// do_shmem - create a share memory with addr, len, flags(VM_READ/M_WRITE/VM_STACK)
int do_shmem(uintptr_t * addr_store, size_t len, uint32_t mmap_flags)
{
struct mm_struct *mm = current->mm;
if (mm == NULL) {
panic("kernel thread call mmap!!.\n");
}
if (addr_store == NULL || len == 0) {
return -E_INVAL;
}
int ret = -E_INVAL;
uintptr_t addr;
lock_mm(mm);
if (!copy_from_user(mm, &addr, addr_store, sizeof(uintptr_t), 1)) {
goto out_unlock;
}
uintptr_t start = ROUNDDOWN(addr, PGSIZE), end =
ROUNDUP(addr + len, PGSIZE);
addr = start, len = end - start;
uint32_t vm_flags = VM_READ;
if (mmap_flags & MMAP_WRITE)
vm_flags |= VM_WRITE;
if (mmap_flags & MMAP_STACK)
vm_flags |= VM_STACK;
ret = -E_NO_MEM;
if (addr == 0) {
if ((addr = get_unmapped_area(mm, len)) == 0) {
goto out_unlock;
}
}
struct shmem_struct *shmem;
if ((shmem = shmem_create(len)) == NULL) {
goto out_unlock;
}
if ((ret = mm_map_shmem(mm, addr, vm_flags, shmem, NULL)) != 0) {
assert(shmem_ref(shmem) == 0);
shmem_destroy(shmem);
goto out_unlock;
}
copy_to_user(mm, addr_store, &addr, sizeof(uintptr_t));
out_unlock:
unlock_mm(mm);
return ret;
}
static void
check_mm_shm_swap(void) {
size_t nr_free_pages_store = nr_free_pages();
size_t slab_allocated_store = slab_allocated();
int ret, i;
for (i = 0; i < max_swap_offset; i ++) {
assert(mem_map[i] == SWAP_UNUSED);
}
extern struct mm_struct *check_mm_struct;
assert(check_mm_struct == NULL);
struct mm_struct *mm0 = mm_create(), *mm1;
assert(mm0 != NULL && list_empty(&(mm0->mmap_list)));
struct Page *page = alloc_page();
assert(page != NULL);
pde_t *pgdir = page2kva(page);
memcpy(pgdir, boot_pgdir, PGSIZE);
pgdir[PDX(VPT)] = PADDR(pgdir) | PTE_P | PTE_W;
mm0->pgdir = pgdir;
check_mm_struct = mm0;
lcr3(PADDR(mm0->pgdir));
uint32_t vm_flags = VM_WRITE | VM_READ;
uintptr_t addr0, addr1;
addr0 = 0;
do {
if ((ret = mm_map(mm0, addr0, PTSIZE * 4, vm_flags, NULL)) == 0) {
break;
}
addr0 += PTSIZE;
} while (addr0 != 0);
assert(ret == 0 && addr0 != 0 && mm0->map_count == 1);
ret = mm_unmap(mm0, addr0, PTSIZE * 4);
assert(ret == 0 && mm0->map_count == 0);
struct shmem_struct *shmem = shmem_create(PTSIZE * 2);
assert(shmem != NULL && shmem_ref(shmem) == 0);
// step1: check share memory
struct vma_struct *vma;
addr1 = addr0 + PTSIZE * 2;
ret = mm_map_shmem(mm0, addr0, vm_flags, shmem, &vma);
assert(ret == 0);
assert((vma->vm_flags & VM_SHARE) && vma->shmem == shmem && shmem_ref(shmem) == 1);
ret = mm_map_shmem(mm0, addr1, vm_flags, shmem, &vma);
assert(ret == 0);
assert((vma->vm_flags & VM_SHARE) && vma->shmem == shmem && shmem_ref(shmem) == 2);
// page fault
for (i = 0; i < 4; i ++) {
*(char *)(addr0 + i * PGSIZE) = (char)(i * i);
}
for (i = 0; i < 4; i ++) {
assert(*(char *)(addr1 + i * PGSIZE) == (char)(i * i));
}
for (i = 0; i < 4; i ++) {
*(char *)(addr1 + i * PGSIZE) = (char)(- i * i);
}
for (i = 0; i < 4; i ++) {
assert(*(char *)(addr1 + i * PGSIZE) == (char)(- i * i));
}
// check swap
ret = swap_out_mm(mm0, 8) + swap_out_mm(mm0, 8);
assert(ret == 8 && nr_active_pages == 4 && nr_inactive_pages == 0);
refill_inactive_scan();
assert(nr_active_pages == 0 && nr_inactive_pages == 4);
// write & read again
memset((void *)addr0, 0x77, PGSIZE);
for (i = 0; i < PGSIZE; i ++) {
assert(*(char *)(addr1 + i) == (char)0x77);
}
// check unmap
ret = mm_unmap(mm0, addr1, PGSIZE * 4);
assert(ret == 0);
addr0 += 4 * PGSIZE, addr1 += 4 * PGSIZE;
*(char *)(addr0) = (char)(0xDC);
assert(*(char *)(addr1) == (char)(0xDC));
*(char *)(addr1 + PTSIZE) = (char)(0xDC);
assert(*(char *)(addr0 + PTSIZE) == (char)(0xDC));
cprintf("check_mm_shm_swap: step1, share memory ok.\n");
// setup mm1
mm1 = mm_create();
assert(mm1 != NULL);
page = alloc_page();
assert(page != NULL);
pgdir = page2kva(page);
memcpy(pgdir, boot_pgdir, PGSIZE);
pgdir[PDX(VPT)] = PADDR(pgdir) | PTE_P | PTE_W;
mm1->pgdir = pgdir;
ret = dup_mmap(mm1, mm0);
assert(ret == 0 && shmem_ref(shmem) == 4);
// switch to mm1
check_mm_struct = mm1;
lcr3(PADDR(mm1->pgdir));
for (i = 0; i < 4; i ++) {
*(char *)(addr0 + i * PGSIZE) = (char)(0x57 + i);
}
for (i = 0; i < 4; i ++) {
assert(*(char *)(addr1 + i * PGSIZE) == (char)(0x57 + i));
}
check_mm_struct = mm0;
lcr3(PADDR(mm0->pgdir));
for (i = 0; i < 4; i ++) {
assert(*(char *)(addr0 + i * PGSIZE) == (char)(0x57 + i));
assert(*(char *)(addr1 + i * PGSIZE) == (char)(0x57 + i));
}
swap_out_mm(mm1, 4);
exit_mmap(mm1);
free_page(kva2page(mm1->pgdir));
mm_destroy(mm1);
assert(shmem_ref(shmem) == 2);
cprintf("check_mm_shm_swap: step2, dup_mmap ok.\n");
// free memory
check_mm_struct = NULL;
lcr3(boot_cr3);
exit_mmap(mm0);
free_page(kva2page(mm0->pgdir));
mm_destroy(mm0);
refill_inactive_scan();
page_launder();
for (i = 0; i < max_swap_offset; i ++) {
assert(mem_map[i] == SWAP_UNUSED);
}
assert(nr_free_pages_store == nr_free_pages());
assert(slab_allocated_store == slab_allocated());
cprintf("check_mm_shm_swap() succeeded.\n");
}