From d9b62aba87a82939c73f451a166c7a21342350d6 Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Wed, 29 Jan 2014 16:14:43 +0200 Subject: [PATCH] perf tools: Adjust kallsyms for relocated kernel If the kernel is relocated at boot time, kallsyms will not match data recorded previously. That does not matter for modules because they are corrected anyway. It also does not matter if vmlinux is being used for symbols. But if perf tools has only kallsyms then the symbols will not match. Fix by applying the delta gained by comparing the old and current addresses of the relocation reference symbol. Signed-off-by: Adrian Hunter Tested-by: Jiri Olsa Cc: David Ahern Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Jiri Olsa Cc: Mike Galbraith Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lkml.kernel.org/r/1391004884-10334-9-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/symbol.c | 40 ++++++++++++++++++++++++++++++++++++++-- 1 file changed, 38 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index 4ac1f871ec27..a9d758a3b371 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -627,7 +627,7 @@ static int dso__split_kallsyms_for_kcore(struct dso *dso, struct map *map, * kernel range is broken in several maps, named [kernel].N, as we don't have * the original ELF section names vmlinux have. */ -static int dso__split_kallsyms(struct dso *dso, struct map *map, +static int dso__split_kallsyms(struct dso *dso, struct map *map, u64 delta, symbol_filter_t filter) { struct map_groups *kmaps = map__kmap(map)->kmaps; @@ -692,6 +692,12 @@ static int dso__split_kallsyms(struct dso *dso, struct map *map, char dso_name[PATH_MAX]; struct dso *ndso; + if (delta) { + /* Kernel was relocated at boot time */ + pos->start -= delta; + pos->end -= delta; + } + if (count == 0) { curr_map = map; goto filter_symbol; @@ -721,6 +727,10 @@ static int dso__split_kallsyms(struct dso *dso, struct map *map, curr_map->map_ip = curr_map->unmap_ip = identity__map_ip; map_groups__insert(kmaps, curr_map); ++kernel_range; + } else if (delta) { + /* Kernel was relocated at boot time */ + pos->start -= delta; + pos->end -= delta; } filter_symbol: if (filter && filter(curr_map, pos)) { @@ -1130,15 +1140,41 @@ out_err: return -EINVAL; } +/* + * If the kernel is relocated at boot time, kallsyms won't match. Compute the + * delta based on the relocation reference symbol. + */ +static int kallsyms__delta(struct map *map, const char *filename, u64 *delta) +{ + struct kmap *kmap = map__kmap(map); + u64 addr; + + if (!kmap->ref_reloc_sym || !kmap->ref_reloc_sym->name) + return 0; + + addr = kallsyms__get_function_start(filename, + kmap->ref_reloc_sym->name); + if (!addr) + return -1; + + *delta = addr - kmap->ref_reloc_sym->addr; + return 0; +} + int dso__load_kallsyms(struct dso *dso, const char *filename, struct map *map, symbol_filter_t filter) { + u64 delta = 0; + if (symbol__restricted_filename(filename, "/proc/kallsyms")) return -1; if (dso__load_all_kallsyms(dso, filename, map) < 0) return -1; + if (kallsyms__delta(map, filename, &delta)) + return -1; + symbols__fixup_duplicate(&dso->symbols[map->type]); symbols__fixup_end(&dso->symbols[map->type]); @@ -1150,7 +1186,7 @@ int dso__load_kallsyms(struct dso *dso, const char *filename, if (!dso__load_kcore(dso, map, filename)) return dso__split_kallsyms_for_kcore(dso, map, filter); else - return dso__split_kallsyms(dso, map, filter); + return dso__split_kallsyms(dso, map, delta, filter); } static int dso__load_perf_map(struct dso *dso, struct map *map,