static kstatus_t retain_helper(struct _physicalMemoryManager* self, unsigned nbr_page,
IPhysicalPage* out_pages, BOOL try_to_search_in_free_page_list)
{
for (unsigned i = 0; i < nbr_page; i++)
{
IPhysicalPage page_to_give = 0x0;
/* First try to get from free list
*/
if (try_to_search_in_free_page_list)
page_to_give = SINGLY_LINKED_LIST_FIRST_VALUE(self->_freePageList);
if (page_to_give) /* There is a free page available */
{
SINGLY_LINKED_LIST_POP(self->_freePageList); /* Remove from free page list */
}
else /* Free page list is empty */
{
/* Move the kernel extended memory top address
*/
ASSERT(self->_extendedMemoryTop > self->_usedExtendedMemoryTop, "Extended memory full");
page_to_give = physical_page_alloc(); /* Alloc a new physical page object */
page_to_give->initWithPhysicalAddress(page_to_give, self->_usedExtendedMemoryTop); /* Associate top address with page */
self->_usedExtendedMemoryTop += PAGESIZE;
}
ASSERT(page_to_give != 0x0, "page_to_give is null");
/* Insert in caller output
*/
out_pages[i] = page_to_give;
}
return KS_SUCCESS;
}
// copyseg(p, ph, src)
// Load an ELF segment at virtual address `ph->p_va` in process `p`. Copies
// `[src, src + ph->p_filesz)` to `dst`, then clears
// `[ph->p_va + ph->p_filesz, ph->p_va + ph->p_memsz)` to 0.
// Calls `physical_page_alloc` to allocate pages and `virtual_memory_map`
// to map them in `p->p_pagetable`. Returns 0 on success and -1 on failure.
static int copyseg(proc* p, const elf_program* ph, const uint8_t* src) {
uintptr_t va = (uintptr_t) ph->p_va;
uintptr_t end_file = va + ph->p_filesz, end_mem = va + ph->p_memsz;
va &= ~(PAGESIZE - 1); // round to page boundary
// allocate memory
for (uintptr_t page_va = va; page_va < end_mem; page_va += PAGESIZE) {
if (physical_page_alloc(page_va, p->p_pid) < 0)
return -1;
virtual_memory_map(p->p_pagetable, page_va, page_va,
PAGESIZE, PTE_P|PTE_W|PTE_U);
}
// ensure new memory mappings are active
lcr3((uintptr_t) p->p_pagetable);
memcpy((uint8_t*) va, src, end_file - va);
memset((uint8_t*) end_file, 0, end_mem - end_file);
return 0;
}
