diff options
Diffstat (limited to 'arch/arm/kernel/smp.c')
| -rw-r--r-- | arch/arm/kernel/smp.c | 686 |
1 files changed, 686 insertions, 0 deletions
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c new file mode 100644 index 00000000..24cdba4e --- /dev/null +++ b/arch/arm/kernel/smp.c @@ -0,0 +1,686 @@ +/* + * linux/arch/arm/kernel/smp.c + * + * Copyright (C) 2002 ARM Limited, All Rights Reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#include <linux/module.h> +#include <linux/delay.h> +#include <linux/init.h> +#include <linux/spinlock.h> +#include <linux/sched.h> +#include <linux/interrupt.h> +#include <linux/cache.h> +#include <linux/profile.h> +#include <linux/errno.h> +#include <linux/ftrace.h> +#include <linux/mm.h> +#include <linux/err.h> +#include <linux/cpu.h> +#include <linux/smp.h> +#include <linux/seq_file.h> +#include <linux/irq.h> +#include <linux/percpu.h> +#include <linux/clockchips.h> +#include <linux/completion.h> + +#include <asm/atomic.h> +#include <asm/cacheflush.h> +#include <asm/cpu.h> +#include <asm/cputype.h> +#include <asm/mmu_context.h> +#include <asm/pgtable.h> +#include <asm/pgalloc.h> +#include <asm/processor.h> +#include <asm/sections.h> +#include <asm/tlbflush.h> +#include <asm/ptrace.h> +#include <asm/localtimer.h> + +/* + * as from 2.5, kernels no longer have an init_tasks structure + * so we need some other way of telling a new secondary core + * where to place its SVC stack + */ +struct secondary_data secondary_data; + +enum ipi_msg_type { + IPI_TIMER = 2, + IPI_RESCHEDULE, + IPI_CALL_FUNC, + IPI_CALL_FUNC_SINGLE, + IPI_CPU_STOP, + IPI_CPU_BACKTRACE, +}; + +static DECLARE_COMPLETION(cpu_running); + +int __cpuinit __cpu_up(unsigned int cpu) +{ + struct cpuinfo_arm *ci = &per_cpu(cpu_data, cpu); + struct task_struct *idle = ci->idle; + pgd_t *pgd; + int ret; + + /* + * Spawn a new process manually, if not already done. + * Grab a pointer to its task struct so we can mess with it + */ + if (!idle) { + idle = fork_idle(cpu); + if (IS_ERR(idle)) { + printk(KERN_ERR "CPU%u: fork() failed\n", cpu); + return PTR_ERR(idle); + } + ci->idle = idle; + } else { + /* + * Since this idle thread is being re-used, call + * init_idle() to reinitialize the thread structure. + */ + init_idle(idle, cpu); + } + + /* + * Allocate initial page tables to allow the new CPU to + * enable the MMU safely. This essentially means a set + * of our "standard" page tables, with the addition of + * a 1:1 mapping for the physical address of the kernel. + */ + pgd = pgd_alloc(&init_mm); + if (!pgd) + return -ENOMEM; + + if (PHYS_OFFSET != PAGE_OFFSET) { +#ifndef CONFIG_HOTPLUG_CPU + identity_mapping_add(pgd, __pa(__init_begin), __pa(__init_end)); +#endif + identity_mapping_add(pgd, __pa(_stext), __pa(_etext)); + identity_mapping_add(pgd, __pa(_sdata), __pa(_edata)); + } + + /* + * We need to tell the secondary core where to find + * its stack and the page tables. + */ + secondary_data.stack = task_stack_page(idle) + THREAD_START_SP; + secondary_data.pgdir = virt_to_phys(pgd); + secondary_data.swapper_pg_dir = virt_to_phys(swapper_pg_dir); + __cpuc_flush_dcache_area(&secondary_data, sizeof(secondary_data)); + outer_clean_range(__pa(&secondary_data), __pa(&secondary_data + 1)); + + /* + * Now bring the CPU into our world. + */ + ret = boot_secondary(cpu, idle); + if (ret == 0) { + /* + * CPU was successfully started, wait for it + * to come online or time out. + */ + wait_for_completion_timeout(&cpu_running, + msecs_to_jiffies(1000)); + + if (!cpu_online(cpu)) { + pr_crit("CPU%u: failed to come online\n", cpu); + ret = -EIO; + } + } else { + pr_err("CPU%u: failed to boot: %d\n", cpu, ret); + } + + secondary_data.stack = NULL; + secondary_data.pgdir = 0; + + if (PHYS_OFFSET != PAGE_OFFSET) { +#ifndef CONFIG_HOTPLUG_CPU + identity_mapping_del(pgd, __pa(__init_begin), __pa(__init_end)); +#endif + identity_mapping_del(pgd, __pa(_stext), __pa(_etext)); + identity_mapping_del(pgd, __pa(_sdata), __pa(_edata)); + } + + pgd_free(&init_mm, pgd); + + return ret; +} + +#ifdef CONFIG_HOTPLUG_CPU +static void percpu_timer_stop(void); + +/* + * __cpu_disable runs on the processor to be shutdown. + */ +int __cpu_disable(void) +{ + unsigned int cpu = smp_processor_id(); + struct task_struct *p; + int ret; + + ret = platform_cpu_disable(cpu); + if (ret) + return ret; + + /* + * 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(); + + /* + * Stop the local timer for this CPU. + */ + percpu_timer_stop(); + + /* + * Flush user cache and TLB mappings, and then remove this CPU + * from the vm mask set of all processes. + */ + flush_cache_all(); + local_flush_tlb_all(); + + read_lock(&tasklist_lock); + for_each_process(p) { + if (p->mm) + cpumask_clear_cpu(cpu, mm_cpumask(p->mm)); + } + read_unlock(&tasklist_lock); + + return 0; +} + +static DECLARE_COMPLETION(cpu_died); + +/* + * 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) +{ + if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) { + pr_err("CPU%u: cpu didn't die\n", cpu); + return; + } + printk(KERN_NOTICE "CPU%u: shutdown\n", cpu); + + if (!platform_cpu_kill(cpu)) + printk("CPU%u: unable to kill\n", cpu); +} + +/* + * 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) +{ + unsigned int cpu = smp_processor_id(); + + idle_task_exit(); + + local_irq_disable(); + mb(); + + /* Tell __cpu_die() that this CPU is now safe to dispose of */ + complete(&cpu_died); + + /* + * actual CPU shutdown procedure is at least platform (if not + * CPU) specific. + */ + platform_cpu_die(cpu); + + /* + * Do not return to the idle loop - jump back to the secondary + * cpu initialisation. There's some initialisation which needs + * to be repeated to undo the effects of taking the CPU offline. + */ + __asm__("mov sp, %0\n" + " mov fp, #0\n" + " b secondary_start_kernel" + : + : "r" (task_stack_page(current) + THREAD_SIZE - 8)); +} +#endif /* CONFIG_HOTPLUG_CPU */ + +/* + * Called by both boot and secondaries to move global data into + * per-processor storage. + */ +static void __cpuinit smp_store_cpu_info(unsigned int cpuid) +{ + struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid); + + cpu_info->loops_per_jiffy = loops_per_jiffy; +} + +/* + * This is the secondary CPU boot entry. We're using this CPUs + * idle thread stack, but a set of temporary page tables. + */ +asmlinkage void __cpuinit secondary_start_kernel(void) +{ + struct mm_struct *mm = &init_mm; + unsigned int cpu = smp_processor_id(); + + /* + * All kernel threads share the same mm context; grab a + * reference and switch to it. + */ + atomic_inc(&mm->mm_count); + current->active_mm = mm; + cpumask_set_cpu(cpu, mm_cpumask(mm)); + cpu_switch_mm(mm->pgd, mm); + enter_lazy_tlb(mm, current); + local_flush_tlb_all(); + + printk("CPU%u: Booted secondary processor\n", cpu); + + cpu_init(); + preempt_disable(); + trace_hardirqs_off(); + + /* + * Give the platform a chance to do its own initialisation. + */ + platform_secondary_init(cpu); + + notify_cpu_starting(cpu); + + calibrate_delay(); + + smp_store_cpu_info(cpu); + + /* + * OK, now it's safe to let the boot CPU continue. Wait for + * the CPU migration code to notice that the CPU is online + * before we continue - which happens after __cpu_up returns. + */ + set_cpu_online(cpu, true); + complete(&cpu_running); + + /* + * Setup the percpu timer for this CPU. + */ + percpu_timer_setup(); + + local_irq_enable(); + local_fiq_enable(); + + /* + * OK, it's off to the idle thread for us + */ + cpu_idle(); +} + +void __init smp_cpus_done(unsigned int max_cpus) +{ + int cpu; + unsigned long bogosum = 0; + + for_each_online_cpu(cpu) + bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy; + + printk(KERN_INFO "SMP: Total of %d processors activated " + "(%lu.%02lu BogoMIPS).\n", + num_online_cpus(), + bogosum / (500000/HZ), + (bogosum / (5000/HZ)) % 100); +} + +void __init smp_prepare_boot_cpu(void) +{ + unsigned int cpu = smp_processor_id(); + + per_cpu(cpu_data, cpu).idle = current; +} + +void __init smp_prepare_cpus(unsigned int max_cpus) +{ + unsigned int ncores = num_possible_cpus(); + + smp_store_cpu_info(smp_processor_id()); + + /* + * are we trying to boot more cores than exist? + */ + if (max_cpus > ncores) + max_cpus = ncores; + + if (max_cpus > 1) { + /* + * Enable the local timer or broadcast device for the + * boot CPU, but only if we have more than one CPU. + */ + percpu_timer_setup(); + + /* + * Initialise the SCU if there are more than one CPU + * and let them know where to start. + */ + platform_smp_prepare_cpus(max_cpus); + } +} + +static void (*smp_cross_call)(const struct cpumask *, unsigned int); + +void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int)) +{ + smp_cross_call = fn; +} + +void arch_send_call_function_ipi_mask(const struct cpumask *mask) +{ + smp_cross_call(mask, IPI_CALL_FUNC); +} + +void arch_send_call_function_single_ipi(int cpu) +{ + smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE); +} + +static const char *ipi_types[NR_IPI] = { +#define S(x,s) [x - IPI_TIMER] = s + S(IPI_TIMER, "Timer broadcast interrupts"), + S(IPI_RESCHEDULE, "Rescheduling interrupts"), + S(IPI_CALL_FUNC, "Function call interrupts"), + S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"), + S(IPI_CPU_STOP, "CPU stop interrupts"), + S(IPI_CPU_BACKTRACE, "CPU backtrace"), +}; + +void show_ipi_list(struct seq_file *p, int prec) +{ + unsigned int cpu, i; + + for (i = 0; i < NR_IPI; i++) { + seq_printf(p, "%*s%u: ", prec - 1, "IPI", i); + + for_each_present_cpu(cpu) + seq_printf(p, "%10u ", + __get_irq_stat(cpu, ipi_irqs[i])); + + seq_printf(p, " %s\n", ipi_types[i]); + } +} + +u64 smp_irq_stat_cpu(unsigned int cpu) +{ + u64 sum = 0; + int i; + + for (i = 0; i < NR_IPI; i++) + sum += __get_irq_stat(cpu, ipi_irqs[i]); + +#ifdef CONFIG_LOCAL_TIMERS + sum += __get_irq_stat(cpu, local_timer_irqs); +#endif + + return sum; +} + +/* + * Timer (local or broadcast) support + */ +static DEFINE_PER_CPU(struct clock_event_device, percpu_clockevent); + +static void ipi_timer(void) +{ + struct clock_event_device *evt = &__get_cpu_var(percpu_clockevent); + evt->event_handler(evt); +} + +#ifdef CONFIG_LOCAL_TIMERS +asmlinkage void __exception_irq_entry do_local_timer(struct pt_regs *regs) +{ + struct pt_regs *old_regs = set_irq_regs(regs); + int cpu = smp_processor_id(); + + if (local_timer_ack()) { + __inc_irq_stat(cpu, local_timer_irqs); + irq_enter(); + ipi_timer(); + irq_exit(); + } + + set_irq_regs(old_regs); +} + +void show_local_irqs(struct seq_file *p, int prec) +{ + unsigned int cpu; + + seq_printf(p, "%*s: ", prec, "LOC"); + + for_each_present_cpu(cpu) + seq_printf(p, "%10u ", __get_irq_stat(cpu, local_timer_irqs)); + + seq_printf(p, " Local timer interrupts\n"); +} +#endif + +#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST +static void smp_timer_broadcast(const struct cpumask *mask) +{ + smp_cross_call(mask, IPI_TIMER); +} +#else +#define smp_timer_broadcast NULL +#endif + +static void broadcast_timer_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ +} + +static void __cpuinit broadcast_timer_setup(struct clock_event_device *evt) +{ + evt->name = "dummy_timer"; + evt->features = CLOCK_EVT_FEAT_ONESHOT | + CLOCK_EVT_FEAT_PERIODIC | + CLOCK_EVT_FEAT_DUMMY; + evt->rating = 400; + evt->mult = 1; + evt->set_mode = broadcast_timer_set_mode; + + clockevents_register_device(evt); +} + +void __cpuinit percpu_timer_setup(void) +{ + unsigned int cpu = smp_processor_id(); + struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu); + + evt->cpumask = cpumask_of(cpu); + evt->broadcast = smp_timer_broadcast; + + if (local_timer_setup(evt)) + broadcast_timer_setup(evt); +} + +#ifdef CONFIG_HOTPLUG_CPU +/* + * The generic clock events code purposely does not stop the local timer + * on CPU_DEAD/CPU_DEAD_FROZEN hotplug events, so we have to do it + * manually here. + */ +static void percpu_timer_stop(void) +{ + unsigned int cpu = smp_processor_id(); + struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu); + + evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt); +} +#endif + +static DEFINE_SPINLOCK(stop_lock); + +/* + * ipi_cpu_stop - handle IPI from smp_send_stop() + */ +static void ipi_cpu_stop(unsigned int cpu) +{ + if (system_state == SYSTEM_BOOTING || + system_state == SYSTEM_RUNNING) { + spin_lock(&stop_lock); + printk(KERN_CRIT "CPU%u: stopping\n", cpu); + dump_stack(); + spin_unlock(&stop_lock); + } + + set_cpu_online(cpu, false); + + local_fiq_disable(); + local_irq_disable(); + + while (1) + cpu_relax(); +} + +static cpumask_t backtrace_mask; +static DEFINE_RAW_SPINLOCK(backtrace_lock); + +/* "in progress" flag of arch_trigger_all_cpu_backtrace */ +static unsigned long backtrace_flag; + +void smp_send_all_cpu_backtrace(void) +{ + unsigned int this_cpu = smp_processor_id(); + int i; + + if (test_and_set_bit(0, &backtrace_flag)) + /* + * If there is already a trigger_all_cpu_backtrace() in progress + * (backtrace_flag == 1), don't output double cpu dump infos. + */ + return; + + cpumask_copy(&backtrace_mask, cpu_online_mask); + cpu_clear(this_cpu, backtrace_mask); + + pr_info("Backtrace for cpu %d (current):\n", this_cpu); + dump_stack(); + + pr_info("\nsending IPI to all other CPUs:\n"); + smp_cross_call(&backtrace_mask, IPI_CPU_BACKTRACE); + + /* Wait for up to 10 seconds for all other CPUs to do the backtrace */ + for (i = 0; i < 10 * 1000; i++) { + if (cpumask_empty(&backtrace_mask)) + break; + mdelay(1); + } + + clear_bit(0, &backtrace_flag); + smp_mb__after_clear_bit(); +} + +/* + * ipi_cpu_backtrace - handle IPI from smp_send_all_cpu_backtrace() + */ +static void ipi_cpu_backtrace(unsigned int cpu, struct pt_regs *regs) +{ + if (cpu_isset(cpu, backtrace_mask)) { + raw_spin_lock(&backtrace_lock); + pr_warning("IPI backtrace for cpu %d\n", cpu); + show_regs(regs); + raw_spin_unlock(&backtrace_lock); + cpu_clear(cpu, backtrace_mask); + } +} + +/* + * Main handler for inter-processor interrupts + */ +asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs) +{ + unsigned int cpu = smp_processor_id(); + struct pt_regs *old_regs = set_irq_regs(regs); + + if (ipinr >= IPI_TIMER && ipinr < IPI_TIMER + NR_IPI) + __inc_irq_stat(cpu, ipi_irqs[ipinr - IPI_TIMER]); + + switch (ipinr) { + case IPI_TIMER: + irq_enter(); + ipi_timer(); + irq_exit(); + break; + + case IPI_RESCHEDULE: + scheduler_ipi(); + break; + + case IPI_CALL_FUNC: + irq_enter(); + generic_smp_call_function_interrupt(); + irq_exit(); + break; + + case IPI_CALL_FUNC_SINGLE: + irq_enter(); + generic_smp_call_function_single_interrupt(); + irq_exit(); + break; + + case IPI_CPU_STOP: + irq_enter(); + ipi_cpu_stop(cpu); + irq_exit(); + break; + + case IPI_CPU_BACKTRACE: + ipi_cpu_backtrace(cpu, regs); + break; + + default: + printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n", + cpu, ipinr); + break; + } + set_irq_regs(old_regs); +} + +void smp_send_reschedule(int cpu) +{ + smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE); +} + +void smp_send_stop(void) +{ + unsigned long timeout; + + if (num_online_cpus() > 1) { + cpumask_t mask = cpu_online_map; + cpu_clear(smp_processor_id(), mask); + + smp_cross_call(&mask, IPI_CPU_STOP); + } + + /* Wait up to one second for other CPUs to stop */ + timeout = USEC_PER_SEC; + while (num_online_cpus() > 1 && timeout--) + udelay(1); + + if (num_online_cpus() > 1) + pr_warning("SMP: failed to stop secondary CPUs\n"); +} + +/* + * not supported here + */ +int setup_profiling_timer(unsigned int multiplier) +{ + return -EINVAL; +} |