1 files changed, 179 insertions, 31 deletions

diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index e6faa3316bd..be8e1bde07a 100644
--- a/arch/x86/kernel/smp.c
+++ b/arch/x86/kernel/smp.c
@@ -2,7 +2,7 @@
  *	Intel SMP support routines.
  *
  *	(c) 1995 Alan Cox, Building #3 <alan@lxorguk.ukuu.org.uk>
- *	(c) 1998-99, 2000 Ingo Molnar <mingo@redhat.com>
+ *	(c) 1998-99, 2000, 2009 Ingo Molnar <mingo@redhat.com>
  *      (c) 2002,2003 Andi Kleen, SuSE Labs.
  *
  *	i386 and x86_64 integration by Glauber Costa <gcosta@redhat.com>
@@ -16,18 +16,21 @@
 #include <linux/mm.h>
 #include <linux/delay.h>
 #include <linux/spinlock.h>
+#include <linux/export.h>
 #include <linux/kernel_stat.h>
 #include <linux/mc146818rtc.h>
 #include <linux/cache.h>
 #include <linux/interrupt.h>
 #include <linux/cpu.h>
+#include <linux/gfp.h>
 
 #include <asm/mtrr.h>
 #include <asm/tlbflush.h>
 #include <asm/mmu_context.h>
 #include <asm/proto.h>
-#include <mach_ipi.h>
-#include <mach_apic.h>
+#include <asm/apic.h>
+#include <asm/nmi.h>
+#include <asm/trace/irq_vectors.h>
 /*
  *	Some notes on x86 processor bugs affecting SMP operation:
  *
@@ -107,6 +110,9 @@
  *	about nothing of note with C stepping upwards.
  */
 
+static atomic_t stopping_cpu = ATOMIC_INIT(-1);
+static bool smp_no_nmi_ipi = false;
+
 /*
  * this function sends a 'reschedule' IPI to another CPU.
  * it goes straight through and wastes no time serializing
@@ -118,12 +124,12 @@ static void native_smp_send_reschedule(int cpu)
 		WARN_ON(1);
 		return;
 	}
-	send_IPI_mask(cpumask_of(cpu), RESCHEDULE_VECTOR);
+	apic->send_IPI_mask(cpumask_of(cpu), RESCHEDULE_VECTOR);
 }
 
 void native_send_call_func_single_ipi(int cpu)
 {
-	send_IPI_mask(cpumask_of(cpu), CALL_FUNCTION_SINGLE_VECTOR);
+	apic->send_IPI_mask(cpumask_of(cpu), CALL_FUNCTION_SINGLE_VECTOR);
 }
 
 void native_send_call_func_ipi(const struct cpumask *mask)
@@ -131,7 +137,7 @@ void native_send_call_func_ipi(const struct cpumask *mask)
 	cpumask_var_t allbutself;
 
 	if (!alloc_cpumask_var(&allbutself, GFP_ATOMIC)) {
-		send_IPI_mask(mask, CALL_FUNCTION_VECTOR);
+		apic->send_IPI_mask(mask, CALL_FUNCTION_VECTOR);
 		return;
 	}
 
@@ -140,73 +146,215 @@ void native_send_call_func_ipi(const struct cpumask *mask)
 
 	if (cpumask_equal(mask, allbutself) &&
 	    cpumask_equal(cpu_online_mask, cpu_callout_mask))
-		send_IPI_allbutself(CALL_FUNCTION_VECTOR);
+		apic->send_IPI_allbutself(CALL_FUNCTION_VECTOR);
 	else
-		send_IPI_mask(mask, CALL_FUNCTION_VECTOR);
+		apic->send_IPI_mask(mask, CALL_FUNCTION_VECTOR);
 
 	free_cpumask_var(allbutself);
 }
 
+static int smp_stop_nmi_callback(unsigned int val, struct pt_regs *regs)
+{
+	/* We are registered on stopping cpu too, avoid spurious NMI */
+	if (raw_smp_processor_id() == atomic_read(&stopping_cpu))
+		return NMI_HANDLED;
+
+	stop_this_cpu(NULL);
+
+	return NMI_HANDLED;
+}
+
 /*
  * this function calls the 'stop' function on all other CPUs in the system.
  */
 
-static void native_smp_send_stop(void)
+asmlinkage __visible void smp_reboot_interrupt(void)
+{
+	ack_APIC_irq();
+	irq_enter();
+	stop_this_cpu(NULL);
+	irq_exit();
+}
+
+static void native_stop_other_cpus(int wait)
 {
 	unsigned long flags;
+	unsigned long timeout;
 
 	if (reboot_force)
 		return;
 
-	smp_call_function(stop_this_cpu, NULL, 0);
+	/*
+	 * Use an own vector here because smp_call_function
+	 * does lots of things not suitable in a panic situation.
+	 */
+
+	/*
+	 * We start by using the REBOOT_VECTOR irq.
+	 * The irq is treated as a sync point to allow critical
+	 * regions of code on other cpus to release their spin locks
+	 * and re-enable irqs.  Jumping straight to an NMI might
+	 * accidentally cause deadlocks with further shutdown/panic
+	 * code.  By syncing, we give the cpus up to one second to
+	 * finish their work before we force them off with the NMI.
+	 */
+	if (num_online_cpus() > 1) {
+		/* did someone beat us here? */
+		if (atomic_cmpxchg(&stopping_cpu, -1, safe_smp_processor_id()) != -1)
+			return;
+
+		/* sync above data before sending IRQ */
+		wmb();
+
+		apic->send_IPI_allbutself(REBOOT_VECTOR);
+
+		/*
+		 * Don't wait longer than a second if the caller
+		 * didn't ask us to wait.
+		 */
+		timeout = USEC_PER_SEC;
+		while (num_online_cpus() > 1 && (wait || timeout--))
+			udelay(1);
+	}
+	
+	/* if the REBOOT_VECTOR didn't work, try with the NMI */
+	if ((num_online_cpus() > 1) && (!smp_no_nmi_ipi))  {
+		if (register_nmi_handler(NMI_LOCAL, smp_stop_nmi_callback,
+					 NMI_FLAG_FIRST, "smp_stop"))
+			/* Note: we ignore failures here */
+			/* Hope the REBOOT_IRQ is good enough */
+			goto finish;
+
+		/* sync above data before sending IRQ */
+		wmb();
+
+		pr_emerg("Shutting down cpus with NMI\n");
+
+		apic->send_IPI_allbutself(NMI_VECTOR);
+
+		/*
+		 * Don't wait longer than a 10 ms if the caller
+		 * didn't ask us to wait.
+		 */
+		timeout = USEC_PER_MSEC * 10;
+		while (num_online_cpus() > 1 && (wait || timeout--))
+			udelay(1);
+	}
+
+finish:
 	local_irq_save(flags);
 	disable_local_APIC();
 	local_irq_restore(flags);
 }
 
 /*
- * Reschedule call back. Nothing to do,
- * all the work is done automatically when
- * we return from the interrupt.
+ * Reschedule call back.
  */
-void smp_reschedule_interrupt(struct pt_regs *regs)
+static inline void __smp_reschedule_interrupt(void)
 {
-	ack_APIC_irq();
 	inc_irq_stat(irq_resched_count);
+	scheduler_ipi();
+}
+
+__visible void smp_reschedule_interrupt(struct pt_regs *regs)
+{
+	ack_APIC_irq();
+	__smp_reschedule_interrupt();
+	/*
+	 * KVM uses this interrupt to force a cpu out of guest mode
+	 */
 }
 
-void smp_call_function_interrupt(struct pt_regs *regs)
+static inline void smp_entering_irq(void)
 {
 	ack_APIC_irq();
 	irq_enter();
+}
+
+__visible void smp_trace_reschedule_interrupt(struct pt_regs *regs)
+{
+	/*
+	 * Need to call irq_enter() before calling the trace point.
+	 * __smp_reschedule_interrupt() calls irq_enter/exit() too (in
+	 * scheduler_ipi(). This is OK, since those functions are allowed
+	 * to nest.
+	 */
+	smp_entering_irq();
+	trace_reschedule_entry(RESCHEDULE_VECTOR);
+	__smp_reschedule_interrupt();
+	trace_reschedule_exit(RESCHEDULE_VECTOR);
+	exiting_irq();
+	/*
+	 * KVM uses this interrupt to force a cpu out of guest mode
+	 */
+}
+
+static inline void __smp_call_function_interrupt(void)
+{
 	generic_smp_call_function_interrupt();
 	inc_irq_stat(irq_call_count);
-	irq_exit();
 }
 
-void smp_call_function_single_interrupt(struct pt_regs *regs)
+__visible void smp_call_function_interrupt(struct pt_regs *regs)
+{
+	smp_entering_irq();
+	__smp_call_function_interrupt();
+	exiting_irq();
+}
+
+__visible void smp_trace_call_function_interrupt(struct pt_regs *regs)
+{
+	smp_entering_irq();
+	trace_call_function_entry(CALL_FUNCTION_VECTOR);
+	__smp_call_function_interrupt();
+	trace_call_function_exit(CALL_FUNCTION_VECTOR);
+	exiting_irq();
+}
+
+static inline void __smp_call_function_single_interrupt(void)
 {
-	ack_APIC_irq();
-	irq_enter();
 	generic_smp_call_function_single_interrupt();
 	inc_irq_stat(irq_call_count);
-	irq_exit();
 }
 
+__visible void smp_call_function_single_interrupt(struct pt_regs *regs)
+{
+	smp_entering_irq();
+	__smp_call_function_single_interrupt();
+	exiting_irq();
+}
+
+__visible void smp_trace_call_function_single_interrupt(struct pt_regs *regs)
+{
+	smp_entering_irq();
+	trace_call_function_single_entry(CALL_FUNCTION_SINGLE_VECTOR);
+	__smp_call_function_single_interrupt();
+	trace_call_function_single_exit(CALL_FUNCTION_SINGLE_VECTOR);
+	exiting_irq();
+}
+
+static int __init nonmi_ipi_setup(char *str)
+{
+	smp_no_nmi_ipi = true;
+	return 1;
+}
+
+__setup("nonmi_ipi", nonmi_ipi_setup);
+
 struct smp_ops smp_ops = {
-	.smp_prepare_boot_cpu = native_smp_prepare_boot_cpu,
-	.smp_prepare_cpus = native_smp_prepare_cpus,
-	.smp_cpus_done = native_smp_cpus_done,
+	.smp_prepare_boot_cpu	= native_smp_prepare_boot_cpu,
+	.smp_prepare_cpus	= native_smp_prepare_cpus,
+	.smp_cpus_done		= native_smp_cpus_done,
 
-	.smp_send_stop = native_smp_send_stop,
-	.smp_send_reschedule = native_smp_send_reschedule,
+	.stop_other_cpus	= native_stop_other_cpus,
+	.smp_send_reschedule	= native_smp_send_reschedule,
 
-	.cpu_up = native_cpu_up,
-	.cpu_die = native_cpu_die,
-	.cpu_disable = native_cpu_disable,
-	.play_dead = native_play_dead,
+	.cpu_up			= native_cpu_up,
+	.cpu_die		= native_cpu_die,
+	.cpu_disable		= native_cpu_disable,
+	.play_dead		= native_play_dead,
 
-	.send_call_func_ipi = native_send_call_func_ipi,
+	.send_call_func_ipi	= native_send_call_func_ipi,
 	.send_call_func_single_ipi = native_send_call_func_single_ipi,
 };
 EXPORT_SYMBOL_GPL(smp_ops);