From 6f843a548408b283f60e4207e29daedd2d788110 Mon Sep 17 00:00:00 2001
From: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Date: Tue, 13 Feb 2018 14:50:12 -0500
Subject: [PATCH] arm: Implement uniprocessor with MP config

Add a boolean for indicating uniprocessors with MP extensions. This
drives the U bit in MPIDR. Prepares support for Cortex-R5.

Backports commit a8e81b319d1ae1224cc7059877dcdf04a5aad59d from qemu
---
 qemu/target-arm/cpu-qom.h | 3 +++
 qemu/target-arm/helper.c  | 6 ++++--
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/qemu/target-arm/cpu-qom.h b/qemu/target-arm/cpu-qom.h
index 5632fd56..9aedb6f6 100644
--- a/qemu/target-arm/cpu-qom.h
+++ b/qemu/target-arm/cpu-qom.h
@@ -115,6 +115,9 @@ typedef struct ARMCPU {
     /* KVM init features for this CPU */
     uint32_t kvm_init_features[7];
 
+    /* Uniprocessor system with MP extensions */
+    bool mp_is_up;
+
     /* The instance init functions for implementation-specific subclasses
      * set these fields to specify the implementation-dependent values of
      * various constant registers and reset values of non-constant
diff --git a/qemu/target-arm/helper.c b/qemu/target-arm/helper.c
index 951313ef..ea85b32f 100644
--- a/qemu/target-arm/helper.c
+++ b/qemu/target-arm/helper.c
@@ -1795,9 +1795,11 @@ static uint64_t mpidr_read(CPUARMState *env, const ARMCPRegInfo *ri)
         mpidr |= (1U << 31);
         /* Cores which are uniprocessor (non-coherent)
          * but still implement the MP extensions set
-         * bit 30. (For instance, A9UP.) However we do
-         * not currently model any of those cores.
+         * bit 30. (For instance, Cortex-R5).
          */
+        if (cpu->mp_is_up) {
+            mpidr |= (1u << 30);
+        }
     }
     return mpidr;
 }