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From: Nicholas Piggin <npiggin@gmail.com>
To: Segher Boessenkool <segher@kernel.crashing.org>
Cc: linuxppc-dev@ozlabs.org
Subject: Re: [PATCH v2 6/9] powerpc/microwatt: Add support for hardware random number generator
Date: Sun, 20 Jun 2021 18:19:39 +1000	[thread overview]
Message-ID: <1624176949.vsicfg0jsa.astroid@bobo.none> (raw)
In-Reply-To: <20210619143640.GX5077@gate.crashing.org>

Excerpts from Segher Boessenkool's message of June 20, 2021 12:36 am:
> On Sat, Jun 19, 2021 at 01:08:51PM +1000, Nicholas Piggin wrote:
>> Excerpts from Paul Mackerras's message of June 18, 2021 1:47 pm:
>> > Microwatt's hardware RNG is accessed using the DARN instruction.
>> 
>> I think we're getting a platforms/book3s soon with the VAS patches, 
>> might be a place to add the get_random_darn function.
>> 
>> Huh, DARN is unprivileged right?
> 
> It is, that's the whole point: to make it very very cheap for user
> software it has to be an unprivileged instruction.

Right, I was just doing a double-take. In that case we should enable it 
in the pseries random number code as well, so it really would be a 
generic isa 3.0 function that all (microwatt, powernv, pseries) could
use AFAIKS.

Thanks,
Nick

  reply	other threads:[~2021-06-20  8:20 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-18  3:42 [PATCH v2 0/9] powerpc: Add support for Microwatt soft-core Paul Mackerras
2021-06-18  3:43 ` [PATCH v2 1/9] powerpc: Add Microwatt platform Paul Mackerras
2021-06-19  3:03   ` Nicholas Piggin
2021-06-18  3:44 ` [PATCH v2 2/9] powerpc: Add Microwatt device tree Paul Mackerras
2021-06-19 14:26   ` Segher Boessenkool
2021-06-20 12:08     ` Paul Mackerras
2021-06-21 13:54       ` Segher Boessenkool
2021-06-18  3:45 ` [PATCH v2 3/9] powerpc/microwatt: Populate platform bus from device-tree Paul Mackerras
2021-06-18  3:45 ` [PATCH v2 4/9] powerpc/xics: Add a native ICS backend for microwatt Paul Mackerras
2021-06-18  3:46 ` [PATCH v2 5/9] powerpc/microwatt: Use standard 16550 UART for console Paul Mackerras
2021-06-18  7:40   ` Nicholas Piggin
2021-06-18 12:12     ` Paul Mackerras
2021-06-19  2:58       ` Nicholas Piggin
2021-08-12 13:14   ` Christophe Leroy
2021-08-12 16:09     ` Segher Boessenkool
2021-06-18  3:47 ` [PATCH v2 6/9] powerpc/microwatt: Add support for hardware random number generator Paul Mackerras
2021-06-19  3:08   ` Nicholas Piggin
2021-06-19 14:36     ` Segher Boessenkool
2021-06-20  8:19       ` Nicholas Piggin [this message]
2021-06-18  3:48 ` [PATCH v2 7/9] powerpc/microwatt: Add microwatt_defconfig Paul Mackerras
2021-06-18  3:49 ` [PATCH v2 8/9] powerpc/boot: Fixup device-tree on little endian Paul Mackerras
2021-06-19  3:14   ` Nicholas Piggin
2021-06-18  3:49 ` [PATCH v2 9/9] powerpc/boot: Add a boot wrapper for Microwatt Paul Mackerras
2021-06-19  3:16   ` Nicholas Piggin
2021-06-19 14:45 ` [PATCH v2 0/9] powerpc: Add support for Microwatt soft-core Segher Boessenkool
2021-06-24 14:03 ` Michael Ellerman

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