tracing: Add kprobe-based event tracer

Add kprobes-based event tracer on ftrace.

This tracer is similar to the events tracer which is based on Tracepoint
infrastructure. Instead of Tracepoint, this tracer is based on kprobes
(kprobe and kretprobe). It probes anywhere where kprobes can probe(this
 means, all functions body except for __kprobes functions).

Similar to the events tracer, this tracer doesn't need to be activated
via current_tracer, instead of that, just set probe points via
/sys/kernel/debug/tracing/kprobe_events. And you can set filters on each
probe events via /sys/kernel/debug/tracing/events/kprobes/<EVENT>/filter.

This tracer supports following probe arguments for each probe.

  %REG  : Fetch register REG
  sN    : Fetch Nth entry of stack (N >= 0)
  sa    : Fetch stack address.
  @ADDR : Fetch memory at ADDR (ADDR should be in kernel)
  @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data symbol)
  aN    : Fetch function argument. (N >= 0)
  rv    : Fetch return value.
  ra    : Fetch return address.
  +|-offs(FETCHARG) : fetch memory at FETCHARG +|- offs address.

See Documentation/trace/kprobetrace.txt in the next patch for details.

Changes from v13:
 - Support 'sa' for stack address.
 - Use call->data instead of container_of() macro.

[fweisbec@gmail.com: Fixed conflict against latest tracing/core]

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Przemysław Pawełczyk <przemyslaw@pawelczyk.it>
Cc: Roland McGrath <roland@redhat.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
LKML-Reference: <20090813203510.31965.29123.stgit@localhost.localdomain>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 654fd657bd03..667f832d16b7 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -38,6 +38,8 @@ enum trace_type {
         TRACE_KMEM_FREE,
         TRACE_POWER,
         TRACE_BLK,
+        TRACE_KPROBE,
+        TRACE_KRETPROBE,
 
         __TRACE_LAST_TYPE,
 };
@@ -205,6 +207,30 @@ struct syscall_trace_exit {
         unsigned long           ret;
 };
 
+struct kprobe_trace_entry {
+        struct trace_entry      ent;
+        unsigned long           ip;
+        int                     nargs;
+        unsigned long           args[];
+};
+
+#define SIZEOF_KPROBE_TRACE_ENTRY(n)                    \
+        (offsetof(struct kprobe_trace_entry, args) +    \
+        (sizeof(unsigned long) * (n)))
+
+struct kretprobe_trace_entry {
+        struct trace_entry      ent;
+        unsigned long           func;
+        unsigned long           ret_ip;
+        int                     nargs;
+        unsigned long           args[];
+};
+
+#define SIZEOF_KRETPROBE_TRACE_ENTRY(n)                 \
+        (offsetof(struct kretprobe_trace_entry, args) + \
+        (sizeof(unsigned long) * (n)))
+
+
 
 /*
  * trace_flag_type is an enumeration that holds different
@@ -317,6 +343,10 @@ extern void __ftrace_bad_type(void);
                           TRACE_KMEM_ALLOC);    \
                 IF_ASSIGN(var, ent, struct kmemtrace_free_entry,        \
                           TRACE_KMEM_FREE);     \
+                IF_ASSIGN(var, ent, struct kprobe_trace_entry,          \
+                          TRACE_KPROBE);                                \
+                IF_ASSIGN(var, ent, struct kretprobe_trace_entry,       \
+                          TRACE_KRETPROBE);                             \
                 __ftrace_bad_type();                                    \
         } while (0)