linux-kernel - Re: [PATCH v2 5/6] tpm: add driver for cr50 on SPI

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <5d2f5570.1c69fb81.f3832.3c3f@mx.google.com>
Date:   Wed, 17 Jul 2019 10:05:52 -0700
From:   Stephen Boyd <swboyd@...omium.org>
To:     Jason Gunthorpe <jgg@...pe.ca>
Cc:     Alexander Steffen <Alexander.Steffen@...ineon.com>,
        Peter Huewe <peterhuewe@....de>,
        Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        Andrey Pronin <apronin@...omium.org>,
        linux-kernel@...r.kernel.org, Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-integrity@...r.kernel.org,
        Duncan Laurie <dlaurie@...omium.org>,
        Guenter Roeck <groeck@...omium.org>
Subject: Re: [PATCH v2 5/6] tpm: add driver for cr50 on SPI

Quoting Jason Gunthorpe (2019-07-17 09:56:28)
> On Wed, Jul 17, 2019 at 09:49:42AM -0700, Stephen Boyd wrote:
> > Quoting Jason Gunthorpe (2019-07-17 05:25:58)
> > > On Wed, Jul 17, 2019 at 02:00:06PM +0200, Alexander Steffen wrote:
> > > > On 17.07.2019 00:45, Stephen Boyd wrote:
> > > 
> > > But overall, it might be better to just double link the little helper:
> > > 
> > > obj-$(CONFIG_TCG_CR50_SPI) += cr50.o cr50_spi.o
> > > obj-$(CONFIG_TCG_CR50_I2C) += cr50.o cr50_i2c.o
> > > 
> > > As we don't actually ever expect to load both modules into the same
> > > system
> > > 
> > 
> > Sometimes we have both drivers built-in. To maintain the tiny space
> > savings I'd prefer to just leave this as helpless and tristate.
> 
> If it is builtin you only get one copy of cr50.o anyhow. The only
> differences is for modules, then the two modules will both be a bit
> bigger instead of a 3rd module being created
> 

Yes. The space savings comes from having the extra module 'cr50.ko' that
holds almost nothing at all when the two drivers are modules.