diff options
Diffstat (limited to 'arch/xtensa')
| -rw-r--r-- | arch/xtensa/Kconfig | 9 | ||||
| -rw-r--r-- | arch/xtensa/include/asm/irq.h | 1 | ||||
| -rw-r--r-- | arch/xtensa/include/asm/smp.h | 9 | ||||
| -rw-r--r-- | arch/xtensa/kernel/head.S | 51 | ||||
| -rw-r--r-- | arch/xtensa/kernel/irq.c | 49 | ||||
| -rw-r--r-- | arch/xtensa/kernel/setup.c | 1 | ||||
| -rw-r--r-- | arch/xtensa/kernel/smp.c | 128 | ||||
| -rw-r--r-- | arch/xtensa/kernel/traps.c | 4 |
8 files changed, 248 insertions, 4 deletions
diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig index 4b09c60b6b30..70a160be3464 100644 --- a/arch/xtensa/Kconfig +++ b/arch/xtensa/Kconfig @@ -140,6 +140,15 @@ config NR_CPUS range 2 32 default "4" +config HOTPLUG_CPU + bool "Enable CPU hotplug support" + depends on SMP + help + Say Y here to allow turning CPUs off and on. CPUs can be + controlled through /sys/devices/system/cpu. + + Say N if you want to disable CPU hotplug. + config MATH_EMULATION bool "Math emulation" help diff --git a/arch/xtensa/include/asm/irq.h b/arch/xtensa/include/asm/irq.h index 7d194d462150..f71f88ea7646 100644 --- a/arch/xtensa/include/asm/irq.h +++ b/arch/xtensa/include/asm/irq.h @@ -45,6 +45,7 @@ static __inline__ int irq_canonicalize(int irq) struct irqaction; struct irq_domain; +void migrate_irqs(void); int xtensa_irq_domain_xlate(const u32 *intspec, unsigned int intsize, unsigned long int_irq, unsigned long ext_irq, unsigned long *out_hwirq, unsigned int *out_type); diff --git a/arch/xtensa/include/asm/smp.h b/arch/xtensa/include/asm/smp.h index 30ac58cc70df..4e43f5643891 100644 --- a/arch/xtensa/include/asm/smp.h +++ b/arch/xtensa/include/asm/smp.h @@ -29,6 +29,15 @@ void ipi_init(void); struct seq_file; void show_ipi_list(struct seq_file *p, int prec); +#ifdef CONFIG_HOTPLUG_CPU + +void __cpu_die(unsigned int cpu); +int __cpu_disable(void); +void cpu_die(void); +void cpu_restart(void); + +#endif /* CONFIG_HOTPLUG_CPU */ + #endif /* CONFIG_SMP */ #endif /* _XTENSA_SMP_H */ diff --git a/arch/xtensa/kernel/head.S b/arch/xtensa/kernel/head.S index 74ec62c892bc..aeeb3cc8a410 100644 --- a/arch/xtensa/kernel/head.S +++ b/arch/xtensa/kernel/head.S @@ -103,7 +103,7 @@ _SetupMMU: ENDPROC(_start) - __INIT + __REF .literal_position ENTRY(_startup) @@ -302,6 +302,55 @@ should_never_return: ENDPROC(_startup) +#ifdef CONFIG_HOTPLUG_CPU + +ENTRY(cpu_restart) + +#if XCHAL_DCACHE_IS_WRITEBACK + ___flush_invalidate_dcache_all a2 a3 +#else + ___invalidate_dcache_all a2 a3 +#endif + memw + movi a2, CCON # MX External Register to Configure Cache + movi a3, 0 + wer a3, a2 + extw + + rsr a0, prid + neg a2, a0 + movi a3, cpu_start_id + s32i a2, a3, 0 +#if XCHAL_DCACHE_IS_WRITEBACK + dhwbi a3, 0 +#endif +1: + l32i a2, a3, 0 + dhi a3, 0 + bne a2, a0, 1b + + /* + * Initialize WB, WS, and clear PS.EXCM (to allow loop instructions). + * Set Interrupt Level just below XCHAL_DEBUGLEVEL to allow + * xt-gdb to single step via DEBUG exceptions received directly + * by ocd. + */ + movi a1, 1 + movi a0, 0 + wsr a1, windowstart + wsr a0, windowbase + rsync + + movi a1, LOCKLEVEL + wsr a1, ps + rsync + + j _startup + +ENDPROC(cpu_restart) + +#endif /* CONFIG_HOTPLUG_CPU */ + /* * DATA section */ diff --git a/arch/xtensa/kernel/irq.c b/arch/xtensa/kernel/irq.c index fad9e0059765..482868a2de6e 100644 --- a/arch/xtensa/kernel/irq.c +++ b/arch/xtensa/kernel/irq.c @@ -153,3 +153,52 @@ void __init init_IRQ(void) #endif variant_init_irq(); } + +#ifdef CONFIG_HOTPLUG_CPU +static void route_irq(struct irq_data *data, unsigned int irq, unsigned int cpu) +{ + struct irq_desc *desc = irq_to_desc(irq); + struct irq_chip *chip = irq_data_get_irq_chip(data); + unsigned long flags; + + raw_spin_lock_irqsave(&desc->lock, flags); + if (chip->irq_set_affinity) + chip->irq_set_affinity(data, cpumask_of(cpu), false); + raw_spin_unlock_irqrestore(&desc->lock, flags); +} + +/* + * The CPU has been marked offline. Migrate IRQs off this CPU. If + * the affinity settings do not allow other CPUs, force them onto any + * available CPU. + */ +void migrate_irqs(void) +{ + unsigned int i, cpu = smp_processor_id(); + struct irq_desc *desc; + + for_each_irq_desc(i, desc) { + struct irq_data *data = irq_desc_get_irq_data(desc); + unsigned int newcpu; + + if (irqd_is_per_cpu(data)) + continue; + + if (!cpumask_test_cpu(cpu, data->affinity)) + continue; + + newcpu = cpumask_any_and(data->affinity, cpu_online_mask); + + if (newcpu >= nr_cpu_ids) { + pr_info_ratelimited("IRQ%u no longer affine to CPU%u\n", + i, cpu); + + cpumask_setall(data->affinity); + newcpu = cpumask_any_and(data->affinity, + cpu_online_mask); + } + + route_irq(data, i, newcpu); + } +} +#endif /* CONFIG_HOTPLUG_CPU */ diff --git a/arch/xtensa/kernel/setup.c b/arch/xtensa/kernel/setup.c index dfd8f52c05d8..d21bfa7a28e0 100644 --- a/arch/xtensa/kernel/setup.c +++ b/arch/xtensa/kernel/setup.c @@ -527,6 +527,7 @@ static int __init topology_init(void) for_each_possible_cpu(i) { struct cpu *cpu = &per_cpu(cpu_data, i); + cpu->hotpluggable = !!i; register_cpu(cpu, i); } diff --git a/arch/xtensa/kernel/smp.c b/arch/xtensa/kernel/smp.c index 46bdd142a07d..1c7a209795e8 100644 --- a/arch/xtensa/kernel/smp.c +++ b/arch/xtensa/kernel/smp.c @@ -40,6 +40,11 @@ # endif #endif +static void system_invalidate_dcache_range(unsigned long start, + unsigned long size); +static void system_flush_invalidate_dcache_range(unsigned long start, + unsigned long size); + /* IPI (Inter Process Interrupt) */ #define IPI_IRQ 0 @@ -106,7 +111,7 @@ void __init smp_cpus_done(unsigned int max_cpus) static int boot_secondary_processors = 1; /* Set with xt-gdb via .xt-gdb */ static DECLARE_COMPLETION(cpu_running); -void __init secondary_start_kernel(void) +void secondary_start_kernel(void) { struct mm_struct *mm = &init_mm; unsigned int cpu = smp_processor_id(); @@ -174,6 +179,9 @@ static void mx_cpu_stop(void *p) __func__, cpu, run_stall_mask, get_er(MPSCORE)); } +#ifdef CONFIG_HOTPLUG_CPU +unsigned long cpu_start_id __cacheline_aligned; +#endif unsigned long cpu_start_ccount; static int boot_secondary(unsigned int cpu, struct task_struct *ts) @@ -182,6 +190,11 @@ static int boot_secondary(unsigned int cpu, struct task_struct *ts) unsigned long ccount; int i; +#ifdef CONFIG_HOTPLUG_CPU + cpu_start_id = cpu; + system_flush_invalidate_dcache_range( + (unsigned long)&cpu_start_id, sizeof(cpu_start_id)); +#endif smp_call_function_single(0, mx_cpu_start, (void *)cpu, 1); for (i = 0; i < 2; ++i) { @@ -234,6 +247,85 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle) return ret; } +#ifdef CONFIG_HOTPLUG_CPU + +/* + * __cpu_disable runs on the processor to be shutdown. + */ +int __cpu_disable(void) +{ + unsigned int cpu = smp_processor_id(); + + /* + * 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); + + /* + * OK - migrate IRQs away from this CPU + */ + migrate_irqs(); + + /* + * Flush user cache and TLB mappings, and then remove this CPU + * from the vm mask set of all processes. + */ + local_flush_cache_all(); + local_flush_tlb_all(); + invalidate_page_directory(); + + clear_tasks_mm_cpumask(cpu); + + return 0; +} + +static void platform_cpu_kill(unsigned int cpu) +{ + smp_call_function_single(0, mx_cpu_stop, (void *)cpu, true); +} + +/* + * 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) +{ + unsigned long timeout = jiffies + msecs_to_jiffies(1000); + while (time_before(jiffies, timeout)) { + system_invalidate_dcache_range((unsigned long)&cpu_start_id, + sizeof(cpu_start_id)); + if (cpu_start_id == -cpu) { + platform_cpu_kill(cpu); + return; + } + } + pr_err("CPU%u: unable to kill\n", cpu); +} + +void arch_cpu_idle_dead(void) +{ + cpu_die(); +} +/* + * Called from the idle thread for the CPU which has been shutdown. + * + * Note that we disable IRQs here, but do not re-enable them + * before returning to the caller. This is also the behaviour + * of the other hotplug-cpu capable cores, so presumably coming + * out of idle fixes this. + */ +void __ref cpu_die(void) +{ + idle_task_exit(); + local_irq_disable(); + __asm__ __volatile__( + " movi a2, cpu_restart\n" + " jx a2\n"); +} + +#endif /* CONFIG_HOTPLUG_CPU */ + enum ipi_msg_type { IPI_RESCHEDULE = 0, IPI_CALL_FUNC, @@ -463,3 +555,37 @@ void flush_icache_range(unsigned long start, unsigned long end) }; on_each_cpu(ipi_flush_icache_range, &fd, 1); } + +/* ------------------------------------------------------------------------- */ + +static void ipi_invalidate_dcache_range(void *arg) +{ + struct flush_data *fd = arg; + __invalidate_dcache_range(fd->addr1, fd->addr2); +} + +static void system_invalidate_dcache_range(unsigned long start, + unsigned long size) +{ + struct flush_data fd = { + .addr1 = start, + .addr2 = size, + }; + on_each_cpu(ipi_invalidate_dcache_range, &fd, 1); +} + +static void ipi_flush_invalidate_dcache_range(void *arg) +{ + struct flush_data *fd = arg; + __flush_invalidate_dcache_range(fd->addr1, fd->addr2); +} + +static void system_flush_invalidate_dcache_range(unsigned long start, + unsigned long size) +{ + struct flush_data fd = { + .addr1 = start, + .addr2 = size, + }; + on_each_cpu(ipi_flush_invalidate_dcache_range, &fd, 1); +} diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c index 3c0ff5746fe2..eebbfd8c26fc 100644 --- a/arch/xtensa/kernel/traps.c +++ b/arch/xtensa/kernel/traps.c @@ -332,7 +332,7 @@ void * __init trap_set_handler(int cause, void *handler) } -static void __init trap_init_excsave(void) +static void trap_init_excsave(void) { unsigned long excsave1 = (unsigned long)this_cpu_ptr(exc_table); __asm__ __volatile__("wsr %0, excsave1\n" : : "a" (excsave1)); @@ -384,7 +384,7 @@ void __init trap_init(void) } #ifdef CONFIG_SMP -void __init secondary_trap_init(void) +void secondary_trap_init(void) { trap_init_excsave(); } |