[PATCH 4.9 068/104] cpuidle: powernv: Pass correct drv->cpumask for registration

2017-12-22 Thread Greg Kroah-Hartman 
4.9-stable review patch.  If anyone has any objections, please let me know.

--

From: Vaidyanathan Srinivasan 


[ Upstream commit 293d264f13cbde328d5477f49e3103edbc1dc191 ]

drv->cpumask defaults to cpu_possible_mask in __cpuidle_driver_init().
On PowerNV platform cpu_present could be less than cpu_possible in cases
where firmware detects the cpu, but it is not available to the OS.  When
CONFIG_HOTPLUG_CPU=n, such cpus are not hotplugable at runtime and hence
we skip creating cpu_device.

This breaks cpuidle on powernv where register_cpu() is not called for
cpus in cpu_possible_mask that cannot be hot-added at runtime.

Trying cpuidle_register_device() on cpu without cpu_device will cause
crash like this:

cpu 0xf: Vector: 380 (Data SLB Access) at [c00ff1503490]
pc: c022c8bc: string+0x34/0x60
lr: c022ed78: vsnprintf+0x284/0x42c
sp: c00ff1503710
   msr: 90009033
   dar: 60006000
  current = 0xc00ff148
  paca= 0xcfe82d00   softe: 0irq_happened: 0x01
pid   = 1, comm = swapper/8
Linux version 4.11.0-rc2 (sv@sagarika) (gcc version 4.9.4
(Buildroot 2017.02-4-gc28573e) ) #15 SMP Fri Mar 17 19:32:02 IST 2017
enter ? for help
[link register   ] c022ed78 vsnprintf+0x284/0x42c
[c00ff1503710] c022ebb8 vsnprintf+0xc4/0x42c (unreliable)
[c00ff1503800] c022ef40 vscnprintf+0x20/0x44
[c00ff1503830] c00ab61c vprintk_emit+0x94/0x2cc
[c00ff15038a0] c00acc9c vprintk_func+0x60/0x74
[c00ff15038c0] c0619694 printk+0x38/0x4c
[c00ff15038e0] c0224950 kobject_get+0x40/0x60
[c00ff1503950] c022507c kobject_add_internal+0x60/0x2c4
[c00ff15039e0] c0225350 kobject_init_and_add+0x70/0x78
[c00ff1503a60] c053c288 cpuidle_add_sysfs+0x9c/0xe0
[c00ff1503ae0] c053aeac cpuidle_register_device+0xd4/0x12c
[c00ff1503b30] c053b108 cpuidle_register+0x98/0xcc
[c00ff1503bc0] c085eaf0 powernv_processor_idle_init+0x140/0x1e0
[c00ff1503c60] c000cd60 do_one_initcall+0xc0/0x15c
[c00ff1503d20] c0833e84 kernel_init_freeable+0x1a0/0x25c
[c00ff1503dc0] c000d478 kernel_init+0x24/0x12c
[c00ff1503e30] c000b564 ret_from_kernel_thread+0x5c/0x78

This patch fixes the bug by passing correct cpumask from
powernv-cpuidle driver.

Signed-off-by: Vaidyanathan Srinivasan 
Reviewed-by: Gautham R. Shenoy 
Acked-by: Michael Ellerman 
[ rjw: Comment massage ]
Signed-off-by: Rafael J. Wysocki 

Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman 
---
 drivers/cpuidle/cpuidle-powernv.c |   18 ++
 1 file changed, 18 insertions(+)

--- a/drivers/cpuidle/cpuidle-powernv.c
+++ b/drivers/cpuidle/cpuidle-powernv.c
@@ -164,6 +164,24 @@ static int powernv_cpuidle_driver_init(v
drv->state_count += 1;
}
 
+   /*
+* On the PowerNV platform cpu_present may be less than cpu_possible in
+* cases when firmware detects the CPU, but it is not available to the
+* OS.  If CONFIG_HOTPLUG_CPU=n, then such CPUs are not hotplugable at
+* run time and hence cpu_devices are not created for those CPUs by the
+* generic topology_init().
+*
+* drv->cpumask defaults to cpu_possible_mask in
+* __cpuidle_driver_init().  This breaks cpuidle on PowerNV where
+* cpu_devices are not created for CPUs in cpu_possible_mask that
+* cannot be hot-added later at run time.
+*
+* Trying cpuidle_register_device() on a CPU without a cpu_device is
+* incorrect, so pass a correct CPU mask to the generic cpuidle driver.
+*/
+
+   drv->cpumask = (struct cpumask *)cpu_present_mask;
+
return 0;
 }

[PATCH 4.9 068/104] cpuidle: powernv: Pass correct drv->cpumask for registration

2017-12-22 Thread Greg Kroah-Hartman 
4.9-stable review patch.  If anyone has any objections, please let me know.

--

From: Vaidyanathan Srinivasan 


[ Upstream commit 293d264f13cbde328d5477f49e3103edbc1dc191 ]

drv->cpumask defaults to cpu_possible_mask in __cpuidle_driver_init().
On PowerNV platform cpu_present could be less than cpu_possible in cases
where firmware detects the cpu, but it is not available to the OS.  When
CONFIG_HOTPLUG_CPU=n, such cpus are not hotplugable at runtime and hence
we skip creating cpu_device.

This breaks cpuidle on powernv where register_cpu() is not called for
cpus in cpu_possible_mask that cannot be hot-added at runtime.

Trying cpuidle_register_device() on cpu without cpu_device will cause
crash like this:

cpu 0xf: Vector: 380 (Data SLB Access) at [c00ff1503490]
pc: c022c8bc: string+0x34/0x60
lr: c022ed78: vsnprintf+0x284/0x42c
sp: c00ff1503710
   msr: 90009033
   dar: 60006000
  current = 0xc00ff148
  paca= 0xcfe82d00   softe: 0irq_happened: 0x01
pid   = 1, comm = swapper/8
Linux version 4.11.0-rc2 (sv@sagarika) (gcc version 4.9.4
(Buildroot 2017.02-4-gc28573e) ) #15 SMP Fri Mar 17 19:32:02 IST 2017
enter ? for help
[link register   ] c022ed78 vsnprintf+0x284/0x42c
[c00ff1503710] c022ebb8 vsnprintf+0xc4/0x42c (unreliable)
[c00ff1503800] c022ef40 vscnprintf+0x20/0x44
[c00ff1503830] c00ab61c vprintk_emit+0x94/0x2cc
[c00ff15038a0] c00acc9c vprintk_func+0x60/0x74
[c00ff15038c0] c0619694 printk+0x38/0x4c
[c00ff15038e0] c0224950 kobject_get+0x40/0x60
[c00ff1503950] c022507c kobject_add_internal+0x60/0x2c4
[c00ff15039e0] c0225350 kobject_init_and_add+0x70/0x78
[c00ff1503a60] c053c288 cpuidle_add_sysfs+0x9c/0xe0
[c00ff1503ae0] c053aeac cpuidle_register_device+0xd4/0x12c
[c00ff1503b30] c053b108 cpuidle_register+0x98/0xcc
[c00ff1503bc0] c085eaf0 powernv_processor_idle_init+0x140/0x1e0
[c00ff1503c60] c000cd60 do_one_initcall+0xc0/0x15c
[c00ff1503d20] c0833e84 kernel_init_freeable+0x1a0/0x25c
[c00ff1503dc0] c000d478 kernel_init+0x24/0x12c
[c00ff1503e30] c000b564 ret_from_kernel_thread+0x5c/0x78

This patch fixes the bug by passing correct cpumask from
powernv-cpuidle driver.

Signed-off-by: Vaidyanathan Srinivasan 
Reviewed-by: Gautham R. Shenoy 
Acked-by: Michael Ellerman 
[ rjw: Comment massage ]
Signed-off-by: Rafael J. Wysocki 

Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman 
---
 drivers/cpuidle/cpuidle-powernv.c |   18 ++
 1 file changed, 18 insertions(+)

--- a/drivers/cpuidle/cpuidle-powernv.c
+++ b/drivers/cpuidle/cpuidle-powernv.c
@@ -164,6 +164,24 @@ static int powernv_cpuidle_driver_init(v
drv->state_count += 1;
}
 
+   /*
+* On the PowerNV platform cpu_present may be less than cpu_possible in
+* cases when firmware detects the CPU, but it is not available to the
+* OS.  If CONFIG_HOTPLUG_CPU=n, then such CPUs are not hotplugable at
+* run time and hence cpu_devices are not created for those CPUs by the
+* generic topology_init().
+*
+* drv->cpumask defaults to cpu_possible_mask in
+* __cpuidle_driver_init().  This breaks cpuidle on PowerNV where
+* cpu_devices are not created for CPUs in cpu_possible_mask that
+* cannot be hot-added later at run time.
+*
+* Trying cpuidle_register_device() on a CPU without a cpu_device is
+* incorrect, so pass a correct CPU mask to the generic cpuidle driver.
+*/
+
+   drv->cpumask = (struct cpumask *)cpu_present_mask;
+
return 0;
 }