From 465f7d0f56fe47ad5070cc7fcc69bf69cb7d3d82 Mon Sep 17 00:00:00 2001
From: Adrian Herrera <adrian.herrera@arm.com>
Date: Wed, 6 Nov 2019 13:00:21 +0000
Subject: arch-arm: reg access permissions highest EL helper

This patch implements a helper function to filter a register access
permissions by the highest EL implemented by the system.
This filtering is convenient to follow the architecture pseudocode.

Change-Id: Iedfb2d8624c926f2f0a9326f8b1b073ea9424ab9
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/24663
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
---
 src/arch/arm/isa.cc | 14 +++++++++++++-
 src/arch/arm/isa.hh |  3 ++-
 2 files changed, 15 insertions(+), 2 deletions(-)

(limited to 'src')

diff --git a/src/arch/arm/isa.cc b/src/arch/arm/isa.cc
index 767fd9f6a..101ca5420 100644
--- a/src/arch/arm/isa.cc
+++ b/src/arch/arm/isa.cc
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010-2019 ARM Limited
+ * Copyright (c) 2010-2020 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -2190,6 +2190,18 @@ ISA::zeroSveVecRegUpperPart(VecRegContainer &vc, unsigned eCount)
     }
 }
 
+ISA::MiscRegLUTEntryInitializer::chain
+ISA::MiscRegLUTEntryInitializer::highest(ArmSystem *const sys) const
+{
+    switch (FullSystem ? sys->highestEL() : EL1) {
+      case EL0:
+      case EL1: priv(); break;
+      case EL2: hyp(); break;
+      case EL3: mon(); break;
+    }
+    return *this;
+}
+
 }  // namespace ArmISA
 
 ArmISA::ISA *
diff --git a/src/arch/arm/isa.hh b/src/arch/arm/isa.hh
index fea372ed4..7ffa682ef 100644
--- a/src/arch/arm/isa.hh
+++ b/src/arch/arm/isa.hh
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, 2012-2019 ARM Limited
+ * Copyright (c) 2010, 2012-2020 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -357,6 +357,7 @@ namespace ArmISA
                 user(0);
                 return *this;
             }
+            chain highest(ArmSystem *const sys) const;
             MiscRegLUTEntryInitializer(struct MiscRegLUTEntry &e,
                                        std::bitset<NUM_MISCREG_INFOS> &i)
               : entry(e),
-- 
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