perf probe: Find versioned symbols from map

Commit d80406453ad4 ("perf symbols: Allow user probes on versioned
symbols") allows user to find default versioned symbols (with "@@") in
map. However, it did not enable normal versioned symbol (with "@") for
perf-probe.  E.g.

  =====
  # ./perf probe -x /lib64/libc-2.25.so malloc_get_state
  Failed to find symbol malloc_get_state in /usr/lib64/libc-2.25.so
    Error: Failed to add events.
  =====

This solves above issue by improving perf-probe symbol search function,
as below.

  =====
  # ./perf probe -x /lib64/libc-2.25.so malloc_get_state
  Added new event:
    probe_libc:malloc_get_state (on malloc_get_state in /usr/lib64/libc-2.25.so)

  You can now use it in all perf tools, such as:

	  perf record -e probe_libc:malloc_get_state -aR sleep 1

  # ./perf probe -l
    probe_libc:malloc_get_state (on malloc_get_state@GLIBC_2.2.5 in /usr/lib64/libc-2.25.so)
  =====

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Acked-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: bhargavb <bhargavaramudu@gmail.com>
Cc: linux-rt-users@vger.kernel.org
Link: http://lkml.kernel.org/r/151275049269.24652.1639103455496216255.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

4 files changed, 32 insertions, 2 deletions

diff --git a/tools/perf/arch/powerpc/util/sym-handling.c b/tools/perf/arch/powerpc/util/sym-handling.c
index 9c4e23d8c8ce..53d83d7e6a09 100644
--- a/tools/perf/arch/powerpc/util/sym-handling.c
+++ b/tools/perf/arch/powerpc/util/sym-handling.c
@@ -64,6 +64,14 @@ int arch__compare_symbol_names_n(const char *namea, const char *nameb,
 
         return strncmp(namea, nameb, n);
 }
+
+const char *arch__normalize_symbol_name(const char *name)
+{
+        /* Skip over initial dot */
+        if (name && *name == '.')
+                name++;
+        return name;
+}
 #endif
 
 #if defined(_CALL_ELF) && _CALL_ELF == 2
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index a68141d360b0..0d6c66d51939 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2801,16 +2801,32 @@ static int find_probe_functions(struct map *map, char *name,
         int found = 0;
         struct symbol *sym;
         struct rb_node *tmp;
+        const char *norm, *ver;
+        char *buf = NULL;
 
         if (map__load(map) < 0)
                 return 0;
 
         map__for_each_symbol(map, sym, tmp) {
-                if (strglobmatch(sym->name, name)) {
+                norm = arch__normalize_symbol_name(sym->name);
+                if (!norm)
+                        continue;
+
+                /* We don't care about default symbol or not */
+                ver = strchr(norm, '@');
+                if (ver) {
+                        buf = strndup(norm, ver - norm);
+                        if (!buf)
+                                return -ENOMEM;
+                        norm = buf;
+                }
+                if (strglobmatch(norm, name)) {
                         found++;
                         if (syms && found < probe_conf.max_probes)
                                 syms[found - 1] = sym;
                 }
+                if (buf)
+                        zfree(&buf);
         }
 
         return found;
@@ -2856,7 +2872,7 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
          * same name but different addresses, this lists all the symbols.
          */
         num_matched_functions = find_probe_functions(map, pp->function, syms);
-        if (num_matched_functions == 0) {
+        if (num_matched_functions <= 0) {
                 pr_err("Failed to find symbol %s in %s\n", pp->function,
                         pev->target ? : "kernel");
                 ret = -ENOENT;
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 1b67a8639dfe..cc065d4bfafc 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -94,6 +94,11 @@ static int prefix_underscores_count(const char *str)
         return tail - str;
 }
 
+const char * __weak arch__normalize_symbol_name(const char *name)
+{
+        return name;
+}
+
 int __weak arch__compare_symbol_names(const char *namea, const char *nameb)
 {
         return strcmp(namea, nameb);
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index a4f0075b4e5c..0563f33c1eb3 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -349,6 +349,7 @@ bool elf__needs_adjust_symbols(GElf_Ehdr ehdr);
 void arch__sym_update(struct symbol *s, GElf_Sym *sym);
 #endif
 
+const char *arch__normalize_symbol_name(const char *name);
 #define SYMBOL_A 0
 #define SYMBOL_B 1