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[2620:137:e000::1:20]) by mx.google.com with ESMTP id t1-20020a170902d14100b00192a363c32bsi7882114plt.571.2023.01.09.00.49.29; Mon, 09 Jan 2023 00:49:41 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236534AbjAIIt2 (ORCPT + 99 others); Mon, 9 Jan 2023 03:49:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54212 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236812AbjAIIsJ (ORCPT ); Mon, 9 Jan 2023 03:48:09 -0500 Received: from 1wt.eu (wtarreau.pck.nerim.net [62.212.114.60]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 3E60C165A0 for ; Mon, 9 Jan 2023 00:43:39 -0800 (PST) Received: (from willy@localhost) by pcw.home.local (8.15.2/8.15.2/Submit) id 3098gDWp027427; Mon, 9 Jan 2023 09:42:13 +0100 From: Willy Tarreau To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, Willy Tarreau Subject: [PATCH 08/22] tools/nolibc: export environ as a weak symbol on arm64 Date: Mon, 9 Jan 2023 09:41:54 +0100 Message-Id: <20230109084208.27355-9-w@1wt.eu> X-Mailer: git-send-email 2.17.5 In-Reply-To: <20230109084208.27355-1-w@1wt.eu> References: <20230109084208.27355-1-w@1wt.eu> X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,SPF_HELO_PASS, SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1754534177277388393?= X-GMAIL-MSGID: =?utf-8?q?1754534177277388393?= The environ is retrieved from the _start code and is easy to store at this moment. Let's declare the variable weak and store the value into it. By not being static it will be visible to all units. By being weak, if some programs already declared it, they will continue to be able to use it. This was tested both with environ inherited from _start and extracted from envp. Signed-off-by: Willy Tarreau --- tools/include/nolibc/arch-aarch64.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/tools/include/nolibc/arch-aarch64.h b/tools/include/nolibc/arch-aarch64.h index f480993159ec..2e3d9adc4c4c 100644 --- a/tools/include/nolibc/arch-aarch64.h +++ b/tools/include/nolibc/arch-aarch64.h @@ -169,6 +169,8 @@ struct sys_stat_struct { _arg1; \ }) +char **environ __attribute__((weak)); + /* startup code */ void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) _start(void) { @@ -178,6 +180,8 @@ void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) _start(void) "lsl x2, x0, 3\n" // envp (x2) = 8*argc ... "add x2, x2, 8\n" // + 8 (skip null) "add x2, x2, x1\n" // + argv + "adrp x3, environ\n" // x3 = &environ (high bits) + "str x2, [x3, #:lo12:environ]\n" // store envp into environ "and sp, x1, -16\n" // sp must be 16-byte aligned in the callee "bl main\n" // main() returns the status code, we'll exit with it. "mov x8, 93\n" // NR_exit == 93