From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EE5B28C05; Mon, 1 May 2023 21:37:16 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 136E3C433EF; Mon, 1 May 2023 21:37:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1682977036; bh=TbwlViufFEIhz3VjcV/zsYukgrEOYlIWPd8kMF7ZOAY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UFNAAZ9nrBeaF3tgZeYaqqEQpYgwoyjHjmvnIMcFG0grdmMeprfiFu0p6c2L0g7vX hyqiLsPFowrvFMUdnvb75U0RKCgh1mc+zdCTPIFyz8L1H7bMJFOCUG/Rdkuqq5CcZu mpbz5vYQlOD1iVAkc3J4uHXAKbE8o3s7zOdNy83eOX/bAFPR8TrjqgcuCeJkwxpQIc RiPu4PaLycuFYNkduFMc0ZWhqG03fgxrUdsV2Xu6X4NcxaS+F3DFs/PBlx2AUuLWaL nHQJ9AUgQ9vHv1VEKC0gFMa0/TzLRESDZOWn3xnWwD8m30+P/GXm7zKdRKxPFlDWrs wgxATUjy2UYxw== Date: Mon, 1 May 2023 14:37:14 -0700 From: Nathan Chancellor To: qinjian@cqplus1.com, mturquette@baylibre.com, sboyd@kernel.org Cc: ndesaulniers@google.com, trix@redhat.com, linux-arm-kernel@lists.infradead.org, linux-clk@vger.kernel.org, llvm@lists.linux.dev, patches@lists.linux.dev Subject: Re: [PATCH] clk: sp7021: Adjust width of _m in HWM_FIELD_PREP() Message-ID: <20230501213714.GA1007102@dev-arch.thelio-3990X> References: <20230501-sp7021-field_prep-warning-v1-1-5b36d71feefe@kernel.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230501-sp7021-field_prep-warning-v1-1-5b36d71feefe@kernel.org> On Mon, May 01, 2023 at 02:34:47PM -0700, Nathan Chancellor wrote: > When building with clang + W=1, there is a warning around an internal > comparison check within the FIELD_PREP() macro, due to a 32-bit variable > comparison against ~0ull: > > drivers/clk/clk-sp7021.c:316:8: error: result of comparison of constant 18446744073709551615 with expression of type 'typeof (_Generic((_m), ...' (aka 'unsigned int') is always false [-Werror,-Wtautological-constant-out-of-range-compare] > r0 |= HWM_FIELD_PREP(MASK_SEL_FRA, clk->p[SEL_FRA]); > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > drivers/clk/clk-sp7021.c:45:15: note: expanded from macro 'HWM_FIELD_PREP' > (_m << 16) | FIELD_PREP(_m, value); \ > ^~~~~~~~~~~~~~~~~~~~~ > include/linux/bitfield.h:114:3: note: expanded from macro 'FIELD_PREP' > __BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: "); \ > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > include/linux/bitfield.h:71:53: note: expanded from macro '__BF_FIELD_CHECK' > BUILD_BUG_ON_MSG(__bf_cast_unsigned(_mask, _mask) > \ > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~ > note: (skipping 1 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all) > include/linux/compiler_types.h:397:22: note: expanded from macro 'compiletime_assert' > _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) > ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > include/linux/compiler_types.h:385:23: note: expanded from macro '_compiletime_assert' > __compiletime_assert(condition, msg, prefix, suffix) > ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > include/linux/compiler_types.h:377:9: note: expanded from macro '__compiletime_assert' > if (!(condition)) \ > ^~~~~~~~~ > > This is expected given the tyoes of the input. Increase the size of the > temporary variable in HWM_FIELD_PREP() to eliminate the warning, which > follows the logic of commit cfd6fb45cfaf ("crypto: ccree - avoid > out-of-range warnings from clang") for the same reasons. Gah, I forgot: Reported-by: kernel test robot Link: https://lore.kernel.org/202303221947.pXP2v4xJ-lkp@intel.com/ > Signed-off-by: Nathan Chancellor > --- > drivers/clk/clk-sp7021.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/clk/clk-sp7021.c b/drivers/clk/clk-sp7021.c > index 8fec14120105..11d22043ddd7 100644 > --- a/drivers/clk/clk-sp7021.c > +++ b/drivers/clk/clk-sp7021.c > @@ -41,7 +41,7 @@ enum { > /* HIWORD_MASK FIELD_PREP */ > #define HWM_FIELD_PREP(mask, value) \ > ({ \ > - u32 _m = mask; \ > + u64 _m = mask; \ > (_m << 16) | FIELD_PREP(_m, value); \ > }) > > > --- > base-commit: d54c1fd4a51e8fbc7f9da86b0cd338a4f7cd2bb2 > change-id: 20230501-sp7021-field_prep-warning-223f17aeea8e > > Best regards, > -- > Nathan Chancellor >