Re: missing syscalls

[Sam Ravnborg <sam@ravnborg.org>]

On Sun, Apr 01, 2007 at 02:09:47PM -0600, Matthew Wilcox wrote:
> On Sun, Apr 01, 2007 at 12:23:45PM -0700, David Miller wrote:
> > You should hook both of these syscalls up even if the config option
> > that enables them usually is not, or cannot currently be, enabled.
> > 
> > The cond_syscall()'s will make sure they always link properly and
> > provide a -ENOSYS implementation.
> > 
> > Hooking them up makes it easier to check future missed cases without
> > us having to add a plethora of ifdefs to the missing syscall checks
> > for each platform.
> 
> I haven't looked at the missing syscall check implementation, but it seems
> like it's poorly designed if we have to add ifdefs for each arch.  Why not
> allow arches a mechanism to state which syscalls they intentionally
> don't implement?

It's a stupid script so it is easy to fool.
The following patch makes x86_64 shut up:

diff --git a/include/asm-x86_64/unistd.h b/include/asm-x86_64/unistd.h
index c5f596e..6f73918 100644
--- a/include/asm-x86_64/unistd.h
+++ b/include/asm-x86_64/unistd.h
@@ -620,6 +620,9 @@ __SYSCALL(__NR_vmsplice, sys_vmsplice)
 #define __NR_move_pages		279
 __SYSCALL(__NR_move_pages, sys_move_pages)
 
+#define __NR_getcpu             /* 318 - not relevant */
+#define __NR_epoll_pwait        /* 319 - not relevant */
+
 #define __NR_syscall_max __NR_move_pages
 
 #ifndef __NO_STUBS

NOTE - I am NOT proposing this patch. It is purely an example how
to in an arch specific fashion to shut up the syscall check.