From 726c7b545fed8bc842a40c5cbdb424bdf38c2cc3 Mon Sep 17 00:00:00 2001
From: Vincenzo Frascino <vincenzo.frascino@linaro.org>
Date: Wed, 29 Mar 2017 11:29:26 +0100
Subject: [PATCH] arm: core: mpu: Add core MPU implementation

This patch adds the arm core MPU implementation.
This implementation currently supports the thread stack guard feature.

Change-Id: I8b3795ebaf1ebad38aaddc2ed2f05535ead2c09a
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@linaro.org>
---
 arch/arm/core/cortex_m/mpu/Makefile       |  1 +
 arch/arm/core/cortex_m/mpu/arm_core_mpu.c | 31 +++++++++++++++++++++++
 2 files changed, 32 insertions(+)
 create mode 100644 arch/arm/core/cortex_m/mpu/arm_core_mpu.c

diff --git a/arch/arm/core/cortex_m/mpu/Makefile b/arch/arm/core/cortex_m/mpu/Makefile
index 69556bc0147..b01b5de495f 100644
--- a/arch/arm/core/cortex_m/mpu/Makefile
+++ b/arch/arm/core/cortex_m/mpu/Makefile
@@ -1,2 +1,3 @@
+obj-$(CONFIG_ARM_CORE_MPU) += arm_core_mpu.o
 obj-$(CONFIG_ARM_MPU) += arm_mpu.o
 obj-$(CONFIG_NXP_MPU) += nxp_mpu.o
diff --git a/arch/arm/core/cortex_m/mpu/arm_core_mpu.c b/arch/arm/core/cortex_m/mpu/arm_core_mpu.c
new file mode 100644
index 00000000000..932ef77734b
--- /dev/null
+++ b/arch/arm/core/cortex_m/mpu/arm_core_mpu.c
@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2017 Linaro Limited.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <device.h>
+#include <init.h>
+#include <kernel.h>
+#include <soc.h>
+#include <arch/arm/cortex_m/cmsis.h>
+#include <arch/arm/cortex_m/mpu/arm_core_mpu.h>
+
+#if defined(CONFIG_MPU_STACK_GUARD)
+/*
+ * @brief Configure MPU stack guard
+ *
+ * This function configures per thread stack guards reprogramming the MPU.
+ * The functionality is meant to be used during context switch.
+ *
+ * @param thread thread info data structure.
+ */
+void configure_mpu_stack_guard(struct k_thread *thread)
+{
+	arm_core_mpu_disable();
+	arm_core_mpu_configure(THREAD_STACK_GUARD_REGION,
+			       thread->stack_info.start,
+			       thread->stack_info.size);
+	arm_core_mpu_enable();
+}
+#endif