From patchwork Thu Oct 12 17:50:36 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: tip-bot2 for Thomas Gleixner X-Patchwork-Id: 152096 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:612c:2908:b0:403:3b70:6f57 with SMTP id ib8csp1402688vqb; Thu, 12 Oct 2023 10:51:08 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHk9gIl3cJkb6gsUPr9DYKpROWT9UUgr8BfTkQGac5mURHGmCSaVP7h1Zd0QSI8jxQnNoEI X-Received: by 2002:a05:6a20:4407:b0:133:6e3d:68cd with SMTP id ce7-20020a056a20440700b001336e3d68cdmr33831987pzb.3.1697133068388; Thu, 12 Oct 2023 10:51:08 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1697133068; cv=none; d=google.com; s=arc-20160816; b=WzloL8lXVGQ6ROakVYBKwWzXK8wIVQedSNu8Hr3zo7f3EH/17lHYoVhHWwOcxRKSp/ MuZumLkIt2yaIENbOqQfXzOzmNFq/F+y9TASSrN5SONO8dLg1A3BAZ9XXHuT2+2jwP6g IkZPb8Zle/ny5/RkbZ19PruP1szAB4MkBFw3HUW95kOw9i7Bz5NaPioawO58mnHxr48e EXj6CLbIpe/pJDGZyX8Fq0SuyzsB7m2/xor8zd3B6Y9/gD5ctqfUsEKNs7E3FqsZORZZ gu5nT4pGQmCw4YsVL8TlQJId3E4SQPh9zg3FH4yfyLnMnowYHbw3u8rM1Ac0900kbPxE XRUQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:robot-unsubscribe :robot-id:message-id:mime-version:references:in-reply-to:cc:subject :to:reply-to:sender:from:dkim-signature:dkim-signature:date; bh=ZsTxEDhbaIphlw0jzXT8l5TRWd+hq/UI1Z+VXihjkW0=; fh=+5woaQgYspvXXFHhSOaDsxVsOyMe8eYUj6fvdNOs7iE=; b=IMNjRQKRo0Ck1GJ2aWzrYcIUVrg+aT/PI9S1BAEJjn0SC+rlGQA10axj8TvR+ICAKJ WxzRuXSb5MT6fXQihjc7gUJDtqUALwxGHu0HrJ0gJjDvtI6Xwjz3NPOkNtVTWGf4kjQD UvkkCg462hYiq7NGcMP7gaiCSzKd1jE9M8OUUlJoJlqMhuPnEaM39lyoTZLaI75Qtsul 0UrinYmqojxSg1glzpCN/8tgPwkw7UL1cFjrJunkF5RqaXEexmNL0kUgcxIEQTN10j+r YZr5kOooOza5XTzLh0KQIcrw888b9TwRh837QT3wjte4hJCOU5/YSMDSVHvGiYQSthrk ha5g== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linutronix.de header.s=2020 header.b=2Jtdq7HS; dkim=neutral (no key) header.i=@linutronix.de header.s=2020e header.b=RBYd5Ssv; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.32 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=linutronix.de Received: from agentk.vger.email (agentk.vger.email. [23.128.96.32]) by mx.google.com with ESMTPS id a11-20020a170902ee8b00b001c9ebe878d7si427376pld.109.2023.10.12.10.51.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Oct 2023 10:51:07 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.32 as permitted sender) client-ip=23.128.96.32; Authentication-Results: mx.google.com; dkim=pass header.i=@linutronix.de header.s=2020 header.b=2Jtdq7HS; dkim=neutral (no key) header.i=@linutronix.de header.s=2020e header.b=RBYd5Ssv; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.32 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=linutronix.de Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by agentk.vger.email (Postfix) with ESMTP id 5D3AD819F987; Thu, 12 Oct 2023 10:51:05 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at agentk.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1441878AbjJLRus (ORCPT + 19 others); Thu, 12 Oct 2023 13:50:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49786 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1379676AbjJLRuk (ORCPT ); Thu, 12 Oct 2023 13:50:40 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3A7F7CF; Thu, 12 Oct 2023 10:50:39 -0700 (PDT) Date: Thu, 12 Oct 2023 17:50:36 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1697133037; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ZsTxEDhbaIphlw0jzXT8l5TRWd+hq/UI1Z+VXihjkW0=; b=2Jtdq7HSABAAUZk6N8frXHwXVnTlsX3gqQxpS0nAf6Lc3YCyHYEkcsTQR3LcSee0zewOhk 3TcUaIJQsUlu1Cu7PXzYCd1/m43e8vcObJVwbVo7EB4quD1BMqEb3c2SV7mSEXH9ADWoNd 5t/u/PpbpBsOXQy4PbOODLuxI6/63sLl8B3P2Pfre7puGX+zEX8kpAFUw8FzIEHkdumJwM 3SlALlLqncsMKg07biAy2fkgDjscqVcIiDq4+ydjkMonD0z5d6pJBgOJMRNwGtewmy3eOZ BwLTCQFtIiR3o9OwVIxWuDtgJZrPtbdl0wtP1wv4MXwKdc5rk/CgF2gwXFN6xw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1697133037; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ZsTxEDhbaIphlw0jzXT8l5TRWd+hq/UI1Z+VXihjkW0=; b=RBYd5SsvwAcFbUISugZ6tbNxK7+D/f393O+/niDm+iafq8yfyJ+9uKRSGmufSQR1cvdMEM 9zbw2AWmltcA+CDA== From: "tip-bot2 for Josh Poimboeuf" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/bugs] objtool: Fix return thunk patching in retpolines Cc: David Kaplan , Josh Poimboeuf , Ingo Molnar , "Peter Zijlstra (Intel)" , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20231012024737.eg5phclogp67ik6x@treble> References: <20231012024737.eg5phclogp67ik6x@treble> MIME-Version: 1.0 Message-ID: <169713303673.3135.1345736146578099050.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails X-Spam-Status: No, score=-0.8 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on agentk.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (agentk.vger.email [0.0.0.0]); Thu, 12 Oct 2023 10:51:05 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1779516178032927751 X-GMAIL-MSGID: 1779573003249817406 The following commit has been merged into the x86/bugs branch of tip: Commit-ID: eadbe6606a85610c63e6cfaa9257dc7e3bbb901c Gitweb: https://git.kernel.org/tip/eadbe6606a85610c63e6cfaa9257dc7e3bbb901c Author: Josh Poimboeuf AuthorDate: Wed, 11 Oct 2023 19:47:37 -07:00 Committer: Ingo Molnar CommitterDate: Thu, 12 Oct 2023 19:43:51 +02:00 objtool: Fix return thunk patching in retpolines With CONFIG_RETHUNK enabled, the compiler replaces every RET with a tail call to a return thunk ('JMP __x86_return_thunk'). Objtool annotates all such return sites so they can be patched during boot by apply_returns(). The implementation of __x86_return_thunk() is just a bare RET. It's only meant to be used temporarily until apply_returns() patches all return sites with either a JMP to another return thunk or an actual RET. The following commit: e92626af3234 ("x86/retpoline: Remove .text..__x86.return_thunk section") broke objtool's detection of return sites in retpolines. Since retpolines and return thunks are now in the same section, the compiler no longer uses relocations for the intra-section jumps between the retpolines and the return thunk, causing objtool to overlook them. As a result, none of the retpolines' return sites get patched. Each one stays at 'JMP __x86_return_thunk', effectively a bare RET. Fix it by teaching objtool to detect when a non-relocated jump target is a return thunk (or retpoline). Fixes: e92626af3234 ("x86/retpoline: Remove .text..__x86.return_thunk section") Reported-by: David Kaplan Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20231012024737.eg5phclogp67ik6x@treble --- tools/objtool/check.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/tools/objtool/check.c b/tools/objtool/check.c index e308d1b..e94756e 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1611,6 +1611,22 @@ static int add_jump_destinations(struct objtool_file *file) } /* + * An intra-TU jump in retpoline.o might not have a relocation + * for its jump dest, in which case the above + * add_{retpoline,return}_call() didn't happen. + */ + if (jump_dest->sym && jump_dest->offset == jump_dest->sym->offset) { + if (jump_dest->sym->retpoline_thunk) { + add_retpoline_call(file, insn); + continue; + } + if (jump_dest->sym->return_thunk) { + add_return_call(file, insn, true); + continue; + } + } + + /* * Cross-function jump. */ if (insn_func(insn) && insn_func(jump_dest) &&