blackfin bf561 FreeRTOS implementation fail at runtime when loading a task

Question

I've implemented in Blackfin BF561 coreB FreeRTOS from the code:

http://www.freertos.org/index.html?http://interactive.freertos.org/forums/79366-analog-devices

I converted to bare metal as elf executable using gcc.

I'm close but I have a runtime error that I cannot figuer out. When the scheduler start and try to trigger the first task, the memory pointer get lost and it doesn't start the first stack, instead in start a function inside the first task and get lost when going out of the function.

this is the corresponding debug log:

COREB: end setup LED                                                            
COREB: handler declared                                                         
COREB: Initialise New TCB:NewTCB address: 3d01000                               
COREB: TopofStask: 0, pxTopOfStack = 3d0263c                                    
COREB: pxTaskCode =3c033a0, pvParameters = 0                                    
COREB: returned pxNewTCB->pxTopOfStack = 3d02588                                
COREB: task created:                                                            
COREB: top of stack: 3d02588                                                    
COREB: GenericListItem: 0                                                       
COREB: Event ListItem: 9                                                        
COREB: Priority: 1                                                              
COREB: start of stack: 3d02000                                                  
COREB: Task Name: BootTas                                                       
COREB: TCB number: 0                                                            
COREB: Task Tag: 0                                                              
COREB: Add the idle task at the lowest priority                                 
COREB: Initialise New TCB:NewTCB address: 3d03000                               
COREB: TopofStask: 0, pxTopOfStack = 3d0431c                                    
COREB: pxTaskCode =3c0295c, pvParameters = 0                                    
COREB: returned pxNewTCB->pxTopOfStack = 3d04268                                
COREB: task created:                                                            
COREB: top of stack: 3d04268                                                    
COREB: GenericListItem: 0                                                       
COREB: Event ListItem: a                                                        
COREB: Priority: 0                                                              
COREB: start of stack: 3d04000                                                  
COREB: Task Name: IDLE                                                          
COREB: TCB number: 1                                                            
COREB: Task Tag: 0                                                              
COREB: end Add the idle task at the lowest priority                             
COREB: if xReturn == 1, and xReturn = 1                                         
COREB: before disable interupt                                                  
COREB: after disable interupt                                                   
COREB: before  xPortStartScheduler                                              
COREB: start xPortStartScheduler fn before set core timer                       
COREB: after ContextSwitch interupt flag                                        
COREB: before prvSetupTimerInterrupt                                            
COREB: after prvSetupTimerInterupt                                              
COREB: Task Switch context called                                               
COREB: The scheduler is running                                                 
COREB: trace switched out TCB:ff700bf8                                          
COREB: name of switch out task:efore  xPortStartScheduler                       

COREB: before Task first check for stack overflow                               
COREB: Task first check for stack overflow called                               
COREB: Task second check for stack overflow called                              
COREB: before call get owner of next entry                                      
COREB: get owner of next entry:                                                 
COREB: current TCB 3d01000                                                      
COREB: pxReadyTasksLists[ uxTopReadyPriority ] = 1                              
COREB: TCB content:                                                             
COREB: top of stack: 3d02588                                                    
COREB: GenericListItem: 0                                                       
COREB: Event ListItem: 9                                                        
COREB: Priority: 1                                                              
COREB: start of stack: 3d02000                                                  
COREB: Task Name: BootTas                                                       
COREB: TCB number: 0                                                            
COREB: Task Tag: 0                                                              
COREB: trace switched in:BootTas                                                
COREB: write trace to buffer                                                    
COREB: task increment tick: 1                                                   
COREB: end of app init                                                          
COREB: execption 2b addr ff700be4                                               
COREB: coreb dump stack                                                         
COREB: found fp: ff700b64  

and this is the discution I started on the Analog Device forum:

http://ez.analog.com/message/38669#38669

Answer 1

Ok I finally resolve the issue. the problem was that the assembler code was not return from the vContext code interruption function with the RTI, instead it was go straight through to the next assembler code function which was the timer interrupt which had the same problem and thus the stack pointer was then going to the next address which happen to be the starting address for the app_init function.....

May the problem was due to the fact that the RTI statement was made in a MACRO called by the vContextSwitch function, I'm not sure.

I fixed it by converting those assembler function to C function and now the stack return from interrupt work properly and the problem is fixed. Note that additional error was found after that which was forgotten of hook task loader function in the scheduler when calling vContextSwhitch as well as the tag of the hook function that was never recorded in the context of the task.

All fixed now.

Best Regards,

William