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

[André Almeida]

Em 17/09/2026 02:55, Arnd Bergmann escreveu:
> On Thu, Sep 17, 2026, at 00:19, André Almeida wrote:
> > Em 15/09/2026 04:45, Arnd Bergmann escreveu:
> > > On Sat, Aug 29, 2026, at 01:19, André Almeida wrote:
> >
> > 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)
>
> I had tried the same thing already, but in my testing, it did
> not rebuild after changing the syscall_n.tbl file, only the
> syscall_o32.tbl file. Can you verify that your change rebuilds
> all nine files in the correct cases?
After a more careful look, I have found out a couple of issues:

- The first one, the one that the build bot originally warned as about 
this outdated rule:

 $(uapi)/unistd_%.h: $(src)/syscall_%.tbl $(syshdr) FORCE
 	$(call if_changed,syshdr)

$(src)/syscall_%.tbl doesn't make anymore for n32 and n64, and needed to 
be updated.

- Secondly, $(src_%) doesn't work as I expected. % only works like this 
for files (like syscall_%.tbl). For variables, the correct form is 
$(src_$*). Now the pattern matching started working and generating 
$(src_n32), $(src_n64), ...

- Finally, this wasn't enough either. Due to how make works[1], the 
variable was being generated but it wasn't being evaluated. So I had to 
add the .SECONDEXPANSION target to finally make it work, resulting on 
those rules:

.SECONDEXPANSION:

$(uapi)/unistd_%.h: $(systbl_common) $$(src_$$*) $(syshdr) FORCE
	$(call if_changed,syshdr)

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

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

And now, testing updating the tables:

$ touch arch/mips/kernel/syscalls/syscall_o32.tbl
$ make -j31 W=1 O=mips ARCH=mips LLVM=1 prepare | grep SYS
  SYSHDR  arch/mips/include/generated/uapi/asm/unistd_o32.h
  SYSTBL  arch/mips/include/generated/asm/syscall_table_o32.h
  SYSNR   arch/mips/include/generated/asm/unistd_nr_o32.h

$ touch arch/mips/kernel/syscalls/syscall_n.tb
$ make -j31 W=1 O=mips ARCH=mips LLVM=1 prepare | grep SYS
  SYSHDR  arch/mips/include/generated/uapi/asm/unistd_n32.h
  SYSHDR  arch/mips/include/generated/uapi/asm/unistd_n64.h
  SYSTBL  arch/mips/include/generated/asm/syscall_table_n32.h
  SYSTBL  arch/mips/include/generated/asm/syscall_table_n64.h
  SYSNR   arch/mips/include/generated/asm/unistd_nr_n32.h
  SYSNR   arch/mips/include/generated/asm/unistd_nr_n64.h

$ touch scripts/syscall_common.tbl
$ make -j31 W=1 O=mips ARCH=mips LLVM=1 prepare | grep SYS
  SYSHDR  arch/mips/include/generated/uapi/asm/unistd_n32.h
  SYSHDR  arch/mips/include/generated/uapi/asm/unistd_n64.h
  SYSHDR  arch/mips/include/generated/uapi/asm/unistd_o32.h
  SYSTBL  arch/mips/include/generated/asm/syscall_table_n32.h
  SYSTBL  arch/mips/include/generated/asm/syscall_table_n64.h
  SYSTBL  arch/mips/include/generated/asm/syscall_table_o32.h
  SYSNR   arch/mips/include/generated/asm/unistd_nr_n32.h
  SYSNR   arch/mips/include/generated/asm/unistd_nr_n64.h
  SYSNR   arch/mips/include/generated/asm/unistd_nr_o32.h

I will send a v7 with this changes for mips.

Thanks!

[1] 
https://www.gnu.org/software/make/manual/html_node/Secondary-Expansion.html