[PATCH 02/21] perf probe ppc: Use the right prefix when ignoring SyS symbols on ppc

[Arnaldo Carvalho de Melo]

From: "Naveen N. Rao" <naveen.n.rao at linux.vnet.ibm.com>

Use the proper prefix when ignoring SyS symbols on ppc ABIv1. While at
it, generalize symbol selection so architectures can implement their own
logic.

Signed-off-by: Naveen N. Rao <naveen.n.rao at linux.vnet.ibm.com>
Reviewed-by: Srikar Dronamraju <srikar at linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth at in.ibm.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt at hitachi.com>
Cc: Michael Ellerman <mpe at ellerman.id.au>
Cc: Sukadev Bhattiprolu <sukadev at linux.vnet.ibm.com>
Cc: linuxppc-dev at lists.ozlabs.org
Link: http://lkml.kernel.org/r/adf1f98b121ecaf292777fe5cc69fe1038feabce.1430217967.git.naveen.n.rao@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme at redhat.com>
---
 tools/perf/arch/powerpc/util/sym-handling.c | 20 ++++++++++++++++++++
 tools/perf/util/symbol.c                    | 21 ++++++++++++---------
 tools/perf/util/symbol.h                    |  5 +++++
 3 files changed, 37 insertions(+), 9 deletions(-)

diff --git a/tools/perf/arch/powerpc/util/sym-handling.c b/tools/perf/arch/powerpc/util/sym-handling.c
index c9de001..5522a40 100644
--- a/tools/perf/arch/powerpc/util/sym-handling.c
+++ b/tools/perf/arch/powerpc/util/sym-handling.c
@@ -17,3 +17,23 @@ bool elf__needs_adjust_symbols(GElf_Ehdr ehdr)
 	       ehdr.e_type == ET_DYN;
 }
 #endif
+
+#if !defined(_CALL_ELF) || _CALL_ELF != 2
+int arch__choose_best_symbol(struct symbol *syma,
+			     struct symbol *symb __maybe_unused)
+{
+	char *sym = syma->name;
+
+	/* Skip over any initial dot */
+	if (*sym == '.')
+		sym++;
+
+	/* Avoid "SyS" kernel syscall aliases */
+	if (strlen(sym) >= 3 && !strncmp(sym, "SyS", 3))
+		return SYMBOL_B;
+	if (strlen(sym) >= 10 && !strncmp(sym, "compat_SyS", 10))
+		return SYMBOL_B;
+
+	return SYMBOL_A;
+}
+#endif
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 201f6c4c..f805757 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -85,8 +85,17 @@ static int prefix_underscores_count(const char *str)
 	return tail - str;
 }
 
-#define SYMBOL_A 0
-#define SYMBOL_B 1
+int __weak arch__choose_best_symbol(struct symbol *syma,
+				    struct symbol *symb __maybe_unused)
+{
+	/* Avoid "SyS" kernel syscall aliases */
+	if (strlen(syma->name) >= 3 && !strncmp(syma->name, "SyS", 3))
+		return SYMBOL_B;
+	if (strlen(syma->name) >= 10 && !strncmp(syma->name, "compat_SyS", 10))
+		return SYMBOL_B;
+
+	return SYMBOL_A;
+}
 
 static int choose_best_symbol(struct symbol *syma, struct symbol *symb)
 {
@@ -134,13 +143,7 @@ static int choose_best_symbol(struct symbol *syma, struct symbol *symb)
 	else if (na < nb)
 		return SYMBOL_B;
 
-	/* Avoid "SyS" kernel syscall aliases */
-	if (na >= 3 && !strncmp(syma->name, "SyS", 3))
-		return SYMBOL_B;
-	if (na >= 10 && !strncmp(syma->name, "compat_SyS", 10))
-		return SYMBOL_B;
-
-	return SYMBOL_A;
+	return arch__choose_best_symbol(syma, symb);
 }
 
 void symbols__fixup_duplicate(struct rb_root *symbols)
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index 8cb0af4..bd50ba0 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -307,4 +307,9 @@ int setup_intlist(struct intlist **list, const char *list_str,
 bool elf__needs_adjust_symbols(GElf_Ehdr ehdr);
 #endif
 
+#define SYMBOL_A 0
+#define SYMBOL_B 1
+
+int arch__choose_best_symbol(struct symbol *syma, struct symbol *symb);
+
 #endif /* __PERF_SYMBOL */
-- 
2.1.0