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Message-Id: <1226659566-28168-3-git-send-email-aneesh.kumar@linux.vnet.ibm.com>
Date: Fri, 14 Nov 2008 16:16:06 +0530
From: "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
To: rostedt@...dmis.org, mingo@...e.hu, akpm@...ux-foundation.org
Cc: linux-kernel@...r.kernel.org,
"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
Subject: [PATCH 3/3] ftrace: Add debug_dump trace to dump binary data from kernel to userspace
The trace add a new interface debug_dump() which can be used
to dump binary data using ftrace framework. Use the bin mode
of iterator by 'echo bin > iter_ctrl' to read the value in
userspace
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@...ux.vnet.ibm.com>
---
include/linux/debug_dump.h | 10 +++
kernel/trace/Kconfig | 6 ++
kernel/trace/Makefile | 1 +
kernel/trace/trace.c | 4 +
kernel/trace/trace.h | 3 +
kernel/trace/trace_debugdump.c | 172 ++++++++++++++++++++++++++++++++++++++++
6 files changed, 196 insertions(+), 0 deletions(-)
create mode 100644 include/linux/debug_dump.h
create mode 100644 kernel/trace/trace_debugdump.c
diff --git a/include/linux/debug_dump.h b/include/linux/debug_dump.h
new file mode 100644
index 0000000..2c1836d
--- /dev/null
+++ b/include/linux/debug_dump.h
@@ -0,0 +1,10 @@
+#ifndef _LINUX_DEBUGDUMP_H
+#define _LINUX_DEBUGDUMP_H
+#include <linux/marker.h>
+
+#ifdef CONFIG_DEBUG_DUMP
+extern int debug_dump(void *p, int len);
+#else
+#define debug_dump(p, len)
+#endif
+#endif /* _LINUX_DEBUGDUMP_H */
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 9b832e0..ddde659 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -202,4 +202,10 @@ config DEBUG_PRINT
help
This tracer can be used for printk style debugging.
+config DEBUG_DUMP
+ bool "Trace based dump support"
+ depends on DEBUG_KERNEL
+ select TRACING
+ help
+ This tracer can be used to dump binary data from kernel
endmenu
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index afbf059..afd1be7 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -25,5 +25,6 @@ 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
+obj-$(CONFIG_DEBUG_DUMP) += trace_debugdump.o
libftrace-y := ftrace.o
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index fb32a5c..b62eebe 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -156,6 +156,10 @@ static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
/* trace_flags holds iter_ctrl options */
unsigned long trace_flags = TRACE_ITER_PRINT_PARENT;
+struct trace_array *trace_get_global_trace(void)
+{
+ return &global_trace;
+}
/**
* trace_wake_up - wake up tasks waiting for trace input
*
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 8465ad0..345bea2 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -22,6 +22,7 @@ enum trace_type {
TRACE_MMIO_RW,
TRACE_MMIO_MAP,
TRACE_BOOT,
+ TRACE_BIN_DUMP,
__TRACE_LAST_TYPE
};
@@ -219,6 +220,7 @@ extern void __ftrace_bad_type(void);
IF_ASSIGN(var, ent, struct trace_mmiotrace_map, \
TRACE_MMIO_MAP); \
IF_ASSIGN(var, ent, struct trace_boot, TRACE_BOOT); \
+ IF_ASSIGN(var, ent, struct dump_entry, TRACE_BIN_DUMP); \
__ftrace_bad_type(); \
} while (0)
@@ -393,6 +395,7 @@ extern ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
size_t cnt);
extern long ns2usecs(cycle_t nsec);
extern int trace_vprintk(unsigned long ip, const char *fmt, va_list args);
+extern struct trace_array *trace_get_global_trace(void);
extern unsigned long trace_flags;
diff --git a/kernel/trace/trace_debugdump.c b/kernel/trace/trace_debugdump.c
new file mode 100644
index 0000000..8c7c56f
--- /dev/null
+++ b/kernel/trace/trace_debugdump.c
@@ -0,0 +1,172 @@
+/*
+ * Copyright IBM Corporation, 2008
+ * Author Aneesh Kumar K.V <aneesh.kumar@...ux.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"
+
+struct dump_entry {
+ struct trace_entry ent;
+ int len;
+ char buf[];
+};
+
+static struct trace_array *ctx_trace;
+static int __read_mostly tracer_enabled;
+
+int debug_dump(void *bin_data, int len)
+{
+ struct ring_buffer_event *event;
+ struct trace_array *tr;
+ struct trace_array_cpu *data;
+ struct dump_entry *entry;
+ unsigned long flags, irq_flags;
+ int cpu, size, pc;
+
+ if (!tracer_enabled)
+ return 0;
+ tr = trace_get_global_trace();
+ pc = preempt_count();
+ preempt_disable_notrace();
+ cpu = raw_smp_processor_id();
+ data = tr->data[cpu];
+
+ local_irq_save(flags);
+ size = sizeof(*entry) + len;
+ event = ring_buffer_lock_reserve(tr->buffer, size, &irq_flags);
+ if (!event)
+ goto out;
+ entry = ring_buffer_event_data(event);
+ tracing_generic_entry_update(&entry->ent, flags, pc);
+ entry->ent.type = TRACE_BIN_DUMP;
+ entry->len = len;
+
+ memcpy(&entry->buf, bin_data, len);
+ ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
+
+out:
+ local_irq_restore(flags);
+ preempt_enable_notrace();
+
+ return len;
+}
+EXPORT_SYMBOL_GPL(debug_dump);
+
+static void dd_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_dd_trace(struct trace_array *tr)
+{
+ dd_reset(tr);
+ tracer_enabled = 1;
+}
+
+static void stop_dd_trace(struct trace_array *tr)
+{
+ tracer_enabled = 0;
+ /* Nothing to do! */
+}
+
+static void dd_trace_init(struct trace_array *tr)
+{
+ ctx_trace = tr;
+
+ if (tr->ctrl)
+ start_dd_trace(tr);
+}
+
+static void dd_trace_reset(struct trace_array *tr)
+{
+ if (tr->ctrl)
+ stop_dd_trace(tr);
+}
+
+static void dd_trace_ctrl_update(struct trace_array *tr)
+{
+ /* When starting a new trace, reset the buffers */
+ if (tr->ctrl)
+ start_dd_trace(tr);
+ else
+ stop_dd_trace(tr);
+}
+
+#ifdef CONFIG_NOP_TRACER
+int
+trace_selftest_startup_dd(struct tracer *trace, struct trace_array *tr)
+{
+ /* What could possibly go wrong? */
+ return 0;
+}
+#endif
+
+static int
+trace_seq_putmem(struct trace_seq *s, void *mem, size_t len)
+{
+ if (len > ((PAGE_SIZE - 1) - s->len))
+ return 0;
+
+ memcpy(s->buffer + s->len, mem, len);
+ s->len += len;
+
+ return len;
+}
+
+static enum print_line_t debug_dump_entry(struct trace_iterator *iter)
+{
+ struct trace_seq *s = &iter->seq;
+ struct trace_entry *entry;
+
+ entry = iter->ent;
+ switch (entry->type) {
+ case TRACE_BIN_DUMP: {
+ struct dump_entry *field;
+ trace_assign_type(field, entry);
+ trace_seq_putmem(s, field->buf, field->len);
+ break;
+ }
+ default:
+ printk(KERN_INFO "Unsupported type in debug_dump\n");
+ return TRACE_TYPE_UNHANDLED;
+ }
+
+ return TRACE_TYPE_HANDLED;
+}
+
+struct tracer dd_trace __read_mostly =
+{
+ .name = "debug_dump",
+ .init = dd_trace_init,
+ .reset = dd_trace_reset,
+ .ctrl_update = dd_trace_ctrl_update,
+#ifdef CONFIG_FTRACE_SELFTEST
+ .selftest = trace_selftest_startup_dd,
+#endif
+ .print_line = debug_dump_entry,
+};
+
+__init static int init_dd_trace(void)
+{
+ return register_tracer(&dd_trace);
+}
+device_initcall(init_dd_trace);
--
1.6.0.4.608.ga9645
--
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