view src/cs/services/cst/cst_stack.c @ 220:0ed36de51973

ABB semaphore protection overhaul The ABB semaphone protection logic that came with TCS211 from TI was broken in several ways: * Some semaphore-protected functions were called from Application_Initialize() context. NU_Obtain_Semaphore() called with NU_SUSPEND fails with NU_INVALID_SUSPEND in this context, but the return value wasn't checked, and NU_Release_Semaphore() would be called unconditionally at the end. The latter call would increment the semaphore count past 1, making the semaphore no longer binary and thus no longer effective for resource protection. The fix is to check the return value from NU_Obtain_Semaphore() and skip the NU_Release_Semaphore() call if the semaphore wasn't properly obtained. * Some SPI hardware manipulation was being done before entering the semaphore- protected critical section. The fix is to reorder the code: first obtain the semaphore, then do everything else. * In the corner case of L1/DSP recovery, l1_abb_power_on() would call some non-semaphore-protected ABB & SPI init functions. The fix is to skip those calls in the case of recovery. * A few additional corner cases existed, all of which are fixed by making ABB semaphore protection 100% consistent for all ABB functions and code paths. There is still one remaining problem of priority inversion: suppose a low- priority task calls an ABB function, and some medium-priority task just happens to preempt right in the middle of that semaphore-protected ABB operation. Then the high-priority SPI task is locked out for a non-deterministic time until that medium-priority task finishes its work and goes back to sleep. This priority inversion problem remains outstanding for now.
author Mychaela Falconia <falcon@freecalypso.org>
date Mon, 26 Apr 2021 20:55:25 +0000
parents 4e78acac3d88
children
line wrap: on
line source

/*******************************************************************************
 *
 * CST_STACK.C
 *
 * Tasks and HISRs stacks monitoring.
 *
 * (C) Texas Instruments 2000
 *
 ******************************************************************************/

#include <stdio.h>
#include <string.h>

#include "nucleus.h"
#include "cs_defs.h"
#include "tc_defs.h"

// The following stack sizes are defined in int.s
#define IRQ_STACK_SIZE  128                // Number of bytes in IRQ stack
#define FIQ_STACK_SIZE  512                // Number of bytes in FIQ stack.
#define SYSTEM_SIZE     1024               // Define the system stack size

int vsi_o_trace (char * caller, unsigned long tclass, char * text);
int vsi_t_sleep (char * caller,	unsigned long tvalue);

void CST_stack_trace()
{
  int jndex, count, char_count;
  TC_TCB *head, *ptr;
  extern CS_NODE *TCD_Created_Tasks_List;
  extern CS_NODE *TCD_Created_HISRs_List;
  unsigned untouched;
  char *top_stack, *top, *bottom;
  extern char *TCT_System_Limit;
  char result[80];
  char name[9];

  vsi_o_trace("CST", 0x08, "Stack Info ...");
  vsi_o_trace("CST", 0x08, "    Name  top       bottom    current   untouched");
  vsi_o_trace("CST", 0x08, "-------------------------------------------------");

  for (jndex=0; jndex<2; jndex++)
  {
     // make use of TCB and HCB having same structure from beginning to past stack info
     if (jndex == 0)
         ptr = head = (TC_TCB *)TCD_Created_Tasks_List;
     else {
         ptr = head = (TC_TCB *)TCD_Created_HISRs_List;
         vsi_o_trace("CST", 0x08, "-------------------------------------------------");
     }

     count = 0;
     do
     {
       untouched = 0;
       top_stack = (char *)ptr->tc_stack_start;
       while (*top_stack == 0xFE && top_stack <= (char *)ptr->tc_stack_end)
       {
         untouched++;
         top_stack++;
       }

       // Avoid to get a spurious character when tasks names are 8 characters long
       memcpy (name, ptr->tc_name, 8);
       name[8] = 0;

       sprintf(result, "%8s: %08x  %08x  %08x  0x%x", 
                              name, 
                              ptr->tc_stack_start,
                              ptr->tc_stack_end,
                              ptr->tc_stack_pointer,
                              untouched);
       vsi_o_trace("CST", 0x08, result);
       vsi_t_sleep("",30);

       ptr = (TC_TCB*) ptr->tc_created.cs_next;
    } while (ptr != head && count++ < 50);  //count is protection from infinite loops
  } // end of  for (jndex=0; jndex<2; jndex++)

  // stack allocation algorithm from the int.s function INT_Initialize()
  //
  //   \          \
  //   \----------\
  //   \          \
  //   \          \
  //   \          \
  //   \ SYSSTACK \
  //   \          \
  //   \          \
  //   \          \
  //   \----------\
  //   \          \
  //   \ IRQSTACK \
  //   \          \
  //   \----------\
  //   \          \
  //   \          \
  //   \ FIQSTACK \
  //   \          \
  //   \          \
  //   \----------\
  //   \          \

  untouched = 0;
  top_stack = top = (char *)TCT_System_Limit;
  bottom = (char *) ((unsigned)TCT_System_Limit + SYSTEM_SIZE);
  while (*top_stack == 0xFE && top_stack <= bottom)
  {
     untouched++;
     top_stack++;
  }

  // "CST" being the current active task with its related CST_Stack,
  // the System Stack is unused (current sp_svc = System Stack Bottom)
  sprintf(result, "SYSSTACK: %08x  %08x  %08x  0x%x", 
                          top,
                          bottom,
						  bottom, // current sp_svc = System Stack Bottom
                          untouched);
  vsi_o_trace("CST", 0x08, "-------------------------------------------------");
  vsi_o_trace("CST", 0x08, result);
  vsi_t_sleep("",30);

  untouched = 0;
  top_stack = top = bottom + 4;
  bottom = (char *) ((unsigned)bottom + IRQ_STACK_SIZE);
  while (*top_stack == 0xFE && top_stack <= bottom)
  {
    untouched++;
    top_stack++;
  }

  // Since the processor is in supervisor mode (no IRQ & no FIQ),
  // current sp_irq = IRQ Stack bottom
  sprintf(result, "IRQSTACK: %08x  %08x  %08x  0x%x", 
                          top,
                          bottom,
						  bottom, // current sp_irq = IRQ Stack bottom
                          untouched);
  vsi_o_trace("CST", 0x08, result);
  vsi_t_sleep("",30);

  untouched = 0;
  top_stack = top = bottom + 4;
  bottom = (char *) ((unsigned)bottom + FIQ_STACK_SIZE);
  while (*top_stack == 0xFE && top_stack <= bottom)
  {
    untouched++;
    top_stack++;
  }

  // Since the processor is in supervisor mode (no IRQ & no FIQ),
  // current sp_fiq = FIQ Stack bottom
  sprintf(result, "FIQSTACK: %08x  %08x  %08x  0x%x", 
                          top,
                          bottom,
						  bottom, // current sp_fiq = FIQ Stack bottom
                          untouched);
  vsi_o_trace("CST", 0x08, result);
  vsi_o_trace("CST", 0x08, "-------------------------------------------------");
  vsi_t_sleep("",30);
}