linux-stable.git/include/asm-generic/io.h, branch linux-5.4.y

asm-generic/io.h: suppress endianness warnings for readq() and writeq()

2023-05-17T09:35:32+00:00

[ Upstream commit d564fa1ff19e893e2971d66e5c8f49dc1cdc8ffc ]

Commit c1d55d50139b ("asm-generic/io.h: Fix sparse warnings on
big-endian architectures") missed fixing the 64-bit accessors.

Arnd explains in the attached link why the casts are necessary, even if
__raw_readq() and __raw_writeq() do not take endian-specific types.

Link: https://lore.kernel.org/lkml/9105d6fc-880b-4734-857d-e3d30b87ccf6@app.fastmail.com/
Suggested-by: Arnd Bergmann 
Signed-off-by: Vladimir Oltean 
Reviewed-by: Jonathan Cameron 
Signed-off-by: Arnd Bergmann 
Signed-off-by: Sasha Levin

asm-generic: don't provide __ioremap

2019-08-30T19:46:27+00:00

__ioremap is not a kernel API, but used for helpers with differing
semantics in arch code.  We should not provide it in as-generic.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Paul Walmsley 
Tested-by: Paul Walmsley  # rv32, rv64 boot
Acked-by: Paul Walmsley  # arch/riscv
Signed-off-by: Arnd Bergmann

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36

2019-05-24T15:27:11+00:00

Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public licence as published by
  the free software foundation either version 2 of the licence or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 114 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Allison Randal 
Reviewed-by: Kate Stewart 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520170857.552531963@linutronix.de
Signed-off-by: Greg Kroah-Hartman

arch: Remove dummy mmiowb() definitions from arch code

2019-04-08T11:09:27+00:00

Now that no driver code is using mmiowb() directly, remove the dummy
definitions remaining in architectures that don't make use of
asm-generic/io.h, as well as the definition in asm-generic/io.h itself.

Acked-by: Linus Torvalds 
Signed-off-by: Will Deacon

mmiowb: Hook up mmiowb helpers to spinlocks and generic I/O accessors

2019-04-08T10:59:47+00:00

Removing explicit calls to mmiowb() from driver code means that we must
now call into the generic mmiowb_spin_{lock,unlock}() functions from the
core spinlock code. In order to elide barriers following critical
sections without any I/O writes, we also hook into the asm-generic I/O
routines.

Acked-by: Linus Torvalds 
Signed-off-by: Will Deacon

asm-generic/io: Pass result of I/O accessor to __io_[p]ar()

2019-02-28T17:22:47+00:00

The inX() and readX() I/O accessors must enforce ordering against
subsequent calls to the delay() routines, so that a read-back from a
device can be used to postpone a subsequent write to the same device.

On some architectures, including arm64, this ordering can only be
achieved by creating a dependency on the value returned by the I/O
accessor operation, so we need to pass the value we read to the
__io_par() and __io_ar() macros in these cases.

Acked-by: Arnd Bergmann 
Reported-by: Andrew Murray 
Reviewed-by: Palmer Dabbelt 
Signed-off-by: Will Deacon 
Signed-off-by: Catalin Marinas

asm-generic: io: Fix ioport_map() for !CONFIG_GENERIC_IOMAP && CONFIG_INDIRECT_PIO

2018-09-14T08:49:21+00:00

The !CONFIG_GENERIC_IOMAP version of ioport_map uses MMIO_UPPER_LIMIT to
prevent users from making I/O accesses outside the expected I/O range -
however it erroneously treats MMIO_UPPER_LIMIT as a mask which is
contradictory to its other users.

The introduction of CONFIG_INDIRECT_PIO, which subtracts an arbitrary
amount from IO_SPACE_LIMIT to form MMIO_UPPER_LIMIT, results in ioport_map
mangling the given port rather than capping it.

We address this by aligning more closely with the CONFIG_GENERIC_IOMAP
implementation of ioport_map by using the comparison operator and
returning NULL where the port exceeds MMIO_UPPER_LIMIT. Though note that
we preserve the existing behavior of masking with IO_SPACE_LIMIT such that
we don't break existing buggy drivers that somehow rely on this masking.

Fixes: 5745392e0c2b ("PCI: Apply the new generic I/O management on PCI IO hosts")
Reported-by: Will Deacon 
Reviewed-by: Arnd Bergmann 
Signed-off-by: Andrew Murray 
Signed-off-by: Will Deacon

Merge tag 'asm-generic' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

2018-04-12T16:15:48+00:00

Pull asm-generic fixes from Arnd Bergmann:
 "I have one regression fix for a minor build problem after the
  architecture removal series, plus a rework of the barriers in the
  readl/writel functions, thanks to work by Sinan Kaya:

  This started from a discussion on the linuxpcc and rdma mailing
  lists[1]. To summarize, we decided that architectures are responsible
  to serialize readl() and writel() accesses on a device MMIO space
  relative to DMA performed by that device.

  This series provides a pessimistic implementation of that behavior for
  asm-generic/io.h, which is in turn used by a number of architectures
  (h8300, microblaze, nios2, openrisc, s390, sparc, um, unicore32, and
  xtensa). Some of those presumably need no extra barriers, or something
  weaker than rmb()/wmb(), and they are advised to override the new
  default for better performance.

  For inb()/outb(), the same barriers are used, but architectures might
  want to add another barrier to outb() here if that can guarantee
  non-posted behavior (some architectures can, others cannot do that).

  The readl_relaxed()/writel_relaxed() family of functions retains the
  existing behavior with no extra barriers"

[1] https://lists.ozlabs.org/pipermail/linuxppc-dev/2018-March/170481.html

* tag 'asm-generic' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  io: change writeX_relaxed() to remove barriers
  io: change readX_relaxed() to remove barriers
  dts: remove cris & metag dts hard link file
  io: change inX() to have their own IO barrier overrides
  io: change outX() to have their own IO barrier overrides
  io: define stronger ordering for the default writeX() implementation
  io: define stronger ordering for the default readX() implementation
  io: define several IO & PIO barrier types for the asm-generic version

io: change writeX_relaxed() to remove barriers

2018-04-10T14:37:34+00:00

Now that we hardened writeX() API in asm-generic version, writeX_relaxed()
API is violating the rules when writeX_relaxed() == writeX() in the default
implementation.

The relaxed API shouldn't have any barriers in it and it doesn't provide
any ordering with respect to the memory transactions. The only requirement
is for writes to be ordered with respect to each other. This is achieved
by the volatile in the __raw_writeX() API.

Open code the relaxed API and remove any barriers in it.

Signed-off-by: Sinan Kaya 
Signed-off-by: Arnd Bergmann

io: change readX_relaxed() to remove barriers

2018-04-10T14:37:21+00:00

Now that we hardened readX() API in asm-generic version, readX_relaxed()
API is violating the rules when readX_relaxed() == readX() in the default
implementation.

The relaxed API shouldn't have any barriers in it and it doesn't provide
any ordering with respect to the memory transactions. The only requirement
is for reads to be ordered with respect to each other. This is achieved
by the volatile in the __raw_readX() API.

Open code the relaxed API and remove any barriers in it.

Signed-off-by: Sinan Kaya 
Signed-off-by: Arnd Bergmann