diff --git a/linux-user/alpha/target_signal.h b/linux-user/alpha/target_signal.h
index 0b90d3a897..250642913e 100644
--- a/linux-user/alpha/target_signal.h
+++ b/linux-user/alpha/target_signal.h
@@ -92,6 +92,7 @@ typedef struct target_sigaltstack {
 #define TARGET_GEN_SUBRNG7     -25
 
 #define TARGET_ARCH_HAS_SETUP_FRAME
+#define TARGET_ARCH_HAS_KA_RESTORER
 
 /* bit-flags */
 #define TARGET_SS_AUTODISARM (1U << 31) /* disable sas during sighandling */
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index a2e18b06c6..048056ba2b 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -9064,41 +9064,17 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
 #endif
     case TARGET_NR_rt_sigaction:
         {
-#if defined(TARGET_ALPHA)
-            /* For Alpha and SPARC this is a 5 argument syscall, with
+            /*
+             * For Alpha and SPARC this is a 5 argument syscall, with
              * a 'restorer' parameter which must be copied into the
              * sa_restorer field of the sigaction struct.
              * For Alpha that 'restorer' is arg5; for SPARC it is arg4,
              * and arg5 is the sigsetsize.
-             * Alpha also has a separate rt_sigaction struct that it uses
-             * here; SPARC uses the usual sigaction struct.
              */
-            struct target_rt_sigaction *rt_act;
-            struct target_sigaction act, oact, *pact = 0;
-
-            if (arg4 != sizeof(target_sigset_t)) {
-                return -TARGET_EINVAL;
-            }
-            if (arg2) {
-                if (!lock_user_struct(VERIFY_READ, rt_act, arg2, 1))
-                    return -TARGET_EFAULT;
-                act._sa_handler = rt_act->_sa_handler;
-                act.sa_mask = rt_act->sa_mask;
-                act.sa_flags = rt_act->sa_flags;
-                unlock_user_struct(rt_act, arg2, 0);
-                pact = &act;
-            }
-            ret = get_errno(do_sigaction(arg1, pact, &oact, arg5));
-            if (!is_error(ret) && arg3) {
-                if (!lock_user_struct(VERIFY_WRITE, rt_act, arg3, 0))
-                    return -TARGET_EFAULT;
-                rt_act->_sa_handler = oact._sa_handler;
-                rt_act->sa_mask = oact.sa_mask;
-                rt_act->sa_flags = oact.sa_flags;
-                unlock_user_struct(rt_act, arg3, 1);
-            }
-#else
-#ifdef TARGET_SPARC
+#if defined(TARGET_ALPHA)
+            target_ulong sigsetsize = arg4;
+            target_ulong restorer = arg5;
+#elif defined(TARGET_SPARC)
             target_ulong restorer = arg4;
             target_ulong sigsetsize = arg5;
 #else
@@ -9131,7 +9107,6 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
                 unlock_user_struct(act, arg2, 0);
             if (oact)
                 unlock_user_struct(oact, arg3, 1);
-#endif
         }
         return ret;
 #ifdef TARGET_NR_sgetmask /* not on alpha */
diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
index e4aaf8412f..7a1d3b239c 100644
--- a/linux-user/syscall_defs.h
+++ b/linux-user/syscall_defs.h
@@ -507,12 +507,6 @@ struct target_old_sigaction {
     int32_t sa_flags;
 };
 
-struct target_rt_sigaction {
-    abi_ulong _sa_handler;
-    abi_ulong sa_flags;
-    target_sigset_t sa_mask;
-};
-
 /* This is the struct used inside the kernel.  The ka_restorer
    field comes from the 5th argument to sys_rt_sigaction.  */
 struct target_sigaction {