[PATCH 4/8] perf probe ppc64le: Fix ppc64 ABIv2 symbol decoding

tim.gardner at canonical.com tim.gardner at canonical.com
Fri Sep 11 14:42:28 UTC 2015


From: Ananth N Mavinakayanahalli <ananth at in.ibm.com>

BugLink: http://bugs.launchpad.net/bugs/1485528

ppc64 ELF ABIv2 has a Global Entry Point (GEP) and a Local Entry Point
(LEP). For purposes of probing, we need the LEP - the offset to which is
encoded in st_other.

Signed-off-by: Ananth N Mavinakayanahalli <ananth at in.ibm.com>
Reviewed-by: Srikar Dronamraju <srikar at linux.vnet.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/ab9cc5e2b9de4cbaaf50f6ef2346a6a81100bad1.1430217967.git.naveen.n.rao@linux.vnet.ibm.com
Signed-off-by: Naveen N. Rao <naveen.n.rao at linux.vnet.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme at redhat.com>
(cherry picked from commit c50fc0a43e33a6c3257c5cbb954cd747d7b9a680)
Signed-off-by: Tim Gardner <tim.gardner at canonical.com>
---
 tools/perf/arch/powerpc/util/sym-handling.c | 7 +++++++
 tools/perf/util/symbol-elf.c                | 4 ++++
 tools/perf/util/symbol.h                    | 1 +
 3 files changed, 12 insertions(+)

diff --git a/tools/perf/arch/powerpc/util/sym-handling.c b/tools/perf/arch/powerpc/util/sym-handling.c
index 2de2cc4..012a0f8 100644
--- a/tools/perf/arch/powerpc/util/sym-handling.c
+++ b/tools/perf/arch/powerpc/util/sym-handling.c
@@ -17,6 +17,13 @@ bool elf__needs_adjust_symbols(GElf_Ehdr ehdr)
 	       ehdr.e_type == ET_REL ||
 	       ehdr.e_type == ET_DYN;
 }
+
+#if defined(_CALL_ELF) && _CALL_ELF == 2
+void arch__elf_sym_adjust(GElf_Sym *sym)
+{
+	sym->st_value += PPC64_LOCAL_ENTRY_OFFSET(sym->st_other);
+}
+#endif
 #endif
 
 #if !defined(_CALL_ELF) || _CALL_ELF != 2
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 32de043..3ce8ddf 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -748,6 +748,8 @@ static bool want_demangle(bool is_kernel_sym)
 	return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
 }
 
+void __weak arch__elf_sym_adjust(GElf_Sym *sym __maybe_unused) { }
+
 int dso__load_sym(struct dso *dso, struct map *map,
 		  struct symsrc *syms_ss, struct symsrc *runtime_ss,
 		  symbol_filter_t filter, int kmodule)
@@ -909,6 +911,8 @@ int dso__load_sym(struct dso *dso, struct map *map,
 		    (sym.st_value & 1))
 			--sym.st_value;
 
+		arch__elf_sym_adjust(&sym);
+
 		if (dso->kernel || kmodule) {
 			char dso_name[PATH_MAX];
 
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index 38a965d..08bf1df 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -298,6 +298,7 @@ int setup_list(struct strlist **list, const char *list_str,
 
 #ifdef HAVE_LIBELF_SUPPORT
 bool elf__needs_adjust_symbols(GElf_Ehdr ehdr);
+void arch__elf_sym_adjust(GElf_Sym *sym);
 #endif
 
 #define SYMBOL_A 0
-- 
1.9.1





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