mips-stub.c

RTEMS (Real-Time Executive for Multiprocessor Systems) is a free open source real-time operating sys

               strcpy (outBuffer, "E01"); /* E01 = bad 'm' command */
            break;


         case 'X':  /* XAA..AA,LLLL:<binary data>#cs */
            binary = 1;
         case 'M':
            /* MAA..AA,LLLL:  Write LLLL bytes at address AA..AA - return OK */
            ptr = &inBuffer[1];
            if (hexToInt (&ptr, &addr)
                && *ptr++ == ','
                && hexToInt (&ptr, &length)
                && *ptr++ == ':'
                && is_writeable (addr, length) ) {
               if ( binary )
                  hex2mem (ptr, (void *)addr, length);
               else
                  bin2mem (ptr, (void *)addr, length);
               strcpy (outBuffer, "OK");
            }
            else
               strcpy (outBuffer, "E02"); /* E02 = bad 'M' command */
            break;



         case 'c':
            /* cAA..AA    Continue at address AA..AA(optional) */
         case 's':
            /* sAA..AA    Step one instruction from AA..AA(optional) */
         {
            /* try to read optional parameter, pc unchanged if no parm */
            ptr = &inBuffer[1];
            if (hexToInt (&ptr, &addr))
               registers[PC] = addr;

            if (inBuffer[0] == 's')
               doSStep ();
         }
         goto stubexit;





         case 'k':  /* remove all zbreaks if any */
        dumpzbreaks:
         {
            {
               /* Unlink the entire list */
               struct z0break *z0, *znxt;

               while( (z0= z0break_list) )
               {

                  /* put back the instruction */
                  if( z0->instr != 0xffffffff )
                     *(z0->address) = z0->instr;

                  /* pop off the top entry */
                  znxt = z0->next;
                  if( znxt ) znxt->prev = NULL;
                  z0break_list = znxt;

                  /* and put it on the free list */
                  z0->prev = NULL;
                  z0->next = z0break_avail;
                  z0break_avail = z0;
               }
            }

            strcpy(outBuffer, "OK");
         }
         break;





         case 'q':   /* queries */
#if defined(GDB_STUB_ENABLE_THREAD_SUPPORT)
            rtems_gdb_process_query( inBuffer, outBuffer, do_threads, thread );
#endif
            break;

#if defined(GDB_STUB_ENABLE_THREAD_SUPPORT)
         case 'T':
         {
            int testThread;

            if( vhstr2thread(&inBuffer[1], &testThread) == NULL ) 
            {
               strcpy(outBuffer, "E01");
               break;
            }

            if( rtems_gdb_index_to_stub_id(testThread) == NULL )
            {
               strcpy(outBuffer, "E02");
            }
            else
            {
               strcpy(outBuffer, "OK");
            }
         }
         break;
#endif
        
         case 'H':  /* set new thread */
#if defined(GDB_STUB_ENABLE_THREAD_SUPPORT)
            if (inBuffer[1] != 'g') {
               break;
            }
	  
            if (!do_threads) {
               break;
            }
	  
            {
               int tmp, ret;
	    
               /* Set new generic thread */
               if (vhstr2thread(&inBuffer[2], &tmp) == NULL) {
                  strcpy(outBuffer, "E01");
                  break;
               }

               /* 0 means `thread' */
               if (tmp == 0) {
                  tmp = thread;
               }

               if (tmp == current_thread) {
                  /* No changes */
                  strcpy(outBuffer, "OK");
                  break;
               }

               /* Save current thread registers if necessary */ 
               if (current_thread != thread) {
                  ret = rtems_gdb_stub_set_thread_regs(
                     current_thread, (unsigned int *) &current_thread_registers);
                  ASSERT(ret);
               }

               /* Read new registers if necessary */
               if (tmp != thread) {
                  ret = rtems_gdb_stub_get_thread_regs(
                     tmp, (unsigned int *) &current_thread_registers);

                  if (!ret) {
                     /* Thread does not exist */
                     strcpy(outBuffer, "E02");
                     break;
                  }
               }
	    
               current_thread = tmp;
               strcpy(outBuffer, "OK");
            }
#endif
            break;




         case 'Z':  /* Add breakpoint */
         { 
            int ret, type, len;
            unsigned *address;
            struct z0break *z0;

            ret = parse_zbreak(inBuffer, &type, (unsigned char **)&address, &len);
            if (!ret) {
               strcpy(outBuffer, "E01");
               break;
            }

            if (type != 0) {
               /* We support only software break points so far */
               strcpy(outBuffer, "E02");
               break;
            }

            if (len != R_SZ) {     /* was 1 */
               strcpy(outBuffer, "E03");
               break;
            }

            /* Let us check whether this break point already set */
            for (z0=z0break_list; z0!=NULL; z0=z0->next) {
               if (z0->address == address) {
                  break;
               }
            }

            if (z0 != NULL) {
               /* we already have a breakpoint for this address */
               strcpy(outBuffer, "E04");
               break;
            }

            /* Let us allocate new break point */
            if (z0break_avail == NULL) {
               strcpy(outBuffer, "E05");
               break;
            }


            /* Get entry */
            z0 = z0break_avail;
            z0break_avail = z0break_avail->next;

            /* Let us copy memory from address add stuff the break point in */
            /*
            *if (mem2hstr(z0->buf, address, 1) == NULL ||
              !hstr2mem(address, "cc" , 1)) { 

               * Memory error *
               z0->next = z0break_avail;
               z0break_avail = z0;
               strcpy(outBuffer, "E05");
               break;
            }*/

            /* Fill it */
            z0->address = address;

            if( z0->address == (unsigned *) frame->epc )
            {
               /* re-asserting the breakpoint that put us in here, so
               we'll add the breakpoint but leave the code in place
               since we'll be returning to it when the user continues */
               z0->instr = 0xffffffff;
            }
            else
            {
               /* grab the instruction */
               z0->instr = *(z0->address);
               /* and insert the break */
               *(z0->address) = BREAK_INSTR;
            }

            /* Add to the list */
            {
               struct z0break *znxt = z0break_list;

               z0->prev = NULL;
               z0->next = znxt;
               
               if( znxt ) znxt->prev = z0;
               z0break_list = z0;
            }

            strcpy(outBuffer, "OK");
         }
         break;


         case 'z': /* remove breakpoint */
            if (inBuffer[1] == 'z') 
            {
               goto dumpzbreaks;
               

               /*
                * zz packet - remove all breaks *
                z0last = NULL;

                for (z0=z0break_list; z0!=NULL; z0=z0->next) 
                {
                if(!hstr2mem(z0->address, z0->buf, R_SZ)) 
                {
                ret = 0;
                }
                z0last = z0;
                }

                * Free entries if any *
                if (z0last != NULL) {
                z0last->next  = z0break_avail;
                z0break_avail = z0break_list;
                z0break_list  = NULL;
                }

                if (ret) {
                strcpy(outBuffer, "OK");
                } else {
                strcpy(outBuffer, "E04");
                }
                break;
               */
            }
            else
            {
               int ret, type, len;
               unsigned *address;
               struct z0break *z0;
              

               ret = parse_zbreak(inBuffer, &type, (unsigned char **)&address, &len);
               if (!ret) {
                  strcpy(outBuffer, "E01");
                  break;
               }

               if (type != 0) {
                  /* We support only software break points so far */
                  break;
               }

               if (len != R_SZ) {
                  strcpy(outBuffer, "E02");
                  break;
               }
	   
               /* Let us check whether this break point set */
               for (z0=z0break_list; z0!=NULL; z0=z0->next) {
                  if (z0->address == address) {
                     break;
                  }
               }
              
               if (z0 == NULL) {
                  /* Unknown breakpoint */
                  strcpy(outBuffer, "E03");
                  break;
               }
	    
               /*
               if (!hstr2mem(z0->address, z0->buf, R_SZ)) {
                  strcpy(outBuffer, "E04");
                  break;
                  }*/

               if( z0->instr != 0xffffffff )
               {
                  /* put the old instruction back  */
                  *(z0->address) = z0->instr;
               }
   
               /* Unlink entry */
               {
                  struct z0break *zprv = z0->prev, *znxt = z0->next;

                  if( zprv ) zprv->next = znxt;
                  if( znxt ) znxt->prev = zprv;

                  if( !zprv ) z0break_list = znxt;

                  znxt = z0break_avail;

                  z0break_avail = z0;
                  z0->prev = NULL;
                  z0->next = znxt;
               }
    
               strcpy(outBuffer, "OK");
            }
            break;


         default: /* do nothing */
            break;
      }

      /* reply to the request */
      putpacket (outBuffer);
   }

  stubexit:

   /*
    *  The original code did this in the assembly wrapper.  We should consider
    *  doing it here before we return.
    *
    *  On exit from the exception handler invalidate each line in the I-cache
    *  and write back each dirty line in the D-cache.  This needs to be done
    *  before the target program is resumed in order to ensure that software
    *  breakpoints and downloaded code will actually take effect.  This
    *  is because modifications to code in ram will affect the D-cache,
    *  but not necessarily the I-cache.
    */

   {
      extern void clear_cache();
      clear_cache();
   }

   return;
}










static int numsegs;
static struct memseg   memsegments[NUM_MEMSEGS];

int gdbstub_add_memsegment( unsigned base, unsigned end, int opts )
{
   if( numsegs == NUM_MEMSEGS ) return -1;

   memsegments[numsegs].begin = base;
   memsegments[numsegs].end   = end;
   memsegments[numsegs].opts   = opts;

   ++numsegs;
   return RTEMS_SUCCESSFUL;
}




static int is_readable(unsigned ptr, unsigned len)
{
   struct memseg *ms;
   int i;

   if( (ptr & 0x3) ) return -1;

   for(i=0; i<numsegs; i++)
   {
      ms= &memsegments[i];

      if( ms->begin <= ptr && ptr+len <= ms->end && (ms->opts & MEMOPT_READABLE) )
         return -1;
   }
   return 0;
}


static int is_writeable(unsigned ptr, unsigned len)
{
   struct memseg *ms;
   int i;

   if( (ptr & 0x3) ) return -1;

   for(i=0; i<numsegs; i++)
   {
      ms= &memsegments[i];

      if( ms->begin <= ptr && ptr+len <= ms->end && (ms->opts & MEMOPT_WRITEABLE) )
         return -1;
   }
   return 0;
}


static int is_steppable(unsigned ptr)
{
   struct memseg *ms;
   int i;

   if( (ptr & 0x3) ) return -1;

   for(i=0; i<numsegs; i++)
   {
      ms= &memsegments[i];

      if( ms->begin <= ptr && ptr <= ms->end && (ms->opts & MEMOPT_WRITEABLE) )
         return -1;
   }
   return 0;
}














static char initialized = 0;   /* 0 means we are not initialized */

void mips_gdb_stub_install(int enableThreads) 
{
   /*
     These are the RTEMS-defined vectors for all the MIPS exceptions
   */
   int exceptionVector[]= { MIPS_EXCEPTION_MOD, \
                            MIPS_EXCEPTION_TLBL, \
                            MIPS_EXCEPTION_TLBS, \
                            MIPS_EXCEPTION_ADEL, \
                            MIPS_EXCEPTION_ADES, \
                            MIPS_EXCEPTION_IBE, \
                            MIPS_EXCEPTION_DBE, \
                            MIPS_EXCEPTION_SYSCALL, \
                            MIPS_EXCEPTION_BREAK, \
                            MIPS_EXCEPTION_RI, \
                            MIPS_EXCEPTION_CPU, \
                            MIPS_EXCEPTION_OVERFLOW, \
                            MIPS_EXCEPTION_TRAP, \
                            MIPS_EXCEPTION_VCEI, \
                            MIPS_EXCEPTION_FPE, \
                            MIPS_EXCEPTION_C2E, \
                            MIPS_EXCEPTION_WATCH, \
                            MIPS_EXCEPTION_VCED, \
                            -1 };
   int  i;
   rtems_isr_entry old;

   if (initialized) 
   {
      ASSERT(0);
      return;
   }

   memset( memsegments,0,sizeof(struct memseg)*NUM_MEMSEGS );
   numsegs = 0;

#if defined(GDB_STUB_ENABLE_THREAD_SUPPORT)
   if( enableThreads )
      do_threads = 1;
   else
      do_threads = 0;
#endif

   {
      struct z0break *z0;

      z0break_avail = NULL;
      z0break_list  = NULL;
   
      /* z0breaks list init, now we'll do it so it makes sense... */
      for (i=0; i<BREAKNUM; i++) 
      {
         memset( (z0= &z0break_arr[i]), 0, sizeof(struct z0break));

         z0->next = z0break_avail;
         z0break_avail = z0;
      }
   }     

   for(i=0; exceptionVector[i] > -1; i++)
   {
      rtems_interrupt_catch( (rtems_isr_entry) handle_exception, exceptionVector[i], &old );
   }

   initialized = 1;

   /* get the attention of gdb */
   /* mips_break(1);  disabled so user code can choose to invoke it or not */
}