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 841E3C19F2A for ; Thu, 11 Aug 2022 16:31:01 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0306B14B581; Thu, 11 Aug 2022 16:30:29 +0000 (UTC) Received: from mail-wr1-x442.google.com (mail-wr1-x442.google.com [IPv6:2a00:1450:4864:20::442]) by gabe.freedesktop.org (Postfix) with ESMTPS id 90D7311BC18 for ; Thu, 11 Aug 2022 16:30:03 +0000 (UTC) Received: by mail-wr1-x442.google.com with SMTP id q30so21891160wra.11 for ; Thu, 11 Aug 2022 09:30:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc; bh=ITtAJcrSKONLpgdP6wxvcE20Pk/3Hh/rYW7aksLpJc0=; b=BDrwJasWMBs6cmx9rHlyJz0Kqh1UmW0yFutp42uJJHfYeRXvevqQEZgR2Epibr9i25 I+HvJUrPcvW2/x7lXaYBQNgfar2of3LCr98v2JtG4de9pg24t5+cicIU1nOOngXAi1e+ U8oTsy7ndJrDwQ+5NaV7nGAka4c3BWC1rO6Lg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc; bh=ITtAJcrSKONLpgdP6wxvcE20Pk/3Hh/rYW7aksLpJc0=; b=wL5GP/6cONvUcrLzWFocFYZwZWYOB1G7NW607LeFmRt7BnADPjYaW1x2eZZZuTSk7k /pqYC8ddrDCxQ4FvrTVi04shOQsHvDSkKCtOjT1GreTPdQRtz+8HewlYJZ8zVPLEe2vL E2OWjR0YWQ5teHo2kh+AWIljU00hoUTN8HZEwGXcD4KXEAcdrSnTLGLmC7nh4IHpItyg XtOjhILZY4T2hGTpoBANRn/GdXV37Y4MLfqO2tVRT576Ka6hGoqxiQ9tN5rMj5A42TWZ OzAKsDrNMHbfAH9N5oKt2rARmBQtFNQ5tnn8l1yoaifGo73wlkJxVXEQ1eflhlZ/kEhe N12w== X-Gm-Message-State: ACgBeo0l/TPwh7+Q6IMyXFInQgNHSR4cp8Mi6lNLVLoM8AMwBRXfSz8B HEwEIeESLGBixuKbpLmw8FN0Hw== X-Google-Smtp-Source: AA6agR4KnOYFTCKJ78QmLw/epN/mbQZWXQt4WyNk4qxklKYjBqw79OujrvuOo9UUYKRBmDghh+TnXA== X-Received: by 2002:a5d:6348:0:b0:220:5edf:c3e8 with SMTP id b8-20020a5d6348000000b002205edfc3e8mr20612709wrw.255.1660235401863; Thu, 11 Aug 2022 09:30:01 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id f19-20020a05600c4e9300b003a30fbde91dsm8077311wmq.20.2022.08.11.09.30.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 11 Aug 2022 09:30:01 -0700 (PDT) Date: Thu, 11 Aug 2022 18:29:59 +0200 From: Daniel Vetter To: Gwan-gyeong Mun Message-ID: References: <20220719140424.430572-1-gwan-gyeong.mun@intel.com> <20220719140424.430572-2-gwan-gyeong.mun@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220719140424.430572-2-gwan-gyeong.mun@intel.com> X-Operating-System: Linux phenom 5.10.0-8-amd64 Subject: Re: [Intel-gfx] [PATCH v4 1/7] drm: Move and add a few utility macros into drm util header X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: thomas.hellstrom@linux.intel.com, jani.nikula@intel.com, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, chris@chris-wilson.co.uk, airlied@linux.ie, matthew.auld@intel.com, daniel@ffwll.ch, mchehab@kernel.org, nirmoy.das@intel.com Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Tue, Jul 19, 2022 at 05:04:18PM +0300, Gwan-gyeong Mun wrote: > It moves overflows_type utility macro into drm util header from i915_utils > header. The overflows_type can be used to catch the truncation between data > types. And it adds safe_conversion() macro which performs a type conversion > (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. > > 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 > > Signed-off-by: Gwan-gyeong Mun > Cc: Thomas Hellström > 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 +++++++++++++++++++++++++++++++ It's nice that there's less random piling into i915_utils.h, but pushing them into drm_util.h isn't really better. These should all be in include/linux/ somewhere, so that we have as consistent code as possible. drm_util.h should only be a fallback if we get nacks for a more general place and still think it's the right thing to do. i915_util.h has frankyl gone completely bonkers and should die. -Daniel > 2 files changed, 78 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_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 > > #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)) > > -/* 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 = (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 > > +/** > + * is_type_unsigned - helper for checking data type which is an unsigned 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 >= (typeof(x))0) > + > +/** > + * overflows_type - helper for checking the truncation between data types > + * @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 considered. > + * 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) >= 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 type are > + * not the same > + * @T: Source type > + * @n: Destination value > + * > + * It is a helper macro for a poor man's -Wconversion: only allow variables 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 types 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 value into > + * a new variable, checking that the destination is large enough to hold 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 = (value); \ > + typeof(ptr) __ptr = (ptr); \ > + overflows_type(__v, *__ptr) ? 0 : ((*__ptr = (typeof(*__ptr))__v), 1); \ > +}) > + > /** > * drm_can_sleep - returns true if currently okay to sleep > * > -- > 2.34.1 > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch