On 04/07/17 at 08:05am, David Howells wrote: > Dave Young <dyo...@redhat.com> wrote: > > > > > This option allows userspace to pass the RSDP address to the kernel, > > > > which > > > > makes it possible for a user to circumvent any restrictions imposed on > > > > loading modules. Ignore the option when the kernel is locked down. > > > > > > I'm not really sure here. > > > > > > What exactly is the mechanism? > > > > Actually this acpi_rsdp param is created for EFI kexec reboot in old > > days when we had not supported persistent efi vm space across kexec > > reboot. At that time kexec reboot runs as noefi mode, it can not find > > the acpi root table thus kernel will hang early. > > > > Now kexec can support EFI boot so this param is not necessary for most > > user unless they still use efi=old_map. > > Is this patch now unnecessary?
I think it is still necessary because the acpi_rsdp kernel param is still a valid paramater and one can still pass a pointer to be recognized as acpi root pointer. Maybe "imposed on loading modules" is not clear which can be dropped. Thanks Dave
