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 2D25FC47E49 for ; Thu, 31 Oct 2019 17:35:24 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 705AE208C0 for ; Thu, 31 Oct 2019 17:35:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Zkd+dczq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 705AE208C0 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-17207-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 14294 invoked by uid 550); 31 Oct 2019 17:35:17 -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 14266 invoked from network); 31 Oct 2019 17:35:16 -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=6vxne2J2U+zueRlGB+uihx88K5obGcz7JfVVNIfE6MI=; b=Zkd+dczqhPUCvaVxq3B8963P3V8Y9R+M6ldUJWVSSAWMYKxKqeHtnfr2PdTP/xQu2b M24kRR6f+BemlR/4Y0IvK/z1JsB3EOLUV7taiH84F2Ii6S/051a5P0kFaw58bDYFmRYl aNg+ivt2iWFLU8ljqbd20wQiN/S62lqFSuUkwS/f02KuHQnSP26/xslqjUm0PxnUl/nM qI0N36UakRSXzfSUr6wSxS+I2jAHofRSRz2rGKpUptLXuoFXn9q5tA4/x48cLuSowzWM m7sGquCCjWRdIn+Z2H+0+h0T7us+31n+XfF8IpapK82l/iCdOiiKW9oFk4wdTg6QArPU kr1w== 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=6vxne2J2U+zueRlGB+uihx88K5obGcz7JfVVNIfE6MI=; b=fVaMEwQgSpuutPDeM22ZiKPwGexfidWqN5j7kVf1Ik/yb3fzwBK1ihwIgD5z8X+27s F3sswqdci0nY8oPd6ULXAOWpo4n80vHB8KMp2czG3plcBx5hHneL1REhGeXDreJhlMB1 TwxxHqs9aTskdd4vEqRvY6nTMfLgCISz0B30lt5CtS537IW3R/plzlEfACUXenc5OtOp shv67/smRnzRG/mb9Xjfd5AKlaJUDeRkUe+zLypK9T4c7xT8GzTjk8TnKYei7dp2rQUS Wc6vaJUx0m9HiBbb1qb0+xLT32yT22e12POS8JxvE7q3c/wpmT2uv+9wvQoVAP8HRXJD fFaA== X-Gm-Message-State: APjAAAWmf++jnDAF5DJeyOE/DrOrhirG4LH0L8rwJa+x7McDtU32M60Q CFQgrZyLSlkmv98GPyjTvVs/UOnvEvFdYtGGxiDR/w== X-Google-Smtp-Source: APXvYqz/lhCOKKkE7+XVjZtp5lyRajdclaBkyDSosLmDck7GxCYMMFfzkg348/A5b/zQnTjld0uu3Efy3NYsSqb59C8= X-Received: by 2002:a17:90a:1f4b:: with SMTP id y11mr8889337pjy.123.1572543304777; Thu, 31 Oct 2019 10:35:04 -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: Nick Desaulniers Date: Thu, 31 Oct 2019 10:34:53 -0700 Message-ID: Subject: Re: [PATCH v3 13/17] arm64: preserve x18 when CPU is suspended To: Sami Tolvanen 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 10:27 AM Sami Tolvanen wrote: > > 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. That sounds like a good idea. Consider adding comments or to the commit message so that the str doesn't get removed accidentally in the future. Reviewed-by: Nick Desaulniers -- Thanks, ~Nick Desaulniers