Re: [PATCH RESEND v4 1/1] tpm: add sysfs exports for all banks of PCR registers

[James Bottomley <James.Bottomley@HansenPartnership.com>]

On Mon, 2020-09-07 at 07:39 +0200, Greg KH wrote:
> On Sun, Sep 06, 2020 at 01:32:45PM -0700, James Bottomley wrote:
> > Create sysfs per hash groups with 24 PCR files in them one group,
> > named pcr-<hash>, for each agile hash of the TPM.  The files are
> > plugged in to a PCR read function which is TPM version agnostic, so
> > this works also for TPM 1.2 but the hash is only sha1 in that case.
> > 
> > Note: the macros used to create the hashes emit spurious checkpatch
> > warnings.  Do not try to "fix" them as checkpatch recommends,
> > otherwise
> > they'll break.
> 
> Oh you are just ensuring yourself a world of hurt for drive-by
> patches that everyone submits.  Don't do this if you can help it at
> all.

Well, what do you suggest: macros that generate macros can't use
brackets around the arguments because the macro generation becomes
wrong.  This is the thing that checkpatch is insisting on because the
usual fault people commit in macros that generate C code is forgetting
that unless you bracket the arguments in the macro they can have
unintended side effects.

James