From nobody Sun Apr 26 23:10:04 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C1E89C433EF for ; Tue, 21 Jun 2022 14:09:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350770AbiFUOI6 (ORCPT ); Tue, 21 Jun 2022 10:08:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55604 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350568AbiFUOI5 (ORCPT ); Tue, 21 Jun 2022 10:08:57 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C0EBC20BD8; Tue, 21 Jun 2022 07:08:56 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 5D10D61637; Tue, 21 Jun 2022 14:08:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0367CC3411C; Tue, 21 Jun 2022 14:08:54 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="ZIfwWxWI" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1655820532; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=o1gYjl7KPX16iqAFGXtFcntDw+PS97kgCGFtyPRPPLo=; b=ZIfwWxWIQEmwVtW3nHnpJPrV1JhXCM3H6T73nFa9Orxl03gLbNcGwTgZWNqMIB04R74HTB MmHpVWV8jgq/gPd5e90TsQjjA9r6dyshfYdN2QRp+mbEx10dklm9rUW8mN3MxIFmX+JusS UzTV6slWEX/oURVmprW5R+kfjcANeiE= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 528b99a0 (TLSv1.3:AEAD-AES256-GCM-SHA384:256:NO); Tue, 21 Jun 2022 14:08:52 +0000 (UTC) From: "Jason A. Donenfeld" To: Michael Ellerman , linuxppc-dev@lists.ozlabs.org, LKML , stable , Christophe Leroy Cc: "Jason A. Donenfeld" Subject: [PATCH v5] powerpc/powernv: wire up rng during setup_arch Date: Tue, 21 Jun 2022 16:08:49 +0200 Message-Id: <20220621140849.127227-1-Jason@zx2c4.com> In-Reply-To: <20220620124531.78075-1-Jason@zx2c4.com> References: <20220620124531.78075-1-Jason@zx2c4.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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 we can wire it up that way. 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. Cc: stable@vger.kernel.org Cc: Michael Ellerman Reviewed-by: Christophe Leroy Fixes: a4da0d50b2a0 ("powerpc: Implement arch_get_random_long/int() for pow= ernv") Signed-off-by: Jason A. Donenfeld --- arch/powerpc/platforms/powernv/powernv.h | 2 + arch/powerpc/platforms/powernv/rng.c | 47 ++++++++++++++++-------- arch/powerpc/platforms/powernv/setup.c | 2 + 3 files changed, 35 insertions(+), 16 deletions(-) diff --git a/arch/powerpc/platforms/powernv/powernv.h b/arch/powerpc/platfo= rms/powernv/powernv.h index e297bf4abfcb..fd3f5e1eb10b 100644 --- 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, 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); =20 +void powernv_rng_init(void); + #endif /* _POWERNV_H */ diff --git a/arch/powerpc/platforms/powernv/rng.c b/arch/powerpc/platforms/= powernv/rng.c index e3d44b36ae98..e332e72e1857 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" =20 #define DARN_ERR 0xFFFFFFFFFFFFFFFFul =20 @@ -28,7 +29,6 @@ struct powernv_rng { =20 static DEFINE_PER_CPU(struct powernv_rng *, powernv_rng); =20 - 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; } =20 @@ -163,32 +160,50 @@ static __init int rng_create(struct device_node *dn) =20 rng_init_per_cpu(rng, dn); =20 - pr_info_once("Registering arch random hook.\n"); - ppc_md.get_random_seed =3D powernv_get_random_long; =20 return 0; } =20 -static __init int rng_init(void) +static int __init powernv_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, powernv_get_random_long_early, + NULL) !=3D powernv_get_random_long_early) + return 0; =20 for_each_compatible_node(dn, NULL, "ibm,power-rng") { - rc =3D 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); } =20 - initialise_darn(); + if (!ppc_md.get_random_seed) + return 0; + return ppc_md.get_random_seed(v); +} + +void __init powernv_rng_init(void) +{ + /* Prefer darn over the rest. */ + if (!initialise_darn()) + return; + + if (of_find_compatible_node(NULL, NULL, "ibm,power-rng")) + ppc_md.get_random_seed =3D powernv_get_random_long_early; +} =20 +static int __init powernv_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 =3D=3D powernv_get_random_long_early) + powernv_get_random_long_early(&v); return 0; } -machine_subsys_initcall(powernv, rng_init); +machine_subsys_initcall(powernv, powernv_rng_late_init); diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platform= s/powernv/setup.c index 824c3ad7a0fa..a5fcb6796b22 100644 --- a/arch/powerpc/platforms/powernv/setup.c +++ b/arch/powerpc/platforms/powernv/setup.c @@ -203,6 +203,8 @@ static void __init pnv_setup_arch(void) pnv_check_guarded_cores(); =20 /* XXX PMCS */ + + powernv_rng_init(); } =20 static void __init pnv_init(void) --=20 2.35.1