From mboxrd@z Thu Jan 1 00:00:00 1970 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 460C0C19F28 for ; Wed, 3 Aug 2022 14:06:28 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id B73E62AE6F; Wed, 3 Aug 2022 14:06:17 +0000 (UTC) Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by gabe.freedesktop.org (Postfix) with ESMTPS id 9C2392AB20; Wed, 3 Aug 2022 14:06:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1659535560; x=1691071560; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version:content-transfer-encoding; bh=34VL+dhIeVMzhLZ89miUYPbPdIYYdh9192LOywXQAJs=; b=hgdsAsAAMnGgX84X8Mi/yLNH/qSM8ZL89cCM1yMF1GI4H8hDJWHFGLqs wXZXES9+jmowzwLjT/Bgq/i8n1t3GZnMHIqWPNXVSrAF3/U1ksnEr4ZQf 08DLBmpTJ5VlYUPTgvOEOtRrXm51hrg2GY9+2m23z+vcW9zJGtvM5ZQxl qKetmVP6TaGBDvKilcd7srfK6IydYTDbdz5vlnqJxLqhuGqHlxkLC0U8y 37zFj8crWXmLNX8SnY0yHj6chnpunjW5aekskYSNH83NwJPKqqWH2VUXk iyROM5IG/S/ZRtUmNx/jpFHb57eU3yJp5bZWawdbakEi4BRvBdtERf9Hf g==; X-IronPort-AV: E=McAfee;i="6400,9594,10428"; a="289689983" X-IronPort-AV: E=Sophos;i="5.93,214,1654585200"; d="scan'208";a="289689983" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Aug 2022 07:05:49 -0700 X-IronPort-AV: E=Sophos;i="5.93,214,1654585200"; d="scan'208";a="631161030" Received: from ns1-mobl.gar.corp.intel.com (HELO localhost) ([10.252.59.244]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Aug 2022 07:05:44 -0700 From: Jani Nikula To: Andi Shyti , Gwan-gyeong Mun Subject: Re: [Intel-gfx] [PATCH v5 1/7] drm: Move and add a few utility macros into drm util header In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20220725092528.1281487-1-gwan-gyeong.mun@intel.com> <20220725092528.1281487-2-gwan-gyeong.mun@intel.com> Date: Wed, 03 Aug 2022 17:05:41 +0300 Message-ID: <875yj9qv62.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: thomas.hellstrom@linux.intel.com, Tvrtko Ursulin , airlied@linux.ie, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, chris@chris-wilson.co.uk, matthew.auld@intel.com, Thomas Zimmermann , mchehab@kernel.org, nirmoy.das@intel.com Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Wed, 27 Jul 2022, Andi Shyti wrote: > Hi, > > On Mon, Jul 25, 2022 at 12:25:22PM +0300, Gwan-gyeong Mun wrote: >> It moves overflows_type utility macro into drm util header from i915_uti= ls >> header. The overflows_type can be used to catch the truncation between d= ata >> types. And it adds safe_conversion() macro which performs a type convers= ion >> (cast) of an source value into a new variable, checking that the >> destination is large enough to hold the source value. >> And it adds exact_type and exactly_pgoff_t macro to catch type mis-match >> while compiling. >>=20 >> v3: Add is_type_unsigned() macro (Mauro) >> Modify overflows_type() macro to consider signed data types (Mauro) >> Fix the problem that safe_conversion() macro always returns true >> v4: Fix kernel-doc markups >>=20 >> Signed-off-by: Gwan-gyeong Mun >> Cc: Thomas Hellstr=C3=B6m >> Cc: Matthew Auld >> Cc: Nirmoy Das >> Cc: Jani Nikula >> Reviewed-by: Mauro Carvalho Chehab >> --- >> drivers/gpu/drm/i915/i915_utils.h | 5 +- >> include/drm/drm_util.h | 77 +++++++++++++++++++++++++++++++ >> 2 files changed, 78 insertions(+), 4 deletions(-) > > Jani and Mauro suggested to have this macro in > include/drm/drm_util.h. I can't recall suggesting such a thing. The macros in question have nothing specifically to do with i915 *or* drm. They are generic, and should be in generic kernel headers. We must stop piling up generic and generally useful stuff in our own headers. I thought I've been clear about this all along. BR, Jani. > > Can I please have an ack from one of the drm maintainers so that > I can go ahead an apply this series? > > Thanks, > Andi > >>=20 >> diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i9= 15_utils.h >> index c10d68cdc3ca..345e5b2dc1cd 100644 >> --- a/drivers/gpu/drm/i915/i915_utils.h >> +++ b/drivers/gpu/drm/i915/i915_utils.h >> @@ -32,6 +32,7 @@ >> #include >> #include >> #include >> +#include >>=20=20 >> #ifdef CONFIG_X86 >> #include >> @@ -111,10 +112,6 @@ bool i915_error_injected(void); >> #define range_overflows_end_t(type, start, size, max) \ >> range_overflows_end((type)(start), (type)(size), (type)(max)) >>=20=20 >> -/* Note we don't consider signbits :| */ >> -#define overflows_type(x, T) \ >> - (sizeof(x) > sizeof(T) && (x) >> BITS_PER_TYPE(T)) >> - >> #define ptr_mask_bits(ptr, n) ({ \ >> unsigned long __v =3D (unsigned long)(ptr); \ >> (typeof(ptr))(__v & -BIT(n)); \ >> diff --git a/include/drm/drm_util.h b/include/drm/drm_util.h >> index 79952d8c4bba..1de9ee5704fa 100644 >> --- a/include/drm/drm_util.h >> +++ b/include/drm/drm_util.h >> @@ -62,6 +62,83 @@ >> */ >> #define for_each_if(condition) if (!(condition)) {} else >>=20=20 >> +/** >> + * is_type_unsigned - helper for checking data type which is an unsigne= d data >> + * type or not >> + * @x: The data type to check >> + * >> + * Returns: >> + * True if the data type is an unsigned data type, false otherwise. >> + */ >> +#define is_type_unsigned(x) ((typeof(x))-1 >=3D (typeof(x))0) >> + >> +/** >> + * overflows_type - helper for checking the truncation between data typ= es >> + * @x: Source for overflow type comparison >> + * @T: Destination for overflow type comparison >> + * >> + * It compares the values and size of each data type between the first = and >> + * second argument to check whether truncation can occur when assigning= the >> + * first argument to the variable of the second argument. >> + * Source and Destination can be used with or without sign bit. >> + * Composite data structures such as union and structure are not consid= ered. >> + * Enum data types are not considered. >> + * Floating point data types are not considered. >> + * >> + * Returns: >> + * True if truncation can occur, false otherwise. >> + */ >> + >> +#define overflows_type(x, T) \ >> + (is_type_unsigned(x) ? \ >> + is_type_unsigned(T) ? \ >> + (sizeof(x) > sizeof(T) && (x) >> BITS_PER_TYPE(T)) ? 1 : 0 \ >> + : (sizeof(x) >=3D sizeof(T) && (x) >> (BITS_PER_TYPE(T) - 1)) ? 1 : = 0 \ >> + : is_type_unsigned(T) ? \ >> + ((x) < 0) ? 1 : (sizeof(x) > sizeof(T) && (x) >> BITS_PER_TYPE(T)) ? = 1 : 0 \ >> + : (sizeof(x) > sizeof(T)) ? \ >> + ((x) < 0) ? (((x) * -1) >> BITS_PER_TYPE(T)) ? 1 : 0 \ >> + : ((x) >> BITS_PER_TYPE(T)) ? 1 : 0 \ >> + : 0) >> + >> +/** >> + * exact_type - break compile if source type and destination value's ty= pe are >> + * not the same >> + * @T: Source type >> + * @n: Destination value >> + * >> + * It is a helper macro for a poor man's -Wconversion: only allow varia= bles of >> + * an exact type. It determines whether the source type and destination= value's >> + * type are the same while compiling, and it breaks compile if two type= s are >> + * not the same >> + */ >> +#define exact_type(T, n) \ >> + BUILD_BUG_ON(!__builtin_constant_p(n) && !__builtin_types_compatible_p= (T, typeof(n))) >> + >> +/** >> + * exactly_pgoff_t - helper to check if the type of a value is pgoff_t >> + * @n: value to compare pgoff_t type >> + * >> + * It breaks compile if the argument value's type is not pgoff_t type. >> + */ >> +#define exactly_pgoff_t(n) exact_type(pgoff_t, n) >> + >> +/** >> + * safe_conversion - perform a type conversion (cast) of an source valu= e into >> + * a new variable, checking that the destination is large enough to hol= d the >> + * source value. >> + * @ptr: Destination pointer address >> + * @value: Source value >> + * >> + * Returns: >> + * If the value would overflow the destination, it returns false. >> + */ >> +#define safe_conversion(ptr, value) ({ \ >> + typeof(value) __v =3D (value); \ >> + typeof(ptr) __ptr =3D (ptr); \ >> + overflows_type(__v, *__ptr) ? 0 : ((*__ptr =3D (typeof(*__ptr))__v), 1= ); \ >> +}) >> + >> /** >> * drm_can_sleep - returns true if currently okay to sleep >> * >> --=20 >> 2.34.1 --=20 Jani Nikula, Intel Open Source Graphics Center