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=-5.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 AE728C49EA5 for ; Wed, 23 Jun 2021 00:21:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9D8C161374 for ; Wed, 23 Jun 2021 00:21:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230028AbhFWAYC (ORCPT ); Tue, 22 Jun 2021 20:24:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229747AbhFWAX7 (ORCPT ); Tue, 22 Jun 2021 20:23:59 -0400 Received: from mail-pf1-x432.google.com (mail-pf1-x432.google.com [IPv6:2607:f8b0:4864:20::432]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 78D6EC061574 for ; Tue, 22 Jun 2021 17:21:43 -0700 (PDT) Received: by mail-pf1-x432.google.com with SMTP id t32so887246pfg.2 for ; Tue, 22 Jun 2021 17:21:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=bcpFSddWrPJ8W2Ub9oAqINluFXniubX2BEcya4POfK0=; b=gwBNeemJ5unhLEX+su0amWIFj9gAuivmQkyRdhLSVdn7mOpedbuU9suRoeDTbHP6Sw 2o4aAmEQGzGyzh6dgeeKuVoJ/dcSBTRgpQWYmvLEA6WrQwVjnaxRYdM0QVrv49e8BkIm RUTVq4SCvjX+dHU1G9vheOoC+7Sjq7HPl+LTV6oX07oC5rjOXDrq0LB3V9rQVUjPReUN gbWRhJKznlKfVsonI7xnCBeTvm1LPOGc1EeUiakyQadpUvCETQCD4TtnjUW3S6fv902J q11Hg7hwHfIikq06WmCxf+KYppmoag7Ogof8Z6j1489hE6Soa52gcAVUrkWgB3YfOwKM C8iA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=bcpFSddWrPJ8W2Ub9oAqINluFXniubX2BEcya4POfK0=; b=I2LFI37W6aCeyHyE8TuKz/11N8ICsMXx3sJX7W3aUABf5g1IA0F0dScpO9fyfUUgmY ubhDTnt7iS2d5E1J0cWJ42S/7AD2SZCYZGGlncy/Oep2L1djdGOShLTNCdHn1lwmmXtn fj+zlpnpSfC+dMvL935a37V9At33BFyLxRx7iqQCFi+mNOiOLaOZ4UEp7p0qbiXi9eR9 0PGQzvoU1R6G24el1JJhngA6xggzA+oVvt1kIiQST/KqDccXLM1/3/Y19eHmcd/z5gjQ ohHvZVmdH60Im7wkk3QeblCd2CUAOOfEoUBhIBSlkjpJd9ThfjdkszbXrBLv7rHwbn4Y kfug== X-Gm-Message-State: AOAM532YFbZ6J/WE9fpFBkenq0aBb4x7WBDz+Dl5zKEVKtm/JtzRxWvH vxuZ0x86nRYixJnoyjgfBlI= X-Google-Smtp-Source: ABdhPJxfZzuKldyvpa4kU6lsJEvzGiSk/v0sOcODc77n3F5Kx2fnf3bGfzoDYoam0JBEdNlktunW2Q== X-Received: by 2002:a63:4002:: with SMTP id n2mr1192108pga.124.1624407703055; Tue, 22 Jun 2021 17:21:43 -0700 (PDT) Received: from xplor.waratah.dyndns.org (222-152-189-137-fibre.sparkbb.co.nz. [222.152.189.137]) by smtp.gmail.com with ESMTPSA id f17sm20768764pgm.37.2021.06.22.17.21.42 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Tue, 22 Jun 2021 17:21:42 -0700 (PDT) Received: by xplor.waratah.dyndns.org (Postfix, from userid 1000) id 84C4C3603D8; Wed, 23 Jun 2021 12:21:38 +1200 (NZST) From: Michael Schmitz To: geert@linux-m68k.org, linux-arch@vger.kernel.org, linux-m68k@lists.linux-m68k.org Cc: ebiederm@xmission.com, torvalds@linux-foundation.org, schwab@linux-m68k.org Subject: [PATCH v4 0/3] m68k: Improved switch stack handling Date: Wed, 23 Jun 2021 12:21:33 +1200 Message-Id: <1624407696-20180-1-git-send-email-schmitzmic@gmail.com> X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org m68k version of Eric's patch series 'alpha/ptrace: Improved switch_stack handling'. Registers d6, d7, a3-a6 are not saved on the stack by default on every syscall entry by the m68k kernel. A separate switch stack frame is pushed to save those registers as needed. This leaves the majority of syscalls with only a subset of registers on the stack, and access to unsaved registers in those would expose or modify random stack addresses. Patch 1 and 2 add a switch stack for all syscalls that were found to need one to allow ptrace access to all registers outside of syscall entry/exit tracing, as well as kernel worker threads. This ought to protect against accidents. Patch 3 adds safety checks and debug output to m68k get_reg() and put_reg() functions. Any unsafe register access during process tracing will be prevented and reported. Suggestions for optimizations or improvements welcome! Cheers, Michael Link: https://lore.kernel.org/r/<87pmwlek8d.fsf_-_@disp2133>