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From:   Sven Schnelle <svens@linux.ibm.com>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Thomas Richter <tmricht@linux.ibm.com>,
        linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org,
        Thomas Gleixner <tglx@linutronix.de>,
        Andy Lutomirski <luto@kernel.org>
Subject: Re: [PATCH 1/2] entry: Rename arch_check_user_regs() to
 arch_enter_from_user_mode()
References: <20220504062351.2954280-1-tmricht@linux.ibm.com>
        <20220504062351.2954280-2-tmricht@linux.ibm.com>
        <YnV3iljKUM0Fqw/F@hirez.programming.kicks-ass.net>
Date:   Mon, 09 May 2022 08:20:41 +0200
In-Reply-To: <YnV3iljKUM0Fqw/F@hirez.programming.kicks-ass.net> (Peter
        Zijlstra's message of "Fri, 6 May 2022 21:31:22 +0200")
Message-ID: <yt9dsfpjgrba.fsf@linux.ibm.com>
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Peter Zijlstra <peterz@infradead.org> writes:

> On Wed, May 04, 2022 at 08:23:50AM +0200, Thomas Richter wrote:
>> From: Sven Schnelle <svens@linux.ibm.com>
>> 
>> arch_check_user_regs() is used at the moment to verify that struct pt_regs
>> contains valid values when entering the kernel from userspace. s390 needs
>> a place in the generic entry code to modify a cpu data structure when
>> switching from userspace to kernel mode. As arch_check_user_regs() is
>> exactly this, rename it to arch_enter_from_user_mode().
>> 
>> Cc: Thomas Gleixner <tglx@linutronix.de>
>> Cc: Peter Zijlstra <peterz@infradead.org>
>> Cc: Andy Lutomirski <luto@kernel.org>
>> Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
>> ---
>
> With the note that NMI doesn't (necessarily) call this..
>
> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

How about:

"When entering the kernel from userspace, arch_check_user_regs() is
 used to verify that struct pt_regs contains valid values. Note that
 the NMI codepath doesn't call this function. s390 needs a place in the
 generic entry code to modify a cpu data structure when switching from
 userspace to kernel mode. As arch_check_user_regs() is exactly this,
 rename it to arch_enter_from_user_mode()."