From 203d8a4aa6edf2c19206316d439ec5dae52ce581 Mon Sep 17 00:00:00 2001 From: Song Shan Gong Date: Thu, 21 Jul 2016 11:10:51 +0800 Subject: [PATCH] perf s390: Fix 'start' address of module's map At present, when creating module's map, perf gets 'start' address by parsing '/proc/modules', but it's the module base address, it isn't the start address of the '.text' section. In most arches, it's OK. But for s390, it places 'GOT' and 'PLT' relocations before '.text' section. So there exists an offset between module base address and '.text' section, which will incur wrong symbol resolution for modules. Fix this bug by getting 'start' address of module's map from parsing '/sys/module/[module name]/sections/.text', not from '/proc/modules'. Signed-off-by: Song Shan Gong Acked-by: Jiri Olsa Cc: Christian Borntraeger Cc: David Ahern Link: http://lkml.kernel.org/r/1469070651-6447-2-git-send-email-gongss@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/arch/s390/util/Build | 2 ++ tools/perf/arch/s390/util/machine.c | 19 +++++++++++++++++++ tools/perf/util/machine.c | 8 ++++++++ tools/perf/util/machine.h | 1 + 4 files changed, 30 insertions(+) create mode 100644 tools/perf/arch/s390/util/machine.c diff --git a/tools/perf/arch/s390/util/Build b/tools/perf/arch/s390/util/Build index 8a61372bb47a..5bd7b9260cc0 100644 --- a/tools/perf/arch/s390/util/Build +++ b/tools/perf/arch/s390/util/Build @@ -2,3 +2,5 @@ libperf-y += header.o libperf-y += kvm-stat.o libperf-$(CONFIG_DWARF) += dwarf-regs.o + +libperf-y += machine.o diff --git a/tools/perf/arch/s390/util/machine.c b/tools/perf/arch/s390/util/machine.c new file mode 100644 index 000000000000..b9a95a1a8e69 --- /dev/null +++ b/tools/perf/arch/s390/util/machine.c @@ -0,0 +1,19 @@ +#include +#include +#include +#include "util.h" +#include "machine.h" +#include "api/fs/fs.h" + +int arch__fix_module_text_start(u64 *start, const char *name) +{ + char path[PATH_MAX]; + + snprintf(path, PATH_MAX, "module/%.*s/sections/.text", + (int)strlen(name) - 2, name + 1); + + if (sysfs__read_ull(path, (unsigned long long *)start) < 0) + return -1; + + return 0; +} diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index bc2cdbd09a25..cb6388dbdd98 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -1093,12 +1093,20 @@ static int machine__set_modules_path(struct machine *machine) return map_groups__set_modules_path_dir(&machine->kmaps, modules_path, 0); } +int __weak arch__fix_module_text_start(u64 *start __maybe_unused, + const char *name __maybe_unused) +{ + return 0; +} static int machine__create_module(void *arg, const char *name, u64 start) { struct machine *machine = arg; struct map *map; + if (arch__fix_module_text_start(&start, name) < 0) + return -1; + map = machine__findnew_module_map(machine, start, name); if (map == NULL) return -1; diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h index 41ac9cfd416b..20739f746bc4 100644 --- a/tools/perf/util/machine.h +++ b/tools/perf/util/machine.h @@ -216,6 +216,7 @@ struct symbol *machine__find_kernel_function_by_name(struct machine *machine, struct map *machine__findnew_module_map(struct machine *machine, u64 start, const char *filename); +int arch__fix_module_text_start(u64 *start, const char *name); int __machine__load_kallsyms(struct machine *machine, const char *filename, enum map_type type, bool no_kcore, symbol_filter_t filter);