/* ** SMP Support ** ** Copyright (C) 1999 Walt Drummond ** Copyright (C) 1999 David Mosberger-Tang ** Copyright (C) 2001 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 alot 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. */ #define __KERNEL_SYSCALLS__ #undef ENTRY_SYS_CPUS /* syscall support for iCOD-like functionality */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* for flush_tlb_all() proto/macro */ #include #include /* for CPU_IRQ_REGION and friends */ #include #include #include #include #include #include #include #define kDEBUG 0 spinlock_t pa_dbit_lock = SPIN_LOCK_UNLOCKED; spinlock_t smp_lock = SPIN_LOCK_UNLOCKED; volatile struct task_struct *smp_init_current_idle_task; spinlock_t kernel_flag = SPIN_LOCK_UNLOCKED; static volatile int smp_commenced = 0; /* Set when the idlers are all forked */ static volatile int cpu_now_booting = 0; /* track which CPU is booting */ volatile unsigned long cpu_online_map = 0; /* Bitmap of online CPUs */ #define IS_LOGGED_IN(cpunum) (test_bit(cpunum, (atomic_t *)&cpu_online_map)) int smp_num_cpus = 1; int smp_threads_ready = 0; static int max_cpus = -1; /* Command line */ 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) { /* If CPU is present ... */ #ifdef ENTRY_SYS_CPUS /* *and* running (not stopped) ... */ #error iCOD support wants state checked here. #endif #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region if(IS_LOGGED_IN(cpuid) ) { switch_to_idle_task(current); } return; } #endif /* ** Yoink this CPU from the runnable list... ** */ static void halt_processor(void) { #ifdef ENTRY_SYS_CPUS #error halt_processor() needs rework /* ** o migrate I/O interrupts off this CPU. ** o leave IPI enabled - __cli() will disable IPI. ** o leave CPU in online map - just change the state */ cpu_data[this_cpu].state = STATE_STOPPED; mark_bh(IPI_BH); #else /* REVISIT : redirect I/O Interrupts to another CPU? */ /* REVISIT : does PM *know* this CPU isn't available? */ clear_bit(smp_processor_id(), (void *)&cpu_online_map); __cli(); for (;;) ; #endif } void ipi_interrupt(int irq, void *dev_id, struct pt_regs *regs) { 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 (;;) { spin_lock_irqsave(&(p->lock),flags); ops = p->pending_ipi; p->pending_ipi = 0; spin_unlock_irqrestore(&(p->lock),flags); mb(); /* Order bit clearing and data access. */ if (!ops) break; while (ops) { unsigned long which = ffz(~ops); switch (which) { case IPI_RESCHEDULE: #if (kDEBUG>=100) printk(KERN_DEBUG "CPU%d IPI_RESCHEDULE\n",this_cpu); #endif /* kDEBUG */ ops &= ~(1 << IPI_RESCHEDULE); /* * Reschedule callback. Everything to be * done is done by the interrupt return path. */ break; case IPI_CALL_FUNC: #if (kDEBUG>=100) printk(KERN_DEBUG "CPU%d IPI_CALL_FUNC\n",this_cpu); #endif /* kDEBUG */ ops &= ~(1 << IPI_CALL_FUNC); { 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: #if (kDEBUG>=100) printk(KERN_DEBUG "CPU%d IPI_CPU_START\n",this_cpu); #endif /* kDEBUG */ ops &= ~(1 << IPI_CPU_START); #ifdef ENTRY_SYS_CPUS p->state = STATE_RUNNING; #endif break; case IPI_CPU_STOP: #if (kDEBUG>=100) printk(KERN_DEBUG "CPU%d IPI_CPU_STOP\n",this_cpu); #endif /* kDEBUG */ ops &= ~(1 << IPI_CPU_STOP); #ifdef ENTRY_SYS_CPUS #else halt_processor(); #endif break; case IPI_CPU_TEST: #if (kDEBUG>=100) printk(KERN_DEBUG "CPU%d is alive!\n",this_cpu); #endif /* kDEBUG */ ops &= ~(1 << IPI_CPU_TEST); break; default: printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n", this_cpu, which); ops &= ~(1 << which); return; } /* Switch */ } /* while (ops) */ } return; } static inline void ipi_send(int cpu, enum ipi_message_type op) { struct cpuinfo_parisc *p = &cpu_data[cpu]; unsigned long flags; spin_lock_irqsave(&(p->lock),flags); p->pending_ipi |= 1 << op; __raw_writel(IRQ_OFFSET(IPI_IRQ), cpu_data[cpu].hpa); spin_unlock_irqrestore(&(p->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 (i = 0; i < smp_num_cpus; 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); } /** * 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; long timeout; static spinlock_t lock = SPIN_LOCK_UNLOCKED; data.func = func; data.info = info; data.wait = wait; atomic_set(&data.unstarted_count, smp_num_cpus - 1); atomic_set(&data.unfinished_count, smp_num_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); /* Wait for response */ timeout = jiffies + HZ; while ( (atomic_read (&data.unstarted_count) > 0) && time_before (jiffies, timeout) ) barrier (); /* We either got one or timed out. Release the lock */ mb(); smp_call_function_data = NULL; if (atomic_read (&data.unstarted_count) > 0) { printk(KERN_CRIT "SMP CALL FUNCTION TIMED OUT! (cpu=%d)\n", smp_processor_id()); return -ETIMEDOUT; } while (wait && atomic_read (&data.unfinished_count) > 0) barrier (); return 0; } /* * Setup routine for controlling SMP activation * * Command-line option of "nosmp" or "maxcpus=0" will disable SMP * activation entirely (the MPS table probe still happens, though). * * Command-line option of "maxcpus=", where is an integer * greater than 0, limits the maximum number of CPUs activated in * SMP mode to . */ static int __init nosmp(char *str) { max_cpus = 0; return 1; } __setup("nosmp", nosmp); static int __init maxcpus(char *str) { get_option(&str, &max_cpus); return 1; } __setup("maxcpus=", maxcpus); /* * Flush all other CPU's tlb and then mine. Do this with smp_call_function() * as we want to ensure all TLB's flushed before proceeding. */ extern void flush_tlb_all_local(void); void smp_flush_tlb_all(void) { smp_call_function((void (*)(void *))flush_tlb_all_local, NULL, 1, 1); flush_tlb_all_local(); } void smp_do_timer(struct pt_regs *regs) { int cpu = smp_processor_id(); struct cpuinfo_parisc *data = &cpu_data[cpu]; if (!--data->prof_counter) { data->prof_counter = data->prof_multiplier; update_process_times(user_mode(regs)); } } /* * 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/setup.c */ extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */ /* Set modes and Enable floating point coprocessor */ init_per_cpu(cpunum); disable_sr_hashing(); mb(); /* Well, support 2.4 linux scheme as well. */ if (test_and_set_bit(cpunum, (unsigned long *) (&cpu_online_map))) { 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, cpunum); init_IRQ(); /* make sure no IRQ's are enabled or pending */ } /* * 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) { extern void cpu_idle(void); /* arch/parisc/kernel/process.c */ int slave_id = cpu_now_booting; #if 0 void *istack; #endif smp_cpu_init(slave_id); #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(); local_irq_enable(); /* Interrupts have been off until now */ /* Slaves wait here until Big Poppa daddy say "jump" */ mb(); /* PARANOID */ while (!smp_commenced) ; mb(); /* PARANOID */ cpu_idle(); /* Wait for timer to schedule some work */ /* NOTREACHED */ panic("smp_callin() AAAAaaaaahhhh....\n"); } /* * Create the idle task for a new Slave CPU. DO NOT use kernel_thread() * because that could end up calling schedule(). If it did, the new idle * task could get scheduled before we had a chance to remove it from the * run-queue... */ static int fork_by_hand(void) { struct pt_regs regs; /* * don't care about the regs settings since * we'll never reschedule the forked task. */ return do_fork(CLONE_VM|CLONE_PID, 0, ®s, 0); } /* * Bring one cpu online. */ static int smp_boot_one_cpu(int cpuid, int cpunum) { 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 . . . */ if (fork_by_hand() < 0) panic("SMP: fork failed for CPU:%d", cpuid); idle = init_task.prev_task; if (!idle) panic("SMP: No idle process for CPU:%d", cpuid); task_set_cpu(idle, cpunum); /* manually schedule idle task */ del_from_runqueue(idle); unhash_process(idle); init_tasks[cpunum] = idle; /* Let _start know what logical CPU we're booting ** (offset into init_tasks[],cpu_data[]) */ cpu_now_booting = cpunum; /* ** boot strap code needs to know the task address since ** it also contains the process stack. */ smp_init_current_idle_task = idle ; mb(); /* ** This gets PDC to release the CPU from a very tight loop. ** See MEM_RENDEZ comments in head.S. */ __raw_writel(IRQ_OFFSET(TIMER_IRQ), cpu_data[cpunum].hpa); mb(); /* * OK, wait a bit for that CPU to finish staggering about. * Slave will set a bit when it reaches smp_cpu_init() and then * wait for smp_commenced to be 1. * Once we see the bit change, we can move on. */ for (timeout = 0; timeout < 10000; timeout++) { if(IS_LOGGED_IN(cpunum)) { /* Which implies Slave has started up */ cpu_now_booting = 0; smp_init_current_idle_task = NULL; goto alive ; } udelay(100); barrier(); } init_tasks[cpunum] = NULL; free_task_struct(idle); printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid); return -1; alive: /* Remember the Slave data */ #if (kDEBUG>=100) printk(KERN_DEBUG "SMP: CPU:%d (num %d) came alive after %ld _us\n", cpuid, cpunum, timeout * 100); #endif /* kDEBUG */ #ifdef ENTRY_SYS_CPUS cpu_data[cpunum].state = STATE_RUNNING; #endif return 0; } /* ** inventory.c:do_inventory() has already 'discovered' the additional CPU's. ** We are ready to wrest them from PDC's control now. ** Called by smp_init bring all the secondaries online and hold them. ** ** o Setup of the IPI irq handler is done in irq.c. ** o MEM_RENDEZ is initialzed in head.S:stext() ** */ void __init smp_boot_cpus(void) { int i, cpu_count = 1; unsigned long bogosum = loops_per_jiffy; /* Count Monarch */ /* REVISIT - assumes first CPU reported by PAT PDC is BSP */ int bootstrap_processor=cpu_data[0].cpuid; /* CPU ID of BSP */ /* Setup BSP mappings */ printk(KERN_DEBUG "SMP: bootstrap CPU ID is %d\n",bootstrap_processor); init_task.processor = bootstrap_processor; current->processor = bootstrap_processor; cpu_online_map = 1 << bootstrap_processor; /* Mark Boostrap processor as present */ current->active_mm = &init_mm; #ifdef ENTRY_SYS_CPUS cpu_data[0].state = STATE_RUNNING; #endif /* Nothing to do when told not to. */ if (max_cpus == 0) { printk(KERN_INFO "SMP mode deactivated.\n"); return; } if (max_cpus != -1) printk(KERN_INFO "Limiting CPUs to %d\n", max_cpus); /* We found more than one CPU.... */ if (boot_cpu_data.cpu_count > 1) { for (i = 0; i < NR_CPUS; i++) { if (cpu_data[i].cpuid == NO_PROC_ID || cpu_data[i].cpuid == bootstrap_processor) continue; if (smp_boot_one_cpu(cpu_data[i].cpuid, cpu_count) < 0) continue; bogosum += loops_per_jiffy; cpu_count++; /* Count good CPUs only... */ /* Bail when we've started as many CPUS as told to */ if (cpu_count == max_cpus) break; } } if (cpu_count == 1) { printk(KERN_INFO "SMP: Bootstrap processor only.\n"); } printk(KERN_INFO "SMP: Total %d of %d processors activated " "(%lu.%02lu BogoMIPS noticed).\n", cpu_count, boot_cpu_data.cpu_count, (bogosum + 25) / 5000, ((bogosum + 25) / 50) % 100); smp_num_cpus = cpu_count; #ifdef PER_CPU_IRQ_REGION ipi_init(); #endif return; } /* * Called from main.c by Monarch Processor. * After this, any CPU can schedule any task. */ void smp_commence(void) { smp_commenced = 1; mb(); return; } #ifdef ENTRY_SYS_CPUS /* Code goes along with: ** entry.s: ENTRY_NAME(sys_cpus) / * 215, for cpu stat * / */ int sys_cpus(int argc, char **argv) { int i,j=0; extern int current_pid(int cpu); if( argc > 2 ) { printk("sys_cpus:Only one argument supported\n"); return (-1); } if ( argc == 1 ){ #ifdef DUMP_MORE_STATE for(i=0; ipid)?"RUNNING ": "IDLING ",current->pid); #endif } else if ((argc==2) && !(strcmp(argv[1],"-s"))) { #ifdef DUMP_MORE_STATE printk("\nCPUSTATE CPUID\n"); for (i=0;ipid==0)?"RUNNING ":"IDLING "); #endif } else { printk("sys_cpus:Unknown request\n"); return (-1); } return 0; } #endif /* ENTRY_SYS_CPUS */ #ifdef CONFIG_PROC_FS int __init setup_profiling_timer(unsigned int multiplier) { return -EINVAL; } #endif