objtool, modules: Discard objtool annotation sections for modules

The '__unreachable' and '__func_stack_frame_non_standard' sections are
only used at compile time.  They're discarded for vmlinux but they
should also be discarded for modules.

Since this is a recurring pattern, prefix the section names with
".discard.".  It's a nice convention and vmlinux.lds.h already discards
such sections.

Also remove the 'a' (allocatable) flag from the __unreachable section
since it doesn't make sense for a discarded section.

Suggested-by: Linus Torvalds <[email protected]>
Signed-off-by: Josh Poimboeuf <[email protected]>
Cc: Jessica Yu <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Fixes: d1091c7fa3 ("objtool: Improve detection of BUG() and other dead ends")
Link: http://lkml.kernel.org/r/20170301180444.lhd53c5tibc4ns77@treble
Signed-off-by: Ingo Molnar <[email protected]>
This commit is contained in:
Josh Poimboeuf 2017-03-01 12:04:44 -06:00 • committed by Ingo Molnar
commit e390f9a968
6 changed files with 10 additions and 8 deletions

View file

@ -339,13 +339,13 @@ static int add_dead_ends(struct objtool_file *file)
struct instruction *insn;
bool found;
sec = find_section_by_name(file->elf, ".rela__unreachable");
sec = find_section_by_name(file->elf, ".rela.discard.unreachable");
if (!sec)
return 0;
list_for_each_entry(rela, &sec->rela_list, list) {
if (rela->sym->type != STT_SECTION) {
WARN("unexpected relocation symbol type in .rela__unreachable");
WARN("unexpected relocation symbol type in %s", sec->name);
return -1;
}
insn = find_insn(file, rela->sym->sec, rela->addend);
@ -1272,7 +1272,7 @@ int cmd_check(int argc, const char **argv)
INIT_LIST_HEAD(&file.insn_list);
hash_init(file.insn_hash);
file.whitelist = find_section_by_name(file.elf, "__func_stack_frame_non_standard");
file.whitelist = find_section_by_name(file.elf, ".discard.func_stack_frame_non_standard");
file.rodata = find_section_by_name(file.elf, ".rodata");
file.ignore_unreachables = false;
file.c_file = find_section_by_name(file.elf, ".comment");