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 17FA2CA9ECB for ; Thu, 31 Oct 2019 17:27:59 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 5EE412086D for ; Thu, 31 Oct 2019 17:27:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="uKrGepNX" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5EE412086D 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-17205-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 7566 invoked by uid 550); 31 Oct 2019 17:27:52 -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 7534 invoked from network); 31 Oct 2019 17:27:51 -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=46AmydREw6SfU27IOaxxeyDyoZWG9jeVi2WIEFhrMqA=; b=uKrGepNXzPXDPzJbvbemKuf7R6S5LOyd1Myup06RKzLSP2nrNd0gQdYUKo5Mow3DAS +SE7IfD6gsDwY0qy8BSl0pYU8GPWYV87yKCwXeFmUj8tfcvjCxE6XCZvWViSX7BLJr2h JeRICf0gxuCWKgnMwiCuZSLMzerlDUIsThoYOFbNVmV4Iio6o99JIWYLgpdzR7oI4BDx tISF+YHwsfL5BB8DS6m0YqBcFdYRIfZsqtAtZCMGUCUGgOjGgmE4qf5gvZ9MBWNon0hF l2JKhPx8hF2es29OTb38GxXTjoyqOeNJvDE0LRnzacnT1nPR0db8A8Us17QUjMd2B+Rn jUDw== 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=46AmydREw6SfU27IOaxxeyDyoZWG9jeVi2WIEFhrMqA=; b=K5RBC7V/byjIlzeFYiND2Bif2AxJmeXraPSzxCf4ss7TD52JJj8KE2mR8YecQrBG14 JZ3Iuc2fQ15YLnBcfwkobf/coAcpj9/iLvs2Att2mnRpQal2Lb8NGM5db6ZT3ldEKpky goxW53sYkKMGZhQeTD4CoAKIZ8Trd7fCr/kd6tUkudr+TfvJAfeQO8ZZZ7bhK2YLcx+O 6ApM3m0bZ+QZlgOfMfegCk5cQLdfcmuE4BRC7S6kyZV5zoTTg+R2UKWfjaQj1tSEMYO6 4Z5RqNSLErWi3SyJxYkGjj6g/bTFzOPG4I0vnOi2Dj4m2XrrmaxRlrfaysIWWHIl7P+4 1x0w== X-Gm-Message-State: APjAAAVDEn0CNNd15I2kQ+UDBpskrq56TIbukOvH8M6wxWQrFziG3KD/ zSw7SLEuD+x3i843VI68dYjHPaESxkn07S5zUOJ7MA== X-Google-Smtp-Source: APXvYqwHBpr5C3UNKE6XLzBUe1Jy/aZ4Jd12qOfI93i2wDsaUH2oAUrgK4KH1mAvPJ/zcWPVngS0f/6vsb1FU+PAYk8= X-Received: by 2002:a9f:3772:: with SMTP id a47mr3382097uae.53.1572542858440; Thu, 31 Oct 2019 10:27:38 -0700 (PDT) MIME-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20191031164637.48901-1-samitolvanen@google.com> <20191031164637.48901-14-samitolvanen@google.com> In-Reply-To: From: Sami Tolvanen Date: Thu, 31 Oct 2019 10:27:26 -0700 Message-ID: Subject: Re: [PATCH v3 13/17] arm64: preserve x18 when CPU is suspended 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 Thu, Oct 31, 2019 at 10:18 AM Nick Desaulniers wrote: > > +#ifdef CONFIG_SHADOW_CALL_STACK > > + ldr x18, [x0, #96] > > + str xzr, [x0, #96] > > How come we zero out x0+#96, but not for other offsets? Is this str necessary? It clears the shadow stack pointer from the sleep state buffer, which is not strictly speaking necessary, but leaves one fewer place to find it. Sami