Messages in this thread | | | Date | Tue, 4 Mar 2014 00:53:06 +0000 | From | Russell King - ARM Linux <> | Subject | Re: [PATCH v6 00/14] uprobes: Add uprobes support for ARM |
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On Mon, Mar 03, 2014 at 09:50:39PM +0100, Oleg Nesterov wrote: > On 03/02, David Long wrote: > > > > Oleg, > > > > I've been looking at arch/Kconfig and kernel/trace/Kconfig where they > > deal with uprobes. The relevant items are CONFIG_UPROBES and > > CONFIG_UPROBE_EVENT. It just doesn't look right to me. > > Yes, this looks strange. I never understood these dependencies. In fact > I even never tried. And I do not really understand kbuild, unfortunately... > > >> --- a/arch/Kconfig > >> +++ b/arch/Kconfig > >> @@ -87,7 +87,8 @@ config KPROBES_ON_FTRACE > >> > >> config UPROBES > >> bool "Transparent user-space probes (EXPERIMENTAL)" > >> - depends on UPROBE_EVENT && PERF_EVENTS > >> + depends on ARCH_SUPPORTS_UPROBES > >> + depends on PERF_EVENTS > > And why CONFIG_UPROBES should depend on PERF_EVENTS? uprobes can be > used by (say) systemtap without UPROBE_EVENT/PERF_EVENTS. > > But as Russell pointed out the events directory is only built if > CONFIG_PERF_EVENTS=y, so it should depend on it or select... > > > I dunno. Personally I vote for the patch from Srikar in > > http://article.gmane.org/gmane.linux.kernel/1017186 > > This is what we currently have, currently CONFIG_UPROBES is not > user-selectable anyway.
Yes, me too, but with the proviso that UPROBE_EVENT also sorts itself out with PERF_EVENTS in some way too (either by selecting it, which IMHO isn't nice, or by depending on it, or the build dependency itself gets sorted.)
Maybe a simpler answer would be to change the build stuff (hand-crafted):
kernel/Makefile -obj-$(CONFIG_PERF_EVENTS) += events/ +obj-y += events/
and kernel/events/Makefile:
-obj-y := core.o ring_buffer.o callchain.o +perf-y := core.o ring_buffer.o callchain.o
-obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o +perf-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o + +obj-${CONFIG_PERF_EVENTS) += $(perf-y)
?
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