/* * SMP support for ppc. * * Written by Cort Dougan (cort@cs.nmt.edu) borrowing a great * deal of code from the sparc and intel versions. * * Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu> * * PowerPC-64 Support added by Dave Engebretsen, Peter Bergner, and * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #undef DEBUG #include <linux/config.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/sched.h> #include <linux/smp.h> #include <linux/interrupt.h> #include <linux/delay.h> #include <linux/init.h> #include <linux/spinlock.h> #include <linux/cache.h> #include <linux/err.h> #include <linux/sysdev.h> #include <linux/cpu.h> #include <linux/notifier.h> #include <linux/topology.h> #include <asm/ptrace.h> #include <asm/atomic.h> #include <asm/irq.h> #include <asm/page.h> #include <asm/pgtable.h> #include <asm/prom.h> #include <asm/smp.h> #include <asm/time.h> #include <asm/machdep.h> #include <asm/cputable.h> #include <asm/system.h> #include <asm/mpic.h> #include <asm/vdso_datapage.h> #ifdef CONFIG_PPC64 #include <asm/paca.h> #endif #ifdef DEBUG #include <asm/udbg.h> #define DBG(fmt...) udbg_printf(fmt) #else #define DBG(fmt...) #endif int smp_hw_index[NR_CPUS]; struct thread_info *secondary_ti; cpumask_t cpu_possible_map = CPU_MASK_NONE; cpumask_t cpu_online_map = CPU_MASK_NONE; cpumask_t cpu_sibling_map[NR_CPUS] = { [0 ... NR_CPUS-1] = CPU_MASK_NONE }; EXPORT_SYMBOL(cpu_online_map); EXPORT_SYMBOL(cpu_possible_map); /* SMP operations for this machine */ struct smp_ops_t *smp_ops; static volatile unsigned int cpu_callin_map[NR_CPUS]; void smp_call_function_interrupt(void); int smt_enabled_at_boot = 1; static void (*crash_ipi_function_ptr)(struct pt_regs *) = NULL; #ifdef CONFIG_MPIC int __init smp_mpic_probe(void) { int nr_cpus; DBG("smp_mpic_probe()...\n"); nr_cpus = cpus_weight(cpu_possible_map); DBG("nr_cpus: %d\n", nr_cpus); if (nr_cpus > 1) mpic_request_ipis(); return nr_cpus; } void __devinit smp_mpic_setup_cpu(int cpu) { mpic_setup_this_cpu(); } #endif /* CONFIG_MPIC */ #ifdef CONFIG_PPC64 void __devinit smp_generic_kick_cpu(int nr) { BUG_ON(nr < 0 || nr >= NR_CPUS); /* * The processor is currently spinning, waiting for the * cpu_start field to become non-zero After we set cpu_start, * the processor will continue on to secondary_start */ paca[nr].cpu_start = 1; smp_mb(); } #endif void smp_message_recv(int msg, struct pt_regs *regs) { switch(msg) { case PPC_MSG_CALL_FUNCTION: smp_call_function_interrupt(); break; case PPC_MSG_RESCHEDULE: /* XXX Do we have to do this? */ set_need_resched(); break; case PPC_MSG_DEBUGGER_BREAK: if (crash_ipi_function_ptr) { crash_ipi_function_ptr(regs); break; } #ifdef CONFIG_DEBUGGER debugger_ipi(regs); break; #endif /* CONFIG_DEBUGGER */ /* FALLTHROUGH */ default: printk("SMP %d: smp_message_recv(): unknown msg %d\n", smp_processor_id(), msg); break; } } void smp_send_reschedule(int cpu) { smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE); } #ifdef CONFIG_DEBUGGER void smp_send_debugger_break(int cpu) { smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK); } #endif #ifdef CONFIG_KEXEC void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *)) { crash_ipi_function_ptr = crash_ipi_callback; if (crash_ipi_callback) { mb(); smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_DEBUGGER_BREAK); } } #endif static void stop_this_cpu(void *dummy) { local_irq_disable(); while (1) ; } void smp_send_stop(void) { smp_call_function(stop_this_cpu, NULL, 1, 0); } /* * Structure and data for smp_call_function(). This is designed to minimise * static memory requirements. It also looks cleaner. * Stolen from the i386 version. */ static __cacheline_aligned_in_smp DEFINE_SPINLOCK(call_lock); static struct call_data_struct { void (*func) (void *info); void *info; atomic_t started; atomic_t finished; int wait; } *call_data; /* delay of at least 8 seconds */ #define SMP_CALL_TIMEOUT 8 /* * This function sends a 'generic call function' IPI to all other CPUs * in the system. * * [SUMMARY] Run a function on all other CPUs. * <func> The function to run. This must be fast and non-blocking. * <info> An arbitrary pointer to pass to the function. * <nonatomic> currently unused. * <wait> If true, wait (atomically) until function has completed on other CPUs. * [RETURNS] 0 on success, else a negative status code. Does not return until * remote CPUs are nearly ready to execute <<func>> or are or have executed. * * You must not call this function with disabled interrupts or from a * hardware interrupt handler or from a bottom half handler. */ int smp_call_function (void (*func) (void *info), void *info, int nonatomic, int wait) { struct call_data_struct data; int ret = -1, cpus; u64 timeout; /* Can deadlock when called with interrupts disabled */ WARN_ON(irqs_disabled()); data.func = func; data.info = info; atomic_set(&data.started, 0); data.wait = wait; if (wait) atomic_set(&data.finished, 0); spin_lock(&call_lock); /* Must grab online cpu count with preempt disabled, otherwise * it can change. */ cpus = num_online_cpus() - 1; if (!cpus) { ret = 0; goto out; } call_data = &data; smp_wmb(); /* Send a message to all other CPUs and wait for them to respond */ smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_CALL_FUNCTION); timeout = get_tb() + (u64) SMP_CALL_TIMEOUT * tb_ticks_per_sec; /* Wait for response */ while (atomic_read(&data.started) != cpus) { HMT_low(); if (get_tb() >= timeout) { printk("smp_call_function on cpu %d: other cpus not " "responding (%d)\n", smp_processor_id(), atomic_read(&data.started)); debugger(NULL); goto out; } } if (wait) { while (atomic_read(&data.finished) != cpus) { HMT_low(); if (get_tb() >= timeout) { printk("smp_call_function on cpu %d: other " "cpus not finishing (%d/%d)\n", smp_processor_id(), atomic_read(&data.finished), atomic_read(&data.started)); debugger(NULL); goto out; } } } ret = 0; out: call_data = NULL; HMT_medium(); spin_unlock(&call_lock); return ret; } EXPORT_SYMBOL(smp_call_function); void smp_call_function_interrupt(void) { void (*func) (void *info); void *info; int wait; /* call_data will be NULL if the sender timed out while * waiting on us to receive the call. */ if (!call_data) return; func = call_data->func; info = call_data->info; wait = call_data->wait; if (!wait) smp_mb__before_atomic_inc(); /* * Notify initiating CPU that I've grabbed the data and am * about to execute the function */ atomic_inc(&call_data->started); /* * At this point the info structure may be out of scope unless wait==1 */ (*func)(info); if (wait) { smp_mb__before_atomic_inc(); atomic_inc(&call_data->finished); } } extern struct gettimeofday_struct do_gtod; struct thread_info *current_set[NR_CPUS]; DECLARE_PER_CPU(unsigned int, pvr); static void __devinit smp_store_cpu_info(int id) { per_cpu(pvr, id) = mfspr(SPRN_PVR); } static void __init smp_create_idle(unsigned int cpu) { struct task_struct *p; /* create a process for the processor */ p = fork_idle(cpu); if (IS_ERR(p)) panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p)); #ifdef CONFIG_PPC64 paca[cpu].__current = p; #endif current_set[cpu] = p->thread_info; p->thread_info->cpu = cpu; } void __init smp_prepare_cpus(unsigned int max_cpus) { unsigned int cpu; DBG("smp_prepare_cpus\n"); /* * setup_cpu may need to be called on the boot cpu. We havent * spun any cpus up but lets be paranoid. */ BUG_ON(boot_cpuid != smp_processor_id()); /* Fixup boot cpu */ smp_store_cpu_info(boot_cpuid); cpu_callin_map[boot_cpuid] = 1; max_cpus = smp_ops->probe(); smp_space_timers(max_cpus); for_each_cpu(cpu) if (cpu != boot_cpuid) smp_create_idle(cpu); } void __devinit smp_prepare_boot_cpu(void) { BUG_ON(smp_processor_id() != boot_cpuid); cpu_set(boot_cpuid, cpu_online_map); #ifdef CONFIG_PPC64 paca[boot_cpuid].__current = current; #endif current_set[boot_cpuid] = current->thread_info; } #ifdef CONFIG_HOTPLUG_CPU /* State of each CPU during hotplug phases */ DEFINE_PER_CPU(int, cpu_state) = { 0 }; int generic_cpu_disable(void) { unsigned int cpu = smp_processor_id(); if (cpu == boot_cpuid) return -EBUSY; cpu_clear(cpu, cpu_online_map); #ifdef CONFIG_PPC64 vdso_data->processorCount--; fixup_irqs(cpu_online_map); #endif return 0; } int generic_cpu_enable(unsigned int cpu) { /* Do the normal bootup if we haven't * already bootstrapped. */ if (system_state != SYSTEM_RUNNING) return -ENOSYS; /* get the target out of it's holding state */ per_cpu(cpu_state, cpu) = CPU_UP_PREPARE; smp_wmb(); while (!cpu_online(cpu)) cpu_relax(); #ifdef CONFIG_PPC64 fixup_irqs(cpu_online_map); /* counter the irq disable in fixup_irqs */ local_irq_enable(); #endif return 0; } void generic_cpu_die(unsigned int cpu) { int i; for (i = 0; i < 100; i++) { smp_rmb(); if (per_cpu(cpu_state, cpu) == CPU_DEAD) return; msleep(100); } printk(KERN_ERR "CPU%d didn't die...\n", cpu); } void generic_mach_cpu_die(void) { unsigned int cpu; local_irq_disable(); cpu = smp_processor_id(); printk(KERN_DEBUG "CPU%d offline\n", cpu); __get_cpu_var(cpu_state) = CPU_DEAD; smp_wmb(); while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE) cpu_relax(); #ifdef CONFIG_PPC64 flush_tlb_pending(); #endif cpu_set(cpu, cpu_online_map); local_irq_enable(); } #endif static int __devinit cpu_enable(unsigned int cpu) { if (smp_ops->cpu_enable) return smp_ops->cpu_enable(cpu); return -ENOSYS; } int __devinit __cpu_up(unsigned int cpu) { int c; secondary_ti = current_set[cpu]; if (!cpu_enable(cpu)) return 0; if (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)) return -EINVAL; /* Make sure callin-map entry is 0 (can be leftover a CPU * hotplug */ cpu_callin_map[cpu] = 0; /* The information for processor bringup must * be written out to main store before we release * the processor. */ smp_mb(); /* wake up cpus */ DBG("smp: kicking cpu %d\n", cpu); smp_ops->kick_cpu(cpu); /* * wait to see if the cpu made a callin (is actually up). * use this value that I found through experimentation. * -- Cort */ if (system_state < SYSTEM_RUNNING) for (c = 5000; c && !cpu_callin_map[cpu]; c--) udelay(100); #ifdef CONFIG_HOTPLUG_CPU else /* * CPUs can take much longer to come up in the * hotplug case. Wait five seconds. */ for (c = 25; c && !cpu_callin_map[cpu]; c--) { msleep(200); } #endif if (!cpu_callin_map[cpu]) { printk("Processor %u is stuck.\n", cpu); return -ENOENT; } printk("Processor %u found.\n", cpu); if (smp_ops->give_timebase) smp_ops->give_timebase(); /* Wait until cpu puts itself in the online map */ while (!cpu_online(cpu)) cpu_relax(); return 0; } /* Activate a secondary processor. */ int __devinit start_secondary(void *unused) { unsigned int cpu = smp_processor_id(); atomic_inc(&init_mm.mm_count); current->active_mm = &init_mm; smp_store_cpu_info(cpu); set_dec(tb_ticks_per_jiffy); preempt_disable(); cpu_callin_map[cpu] = 1; smp_ops->setup_cpu(cpu); if (smp_ops->take_timebase) smp_ops->take_timebase(); spin_lock(&call_lock); cpu_set(cpu, cpu_online_map); spin_unlock(&call_lock); local_irq_enable(); cpu_idle(); return 0; } int setup_profiling_timer(unsigned int multiplier) { return 0; } void __init smp_cpus_done(unsigned int max_cpus) { cpumask_t old_mask; /* We want the setup_cpu() here to be called from CPU 0, but our * init thread may have been "borrowed" by another CPU in the meantime * se we pin us down to CPU 0 for a short while */ old_mask = current->cpus_allowed; set_cpus_allowed(current, cpumask_of_cpu(boot_cpuid)); smp_ops->setup_cpu(boot_cpuid); set_cpus_allowed(current, old_mask); dump_numa_cpu_topology(); } #ifdef CONFIG_HOTPLUG_CPU int __cpu_disable(void) { if (smp_ops->cpu_disable) return smp_ops->cpu_disable(); return -ENOSYS; } void __cpu_die(unsigned int cpu) { if (smp_ops->cpu_die) smp_ops->cpu_die(cpu); } #endif