in mm/uaccess.c [22:37]
__kernel_size_t __clear_user_hexagon(void __user *dest, unsigned long count)
{
long uncleared;
while (count > PAGE_SIZE) {
uncleared = raw_copy_to_user(dest, &empty_zero_page, PAGE_SIZE);
if (uncleared)
return count - (PAGE_SIZE - uncleared);
count -= PAGE_SIZE;
dest += PAGE_SIZE;
}
if (count)
count = raw_copy_to_user(dest, &empty_zero_page, count);
return count;
}