When CONFIG_SMP=y, timebase synchronization is required for mpc8572 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.
test code: for i in $(seq 1 3); do taskset 1 date; taskset 2 date; sleep 1; echo;done log: Sat Sep 25 18:50:00 CST 2021 Sat Sep 25 19:07:47 CST 2021
Sat Sep 25 18:50:01 CST 2021 Sat Sep 25 19:07:48 CST 2021
Sat Sep 25 18:50:02 CST 2021 Sat Sep 25 19:07:49 CST 2021
Code snippet about give_timebase and take_timebase assignments: arch/powerpc/platforms/85xx/smp.c: #ifdef CONFIG_HOTPLUG_CPU #ifdef CONFIG_FSL_CORENET_RCPM fsl_rcpm_init(); #endif #ifdef CONFIG_FSL_PMC mpc85xx_setup_pmc(); #endif if (qoriq_pm_ops) { smp_85xx_ops.give_timebase = mpc85xx_give_timebase; smp_85xx_ops.take_timebase = mpc85xx_take_timebase;
config dependency: FSL_CORENET_RCPM depends on the PPC_E500MC. FSL_PMC depends on SUSPEND. SUSPEND depends on ARCH_SUSPEND_POSSIBLE. ARCH_SUSPEND_POSSIBLE depends on !PPC_E500MC.
CONFIG_HOTPLUG_CPU and CONFIG_FSL_PMC require the timebase function, but the timebase should not depend on CONFIG_HOTPLUG_CPU and CONFIG_FSL_PMC. Therefore, adjust the macro control range. Ensure that the corresponding timebase hook function is not empty when the dtsi node is configured.
----- changes in v2: 1. add new patch: "powerpc:85xx:Fix oops when mpc85xx_smp_guts_ids node cannot be found" 2. Using !CONFIG_FSL_CORENET_RCPM to manage the timebase code of !PPC_E500MC
v1: https://lore.kernel.org/lkml/20210926025144.55674-1-nixiaoming@huawei.com ------
Xiaoming Ni (2): powerpc:85xx:Fix oops when mpc85xx_smp_guts_ids node cannot be found powerpc:85xx: fix timebase sync issue when CONFIG_HOTPLUG_CPU=n
arch/powerpc/platforms/85xx/Makefile | 4 +++- arch/powerpc/platforms/85xx/mpc85xx_pm_ops.c | 7 +++++-- arch/powerpc/platforms/85xx/smp.c | 12 ++++++------ 3 files changed, 14 insertions(+), 9 deletions(-)
When the field described in mpc85xx_smp_guts_ids[] is not configured in dtb, the mpc85xx_setup_pmc() does not assign a value to the "guts" variable. As a result, the oops is triggered when mpc85xx_freeze_time_base() is executed.
Fixes:56f1ba280719 ("powerpc/mpc85xx: refactor the PM operations") Cc: stable@vger.kernel.org #v4.6 Signed-off-by: Xiaoming Ni nixiaoming@huawei.com --- arch/powerpc/platforms/85xx/mpc85xx_pm_ops.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/powerpc/platforms/85xx/mpc85xx_pm_ops.c b/arch/powerpc/platforms/85xx/mpc85xx_pm_ops.c index 7c0133f558d0..ffa8a7a6a2db 100644 --- a/arch/powerpc/platforms/85xx/mpc85xx_pm_ops.c +++ b/arch/powerpc/platforms/85xx/mpc85xx_pm_ops.c @@ -94,9 +94,8 @@ int __init mpc85xx_setup_pmc(void) pr_err("Could not map guts node address\n"); return -ENOMEM; } + qoriq_pm_ops = &mpc85xx_pm_ops; }
- qoriq_pm_ops = &mpc85xx_pm_ops; - return 0; }
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 --- 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(-)
diff --git a/arch/powerpc/platforms/85xx/Makefile b/arch/powerpc/platforms/85xx/Makefile index 60e4e97a929d..260fbad7967b 100644 --- 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
diff --git a/arch/powerpc/platforms/85xx/mpc85xx_pm_ops.c b/arch/powerpc/platforms/85xx/mpc85xx_pm_ops.c index ffa8a7a6a2db..4a8af80011a6 100644 --- 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 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) diff --git a/arch/powerpc/platforms/85xx/smp.c b/arch/powerpc/platforms/85xx/smp.c index c6df294054fe..83f4a6389a28 100644 --- 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
On Wed, 29 Sep 2021 11:36:44 +0800, Xiaoming Ni wrote:
When CONFIG_SMP=y, timebase synchronization is required for mpc8572 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(); ... }
[...]
Applied to powerpc/next.
[1/2] powerpc:85xx:Fix oops when mpc85xx_smp_guts_ids node cannot be found https://git.kernel.org/powerpc/c/3c2172c1c47b4079c29f0e6637d764a99355ebcd [2/2] powerpc:85xx: fix timebase sync issue when CONFIG_HOTPLUG_CPU=n https://git.kernel.org/powerpc/c/c45361abb9185b1e172bd75eff51ad5f601ccae4
cheers
linux-stable-mirror@lists.linaro.org
-
Michael Ellerman -
Xiaoming Ni