From: "Luck, Tony" <tony.luck@intel.com>
To: Borislav Petkov <bp@amd64.org>,
        "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
CC: LKML <linux-kernel@vger.kernel.org>,
        Borislav Petkov <borislav.petkov@amd.com>
Subject: RE: [RFC PATCH 3/3] Convert mce_disabled
Thread-Topic: [RFC PATCH 3/3] Convert mce_disabled
Thread-Index: AQHNpvJoe4YCF/JU9UKk6x+JHaLQpZe19koAgAASYwD//+j0oA==
Date: Fri, 12 Oct 2012 17:46:16 +0000
Message-ID: <3908561D78D1C84285E8C5FCA982C28F19D4ABDA@ORSMSX108.amr.corp.intel.com>
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 <5077F600.9090605@linux.vnet.ibm.com>
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> Or, you can modify the mca_config I have there and use bools and pass a
> pointer to each actual bool member in each DEVICE_BIT_ATTR invocation
> (and rename it to DEVICE_BOOL_ATTR). Yeah, that could work, unless I'm
> missing something else, of course.

This looks like the best solution to me. Sure we use a little more memory for
a "bool" for each option instead of just a single bit. But there are only a
handful of them, not thousands. So I think we can cope with a few extra
bytes of memory consumption.  I was still not completely convinced by the

       if (val)
               *bvec |= le64_to_cpu(BIT_64(bit));

solution - it assumes that big endian machines also assign their bit numbers
in a big->little way - but that isn't required by the C standard. bitfields are
assigned at the whim of the compiler writer (the only restrictions seem to
be on alignments of fields w.r.t. to the underlying data types).

-Tony
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