diff --git a/include/exec/user/abitypes.h b/include/exec/user/abitypes.h
index a09d6c64ff7c..ba188608c2da 100644
--- a/include/exec/user/abitypes.h
+++ b/include/exec/user/abitypes.h
@@ -15,6 +15,10 @@
 #define ABI_LLONG_ALIGNMENT 2
 #endif
 
+#if defined(TARGET_I386) && !defined(TARGET_X86_64)
+#define ABI_LLONG_ALIGNMENT 4
+#endif
+
 #ifndef ABI_SHORT_ALIGNMENT
 #define ABI_SHORT_ALIGNMENT 2
 #endif
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index ca6a2b495a80..833f853200e2 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -839,7 +839,7 @@ void target_set_brk(abi_ulong new_brk)
 abi_long do_brk(abi_ulong new_brk)
 {
     abi_long mapped_addr;
-    int	new_alloc_size;
+    abi_ulong new_alloc_size;
 
     DEBUGF_BRK("do_brk(" TARGET_ABI_FMT_lx ") -> ", new_brk);
 
@@ -3754,27 +3754,30 @@ static struct shm_region {
     bool in_use;
 } shm_regions[N_SHM_REGIONS];
 
-struct target_semid_ds
+#ifndef TARGET_SEMID64_DS
+/* asm-generic version of this struct */
+struct target_semid64_ds
 {
   struct target_ipc_perm sem_perm;
   abi_ulong sem_otime;
-#if !defined(TARGET_PPC64)
+#if TARGET_ABI_BITS == 32
   abi_ulong __unused1;
 #endif
   abi_ulong sem_ctime;
-#if !defined(TARGET_PPC64)
+#if TARGET_ABI_BITS == 32
   abi_ulong __unused2;
 #endif
   abi_ulong sem_nsems;
   abi_ulong __unused3;
   abi_ulong __unused4;
 };
+#endif
 
 static inline abi_long target_to_host_ipc_perm(struct ipc_perm *host_ip,
                                                abi_ulong target_addr)
 {
     struct target_ipc_perm *target_ip;
-    struct target_semid_ds *target_sd;
+    struct target_semid64_ds *target_sd;
 
     if (!lock_user_struct(VERIFY_READ, target_sd, target_addr, 1))
         return -TARGET_EFAULT;
@@ -3802,7 +3805,7 @@ static inline abi_long host_to_target_ipc_perm(abi_ulong target_addr,
                                                struct ipc_perm *host_ip)
 {
     struct target_ipc_perm *target_ip;
-    struct target_semid_ds *target_sd;
+    struct target_semid64_ds *target_sd;
 
     if (!lock_user_struct(VERIFY_WRITE, target_sd, target_addr, 0))
         return -TARGET_EFAULT;
@@ -3829,7 +3832,7 @@ static inline abi_long host_to_target_ipc_perm(abi_ulong target_addr,
 static inline abi_long target_to_host_semid_ds(struct semid_ds *host_sd,
                                                abi_ulong target_addr)
 {
-    struct target_semid_ds *target_sd;
+    struct target_semid64_ds *target_sd;
 
     if (!lock_user_struct(VERIFY_READ, target_sd, target_addr, 1))
         return -TARGET_EFAULT;
@@ -3845,7 +3848,7 @@ static inline abi_long target_to_host_semid_ds(struct semid_ds *host_sd,
 static inline abi_long host_to_target_semid_ds(abi_ulong target_addr,
                                                struct semid_ds *host_sd)
 {
-    struct target_semid_ds *target_sd;
+    struct target_semid64_ds *target_sd;
 
     if (!lock_user_struct(VERIFY_WRITE, target_sd, target_addr, 0))
         return -TARGET_EFAULT;
@@ -6856,7 +6859,7 @@ static int open_self_cmdline(void *cpu_env, int fd)
         if (!word_skipped) {
             /* Skip the first string, which is the path to qemu-*-static
                instead of the actual command. */
-            cp_buf = memchr(buf, 0, sizeof(buf));
+            cp_buf = memchr(buf, 0, nb_read);
             if (cp_buf) {
                 /* Null byte found, skip one string */
                 cp_buf++;
@@ -9237,12 +9240,14 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
                 goto efault;
             ret = get_errno(sys_uname(buf));
             if (!is_error(ret)) {
-                /* Overrite the native machine name with whatever is being
+                /* Overwrite the native machine name with whatever is being
                    emulated. */
                 strcpy (buf->machine, cpu_to_uname_machine(cpu_env));
                 /* Allow the user to override the reported release.  */
-                if (qemu_uname_release && *qemu_uname_release)
-                  strcpy (buf->release, qemu_uname_release);
+                if (qemu_uname_release && *qemu_uname_release) {
+                    g_strlcpy(buf->release, qemu_uname_release,
+                              sizeof(buf->release));
+                }
             }
             unlock_user_struct(buf, arg1, 1);
         }
diff --git a/linux-user/x86_64/target_structs.h b/linux-user/x86_64/target_structs.h
index 348982703ea7..b6e82a822cb8 100644
--- a/linux-user/x86_64/target_structs.h
+++ b/linux-user/x86_64/target_structs.h
@@ -55,4 +55,19 @@ struct target_shmid_ds {
     abi_ulong __unused5;
 };
 
+/* The x86 definition differs from the generic one in that the
+ * two padding fields exist whether the ABI is 32 bits or 64 bits.
+ */
+#define TARGET_SEMID64_DS
+struct target_semid64_ds {
+    struct target_ipc_perm sem_perm;
+    abi_ulong sem_otime;
+    abi_ulong __unused1;
+    abi_ulong sem_ctime;
+    abi_ulong __unused2;
+    abi_ulong sem_nsems;
+    abi_ulong __unused3;
+    abi_ulong __unused4;
+};
+
 #endif