Messages in this thread Patch in this message | | | From | Josh Poimboeuf <> | Subject | [PATCH 1/3] objtool: Detect jumps to retpoline thunks | Date | Wed, 10 Jan 2018 19:48:46 -0600 |
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A direct jump to a retpoline thunk is really an indirect jump in disguise. Change the objtool instruction type accordingly.
Objtool needs to know where indirect branches are so it can detect switch statement jump tables.
This fixes a bunch of warnings with CONFIG_RETPOLINE like:
arch/x86/events/intel/uncore_nhmex.o: warning: objtool: nhmex_rbox_msr_enable_event()+0x44: sibling call from callable instruction with modified stack frame kernel/signal.o: warning: objtool: copy_siginfo_to_user()+0x91: sibling call from callable instruction with modified stack frame ...
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> --- tools/objtool/check.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 9b341584eb1b..de053fb7049b 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -456,6 +456,13 @@ static int add_jump_destinations(struct objtool_file *file) } else if (rela->sym->sec->idx) { dest_sec = rela->sym->sec; dest_off = rela->sym->sym.st_value + rela->addend + 4; + } else if (strstr(rela->sym->name, "_indirect_thunk_")) { + /* + * Retpoline jumps are really dynamic jumps in + * disguise, so convert them accordingly. + */ + insn->type = INSN_JUMP_DYNAMIC; + continue; } else { /* sibling call */ insn->jump_dest = 0; -- 2.14.3
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