Messages in this thread | | | Date | Mon, 20 Oct 2008 13:28:24 -0400 (EDT) | From | Steven Rostedt <> | Subject | Re: [PATCH 0/2] ftrace: fixes for PPC |
| |
On Mon, 20 Oct 2008, Josh Boyer wrote:
> On Mon, Oct 20, 2008 at 12:30:33PM -0400, Steven Rostedt wrote: > >> Anyway, if you want a tester let me know. It seems 2.6.27.1 should be > >> fine since FTRACE was disabled, but for .28-rc1 it would be cool if it > >> worked :). > > > >Hi Josh, > > > >I've been looking deeper at the code for PPC. I realized that my PPC64 box > >that I've been testing on did not use modules. While looking at the module > >code it dawned on me the dynamic ftrace needs a bit of work. This is > >because the way modules are handled in PPC (and other architectures as > >well). The jmps used by mcount is a 24 bit jump. Since the modules are > >loaded farther than 24bits away, a trampoline is needed. > > Ah, indeed. > > >A bit of rework is needed in the ftrace infrastructure to handle the > >trampoline. Too much work to go into 28. I'll start working on code that > >can hopefully be ready and tested for 29. It's not that major of a change, > >but since the merge window for 28 has already been opened, we would like > >to get a bit more testing in before we hand it over to Linus. > > That seems like a good plan. Should we mark dynamic ftrace as X86 only > in Kconfig for .28 to prevent people from inadvertently setting it?
Well, we probably should disable it for PPC at least. I don't know if sparc has the same issue.
David?
-- Steve
| |