Re: [PATCH v6 00/13] syscalls: Add a shared table for all archs

[André Almeida]

Em 15/09/2026 04:45, Arnd Bergmann escreveu:
> On Sat, Aug 29, 2026, at 01:19, André Almeida wrote:
> > While implementing a new syscall, we need to wire up it's number to the arch
> > table. Since syscall number 403, all architectures are on sync regarding the
> > number (except alpha), which make things a lot easier but more repetitive as
> > well. Have a look at commit b36d4b6aa88 ("arch: hookup listns() system call"),
> > with 15 lines of mostly:
> >
> >    +470    common  listns                          sys_listns
> >
> > There's already a "common" table shared with a bunch of archs at
> > `scripts/syscall.tbl`, but due to historical reasons some archs will never be
> > able to move to this table and share all the numbers.
> >
> > The generic table starts from 403 (clock_gettime64), the first common syscall.
> >
> > I've compile tested for arm32, arm64, s390, mips, sparc and alpha by comparing
> > the syscalls_*.h and unistd_*.h files generated before and after this patchset.
> > For most of cases the files are identical, for the few cases that they are not,
> > there's a note in the commit explaining why they are equivalent.
>
> I've tried merging these for the asm-generic tree now, and would like to
> send them for 7.4.
>
> Unfortunately, the build bot flagged problems on mips, see the patch below
> for my workarounds=, but I think we have to improve that still and didn't
> just fold it into your patch.
>
> As you took out the dependencies on the syscall_*.tbl files, the
> output does not get rebuilt if changes are made to the table, and I
> have not come up with a good solution for mips. My hack just adds both
> input files to all outputs, which works but is not technically correct.

Thanks for testing! I believe I found a simple solution for this. I 
modified syscall_o32.tbl and can confirm it triggers a rebuild now:

diff --git a/arch/mips/kernel/syscalls/Makefile 
b/arch/mips/kernel/syscalls/Makefile
index aaa5443ea906..9e31d1ce5015 100644
--- a/arch/mips/kernel/syscalls/Makefile
+++ b/arch/mips/kernel/syscalls/Makefile
@@ -40,10 +40,10 @@ src_n32 := $(src)/syscall_n.tbl
 src_n64 := $(src)/syscall_n.tbl
 src_o32 := $(src)/syscall_o32.tbl

-$(kapi)/unistd_nr_%.h: $(systbl_common) $(sysnr) FORCE
+$(kapi)/unistd_nr_%.h: $(systbl_common) $(src_%) $(sysnr) FORCE
        $(call if_changed,sysnr)

-$(kapi)/syscall_table_%.h: $(systbl) $(systbl_common) FORCE
+$(kapi)/syscall_table_%.h: $(systbl) $(systbl_common) $(src_%) FORCE
        $(call if_changed,systbl)

 uapisyshdr-y           += unistd_n32.h                 \

> The rt_sigtimedwait and ustat entries had a typo that caused a link
> error, but I did not check if there were any additional mistakes that
> caused incorrect output data without causing a link failure.

Ops, my bad. I had another round comparing the tables, and I found 
another case that needed a fix:

diff --git a/arch/mips/kernel/syscalls/syscall_n.tbl 
b/arch/mips/kernel/syscalls/syscall_n.tbl
index e3d278f715b7..1882527053af 100644
--- a/arch/mips/kernel/syscalls/syscall_n.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n.tbl
@@ -43,7 +43,7 @@
 33     common  pause                           sys_pause
 34     common  nanosleep                       sys_nanosleep 
sys_nanosleep_time32
 35     common  getitimer                       sys_getitimer 
compat_sys_getitimer
-36     common  setitimer                       sys_setitimer 
compat_setitimer
+36     common  setitimer                       sys_setitimer 
compat_sys_setitimer
 37     common  alarm                           sys_alarm
 38     common  getpid                          sys_getpid
 39     common  sendfile                        sys_sendfile64 
compat_sys_sendfile

Let me know if both diffs look good to you, and then I can send a v7.

Thanks!

>         Arnd
>
> diff --git a/arch/mips/kernel/syscalls/Makefile b/arch/mips/kernel/syscalls/Makefile
> index aaa5443ea906..51b9939ecff0 100644
> --- a/arch/mips/kernel/syscalls/Makefile
> +++ b/arch/mips/kernel/syscalls/Makefile
> @@ -40,10 +40,10 @@ src_n32 := $(src)/syscall_n.tbl
>   src_n64 := $(src)/syscall_n.tbl
>   src_o32 := $(src)/syscall_o32.tbl
>   
> -$(kapi)/unistd_nr_%.h: $(systbl_common) $(sysnr) FORCE
> +$(kapi)/unistd_nr_%.h: $(src_o32) $(src_n64) $(systbl_common) $(sysnr) FORCE
>          $(call if_changed,sysnr)
>   
> -$(kapi)/syscall_table_%.h: $(systbl) $(systbl_common) FORCE
> +$(kapi)/syscall_table_%.h: $(src_o32) $(src_n64) $(systbl) $(systbl_common) FORCE
>          $(call if_changed,systbl)
>   
>   uapisyshdr-y           += unistd_n32.h                 \
> diff --git a/arch/mips/kernel/syscalls/syscall_n.tbl b/arch/mips/kernel/syscalls/syscall_n.tbl
> index e3d278f715b7..84c35c1f0c3e 100644
> --- a/arch/mips/kernel/syscalls/syscall_n.tbl
> +++ b/arch/mips/kernel/syscalls/syscall_n.tbl
> @@ -133,14 +133,14 @@
>   123    common  capget                          sys_capget
>   124    common  capset                          sys_capset
>   125    common  rt_sigpending                   sys_rt_sigpending       compat_sys_rt_sigpending
> -126    common  rt_sigtimedwait                 sys_rt_sigtimedwait_time        compat_sys_rt_sigtimedwait_time32
> +126    common  rt_sigtimedwait                 sys_rt_sigtimedwait     compat_sys_rt_sigtimedwait_time32
>   127    common  rt_sigqueueinfo                 sys_rt_sigqueueinfo     compat_sys_rt_sigqueueinfo
>   128    common  rt_sigsuspend                   sys_rt_sigsuspend       compat_sys_rt_sigsuspend
>   129    common  sigaltstack                     sys_sigaltstack         compat_sys_sigaltstack
>   130    common  utime                           sys_utime               sys_utime32
>   131    common  mknod                           sys_mknod
>   132    common  personality                     sys_personality         sys_32_personality
> -133    common  ustat                           sys_usta                compat_sys_usta
> +133    common  ustat                           sys_ustat               compat_sys_ustat
>   134    common  statfs                          sys_statfs              compat_sys_statfs
>   135    common  fstatfs                         sys_fstatfs             compat_sys_fstatfs
>   136    common  sysfs                           sys_sysfs