From: Jason A. Donenfeld Jason@zx2c4.com
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: a4da0d50b2a0 ("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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/powerpc/platforms/powernv/powernv.h | 2 + arch/powerpc/platforms/powernv/rng.c | 52 +++++++++++++++++++++---------- arch/powerpc/platforms/powernv/setup.c | 2 + 3 files changed, 40 insertions(+), 16 deletions(-)
--- a/arch/powerpc/platforms/powernv/powernv.h +++ b/arch/powerpc/platforms/powernv/powernv.h @@ -42,4 +42,6 @@ ssize_t memcons_copy(struct memcons *mc, u32 memcons_get_size(struct memcons *mc); struct memcons *memcons_init(struct device_node *node, const char *mc_prop_name);
+void pnv_rng_init(void); + #endif /* _POWERNV_H */ --- a/arch/powerpc/platforms/powernv/rng.c +++ b/arch/powerpc/platforms/powernv/rng.c @@ -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 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 devi
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); --- a/arch/powerpc/platforms/powernv/setup.c +++ b/arch/powerpc/platforms/powernv/setup.c @@ -190,6 +190,8 @@ static void __init pnv_setup_arch(void) pnv_check_guarded_cores();
/* XXX PMCS */ + + pnv_rng_init(); }
static void __init pnv_init(void)