From: Peter Zijlstra <peterz@xxxxxxxxxxxxx> commit 50e7b4a1a1b264fc7df0698f2defb93cadf19a7b upstream. When the .altinstr_replacement is a retpoline, skip the alternative. We already special case retpolines anyway. Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Reviewed-by: Miroslav Benes <mbenes@xxxxxxx> Link: https://lkml.kernel.org/r/20210326151300.259429287@xxxxxxxxxxxxx Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- tools/objtool/special.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) --- a/tools/objtool/special.c +++ b/tools/objtool/special.c @@ -104,6 +104,14 @@ static int get_alt_entry(struct elf *elf return -1; } + /* + * Skip retpoline .altinstr_replacement... we already rewrite the + * instructions for retpolines anyway, see arch_is_retpoline() + * usage in add_{call,jump}_destinations(). + */ + if (arch_is_retpoline(new_reloc->sym)) + return 1; + alt->new_sec = new_reloc->sym->sec; alt->new_off = (unsigned int)new_reloc->addend; @@ -152,7 +160,9 @@ int special_get_alts(struct elf *elf, st memset(alt, 0, sizeof(*alt)); ret = get_alt_entry(elf, entry, sec, idx, alt); - if (ret) + if (ret > 0) + continue; + if (ret < 0) return ret; list_add_tail(&alt->list, alts);
