[PATCH 1/2] trace,x86: Add external_interrupts to the irq_vectors class

[PATCH 1/2] trace,x86: Add external_interrupts to the irq_vectors class

[Daniel Bristot de Oliveira]

Currently, the irq_vectors is showing the entry and exit events for
the interrupts of the architecture, but not for external interrupts.
This patch adds the tracepoints for external interrupts.

Example of output:
 <idle>-0     [000] d.h.   102.890935: external_interrupt_entry: vector=35
 <idle>-0     [000] d.h.   102.890960: external_interrupt_exit: vector=35

Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: linux-kernel@vger.kernel.org
Cc: x86@kernel.org
---
 arch/x86/include/asm/trace/irq_vectors.h | 6 ++++++
 arch/x86/kernel/irq.c                    | 2 ++
 2 files changed, 8 insertions(+)

diff --git a/arch/x86/include/asm/trace/irq_vectors.h b/arch/x86/include/asm/trace/irq_vectors.h
index 0af81b590a0c..bc9669df97c9 100644
--- a/arch/x86/include/asm/trace/irq_vectors.h
+++ b/arch/x86/include/asm/trace/irq_vectors.h
@@ -138,6 +138,12 @@ DEFINE_IRQ_VECTOR_EVENT(deferred_error_apic);
 DEFINE_IRQ_VECTOR_EVENT(thermal_apic);
 #endif
 
+/*
+ * external_interrupt - called when entering/exiting from regular device
+ * interrupt vector handler.
+ */
+DEFINE_IRQ_VECTOR_EVENT(external_interrupt);
+
 TRACE_EVENT(vector_config,
 
 	TP_PROTO(unsigned int irq, unsigned int vector,
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 59b5f2ea7c2f..715afe3a4f24 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -237,6 +237,7 @@ __visible unsigned int __irq_entry do_IRQ(struct pt_regs *regs)
 	unsigned vector = ~regs->orig_ax;
 
 	entering_irq();
+	trace_external_interrupt_entry(vector);
 
 	/* entering_irq() tells RCU that we're not quiescent.  Check it. */
 	RCU_LOCKDEP_WARN(!rcu_is_watching(), "IRQ failed to wake up RCU");
@@ -255,6 +256,7 @@ __visible unsigned int __irq_entry do_IRQ(struct pt_regs *regs)
 		}
 	}
 
+	trace_external_interrupt_exit(vector);
 	exiting_irq();
 
 	set_irq_regs(old_regs);
-- 
2.17.1

[PATCH 2/2] trace,x86: Add nmi to the irq_vectors class

[Daniel Bristot de Oliveira]

Currently, the irq_vector class of tracepoints does not include the NMI
entry. The NMI was in the first set of tracepoints for IRQs, but it was
dropped off because of the logic of switching IDT when enabling trace[1].
However, as the switching IDT logic was removed [2], it is possible to add
the NMI tracepoints back.

The tracepoints looks like:
 <idle>-0     [000] d.Z.   179.594315: nmi_entry: vector=2
 <idle>-0     [000] d.Z.   179.594396: nmi_exit: vector=2

[1] trace,x86: irq vector tracepoint support
    https://lwn.net/Articles/555465/
[2] commit 4b9a8dca0e58 ("x86/idt: Remove the tracing IDT completely")

Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: linux-kernel@vger.kernel.org
Cc: x86@kernel.org
---
 arch/x86/include/asm/trace/irq_vectors.h | 5 +++++
 arch/x86/kernel/nmi.c                    | 4 ++++
 2 files changed, 9 insertions(+)

diff --git a/arch/x86/include/asm/trace/irq_vectors.h b/arch/x86/include/asm/trace/irq_vectors.h
index bc9669df97c9..5b93e1a6b1fe 100644
--- a/arch/x86/include/asm/trace/irq_vectors.h
+++ b/arch/x86/include/asm/trace/irq_vectors.h
@@ -144,6 +144,11 @@ DEFINE_IRQ_VECTOR_EVENT(thermal_apic);
  */
 DEFINE_IRQ_VECTOR_EVENT(external_interrupt);
 
+/*
+ * nmi - called when entering/exiting from nmi vector handler.
+ */
+DEFINE_IRQ_VECTOR_EVENT(nmi);
+
 TRACE_EVENT(vector_config,
 
 	TP_PROTO(unsigned int irq, unsigned int vector,
diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index 18bc9b51ac9b..fa2d16b3af60 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -37,6 +37,8 @@
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/nmi.h>
+#undef CREATE_TRACE_POINTS
+#include <asm/trace/irq_vectors.h>
 
 struct nmi_desc {
 	raw_spinlock_t lock;
@@ -514,12 +516,14 @@ do_nmi(struct pt_regs *regs, long error_code)
 #endif
 
 	nmi_enter();
+	trace_nmi_entry(2);
 
 	inc_irq_stat(__nmi_count);
 
 	if (!ignore_nmis)
 		default_do_nmi(regs);
 
+	trace_nmi_exit(2);
 	nmi_exit();
 
 #ifdef CONFIG_X86_64
-- 
2.17.1

Re: [PATCH 2/2] trace,x86: Add nmi to the irq_vectors class

[kbuild test robot]

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Hi Daniel,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on tip/x86/core]
[also build test ERROR on v4.19-rc4 next-20180913]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Daniel-Bristot-de-Oliveira/trace-x86-Add-external_interrupts-to-the-irq_vectors-class/20180917-173538
config: i386-randconfig-x003-201837 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All errors (new ones prefixed by >>):

   arch/x86/kernel/nmi.c: In function 'do_nmi':
>> arch/x86/kernel/nmi.c:519:2: error: implicit declaration of function 'trace_nmi_entry'; did you mean 'ftrace_nmi_enter'? [-Werror=implicit-function-declaration]
     trace_nmi_entry(2);
     ^~~~~~~~~~~~~~~
     ftrace_nmi_enter
>> arch/x86/kernel/nmi.c:526:2: error: implicit declaration of function 'trace_nmi_exit'; did you mean 'ftrace_nmi_exit'? [-Werror=implicit-function-declaration]
     trace_nmi_exit(2);
     ^~~~~~~~~~~~~~
     ftrace_nmi_exit
   cc1: some warnings being treated as errors

vim +519 arch/x86/kernel/nmi.c

   517	
   518		nmi_enter();
 > 519		trace_nmi_entry(2);
   520	
   521		inc_irq_stat(__nmi_count);
   522	
   523		if (!ignore_nmis)
   524			default_do_nmi(regs);
   525	
 > 526		trace_nmi_exit(2);
   527		nmi_exit();
   528	

---
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Re: [PATCH 1/2] trace,x86: Add external_interrupts to the irq_vectors class

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 2744 bytes --]

Hi Daniel,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on tip/x86/core]
[also build test ERROR on v4.19-rc4 next-20180913]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Daniel-Bristot-de-Oliveira/trace-x86-Add-external_interrupts-to-the-irq_vectors-class/20180917-173538
config: i386-randconfig-x003-201837 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All errors (new ones prefixed by >>):

   arch/x86/kernel/irq.c: In function 'do_IRQ':
>> arch/x86/kernel/irq.c:240:2: error: implicit declaration of function 'trace_external_interrupt_entry'; did you mean 'thermal_interrupt'? [-Werror=implicit-function-declaration]
     trace_external_interrupt_entry(vector);
     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     thermal_interrupt
>> arch/x86/kernel/irq.c:259:2: error: implicit declaration of function 'trace_external_interrupt_exit'; did you mean 'thermal_interrupt'? [-Werror=implicit-function-declaration]
     trace_external_interrupt_exit(vector);
     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     thermal_interrupt
   cc1: some warnings being treated as errors

vim +240 arch/x86/kernel/irq.c

   225	
   226	
   227	/*
   228	 * do_IRQ handles all normal device IRQ's (the special
   229	 * SMP cross-CPU interrupts have their own specific
   230	 * handlers).
   231	 */
   232	__visible unsigned int __irq_entry do_IRQ(struct pt_regs *regs)
   233	{
   234		struct pt_regs *old_regs = set_irq_regs(regs);
   235		struct irq_desc * desc;
   236		/* high bit used in ret_from_ code  */
   237		unsigned vector = ~regs->orig_ax;
   238	
   239		entering_irq();
 > 240		trace_external_interrupt_entry(vector);
   241	
   242		/* entering_irq() tells RCU that we're not quiescent.  Check it. */
   243		RCU_LOCKDEP_WARN(!rcu_is_watching(), "IRQ failed to wake up RCU");
   244	
   245		desc = __this_cpu_read(vector_irq[vector]);
   246	
   247		if (!handle_irq(desc, regs)) {
   248			ack_APIC_irq();
   249	
   250			if (desc != VECTOR_RETRIGGERED) {
   251				pr_emerg_ratelimited("%s: %d.%d No irq handler for vector\n",
   252						     __func__, smp_processor_id(),
   253						     vector);
   254			} else {
   255				__this_cpu_write(vector_irq[vector], VECTOR_UNUSED);
   256			}
   257		}
   258	
 > 259		trace_external_interrupt_exit(vector);
   260		exiting_irq();
   261	
   262		set_irq_regs(old_regs);
   263		return 1;
   264	}
   265	

---
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