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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_RED 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 821E2C4320A for ; Sun, 25 Jul 2021 10:05:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 530FC60F26 for ; Sun, 25 Jul 2021 10:05:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230461AbhGYJZI (ORCPT ); Sun, 25 Jul 2021 05:25:08 -0400 Received: from mail-vk1-f172.google.com ([209.85.221.172]:39481 "EHLO mail-vk1-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230370AbhGYJZI (ORCPT ); Sun, 25 Jul 2021 05:25:08 -0400 Received: by mail-vk1-f172.google.com with SMTP id f1so1379263vkk.6 for ; Sun, 25 Jul 2021 03:05:37 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=XHyqWT5T8EnnHCYAwXfDHN6CTdT91ozwfA6Z/DQ/7N8=; b=hyh/Y061JVhYgDZZ5GFHZhIAddProdK+0LmFzgLc5H2/Ekgrjo1GhH6ibR+/+Lvz5Q l/qF6GxNn4KrWMlzpYuPp7jxZcp+iZS10sSPkYAdgbeUzNXwufhTtzmQANKzL4rmBx1f R+9Bt5b8EWHr/BsZ4Xo+765xNXc6HcFy4gSoN18fftBD4w+AR33LcjqFmI9xQYUuL11N Iwtw0EFN7cQffAmZq2tTkD4GDtK81ipwvYvUYJQ21pjQxNYhOjxS92fB+4yxDpnbtykc 0PDPdn4v5UDq4XuJWsno565aVSj/1caVjLyAYQdy0RmRhfwz9IkXGpNgfNx0v0pJEwPg HTaA== X-Gm-Message-State: AOAM532+MV68O5SFCjiDcoEKVRxTHq1ScK8k2FSrLgtUwwQDB0XoHv/U kERyGlQusi33jXLGwHPlHVGd6u6FJdfOB1VxYMY= X-Google-Smtp-Source: ABdhPJzQKq4M8f7Z5qDbOveUgVw3PiuXDpF00/PNMEaRAbyNIAhtUEl8Hf0fNN11BiGeW9PYKobK+69rnZDtrCXfnl8= X-Received: by 2002:ac5:cd9b:: with SMTP id i27mr7805690vka.1.1627207537068; Sun, 25 Jul 2021 03:05:37 -0700 (PDT) MIME-Version: 1.0 References: <1624407696-20180-1-git-send-email-schmitzmic@gmail.com> <1624407696-20180-4-git-send-email-schmitzmic@gmail.com> In-Reply-To: <1624407696-20180-4-git-send-email-schmitzmic@gmail.com> From: Geert Uytterhoeven Date: Sun, 25 Jul 2021 12:05:26 +0200 Message-ID: Subject: Re: [PATCH v4 3/3] m68k: track syscalls being traced with shallow user context stack To: Michael Schmitz Cc: Linux-Arch , linux-m68k , "Eric W. Biederman" , Linus Torvalds , Andreas Schwab Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org Hi Michael, On Wed, Jun 23, 2021 at 2:21 AM Michael Schmitz wrote: > Add 'status' field to thread_info struct to hold syscall trace > status info. > > Set flag bit in thread_info->status at syscall trace entry, clear > flag bit on trace exit. > > Set another flag bit on entering syscall where the full stack > frame has been saved. These flags can be checked whenever a > syscall calls ptrace_stop(). > > Check flag bits in get_reg()/put_reg() and prevent access to > registers that are saved on the switch stack, in case the > syscall did not actually save these registers on the switch > stack. > > Tested on ARAnyM only - boots and survives running strace on a > binary, nothing fancy. > > CC: Eric W. Biederman > CC: Linus Torvalds > CC: Andreas Schwab > Signed-off-by: Michael Schmitz Thanks for your patch! > --- a/arch/m68k/kernel/entry.S > +++ b/arch/m68k/kernel/entry.S > @@ -51,75 +51,115 @@ > > .text > ENTRY(__sys_fork) > + movel %curptr@(TASK_STACK),%a1 > + orb #TIS_SWITCH_STACK, %a1@(TINFO_STATUS+3) This doesn't work on Coldfire: arch/m68k/kernel/entry.S:55: Error: invalid instruction for this architecture; needs 68000 or higher (68000 [68ec000, 68hc000, 68hc001, 68008, 68302, 68306, 68307, 68322, 68356], 68010, 68020 [68k, 68ec020], 68030 [68ec030], 68040 [68ec040], 68060 [68ec060], cpu32 [68330, 68331, 68332, 68333, 68334, 68336, 68340, 68341, 68349, 68360], fidoa [fido]) -- statement `orb #(1<<1),%a1@(16+3)' ignored > SAVE_SWITCH_STACK > jbsr sys_fork > lea %sp@(24),%sp > + movel %curptr@(TASK_STACK),%a1 > + andb #TIS_NO_SWITCH_STACK, %a1@(TINFO_STATUS+3) arch/m68k/kernel/entry.S:60: Error: invalid instruction for this architecture; needs 68000 or higher (68000 [68ec000, 68hc000, 68hc001, 68008, 68302, 68306, 68307, 68322, 68356], 68010, 68020 [68k, 68ec020], 68030 [68ec030], 68040 [68ec040], 68060 [68ec060], cpu32 [68330, 68331, 68332, 68333, 68334, 68336, 68340, 68341, 68349, 68360], fidoa [fido]) -- statement `andb #(~((1<<1))),%a1@(16+3)' ignored > rts Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds