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, 12 insertions, 0 deletions

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 06be85a7ef8c..fb5fbf75f279 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -411,6 +411,18 @@ config BLK_DEV_IO_TRACE
 
           If unsure, say N.
 
+config KPROBE_TRACER
+        depends on KPROBES
+        depends on X86
+        bool "Trace kprobes"
+        select TRACING
+        select GENERIC_TRACER
+        help
+          This tracer probes everywhere where kprobes can probe it, and
+          records various registers and memories specified by user.
+          This also allows you to trace kprobe probe points as a dynamic
+          defined events. It provides per-probe event filtering interface.
+
 config DYNAMIC_FTRACE
         bool "enable/disable ftrace tracepoints dynamically"
         depends on FUNCTION_TRACER