From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [PATCH] zcrypt: handle AP Info notification from CHSC SEI command References: <1548870526-30595-1-git-send-email-akrowiak@linux.ibm.com> <88b72363-9dca-4653-c326-9c37b6349a32@linux.ibm.com> <20190201090159.GC3770@osiris> From: Tony Krowiak Date: Tue, 5 Feb 2019 15:26:09 -0500 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Language: en-US Content-Transfer-Encoding: 8bit Message-Id: <70880c70-382b-2753-be46-4167a6e6b15f@linux.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: Harald Freudenberger , Heiko Carstens Cc: Sebastian Ott , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, Martin Schwidefsky , oberpar@linux.ibm.com, pmorel@linux.ibm.com, pasic@linux.ibm.com, cohuck@redhat.com List-ID: On 2/4/19 5:06 AM, Harald Freudenberger wrote: > On 01.02.19 16:38, Tony Krowiak wrote: >> On 2/1/19 4:01 AM, Heiko Carstens wrote: >>> On Thu, Jan 31, 2019 at 06:28:39PM -0500, Tony Krowiak wrote: >>>> On 1/30/19 1:32 PM, Sebastian Ott wrote: >>>>> On Wed, 30 Jan 2019, Tony Krowiak wrote: >>>>>> +#if IS_ENABLED(CONFIG_ZCRYPT) >>>>>> +void ap_bus_cfg_chg(void); >>>>>> +#else >>>>>> +#error "no CONFIG_ZCRYPT" >>>>>     ^ >>>>> I don't think that's the right thing to do here. >>>> >>>> I'd like to leave it. If somebody edits .config >>>> and sets CONFIG_ZCRYPT=n, then the build will >>>> fail. The preprocessor error above tells them >>>> why. >>> >>> No, the kernel build should never fail if a config option is not set. >>> Also the above should be "#ifdef CONFIG_ZCRYPT". >> >> Will do. >> >>> >>> In addition (this isn't quoted unfortunately) the alternative function >>> in the header file is missing the "inline" attribute. Can you please >>> add that too? >> >> I can. >> >>> >>> static inline void ap_bus_cfg_chg(void) { } >>> >>>>>> +* A config change has happened, Force an ap bus rescan. >>>>>> +*/ >>>>>> +void ap_bus_cfg_chg(void) >>>>>> +{ >>>>>> +    AP_DBF(DBF_INFO, "%s config change, forcing bus rescan\n", __func__); >>>>>> + >>>>>> +    ap_bus_force_rescan(); >>>>>> +} >>>>>> +EXPORT_SYMBOL(ap_bus_cfg_chg); >>>>> >>>>> There is no need for the export symbol - you don't call that function >>>> >from module code. >>>>> As an unrelated question, just to be sure: ap_bus.c is compiled as >>>>> built-in even with ZCRYPT=m, right? >>>> >>>> No. If you edit .config and set CONFIG_ZCRYPT=m, ap_bus.c will be built >>>> into the zcrypt.ko module. Through some other magic, the zcrypt module >>>> is loaded when linux boots. >>> >>> If that happens, then we have a build problem that needs to be >>> fixed. What exactly are you doing to get the ap code linked into the >>> zcrypt module? >> >> To tell you the truth, I don't know. The build configuration precedes my >> creating this patch by many years. I only discovered these anomalies by >> playing with the CONFIG_ZCRYPT option in response to Sebastian's >> comments. I will have to take this up with our internal IBM maintainer. >> >>> >> > As Martin already pointed out the ap bus code is statically build into the kernel > with this line in the Makefile: >   obj-$(subst m,y,$(CONFIG_ZCRYPT)) += ap.o > So CONFIG_ZCRYPT may have the value 'm' or 'y' > and this is also the reason why a simple #ifdef CONFIG_ZCRYPT does not > work, instead #if IS_ENABLED(CONFIG_ZCRYPT) has to be used. > > Only the ap stuff (which is: ap_bus.o, ap_card.o and ap_queue.o) is statically > build into the kernel. The zcrypt kernel module is loaded as a dependency > when a crypto card is detected. So detecting a CEX4 forces kernel module > zcrypt_cex4.ko which forces the zcrypt.ko to insert into the kernel. > So all global functions in ap_bus.c are available when CONFIG_ZCRYPT is > enabled. However, I thought the symbol still needs an EXPORT_SYMBOL() > statement. Otherwise I should throw out all these statements. > > Harald Thank you for explaining that Harald. Tony K >