From patchwork Sat Jul 8 15:34:23 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhangjin Wu X-Patchwork-Id: 700691 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 B4271EB64DA for ; Sat, 8 Jul 2023 15:34:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229707AbjGHPeg (ORCPT ); Sat, 8 Jul 2023 11:34:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33498 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229436AbjGHPeg (ORCPT ); Sat, 8 Jul 2023 11:34:36 -0400 Received: from bg4.exmail.qq.com (bg4.exmail.qq.com [43.154.54.12]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3CDB3B9; Sat, 8 Jul 2023 08:34:34 -0700 (PDT) X-QQ-mid: bizesmtp71t1688830464t9qr84v5 Received: from linux-lab-host.localdomain ( [116.30.131.119]) by bizesmtp.qq.com (ESMTP) with id ; Sat, 08 Jul 2023 23:34:24 +0800 (CST) X-QQ-SSF: 01200000000000D0W000000A0000000 X-QQ-FEAT: RmDZc/K2LPGrTc+Pc4Z2+3faJnbCPSy2B/cQnsYjS8cIDt3lndFeaPYMb6dVv 66TIx8pcxIbgWY06emMhGeUkT53LMFTNGUbLANkvUosh4MvYKjoocDa18HkvXgsNohOk+wC bHUNoPa5KHa6/cZleWKjVTEjELQEGDzT+B8opn1vLcA6YjeBD7WDtm7FTeVzmGk63TiST8I 2DLzl8HMSz8vMBGSCp5wu+c+RHImsN+H+fHEVmNtVFYBYJWeu7B+Uj8q1FEAMEW3+OKO09B CbdCIUjolq+sJuYPJiNBmepGT44pYKlTR8q2AVDDxPAEg5RB5zUzTo1lOnrXhVaOEMncfIa i2eTVLw9VQkzBgX0cztOgs6mKU/Ygs8LVo2hYUa+iqsmYIM9dHPMwRLAsrR0A== X-QQ-GoodBg: 0 X-BIZMAIL-ID: 10461963764472987799 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 v2 08/12] tools/nolibc: x86_64/crt.h: shrink _start with _start_c Date: Sat, 8 Jul 2023 23:34:23 +0800 Message-Id: <190ba3df4d2be93a220a8f83a902785adcc4c302.1688828139.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/x86_64/crt.h | 25 +++++++------------------ 1 file changed, 7 insertions(+), 18 deletions(-) diff --git a/tools/include/nolibc/x86_64/crt.h b/tools/include/nolibc/x86_64/crt.h index 6fede1235efc..03899042854e 100644 --- a/tools/include/nolibc/x86_64/crt.h +++ b/tools/include/nolibc/x86_64/crt.h @@ -18,27 +18,16 @@ void __attribute__((weak, noreturn, optimize("omit-frame-pointer"))) __no_stack_ { __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(); + } #endif /* _NOLIBC_X86_64_CRT_H */