13 files changed, 317 insertions, 64 deletions

diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 612ed3435c0..88d99ea7772 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -16,6 +16,8 @@ CFLAGS_REMOVE_ftrace.o = -pg
 CFLAGS_REMOVE_early_printk.o = -pg
 endif
 
+CFLAGS_irq.o := -I$(src)/../include/asm/trace
+
 obj-y			:= process_$(BITS).o signal.o entry_$(BITS).o
 obj-y			+= traps.o irq.o irq_$(BITS).o dumpstack_$(BITS).o
 obj-y			+= time.o ioport.o ldt.o dumpstack.o nmi.o
@@ -103,6 +105,7 @@ obj-$(CONFIG_OF)			+= devicetree.o
 obj-$(CONFIG_UPROBES)			+= uprobes.o
 
 obj-$(CONFIG_PERF_EVENTS)		+= perf_regs.o
+obj-$(CONFIG_TRACING)			+= tracepoint.o
 
 ###
 # 64 bit specific files
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 1600b1ca4f0..99663b59123 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -35,6 +35,7 @@
 #include <linux/smp.h>
 #include <linux/mm.h>
 
+#include <asm/trace/irq_vectors.h>
 #include <asm/irq_remapping.h>
 #include <asm/perf_event.h>
 #include <asm/x86_init.h>
@@ -919,17 +920,35 @@ void __irq_entry smp_apic_timer_interrupt(struct pt_regs *regs)
 	/*
 	 * NOTE! We'd better ACK the irq immediately,
 	 * because timer handling can be slow.
+	 *
+	 * update_process_times() expects us to have done irq_enter().
+	 * Besides, if we don't timer interrupts ignore the global
+	 * interrupt lock, which is the WrongThing (tm) to do.
 	 */
-	ack_APIC_irq();
+	entering_ack_irq();
+	local_apic_timer_interrupt();
+	exiting_irq();
+
+	set_irq_regs(old_regs);
+}
+
+void __irq_entry smp_trace_apic_timer_interrupt(struct pt_regs *regs)
+{
+	struct pt_regs *old_regs = set_irq_regs(regs);
+
 	/*
+	 * NOTE! We'd better ACK the irq immediately,
+	 * because timer handling can be slow.
+	 *
 	 * update_process_times() expects us to have done irq_enter().
 	 * Besides, if we don't timer interrupts ignore the global
 	 * interrupt lock, which is the WrongThing (tm) to do.
 	 */
-	irq_enter();
-	exit_idle();
+	entering_ack_irq();
+	trace_local_timer_entry(LOCAL_TIMER_VECTOR);
 	local_apic_timer_interrupt();
-	irq_exit();
+	trace_local_timer_exit(LOCAL_TIMER_VECTOR);
+	exiting_irq();
 
 	set_irq_regs(old_regs);
 }
@@ -1907,12 +1926,10 @@ int __init APIC_init_uniprocessor(void)
 /*
  * This interrupt should _never_ happen with our APIC/SMP architecture
  */
-void smp_spurious_interrupt(struct pt_regs *regs)
+static inline void __smp_spurious_interrupt(void)
 {
 	u32 v;
 
-	irq_enter();
-	exit_idle();
 	/*
 	 * Check if this really is a spurious interrupt and ACK it
 	 * if it is a vectored one.  Just in case...
@@ -1927,13 +1944,28 @@ void smp_spurious_interrupt(struct pt_regs *regs)
 	/* see sw-dev-man vol 3, chapter 7.4.13.5 */
 	pr_info("spurious APIC interrupt on CPU#%d, "
 		"should never happen.\n", smp_processor_id());
-	irq_exit();
+}
+
+void smp_spurious_interrupt(struct pt_regs *regs)
+{
+	entering_irq();
+	__smp_spurious_interrupt();
+	exiting_irq();
+}
+
+void smp_trace_spurious_interrupt(struct pt_regs *regs)
+{
+	entering_irq();
+	trace_spurious_apic_entry(SPURIOUS_APIC_VECTOR);
+	__smp_spurious_interrupt();
+	trace_spurious_apic_exit(SPURIOUS_APIC_VECTOR);
+	exiting_irq();
 }
 
 /*
  * This interrupt should never happen with our APIC/SMP architecture
  */
-void smp_error_interrupt(struct pt_regs *regs)
+static inline void __smp_error_interrupt(struct pt_regs *regs)
 {
 	u32 v0, v1;
 	u32 i = 0;
@@ -1948,8 +1980,6 @@ void smp_error_interrupt(struct pt_regs *regs)
 		"Illegal register address",	/* APIC Error Bit 7 */
 	};
 
-	irq_enter();
-	exit_idle();
 	/* First tickle the hardware, only then report what went on. -- REW */
 	v0 = apic_read(APIC_ESR);
 	apic_write(APIC_ESR, 0);
@@ -1970,7 +2000,22 @@ void smp_error_interrupt(struct pt_regs *regs)
 
 	apic_printk(APIC_DEBUG, KERN_CONT "\n");
 
-	irq_exit();
+}
+
+void smp_error_interrupt(struct pt_regs *regs)
+{
+	entering_irq();
+	__smp_error_interrupt(regs);
+	exiting_irq();
+}
+
+void smp_trace_error_interrupt(struct pt_regs *regs)
+{
+	entering_irq();
+	trace_error_apic_entry(ERROR_APIC_VECTOR);
+	__smp_error_interrupt(regs);
+	trace_error_apic_exit(ERROR_APIC_VECTOR);
+	exiting_irq();
 }
 
 /**
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index a4a07c0acb1..548bd039784 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1072,8 +1072,8 @@ __setup("clearcpuid=", setup_disablecpuid);
 
 #ifdef CONFIG_X86_64
 struct desc_ptr idt_descr = { NR_VECTORS * 16 - 1, (unsigned long) idt_table };
-struct desc_ptr nmi_idt_descr = { NR_VECTORS * 16 - 1,
-				    (unsigned long) nmi_idt_table };
+struct desc_ptr debug_idt_descr = { NR_VECTORS * 16 - 1,
+				    (unsigned long) debug_idt_table };
 
 DEFINE_PER_CPU_FIRST(union irq_stack_union,
 		     irq_stack_union) __aligned(PAGE_SIZE);
@@ -1149,20 +1149,20 @@ int is_debug_stack(unsigned long addr)
 		 addr > (__get_cpu_var(debug_stack_addr) - DEBUG_STKSZ));
 }
 
-static DEFINE_PER_CPU(u32, debug_stack_use_ctr);
+DEFINE_PER_CPU(u32, debug_idt_ctr);
 
 void debug_stack_set_zero(void)
 {
-	this_cpu_inc(debug_stack_use_ctr);
-	load_idt((const struct desc_ptr *)&nmi_idt_descr);
+	this_cpu_inc(debug_idt_ctr);
+	load_current_idt();
 }
 
 void debug_stack_reset(void)
 {
-	if (WARN_ON(!this_cpu_read(debug_stack_use_ctr)))
+	if (WARN_ON(!this_cpu_read(debug_idt_ctr)))
 		return;
-	if (this_cpu_dec_return(debug_stack_use_ctr) == 0)
-		load_idt((const struct desc_ptr *)&idt_descr);
+	if (this_cpu_dec_return(debug_idt_ctr) == 0)
+		load_current_idt();
 }
 
 #else	/* CONFIG_X86_64 */
@@ -1258,7 +1258,7 @@ void __cpuinit cpu_init(void)
 	switch_to_new_gdt(cpu);
 	loadsegment(fs, 0);
 
-	load_idt((const struct desc_ptr *)&idt_descr);
+	load_current_idt();
 
 	memset(me->thread.tls_array, 0, GDT_ENTRY_TLS_ENTRIES * 8);
 	syscall_init();
@@ -1335,7 +1335,7 @@ void __cpuinit cpu_init(void)
 	if (cpu_has_vme || cpu_has_tsc || cpu_has_de)
 		clear_in_cr4(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);
 
-	load_idt(&idt_descr);
+	load_current_idt();
 	switch_to_new_gdt(cpu);
 
 	/*
diff --git a/arch/x86/kernel/cpu/mcheck/therm_throt.c b/arch/x86/kernel/cpu/mcheck/therm_throt.c
index 47a1870279a..2f3a7995e56 100644
--- a/arch/x86/kernel/cpu/mcheck/therm_throt.c
+++ b/arch/x86/kernel/cpu/mcheck/therm_throt.c
@@ -29,6 +29,7 @@
 #include <asm/idle.h>
 #include <asm/mce.h>
 #include <asm/msr.h>
+#include <asm/trace/irq_vectors.h>
 
 /* How long to wait between reporting thermal events */
 #define CHECK_INTERVAL		(300 * HZ)
@@ -378,15 +379,26 @@ static void unexpected_thermal_interrupt(void)
 
 static void (*smp_thermal_vector)(void) = unexpected_thermal_interrupt;
 
-asmlinkage void smp_thermal_interrupt(struct pt_regs *regs)
+static inline void __smp_thermal_interrupt(void)
 {
-	irq_enter();
-	exit_idle();
 	inc_irq_stat(irq_thermal_count);
 	smp_thermal_vector();
-	irq_exit();
-	/* Ack only at the end to avoid potential reentry */
-	ack_APIC_irq();
+}
+
+asmlinkage void smp_thermal_interrupt(struct pt_regs *regs)
+{
+	entering_irq();
+	__smp_thermal_interrupt();
+	exiting_ack_irq();
+}
+
+asmlinkage void smp_trace_thermal_interrupt(struct pt_regs *regs)
+{
+	entering_irq();
+	trace_thermal_apic_entry(THERMAL_APIC_VECTOR);
+	__smp_thermal_interrupt();
+	trace_thermal_apic_exit(THERMAL_APIC_VECTOR);
+	exiting_ack_irq();
 }
 
 /* Thermal monitoring depends on APIC, ACPI and clock modulation */
diff --git a/arch/x86/kernel/cpu/mcheck/threshold.c b/arch/x86/kernel/cpu/mcheck/threshold.c
index aa578cadb94..fe6b1c86645 100644
--- a/arch/x86/kernel/cpu/mcheck/threshold.c
+++ b/arch/x86/kernel/cpu/mcheck/threshold.c
@@ -8,6 +8,7 @@
 #include <asm/apic.h>
 #include <asm/idle.h>
 #include <asm/mce.h>
+#include <asm/trace/irq_vectors.h>
 
 static void default_threshold_interrupt(void)
 {
@@ -17,13 +18,24 @@ static void default_threshold_interrupt(void)
 
 void (*mce_threshold_vector)(void) = default_threshold_interrupt;
 
-asmlinkage void smp_threshold_interrupt(void)
+static inline void __smp_threshold_interrupt(void)
 {
-	irq_enter();
-	exit_idle();
 	inc_irq_stat(irq_threshold_count);
 	mce_threshold_vector();
-	irq_exit();
-	/* Ack only at the end to avoid potential reentry */
-	ack_APIC_irq();
+}
+
+asmlinkage void smp_threshold_interrupt(void)
+{
+	entering_irq();
+	__smp_threshold_interrupt();
+	exiting_ack_irq();
+}
+
+asmlinkage void smp_trace_threshold_interrupt(void)
+{
+	entering_irq();
+	trace_threshold_apic_entry(THRESHOLD_APIC_VECTOR);
+	__smp_threshold_interrupt();
+	trace_threshold_apic_exit(THRESHOLD_APIC_VECTOR);
+	exiting_ack_irq();
 }
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index 8f3e2dec1df..2cfbc3a3a2d 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -801,7 +801,17 @@ ENTRY(name)				\
 	CFI_ENDPROC;			\
 ENDPROC(name)
 
-#define BUILD_INTERRUPT(name, nr)	BUILD_INTERRUPT3(name, nr, smp_##name)
+
+#ifdef CONFIG_TRACING
+#define TRACE_BUILD_INTERRUPT(name, nr)		\
+	BUILD_INTERRUPT3(trace_##name, nr, smp_trace_##name)
+#else
+#define TRACE_BUILD_INTERRUPT(name, nr)
+#endif
+
+#define BUILD_INTERRUPT(name, nr) \
+	BUILD_INTERRUPT3(name, nr, smp_##name); \
+	TRACE_BUILD_INTERRUPT(name, nr)
 
 /* The include is where all of the SMP etc. interrupts come from */
 #include <asm/entry_arch.h>
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 5fe1fb2d149..1b69951a81e 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -1138,7 +1138,7 @@ END(common_interrupt)
 /*
  * APIC interrupts.
  */
-.macro apicinterrupt num sym do_sym
+.macro apicinterrupt3 num sym do_sym
 ENTRY(\sym)
 	INTR_FRAME
 	ASM_CLAC
@@ -1150,15 +1150,32 @@ ENTRY(\sym)
 END(\sym)
 .endm
 
+#ifdef CONFIG_TRACING
+#define trace(sym) trace_##sym
+#define smp_trace(sym) smp_trace_##sym
+
+.macro trace_apicinterrupt num sym
+apicinterrupt3 \num trace(\sym) smp_trace(\sym)
+.endm
+#else
+.macro trace_apicinterrupt num sym do_sym
+.endm
+#endif
+
+.macro apicinterrupt num sym do_sym
+apicinterrupt3 \num \sym \do_sym
+trace_apicinterrupt \num \sym
+.endm
+
 #ifdef CONFIG_SMP
-apicinterrupt IRQ_MOVE_CLEANUP_VECTOR \
+apicinterrupt3 IRQ_MOVE_CLEANUP_VECTOR \
 	irq_move_cleanup_interrupt smp_irq_move_cleanup_interrupt
-apicinterrupt REBOOT_VECTOR \
+apicinterrupt3 REBOOT_VECTOR \
 	reboot_interrupt smp_reboot_interrupt
 #endif
 
 #ifdef CONFIG_X86_UV
-apicinterrupt UV_BAU_MESSAGE \
+apicinterrupt3 UV_BAU_MESSAGE \
 	uv_bau_message_intr1 uv_bau_message_interrupt
 #endif
 apicinterrupt LOCAL_TIMER_VECTOR \
@@ -1167,14 +1184,19 @@ apicinterrupt X86_PLATFORM_IPI_VECTOR \
 	x86_platform_ipi smp_x86_platform_ipi
 
 #ifdef CONFIG_HAVE_KVM
-apicinterrupt POSTED_INTR_VECTOR \
+apicinterrupt3 POSTED_INTR_VECTOR \
 	kvm_posted_intr_ipi smp_kvm_posted_intr_ipi
 #endif
 
+#ifdef CONFIG_X86_MCE_THRESHOLD
 apicinterrupt THRESHOLD_APIC_VECTOR \
 	threshold_interrupt smp_threshold_interrupt
+#endif
+
+#ifdef CONFIG_X86_THERMAL_VECTOR
 apicinterrupt THERMAL_APIC_VECTOR \
 	thermal_interrupt smp_thermal_interrupt
+#endif
 
 #ifdef CONFIG_SMP
 apicinterrupt CALL_FUNCTION_SINGLE_VECTOR \
@@ -1451,13 +1473,13 @@ ENTRY(xen_failsafe_callback)
 	CFI_ENDPROC
 END(xen_failsafe_callback)
 
-apicinterrupt HYPERVISOR_CALLBACK_VECTOR \
+apicinterrupt3 HYPERVISOR_CALLBACK_VECTOR \
 	xen_hvm_callback_vector xen_evtchn_do_upcall
 
 #endif /* CONFIG_XEN */
 
 #if IS_ENABLED(CONFIG_HYPERV)
-apicinterrupt HYPERVISOR_CALLBACK_VECTOR \
+apicinterrupt3 HYPERVISOR_CALLBACK_VECTOR \
 	hyperv_callback_vector hyperv_vector_handler
 #endif /* CONFIG_HYPERV */
 
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 321d65ebaff..5e4d8a8a5c4 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -518,9 +518,15 @@ ENTRY(idt_table)
 	.skip IDT_ENTRIES * 16
 
 	.align L1_CACHE_BYTES
-ENTRY(nmi_idt_table)
+ENTRY(debug_idt_table)
 	.skip IDT_ENTRIES * 16
 
+#ifdef CONFIG_TRACING
+	.align L1_CACHE_BYTES
+ENTRY(trace_idt_table)
+	.skip IDT_ENTRIES * 16
+#endif
+
 	__PAGE_ALIGNED_BSS
 NEXT_PAGE(empty_zero_page)
 	.skip PAGE_SIZE
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index ac0631d8996..3a8185c042a 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -18,6 +18,9 @@
 #include <asm/mce.h>
 #include <asm/hw_irq.h>
 
+#define CREATE_TRACE_POINTS
+#include <asm/trace/irq_vectors.h>
+
 atomic_t irq_err_count;
 
 /* Function pointer for generic interrupt vector handling */
@@ -204,23 +207,21 @@ unsigned int __irq_entry do_IRQ(struct pt_regs *regs)
 /*
  * Handler for X86_PLATFORM_IPI_VECTOR.
  */
-void smp_x86_platform_ipi(struct pt_regs *regs)
+void __smp_x86_platform_ipi(void)
 {
-	struct pt_regs *old_regs = set_irq_regs(regs);
-
-	ack_APIC_irq();
-
-	irq_enter();
-
-	exit_idle();
-
 	inc_irq_stat(x86_platform_ipis);
 
 	if (x86_platform_ipi_callback)
 		x86_platform_ipi_callback();
+}
 
-	irq_exit();
+void smp_x86_platform_ipi(struct pt_regs *regs)
+{
+	struct pt_regs *old_regs = set_irq_regs(regs);
 
+	entering_ack_irq();
+	__smp_x86_platform_ipi();
+	exiting_irq();
 	set_irq_regs(old_regs);
 }
 
@@ -246,6 +247,18 @@ void smp_kvm_posted_intr_ipi(struct pt_regs *regs)
 }
 #endif
 
+void smp_trace_x86_platform_ipi(struct pt_regs *regs)
+{
+	struct pt_regs *old_regs = set_irq_regs(regs);
+
+	entering_ack_irq();
+	trace_x86_platform_ipi_entry(X86_PLATFORM_IPI_VECTOR);
+	__smp_x86_platform_ipi();
+	trace_x86_platform_ipi_exit(X86_PLATFORM_IPI_VECTOR);
+	exiting_irq();
+	set_irq_regs(old_regs);
+}
+
 EXPORT_SYMBOL_GPL(vector_used_by_percpu_irq);
 
 #ifdef CONFIG_HOTPLUG_CPU
diff --git a/arch/x86/kernel/irq_work.c b/arch/x86/kernel/irq_work.c
index ca8f703a1e7..636a55e4a13 100644
--- a/arch/x86/kernel/irq_work.c
+++ b/arch/x86/kernel/irq_work.c
@@ -8,14 +8,34 @@
 #include <linux/irq_work.h>
 #include <linux/hardirq.h>
 #include <asm/apic.h>
+#include <asm/trace/irq_vectors.h>
 
-void smp_irq_work_interrupt(struct pt_regs *regs)
+static inline void irq_work_entering_irq(void)
 {
 	irq_enter();
 	ack_APIC_irq();
+}
+
+static inline void __smp_irq_work_interrupt(void)
+{
 	inc_irq_stat(apic_irq_work_irqs);
 	irq_work_run();
-	irq_exit();
+}
+
+void smp_irq_work_interrupt(struct pt_regs *regs)
+{
+	irq_work_entering_irq();
+	__smp_irq_work_interrupt();
+	exiting_irq();
+}
+
+void smp_trace_irq_work_interrupt(struct pt_regs *regs)
+{
+	irq_work_entering_irq();
+	trace_irq_work_entry(IRQ_WORK_VECTOR);
+	__smp_irq_work_interrupt();
+	trace_irq_work_exit(IRQ_WORK_VECTOR);
+	exiting_irq();
 }
 
 void arch_irq_work_raise(void)
diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index 48d2b7ded42..f4fe0b8879e 100644
--- a/arch/x86/kernel/smp.c
+++ b/arch/x86/kernel/smp.c
@@ -30,6 +30,7 @@
 #include <asm/proto.h>
 #include <asm/apic.h>
 #include <asm/nmi.h>
+#include <asm/trace/irq_vectors.h>
 /*
  *	Some notes on x86 processor bugs affecting SMP operation:
  *
@@ -249,32 +250,80 @@ finish:
 /*
  * 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();
+}
+
+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)
+void smp_trace_reschedule_interrupt(struct pt_regs *regs)
+{
+	ack_APIC_irq();
+	trace_reschedule_entry(RESCHEDULE_VECTOR);
+	__smp_reschedule_interrupt();
+	trace_reschedule_exit(RESCHEDULE_VECTOR);
+	/*
+	 * KVM uses this interrupt to force a cpu out of guest mode
+	 */
+}
+
+static inline void call_function_entering_irq(void)
 {
 	ack_APIC_irq();
 	irq_enter();
+}
+
+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)
+void smp_call_function_interrupt(struct pt_regs *regs)
+{
+	call_function_entering_irq();
+	__smp_call_function_interrupt();
+	exiting_irq();
+}
+
+void smp_trace_call_function_interrupt(struct pt_regs *regs)
+{
+	call_function_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();
+}
+
+void smp_call_function_single_interrupt(struct pt_regs *regs)
+{
+	call_function_entering_irq();
+	__smp_call_function_single_interrupt();
+	exiting_irq();
+}
+
+void smp_trace_call_function_single_interrupt(struct pt_regs *regs)
+{
+	call_function_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)
diff --git a/arch/x86/kernel/tracepoint.c b/arch/x86/kernel/tracepoint.c
new file mode 100644
index 00000000000..4e584a8d6ed
--- /dev/null
+++ b/arch/x86/kernel/tracepoint.c
@@ -0,0 +1,61 @@
+/*
+ * Code for supporting irq vector tracepoints.
+ *
+ * Copyright (C) 2013 Seiji Aguchi <seiji.aguchi@hds.com>
+ *
+ */
+#include <asm/hw_irq.h>
+#include <asm/desc.h>
+#include <linux/atomic.h>
+
+atomic_t trace_idt_ctr = ATOMIC_INIT(0);
+struct desc_ptr trace_idt_descr = { NR_VECTORS * 16 - 1,
+				(unsigned long) trace_idt_table };
+
+#ifndef CONFIG_X86_64
+gate_desc trace_idt_table[NR_VECTORS] __page_aligned_data
+					= { { { { 0, 0 } } }, };
+#endif
+
+static int trace_irq_vector_refcount;
+static DEFINE_MUTEX(irq_vector_mutex);
+
+static void set_trace_idt_ctr(int val)
+{
+	atomic_set(&trace_idt_ctr, val);
+	/* Ensure the trace_idt_ctr is set before sending IPI */
+	wmb();
+}
+
+static void switch_idt(void *arg)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	load_current_idt();
+	local_irq_restore(flags);
+}
+
+void trace_irq_vector_regfunc(void)
+{
+	mutex_lock(&irq_vector_mutex);
+	if (!trace_irq_vector_refcount) {
+		set_trace_idt_ctr(1);
+		smp_call_function(switch_idt, NULL, 0);
+		switch_idt(NULL);
+	}
+	trace_irq_vector_refcount++;
+	mutex_unlock(&irq_vector_mutex);
+}
+
+void trace_irq_vector_unregfunc(void)
+{
+	mutex_lock(&irq_vector_mutex);
+	trace_irq_vector_refcount--;
+	if (!trace_irq_vector_refcount) {
+		set_trace_idt_ctr(0);
+		smp_call_function(switch_idt, NULL, 0);
+		switch_idt(NULL);
+	}
+	mutex_unlock(&irq_vector_mutex);
+}
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index ee3d8e51050..b0865e88d3c 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -788,7 +788,7 @@ void __init trap_init(void)
 	x86_init.irqs.trap_init();
 
 #ifdef CONFIG_X86_64
-	memcpy(&nmi_idt_table, &idt_table, IDT_ENTRIES * 16);
+	memcpy(&debug_idt_table, &idt_table, IDT_ENTRIES * 16);
 	set_nmi_gate(X86_TRAP_DB, &debug);
 	set_nmi_gate(X86_TRAP_BP, &int3);
 #endif