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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 038DDC4332F for ; Wed, 4 Jan 2023 14:43:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236451AbjADOnI (ORCPT ); Wed, 4 Jan 2023 09:43:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60982 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239671AbjADOmi (ORCPT ); Wed, 4 Jan 2023 09:42:38 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 17267188; Wed, 4 Jan 2023 06:42:37 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A393D6176B; Wed, 4 Jan 2023 14:42:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CA3CEC433F2; Wed, 4 Jan 2023 14:42:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1672843356; bh=2h6S36bZJ85jADuzLHYnhUt+Q2Kq22quMH8ZU54eN8c=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=cjVd33us2AS+rA9ls3Z47M+j6oGpkMzpBLYCVej146IZ7dho6+IDlN2eVyCAzilwb Re7dfGegDBUc3CxEEfNsEbLj58NEu/8DIAWUAXR1A3TjHriVXFGd3Mi1EpaEGnSuli jwnGTH2m62ntlBchVJoWRykTOXlLov+xkcKk/Apz8xpEhxKi/seIfRVhd5dXByYndK KnTvWvDcEWwY+DCOyPkag504YwAjp8UnmzswlGQbUjjmvzTH03XPnaDFCAfpxCdiut MBiISMlJsw63dSfizcCVt1LwZYb030tZR9BFDEB2ErXmeKFye7LOSJF47IE0CKT3gz FAxHFm5pL70zw== Date: Wed, 4 Jan 2023 14:42:30 +0000 From: Lee Jones To: Ard Biesheuvel Cc: stable@vger.kernel.org, linux-efi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, will@kernel.org, catalin.marinas@arm.com, mark.rutland@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-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Wed, 04 Jan 2023, 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. Perfect, thanks Ard. -- Lee Jones [李琼斯]