When probing at function entry, fallback $params to calling regs if no
debuginfo is provided.
Before this path:
$ perf probe -v --add='generic_perform_write $params'
...
Added new event:
Writing event: p:probe/generic_perform_write _stext+1246632 $params
[86152.161204] Parse error at argument[0]. (-22)
Failed to write event: Invalid argument
Error: Failed to add events. Reason: Invalid argument (Code: -22)
After this patch:
$ perf probe -v --add='generic_perform_write $params'
...
Could not open debuginfo. Try to use symbols.
...
Added new event:
Writing event: p:probe/generic_perform_write _stext+1246632 %di %si %dx %cx
%r8 %r9
probe:generic_perform_write (on generic_perform_write with $params)
You can now use it in all perf tools, such as:
perf record -e probe:generic_perform_write -aR sleep 1
$ perf record -e probe:generic_perform_write dd if=/dev/zero
of=/mnt/data/test bs=4k count=3
$ perf script
dd 1149 [000] 18574.762652: probe:generic_perform_write: (ffffffff81130770)
arg1=0xffff88007c37f600 arg2=0xffff88007ca87e70 arg3=0x0 arg4=0x0
arg5=0x556062e3 arg6=0x12a8010
dd 1149 [000] 18574.762652: probe:generic_perform_write: (ffffffff81130770)
arg1=0xffff88007c37f600 arg2=0xffff88007ca87e70 arg3=0x1000 arg4=0x0
arg5=0x556062e3 arg6=0x12a8010
dd 1149 [000] 18574.762652: probe:generic_perform_write: (ffffffff81130770)
arg1=0xffff88007c37f600 arg2=0xffff88007ca87e70 arg3=0x2000 arg4=0x0
arg5=0x556062e3 arg6=0x12a8010
Signed-off-by: He Kuang <heku...@huawei.com>
---
tools/perf/util/probe-event.c | 42 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 42 insertions(+)
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index d05b77c..7f9f431 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -46,6 +46,7 @@
#include "probe-event.h"
#include "probe-finder.h"
#include "session.h"
+#include <dwarf-regs.h>
#define MAX_CMDLEN 256
#define PERFPROBE_GROUP "probe"
@@ -286,6 +287,14 @@ static void clear_probe_trace_events(struct
probe_trace_event *tevs, int ntevs)
clear_probe_trace_event(tevs + i);
}
+static bool perf_probe_is_function_entry(struct perf_probe_event *pev)
+{
+ if (pev->point.file || pev->point.line || pev->point.lazy_line)
+ return false;
+
+ return true;
+}
+
#ifdef HAVE_DWARF_SUPPORT
/*
* Some binaries like glibc have special symbols which are on the symbol
@@ -1225,6 +1234,33 @@ static int parse_perf_probe_point(char *arg, struct
perf_probe_event *pev)
return 0;
}
+static char *parse_perf_probe_param(void)
+{
+ int i = 0;
+ struct strbuf sb;
+ bool first = true;
+ const char *reg_str;
+
+ strbuf_init(&sb, 16);
+
+ while (1) {
+ reg_str = get_arch_calling_reg_str(i++);
+ if (!reg_str)
+ break;
+
+ if (first) {
+ strbuf_addf(&sb, "%s", reg_str);
+ first = false;
+ } else
+ strbuf_addf(&sb, " %s", reg_str);
+ }
+
+ if (first)
+ strbuf_add(&sb, "", 1);
+
+ return strbuf_detach(&sb, NULL);
+}
+
/* Parse perf-probe event argument */
static int parse_perf_probe_arg(char *str, struct perf_probe_arg *arg)
{
@@ -2543,6 +2579,12 @@ static int find_probe_trace_events_from_map(struct
perf_probe_event *pev,
goto nomem_out;
}
for (i = 0; i < tev->nargs; i++) {
+ if (perf_probe_is_function_entry(pev) &&
+ !strcmp(pev->args[i].var, "$params")) {
+ tev->args[i].value = parse_perf_probe_param();
+ continue;
+ }
+
if (pev->args[i].name)
tev->args[i].name =
strdup_or_goto(pev->args[i].name,
--
1.8.5.2
--
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