From patchwork Wed Jun 28 18:55:48 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhangjin Wu X-Patchwork-Id: 697584 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 7C2ADEB64D7 for ; Wed, 28 Jun 2023 18:58:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231452AbjF1S6V (ORCPT ); Wed, 28 Jun 2023 14:58:21 -0400 Received: from bg4.exmail.qq.com ([43.155.65.254]:22828 "EHLO bg4.exmail.qq.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232414AbjF1S4a (ORCPT ); Wed, 28 Jun 2023 14:56:30 -0400 X-QQ-mid: bizesmtp66t1687978579tbslkfmx Received: from linux-lab-host.localdomain ( [116.30.129.193]) by bizesmtp.qq.com (ESMTP) with id ; Thu, 29 Jun 2023 02:56:18 +0800 (CST) X-QQ-SSF: 01200000000000D0W000000A0000000 X-QQ-FEAT: CR3LFp2JE4myL95Bwy4YA+PlVj9c4rCxTO0cf3tpSnq4AppLl9rYNCM+pxYWU 85WwvNW4tuBtdM9saYd8fKHWyVNTzgqBFOQ7Tj573N32L3L1hma3fsXS3oAm9gSuKH5AlVo 1u5B3rl7TURqs7ZPJv1OvrdgdefC0C2rpabwBjDRYuzh3a9DpjzBIpMdzyxF0JI3wfddcDj uUXMsItEirc4c2MVlSNMaqgOIKlKB0UQdoQOlBSNOkT7vrAHYpAloMkgLUBN4kDzl2fJ0FX /DCeTcsJQUsNseXiYNiJ1Hf0b47baGzRqIoVb5tN/PKl0Cj8RCn4vMkP7eQHzi7Eu/LXNOU PHrAGTFqRGq3xyDEU4qlJPzKdstMgA8zU1cFTjbSr9TWNOl0jg= X-QQ-GoodBg: 0 X-BIZMAIL-ID: 15633203404087285430 From: Zhangjin Wu To: thomas@t-8ch.de, w@1wt.eu Cc: falcon@tinylab.org, arnd@arndb.de, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-riscv@lists.infradead.org Subject: [PATCH v1 04/11] tools/nolibc: arm: shrink _start with _start_c Date: Thu, 29 Jun 2023 02:55:48 +0800 Message-Id: <30376b12e786f10ac8735431c35bc629f92a7d32.1687976753.git.falcon@tinylab.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 X-QQ-SENDSIZE: 520 Feedback-ID: bizesmtp:tinylab.org:qybglogicsvrsz:qybglogicsvrsz3a-3 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Let's move most of the _start operations to _start_c(). Signed-off-by: Zhangjin Wu --- tools/include/nolibc/arch-arm.h | 42 ++++----------------------------- 1 file changed, 5 insertions(+), 37 deletions(-) diff --git a/tools/include/nolibc/arch-arm.h b/tools/include/nolibc/arch-arm.h index a2ea5756cef2..573f8fe31cee 100644 --- a/tools/include/nolibc/arch-arm.h +++ b/tools/include/nolibc/arch-arm.h @@ -183,49 +183,17 @@ _arg1; \ }) - -char **environ __attribute__((weak)); -const unsigned long *_auxv __attribute__((weak)); - /* startup code */ void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) __no_stack_protector _start(void) { __asm__ volatile ( #ifdef _NOLIBC_STACKPROTECTOR - "bl __stack_chk_init\n" /* initialize stack protector */ + "bl __stack_chk_init\n" /* initialize stack protector */ #endif - "pop {%r0}\n" /* argc was in the stack */ - "mov %r1, %sp\n" /* argv = sp */ - - "add %r2, %r0, $1\n" /* envp = (argc + 1) ... */ - "lsl %r2, %r2, $2\n" /* * 4 ... */ - "add %r2, %r2, %r1\n" /* + argv */ - "ldr %r3, 1f\n" /* r3 = &environ (see below) */ - "str %r2, [r3]\n" /* store envp into environ */ - - "mov r4, r2\n" /* search for auxv (follows NULL after last env) */ - "0:\n" - "mov r5, r4\n" /* r5 = r4 */ - "add r4, r4, #4\n" /* r4 += 4 */ - "ldr r5,[r5]\n" /* r5 = *r5 = *(r4-4) */ - "cmp r5, #0\n" /* and stop at NULL after last env */ - "bne 0b\n" - "ldr %r3, 2f\n" /* r3 = &_auxv (low bits) */ - "str r4, [r3]\n" /* store r4 into _auxv */ - - "mov %r3, $8\n" /* AAPCS : sp must be 8-byte aligned in the */ - "neg %r3, %r3\n" /* callee, and bl doesn't push (lr=pc) */ - "and %r3, %r3, %r1\n" /* so we do sp = r1(=sp) & r3(=-8); */ - "mov %sp, %r3\n" - - "bl main\n" /* main() returns the status code, we'll exit with it. */ - "movs r7, $1\n" /* NR_exit == 1 */ - "svc $0x00\n" - ".align 2\n" /* below are the pointers to a few variables */ - "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(); }