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Subject[PATCH 2/3] objtool: check: Ignore unreachable fake jumps
Date
It is possible for alternative code to unconditionally jump out of the
alternative region. In such a case, if a fake jump is added at the end
of the alternative instructions, the fake jump will never be reached.
Since the fake jump is just a mean to make sure code validation does not
go beyond the set of alternatives, reaching it is not a requirement.

Signed-off-by: Julien Thierry <jthierry@redhat.com>
---
tools/objtool/check.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index fd2edab8e672..cd7c6698d316 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2648,6 +2648,9 @@ static bool ignore_unreachable_insn(struct instruction *insn)
!strcmp(insn->sec->name, ".altinstr_aux"))
return true;

+ if (insn->type == INSN_JUMP_UNCONDITIONAL && insn->offset == FAKE_JUMP_OFFSET)
+ return true;
+
if (!insn->func)
return false;

--
2.21.3
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