/* ** SMP Support ** ** Copyright (C) 1999 Walt Drummond ** Copyright (C) 1999 David Mosberger-Tang ** Copyright (C) 2001,2004 Grant Grundler ** ** Lots of stuff stolen from arch/alpha/kernel/smp.c ** ...and then parisc stole from arch/ia64/kernel/smp.c. Thanks David! :^) ** ** Thanks to John Curry and Ullas Ponnadi. I learned a lot from their work. ** -grant (1/12/2001) ** ** 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. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* for CPU_IRQ_REGION and friends */ #include #include #include #include #include #include #include #include #undef DEBUG_SMP #ifdef DEBUG_SMP static int smp_debug_lvl = 0; #define smp_debug(lvl, printargs...) \ if (lvl >= smp_debug_lvl) \ printk(printargs); #else #define smp_debug(lvl, ...) #endif /* DEBUG_SMP */ DEFINE_SPINLOCK(smp_lock); volatile struct task_struct *smp_init_current_idle_task; static volatile int cpu_now_booting __read_mostly = 0; /* track which CPU is booting */ static int parisc_max_cpus __read_mostly = 1; /* online cpus are ones that we've managed to bring up completely * possible cpus are all valid cpu * present cpus are all detected cpu * * On startup we bring up the "possible" cpus. Since we discover * CPUs later, we add them as hotplug, so the possible cpu mask is * empty in the beginning. */ cpumask_t cpu_online_map __read_mostly = CPU_MASK_NONE; /* Bitmap of online CPUs */ cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL; /* Bitmap of Present CPUs */ EXPORT_SYMBOL(cpu_online_map); EXPORT_SYMBOL(cpu_possible_map); DEFINE_PER_CPU(spinlock_t, ipi_lock) = SPIN_LOCK_UNLOCKED; struct smp_call_struct { void (*func) (void *info); void *info; long wait; atomic_t unstarted_count; atomic_t unfinished_count; }; static volatile struct smp_call_struct *smp_call_function_data; enum ipi_message_type { IPI_NOP=0, IPI_RESCHEDULE=1, IPI_CALL_FUNC, IPI_CPU_START, IPI_CPU_STOP, IPI_CPU_TEST }; /********** SMP inter processor interrupt and communication routines */ #undef PER_CPU_IRQ_REGION #ifdef PER_CPU_IRQ_REGION /* XXX REVISIT Ignore for now. ** *May* need this "hook" to register IPI handler ** once we have perCPU ExtIntr switch tables. */ static void ipi_init(int cpuid) { #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region if(cpu_online(cpuid) ) { switch_to_idle_task(current); } return; } #endif /* ** Yoink this CPU from the runnable list... ** */ static void halt_processor(void) { /* REVISIT : redirect I/O Interrupts to another CPU? */ /* REVISIT : does PM *know* this CPU isn't available? */ cpu_clear(smp_processor_id(), cpu_online_map); local_irq_disable(); for (;;) ; } irqreturn_t ipi_interrupt(int irq, void *dev_id) { int this_cpu = smp_processor_id(); struct cpuinfo_parisc *p = &cpu_data[this_cpu]; unsigned long ops; unsigned long flags; /* Count this now; we may make a call that never returns. */ p->ipi_count++; mb(); /* Order interrupt and bit testing. */ for (;;) { spinlock_t *lock = &per_cpu(ipi_lock, this_cpu); spin_lock_irqsave(lock, flags); ops = p->pending_ipi; p->pending_ipi = 0; spin_unlock_irqrestore(lock, flags); mb(); /* Order bit clearing and data access. */ if (!ops) break; while (ops) { unsigned long which = ffz(~ops); ops &= ~(1 << which); switch (which) { case IPI_NOP: smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu); break; case IPI_RESCHEDULE: smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu); /* * Reschedule callback. Everything to be * done is done by the interrupt return path. */ break; case IPI_CALL_FUNC: smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu); { volatile struct smp_call_struct *data; void (*func)(void *info); void *info; int wait; data = smp_call_function_data; func = data->func; info = data->info; wait = data->wait; mb(); atomic_dec ((atomic_t *)&data->unstarted_count); /* At this point, *data can't * be relied upon. */ (*func)(info); /* Notify the sending CPU that the * task is done. */ mb(); if (wait) atomic_dec ((atomic_t *)&data->unfinished_count); } break; case IPI_CPU_START: smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu); break; case IPI_CPU_STOP: smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu); halt_processor(); break; case IPI_CPU_TEST: smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu); break; default: printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n", this_cpu, which); return IRQ_NONE; } /* Switch */ /* let in any pending interrupts */ local_irq_enable(); local_irq_disable(); } /* while (ops) */ } return IRQ_HANDLED; } static inline void ipi_send(int cpu, enum ipi_message_type op) { struct cpuinfo_parisc *p = &cpu_data[cpu]; spinlock_t *lock = &per_cpu(ipi_lock, cpu); unsigned long flags; spin_lock_irqsave(lock, flags); p->pending_ipi |= 1 << op; gsc_writel(IPI_IRQ - CPU_IRQ_BASE, cpu_data[cpu].hpa); spin_unlock_irqrestore(lock, flags); } static inline void send_IPI_single(int dest_cpu, enum ipi_message_type op) { if (dest_cpu == NO_PROC_ID) { BUG(); return; } ipi_send(dest_cpu, op); } static inline void send_IPI_allbutself(enum ipi_message_type op) { int i; for_each_online_cpu(i) { if (i != smp_processor_id()) send_IPI_single(i, op); } } inline void smp_send_stop(void) { send_IPI_allbutself(IPI_CPU_STOP); } static inline void smp_send_start(void) { send_IPI_allbutself(IPI_CPU_START); } void smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); } void smp_send_all_nop(void) { send_IPI_allbutself(IPI_NOP); } /** * Run a function on all other CPUs. * The function to run. This must be fast and non-blocking. * An arbitrary pointer to pass to the function. * If true, keep retrying until ready. * If true, wait 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 * or have executed. */ int smp_call_function (void (*func) (void *info), void *info, int retry, int wait) { struct smp_call_struct data; unsigned long timeout; static DEFINE_SPINLOCK(lock); int retries = 0; if (num_online_cpus() < 2) return 0; /* Can deadlock when called with interrupts disabled */ WARN_ON(irqs_disabled()); /* can also deadlock if IPIs are disabled */ WARN_ON((get_eiem() & (1UL<<(CPU_IRQ_MAX - IPI_IRQ))) == 0); data.func = func; data.info = info; data.wait = wait; atomic_set(&data.unstarted_count, num_online_cpus() - 1); atomic_set(&data.unfinished_count, num_online_cpus() - 1); if (retry) { spin_lock (&lock); while (smp_call_function_data != 0) barrier(); } else { spin_lock (&lock); if (smp_call_function_data) { spin_unlock (&lock); return -EBUSY; } } smp_call_function_data = &data; spin_unlock (&lock); /* Send a message to all other CPUs and wait for them to respond */ send_IPI_allbutself(IPI_CALL_FUNC); retry: /* Wait for response */ timeout = jiffies + HZ; while ( (atomic_read (&data.unstarted_count) > 0) && time_before (jiffies, timeout) ) barrier (); if (atomic_read (&data.unstarted_count) > 0) { printk(KERN_CRIT "SMP CALL FUNCTION TIMED OUT! (cpu=%d), try %d\n", smp_processor_id(), ++retries); goto retry; } /* We either got one or timed out. Release the lock */ mb(); smp_call_function_data = NULL; while (wait && atomic_read (&data.unfinished_count) > 0) barrier (); return 0; } EXPORT_SYMBOL(smp_call_function); /* * Flush all other CPU's tlb and then mine. Do this with on_each_cpu() * as we want to ensure all TLB's flushed before proceeding. */ void smp_flush_tlb_all(void) { on_each_cpu(flush_tlb_all_local, NULL, 1, 1); } /* * Called by secondaries to update state and initialize CPU registers. */ static void __init smp_cpu_init(int cpunum) { extern int init_per_cpu(int); /* arch/parisc/kernel/processor.c */ extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */ extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */ /* Set modes and Enable floating point coprocessor */ (void) init_per_cpu(cpunum); disable_sr_hashing(); mb(); /* Well, support 2.4 linux scheme as well. */ if (cpu_test_and_set(cpunum, cpu_online_map)) { extern void machine_halt(void); /* arch/parisc.../process.c */ printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum); machine_halt(); } /* Initialise the idle task for this CPU */ atomic_inc(&init_mm.mm_count); current->active_mm = &init_mm; if(current->mm) BUG(); enter_lazy_tlb(&init_mm, current); init_IRQ(); /* make sure no IRQs are enabled or pending */ start_cpu_itimer(); } /* * Slaves start using C here. Indirectly called from smp_slave_stext. * Do what start_kernel() and main() do for boot strap processor (aka monarch) */ void __init smp_callin(void) { int slave_id = cpu_now_booting; #if 0 void *istack; #endif smp_cpu_init(slave_id); preempt_disable(); #if 0 /* NOT WORKING YET - see entry.S */ istack = (void *)__get_free_pages(GFP_KERNEL,ISTACK_ORDER); if (istack == NULL) { printk(KERN_CRIT "Failed to allocate interrupt stack for cpu %d\n",slave_id); BUG(); } mtctl(istack,31); #endif flush_cache_all_local(); /* start with known state */ flush_tlb_all_local(NULL); local_irq_enable(); /* Interrupts have been off until now */ cpu_idle(); /* Wait for timer to schedule some work */ /* NOTREACHED */ panic("smp_callin() AAAAaaaaahhhh....\n"); } /* * Bring one cpu online. */ int __cpuinit smp_boot_one_cpu(int cpuid) { struct task_struct *idle; long timeout; /* * Create an idle task for this CPU. Note the address wed* give * to kernel_thread is irrelevant -- it's going to start * where OS_BOOT_RENDEVZ vector in SAL says to start. But * this gets all the other task-y sort of data structures set * up like we wish. We need to pull the just created idle task * off the run queue and stuff it into the init_tasks[] array. * Sheesh . . . */ idle = fork_idle(cpuid); if (IS_ERR(idle)) panic("SMP: fork failed for CPU:%d", cpuid); task_thread_info(idle)->cpu = cpuid; /* Let _start know what logical CPU we're booting ** (offset into init_tasks[],cpu_data[]) */ cpu_now_booting = cpuid; /* ** boot strap code needs to know the task address since ** it also contains the process stack. */ smp_init_current_idle_task = idle ; mb(); printk("Releasing cpu %d now, hpa=%lx\n", cpuid, cpu_data[cpuid].hpa); /* ** This gets PDC to release the CPU from a very tight loop. ** ** From the PA-RISC 2.0 Firmware Architecture Reference Specification: ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which ** is executed after receiving the rendezvous signal (an interrupt to ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the ** contents of memory are valid." */ gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, cpu_data[cpuid].hpa); mb(); /* * OK, wait a bit for that CPU to finish staggering about. * Slave will set a bit when it reaches smp_cpu_init(). * Once the "monarch CPU" sees the bit change, it can move on. */ for (timeout = 0; timeout < 10000; timeout++) { if(cpu_online(cpuid)) { /* Which implies Slave has started up */ cpu_now_booting = 0; smp_init_current_idle_task = NULL; goto alive ; } udelay(100); barrier(); } put_task_struct(idle); idle = NULL; printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid); return -1; alive: /* Remember the Slave data */ smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n", cpuid, timeout * 100); return 0; } void __devinit smp_prepare_boot_cpu(void) { int bootstrap_processor=cpu_data[0].cpuid; /* CPU ID of BSP */ /* Setup BSP mappings */ printk("SMP: bootstrap CPU ID is %d\n",bootstrap_processor); cpu_set(bootstrap_processor, cpu_online_map); cpu_set(bootstrap_processor, cpu_present_map); } /* ** inventory.c:do_inventory() hasn't yet been run and thus we ** don't 'discover' the additional CPUs until later. */ void __init smp_prepare_cpus(unsigned int max_cpus) { cpus_clear(cpu_present_map); cpu_set(0, cpu_present_map); parisc_max_cpus = max_cpus; if (!max_cpus) printk(KERN_INFO "SMP mode deactivated.\n"); } void smp_cpus_done(unsigned int cpu_max) { return; } int __cpuinit __cpu_up(unsigned int cpu) { if (cpu != 0 && cpu < parisc_max_cpus) smp_boot_one_cpu(cpu); return cpu_online(cpu) ? 0 : -ENOSYS; } #ifdef CONFIG_PROC_FS int __init setup_profiling_timer(unsigned int multiplier) { return -EINVAL; } #endif