Re: [PATCH 2/3] tracing/kprobes: Make Kconfig dependencies generic

[Frederic Weisbecker <fweisbec@gmail.com>]

On Thu, Feb 18, 2010 at 09:01:12AM -0500, Mike Frysinger wrote:
> > --- a/arch/Kconfig
> > +++ b/arch/Kconfig
> > @@ -123,6 +123,10 @@ config USE_GENERIC_SMP_HELPERS
> >
> >  config HAVE_REGS_AND_STACK_ACCESS_API
> >        bool
> > +       help
> > +         This symbol should be selected by an architecure if it supports
> > +         the API needed to access registers and stack entries from pt_regs.
> > +         For example the kprobes-based event tracer needs this API.
> 
> a bit vague ... arent there headers/functions people could look at ?
> perhaps you're talking about the regset functions (which is an API to
> access registers in pt_regs) ?  or you're talking about asm/syscall.h
> (which is an API to access registers in pt_regs) ?
> 
> i'm not asking to be a pain, i'm asking because i really havent a
> clue.  if i wanted to add support for this stuff to the Blackfin arch,
> i wouldnt know where to start.  even after reading this help i'd fall
> back to grepping arch/x86/ and trying to divine a starting point from
> there.


If an arch support kprobes, it just needs to select
HAVE_REGS_AND_STACK_ACCESS_API to figure out quickly what is missing,
as gcc will barf every missing clues you need.

For now it is stored is asm/ptrace.h, but that might be split in
the future, especially as ptrace has initially nothing related to
that. A documentation that deals with filenames or API enumerations
tend to be incidentally async with API evolutions.

Hm?