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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 B8E0AC3F2D2 for ; Fri, 28 Feb 2020 12:14:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 91BEB2087F for ; Fri, 28 Feb 2020 12:14:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582892068; bh=ZC3Ht6M1A+48LStSHQkp1WSEU79DLzGExzetr4ZF0/w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=x0f4zy6acHlm+l9Z4p8c6QridkUR5b/gypFtQr8xIkVqiSX3qa0NY2/lJZO04yYcs JbvOY1j4C6h1JIfq++EYXSvfSZD/vQ9pPVj/4n71xZmrJxACVtCrSuGpUyahs001wD O3gV8uUHz4hfTHj2MK7TDrWU/LULQ27qQzVtl/Oo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725877AbgB1MO1 (ORCPT ); Fri, 28 Feb 2020 07:14:27 -0500 Received: from mail.kernel.org ([198.145.29.99]:45486 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726766AbgB1MOZ (ORCPT ); Fri, 28 Feb 2020 07:14:25 -0500 Received: from e123331-lin.home (amontpellier-657-1-18-247.w109-210.abo.wanadoo.fr [109.210.65.247]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 59959246B2; Fri, 28 Feb 2020 12:14:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582892064; bh=ZC3Ht6M1A+48LStSHQkp1WSEU79DLzGExzetr4ZF0/w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UnjITO2sqVy3QVNwgfkYpE3JnC9TV4GxceehYIpNc6fkn6Fg5tmJ0otBDXLVVAofo TUNp0rs9+RGHdmQXK+/qOSHGpiGig1KpKZVhgiN0ayPCKQgjXmw51YO0NlYdw4y1zH 2G5HLKuEZKMDVcVJIPJMe9q0LEgWvrJO3mqKaIGo= From: Ard Biesheuvel To: linux-efi@vger.kernel.org, Ingo Molnar , Thomas Gleixner Cc: Ard Biesheuvel , linux-kernel@vger.kernel.org, David Hildenbrand , Heinrich Schuchardt , Tom Lendacky Subject: [PATCH 5/6] efi/arm64: clean EFI stub exit code from cache instead of avoiding it Date: Fri, 28 Feb 2020 13:14:07 +0100 Message-Id: <20200228121408.9075-6-ardb@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200228121408.9075-1-ardb@kernel.org> References: <20200228121408.9075-1-ardb@kernel.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit 9f9223778 ("efi/libstub/arm: Make efi_entry() an ordinary PE/COFF entrypoint") modified the handover code written in assembler, and for maintainability, aligned the logic with the logic used in the 32-bit ARM version, which is to avoid cache maintenance on the remaining instructions in the subroutine that will be executed with the MMU and caches off, and instead, branch into the relocated copy of the kernel image. However, this assumes that this copy is executable, and this means we expect EFI_LOADER_DATA regions to be executable as well, which is not a reasonable assumption to make, even if this is true for most UEFI implementations today. So change this back, and add a __clean_dcache_area_poc() call to cover the remaining code in the subroutine. While at it, switch the other call site over to __clean_dcache_area_poc() as well, and clean up the terminology in comments to avoid using 'flush' in the context of cache maintenance. Also, let's switch to the new style asm annotations. Signed-off-by: Ard Biesheuvel --- arch/arm64/kernel/efi-entry.S | 26 +++++++++++++------------- arch/arm64/kernel/image-vars.h | 4 ++-- 2 files changed, 15 insertions(+), 15 deletions(-) diff --git a/arch/arm64/kernel/efi-entry.S b/arch/arm64/kernel/efi-entry.S index 4cfd03c35c49..1a03618df0df 100644 --- a/arch/arm64/kernel/efi-entry.S +++ b/arch/arm64/kernel/efi-entry.S @@ -12,32 +12,32 @@ __INIT -ENTRY(efi_enter_kernel) +SYM_CODE_START(efi_enter_kernel) /* * efi_entry() will have copied the kernel image if necessary and we * end up here with device tree address in x1 and the kernel entry * point stored in x0. Save those values in registers which are * callee preserved. */ - mov x19, x0 // relocated Image address + ldr w2, =stext_offset + add x19, x0, x2 // relocated Image entrypoint mov x20, x1 // DTB address /* - * Flush the copied Image to the PoC, and ensure it is not shadowed by + * Clean the copied Image to the PoC, and ensure it is not shadowed by * stale icache entries from before relocation. */ ldr w1, =kernel_size - bl __flush_dcache_area + bl __clean_dcache_area_poc ic ialluis - dsb sy /* - * Jump across, into the copy of the image that we just cleaned - * to the PoC, so that we can safely disable the MMU and caches. + * Clean the remainder of this routine to the PoC + * so that we can safely disable the MMU and caches. */ - ldr w0, .Ljmp - sub x0, x19, w0, sxtw - br x0 + adr x0, 0f + ldr w1, 3f + bl __clean_dcache_area_poc 0: /* Turn off Dcache and MMU */ mrs x0, CurrentEL @@ -63,6 +63,6 @@ ENTRY(efi_enter_kernel) mov x1, xzr mov x2, xzr mov x3, xzr - b stext -ENDPROC(efi_enter_kernel) -.Ljmp: .long _text - 0b + br x19 +SYM_CODE_END(efi_enter_kernel) +3: .long . - 0b diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h index 9a7aef0d6f70..7f06ad93fc95 100644 --- a/arch/arm64/kernel/image-vars.h +++ b/arch/arm64/kernel/image-vars.h @@ -13,6 +13,7 @@ #ifdef CONFIG_EFI __efistub_kernel_size = _edata - _text; +__efistub_stext_offset = stext - _text; /* @@ -34,7 +35,7 @@ __efistub_strnlen = __pi_strnlen; __efistub_strcmp = __pi_strcmp; __efistub_strncmp = __pi_strncmp; __efistub_strrchr = __pi_strrchr; -__efistub___flush_dcache_area = __pi___flush_dcache_area; +__efistub___clean_dcache_area_poc = __pi___clean_dcache_area_poc; #ifdef CONFIG_KASAN __efistub___memcpy = __pi_memcpy; @@ -43,7 +44,6 @@ __efistub___memset = __pi_memset; #endif __efistub__text = _text; -__efistub_stext = stext; __efistub__end = _end; __efistub__edata = _edata; __efistub_screen_info = screen_info; -- 2.17.1