Date:   Thu, 20 Sep 2018 11:24:44 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     firoz.khan@...aro.org
Cc:     linux-m68k <linux-m68k@...ts.linux-m68k.org>,
        y2038 Mailman List <y2038@...ts.linaro.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux-Arch <linux-arch@...r.kernel.org>,
        Arnd Bergmann <arnd@...db.de>,
        Deepa Dinamani <deepa.kernel@...il.com>,
        marcin.juszkiewicz@...aro.org
Subject: Re: [PATCH 2/4] m68k: Replace NR_syscalls macro from asm/unistd.h

Hi Firoz,

On Thu, Sep 20, 2018 at 10:12 AM Firoz Khan <firoz.khan@...aro.org> wrote:
> On 18 September 2018 at 15:34, Geert Uytterhoeven <geert@...ux-m68k.org> wrote:
> > On Tue, Sep 18, 2018 at 9:16 AM Firoz Khan <firoz.khan@...aro.org> wrote:
> >> On 9 August 2018 at 13:00, Geert Uytterhoeven <geert@...ux-m68k.org> wrote:
> >> > One first comment below...
> >> >
> >> > On Thu, Aug 9, 2018 at 7:16 AM Firoz Khan <firoz.khan@...aro.org> wrote:
> >> >> NR_syscalls macro holds the number of system call exist in m68k
> >> >> architecture. This macro is currently the part of asm/unistd.h file.
> >> >> We have to change the value of NR_syscalls, if we add or delete a
> >> >> system call.
> >> >>
> >> >> One of patch in this patch series has a script which will generate
> >> >> a uapi header based on syscall.tbl file. The syscall.tbl file
> >> >> contains the number of system call information. So we have two
> >> >> option to update NR_syscalls value.
> >> >>
> >> >> 1. Update NR_syscalls in asm/unistd.h manually by counting the
> >> >>    no.of system calls. No need to update NR_syscalls untill
> >> >>    we either add a new system call or delete an existing system
> >> >>    call.
> >> >>
> >> >> 2. We can keep this feature it above mentioned script, that'll
> >> >>    count the number of syscalls and keep it in a generated file.
> >> >>    In this case we don't need to explicitly update NR_syscalls
> >> >>    in asm/unistd.h file.
> >> >>
> >> >> The 2nd option will be the recommended one. For that, I moved the
> >> >> NR_syscalls macro from asm/unistd.h to uapi/asm/unistd.h. The macro
> >> >> name also changed form NR_syscalls to __NR_syscalls for making the
> >> >> name convention same across all architecture. While __NR_syscalls
> >> >> isn't strictly part of the uapi, having it as part of the generated
> >> >> header to simplifies the implementation.
> >> >
> >> > It can indeed not be part of the UAPI, as UAPI definitions can never change,
> >> > while new syscalls will be added in the future, increasing the number ;-)
> >>
> >> Thanks for your reply :)
> >> Sorry for the delayed response :(
> >>
> >> I would like to keep __NR_syscalls macro to uapi header in order to simplify
> >> the system call table generation script. Otherwise the __NR_syscalls
> >> macro need to update manually. That become a problem.
> >>
> >> Please check the below implementation in uapi file make sense?
> >> It is an easy workaround to leave __NR_syscalls macro in uapi/asm/unistd.h
> >> and enclose it in #ifdef __KERNEL__
> >>
> >> ...
> >> ...
> >> #define __NR_pwritev2  378
> >> #define __NR_statx      379
> >>
> >> #ifdef __KERNEL__
> >> #define __NR_syscalls   380
> >> #endif
> >> ...
> >> ...
> >
> > #ifdef __KERNEL__ sounds fine to me.
>
> I posted similar script for 10 different architectures. I got few good review
> from the maintainers and it will be applicable for all the
> architectures including
> m68k. There are few area which I identified need to improve. This will take
> couple of days.
>
> But it will be very helpful if you can perform the boot test on the
> actual platform
> and share the result.

Builds and boots fine on ARAnyM (virtual Atari).

So for the full series:
Tested-by: Geert Uytterhoeven <geert@...ux-m68k.org>

However, I noticed the following effective difference between the old
arch/m68k/include/uapi/asm/unistd.h and the new generated
arch/m68k/include/generated/uapi/asm/unistd_32.h:

-/*#define __NR_break            17*/
-/*#define __NR_stty             31*/
-/*#define __NR_gtty             32*/
-/*#define __NR_ftime            35*/
-/*#define __NR_prof             44*/
-/*#define __NR_lock             53*/
-/*#define __NR_mpx              56*/
-/*#define __NR_ulimit           58*/
-/*#define __NR_oldolduname      59*/
-/*#define __NR_profil           98*/
-/*#define __NR_ioperm          101*/
-/*#define __NR_olduname                109*/
-/*#define __NR_iopl            110*/ /* not supported */
-/*#define __NR_idle            112*/ /* Obsolete */
-/*#define __NR_vm86            113*/ /* not supported */
-/*#define __NR_afs_syscall     137*/ /* Syscall for Andrew File System */
-/*#define __NR_vserver         278*/
+#define __NR_break     17
+#define __NR_stty      31
+#define __NR_gtty      32
+#define __NR_ftime     35
+#define __NR_prof      44
+#define __NR_lock      53
+#define __NR_mpx       56
+#define __NR_ulimit    58
+#define __NR_oldolduname       59
+#define __NR_profil    98
+#define __NR_ioperm    101
+#define __NR_olduname  109
+#define __NR_iopl      110
+#define __NR_idle      112
+#define __NR_vm86      113
+#define __NR_afs_syscall       137
+#define __NR_vserver   278

Given userspace code may contain checks for the presence of these
defines, I think they should not be present.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

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