From nobody Fri Dec 19 20:06:41 2025 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 697C3C54EBD for ; Mon, 9 Jan 2023 08:47:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236650AbjAIIqs (ORCPT ); Mon, 9 Jan 2023 03:46:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54640 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236968AbjAIIp4 (ORCPT ); Mon, 9 Jan 2023 03:45:56 -0500 Received: from 1wt.eu (wtarreau.pck.nerim.net [62.212.114.60]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id DCD31140B4 for ; Mon, 9 Jan 2023 00:42:52 -0800 (PST) Received: (from willy@localhost) by pcw.home.local (8.15.2/8.15.2/Submit) id 3098gFrt027434; Mon, 9 Jan 2023 09:42:15 +0100 From: Willy Tarreau To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, Willy Tarreau Subject: [PATCH 15/22] tools/nolibc: add auxiliary vector retrieval for arm64 Date: Mon, 9 Jan 2023 09:42:01 +0100 Message-Id: <20230109084208.27355-16-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> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" In the _start block we now iterate over envp to find the auxiliary vector after the NULL. The pointer is saved into an _auxv variable that is marked as weak so that it's accessible from multiple units. Signed-off-by: Willy Tarreau --- tools/include/nolibc/arch-aarch64.h | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/tools/include/nolibc/arch-aarch64.h b/tools/include/nolibc/arc= h-aarch64.h index 2e3d9adc4c4c..383baddef701 100644 --- a/tools/include/nolibc/arch-aarch64.h +++ b/tools/include/nolibc/arch-aarch64.h @@ -170,6 +170,7 @@ struct sys_stat_struct { }) =20 char **environ __attribute__((weak)); +const unsigned long *_auxv __attribute__((weak)); =20 /* startup code */ void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) _start(= void) @@ -182,6 +183,12 @@ void __attribute__((weak,noreturn,optimize("omit-frame= -pointer"))) _start(void) "add x2, x2, x1\n" // + argv "adrp x3, environ\n" // x3 =3D &environ (high bits) "str x2, [x3, #:lo12:environ]\n" // store envp into environ + "mov x4, x2\n" // search for auxv (follows NULL after last env) + "0:\n" + "ldr x5, [x4], 8\n" // x5 =3D *x4; x4 +=3D 8 + "cbnz x5, 0b\n" // and stop at NULL after last env + "adrp x3, _auxv\n" // x3 =3D &_auxv (high bits) + "str x4, [x3, #:lo12:_auxv]\n" // store x4 into _auxv "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 =3D=3D 93 --=20 2.17.5