static int fetch_file_page(struct filemap *fm, void *addr) {
struct file *filp;
unsigned long pfn;
unsigned long pos;
int rc;
filp = (struct file *) olock(fm->file, OBJECT_FILE);
if (!filp) return -EBADF;
pfn = alloc_pageframe('FMAP');
if (pfn == 0xFFFFFFFF) {
orel(filp);
return -ENOMEM;
}
map_page(addr, pfn, PT_WRITABLE | PT_PRESENT);
pos = (char *) addr - fm->addr;
rc = pread(filp, addr, PAGESIZE, fm->offset + pos);
if (rc < 0) {
orel(filp);
unmap_page(addr);
free_pageframe(pfn);
return rc;
}
pfdb[pfn].owner = fm->self;
map_page(addr, pfn, fm->protect | PT_PRESENT);
orel(filp);
return 0;
}
static int expand_htab() {
unsigned long pfn;
handle_t h;
if (htabsize == HTABSIZE / sizeof(struct object *)) return -ENFILE;
pfn = alloc_pageframe('HTAB');
map_page(htab + htabsize, pfn, PT_WRITABLE | PT_PRESENT);
for (h = htabsize + HANDLES_PER_PAGE - 1; h >= htabsize; h--) {
htab[h] = hfreelist;
hfreelist = h;
}
htabsize += HANDLES_PER_PAGE;
return 0;
}
int guard_page_handler(void *addr) {
unsigned long pfn;
struct thread *t = self();
if (!t->tib) return -EFAULT;
if (addr < t->tib->stacklimit || addr >= t->tib->stacktop) return -EFAULT;
if (t->tib->stacklimit <= t->tib->stackbase) return -EFAULT;
pfn = alloc_pageframe('STK');
if (pfn == 0xFFFFFFFF) return -ENOMEM;
t->tib->stacklimit = (char *) t->tib->stacklimit - PAGESIZE;
map_page(t->tib->stacklimit, pfn, PT_GUARD | PT_WRITABLE | PT_PRESENT);
memset(t->tib->stacklimit, 0, PAGESIZE);
return 0;
}
void map_page(void *vaddr, unsigned long pfn, unsigned long flags) {
// Allocate page table if not already done
if ((GET_PDE(vaddr) & PT_PRESENT) == 0) {
unsigned long pdfn;
pdfn = alloc_pageframe('PTAB');
if (USERSPACE(vaddr)) {
SET_PDE(vaddr, PTOB(pdfn) | PT_PRESENT | PT_WRITABLE | PT_USER);
} else {
SET_PDE(vaddr, PTOB(pdfn) | PT_PRESENT | PT_WRITABLE);
}
memset(ptab + PDEIDX(vaddr) * PTES_PER_PAGE, 0, PAGESIZE);
register_page_table(pdfn);
}
// Map page frame into address space
SET_PTE(vaddr, PTOB(pfn) | flags);
}
void *vmalloc(void *addr, unsigned long size, int type, int protect, unsigned long tag, int *rc) {
int pages = PAGES(size);
unsigned long flags = pte_flags_from_protect(protect);
int i;
if (rc) *rc = 0;
if (size == 0) {
if (rc) *rc = -EINVAL;
return NULL;
}
if ((type & MEM_COMMIT) != 0 && flags == 0xFFFFFFFF) {
if (rc) *rc = -EINVAL;
return NULL;
}
addr = (void *) PAGEADDR(addr);
if (!addr && (type & MEM_COMMIT) != 0) type |= MEM_RESERVE;
if (!tag) tag = 'VM';
if (type & MEM_RESERVE) {
if (addr == NULL) {
if (type & MEM_ALIGN64K) {
addr = (void *) PTOB(rmap_alloc_align(vmap, pages, 64 * 1024 / PAGESIZE));
} else {
addr = (void *) PTOB(rmap_alloc(vmap, pages));
}
if (addr == NULL) {
if (rc) *rc = -ENOMEM;
return NULL;
}
} else {
if (rmap_reserve(vmap, BTOP(addr), pages)) {
if (rc) *rc = -ENOMEM;
return NULL;
}
}
} else {
if (!valid_range(addr, size)) {
if (rc) *rc = -EFAULT;
return NULL;
}
}
if (type & MEM_COMMIT) {
char *vaddr;
unsigned long pfn;
vaddr = (char *) addr;
for (i = 0; i < pages; i++) {
if (page_mapped(vaddr)) {
set_page_flags(vaddr, flags | PT_PRESENT);
} else {
pfn = alloc_pageframe(tag);
if (pfn == 0xFFFFFFFF) {
if (rc) *rc = -ENOMEM;
return NULL;
}
map_page(vaddr, pfn, flags | PT_PRESENT);
memset(vaddr, 0, PAGESIZE);
}
vaddr += PAGESIZE;
}
}
return addr;
}
