Messages in this thread | | | Date | Thu, 24 Apr 2008 20:42:44 +0200 | From | Michal Simek <> | Subject | Re: microblaze syscall list |
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Hi Arnd,
>> I would like to fix syscalls in Microblaze repo. Can you give me a hint how to >> do it? > > I think we need to do it on a case-by-case basis, best here on the > linux-arch mailing list. I'm sure there are some controversial ones, > but most should be pretty clear. > >> I look at Blackfin arch and I compared files with microblaze. There are some >> differences but not so much. >> Can you tell me how to test it which syscall is necessary for platform. >> I have never found any documentation about. > > Hopefully we can get to this kind of documentation by the end of this > discussion. scripts/checksyscalls.sh is some part of the documentation, > and we can refine that. :-)
> Maybe we can even have an asm-generic/unistd.h that defines all the > still relevant syscalls, plus a per-architecture range that you can > use for microblaze-specific calls in your own unistd.h.
That will be really useful. Good idea.
>> In my syscall_table.S (on some arch in entry.S) is one big jump table with >> reference to syscalls. In unistd.h is definition. >> >> Is there any convention which syscalls are use for all archs and which are >> architecture specific? > > Not really. There are very few syscalls that are needed only on certain > architectures. The more common case is that a syscall has been replaced > by a more complex interface, and a new architecture only needs one of the > two, while older architectures still need both. > > Let me just comment on your syscall table as it is today: > >> ENTRY(sys_call_table) >> .long sys_restart_syscall /* 0 - old "setup()" system call, >> * used for restarting */ > > The comment is irrelevant and misleading -- microblaze never had sys_setup.
I removed this comment.
>> .long sys_exit >> .long sys_ni_syscall /* was fork */ > > it might be useful to renumber your calls once all the irrelevant ones > have been removed, so you can get rid of all the sys_ni_syscalls here.
I'll delete all sys_ni_syscall from syscall_table.S and I'll remove it from unistd.h too. I hope I'll keep the same call numbers.
>> .long sys_read >> .long sys_write >> .long sys_open /* 5 */ > > Since we have all the new sys_*at calls like openat, we don't really > need the old versions any more. The kernel implementation of sys_open > basically calls openat. You could do the same in libc instead. > Don't know if that's worth it though, opinions?
I looked at it and there are the different arguments for open and openat syscalls. Implementation is almost the same. I keep it now.
>> .long sys_close >> .long sys_waitpid > > waitpid and wait4 can be replaced with waitid
Can I keep number of syscall(unistd.h) and only add reference to waitid in syscall_table? or just remove?
>> .long sys_creat >> .long sys_link >> .long sys_unlink /* 10 */ >> .long sys_execve_wrapper > > having an execve_wrapper instead of execve looks like a strange convention, > though I guess you had a good reason for it, could you explain? > > This one looks architecture specific, so you may want to rename it > microblaze_execve_wrapper instead of sys_execve_wrapper.
I looked at it and the same of style is used in arm (arch/arm/kernel/entry-common.S) and some others arch. This wrapper only set one parameter to correct pointer to stack.
I'll comment the rest later. I need time to look at it.
Thanks for your big help. I really appreciate this.
Michal
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