From: Arnd Bergmann <arnd@kernel.org>
To: Michael Schmitz <schmitzmic@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
Niklas Schnelle <schnelle@linux.ibm.com>,
Bjorn Helgaas <bhelgaas@google.com>,
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Greg Ungerer <gerg@linux-m68k.org>
Subject: Re: [RFC 02/32] Kconfig: introduce HAS_IOPORT option and select it as necessary
Date: Tue, 28 Dec 2021 22:41:18 -0500 [thread overview]
Message-ID: <CAK8P3a2j-OFUUp+haHoV4PyL-On4EASZ9+59SDqNqmL8Gv_k7Q@mail.gmail.com> (raw)
In-Reply-To: <d406b93a-0f76-d056-3380-65d459d05ea9@gmail.com>
On Tue, Dec 28, 2021 at 8:20 PM Michael Schmitz <schmitzmic@gmail.com> wrote:
> Am 28.12.2021 um 23:08 schrieb Geert Uytterhoeven:
> > On Mon, Dec 27, 2021 at 5:44 PM Niklas Schnelle <schnelle@linux.ibm.com> wrote:
> >> We introduce a new HAS_IOPORT Kconfig option to gate support for
> >> I/O port access. In a future patch HAS_IOPORT=n will disable compilation
> >> of the I/O accessor functions inb()/outb() and friends on architectures
> >> which can not meaningfully support legacy I/O spaces. On these platforms
> >> inb()/outb() etc are currently just stubs in asm-generic/io.h which when
> >> called will cause a NULL pointer access which some compilers actually
> >> detect and warn about.
> >>
> >> The dependencies on HAS_IOPORT in drivers as well as ifdefs for
> >> HAS_IOPORT specific sections will be added in subsequent patches on
> >> a per subsystem basis. Then a final patch will ifdef the I/O access
> >> functions on HAS_IOPORT thus turning any use not gated by HAS_IOPORT
> >> into a compile-time warning.
> >>
> >> Link: https://lore.kernel.org/lkml/CAHk-=wg80je=K7madF4e7WrRNp37e3qh6y10Svhdc7O8SZ_-8g@mail.gmail.com/
> >> Co-developed-by: Arnd Bergmann <arnd@kernel.org>
> >> Signed-off-by: Arnd Bergmann <arnd@kernel.org>
> >> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
> >
> > Thanks for your patch!
> >
> >> --- a/arch/m68k/Kconfig
> >> +++ b/arch/m68k/Kconfig
> >> @@ -16,6 +16,7 @@ config M68K
> >> select GENERIC_CPU_DEVICES
> >> select GENERIC_IOMAP
> >> select GENERIC_IRQ_SHOW
> >> + select HAS_IOPORT
> >> select HAVE_AOUT if MMU
> >> select HAVE_ASM_MODVERSIONS
> >> select HAVE_DEBUG_BUGVERBOSE
> >
> > This looks way too broad to me: most m68k platform do not have I/O
> > port access support.
> >
> > My gut feeling says:
> >
> > select HAS_IOPORT if PCI || ISA
> >
> > but that might miss some intricate details...
>
> In particular, this misses the Atari ROM port ISA adapter case -
>
> select HAS_IOPORT if PCI || ISA || ATARI_ROM_ISA
>
> might do instead.
Right, makes sense. I had suggested to go the easy way and assume that
each architecture would select HAS_IOPORT if any configuration supports
it, but it looks like for m68k there is a clearly defined set of platforms that
do.
Note that for the platforms that don't set any of the three symbols, the
fallback makes inb() an alias for readb() with a different argument type,
so there may be m68k specific drivers that rely on this, but those would
already be broken if ATARI_ROM_ISA is set.
Arnd
next prev parent reply other threads:[~2021-12-29 3:41 UTC|newest]
Thread overview: 108+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-27 16:42 [RFC 00/32] Kconfig: Introduce HAS_IOPORT and LEGACY_PCI options Niklas Schnelle
2021-12-27 16:42 ` [RFC 01/32] Kconfig: introduce and depend on LEGACY_PCI Niklas Schnelle
2021-12-27 17:48 ` Guenter Roeck
2021-12-28 2:09 ` Mauro Carvalho Chehab
2021-12-28 8:21 ` Greg Kroah-Hartman
2021-12-28 9:15 ` Mauro Carvalho Chehab
2021-12-28 10:58 ` Niklas Schnelle
2021-12-28 12:01 ` Greg Kroah-Hartman
2021-12-28 12:54 ` Mauro Carvalho Chehab
2021-12-28 15:06 ` Niklas Schnelle
2021-12-28 17:12 ` Mauro Carvalho Chehab
2021-12-29 11:45 ` Niklas Schnelle
2021-12-29 12:12 ` Mauro Carvalho Chehab
2021-12-29 16:03 ` Bjorn Helgaas
2021-12-29 16:55 ` Niklas Schnelle
2022-01-05 17:42 ` John Garry
2022-01-05 19:47 ` Bjorn Helgaas
2022-01-06 17:41 ` John Garry
2022-01-06 18:14 ` Bjorn Helgaas
2022-01-07 17:16 ` John Garry
2022-01-10 9:34 ` Niklas Schnelle
2021-12-27 16:42 ` [RFC 02/32] Kconfig: introduce HAS_IOPORT option and select it as necessary Niklas Schnelle
2021-12-28 10:08 ` Geert Uytterhoeven
2021-12-29 1:20 ` Michael Schmitz
2021-12-29 3:41 ` Arnd Bergmann [this message]
2021-12-29 4:15 ` Michael Schmitz
2021-12-30 1:48 ` Arnd Bergmann
2021-12-30 3:44 ` Michael Schmitz
2021-12-31 11:28 ` Niklas Schnelle
2021-12-31 16:04 ` Arnd Bergmann
2021-12-31 21:55 ` Michael Schmitz
2021-12-28 16:32 ` Mauro Carvalho Chehab
2021-12-27 16:42 ` [RFC 03/32] ACPI: Kconfig: add HAS_IOPORT dependencies Niklas Schnelle
2021-12-27 16:47 ` Rafael J. Wysocki
2021-12-27 17:02 ` Niklas Schnelle
2021-12-27 17:12 ` Rafael J. Wysocki
2021-12-27 17:15 ` Rafael J. Wysocki
2021-12-27 17:43 ` Niklas Schnelle
2021-12-28 15:20 ` Rafael J. Wysocki
2021-12-28 16:31 ` Niklas Schnelle
2021-12-27 16:42 ` [RFC 04/32] parport: PC style parport depends on HAS_IOPORT Niklas Schnelle
2021-12-28 10:14 ` Geert Uytterhoeven
2021-12-28 14:21 ` Niklas Schnelle
2021-12-29 2:58 ` Arnd Bergmann
2021-12-27 16:42 ` [RFC 05/32] char: impi, tpm: depend " Niklas Schnelle
2021-12-28 10:17 ` Geert Uytterhoeven
2021-12-28 12:13 ` Niklas Schnelle
2021-12-27 16:42 ` [RFC 06/32] speakup: Kconfig: add HAS_IOPORT dependencies Niklas Schnelle
2021-12-27 17:52 ` Samuel Thibault
2021-12-27 16:42 ` [RFC 07/32] Input: gameport: add ISA and " Niklas Schnelle
2021-12-27 16:42 ` [RFC 08/32] comedi: Kconfig: add " Niklas Schnelle
2021-12-27 16:42 ` [RFC 09/32] sound: " Niklas Schnelle
2021-12-27 16:42 ` [RFC 10/32] i2c: " Niklas Schnelle
2021-12-28 10:21 ` Geert Uytterhoeven
2021-12-28 12:13 ` Niklas Schnelle
2021-12-27 16:42 ` [RFC 11/32] Input: " Niklas Schnelle
2021-12-28 10:23 ` Geert Uytterhoeven
2021-12-27 16:42 ` [RFC 12/32] iio: adc: " Niklas Schnelle
2021-12-28 10:32 ` Geert Uytterhoeven
2021-12-28 12:50 ` Niklas Schnelle
2021-12-28 17:01 ` Jonathan Cameron
2022-01-30 15:05 ` Jonathan Cameron
2021-12-27 16:42 ` [RFC 13/32] hwmon: " Niklas Schnelle
2021-12-27 18:07 ` Guenter Roeck
2021-12-27 16:42 ` [RFC 14/32] leds: " Niklas Schnelle
2021-12-27 16:43 ` [RFC 15/32] media: " Niklas Schnelle
2021-12-27 16:43 ` [RFC 16/32] misc: handle " Niklas Schnelle
2021-12-28 8:15 ` Greg Kroah-Hartman
2021-12-27 16:43 ` [RFC 17/32] net: Kconfig: add " Niklas Schnelle
2021-12-27 17:28 ` Marc Kleine-Budde
2021-12-27 16:43 ` [RFC 18/32] pcmcia: " Niklas Schnelle
2021-12-27 18:41 ` Dominik Brodowski
2021-12-27 16:43 ` [RFC 19/32] platform: " Niklas Schnelle
2021-12-27 16:43 ` [RFC 20/32] pnp: " Niklas Schnelle
2021-12-27 16:43 ` [RFC 21/32] power: " Niklas Schnelle
2021-12-27 16:43 ` [RFC 22/32] video: handle " Niklas Schnelle
2021-12-27 16:43 ` [RFC 23/32] rtc: Kconfig: add " Niklas Schnelle
2021-12-27 16:43 ` [RFC 24/32] scsi: " Niklas Schnelle
2021-12-28 10:40 ` Geert Uytterhoeven
2021-12-27 16:43 ` [RFC 25/32] watchdog: " Niklas Schnelle
2021-12-27 18:03 ` Guenter Roeck
2021-12-28 9:58 ` Niklas Schnelle
2021-12-27 16:43 ` [RFC 26/32] drm: handle " Niklas Schnelle
2022-01-03 6:11 ` Gerd Hoffmann
2021-12-27 16:43 ` [RFC 27/32] PCI/sysfs: make I/O resource depend on HAS_IOPORT Niklas Schnelle
2021-12-27 22:04 ` Bjorn Helgaas
2021-12-27 16:43 ` [RFC 28/32] PCI: make quirk using inw() " Niklas Schnelle
2021-12-27 22:33 ` Bjorn Helgaas
2021-12-28 15:25 ` Niklas Schnelle
2021-12-28 16:35 ` Bjorn Helgaas
2021-12-28 16:52 ` Niklas Schnelle
2021-12-28 17:28 ` Bjorn Helgaas
2021-12-27 16:43 ` [RFC 29/32] firmware: dmi-sysfs: handle HAS_IOPORT dependencies Niklas Schnelle
2021-12-27 16:43 ` [RFC 30/32] /dev/port: don't compile file operations without CONFIG_DEVPORT Niklas Schnelle
2021-12-28 8:17 ` Greg Kroah-Hartman
2021-12-29 10:25 ` Niklas Schnelle
2021-12-29 10:38 ` Greg Kroah-Hartman
2021-12-30 16:19 ` Arnd Bergmann
2021-12-27 16:43 ` [RFC 31/32] usb: handle HAS_IOPORT dependencies Niklas Schnelle
2021-12-27 20:36 ` Alan Stern
2021-12-31 11:06 ` Niklas Schnelle
2021-12-31 17:15 ` Alan Stern
2022-01-03 11:35 ` Niklas Schnelle
2022-01-03 16:15 ` Alan Stern
2021-12-27 16:43 ` [RFC 32/32] asm-generic/io.h: drop inb() etc for HAS_IOPORT=n Niklas Schnelle
2022-01-06 17:45 ` [RFC 00/32] Kconfig: Introduce HAS_IOPORT and LEGACY_PCI options John Garry
2022-01-07 7:21 ` Niklas Schnelle
2022-01-07 16:57 ` John Garry
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