Messages in this thread Patch in this message |  | | From | "Aneesh Kumar K.V" <> | Subject | [PATCH] ftrace: Add debug_print trace to print data from kernel to userspace | Date | Sun, 16 Nov 2008 16:08:02 +0530 |
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The trace add a new interface dp_printk() which can be used to dump data from kernel to user space using ftrace framework.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
--- include/linux/debug_print.h | 12 +++++ kernel/trace/Kconfig | 7 +++ kernel/trace/Makefile | 1 + kernel/trace/trace_debugprint.c | 90 +++++++++++++++++++++++++++++++++++++++ 4 files changed, 110 insertions(+), 0 deletions(-)
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 <linux/marker.h> + +#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 9c89526..30eccc8 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -254,4 +254,11 @@ 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 1a8c925..86e5869 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -31,5 +31,6 @@ obj-$(CONFIG_MMIOTRACE) += trace_mmiotrace.o obj-$(CONFIG_BOOT_TRACER) += trace_boot.o obj-$(CONFIG_FUNCTION_RET_TRACER) += trace_functions_return.o obj-$(CONFIG_TRACE_BRANCH_PROFILING) += trace_branch.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..2c3ac3d --- /dev/null +++ b/kernel/trace/trace_debugprint.c @@ -0,0 +1,90 @@ +/* + * Copyright IBM Corporation, 2008 + * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> + * + * 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 <linux/module.h> +#include <linux/fs.h> +#include <linux/debugfs.h> +#include <linux/ftrace.h> + +#include "trace.h" + +static int __read_mostly dp_tracer_enabled; + +int do_dp_printk(const char *fmt, ...) +{ + int ret; + va_list args; + + if (!dp_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 dp_trace_start(struct trace_array *tr) +{ + dp_reset(tr); + dp_tracer_enabled = 1; +} + +static void dp_trace_stop(struct trace_array *tr) +{ + dp_tracer_enabled = 0; + /* Nothing to do! */ +} + +static void dp_trace_init(struct trace_array *tr) +{ + /* + * enable the trace during init if + * we have enabled flag already set + */ + if (tracing_is_enabled()) + dp_trace_start(tr); +} + +static void dp_trace_reset(struct trace_array *tr) +{ + if (dp_tracer_enabled) + dp_trace_stop(tr); +} + +struct tracer dp_trace __read_mostly = +{ + .name = "debug_print", + .init = dp_trace_init, + .reset = dp_trace_reset, + .start = dp_trace_start, + .stop = dp_trace_stop, +}; + +__init static int init_dp_trace(void) +{ + return register_tracer(&dp_trace); +} +device_initcall(init_dp_trace); -- tg: (bfb3409..) an/ftrace-dp-printk.patch (depends on: an/ftrace-dump-iterator.patch)
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