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From:   Sven Schnelle <svens@linux.ibm.com>
To:     Mark Rutland <mark.rutland@arm.com>
Cc:     Andy Lutomirski <luto@kernel.org>, x86@kernel.org,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 08/11] entry: Make CONFIG_DEBUG_ENTRY available
 outside x86
References: <cover.1614884673.git.luto@kernel.org>
        <d5b13da88adf4e732a07fe709263e572cb5ca8de.1614884673.git.luto@kernel.org>
        <20210308101347.GD7951@C02TD0UTHF1T.local>
Date:   Mon, 29 Mar 2021 13:50:52 +0200
In-Reply-To: <20210308101347.GD7951@C02TD0UTHF1T.local> (Mark Rutland's
        message of "Mon, 8 Mar 2021 10:13:47 +0000")
Message-ID: <yt9d7dlqw543.fsf@linux.ibm.com>
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Mark Rutland <mark.rutland@arm.com> writes:

> On Thu, Mar 04, 2021 at 11:06:01AM -0800, Andy Lutomirski wrote:
>> In principle, the generic entry code is generic, and the goal is to use it
>> in many architectures once it settles down more.  Move CONFIG_DEBUG_ENTRY
>> to the generic config so that it can be used in the generic entry code and
>> not just in arch/x86.
>> 
>> Disable it on arm64.  arm64 uses some but not all of the kentry
>> code, and trying to debug the resulting state machine will be painful.
>> arm64 can turn it back on when it starts using the entire generic
>> path.
>
> Can we make this depend on CONFIG_GENERIC_ENTRY instead of !ARM64?
> That'd be more in line with "use the generic entry code, get the generic
> functionality". Note that arm64 doesn't select CONFIG_GENERIC_ENTRY
> today.
>
> I see that s390 selects CONFIG_GENERIC_ENTRY, and either way this will
> enable DEBUG_ENTRY for them, so it'd ve worth checking whether this is
> ok for them.
>
> Sven, thoughts?
>

For s390 that change should be fine.