/* ** 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, ...) do { } while(0) #endif /* DEBUG_SMP */ DEFINE_SPINLOCK(smp_lock); volatile struct task_struct *smp_init_current_idle_task; /* track which CPU is booting */ static volatile int cpu_now_booting __cpuinitdata; static int parisc_max_cpus __cpuinitdata = 1; DEFINE_PER_CPU(spinlock_t, ipi_lock) = SPIN_LOCK_UNLOCKED; enum ipi_message_type { IPI_NOP=0, IPI_RESCHEDULE=1, IPI_CALL_FUNC, IPI_CALL_FUNC_SINGLE, 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? */ set_cpu_online(smp_processor_id(), false); local_irq_disable(); for (;;) ; } irqreturn_t ipi_interrupt(int irq, void *dev_id) { int this_cpu = smp_processor_id(); struct cpuinfo_parisc *p = &per_cpu(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); generic_smp_call_function_interrupt(); break; case IPI_CALL_FUNC_SINGLE: smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC_SINGLE\n", this_cpu); generic_smp_call_function_single_interrupt(); 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 = &per_cpu(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, p->hpa); spin_unlock_irqrestore(lock, flags); } static void send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op) { int cpu; for_each_cpu(cpu, mask) ipi_send(cpu, op); } static inline void send_IPI_single(int dest_cpu, enum ipi_message_type op) { BUG_ON(dest_cpu == NO_PROC_ID); 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); } void arch_send_call_function_ipi_mask(const struct cpumask *mask) { send_IPI_mask(mask, IPI_CALL_FUNC); } void arch_send_call_function_single_ipi(int cpu) { send_IPI_single(cpu, IPI_CALL_FUNC_SINGLE); } /* * 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); } /* * 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_isset(cpunum, cpu_online_map)) { extern void machine_halt(void); /* arch/parisc.../process.c */ printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum); machine_halt(); } set_cpu_online(cpunum, true); /* Initialise the idle task for this CPU */ atomic_inc(&init_mm.mm_count); current->active_mm = &init_mm; BUG_ON(current->mm); 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; smp_cpu_init(slave_id); preempt_disable(); 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) { const struct cpuinfo_parisc *p = &per_cpu(cpu_data, 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(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->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, p->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 __init smp_prepare_boot_cpu(void) { int bootstrap_processor = per_cpu(cpu_data, 0).cpuid; /* Setup BSP mappings */ printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor); set_cpu_online(bootstrap_processor, true); set_cpu_present(bootstrap_processor, true); } /* ** 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) { init_cpu_present(cpumask_of(0)); 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