/* * 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/mm.h> #include <linux/err.h> #include <linux/cpu.h> #include <linux/smp.h> #include <linux/seq_file.h> #include <linux/irq.h> #include <asm/atomic.h> #include <asm/cacheflush.h> #include <asm/cpu.h> #include <asm/mmu_context.h> #include <asm/pgtable.h> #include <asm/pgalloc.h> #include <asm/processor.h> #include <asm/tlbflush.h> #include <asm/ptrace.h> /* * bitmask of present and online CPUs. * The present bitmask indicates that the CPU is physically present. * The online bitmask indicates that the CPU is up and running. */ cpumask_t cpu_possible_map; EXPORT_SYMBOL(cpu_possible_map); cpumask_t cpu_online_map; EXPORT_SYMBOL(cpu_online_map); /* * 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; /* * structures for inter-processor calls * - A collection of single bit ipi messages. */ struct ipi_data { spinlock_t lock; unsigned long ipi_count; unsigned long bits; }; static DEFINE_PER_CPU(struct ipi_data, ipi_data) = { .lock = SPIN_LOCK_UNLOCKED, }; enum ipi_msg_type { IPI_TIMER, IPI_RESCHEDULE, IPI_CALL_FUNC, IPI_CPU_STOP, }; struct smp_call_struct { void (*func)(void *info); void *info; int wait; cpumask_t pending; cpumask_t unfinished; }; static struct smp_call_struct * volatile smp_call_function_data; static DEFINE_SPINLOCK(smp_call_function_lock); 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; pmd_t *pmd; 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; } /* * 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); pmd = pmd_offset(pgd, PHYS_OFFSET); *pmd = __pmd((PHYS_OFFSET & PGDIR_MASK) | PMD_TYPE_SECT | PMD_SECT_AP_WRITE); /* * 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); wmb(); /* * 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)) ret = -EIO; } secondary_data.stack = NULL; secondary_data.pgdir = 0; *pmd_offset(pgd, PHYS_OFFSET) = __pmd(0); pgd_free(pgd); if (ret) { printk(KERN_CRIT "CPU%u: processor failed to boot\n", cpu); /* * FIXME: We need to clean up the new idle thread. --rmk */ } return ret; } #ifdef CONFIG_HOTPLUG_CPU /* * __cpu_disable runs on the processor to be shutdown. */ int __cpuexit __cpu_disable(void) { unsigned int cpu = smp_processor_id(); struct task_struct *p; int ret; ret = mach_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. */ cpu_clear(cpu, cpu_online_map); /* * OK - migrate IRQs away from this CPU */ migrate_irqs(); /* * Stop the local timer for this CPU. */ local_timer_stop(cpu); /* * 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) cpu_clear(cpu, p->mm->cpu_vm_mask); } read_unlock(&tasklist_lock); 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 __cpuexit __cpu_die(unsigned int 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 __cpuexit cpu_die(void) { unsigned int cpu = smp_processor_id(); local_irq_disable(); idle_task_exit(); /* * 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" " b secondary_start_kernel" : : "r" (task_stack_page(current) + THREAD_SIZE - 8)); } #endif /* CONFIG_HOTPLUG_CPU */ /* * 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; cpu_set(cpu, mm->cpu_vm_mask); cpu_switch_mm(mm->pgd, mm); enter_lazy_tlb(mm, current); local_flush_tlb_all(); cpu_init(); preempt_disable(); /* * Give the platform a chance to do its own initialisation. */ platform_secondary_init(cpu); /* * Enable local interrupts. */ local_irq_enable(); local_fiq_enable(); calibrate_delay(); smp_store_cpu_info(cpu); /* * OK, now it's safe to let the boot CPU continue */ cpu_set(cpu, cpu_online_map); /* * Setup local timer for this CPU. */ local_timer_setup(cpu); /* * OK, it's off to the idle thread for us */ cpu_idle(); } /* * Called by both boot and secondaries to move global data into * per-processor storage. */ 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; } 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; } static void send_ipi_message(cpumask_t callmap, enum ipi_msg_type msg) { unsigned long flags; unsigned int cpu; local_irq_save(flags); for_each_cpu_mask(cpu, callmap) { struct ipi_data *ipi = &per_cpu(ipi_data, cpu); spin_lock(&ipi->lock); ipi->bits |= 1 << msg; spin_unlock(&ipi->lock); } /* * Call the platform specific cross-CPU call function. */ smp_cross_call(callmap); local_irq_restore(flags); } /* * You must not call this function with disabled interrupts, from a * hardware interrupt handler, nor from a bottom half handler. */ static int smp_call_function_on_cpu(void (*func)(void *info), void *info, int retry, int wait, cpumask_t callmap) { struct smp_call_struct data; unsigned long timeout; int ret = 0; data.func = func; data.info = info; data.wait = wait; cpu_clear(smp_processor_id(), callmap); if (cpus_empty(callmap)) goto out; data.pending = callmap; if (wait) data.unfinished = callmap; /* * try to get the mutex on smp_call_function_data */ spin_lock(&smp_call_function_lock); smp_call_function_data = &data; send_ipi_message(callmap, IPI_CALL_FUNC); timeout = jiffies + HZ; while (!cpus_empty(data.pending) && time_before(jiffies, timeout)) barrier(); /* * did we time out? */ if (!cpus_empty(data.pending)) { /* * this may be causing our panic - report it */ printk(KERN_CRIT "CPU%u: smp_call_function timeout for %p(%p)\n" " callmap %lx pending %lx, %swait\n", smp_processor_id(), func, info, *cpus_addr(callmap), *cpus_addr(data.pending), wait ? "" : "no "); /* * TRACE */ timeout = jiffies + (5 * HZ); while (!cpus_empty(data.pending) && time_before(jiffies, timeout)) barrier(); if (cpus_empty(data.pending)) printk(KERN_CRIT " RESOLVED\n"); else printk(KERN_CRIT " STILL STUCK\n"); } /* * whatever happened, we're done with the data, so release it */ smp_call_function_data = NULL; spin_unlock(&smp_call_function_lock); if (!cpus_empty(data.pending)) { ret = -ETIMEDOUT; goto out; } if (wait) while (!cpus_empty(data.unfinished)) barrier(); out: return 0; } int smp_call_function(void (*func)(void *info), void *info, int retry, int wait) { return smp_call_function_on_cpu(func, info, retry, wait, cpu_online_map); } EXPORT_SYMBOL_GPL(smp_call_function); void show_ipi_list(struct seq_file *p) { unsigned int cpu; seq_puts(p, "IPI:"); for_each_present_cpu(cpu) seq_printf(p, " %10lu", per_cpu(ipi_data, cpu).ipi_count); seq_putc(p, '\n'); } void show_local_irqs(struct seq_file *p) { unsigned int cpu; seq_printf(p, "LOC: "); for_each_present_cpu(cpu) seq_printf(p, "%10u ", irq_stat[cpu].local_timer_irqs); seq_putc(p, '\n'); } static void ipi_timer(void) { irq_enter(); profile_tick(CPU_PROFILING); update_process_times(user_mode(get_irq_regs())); 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()) { irq_stat[cpu].local_timer_irqs++; ipi_timer(); } set_irq_regs(old_regs); } #endif /* * ipi_call_function - handle IPI from smp_call_function() * * Note that we copy data out of the cross-call structure and then * let the caller know that we're here and have done with their data */ static void ipi_call_function(unsigned int cpu) { struct smp_call_struct *data = smp_call_function_data; void (*func)(void *info) = data->func; void *info = data->info; int wait = data->wait; cpu_clear(cpu, data->pending); func(info); if (wait) cpu_clear(cpu, data->unfinished); } static DEFINE_SPINLOCK(stop_lock); /* * ipi_cpu_stop - handle IPI from smp_send_stop() */ static void ipi_cpu_stop(unsigned int cpu) { spin_lock(&stop_lock); printk(KERN_CRIT "CPU%u: stopping\n", cpu); dump_stack(); spin_unlock(&stop_lock); cpu_clear(cpu, cpu_online_map); local_fiq_disable(); local_irq_disable(); while (1) cpu_relax(); } /* * Main handler for inter-processor interrupts * * For ARM, the ipimask now only identifies a single * category of IPI (Bit 1 IPIs have been replaced by a * different mechanism): * * Bit 0 - Inter-processor function call */ asmlinkage void __exception do_IPI(struct pt_regs *regs) { unsigned int cpu = smp_processor_id(); struct ipi_data *ipi = &per_cpu(ipi_data, cpu); struct pt_regs *old_regs = set_irq_regs(regs); ipi->ipi_count++; for (;;) { unsigned long msgs; spin_lock(&ipi->lock); msgs = ipi->bits; ipi->bits = 0; spin_unlock(&ipi->lock); if (!msgs) break; do { unsigned nextmsg; nextmsg = msgs & -msgs; msgs &= ~nextmsg; nextmsg = ffz(~nextmsg); switch (nextmsg) { 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: ipi_call_function(cpu); break; case IPI_CPU_STOP: ipi_cpu_stop(cpu); break; default: printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n", cpu, nextmsg); break; } } while (msgs); } set_irq_regs(old_regs); } void smp_send_reschedule(int cpu) { send_ipi_message(cpumask_of_cpu(cpu), IPI_RESCHEDULE); } void smp_send_timer(void) { cpumask_t mask = cpu_online_map; cpu_clear(smp_processor_id(), mask); send_ipi_message(mask, IPI_TIMER); } void smp_send_stop(void) { cpumask_t mask = cpu_online_map; cpu_clear(smp_processor_id(), mask); send_ipi_message(mask, IPI_CPU_STOP); } /* * not supported here */ int setup_profiling_timer(unsigned int multiplier) { return -EINVAL; } static int on_each_cpu_mask(void (*func)(void *), void *info, int retry, int wait, cpumask_t mask) { int ret = 0; preempt_disable(); ret = smp_call_function_on_cpu(func, info, retry, wait, mask); if (cpu_isset(smp_processor_id(), mask)) func(info); preempt_enable(); return ret; } /**********************************************************************/ /* * TLB operations */ struct tlb_args { struct vm_area_struct *ta_vma; unsigned long ta_start; unsigned long ta_end; }; static inline void ipi_flush_tlb_all(void *ignored) { local_flush_tlb_all(); } static inline void ipi_flush_tlb_mm(void *arg) { struct mm_struct *mm = (struct mm_struct *)arg; local_flush_tlb_mm(mm); } static inline void ipi_flush_tlb_page(void *arg) { struct tlb_args *ta = (struct tlb_args *)arg; local_flush_tlb_page(ta->ta_vma, ta->ta_start); } static inline void ipi_flush_tlb_kernel_page(void *arg) { struct tlb_args *ta = (struct tlb_args *)arg; local_flush_tlb_kernel_page(ta->ta_start); } static inline void ipi_flush_tlb_range(void *arg) { struct tlb_args *ta = (struct tlb_args *)arg; local_flush_tlb_range(ta->ta_vma, ta->ta_start, ta->ta_end); } static inline void ipi_flush_tlb_kernel_range(void *arg) { struct tlb_args *ta = (struct tlb_args *)arg; local_flush_tlb_kernel_range(ta->ta_start, ta->ta_end); } void flush_tlb_all(void) { on_each_cpu(ipi_flush_tlb_all, NULL, 1, 1); } void flush_tlb_mm(struct mm_struct *mm) { cpumask_t mask = mm->cpu_vm_mask; on_each_cpu_mask(ipi_flush_tlb_mm, mm, 1, 1, mask); } void flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr) { cpumask_t mask = vma->vm_mm->cpu_vm_mask; struct tlb_args ta; ta.ta_vma = vma; ta.ta_start = uaddr; on_each_cpu_mask(ipi_flush_tlb_page, &ta, 1, 1, mask); } void flush_tlb_kernel_page(unsigned long kaddr) { struct tlb_args ta; ta.ta_start = kaddr; on_each_cpu(ipi_flush_tlb_kernel_page, &ta, 1, 1); } void flush_tlb_range(struct vm_area_struct *vma, unsigned long start, unsigned long end) { cpumask_t mask = vma->vm_mm->cpu_vm_mask; struct tlb_args ta; ta.ta_vma = vma; ta.ta_start = start; ta.ta_end = end; on_each_cpu_mask(ipi_flush_tlb_range, &ta, 1, 1, mask); } void flush_tlb_kernel_range(unsigned long start, unsigned long end) { struct tlb_args ta; ta.ta_start = start; ta.ta_end = end; on_each_cpu(ipi_flush_tlb_kernel_range, &ta, 1, 1); }