addr
page -= (uintptr_t) frametable.base_addr;
return pg_no(page);
}
/* Kontrollera alla adresser från och med start till och inte med
* (start+length). */
bool verify_fix_length(void* buf, int length)
{
/*if(buf == NULL)
return false;*/
/*if(pagedir_get_page(thread_current()->pagedir,buf) == NULL)
return false;*/
int i=0;
if(pagedir_get_page(thread_current()->pagedir, (buf)) == NULL)
return false;
unsigned pg_last = pg_no(buf);
for(i=0;i<length;++i)
{
if(pg_no(buf) != pg_last)
{
if(pagedir_get_page(thread_current()->pagedir, (buf)) == NULL)
return false;
}
pg_last = pg_no(buf);
buf = (char*)buf + 1;
}
return true;
}
/* Obtains a single free page and returns its kernel virtual
address.
If PAL_USER is set, the page is obtained from the user pool,
otherwise from the kernel pool. If PAL_ZERO is set in FLAGS,
then the page is filled with zeros. If no pages are
available, returns a null pointer, unless PAL_ASSERT is set in
FLAGS, in which case the kernel panics. */
void *
palloc_page (enum palloc_flags flags, void * upage, bool writable)
{
bool success = false;
if(!(flags & PAL_USER))
PANIC ("This function cannot be called without PAL_USER flag set\n");
struct pool *pool = &frame_table.frame_pool;
size_t page_idx;
// empty page, and set to used
lock_acquire (&pool->lock);
page_idx = bitmap_scan_and_flip (pool->used_map, 0, 1, false);
lock_release (&pool->lock);
/* sets the members of cur_frame struct after is it allocated */
struct frame_entry * cur_frame;
cur_frame = frame_table.frames + page_idx;
cur_frame->pid = thread_current()->tid;
cur_frame->page_num = pg_no(upage);
cur_frame->reference = true;
cur_frame->dirty = false;
cur_frame->resident = true;
success = install_page (upage, cur_frame->kpage, writable);
if(DBG)printf("success after in mapping upage %p to kpage %p in palloc page = %d\n", upage, cur_frame->kpage, success);
// execute flags
if(!success)
{
if (flags & PAL_ASSERT)
PANIC ("palloc_get: out of pages"); // change this?
return NULL;
}
else if (flags & PAL_ZERO)
memset (upage, 0, PGSIZE);
return cur_frame->kpage;
}
/* Validates all pointers between start and end in a few page table
inspections as possible. Same notes as validate_byte(). */
static void validate_range(void *start, void *end) {
int i;
for(i = pg_no(end) - pg_no(start); i >= 0; i--)
validate_byte(start + (PGSIZE * i));
}