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powerpc: Bring all threads online prior to migration/hibernation

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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>
This commit is contained in:
Robert Jennings 2013-05-07 04:34:11 +00:00 • committed by Benjamin Herrenschmidt
commit 120496ac2d
3 changed files with 137 additions and 0 deletions
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2
arch/powerpc/include/asm/rtas.h
View file

@ -264,6 +264,8 @@ extern void rtas_progress(char *s, unsigned short hex);
extern void rtas_initialize(void);
extern int rtas_suspend_cpu(struct rtas_suspend_me_data *data);
extern int rtas_suspend_last_cpu(struct rtas_suspend_me_data *data);
extern int rtas_online_cpus_mask(cpumask_var_t cpus);
extern int rtas_offline_cpus_mask(cpumask_var_t cpus);
extern int rtas_ibm_suspend_me(struct rtas_args *);
struct rtc_time;

113
arch/powerpc/kernel/rtas.c
View file

@ -19,6 +19,7 @@
#include <linux/init.h>
#include <linux/capability.h>
#include <linux/delay.h>
#include <linux/cpu.h>
#include <linux/smp.h>
#include <linux/completion.h>
#include <linux/cpumask.h>
@ -807,6 +808,95 @@ static void rtas_percpu_suspend_me(void *info)
__rtas_suspend_cpu((struct rtas_suspend_me_data *)info, 1);
}
enum rtas_cpu_state {
DOWN,
UP,
};
#ifndef CONFIG_SMP
static int rtas_cpu_state_change_mask(enum rtas_cpu_state state,
cpumask_var_t cpus)
{
if (!cpumask_empty(cpus)) {
cpumask_clear(cpus);
return -EINVAL;
} else
return 0;
}
#else
/* On return cpumask will be altered to indicate CPUs changed.
* CPUs with states changed will be set in the mask,
* CPUs with status unchanged will be unset in the mask. */
static int rtas_cpu_state_change_mask(enum rtas_cpu_state state,
cpumask_var_t cpus)
{
int cpu;
int cpuret = 0;
int ret = 0;
if (cpumask_empty(cpus))
return 0;
for_each_cpu(cpu, cpus) {
switch (state) {
case DOWN:
cpuret = cpu_down(cpu);
break;
case UP:
cpuret = cpu_up(cpu);
break;
}
if (cpuret) {
pr_debug("%s: cpu_%s for cpu#%d returned %d.\n",
__func__,
((state == UP) ? "up" : "down"),
cpu, cpuret);
if (!ret)
ret = cpuret;
if (state == UP) {
/* clear bits for unchanged cpus, return */
cpumask_shift_right(cpus, cpus, cpu);
cpumask_shift_left(cpus, cpus, cpu);
break;
} else {
/* clear bit for unchanged cpu, continue */
cpumask_clear_cpu(cpu, cpus);
}
}
}
return ret;
}
#endif
int rtas_online_cpus_mask(cpumask_var_t cpus)
{
int ret;
ret = rtas_cpu_state_change_mask(UP, cpus);
if (ret) {
cpumask_var_t tmp_mask;
if (!alloc_cpumask_var(&tmp_mask, GFP_TEMPORARY))
return ret;
/* Use tmp_mask to preserve cpus mask from first failure */
cpumask_copy(tmp_mask, cpus);
rtas_offline_cpus_mask(tmp_mask);
free_cpumask_var(tmp_mask);
}
return ret;
}
EXPORT_SYMBOL(rtas_online_cpus_mask);
int rtas_offline_cpus_mask(cpumask_var_t cpus)
{
return rtas_cpu_state_change_mask(DOWN, cpus);
}
EXPORT_SYMBOL(rtas_offline_cpus_mask);
int rtas_ibm_suspend_me(struct rtas_args *args)
{
long state;
@ -814,6 +904,8 @@ int rtas_ibm_suspend_me(struct rtas_args *args)
unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
struct rtas_suspend_me_data data;
DECLARE_COMPLETION_ONSTACK(done);
cpumask_var_t offline_mask;
int cpuret;
if (!rtas_service_present("ibm,suspend-me"))
return -ENOSYS;
@ -837,11 +929,24 @@ int rtas_ibm_suspend_me(struct rtas_args *args)
return 0;
}
if (!alloc_cpumask_var(&offline_mask, GFP_TEMPORARY))
return -ENOMEM;
atomic_set(&data.working, 0);
atomic_set(&data.done, 0);
atomic_set(&data.error, 0);
data.token = rtas_token("ibm,suspend-me");
data.complete = &done;
/* All present CPUs must be online */
cpumask_andnot(offline_mask, cpu_present_mask, cpu_online_mask);
cpuret = rtas_online_cpus_mask(offline_mask);
if (cpuret) {
pr_err("%s: Could not bring present CPUs online.\n", __func__);
atomic_set(&data.error, cpuret);
goto out;
}
stop_topology_update();
/* Call function on all CPUs. One of us will make the
@ -857,6 +962,14 @@ int rtas_ibm_suspend_me(struct rtas_args *args)
start_topology_update();
/* Take down CPUs not online prior to suspend */
cpuret = rtas_offline_cpus_mask(offline_mask);
if (cpuret)
pr_warn("%s: Could not restore CPUs to offline state.\n",
__func__);
out:
free_cpumask_var(offline_mask);
return atomic_read(&data.error);
}
#else /* CONFIG_PPC_PSERIES */

22
arch/powerpc/platforms/pseries/suspend.c
View file

@ -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 @@ static ssize_t store_hibernate(struct device *dev,
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 @@ static ssize_t store_hibernate(struct device *dev,
} 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;
}