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Commit 0f9a623d authored by Stuart Bennett's avatar Stuart Bennett Committed by Ingo Molnar
Browse files

tracing: x86, mmiotrace: only register for die notifier when tracer active 



Follow up to afcfe024 in Linus' tree
("x86: mmiotrace: quieten spurious warning message")

Signed-off-by: default avatarStuart Bennett <stuart@freedesktop.org>
Acked-by: default avatarPekka Paalanen <pq@iki.fi>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1240946271-7083-5-git-send-email-stuart@freedesktop.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 46e91d00

arch/x86/mm/kmmio.c

+22 −5
Original line number Original line Diff line number Diff line
@@ -311,7 +311,12 @@ static int post_kmmio_handler(unsigned long condition, struct pt_regs *regs) 
	struct kmmio_context *ctx = &get_cpu_var(kmmio_ctx);

	struct kmmio_context *ctx = &get_cpu_var(kmmio_ctx);





	if (!ctx->active) {

	if (!ctx->active) {

		pr_debug("kmmio: spurious debug trap on CPU %d.\n",

		/*

		 * debug traps without an active context are due to either

		 * something external causing them (f.e. using a debugger while

		 * mmio tracing enabled), or erroneous behaviour

		 */

		pr_warning("kmmio: unexpected debug trap on CPU %d.\n",

							smp_processor_id());

							smp_processor_id());

		goto out;

		goto out;

	}

	}
@@ -529,8 +534,8 @@ void unregister_kmmio_probe(struct kmmio_probe *p) 
}

}

EXPORT_SYMBOL(unregister_kmmio_probe);

EXPORT_SYMBOL(unregister_kmmio_probe);





static int kmmio_die_notifier(struct notifier_block *nb, unsigned long val,

static int

								void *args)

kmmio_die_notifier(struct notifier_block *nb, unsigned long val, void *args)

{

{

	struct die_args *arg = args;

	struct die_args *arg = args;
@@ -545,11 +550,23 @@ static struct notifier_block nb_die = { 
	.notifier_call = kmmio_die_notifier

	.notifier_call = kmmio_die_notifier

};

};





static int __init init_kmmio(void)

int kmmio_init(void)

{

{

	int i;

	int i;



	for (i = 0; i < KMMIO_PAGE_TABLE_SIZE; i++)

	for (i = 0; i < KMMIO_PAGE_TABLE_SIZE; i++)

		INIT_LIST_HEAD(&kmmio_page_table[i]);

		INIT_LIST_HEAD(&kmmio_page_table[i]);



	return register_die_notifier(&nb_die);

	return register_die_notifier(&nb_die);

}

}

fs_initcall(init_kmmio); /* should be before device_initcall() */
 


void kmmio_cleanup(void)

{

	int i;



	unregister_die_notifier(&nb_die);

	for (i = 0; i < KMMIO_PAGE_TABLE_SIZE; i++) {

		WARN_ONCE(!list_empty(&kmmio_page_table[i]),

			KERN_ERR "kmmio_page_table not empty at cleanup, any further tracing will leak memory.\n");

	}

}

arch/x86/mm/mmio-mod.c

+2 −0
Original line number Original line Diff line number Diff line
@@ -451,6 +451,7 @@ void enable_mmiotrace(void) 




	if (nommiotrace)

	if (nommiotrace)

		pr_info(NAME "MMIO tracing disabled.\n");

		pr_info(NAME "MMIO tracing disabled.\n");

	kmmio_init();

	enter_uniprocessor();

	enter_uniprocessor();

	spin_lock_irq(&trace_lock);

	spin_lock_irq(&trace_lock);

	atomic_inc(&mmiotrace_enabled);

	atomic_inc(&mmiotrace_enabled);
@@ -473,6 +474,7 @@ void disable_mmiotrace(void) 




	clear_trace_list(); /* guarantees: no more kmmio callbacks */

	clear_trace_list(); /* guarantees: no more kmmio callbacks */

	leave_uniprocessor();

	leave_uniprocessor();

	kmmio_cleanup();

	pr_info(NAME "disabled.\n");

	pr_info(NAME "disabled.\n");

out:

out:

	mutex_unlock(&mmiotrace_mutex);

	mutex_unlock(&mmiotrace_mutex);

include/linux/mmiotrace.h

+2 −0
Original line number Original line Diff line number Diff line
@@ -30,6 +30,8 @@ extern unsigned int kmmio_count; 




extern int register_kmmio_probe(struct kmmio_probe *p);

extern int register_kmmio_probe(struct kmmio_probe *p);

extern void unregister_kmmio_probe(struct kmmio_probe *p);

extern void unregister_kmmio_probe(struct kmmio_probe *p);

extern int kmmio_init(void);

extern void kmmio_cleanup(void);





#ifdef CONFIG_MMIOTRACE

#ifdef CONFIG_MMIOTRACE

/* kmmio is active by some kmmio_probes? */

/* kmmio is active by some kmmio_probes? */