[3.8.y.z extended stable] Patch "powerpc: Don't skip ePAPR spin-table CPUs" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    powerpc: Don't skip ePAPR spin-table CPUs

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.27.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 44468a64e63ceac893660026c7e7311a1f859676 Mon Sep 17 00:00:00 2001
From: Scott Wood <scottwood at freescale.com>
Date: Tue, 24 Jun 2014 20:15:51 -0500
Subject: powerpc: Don't skip ePAPR spin-table CPUs

commit 6663a4fa6711050036562ddfd2086edf735fae21 upstream.

Commit 59a53afe70fd530040bdc69581f03d880157f15a "powerpc: Don't setup
CPUs with bad status" broke ePAPR SMP booting.  ePAPR says that CPUs
that aren't presently running shall have status of disabled, with
enable-method being used to determine whether the CPU can be enabled.

Fix by checking for spin-table, which is currently the only supported
enable-method.

Signed-off-by: Scott Wood <scottwood at freescale.com>
Cc: Michael Neuling <mikey at neuling.org>
Cc: Emil Medve <Emilian.Medve at Freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 arch/powerpc/kernel/setup-common.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index b050263..069f857 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -455,9 +455,17 @@ void __init smp_setup_cpu_maps(void)
 		}

 		for (j = 0; j < nthreads && cpu < nr_cpu_ids; j++) {
+			bool avail;
+
 			DBG("    thread %d -> cpu %d (hard id %d)\n",
 			    j, cpu, intserv[j]);
-			set_cpu_present(cpu, of_device_is_available(dn));
+
+			avail = of_device_is_available(dn);
+			if (!avail)
+				avail = !of_property_match_string(dn,
+						"enable-method", "spin-table");
+
+			set_cpu_present(cpu, avail);
 			set_hard_smp_processor_id(cpu, intserv[j]);
 			set_cpu_possible(cpu, true);
 			cpu++;
--
1.9.1