Messages in this thread | | | Date | Wed, 22 Oct 2008 15:16:33 -0400 (EDT) | From | Steven Rostedt <> | Subject | Re: [PATCH 04/11] ftrace: comment arch ftrace code |
| |
On Wed, 22 Oct 2008, Andrew Morton wrote: > > I dunno. > > __copy_to_user_inatomic() is for "copying memory from userspace while > in an atomic context". > > But what you're doing here is "modifying some kernel text which might > generate a fault". It seems somewhat interface-abusive to use a > userspace access function for that just because it happens right now to > do the right thing. > > I'd suggest that for clarity and for future-safety, you create some new > interface function which does that thing. Right now it can be a simple > wrapper around __copy_from_user_inatomic(). > > <looks> > > oh, someone added one - probe_kernel_write(). Why not use that?
I didn't know about that code. That is what I want.
-- Steve
> > <wonders why he doesn't know what's going on any more> > > > Also, I hope that the above code is called from within a > pagefault_disable()d region? Or are relying upon some magical > side-effect of something which happens to do the same thing as > pagefault_disable()? IOW: by what means does the above code ensure > that do_page_fault() will see in_atomic()==true?
This code is called from kstop_machine, or simply has interrupts disabled.
-- Steve
| |