The 07/31/2023 14:43, Mark Brown wrote: > +SYSCALL_DEFINE3(map_shadow_stack, unsigned long, addr, unsigned long, size, unsigned int, flags) > +{ > + unsigned long alloc_size; > + unsigned long __user *cap_ptr; > + unsigned long cap_val; > + int ret; > + > + if (!system_supports_gcs()) > + return -EOPNOTSUPP; > + > + if (flags) > + return -EINVAL; > + > + if (addr % 16) > + return -EINVAL; mmap addr must be page aligned (and there is no align req on size). i'd expect similar api here. > + > + if (size == 16 || size % 16) > + return -EINVAL; why %16 and not %8 ?