[Qemu-devel] [PATCH] implement CLONE_CHILD_CLEARTID

[Lauro Ramos Venancio <lauro.venancio@openbossa.org>]

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The attached patch implements the clone flag CLONE_CHILD_CLEARTID.

-- 
Lauro Ramos Venancio
INdT - Instituto Nokia de Tecnologia

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Index: qemu-arm-eabi/linux-user/syscall.c
===================================================================
--- qemu-arm-eabi.orig/linux-user/syscall.c	2008-10-13 19:10:54.000000000 -0300
+++ qemu-arm-eabi/linux-user/syscall.c	2008-10-13 19:31:01.000000000 -0300
@@ -3177,6 +3177,7 @@
     pthread_cond_t cond;
     pthread_t thread;
     uint32_t tid;
+    unsigned int flags;
     abi_ulong child_tidptr;
     abi_ulong parent_tidptr;
     sigset_t sigmask;
@@ -3190,9 +3191,11 @@
     env = info->env;
     thread_env = env;
     info->tid = gettid();
-    if (info->child_tidptr)
+    if (info->flags & CLONE_CHILD_SETTID)
         put_user_u32(info->tid, info->child_tidptr);
-    if (info->parent_tidptr)
+    if (info->flags & CLONE_CHILD_CLEARTID)
+        set_tid_address(g2h(info->child_tidptr));
+    if (info->flags & CLONE_PARENT_SETTID)
         put_user_u32(info->tid, info->parent_tidptr);
     /* Enable signals.  */
     sigprocmask(SIG_SETMASK, &info->sigmask, NULL);
@@ -3257,7 +3260,6 @@
         nptl_flags = flags;
         flags &= ~CLONE_NPTL_FLAGS2;
 
-        /* TODO: Implement CLONE_CHILD_CLEARTID.  */
         if (nptl_flags & CLONE_SETTLS)
             cpu_set_tls (new_env, newtls);
 
@@ -3269,7 +3271,9 @@
         pthread_mutex_lock(&info.mutex);
         pthread_cond_init(&info.cond, NULL);
         info.env = new_env;
-        if (nptl_flags & CLONE_CHILD_SETTID)
+        info.flags = nptl_flags;
+        if (nptl_flags & CLONE_CHILD_SETTID ||
+            nptl_flags & CLONE_CHILD_CLEARTID)
             info.child_tidptr = child_tidptr;
         if (nptl_flags & CLONE_PARENT_SETTID)
             info.parent_tidptr = parent_tidptr;
@@ -3332,7 +3336,8 @@
             ts = (TaskState *)env->opaque;
             if (flags & CLONE_SETTLS)
                 cpu_set_tls (env, newtls);
-            /* TODO: Implement CLONE_CHILD_CLEARTID.  */
+            if (flags & CLONE_CHILD_CLEARTID)
+                set_tid_address(g2h(child_tidptr));
         } else {
             fork_end(0);
         }

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