From patchwork Fri Jun 2 10:12:55 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 688920 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 AEF49C7EE24 for ; Fri, 2 Jun 2023 10:22:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235357AbjFBKWu (ORCPT ); Fri, 2 Jun 2023 06:22:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45876 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235342AbjFBKWX (ORCPT ); Fri, 2 Jun 2023 06:22:23 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 83AD11AE; Fri, 2 Jun 2023 03:22:21 -0700 (PDT) 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 05C0464E71; Fri, 2 Jun 2023 10:22:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7A312C4339C; Fri, 2 Jun 2023 10:22:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1685701340; bh=+pOeFG4I2M0NxWTqt2DlFeFWBXmc5I0TflwHlC5RHXA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZHQQ8iiabB8LyufShp63/BFbUFbzOsYVWTKUi65Muc89+1LlzSmC4seQ4t5NnekYW q3amSyw7qDJpJgAyzuClLUQ7PNqWnsuOwFCAS6/xoEyBBmv9gb+Q5OKkmYLrUAft1m +RSn0pbgLQ82JlXs70oJnJXuOpa8EyTaBm5N45QdyDML95rmNZa/Rchlvv36h1n3bX UYMM8V/chWu+W8URIXqRvjD1ZXRVbayKKYZxOklXL/wBgc+iVr6Ayn/NIXny2SCBi3 kQ5ypVcJWllJpClE0XKIB57ucg9ULU++xnhhQ3pRG8UnBLugQiySiwAraJCOAm78s/ 97tKMrlBS55lg== From: Ard Biesheuvel To: linux-efi@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Ard Biesheuvel , Evgeniy Baskov , Borislav Petkov , Andy Lutomirski , Dave Hansen , Ingo Molnar , Peter Zijlstra , Thomas Gleixner , Alexey Khoroshilov , Peter Jones , Gerd Hoffmann , Dave Young , Mario Limonciello , Kees Cook , Tom Lendacky , "Kirill A . Shutemov" , Linus Torvalds , Joerg Roedel Subject: [PATCH v4 03/21] x86/decompressor: Avoid magic offsets for EFI handover entrypoint Date: Fri, 2 Jun 2023 12:12:55 +0200 Message-Id: <20230602101313.3557775-4-ardb@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230602101313.3557775-1-ardb@kernel.org> References: <20230602101313.3557775-1-ardb@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3376; i=ardb@kernel.org; h=from:subject; bh=+pOeFG4I2M0NxWTqt2DlFeFWBXmc5I0TflwHlC5RHXA=; b=owGbwMvMwCFmkMcZplerG8N4Wi2JIaXywOI3HT6SmyscomyMjU58fXF7TUzazdYEE8dZQYfXb 9MJ36HZUcrCIMbBICumyCIw+++7nacnStU6z5KFmcPKBDKEgYtTACbyjJvhD//d1w33X2q9MVm8 xXJS1KQJbA3zJ/9Ss5v14eNruejeKZMY/tfet08tOHyzIObI+l2dwpuNLC4pM+6Z6me5JWVaT8W RN0wA X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org The native 32-bit or 64-bit EFI handover protocol entrypoint offset relative to the respective startup_32/64 address is described in boot_params as handover_offset, so that the special Linux/x86 aware EFI loader can find it there. When mixed mode is enabled, this single field has to describe this offset for both the 32-bit and 64-bit entrypoints, so their respective relative offsets have to be identical. Given that startup_32 and startup_64 are 0x200 bytes apart, and the EFI handover entrypoint resides at a fixed offset, the 32-bit and 64-bit versions of those entrypoints must be exactly 0x200 bytes apart as well. Currently, hard-coded fixed offsets are used to ensure this, but it is sufficient to emit the 64-bit entrypoint 0x200 bytes after the 32-bit one, wherever it happens to reside. This allows this code (which is now EFI mixed mode specific) to be moved into efi_mixed.S and out of the startup code in head_64.S. Signed-off-by: Ard Biesheuvel --- arch/x86/boot/compressed/efi_mixed.S | 20 +++++++++++++++++++- arch/x86/boot/compressed/head_64.S | 18 ------------------ 2 files changed, 19 insertions(+), 19 deletions(-) diff --git a/arch/x86/boot/compressed/efi_mixed.S b/arch/x86/boot/compressed/efi_mixed.S index dcc562c8f7f35162..9308b595f6f0a5de 100644 --- a/arch/x86/boot/compressed/efi_mixed.S +++ b/arch/x86/boot/compressed/efi_mixed.S @@ -140,6 +140,16 @@ SYM_FUNC_START(__efi64_thunk) SYM_FUNC_END(__efi64_thunk) .code32 +#ifdef CONFIG_EFI_HANDOVER_PROTOCOL +SYM_FUNC_START(efi32_stub_entry) + add $0x4, %esp /* Discard return address */ + popl %ecx + popl %edx + popl %esi + jmp efi32_entry +SYM_FUNC_END(efi32_stub_entry) +#endif + /* * EFI service pointer must be in %edi. * @@ -220,7 +230,7 @@ SYM_FUNC_END(efi_enter32) * stub may still exit and return to the firmware using the Exit() EFI boot * service.] */ -SYM_FUNC_START(efi32_entry) +SYM_FUNC_START_LOCAL(efi32_entry) call 1f 1: pop %ebx @@ -320,6 +330,14 @@ SYM_FUNC_START(efi32_pe_entry) RET SYM_FUNC_END(efi32_pe_entry) +#ifdef CONFIG_EFI_HANDOVER_PROTOCOL + .org efi32_stub_entry + 0x200 + .code64 +SYM_FUNC_START_NOALIGN(efi64_stub_entry) + jmp efi_stub_entry +SYM_FUNC_END(efi64_stub_entry) +#endif + .section ".rodata" /* EFI loaded image protocol GUID */ .balign 4 diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 71c1f40a7ac067b9..9f90661744741210 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -294,17 +294,6 @@ SYM_FUNC_START(startup_32) lret SYM_FUNC_END(startup_32) -#if IS_ENABLED(CONFIG_EFI_MIXED) && IS_ENABLED(CONFIG_EFI_HANDOVER_PROTOCOL) - .org 0x190 -SYM_FUNC_START(efi32_stub_entry) - add $0x4, %esp /* Discard return address */ - popl %ecx - popl %edx - popl %esi - jmp efi32_entry -SYM_FUNC_END(efi32_stub_entry) -#endif - .code64 .org 0x200 SYM_CODE_START(startup_64) @@ -523,13 +512,6 @@ trampoline_return: jmp *%rax SYM_CODE_END(startup_64) -#if IS_ENABLED(CONFIG_EFI_MIXED) && IS_ENABLED(CONFIG_EFI_HANDOVER_PROTOCOL) - .org 0x390 -SYM_FUNC_START(efi64_stub_entry) - jmp efi_stub_entry -SYM_FUNC_END(efi64_stub_entry) -#endif - .text SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated)