configure: Make NPTL non-optional

Now all linux-user targets support building with NPTL, we can make it
mandatory. This is a good idea because:
 * NPTL is no longer new and experimental; it is completely standard
 * in practice, linux-user without NPTL is nearly useless for
   binaries built against non-ancient glibc
 * it allows us to delete the rather untested code for handling
   the non-NPTL configuration

Note that this patch leaves the CONFIG_USE_NPTL ifdefs in the
bsd-user codebase alone. This makes no change for bsd-user, since
our configure test for NPTL had a "#include <linux/futex.h>"
which means bsd-user would never have been compiled with
CONFIG_USE_NPTL defined, and it still is not.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>

configure

@@ -155,7 +155,6 @@ curl=""
 curses=""
 docs=""
 fdt=""
-nptl=""
 pixman=""
 sdl=""
 virtfs=""
@@ -855,10 +854,6 @@ for opt do
   ;;
   --enable-fdt) fdt="yes"
   ;;
-  --disable-nptl) nptl="no"
-  ;;
-  --enable-nptl) nptl="yes"
-  ;;
   --enable-mixemu) mixemu="yes"
   ;;
   --disable-linux-aio) linux_aio="no"
@@ -1096,8 +1091,6 @@ echo "  --disable-slirp          disable SLIRP userspace network connectivity"
 echo "  --disable-kvm            disable KVM acceleration support"
 echo "  --enable-kvm             enable KVM acceleration support"
 echo "  --enable-tcg-interpreter enable TCG with bytecode interpreter (TCI)"
-echo "  --disable-nptl           disable usermode NPTL support"
-echo "  --enable-nptl            enable usermode NPTL support"
 echo "  --enable-system          enable all system emulation targets"
 echo "  --disable-system         disable all system emulation targets"
 echo "  --enable-user            enable supported user emulation targets"
@@ -1432,7 +1425,7 @@ fi
 ##########################################
 # NPTL probe
 
-if test "$nptl" != "no" ; then
+if test "$linux_user" = "yes"; then
   cat > $TMPC <<EOF
 #include <sched.h>
 #include <linux/futex.h>
@@ -1443,14 +1436,8 @@ int main(void) {
   return 0;
 }
 EOF
-
-  if compile_object ; then
-    nptl=yes
-  else
-    if test "$nptl" = "yes" ; then
-      feature_not_found "nptl"
-    fi
-    nptl=no
+  if ! compile_object ; then
+    feature_not_found "nptl"
   fi
 fi
 
@@ -3550,7 +3537,6 @@ echo "bluez  support    $bluez"
 echo "Documentation     $docs"
 [ ! -z "$uname_release" ] && \
 echo "uname -r          $uname_release"
-echo "NPTL support      $nptl"
 echo "GUEST_BASE        $guest_base"
 echo "PIE               $pie"
 echo "vde support       $vde"
@@ -4180,7 +4166,6 @@ mkdir -p $target_dir
 echo "# Automatically generated by configure - do not modify" > $config_target_mak
 
 bflt="no"
-target_nptl="yes"
 interp_prefix1=`echo "$interp_prefix" | sed "s/%M/$target_name/g"`
 gdb_xml_files=""
 
@@ -4351,10 +4336,6 @@ fi
 if test "$target_user_only" = "yes" -a "$bflt" = "yes"; then
   echo "TARGET_HAS_BFLT=y" >> $config_target_mak
 fi
-if test "$target_user_only" = "yes" \
-        -a "$nptl" = "yes" -a "$target_nptl" = "yes"; then
-  echo "CONFIG_USE_NPTL=y" >> $config_target_mak
-fi
 if test "$target_user_only" = "yes" -a "$guest_base" = "yes"; then
   echo "CONFIG_USE_GUEST_BASE=y" >> $config_target_mak
 fi

include/exec/gdbstub.h

@@ -32,7 +32,7 @@ void gdb_register_coprocessor(CPUArchState *env,
 
 static inline int cpu_index(CPUState *cpu)
 {
-#if defined(CONFIG_USER_ONLY) && defined(CONFIG_USE_NPTL)
+#if defined(CONFIG_USER_ONLY)
     return cpu->host_tid;
 #else
     return cpu->cpu_index + 1;

linux-user/main.c

@@ -92,7 +92,6 @@ int cpu_get_pic_interrupt(CPUX86State *env)
 }
 #endif
 
-#if defined(CONFIG_USE_NPTL)
 /***********************************************************/
 /* Helper routines for implementing atomic operations.  */
 
@@ -207,43 +206,6 @@ void cpu_list_unlock(void)
 {
     pthread_mutex_unlock(&cpu_list_mutex);
 }
-#else /* if !CONFIG_USE_NPTL */
-/* These are no-ops because we are not threadsafe.  */
-static inline void cpu_exec_start(CPUState *cpu)
-{
-}
-
-static inline void cpu_exec_end(CPUState *cpu)
-{
-}
-
-static inline void start_exclusive(void)
-{
-}
-
-static inline void end_exclusive(void)
-{
-}
-
-void fork_start(void)
-{
-}
-
-void fork_end(int child)
-{
-    if (child) {
-        gdbserver_fork((CPUArchState *)thread_cpu->env_ptr);
-    }
-}
-
-void cpu_list_lock(void)
-{
-}
-
-void cpu_list_unlock(void)
-{
-}
-#endif
 
 
 #ifdef TARGET_I386
@@ -3156,12 +3118,7 @@ THREAD CPUState *thread_cpu;
 void task_settid(TaskState *ts)
 {
     if (ts->ts_tid == 0) {
-#ifdef CONFIG_USE_NPTL
         ts->ts_tid = (pid_t)syscall(SYS_gettid);
-#else
-        /* when no threads are used, tid becomes pid */
-        ts->ts_tid = getpid();
-#endif
     }
 }
 

linux-user/mmap.c

@@ -33,7 +33,6 @@
 
 //#define DEBUG_MMAP
 
-#if defined(CONFIG_USE_NPTL)
 static pthread_mutex_t mmap_mutex = PTHREAD_MUTEX_INITIALIZER;
 static __thread int mmap_lock_count;
 
@@ -66,16 +65,6 @@ void mmap_fork_end(int child)
     else
         pthread_mutex_unlock(&mmap_mutex);
 }
-#else
-/* We aren't threadsafe to start with, so no need to worry about locking.  */
-void mmap_lock(void)
-{
-}
-
-void mmap_unlock(void)
-{
-}
-#endif
 
 /* NOTE: all the constants are the HOST ones, but addresses are target. */
 int target_mprotect(abi_ulong start, abi_ulong len, int prot)

linux-user/qemu.h

@@ -19,11 +19,7 @@
 #include "exec/gdbstub.h"
 #include "qemu/queue.h"
 
-#if defined(CONFIG_USE_NPTL)
 #define THREAD __thread
-#else
-#define THREAD
-#endif
 
 /* This struct is used to hold certain information about the image.
  * Basically, it replicates in user space what would be certain
@@ -116,9 +112,7 @@ typedef struct TaskState {
     uint32_t v86flags;
     uint32_t v86mask;
 #endif
-#ifdef CONFIG_USE_NPTL
     abi_ulong child_tidptr;
-#endif
 #ifdef TARGET_M68K
     int sim_syscalls;
     abi_ulong tp_value;
@@ -268,10 +262,8 @@ void mmap_unlock(void);
 abi_ulong mmap_find_vma(abi_ulong, abi_ulong);
 void cpu_list_lock(void);
 void cpu_list_unlock(void);
-#if defined(CONFIG_USE_NPTL)
 void mmap_fork_start(void);
 void mmap_fork_end(int child);
-#endif
 
 /* main.c */
 extern unsigned long guest_stack_size;
@@ -449,9 +441,7 @@ static inline void *lock_user_string(abi_ulong guest_addr)
 #define unlock_user_struct(host_ptr, guest_addr, copy)		\
     unlock_user(host_ptr, guest_addr, (copy) ? sizeof(*host_ptr) : 0)
 
-#if defined(CONFIG_USE_NPTL)
 #include <pthread.h>
-#endif
 
 /* Include target-specific struct and function definitions;
  * they may need access to the target-independent structures

linux-user/syscall.c

@@ -111,13 +111,8 @@ int __clone2(int (*fn)(void *), void *child_stack_base,
 
 #include "qemu.h"
 
-#if defined(CONFIG_USE_NPTL)
 #define CLONE_NPTL_FLAGS2 (CLONE_SETTLS | \
     CLONE_PARENT_SETTID | CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID)
-#else
-/* XXX: Hardcode the above values.  */
-#define CLONE_NPTL_FLAGS2 0
-#endif
 
 //#define DEBUG
 
@@ -234,12 +229,10 @@ _syscall1(int,exit_group,int,error_code)
 #if defined(TARGET_NR_set_tid_address) && defined(__NR_set_tid_address)
 _syscall1(int,set_tid_address,int *,tidptr)
 #endif
-#if defined(CONFIG_USE_NPTL)
 #if defined(TARGET_NR_futex) && defined(__NR_futex)
 _syscall6(int,sys_futex,int *,uaddr,int,op,int,val,
           const struct timespec *,timeout,int *,uaddr2,int,val3)
 #endif
-#endif
 #define __NR_sys_sched_getaffinity __NR_sched_getaffinity
 _syscall3(int, sys_sched_getaffinity, pid_t, pid, unsigned int, len,
           unsigned long *, user_mask_ptr);
@@ -4227,7 +4220,6 @@ abi_long do_arch_prctl(CPUX86State *env, int code, abi_ulong addr)
 
 #define NEW_STACK_SIZE 0x40000
 
-#if defined(CONFIG_USE_NPTL)
 
 static pthread_mutex_t clone_lock = PTHREAD_MUTEX_INITIALIZER;
 typedef struct {
@@ -4272,16 +4264,6 @@ static void *clone_func(void *arg)
     /* never exits */
     return NULL;
 }
-#else
-
-static int clone_func(void *arg)
-{
-    CPUArchState *env = arg;
-    cpu_loop(env);
-    /* never exits */
-    return 0;
-}
-#endif
 
 /* do_fork() Must return host values and target errnos (unlike most
    do_*() functions). */
@@ -4292,12 +4274,8 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp,
     int ret;
     TaskState *ts;
     CPUArchState *new_env;
-#if defined(CONFIG_USE_NPTL)
     unsigned int nptl_flags;
     sigset_t sigmask;
-#else
-    uint8_t *new_stack;
-#endif
 
     /* Emulate vfork() with fork() */
     if (flags & CLONE_VFORK)
@@ -4305,10 +4283,9 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp,
 
     if (flags & CLONE_VM) {
         TaskState *parent_ts = (TaskState *)env->opaque;
-#if defined(CONFIG_USE_NPTL)
         new_thread_info info;
         pthread_attr_t attr;
-#endif
+
         ts = g_malloc0(sizeof(TaskState));
         init_task_state(ts);
         /* we create a new CPU instance. */
@@ -4321,7 +4298,6 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp,
         new_env->opaque = ts;
         ts->bprm = parent_ts->bprm;
         ts->info = parent_ts->info;
-#if defined(CONFIG_USE_NPTL)
         nptl_flags = flags;
         flags &= ~CLONE_NPTL_FLAGS2;
 
@@ -4371,17 +4347,6 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp,
         pthread_cond_destroy(&info.cond);
         pthread_mutex_destroy(&info.mutex);
         pthread_mutex_unlock(&clone_lock);
-#else
-        if (flags & CLONE_NPTL_FLAGS2)
-            return -EINVAL;
-        /* This is probably going to die very quickly, but do it anyway.  */
-        new_stack = g_malloc0 (NEW_STACK_SIZE);
-#ifdef __ia64__
-        ret = __clone2(clone_func, new_stack, NEW_STACK_SIZE, flags, new_env);
-#else
-	ret = clone(clone_func, new_stack + NEW_STACK_SIZE, flags, new_env);
-#endif
-#endif
     } else {
         /* if no CLONE_VM, we consider it is a fork */
         if ((flags & ~(CSIGNAL | CLONE_NPTL_FLAGS2)) != 0)
@@ -4392,7 +4357,6 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp,
             /* Child Process.  */
             cpu_clone_regs(env, newsp);
             fork_end(1);
-#if defined(CONFIG_USE_NPTL)
             /* There is a race condition here.  The parent process could
                theoretically read the TID in the child process before the child
                tid is set.  This would require using either ptrace
@@ -4408,7 +4372,6 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp,
                 cpu_set_tls (env, newtls);
             if (flags & CLONE_CHILD_CLEARTID)
                 ts->child_tidptr = child_tidptr;
-#endif
         } else {
             fork_end(0);
         }
@@ -4834,7 +4797,6 @@ static inline abi_long host_to_target_stat64(void *cpu_env,
 }
 #endif
 
-#if defined(CONFIG_USE_NPTL)
 /* ??? Using host futex calls even when target atomic operations
    are not really atomic probably breaks things.  However implementing
    futexes locally would make futexes shared between multiple processes
@@ -4886,7 +4848,6 @@ static int do_futex(target_ulong uaddr, int op, int val, target_ulong timeout,
         return -TARGET_ENOSYS;
     }
 }
-#endif
 
 /* Map host to target signal numbers for the wait family of syscalls.
    Assume all other status bits are the same.  */
@@ -5132,9 +5093,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
                     abi_long arg5, abi_long arg6, abi_long arg7,
                     abi_long arg8)
 {
-#ifdef CONFIG_USE_NPTL
     CPUState *cpu = ENV_GET_CPU(cpu_env);
-#endif
     abi_long ret;
     struct stat st;
     struct statfs stfs;
@@ -5148,7 +5107,6 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
 
     switch(num) {
     case TARGET_NR_exit:
-#ifdef CONFIG_USE_NPTL
         /* In old applications this may be used to implement _exit(2).
            However in threaded applictions it is used for thread termination,
            and _exit_group is used for application termination.
@@ -5186,7 +5144,6 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
             g_free(ts);
             pthread_exit(NULL);
         }
-#endif
 #ifdef TARGET_GPROF
         _mcleanup();
 #endif
@@ -8687,11 +8644,9 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
         }
 	break;
 #endif
-#if defined(CONFIG_USE_NPTL)
     case TARGET_NR_futex:
         ret = do_futex(arg1, arg2, arg3, arg4, arg5, arg6);
         break;
-#endif
 #if defined(TARGET_NR_inotify_init) && defined(__NR_inotify_init)
     case TARGET_NR_inotify_init:
         ret = get_errno(sys_inotify_init());