Re: [PATCH v5 10/11] xtensa: use fallback for random_get_entropy() instead of zero

From: Max Filippov <jcmvbkbc@gmail.com>
To: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	linux-crypto@vger.kernel.org,
	 Thomas Gleixner <tglx@linutronix.de>,
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	 "H . Peter Anvin" <hpa@zytor.com>,
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Subject: Re: [PATCH v5 10/11] xtensa: use fallback for random_get_entropy() instead of zero
Date: Thu, 21 Apr 2022 01:00:36 -0700	[thread overview]
Message-ID: <CAMo8Bf+ox2MQRkqsTaOOXOchOWpb+7P8GQ1c-TjwSpDgttXoFA@mail.gmail.com> (raw)
In-Reply-To: <20220419111650.1582274-11-Jason@zx2c4.com>

On Tue, Apr 19, 2022 at 4:18 AM Jason A. Donenfeld <Jason@zx2c4.com> 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.
>
> This is accomplished by just including the asm-generic code like on
> other architectures, which means we can get rid of the empty stub
> function here.
>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Max Filippov <jcmvbkbc@gmail.com>
> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
> ---
>  arch/xtensa/include/asm/timex.h | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)

Acked-by: Max Filippov <jcmvbkbc@gmail.com>

-- 
Thanks.
-- Max

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