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objtool: Re-add UNWIND_HINT_{SAVE_RESTORE}

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commit 8faea26e611189e933ea2281975ff4dc7c1106b6 upstream.

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  c536ed2fff ("objtool: Remove SAVE/RESTORE hints")

removed the save/restore unwind hints because they were no longer
needed. Now they're going to be needed again so re-add them.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Josh Poimboeuf
2022-06-24 12:52:40 +02:00
committed by Greg Kroah-Hartman
parent 1dbefa5772
commit df93717a32
5 changed files with 59 additions and 6 deletions
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40
tools/objtool/check.c
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@@ -1752,6 +1752,17 @@ static int read_unwind_hints(struct objtool_file *file)
insn->hint = true;
if (hint->type == UNWIND_HINT_TYPE_SAVE) {
insn->hint = false;
insn->save = true;
continue;
}
if (hint->type == UNWIND_HINT_TYPE_RESTORE) {
insn->restore = true;
continue;
}
if (hint->type == UNWIND_HINT_TYPE_REGS_PARTIAL) {
struct symbol *sym = find_symbol_by_offset(insn->sec, insn->offset);
@@ -2847,6 +2858,35 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
state.instr += insn->instr;
if (insn->hint) {
if (insn->restore) {
struct instruction *save_insn, *i;
i = insn;
save_insn = NULL;
sym_for_each_insn_continue_reverse(file, func, i) {
if (i->save) {
save_insn = i;
break;
}
}
if (!save_insn) {
WARN_FUNC("no corresponding CFI save for CFI restore",
sec, insn->offset);
return 1;
}
if (!save_insn->visited) {
WARN_FUNC("objtool isn't smart enough to handle this CFI save/restore combo",
sec, insn->offset);
return 1;
}
insn->cfi = save_insn->cfi;
nr_cfi_reused++;
}
state.cfi = *insn->cfi;
} else {
/* XXX track if we actually changed state.cfi */