smp.c

一个2.4.21版本的嵌入式linux内核

/*
 * 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 */
	(void) 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)))
	{
		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, 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, &regs, 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; i<NR_CPUS; i++) {
			int cpus_per_line = 4;
			if(IS_LOGGED_IN(i)) {
				if (j++ % cpus_per_line)
					printk(" %3d",i);
				else
					printk("\n %3d",i);
			}
		}
		printk("\n"); 
#else
	    	printk("\n 0\n"); 
#endif
	} else if((argc==2) && !(strcmp(argv[1],"-l"))) {
		printk("\nCPUSTATE  TASK CPUNUM CPUID HARDCPU(HPA)\n");
#ifdef DUMP_MORE_STATE
		for(i=0;i<NR_CPUS;i++) {
			if (!IS_LOGGED_IN(i))
				continue;
			if (cpu_data[i].cpuid != NO_PROC_ID) {
				switch(cpu_data[i].state) {
					case STATE_RENDEZVOUS:
						printk("RENDEZVS ");
						break;
					case STATE_RUNNING:
						printk((current_pid(i)!=0) ? "RUNNING  " : "IDLING   ");
						break;
					case STATE_STOPPED:
						printk("STOPPED  ");
						break;
					case STATE_HALTED:
						printk("HALTED   ");
						break;
					default:
						printk("%08x?", cpu_data[i].state);
						break;
				}
				if(IS_LOGGED_IN(i)) {
					printk(" %4d",current_pid(i));
				}	
				printk(" %6d",cpu_number_map(i));
				printk(" %5d",i);
				printk(" 0x%lx\n",cpu_data[i].hpa);
			}	
		}
#else
		printk("\n%s  %4d      0     0 --------",
			(current->pid)?"RUNNING ": "IDLING  ",current->pid); 
#endif
	} else if ((argc==2) && !(strcmp(argv[1],"-s"))) { 
#ifdef DUMP_MORE_STATE
     		printk("\nCPUSTATE   CPUID\n");
		for (i=0;i<NR_CPUS;i++) {
			if (!IS_LOGGED_IN(i))
				continue;
			if (cpu_data[i].cpuid != NO_PROC_ID) {
				switch(cpu_data[i].state) {
					case STATE_RENDEZVOUS:
						printk("RENDEZVS");break;
					case STATE_RUNNING:
						printk((current_pid(i)!=0) ? "RUNNING " : "IDLING");
						break;
					case STATE_STOPPED:
						printk("STOPPED ");break;
					case STATE_HALTED:
						printk("HALTED  ");break;
					default:
				}
				printk("  %5d\n",i);
			}	
		}
#else
		printk("\n%s    CPU0",(current->pid==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