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 X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 023AAC433E3 for ; Tue, 28 Jul 2020 13:46:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D666520663 for ; Tue, 28 Jul 2020 13:46:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ellerman.id.au header.i=@ellerman.id.au header.b="SneZ7VsG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730208AbgG1NqV (ORCPT ); Tue, 28 Jul 2020 09:46:21 -0400 Received: from ozlabs.org ([203.11.71.1]:49183 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730142AbgG1NqT (ORCPT ); Tue, 28 Jul 2020 09:46:19 -0400 Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4BGHyK044Dz9sRK; Tue, 28 Jul 2020 23:46:16 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ellerman.id.au; s=201909; t=1595943977; bh=3y2tXBtxH9v1JkU8HT+t2K5rruo9PDsqNSeSePCEevY=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=SneZ7VsGkX6I5SYitiDPjdb/NKRSzJte8DNHWSKuV0p5f/vnKMX8dFfvbWVtVBQyY MPY4Z/WkYtRQsm8Jdq3ANnNSNrQPrxPneKZ7AcxF3YLUGzVcDPCsPW4uXSBsGX0ZMQ nqIUkH3pultd1Fml9MIsYCYTOLu8CYVZdobYH/XOpHKHnYLex2Eptc+MONqlBTEzn0 LA+aLPgWJ4mdQYOWSeh9UAv2HfXz73P2J68n5Omf796X3FvVKN9QQv95/E1wfR0gAh q3sfuqAcmEBp82lI37FWBvu0yVlK9p3r2x5NLZvxSQQ243btSFSu8hSqRWciV8ZMGf gJCdITLviKJNg== From: Michael Ellerman To: Hari Bathini , Andrew Morton Cc: Mahesh J Salgaonkar , Sourabh Jain , Vivek Goyal , Dave Young , Petr Tesarik , Pingfan Liu , linuxppc-dev , Kexec-ml , lkml , Pingfan Liu , Eric Biederman , Thiago Jung Bauermann , Mimi Zohar , Nayna Jain Subject: Re: [RESEND PATCH v5 07/11] ppc64/kexec_file: enable early kernel's OPAL calls In-Reply-To: <159579233676.5790.10701756666641782647.stgit@hbathini> References: <159579157320.5790.6748078824637688685.stgit@hbathini> <159579233676.5790.10701756666641782647.stgit@hbathini> Date: Tue, 28 Jul 2020 23:46:15 +1000 Message-ID: <87365b7nx4.fsf@mpe.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hari Bathini writes: > Kernel built with CONFIG_PPC_EARLY_DEBUG_OPAL enabled expects r8 & r9 > to be filled with OPAL base & entry addresses respectively. Setting > these registers allows the kernel to perform OPAL calls before the > device tree is parsed. I'm not convinced we want to do this. If we do it becomes part of the kexec ABI and we have to honour it into the future. And in practice there are no non-development kernels built with OPAL early debugging enabled, so it's not clear it actually helps anyone other than developers. cheers > v4 -> v5: > * New patch. Updated opal_base & opal_entry values in r8 & r9 respectively. > This change was part of the below dropped patch in v4: > - https://lore.kernel.org/patchwork/patch/1275667/ > > > arch/powerpc/kexec/file_load_64.c | 16 ++++++++++++++++ > arch/powerpc/purgatory/trampoline_64.S | 15 +++++++++++++++ > 2 files changed, 31 insertions(+) > > diff --git a/arch/powerpc/kexec/file_load_64.c b/arch/powerpc/kexec/file_load_64.c > index 8df085a22fd7..a5c1442590b2 100644 > --- a/arch/powerpc/kexec/file_load_64.c > +++ b/arch/powerpc/kexec/file_load_64.c > @@ -713,6 +713,8 @@ int setup_purgatory_ppc64(struct kimage *image, const void *slave_code, > const void *fdt, unsigned long kernel_load_addr, > unsigned long fdt_load_addr) > { > + struct device_node *dn = NULL; > + uint64_t val; > int ret; > > ret = setup_purgatory(image, slave_code, fdt, kernel_load_addr, > @@ -735,9 +737,23 @@ int setup_purgatory_ppc64(struct kimage *image, const void *slave_code, > goto out; > } > > + /* Setup OPAL base & entry values */ > + dn = of_find_node_by_path("/ibm,opal"); > + if (dn) { > + of_property_read_u64(dn, "opal-base-address", &val); > + ret = kexec_purgatory_get_set_symbol(image, "opal_base", &val, > + sizeof(val), false); > + if (ret) > + goto out; > + > + of_property_read_u64(dn, "opal-entry-address", &val); > + ret = kexec_purgatory_get_set_symbol(image, "opal_entry", &val, > + sizeof(val), false); > + } > out: > if (ret) > pr_err("Failed to setup purgatory symbols"); > + of_node_put(dn); > return ret; > } > > diff --git a/arch/powerpc/purgatory/trampoline_64.S b/arch/powerpc/purgatory/trampoline_64.S > index a5a83c3f53e6..464af8e8a4cb 100644 > --- a/arch/powerpc/purgatory/trampoline_64.S > +++ b/arch/powerpc/purgatory/trampoline_64.S > @@ -61,6 +61,10 @@ master: > li %r4,28 > STWX_BE %r17,%r3,%r4 /* Store my cpu as __be32 at byte 28 */ > 1: > + /* Load opal base and entry values in r8 & r9 respectively */ > + ld %r8,(opal_base - 0b)(%r18) > + ld %r9,(opal_entry - 0b)(%r18) > + > /* load the kernel address */ > ld %r4,(kernel - 0b)(%r18) > > @@ -102,6 +106,17 @@ dt_offset: > .8byte 0x0 > .size dt_offset, . - dt_offset > > + .balign 8 > + .globl opal_base > +opal_base: > + .8byte 0x0 > + .size opal_base, . - opal_base > + > + .balign 8 > + .globl opal_entry > +opal_entry: > + .8byte 0x0 > + .size opal_entry, . - opal_entry > > .data > .balign 8