diff --git a/src/arch/arm/aapcs64.hh b/src/arch/arm/aapcs64.hh
index 8a5e4374c5..fb7b8f8dfc 100644
--- a/src/arch/arm/aapcs64.hh
+++ b/src/arch/arm/aapcs64.hh
@@ -44,6 +44,8 @@ class ThreadContext;
 
 struct Aapcs64
 {
+    using UintPtr = uint64_t;
+
     struct State
     {
         int ngrn=0; // Next general purpose register number.
diff --git a/src/arch/arm/semihosting.hh b/src/arch/arm/semihosting.hh
index 74697f408a..7566887fc6 100644
--- a/src/arch/arm/semihosting.hh
+++ b/src/arch/arm/semihosting.hh
@@ -133,6 +133,8 @@ class ArmSemihosting : public SimObject
 
     struct Abi64 : public AbiBase
     {
+        using UintPtr = uint64_t;
+
         class State : public StateBase<uint64_t>
         {
           public:
@@ -145,6 +147,8 @@ class ArmSemihosting : public SimObject
 
     struct Abi32 : public AbiBase
     {
+        using UintPtr = uint32_t;
+
         class State : public StateBase<uint64_t>
         {
           public:
diff --git a/src/sim/proxy_ptr.hh b/src/sim/proxy_ptr.hh
index 02263bae45..968c1560cb 100644
--- a/src/sim/proxy_ptr.hh
+++ b/src/sim/proxy_ptr.hh
@@ -338,7 +338,8 @@ struct Argument<ABI, ProxyPtr<T, Proxy>>
     static ProxyPtr<T, Proxy>
     get(ThreadContext *tc, typename ABI::State &state)
     {
-        return ProxyPtr<T, Proxy>(Argument<ABI, Addr>::get(tc, state), tc);
+        return ProxyPtr<T, Proxy>(
+                Argument<ABI, typename ABI::UintPtr>::get(tc, state), tc);
     }
 };
 
@@ -349,7 +350,7 @@ struct Argument<ABI, ConstProxyPtr<T, Proxy>>
     get(ThreadContext *tc, typename ABI::State &state)
     {
         return ConstProxyPtr<T, Proxy>(
-                Argument<ABI, Addr>::get(tc, state), tc);
+                Argument<ABI, typename ABI::UintPtr>::get(tc, state), tc);
     }
 };
 
diff --git a/src/sim/proxy_ptr.test.cc b/src/sim/proxy_ptr.test.cc
index b9f46e6234..de0194d1b3 100644
--- a/src/sim/proxy_ptr.test.cc
+++ b/src/sim/proxy_ptr.test.cc
@@ -465,6 +465,7 @@ TEST(ProxyPtr, NonConstOperators)
 
 struct TestABI
 {
+    using UintPtr = uint64_t;
     using State = int;
 };
 
diff --git a/src/sim/syscall_abi.hh b/src/sim/syscall_abi.hh
index 984f0e0252..9d552028f8 100644
--- a/src/sim/syscall_abi.hh
+++ b/src/sim/syscall_abi.hh
@@ -54,10 +54,14 @@ struct GenericSyscallABI
 };
 
 struct GenericSyscallABI64 : public GenericSyscallABI
-{};
+{
+    using UintPtr = uint64_t;
+};
 
 struct GenericSyscallABI32 : public GenericSyscallABI
 {
+    using UintPtr = uint32_t;
+
     // Is this argument too big for a single register?
     template <typename T, typename Enabled=void>
     struct IsWide;
@@ -65,7 +69,7 @@ struct GenericSyscallABI32 : public GenericSyscallABI
     template <typename T>
     struct IsWide<T, typename std::enable_if_t<
         std::is_integral<T>::value &&
-        (sizeof(T) < sizeof(uint64_t) ||
+        (sizeof(T) <= sizeof(UintPtr) ||
          GuestABI::IsConforming<T>::value)>>
     {
         static const bool value = false;
@@ -74,7 +78,7 @@ struct GenericSyscallABI32 : public GenericSyscallABI
     template <typename T>
     struct IsWide<T, typename std::enable_if_t<
         std::is_integral<T>::value &&
-        sizeof(T) == sizeof(uint64_t) &&
+        (sizeof(T) > sizeof(UintPtr)) &&
         !GuestABI::IsConforming<T>::value>>
     {
         static const bool value = true;