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

From: John Garry
Date: Mon Mar 25 2019 - 05:59:42 EST

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

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,