Em Wed, Jan 29, 2014 at 04:14:43PM +0200, Adrian Hunter escreveu:
> 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.
Don't we have map->reloc? Can't we use it here, i.e. be consistent and
have the unrelocated address + the relocation, and then, when using
map->{map,unmap} take that into account, as you did to the objdump
variants, no?
I applied the others, testing now.
- Arnaldo
> Signed-off-by: Adrian Hunter <adrian.hun...@intel.com>
> ---
> 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 4ac1f87..a9d758a 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,
> --
> 1.7.11.7
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