From patchwork Mon Aug 7 16:27:02 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 711361 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 37B3FC04FE0 for ; Mon, 7 Aug 2023 16:28:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231599AbjHGQ2T (ORCPT ); Mon, 7 Aug 2023 12:28:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34128 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231574AbjHGQ1y (ORCPT ); Mon, 7 Aug 2023 12:27:54 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4718D1730; Mon, 7 Aug 2023 09:27:53 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D3AD261EE4; Mon, 7 Aug 2023 16:27:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B9F93C433BC; Mon, 7 Aug 2023 16:27:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1691425672; bh=xRhTT2+byAfO6pNmqeeH4nhZlxaMSyvvxIeRonTKD/w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=U9pve1407ZOK2AakSLMJBz+xOiFgTxHsJneVfIzW9DgxwOKUcRjQTmc1fGpO9BaO+ D7jRNzJ6OhBL1kvA7R6bRvKttcp8r/0m4MKuuJeMnyF3tXTDRK07FtKEtsMIrIur2S Vx+knj49DplqRt2qP3w0Szi2I1qqxhifGYKtZOnRYvs/oWgRvKfpjBjEnC/rgLC45P wNWBrcfbG7HQ9IVzhWsSw6dEEoDtZxCIx+KFRaIaagwNJ9wbMioqBS4w5QA1DkI/Qk cud3bW8ulu+7byAbFPt/wdbBlny2XIFVWNf3aYPUhGuL/c7+hJyPYYGebgJYz+iaDD J6ATDl5RfD0xg== From: Ard Biesheuvel To: linux-efi@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Ard Biesheuvel , Borislav Petkov , Dave Hansen , Ingo Molnar , Thomas Gleixner Subject: [PATCH v9 05/23] x86/decompressor: Avoid magic offsets for EFI handover entrypoint Date: Mon, 7 Aug 2023 18:27:02 +0200 Message-Id: <20230807162720.545787-6-ardb@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230807162720.545787-1-ardb@kernel.org> References: <20230807162720.545787-1-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=xRhTT2+byAfO6pNmqeeH4nhZlxaMSyvvxIeRonTKD/w=; b=owGbwMvMwCFmkMcZplerG8N4Wi2JIeWidMBNkVCxP7rM9nl+Zz4wi+bMdvs6M3Fx4GupK42LJ t8LXva8o5SFQYyDQVZMkUVg9t93O09PlKp1niULM4eVCWQIAxenAEzEaTfD/5zSv38LlIqEVsb9 mTmnL7ND6/eci6/OPX/hZPPpzc892/8z/M+M7jZc5Xp6o/prs4wv+cl8f8KnS+6aWrFGQeikyc2 1rgwA 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 e6880208b9a1b90a..a3f764daf3a3adbc 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) @@ -542,13 +531,6 @@ 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)