smp.c

该文件是rt_linux

		printk("CPU[%d]: mondo stuckage result[%016lx]\n",
		       smp_processor_id(), result);
	} else {
		udelay(2);
		goto again;
	}
}

static __inline__ void spitfire_xcall_deliver(u64 data0, u64 data1, u64 data2, unsigned long mask)
{
	int ncpus = smp_num_cpus - 1;
	int i;
	u64 pstate;

	__asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate));
	for (i = 0; (i < NR_CPUS) && ncpus; i++) {
		if (mask & (1UL << i)) {
			spitfire_xcall_helper(data0, data1, data2, pstate, i);
			ncpus--;
		}
	}
}

/* Cheetah now allows to send the whole 64-bytes of data in the interrupt
 * packet, but we have no use for that.  However we do take advantage of
 * the new pipelining feature (ie. dispatch to multiple cpus simultaneously).
 */
#if NR_CPUS > 32
#error Fixup cheetah_xcall_deliver Dave...
#endif
static void cheetah_xcall_deliver(u64 data0, u64 data1, u64 data2, unsigned long mask)
{
	u64 pstate;
	int nack_busy_id;

	if (!mask)
		return;

	__asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate));

retry:
	__asm__ __volatile__("wrpr %0, %1, %%pstate\n\t"
			     : : "r" (pstate), "i" (PSTATE_IE));

	/* Setup the dispatch data registers. */
	__asm__ __volatile__("stxa	%0, [%3] %6\n\t"
			     "stxa	%1, [%4] %6\n\t"
			     "stxa	%2, [%5] %6\n\t"
			     "membar	#Sync\n\t"
			     : /* no outputs */
			     : "r" (data0), "r" (data1), "r" (data2),
			       "r" (0x40), "r" (0x50), "r" (0x60),
			       "i" (ASI_INTR_W));

	nack_busy_id = 0;
	{
		int i, ncpus = smp_num_cpus - 1;

		for (i = 0; (i < NR_CPUS) && ncpus; i++) {
			if (mask & (1UL << i)) {
				u64 target = (i << 14) | 0x70;

				target |= (nack_busy_id++ << 24);
				__asm__ __volatile__("stxa	%%g0, [%0] %1\n\t"
						     "membar	#Sync\n\t"
						     : /* no outputs */
						     : "r" (target), "i" (ASI_INTR_W));
				ncpus--;
			}
		}
	}

	/* Now, poll for completion. */
	{
		u64 dispatch_stat;
		long stuck;

		stuck = 100000 * nack_busy_id;
		do {
			__asm__ __volatile__("ldxa	[%%g0] %1, %0"
					     : "=r" (dispatch_stat)
					     : "i" (ASI_INTR_DISPATCH_STAT));
			if (dispatch_stat == 0UL) {
				__asm__ __volatile__("wrpr %0, 0x0, %%pstate"
						     : : "r" (pstate));
				return;
			}
			if (!--stuck)
				break;
		} while (dispatch_stat & 0x5555555555555555UL);

		__asm__ __volatile__("wrpr %0, 0x0, %%pstate"
				     : : "r" (pstate));

		if ((dispatch_stat & ~(0x5555555555555555UL)) == 0) {
			/* Busy bits will not clear, continue instead
			 * of freezing up on this cpu.
			 */
			printk("CPU[%d]: mondo stuckage result[%016lx]\n",
			       smp_processor_id(), dispatch_stat);
		} else {
			int i, this_busy_nack = 0;

			/* Delay some random time with interrupts enabled
			 * to prevent deadlock.
			 */
			udelay(2 * nack_busy_id);

			/* Clear out the mask bits for cpus which did not
			 * NACK us.
			 */
			for (i = 0; i < NR_CPUS; i++) {
				if (mask & (1UL << i)) {
					if ((dispatch_stat & (0x2 << this_busy_nack)) == 0)
						mask &= ~(1UL << i);
					this_busy_nack += 2;
				}
			}

			goto retry;
		}
	}
}

/* Send cross call to all processors mentioned in MASK
 * except self.
 */
static void smp_cross_call_masked(unsigned long *func, u32 ctx, u64 data1, u64 data2, unsigned long mask)
{
	if (smp_processors_ready) {
		u64 data0 = (((u64)ctx)<<32 | (((u64)func) & 0xffffffff));

		mask &= ~(1UL<<smp_processor_id());

		if (tlb_type == spitfire)
			spitfire_xcall_deliver(data0, data1, data2, mask);
		else
			cheetah_xcall_deliver(data0, data1, data2, mask);

		/* NOTE: Caller runs local copy on master. */
	}
}

/* Send cross call to all processors except self. */
#define smp_cross_call(func, ctx, data1, data2) \
	smp_cross_call_masked(func, ctx, data1, data2, cpu_present_map)

struct call_data_struct {
	void (*func) (void *info);
	void *info;
	atomic_t finished;
	int wait;
};

static spinlock_t call_lock = SPIN_LOCK_UNLOCKED;
static struct call_data_struct *call_data;

extern unsigned long xcall_call_function;

int smp_call_function(void (*func)(void *info), void *info,
		      int nonatomic, int wait)
{
	struct call_data_struct data;
	int cpus = smp_num_cpus - 1;
	long timeout;

	if (!cpus)
		return 0;

	data.func = func;
	data.info = info;
	atomic_set(&data.finished, 0);
	data.wait = wait;

	spin_lock_bh(&call_lock);

	call_data = &data;

	smp_cross_call(&xcall_call_function, 0, 0, 0);

	/* 
	 * Wait for other cpus to complete function or at
	 * least snap the call data.
	 */
	timeout = 1000000;
	while (atomic_read(&data.finished) != cpus) {
		if (--timeout <= 0)
			goto out_timeout;
		barrier();
		udelay(1);
	}

	spin_unlock_bh(&call_lock);

	return 0;

out_timeout:
	spin_unlock_bh(&call_lock);
	printk("XCALL: Remote cpus not responding, ncpus=%d finished=%d\n",
	       smp_num_cpus - 1, atomic_read(&data.finished));
	return 0;
}

void smp_call_function_client(int irq, struct pt_regs *regs)
{
	void (*func) (void *info) = call_data->func;
	void *info = call_data->info;

	clear_softint(1 << irq);
	if (call_data->wait) {
		/* let initiator proceed only after completion */
		func(info);
		atomic_inc(&call_data->finished);
	} else {
		/* let initiator proceed after getting data */
		atomic_inc(&call_data->finished);
		func(info);
	}
}

extern unsigned long xcall_flush_tlb_page;
extern unsigned long xcall_flush_tlb_mm;
extern unsigned long xcall_flush_tlb_range;
extern unsigned long xcall_flush_tlb_all_spitfire;
extern unsigned long xcall_flush_tlb_all_cheetah;
extern unsigned long xcall_flush_cache_all_spitfire;
extern unsigned long xcall_report_regs;
extern unsigned long xcall_receive_signal;
extern unsigned long xcall_flush_dcache_page_cheetah;
extern unsigned long xcall_flush_dcache_page_spitfire;

#ifdef CONFIG_DEBUG_DCFLUSH
extern atomic_t dcpage_flushes;
extern atomic_t dcpage_flushes_xcall;
#endif

static __inline__ void __local_flush_dcache_page(struct page *page)
{
#if (L1DCACHE_SIZE > PAGE_SIZE)
	__flush_dcache_page(page->virtual,
			    ((tlb_type == spitfire) &&
			     page->mapping != NULL));
#else
	if (page->mapping != NULL &&
	    tlb_type == spitfire)
		__flush_icache_page(__pa(page->virtual));
#endif
}

void smp_flush_dcache_page_impl(struct page *page, int cpu)
{
	if (smp_processors_ready) {
		unsigned long mask = 1UL << cpu;

#ifdef CONFIG_DEBUG_DCFLUSH
		atomic_inc(&dcpage_flushes);
#endif
		if (cpu == smp_processor_id()) {
			__local_flush_dcache_page(page);
		} else if ((cpu_present_map & mask) != 0) {
			u64 data0;

			if (tlb_type == spitfire) {
				data0 = ((u64)&xcall_flush_dcache_page_spitfire);
				if (page->mapping != NULL)
					data0 |= ((u64)1 << 32);
				spitfire_xcall_deliver(data0,
						       __pa(page->virtual),
						       (u64) page->virtual,
						       mask);
			} else {
				data0 = ((u64)&xcall_flush_dcache_page_cheetah);
				cheetah_xcall_deliver(data0,
						      __pa(page->virtual),
						      0, mask);
			}
#ifdef CONFIG_DEBUG_DCFLUSH
			atomic_inc(&dcpage_flushes_xcall);
#endif
		}
	}
}

void flush_dcache_page_all(struct mm_struct *mm, struct page *page)
{
	if (smp_processors_ready) {
		unsigned long mask = cpu_present_map & ~(1UL << smp_processor_id());
		u64 data0;

#ifdef CONFIG_DEBUG_DCFLUSH
		atomic_inc(&dcpage_flushes);
#endif
		if (mask == 0UL)
			goto flush_self;
		if (tlb_type == spitfire) {
			data0 = ((u64)&xcall_flush_dcache_page_spitfire);
			if (page->mapping != NULL)
				data0 |= ((u64)1 << 32);
			spitfire_xcall_deliver(data0,
					       __pa(page->virtual),
					       (u64) page->virtual,
					       mask);
		} else {
			data0 = ((u64)&xcall_flush_dcache_page_cheetah);
			cheetah_xcall_deliver(data0,
					      __pa(page->virtual),
					      0, mask);
		}
#ifdef CONFIG_DEBUG_DCFLUSH
		atomic_inc(&dcpage_flushes_xcall);
#endif
	flush_self:
		__local_flush_dcache_page(page);
	}
}

void smp_receive_signal(int cpu)
{
	if (smp_processors_ready) {
		unsigned long mask = 1UL << cpu;

		if ((cpu_present_map & mask) != 0) {
			u64 data0 = (((u64)&xcall_receive_signal) & 0xffffffff);

			if (tlb_type == spitfire)
				spitfire_xcall_deliver(data0, 0, 0, mask);
			else
				cheetah_xcall_deliver(data0, 0, 0, mask);
		}
	}
}

void smp_receive_signal_client(int irq, struct pt_regs *regs)
{
	/* Just return, rtrap takes care of the rest. */
	clear_softint(1 << irq);
}

void smp_report_regs(void)
{
	smp_cross_call(&xcall_report_regs, 0, 0, 0);
}

void smp_flush_cache_all(void)
{
	/* Cheetah need do nothing. */
	if (tlb_type == spitfire) {
		smp_cross_call(&xcall_flush_cache_all_spitfire, 0, 0, 0);
		__flush_cache_all();
	}
}

void smp_flush_tlb_all(void)
{
	if (tlb_type == spitfire)
		smp_cross_call(&xcall_flush_tlb_all_spitfire, 0, 0, 0);
	else
		smp_cross_call(&xcall_flush_tlb_all_cheetah, 0, 0, 0);
	__flush_tlb_all();
}

/* We know that the window frames of the user have been flushed
 * to the stack before we get here because all callers of us
 * are flush_tlb_*() routines, and these run after flush_cache_*()
 * which performs the flushw.
 *
 * The SMP TLB coherency scheme we use works as follows:
 *
 * 1) mm->cpu_vm_mask is a bit mask of which cpus an address
 *    space has (potentially) executed on, this is the heuristic
 *    we use to avoid doing cross calls.
 *
 *    Also, for flushing from kswapd and also for clones, we
 *    use cpu_vm_mask as the list of cpus to make run the TLB.
 *
 * 2) TLB context numbers are shared globally across all processors
 *    in the system, this allows us to play several games to avoid
 *    cross calls.
 *
 *    One invariant is that when a cpu switches to a process, and
 *    that processes tsk->active_mm->cpu_vm_mask does not have the
 *    current cpu's bit set, that tlb context is flushed locally.
 *
 *    If the address space is non-shared (ie. mm->count == 1) we avoid
 *    cross calls when we want to flush the currently running process's
 *    tlb state.  This is done by clearing all cpu bits except the current
 *    processor's in current->active_mm->cpu_vm_mask and performing the
 *    flush locally only.  This will force any subsequent cpus which run
 *    this task to flush the context from the local tlb if the process
 *    migrates to another cpu (again).
 *
 * 3) For shared address spaces (threads) and swapping we bite the
 *    bullet for most cases and perform the cross call (but only to
 *    the cpus listed in cpu_vm_mask).
 *
 *    The performance gain from "optimizing" away the cross call for threads is
 *    questionable (in theory the big win for threads is the massive sharing of
 *    address space state across processors).
 */
void smp_flush_tlb_mm(struct mm_struct *mm)
{