FreeCalypso > hg > fc-tourmaline

view src/cs/riviera/support/exception.c @ 220:0ed36de51973

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
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

/*
 ******************************
 * 
 *
 * Initialial version: Laurent Deniau, Laurent.Deniau@cern.ch
 *
 * For more information, please see the paper:
 * http://cern.ch/Laurent.Deniau/html/oopc/exception.html
 * 
 * -----------------------------------------------------------
 *
 * Strong rework and adaption to riviera by Christophe Favergeon
 *
 ******************************
 */

// Authorization to use this source code communicated to Christophe Favergeon
// by email

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include "support/exception.h"

#ifndef _WINDOWS
  #include "config/swconfig.cfg"
#endif


/* global stack of exception context */
struct _exceptionContext_ *const _returnExceptionContext_[MAX_RVF_TASKS]=
#if (!GSMLITE)
  {NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,
  NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL};
#else
  {NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL};
#endif

struct _exceptionContext_ *_currentExceptionContext_ [MAX_RVF_TASKS]= 
#if (!GSMLITE)
  {NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,
  NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL};
#else
  {NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL};
#endif

/* delete protected pointers and throw exception */
void
_exceptionThrow_(int exception)
{
  struct _protectedPtr_ *p;
  struct _protectedPtr_ *oldp;

  /* no exception context saved, exit program */
  if (!_currentExceptionContext_[rvf_get_taskid()]) exit(exception); 

  /* free pointers stored on the current exception context pointers stack */
  p=_currentExceptionContext_[rvf_get_taskid()]->stack;

  while(p)
  {
	  oldp=p->previous;
	  p->func(p->ptr);
	  rvf_free_buf(p);
	  p=oldp;
  }

  _currentExceptionContext_[rvf_get_taskid()]->stack=NULL;

  /* jump to previous exception context */
  rvf_restore_context_buffer_(_currentExceptionContext_[rvf_get_taskid()]->context, exception); 
} 


// Protect a pointer when there is a try/ctahc block active
void rvf_protect_pointer(T_RVF_MB_ID mb_id,void *p,T_RVF_RELEASE_PROTECTED_POINTER func)
{

	struct _protectedPtr_ *ptr;
	struct _exceptionContext_ *context;
	T_RVF_MB_STATUS err;



	if (_currentExceptionContext_[rvf_get_taskid()])
	{

	if (p==NULL)
		throw(E_not_enough_memory);

	context=_currentExceptionContext_[rvf_get_taskid()];
	err=rvf_get_buf(mb_id,sizeof(struct _protectedPtr_),(void*)&ptr);
	

	if (err==RVF_GREEN)
	{
		ptr->next=NULL;
	    ptr->previous=NULL;
	    ptr->ptr=p;
	    ptr->func=func;

         if (context->stack==NULL)
		 {
			  context->stack=ptr;
		 }
		 else
		 {
			  ptr->previous=context->stack;
			  context->stack->next=ptr;
			  context->stack=ptr;
		 }
	 }
	 else
	 {
		 if (p!=NULL)
		   rvf_free_buf(p);
		 throw(E_not_enough_memory);
	 }
	}
}

void rvf_forget_protected_ptr()
{
   struct _protectedPtr_ *p;
   struct _protectedPtr_ *oldp;

   p=_currentExceptionContext_[rvf_get_taskid()]->stack;

   while(p)
   {
	   oldp=p->previous;
	   rvf_free_buf(p);
	   p=oldp;
   }

   _currentExceptionContext_[rvf_get_taskid()]->stack=NULL;
}