powerpc/powernv: wire up rng during setup_arch

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: a4da0d50b2 ("powerpc: Implement arch_get_random_long/int() for powernv")
Cc: stable@vger.kernel.org # v3.13+
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[mpe: Add of_node_put(), use pnv naming, minor change log editing]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220621140849.127227-1-Jason@zx2c4.com
This commit is contained in:
Jason A. Donenfeld 2022-06-21 16:08:49 +02:00 committed by Michael Ellerman
parent ca5dabcff1
commit f3eac42665
3 changed files with 40 additions and 16 deletions

View File

@ -42,4 +42,6 @@ ssize_t memcons_copy(struct memcons *mc, char *to, loff_t pos, size_t count);
u32 __init memcons_get_size(struct memcons *mc);
struct memcons *__init memcons_init(struct device_node *node, const char *mc_prop_name);
void pnv_rng_init(void);
#endif /* _POWERNV_H */

View File

@ -17,6 +17,7 @@
#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/smp.h>
#include "powernv.h"
#define DARN_ERR 0xFFFFFFFFFFFFFFFFul
@ -28,7 +29,6 @@ struct powernv_rng {
static DEFINE_PER_CPU(struct powernv_rng *, powernv_rng);
int powernv_hwrng_present(void)
{
struct powernv_rng *rng;
@ -98,9 +98,6 @@ static int __init initialise_darn(void)
return 0;
}
}
pr_warn("Unable to use DARN for get_random_seed()\n");
return -EIO;
}
@ -163,32 +160,55 @@ 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);

View File

@ -203,6 +203,8 @@ static void __init pnv_setup_arch(void)
pnv_check_guarded_cores();
/* XXX PMCS */
pnv_rng_init();
}
static void __init pnv_init(void)