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=-9.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 CCF4BC43463 for ; Fri, 18 Sep 2020 13:44:28 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1DC6720878 for ; Fri, 18 Sep 2020 13:44:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1DC6720878 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zeniv.linux.org.uk Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4BtFS83q7dzDq8w for ; Fri, 18 Sep 2020 23:44:24 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=ftp.linux.org.uk (client-ip=2002:c35c:fd02::1; helo=zeniv.linux.org.uk; envelope-from=viro@ftp.linux.org.uk; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=zeniv.linux.org.uk Received: from ZenIV.linux.org.uk (zeniv.linux.org.uk [IPv6:2002:c35c:fd02::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4BtFMq4YT6zDqCT for ; Fri, 18 Sep 2020 23:40:37 +1000 (AEST) Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kJGcW-0014PO-Gq; Fri, 18 Sep 2020 13:40:12 +0000 Date: Fri, 18 Sep 2020 14:40:12 +0100 From: Al Viro To: Christoph Hellwig Subject: Re: [PATCH 1/9] kernel: add a PF_FORCE_COMPAT flag Message-ID: <20200918134012.GY3421308@ZenIV.linux.org.uk> References: <20200918124533.3487701-1-hch@lst.de> <20200918124533.3487701-2-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200918124533.3487701-2-hch@lst.de> X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-aio@kvack.org, linux-mips@vger.kernel.org, David Howells , linux-mm@kvack.org, keyrings@vger.kernel.org, sparclinux@vger.kernel.org, linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, x86@kernel.org, Arnd Bergmann , linux-block@vger.kernel.org, io-uring@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Jens Axboe , linux-parisc@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Fri, Sep 18, 2020 at 02:45:25PM +0200, Christoph Hellwig wrote: > Add a flag to force processing a syscall as a compat syscall. This is > required so that in_compat_syscall() works for I/O submitted by io_uring > helper threads on behalf of compat syscalls. > > Signed-off-by: Christoph Hellwig > --- > arch/sparc/include/asm/compat.h | 3 ++- > arch/x86/include/asm/compat.h | 2 +- > fs/io_uring.c | 9 +++++++++ > include/linux/compat.h | 5 ++++- > include/linux/sched.h | 1 + > 5 files changed, 17 insertions(+), 3 deletions(-) > > diff --git a/arch/sparc/include/asm/compat.h b/arch/sparc/include/asm/compat.h > index 40a267b3bd5208..fee6c51d36e869 100644 > --- a/arch/sparc/include/asm/compat.h > +++ b/arch/sparc/include/asm/compat.h > @@ -211,7 +211,8 @@ static inline int is_compat_task(void) > static inline bool in_compat_syscall(void) > { > /* Vector 0x110 is LINUX_32BIT_SYSCALL_TRAP */ > - return pt_regs_trap_type(current_pt_regs()) == 0x110; > + return pt_regs_trap_type(current_pt_regs()) == 0x110 || > + (current->flags & PF_FORCE_COMPAT); Can't say I like that approach ;-/ Reasoning about the behaviour is much harder when it's controlled like that - witness set_fs() shite...