[PATCH] ARMv7: fix Oprofile events count
Jean Pihet
jpihet at mvista.com
Mon Dec 14 06:40:11 EST 2009
Hi,
Here is a patch that fixes the oprofile events count.
If it is OK I will submit it to the patch system.
Any thought?
Regards,
Jean
---
ARMv7: fix Oprofile events count
On Oprofile ARMv7 the PMNC_D bit was set to lower the PMU IRQs
and so to decrease the risk of errata #628216 from appearing.
The effect of setting the PMNC_D bit is that the CCNT counter
is divided by 64, making the program counter events count
inaccurate.
The new OMAP3 r4 cores should have that errata fixed.
The PMNC_D bit should not be set, this patch fixes it.
Signed-off-by: Jean Pihet <jpihet at mvista.com>
diff --git a/arch/arm/oprofile/op_model_v7.c
b/arch/arm/oprofile/op_model_v7.c
index f20295f..2088a6c 100644
--- a/arch/arm/oprofile/op_model_v7.c
+++ b/arch/arm/oprofile/op_model_v7.c
@@ -191,12 +191,8 @@ int armv7_setup_pmnc(void)
return -EBUSY;
}
- /*
- * Initialize & Reset PMNC: C bit, D bit and P bit.
- * Note: Using a slower count for CCNT (D bit: divide by 64)
results
- * in a more stable system
- */
- armv7_pmnc_write(PMNC_P | PMNC_C | PMNC_D);
+ /* Initialize & Reset PMNC: C bit and P bit */
+ armv7_pmnc_write(PMNC_P | PMNC_C);
for (cnt = CCNT; cnt < CNTMAX; cnt++) {
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