From: Xiaoming Ni nixiaoming@huawei.com
commit c45361abb9185b1e172bd75eff51ad5f601ccae4 upstream.
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: 56f1ba280719 ("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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/powerpc/platforms/85xx/Makefile | 4 +++- arch/powerpc/platforms/85xx/mpc85xx_pm_ops.c | 4 ++++ arch/powerpc/platforms/85xx/smp.c | 12 ++++++------ 3 files changed, 13 insertions(+), 7 deletions(-)
--- a/arch/powerpc/platforms/85xx/Makefile +++ b/arch/powerpc/platforms/85xx/Makefile @@ -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
--- a/arch/powerpc/platforms/85xx/mpc85xx_pm_ops.c +++ b/arch/powerpc/platforms/85xx/mpc85xx_pm_ops.c @@ -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 c {
} +#endif
static void mpc85xx_freeze_time_base(bool freeze) { @@ -76,10 +78,12 @@ static const struct of_device_id mpc85xx
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) --- a/arch/powerpc/platforms/85xx/smp.c +++ b/arch/powerpc/platforms/85xx/smp.c @@ -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