Russell King wrote:

On Fri, Mar 09, 2007 at 11:40:08AM -0800, H. Peter Anvin wrote:

quoted

Jan-Benedict Glaw wrote:

quoted

Not everybody has a simple indexed list of pointers :)  For example,
for vax-linux, we use a struct per syscall with the expected number of
on-stack longwords for the call.

So if something "new" is coming up, please keep in mind that it should
be flexible enough to represent that. :)

I discussed with Al Viro a while ago about using something like the 
SYSCALLS.def file from klibc as the source format for the system calls. 
 That would deal very flexibly with almost all kinds of stub generation.

Hopefully with this idea in place, we can spot new syscalls before
the final release of the kernel (maybe kautobuild can help there)
and fix any silly system call argument ordering which requires
different architectures to have different syscall prototypes (eg,
sys_arm_fadvise64_64 vs sys_fadvise64_64, sys_arm_sync_file_range vs
sys_sync_file_range).

That would definitely be nice.

Otherwise the SYSCALLS.def file will probably end up being full of
ifdefs.

... which exactly mirrors the pain and suffering which libc maintainers 
have to deal with.  The amount of time I spent per line of code in klibc 
is quite high, in part because I wanted it to be as self-porting as was 
possible.  I've really tried to avoid arch-specific hacks, and yet there 
are more there than there should be, in large part because of unusable 
or missing kernel header exports.

	-hpa