diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 0cff83e..ace5a43 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -1452,13 +1452,12 @@ static void do_debug_trap(struct cpu_user_regs *regs, unsigned int code)
 }
 #endif
 
+#define PSCI_SET_RESULT(reg, val) set_user_reg(reg, 0, val)
+#define PSCI_ARG(reg,n) get_user_reg(reg, n)
+
 #ifdef CONFIG_ARM_64
-#define PSCI_RESULT_REG(reg) (reg)->x0
-#define PSCI_ARG(reg,n) (reg)->x##n
-#define PSCI_ARG32(reg,n) (uint32_t)( (reg)->x##n & 0x00000000FFFFFFFF )
+#define PSCI_ARG32(reg,n) (uint32_t)get_user_reg(reg,n)
 #else
-#define PSCI_RESULT_REG(reg) (reg)->r0
-#define PSCI_ARG(reg,n) (reg)->r##n
 #define PSCI_ARG32(reg,n) PSCI_ARG(reg,n)
 #endif
 
@@ -1473,14 +1472,14 @@ static void do_trap_psci(struct cpu_user_regs *regs)
     uint32_t fid = PSCI_ARG32(regs,0);
 
     /* preloading in case psci_mode_check fails */
-    PSCI_RESULT_REG(regs) = PSCI_INVALID_PARAMETERS;
+    PSCI_SET_RESULT(regs, PSCI_INVALID_PARAMETERS);
     switch( fid )
     {
     case PSCI_cpu_off:
         {
             uint32_t pstate = PSCI_ARG32(regs,1);
             perfc_incr(vpsci_cpu_off);
-            PSCI_RESULT_REG(regs) = do_psci_cpu_off(pstate);
+            PSCI_SET_RESULT(regs, do_psci_cpu_off(pstate));
         }
         break;
     case PSCI_cpu_on:
@@ -1488,36 +1487,36 @@ static void do_trap_psci(struct cpu_user_regs *regs)
             uint32_t vcpuid = PSCI_ARG32(regs,1);
             register_t epoint = PSCI_ARG(regs,2);
             perfc_incr(vpsci_cpu_on);
-            PSCI_RESULT_REG(regs) = do_psci_cpu_on(vcpuid, epoint);
+            PSCI_SET_RESULT(regs, do_psci_cpu_on(vcpuid, epoint));
         }
         break;
     case PSCI_0_2_FN_PSCI_VERSION:
         perfc_incr(vpsci_version);
-        PSCI_RESULT_REG(regs) = do_psci_0_2_version();
+        PSCI_SET_RESULT(regs, do_psci_0_2_version());
         break;
     case PSCI_0_2_FN_CPU_OFF:
         perfc_incr(vpsci_cpu_off);
-        PSCI_RESULT_REG(regs) = do_psci_0_2_cpu_off();
+        PSCI_SET_RESULT(regs, do_psci_0_2_cpu_off());
         break;
     case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
         perfc_incr(vpsci_migrate_info_type);
-        PSCI_RESULT_REG(regs) = do_psci_0_2_migrate_info_type();
+        PSCI_SET_RESULT(regs, do_psci_0_2_migrate_info_type());
         break;
     case PSCI_0_2_FN_MIGRATE_INFO_UP_CPU:
     case PSCI_0_2_FN64_MIGRATE_INFO_UP_CPU:
         perfc_incr(vpsci_migrate_info_up_cpu);
         if ( psci_mode_check(current->domain, fid) )
-            PSCI_RESULT_REG(regs) = do_psci_0_2_migrate_info_up_cpu();
+            PSCI_SET_RESULT(regs, do_psci_0_2_migrate_info_up_cpu());
         break;
     case PSCI_0_2_FN_SYSTEM_OFF:
         perfc_incr(vpsci_system_off);
         do_psci_0_2_system_off();
-        PSCI_RESULT_REG(regs) = PSCI_INTERNAL_FAILURE;
+        PSCI_SET_RESULT(regs, PSCI_INTERNAL_FAILURE);
         break;
     case PSCI_0_2_FN_SYSTEM_RESET:
         perfc_incr(vpsci_system_reset);
         do_psci_0_2_system_reset();
-        PSCI_RESULT_REG(regs) = PSCI_INTERNAL_FAILURE;
+        PSCI_SET_RESULT(regs, PSCI_INTERNAL_FAILURE);
         break;
     case PSCI_0_2_FN_CPU_ON:
     case PSCI_0_2_FN64_CPU_ON:
@@ -1527,8 +1526,7 @@ static void do_trap_psci(struct cpu_user_regs *regs)
             register_t vcpuid = PSCI_ARG(regs,1);
             register_t epoint = PSCI_ARG(regs,2);
             register_t cid = PSCI_ARG(regs,3);
-            PSCI_RESULT_REG(regs) =
-                do_psci_0_2_cpu_on(vcpuid, epoint, cid);
+            PSCI_SET_RESULT(regs, do_psci_0_2_cpu_on(vcpuid, epoint, cid));
         }
         break;
     case PSCI_0_2_FN_CPU_SUSPEND:
@@ -1539,8 +1537,7 @@ static void do_trap_psci(struct cpu_user_regs *regs)
             uint32_t pstate = PSCI_ARG32(regs,1);
             register_t epoint = PSCI_ARG(regs,2);
             register_t cid = PSCI_ARG(regs,3);
-            PSCI_RESULT_REG(regs) =
-                do_psci_0_2_cpu_suspend(pstate, epoint, cid);
+            PSCI_SET_RESULT(regs, do_psci_0_2_cpu_suspend(pstate, epoint, cid));
         }
         break;
     case PSCI_0_2_FN_AFFINITY_INFO:
@@ -1550,8 +1547,7 @@ static void do_trap_psci(struct cpu_user_regs *regs)
         {
             register_t taff = PSCI_ARG(regs,1);
             uint32_t laff = PSCI_ARG32(regs,2);
-            PSCI_RESULT_REG(regs) =
-                do_psci_0_2_affinity_info(taff, laff);
+            PSCI_SET_RESULT(regs, do_psci_0_2_affinity_info(taff, laff));
         }
         break;
     case PSCI_0_2_FN_MIGRATE:
@@ -1560,7 +1556,7 @@ static void do_trap_psci(struct cpu_user_regs *regs)
         if ( psci_mode_check(current->domain, fid) )
         {
             uint32_t tcpu = PSCI_ARG32(regs,1);
-            PSCI_RESULT_REG(regs) = do_psci_0_2_migrate(tcpu);
+            PSCI_SET_RESULT(regs, do_psci_0_2_migrate(tcpu));
         }
         break;
     default:
