Support task_wait / task_wait_tid syscalls:

    - Add task_end2 syscall to allow pthread_exit-like retval.
    - Add/maintain task states.
    - Create task parent/child tracking tree.
    - Add task_detach function.
    - Implement wait syscalls.

Make task_exec caller the parent of spawned task:

    Previously the task_exec call caused a message to the
    VFS task, which called task_create and returned the tid
    in response to the message.  This causes the parent of
    the spawned task to appear to be the VFS task.

    Modify task_exec / VFS handling to instead return the
    entry point address on the message and have task_exec call
    task_create directly itself.

Change-Id: I6b6796f45875de37b1ab01e7596639b073820b95
Reviewed-on: http://gfw160.austin.ibm.com:8080/gerrit/443
Tested-by: Jenkins Server
Reviewed-by: Daniel M. Crowell <dcrowell@us.ibm.com>
Reviewed-by: Andrew J. Geissler <andrewg@us.ibm.com>

1 files changed, 9 insertions, 2 deletions

diff --git a/src/kernel/basesegment.C b/src/kernel/basesegment.C
index 4cb2c39cb..dee18600a 100644
--- a/src/kernel/basesegment.C
+++ b/src/kernel/basesegment.C
@@ -131,7 +131,14 @@ int BaseSegment::_mmAllocBlock(MessageQueue* i_mq,void* i_va,uint64_t i_size)
 
 uint64_t BaseSegment::findPhysicalAddress(uint64_t i_vaddr) const
 {
-    if(i_vaddr < iv_physMemSize) return i_vaddr;
+    if(i_vaddr < iv_physMemSize)
+    {
+        // Anything in the physical address size is valid (and linear mapped)
+        // except NULL.
+        if (i_vaddr >= PAGE_SIZE)
+            return i_vaddr;
+        else return -EFAULT;
+    }
     return (iv_block ? iv_block->findPhysicalAddress(i_vaddr) : -EFAULT);
 }
 
@@ -170,7 +177,7 @@ int BaseSegment::_mmSetPermission(void* i_va, uint64_t i_size, uint64_t i_access
       // Check to see if there is a next block
       if (l_block->iv_nextBlock)
       {
-	// set local block to the next block 
+	// set local block to the next block
 	l_block = l_block->iv_nextBlock;
       }
       else