From 5c167b8585c8d91206b395d57011ead7711e322f Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@elte.hu>
Date: Wed, 17 Dec 2008 09:02:19 +0100
Subject: x86, perfcounters: rename intel_arch_perfmon.h => perf_counter.h
Impact: rename include file
We'll be providing an asm/perf_counter.h to the generic perfcounter code,
so use the already existing x86 file for this purpose and rename it.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
arch/x86/oprofile/op_model_ppro.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
(limited to 'arch/x86/oprofile/op_model_ppro.c')
diff --git a/arch/x86/oprofile/op_model_ppro.c b/arch/x86/oprofile/op_model_ppro.c
index e9f80c744cf3..07c914555a5e 100644
--- a/arch/x86/oprofile/op_model_ppro.c
+++ b/arch/x86/oprofile/op_model_ppro.c
@@ -18,7 +18,7 @@
#include <asm/msr.h>
#include <asm/apic.h>
#include <asm/nmi.h>
-#include <asm/intel_arch_perfmon.h>
+#include <asm/perf_counter.h>
#include "op_x86_model.h"
#include "op_counter.h"
--
cgit v1.2.3
From 82aa9a1829199233f9bdaf26e2ee271114f4701e Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@elte.hu>
Date: Thu, 5 Feb 2009 15:23:08 +0100
Subject: perfcounters: fix "perf counters kills oprofile" bug, v2
Impact: fix kernel crash
Both oprofile and perfcounters register an NMI die handler, but only one
can handle the NMI. Conveniently, oprofile unregisters it's notifier
when not actively in use, so setting it's notifier priority higher than
perfcounter's allows oprofile to borrow the NMI for the duration of it's
run. Tested/works both as module and built-in.
While testing, I found that if kerneltop was generating NMIs at very
high frequency, the kernel may panic when oprofile registered it's
handler. This turned out to be because oprofile registers it's handler
before reset_value has been allocated, so if an NMI comes in while it's
still setting up, kabOom. Rather than try more invasive changes, I
followed the lead of other places in op_model_ppro.c, and simply
returned in that highly unlikely event. (debug warnings attached)
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
arch/x86/oprofile/op_model_ppro.c | 8 ++++++++
1 file changed, 8 insertions(+)
(limited to 'arch/x86/oprofile/op_model_ppro.c')
diff --git a/arch/x86/oprofile/op_model_ppro.c b/arch/x86/oprofile/op_model_ppro.c
index 07c914555a5e..85eb6268374f 100644
--- a/arch/x86/oprofile/op_model_ppro.c
+++ b/arch/x86/oprofile/op_model_ppro.c
@@ -126,6 +126,13 @@ static int ppro_check_ctrs(struct pt_regs * const regs,
u64 val;
int i;
+ /*
+ * This can happen if perf counters are in use when
+ * we steal the die notifier NMI.
+ */
+ if (unlikely(!reset_value))
+ goto out;
+
for (i = 0 ; i < num_counters; ++i) {
if (!reset_value[i])
continue;
@@ -136,6 +143,7 @@ static int ppro_check_ctrs(struct pt_regs * const regs,
}
}
+out:
/* Only P6 based Pentium M need to re-unmask the apic vector but it
* doesn't hurt other P6 variant */
apic_write(APIC_LVTPC, apic_read(APIC_LVTPC) & ~APIC_LVT_MASKED);
--
cgit v1.2.3