/* * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * 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, }; static inline void identity_mapping_add(pgd_t *pgd, unsigned long start, unsigned long end) { unsigned long addr, prot; pmd_t *pmd; prot = PMD_TYPE_SECT | PMD_SECT_AP_WRITE; if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale()) prot |= PMD_BIT4; for (addr = start & PGDIR_MASK; addr < end;) { pmd = pmd_offset(pgd + pgd_index(addr), addr); pmd[0] = __pmd(addr | prot); addr += SECTION_SIZE; pmd[1] = __pmd(addr | prot); addr += SECTION_SIZE; flush_pmd_entry(pmd); outer_clean_range(__pa(pmd), __pa(pmd + 1)); } } static inline void identity_mapping_del(pgd_t *pgd, unsigned long start, unsigned long end) { unsigned long addr; pmd_t *pmd; for (addr = start & PGDIR_MASK; addr < end; addr += PGDIR_SIZE) { pmd = pmd_offset(pgd + pgd_index(addr), addr); pmd[0] = __pmd(0); pmd[1] = __pmd(0); clean_pmd_entry(pmd); outer_clean_range(__pa(pmd), __pa(pmd + 1)); } } 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); __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) { unsigned long timeout; /* * CPU was successfully started, wait for it * to come online or time out. */ timeout = jiffies + HZ; while (time_before(jiffies, timeout)) { if (cpu_online(cpu)) break; udelay(10); barrier(); } 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(); printk("CPU%u: Booted secondary processor\n", cpu); /* * All kernel threads share the same mm context; grab a * reference and switch to it. */ atomic_inc(&mm->mm_users); 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(); cpu_init(); preempt_disable(); trace_hardirqs_off(); /* * Give the platform a chance to do its own initialisation. */ platform_secondary_init(cpu); /* * Enable local interrupts. */ notify_cpu_starting(cpu); local_irq_enable(); local_fiq_enable(); /* * Setup the percpu timer for this CPU. */ percpu_timer_setup(); calibrate_delay(); smp_store_cpu_info(cpu); /* * OK, now it's safe to let the boot CPU continue */ set_cpu_online(cpu, true); /* * 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); } } 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"), }; 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); irq_enter(); evt->event_handler(evt); irq_exit(); } #ifdef CONFIG_LOCAL_TIMERS asmlinkage void __exception 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); ipi_timer(); } 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 #ifndef CONFIG_LOCAL_TIMERS static void broadcast_timer_set_mode(enum clock_event_mode mode, struct clock_event_device *evt) { } static void local_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); } #endif 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; local_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(); } /* * Main handler for inter-processor interrupts */ asmlinkage void __exception 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: ipi_timer(); break; case IPI_RESCHEDULE: /* * nothing more to do - eveything is * done on the interrupt return path */ break; case IPI_CALL_FUNC: generic_smp_call_function_interrupt(); break; case IPI_CALL_FUNC_SINGLE: generic_smp_call_function_single_interrupt(); break; case IPI_CPU_STOP: ipi_cpu_stop(cpu); 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; }