linux-kernel - Re: [PATCH v3 5/6] mips: add system call table generation support

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Message-ID: <CALxhOnivqOdpZ8WRK3Lx9ScApa34MS6riTwFz15aS7GTGf6QQA@mail.gmail.com>
Date:   Fri, 30 Nov 2018 10:35:02 +0530
From:   Firoz Khan <firoz.khan@...aro.org>
To:     Arnd Bergmann <arnd@...db.de>
Cc:     "open list:RALINK MIPS ARCHITECTURE" <linux-mips@...ux-mips.org>,
        Ralf Baechle <ralf@...ux-mips.org>,
        Paul Burton <paul.burton@...s.com>,
        James Hogan <jhogan@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Philippe Ombredanne <pombredanne@...b.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Kate Stewart <kstewart@...uxfoundation.org>,
        y2038 Mailman List <y2038@...ts.linaro.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux-Arch <linux-arch@...r.kernel.org>,
        Deepa Dinamani <deepa.kernel@...il.com>,
        Marcin Juszkiewicz <marcin.juszkiewicz@...aro.org>
Subject: Re: [PATCH v3 5/6] mips: add system call table generation support

Hi Arnd,

Thanks for your email.

On Thu, 29 Nov 2018 at 19:46, Arnd Bergmann <arnd@...db.de> wrote:
>
> On Thu, Nov 29, 2018 at 9:44 AM Firoz Khan <firoz.khan@...aro.org> wrote:
> >
> > The system call tables are in different format in all
> > architecture and it will be difficult to manually add,
> > modify or delete the syscall table entries in the res-
> > pective files. To make it easy by keeping a script and
> > which will generate the uapi header and syscall table
> > file. This change will also help to unify the implemen-
> > tation across all architectures.
> >
> > The system call table generation script is added in
> > kernel/syscalls directory which contain the scripts to
> > generate both uapi header file and system call table
> > files. The syscall.tbl will be input for the scripts.
> >
> > syscall.tbl contains the list of available system calls
> > along with system call number and corresponding entry
> > point. Add a new system call in this architecture will
> > be possible by adding new entry in the syscall.tbl file.
> >
> > Adding a new table entry consisting of:
> >         - System call number.
> >         - ABI.
> >         - System call name.
> >         - Entry point name.
> >         - Compat entry name, if required.
> >
> > syscallhdr.sh and syscalltbl.sh will generate uapi
> > header unistd_64/n32/o32.h and syscall_table_32_o32/-
> > 64_64/64-n32/64-o32.h files respectively. Both .sh files
> > will parse the content syscall.tbl to generate the header
> > and table files. unistd_64/n32/o32.h will be included by
> > uapi/asm/unistd.h and syscall_table_32_o32/64_64/64-n32-
> > /64-o32.h is included by kernel/syscall_table32_o32/64-
> > _64/64-n32/64-o32.S - the real system call table.
> >
> > ARM, s390 and x86 architecuture does have similar support.
> > I leverage their implementation to come up with a generic
> > solution.
> >
> > Signed-off-by: Firoz Khan <firoz.khan@...aro.org>
>
> Ah, I see you added the syscallnr.sh script from ARM.  I guess
> that is one way to handle it, and the implementation seems
> fine. It would be good to mention it in the changelog text above
> though.

I came across the file name - syscallnr.sh  in ARM long back and I
used it here.

Everyone - Arnd pointed out __NR_syscalls assignment issue in my
v2 patches. For that, I came across those macros to be part of the
generated file. So I created another script - syscallnr.sh just write
__NR_N32/N64/O32_Linux, __NR_N32/N64/O32_Linux_syscalls
to the generated file. I had 1:1 chat with Paul also and he share few
concerns to convert above macros to be variable.

The advantage of adding another script is the other two scripts -
syscallhdr.sh and syscalltbl.sh are identical across all other 10
architecture. If we are trying to come up with a common script,
hopefully the effort will be minimal.

Yes, I can update the change log.

Paul, Could you help me to review this patch series and perform
the boot test on actual platform.

FYI, I could send v4 (clean one) next week mid as I'm on a vacation
couple of days.

Thanks
Firoz





>
>       Arnd