Messages in this thread |  | | Date | Mon, 23 May 2022 08:56:56 -0500 | Subject | Re: [PATCH v6 12/17] nios2: use fallback for random_get_entropy() instead of zero | From | Dinh Nguyen <> |
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On 4/23/22 16:26, Jason A. Donenfeld wrote: > In the event that random_get_entropy() can't access a cycle counter or > similar, falling back to returning 0 is really not the best we can do. > Instead, at least calling random_get_entropy_fallback() would be > preferable, because that always needs to return _something_, even > falling back to jiffies eventually. It's not as though > random_get_entropy_fallback() is super high precision or guaranteed to > be entropic, but basically anything that's not zero all the time is > better than returning zero all the time. > > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Arnd Bergmann <arnd@arndb.de> > Cc: Dinh Nguyen <dinguyen@kernel.org> > Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> > --- > arch/nios2/include/asm/timex.h | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/nios2/include/asm/timex.h b/arch/nios2/include/asm/timex.h > index a769f871b28d..40a1adc9bd03 100644 > --- a/arch/nios2/include/asm/timex.h > +++ b/arch/nios2/include/asm/timex.h > @@ -8,5 +8,8 @@ > typedef unsigned long cycles_t; > > extern cycles_t get_cycles(void); > +#define get_cycles get_cycles > + > +#define random_get_entropy() (((unsigned long)get_cycles()) ?: random_get_entropy_fallback()) > > #endif
Acked-by: Dinh Nguyen <dinguyen@kernel.org>
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