perf probe ppc: Enable matching against dot symbols automatically

Allow perf probe to work on ppc ABIv1 without the need to specify the
leading dot '.' for functions. 'perf probe do_fork' works with this
patch.

We do this by changing how symbol name comparison works on ppc ABIv1 -
we simply ignore and skip over the initial dot, if one exists, during
symbol name comparison.

Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/652a8f3bfa919bd02a1836a128370eaed59b4a34.1430217967.git.naveen.n.rao@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/arch/powerpc/util/sym-handling.c b/tools/perf/arch/powerpc/util/sym-handling.c
index 5522a4000c228014910c10351c90d6d7e673ffde..2de2cc484d6ec33c19303781de2f9b2a6b653dd4 100644 (file)
--- a/tools/perf/arch/powerpc/util/sym-handling.c
+++ b/tools/perf/arch/powerpc/util/sym-handling.c
@@ -8,6 +8,7 @@
 
 #include "debug.h"
 #include "symbol.h"
+#include "map.h"
 
 #ifdef HAVE_LIBELF_SUPPORT
 bool elf__needs_adjust_symbols(GElf_Ehdr ehdr)
@@ -36,4 +37,16 @@ int arch__choose_best_symbol(struct symbol *syma,
 
        return SYMBOL_A;
 }
+
+/* Allow matching against dot variants */
+int arch__compare_symbol_names(const char *namea, const char *nameb)
+{
+       /* Skip over initial dot */
+       if (*namea == '.')
+               namea++;
+       if (*nameb == '.')
+               nameb++;
+
+       return strcmp(namea, nameb);
+}
 #endif

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index a14f08f416863944527412b82a6b3cfaeda3c603..cd0e335008b44ec76c1e965e4759117ffe56feaf 100644 (file)
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -292,6 +292,11 @@ int map__load(struct map *map, symbol_filter_t filter)
        return 0;
 }
 
+int __weak arch__compare_symbol_names(const char *namea, const char *nameb)
+{
+       return strcmp(namea, nameb);
+}
+
 struct symbol *map__find_symbol(struct map *map, u64 addr,
                                symbol_filter_t filter)
 {

diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
index ec19c59ca38e07deba4a8c2c254ec3a4c71c6c91..4e0c729841ab15e7efca9ecbc67f61bbc39e2d18 100644 (file)
--- a/tools/perf/util/map.h
+++ b/tools/perf/util/map.h
@@ -124,7 +124,7 @@ struct thread;
  */
 #define __map__for_each_symbol_by_name(map, sym_name, pos, filter)     \
        for (pos = map__find_symbol_by_name(map, sym_name, filter);     \
-            pos && strcmp(pos->name, sym_name) == 0;           \
+            pos && arch__compare_symbol_names(pos->name, sym_name) == 0;       \
             pos = symbol__next_by_name(pos))
 
 #define map__for_each_symbol_by_name(map, sym_name, pos)               \
@@ -132,6 +132,7 @@ struct thread;
 
 typedef int (*symbol_filter_t)(struct map *map, struct symbol *sym);
 
+int arch__compare_symbol_names(const char *namea, const char *nameb);
 void map__init(struct map *map, enum map_type type,
               u64 start, u64 end, u64 pgoff, struct dso *dso);
 struct map *map__new(struct machine *machine, u64 start, u64 len,

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index f80575728c6484a38eeb666fa25da40c28449862..45ba48a7acb3b2de76dab11a95cd2880f1a11ce7 100644 (file)
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -411,7 +411,7 @@ static struct symbol *symbols__find_by_name(struct rb_root *symbols,
                int cmp;
 
                s = rb_entry(n, struct symbol_name_rb_node, rb_node);
-               cmp = strcmp(name, s->sym.name);
+               cmp = arch__compare_symbol_names(name, s->sym.name);
 
                if (cmp < 0)
                        n = n->rb_left;
@@ -429,7 +429,7 @@ static struct symbol *symbols__find_by_name(struct rb_root *symbols,
                struct symbol_name_rb_node *tmp;
 
                tmp = rb_entry(n, struct symbol_name_rb_node, rb_node);
-               if (strcmp(tmp->sym.name, s->sym.name))
+               if (arch__compare_symbol_names(tmp->sym.name, s->sym.name))
                        break;
 
                s = tmp;