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=-8.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 EF6F0CA9EA0 for ; Fri, 25 Oct 2019 20:51:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BCBD52054F for ; Fri, 25 Oct 2019 20:51:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="OMpIHy66" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726668AbfJYUvf (ORCPT ); Fri, 25 Oct 2019 16:51:35 -0400 Received: from mail-vs1-f65.google.com ([209.85.217.65]:37019 "EHLO mail-vs1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725801AbfJYUvf (ORCPT ); Fri, 25 Oct 2019 16:51:35 -0400 Received: by mail-vs1-f65.google.com with SMTP id e12so2382169vsr.4 for ; Fri, 25 Oct 2019 13:51:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=SOwCMPM2O4ZOlwd3DBrA7iEvzDojcSJWVcNWTrD2V3A=; b=OMpIHy666PHw9erjn8xDTPpke8xQntbqoetTb755EO9PeDOpXuqP6XhDAI7uUr5fO2 xmVL8gs1k0UTMM90x7YH/5ifo3akIvmtUP3P99Y8UkXss+I/VMnYl83cvTyhYTBE+xXo cZnJNJr5EGcHbCKDOw5qzZmWgscClEDk8K70pc2sU5/7TsNOz3qMBup0ghahhpvfFUWg vkZUy83KnTruoWWThCWKQaNjwulexQFfxNHsd7rgNtxCf3BUJ3Swu+Hls5xYOIdyzbqN pTUp3jauqQWIFYhE31Un5fjVTn41lvbrOA703W64zMOhKqcxNHtTJHVm5pwg8QOK9PnF Ba7w== 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=SOwCMPM2O4ZOlwd3DBrA7iEvzDojcSJWVcNWTrD2V3A=; b=p4APuxsOn/nVopJmYZuvy9VEM/OA2m/t3N69ZFt46ii2Oq8GdH2F4uHTT5GHZFdP8z TQFHm9z5YTUpVzhsa30C9hd3tWF1Nbz5WExBt0K4Wb8j2MKOHs4LU7Z++HPYM8yXG6no ZAkIvxOjwA1LyO3ZFB2/5H1lwZBdwaHavOpkz/UuB8Y9xj2HdK9QB4e5kzAa3GpOIR+w 9wXgNHMeESx/TVtdmzFpN1/Yie3hWqj3eKYVsPQqG3y84Y1IHG4QTIUMQcXPPJBtHKZw oXF8gaK5uEpKspvKkGWsZx5TgdluVCYlewCgR9i7RjH2GxCvkuqW0/L7hkTEBqFpQkim Dpjw== X-Gm-Message-State: APjAAAVx433krlqdlNJ0JTJW4UaRmdx4LGUlkpMxF+VAQCQ8wevrfQAZ /Ke+rDD2E0Lhhec6uoAfem43yk+B2W1XNG6lX+otNg== X-Google-Smtp-Source: APXvYqwitHy/uW9BgFO85xlL31gu4CkfssJm5Y58pk3pu/OFECEhzo8ZcmTg1xeRhUyxbxF5+qEX2qRHXCg/5F+6CB8= X-Received: by 2002:a67:ed8b:: with SMTP id d11mr3107850vsp.104.1572036693631; Fri, 25 Oct 2019 13:51:33 -0700 (PDT) MIME-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20191024225132.13410-1-samitolvanen@google.com> <20191024225132.13410-6-samitolvanen@google.com> In-Reply-To: From: Sami Tolvanen Date: Fri, 25 Oct 2019 13:51:22 -0700 Message-ID: Subject: Re: [PATCH v2 05/17] add support for Clang's Shadow Call Stack (SCS) To: Nick Desaulniers Cc: Will Deacon , Catalin Marinas , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel , Dave Martin , Kees Cook , Laura Abbott , Mark Rutland , Jann Horn , Miguel Ojeda , Masahiro Yamada , clang-built-linux , Kernel Hardening , Linux ARM , LKML Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 25, 2019 at 9:22 AM Nick Desaulniers wrote: > > +static void scs_free(void *s) > > +{ > > + int i; > > + > > + for (i = 0; i < SCS_CACHE_SIZE; i++) { > > + if (this_cpu_cmpxchg(scs_cache[i], 0, s) != 0) > > + continue; > > + > > + return; > > + } > > prefer: > > for ...: > if foo() == 0: > return > > to: > > for ...: > if foo() != 0: > continue > return This was essentially copied from free_thread_stack in kernel/fork.c, but I agree, your way is cleaner. I'll change this in the next version. Thanks! Sami 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=-0.7 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_ADSP_CUSTOM_MED,DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 608C2CA9EA0 for ; Fri, 25 Oct 2019 20:51:49 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 28F0521872 for ; Fri, 25 Oct 2019 20:51:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="jlqQEGEX"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=google.com header.i=@google.com header.b="OMpIHy66" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 28F0521872 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:To:Subject:Message-ID:Date:From: In-Reply-To:References:MIME-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=lR5mLwt7NtffLY0OlHJ7MTNvWgmUQcafF2uDqDrc3GU=; b=jlqQEGEXHmZvIb r3cEc0U7T4dF6sMPnzYIgzSaDM2dxXXuYSIBNJ+5YY73gYwgV85Tklh5FqQ4xmsJm9rBsgeD/TTFv m0LQop94Vo34+4h9v2g+YeeV8HJWybFSDcWgjylzZ/9kUOhSXFeobGoPwk1B0doKMLYkBNdoqEfAe pcj8nNjhPqKunKKOGyyGd18E7XyyBNHJ8E2LvtKhTw2XHHRWD9CMrRSLSG4Y2nUVii915IDb+BrqQ U4k432C0O4j5WZCjB6+/l6ZC50v3Y2GdEXGs9POeeJRsziUhgDnlQT0MBGLfsJxArQZbzJ3EaUqdj ZU9sPpuaK4aFc3vGATug==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1iO6Yf-0001O3-Ti; Fri, 25 Oct 2019 20:51:41 +0000 Received: from mail-vs1-xe43.google.com ([2607:f8b0:4864:20::e43]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1iO6Yd-0001NE-4Y for linux-arm-kernel@lists.infradead.org; Fri, 25 Oct 2019 20:51:40 +0000 Received: by mail-vs1-xe43.google.com with SMTP id a143so1548918vsd.9 for ; Fri, 25 Oct 2019 13:51:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=SOwCMPM2O4ZOlwd3DBrA7iEvzDojcSJWVcNWTrD2V3A=; b=OMpIHy666PHw9erjn8xDTPpke8xQntbqoetTb755EO9PeDOpXuqP6XhDAI7uUr5fO2 xmVL8gs1k0UTMM90x7YH/5ifo3akIvmtUP3P99Y8UkXss+I/VMnYl83cvTyhYTBE+xXo cZnJNJr5EGcHbCKDOw5qzZmWgscClEDk8K70pc2sU5/7TsNOz3qMBup0ghahhpvfFUWg vkZUy83KnTruoWWThCWKQaNjwulexQFfxNHsd7rgNtxCf3BUJ3Swu+Hls5xYOIdyzbqN pTUp3jauqQWIFYhE31Un5fjVTn41lvbrOA703W64zMOhKqcxNHtTJHVm5pwg8QOK9PnF Ba7w== 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=SOwCMPM2O4ZOlwd3DBrA7iEvzDojcSJWVcNWTrD2V3A=; b=qqfsbbw5wVbxlxpoOQZy6dF/hmp2bpx1nn1pUH6i+hfxsyKX5EbN++nY2gCsHxEG1b vXNHNjAJ9CXCkX2mn57QpYVSr7TCU41PnNKvJsttfZcG2HCg9CZFFkIdrA7WN7oCZeUG cBfWA5r5jrGh0zqUaOskHNOqk/e61JNyVXh4HdFCNt9txVryY6Zi+V75/By5KwEsr8jA wZbUwP3q/TKsBr2Xblf1wi2TmWvo9ix96HkfiPNLtAssw9juCcUPEiOrCVV9m5p134ZA y6tOiLyFLNXTSekjr6WQbrGnBpLw+GsGB9uBoTQVNQHMXgva0EXznUHYuDjWINL/4jha yWqw== X-Gm-Message-State: APjAAAUejueY7dYARBFoqVxqQ6RUmKQ5eoMcREF/suGo1KjF4fJe7j4J 17PlK/LHt/+k+ZggSnViFRIF48qANoTKyiSg54cuvA== X-Google-Smtp-Source: APXvYqwitHy/uW9BgFO85xlL31gu4CkfssJm5Y58pk3pu/OFECEhzo8ZcmTg1xeRhUyxbxF5+qEX2qRHXCg/5F+6CB8= X-Received: by 2002:a67:ed8b:: with SMTP id d11mr3107850vsp.104.1572036693631; Fri, 25 Oct 2019 13:51:33 -0700 (PDT) MIME-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20191024225132.13410-1-samitolvanen@google.com> <20191024225132.13410-6-samitolvanen@google.com> In-Reply-To: From: Sami Tolvanen Date: Fri, 25 Oct 2019 13:51:22 -0700 Message-ID: Subject: Re: [PATCH v2 05/17] add support for Clang's Shadow Call Stack (SCS) To: Nick Desaulniers X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191025_135139_182683_62A5D845 X-CRM114-Status: GOOD ( 11.15 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Kees Cook , Ard Biesheuvel , Masahiro Yamada , Catalin Marinas , Jann Horn , LKML , Steven Rostedt , Miguel Ojeda , Masami Hiramatsu , clang-built-linux , Kernel Hardening , Laura Abbott , Will Deacon , Dave Martin , Linux ARM Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Oct 25, 2019 at 9:22 AM Nick Desaulniers wrote: > > +static void scs_free(void *s) > > +{ > > + int i; > > + > > + for (i = 0; i < SCS_CACHE_SIZE; i++) { > > + if (this_cpu_cmpxchg(scs_cache[i], 0, s) != 0) > > + continue; > > + > > + return; > > + } > > prefer: > > for ...: > if foo() == 0: > return > > to: > > for ...: > if foo() != 0: > continue > return This was essentially copied from free_thread_stack in kernel/fork.c, but I agree, your way is cleaner. I'll change this in the next version. Thanks! Sami _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel 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=-8.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 569F7CA9EA0 for ; Fri, 25 Oct 2019 20:51:52 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id A053C21872 for ; Fri, 25 Oct 2019 20:51:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="OMpIHy66" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A053C21872 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-17132-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 21691 invoked by uid 550); 25 Oct 2019 20:51:46 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Received: (qmail 21673 invoked from network); 25 Oct 2019 20:51:45 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=SOwCMPM2O4ZOlwd3DBrA7iEvzDojcSJWVcNWTrD2V3A=; b=OMpIHy666PHw9erjn8xDTPpke8xQntbqoetTb755EO9PeDOpXuqP6XhDAI7uUr5fO2 xmVL8gs1k0UTMM90x7YH/5ifo3akIvmtUP3P99Y8UkXss+I/VMnYl83cvTyhYTBE+xXo cZnJNJr5EGcHbCKDOw5qzZmWgscClEDk8K70pc2sU5/7TsNOz3qMBup0ghahhpvfFUWg vkZUy83KnTruoWWThCWKQaNjwulexQFfxNHsd7rgNtxCf3BUJ3Swu+Hls5xYOIdyzbqN pTUp3jauqQWIFYhE31Un5fjVTn41lvbrOA703W64zMOhKqcxNHtTJHVm5pwg8QOK9PnF Ba7w== 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=SOwCMPM2O4ZOlwd3DBrA7iEvzDojcSJWVcNWTrD2V3A=; b=r1qh50fTbSAMDHj6SghNm/GZgnYdJ6JPifI85uxnmOfF1kcXC8BcyQNrA8rePBfm2Y fVxYNyu7eCG1Z8L6KoYhxkW42m/pW4tSovbFKwYc1X6tVrSC3SvTX6ikYYGXPIcA1Nax 4Z1WoTW8i92ZKKceZAmub8KNoH1rfZ5bIPfgqNPud+LMdM/qaxjNym8zprcUriskmsTg AAwyBBg/OMQRAeyXYSSCnyLkmggQ7AXMvB2VeRuCgmafr4/hlE9wEUM2WklkD9gwQSy9 eXoBo2Nn1DBkBXYL3tXGNtuQQObFOnODLhES6LM9bEm4PAkUAJE9anXZwy2FrQPYm/Zx iikQ== X-Gm-Message-State: APjAAAX+XQSBmZ8nrLO705R2JPrgP3KFHBEJyItnLOmJjfF6RYrJxwQS J1h3A+hZmguXIVFiLF08J9LYE9y5C14mpJ7L8nRF1w== X-Google-Smtp-Source: APXvYqwitHy/uW9BgFO85xlL31gu4CkfssJm5Y58pk3pu/OFECEhzo8ZcmTg1xeRhUyxbxF5+qEX2qRHXCg/5F+6CB8= X-Received: by 2002:a67:ed8b:: with SMTP id d11mr3107850vsp.104.1572036693631; Fri, 25 Oct 2019 13:51:33 -0700 (PDT) MIME-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20191024225132.13410-1-samitolvanen@google.com> <20191024225132.13410-6-samitolvanen@google.com> In-Reply-To: From: Sami Tolvanen Date: Fri, 25 Oct 2019 13:51:22 -0700 Message-ID: Subject: Re: [PATCH v2 05/17] add support for Clang's Shadow Call Stack (SCS) To: Nick Desaulniers Cc: Will Deacon , Catalin Marinas , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel , Dave Martin , Kees Cook , Laura Abbott , Mark Rutland , Jann Horn , Miguel Ojeda , Masahiro Yamada , clang-built-linux , Kernel Hardening , Linux ARM , LKML Content-Type: text/plain; charset="UTF-8" On Fri, Oct 25, 2019 at 9:22 AM Nick Desaulniers wrote: > > +static void scs_free(void *s) > > +{ > > + int i; > > + > > + for (i = 0; i < SCS_CACHE_SIZE; i++) { > > + if (this_cpu_cmpxchg(scs_cache[i], 0, s) != 0) > > + continue; > > + > > + return; > > + } > > prefer: > > for ...: > if foo() == 0: > return > > to: > > for ...: > if foo() != 0: > continue > return This was essentially copied from free_thread_stack in kernel/fork.c, but I agree, your way is cleaner. I'll change this in the next version. Thanks! Sami