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 X-Spam-Level: X-Spam-Status: No, score=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 90F03C433E9 for ; Tue, 2 Mar 2021 18:12:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4EDCB64F1E for ; Tue, 2 Mar 2021 18:12:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350182AbhCBSIu (ORCPT ); Tue, 2 Mar 2021 13:08:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50496 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344087AbhCBP2W (ORCPT ); Tue, 2 Mar 2021 10:28:22 -0500 Received: from mail-pf1-x42e.google.com (mail-pf1-x42e.google.com [IPv6:2607:f8b0:4864:20::42e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 68A69C061A2B; Tue, 2 Mar 2021 06:56:54 -0800 (PST) Received: by mail-pf1-x42e.google.com with SMTP id i10so4825393pfk.4; Tue, 02 Mar 2021 06:56:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=U6T9PbU/F4qKp+N/YQtkVMfFVe3qnYSRW1k8rGsnvnk=; b=BBmSnXXr+94I6o1ekJr9V+ADvzDVATCFa7BccMr9FAJhc0gsyNi5pLeemmgdQhFhfL G9Mso1M/4bzUIVzexYT4ggJhMej38VIoGil1Z4SnggW/LKRm3OKV88h9RKKOh5p5XA5O 15quSskjfkQTAlyI23i8U7rTHirlIoRTfyHu7ICnbuk7HM83LI1wZX/A7EB0E2imd2iz xF1BKS8jaXgWQyxjgf6YgnoiNuZP93gDZhF0xpDURqMZulbVP9RkSeV+hYme0zfuYbLo qAF5kB1a3JMgNlJyYknLMlLknaZZX9TduHtqiGBBNyn8KNgdpoQ/dmniWSptZtW5/VNM am6w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=U6T9PbU/F4qKp+N/YQtkVMfFVe3qnYSRW1k8rGsnvnk=; b=W3YWnCH501pDu4+z9L8NDRWe0j3Z3tjOU1mZMpTL5KvV3j8Wh+LJkg1GgT/2M1yQ9m SX31WuKf1dsXlsVDPdgMKRf3RI8+KadD3sw5pTHuE/wu9U7soz2J7N3N9Gh8kBjGs40f YLhLrMrCikD7GRY/dUUCQ0+fTrAH2itLKo5sHnmF0rTk5Oy6h/jdACxJC3Db3pLkPsZs 97c9oVuv2MIvms5qKQ+NwYZhbwyK9xvcKku0xpUOH5+urJoDjNyYa4ajjffssGEYGRcy t15szaBQPNV8iWwzhKdDoo5GcHQBj9CMh2HxIF3h9vx8cMvD9KC4kHWJdFm3TClPUaiT j2rQ== X-Gm-Message-State: AOAM530/w6S7DIdMb8n+7za6OBcteWEw0ltQZQ+pndhYLUBqA4ZQzVvR YZ6C8xmYP8OmI95j6w7YmgqlqRlUnJQ2kA== X-Google-Smtp-Source: ABdhPJzkOHuxJPX9u8w6hzM1eTHou32whD5fTEDPdbRDsHCAUdvnl3kj6FbvUtuDUvEvuW3HZpIemQ== X-Received: by 2002:a63:e747:: with SMTP id j7mr18301486pgk.235.1614697013985; Tue, 02 Mar 2021 06:56:53 -0800 (PST) Received: from shinobu ([156.146.35.76]) by smtp.gmail.com with ESMTPSA id s138sm22917284pfc.135.2021.03.02.06.56.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Mar 2021 06:56:53 -0800 (PST) Date: Tue, 2 Mar 2021 23:56:46 +0900 From: William Breathitt Gray To: Fabrice Gasnier Cc: jic23@kernel.org, david@lechnology.com, alexandre.torgue@foss.st.com, mcoquelin.stm32@gmail.com, olivier.moysan@foss.st.com, linux-iio@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] counter: stm32-timer-cnt: fix ceiling write max value Message-ID: References: <1614696235-24088-1-git-send-email-fabrice.gasnier@foss.st.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="wvX72FUvr+D6FcPx" Content-Disposition: inline In-Reply-To: <1614696235-24088-1-git-send-email-fabrice.gasnier@foss.st.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --wvX72FUvr+D6FcPx Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Mar 02, 2021 at 03:43:55PM +0100, Fabrice Gasnier wrote: > The ceiling value isn't checked before writing it into registers. The user > could write a value higher than the counter resolution (e.g. 16 or 32 bits > indicated by max_arr). This makes most significant bits to be truncated. > Fix it by checking the max_arr to report a range error [1] to the user. >=20 > Fixes: ad29937e206f ("counter: Add STM32 Timer quadrature encoder") >=20 > [1] https://lkml.org/lkml/2021/2/12/358 >=20 > Signed-off-by: Fabrice Gasnier Acked-by: William Breathitt Gray Side question: if priv->ceiling is tracking the current ceiling configuration, would it make sense to change stm32_count_ceiling_read() to print the value of priv->ceiling instead of doing a regmap_read() call? > --- > drivers/counter/stm32-timer-cnt.c | 5 +++++ > 1 file changed, 5 insertions(+) >=20 > diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-ti= mer-cnt.c > index ef2a974..2cf0c05 100644 > --- a/drivers/counter/stm32-timer-cnt.c > +++ b/drivers/counter/stm32-timer-cnt.c > @@ -32,6 +32,7 @@ struct stm32_timer_cnt { > struct regmap *regmap; > struct clk *clk; > u32 ceiling; > + u32 max_arr; > bool enabled; > struct stm32_timer_regs bak; > }; > @@ -185,6 +186,9 @@ static ssize_t stm32_count_ceiling_write(struct count= er_device *counter, > if (ret) > return ret; > =20 > + if (ceiling > priv->max_arr) > + return -ERANGE; > + > /* TIMx_ARR register shouldn't be buffered (ARPE=3D0) */ > regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, 0); > regmap_write(priv->regmap, TIM_ARR, ceiling); > @@ -360,6 +364,7 @@ static int stm32_timer_cnt_probe(struct platform_devi= ce *pdev) > priv->regmap =3D ddata->regmap; > priv->clk =3D ddata->clk; > priv->ceiling =3D ddata->max_arr; > + priv->max_arr =3D ddata->max_arr; > =20 > priv->counter.name =3D dev_name(dev); > priv->counter.parent =3D dev; > --=20 > 2.7.4 >=20 --wvX72FUvr+D6FcPx Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEk5I4PDJ2w1cDf/bghvpINdm7VJIFAmA+UggACgkQhvpINdm7 VJJt3g/+OVZcvByeL/DXkUu5tzYQxQ5xzzfViSO16w54567c2tGJuB8gBEFaK9eG Q5EzOeM9YaL982A/9OtqQup3CAJVkLizpy65aH1jDlPasA8JKKoelTfd+mAo58Vu hiwG3DXxwOCZNB7b2/+RaKcYyayviVsKgrl8mHUQ1SY81kM3/cdzSLSnAoxkfD8o 7w1CdXnOxDvvTD6rwcbc4izhSSxgHzvaGHFpKwwYa3gDpmCY44rDKsgXc0CL6F2B 1JRDgvIePdqIStdC8VXcGkUwmlrEVwfSqFgbAtadWuwMSR293AR1PCayvsA4yWyo 49fMudR81RlG5aFyYoOWbAvoKpiq81LlGQspGWFcND4mdbDR7qvEeuZO//0wbTxk 5bNTj/VrQeSyNb7HmDFzOaKwF3waAnYpwZyOcUKVwzVNyAJkRq4nCPn29OKHE3mC /Pbun8nAcbF0BP5R6QzX++aELtXzuArqJHOCDudTDQas0i7BNH0/+1KNKvisLTbk 6ftDbo0p3M90RUks08LLVpDzrAUGpyWeq7+VmWj1jHj22759PtbkEd/dxXKMkcQk OwD4+2zRN4yq4J2U8oiofAprHHgidhAXPB+Qvy4GXP1SewZl3q+cXCNn20Se39Xw uEDiJrNEX2zfbyRHx1V1zjqBlXFvCKIt62uqb8FBMmexuC5fmbc= =M2Bd -----END PGP SIGNATURE----- --wvX72FUvr+D6FcPx--