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Date: Thu, 07 Mar 2024 22:11:21 +0200
Message-Id: <CZNSI4DXQMH4.2IYN7ZDJEBG59@kernel.org>
To: "Stefan Berger" <stefanb@linux.ibm.com>, <mpe@ellerman.id.au>,
 <linux-integrity@vger.kernel.org>, <linuxppc-dev@lists.ozlabs.org>
Cc: <linux-kernel@vger.kernel.org>, <rnsastry@linux.ibm.com>,
 <peterhuewe@gmx.de>, <viparash@in.ibm.com>
Subject: Re: [PATCH 1/2] powerpc/prom_init: Replace linux,sml-base/sml-size
 with linux,sml-log
From: "Jarkko Sakkinen" <jarkko@kernel.org>
References: <20240306155511.974517-1-stefanb@linux.ibm.com>
 <20240306155511.974517-2-stefanb@linux.ibm.com>
In-Reply-To: <20240306155511.974517-2-stefanb@linux.ibm.com>

On Wed Mar 6, 2024 at 5:55 PM EET, Stefan Berger wrote:
> 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.

So, I see only description of the problem but nothing how it gets
addressed.

>
> Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
> ---
>  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_i=
nit.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)
> =20
>  	reserve_mem(base, size);
> =20
> -	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     =3D 0x%llx\n", base);
> +	prom_setprop(ibmvtpm_node, "/vdevice/vtpm", "linux,sml-log",
> +		     (void *)base, size);
>  	prom_debug("sml size     =3D 0x%x\n", size);
> =20
>  	prom_debug("prom_instantiate_sml: end...\n");

BR, Jarkko