diff --git a/target/arm/arm-semi.c b/target/arm/arm-semi.c
index 03e60105c0..51b55816fa 100644
--- a/target/arm/arm-semi.c
+++ b/target/arm/arm-semi.c
@@ -232,11 +232,13 @@ static target_ulong arm_gdb_syscall(ARMCPU *cpu, gdb_syscall_complete_cb cb,
 #define GET_ARG(n) do {                                 \
     if (is_a64(env)) {                                  \
         if (get_user_u64(arg ## n, args + (n) * 8)) {   \
-            return -1;                                  \
+            errno = EFAULT;                             \
+            return set_swi_errno(ts, -1);               \
         }                                               \
     } else {                                            \
         if (get_user_u32(arg ## n, args + (n) * 4)) {   \
-            return -1;                                  \
+            errno = EFAULT;                             \
+            return set_swi_errno(ts, -1);               \
         }                                               \
     }                                                   \
 } while (0)
@@ -287,12 +289,13 @@ target_ulong do_arm_semihosting(CPUARMState *env)
         GET_ARG(2);
         s = lock_user_string(arg0);
         if (!s) {
-            /* FIXME - should this error code be -TARGET_EFAULT ? */
-            return (uint32_t)-1;
+            errno = EFAULT;
+            return set_swi_errno(ts, -1);
         }
         if (arg1 >= 12) {
             unlock_user(s, arg0, 0);
-            return (uint32_t)-1;
+            errno = EINVAL;
+            return set_swi_errno(ts, -1);
         }
         if (strcmp(s, ":tt") == 0) {
             int result_fileno = arg1 < 4 ? STDIN_FILENO : STDOUT_FILENO;
@@ -413,8 +416,8 @@ target_ulong do_arm_semihosting(CPUARMState *env)
         } else {
             s = lock_user_string(arg0);
             if (!s) {
-                /* FIXME - should this error code be -TARGET_EFAULT ? */
-                return (uint32_t)-1;
+                errno = EFAULT;
+                return set_swi_errno(ts, -1);
             }
             ret =  set_swi_errno(ts, remove(s));
             unlock_user(s, arg0, 0);
@@ -432,11 +435,12 @@ target_ulong do_arm_semihosting(CPUARMState *env)
             char *s2;
             s = lock_user_string(arg0);
             s2 = lock_user_string(arg2);
-            if (!s || !s2)
-                /* FIXME - should this error code be -TARGET_EFAULT ? */
-                ret = (uint32_t)-1;
-            else
+            if (!s || !s2) {
+                errno = EFAULT;
+                ret = set_swi_errno(ts, -1);
+            } else {
                 ret = set_swi_errno(ts, rename(s, s2));
+            }
             if (s2)
                 unlock_user(s2, arg2, 0);
             if (s)
@@ -456,8 +460,8 @@ target_ulong do_arm_semihosting(CPUARMState *env)
         } else {
             s = lock_user_string(arg0);
             if (!s) {
-                /* FIXME - should this error code be -TARGET_EFAULT ? */
-                return (uint32_t)-1;
+                errno = EFAULT;
+                return set_swi_errno(ts, -1);
             }
             ret = set_swi_errno(ts, system(s));
             unlock_user(s, arg0, 0);
@@ -517,19 +521,22 @@ target_ulong do_arm_semihosting(CPUARMState *env)
 
             if (output_size > input_size) {
                 /* Not enough space to store command-line arguments.  */
-                return -1;
+                errno = E2BIG;
+                return set_swi_errno(ts, -1);
             }
 
             /* Adjust the command-line length.  */
             if (SET_ARG(1, output_size - 1)) {
                 /* Couldn't write back to argument block */
-                return -1;
+                errno = EFAULT;
+                return set_swi_errno(ts, -1);
             }
 
             /* Lock the buffer on the ARM side.  */
             output_buffer = lock_user(VERIFY_WRITE, arg0, output_size, 0);
             if (!output_buffer) {
-                return -1;
+                errno = EFAULT;
+                return set_swi_errno(ts, -1);
             }
 
             /* Copy the command-line arguments.  */
@@ -544,7 +551,8 @@ target_ulong do_arm_semihosting(CPUARMState *env)
 
             if (copy_from_user(output_buffer, ts->info->arg_start,
                                output_size)) {
-                status = -1;
+                errno = EFAULT;
+                status = set_swi_errno(ts, -1);
                 goto out;
             }
 
@@ -614,7 +622,8 @@ target_ulong do_arm_semihosting(CPUARMState *env)
 
                 if (fail) {
                     /* Couldn't write back to argument block */
-                    return -1;
+                    errno = EFAULT;
+                    return set_swi_errno(ts, -1);
                 }
             }
             return 0;