On Friday, 25 of January 2008, Pavel Machek wrote: > On Thu 2008-01-24 16:27:58, H. Peter Anvin wrote: > > Pavel Machek wrote: > > >>> > > >>I just looked at the ACPI suspend code, and it looks > > >>like it hacks its own identity map at runtime. Pavel, > > >>am I reading that code right? > > > > > >Yes, I think so, I believe we do it on both 32 and 64 > > >bit now. > > > > > > > So the background to this... we need an identity map to > > trampoline at early boot, obviously, but we'd like it to > > not stick around more than necessary. We have > > zap_low_mappings() now but it's not really sufficient. > > > > Secondary SMP processors need these mappings during > > trampolining -- presumably including CPU hotplug -- and > > I'm suspecting it might simply make sense to use a > > separate set of page tables (with both the identity and > > the kernel map) for trampolining and just keep them > > around. That way they would be usable for ACPI as well. > > That would enable some cleanups, yes.
Speaking of cleanups, the following one is applicable IMO. Greetings, Rafael --- arch/x86/mm/init_32.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) Index: linux-2.6/arch/x86/mm/init_32.c =================================================================== --- linux-2.6.orig/arch/x86/mm/init_32.c +++ linux-2.6/arch/x86/mm/init_32.c @@ -444,23 +444,23 @@ static void __init pagetable_init (void) paravirt_pagetable_setup_done(pgd_base); } -#if defined(CONFIG_HIBERNATION) || defined(CONFIG_ACPI) +#ifdef CONFIG_SUSPEND /* * Swap suspend & friends need this for resume because things like the intel-agp * driver might have split up a kernel 4MB mapping. */ -char __nosavedata swsusp_pg_dir[PAGE_SIZE] +char swsusp_pg_dir[PAGE_SIZE] __attribute__ ((aligned (PAGE_SIZE))); static inline void save_pg_dir(void) { memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE); } -#else +#else /* !CONFIG_SUSPEND */ static inline void save_pg_dir(void) { } -#endif +#endif /* !CONFIG_SUSPEND */ void zap_low_mappings (void) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/