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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id CE3C3C54E49 for ; Thu, 7 Mar 2024 10:42:14 +0000 (UTC) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=ellerman.id.au header.i=@ellerman.id.au header.a=rsa-sha256 header.s=201909 header.b=SSkWN/Cs; dkim-atps=neutral Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Tr5Td3Zghz3dlT for ; Thu, 7 Mar 2024 21:42:13 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=ellerman.id.au header.i=@ellerman.id.au header.a=rsa-sha256 header.s=201909 header.b=SSkWN/Cs; dkim-atps=neutral Received: from gandalf.ozlabs.org (mail.ozlabs.org [IPv6:2404:9400:2221:ea00::3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4Tr5Sr2gZ9z3cJW for ; Thu, 7 Mar 2024 21:41:32 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ellerman.id.au; s=201909; t=1709808092; bh=QHwyFDcupjhTArKQOMkjJ6sLtDVOUhAmTuA0clhv4wM=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=SSkWN/CsUdTccQiVHbYQloY9qgzNHOhp2tWHvvoiKfSTW/OXDLdNJfX0VnHwmCfk3 gtXjChFioqzzrlQZsgsma3C+QfV75e2zWgTRiuV2A33jW2W9DJDl2k/5DCfHf2s97R CtqUlxkXS5agv/jFDIXkpHkq/5X5/uPmaG5wSA+MM2l+xj1lu3ST142FhSKunOHswc cJ3cFlZHsZFtw5Xrvnba1Eo55c7kG6lwjb+21AQgqP1izxedl6YQ+k81o8+Q6TPQcv T05V3+iI3v1B70IsNm853jwb7VnOmpgMkd7Gh0fj5PxJ8JyKFdoSxGZAbRd7SS75ad c6F7yI7FwY3IA== 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 X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4Tr5Sr1LbWz4wc5; Thu, 7 Mar 2024 21:41:32 +1100 (AEDT) From: Michael Ellerman To: Stefan Berger , linux-integrity@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH 1/2] powerpc/prom_init: Replace linux,sml-base/sml-size with linux,sml-log In-Reply-To: <20240306155511.974517-2-stefanb@linux.ibm.com> References: <20240306155511.974517-1-stefanb@linux.ibm.com> <20240306155511.974517-2-stefanb@linux.ibm.com> Date: Thu, 07 Mar 2024 21:41:31 +1100 Message-ID: <87jzmenx2c.fsf@mail.lhotse> MIME-Version: 1.0 Content-Type: text/plain X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: rnsastry@linux.ibm.com, linux-kernel@vger.kernel.org, jarkko@kernel.org, peterhuewe@gmx.de, viparash@in.ibm.com, Stefan Berger Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Stefan Berger writes: > linux,sml-base holds the address of a buffer with the TPM log. This > buffer may become invalid after a kexec and therefore embed the whole TPM > log in linux,sml-log. This helps to protect the log since it is properly > carried across a kexec with both of the kexec syscalls. > > Signed-off-by: Stefan Berger > --- > arch/powerpc/kernel/prom_init.c | 8 ++------ > 1 file changed, 2 insertions(+), 6 deletions(-) > > diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c > index e67effdba85c..41268c30de4c 100644 > --- a/arch/powerpc/kernel/prom_init.c > +++ b/arch/powerpc/kernel/prom_init.c > @@ -1956,12 +1956,8 @@ static void __init prom_instantiate_sml(void) > > reserve_mem(base, size); > > - prom_setprop(ibmvtpm_node, "/vdevice/vtpm", "linux,sml-base", > - &base, sizeof(base)); > - prom_setprop(ibmvtpm_node, "/vdevice/vtpm", "linux,sml-size", > - &size, sizeof(size)); > - > - prom_debug("sml base = 0x%llx\n", base); > + prom_setprop(ibmvtpm_node, "/vdevice/vtpm", "linux,sml-log", > + (void *)base, size); As we discussed via chat, doing it this way sucks the full content of the log back into Open Firmware. That relies on OF handling such big properties, and also means more memory will be consumed, which can cause problems early in boot. A better solution is to explicitly add the log to the FDT in the flattening phase. Also adding the new linux,sml-log property should be accompanied by a change to the device tree binding. The syntax is not very obvious to me, but possibly something like? diff --git a/Documentation/devicetree/bindings/tpm/ibm,vtpm.yaml b/Documentation/devicetree/bindings/tpm/ibm,vtpm.yaml index 50a3fd31241c..cd75037948bc 100644 --- a/Documentation/devicetree/bindings/tpm/ibm,vtpm.yaml +++ b/Documentation/devicetree/bindings/tpm/ibm,vtpm.yaml @@ -74,8 +74,6 @@ required: - ibm,my-dma-window - ibm,my-drc-index - ibm,loc-code - - linux,sml-base - - linux,sml-size allOf: - $ref: tpm-common.yaml# diff --git a/Documentation/devicetree/bindings/tpm/tpm-common.yaml b/Documentation/devicetree/bindings/tpm/tpm-common.yaml index 3c1241b2a43f..616604707c95 100644 --- a/Documentation/devicetree/bindings/tpm/tpm-common.yaml +++ b/Documentation/devicetree/bindings/tpm/tpm-common.yaml @@ -25,6 +25,11 @@ properties: base address of reserved memory allocated for firmware event log $ref: /schemas/types.yaml#/definitions/uint64 + linux,sml-log: + description: + Content of firmware event log + $ref: /schemas/types.yaml#/definitions/uint8-array + linux,sml-size: description: size of reserved memory allocated for firmware event log @@ -53,15 +58,22 @@ dependentRequired: linux,sml-base: ['linux,sml-size'] linux,sml-size: ['linux,sml-base'] -# must only have either memory-region or linux,sml-base +# must only have either memory-region or linux,sml-base/size or linux,sml-log # as well as either resets or reset-gpios dependentSchemas: memory-region: properties: linux,sml-base: false + linux,sml-log: false linux,sml-base: properties: memory-region: false + linux,sml-log: false + linux,sml-log: + properties: + memory-region: false + linux,sml-base: false + linux,sml-size: false resets: properties: reset-gpios: false cheers