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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 6A8D3C4708D for ; Wed, 4 Jan 2023 16:16:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=rHgWx1occ3/RaKPg8VrO8UOwz6i306HHCLUvdUazYt4=; b=cY9hBiEWLKdeec /h7zqXvM6jBTxa701CHZ5CFI7xCWdTq8UevhXdLRYRNRmOLmTHNsdqPsNSExMCVgrVPK6MaSdnkWQ dtvDyEoJi8HxSjTcoiwjkDeuIvYOWYLCr4tsS678CpW/tEhOKitu0NWFalnJDDcVcV/7i7U8KRHvV pE/GC+9ybFb3bLFaoNQcEOLD6+mgF0wxYvBq09nt7t+fpkDeZ5OQX925MGNL+qzhUuJTY8mdZPW3i 0JpjPgM0buU0lL2Na3oT+hgrFtPtLr2f/q1aLLgPgCgfJMU2jB61W45bQzoXkUIiJGxVLjVMfjpbB E0vuYoIVSXSLdus+daKw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pD6QT-00AKgA-Vi; Wed, 04 Jan 2023 16:15:38 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pD6OV-00AK0t-1O for linux-arm-kernel@lists.infradead.org; Wed, 04 Jan 2023 16:13:36 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1E07E165C; Wed, 4 Jan 2023 08:14:12 -0800 (PST) Received: from FVFF77S0Q05N (unknown [10.57.37.146]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E6AA63F71A; Wed, 4 Jan 2023 08:13:28 -0800 (PST) Date: Wed, 4 Jan 2023 16:13:22 +0000 From: Mark Rutland To: Ard Biesheuvel Cc: Lee Jones , stable@vger.kernel.org, linux-efi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, will@kernel.org, catalin.marinas@arm.com, Sami Tolvanen , Kees Cook Subject: Re: [PATCH 1/2] arm64: efi: Execute runtime services from a dedicated stack Message-ID: References: <20221205201210.463781-1-ardb@kernel.org> <20221205201210.463781-2-ardb@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230104_081335_188787_4618FD9E X-CRM114-Status: GOOD ( 25.88 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Jan 04, 2023 at 02:56:19PM +0100, Ard Biesheuvel wrote: > On Wed, 4 Jan 2023 at 11:40, Lee Jones wrote: > > > > On Mon, 05 Dec 2022, Ard Biesheuvel wrote: > > > > > With the introduction of PRMT in the ACPI subsystem, the EFI rts > > > workqueue is no longer the only caller of efi_call_virt_pointer() in the > > > kernel. This means the EFI runtime services lock is no longer sufficient > > > to manage concurrent calls into firmware, but also that firmware calls > > > may occur that are not marshalled via the workqueue mechanism, but > > > originate directly from the caller context. > > > > > > For added robustness, and to ensure that the runtime services have 8 KiB > > > of stack space available as per the EFI spec, introduce a spinlock > > > protected EFI runtime stack of 8 KiB, where the spinlock also ensures > > > serialization between the EFI rts workqueue (which itself serializes EFI > > > runtime calls) and other callers of efi_call_virt_pointer(). > > > > > > While at it, use the stack pivot to avoid reloading the shadow call > > > stack pointer from the ordinary stack, as doing so could produce a > > > gadget to defeat it. > > > > > > Signed-off-by: Ard Biesheuvel > > > --- > > > arch/arm64/include/asm/efi.h | 3 +++ > > > arch/arm64/kernel/efi-rt-wrapper.S | 13 +++++++++- > > > arch/arm64/kernel/efi.c | 25 ++++++++++++++++++++ > > > 3 files changed, 40 insertions(+), 1 deletion(-) > > > > Could we have this in Stable please? > > > > Upstream commit: ff7a167961d1b ("arm64: efi: Execute runtime services from a dedicated stack") > > > > Ard, do we need Patch 2 as well, or can this be applied on its own? > > > > Thanks for the reminder. > > Only patch #1 is needed. It should be applied to v5.10 and later. Hold on, why did this go into mainline when I had an outstanding comment w.r.t. the stack unwinder? >From your last reply to me there I was expecting a respin with that fixed. Mark. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel