Messages in this thread | | | Date | Wed, 5 Jan 2011 19:58:16 +0100 | From | matthieu castet <> | Subject | Re: -tip tree resume fail, bisect to 5bd5a45(x86: Add NX protection for kernel data) |
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Le Mon, 27 Dec 2010 10:10:50 +0800, Lin Ming <ming.m.lin@intel.com> a écrit :
> 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 for the testing.
For the record I did some tests. - The x86_32 cpu hotplug is working fine. - On x86_64 we crash between the cpu1 is wakeup and before trampoline jump to start_secondary
A difference between 32 and 64 bit is that head_32.S use initial_page_table mmu table then switch to swapper_pg_dir while 64 bit version use init_level4_pgt for trampoline, head and kernel.
But I fail to see where setting NX is level3_kernel_pgt aera can make the resume fail. When we enable NX we are in .text section (head_64).
Matthieu -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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