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From:   Rob Herring <robh@kernel.org>
Date:   Thu, 17 Dec 2020 16:01:28 -0600
Message-ID: <CAL_Jsq+-HOkxtxOO=zyRbDuGVNZoMy589qoVANciNionsdsGCw@mail.gmail.com>
Subject: Re: [PATCH v12 2/4] powerpc: Move arch independent ima kexec
 functions to drivers/of/kexec.c
To:     Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Cc:     Mimi Zohar <zohar@linux.ibm.com>,
        Thiago Jung Bauermann <bauerman@linux.ibm.com>,
        "AKASHI, Takahiro" <takahiro.akashi@linaro.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Will Deacon <will@kernel.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        James Morse <james.morse@arm.com>,
        Sasha Levin <sashal@kernel.org>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Frank Rowand <frowand.list@gmail.com>,
        vincenzo.frascino@arm.com, Mark Rutland <mark.rutland@arm.com>,
        dmitry.kasatkin@gmail.com, James Morris <jmorris@namei.org>,
        "Serge E. Hallyn" <serge@hallyn.com>,
        Pavel Tatashin <pasha.tatashin@soleen.com>,
        Allison Randal <allison@lohutok.net>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Bhupesh Sharma <bhsharma@redhat.com>,
        Matthias Brugger <mbrugger@suse.com>,
        Hsin-Yi Wang <hsinyi@chromium.org>, tao.li@vivo.com,
        Christophe Leroy <christophe.leroy@c-s.fr>,
        Prakhar Srivastava <prsriva@linux.microsoft.com>,
        balajib@linux.microsoft.com, linux-integrity@vger.kernel.org,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        devicetree@vger.kernel.org
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On Thu, Dec 17, 2020 at 2:52 PM Lakshmi Ramasubramanian
<nramas@linux.microsoft.com> wrote:
>
> On 12/17/20 12:05 PM, Rob Herring wrote:
> > On Thu, Dec 17, 2020 at 09:37:06AM -0800, Lakshmi Ramasubramanian wrote:
> >> The functions defined in "arch/powerpc/kexec/ima.c" handle setting up
> >> and freeing the resources required to carry over the IMA measurement
> >> list from the current kernel to the next kernel across kexec system call.
> >> These functions do not have architecture specific code, but are
> >> currently limited to powerpc.

[...]

> >> +#ifdef CONFIG_IMA_KEXEC
> >> +/**
> >> + * arch_ima_add_kexec_buffer - do arch-specific steps to add the IMA buffer
> >> + *
> >> + * @image: kimage struct to set IMA buffer data
> >> + * @load_addr: Starting address where IMA buffer is loaded at
> >> + * @size: Number of bytes in the IMA buffer
> >> + *
> >> + * Architectures should use this function to pass on the IMA buffer
> >> + * information to the next kernel.
> >> + *
> >> + * Return: 0 on success, negative errno on error.
> >> + */
> >> +int arch_ima_add_kexec_buffer(struct kimage *image, unsigned long load_addr,
> >> +                          size_t size)
> >
> > This should be a static inline in asm/kexec.h.
>
> arch_ima_add_kexec_buffer() is identical for powerpc and arm64.
> Would it be better to "static inline" this function in "of.h" instead of
> duplicating it in "asm/kexec.h" for powerpc and arm64?

No, think about what it is specific to and place it there. It has
nothing to do with DT really. All it is is a wrapper to access the
struct members in kimage_arch. So it belongs where they are declared.
Now perhaps ima_buffer_addr and ima_buffer_size shouldn't be arch
specific, but that's a separate issue.

Rob