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=-3.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham 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 06A20C43381 for ; Mon, 18 Mar 2019 15:53:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C9B0A20880 for ; Mon, 18 Mar 2019 15:53:15 +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="MimfWGqG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727878AbfCRPxO (ORCPT ); Mon, 18 Mar 2019 11:53:14 -0400 Received: from merlin.infradead.org ([205.233.59.134]:58810 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727797AbfCRPxH (ORCPT ); Mon, 18 Mar 2019 11:53:07 -0400 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:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=7T84Lnlv66T1X6jWOL4vr/4eoU1srD1fxx4tDzOyoqs=; b=MimfWGqGnZJsJt0Pt+rYledetz UVkHK51Vvw5PY6yH1uE371ggYbEsjF7fjEKEzG9HHoIMyLFsZG2UaDAr8YwLgPVGQW07COVgWjhLY RwoU4kyA67z/QaP7lYMVdfQVUYt/qXwiRRkKxYmkP+EY0aX34Uqsy13lQXjL/03bZk+48b+mfz6hQ e3qHF80Xh5vFjAZaslkctaRBUdwDftmlG+b+eETWrFfXYHUH1wW5YuU+HTYLUtKd6y9Ha5sY4CKQC T8jHbuer57bsVgd3evENJQwj9SGlkazMN4110qSkTykmWG/MM2V9nEk/384nvCPIL/gyL9laFMIOf ynYSiqzA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1h5uZ7-0005Uw-GB; Mon, 18 Mar 2019 15:52:41 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id A789B25E45D72; Mon, 18 Mar 2019 16:52:38 +0100 (CET) Message-Id: <20190318155140.628311202@infradead.org> User-Agent: quilt/0.65 Date: Mon, 18 Mar 2019 16:38:48 +0100 From: Peter Zijlstra To: torvalds@linux-foundation.org, tglx@linutronix.de, hpa@zytor.com, julien.thierry@arm.com, will.deacon@arm.com, luto@amacapital.net, mingo@kernel.org, catalin.marinas@arm.com, james.morse@arm.com, valentin.schneider@arm.com, brgerst@gmail.com, jpoimboe@redhat.com, luto@kernel.org, bp@alien8.de, dvlasenk@redhat.com Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, dvyukov@google.com, rostedt@goodmis.org, andrew.cooper3@citrix.com, Juergen Gross Subject: [PATCH 08/25] x86/uaccess,xen: Suppress SMAP warnings References: <20190318153840.906404905@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 drivers/xen/privcmd.o: warning: objtool: privcmd_ioctl()+0x1414: call to hypercall_page() with UACCESS enabled Some Xen hypercalls allow parameter buffers in user land, so they need to set AC=1. Avoid the warning for those cases. Cc: andrew.cooper3@citrix.com Reviewed-by: Juergen Gross Signed-off-by: Peter Zijlstra (Intel) --- arch/x86/include/asm/xen/hypercall.h | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) --- a/arch/x86/include/asm/xen/hypercall.h +++ b/arch/x86/include/asm/xen/hypercall.h @@ -214,6 +214,22 @@ xen_single_call(unsigned int call, return (long)__res; } +static __always_inline void __xen_stac(void) +{ + /* + * Suppress objtool seeing the STAC/CLAC and getting confused about it + * calling random code with AC=1. + */ + asm volatile(ANNOTATE_IGNORE_ALTERNATIVE + ASM_STAC ::: "memory", "flags"); +} + +static __always_inline void __xen_clac(void) +{ + asm volatile(ANNOTATE_IGNORE_ALTERNATIVE + ASM_CLAC ::: "memory", "flags"); +} + static inline long privcmd_call(unsigned int call, unsigned long a1, unsigned long a2, @@ -222,9 +238,9 @@ privcmd_call(unsigned int call, { long res; - stac(); + __xen_stac(); res = xen_single_call(call, a1, a2, a3, a4, a5); - clac(); + __xen_clac(); return res; } @@ -421,9 +437,9 @@ HYPERVISOR_dm_op( domid_t dom, unsigned int nr_bufs, struct xen_dm_op_buf *bufs) { int ret; - stac(); + __xen_stac(); ret = _hypercall3(int, dm_op, dom, nr_bufs, bufs); - clac(); + __xen_clac(); return ret; }