Re: [PATCH] crypto: jitterentropy - bind statically into kernel

[Palmer Dabbelt]

On Sun, 04 Oct 2020 14:16:10 PDT (-0700), ardb@xxxxxxxxxx wrote:
> On Sun, 4 Oct 2020 at 20:48, Stephan Müller <smueller@xxxxxxxxxx> wrote:
> > The RISC-V architecture is about to implement the callback
> > random_get_entropy with a function that is not exported to modules.
>
> Why is that? Wouldn't it be better to export the symbol instead?

It's static inline (in our timex.h), so I thought we didn't need to export the
symbol?  Did this just arise because clint_time_val wasn't exported?  That was
fixed before the random_get_entropy() change landed in Linus' tree, so as far
as I know we should be OK here.

If I broke something here it seem better to fix this in the RISC-V port than by
just banning modular compilation of jitterentropy, as that seems like a useful
feature to me.

> > Thus, the Jitter RNG is changed to be only bound statically into the
> > kernel removing the option to compile it as module.
> >
> > Reported-by: Christoph Hellwig <hch@xxxxxxxxxxxxx>
> > Signed-off-by: Stephan Mueller <smueller@xxxxxxxxxx>
> > ---
> >  crypto/Kconfig | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/crypto/Kconfig b/crypto/Kconfig
> > index 094ef56ab7b4..5b20087b117f 100644
> > --- a/crypto/Kconfig
> > +++ b/crypto/Kconfig
> > @@ -1853,7 +1853,7 @@ config CRYPTO_DRBG
> >  endif  # if CRYPTO_DRBG_MENU
> >
> >  config CRYPTO_JITTERENTROPY
> > -       tristate "Jitterentropy Non-Deterministic Random Number Generator"
> > +       bool "Jitterentropy Non-Deterministic Random Number Generator"
> >         select CRYPTO_RNG
> >         help
> >           The Jitterentropy RNG is a noise that is intended
> > --
> > 2.26.2