On Fri, May 09, 2014 at 01:48:17AM +0100, Geoff Levand wrote: > Hi Maintainers, > > This patchset adds support for kexec re-boots on arm64. I have tested with the > VE fast model using various kernel config options with both spin and psci enable > methods. I'll continue to test in the coming weeks. > > I tried to re-use the existing hot plug cpu_ops support for the secondary CPU > shutdown as much as possible, but needed to do some things specific to kexec > that I couldn't do with what was already there. A significant change is in > [PATCH 4/8] (arm64: Add smp_spin_table_set_die) where I add the ability to setup > a custom cpu_die handler. > > To get the the spin-table secondary CPUs into the proper state described in > Documentation/arm64/booting.txt I use a three step spin loop. First in the > kernel's virtual address space, then to the identity mapped address, then jump > to the final spin code in the 2nd stage kernel's /memreserve/ area. To support > this three step spin I needed [PATCH 5/8] (arm64: Split soft_restart into two > stages). Please see the patch comments for more info. If we added the 2nd > stage kernel's /memreserve/ area to the identity map we could eliminate the > middle step and go from the VA space to the /memreserve/ area directly. As I've covered in my reply to patch 7 [1] I don't think this is a good approach. I think a vastly better approach is to make kexec depend on cpu hotplug support in SMP, and enable a simple hotplug-capable boot protocol (e.g. extend spin-table with a cpu-return-addr). That way the in-kernel portions of kexec can use the existing infrastructure without tonnes of point hacks, and we enable a generic hotplug capable mechanism for those systems which cannot implement PSCI. > > Please consider all patches for inclusion. Any comments or suggestions on how > to improve would be very welcome. > > To load a kexec kernel and execute a kexec re-boot on arm64 my patches to > kexec-tools, which have not yet been merged upstream, are needed: > > https://git.linaro.org/people/geoff.levand/kexec-tools.git Is the master branch up-to-date? The commit dates on all branches I can see imply they haven't been updated in a while, and the code looks like it needs some cleanup (there are some unused functions, hard-coded values, etc). Cheers, Mark. [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2014-May/254819.html
