From patchwork Wed Jul 12 09:22:00 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhangjin Wu X-Patchwork-Id: 13309910 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 BACD7EB64DA for ; Wed, 12 Jul 2023 09:28:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229529AbjGLJ2w (ORCPT ); Wed, 12 Jul 2023 05:28:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44518 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232142AbjGLJ2u (ORCPT ); Wed, 12 Jul 2023 05:28:50 -0400 Received: from bg4.exmail.qq.com (bg4.exmail.qq.com [43.154.54.12]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E1546139; Wed, 12 Jul 2023 02:28:48 -0700 (PDT) X-QQ-mid: bizesmtp64t1689153721th57ji5d Received: from linux-lab-host.localdomain ( [116.30.126.249]) by bizesmtp.qq.com (ESMTP) with id ; Wed, 12 Jul 2023 17:22:00 +0800 (CST) X-QQ-SSF: 01200000000000D0W000000A0000000 X-QQ-FEAT: ILHsT53NKPjtB6FRZNFER3rcR7JDnPatbvx5VZiH7Ka3nO5WQOLWEFZpPEe8B Yg20t6QwyoFCV7b02MyegxMbyGupz2otIOof0G6QMVqebibWpCYSMNtwV2M05N2VPvYciuL jF5v/Go5WOVHowGe5VRc1vEC41oiM+YrlHt+5weearunvpqX1+GxfH0v7Syit0E+URdtohu 9hwfCZcaKT3NdX/a/Ps8iFWFV2qcRE0U7fuz5iTPfe/tlJk3Xw30z1Y2BGkAYdt8EwEnHr+ 1D/z5iJXvKaMQlS54kqs6mjGkWD1h3QFRBbwa6cUKarbLnaykhdxAmgGnkbFZy0WopMoW+8 apB15xrFXXrVeJf4imx2XhfhUHdkT8KcK0gALHVxGN9UEKsEoDXvi4foD2v5W+1himpDZ7d X-QQ-GoodBg: 0 X-BIZMAIL-ID: 13879264576707349728 From: Zhangjin Wu To: w@1wt.eu Cc: falcon@tinylab.org, arnd@arndb.de, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, thomas@t-8ch.de Subject: [PATCH v3 06/11] tools/nolibc: x86_64: shrink _start with _start_c Date: Wed, 12 Jul 2023 17:22:00 +0800 Message-Id: <8bdc96799300a5c5a40320d4f66ad54e97b4b9de.1689150149.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:qybglogicsvrgz:qybglogicsvrgz5a-1 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org move most of the _start operations to _start_c(). Signed-off-by: Zhangjin Wu --- tools/include/nolibc/arch-x86_64.h | 28 +++++++--------------------- 1 file changed, 7 insertions(+), 21 deletions(-) diff --git a/tools/include/nolibc/arch-x86_64.h b/tools/include/nolibc/arch-x86_64.h index e980ca5417d0..0048adf6b11f 100644 --- a/tools/include/nolibc/arch-x86_64.h +++ b/tools/include/nolibc/arch-x86_64.h @@ -8,6 +8,7 @@ #define _NOLIBC_ARCH_X86_64_H #include "compiler.h" +#include "crt.h" /* Syscalls for x86_64 : * - registers are 64-bit @@ -153,9 +154,6 @@ _ret; \ }) -char **environ __attribute__((weak)); -const unsigned long *_auxv __attribute__((weak)); - /* startup code */ /* * x86-64 System V ABI mandates: @@ -167,25 +165,13 @@ void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) __no_stack_pr { __asm__ volatile ( #ifdef _NOLIBC_STACKPROTECTOR - "call __stack_chk_init\n" /* initialize stack protector */ + "call __stack_chk_init\n" /* initialize stack protector */ #endif - "pop %rdi\n" /* argc (first arg, %rdi) */ - "mov %rsp, %rsi\n" /* argv[] (second arg, %rsi) */ - "lea 8(%rsi,%rdi,8),%rdx\n" /* then a NULL then envp (third arg, %rdx) */ - "mov %rdx, environ\n" /* save environ */ - "xor %ebp, %ebp\n" /* zero the stack frame */ - "mov %rdx, %rax\n" /* search for auxv (follows NULL after last env) */ - "0:\n" - "add $8, %rax\n" /* search for auxv using rax, it follows the */ - "cmp -8(%rax), %rbp\n" /* ... NULL after last env (rbp is zero here) */ - "jnz 0b\n" - "mov %rax, _auxv\n" /* save it into _auxv */ - "and $-16, %rsp\n" /* x86 ABI : esp must be 16-byte aligned before call */ - "call main\n" /* main() returns the status code, we'll exit with it. */ - "mov %eax, %edi\n" /* retrieve exit code (32 bit) */ - "mov $60, %eax\n" /* NR_exit == 60 */ - "syscall\n" /* really exit */ - "hlt\n" /* ensure it does not return */ + "xor %ebp, %ebp\n" /* zero the stack frame */ + "mov %rsp, %rdi\n" /* save stack pointer to %rdi, as arg1 of _start_c */ + "and $-16, %rsp\n" /* %rsp must be 16-byte aligned before call */ + "call _start_c\n" /* transfer to c runtime */ + "hlt\n" /* ensure it does not return */ ); __builtin_unreachable(); }