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authorIngo Molnar <mingo@kernel.org>2013-09-03 07:41:11 +0200
committerIngo Molnar <mingo@kernel.org>2013-09-03 07:41:11 +0200
commit7d992feb7694a21ee81f22894b455dadd5d1c110 (patch)
treed0f0961186b1c31c536a26a7f986ad7ca677453b /kernel/trace
parent6e4664525b1db28f8c4e1130957f70a94c19213e (diff)
parent25f27ce4a6a4995c8bdd69b4b2180465ed5ad2b8 (diff)
Merge branch 'rcu/next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
Pull RCU updates from Paul E. McKenney: " * Update RCU documentation. These were posted to LKML at https://lkml.org/lkml/2013/8/19/611. * Miscellaneous fixes. These were posted to LKML at https://lkml.org/lkml/2013/8/19/619. * Full-system idle detection. This is for use by Frederic Weisbecker's adaptive-ticks mechanism. Its purpose is to allow the timekeeping CPU to shut off its tick when all other CPUs are idle. These were posted to LKML at https://lkml.org/lkml/2013/8/19/648. * Improve rcutorture test coverage. These were posted to LKML at https://lkml.org/lkml/2013/8/19/675. " Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace.h3
-rw-r--r--kernel/trace/trace_printk.c19
2 files changed, 22 insertions, 0 deletions
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index afaae41b0a02..fe39acd4c1aa 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1022,6 +1022,9 @@ extern struct list_head ftrace_events;
extern const char *__start___trace_bprintk_fmt[];
extern const char *__stop___trace_bprintk_fmt[];
+extern const char *__start___tracepoint_str[];
+extern const char *__stop___tracepoint_str[];
+
void trace_printk_init_buffers(void);
void trace_printk_start_comm(void);
int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set);
diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
index a9077c1b4ad3..2900817ba65c 100644
--- a/kernel/trace/trace_printk.c
+++ b/kernel/trace/trace_printk.c
@@ -244,12 +244,31 @@ static const char **find_next(void *v, loff_t *pos)
{
const char **fmt = v;
int start_index;
+ int last_index;
start_index = __stop___trace_bprintk_fmt - __start___trace_bprintk_fmt;
if (*pos < start_index)
return __start___trace_bprintk_fmt + *pos;
+ /*
+ * The __tracepoint_str section is treated the same as the
+ * __trace_printk_fmt section. The difference is that the
+ * __trace_printk_fmt section should only be used by trace_printk()
+ * in a debugging environment, as if anything exists in that section
+ * the trace_prink() helper buffers are allocated, which would just
+ * waste space in a production environment.
+ *
+ * The __tracepoint_str sections on the other hand are used by
+ * tracepoints which need to map pointers to their strings to
+ * the ASCII text for userspace.
+ */
+ last_index = start_index;
+ start_index = __stop___tracepoint_str - __start___tracepoint_str;
+
+ if (*pos < last_index + start_index)
+ return __start___tracepoint_str + (*pos - last_index);
+
return find_next_mod_format(start_index, v, fmt, pos);
}