Commit-ID: 1ba28e02a18cbdbea123836f6c98efb09cbf59ec
Gitweb: http://git.kernel.org/tip/1ba28e02a18cbdbea123836f6c98efb09cbf59ec
Author: "Lai Jiangshan" <laijs@xxxxxxxxxxxxxx>
AuthorDate: Fri, 6 Mar 2009 17:21:48 +0100
Commit: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Fri, 6 Mar 2009 17:59:11 +0100
tracing: add trace_bprintk()
Impact: add a generic printk() for tracing, like trace_printk()
trace_bprintk() uses the infrastructure to record events on ring_buffer.
[ fweisbec@xxxxxxxxx: ported to latest -tip, made it work if
!CONFIG_MODULES, never free the format strings from modules
because we can't keep track of them and conditionnaly create
the ftrace format strings section (reported by Steven Rostedt) ]
Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Acked-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
LKML-Reference: <1236356510-8381-4-git-send-email-fweisbec@xxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
include/asm-generic/vmlinux.lds.h | 9 ++++
include/linux/ftrace.h | 21 +++++++++
include/linux/module.h | 5 ++
kernel/module.c | 6 +++
kernel/trace/trace.c | 15 ++++++
kernel/trace/trace_bprintk.c | 87 ++++++++++++++++++++++++++++++++----
6 files changed, 133 insertions(+), 10 deletions(-)
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 0add6b2..48ade31 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -69,6 +69,14 @@
#define FTRACE_EVENTS()
#endif
+#ifdef CONFIG_TRACING
+#define TRACE_PRINTKS() VMLINUX_SYMBOL(__start___trace_bprintk_fmt) = .; \
+ *(__trace_printk_fmt) /* Trace_printk fmt' pointer */ \
+ VMLINUX_SYMBOL(__stop___trace_bprintk_fmt) = .;
+#else
+#define TRACE_PRINTKS()
+#endif
+
/* .data section */
#define DATA_DATA \
*(.data) \
@@ -100,6 +108,7 @@
*(__vermagic) /* Kernel version magic */ \
*(__markers_strings) /* Markers: strings */ \
*(__tracepoints_strings)/* Tracepoints: strings */ \
+ TRACE_PRINTKS() \
} \
\
.rodata1 : AT(ADDR(.rodata1) - LOAD_OFFSET) { \
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 1c9cdca..1cc8ca4 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -225,6 +225,27 @@ extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
#ifdef CONFIG_TRACE_BPRINTK
extern int trace_vbprintk(unsigned long ip, const char *fmt, va_list args);
+extern int __trace_bprintk(unsigned long ip, const char *fmt, ...)
+ __attribute__ ((format (printf, 2, 3)));
+
+static inline void ____trace_bprintk_check_format(const char *fmt, ...)
+ __attribute__ ((format (printf, 1, 2)));
+static inline void ____trace_bprintk_check_format(const char *fmt, ...) {}
+#define __trace_bprintk_check_format(fmt, args...) \
+do { \
+ if (0) \
+ ____trace_bprintk_check_format(fmt, ##args); \
+} while (0)
+
+#define trace_bprintk(fmt, args...) \
+do { \
+ static char *__attribute__((section("__trace_bprintk_fmt"))) \
+ trace_bprintk_fmt = fmt; \
+ __trace_bprintk_check_format(fmt, ##args); \
+ __trace_bprintk(_THIS_IP_, trace_bprintk_fmt, ##args); \
+} while (0)
+#else
+#define trace_bprintk trace_printk
#endif
/* May be defined in arch */
diff --git a/include/linux/module.h b/include/linux/module.h
index 145a755..8cbec97 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -329,6 +329,11 @@ struct module
unsigned int num_tracepoints;
#endif
+#ifdef CONFIG_TRACE_BPRINTK
+ const char **trace_bprintk_fmt_start;
+ unsigned int num_trace_bprintk_fmt;
+#endif
+
#ifdef CONFIG_MODULE_UNLOAD
/* What modules depend on me? */
struct list_head modules_which_use_me;
diff --git a/kernel/module.c b/kernel/module.c
index 22d7379..2dece10 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2158,6 +2158,12 @@ static noinline struct module *load_module(void __user *umod,
&mod->num_tracepoints);
#endif
+#ifdef CONFIG_TRACE_BPRINTK
+ mod->trace_bprintk_fmt_start = section_objs(hdr, sechdrs, secstrings,
+ "__trace_bprintk_fmt", sizeof(char *),
+ &mod->num_trace_bprintk_fmt);
+#endif
+
#ifdef CONFIG_MODVERSIONS
if ((mod->num_syms && !mod->crcs)
|| (mod->num_gpl_syms && !mod->gpl_crcs)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index ff53509..46b3cd7 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3848,6 +3848,21 @@ out:
}
EXPORT_SYMBOL_GPL(trace_vbprintk);
+int __trace_bprintk(unsigned long ip, const char *fmt, ...)
+{
+ int ret;
+ va_list ap;
+
+ if (!fmt)
+ return 0;
+
+ va_start(ap, fmt);
+ ret = trace_vbprintk(ip, fmt, ap);
+ va_end(ap);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(__trace_bprintk);
+
static int trace_panic_handler(struct notifier_block *this,
unsigned long event, void *unused)
{
diff --git a/kernel/trace/trace_bprintk.c b/kernel/trace/trace_bprintk.c
index 1f8e532..f4c245a 100644
--- a/kernel/trace/trace_bprintk.c
+++ b/kernel/trace/trace_bprintk.c
@@ -19,9 +19,21 @@
#include "trace.h"
+#ifdef CONFIG_MODULES
+
/* binary printk basic */
static DEFINE_MUTEX(btrace_mutex);
-static int btrace_metadata_count;
+/*
+ * modules trace_bprintk()'s formats are autosaved in struct trace_bprintk_fmt
+ * which are queued on trace_bprintk_fmt_list.
+ */
+static LIST_HEAD(trace_bprintk_fmt_list);
+
+struct trace_bprintk_fmt {
+ struct list_head list;
+ char fmt[0];
+};
+
static inline void lock_btrace(void)
{
@@ -33,26 +45,75 @@ static inline void unlock_btrace(void)
mutex_unlock(&btrace_mutex);
}
-static void get_btrace_metadata(void)
+
+static inline struct trace_bprintk_fmt *lookup_format(const char *fmt)
{
- lock_btrace();
- btrace_metadata_count++;
- unlock_btrace();
+ struct trace_bprintk_fmt *pos;
+ list_for_each_entry(pos, &trace_bprintk_fmt_list, list) {
+ if (!strcmp(pos->fmt, fmt))
+ return pos;
+ }
+ return NULL;
}
-static void put_btrace_metadata(void)
+static
+void hold_module_trace_bprintk_format(const char **start, const char **end)
{
+ const char **iter;
lock_btrace();
- btrace_metadata_count--;
+ for (iter = start; iter < end; iter++) {
+ struct trace_bprintk_fmt *tb_fmt = lookup_format(*iter);
+ if (tb_fmt) {
+ *iter = tb_fmt->fmt;
+ continue;
+ }
+
+ tb_fmt = kmalloc(offsetof(struct trace_bprintk_fmt, fmt)
+ + strlen(*iter) + 1, GFP_KERNEL);
+ if (tb_fmt) {
+ list_add_tail(&tb_fmt->list, &trace_bprintk_fmt_list);
+ strcpy(tb_fmt->fmt, *iter);
+ *iter = tb_fmt->fmt;
+ } else
+ *iter = NULL;
+ }
unlock_btrace();
}
+static int module_trace_bprintk_format_notify(struct notifier_block *self,
+ unsigned long val, void *data)
+{
+ struct module *mod = data;
+ if (mod->num_trace_bprintk_fmt) {
+ const char **start = mod->trace_bprintk_fmt_start;
+ const char **end = start + mod->num_trace_bprintk_fmt;
+
+ if (val == MODULE_STATE_COMING)
+ hold_module_trace_bprintk_format(start, end);
+ }
+ return 0;
+}
+
+#else /* !CONFIG_MODULES */
+__init static int
+module_trace_bprintk_format_notify(struct notifier_block *self,
+ unsigned long val, void *data)
+{
+ return 0;
+}
+#endif /* CONFIG_MODULES */
+
+
+__initdata_or_module static
+struct notifier_block module_trace_bprintk_format_nb = {
+ .notifier_call = module_trace_bprintk_format_notify,
+};
+
/* events tracer */
int trace_bprintk_enable;
static void start_bprintk_trace(struct trace_array *tr)
{
- get_btrace_metadata();
tracing_reset_online_cpus(tr);
trace_bprintk_enable = 1;
}
@@ -61,7 +122,6 @@ static void stop_bprintk_trace(struct trace_array *tr)
{
trace_bprintk_enable = 0;
tracing_reset_online_cpus(tr);
- put_btrace_metadata();
}
static int init_bprintk_trace(struct trace_array *tr)
@@ -81,7 +141,14 @@ static struct tracer bprintk_trace __read_mostly =
static __init int init_bprintk(void)
{
- return register_tracer(&bprintk_trace);
+ int ret = register_module_notifier(&module_trace_bprintk_format_nb);
+ if (ret)
+ return ret;
+
+ ret = register_tracer(&bprintk_trace);
+ if (ret)
+ unregister_module_notifier(&module_trace_bprintk_format_nb);
+ return ret;
}
device_initcall(init_bprintk);
--
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