From: "Maciej W. Rozycki" <macro@orcam.me.uk>
To: Arnd Bergmann <arnd@kernel.org>
Cc: Bjorn Helgaas <helgaas@kernel.org>,
Niklas Schnelle <schnelle@linux.ibm.com>,
Arnd Bergmann <arnd@arndb.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-arch <linux-arch@vger.kernel.org>,
linux-pci <linux-pci@vger.kernel.org>,
Richard Henderson <rth@twiddle.net>,
Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
Matt Turner <mattst88@gmail.com>,
Russell King <linux@armlinux.org.uk>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Michal Simek <monstr@monstr.eu>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
"James E.J. Bottomley" <James.Bottomley@hansenpartnership.com>,
Helge Deller <deller@gmx.de>,
Michael Ellerman <mpe@ellerman.id.au>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Yoshinori Sato <ysato@users.sourceforge.jp>,
Rich Felker <dalias@libc.org>,
"David S. Miller" <davem@davemloft.net>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
<x86@kernel.org>,
"open list:ALPHA PORT" <linux-alpha@vger.kernel.org>,
"moderated list:ARM PORT" <linux-arm-kernel@lists.infradead.org>,
"open list:IA64 (Itanium) PLATFORM" <linux-ia64@vger.kernel.org>,
"open list:M68K ARCHITECTURE" <linux-m68k@lists.linux-m68k.org>,
"open list:MIPS" <linux-mips@vger.kernel.org>,
"open list:PARISC ARCHITECTURE" <linux-parisc@vger.kernel.org>,
"open list:LINUX FOR POWERPC (32-BIT AND 64-BIT)"
<linuxppc-dev@lists.ozlabs.org>,
"open list:RISC-V ARCHITECTURE" <linux-riscv@lists.infradead.org>,
"open list:SUPERH" <linux-sh@vger.kernel.org>,
"open list:SPARC + UltraSPARC (sparc/sparc64)"
<sparclinux@vger.kernel.org>
Subject: Re: [RFC v2 01/39] Kconfig: introduce HAS_IOPORT option and select it as necessary
Date: Fri, 6 May 2022 13:27:20 +0100 (BST) [thread overview]
Message-ID: <alpine.DEB.2.21.2205061314110.52331@angie.orcam.me.uk> (raw)
In-Reply-To: <CAK8P3a0NzG=3tDLCdPj2=A__2r_+xiiUTW=WJCBNp29x_A63Og@mail.gmail.com>
On Fri, 6 May 2022, Arnd Bergmann wrote:
> > If this is PCI/PCIe indeed, then an I/O access is just a different bit
> > pattern put on the bus/in the TLP in the address phase. So what is there
> > inherent to the s390 architecture that prevents that different bit pattern
> > from being used?
>
> The hardware design for PCI on s390 is very different from any other
> architecture, and more abstract. Rather than implementing MMIO register
> access as pointer dereference, this is a separate CPU instruction that
> takes a device/bar plus offset as arguments rather than a pointer, and
> Linux encodes this back into a fake __iomem token.
OK, that seems to me like a reasonable and quite a clean design (on the
hardware side).
So what happens if the instruction is given an I/O rather than memory BAR
as the relevant argument? Is the address space indicator bit (bit #0)
simply ignored or what?
> > But that has nothing to do with the presence or absence of any specific
> > processor instructions. It's just a limitation of bus glue. So I guess
> > it's just that all PCI/PCIe glue logic implementations for s390 have such
> > a limitation, right?
>
> There are separate instructions for PCI memory and config space, but
> no instructions for I/O space, or for non-PCI MMIO that it could be mapped
> into.
The PCI configuration space was retrofitted into x86 systems (and is
accessed in an awkward manner with them), but with a new design such a
clean approach is most welcome IMHO. Thank you for your explanation.
Maciej
next prev parent reply other threads:[~2022-05-06 12:28 UTC|newest]
Thread overview: 196+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-29 13:49 [RFC v2 00/39] Kconfig: Introduce HAS_IOPORT config option Niklas Schnelle
2022-04-29 13:49 ` [RFC v2 01/39] Kconfig: introduce HAS_IOPORT option and select it as necessary Niklas Schnelle
2022-05-01 22:40 ` Maciej W. Rozycki
2022-05-04 21:08 ` Bjorn Helgaas
2022-05-04 21:31 ` Arnd Bergmann
2022-05-05 8:10 ` Niklas Schnelle
2022-05-05 16:10 ` Bjorn Helgaas
2022-05-05 17:39 ` Arnd Bergmann
2022-05-05 19:53 ` Bjorn Helgaas
2022-05-06 9:12 ` Finn Thain
2022-05-06 11:18 ` Niklas Schnelle
2022-05-07 0:01 ` Finn Thain
2022-05-07 13:14 ` Arnd Bergmann
2022-05-07 23:59 ` Finn Thain
2022-05-08 0:15 ` Finn Thain
2022-05-06 9:38 ` Niklas Schnelle
2022-05-06 11:07 ` John Garry
2022-05-06 10:20 ` Maciej W. Rozycki
2022-05-06 11:33 ` Arnd Bergmann
2022-05-06 12:27 ` Maciej W. Rozycki [this message]
2022-05-06 12:53 ` David Laight
2022-05-06 13:08 ` Geert Uytterhoeven
2022-05-06 13:40 ` Maciej W. Rozycki
2022-05-06 14:03 ` David Laight
2022-05-06 15:02 ` Geert Uytterhoeven
2022-05-06 13:15 ` Maciej W. Rozycki
2022-05-06 13:28 ` David Laight
2022-05-06 14:44 ` Maciej W. Rozycki
2022-05-06 14:56 ` Geert Uytterhoeven
2022-05-06 15:03 ` Maciej W. Rozycki
2022-05-06 12:53 ` Arnd Bergmann
2022-05-06 13:15 ` Niklas Schnelle
2022-05-06 13:16 ` Maciej W. Rozycki
2022-05-06 12:55 ` Niklas Schnelle
2022-05-06 12:42 ` Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 02/39] ACPI: add dependency on HAS_IOPORT Niklas Schnelle
2022-05-04 13:23 ` Rafael J. Wysocki
2022-05-04 17:53 ` Bjorn Helgaas
2022-05-04 19:58 ` Arnd Bergmann
2022-05-05 8:20 ` Niklas Schnelle
2022-05-05 19:36 ` Bjorn Helgaas
2022-04-29 13:50 ` [PATCH 02/37] ata: add HAS_IOPORT dependencies Niklas Schnelle
2022-04-29 14:27 ` Niklas Schnelle
2022-04-29 13:50 ` [PATCH 03/37] ACPI: add dependency on HAS_IOPORT Niklas Schnelle
2022-04-29 14:28 ` Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 03/39] ata: add HAS_IOPORT dependencies Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 04/39] char: impi, tpm: depend on HAS_IOPORT Niklas Schnelle
2022-04-29 14:23 ` Niklas Schnelle
2022-04-29 14:33 ` Ahmad Fatoum
2022-05-02 14:34 ` Niklas Schnelle
2022-04-29 13:50 ` [PATCH 04/37] parport: PC style parport depends " Niklas Schnelle
2022-04-29 14:28 ` Niklas Schnelle
2022-04-29 13:50 ` [PATCH 05/37] char: impi, tpm: depend " Niklas Schnelle
2022-04-29 14:02 ` Ahmad Fatoum
2022-04-29 13:50 ` [RFC v2 05/39] comedi: add HAS_IOPORT dependencies Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 06/39] counter: " Niklas Schnelle
2022-04-29 13:50 ` [PATCH 06/37] speakup: add HAS_IOPORT dependency for SPEAKUP_SERIALIO Niklas Schnelle
2022-04-29 14:28 ` Samuel Thibault
2022-04-29 14:28 ` Niklas Schnelle
2022-04-29 14:29 ` Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 07/39] /dev/port: don't compile file operations without CONFIG_DEVPORT Niklas Schnelle
2022-04-29 13:50 ` [PATCH 07/37] Input: gameport: add ISA and HAS_IOPORT dependencies Niklas Schnelle
2022-04-29 14:29 ` Niklas Schnelle
2022-04-29 13:50 ` [PATCH 08/37] comedi: add " Niklas Schnelle
2022-04-29 14:30 ` Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 08/39] drm: handle " Niklas Schnelle
2022-04-29 13:50 ` [PATCH 09/37] counter: add " Niklas Schnelle
2022-04-29 14:30 ` Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 09/39] firmware: dmi-sysfs: handle HAS_IOPORT=n Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 10/39] gpio: add HAS_IOPORT dependencies Niklas Schnelle
2022-04-29 14:32 ` William Breathitt Gray
2022-04-29 14:46 ` Niklas Schnelle
2022-04-29 15:37 ` William Breathitt Gray
2022-05-01 21:55 ` Linus Walleij
2022-05-02 12:53 ` Niklas Schnelle
2022-05-03 13:08 ` David Laight
2022-05-03 14:03 ` William Breathitt Gray
2022-05-04 11:46 ` Maciej W. Rozycki
2022-05-04 12:45 ` David Laight
2022-05-04 13:02 ` Maciej W. Rozycki
2022-05-02 13:21 ` Maciej W. Rozycki
2022-04-29 13:50 ` [RFC v2 11/39] hwmon: " Niklas Schnelle
2022-04-30 0:37 ` Guenter Roeck
2022-04-29 13:50 ` [PATCH 11/37] sound: " Niklas Schnelle
2022-04-29 14:30 ` Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 12/39] i2c: " Niklas Schnelle
2022-05-14 14:06 ` Wolfram Sang
2022-04-29 13:50 ` [RFC v2 13/39] iio: adc: Kconfig: " Niklas Schnelle
2022-05-01 16:51 ` Jonathan Cameron
2022-04-29 13:50 ` [PATCH 13/37] Input: " Niklas Schnelle
2022-04-29 14:31 ` Niklas Schnelle
2022-04-29 13:50 ` [PATCH 14/37] iio: adc: Kconfig: " Niklas Schnelle
2022-04-29 14:31 ` Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 14/39] Input: " Niklas Schnelle
2022-04-29 13:50 ` [PATCH 15/37] hwmon: " Niklas Schnelle
2022-04-29 14:31 ` Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 15/39] Input: gameport: add ISA and " Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 16/39] leds: add " Niklas Schnelle
2022-04-29 18:54 ` Pavel Machek
2022-05-02 8:31 ` Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 17/39] media: " Niklas Schnelle
2022-04-29 15:36 ` Sean Young
2022-04-29 13:50 ` [RFC v2 18/39] misc: " Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 19/39] mISDN: " Niklas Schnelle
2022-04-29 13:50 ` [PATCH 19/37] mpt fusion: " Niklas Schnelle
2022-04-29 14:32 ` Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 20/39] " Niklas Schnelle
2022-04-29 13:50 ` [PATCH 20/37] net: " Niklas Schnelle
2022-04-29 14:33 ` Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 21/39] " Niklas Schnelle
2022-04-29 14:13 ` Marc Kleine-Budde
2022-05-01 22:48 ` Maciej W. Rozycki
2022-05-03 12:45 ` Niklas Schnelle
2022-05-03 13:36 ` Maciej W. Rozycki
2022-04-29 13:50 ` [PATCH 21/37] pcmcia: " Niklas Schnelle
2022-04-29 14:33 ` Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 22/39] parport: PC style parport depends on HAS_IOPORT Niklas Schnelle
2022-04-29 13:50 ` [PATCH 22/37] platform: add HAS_IOPORT dependencies Niklas Schnelle
2022-04-29 14:33 ` Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 23/39] PCI: make quirk using inw() depend on HAS_IOPORT Niklas Schnelle
2022-06-08 18:30 ` Bjorn Helgaas
2022-04-29 13:50 ` [PATCH 23/37] pnp: add HAS_IOPORT dependencies Niklas Schnelle
2022-04-29 14:34 ` Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 24/39] PCI/sysfs: make I/O resource depend on HAS_IOPORT Niklas Schnelle
2022-06-08 18:32 ` Bjorn Helgaas
2022-04-29 13:50 ` [PATCH 24/37] power: add HAS_IOPORT dependencies Niklas Schnelle
2022-04-29 14:34 ` Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 25/39] pcmcia: " Niklas Schnelle
2022-05-03 23:38 ` Bjorn Helgaas
2022-05-04 10:33 ` Arnd Bergmann
2022-05-04 12:38 ` Maciej W. Rozycki
2022-05-04 14:07 ` Arnd Bergmann
2022-05-04 14:24 ` Maciej W. Rozycki
2022-05-04 17:22 ` Bjorn Helgaas
2022-05-05 8:45 ` Maciej W. Rozycki
2022-05-05 19:38 ` Bjorn Helgaas
2022-05-04 14:44 ` David Laight
2022-05-05 12:03 ` Maciej W. Rozycki
2022-05-04 14:59 ` Niklas Schnelle
2022-04-29 13:50 ` [PATCH 25/37] video: handle " Niklas Schnelle
2022-04-29 14:35 ` Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 26/39] platform: add " Niklas Schnelle
2022-04-29 13:50 ` [PATCH 26/37] rtc: " Niklas Schnelle
2022-04-29 14:46 ` Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 27/39] pnp: " Niklas Schnelle
2022-04-29 13:50 ` [PATCH 27/37] scsi: " Niklas Schnelle
2022-04-29 14:46 ` Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 28/39] power: " Niklas Schnelle
2022-04-29 13:50 ` [PATCH 28/37] staging: sm750fb: " Niklas Schnelle
2022-04-29 14:47 ` Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 29/39] rtc: " Niklas Schnelle
2022-05-17 22:15 ` Alexandre Belloni
2022-05-18 13:47 ` Niklas Schnelle
2022-06-01 12:25 ` Maciej W. Rozycki
2022-04-29 13:50 ` [PATCH 29/37] tty: serial: " Niklas Schnelle
2022-04-29 14:47 ` Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 30/39] scsi: " Niklas Schnelle
2022-05-04 20:42 ` Bjorn Helgaas
2022-05-04 21:34 ` Arnd Bergmann
2022-05-05 16:06 ` Bjorn Helgaas
2022-04-29 13:50 ` [PATCH 30/37] watchdog: " Niklas Schnelle
2022-04-29 14:47 ` Niklas Schnelle
2022-04-29 13:50 ` [PATCH 31/37] drm: handle " Niklas Schnelle
2022-04-29 14:47 ` Niklas Schnelle
2022-04-29 13:50 ` [RFC v2 31/39] sound: add " Niklas Schnelle
2022-05-09 8:53 ` Takashi Iwai
2022-05-09 9:20 ` Arnd Bergmann
2022-05-09 10:07 ` Takashi Iwai
2022-05-09 12:14 ` Niklas Schnelle
2022-04-29 13:50 ` [PATCH 32/37] PCI/sysfs: make I/O resource depend on HAS_IOPORT Niklas Schnelle
2022-04-29 14:48 ` Niklas Schnelle
2022-05-05 21:41 ` Bjorn Helgaas
2022-04-29 13:50 ` [RFC v2 32/39] speakup: add HAS_IOPORT dependency for SPEAKUP_SERIALIO Niklas Schnelle
2022-04-29 13:50 ` [PATCH 33/37] PCI: make quirk using inw() depend on HAS_IOPORT Niklas Schnelle
2022-04-29 14:48 ` Niklas Schnelle
2022-05-05 21:44 ` Bjorn Helgaas
2022-04-29 13:50 ` [RFC v2 33/39] staging: add HAS_IOPORT dependencies Niklas Schnelle
2022-04-29 13:50 ` [PATCH 34/37] firmware: dmi-sysfs: handle HAS_IOPORT=n Niklas Schnelle
2022-04-29 14:48 ` Niklas Schnelle
2022-04-29 13:51 ` [RFC v2 34/39] tty: serial: add HAS_IOPORT dependencies Niklas Schnelle
2022-05-02 9:15 ` Maciej W. Rozycki
2022-04-29 13:51 ` [PATCH 35/37] /dev/port: don't compile file operations without CONFIG_DEVPORT Niklas Schnelle
2022-04-29 14:49 ` Niklas Schnelle
2022-04-29 13:51 ` [RFC v2 35/39] usb: handle HAS_IOPORT dependencies Niklas Schnelle
2022-04-30 12:56 ` Alan Stern
2022-05-02 8:26 ` Niklas Schnelle
2022-04-29 13:51 ` [PATCH 36/37] " Niklas Schnelle
2022-04-29 14:49 ` Niklas Schnelle
2022-04-29 13:51 ` [RFC v2 36/39] video: " Niklas Schnelle
2022-04-29 13:51 ` [PATCH 37/37] asm-generic/io.h: drop inb() etc for HAS_IOPORT=n Niklas Schnelle
2022-04-29 14:49 ` Niklas Schnelle
2022-04-29 13:51 ` [RFC v2 37/39] watchdog: add HAS_IOPORT dependencies Niklas Schnelle
2022-04-30 0:38 ` Guenter Roeck
2022-04-29 13:51 ` [RFC v2 38/39] wireless: " Niklas Schnelle
2022-04-29 14:40 ` Kalle Valo
2022-04-29 13:51 ` [RFC v2 39/39] asm-generic/io.h: drop inb() etc for HAS_IOPORT=n Niklas Schnelle
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=alpine.DEB.2.21.2205061314110.52331@angie.orcam.me.uk \
--to=macro@orcam.me.uk \
--cc=James.Bottomley@hansenpartnership.com \
--cc=aou@eecs.berkeley.edu \
--cc=arnd@arndb.de \
--cc=arnd@kernel.org \
--cc=bp@alien8.de \
--cc=catalin.marinas@arm.com \
--cc=dalias@libc.org \
--cc=dave.hansen@linux.intel.com \
--cc=davem@davemloft.net \
--cc=deller@gmx.de \
--cc=geert@linux-m68k.org \
--cc=gregkh@linuxfoundation.org \
--cc=helgaas@kernel.org \
--cc=ink@jurassic.park.msu.ru \
--cc=linux-alpha@vger.kernel.org \
--cc=linux-arch@vger.kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-ia64@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-m68k@lists.linux-m68k.org \
--cc=linux-mips@vger.kernel.org \
--cc=linux-parisc@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=linux-riscv@lists.infradead.org \
--cc=linux-sh@vger.kernel.org \
--cc=linux@armlinux.org.uk \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mattst88@gmail.com \
--cc=mingo@redhat.com \
--cc=monstr@monstr.eu \
--cc=mpe@ellerman.id.au \
--cc=palmer@dabbelt.com \
--cc=paul.walmsley@sifive.com \
--cc=rth@twiddle.net \
--cc=schnelle@linux.ibm.com \
--cc=sparclinux@vger.kernel.org \
--cc=tglx@linutronix.de \
--cc=tsbogend@alpha.franken.de \
--cc=will@kernel.org \
--cc=x86@kernel.org \
--cc=ysato@users.sourceforge.jp \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).