From patchwork Wed Jun 28 18:59:59 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhangjin Wu X-Patchwork-Id: 13296153 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 549DEEB64D7 for ; Wed, 28 Jun 2023 19:01:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230512AbjF1TBS (ORCPT ); Wed, 28 Jun 2023 15:01:18 -0400 Received: from bg4.exmail.qq.com ([43.154.54.12]:35030 "EHLO bg4.exmail.qq.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232772AbjF1TAU (ORCPT ); Wed, 28 Jun 2023 15:00:20 -0400 X-QQ-mid: bizesmtp86t1687978810tf2ar9vw Received: from linux-lab-host.localdomain ( [116.30.129.193]) by bizesmtp.qq.com (ESMTP) with id ; Thu, 29 Jun 2023 03:00:08 +0800 (CST) X-QQ-SSF: 01200000000000D0W000000A0000000 X-QQ-FEAT: +ynUkgUhZJneCqf/WiFIlQeErW4hE9O+nEPddl2PRkjGlBZEniPrcbaTTc7s2 5f7+aA6vYP9PgLSC4T+j0tcUHwDVAnq8K7wx2MCiGSfUIbExALiKcxf1iKlDVqafqQCqd7u w6L2PnJbHsPLcw/lQuF2hvLgUlEij/5DAIfSAqE1oRd1Y5ZtWZoW+kxKtrEEg616wwLLjoF 3yRqaVk1PLD1I42O+doEPlLna5UF0Ob/6v7p7L7gjJVYrJVWrIr8SAIrcz/RsiRD27lBnl5 TElxw/lGgBlRGo6OFU0/aBHG2qDnPSoZHBD6UI8D2fq8Cje2g2Dm5BiBWqCmJr2l+N/eX6q xVeXxjtbPRXqoMegPcU9CcfyiG5e0xQGVdKth5kBBUlzsUSr6bbfGY2eD8fsg== X-QQ-GoodBg: 0 X-BIZMAIL-ID: 10657381781421926358 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 07/11] tools/nolibc: x86_64: shrink _start with _start_c Date: Thu, 29 Jun 2023 02:59:59 +0800 Message-Id: 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-x86_64.h | 27 ++++++--------------------- 1 file changed, 6 insertions(+), 21 deletions(-) diff --git a/tools/include/nolibc/arch-x86_64.h b/tools/include/nolibc/arch-x86_64.h index 4c0192815a59..116dcd8e1413 100644 --- a/tools/include/nolibc/arch-x86_64.h +++ b/tools/include/nolibc/arch-x86_64.h @@ -153,9 +153,6 @@ _ret; \ }) -char **environ __attribute__((weak)); -const unsigned long *_auxv __attribute__((weak)); - /* startup code */ /* * x86-64 System V ABI mandates: @@ -167,25 +164,13 @@ 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(); }