powerpc: Bring all threads online prior to migration/hibernation
This patch brings online all threads which are present but not online
prior to migration/hibernation. After migration/hibernation those
threads are taken back offline.
During migration/hibernation all online CPUs must call H_JOIN, this is
required by the hypervisor. Without this patch, threads that are offline
(H_CEDE'd) will not be woken to make the H_JOIN call and the OS will be
deadlocked (all threads either JOIN'd or CEDE'd).
Cc: <stable@kernel.org>
Signed-off-by: Robert Jennings <rcj@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/platforms/pseries/suspend.c b/arch/powerpc/platforms/pseries/suspend.c
index 47226e0..5f997e7 100644
--- a/arch/powerpc/platforms/pseries/suspend.c
+++ b/arch/powerpc/platforms/pseries/suspend.c
@@ -16,6 +16,7 @@
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
+#include <linux/cpu.h>
#include <linux/delay.h>
#include <linux/suspend.h>
#include <linux/stat.h>
@@ -126,11 +127,15 @@
struct device_attribute *attr,
const char *buf, size_t count)
{
+ cpumask_var_t offline_mask;
int rc;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
+ if (!alloc_cpumask_var(&offline_mask, GFP_TEMPORARY))
+ return -ENOMEM;
+
stream_id = simple_strtoul(buf, NULL, 16);
do {
@@ -140,15 +145,32 @@
} while (rc == -EAGAIN);
if (!rc) {
+ /* All present CPUs must be online */
+ cpumask_andnot(offline_mask, cpu_present_mask,
+ cpu_online_mask);
+ rc = rtas_online_cpus_mask(offline_mask);
+ if (rc) {
+ pr_err("%s: Could not bring present CPUs online.\n",
+ __func__);
+ goto out;
+ }
+
stop_topology_update();
rc = pm_suspend(PM_SUSPEND_MEM);
start_topology_update();
+
+ /* Take down CPUs not online prior to suspend */
+ if (!rtas_offline_cpus_mask(offline_mask))
+ pr_warn("%s: Could not restore CPUs to offline "
+ "state.\n", __func__);
}
stream_id = 0;
if (!rc)
rc = count;
+out:
+ free_cpumask_var(offline_mask);
return rc;
}