Message-ID: <66cae9eb4fdd0b02a1fe228454f75aecb45802ed.camel@linux.ibm.com>
Subject: Re: [RFC 25/32] watchdog: Kconfig: add HAS_IOPORT dependencies
From:   Niklas Schnelle <schnelle@linux.ibm.com>
To:     Guenter Roeck <linux@roeck-us.net>,
        Arnd Bergmann <arnd@kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        John Garry <john.garry@huawei.com>,
        Nick Hu <nickhu@andestech.com>,
        Greentime Hu <green.hu@gmail.com>,
        Vincent Chen <deanbo422@gmail.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>, Guo Ren <guoren@kernel.org>,
        Wim Van Sebroeck <wim@linux-watchdog.org>
Cc:     linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
        linux-pci@vger.kernel.org, linux-riscv@lists.infradead.org,
        linux-csky@vger.kernel.org, linux-watchdog@vger.kernel.org
Date:   Tue, 28 Dec 2021 10:58:31 +0100
In-Reply-To: <280c0490-3a68-5498-5751-d53162203b5b@roeck-us.net>
References: <20211227164317.4146918-1-schnelle@linux.ibm.com>
         <20211227164317.4146918-26-schnelle@linux.ibm.com>
         <280c0490-3a68-5498-5751-d53162203b5b@roeck-us.net>
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On Mon, 2021-12-27 at 10:03 -0800, Guenter Roeck wrote:
> On 12/27/21 8:43 AM, Niklas Schnelle wrote:
> > In a future patch HAS_IOPORT=n will result in inb()/outb() and friends
> > not being declared. We thus need to add HAS_IOPORT as dependency for
> > those drivers using them.
> > 
> 
> How is the need for HAS_IOPORT determined, when exactly is it needed,
> and when not ?

I mostly used "make allyesconfig" on s390 with the accessors ifdeffed
out (i.e. patch 32) to find where the I/O port accesses were compiled
in. This means that it doesn't find drivers which pull in a HAS_IOPORT
dependency transitively e.g. by depending on x86 or ACPI. It should get
those that use e.g. "|| COMPILE_TEST" though. This might not be ideal
but on the other hand it should catch all those drivers that currently
built with known broken code.

> 
> $ git grep -E "inb|inw" drivers/watchdog/ | cut -f1 -d: | sort -u
> drivers/watchdog/acquirewdt.c
> drivers/watchdog/advantechwdt.c
> 
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