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 57A68C433F5 for ; Sat, 29 Jan 2022 14:55:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345931AbiA2Oze (ORCPT ); Sat, 29 Jan 2022 09:55:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58696 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241965AbiA2Oze (ORCPT ); Sat, 29 Jan 2022 09:55:34 -0500 Received: from mail.sf-mail.de (mail.sf-mail.de [IPv6:2a01:4f8:1c17:6fae:616d:6c69:616d:6c69]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 87D0DC061714 for ; Sat, 29 Jan 2022 06:55:33 -0800 (PST) Received: (qmail 2342 invoked from network); 29 Jan 2022 14:54:06 -0000 Received: from p200300cf0746ee0076d435fffeb7be92.dip0.t-ipconnect.de ([2003:cf:746:ee00:76d4:35ff:feb7:be92]:50366 HELO eto.sf-tec.de) (auth=eike@sf-mail.de) by mail.sf-mail.de (Qsmtpd 0.38dev) with (TLS_AES_256_GCM_SHA384 encrypted) ESMTPSA for ; Sat, 29 Jan 2022 15:54:06 +0100 From: Rolf Eike Beer To: linux-parisc@vger.kernel.org, Helge Deller Cc: James Bottomley , John David Anglin , Randolph Chung Subject: Re: [PATCH] parisc: Add initial vDSO support Date: Sat, 29 Jan 2022 15:55:23 +0100 Message-ID: <11912593.O9o76ZdvQC@eto.sf-tec.de> In-Reply-To: <20220129110342.50853-1-deller@gmx.de> References: <20220129110342.50853-1-deller@gmx.de> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart5536966.DvuYhMxLoT"; micalg="pgp-sha1"; protocol="application/pgp-signature" Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org --nextPart5536966.DvuYhMxLoT Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Am Samstag, 29. Januar 2022, 12:03:42 CET schrieb Helge Deller: > Add minimal vDSO support, which provides the signal trampoline helpers, but > none of the userspace syscall helpers like time functions. > > The big benefit of this vDSO implementation is, that we now don't need an > executeable stack any longer. PA-RISC is one of the last architectures where > an executeable stack was needed in oder to implement the signal trampolines > by putting assembly instructions on the stack which then gets executed. > With this implementation the kernel will utilize the assembler statements > in the vDSO page which is mapped into each userspace application instead > and just put the pointers to the signal information on the stack. > By dropping the need for executable stacks we now avoid running into issues > with various applications in Debian which nowadays want non-executable > stacks for security reasons. Additionally, alternative stacks are supported > better as well. > > This code is based on an initial implementation by Randolph Chung from 2006: > https://lore.kernel.org/linux-parisc/4544A34A.6080700@tausq.org/ > > I did the porting and lifted the code to current code base. Dave fixed the > unwind code so that gdb and glibc are able to backtrace through the code. An > additional patch to gdb will be pushed upstream by Dave. There are a few extra newlines in the first few files which you may or may not want to remove. OTOH I would split out the change to mm_context_t into it's own patch, without adding the vdso_base there. This would reduce the overall size of the actual vdso patch and eases review. Eike --nextPart5536966.DvuYhMxLoT Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part. Content-Transfer-Encoding: 7Bit -----BEGIN PGP SIGNATURE----- iF0EABECAB0WIQSaYVDeqwKa3fTXNeNcpIk+abn8TgUCYfVVWwAKCRBcpIk+abn8 Tgt5AJ9qEkRfmbd0FzX1L4pNR3PE8CjqowCfZ26QrpoHKACXNeWykwImMeFBBE0= =oHhe -----END PGP SIGNATURE----- --nextPart5536966.DvuYhMxLoT--