From 88b3aac6228baaac6a3bcc0808845083b9d9f08f Mon Sep 17 00:00:00 2001 From: Helge Deller Date: Fri, 25 Mar 2022 14:31:08 +0100 Subject: parisc: Implement __cpu_die() and __cpu_disable() for CPU hotplugging Add relevant code to __cpu_die() and __cpu_disable() to finally enable the CPU hotplugging features. Reset the irq count values in smp_callin() to zero before bringing up the CPU. It seems that the firmware may need up to 8 seconds to fully stop a CPU in which no other PDC calls are allowed to be made. Use a timeout __cpu_die() to accommodate for this. Use "chcpu -d 1" to bring CPU1 down, and "chcpu -e 1" to bring it up. Signed-off-by: Helge Deller --- arch/parisc/Kconfig | 1 + arch/parisc/include/asm/smp.h | 9 +--- arch/parisc/kernel/smp.c | 102 +++++++++++++++++++++++++++++++++++------- 3 files changed, 90 insertions(+), 22 deletions(-) (limited to 'arch/parisc') diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig index 590843b8a62e..52e550b45692 100644 --- a/arch/parisc/Kconfig +++ b/arch/parisc/Kconfig @@ -56,6 +56,7 @@ config PARISC select HAVE_ARCH_TRACEHOOK select HAVE_REGS_AND_STACK_ACCESS_API select GENERIC_SCHED_CLOCK + select GENERIC_IRQ_MIGRATION if SMP select HAVE_UNSTABLE_SCHED_CLOCK if SMP select LEGACY_TIMER_TICK select CPU_NO_EFFICIENT_FFS diff --git a/arch/parisc/include/asm/smp.h b/arch/parisc/include/asm/smp.h index 2279ebe5e2da..94d1f21ce99a 100644 --- a/arch/parisc/include/asm/smp.h +++ b/arch/parisc/include/asm/smp.h @@ -44,12 +44,7 @@ static inline void smp_send_all_nop(void) { return; } #define NO_PROC_ID 0xFF /* No processor magic marker */ #define ANY_PROC_ID 0xFF /* Any processor magic marker */ -static inline int __cpu_disable (void) { - return 0; -} -static inline void __cpu_die (unsigned int cpu) { - while(1) - ; -} +int __cpu_disable(void); +void __cpu_die(unsigned int cpu); #endif /* __ASM_SMP_H */ diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c index a32a882a2d58..8c5ea457b6e1 100644 --- a/arch/parisc/kernel/smp.c +++ b/arch/parisc/kernel/smp.c @@ -30,6 +30,7 @@ #include #include #include +#include #include #include @@ -60,8 +61,6 @@ volatile struct task_struct *smp_init_current_idle_task; /* track which CPU is booting */ static volatile int cpu_now_booting; -static int parisc_max_cpus = 1; - static DEFINE_PER_CPU(spinlock_t, ipi_lock); enum ipi_message_type { @@ -269,7 +268,7 @@ void arch_send_call_function_single_ipi(int cpu) /* * Called by secondaries to update state and initialize CPU registers. */ -static void __init +static void smp_cpu_init(int cpunum) { extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */ @@ -309,7 +308,7 @@ smp_cpu_init(int cpunum) * Slaves start using C here. Indirectly called from smp_slave_stext. * Do what start_kernel() and main() do for boot strap processor (aka monarch) */ -void __init smp_callin(unsigned long pdce_proc) +void smp_callin(unsigned long pdce_proc) { int slave_id = cpu_now_booting; @@ -334,11 +333,28 @@ void __init smp_callin(unsigned long pdce_proc) /* * Bring one cpu online. */ -int smp_boot_one_cpu(int cpuid, struct task_struct *idle) +static int smp_boot_one_cpu(int cpuid, struct task_struct *idle) { const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid); long timeout; +#ifdef CONFIG_HOTPLUG_CPU + int i; + + /* reset irq statistics for this CPU */ + memset(&per_cpu(irq_stat, cpuid), 0, sizeof(irq_cpustat_t)); + for (i = 0; i < NR_IRQS; i++) { + struct irq_desc *desc = irq_to_desc(i); + + if (desc && desc->kstat_irqs) + *per_cpu_ptr(desc->kstat_irqs, cpuid) = 0; + } +#endif + + /* wait until last booting CPU has started. */ + while (cpu_now_booting) + ; + /* Let _start know what logical CPU we're booting ** (offset into init_tasks[],cpu_data[]) */ @@ -374,7 +390,6 @@ int smp_boot_one_cpu(int cpuid, struct task_struct *idle) if(cpu_online(cpuid)) { /* Which implies Slave has started up */ cpu_now_booting = 0; - smp_init_current_idle_task = NULL; goto alive ; } udelay(100); @@ -415,25 +430,82 @@ void __init smp_prepare_cpus(unsigned int max_cpus) spin_lock_init(&per_cpu(ipi_lock, cpu)); init_cpu_present(cpumask_of(0)); - - parisc_max_cpus = max_cpus; - if (!max_cpus) - printk(KERN_INFO "SMP mode deactivated.\n"); } -void smp_cpus_done(unsigned int cpu_max) +void __init smp_cpus_done(unsigned int cpu_max) { - return; } int __cpu_up(unsigned int cpu, struct task_struct *tidle) { - if (cpu != 0 && cpu < parisc_max_cpus && smp_boot_one_cpu(cpu, tidle)) - return -ENOSYS; + if (cpu_online(cpu)) + return 0; + + if (num_online_cpus() < setup_max_cpus && smp_boot_one_cpu(cpu, tidle)) + return -EIO; + + return cpu_online(cpu) ? 0 : -EIO; +} + +/* + * __cpu_disable runs on the processor to be shutdown. + */ +int __cpu_disable(void) +{ +#ifdef CONFIG_HOTPLUG_CPU + unsigned int cpu = smp_processor_id(); + + remove_cpu_topology(cpu); + + /* + * Take this CPU offline. Once we clear this, we can't return, + * and we must not schedule until we're ready to give up the cpu. + */ + set_cpu_online(cpu, false); + + disable_percpu_irq(IPI_IRQ); + + irq_migrate_all_off_this_cpu(); + + flush_cache_all_local(); + flush_tlb_all_local(NULL); + + /* disable all irqs, including timer irq */ + local_irq_disable(); + + /* wait for next timer irq ... */ + mdelay(1000/HZ+100); + + /* ... and then clear all pending external irqs */ + set_eiem(0); + mtctl(~0UL, CR_EIRR); + mfctl(CR_EIRR); + mtctl(0, CR_EIRR); +#endif + return 0; +} + +/* + * called on the thread which is asking for a CPU to be shutdown - + * waits until shutdown has completed, or it is timed out. + */ +void __cpu_die(unsigned int cpu) +{ + pdc_cpu_rendezvous_lock(); + + if (!cpu_wait_death(cpu, 5)) { + pr_crit("CPU%u: cpu didn't die\n", cpu); + return; + } + pr_info("CPU%u: is shutting down\n", cpu); + + /* set task's state to interruptible sleep */ + set_current_state(TASK_INTERRUPTIBLE); + schedule_timeout((IS_ENABLED(CONFIG_64BIT) ? 8:2) * HZ); - return cpu_online(cpu) ? 0 : -ENOSYS; + pdc_cpu_rendezvous_unlock(); } #ifdef CONFIG_PROC_FS -- cgit v1.2.3