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

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On 23/03/2019 19:15, Andy Shevchenko wrote:
On Wed, Mar 20, 2019 at 8:14 PM John Garry <john.garry@xxxxxxxxxx> 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:



Hi Andy,


 #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) \

Sure, I can change that if you think it reads better.

 (...)

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

Can it fit one line?

It should be ok. I can shorten some variable names.



Thanks for checking,
John




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