Commit 4b3a2716 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Arnaldo Carvalho de Melo
Browse files

perf probe: Find versioned symbols from map 



Commit d8040645 ("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: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: default avatarThomas Richter <tmricht@linux.vnet.ibm.com>
Acked-by: default avatarRavi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Tested-by: default avatarArnaldo 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: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent e63c625a

tools/perf/arch/powerpc/util/sym-handling.c

+8 −0
Original line number Diff line number Diff line
@@ -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

tools/perf/util/probe-event.c

+18 −2
Original line number Diff line number Diff line
@@ -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;

tools/perf/util/symbol.c

+5 −0
Original line number Diff line number Diff line
@@ -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);

tools/perf/util/symbol.h

+1 −0
Original line number Diff line number Diff line
@@ -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

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