Some user space tools such as kexec-tools resort to the event
add/remove to decide whether rebuilding dtb or not.
So if a new core added and a crash happens on one of its thread,
then kexec fails to bring up the 2nd kernel since lacking the info
of boot-cpu-hwid in dtb. This patch uses the interface
register_/unregister_cpu to fix the problem
Signed-off-by: Pingfan Liu <kernelf...@gmail.com>
Reported-by: Hari Bathini <hbath...@linux.vnet.ibm.com>
---
arch/powerpc/include/asm/smp.h | 1 +
arch/powerpc/kernel/sysfs.c | 26 ++++++++++++++------------
arch/powerpc/platforms/pseries/hotplug-cpu.c | 3 ++-
3 files changed, 17 insertions(+), 13 deletions(-)
diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h
index fac963e..3ef730d 100644
--- a/arch/powerpc/include/asm/smp.h
+++ b/arch/powerpc/include/asm/smp.h
@@ -35,6 +35,7 @@ extern int spinning_secondaries;
extern void cpu_die(void);
extern int cpu_to_chip_id(int cpu);
+DECLARE_PER_CPU(struct cpu, cpu_devices);
#ifdef CONFIG_SMP
struct smp_ops_t {
diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
index 04d0bbd..dbbcc96 100644
--- a/arch/powerpc/kernel/sysfs.c
+++ b/arch/powerpc/kernel/sysfs.c
@@ -26,7 +26,7 @@
#include <asm/lppaca.h>
#endif
-static DEFINE_PER_CPU(struct cpu, cpu_devices);
+DEFINE_PER_CPU(struct cpu, cpu_devices);
/*
* SMT snooze delay stuff, 64-bit only for now
@@ -716,6 +716,16 @@ static struct device_attribute pa6t_attrs[] = {
#endif /* HAS_PPC_PMC_PA6T */
#endif /* HAS_PPC_PMC_CLASSIC */
+/* Only valid if CPU is present. */
+static ssize_t show_physical_id(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct cpu *cpu = container_of(dev, struct cpu, dev);
+
+ return sprintf(buf, "%d\n", get_hard_smp_processor_id(cpu->dev.id));
+}
+static DEVICE_ATTR(physical_id, 0444, show_physical_id, NULL);
+
static int register_cpu_online(unsigned int cpu)
{
struct cpu *c = &per_cpu(cpu_devices, cpu);
@@ -723,6 +733,8 @@ static int register_cpu_online(unsigned int cpu)
struct device_attribute *attrs, *pmc_attrs;
int i, nattrs;
+ device_create_file(&c->dev, &dev_attr_physical_id);
+
/* For cpus present at boot a reference was already grabbed in
register_cpu() */
if (!s->of_node)
s->of_node = of_get_cpu_node(cpu, NULL);
@@ -816,6 +828,7 @@ static int unregister_cpu_online(unsigned int cpu)
BUG_ON(!c->hotpluggable);
+ device_remove_file(s, &dev_attr_physical_id);
#ifdef CONFIG_PPC64
if (cpu_has_feature(CPU_FTR_SMT))
device_remove_file(s, &dev_attr_smt_snooze_delay);
@@ -1017,16 +1030,6 @@ static void register_nodes(void)
#endif
-/* Only valid if CPU is present. */
-static ssize_t show_physical_id(struct device *dev,
- struct device_attribute *attr, char *buf)
-{
- struct cpu *cpu = container_of(dev, struct cpu, dev);
-
- return sprintf(buf, "%d\n", get_hard_smp_processor_id(cpu->dev.id));
-}
-static DEVICE_ATTR(physical_id, 0444, show_physical_id, NULL);
-
static int __init topology_init(void)
{
int cpu, r;
@@ -1049,7 +1052,6 @@ static int __init topology_init(void)
if (cpu_online(cpu) || c->hotpluggable) {
register_cpu(c, cpu);
- device_create_file(&c->dev, &dev_attr_physical_id);
}
}
r = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "powerpc/topology:online",
diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c
b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index 652d3e96..697dfb7 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -367,6 +367,7 @@ static int dlpar_online_cpu(struct device_node *dn)
cpu_maps_update_done();
timed_topology_update(1);
find_and_online_cpu_nid(cpu);
+ register_cpu(&per_cpu(cpu_devices, cpu), cpu);
rc = device_online(get_cpu_device(cpu));
if (rc)
goto out;
@@ -541,6 +542,7 @@ static int dlpar_offline_cpu(struct device_node *dn)
rc = device_offline(get_cpu_device(cpu));
if (rc)
goto out;
+
unregister_cpu(container_of(get_cpu_device(cpu), struct cpu, dev));
cpu_maps_update_begin();
break;
@@ -599,7 +601,6 @@ static ssize_t dlpar_cpu_remove(struct device_node *dn, u32
drc_index)
return saved_rc;
}
-
pr_debug("Successfully removed CPU, drc index: %x\n", drc_index);
return 0;
}
--
2.7.4
