From patchwork Sat Oct 7 17:04:46 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Masahiro Yamada X-Patchwork-Id: 13412430 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 9BBB0E95A61 for ; Sat, 7 Oct 2023 17:05:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344118AbjJGRFE (ORCPT ); Sat, 7 Oct 2023 13:05:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56746 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344098AbjJGRFB (ORCPT ); Sat, 7 Oct 2023 13:05:01 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BE623B9; Sat, 7 Oct 2023 10:04:59 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 23CA5C433C8; Sat, 7 Oct 2023 17:04:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1696698299; bh=7PA8scmHfu5nyFOhItoPibMephbX/u9X82eA3NzQP1c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LWnn0sOt6WygtD1hvtwiVIqmKHBDxYUleCmm8Su8hd/lnUJvGVbe6sHfuJl7ZjjA8 pZ96QAL2xYi7Egbrrdjvt0EvwffMJKtblV8mUCndaQJ2RZJAoTQibExZrVfXJykOnj aWSpG0WDrEdYgYLSX33jj/riVgkH8hz3+x/rwrSdyQsPVmBDpQ12ADSFv3EiQADHaY J8cCrKBe64utnoCGPbxGVmreLogcNc4NqaPkbm5XwX4Abes0XcwIAeQBco/YFqve0Q 0kNqxSJHhRmkr4BW2uaIYynAZfKuDg+aL1DvDsjChq5pL746vpys8wjaVLH/1nrUI5 f9e2VYHEtY3FA== From: Masahiro Yamada To: linux-kbuild@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Masahiro Yamada , Nathan Chancellor , Nick Desaulniers , Nicolas Schier Subject: [PATCH 3/5] modpost: define TO_NATIVE() using bswap_* functions Date: Sun, 8 Oct 2023 02:04:46 +0900 Message-Id: <20231007170448.505487-3-masahiroy@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231007170448.505487-1-masahiroy@kernel.org> References: <20231007170448.505487-1-masahiroy@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org The current TO_NATIVE() has some limitations: 1) You cannot cast the argument. 2) You cannot pass a variable marked as 'const'. 3) Passing an array is a bug, but it is not detected. Impelement TO_NATIVE() using bswap_*() functions. These are GNU extensions. If we face portability issues, we can port the code from include/uapi/linux/swab.h. With this change, get_rel_type_and_sym() can be simplified by casting the arguments directly. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers --- scripts/mod/modpost.c | 13 ++++--------- scripts/mod/modpost.h | 25 ++++++++++++------------- 2 files changed, 16 insertions(+), 22 deletions(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 2f3b0fe6f68d..99476a9695c5 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1410,15 +1410,10 @@ static void get_rel_type_and_sym(struct elf_info *elf, uint64_t r_info, return; } - if (is_64bit) { - Elf64_Xword r_info64 = r_info; - - r_info = TO_NATIVE(r_info64); - } else { - Elf32_Word r_info32 = r_info; - - r_info = TO_NATIVE(r_info32); - } + if (is_64bit) + r_info = TO_NATIVE((Elf64_Xword)r_info); + else + r_info = TO_NATIVE((Elf32_Word)r_info); *r_type = ELF_R_TYPE(r_info); *r_sym = ELF_R_SYM(r_info); diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h index 6413f26fcb6b..1392afec118c 100644 --- a/scripts/mod/modpost.h +++ b/scripts/mod/modpost.h @@ -1,4 +1,5 @@ /* SPDX-License-Identifier: GPL-2.0 */ +#include #include #include #include @@ -51,21 +52,19 @@ #define ELF_R_TYPE ELF64_R_TYPE #endif +#define bswap(x) \ +({ \ + _Static_assert(sizeof(x) == 1 || sizeof(x) == 2 || \ + sizeof(x) == 4 || sizeof(x) == 8, "bug"); \ + (typeof(x))(sizeof(x) == 2 ? bswap_16(x) : \ + sizeof(x) == 4 ? bswap_32(x) : \ + sizeof(x) == 8 ? bswap_64(x) : \ + x); \ +}) + #if KERNEL_ELFDATA != HOST_ELFDATA -static inline void __endian(const void *src, void *dest, unsigned int size) -{ - unsigned int i; - for (i = 0; i < size; i++) - ((unsigned char*)dest)[i] = ((unsigned char*)src)[size - i-1]; -} - -#define TO_NATIVE(x) \ -({ \ - typeof(x) __x; \ - __endian(&(x), &(__x), sizeof(__x)); \ - __x; \ -}) +#define TO_NATIVE(x) (bswap(x)) #else /* endianness matches */