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From 47cb7627876fdc6a6b90eb86dc77705a6df0072a Mon Sep 17 00:00:00 2001
From: Mans Rullgard <mans@mansr.com>
Date: Tue, 10 Nov 2009 00:52:56 +0000
Subject: [PATCH 6/8] ARM: Add option to allow userspace access to performance counters
This adds an option to allow userspace access to the performance monitor
registers of the Cortex-A8.
Signed-off-by: Mans Rullgard <mans@mansr.com>
---
arch/arm/mm/Kconfig | 7 +++++++
arch/arm/mm/proc-v7.S | 6 ++++++
2 files changed, 13 insertions(+), 0 deletions(-)
diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig
index 4a337ab..a49ff8b 100644
--- a/arch/arm/mm/Kconfig
+++ b/arch/arm/mm/Kconfig
@@ -861,3 +861,10 @@ config USER_L2_PLE
help
Enable userspace access to the L2 preload engine (PLE) available
in Cortex-A series ARM processors.
+
+config USER_PMON
+ bool "Enable userspace access to performance counters"
+ depends on CPU_V7
+ default n
+ help
+ Enable userpsace access to the performance monitor registers.
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index c1c3fe0..bd10c28 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -276,6 +276,12 @@ __v7_setup:
mcr p15, 0, r5, c10, c2, 0 @ write PRRR
mcr p15, 0, r6, c10, c2, 1 @ write NMRR
#endif
+
+#ifdef CONFIG_USER_PMON
+ mov r0, #1
+ mcr p15, 0, r0, c9, c14, 0
+#endif
+
adr r5, v7_crval
ldmia r5, {r5, r6}
#ifdef CONFIG_CPU_ENDIAN_BE8
--
1.6.6.1
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