From 8576e1971663ffdb6139041de97cdd2e1d4791cc Mon Sep 17 00:00:00 2001 From: Cyrill Gorcunov Date: Sat, 13 Mar 2010 11:11:16 +0300 Subject: [PATCH] x86, perf: Unmask LVTPC only if we have APIC supported Ingo reported: | | There's a build failure on -tip with the P4 driver, on UP 32-bit, if | PERF_EVENTS is enabled but UP_APIC is disabled: | | arch/x86/built-in.o: In function `p4_pmu_handle_irq': | perf_event.c:(.text+0xa756): undefined reference to `apic' | perf_event.c:(.text+0xa76e): undefined reference to `apic' | So we have to unmask LVTPC only if we're configured to have one. Reported-by: Ingo Molnar Signed-off-by: Cyrill Gorcunov CC: Lin Ming CC: Peter Zijlstra LKML-Reference: <20100313081116.GA5179@lenovo> Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_event_p4.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kernel/cpu/perf_event_p4.c b/arch/x86/kernel/cpu/perf_event_p4.c index 381f593e8297..ef861da1c8ab 100644 --- a/arch/x86/kernel/cpu/perf_event_p4.c +++ b/arch/x86/kernel/cpu/perf_event_p4.c @@ -365,8 +365,10 @@ static int p4_pmu_handle_irq(struct pt_regs *regs) } if (handled) { +#ifdef CONFIG_X86_LOCAL_APIC /* p4 quirk: unmask it again */ apic_write(APIC_LVTPC, apic_read(APIC_LVTPC) & ~APIC_LVT_MASKED); +#endif inc_irq_stat(apic_perf_irqs); }