On Sat, Feb 22, 2014 at 10:16:55AM +0000, Russell King - ARM Linux wrote: > On Thu, Feb 20, 2014 at 04:27:55PM +0000, Lorenzo Pieralisi wrote: > > I still do not understand why switching to idmap, which is a clone of > > init_mm + 1:1 kernel mappings is required here. Why idmap ? > > > > And while at it, can't the idmap be overwritten _while_ copying back the > > resume kernel ? Is it safe to use idmap page tables while copying ? > > > > I had a look at x86 and there idmap page tables used to resume are created > > on the fly using safe pages, on ARM idmap is created at boot. > > That's fine. > > Remember, you're required to boot exactly the same kernel image when > resuming as the kernel which created the suspend image. Unless you > have random allocations going on, you should get the same layout for > the idmap stuff at each boot.
Thanks Russell, now that's clear. We do need a copy of page tables that are not tampered with while copying, and idmap works well for that. Lorenzo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
