[tip:perf/core] perf probe ppc: Use the right prefix when ignoring SyS symbols on ppc

["tip-bot for Naveen N. Rao" <tipbot@zytor.com>]

Commit-ID:  fb6d59423115b10125f5db6acb8471f6f0af4ad7
Gitweb:     http://git.kernel.org/tip/fb6d59423115b10125f5db6acb8471f6f0af4ad7
Author:     Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
AuthorDate: Tue, 28 Apr 2015 17:35:36 +0530
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Mon, 4 May 2015 12:43:43 -0300

perf probe ppc: Use the right prefix when ignoring SyS symbols on ppc

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@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/adf1f98b121ecaf292777fe5cc69fe1038feabce.1430217967.git.naveen.n.rao@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@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 */