Date:   Fri, 19 Feb 2021 08:56:58 -0800
From:   Lakshmi Ramasubramanian <nramas@...ux.microsoft.com>
To:     Rob Herring <robh@...nel.org>
Cc:     Thiago Jung Bauermann <bauerman@...ux.ibm.com>,
        Mimi Zohar <zohar@...ux.ibm.com>,
        "AKASHI, Takahiro" <takahiro.akashi@...aro.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Will Deacon <will@...nel.org>, Joe Perches <joe@...ches.com>,
        Catalin Marinas <catalin.marinas@....com>,
        Michael Ellerman <mpe@...erman.id.au>,
        Stephen Rothwell <sfr@...b.auug.org.au>,
        James Morse <james.morse@....com>,
        Sasha Levin <sashal@...nel.org>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        linux-integrity@...r.kernel.org,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        devicetree@...r.kernel.org,
        linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>
Subject: Re: [PATCH] of: error: 'const struct kimage' has no member named
 'arch'

On 2/19/21 6:16 AM, Rob Herring wrote:
> On Thu, Feb 18, 2021 at 8:53 PM Lakshmi Ramasubramanian
> <nramas@...ux.microsoft.com> wrote:
>>
>> On 2/18/21 5:13 PM, Thiago Jung Bauermann wrote:
>>>
>>> Lakshmi Ramasubramanian <nramas@...ux.microsoft.com> writes:
>>>
>>>> On 2/18/21 4:07 PM, Mimi Zohar wrote:
>>>>
>>>> Hi Mimi,
>>>>
>>>>> On Thu, 2021-02-18 at 14:33 -0800, Lakshmi Ramasubramanian wrote:
>>>>>> of_kexec_alloc_and_setup_fdt() defined in drivers/of/kexec.c builds
>>>>>> a new device tree object that includes architecture specific data
>>>>>> for kexec system call.  This should be defined only if the architecture
>>>>>> being built defines kexec architecture structure "struct kimage_arch".
>>>>>>
>>>>>> Define a new boolean config OF_KEXEC that is enabled if
>>>>>> CONFIG_KEXEC_FILE and CONFIG_OF_FLATTREE are enabled, and
>>>>>> the architecture is arm64 or powerpc64.  Build drivers/of/kexec.c
>>>>>> if CONFIG_OF_KEXEC is enabled.
>>>>>>
>>>>>> Signed-off-by: Lakshmi Ramasubramanian <nramas@...ux.microsoft.com>
>>>>>> Fixes: 33488dc4d61f ("of: Add a common kexec FDT setup function")
>>>>>> Reported-by: kernel test robot <lkp@...el.com>
>>>>>> ---
>>>>>>     drivers/of/Kconfig  | 6 ++++++
>>>>>>     drivers/of/Makefile | 7 +------
>>>>>>     2 files changed, 7 insertions(+), 6 deletions(-)
>>>>>>
>>>>>> diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
>>>>>> index 18450437d5d5..f2e8fa54862a 100644
>>>>>> --- a/drivers/of/Kconfig
>>>>>> +++ b/drivers/of/Kconfig
>>>>>> @@ -100,4 +100,10 @@ config OF_DMA_DEFAULT_COHERENT
>>>>>>             # arches should select this if DMA is coherent by default for OF devices
>>>>>>             bool
>>>>>>     +config OF_KEXEC
>>>>>> +  bool
>>>>>> +  depends on KEXEC_FILE
>>>>>> +  depends on OF_FLATTREE
>>>>>> +  default y if ARM64 || PPC64
>>>>>> +
>>>>>>     endif # OF
>>>>>> diff --git a/drivers/of/Makefile b/drivers/of/Makefile
>>>>>> index c13b982084a3..287579dd1695 100644
>>>>>> --- a/drivers/of/Makefile
>>>>>> +++ b/drivers/of/Makefile
>>>>>> @@ -13,11 +13,6 @@ obj-$(CONFIG_OF_RESERVED_MEM) += of_reserved_mem.o
>>>>>>     obj-$(CONFIG_OF_RESOLVE)  += resolver.o
>>>>>>     obj-$(CONFIG_OF_OVERLAY) += overlay.o
>>>>>>     obj-$(CONFIG_OF_NUMA) += of_numa.o
>>>>>> -
>>>>>> -ifdef CONFIG_KEXEC_FILE
>>>>>> -ifdef CONFIG_OF_FLATTREE
>>>>>> -obj-y     += kexec.o
>>>>>> -endif
>>>>>> -endif
>>>>>> +obj-$(CONFIG_OF_KEXEC) += kexec.o
>>>>>>       obj-$(CONFIG_OF_UNITTEST) += unittest-data/
>>>>> Is it possible to reuse CONFIG_HAVE_IMA_KEXEC here?
>>>>>
>>>>
>>>> For ppc64 CONFIG_HAVE_IMA_KEXEC is selected when CONFIG_KEXEC_FILE is enabled.
>>>> So I don't see a problem in reusing CONFIG_HAVE_IMA_KEXEC for ppc.
>>>>
>>>> But for arm64, CONFIG_HAVE_IMA_KEXEC is enabled in the final patch in the patch
>>>> set (the one for carrying forward IMA log across kexec for arm64). arm64 calls
>>>> of_kexec_alloc_and_setup_fdt() prior to enabling CONFIG_HAVE_IMA_KEXEC and hence
>>>> breaks the build for arm64.
>>>
>>> One problem is that I believe that this patch won't placate the robot,
>>> because IIUC it generates config files at random and this change still
>>> allows hppa and s390 to enable CONFIG_OF_KEXEC.
>>
>> I enabled CONFIG_OF_KEXEC for s390. With my patch applied,
>> CONFIG_OF_KEXEC is removed. So I think the robot enabling this config
>> would not be a problem.
>>
>>>
>>> Perhaps a new CONFIG_HAVE_KIMAGE_ARCH option? Not having that option
>>> would still allow building kexec.o, but would be used inside kexec.c to
>>> avoid accessing kimage.arch members.
>>>
>>
>> I think this is a good idea - a new CONFIG_HAVE_KIMAGE_ARCH, which will
>> be selected by arm64 and ppc for now. I tried this, and it fixes the
>> build issue.
>>
>> Although, the name for the new config can be misleading since PARISC,
>> for instance, also defines "struct kimage_arch". Perhaps,
>> CONFIG_HAVE_ELF_KIMAGE_ARCH since of_kexec_alloc_and_setup_fdt() is
>> accessing ELF specific fields in "struct kimage_arch"?
>>
>> Rob/Mimi - please let us know which approach you think is better.
> 
> I'd just move the fields to kimage.
> 

I think Mimi's suggestion to use CONFIG_HAVE_IMA_KEXEC for building 
drivers/of/kexec.c would work and also avoid the bisect issue if we do 
the following:

  - In the patch set for carrying forward the IMA log on kexec, move the 
following patch to a later point in the set

"[PATCH v18 04/11] arm64: Use common of_kexec_alloc_and_setup_fdt()"

and merge the above patch with the following patch
"[PATCH v18 11/11] arm64: Enable passing IMA log to next kernel on kexec"

I will try this now, and update.

thanks,
  -lakshmi

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