From nobody Wed Oct 1 20:41:28 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 8DA67C001E0 for ; Sat, 15 Jul 2023 18:24:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229549AbjGOSYn (ORCPT ); Sat, 15 Jul 2023 14:24:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42354 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229472AbjGOSYl (ORCPT ); Sat, 15 Jul 2023 14:24:41 -0400 Received: from bg4.exmail.qq.com (bg4.exmail.qq.com [43.155.65.254]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 47C3126AF; Sat, 15 Jul 2023 11:24:39 -0700 (PDT) X-QQ-mid: bizesmtp66t1689445470tmh7la4l Received: from linux-lab-host.localdomain ( [119.123.131.162]) by bizesmtp.qq.com (ESMTP) with id ; Sun, 16 Jul 2023 02:24:29 +0800 (CST) X-QQ-SSF: 01200000002000D0W000B00A0000000 X-QQ-FEAT: XBN7tc9DADLd+8HjQGb0FOWlOVPqo5Ahl4SrFFvntkNjTbYnk6cZ4spbHoNlE oi7hFMRBk9vB/IF5nDv1ubzWujRzBVzSaUAU3tsTlmDlhiEgfrWUeXeCaK7a8NaHGY3oaFv HNc/y/DivXfWCkWcezk1+++8WCaUbrICbieLR1R/TbU/p/2geyJUuX3ClF/KKToZKd0x/ub c+ILyKS1XwMF8wn2NIoDufokixLCrj5g/9RC+KW1/W1U97MT/j9C/Qcb89cICTlybihlO0b JA+MUErYgOOljYQQ0OrgMI6DXToHIF4LRKnd5q2f4BSpmDaYGstKIIaIlIQT1/U/GP9eIGn wMQacP38nQH7gRoU8tNhXc3H8jZjo/EJvCOqyKh3fKy6xgduGTMefaGjcCvPg== X-QQ-GoodBg: 0 X-BIZMAIL-ID: 6138912096365051430 From: Zhangjin Wu To: w@1wt.eu Cc: arnd@arndb.de, falcon@tinylab.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, thomas@t-8ch.de Subject: [PATCH v4 07/18] tools/nolibc: arm: shrink _start with _start_c Date: Sun, 16 Jul 2023 02:24:29 +0800 Message-Id: <5cdded9a3bd45b035ab25cba1996745d7009f02e.1689444638.git.falcon@tinylab.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-QQ-SENDSIZE: 520 Feedback-ID: bizesmtp:tinylab.org:qybglogicsvrgz:qybglogicsvrgz5a-1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" move most of the _start operations to _start_c(), include the stackprotector initialization. Signed-off-by: Zhangjin Wu --- tools/include/nolibc/arch-arm.h | 44 ++++----------------------------- 1 file changed, 5 insertions(+), 39 deletions(-) diff --git a/tools/include/nolibc/arch-arm.h b/tools/include/nolibc/arch-ar= m.h index a06dad789a22..cae4afa7c1c7 100644 --- a/tools/include/nolibc/arch-arm.h +++ b/tools/include/nolibc/arch-arm.h @@ -8,6 +8,7 @@ #define _NOLIBC_ARCH_ARM_H =20 #include "compiler.h" +#include "crt.h" =20 /* Syscalls for ARM in ARM or Thumb modes : * - registers are 32-bit @@ -183,49 +184,14 @@ _arg1; \ }) =20 - -char **environ __attribute__((weak)); -const unsigned long *_auxv __attribute__((weak)); - /* startup code */ void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer")))= __no_stack_protector _start(void) { __asm__ volatile ( -#ifdef _NOLIBC_STACKPROTECTOR - "bl __stack_chk_init\n" /* initialize stack protector = */ -#endif - "pop {%r0}\n" /* argc was in the stack = */ - "mov %r1, %sp\n" /* argv =3D sp = */ - - "add %r2, %r0, $1\n" /* envp =3D (argc + 1) ... = */ - "lsl %r2, %r2, $2\n" /* * 4 ... = */ - "add %r2, %r2, %r1\n" /* + argv = */ - "ldr %r3, 1f\n" /* r3 =3D &environ (see below) = */ - "str %r2, [r3]\n" /* store envp into environ = */ - - "mov r4, r2\n" /* search for auxv (follows NULL after las= t env) */ - "0:\n" - "mov r5, r4\n" /* r5 =3D r4 = */ - "add r4, r4, #4\n" /* r4 +=3D 4 = */ - "ldr r5,[r5]\n" /* r5 =3D *r5 =3D *(r4-4) = */ - "cmp r5, #0\n" /* and stop at NULL after last env = */ - "bne 0b\n" - "ldr %r3, 2f\n" /* r3 =3D &_auxv (low bits) = */ - "str r4, [r3]\n" /* store r4 into _auxv = */ - - "mov %r3, $8\n" /* AAPCS : sp must be 8-byte aligned in th= e */ - "neg %r3, %r3\n" /* callee, and bl doesn't push (lr= =3Dpc) */ - "and %r3, %r3, %r1\n" /* so we do sp =3D r1(=3Dsp) & r3(=3D-8); = */ - "mov %sp, %r3\n" - - "bl main\n" /* main() returns the status code, we'll e= xit with it. */ - "movs r7, $1\n" /* NR_exit =3D=3D 1 = */ - "svc $0x00\n" - ".align 2\n" /* below are the pointers to a few variabl= es */ - "1:\n" - ".word environ\n" - "2:\n" - ".word _auxv\n" + "mov %r0, sp\n" /* save stack pointer to %r0, as arg1 of _start_= c */ + "and ip, %r0, #-8\n" /* sp must be 8-byte aligned in the callee = */ + "mov sp, ip\n" + "bl _start_c\n" /* transfer to c runtime = */ ); __builtin_unreachable(); } --=20 2.25.1