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authorMasami Hiramatsu <mhiramat@kernel.org>2019-11-18 09:12:40 +0100
committerArnaldo Carvalho de Melo <acme@redhat.com>2019-11-18 23:08:02 +0100
commit66f69b2197167cb99330c77a550da50f1f597abc (patch)
treed804ea39d77cac08c62a62b755f8176d0e9ba771 /tools/perf/util/probe-finder.c
parentperf probe: Support multiprobe event (diff)
downloadlinux-66f69b2197167cb99330c77a550da50f1f597abc.tar.xz
linux-66f69b2197167cb99330c77a550da50f1f597abc.zip
perf probe: Support DW_AT_const_value constant value
Support DW_AT_const_value for variable assignment instead of location. Note that this requires ftrace supporting immediate value. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Link: http://lore.kernel.org/lkml/157406476012.24476.16096289871757175775.stgit@devnote2 Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/probe-finder.c')
-rw-r--r--tools/perf/util/probe-finder.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index f12ad507a822..33e90054ad84 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -177,6 +177,17 @@ static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
goto static_var;
+ /* Constant value */
+ if (dwarf_attr(vr_die, DW_AT_const_value, &attr) &&
+ immediate_value_is_supported()) {
+ Dwarf_Sword snum;
+
+ dwarf_formsdata(&attr, &snum);
+ ret = asprintf(&tvar->value, "\\%ld", (long)snum);
+
+ return ret < 0 ? -ENOMEM : 0;
+ }
+
/* TODO: handle more than 1 exprs */
if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
return -EINVAL; /* Broken DIE ? */