tracing: Kprobe-tracer supports more than 6 arguments

Support up to 128 arguments to fetch for each kprobes event.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: 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: <20090813203518.31965.96979.stgit@localhost.localdomain>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

1 files changed, 13 insertions, 8 deletions

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 0c4f00aafb9..6d488efd16b 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -32,7 +32,7 @@
 #include "trace.h"
 #include "trace_output.h"
 
-#define TRACE_KPROBE_ARGS 6
+#define MAX_TRACE_ARGS 128
 #define MAX_ARGSTR_LEN 63
 
 /* currently, trace_kprobe only supports X86. */
@@ -184,11 +184,15 @@ struct trace_probe {
                 struct kretprobe        rp;
         };
         const char              *symbol;        /* symbol name */
-        unsigned int            nr_args;
-        struct fetch_func       args[TRACE_KPROBE_ARGS];
         struct ftrace_event_call        call;
+        unsigned int            nr_args;
+        struct fetch_func       args[];
 };
 
+#define SIZEOF_TRACE_PROBE(n)                   \
+        (offsetof(struct trace_probe, args) +   \
+        (sizeof(struct fetch_func) * (n)))
+
 static int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs);
 static int kretprobe_trace_func(struct kretprobe_instance *ri,
                                 struct pt_regs *regs);
@@ -263,11 +267,11 @@ static DEFINE_MUTEX(probe_lock);
 static LIST_HEAD(probe_list);
 
 static struct trace_probe *alloc_trace_probe(const char *symbol,
-                                             const char *event)
+                                             const char *event, int nargs)
 {
         struct trace_probe *tp;
 
-        tp = kzalloc(sizeof(struct trace_probe), GFP_KERNEL);
+        tp = kzalloc(SIZEOF_TRACE_PROBE(nargs), GFP_KERNEL);
         if (!tp)
                 return ERR_PTR(-ENOMEM);
 
@@ -573,9 +577,10 @@ static int create_trace_probe(int argc, char **argv)
                 if (offset && is_return)
                         return -EINVAL;
         }
+        argc -= 2; argv += 2;
 
         /* setup a probe */
-        tp = alloc_trace_probe(symbol, event);
+        tp = alloc_trace_probe(symbol, event, argc);
         if (IS_ERR(tp))
                 return PTR_ERR(tp);
 
@@ -594,8 +599,8 @@ static int create_trace_probe(int argc, char **argv)
                 kp->addr = addr;
 
         /* parse arguments */
-        argc -= 2; argv += 2; ret = 0;
-        for (i = 0; i < argc && i < TRACE_KPROBE_ARGS; i++) {
+        ret = 0;
+        for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
                 if (strlen(argv[i]) > MAX_ARGSTR_LEN) {
                         pr_info("Argument%d(%s) is too long.\n", i, argv[i]);
                         ret = -ENOSPC;