Thread-local memory

core/include/tcb.h

@@ -55,6 +55,8 @@ typedef struct tcb_t {
     cib_t msg_queue;
     msg_t *msg_array;
 
+    char *lcoal_mem;
+
     const char *name;
     char *stack_start;
     int stack_size;

core/include/thread.h

@@ -17,6 +17,7 @@
  *
  * @author      Freie Universität Berlin, Computer Systems & Telematics
  * @author      Kaspar Schleiser <kaspar@schleiser.de>
+ * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
  */
 
 #ifndef __THREAD_H
@@ -49,6 +50,37 @@
 */
 int thread_create(char *stack, int stacksize, char priority, int flags, void (*function) (void), const char *name);
 
+
+/**
+ * @brief   Reserve a given amount of memory on the top of the stack as thread local memory
+ *
+ * Always reserve the full number size of bytes or none, do not try to fit as many bytes as possible into the stack
+ *
+ * @param   stack Lowest address of preallocated stack space
+ * @param   stacksize
+ * @param   localmemsize        number of bytes to reserve for the thread-local memory (taken from given stack memory)
+ * @param   flags Options:
+ * YIELD: force context switch.
+ * CREATE_SLEEPING: set new thread to sleeping state, thread must be woken up manually.
+ * CREATE_STACKTEST: initialize stack with values needed for stack overflow testing.
+ *
+ * @param priority Priority of newly created thread. Lower number means higher
+ * priority. 0 means highest possible priority. Lowest priority is
+ * PRIORITY_IDLE-1, usually 30.
+ *
+ * @return  returns <0 on error, pid of newly created task else.
+ */
+int thread_create_with_local_mem(char *stack, int stacksize, int localmemsize, char priority, 
+                                 int flags, void (*function) (void), const char *name);
+
+/**
+ * @brief   Acces the threads local memory
+ *
+ * @param[in] pid       pid of the thread to access
+ * @return pointer to the threads local memory, 0 on error
+ */
+char *thread_get_local_mem(int pid);
+
 /**
  * @brief   returns the status of a process.
  * @return  STATUS_NOT_FOUND if pid is unknown

core/thread.c

@@ -14,6 +14,7 @@
  * @brief       Threading implementation
  *
  * @author      Kaspar Schleiser <kaspar.schleiser@fu-berlin.de>
+ * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
  *
  * @}
  */
@@ -199,6 +200,8 @@ int thread_create(char *stack, int stacksize, char priority, int flags, void (*f
     cb->rq_entry.next = NULL;
     cb->rq_entry.prev = NULL;
 
+    cb->local_mem = NULL;
+
     cb->name = name;
 
     cb->wait_data = NULL;
@@ -237,3 +240,25 @@ int thread_create(char *stack, int stacksize, char priority, int flags, void (*f
 
     return pid;
 }
+
+int thread_create_with_local_mem(char *stack, int stacksize, int localmemsize, char priority, 
+                                 int flags, void (*function) (void), const char *name)
+{
+    // the thread-local memory is put in the beginning
+    char *localmam = stack;
+    stack += localmemsize;
+    stacksize -= localmemsize;
+
+    // create the thread
+    int pid = thread_create(stack, stacksize, priority, flags, function, name);
+
+    // set pointer to local mem
+    sched_threads[pid]->local_mem = localmem;
+
+    return pid;
+}
+
+char *thread_get_local_mem(int pid)
+{
+    return sched_threads[pid]->local_mem;
+}