Initial import

1 files changed, 89 insertions, 0 deletions

diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
new file mode 100644
index 000000000..394e643d7
--- /dev/null
+++ b/arch/x86/kernel/irq_64.c
@@ -0,0 +1,89 @@
+/*
+ *	Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
+ *
+ * This file contains the lowest level x86_64-specific interrupt
+ * entry and irq statistics code. All the remaining irq logic is
+ * done by the generic kernel/irq/ code and in the
+ * x86_64-specific irq controller code. (e.g. i8259.c and
+ * io_apic.c.)
+ */
+
+#include <linux/kernel_stat.h>
+#include <linux/interrupt.h>
+#include <linux/seq_file.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/ftrace.h>
+#include <linux/uaccess.h>
+#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:
+ *
+ * Only check the stack in process context, because everything else
+ * runs on the big interrupt stacks. Checking reliably is too expensive,
+ * so we just check from interrupts.
+ */
+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);
+
+	if (user_mode(regs))
+		return;
+
+	if (regs->sp >= curbase + sizeof(struct thread_info) +
+				  sizeof(struct pt_regs) + STACK_TOP_MARGIN &&
+	    regs->sp <= curbase + THREAD_SIZE)
+		return;
+
+	irq_stack_top = (u64)this_cpu_ptr(irq_stack_union.irq_stack) +
+			STACK_TOP_MARGIN;
+	irq_stack_bottom = (u64)__this_cpu_read(irq_stack_ptr);
+	if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom)
+		return;
+
+	oist = this_cpu_ptr(&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;
+
+	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);
+
+	if (sysctl_panic_on_stackoverflow)
+		panic("low stack detected by irq handler - check messages\n");
+#endif
+}
+
+bool handle_irq(unsigned irq, struct pt_regs *regs)
+{
+	struct irq_desc *desc;
+
+	stack_overflow_check(regs);
+
+	desc = irq_to_desc(irq);
+	if (unlikely(!desc))
+		return false;
+
+	generic_handle_irq_desc(irq, desc);
+	return true;
+}