Re: [PATCH 2/2] misc: Add Xilinx PUF driver

[Jain, Harsh (AECG-SSW)]

On 7/7/2026 3:34 PM, Arnd Bergmann wrote:
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>
>
> On Tue, Jul 7, 2026, at 11:56, Harsh Jain wrote:
> > Versal devices contain a physically unclonable function (PUF) block
> > that derives device-unique secrets from intrinsic silicon
> > characteristics. The PUF generates a Key Encryption Key (KEK) used
> > internally by the AES engine for secure key storage, which is not
> > externally accessible. In addition, the PUF provides a readable
> > device-unique identifier derived from the same entropy source.
> >
> > Add a misc character driver to support PUF registration and regeneration.
> > Registration generates a unique secret and outputs binary helper data
> > that can later be used during regeneration to reproduce the same
> > secrets.
> >
> > The driver also implements PUF_CLEAR_ID and PUF_CLEAR_KEY ioctls to clear
> > the PUF ID and PUF-derived AES key via firmware. They are disabled by default
> > unless puf_clear is set.
> >
> > Signed-off-by: Harsh Jain <h.jain@xxxxxxx>
> Hi Harsh,
>
> This description sounds like it should be integrated into the
> existing crypto infrastructure of the kernel. I'm not sure
> what the exact feature set in your hardware is like, but
> please work with the crypto and keyctl maintainers to either
> use that infrastructure, or extend it to your requirements
> instead of adding a custom ioctl interface.
>
> My guess would be that you can have a driver similar
> to drivers/platform/cznic/turris-omnia-mcu-keyctl.c
> for managing private keys in the hardware and managing
> it through the keyctl(2) infrastructure. Have you looked
> at this already?

Thanks Arnd for quick feedback. I will check the mentioned subsystem.


>        Arnd