From f3eac426657d985b97c92fa5f7ae1d43f04721f3 Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Tue, 21 Jun 2022 16:08:49 +0200 Subject: 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: a4da0d50b2a0 ("powerpc: Implement arch_get_random_long/int() for powernv") Cc: stable@vger.kernel.org # v3.13+ Signed-off-by: Jason A. Donenfeld Reviewed-by: Christophe Leroy [mpe: Add of_node_put(), use pnv naming, minor change log editing] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220621140849.127227-1-Jason@zx2c4.com --- arch/powerpc/platforms/powernv/rng.c | 52 +++++++++++++++++++++++++----------- 1 file changed, 36 insertions(+), 16 deletions(-) (limited to 'arch/powerpc/platforms/powernv/rng.c') diff --git a/arch/powerpc/platforms/powernv/rng.c b/arch/powerpc/platforms/powernv/rng.c index e3d44b36ae98..463c78c52cc5 100644 --- a/arch/powerpc/platforms/powernv/rng.c +++ b/arch/powerpc/platforms/powernv/rng.c @@ -17,6 +17,7 @@ #include #include #include +#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); -- cgit v1.2.3-59-g8ed1b From 887502826549caa7e4215fd9e628f48f14c0825a Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Thu, 30 Jun 2022 14:16:54 +0200 Subject: powerpc/powernv: delay rng platform device creation until later in boot The platform device for the rng must be created much later in boot. Otherwise it tries to connect to a parent that doesn't yet exist, resulting in this splat: [ 0.000478] kobject: '(null)' ((____ptrval____)): is not initialized, yet kobject_get() is being called. [ 0.002925] [c000000002a0fb30] [c00000000073b0bc] kobject_get+0x8c/0x100 (unreliable) [ 0.003071] [c000000002a0fba0] [c00000000087e464] device_add+0xf4/0xb00 [ 0.003194] [c000000002a0fc80] [c000000000a7f6e4] of_device_add+0x64/0x80 [ 0.003321] [c000000002a0fcb0] [c000000000a800d0] of_platform_device_create_pdata+0xd0/0x1b0 [ 0.003476] [c000000002a0fd00] [c00000000201fa44] pnv_get_random_long_early+0x240/0x2e4 [ 0.003623] [c000000002a0fe20] [c000000002060c38] random_init+0xc0/0x214 This patch fixes the issue by doing the platform device creation inside of machine_subsys_initcall. Fixes: f3eac426657d ("powerpc/powernv: wire up rng during setup_arch") Cc: stable@vger.kernel.org Reported-by: Sachin Sant Signed-off-by: Jason A. Donenfeld Tested-by: Sachin Sant [mpe: Change "of node" to "platform device" in change log] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220630121654.1939181-1-Jason@zx2c4.com --- arch/powerpc/platforms/powernv/rng.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) (limited to 'arch/powerpc/platforms/powernv/rng.c') diff --git a/arch/powerpc/platforms/powernv/rng.c b/arch/powerpc/platforms/powernv/rng.c index 463c78c52cc5..3805ad13b8f3 100644 --- a/arch/powerpc/platforms/powernv/rng.c +++ b/arch/powerpc/platforms/powernv/rng.c @@ -176,12 +176,8 @@ static int __init pnv_get_random_long_early(unsigned long *v) NULL) != pnv_get_random_long_early) return 0; - for_each_compatible_node(dn, NULL, "ibm,power-rng") { - if (rng_create(dn)) - continue; - /* Create devices for hwrng driver */ - of_platform_device_create(dn, NULL, NULL); - } + for_each_compatible_node(dn, NULL, "ibm,power-rng") + rng_create(dn); if (!ppc_md.get_random_seed) return 0; @@ -205,10 +201,18 @@ void __init pnv_rng_init(void) static int __init pnv_rng_late_init(void) { + struct device_node *dn; 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); + + if (ppc_md.get_random_seed == powernv_get_random_long) { + for_each_compatible_node(dn, NULL, "ibm,power-rng") + of_platform_device_create(dn, NULL, NULL); + } + return 0; } machine_subsys_initcall(powernv, pnv_rng_late_init); -- cgit v1.2.3-59-g8ed1b