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20a9689b36
The platform's RNG must be available before random_init() in order to be
useful for initial seeding, which in turn means that it needs to be
called from setup_arch(), rather than from an init call. Fortunately,
each platform already has a setup_arch function pointer, which means
it's easy to wire this up. This commit also removes some noisy log
messages that don't add much.
Fixes: c25769fdda ("powerpc/microwatt: Add support for hardware random number generator")
Cc: stable@vger.kernel.org # v5.14+
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220611151015.548325-2-Jason@zx2c4.com
45 lines
863 B
C
45 lines
863 B
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Derived from arch/powerpc/platforms/powernv/rng.c, which is:
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* Copyright 2013, Michael Ellerman, IBM Corporation.
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*/
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#define pr_fmt(fmt) "microwatt-rng: " fmt
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#include <linux/kernel.h>
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#include <linux/smp.h>
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#include <asm/archrandom.h>
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#include <asm/cputable.h>
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#include <asm/machdep.h>
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#include "microwatt.h"
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#define DARN_ERR 0xFFFFFFFFFFFFFFFFul
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static int microwatt_get_random_darn(unsigned long *v)
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{
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unsigned long val;
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/* Using DARN with L=1 - 64-bit conditioned random number */
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asm volatile(PPC_DARN(%0, 1) : "=r"(val));
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if (val == DARN_ERR)
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return 0;
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*v = val;
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return 1;
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}
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void __init microwatt_rng_init(void)
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{
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unsigned long val;
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int i;
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for (i = 0; i < 10; i++) {
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if (microwatt_get_random_darn(&val)) {
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ppc_md.get_random_seed = microwatt_get_random_darn;
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return;
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}
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}
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}
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