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authorAdrian Hunter <adrian.hunter@intel.com>2023-01-31 15:16:22 +0200
committerArnaldo Carvalho de Melo <acme@redhat.com>2023-02-01 21:51:31 -0300
commit60fbb3e49abe8421b677d5eee32fe7fb27b05e3b (patch)
tree50a633898fb7d4ad59c5922bf09ab032f46aed9b /tools/perf/util/symbol-elf.c
parentb7dbc0be6e4f2a5268d76884d6651e29f95673ea (diff)
perf symbols: Allow for .plt without header
A static executable can have a .plt due to the presence of IFUNCs. In that case the .plt does not have a header. Check for whether there is a header by comparing the number of entries to the number of relocation entries. Reviewed-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Cc: Ian Rogers <irogers@google.com> Cc: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20230131131625.6964-7-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/symbol-elf.c')
-rw-r--r--tools/perf/util/symbol-elf.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index a002fc0bea03..8f7802097c72 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -489,6 +489,7 @@ int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
Elf *elf;
int nr = 0, err = -1;
struct rel_info ri = { .is_rela = false };
+ bool lazy_plt;
elf = ss->elf;
ehdr = ss->ehdr;
@@ -523,8 +524,10 @@ int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
plt_sym->end = plt_sym->start + shdr_plt.sh_size;
/* Use .plt.sec offset */
plt_offset = plt_sec_shdr.sh_offset;
+ lazy_plt = false;
} else {
- plt_offset = shdr_plt.sh_offset + plt_header_size;
+ plt_offset = shdr_plt.sh_offset;
+ lazy_plt = true;
}
scn_dynsym = ss->dynsym;
@@ -577,6 +580,17 @@ int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
ri.is_rela = shdr_rel_plt.sh_type == SHT_RELA;
+ if (lazy_plt) {
+ /*
+ * Assume a .plt with the same number of entries as the number
+ * of relocation entries is not lazy and does not have a header.
+ */
+ if (ri.nr_entries * plt_entry_size == shdr_plt.sh_size)
+ dso__delete_symbol(dso, plt_sym);
+ else
+ plt_offset += plt_header_size;
+ }
+
/*
* x86 doesn't insert IFUNC relocations in .plt order, so sort to get
* back in order.