1 files changed, 43 insertions, 113 deletions

diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
index 63c88e6ec02..4d1c746892e 100644
--- a/arch/x86/kernel/irq_64.c
+++ b/arch/x86/kernel/irq_64.c
@@ -18,6 +18,15 @@
 #include <linux/smp.h>
 #include <asm/io_apic.h>
 #include <asm/idle.h>
+#include <asm/apic.h>
+
+DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
+EXPORT_PER_CPU_SYMBOL(irq_stat);
+
+DEFINE_PER_CPU(struct pt_regs *, irq_regs);
+EXPORT_PER_CPU_SYMBOL(irq_regs);
+
+int sysctl_panic_on_stackoverflow;
 
 /*
  * Probabilistic stack overflow check:
@@ -29,131 +38,52 @@
 static inline void stack_overflow_check(struct pt_regs *regs)
 {
 #ifdef CONFIG_DEBUG_STACKOVERFLOW
+#define STACK_TOP_MARGIN	128
+	struct orig_ist *oist;
+	u64 irq_stack_top, irq_stack_bottom;
+	u64 estack_top, estack_bottom;
 	u64 curbase = (u64)task_stack_page(current);
 
-	WARN_ONCE(regs->sp >= curbase &&
-		  regs->sp <= curbase + THREAD_SIZE &&
-		  regs->sp <  curbase + sizeof(struct thread_info) +
-					sizeof(struct pt_regs) + 128,
-
-		  "do_IRQ: %s near stack overflow (cur:%Lx,sp:%lx)\n",
-			current->comm, curbase, regs->sp);
-#endif
-}
-
-/*
- * do_IRQ handles all normal device IRQ's (the special
- * SMP cross-CPU interrupts have their own specific
- * handlers).
- */
-asmlinkage unsigned int __irq_entry do_IRQ(struct pt_regs *regs)
-{
-	struct pt_regs *old_regs = set_irq_regs(regs);
-	struct irq_desc *desc;
-
-	/* high bit used in ret_from_ code  */
-	unsigned vector = ~regs->orig_ax;
-	unsigned irq;
-
-	exit_idle();
-	irq_enter();
-	irq = __get_cpu_var(vector_irq)[vector];
+	if (user_mode_vm(regs))
+		return;
 
-	stack_overflow_check(regs);
+	if (regs->sp >= curbase + sizeof(struct thread_info) +
+				  sizeof(struct pt_regs) + STACK_TOP_MARGIN &&
+	    regs->sp <= curbase + THREAD_SIZE)
+		return;
 
-	desc = irq_to_desc(irq);
-	if (likely(desc))
-		generic_handle_irq_desc(irq, desc);
-	else {
-		if (!disable_apic)
-			ack_APIC_irq();
+	irq_stack_top = (u64)__get_cpu_var(irq_stack_union.irq_stack) +
+			STACK_TOP_MARGIN;
+	irq_stack_bottom = (u64)__get_cpu_var(irq_stack_ptr);
+	if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom)
+		return;
 
-		if (printk_ratelimit())
-			printk(KERN_EMERG "%s: %d.%d No irq handler for vector\n",
-				__func__, smp_processor_id(), vector);
-	}
+	oist = &__get_cpu_var(orig_ist);
+	estack_top = (u64)oist->ist[0] - EXCEPTION_STKSZ + STACK_TOP_MARGIN;
+	estack_bottom = (u64)oist->ist[N_EXCEPTION_STACKS - 1];
+	if (regs->sp >= estack_top && regs->sp <= estack_bottom)
+		return;
 
-	irq_exit();
+	WARN_ONCE(1, "do_IRQ(): %s has overflown the kernel stack (cur:%Lx,sp:%lx,irq stk top-bottom:%Lx-%Lx,exception stk top-bottom:%Lx-%Lx)\n",
+		current->comm, curbase, regs->sp,
+		irq_stack_top, irq_stack_bottom,
+		estack_top, estack_bottom);
 
-	set_irq_regs(old_regs);
-	return 1;
+	if (sysctl_panic_on_stackoverflow)
+		panic("low stack detected by irq handler - check messages\n");
+#endif
 }
 
-#ifdef CONFIG_HOTPLUG_CPU
-/* A cpu has been removed from cpu_online_mask.  Reset irq affinities. */
-void fixup_irqs(void)
+bool handle_irq(unsigned irq, struct pt_regs *regs)
 {
-	unsigned int irq;
-	static int warned;
 	struct irq_desc *desc;
 
-	for_each_irq_desc(irq, desc) {
-		int break_affinity = 0;
-		int set_affinity = 1;
-		const struct cpumask *affinity;
-
-		if (!desc)
-			continue;
-		if (irq == 2)
-			continue;
-
-		/* interrupt's are disabled at this point */
-		spin_lock(&desc->lock);
-
-		affinity = &desc->affinity;
-		if (!irq_has_action(irq) ||
-		    cpumask_equal(affinity, cpu_online_mask)) {
-			spin_unlock(&desc->lock);
-			continue;
-		}
-
-		if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
-			break_affinity = 1;
-			affinity = cpu_all_mask;
-		}
-
-		if (desc->chip->mask)
-			desc->chip->mask(irq);
-
-		if (desc->chip->set_affinity)
-			desc->chip->set_affinity(irq, affinity);
-		else if (!(warned++))
-			set_affinity = 0;
-
-		if (desc->chip->unmask)
-			desc->chip->unmask(irq);
-
-		spin_unlock(&desc->lock);
-
-		if (break_affinity && set_affinity)
-			printk("Broke affinity for irq %i\n", irq);
-		else if (!set_affinity)
-			printk("Cannot set affinity for irq %i\n", irq);
-	}
-
-	/* That doesn't seem sufficient.  Give it 1ms. */
-	local_irq_enable();
-	mdelay(1);
-	local_irq_disable();
-}
-#endif
-
-extern void call_softirq(void);
-
-asmlinkage void do_softirq(void)
-{
-	__u32 pending;
-	unsigned long flags;
+	stack_overflow_check(regs);
 
-	if (in_interrupt())
-		return;
+	desc = irq_to_desc(irq);
+	if (unlikely(!desc))
+		return false;
 
-	local_irq_save(flags);
-	pending = local_softirq_pending();
-	/* Switch to interrupt stack */
-	if (pending) {
-		call_softirq();
-		WARN_ON_ONCE(softirq_count());
-	}
-	local_irq_restore(flags);
+	generic_handle_irq_desc(irq, desc);
+	return true;
 }