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authorVaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>2017-03-23 18:22:46 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2017-03-29 23:55:36 +0300
commit293d264f13cbde328d5477f49e3103edbc1dc191 (patch)
tree2e167fa498a1513d37191f916ff5507fdfb81021 /drivers/cpuidle/cpuidle-powernv.c
parentad0a45fd9c14feebd000b6e84189d0edff265170 (diff)
downloadlinux-293d264f13cbde328d5477f49e3103edbc1dc191.tar.xz
cpuidle: powernv: Pass correct drv->cpumask for registration
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 [c000000ff1503490] pc: c00000000022c8bc: string+0x34/0x60 lr: c00000000022ed78: vsnprintf+0x284/0x42c sp: c000000ff1503710 msr: 9000000000009033 dar: 6000000060000000 current = 0xc000000ff1480000 paca = 0xc00000000fe82d00 softe: 0 irq_happened: 0x01 pid = 1, comm = swapper/8 Linux version 4.11.0-rc2 (sv@sagarika) (gcc version 4.9.4 (Buildroot 2017.02-00004-gc28573e) ) #15 SMP Fri Mar 17 19:32:02 IST 2017 enter ? for help [link register ] c00000000022ed78 vsnprintf+0x284/0x42c [c000000ff1503710] c00000000022ebb8 vsnprintf+0xc4/0x42c (unreliable) [c000000ff1503800] c00000000022ef40 vscnprintf+0x20/0x44 [c000000ff1503830] c0000000000ab61c vprintk_emit+0x94/0x2cc [c000000ff15038a0] c0000000000acc9c vprintk_func+0x60/0x74 [c000000ff15038c0] c000000000619694 printk+0x38/0x4c [c000000ff15038e0] c000000000224950 kobject_get+0x40/0x60 [c000000ff1503950] c00000000022507c kobject_add_internal+0x60/0x2c4 [c000000ff15039e0] c000000000225350 kobject_init_and_add+0x70/0x78 [c000000ff1503a60] c00000000053c288 cpuidle_add_sysfs+0x9c/0xe0 [c000000ff1503ae0] c00000000053aeac cpuidle_register_device+0xd4/0x12c [c000000ff1503b30] c00000000053b108 cpuidle_register+0x98/0xcc [c000000ff1503bc0] c00000000085eaf0 powernv_processor_idle_init+0x140/0x1e0 [c000000ff1503c60] c00000000000cd60 do_one_initcall+0xc0/0x15c [c000000ff1503d20] c000000000833e84 kernel_init_freeable+0x1a0/0x25c [c000000ff1503dc0] c00000000000d478 kernel_init+0x24/0x12c [c000000ff1503e30] c00000000000b564 ret_from_kernel_thread+0x5c/0x78 This patch fixes the bug by passing correct cpumask from powernv-cpuidle driver. Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> [ rjw: Comment massage ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpuidle/cpuidle-powernv.c')
-rw-r--r--drivers/cpuidle/cpuidle-powernv.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c
index 370593006f5f..cda8f62d555b 100644
--- a/drivers/cpuidle/cpuidle-powernv.c
+++ b/drivers/cpuidle/cpuidle-powernv.c
@@ -175,6 +175,24 @@ static int powernv_cpuidle_driver_init(void)
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;
}