Re: 2.6.37-rc1 build failure

[Ingo Molnar <mingo@elte.hu>]

* Peter Zijlstra <peterz@infradead.org> wrote:

> On Wed, 2010-11-03 at 21:34 -0700, Randy Dunlap wrote:
> > The build fails for me with the given .config file.
> > It's due to selects and depends, finally comes down to HAVE_PERF_EVENTS not being
> > enabled for M386 or M486.  Do you actually have a processor of that vintage?
> 
> FWIW this .config generates a _TON_ of Kconfig dep warnings..
> 
> Urgh, Kconfig hell.
> 
> config PERF_EVENTS
>         bool "Kernel performance events and counters"
>         default y if (PROFILING || PERF_COUNTERS)
>         depends on HAVE_PERF_EVENTS
>         select ANON_INODES
>         select IRQ_WORK
> 
> 
> # grep PERF_EVENTS borken-build/.config
> CONFIG_PERF_EVENTS=y
> CONFIG_HAVE_PERF_EVENTS_NMI=y
> 
> 
> 
> So we managed to get PERF_EVENTS=y even though its dependency
> HAVE_PERF_EVENTS=n.
> 
> 
> I bet that's because of:
> 
> config X86
>         select HAVE_PERF_EVENTS if (!M386 && !M486)
>         select PERF_EVENTS 
> 
> 
> Ingo, should we simply do something like the below patch?
> 
> ---
> Subject: x86: Remove M[34]86 conditional on HAVE_PERF_EVENTS
> 
> x86 requires PERF_EVENTS because of the hardware breakpoint mess,
> so don't make it conditional on M[34]86.
> 
> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
> ---
>  arch/x86/Kconfig |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index e832768..e330da2 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -21,7 +21,7 @@ config X86
>  	select HAVE_UNSTABLE_SCHED_CLOCK
>  	select HAVE_IDE
>  	select HAVE_OPROFILE
> -	select HAVE_PERF_EVENTS if (!M386 && !M486)
> +	select HAVE_PERF_EVENTS

Yeah, i guess that would be fine. Even an i386 has hw breakpoints.

Thanks,

	Ingo