sched/tls: add nxsched_get_stackargs

Thread args have already been saved to stack after the TLS section by
nxtask_setup_stackargs. This is to retrieve it for use.

Signed-off-by: Yanfeng Liu <yfliu2008@qq.com>

include/nuttx/tls.h

@@ -219,6 +219,7 @@ struct tls_info_s
   int16_t tl_cpcount;                  /* Nested cancellation point count */
 #endif
 
+  uint16_t tl_size;                    /* Actual size with alignments */
   int tl_errno;                        /* Per-thread error number */
 };
 

sched/sched/sched.h

@@ -393,5 +393,6 @@ bool nxsched_verify_tcb(FAR struct tcb_s *tcb);
 
 struct tls_info_s; /* Forward declare */
 FAR struct tls_info_s *nxsched_get_tls(FAR struct tcb_s *tcb);
+FAR char **nxsched_get_stackargs(FAR struct tcb_s *tcb);
 
 #endif /* __SCHED_SCHED_SCHED_H */

sched/sched/sched_get_tls.c

@@ -53,3 +53,25 @@ FAR struct tls_info_s *nxsched_get_tls(FAR struct tcb_s *tcb)
 
   return (FAR struct tls_info_s *)tcb->stack_alloc_ptr;
 }
+
+/****************************************************************************
+ * Name: nxsched_get_stackargs
+ *
+ * Description:
+ *   Get args from thread's stack w/o security checks. The args are setup in
+ *   nxtask_setup_stackargs().
+ *
+ * Input Parameters:
+ *   tcb - The tcb to query.
+ *
+ * Returned Value:
+ *   Pointer to a list of stack arguments ended by a NULL pointer.
+ *
+ ****************************************************************************/
+
+FAR char **nxsched_get_stackargs(FAR struct tcb_s *tcb)
+{
+  /* The args data follows the TLS data */
+
+  return (FAR char**)(tcb->stack_alloc_ptr + nxsched_get_tls(tcb)->tl_size);
+}

sched/tls/tls_initinfo.c

@@ -63,6 +63,10 @@ int tls_init_info(FAR struct tcb_s *tcb)
 
   up_tls_initialize(info);
 
+  /* Derive tl_size w/o arch knowledge */
+
+  info->tl_size = tcb->stack_base_ptr - tcb->stack_alloc_ptr;
+
   /* Attach per-task info in group to TLS */
 
   info->tl_task = tcb->group->tg_info;