From patchwork Sun Aug 6 13:19:21 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhangjin Wu X-Patchwork-Id: 13342865 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 A206DC0015E for ; Sun, 6 Aug 2023 13:19:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229804AbjHFNTy (ORCPT ); Sun, 6 Aug 2023 09:19:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40238 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229456AbjHFNTx (ORCPT ); Sun, 6 Aug 2023 09:19:53 -0400 Received: from smtpbgbr1.qq.com (smtpbgbr1.qq.com [54.207.19.206]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 60794C2; Sun, 6 Aug 2023 06:19:48 -0700 (PDT) X-QQ-mid: bizesmtp72t1691327963tr1qoydy Received: from linux-lab-host.localdomain ( [116.30.130.12]) by bizesmtp.qq.com (ESMTP) with id ; Sun, 06 Aug 2023 21:19:22 +0800 (CST) X-QQ-SSF: 01200000000000E0X000000A0000000 X-QQ-FEAT: XBN7tc9DADJKBbB/ql4J8bBvYfS/azHKW14GrIV6vLK5ySQHWbnNnBacPvDLO ICwhImWR8bBZ1or77Lsl/kjVP8EFcLGvYdeJDKDif0vCa339U+RWYYTRYrNhZUQv33c3Lbg 1BWBw1/MOWa63+wrTwizBYz5vTNFm3Fh9Bd6gomP82xMpocbreTrUiKL5GuQagQo9hotAK/ 6CTQJM2tZao5o6pRRPdyLlO1h0jE/EPxe6ofXiKZN+Q2trDR0MAlI/GI+UogqYJQ/4U0UOY LZopFgttnL463Y50MiCXRRYJDUa5ELgbZec4BUgAVaAnTIUyS3EYDh6LOruREFOdJpC9yIM CXwRV8BkzMIoe6UIbzE6SCufCDxpRQbytFtLwGHhExY2VaI3blmtWd8B1XWCBMcjVIFRI/h iz+NnCgRbyg= X-QQ-GoodBg: 0 X-BIZMAIL-ID: 14233024139879409729 From: Zhangjin Wu To: w@1wt.eu Cc: arnd@arndb.de, david.laight@aculab.com, falcon@tinylab.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, thomas@t-8ch.de Subject: [PATCH] tools/nolibc: fix up size inflate regression Date: Sun, 6 Aug 2023 21:19:21 +0800 Message-Id: <20230806131921.52453-1-falcon@tinylab.org> X-Mailer: git-send-email 2.25.1 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 As reported and suggested by Willy, the inline __sysret() helper introduces three types of conversions and increases the size: (1) the "unsigned long" argument to __sysret() forces a sign extension from all sys_* functions that used to return 'int' (2) the comparison with the error range now has to be performed on a 'unsigned long' instead of an 'int' (3) the return value from __sysret() is a 'long' (note, a signed long) which then has to be turned back to an 'int' before being returned by the caller to satisfy the caller's prototype. To fix up this, firstly, let's use macro instead of inline function to preserves the input type and avoids these useless conversions (1), (3). Secondly, comparison to -MAX_ERRNO inflicts on all integer returns where we could previously keep a simple sign comparison, let's use a new is_signed_type() macro from include/linux/compiler.h to limit the comparision to -MAX_ERRNO (2) only on demand and preserves a simple sign comparision for most of the cases as before. Thirdly, fix up the following warning by an explicit conversion: sysroot/powerpc/include/sys.h: In function 'sbrk': sysroot/powerpc/include/sys.h:104:16: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast] 104 | return (void *)__sysret(-ENOMEM); Here reports the size testing result with nolibc-test: before: // ppc64le $ size nolibc-test text data bss dec hex filename 27916 8 80 28004 6d64 nolibc-test // mips $ size nolibc-test text data bss dec hex filename 23276 64 64 23404 5b6c nolibc-test after: // ppc64le $ size nolibc-test text data bss dec hex filename 27736 8 80 27824 6cb0 nolibc-test // mips $ size nolibc-test text data bss dec hex filename 23036 64 64 23164 5a7c nolibc-test Suggested-by: Willy Tarreau Link: https://lore.kernel.org/lkml/20230806095846.GB10627@1wt.eu/#R Signed-off-by: Zhangjin Wu --- tools/include/nolibc/compiler.h | 9 +++++++++ tools/include/nolibc/sys.h | 27 +++++++++++++++++---------- 2 files changed, 26 insertions(+), 10 deletions(-) diff --git a/tools/include/nolibc/compiler.h b/tools/include/nolibc/compiler.h index beddc3665d69..360dfc533814 100644 --- a/tools/include/nolibc/compiler.h +++ b/tools/include/nolibc/compiler.h @@ -22,4 +22,13 @@ # define __no_stack_protector __attribute__((__optimize__("-fno-stack-protector"))) #endif /* defined(__has_attribute) */ +/* + * from include/linux/compiler.h + * + * Whether 'type' is a signed type or an unsigned type. Supports scalar types, + * bool and also pointer types. + */ +#define is_signed_type(type) (((type)(-1)) < (type)1) +#define is_unsigned_type(type) (!is_signed_type(type)) + #endif /* _NOLIBC_COMPILER_H */ diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h index 56f63eb48a1b..8271302f79c4 100644 --- a/tools/include/nolibc/sys.h +++ b/tools/include/nolibc/sys.h @@ -35,15 +35,22 @@ * (src/internal/syscall_ret.c) and glibc (sysdeps/unix/sysv/linux/sysdep.h) */ -static __inline__ __attribute__((unused, always_inline)) -long __sysret(unsigned long ret) -{ - if (ret >= (unsigned long)-MAX_ERRNO) { - SET_ERRNO(-(long)ret); - return -1; - } - return ret; -} +#define __sysret(arg) \ +({ \ + __typeof__(arg) __sysret_arg = (arg); \ + if (is_signed_type(__typeof__(arg))) { \ + if (__sysret_arg < 0) { \ + SET_ERRNO(-(int)__sysret_arg); \ + __sysret_arg = -1L; \ + } \ + } else { \ + if ((unsigned long)__sysret_arg >= (unsigned long)-MAX_ERRNO) { \ + SET_ERRNO(-(int)__sysret_arg); \ + __sysret_arg = -1L; \ + } \ + } \ + __sysret_arg; \ +}) /* Functions in this file only describe syscalls. They're declared static so * that the compiler usually decides to inline them while still being allowed @@ -94,7 +101,7 @@ void *sbrk(intptr_t inc) if (ret && sys_brk(ret + inc) == ret + inc) return ret + inc; - return (void *)__sysret(-ENOMEM); + return (void *)__sysret((unsigned long)-ENOMEM); }