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

