linux-kernel - Re: [PATCH v2 2/3] lib: logic_pio: Reject access to unregistered CPU MMIO regions

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Message-ID: <CAHp75VfRwp+XGdE6k4KU6hvLNu=h3TRVbm5AFOAZgsp-i1Ehjg@mail.gmail.com>
Date:   Sat, 23 Mar 2019 21:15:38 +0200
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     John Garry <john.garry@...wei.com>
Cc:     Bjorn Helgaas <bhelgaas@...gle.com>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Arnd Bergmann <arnd@...db.de>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Borislav Petkov <bp@...e.de>,
        Guenter Roeck <linux@...ck-us.net>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-pci@...r.kernel.org,
        Kefeng Wang <wangkefeng.wang@...wei.com>,
        Linuxarm <linuxarm@...wei.com>, Alexander Graf <agraf@...e.de>
Subject: Re: [PATCH v2 2/3] lib: logic_pio: Reject access to unregistered CPU
 MMIO regions

On Wed, Mar 20, 2019 at 8:14 PM John Garry <john.garry@...wei.com> wrote:
>
> Currently when accessing logical indirect PIO addresses in
> logic_{in, out}{,s}, we first ensure that the region is registered.
>
> However, no such check exists for CPU MMIO regions. The CPU MMIO regions
> would be registered by the PCI host (when PCI_IOBASE is defined) in
> pci_register_io_range().
>
> We have seen scenarios when systems which don't have a PCI host or, they
> do, and the PCI host probe fails, that certain devices attempts to still
> attempt to access PCI IO ports; examples are in [1] and [2].
>
> And even though we would protect against this by ensuring the driver call
> request_{muxed_}region(), some don't do this:
>


>  #if defined(CONFIG_INDIRECT_PIO) && defined(PCI_IOBASE)
> +#define INVALID_RANGE(range) (!range || \
> +                             (range->flags == LOGIC_PIO_CPU_MMIO && !range->ops))

It would be better to read in a form
#define foo(x) \
 (...)

> +               ret = range->ops->in(range->hostdata,                   \
> +                                    addr, sizeof(type));               \

Can it fit one line?

-- 
With Best Regards,
Andy Shevchenko