From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934419AbbGVObk (ORCPT ); Wed, 22 Jul 2015 10:31:40 -0400 Received: from mailgw02.mediatek.com ([210.61.82.184]:45253 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1752929AbbGVObj (ORCPT ); Wed, 22 Jul 2015 10:31:39 -0400 X-Listener-Flag: 11101 Message-ID: <1437575494.30329.80.camel@mtksdaap41> Subject: Re: [PATCH] regmap: Add function check before called format_val From: Henry Chen To: Mark Brown CC: Matthias Brugger , Sascha Hauer , , , , Date: Wed, 22 Jul 2015 22:31:34 +0800 In-Reply-To: <20150721172550.GY11162@sirena.org.uk> References: <1437396110-5192-1-git-send-email-henryc.chen@mediatek.com> <20150720150254.GC11162@sirena.org.uk> <1437458845.30329.51.camel@mtksdaap41> <20150721172550.GY11162@sirena.org.uk> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit MIME-Version: 1.0 X-MTK: N Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2015-07-21 at 18:25 +0100, Mark Brown wrote: > On Tue, Jul 21, 2015 at 02:07:25PM +0800, Henry Chen wrote: > > > Then in driver rtc-mt6397.c, it used regmap_bulk_read() to get the time > > of PMIC, and hit the null function of format_val(), because the > > regmap_bus was null. > > > It skipped the initialization of format_val() because bus == null, but > > called the format_val() at regmap_bulk_read() if bus == null. > > OK, so the issue here is that when we fall back to regmap_read() we may > do so because we have reg_read() and reg_write() functions which in turn > imply no formatting. The expectation here is that val must be an array > of int. The code doesn't completely take that into account though and > the user you're pointing at is assuming it's an array of 16 bit values > which isn't totally unreasonable if it did specify val_bits (we don't > check for that). So, could I call regmap_bulk_read() on rtc-mt6307.c, should I need to change it ? > > > Maybe it was not the good fix for this, but should be a problem need to > > be reported, or should I need to give the regmap_bus on mtk_pmic_wrap.c? > > That file isn't in mainline... oh...it's mtk-pmic-wrap.c, sorry about that. > > memcpy() is definitely not a safe way to move from an unsigned int to a > u16 which is what your specific use case is trying to do. I'll need to > do an audit of existing users (or someone else will!) to figure out what > people are doing with .val_bits in drivers using reg_read() and > reg_write() but I think what we should be doing here is probably > providing appropriate conversion functions based on val_bits on init. Ok, got it, memcpy() should not be used here anymore. Thanks, Henry