Subject: Re: spinlock.c:306:9: error: implicit declaration of function
 '__raw_write_lock_nested'
To:     Arnd Bergmann <arnd@arndb.de>,
        Naresh Kamboju <naresh.kamboju@linaro.org>
Cc:     Linux-Next Mailing List <linux-next@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>,
        Linux-sh list <linux-sh@vger.kernel.org>,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
        Waiman Long <longman@redhat.com>,
        Boqun Feng <boqun.feng@gmail.com>,
        Minchan Kim <minchan@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Mike Galbraith <umgwanakikbuti@gmail.com>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        Sergey Senozhatsky <senozhatsky@chromium.org>,
        Yoshinori Sato <ysato@users.sourceforge.jp>,
        Rich Felker <dalias@libc.org>, lkft-triage@lists.linaro.org
References: <CA+G9fYtH2JR=L0cPoOEqsEGrZW_uOJgX6qLGMe_hbLpBtjVBwA@mail.gmail.com>
 <CAK8P3a1NhpNxWfj3gDnuf4bWK_fiE8cjcRyN7e8j95NmvOzbGw@mail.gmail.com>
From:   Rob Landley <rob@landley.net>
Message-ID: <8767803d-57b9-698c-ca27-d47e7117758d@landley.net>
Date:   Wed, 24 Nov 2021 04:01:05 -0600
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On 11/23/21 7:19 AM, Arnd Bergmann wrote:
> On Tue, Nov 23, 2021 at 12:38 PM Naresh Kamboju
> <naresh.kamboju@linaro.org> wrote:
>>
>> While building Linux next 20211123 tag for sh with gcc-11
>> following warnings / errors noticed.
> 
> Nothing in here looks like a recent regression from either the kernel
> or gcc-11.
> 
>> make --silent --keep-going --jobs=8
>> O=/home/tuxbuild/.cache/tuxmake/builds/current ARCH=sh
>> CROSS_COMPILE=sh4-linux-gnu- 'CC=sccache sh4-linux-gnu-gcc'
>> 'HOSTCC=sccache gcc'
>>   Generating include/generated/machtypes.h
>> <stdin>:1517:2: warning: #warning syscall clone3 not implemented [-Wcpp]
>> <stdin>:1559:2: warning: #warning syscall futex_waitv not implemented [-Wcpp]
> 
> These happen with any compiler version, someone needs to write the correct
> entry code for clone3 and hook up futex_waitv().

I did a naieve "add them both to the .tbl" patch and the result booted to a
shell prompt, but that doesn't mean much. What arch-specific entry code does
clone3 need here? The SYSCALL_DEFINE2(clone3) in kernel/fork.c seems reasonably
straightforward? (Unlike the #ifdef stack around the previous clone...)

>> include/linux/sh_intc.h:100:63: warning: division 'sizeof (void *) / sizeof (void)' does not compute the number of array elements
> 
> These are old bugs, they show up in any kernel version with gcc-8 or higher.

I looked at trying to fix that but it seems to be a compiler bug. Gcc is warning
about an ? : else case that's dead code eliminated. It's already GOT a test
protecting it from being evaluated...

>> fs/mpage.c:336:1: warning: the frame size of 1092 bytes is larger than
> 
> I see these going back to gcc-6, it looks like this is caused by
> CONFIG_PAGE_SIZE_64KB.

In which case the stack size is going to be 64k as well?

>      Arnd

Rob