From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Boyd Subject: Sparse warnings on GENMASK + arm32 Date: Tue, 25 Jul 2017 18:30:20 -0700 Message-ID: <20170726013020.GL2146@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from smtp.codeaurora.org ([198.145.29.96]:60964 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751454AbdGZBaW (ORCPT ); Tue, 25 Jul 2017 21:30:22 -0400 Content-Disposition: inline Sender: linux-sparse-owner@vger.kernel.org List-Id: linux-sparse@vger.kernel.org To: linux-sparse@vger.kernel.org Cc: linux-kernel@vger.kernel.org I see sparse warning when I check a clk driver file in the kernel on a 32-bit ARM build. drivers/clk/sunxi/clk-sun6i-ar100.c:65:20: warning: cast truncates bits from constant value (3ffffffff becomes ffffffff) The code in question looks like: static const struct factors_data sun6i_ar100_data = { .mux = 16, .muxmask = GENMASK(1, 0), .table = &sun6i_ar100_config, .getter = sun6i_get_ar100_factors, }; where factors_data is struct factors_data { int enable; int mux; int muxmask; const struct clk_factors_config *table; void (*getter)(struct factors_request *req); void (*recalc)(struct factors_request *req); const char *name; }; and sparse seems to be complaining about the muxmask assignment here. Oddly, this doesn't happen on arm64 builds. Both times, I'm checking this on an x86-64 machine. $ sparse --version v0.5.1-rc4-1-gfa71b7ac0594 Is there something confusing to sparse in the GENMASK macro? -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project