Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-12-29 14:21:47 +00:00
Code Issues Packages Projects Releases Wiki Activity

powerpc/85xx: fix timebase sync issue when CONFIG_HOTPLUG_CPU=n

Browse Source 
When CONFIG_SMP=y, timebase synchronization is required when the second
kernel is started.

arch/powerpc/kernel/smp.c:
  int __cpu_up(unsigned int cpu, struct task_struct *tidle)
  {
  	...
  	if (smp_ops->give_timebase)
  		smp_ops->give_timebase();
  	...
  }

  void start_secondary(void *unused)
  {
  	...
  	if (smp_ops->take_timebase)
  		smp_ops->take_timebase();
  	...
  }

When CONFIG_HOTPLUG_CPU=n and CONFIG_KEXEC_CORE=n,
 smp_85xx_ops.give_timebase is NULL,
 smp_85xx_ops.take_timebase is NULL,
As a result, the timebase is not synchronized.

Timebase  synchronization does not depend on CONFIG_HOTPLUG_CPU.

Fixes: 56f1ba2807 ("powerpc/mpc85xx: refactor the PM operations")
Cc: stable@vger.kernel.org # v4.6+
Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210929033646.39630-3-nixiaoming@huawei.com
This commit is contained in:
Xiaoming Ni 2021-09-29 11:36:46 +08:00 committed by Michael Ellerman
parent 3c2172c1c4
commit c45361abb9
3 changed files with 13 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
arch/powerpc/platforms/85xx/Makefile
View File

@ -3,7 +3,9 @@
# Makefile for the PowerPC 85xx linux kernel.
#
obj-$(CONFIG_SMP) += smp.o
obj-$(CONFIG_FSL_PMC) += mpc85xx_pm_ops.o
ifneq ($(CONFIG_FSL_CORENET_RCPM),y)
obj-$(CONFIG_SMP) += mpc85xx_pm_ops.o
endif
obj-y += common.o

4
arch/powerpc/platforms/85xx/mpc85xx_pm_ops.c
View File

@ -17,6 +17,7 @@
static struct ccsr_guts __iomem *guts;
#ifdef CONFIG_FSL_PMC
static void mpc85xx_irq_mask(int cpu)
{
@ -49,6 +50,7 @@ static void mpc85xx_cpu_up_prepare(int cpu)
{
}
#endif
static void mpc85xx_freeze_time_base(bool freeze)
{
@ -76,10 +78,12 @@ static const struct of_device_id mpc85xx_smp_guts_ids[] = {
static const struct fsl_pm_ops mpc85xx_pm_ops = {
.freeze_time_base = mpc85xx_freeze_time_base,
#ifdef CONFIG_FSL_PMC
.irq_mask = mpc85xx_irq_mask,
.irq_unmask = mpc85xx_irq_unmask,
.cpu_die = mpc85xx_cpu_die,
.cpu_up_prepare = mpc85xx_cpu_up_prepare,
#endif
};
int __init mpc85xx_setup_pmc(void)

12
arch/powerpc/platforms/85xx/smp.c
View File

@ -40,7 +40,6 @@ struct epapr_spin_table {
u32 pir;
};
#ifdef CONFIG_HOTPLUG_CPU
static u64 timebase;
static int tb_req;
static int tb_valid;
@ -112,6 +111,7 @@ static void mpc85xx_take_timebase(void)
local_irq_restore(flags);
}
#ifdef CONFIG_HOTPLUG_CPU
static void smp_85xx_cpu_offline_self(void)
{
unsigned int cpu = smp_processor_id();
@ -495,21 +495,21 @@ void __init mpc85xx_smp_init(void)
smp_85xx_ops.probe = NULL;
}
#ifdef CONFIG_HOTPLUG_CPU
#ifdef CONFIG_FSL_CORENET_RCPM
/* Assign a value to qoriq_pm_ops on PPC_E500MC */
fsl_rcpm_init();
#endif
#ifdef CONFIG_FSL_PMC
#else
/* Assign a value to qoriq_pm_ops on !PPC_E500MC */
mpc85xx_setup_pmc();
#endif
if (qoriq_pm_ops) {
smp_85xx_ops.give_timebase = mpc85xx_give_timebase;
smp_85xx_ops.take_timebase = mpc85xx_take_timebase;
#ifdef CONFIG_HOTPLUG_CPU
smp_85xx_ops.cpu_offline_self = smp_85xx_cpu_offline_self;
smp_85xx_ops.cpu_die = qoriq_cpu_kill;
}
#endif
}
smp_ops = &smp_85xx_ops;
#ifdef CONFIG_KEXEC_CORE