From: Ian Munsie on
Hi Jason,

I'm currently in the process of implementing syscall tracepoints for
PowerPC, and a considerable amount of my work is going to end up
requiring these patches of yours. I've reviewed and tested your patches
(and spent a good chunk of time rebasing them on top of
tip/tracing/core) and they all seem pretty good.

I *particularly* like the way in which they prevent ftrace syscalls from
reporting that sys_swapoff was constantly firing on x86_64 kernels with
a 32bit userspace ;)

Anyway, I'm just wondering if you have an ETA for the v4 patchset to
address the remaining issues that Frederic raised so that they can be
merged.

Cheers,
-Ian

Excerpts from Jason Baron's message of Wed Mar 17 04:46:08 +1100 2010:
> Hi,
>
> Re-post to add infrastructure for compat syscall event tracing support. This
> patch series also adds x86_64 arch specific support as an example consumer
> of the new infrastructure.
>
> Arches can request compat syscall tracing by setting:
> __HAVE_ARCH_FTRACE_COMPAT_SYSCALLS, if CONFIG_COMPAT and CONFIG_FTRACE_SYSCALLS
> are set. Arches then need to implement the following interfaces:
>
> 1) int is_compat_task(void);
> - most arches seem to have this already
> 2) unsigned long arch_compat_syscall_addr(int nr);
> - returns a pointer to the compat syscall entry corresponding to syscall 'nr'
> 3) int NR_syscalls_compat;
> - number of entries in the compat syscall table.
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From: Jason Baron on
On Fri, May 21, 2010 at 07:40:21PM +1000, Ian Munsie wrote:
> Hi Jason,
>
> I'm currently in the process of implementing syscall tracepoints for
> PowerPC, and a considerable amount of my work is going to end up
> requiring these patches of yours. I've reviewed and tested your patches
> (and spent a good chunk of time rebasing them on top of
> tip/tracing/core) and they all seem pretty good.
>
> I *particularly* like the way in which they prevent ftrace syscalls from
> reporting that sys_swapoff was constantly firing on x86_64 kernels with
> a 32bit userspace ;)
>
> Anyway, I'm just wondering if you have an ETA for the v4 patchset to
> address the remaining issues that Frederic raised so that they can be
> merged.
>
> Cheers,
> -Ian
>

hi Ian,

I think the main issue left was that I am using the same meta data for
both the 32-bit and 64-bit table entries, when they reference the same
syscall. for example, for x86 both the compat and underlying 64-bit
kernel reference 'sys_rename'. Thus, i am pointing both perf events at
the same meta data. Frederic was saying they need to be separate. I'm
not sure i completely understand why, since the 32-bit are just sign
extended to 64-bit in this case. Frederic, perhaps, you can explain this
a bit more for me?

thanks,

-Jason
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From: Frederic Weisbecker on
On Fri, May 21, 2010 at 09:24:07AM -0400, Jason Baron wrote:
> On Fri, May 21, 2010 at 07:40:21PM +1000, Ian Munsie wrote:
> > Hi Jason,
> >
> > I'm currently in the process of implementing syscall tracepoints for
> > PowerPC, and a considerable amount of my work is going to end up
> > requiring these patches of yours. I've reviewed and tested your patches
> > (and spent a good chunk of time rebasing them on top of
> > tip/tracing/core) and they all seem pretty good.
> >
> > I *particularly* like the way in which they prevent ftrace syscalls from
> > reporting that sys_swapoff was constantly firing on x86_64 kernels with
> > a 32bit userspace ;)
> >
> > Anyway, I'm just wondering if you have an ETA for the v4 patchset to
> > address the remaining issues that Frederic raised so that they can be
> > merged.
> >
> > Cheers,
> > -Ian
> >
>
> hi Ian,
>
> I think the main issue left was that I am using the same meta data for
> both the 32-bit and 64-bit table entries, when they reference the same
> syscall. for example, for x86 both the compat and underlying 64-bit
> kernel reference 'sys_rename'. Thus, i am pointing both perf events at
> the same meta data. Frederic was saying they need to be separate. I'm
> not sure i completely understand why, since the 32-bit are just sign
> extended to 64-bit in this case. Frederic, perhaps, you can explain this
> a bit more for me?
>
> thanks,
>
> -Jason


If they are pointing to the same function with the same parameters, then
yeah it's fine.

I think I worried about two different handlers that don't have the
exact same parameters (one having compat things, and the other having
not). But now that I think about it that's probably not what you did.

I'll give another shot to this patchset then, as I've probably confused
something, I just need to wait a bit for the giant patchset from Steve
on trace events to be applied, before applying this set. Should happen
soon.

Will look at this next week.
Thanks.

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From: Ian Munsie on
Excerpts from Jason Baron's message of Fri May 21 23:24:07 +1000 2010:
> On Fri, May 21, 2010 at 07:40:21PM +1000, Ian Munsie wrote:
> > Hi Jason,
> >
> > I'm currently in the process of implementing syscall tracepoints for
> > PowerPC, and a considerable amount of my work is going to end up
> > requiring these patches of yours. I've reviewed and tested your patches
> > (and spent a good chunk of time rebasing them on top of
> > tip/tracing/core) and they all seem pretty good.
> >
> > I *particularly* like the way in which they prevent ftrace syscalls from
> > reporting that sys_swapoff was constantly firing on x86_64 kernels with
> > a 32bit userspace ;)
> >
> > Anyway, I'm just wondering if you have an ETA for the v4 patchset to
> > address the remaining issues that Frederic raised so that they can be
> > merged.
> >
> > Cheers,
> > -Ian
> >
>
> hi Ian,
>
> I think the main issue left was that I am using the same meta data for
> both the 32-bit and 64-bit table entries, when they reference the same
> syscall. for example, for x86 both the compat and underlying 64-bit
> kernel reference 'sys_rename'. Thus, i am pointing both perf events at
> the same meta data. Frederic was saying they need to be separate. I'm
> not sure i completely understand why, since the 32-bit are just sign
> extended to 64-bit in this case. Frederic, perhaps, you can explain this
> a bit more for me?
>
> thanks,
>
> -Jason

Hi Jason,

I'm currently cleaning up my patch series for ftrace syscalls on PowerPC
and want to release it soon.

It's probably easiest for me if I release your compat syscall support v3
patches as part of the series. You'd still be marked as the author of
those commits - the only changes I have made to them was rebasing them
against the current tip tree and resolving the conflicts that I came
across.

Is that OK with you? Otherwise I can wait until you put out the v4
patches then rebase mine on top of those.

Cheers,
-Ian
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From: Frederic Weisbecker on
On Thu, Jun 17, 2010 at 05:39:07PM +1000, Ian Munsie wrote:
> Excerpts from Jason Baron's message of Fri May 21 23:24:07 +1000 2010:
> > On Fri, May 21, 2010 at 07:40:21PM +1000, Ian Munsie wrote:
> > > Hi Jason,
> > >
> > > I'm currently in the process of implementing syscall tracepoints for
> > > PowerPC, and a considerable amount of my work is going to end up
> > > requiring these patches of yours. I've reviewed and tested your patches
> > > (and spent a good chunk of time rebasing them on top of
> > > tip/tracing/core) and they all seem pretty good.
> > >
> > > I *particularly* like the way in which they prevent ftrace syscalls from
> > > reporting that sys_swapoff was constantly firing on x86_64 kernels with
> > > a 32bit userspace ;)
> > >
> > > Anyway, I'm just wondering if you have an ETA for the v4 patchset to
> > > address the remaining issues that Frederic raised so that they can be
> > > merged.
> > >
> > > Cheers,
> > > -Ian
> > >
> >
> > hi Ian,
> >
> > I think the main issue left was that I am using the same meta data for
> > both the 32-bit and 64-bit table entries, when they reference the same
> > syscall. for example, for x86 both the compat and underlying 64-bit
> > kernel reference 'sys_rename'. Thus, i am pointing both perf events at
> > the same meta data. Frederic was saying they need to be separate. I'm
> > not sure i completely understand why, since the 32-bit are just sign
> > extended to 64-bit in this case. Frederic, perhaps, you can explain this
> > a bit more for me?
> >
> > thanks,
> >
> > -Jason
>
> Hi Jason,
>
> I'm currently cleaning up my patch series for ftrace syscalls on PowerPC
> and want to release it soon.
>
> It's probably easiest for me if I release your compat syscall support v3
> patches as part of the series. You'd still be marked as the author of
> those commits - the only changes I have made to them was rebasing them
> against the current tip tree and resolving the conflicts that I came
> across.



Perfect! I was about to ask Jason to rebase his patchset against latest -tip.

If you send this set, please also add your own Signed-off-by.

Thanks.

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