On 05/27/14 at 02:36pm, Fleming, Matt wrote: > On 27 May 2014 04:00, Dave Young <dyoung@xxxxxxxxxx> wrote: > > On 05/26/14 at 04:39pm, Dave Young wrote: > >> > >> For efi=old_map and any old_map quirks like SGI UV in current > >> tree kexec/kdump will fail because it depends on the new 1:1 mapping. > >> > >> Thus export the mapping method to sysfs so kexec tools can switch > >> to original way to boot. > >> > >> Since we have efi.flags for all efi facilities so let's just export the > >> efi.flags itself, it maybe useful for other arches and use cases. > > > > Rethink about this issue, export flags will expose the efi facility > > macros to userspace, Matt, what's your opinion? It might be better to export > > a file 'old_map' only which is '0|1' > > Exporting efi.flags is a non-starter. Those flags are part of an > internal interface and I'm not prepared to turn them into a userspace > ABI that we can never, ever change without a massive amount of pain. Agree that it's not good to move them to external ones. > > I've only vaguely been following along with the other thread, so please > summarise everything again in your patch. Particularly, I need answers > to the following questions, > > - Are you trying to fix a kexec/kdump regression? Somehow it is a regression. Before the 1:1 mapping kexec/kdump works with 'noefi' plus acpi_rsdp= kernel cmdline. kexec-tools does not fill efi_info in boot_params so kexec kernel will simply boot like 'noefi'. Now we have 1:1 mapping, kexec-tools will boot with efi enabled but SGI UV is still using old maping thus it become a problem. So kexec-tools need to know whether it's old_map or nor so it can switch to the right way in case efi boot. > - Does SGI UV work with kexec + UEFI at all? It works previously without enabling efi in boot_params. > > The 1:1 mapping was required to make kexec + EFI work in the first > instance. If a machine implements the EFI 1:1 mapping, kexec should > work. If it doesn't implement the 1:1 mapping, then it's probably not > going to work, right? > > The crux of the question: are you trying to fix a regression? > > If not, then we just need to get SGI UV working with the EFI 1:1 > mapping. No? Ditto as before explanation... Thanks Dave -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
