Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932643AbZAPK6v (ORCPT ); Fri, 16 Jan 2009 05:58:51 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757254AbZAPK6g (ORCPT ); Fri, 16 Jan 2009 05:58:36 -0500 Received: from mga11.intel.com ([192.55.52.93]:5903 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757043AbZAPK6e (ORCPT ); Fri, 16 Jan 2009 05:58:34 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.37,276,1231142400"; d="scan'208";a="657637382" Date: Fri, 16 Jan 2009 11:58:29 +0100 From: Markus Metzger To: linux-kernel@vger.kernel.org, mingo@elte.hu, tglx@linutronix.de, hpa@zytor.com Cc: markus.t.metzger@intel.com, markus.t.metzger@gmail.com, srostedt@redhat.com Subject: [patch 3/5] x86, ftrace, hw-branch-tracer: dump on oops Message-ID: <20090116115829.A30245@sedona.ch.intel.com> Mime-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.2.5i Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5547 Lines: 190 Dump the branch trace on an oops (based on ftrace_dump_on_oops). Signed-off-by: Markus Metzger --- Index: ftrace/arch/x86/kernel/dumpstack.c =================================================================== --- ftrace.orig/arch/x86/kernel/dumpstack.c 2009-01-14 15:21:46.000000000 +0100 +++ ftrace/arch/x86/kernel/dumpstack.c 2009-01-14 15:26:11.000000000 +0100 @@ -14,6 +14,7 @@ #include #include #include +#include #include @@ -195,6 +196,11 @@ int cpu; unsigned long flags; + /* notify the hw-branch tracer so it may disable tracing and + add the last trace to the trace buffer - + the earlier this happens, the more useful the trace. */ + trace_hw_branch_oops(); + oops_enter(); /* racy, but better than risking deadlock. */ Index: ftrace/kernel/trace/trace.h =================================================================== --- ftrace.orig/kernel/trace/trace.h 2009-01-14 15:21:46.000000000 +0100 +++ ftrace/kernel/trace/trace.h 2009-01-14 15:26:11.000000000 +0100 @@ -415,7 +415,6 @@ void trace_graph_return(struct ftrace_graph_ret *trace); int trace_graph_entry(struct ftrace_graph_ent *trace); -void trace_hw_branch(struct trace_array *tr, u64 from, u64 to); void tracing_start_cmdline_record(void); void tracing_stop_cmdline_record(void); Index: ftrace/kernel/trace/trace_hw_branches.c =================================================================== --- ftrace.orig/kernel/trace/trace_hw_branches.c 2009-01-14 15:26:07.000000000 +0100 +++ ftrace/kernel/trace/trace_hw_branches.c 2009-01-14 15:26:11.000000000 +0100 @@ -39,6 +39,7 @@ #define this_buffer per_cpu(buffer, smp_processor_id()) static int __read_mostly trace_hw_branches_enabled; +static struct trace_array *hw_branch_trace __read_mostly; /* @@ -127,6 +128,8 @@ static int bts_trace_init(struct trace_array *tr) { + hw_branch_trace = tr; + register_hotcpu_notifier(&bts_hotcpu_notifier); tracing_reset_online_cpus(tr); bts_trace_start(tr); @@ -138,6 +141,8 @@ { bts_trace_stop(tr); unregister_hotcpu_notifier(&bts_hotcpu_notifier); + + hw_branch_trace = NULL; } static void bts_trace_print_header(struct seq_file *m) @@ -166,8 +171,9 @@ return TRACE_TYPE_UNHANDLED; } -void trace_hw_branch(struct trace_array *tr, u64 from, u64 to) +void trace_hw_branch(u64 from, u64 to) { + struct trace_array *tr = hw_branch_trace; struct ring_buffer_event *event; struct hw_branch_entry *entry; unsigned long irq1, irq2; @@ -200,8 +206,7 @@ local_irq_restore(irq1); } -static void trace_bts_at(struct trace_array *tr, - const struct bts_trace *trace, void *at) +static void trace_bts_at(const struct bts_trace *trace, void *at) { struct bts_struct bts; int err = 0; @@ -216,7 +221,7 @@ switch (bts.qualifier) { case BTS_BRANCH: - trace_hw_branch(tr, bts.variant.lbr.from, bts.variant.lbr.to); + trace_hw_branch(bts.variant.lbr.from, bts.variant.lbr.to); break; } } @@ -232,12 +237,15 @@ const struct bts_trace *trace; unsigned char *at; - if (!this_tracer) + if (unlikely(!tr)) return; if (unlikely(atomic_read(&tr->data[raw_smp_processor_id()]->disabled))) return; + if (unlikely(!this_tracer)) + return; + ds_suspend_bts(this_tracer); trace = ds_read_bts(this_tracer); if (!trace) @@ -245,11 +253,11 @@ for (at = trace->ds.top; (void *)at < trace->ds.end; at += trace->ds.size) - trace_bts_at(tr, trace, at); + trace_bts_at(trace, at); for (at = trace->ds.begin; (void *)at < trace->ds.top; at += trace->ds.size) - trace_bts_at(tr, trace, at); + trace_bts_at(trace, at); out: ds_resume_bts(this_tracer); @@ -264,6 +272,15 @@ mutex_unlock(&bts_tracer_mutex); } +void trace_hw_branch_oops(void) +{ + mutex_lock(&bts_tracer_mutex); + + trace_bts_cpu(hw_branch_trace); + + mutex_unlock(&bts_tracer_mutex); +} + struct tracer bts_tracer __read_mostly = { .name = "hw-branch-tracer", Index: ftrace/include/linux/ftrace.h =================================================================== --- ftrace.orig/include/linux/ftrace.h 2009-01-14 15:21:46.000000000 +0100 +++ ftrace/include/linux/ftrace.h 2009-01-14 15:26:11.000000000 +0100 @@ -492,4 +492,17 @@ #endif /* CONFIG_TRACING */ + +#ifdef CONFIG_HW_BRANCH_TRACER + +void trace_hw_branch(u64 from, u64 to); +void trace_hw_branch_oops(void); + +#else /* CONFIG_HW_BRANCH_TRACER */ + +static inline void trace_hw_branch(u64 from, u64 to) {} +static inline void trace_hw_branch_oops(void) {} + +#endif /* CONFIG_HW_BRANCH_TRACER */ + #endif /* _LINUX_FTRACE_H */ --------------------------------------------------------------------- Intel GmbH Dornacher Strasse 1 85622 Feldkirchen/Muenchen Germany Sitz der Gesellschaft: Feldkirchen bei Muenchen Geschaeftsfuehrer: Douglas Lusk, Peter Gleissner, Hannes Schwaderer Registergericht: Muenchen HRB 47456 Ust.-IdNr. 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