From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4B22EC433EF for ; Fri, 22 Jul 2022 09:12:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235369AbiGVJMH (ORCPT ); Fri, 22 Jul 2022 05:12:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40624 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233321AbiGVJLX (ORCPT ); Fri, 22 Jul 2022 05:11:23 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 52F6DA9B90; Fri, 22 Jul 2022 02:09:40 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 1FAA7CE28A3; Fri, 22 Jul 2022 09:09:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 059B8C341CF; Fri, 22 Jul 2022 09:09:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1658480975; bh=83KBoNHTObUwYxuqr2Qy7ZLK4DdR4Ff7RsV0XylXjOE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=k0V7v7dLDaALNkwpB0nHcLgcpAG3GXQPz9UwhBZsNN/d+6BZ38dendC5cHCeuj3l5 wzz2z6pP9K++TXY36HZqXO/RBjMlBsHC4p/TpOF234el68jJriKYy7Xmv+NdbGaSKB x8SEv5bnmwvX1pMe8piAx5p8sXFtFL63OZWCIsGE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Peter Zijlstra (Intel)" , Borislav Petkov , Josh Poimboeuf , Thadeu Lima de Souza Cascardo Subject: [PATCH 5.18 15/70] x86/ftrace: Use alternative RET encoding Date: Fri, 22 Jul 2022 11:07:10 +0200 Message-Id: <20220722090651.577053810@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220722090650.665513668@linuxfoundation.org> References: <20220722090650.665513668@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Peter Zijlstra commit 1f001e9da6bbf482311e45e48f53c2bd2179e59c upstream. Use the return thunk in ftrace trampolines, if needed. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov Reviewed-by: Josh Poimboeuf Signed-off-by: Borislav Petkov Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/ftrace.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -303,7 +303,7 @@ union ftrace_op_code_union { } __attribute__((packed)); }; -#define RET_SIZE 1 + IS_ENABLED(CONFIG_SLS) +#define RET_SIZE (IS_ENABLED(CONFIG_RETPOLINE) ? 5 : 1 + IS_ENABLED(CONFIG_SLS)) static unsigned long create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size) @@ -359,7 +359,10 @@ create_trampoline(struct ftrace_ops *ops goto fail; ip = trampoline + size; - memcpy(ip, retq, RET_SIZE); + if (cpu_feature_enabled(X86_FEATURE_RETHUNK)) + __text_gen_insn(ip, JMP32_INSN_OPCODE, ip, &__x86_return_thunk, JMP32_INSN_SIZE); + else + memcpy(ip, retq, sizeof(retq)); /* No need to test direct calls on created trampolines */ if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {