Lakshmi Ramasubramanian <nramas@xxxxxxxxxxxxxxxxxxx> writes:
> On 2/18/21 5:13 PM, Thiago Jung Bauermann wrote:
>> Lakshmi Ramasubramanian <nramas@xxxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxxx>
>>>>> Fixes: 33488dc4d61f ("of: Add a common kexec FDT setup function")
>>>>> Reported-by: kernel test robot <lkp@xxxxxxxxx>
>>>>> ---
>>>>> 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"?
Ah, right. I should have digged into the code before making my
suggestion. CONFIG_HAVE_KIMAGE_ARCH isn't appropriate, indeed.
>
> Rob/Mimi - please let us know which approach you think is better.
Ah! We can actually use the existing CONFIG_HAVE_IMA_KEXEC, no? I don't
know why I didn't think of it before.
--
Thiago Jung Bauermann
IBM Linux Technology Center
