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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4D474C433F5 for ; Thu, 3 Feb 2022 12:08:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235416AbiBCMII (ORCPT ); Thu, 3 Feb 2022 07:08:08 -0500 Received: from foss.arm.com ([217.140.110.172]:42786 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229794AbiBCMIG (ORCPT ); Thu, 3 Feb 2022 07:08:06 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 80D7511D4; Thu, 3 Feb 2022 04:08:06 -0800 (PST) Received: from [10.57.13.234] (unknown [10.57.13.234]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5AE903F774; Thu, 3 Feb 2022 04:08:05 -0800 (PST) Message-ID: <83349132-eac4-d05d-ff47-204fa8914922@arm.com> Date: Thu, 3 Feb 2022 12:08:03 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH 01/15] coresight: Make ETM4x TRCIDR0 register accesses consistent with sysreg.h Content-Language: en-US To: Suzuki K Poulose , mathieu.poirier@linaro.org, coresight@lists.linaro.org Cc: leo.yan@linaro.com, mike.leach@linaro.org, Leo Yan , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20220202160226.37858-1-james.clark@arm.com> <20220202160226.37858-2-james.clark@arm.com> <41b08fa5-6333-48e8-4727-2082c001e148@arm.com> <3df77ddd-31df-c2d8-7aac-e21c7ba48f1e@arm.com> From: James Clark In-Reply-To: <3df77ddd-31df-c2d8-7aac-e21c7ba48f1e@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/02/2022 10:54, Suzuki K Poulose wrote: > On 03/02/2022 10:40, James Clark wrote: >> >> >> On 02/02/2022 17:05, Suzuki K Poulose wrote: >>> Hi James >>> >>> Thanks for taking this tedious task of cleaning the code and making >>> this robust and readable. >>> >>> One minor comment below. >>> >>> On 02/02/2022 16:02, James Clark wrote: >>>> This is a no-op change for style and consistency and has no effect on the >>>> binary produced by gcc-11. >>>> >>>> Signed-off-by: James Clark >>>> --- >>>>    .../coresight/coresight-etm4x-core.c          | 37 +++++-------------- >>>>    drivers/hwtracing/coresight/coresight-etm4x.h | 17 +++++++++ >>>>    drivers/hwtracing/coresight/coresight-priv.h  |  1 + >>>>    3 files changed, 27 insertions(+), 28 deletions(-) >>>> >>>> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c >>>> index bf18128cf5de..8aefee4e72fd 100644 >>>> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c >>>> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c >>>> @@ -1091,41 +1091,22 @@ static void etm4_init_arch_data(void *info) >>>>        etmidr0 = etm4x_relaxed_read32(csa, TRCIDR0); >>>>          /* INSTP0, bits[2:1] P0 tracing support field */ >>>> -    if (BMVAL(etmidr0, 1, 1) && BMVAL(etmidr0, 2, 2)) >>>> -        drvdata->instrp0 = true; >>>> -    else >>>> -        drvdata->instrp0 = false; >>>> - >>>> +    drvdata->instrp0 = !!((REG_VAL(etmidr0, TRCIDR0_INSTP0) & 0b01) && >>>> +                  (REG_VAL(etmidr0, TRCIDR0_INSTP0) & 0b10)); >>> >>> I don't understand this check. For ETMv4, here is what I find in the spec (ARM IHI 0064C) >>> >>> P0 tracing support field. The permitted values are: >>> 0b00  Tracing of load and store instructions as P0 elements is not >>>        supported. >>> 0b11  Tracing of load and store instructions as P0 elements is >>>        supported, so TRCCONFIGR.INSTP0 is supported. >>> >>> All other values are reserved. >>> >>> So the check could simply be : >>> >>>      drvdata->instrp0 = (REG_VAL(emtidr0, TRCIDR0_INSTP0) == 0b11; >> >> Yes I can make this change, but it does make the compiler emit a slightly different binary >> so we can't rely on that to check the refactor is ok. >> >> Should I change it in this commit or stick it on the very end? Probably the end is best >> in case I have to do any rebases and I still need to validate there are no mistakes. > > I would say, fix the existing check first and then convert to use the > updated symbols. > > That way we could queue the fix separately and you may be able to rebase > your next version on the updated tree ? Good idea, I've resubmitted v2 with that and the other comments you left. > > > Cheers > Suzuki