Messages in this thread | | | Date | Thu, 18 Feb 2010 16:43:02 +0100 | From | Frederic Weisbecker <> | Subject | Re: [PATCH 2/3] tracing/kprobes: Make Kconfig dependencies generic |
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On Thu, Feb 18, 2010 at 10:02:52AM -0500, Mike Frysinger wrote: > On Thu, Feb 18, 2010 at 09:50, Frederic Weisbecker wrote: > > 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. > > so should this new Kconfig option have an appropriate depends on > KPROBES or something ?
No, kprobes events need KPROBES and the above one, but KPROBES alone can perfectely work without HAVE_REGS_AND_STACK_ACCESS_API.
> > 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. > > i dont expect there to be per-function documentation here ... such > things below in the header files themselves (linux/regset.h is an > example of how to approach this). but having a tip of reading a file > or two (like HAVE_ARCH_TRACEHOOK) doesnt bit rot nearly as often. if > the common API expected of headers hasnt yet been split, then i guess > not much left to be done here.
Yeah. Once it's split up from ptrace, we can think about a more dedicated header file and then it can be reasonable to put the header filename in the documentation. But not for now IMHO.
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