On Wed, Feb 15, 2017 at 12:12:35PM +0000, James Morse wrote: > Hi Akashi, > > On 07/02/17 08:08, AKASHI Takahiro wrote: > > Since arch_kexec_protect_crashkres() removes a mapping for crash dump > > kernel memory, the loaded contents won't be preserved around hibernation. > > > > In this patch, arch_kexec_(un)protect_crashkres() are additionally called > > before/after hibernation so that the relevant region will be mapped again > > and restored just as the other memory regions are. > > Reviewed-by: James Morse <james.morse at arm.com> Thank you very much. > A quick test of this took longer than expected (writing to a slow usb device), Really? I use a uSD card on hikey as a swap device, and it takes just a few moments to save a hibernate image although I do the test right after the system comes up. > I > suspect it is save/restoring the whole crash region (which I don't think is a > problem). Now that we have only page-level mappings for the crash region, it might be possible to mark all the unused pages "reserved" in arch_kexec_unprotect_crashkres() if called in hibernate. -Takahiro AKASHI > If someone turns out to use this combination of features I will look > at improving this, (almost certainly requires core-code changes). > > > Thanks, > > James
