Re: Security Random Number Generator support

[Marc Zyngier]

On 2020-06-02 13:14, Ard Biesheuvel wrote:
> On Tue, 2 Jun 2020 at 10:15, Neal Liu <neal.liu@xxxxxxxxxxxx> wrote:
> > These patch series introduce a security random number generator
> > which provides a generic interface to get hardware rnd from Secure
> > state. The Secure state can be Arm Trusted Firmware(ATF), Trusted
> > Execution Environment(TEE), or even EL2 hypervisor.
> >
> > Patch #1..2 adds sec-rng kernel driver for Trustzone based SoCs.
> > For security awareness SoCs on ARMv8 with TrustZone enabled,
> > peripherals like entropy sources is not accessible from normal world
> > (linux) and rather accessible from secure world (HYP/ATF/TEE) only.
> > This driver aims to provide a generic interface to Arm Trusted
> > Firmware or Hypervisor rng service.
> >
> >
> > changes since v1:
> > - rename mt67xx-rng to mtk-sec-rng since all MediaTek ARMv8 SoCs can 
> > reuse
> >   this driver.
> >   - refine coding style and unnecessary check.
> >
> >   changes since v2:
> >   - remove unused comments.
> >   - remove redundant variable.
> >
> >   changes since v3:
> >   - add dt-bindings for MediaTek rng with TrustZone enabled.
> >   - revise HWRNG SMC call fid.
> >
> >   changes since v4:
> >   - move bindings to the arm/firmware directory.
> >   - revise driver init flow to check more property.
> >
> >   changes since v5:
> >   - refactor to more generic security rng driver which
> >     is not platform specific.
> >
> > *** BLURB HERE ***
> >
> > Neal Liu (2):
> >   dt-bindings: rng: add bindings for sec-rng
> >   hwrng: add sec-rng driver
>
> There is no reason to model a SMC call as a driver, and represent it
> via a DT node like this.

+1.

> It would be much better if this SMC interface is made truly generic,
> and wired into the arch_get_random() interface, which can be used much
> earlier.

Wasn't there a plan to standardize a SMC call to rule them all?

        M.
--
Who you jivin' with that Cosmik Debris?