diff options
| author | Masami Hiramatsu <mhiramat@kernel.org> | 2019-11-18 17:12:40 +0900 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2019-11-18 19:08:02 -0300 |
| commit | 66f69b2197167cb99330c77a550da50f1f597abc (patch) | |
| tree | d804ea39d77cac08c62a62b755f8176d0e9ba771 | |
| parent | 72363540c009db5014252a1a15e149d30f88bcc3 (diff) | |
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>
| -rw-r--r-- | tools/perf/util/probe-file.c | 7 | ||||
| -rw-r--r-- | tools/perf/util/probe-file.h | 1 | ||||
| -rw-r--r-- | tools/perf/util/probe-finder.c | 11 |
3 files changed, 19 insertions, 0 deletions
diff --git a/tools/perf/util/probe-file.c b/tools/perf/util/probe-file.c index a63f1a19b0e8..5003ba403345 100644 --- a/tools/perf/util/probe-file.c +++ b/tools/perf/util/probe-file.c @@ -1008,6 +1008,7 @@ enum ftrace_readme { FTRACE_README_UPROBE_REF_CTR, FTRACE_README_USER_ACCESS, FTRACE_README_MULTIPROBE_EVENT, + FTRACE_README_IMMEDIATE_VALUE, FTRACE_README_END, }; @@ -1022,6 +1023,7 @@ static struct { DEFINE_TYPE(FTRACE_README_UPROBE_REF_CTR, "*ref_ctr_offset*"), DEFINE_TYPE(FTRACE_README_USER_ACCESS, "*[u]<offset>*"), DEFINE_TYPE(FTRACE_README_MULTIPROBE_EVENT, "*Create/append/*"), + DEFINE_TYPE(FTRACE_README_IMMEDIATE_VALUE, "*\\imm-value,*"), }; static bool scan_ftrace_readme(enum ftrace_readme type) @@ -1092,3 +1094,8 @@ bool multiprobe_event_is_supported(void) { return scan_ftrace_readme(FTRACE_README_MULTIPROBE_EVENT); } + +bool immediate_value_is_supported(void) +{ + return scan_ftrace_readme(FTRACE_README_IMMEDIATE_VALUE); +} diff --git a/tools/perf/util/probe-file.h b/tools/perf/util/probe-file.h index 850d1b52d60a..0dba88c0f5f0 100644 --- a/tools/perf/util/probe-file.h +++ b/tools/perf/util/probe-file.h @@ -72,6 +72,7 @@ bool kretprobe_offset_is_supported(void); bool uprobe_ref_ctr_is_supported(void); bool user_access_is_supported(void); bool multiprobe_event_is_supported(void); +bool immediate_value_is_supported(void); #else /* ! HAVE_LIBELF_SUPPORT */ static inline struct probe_cache *probe_cache__new(const char *tgt __maybe_unused, struct nsinfo *nsi __maybe_unused) { 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 ? */ |