From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756630AbZD1T20 (ORCPT ); Tue, 28 Apr 2009 15:28:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753955AbZD1T1s (ORCPT ); Tue, 28 Apr 2009 15:27:48 -0400 Received: from relay.pcl-ipout01.plus.net ([212.159.7.99]:22001 "EHLO relay.pcl-ipout01.plus.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754989AbZD1T1r (ORCPT ); Tue, 28 Apr 2009 15:27:47 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: ApoEAL/z9knUnw4R/2dsb2JhbAC/J5Agg3MF From: Stuart Bennett To: Ingo Molnar , Steven Rostedt Cc: Pekka Paalanen , linux-kernel@vger.kernel.org, Stuart Bennett Subject: [PATCH] x86 mmiotrace: only register for die notifier when tracer active Date: Tue, 28 Apr 2009 20:17:51 +0100 Message-Id: <1240946271-7083-5-git-send-email-stuart@freedesktop.org> X-Mailer: git-send-email 1.5.4.4 In-Reply-To: <1240946271-7083-4-git-send-email-stuart@freedesktop.org> References: <1240946271-7083-1-git-send-email-stuart@freedesktop.org> <1240946271-7083-2-git-send-email-stuart@freedesktop.org> <1240946271-7083-3-git-send-email-stuart@freedesktop.org> <1240946271-7083-4-git-send-email-stuart@freedesktop.org> X-Plusnet-Relay: 998feba60ec0d1eb7d78f088a84f5440 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Follow up to afcfe024aebd74b0984a41af9a34e009cf5badaf in Linus' tree ("x86: mmiotrace: quieten spurious warning message") Signed-off-by: Stuart Bennett Acked-by: Pekka Paalanen --- arch/x86/mm/kmmio.c | 21 ++++++++++++++++++--- arch/x86/mm/mmio-mod.c | 2 ++ include/linux/mmiotrace.h | 2 ++ 3 files changed, 22 insertions(+), 3 deletions(-) diff --git a/arch/x86/mm/kmmio.c b/arch/x86/mm/kmmio.c index 422f49e..bdbbf0d 100644 --- a/arch/x86/mm/kmmio.c +++ b/arch/x86/mm/kmmio.c @@ -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); 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()); goto out; } @@ -545,11 +550,21 @@ static struct notifier_block nb_die = { .notifier_call = kmmio_die_notifier }; -static int __init init_kmmio(void) +int kmmio_init(void) { int i; for (i = 0; i < KMMIO_PAGE_TABLE_SIZE; i++) INIT_LIST_HEAD(&kmmio_page_table[i]); 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"); +} diff --git a/arch/x86/mm/mmio-mod.c b/arch/x86/mm/mmio-mod.c index c9342ed..132772a 100644 --- a/arch/x86/mm/mmio-mod.c +++ b/arch/x86/mm/mmio-mod.c @@ -451,6 +451,7 @@ void enable_mmiotrace(void) if (nommiotrace) pr_info(NAME "MMIO tracing disabled.\n"); + kmmio_init(); enter_uniprocessor(); spin_lock_irq(&trace_lock); atomic_inc(&mmiotrace_enabled); @@ -473,6 +474,7 @@ void disable_mmiotrace(void) clear_trace_list(); /* guarantees: no more kmmio callbacks */ leave_uniprocessor(); + kmmio_cleanup(); pr_info(NAME "disabled.\n"); out: mutex_unlock(&mmiotrace_mutex); diff --git a/include/linux/mmiotrace.h b/include/linux/mmiotrace.h index 3d1b7bd..97491f7 100644 --- a/include/linux/mmiotrace.h +++ b/include/linux/mmiotrace.h @@ -30,6 +30,8 @@ extern unsigned int kmmio_count; extern int register_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 /* kmmio is active by some kmmio_probes? */ -- 1.5.4.4