Re: randconfig build error with next-20150529, in crypto/jitterentropy.c

From: Stephan Mueller
Date: Mon Jun 08 2015 - 11:53:09 EST


Am Monday 08 June 2015, 14:36:30 schrieb Peter Zijlstra:

Hi Peter,
>
>Would something like
>
>#pragma GCC push_options
>#pragma GCC optimize ("-O0")
>static __u64 jent_fold_time(struct rand_data *ec, __u64 time,
> __u64 *folded, __u64 loop_cnt)
>{
> ...
>}
>#pragma GCC pop_options
>
>Be an option to allow the file to be compiled with regular optimizations
>enabled?

After doing some tests, I see that neither the min entropy nor the Shannon
Entropy of the raw noise is affected by using the mentioned pragmas at the
right locations.

So I will prepare a patch tonight.

Just for my edification: why does an -O0 on a self contained file break the
compile run? Any why do the pragmas work?

Thanks
Stephan
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