From patchwork Wed Jun 28 19:01:14 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhangjin Wu X-Patchwork-Id: 13296154 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 872BBEB64D7 for ; Wed, 28 Jun 2023 19:02:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230387AbjF1TCP (ORCPT ); Wed, 28 Jun 2023 15:02:15 -0400 Received: from bg4.exmail.qq.com ([43.154.54.12]:18931 "EHLO bg4.exmail.qq.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232308AbjF1TBe (ORCPT ); Wed, 28 Jun 2023 15:01:34 -0400 X-QQ-mid: bizesmtp89t1687978884tr421dbg Received: from linux-lab-host.localdomain ( [116.30.129.193]) by bizesmtp.qq.com (ESMTP) with id ; Thu, 29 Jun 2023 03:01:22 +0800 (CST) X-QQ-SSF: 01200000000000D0W000000A0000000 X-QQ-FEAT: ILHsT53NKPjPXjqsNEc9WBpKx63aH6ekhXt41at7lejx0jr9AWFyR18ehAl08 bHwqwkh7ymPLXY51CXtEBbfJ81cFMb2N0GSZHiCmbuOThu+5KQkwU0LEAvuiO8wiXR40au+ 4X2xjRXPLeh32yf38Zo9qZZfNIKaLF8phJjBU3yxPar+YY8Q/0663gzWqLw6pqlfMnXWEA7 gTgLLrDNjI9hGBUWpUIFGbyjQcfZ0/DBlfkyKdyU4lJdu2IgREZqdq3GexHqZ7UxX9ULcnk 8Nwu5hA13KXbNIxvJoE4xEcbre+ivYBN/aw3H4A6wPt2RirdsH9F4qQv0RfGlMvp6PDRNlU Iev1qO3zLEoA/9++tmAJvh8F3qMV8zXatpRjX/HatGjBbl0UxI= X-QQ-GoodBg: 0 X-BIZMAIL-ID: 4007669029372385518 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 08/11] tools/nolibc: mips: shrink _start with _start_c Date: Thu, 29 Jun 2023 03:01:14 +0800 Message-Id: <0d650309e0cf79fee1a87995d3fcae083b96b150.1687976753.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(). Also clean up the instructions in delay slots. Signed-off-by: Zhangjin Wu --- tools/include/nolibc/arch-mips.h | 45 +++++++------------------------- 1 file changed, 9 insertions(+), 36 deletions(-) diff --git a/tools/include/nolibc/arch-mips.h b/tools/include/nolibc/arch-mips.h index ecf912a1938f..d0f73f03bfa1 100644 --- a/tools/include/nolibc/arch-mips.h +++ b/tools/include/nolibc/arch-mips.h @@ -173,50 +173,23 @@ _arg4 ? -_num : _num; \ }) -char **environ __attribute__((weak)); -const unsigned long *_auxv __attribute__((weak)); - /* startup code, note that it's called __start on MIPS */ void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) __no_stack_protector __start(void) { __asm__ volatile ( - /*".set nomips16\n"*/ ".set push\n" - ".set noreorder\n" + ".set noreorder\n" ".option pic0\n" #ifdef _NOLIBC_STACKPROTECTOR - "jal __stack_chk_init\n" /* initialize stack protector */ - "nop\n" /* delayed slot */ + "jal __stack_chk_init\n" /* initialize stack protector */ + " nop\n" /* delayed slot */ #endif - /*".ent __start\n"*/ - /*"__start:\n"*/ - "lw $a0,($sp)\n" /* argc was in the stack */ - "addiu $a1, $sp, 4\n" /* argv = sp + 4 */ - "sll $a2, $a0, 2\n" /* a2 = argc * 4 */ - "add $a2, $a2, $a1\n" /* envp = argv + 4*argc ... */ - "addiu $a2, $a2, 4\n" /* ... + 4 */ - "lui $a3, %hi(environ)\n" /* load environ into a3 (hi) */ - "addiu $a3, %lo(environ)\n" /* load environ into a3 (lo) */ - "sw $a2,($a3)\n" /* store envp(a2) into environ */ - - "move $t0, $a2\n" /* iterate t0 over envp, look for NULL */ - "0:" /* do { */ - "lw $a3, ($t0)\n" /* a3=*(t0); */ - "bne $a3, $0, 0b\n" /* } while (a3); */ - "addiu $t0, $t0, 4\n" /* delayed slot: t0+=4; */ - "lui $a3, %hi(_auxv)\n" /* load _auxv into a3 (hi) */ - "addiu $a3, %lo(_auxv)\n" /* load _auxv into a3 (lo) */ - "sw $t0, ($a3)\n" /* store t0 into _auxv */ - - "li $t0, -8\n" - "and $sp, $sp, $t0\n" /* sp must be 8-byte aligned */ - "addiu $sp,$sp,-16\n" /* the callee expects to save a0..a3 there! */ - "jal main\n" /* main() returns the status code, we'll exit with it. */ - "nop\n" /* delayed slot */ - "move $a0, $v0\n" /* retrieve 32-bit exit code from v0 */ - "li $v0, 4001\n" /* NR_exit == 4001 */ - "syscall\n" - /*".end __start\n"*/ + "move $a0, $sp\n" /* save stack pointer to a0, as arg1 of _start_c*/ + "li $t0, -8\n" + "and $sp, $sp, $t0\n" /* sp must be 8-byte aligned */ + "addiu $sp, $sp, -16\n" /* the callee expects to save a0..a3 there */ + "jal _start_c\n" /* transfer to c runtime */ + " nop\n" /* delayed slot */ ".set pop\n" ); __builtin_unreachable();