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Commit 7e53f5da authored by Jason A. Donenfeld's avatar Jason A. Donenfeld Committed by Greg Kroah-Hartman
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powerpc/powernv: wire up rng during setup_arch 



commit f3eac426657d985b97c92fa5f7ae1d43f04721f3 upstream.

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.

Complicating things, however, is that POWER8 systems need some per-cpu
state and kmalloc, which isn't available at this stage. So we split
things up into an early phase and a later opportunistic phase. This
commit also removes some noisy log messages that don't add much.

Fixes: a4da0d50 ("powerpc: Implement arch_get_random_long/int() for powernv")
Cc: stable@vger.kernel.org # v3.13+
Signed-off-by: default avatarJason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
[mpe: Add of_node_put(), use pnv naming, minor change log editing]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220621140849.127227-1-Jason@zx2c4.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 26b64089

arch/powerpc/platforms/powernv/powernv.h

+2 −0
Original line number Diff line number Diff line
@@ -30,4 +30,6 @@ extern void opal_event_shutdown(void); 


bool cpu_core_split_required(void);



void pnv_rng_init(void);



#endif /* _POWERNV_H */

arch/powerpc/platforms/powernv/rng.c

+36 −16
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <asm/prom.h>

#include <asm/machdep.h>

#include <asm/smp.h>

#include "powernv.h"



#define DARN_ERR 0xFFFFFFFFFFFFFFFFul
@@ -32,7 +33,6 @@ struct powernv_rng { 


static DEFINE_PER_CPU(struct powernv_rng *, powernv_rng);





int powernv_hwrng_present(void)

{

	struct powernv_rng *rng;
@@ -102,9 +102,6 @@ static int initialise_darn(void) 
			return 0;

		}

	}



	pr_warn("Unable to use DARN for get_random_seed()\n");



	return -EIO;

}
@@ -167,32 +164,55 @@ static __init int rng_create(struct device_node *dn) 


	rng_init_per_cpu(rng, dn);



	pr_info_once("Registering arch random hook.\n");



	ppc_md.get_random_seed = powernv_get_random_long;



	return 0;

}



static __init int rng_init(void)

static int __init pnv_get_random_long_early(unsigned long *v)

{

	struct device_node *dn;

	int rc;



	if (!slab_is_available())

		return 0;



	if (cmpxchg(&ppc_md.get_random_seed, pnv_get_random_long_early,

		    NULL) != pnv_get_random_long_early)

		return 0;



	for_each_compatible_node(dn, NULL, "ibm,power-rng") {

		rc = rng_create(dn);

		if (rc) {

			pr_err("Failed creating rng for %pOF (%d).\n",

				dn, rc);

		if (rng_create(dn))

			continue;

		}



		/* Create devices for hwrng driver */

		of_platform_device_create(dn, NULL, NULL);

	}



	initialise_darn();

	if (!ppc_md.get_random_seed)

		return 0;

	return ppc_md.get_random_seed(v);

}



void __init pnv_rng_init(void)

{

	struct device_node *dn;



	/* Prefer darn over the rest. */

	if (!initialise_darn())

		return;



	dn = of_find_compatible_node(NULL, NULL, "ibm,power-rng");

	if (dn)

		ppc_md.get_random_seed = pnv_get_random_long_early;



	of_node_put(dn);

}



static int __init pnv_rng_late_init(void)

{

	unsigned long v;

	/* In case it wasn't called during init for some other reason. */

	if (ppc_md.get_random_seed == pnv_get_random_long_early)

		pnv_get_random_long_early(&v);

	return 0;

}

machine_subsys_initcall(powernv, rng_init);
 
machine_subsys_initcall(powernv, pnv_rng_late_init);

arch/powerpc/platforms/powernv/setup.c

+2 −0
Original line number Diff line number Diff line
@@ -171,6 +171,8 @@ static void __init pnv_setup_arch(void) 
	powersave_nap = 1;



	/* XXX PMCS */



	pnv_rng_init();

}



static void __init pnv_init(void)