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Thu, 14 Jan 2021 11:49:24 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id D6408868EF for ; Thu, 14 Jan 2021 11:49:24 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id rEuDDN_axmes for ; Thu, 14 Jan 2021 11:49:23 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mail-io1-f43.google.com (mail-io1-f43.google.com [209.85.166.43]) by fraxinus.osuosl.org (Postfix) with ESMTPS id C27E0868E8 for ; Thu, 14 Jan 2021 11:49:23 +0000 (UTC) Received: by mail-io1-f43.google.com with SMTP id q2so8857145iow.13 for ; Thu, 14 Jan 2021 03:49:23 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=4RgehOiYuLwTJG4mx4zEuvbGGm2iliS/pscxK+Ohf1c=; b=nmoccuIjk1QE+JBydiUdujUtfB4NcOz2O/czE29ZNc1ECsw0NFR5Byph4wEBpd6W4H 59+IzLzTxDS4/k+l9OS52zP1xL7/8yWJAXrK8x5tXSJ1Pjqqc5mhpK/HJs8aWzAYg9/Z 6ApEFmp/1ABH6THpb9QU5ShwEtzTBr/QBXloUIXx77jSPoQ0QdCaEBbM9/SiT72GJvYx B489d/iR5bmANQNv8qehwUc/fi3Ag0JPJZlX3o69BXhHAL+YaUaUR9V6ThVW00rjqP6O Cd7r8Vd0chW7NFZkuYoIvtXmDmm5dRKhFBas5mJKBR8EkmaWVkWy1i0RK3d8qGLxAzcV +8Sg== 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=4RgehOiYuLwTJG4mx4zEuvbGGm2iliS/pscxK+Ohf1c=; b=Wa56N7BTm+XXkphcI/ks9bbBDfjAUMdfBMRJtlGDRqAYhoF2zff0UtTA5JS+Zx1ZC8 5DZrRXtnNtm+qJ7fV0yXtPtqaTYBhRc/Rq6Xa6CpJkpZXrS1B9IDQ1Mjpce8XoN5EJOX vLZmqGIeLB84nuvijVs1EtPIDhjyhiwmM+vO6WvH1r/vmsJA5lTq8X7EEMYiWhB11qbE RzX5KMF3EYHm+QTfSIGNImOdyliJgEuANbgJu1Pj1IS2SMqWxspj8HffointSZTwiwDT XlVvDC9aEQo62RC7OADb92Mq10uDQ5yj3WigaU5X3nwK7onAsg7GxJg9ymCd7wgOYnfe cP/w== X-Gm-Message-State: AOAM531a2wmQq/g46UXmKL7BTylmqiOQw1Jh6nqlAebQUHNP8GKZitLK USuarDgSfCxqWvVet0ChUXPqQTARPjDy35U5a1I= X-Google-Smtp-Source: ABdhPJz9K1iiR0Fhwtasx2BLebuPTy24A4jJxisxQ9VGDqlW6xD9PwM2d72QpLEUHqzCKDCO6/AD5ZinLIcmzsVeLeY= X-Received: by 2002:a6b:8b84:: with SMTP id n126mr4020253iod.189.1610624963095; Thu, 14 Jan 2021 03:49:23 -0800 (PST) MIME-Version: 1.0 References: <20210112115421.GB13086@zn.tnic> <20210112194625.4181814-1-ndesaulniers@google.com> <20210112210154.GI4646@sirena.org.uk> In-Reply-To: <20210112210154.GI4646@sirena.org.uk> From: Lukas Bulwahn Date: Thu, 14 Jan 2021 12:49:20 +0100 Message-ID: To: Dwaipayan Ray , Aditya Srivastava Content-Type: multipart/mixed; boundary="000000000000cac82a05b8dad8b3" Cc: Joe Perches , linux-kernel-mentees@lists.linuxfoundation.org Subject: [Linux-kernel-mentees] Fwd: [PATCH v4] x86/entry: emit a symbol for register restoring thunk X-BeenThere: linux-kernel-mentees@lists.linuxfoundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-kernel-mentees-bounces@lists.linuxfoundation.org Sender: "Linux-kernel-mentees" --000000000000cac82a05b8dad8b3 Content-Type: text/plain; charset="UTF-8" Dwaipayan and Aditya, here is another candidate for a checkpatch rule. Lukas ---------- Forwarded message --------- From: Mark Brown Date: Tue, Jan 12, 2021 at 10:02 PM Subject: Re: [PATCH v4] x86/entry: emit a symbol for register restoring thunk To: Nick Desaulniers Cc: Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Fangrui Song , Arnd Bergmann , Josh Poimboeuf , Jonathan Corbet , , H. Peter Anvin , Nathan Chancellor , Miguel Ojeda , Jiri Slaby , Joe Perches , , , On Tue, Jan 12, 2021 at 11:46:24AM -0800, Nick Desaulniers wrote: This: > when building with LLVM_IAS=1 (Clang's integrated assembler). Josh > notes: > So basically, you can use an .L symbol *inside* a function or a code > segment, you just can't use the .L symbol to contain the code using a > SYM_*_START/END annotation pair. is a stronger statement than this: > + Developers should avoid using local symbol names that are prefixed with > + ``.L``, as this has special meaning for the assembler; a symbol entry will > + not be emitted into the symbol table. This can prevent ``objtool`` from > + generating correct unwind info. Symbols with STB_LOCAL binding may still be > + used, and ``.L`` prefixed local symbol names are still generally useable > + within a function, but ``.L`` prefixed local symbol names should not be used > + to denote the beginning or end of code regions via > + ``SYM_CODE_START_LOCAL``/``SYM_CODE_END``. and seems more what I'd expect - SYM_FUNC* is also affected for example. Even though other usages are probably not very likely it seems better to keep the stronger statement in case someone comes up with one, and to stop anyone spending time wondering why only SYM_CODE_START_LOCAL is affected. This also looks like a good candiate for a checkpatch rule, but that can be done separately of course. -- You received this message because you are subscribed to the Google Groups "Clang Built Linux" group. To unsubscribe from this group and stop receiving emails from it, send an email to clang-built-linux+unsubscribe@googlegroups.com. 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