xtensa: implement CPU hotplug
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> Signed-off-by: Chris Zankel <chris@zankel.net>
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f615136c06
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49b424feda
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@ -140,6 +140,15 @@ config NR_CPUS
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range 2 32
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default "4"
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config HOTPLUG_CPU
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bool "Enable CPU hotplug support"
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depends on SMP
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help
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Say Y here to allow turning CPUs off and on. CPUs can be
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controlled through /sys/devices/system/cpu.
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Say N if you want to disable CPU hotplug.
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config MATH_EMULATION
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bool "Math emulation"
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help
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@ -45,6 +45,7 @@ static __inline__ int irq_canonicalize(int irq)
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struct irqaction;
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struct irq_domain;
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void migrate_irqs(void);
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int xtensa_irq_domain_xlate(const u32 *intspec, unsigned int intsize,
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unsigned long int_irq, unsigned long ext_irq,
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unsigned long *out_hwirq, unsigned int *out_type);
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@ -29,6 +29,15 @@ void ipi_init(void);
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struct seq_file;
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void show_ipi_list(struct seq_file *p, int prec);
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#ifdef CONFIG_HOTPLUG_CPU
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void __cpu_die(unsigned int cpu);
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int __cpu_disable(void);
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void cpu_die(void);
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void cpu_restart(void);
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#endif /* CONFIG_HOTPLUG_CPU */
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#endif /* CONFIG_SMP */
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#endif /* _XTENSA_SMP_H */
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@ -103,7 +103,7 @@ _SetupMMU:
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ENDPROC(_start)
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__INIT
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__REF
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.literal_position
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ENTRY(_startup)
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@ -302,6 +302,55 @@ should_never_return:
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ENDPROC(_startup)
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#ifdef CONFIG_HOTPLUG_CPU
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ENTRY(cpu_restart)
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#if XCHAL_DCACHE_IS_WRITEBACK
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___flush_invalidate_dcache_all a2 a3
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#else
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___invalidate_dcache_all a2 a3
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#endif
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memw
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movi a2, CCON # MX External Register to Configure Cache
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movi a3, 0
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wer a3, a2
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extw
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rsr a0, prid
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neg a2, a0
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movi a3, cpu_start_id
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s32i a2, a3, 0
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#if XCHAL_DCACHE_IS_WRITEBACK
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dhwbi a3, 0
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#endif
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1:
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l32i a2, a3, 0
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dhi a3, 0
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bne a2, a0, 1b
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/*
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* Initialize WB, WS, and clear PS.EXCM (to allow loop instructions).
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* Set Interrupt Level just below XCHAL_DEBUGLEVEL to allow
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* xt-gdb to single step via DEBUG exceptions received directly
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* by ocd.
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*/
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movi a1, 1
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movi a0, 0
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wsr a1, windowstart
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wsr a0, windowbase
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rsync
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movi a1, LOCKLEVEL
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wsr a1, ps
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rsync
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j _startup
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ENDPROC(cpu_restart)
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#endif /* CONFIG_HOTPLUG_CPU */
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/*
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* DATA section
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*/
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@ -153,3 +153,52 @@ void __init init_IRQ(void)
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#endif
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variant_init_irq();
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}
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#ifdef CONFIG_HOTPLUG_CPU
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static void route_irq(struct irq_data *data, unsigned int irq, unsigned int cpu)
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{
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struct irq_desc *desc = irq_to_desc(irq);
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struct irq_chip *chip = irq_data_get_irq_chip(data);
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unsigned long flags;
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raw_spin_lock_irqsave(&desc->lock, flags);
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if (chip->irq_set_affinity)
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chip->irq_set_affinity(data, cpumask_of(cpu), false);
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raw_spin_unlock_irqrestore(&desc->lock, flags);
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}
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/*
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* The CPU has been marked offline. Migrate IRQs off this CPU. If
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* the affinity settings do not allow other CPUs, force them onto any
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* available CPU.
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*/
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void migrate_irqs(void)
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{
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unsigned int i, cpu = smp_processor_id();
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struct irq_desc *desc;
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for_each_irq_desc(i, desc) {
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struct irq_data *data = irq_desc_get_irq_data(desc);
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unsigned int newcpu;
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if (irqd_is_per_cpu(data))
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continue;
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if (!cpumask_test_cpu(cpu, data->affinity))
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continue;
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newcpu = cpumask_any_and(data->affinity, cpu_online_mask);
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if (newcpu >= nr_cpu_ids) {
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pr_info_ratelimited("IRQ%u no longer affine to CPU%u\n",
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i, cpu);
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cpumask_setall(data->affinity);
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newcpu = cpumask_any_and(data->affinity,
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cpu_online_mask);
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}
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route_irq(data, i, newcpu);
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}
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}
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#endif /* CONFIG_HOTPLUG_CPU */
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@ -527,6 +527,7 @@ static int __init topology_init(void)
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for_each_possible_cpu(i) {
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struct cpu *cpu = &per_cpu(cpu_data, i);
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cpu->hotpluggable = !!i;
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register_cpu(cpu, i);
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}
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@ -40,6 +40,11 @@
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# endif
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#endif
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static void system_invalidate_dcache_range(unsigned long start,
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unsigned long size);
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static void system_flush_invalidate_dcache_range(unsigned long start,
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unsigned long size);
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/* IPI (Inter Process Interrupt) */
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#define IPI_IRQ 0
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@ -106,7 +111,7 @@ void __init smp_cpus_done(unsigned int max_cpus)
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static int boot_secondary_processors = 1; /* Set with xt-gdb via .xt-gdb */
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static DECLARE_COMPLETION(cpu_running);
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void __init secondary_start_kernel(void)
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void secondary_start_kernel(void)
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{
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struct mm_struct *mm = &init_mm;
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unsigned int cpu = smp_processor_id();
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@ -174,6 +179,9 @@ static void mx_cpu_stop(void *p)
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__func__, cpu, run_stall_mask, get_er(MPSCORE));
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}
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#ifdef CONFIG_HOTPLUG_CPU
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unsigned long cpu_start_id __cacheline_aligned;
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#endif
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unsigned long cpu_start_ccount;
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static int boot_secondary(unsigned int cpu, struct task_struct *ts)
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@ -182,6 +190,11 @@ static int boot_secondary(unsigned int cpu, struct task_struct *ts)
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unsigned long ccount;
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int i;
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#ifdef CONFIG_HOTPLUG_CPU
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cpu_start_id = cpu;
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system_flush_invalidate_dcache_range(
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(unsigned long)&cpu_start_id, sizeof(cpu_start_id));
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#endif
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smp_call_function_single(0, mx_cpu_start, (void *)cpu, 1);
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for (i = 0; i < 2; ++i) {
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@ -234,6 +247,85 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
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return ret;
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}
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#ifdef CONFIG_HOTPLUG_CPU
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/*
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* __cpu_disable runs on the processor to be shutdown.
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*/
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int __cpu_disable(void)
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{
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unsigned int cpu = smp_processor_id();
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/*
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* Take this CPU offline. Once we clear this, we can't return,
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* and we must not schedule until we're ready to give up the cpu.
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*/
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set_cpu_online(cpu, false);
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/*
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* OK - migrate IRQs away from this CPU
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*/
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migrate_irqs();
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/*
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* Flush user cache and TLB mappings, and then remove this CPU
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* from the vm mask set of all processes.
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*/
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local_flush_cache_all();
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local_flush_tlb_all();
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invalidate_page_directory();
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clear_tasks_mm_cpumask(cpu);
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return 0;
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}
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static void platform_cpu_kill(unsigned int cpu)
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{
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smp_call_function_single(0, mx_cpu_stop, (void *)cpu, true);
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}
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/*
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* called on the thread which is asking for a CPU to be shutdown -
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* waits until shutdown has completed, or it is timed out.
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*/
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void __cpu_die(unsigned int cpu)
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{
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unsigned long timeout = jiffies + msecs_to_jiffies(1000);
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while (time_before(jiffies, timeout)) {
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system_invalidate_dcache_range((unsigned long)&cpu_start_id,
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sizeof(cpu_start_id));
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if (cpu_start_id == -cpu) {
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platform_cpu_kill(cpu);
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return;
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}
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}
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pr_err("CPU%u: unable to kill\n", cpu);
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}
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void arch_cpu_idle_dead(void)
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{
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cpu_die();
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}
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/*
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* Called from the idle thread for the CPU which has been shutdown.
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*
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* Note that we disable IRQs here, but do not re-enable them
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* before returning to the caller. This is also the behaviour
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* of the other hotplug-cpu capable cores, so presumably coming
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* out of idle fixes this.
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*/
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void __ref cpu_die(void)
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{
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idle_task_exit();
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local_irq_disable();
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__asm__ __volatile__(
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" movi a2, cpu_restart\n"
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" jx a2\n");
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}
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#endif /* CONFIG_HOTPLUG_CPU */
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enum ipi_msg_type {
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IPI_RESCHEDULE = 0,
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IPI_CALL_FUNC,
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@ -463,3 +555,37 @@ void flush_icache_range(unsigned long start, unsigned long end)
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};
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on_each_cpu(ipi_flush_icache_range, &fd, 1);
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}
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/* ------------------------------------------------------------------------- */
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static void ipi_invalidate_dcache_range(void *arg)
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{
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struct flush_data *fd = arg;
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__invalidate_dcache_range(fd->addr1, fd->addr2);
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}
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static void system_invalidate_dcache_range(unsigned long start,
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unsigned long size)
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{
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struct flush_data fd = {
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.addr1 = start,
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.addr2 = size,
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};
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on_each_cpu(ipi_invalidate_dcache_range, &fd, 1);
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}
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static void ipi_flush_invalidate_dcache_range(void *arg)
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{
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struct flush_data *fd = arg;
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__flush_invalidate_dcache_range(fd->addr1, fd->addr2);
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}
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static void system_flush_invalidate_dcache_range(unsigned long start,
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unsigned long size)
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{
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struct flush_data fd = {
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.addr1 = start,
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.addr2 = size,
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};
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on_each_cpu(ipi_flush_invalidate_dcache_range, &fd, 1);
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}
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@ -332,7 +332,7 @@ void * __init trap_set_handler(int cause, void *handler)
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}
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static void __init trap_init_excsave(void)
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static void trap_init_excsave(void)
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{
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unsigned long excsave1 = (unsigned long)this_cpu_ptr(exc_table);
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__asm__ __volatile__("wsr %0, excsave1\n" : : "a" (excsave1));
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}
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#ifdef CONFIG_SMP
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void __init secondary_trap_init(void)
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void secondary_trap_init(void)
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{
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trap_init_excsave();
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}
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