Re: [v2,1/1] powerpc: Individual System V IPC system calls

[Sam Bobroff <sam.bobroff@au1.ibm.com>]

On Wed, Oct 14, 2015 at 08:38:15PM +1100, Michael Ellerman wrote:
> On Wed, 2015-10-14 at 18:00 +1100, Sam Bobroff wrote:
> > On Tue, Oct 13, 2015 at 08:38:42PM +1100, Michael Ellerman wrote:
> > > On Tue, 2015-13-10 at 01:49:28 UTC, Sam bobroff wrote:
> > > > This patch provides individual system call numbers for the following
> > > > System V IPC system calls, on PowerPC, so that they do not need to be
> > > > multiplexed:
> > > > * semop, semget, semctl, semtimedop
> > > > * msgsnd, msgrcv, msgget, msgctl
> > > > * shmat, shmdt, shmget, shmctl
> > > 
> > > You tested this right? :)  Tell me about it.
> > 
> > Why yes I did:
> 
> ...
> 
> > (I also re-ran the tests both for little-endian and big-endian hosts.)
> 
> Did you test on 32-bit at all?

I ran the test program, compiled for 32 and 64 bit, on a biarch power7 machine
(using -m32 and -m64 to the compiler) but only to verify that the fully patched
system succeeded. Is that sufficient?

> > It would obviously be good to have someone else test this, but I can't see a
> > way to make it easy to do. They would presumably have to go through all of the
> > above, which seems too much to ask given how trivial the kernel side of the
> > patch is. Still, it bothers me a bit so if there is any way please let me know.
> > (I thought about writing some assembly to directly test the syscall numbers but
> > all it would do is verify that the numbers are valid, which really isn't much
> > of a test.)
> 
> Actually that is still a useful test, it at least tells you if the kernel
> you're running on implements the syscalls. Obviously if you're on mainline
> that's easy enough to work out from the git history, but if/when these get
> backported to distro kernels, it's often harder to work out what's in the
> source than just testing it directly.

Oh, fair enough then.

> So I wrote a quick dirty test for that, it seems to work for me:

[snip]

Thanks :-)

> Which gives:
> 
> test: ipc_unmuxed
> tags: git_version:v4.3-rc3-44-g10053fa531a8-dirty
> Testing semop	returned -1, errno 22
> Testing semget	returned -1, errno 2
> Testing semctl	returned -1, errno 22
> Testing semtimedop	returned -1, errno 22
> Testing msgsnd	returned -1, errno 14
> Testing msgrcv	returned -1, errno 22
> Testing msgget	returned -1, errno 2
> Testing msgctl	returned -1, errno 22
> Testing shmat	returned -1, errno 22
> Testing shmdt	returned -1, errno 22
> Testing shmget	returned -1, errno 2
> Testing shmctl	returned -1, errno 22
> success: ipc_unmuxed
> 
> 
> And on an unpatched system:
> 
> test: ipc_unmuxed
> tags: git_version:v4.3-rc3-44-g10053fa531a8-dirty
> Testing semop	returned -1, errno 38
> [FAIL] Test FAILED on line 2
> failure: ipc_unmuxed
> 
> 
> Look OK?

Yep! And 38 (ENOSYS) is the code we'd expect in the failure case.

> cheers

Cheers,
Sam.