Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754159AbYKNKq4 (ORCPT ); Fri, 14 Nov 2008 05:46:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751963AbYKNKqf (ORCPT ); Fri, 14 Nov 2008 05:46:35 -0500 Received: from e28smtp03.in.ibm.com ([59.145.155.3]:48954 "EHLO e28smtp03.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751447AbYKNKqd (ORCPT ); Fri, 14 Nov 2008 05:46:33 -0500 From: "Aneesh Kumar K.V" To: rostedt@goodmis.org, mingo@elte.hu, akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, "Aneesh Kumar K.V" Subject: [PATCH 2/3] ftrace: Add debug_print trace to print data from kernel to userspace Date: Fri, 14 Nov 2008 16:16:05 +0530 Message-Id: <1226659566-28168-2-git-send-email-aneesh.kumar@linux.vnet.ibm.com> X-Mailer: git-send-email 1.6.0.4.608.ga9645 In-Reply-To: <1226659566-28168-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> References: <1226659566-28168-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5218 Lines: 206 The trace add a new interface debug_print() which can be used to dump data from kernel to user space using ftrace framework. Signed-off-by: Aneesh Kumar K.V --- include/linux/debug_print.h | 12 ++++ kernel/trace/Kconfig | 7 ++ kernel/trace/Makefile | 1 + kernel/trace/trace_debugprint.c | 134 +++++++++++++++++++++++++++++++++++++++ 4 files changed, 154 insertions(+), 0 deletions(-) create mode 100644 include/linux/debug_print.h create mode 100644 kernel/trace/trace_debugprint.c diff --git a/include/linux/debug_print.h b/include/linux/debug_print.h new file mode 100644 index 0000000..db4397b --- /dev/null +++ b/include/linux/debug_print.h @@ -0,0 +1,12 @@ +#ifndef _LINUX_DEBUGPRINT_H +#define _LINUX_DEBUGPRINT_H +#include + +#ifdef CONFIG_DEBUG_PRINT +extern int do_dp_printk(const char *fmt, ...); +#define dp_printk(fmt, arg...) \ + do_dp_printk(fmt, ##arg) +#else +#define dp_printk(fmt, arg...) +#endif +#endif /* _LINUX_DEBUGPRINT_H */ diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index b58f43b..9b832e0 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -195,4 +195,11 @@ config FTRACE_STARTUP_TEST functioning properly. It will do tests on all the configured tracers of ftrace. +config DEBUG_PRINT + bool "Trace based printk support" + depends on DEBUG_KERNEL + select TRACING + help + This tracer can be used for printk style debugging. + endmenu diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index c8228b1..afbf059 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -24,5 +24,6 @@ obj-$(CONFIG_NOP_TRACER) += trace_nop.o obj-$(CONFIG_STACK_TRACER) += trace_stack.o obj-$(CONFIG_MMIOTRACE) += trace_mmiotrace.o obj-$(CONFIG_BOOT_TRACER) += trace_boot.o +obj-$(CONFIG_DEBUG_PRINT) += trace_debugprint.o libftrace-y := ftrace.o diff --git a/kernel/trace/trace_debugprint.c b/kernel/trace/trace_debugprint.c new file mode 100644 index 0000000..feb38d8 --- /dev/null +++ b/kernel/trace/trace_debugprint.c @@ -0,0 +1,134 @@ +/* + * Copyright IBM Corporation, 2008 + * Author Aneesh Kumar K.V + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of version 2.1 of the GNU Lesser General Public License + * as published by the Free Software Foundation. + * + * This program is distributed in the hope that it would be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + * + */ + +#include +#include +#include +#include + +#include "trace.h" + +static struct trace_array *ctx_trace; +static int __read_mostly tracer_enabled; + +int do_dp_printk(const char *fmt, ...) +{ + int ret; + va_list args; + + if (!tracer_enabled) + return 0; + + va_start(args, fmt); + ret = trace_vprintk(0, fmt, args); + va_end(args); + return ret; +} +EXPORT_SYMBOL(do_dp_printk); + +static void dp_reset(struct trace_array *tr) +{ + int cpu; + + tr->time_start = ftrace_now(tr->cpu); + + for_each_online_cpu(cpu) + tracing_reset(tr, cpu); +} + +static void start_dp_trace(struct trace_array *tr) +{ + dp_reset(tr); + tracer_enabled = 1; +} + +static void stop_dp_trace(struct trace_array *tr) +{ + tracer_enabled = 0; + /* Nothing to do! */ +} + +static void dp_trace_init(struct trace_array *tr) +{ + ctx_trace = tr; + + if (tr->ctrl) + start_dp_trace(tr); +} + +static void dp_trace_reset(struct trace_array *tr) +{ + if (tr->ctrl) + stop_dp_trace(tr); +} + +static void dp_trace_ctrl_update(struct trace_array *tr) +{ + /* When starting a new trace, reset the buffers */ + if (tr->ctrl) + start_dp_trace(tr); + else + stop_dp_trace(tr); +} + +#ifdef CONFIG_NOP_TRACER +int +trace_selftest_startup_dp(struct tracer *trace, struct trace_array *tr) +{ + /* What could possibly go wrong? */ + return 0; +} +#endif + +static enum print_line_t debug_print_line(struct trace_iterator *iter) +{ + struct trace_seq *s = &iter->seq; + struct trace_entry *entry; + + entry = iter->ent; + switch (entry->type) { + case TRACE_PRINT: { + struct print_entry *field; + trace_assign_type(field, entry); + + trace_seq_printf(s, "%s", field->buf); + if (entry->flags & TRACE_FLAG_CONT) + trace_seq_print_cont(s, iter); + break; + } + default: + printk(KERN_INFO "Unsupported type in debug_print\n"); + return TRACE_TYPE_UNHANDLED; + } + + return TRACE_TYPE_HANDLED; +} + +struct tracer dp_trace __read_mostly = +{ + .name = "debug_print", + .init = dp_trace_init, + .reset = dp_trace_reset, + .ctrl_update = dp_trace_ctrl_update, +#ifdef CONFIG_FTRACE_SELFTEST + .selftest = trace_selftest_startup_dp, +#endif + .print_line = debug_print_line, +}; + +__init static int init_dp_trace(void) +{ + return register_tracer(&dp_trace); +} +device_initcall(init_dp_trace); -- 1.6.0.4.608.ga9645 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/