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

[Mike Frysinger <vapier.adi@gmail.com>]

On Thu, Feb 18, 2010 at 08:25, Heiko Carstens wrote:
> On Thu, Feb 18, 2010 at 01:34:57PM +0100, Frederic Weisbecker wrote:
>> On Thu, Feb 18, 2010 at 07:12:08AM -0500, Mike Frysinger wrote:
>> > On Thu, Feb 18, 2010 at 07:09, Heiko Carstens wrote:
>> > > On Thu, Feb 18, 2010 at 06:18:20AM -0500, Mike Frysinger wrote:
>> > >> On Thu, Feb 18, 2010 at 06:13, Frederic Weisbecker wrote:
>> > >> > --- a/arch/Kconfig
>> > >> > +++ b/arch/Kconfig
>> > >> > @@ -121,6 +121,9 @@ config HAVE_DMA_ATTRS
>> > >> >  config USE_GENERIC_SMP_HELPERS
>> > >> >        bool
>> > >> >
>> > >> > +config HAVE_REGS_AND_STACK_ACCESS_API
>> > >> > +       bool
>> > >> > +
>> > >>
>> > >> could you add an appropriate help/comment so arch peeps know what
>> > >> needs to be implemented before they can select this
>> > >
>> > > That's why I added the commit ID for the regs and stack access api
>> > > to the changelog. imho that should be sufficient.
>> > > Besides that the next commit would implement it for s390 as a
>> > > blueprint for others. That is... for those that missed the initial
>> > > x86 implementation.
>> >
>> > people shouldnt have to dive into the changelog to try and divine
>> > documentation.  it's hardly standard, so people fall on it in a
>> > pima-last-resort kind of way.  being explicit in the file up front by
>> > writing real documentation says other people a lot more time.
>> > -mike
>>
>>
>> Yeah, would be nice to have a comment above the config definition
>> to explain what it implies.
>>
>> Heiko, mind sending a delta patch for that?
>
> Subject: [PATCH] tracing/kprobes: add short documentation for HAVE_REGS_AND_STACK_ACCESS_API
>
> From: Heiko Carstens <heiko.carstens@de.ibm.com>
>
> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
> ---
>  arch/Kconfig |    4 ++++
>  1 file changed, 4 insertions(+)
>
> --- 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.
-mike