Re: -tip tree resume fail, bisect to 5bd5a45(x86: Add NX protection for kernel data)

[Lin Ming <ming.m.lin@intel.com>]

On Sat, 2010-12-25 at 01:26 +0800, matthieu castet wrote:
> Hi,
> 
> Le Tue, 30 Nov 2010 13:00:30 +0800,
> Lin Ming <ming.m.lin@intel.com> a écrit :
> 
> > On Sat, 2010-11-27 at 01:31 +0800, mat wrote:
> > > Le Tue, 23 Nov 2010 23:55:27 +0100,
> > > mat <castet.matthieu@free.fr> a écrit :
> > > 
> > > > Le Mon, 22 Nov 2010 17:42:47 +0100,
> > > > Andi Kleen <andi@firstfloor.org> a écrit :
> > > > 
> > > > > > That seems to be a S3 specific code path, that won't fix
> > > > > > anything. Simply do:
> > > > > > 
> > > > > > echo 0 > /sys/devices/system/cpu/cpu1/online;
> > > > > > echo 1 > /sys/devices/system/cpu/cpu1/online;
> > > > > > 
> > > > > > and your machine will explode..
> > > > > 
> > > > > The SMP startup trampoline is copied I believe
> > > > > and only executed in real mode without page tables.
> > > > > 
> > > > > So it's perhaps not the trampoline, but the early startup 
> > > > > code that ends up being broken.
> > > > yes :
> > > > acpi wakeup code and smp trampoline are copied in low memory
> > > > (first 1MB).
> > > > 
> > > > So they can't end up int the kernel data mapping ?
> > > > 
> > > > So it should something else.
> > > > 
> > > > I will try to investigate on this.
> > > > 
> > > Unfortunately on my laptop supporting NX, suspend to ram seems
> > > broken (even without this patch) and I got only one core, so I am
> > > unable to test it.
> > > 
> > > Does cpu suspend/resume is broken ? Or it is only S3 ?
> > > 
> > > If yes, are there any interesting trace if we suspend only one core
> > > with sysfs.
> > 
> > echo 0 > /sys/devices/system/cpu/cpu1/online;
> > echo 1 > /sys/devices/system/cpu/cpu1/online;
> > 
> > then machine just reboots...
> > 
> Ok,
> 
> could you try the attached patch ?

Unfortunately, it does not work against current tip/master(1f7107c8).

Lin Ming

> 
> Thanks
> 
> Matthieu