From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: Sandy Harris <sandyinchina@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Arnd Bergmann <arnd@arndb.de>, Theodore Ts'o <tytso@mit.edu>,
Dominik Brodowski <linux@dominikbrodowski.net>,
Russell King <linux@armlinux.org.uk>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
"David S . Miller" <davem@davemloft.net>,
Richard Weinberger <richard@nod.at>,
Anton Ivanov <anton.ivanov@cambridgegreys.com>,
Johannes Berg <johannes@sipsolutions.net>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H . Peter Anvin" <hpa@zytor.com>,
Chris Zankel <chris@zankel.net>,
Max Filippov <jcmvbkbc@gmail.com>,
Stephen Boyd <sboyd@kernel.org>,
Dinh Nguyen <dinguyen@kernel.org>,
linux-arm-kernel@lists.infradead.org,
linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org,
linux-riscv@lists.infradead.org, sparclinux@vger.kernel.org,
linux-um@lists.infradead.org, x86@kernel.org,
linux-xtensa@linux-xtensa.org
Subject: Re: [PATCH v5 11/11] random: insist on random_get_entropy() existing in order to simplify
Date: Sat, 23 Apr 2022 12:00:33 +0200 [thread overview]
Message-ID: <YmPOQS9GvdiM2brX@zx2c4.com> (raw)
In-Reply-To: <CACXcFmksd3cw+xa-c2gEdd4=96PO8GCCMF6q2d6JHnJum2LjiA@mail.gmail.com>
Hi Sandy,
On Sat, Apr 23, 2022 at 10:24:07AM +0800, Sandy Harris wrote:
> On Sat, Apr 23, 2022 at 6:37 AM Jason A. Donenfeld <Jason@zx2c4.com> wrote:
> >
> > All platforms are now guaranteed to provide some value for
> > random_get_entropy(). In case some bug leads to this not being so, we
> > print a warning, ...
>
> Would it make sense to test at compile time? If there is no hardware
> RNG nor a cycle counter, then the kernel should be compiled with
> the gcc latent entropy plugin. Generate a warning suggesting that,
> or even an error insisting on it.
Unfortunately, as a last ditch warning safeguard against bugs, I don't
think that's something we can determine at build time. A lot of this
machinery is dynamic. Fortunately a single check at init time brings
with it zero appreciable overhead.
Jason
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prev parent reply other threads:[~2022-04-23 10:02 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-19 11:16 [PATCH v5 00/11] archs/random: fallback to best raw ktime when no cycle counter Jason A. Donenfeld
2022-04-19 11:16 ` [PATCH v5 01/11] timekeeping: add raw clock fallback for random_get_entropy() Jason A. Donenfeld
2022-04-19 11:16 ` [PATCH v5 02/11] m68k: use fallback for random_get_entropy() instead of zero Jason A. Donenfeld
2022-04-19 11:16 ` [PATCH v5 03/11] riscv: " Jason A. Donenfeld
2022-04-19 11:16 ` [PATCH v5 04/11] mips: use fallback for random_get_entropy() instead of just c0 random Jason A. Donenfeld
2022-04-21 19:25 ` Maciej W. Rozycki
2022-04-21 20:01 ` Jason A. Donenfeld
2022-04-21 21:05 ` Thomas Bogendoerfer
2022-04-19 11:16 ` [PATCH v5 05/11] arm: use fallback for random_get_entropy() instead of zero Jason A. Donenfeld
2022-04-19 11:16 ` [PATCH v5 06/11] nios2: " Jason A. Donenfeld
2022-05-02 21:01 ` Dinh Nguyen
2022-04-19 11:16 ` [PATCH v5 07/11] x86: " Jason A. Donenfeld
2022-04-19 18:16 ` Borislav Petkov
2022-04-19 18:38 ` Jason A. Donenfeld
2022-04-19 18:59 ` Borislav Petkov
2022-04-19 19:00 ` Jason A. Donenfeld
2022-04-19 11:16 ` [PATCH v5 08/11] um: " Jason A. Donenfeld
2022-04-19 11:33 ` Johannes Berg
2022-04-19 11:37 ` Jason A. Donenfeld
2022-04-19 11:16 ` [PATCH v5 09/11] sparc: " Jason A. Donenfeld
2022-04-19 11:16 ` [PATCH v5 10/11] xtensa: " Jason A. Donenfeld
2022-04-21 8:00 ` Max Filippov
2022-04-19 11:16 ` [PATCH v5 11/11] random: insist on random_get_entropy() existing in order to simplify Jason A. Donenfeld
2022-04-23 2:24 ` Sandy Harris
2022-04-23 10:00 ` Jason A. Donenfeld [this message]
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