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 X-Spam-Level: X-Spam-Status: No, score=-3.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2BB37C2BB55 for ; Thu, 16 Apr 2020 15:16:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EFCF021D7E for ; Thu, 16 Apr 2020 15:16:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="REe17TcB" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2395002AbgDPPQE (ORCPT ); Thu, 16 Apr 2020 11:16:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43692 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S2395072AbgDPPMS (ORCPT ); Thu, 16 Apr 2020 11:12:18 -0400 Received: from merlin.infradead.org (unknown [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4287EC0610D5 for ; Thu, 16 Apr 2020 08:12:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-Id:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=9MwTIMpdaC4VygWnq1XRJh2I8O/EbbREN7voJhdd838=; b=REe17TcBlezyGYkTFxpl06sEVD COBJ1rTV/OvT+Av5oNHPDbrbn3FC5ZrffRNxo6E1Ro7YSTubSgsPEStPA6nzlG0nJJd5HbIicXyOR FKQnqPMqoVGIrelhqBR4E2r9hwVPiT0qZAjOvcSnT46InCkkyvmwLrsW3i6YGzjpPDR+Y50ad4n5Q brxNokmHtiMV8T9qUOeDZHMeHUBsRPaflrmKRIyiIrfeoubcGtL8xYCJDNF2AfmKap/BiLYHosdzy MPfGJLLTE3EFskGVgxYLaQnjMuLPk1fNzZC2dIN0OZUOIOJG6KYTanYswkUhXu6xd+0rcppp0LgdY BCq2yWMw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jP6BH-00046c-L6; Thu, 16 Apr 2020 15:11:55 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 235A63071D5; Thu, 16 Apr 2020 17:11:54 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 01F952B0DE4BC; Thu, 16 Apr 2020 17:11:54 +0200 (CEST) Message-Id: <20200416151024.825863887@infradead.org> User-Agent: quilt/0.65 Date: Thu, 16 Apr 2020 17:07:54 +0200 From: Peter Zijlstra To: jpoimboe@redhat.com, alexandre.chartre@oracle.com Cc: linux-kernel@vger.kernel.org, jthierry@redhat.com, tglx@linutronix.de, x86@kernel.org, peterz@infradead.org Subject: [RFC][PATCH 2/7] objtool: UNWIND_HINT_RET_OFFSET should not check registers References: <20200416150752.569029800@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Alexandre Chartre UNWIND_HINT_RET_OFFSET will adjust a modified stack. However if a callee-saved register was pushed on the stack then the stack frame will still appear modified. So stop checking registers when UNWIND_HINT_RET_OFFSET is used. Signed-off-by: Alexandre Chartre Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20200407073142.20659-3-alexandre.chartre@oracle.com --- tools/objtool/check.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1513,6 +1513,14 @@ static bool has_modified_stack_frame(str if (cfi->stack_size != initial_func_cfi.cfa.offset + ret_offset) return true; + /* + * If there is a ret offset hint then don't check registers + * because a callee-saved register might have been pushed on + * the stack. + */ + if (ret_offset) + return false; + for (i = 0; i < CFI_NUM_REGS; i++) { if (cfi->regs[i].base != initial_func_cfi.regs[i].base || cfi->regs[i].offset != initial_func_cfi.regs[i].offset)