From mboxrd@z Thu Jan 1 00:00:00 1970 From: geoff@infradead.org (Geoff Levand) Date: Thu, 24 Jul 2014 17:17:48 -0700 Subject: Kexec on arm64 In-Reply-To: <20140724093603.GC4079@leverpostej> References: <1405443898.22585.7.camel@smoke> <1405551861.7262.26.camel@smoke> <1406162287.4062.39.camel@smoke> <20140724093603.GC4079@leverpostej> Message-ID: <1406247468.4062.59.camel@smoke> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, On Thu, 2014-07-24 at 10:36 +0100, Mark Rutland wrote: > On Thu, Jul 24, 2014 at 01:38:07AM +0100, Geoff Levand wrote: > > All memory management for the main cpu is done by the arch code. Kexec > > and cpu hot plug only work with the secondary cpus, so the problem would > > be in the arch memory code, either in setup_restart() for shutdown, or > > in the startup code. > > It's possible that soft_restart and setup_restart are a little dodgy, as > they also rely on the compiler being smart and not touching the stack > after setup_restart(). > > However, they provide absolutely no guarantee that any data has been > flushed out to the PoC [1]. If you require any data to be flushed out to the > PoC so as to be visible to noncacheable accesses, you will need to > ensure that this is flushed by VA before soft_restart is called. Data > may have migrated to another cache (e.g. another CPU, or the L3) where > it is not visible. OK, kexec's reset routine relocate_new_kernel does use a few global variables that are set by the main kexec routines. I added a call to __flush_dcache_area(), which uses 'dc civac' for those. I had thought the call to __flush_dcache_all, which uses 'dc cisw', in flush_cache_all() would be enough. Arun, I also fixed UP builds. Could you pull my latest and try with L3 enabled? -Geoff