Hi, Matt Thanks for the feedback. On 01/26/15 at 04:39pm, Matt Fleming wrote: > On Sat, 24 Jan, at 09:26:37PM, Dave Young wrote: > > > > There's several things I need to ask for help from EFI gurus to see if it is doable: > > > > * Make sure in case EFI warm reboot the memory of previous kernel can be retained. > > The only way to reserve memory across a reboot is with EFI capsules. I know your capsules patchset, but I did not look into the details. Do you means the old memory will be not reliable in case booting without capsules even for warm reboot? > > > * How to determine if kernel is boot with EFI warm reboot in stub > > The presence of a capsule would indicate whether we were invoked from a > crash handler. Ok, another problem is for efi capsule handling, can we do it in efi stub, or I in a efi application, which stage is the doable? > > > * What is the right way to pass informations from 1st kernel to 2nd kernel. > > Is it ok for saving something with efi variables? > > EFI capsules would the be most natural mechanism, but you could > conceivably do it with EFI variables (there's an upper limit on the size > of variable data, though). Will think about it after I checking the capsule machanisms details. > > > * Other possible problems what I missed > > Support for runtime EFI capsules was rather spotty last time I looked. > Things may have moved on, but it's definitely something to watch out > for. > > There have been patches on linux-efi in recent months for making use of > EFI capsules, > > https://lkml.kernel.org/r/1412692886-25306-1-git-send-email-matt at console-pimps.org > https://lkml.kernel.org/r/1414984030-13859-1-git-send-email-hock.leong.kweh at intel.com > > I could take a look at resubmitting the first series above if that would > be useful for doing kexec across a reset. Thanks a lot. I will take a look at how capsules works firstly. Dave
