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Date:   Sat, 10 Dec 2022 10:37:34 +0100
From:   Willy Tarreau <w@1wt.eu>
To:     Sven Schnelle <svens@linux.ibm.com>
Cc:     "Paul E . McKenney" <paulmck@kernel.org>,
        Josh Triplett <josh@joshtriplett.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Lai Jiangshan <jiangshanlai@gmail.com>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/5] nolibc: add support for s390
Message-ID: <20221210093734.GE21743@1wt.eu>
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 <20221210090728.GB21743@1wt.eu>
 <yt9dmt7vtxf3.fsf@linux.ibm.com>
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On Sat, Dec 10, 2022 at 10:34:08AM +0100, Sven Schnelle wrote:
> Whoops. One of my colleagues suggested that i should name the file
> arch-390x.h. Reason for this is that the architecture name "s390"
> describes the 31bit (compat) architecture mode in userspace, and "s390x"
> the 64 bit mode. To make it a bit more complicated, the architecture in
> the kernel is named "s390". That's because in the beginning the kernel
> could run in 31bit or 64 bit mode, and there can be only one
> architecture name. When support for running 31bit kernels was removed
> years ago, the architecture name s390 was kept because renaming the
> architecture would have been quite some fun. So in short:
> 
> Kernel s390 == 64 bit only
> Userspace s390 == 31 bit
> Userspace s390x == 64 bit

OK, that might be why it's always a bit confusing to me :-)

> So i tried renaming the header file, noted that the Makefile just uses:
> 
> nolibc_arch := $(patsubst arm64,aarch64,$(ARCH))
> arch_file := arch-$(nolibc_arch).h
> 
> which would then need special handling. Obviously i failed to revert the
> change completely during rebase.
> 
> So it should be:
> 
> >> +#elif defined(__s390x__)
> >> +#include "arch-s390.h"
> 
> I'm fine with both - either you fixing it up or me sending a v2.

As you like. If you prefer to rename the file to s390x as your colleague
suggested, I'll then ask you to send a v2. Otherwise either Paul or I can
drop that 'x' in the #include.

Thanks,
Willy