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Thu, 06 Aug 2020 05:44:59 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 4C13AC4339C; Thu, 6 Aug 2020 05:44:58 +0000 (UTC) Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: saiprakash.ranjan) by smtp.codeaurora.org (Postfix) with ESMTPSA id D85F6C433C9; Thu, 6 Aug 2020 05:44:56 +0000 (UTC) MIME-Version: 1.0 Date: Thu, 06 Aug 2020 11:14:56 +0530 From: Sai Prakash Ranjan To: Mike Leach Subject: Re: [PATCH v7 09/25] coresight: etm3x: allow etm3x to be built as a module In-Reply-To: References: <20200805025458.2978-1-tingwei@codeaurora.org> <20200805025458.2978-10-tingwei@codeaurora.org> <83abb52f-4c3b-9b50-4053-84343d75eeb3@arm.com> Message-ID: X-Sender: saiprakash.ranjan@codeaurora.org User-Agent: Roundcube Webmail/1.3.9 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200806_014517_931095_9A2CA957 X-CRM114-Status: GOOD ( 34.21 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: tsoni@codeaurora.org, Kim Phillips , Mathieu Poirier , Suzuki K Poulose , Alexander Shishkin , Greg Kroah-Hartman , Coresight ML , Randy Dunlap , Mian Yousaf Kaukab , Russell King , Mao Jinlong , Tingwei Zhang , Leo Yan , linux-arm-kernel Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Mike, On 2020-08-05 18:24, Mike Leach wrote: > Hi, > > On Wed, 5 Aug 2020 at 12:05, Suzuki K Poulose > wrote: >> >> On 08/05/2020 03:54 AM, Tingwei Zhang wrote: >> > From: Kim Phillips >> > >> > Allow to build coresight-etm3x as a module, for ease of development. >> > >> > - Kconfig becomes a tristate, to allow =m >> > - append -core to source file name to allow module to >> > be called coresight-etm3x by the Makefile >> > - add an etm_remove function, for module unload >> > - add a MODULE_DEVICE_TABLE for autoloading on boot >> > >> > Cc: Mathieu Poirier >> > Cc: Leo Yan >> > Cc: Alexander Shishkin >> > Cc: Randy Dunlap >> > Cc: Suzuki K Poulose >> > Cc: Greg Kroah-Hartman >> > Cc: Russell King >> > Signed-off-by: Kim Phillips >> > Signed-off-by: Tingwei Zhang >> > Reviewed-by: Mike Leach >> > --- >> > drivers/hwtracing/coresight/Kconfig | 5 +++- >> > drivers/hwtracing/coresight/Makefile | 3 ++- >> > ...resight-etm3x.c => coresight-etm3x-core.c} | 27 ++++++++++++++++++- >> > 3 files changed, 32 insertions(+), 3 deletions(-) >> > rename drivers/hwtracing/coresight/{coresight-etm3x.c => coresight-etm3x-core.c} (97%) >> > >> > diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig >> > index 6433f835fc97..8fd9fd139cf3 100644 >> > --- a/drivers/hwtracing/coresight/Kconfig >> > +++ b/drivers/hwtracing/coresight/Kconfig >> > @@ -65,7 +65,7 @@ config CORESIGHT_SINK_ETBV10 >> > special enhancement or added features. >> > >> > config CORESIGHT_SOURCE_ETM3X >> > - bool "CoreSight Embedded Trace Macrocell 3.x driver" >> > + tristate "CoreSight Embedded Trace Macrocell 3.x driver" >> > depends on !ARM64 >> > select CORESIGHT_LINKS_AND_SINKS >> > help >> > @@ -74,6 +74,9 @@ config CORESIGHT_SOURCE_ETM3X >> > This is primarily useful for instruction level tracing. Depending >> > the ETM version data tracing may also be available. >> > >> > + To compile this driver as a module, choose M here: the >> > + module will be called coresight-etm3x. >> > + >> > config CORESIGHT_SOURCE_ETM4X >> > bool "CoreSight Embedded Trace Macrocell 4.x driver" >> > depends on ARM64 >> > diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile >> > index 19497d1d92bf..d619cfd0abd8 100644 >> > --- a/drivers/hwtracing/coresight/Makefile >> > +++ b/drivers/hwtracing/coresight/Makefile >> > @@ -11,7 +11,8 @@ obj-$(CONFIG_CORESIGHT_SINK_TPIU) += coresight-tpiu.o >> > obj-$(CONFIG_CORESIGHT_SINK_ETBV10) += coresight-etb10.o >> > obj-$(CONFIG_CORESIGHT_LINKS_AND_SINKS) += coresight-funnel.o \ >> > coresight-replicator.o >> > -obj-$(CONFIG_CORESIGHT_SOURCE_ETM3X) += coresight-etm3x.o coresight-etm-cp14.o \ >> > +obj-$(CONFIG_CORESIGHT_SOURCE_ETM3X) += coresight-etm3x.o >> > +coresight-etm3x-y := coresight-etm3x-core.o coresight-etm-cp14.o \ >> > coresight-etm3x-sysfs.o >> > obj-$(CONFIG_CORESIGHT_SOURCE_ETM4X) += coresight-etm4x.o \ >> > coresight-etm4x-sysfs.o >> > diff --git a/drivers/hwtracing/coresight/coresight-etm3x.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c >> > similarity index 97% >> > rename from drivers/hwtracing/coresight/coresight-etm3x.c >> > rename to drivers/hwtracing/coresight/coresight-etm3x-core.c >> > index bf22dcfd3327..82b333c40006 100644 >> > --- a/drivers/hwtracing/coresight/coresight-etm3x.c >> > +++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c >> > @@ -895,6 +895,23 @@ static int etm_probe(struct amba_device *adev, const struct amba_id *id) >> > return ret; >> > } >> > >> > +static int __exit etm_remove(struct amba_device *adev) >> > +{ >> > + struct etm_drvdata *drvdata = dev_get_drvdata(&adev->dev); >> > + >> > + etm_perf_symlink(drvdata->csdev, false); >> > + >> > + if (--etm_count == 0) { >> >> Could there be multiple instances of remove running in parallel ? I >> believe we need some sort of a protection here to avoid racing. >> >> Or even better, I would recommend leaving the notifiers registered >> at module_init and removed at the cleanup of the module, just like >> we are doing for etm4x driver, and get rid of this silly scheme. > > I would agree that this needs addressing but this is an independent > problem that could be better served by a separate patchset, rather > than add feature creep to this set. The same schema is used in the CTI > driver as well and needs fixing there. > >> Like here : >> >> https://lkml.kernel.org/r/20200729051310.18436-1-saiprakash.ranjan@codeaurora.org >> > > This conflicts with the init / exit fns created for module loading in > the etm4x part of this set.. > > A decision needs to be made on which set gets applied first - my view > is that the module set could go first, then a set fixing the PM > registration issues for all three affected drivers to be applied next. The etm4_count race is a bug fix which in my opinion should go first because this feature would likely to be merged for 5.10 and till then we would have a bug lying around if the fix patch for the race does not go in right? Thanks, Sai -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel