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Date:   Thu, 23 Nov 2023 22:31:59 +0800
From:   Baoquan He <bhe@redhat.com>
To:     Alexander Gordeev <agordeev@linux.ibm.com>
Cc:     linux-kernel@vger.kernel.org, kexec@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org,
        akpm@linux-foundation.org, ignat@cloudflare.com,
        eric_devolder@yahoo.com
Subject: Re: [PATCH 3/3] s390/Kconfig: drop select of KEXEC
Message-ID: <ZV9iX5HNftPjNr3S@MiWiFi-R3L-srv>
References: <20231123073652.507034-1-bhe@redhat.com>
 <20231123073652.507034-4-bhe@redhat.com>
 <ZV9W5AmmYhCFmN9e@li-008a6a4c-3549-11b2-a85c-c5cc2836eea2.ibm.com>
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On 11/23/23 at 02:43pm, Alexander Gordeev wrote:
> On Thu, Nov 23, 2023 at 03:36:52PM +0800, Baoquan He wrote:
> 
> Hi Baoquan,
> 
> > No proof is found to require that S390 architecture has to select
> > KEXEC. At least from my testing at below, dropping select of KEXEC won't
> > impact anything.
> 
> It does impact the outcome of defconfigs.
> Namely, CONFIG_KEXEC is not set with this patch.

Right, CONFIG_KEXEC won't be set defaultly with this patch applied.

> 
> > ===testing 1===
> > CONFIG_CRASH_CORE=y
> > CONFIG_KEXEC_CORE=y
> > CONFIG_CRASH_DUMP=y
> > ===
> > 
> > ===testing 2===
> > CONFIG_CRASH_CORE=y
> > CONFIG_KEXEC_CORE=y
> > CONFIG_KEXEC_FILE=y
> > CONFIG_CRASH_DUMP=y
> > ===
> 
> Unfortunately, I do not quite realize what these testings were
> and what is the difference between the two.

Both these two testings have CONFIG_KEXEC=n, and building all passed.
I wound't present their difference, but two cases where no CONFIG_KEXEC
is set and no dependency on CONFIG_KEXEC is seen.

> 
> > So drop the select of KEXEC now.
> 
> I suggest dropping this patch. Once the previous two are upstream
> we would remove 'select KEXEC' from Kconfig together with defconfig
> updates.

I see your concern, will drop this one in v2. Thanks for checking these.

> 
> > Signed-off-by: Baoquan He <bhe@redhat.com>
> > ---
> >  arch/s390/Kconfig | 1 -
> >  1 file changed, 1 deletion(-)
> > 
> > diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
> > index 3bec98d20283..1aec2e692dca 100644
> > --- a/arch/s390/Kconfig
> > +++ b/arch/s390/Kconfig
> > @@ -217,7 +217,6 @@ config S390
> >  	select HAVE_VIRT_CPU_ACCOUNTING_IDLE
> >  	select IOMMU_HELPER		if PCI
> >  	select IOMMU_SUPPORT		if PCI
> > -	select KEXEC
> >  	select MMU_GATHER_MERGE_VMAS
> >  	select MMU_GATHER_NO_GATHER
> >  	select MMU_GATHER_RCU_TABLE_FREE
> > -- 
> 
> Thanks!
>