From mboxrd@z Thu Jan 1 00:00:00 1970 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 741B1C433EF for ; Tue, 5 Jul 2022 12:00:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232871AbiGEMAp (ORCPT ); Tue, 5 Jul 2022 08:00:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42662 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232868AbiGEMAU (ORCPT ); Tue, 5 Jul 2022 08:00:20 -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 A47F817E3C; Tue, 5 Jul 2022 05:00:12 -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 4475A6174B; Tue, 5 Jul 2022 12:00:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 515A6C341C7; Tue, 5 Jul 2022 12:00:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1657022411; bh=n/mTbhU8QDjkSe4pvnDYG+KfiE9r0l3gwSQizEQnMv8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ekbDXyYSMTaUGX2BGYSUuQ4+xNCjZBQhdMSeX4ee7+H0OX7ydZXxxPoShjcFvScOe 9zVfIAXgt1GxwL1usYs4PS8Et4o7Z14xHG8cZVn1eJ3FpaDOKWM/wqzhLq9P15GW2C RiOvAJyI1jGtWxQFWrq5ZQxkghGtOArG+L/DDBQc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Jason A. Donenfeld" , Christophe Leroy , Michael Ellerman Subject: [PATCH 4.9 07/29] powerpc/powernv: wire up rng during setup_arch Date: Tue, 5 Jul 2022 13:57:48 +0200 Message-Id: <20220705115605.962876047@linuxfoundation.org> X-Mailer: git-send-email 2.37.0 In-Reply-To: <20220705115605.742248854@linuxfoundation.org> References: <20220705115605.742248854@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jason A. Donenfeld 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 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 Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/include/asm/ppc-opcode.h | 4 + arch/powerpc/platforms/powernv/powernv.h | 2 arch/powerpc/platforms/powernv/rng.c | 91 ++++++++++++++++++++++++++----- arch/powerpc/platforms/powernv/setup.c | 2 4 files changed, 85 insertions(+), 14 deletions(-) --- a/arch/powerpc/include/asm/ppc-opcode.h +++ b/arch/powerpc/include/asm/ppc-opcode.h @@ -134,6 +134,7 @@ #define PPC_INST_COPY 0x7c00060c #define PPC_INST_COPY_FIRST 0x7c20060c #define PPC_INST_CP_ABORT 0x7c00068c +#define PPC_INST_DARN 0x7c0005e6 #define PPC_INST_DCBA 0x7c0005ec #define PPC_INST_DCBA_MASK 0xfc0007fe #define PPC_INST_DCBAL 0x7c2005ec @@ -328,6 +329,9 @@ /* Deal with instructions that older assemblers aren't aware of */ #define PPC_CP_ABORT stringify_in_c(.long PPC_INST_CP_ABORT) +#define PPC_DARN(t, l) stringify_in_c(.long PPC_INST_DARN | \ + ___PPC_RT(t) | \ + (((l) & 0x3) << 16)) #define PPC_DCBAL(a, b) stringify_in_c(.long PPC_INST_DCBAL | \ __PPC_RA(a) | __PPC_RB(b)) #define PPC_DCBZL(a, b) stringify_in_c(.long PPC_INST_DCBZL | \ --- a/arch/powerpc/platforms/powernv/powernv.h +++ b/arch/powerpc/platforms/powernv/powernv.h @@ -27,4 +27,6 @@ extern void opal_event_shutdown(void); bool cpu_core_split_required(void); +void pnv_rng_init(void); + #endif /* _POWERNV_H */ --- a/arch/powerpc/platforms/powernv/rng.c +++ b/arch/powerpc/platforms/powernv/rng.c @@ -16,11 +16,14 @@ #include #include #include +#include #include #include #include #include +#include "powernv.h" +#define DARN_ERR 0xFFFFFFFFFFFFFFFFul struct powernv_rng { void __iomem *regs; @@ -30,7 +33,6 @@ struct powernv_rng { static DEFINE_PER_CPU(struct powernv_rng *, powernv_rng); - int powernv_hwrng_present(void) { struct powernv_rng *rng; @@ -45,7 +47,11 @@ static unsigned long rng_whiten(struct p unsigned long parity; /* Calculate the parity of the value */ - asm ("popcntd %0,%1" : "=r" (parity) : "r" (val)); + asm (".machine push; \ + .machine power7; \ + popcntd %0,%1; \ + .machine pop;" + : "=r" (parity) : "r" (val)); /* xor our value with the previous mask */ val ^= rng->mask; @@ -67,6 +73,38 @@ int powernv_get_random_real_mode(unsigne return 1; } +static int powernv_get_random_darn(unsigned long *v) +{ + unsigned long val; + + /* Using DARN with L=1 - 64-bit conditioned random number */ + asm volatile(PPC_DARN(%0, 1) : "=r"(val)); + + if (val == DARN_ERR) + return 0; + + *v = val; + + return 1; +} + +static int __init initialise_darn(void) +{ + unsigned long val; + int i; + + if (!cpu_has_feature(CPU_FTR_ARCH_300)) + return -ENODEV; + + for (i = 0; i < 10; i++) { + if (powernv_get_random_darn(&val)) { + ppc_md.get_random_seed = powernv_get_random_darn; + return 0; + } + } + return -EIO; +} + int powernv_get_random_long(unsigned long *v) { struct powernv_rng *rng; @@ -88,7 +126,7 @@ static __init void rng_init_per_cpu(stru chip_id = of_get_ibm_chip_id(dn); if (chip_id == -1) - pr_warn("No ibm,chip-id found for %s.\n", dn->full_name); + pr_warn("No ibm,chip-id found for %pOF.\n", dn); for_each_possible_cpu(cpu) { if (per_cpu(powernv_rng, cpu) == NULL || @@ -126,30 +164,55 @@ 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 %s (%d).\n", - dn->full_name, rc); + if (rng_create(dn)) continue; - } - /* Create devices for hwrng driver */ of_platform_device_create(dn, NULL, NULL); } + 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 @@ -168,6 +168,8 @@ static void __init pnv_setup_arch(void) powersave_nap = 1; /* XXX PMCS */ + + pnv_rng_init(); } static void __init pnv_init(void)