Re: 2.6.37-rc1 build failure
From: Ingo Molnar
Date: Wed Nov 10 2010 - 08:24:40 EST
* Peter Zijlstra <peterz@xxxxxxxxxxxxx> 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@xxxxxxxxx>
> ---
> 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
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