From: Bjorn Helgaas <helgaas@kernel.org>
To: John Garry <john.garry@huawei.com>
Cc: rjw@rjwysocki.net, wangkefeng.wang@huawei.com,
lorenzo.pieralisi@arm.com, arnd@arndb.de,
linux-pci@vger.kernel.org, will.deacon@arm.com,
linuxarm@huawei.com, linux-kernel@vger.kernel.org,
catalin.marinas@arm.com, andriy.shevchenko@linux.intel.com,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v4 1/3] lib: logic_pio: Use logical PIO low-level accessors for !CONFIG_INDIRECT_PIO
Date: Fri, 14 Jun 2019 06:50:56 -0500 [thread overview]
Message-ID: <20190614115056.GP13533@google.com> (raw)
In-Reply-To: <7495dcab-f293-4b2a-4740-2249f61351f7@huawei.com>
On Fri, Jun 14, 2019 at 10:02:52AM +0100, John Garry wrote:
> On 13/06/2019 21:09, Bjorn Helgaas wrote:
> > On Thu, Jun 13, 2019 at 10:39:12AM +0100, John Garry wrote:
> > > On 13/06/2019 03:39, Bjorn Helgaas wrote:
> > > > I'm not sure it's even safe, because CONFIG_INDIRECT_PIO depends on
> > > > ARM64, but PCI_IOBASE is defined on most arches via asm-generic/io.h,
> > > > so this potentially affects arches other than ARM64.
> > >
> > > It would do. It would affect any arch which defines PCI_IOBASE and
> > > does not have arch-specific definition of inb et all.
>
> > What's the reason for testing PCI_IOBASE instead of
> > CONFIG_INDIRECT_PIO? If there's a reason it's needed, that's fine,
> > but it does make this much more complicated to review.
>
> For ARM64, we have PCI_IOBASE defined but may not have
> CONFIG_INDIRECT_PIO defined. Currently CONFIG_INDIRECT_PIO is only
> selected by CONFIG_HISILICON_LPC.
>
> As such, we should make this change also for when
> CONFIG_INDIRECT_PIO is not defined.
OK. This is all very important for the commit log -- we need to
understand what arches are affected and the reason they need it.
Since the goal of this series is to fix an ARM64-specific issue, and
the typical port I/O model is for each arch to #define its own inb(),
maybe it would make sense to move the "#define inb logic_inb" from
linux/logic_pio.h to arm64/include/asm/io.h?
The "#ifndef inb" arrangement gets pretty complicated when it occurs
more than one place (asm-generic/io.h and logic_pio.h) and we have to
start worrying about the ordering of #includes.
Bjorn
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next prev parent reply other threads:[~2019-06-14 11:51 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-11 14:12 [PATCH v4 0/3] Fix ARM64 crash for accessing unmapped IO port regions John Garry
2019-06-11 14:12 ` [PATCH v4 1/3] lib: logic_pio: Use logical PIO low-level accessors for !CONFIG_INDIRECT_PIO John Garry
2019-06-13 2:39 ` Bjorn Helgaas
2019-06-13 9:39 ` John Garry
2019-06-13 20:09 ` Bjorn Helgaas
2019-06-14 9:02 ` John Garry
2019-06-14 11:50 ` Bjorn Helgaas [this message]
2019-06-14 12:22 ` John Garry
2019-06-13 13:58 ` Bjorn Helgaas
2019-06-13 15:21 ` John Garry
2019-06-11 14:12 ` [PATCH v4 2/3] lib: logic_pio: Reject accesses to unregistered CPU MMIO regions John Garry
2019-06-13 3:20 ` Bjorn Helgaas
2019-06-13 7:47 ` Arnd Bergmann
2019-06-13 10:17 ` John Garry
2019-06-13 13:46 ` Bjorn Helgaas
2019-06-13 14:09 ` John Garry
2019-06-11 14:12 ` [PATCH v4 3/3] lib: logic_pio: Fix up a print John Garry
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