From nobody Tue Dec 16 19:22:12 2025 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 A2E8CE92722 for ; Thu, 5 Oct 2023 16:15:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241404AbjJEQOW convert rfc822-to-8bit (ORCPT ); Thu, 5 Oct 2023 12:14:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55196 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236597AbjJEQMZ (ORCPT ); Thu, 5 Oct 2023 12:12:25 -0400 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.85.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 361C53242 for ; Thu, 5 Oct 2023 07:40:28 -0700 (PDT) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with both STARTTLS and AUTH (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-306-jLh_EL-5Md2BLsfBL2-SBA-1; Thu, 05 Oct 2023 12:39:56 +0100 X-MC-Unique: jLh_EL-5Md2BLsfBL2-SBA-1 Received: from AcuMS.Aculab.com (10.202.163.6) by AcuMS.aculab.com (10.202.163.6) with Microsoft SMTP Server (TLS) id 15.0.1497.48; Thu, 5 Oct 2023 12:39:54 +0100 Received: from AcuMS.Aculab.com ([::1]) by AcuMS.aculab.com ([::1]) with mapi id 15.00.1497.048; Thu, 5 Oct 2023 12:39:54 +0100 From: David Laight To: "linux-kernel@vger.kernel.org" CC: "'linux@rasmusvillemoes.dk'" , 'Steven Rostedt' , "keescook@chromium.org" , "'bvanassche@acm.org'" , "torvalds@linux-foundation.org" , Nathan Chancellor , "Nick Desaulniers" , Arnd Bergmann , "akpm@linux-foundation.org" Subject: [PATCH v2 next] compiler.h: Move __is_constexpr() to compiler.h. Thread-Topic: [PATCH v2 next] compiler.h: Move __is_constexpr() to compiler.h. Thread-Index: Adn3gDrI19XXJwgHQoKm/0Q5RNmGHA== Date: Thu, 5 Oct 2023 11:39:54 +0000 Message-ID: <2a6680bbe2e84459816a113730426782@AcuMS.aculab.com> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Prior to f747e6667ebb2 __is_constexpr() was in its only user minmax.h. That commit moved it to const.h - but that file just defines ULL(x) and UL(x) so that constants can be defined for .S and .c files. So apart from the word 'const' it wasn't really a good location. Instead move the definition to compiler.h just before the similar is_signed_type() and is_unsigned_type(). This may not be a good long-term home, but the three definitions belong together. Signed-off-by: David Laight Reviewed-by: Kees Cook --- This makes it possible to use __is_constexpr() inside is_signed_type() so that the result is constant integer expression for pointer types. In particular (void *)1 isn't constant enough. v2: Add a copy into tools/linux/compiler.h to fix perf build. include/linux/compiler.h | 8 ++++++++ include/linux/const.h | 8 -------- tools/include/linux/compiler.h | 8 ++++++++ tools/include/linux/const.h | 8 -------- 4 files changed, 16 insertions(+), 16 deletions(-) diff --git a/include/linux/compiler.h b/include/linux/compiler.h index d7779a18b24f..2efec9bfcc40 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -230,6 +230,14 @@ static inline void *offset_to_ptr(const int *off) /* &a[0] degrades to a pointer: a different type from an array */ #define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0])) =20 +/* + * This returns a constant expression while determining if an argument is + * a constant expression, most importantly without evaluating the argument. + * Glory to Martin Uecker + */ +#define __is_constexpr(x) \ + (sizeof(int) =3D=3D sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8))) + /* * Whether 'type' is a signed type or an unsigned type. Supports scalar ty= pes, * bool and also pointer types. diff --git a/include/linux/const.h b/include/linux/const.h index 435ddd72d2c4..81b8aae5a855 100644 --- a/include/linux/const.h +++ b/include/linux/const.h @@ -3,12 +3,4 @@ =20 #include =20 -/* - * This returns a constant expression while determining if an argument is - * a constant expression, most importantly without evaluating the argument. - * Glory to Martin Uecker - */ -#define __is_constexpr(x) \ - (sizeof(int) =3D=3D sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8))) - #endif /* _LINUX_CONST_H */ diff --git a/tools/include/linux/compiler.h b/tools/include/linux/compiler.h index 1684216e826a..7b65566f3e42 100644 --- a/tools/include/linux/compiler.h +++ b/tools/include/linux/compiler.h @@ -63,6 +63,14 @@ # define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(= b)) #endif =20 +/* + * This returns a constant expression while determining if an argument is + * a constant expression, most importantly without evaluating the argument. + * Glory to Martin Uecker + */ +#define __is_constexpr(x) \ + (sizeof(int) =3D=3D sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8))) + #ifdef __ANDROID__ /* * FIXME: Big hammer to get rid of tons of: diff --git a/tools/include/linux/const.h b/tools/include/linux/const.h index 435ddd72d2c4..81b8aae5a855 100644 --- a/tools/include/linux/const.h +++ b/tools/include/linux/const.h @@ -3,12 +3,4 @@ =20 #include =20 -/* - * This returns a constant expression while determining if an argument is - * a constant expression, most importantly without evaluating the argument. - * Glory to Martin Uecker - */ -#define __is_constexpr(x) \ - (sizeof(int) =3D=3D sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8))) - #endif /* _LINUX_CONST_H */ --=20 2.17.1 - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1= PT, UK Registration No: 1397386 (Wales)