From 1d9a090783bef19fe8cdec878620d22f05191316 Mon Sep 17 00:00:00 2001
From: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Date: Fri, 26 Jan 2018 13:41:59 -0600
Subject: powerpc/numa: Invalidate numa_cpu_lookup_table on cpu remove
When DLPAR removing a CPU, the unmapping of the cpu from a node in
unmap_cpu_from_node() should also invalidate the CPUs entry in the
numa_cpu_lookup_table. There is not a guarantee that on a subsequent
DLPAR add of the CPU the associativity will be the same and thus
could be in a different node. Invalidating the entry in the
numa_cpu_lookup_table causes the associativity to be read from the
device tree at the time of the add.
The current behavior of not invalidating the CPUs entry in the
numa_cpu_lookup_table can result in scenarios where the the topology
layout of CPUs in the partition does not match the device tree
or the topology reported by the HMC.
This bug looks like it was introduced in 2004 in the commit titled
"ppc64: cpu hotplug notifier for numa", which is 6b15e4e87e32 in the
linux-fullhist tree. Hence tag it for all stable releases.
Cc: stable@vger.kernel.org
Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Reviewed-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
arch/powerpc/include/asm/topology.h | 5 +++++
1 file changed, 5 insertions(+)
(limited to 'arch/powerpc/include/asm/topology.h')
diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
index 88187c285c70..1c02e6900f78 100644
--- a/arch/powerpc/include/asm/topology.h
+++ b/arch/powerpc/include/asm/topology.h
@@ -44,6 +44,11 @@ extern int sysfs_add_device_to_node(struct device *dev, int nid);
extern void sysfs_remove_device_from_node(struct device *dev, int nid);
extern int numa_update_cpu_topology(bool cpus_locked);
+static inline void update_numa_cpu_lookup_table(unsigned int cpu, int node)
+{
+ numa_cpu_lookup_table[cpu] = node;
+}
+
static inline int early_cpu_to_node(int cpu)
{
int nid;
--
cgit v1.2.1
From 82343484a2d4c97a03bfd81303b5493c65f05c50 Mon Sep 17 00:00:00 2001
From: Guenter Roeck <linux@roeck-us.net>
Date: Mon, 12 Feb 2018 14:34:08 -0800
Subject: powerpc/pseries: Fix build break for SPLPAR=n and CPU hotplug
Commit e67e02a544e9 ("powerpc/pseries: Fix cpu hotplug crash with
memoryless nodes") adds an unconditional call to
find_and_online_cpu_nid(), which is only declared if CONFIG_PPC_SPLPAR
is enabled. This results in the following build error if this is not
the case.
arch/powerpc/platforms/pseries/hotplug-cpu.o: In function `dlpar_online_cpu':
arch/powerpc/platforms/pseries/hotplug-cpu.c:369:
undefined reference to `.find_and_online_cpu_nid'
Follow the guideline provided by similar functions and provide a dummy
function if CONFIG_PPC_SPLPAR is not enabled. This also moves the
external function declaration into an include file where it should be.
Fixes: e67e02a544e9 ("powerpc/pseries: Fix cpu hotplug crash with memoryless nodes")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
[mpe: Change subject to emphasise the build fix]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
arch/powerpc/include/asm/topology.h | 5 +++++
1 file changed, 5 insertions(+)
(limited to 'arch/powerpc/include/asm/topology.h')
diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
index 1c02e6900f78..593248110902 100644
--- a/arch/powerpc/include/asm/topology.h
+++ b/arch/powerpc/include/asm/topology.h
@@ -87,6 +87,7 @@ static inline int numa_update_cpu_topology(bool cpus_locked)
extern int start_topology_update(void);
extern int stop_topology_update(void);
extern int prrn_is_enabled(void);
+extern int find_and_online_cpu_nid(int cpu);
#else
static inline int start_topology_update(void)
{
@@ -100,6 +101,10 @@ static inline int prrn_is_enabled(void)
{
return 0;
}
+static inline int find_and_online_cpu_nid(int cpu)
+{
+ return 0;
+}
#endif /* CONFIG_NUMA && CONFIG_PPC_SPLPAR */
#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_NEED_MULTIPLE_NODES)
--
cgit v1.2.1
From c1e150ceb61e4a585bad156da15c33bfe89f5858 Mon Sep 17 00:00:00 2001
From: Corentin Labbe <clabbe@baylibre.com>
Date: Wed, 14 Feb 2018 12:17:47 +0000
Subject: powerpc/pseries: Add empty update_numa_cpu_lookup_table() for NUMA=n
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
When CONFIG_NUMA is not set, the build fails with:
arch/powerpc/platforms/pseries/hotplug-cpu.c:335:4:
error: déclaration implicite de la fonction « update_numa_cpu_lookup_table »
So we have to add update_numa_cpu_lookup_table() as an empty function
when CONFIG_NUMA is not set.
Fixes: 1d9a090783be ("powerpc/numa: Invalidate numa_cpu_lookup_table on cpu remove")
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
arch/powerpc/include/asm/topology.h | 3 +++
1 file changed, 3 insertions(+)
(limited to 'arch/powerpc/include/asm/topology.h')
diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
index 593248110902..9f421641a35c 100644
--- a/arch/powerpc/include/asm/topology.h
+++ b/arch/powerpc/include/asm/topology.h
@@ -81,6 +81,9 @@ static inline int numa_update_cpu_topology(bool cpus_locked)
{
return 0;
}
+
+static inline void update_numa_cpu_lookup_table(unsigned int cpu, int node) {}
+
#endif /* CONFIG_NUMA */
#if defined(CONFIG_NUMA) && defined(CONFIG_PPC_SPLPAR)
--
cgit v1.2.1