[PATCH] Remove global cli stuff for x86-64

Straightforward merge from i386: remove support for global cli for
x86-64

arch/x86_64/kernel/irq.c

@@ -180,250 +180,12 @@ int show_interrupts(struct seq_file *p, void *v)
 	return 0;
 }
 
-/*
- * Global interrupt locks for SMP. Allow interrupts to come in on any
- * CPU, yet make cli/sti act globally to protect critical regions..
- */
-
 #ifdef CONFIG_SMP
-unsigned char global_irq_holder = NO_PROC_ID;
-unsigned volatile long global_irq_lock; /* pendantic: long for set_bit --RR */
-
-extern void show_stack(unsigned long* esp);
-
-
-/* XXX: this unfortunately doesn't support irqstacks currently, should check the other PDAs */
-static void show(char * str)
-{
-	int i;
-	int cpu = smp_processor_id();
-
-	printk("\n%s, CPU %d:\n", str, cpu);
-	printk("irq:  %d [",irqs_running());
-	for(i=0;i < smp_num_cpus;i++)
-		printk(" %d",local_irq_count(i));
-	printk(" ]\nbh:   %d [",spin_is_locked(&global_bh_lock) ? 1 : 0);
-	for(i=0;i < smp_num_cpus;i++)
-		printk(" %d",local_bh_count(i));
-
-	printk(" ]\nStack dumps:");
-	for(i = 0; i < smp_num_cpus; i++) {
-		unsigned long esp;
-		if (i == cpu)
-			continue;
-		printk("\nCPU %d:",i);
-		esp = init_tss[i].rsp0;
-		if (!esp) {
-			/* tss->esp0 is set to NULL in cpu_init(),
-			 * it's initialized when the cpu returns to user
-			 * space. -- manfreds
-			 */
-			printk(" <unknown> ");
-			continue;
-		}
-		esp &= ~(THREAD_SIZE-1);
-		esp += sizeof(struct thread_info);
-		show_stack((void*)esp);
- 	}
-	printk("\nCPU %d:",cpu);
-	show_stack(NULL);
-	printk("\n");
-}
-	
-#define MAXCOUNT 100000000
-
-/*
- * I had a lockup scenario where a tight loop doing
- * spin_unlock()/spin_lock() on CPU#1 was racing with
- * spin_lock() on CPU#0. CPU#0 should have noticed spin_unlock(), but
- * apparently the spin_unlock() information did not make it
- * through to CPU#0 ... nasty, is this by design, do we have to limit
- * 'memory update oscillation frequency' artificially like here?
- *
- * Such 'high frequency update' races can be avoided by careful design, but
- * some of our major constructs like spinlocks use similar techniques,
- * it would be nice to clarify this issue. Set this define to 0 if you
- * want to check whether your system freezes.  I suspect the delay done
- * by SYNC_OTHER_CORES() is in correlation with 'snooping latency', but
- * i thought that such things are guaranteed by design, since we use
- * the 'LOCK' prefix.
- */
-#define SUSPECTED_CPU_OR_CHIPSET_BUG_WORKAROUND 0
-
-#if SUSPECTED_CPU_OR_CHIPSET_BUG_WORKAROUND
-# define SYNC_OTHER_CORES(x) udelay(x+1)
-#else
-/*
- * We have to allow irqs to arrive between local_irq_enable and local_irq_disable
- */
-# define SYNC_OTHER_CORES(x) __asm__ __volatile__ ("nop")
-#endif
-
-static inline void wait_on_irq(int cpu)
-{
-	int count = MAXCOUNT;
-
-	for (;;) {
-
-		/*
-		 * Wait until all interrupts are gone. Wait
-		 * for bottom half handlers unless we're
-		 * already executing in one..
-		 */
-		if (!irqs_running())
-			if (local_bh_count(cpu) || !spin_is_locked(&global_bh_lock))
-				break;
-
-		/* Duh, we have to loop. Release the lock to avoid deadlocks */
-		clear_bit(0,&global_irq_lock);
-
-		for (;;) {
-			if (!--count) {
-				show("wait_on_irq");
-				count = ~0;
-			}
-			local_irq_enable();
-			SYNC_OTHER_CORES(cpu);
-			local_irq_disable();
-			if (irqs_running())
-				continue;
-			if (global_irq_lock)
-				continue;
-			if (!local_bh_count(cpu) && spin_is_locked(&global_bh_lock))
-				continue;
-			if (!test_and_set_bit(0,&global_irq_lock))
-				break;
-		}
-	}
-}
-
-/*
- * This is called when we want to synchronize with
- * interrupts. We may for example tell a device to
- * stop sending interrupts: but to make sure there
- * are no interrupts that are executing on another
- * CPU we need to call this function.
- */
-void synchronize_irq(void)
+inline void synchronize_irq(unsigned int irq)
 {
-	if (irqs_running()) {
-		/* Stupid approach */
-		cli();
-		sti();
-	}
-}
-
-static inline void get_irqlock(int cpu)
-{
-	if (test_and_set_bit(0,&global_irq_lock)) {
-		/* do we already hold the lock? */
-		if ((unsigned char) cpu == global_irq_holder)
-			return;
-		/* Uhhuh.. Somebody else got it. Wait.. */
-		do {
-			do {
-				rep_nop();
-			} while (test_bit(0,&global_irq_lock));
-		} while (test_and_set_bit(0,&global_irq_lock));		
-	}
-	/* 
-	 * We also to make sure that nobody else is running
-	 * in an interrupt context. 
-	 */
-	wait_on_irq(cpu);
-
-	/*
-	 * Ok, finally..
-	 */
-	global_irq_holder = cpu;
-}
-
-#define EFLAGS_IF_SHIFT 9
-
-/*
- * A global "cli()" while in an interrupt context
- * turns into just a local cli(). Interrupts
- * should use spinlocks for the (very unlikely)
- * case that they ever want to protect against
- * each other.
- *
- * If we already have local interrupts disabled,
- * this will not turn a local disable into a
- * global one (problems with spinlocks: this makes
- * save_flags+cli+sti usable inside a spinlock).
- */
-void __global_cli(void)
-{
-	unsigned long flags;
-
-	local_save_flags(flags);
-	if (flags & (1 << EFLAGS_IF_SHIFT)) {
-		int cpu = smp_processor_id();
-		local_irq_disable();
-		if (!local_irq_count(cpu))
-			get_irqlock(cpu);
-	}
-}
-
-void __global_sti(void)
-{
-	int cpu = smp_processor_id();
-
-	if (!local_irq_count(cpu))
-		release_irqlock(cpu);
-	local_irq_enable();
-}
-
-/*
- * SMP flags value to restore to:
- * 0 - global cli
- * 1 - global sti
- * 2 - local cli
- * 3 - local sti
- */
-unsigned long __global_save_flags(void)
-{
-	int retval;
-	int local_enabled;
-	unsigned long flags;
-	int cpu = smp_processor_id();
-
-	local_save_flags(flags);
-	local_enabled = (flags >> EFLAGS_IF_SHIFT) & 1;
-	/* default to local */
-	retval = 2 + local_enabled;
-
-	/* check for global flags if we're not in an interrupt */
-	if (!local_irq_count(cpu)) {
-		if (local_enabled)
-			retval = 1;
-		if (global_irq_holder == cpu)
-			retval = 0;
-	}
-	return retval;
-}
-
-void __global_restore_flags(unsigned long flags)
-{
-	switch (flags) {
-	case 0:
-		__global_cli();
-		break;
-	case 1:
-		__global_sti();
-		break;
-	case 2:
-		local_irq_disable();
-		break;
-	case 3:
-		local_irq_enable();
-		break;
-	default:
-		printk("global_restore_flags: %08lx (%08lx)\n",
-			flags, (&flags)[-1]);
-	}
+	while (irq_desc[irq].status & IRQ_INPROGRESS)
+		cpu_relax();
 }
-
 #endif
 
 /*
@@ -506,13 +268,7 @@ inline void disable_irq_nosync(unsigned int irq)
 void disable_irq(unsigned int irq)
 {
 	disable_irq_nosync(irq);
-
-	if (!local_irq_count(smp_processor_id())) {
-		do {
-			barrier();
-			cpu_relax();
-		} while (irq_desc[irq].status & IRQ_INPROGRESS);
-	}
+	synchronize_irq(irq);
 }
 
 /**