From 0299851aa06d4046cb95ceb992f268c4c6381443 Mon Sep 17 00:00:00 2001
From: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Date: Tue, 13 Feb 2018 14:52:38 -0500
Subject: [PATCH] arm: Add has-mpu property

For processors that support MPUs, add a property to de-feature it. This
is similar to the implementation of the EL3 feature.

The processor definition in init sets ARM_FEATURE_MPU if it can support
an MPU. post_init exposes the property, defaulting to true. If cleared
by the instantiator, ARM_FEATURE_MPU is then removed at realize time.

This is to support R profile processors that may or may-not have an MPU
configured.

Backports commit 8f325f568fbd0158cd413e7d637573ba90b3eaab from qemu
---
 qemu/target-arm/cpu-qom.h | 3 +++
 qemu/target-arm/cpu.c     | 4 ++++
 2 files changed, 7 insertions(+)

diff --git a/qemu/target-arm/cpu-qom.h b/qemu/target-arm/cpu-qom.h
index 9aedb6f6..420b3ab4 100644
--- a/qemu/target-arm/cpu-qom.h
+++ b/qemu/target-arm/cpu-qom.h
@@ -102,6 +102,9 @@ typedef struct ARMCPU {
     /* CPU has security extension */
     bool has_el3;
 
+    /* CPU has memory protection unit */
+    bool has_mpu;
+
     /* PSCI conduit used to invoke PSCI methods
      * 0 - disabled, 1 - smc, 2 - hvc
      */
diff --git a/qemu/target-arm/cpu.c b/qemu/target-arm/cpu.c
index 01c160ad..bd771a59 100644
--- a/qemu/target-arm/cpu.c
+++ b/qemu/target-arm/cpu.c
@@ -485,6 +485,10 @@ static int arm_cpu_realizefn(struct uc_struct *uc, DeviceState *dev, Error **err
         cpu->id_aa64pfr0 &= ~0xf000;
     }
 
+    if (!cpu->has_mpu) {
+        unset_feature(env, ARM_FEATURE_MPU);
+    }
+
     if (arm_feature(env, ARM_FEATURE_EL3)) {
         set_feature(env, ARM_FEATURE_VBAR);
     }