perf, arch: Cleanup perf-pmu init vs lockup-detector

The perf hardware pmu got initialized at various points in the boot,
some before early_initcall() some after (notably arch_initcall).

The problem is that the NMI lockup detector is ran from early_initcall()
and expects the hardware pmu to be present.

Sanitize this by moving all architecture hardware pmu implementations to
initialize at early_initcall() and move the lockup detector to an explicit
initcall right after that.

Cc: paulus <paulus@samba.org>
Cc: davem <davem@davemloft.net>
Cc: Michael Cree <mcree@orcon.net.nz>
Cc: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1290707759.2145.119.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

3 files changed, 7 insertions, 7 deletions

diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index 550e26b1dbb3..d9d4dae305f6 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -125,7 +125,6 @@ union cpuid10_edx {
 #define IBS_OP_MAX_CNT_EXT      0x007FFFFFULL   /* not a register bit mask */
 
 #ifdef CONFIG_PERF_EVENTS
-extern void init_hw_perf_events(void);
 extern void perf_events_lapic_init(void);
 
 #define PERF_EVENT_INDEX_OFFSET                 0
@@ -156,7 +155,6 @@ extern unsigned long perf_misc_flags(struct pt_regs *regs);
 }
 
 #else
-static inline void init_hw_perf_events(void)            { }
 static inline void perf_events_lapic_init(void) { }
 #endif
 
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 4b68bda30938..1d59834396bd 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -894,7 +894,6 @@ void __init identify_boot_cpu(void)
 #else
         vgetcpu_set_mode();
 #endif
-        init_hw_perf_events();
 }
 
 void __cpuinit identify_secondary_cpu(struct cpuinfo_x86 *c)
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index c01dfec635db..817d2b195e8e 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1353,7 +1353,7 @@ static void __init pmu_check_apic(void)
         pr_info("no hardware sampling interrupt available.\n");
 }
 
-void __init init_hw_perf_events(void)
+int __init init_hw_perf_events(void)
 {
         struct event_constraint *c;
         int err;
@@ -1368,11 +1368,11 @@ void __init init_hw_perf_events(void)
                 err = amd_pmu_init();
                 break;
         default:
-                return;
+                return 0;
         }
         if (err != 0) {
                 pr_cont("no PMU driver, software events only.\n");
-                return;
+                return 0;
         }
 
         pmu_check_apic();
@@ -1380,7 +1380,7 @@ void __init init_hw_perf_events(void)
         /* sanity check that the hardware exists or is emulated */
         if (!check_hw_exists()) {
                 pr_cont("Broken PMU hardware detected, software events only.\n");
-                return;
+                return 0;
         }
 
         pr_cont("%s PMU driver.\n", x86_pmu.name);
@@ -1431,7 +1431,10 @@ void __init init_hw_perf_events(void)
 
         perf_pmu_register(&pmu);
         perf_cpu_notifier(x86_pmu_notifier);
+
+        return 0;
 }
+early_initcall(init_hw_perf_events);
 
 static inline void x86_pmu_read(struct perf_event *event)
 {