Messages in this thread | | | Date | Thu, 18 Feb 2010 19:13:55 +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 11:19:54AM -0500, Masami Hiramatsu wrote: > 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. > > These APIs are needed for kprobe-tracer on ftrace(kernel/trace/trace_kprobe.c), > which is just a consumer of kprobes (so depends on CONFIG_KPROBES). > > I mean, if you wanna figure out that, you have to select CONFIG_KPROBE_EVENT too :) > And then, gcc tries to compile trace_kprobe.c and quickly dumps error messages > what APIs are not found :)
Yeah.
> > 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. > > yeah, now those APIs depend on pt_regs, so I put it in ptrace.h. > > Thank you,
But anyway, if you prefer I can add a reference to ptrace.h in the config help. We just need to not forgot that if we move these functions later :)
Thanks.
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