Changeset 648 for soft/giet_vm/giet_kernel/kernel_init.c

Timestamp:

Jul 22, 2015, 1:11:08 PM (9 years ago)

Author:

alain

Message:

Introducing support for the new mechanism to start tasks.

File:

• soft/giet_vm/giet_kernel/kernel_init.c (modified) (7 diffs)

soft/giet_vm/giet_kernel/kernel_init.c

@@ -266 +266 @@
     //            initialisation, from values stored in the tasks contexts.
     //          - set CTX_RA slot  with the kernel _ctx_eret() virtual address.
-    //          - set CTX_EPC slot that must contain the task entry point, 
+    //          - set CTX_ENTRY slot that must contain the task entry point, 
     //            and contain only at this point the virtual address of the 
-    //            memory slot containing this entry point. 
+    //            memory word containing this entry point. 
     ////////////////////////////////////////////////////////////////////////////
 
@@ -283 +283 @@
         _ptabs_ptprs[vsid][x][y] = ptpr;
 
-        // set the ptpr to use the local page table
+        // set the PTPR to use the local page table
         asm volatile( "mtc2    %0,   $0"
                       : : "r" (ptpr) );
 
-        // compute ctx_ra
+        // set CTX_RA slot
         unsigned int ctx_ra = (unsigned int)(&_ctx_eret);
         _set_task_slot( x, y, p, ltid, CTX_RA_ID, ctx_ra );
 
-        // compute ctx_epc
-        unsigned int* ptr = (unsigned int*)_get_task_slot(x,y,p,ltid,CTX_EPC_ID);
-        _set_task_slot( x , y , p , ltid , CTX_EPC_ID , *ptr );
+        // set CTX_ENTRY slot
+        unsigned int* ptr = (unsigned int*)_get_task_slot(x , y , p , ltid , CTX_ENTRY_ID);
+        unsigned int ctx_entry = *ptr;
+        _set_task_slot( x , y , p , ltid , CTX_ENTRY_ID , ctx_entry );
 
 #if GIET_DEBUG_INIT
@@ -300 +301 @@
         " - ptabs_vaddr[%d][%d][%d] = %x\n"
         " - ptabs_paddr[%d][%d][%d] = %l\n"
-        " - ctx_epc              = %x\n"
+        " - ctx_entry            = %x\n"
         " - ctx_ra               = %x\n",
         x , y , p , ltid ,  
         vsid , x , y , ptab ,
         vsid , x , y , ((unsigned long long)ptpr)<<13 ,
-        _get_task_slot( x, y, p, ltid, CTX_EPC_ID ),
-        _get_task_slot( x, y, p, ltid, CTX_RA_ID ) );
+        ctx_entry, ctx_ra );
 #endif
 
@@ -316 +316 @@
 
     ////////////////////////////////////////////////////////////////////////////
-    // step 3 : - Each processor complete idle task context initialisation,
-    //            (only the CTX_SP, CTX_RA, CTX_EPC slot, because the CTX_PTPR
-    //            and CTX_PTAB slots have been initialised in boot code)
+    // step 3 : - Each processor complete idle task context initialisation.
+    //            Only CTX_SP, CTX_RA, CTX_EPC slots, because other slots
+    //            have been initialised in boot code)
     //            The 4 Kbytes idle stack is implemented in the scheduler itself.
-    //          - Each processor starts TICK timer, as soon as at least one task
-    //            is allocated.
+    //          - Each processor starts TICK timer, if at least one task.
     //          - P[0,0,0] initialises FAT (not done before, because it must 
     //            be done after the _ptabs_vaddr[v][x][y] array initialisation, 
@@ -327 +326 @@
     ////////////////////////////////////////////////////////////////////////////
 
-    unsigned int sp  = ((unsigned int)psched) + 0x2000;
-    unsigned int ra  = (unsigned int)(&_ctx_eret);
-    unsigned int epc = (unsigned int)(&_idle_task);
-
-    _set_task_slot( x , y , p , IDLE_TASK_INDEX , CTX_SP_ID  , sp  );
-    _set_task_slot( x , y , p , IDLE_TASK_INDEX , CTX_RA_ID  , ra  );
-    _set_task_slot( x , y , p , IDLE_TASK_INDEX , CTX_EPC_ID , epc );
+    unsigned int sp    = ((unsigned int)psched) + 0x2000;
+    unsigned int ra    = (unsigned int)(&_ctx_eret);
+    unsigned int entry = (unsigned int)(&_idle_task);
+
+    _set_task_slot( x , y , p , IDLE_TASK_INDEX , CTX_SP_ID  , sp    );
+    _set_task_slot( x , y , p , IDLE_TASK_INDEX , CTX_RA_ID  , ra    );
+    _set_task_slot( x , y , p , IDLE_TASK_INDEX , CTX_ENTRY_ID , entry );
 
     if (tasks > 0) _xcu_timer_start( cluster_xy, p, GIET_TICK_VALUE ); 
@@ -358 +357 @@
 
     ////////////////////////////////////////////////////////////////////////////
-    // step 4 : Each processor compute values for registers SP, SR, PTPR, EPC,
-    //          corresponding to the first allocated task (can be idle task)
-    //          and jumps to user code.
+    // step 4 : Each processor computes the task index (ltid), and the values
+    //          to initialize the SP, SR, PTPR, EPC registers.
+    //          It jumps to a runable task if possible, and jumps to IDLE-TASK 
+    //          if no task allocated or no runable task.
     ////////////////////////////////////////////////////////////////////////////
 
@@ -366 +366 @@
                             x, y, p );
 
-    if (tasks == 0) ltid = IDLE_TASK_INDEX;
-    else            ltid = 0;
-
+    // default value for ltid
+    ltid = IDLE_TASK_INDEX;
+
+    // scan allocated tasks to find a runable task
+    unsigned int  task_id; 
+    for ( task_id = 0 ; task_id < tasks ; task_id++ )
+    {
+        if ( _get_task_slot( x, y, p, task_id, CTX_NORUN_ID ) == 0 )
+        {
+            ltid = task_id;
+            break;
+        }
+    }
+
+    // update scheduler
+    psched->current = ltid;
+
+    // get values from selected task context
     unsigned int sp_value   = _get_task_slot( x, y, p, ltid, CTX_SP_ID);
     unsigned int sr_value   = _get_task_slot( x, y, p, ltid, CTX_SR_ID);
     unsigned int ptpr_value = _get_task_slot( x, y, p, ltid, CTX_PTPR_ID);
-    unsigned int epc_value  = _get_task_slot( x, y, p, ltid, CTX_EPC_ID);
-
-#if GIET_DEBUG_INIT
-_printf("\n[DEBUG KINIT] P[%d,%d,%d] jumps to user code at cycle %d\n"
+    unsigned int epc_value  = _get_task_slot( x, y, p, ltid, CTX_ENTRY_ID);
+
+#if GIET_DEBUG_INIT
+_printf("\n[DEBUG KINIT] P[%d,%d,%d] completes kernel_init at cycle %d\n"
         " ltid = %d / sp = %x / sr = %x / ptpr = %x / epc = %x\n",
         x , y , p , _get_proctime() ,