mem_control.c

一个用在mips体系结构中的操作系统

/*
 * Copyright (C) 1996-1998 by the Board of Trustees
 *    of Leland Stanford Junior University.
 * 
 * This file is part of the SimOS distribution. 
 * See LICENSE file for terms of the license. 
 *
 */

/****************************************************************
 * mem_control.c
 * 
 * Author: $Author: bosch $
 * Date:   $Date: 1998/02/10 00:30:41 $
 *****************************************************************/
/* include the sim stuff first so we don't expand our macros in their code */
#include <stdio.h>
#include <unistd.h>
#include "simmisc.h"

#include "embra.h"
#include "mem_control.h"
#include "qc.h"
#include "cache.h"
#include "debug.h"
#include "driver.h"
#include "cp0.h"
#include "clock.h"
#include "main_run.h"
#include "tc_coherence.h"
#include "stats.h"
#include "callout.h"
#include "main_run.h"
#include "tc.h"
#include "annotations.h"

PA mem_translate( int cpuNum, VA vAddr )
{
  PA pAddr;
  int status;


#ifdef wrongl_place
  
  /*
   * This is definitively not the right place to do this. 
   * As a matter of fact, we should get rid of sim_misc.first....
   * altogether. 
   * (bugnion)
   */
  
  /* Should I enter the debugger?  -- Since this is done in Periodic_Callout,*/
  /* This is really just to handle cpus in the prom slave loop */
  if( sim_misc.first_cpu_into_debugger != -1 ) {
	 Embra_Collect_Processes_For_Debug(cpuNum);
  }
#endif

  /* Since this is the start of a basic block, we are not in the delay slot */ 
  status = Em_TranslateVirtual( cpuNum, vAddr, &pAddr, ACT_IREAD);

  if( status == BACKDOOR_CODE ) {
     /* Assume this is a call. Execute it on the real CPU. This
      * assumes all backdoor calls take less than 4 arguments. 
      */
     /* If we are counting time for the translator, stop */
     STAT_TIMER_STOP( trans_timer );

     /* Set this global ONLY for backdoor calls where we don't want to */
     /* force a cpuNum parameter */
     /*     curr_cpu = cpuNum; */
     curEmp = &EMP[cpuNum];

     STAT_INC( backdoor_calls );

     if( !EMP[cpuNum].outOfSlaveLoop ) {
        /* This CPU has not been kicked yet -- it's in the PROM */
        uint launchAddr = (uint)sim_misc.launchAddr[cpuNum];
        if( !embra.MPinUP )
           if(!launchAddr) sginap(20); /* XXX ??? */
        /* Get master's cycle count */
        EMP[cpuNum].cycleCount = EMP[0].cycleCount;
        /* Make time go foward */
        EMP[cpuNum].cycleCountdown = 0;

        /* XXX - non-backdoor address is launch, backdoor address is call */
        if( IS_BACKDOOR( launchAddr ) ) {
           int64 result;
           /* Do call */
           result = ((int64 (*)(int,int,int,int))launchAddr)
              ( sim_misc.launchArg[cpuNum][0],
                sim_misc.launchArg[cpuNum][1],
                sim_misc.launchArg[cpuNum][2],
                sim_misc.launchArg[cpuNum][3] );

           if( result == SLAVELOOP_CONTINUE ) {
              /* signal init function done */
              sim_misc.launchAddr[cpuNum] = 0;
              /* clear so will be 0 if not set up on next call */
              sim_misc.launchArg[cpuNum][0] = 0;
	      sim_misc.launchArg[cpuNum][1] = 0;
	      sim_misc.launchArg[cpuNum][2] = 0;
	      sim_misc.launchArg[cpuNum][3] = 0;
              CPUPut("Slave %d returning to launch wait\n",cpuNum );
           }
        } else {
           if( launchAddr != 0 ) {
              /* Start emulation */
              CPUWarning("Launch slave PC 0x%x\n", launchAddr);
              /* Note we set PC to RA before returning from here */
              EMP[cpuNum].R[31] = launchAddr;
              EMP[cpuNum].cpuStatus = cpu_running;
              EMP[cpuNum].R[REG_A0] = sim_misc.launchArg[cpuNum][0];
              EMP[cpuNum].R[REG_A1] = sim_misc.launchArg[cpuNum][1];
              EMP[cpuNum].R[REG_A2] = sim_misc.launchArg[cpuNum][2];
              EMP[cpuNum].R[REG_A3] = sim_misc.launchArg[cpuNum][3];
              EMP[cpuNum].outOfSlaveLoop = 1;
           } 
        }
     } else {
        /* Not a Prom call, just do it */
        int64 bdoorRetval;
        ASSERT(pAddr < 0x80000000);
        bdoorRetval = ((int64 (*)(int,int,int,int))pAddr)
           (EMP[cpuNum].R[REG_A0],
            EMP[cpuNum].R[REG_A1],
            EMP[cpuNum].R[REG_A2],
            EMP[cpuNum].R[REG_A3]);
        EMP[cpuNum].R[2] = bdoorRetval >> 32;
        EMP[cpuNum].R[3] = bdoorRetval & 0xffffffff;
     }
     ASSERT( embra.emode == EMBRA_PAGE ||embra.sequential || EMP[cpuNum].outTC );
     EMP[cpuNum].PC = EMP[cpuNum].R[31];
     ASSERT( (EMP[cpuNum].PC & 0x3) == 0 );
     if (embra.MPinUP) {
        /* NOTE: to get things to boot we need to do a CX after the */
        /* slave loop.  */
        if( !EMP[cpuNum].outOfSlaveLoop ) {
           EMP[cpuNum].jumpPC = (uint)continue_run_without_chaining;
           ReenterTC_CX( &EMP[cpuNum] );
           ASSERT(0);
           /* NOT REACHED */
        }
     }
     ReenterTC( &EMP[cpuNum] );
     /* NOT REACHED */
  }

  if( status == EXCEPTION_CODE ) {
     ReenterTC(&EMP[cpuNum]);
     ASSERT(0);
     /* NOT REACHED */
     return 0;
  }
  return pAddr;
#ifdef gone
  return PHYS_TO_MEMADDR(M_FROM_CPU(cpuNum), pAddr);
#endif
}

static int debugOnWatchpoint[SIM_MAXCPUS];

/* called on miss in Quickcheck and Physarray 
 * In virtual quickcheck mode we first have to check
 * the physical quickcheck in phys_mem_ref */
MA  mem_ref( VA vAddr, EmVQCMemState new_state, int cpuNum )
{
   int prevTCGenNumber = tcGenNumber;
   PA pAddr;
   int status;
   Em_accesstype act;
   MA retval;

   exceptionDuringBackdoor = FALSE;
   if( VQC_INST(new_state) ) {
      vAddr = IN_BD(EMP[cpuNum].PC)?CLEAR_BD(EMP[cpuNum].PC)+INST_SIZE:
         EMP[cpuNum].PC;
      act = ACT_IREAD;
   } else {
      act = VQC_EXCL( new_state ) ? ACT_DWRITE : ACT_DREAD;
   }

   /* In cache mode, PQC missed, in page mode, mmu reloc missed */
   STAT_PQC(new_state);

   status = Em_TranslateVirtual( cpuNum, vAddr, &pAddr, act );

   /*
    * I guess that we could check even if the translation fails, but
    * it's overall faster to do it this way
    */

   if (status==NORMAL_CODE && annWatchpoints == TRUE) {
      if (VQC_SHARED(new_state)) {
         EmbraAnnExec(cpuNum,AnnFMLookup(vAddr, ANNFM_LD_TYPE),ANNFM_LD_TYPE);
      }
      if (VQC_EXCL(new_state)) {
         EmbraAnnExec(cpuNum,AnnFMLookup(vAddr, ANNFM_ST_TYPE),ANNFM_ST_TYPE);
      }
   }

   if( status == NORMAL_CODE ) {
      /* NOTE: this code detects the case where we write code and then */
      /* jump to it.  In that case we need to downgrade the code so we */
      /* can detect future writes.  This detection occurs here and in */
      /* pc_tc_lookup depending on whether we detect the condition when */
      /* we jump to the code, or if we are executing inside a */
      /* traslation */
      if( embra.emode == EMBRA_PAGE ) {
         if( VQC_EXCL( new_state ) ) {
            if( EmbraTCCoherenceCheck( cpuNum, vAddr,pAddr, pAddr+8 ) ) {
               CPUWarning("Flushing the TC in mem_ref:1 (TC coherence) PC=0x%llx vAddr=0x%llx \n",
                          (Reg64)EMP[cpuNum].PC, (Reg64)vAddr);

               ReenterTC( &EMP[cpuNum] );
               /* NOT REACHED */
            }
         }

#ifdef EMBRA_USE_QC64
         if( VQC_INST( new_state )) {
            /* Downgrade page to read/execute so we can detect */
            /* writes to it */ 
            qc_downgrade( cpuNum, vAddr, new_state );
         }
#else
         if( VQC_INST( new_state ) && 
             (IS_MMU_PROT_WRITE(EMP[cpuNum].mmu[PAGE_NUMBER(vAddr)]) ) ) {
            /* Downgrade page to read/execute so we can detect */
            /* writes to it */ 
            qc_downgrade( cpuNum, vAddr, new_state );
         }
#endif
         /* This returns to callout.s */
         return PHYS_TO_MEMADDR(M_FROM_CPU(cpuNum), pAddr);
      } else {
         /* ASSERT(embra.emode == EMBRA_CACHE); */
         /* If we are doing cache simulation, make the reference */
         if( NUM_CPUS(M_FROM_CPU(cpuNum)) == 1 ) {
            UPCache_Ref( cpuNum, pAddr, vAddr, new_state );
         } else {
            if( embra.MPinUP ) {
               MPinUPCache_Ref( cpuNum, pAddr, vAddr, new_state );
            } else {
               MPCache_Ref( cpuNum, pAddr, vAddr, new_state );
            }
         }

         if( VQC_INST( new_state )){
            if (embra.useVQC){
               if (VQC_EXCL(EMP[cpuNum].qc_v[ADDR2SLINE(vAddr)])) {
                  /* Downgrade page to read/execute so we can detect */
                  /* writes to it */ 
                  qc_downgrade( cpuNum, vAddr, new_state );
 
               }
            } else {              /* !useVQC */
#ifdef EMBRA_USE_QC64
               if (1) { /* alway safe to do in QC64 */
#else
               if (IS_MMU_PROT_WRITE(EMP[cpuNum].mmu[PAGE_NUMBER(vAddr)]) )  {
#endif
                  /* Downgrade page to read/execute so we can detect */
                  /* writes to it */ 
                  qc_downgrade( cpuNum, vAddr, new_state );
               }
            }
         }

         /* This maintains a data structure which allows us to determine */
         /* if we are writing to a page which has code in it which we are */
         /* exectuing.  If such a conflict occurs, we flush the TC and */
         /* ReenterTC with the pc value */
         /* This is conservative because most stores are not doubles */
            if( VQC_EXCL( new_state ) ) {
               if( EmbraTCCoherenceCheck( cpuNum, vAddr,pAddr, pAddr+8 ) ) {
                  CPUWarning("Flushing the TC in mem_ref:2 (TC coherence) PC=0x%llx vAddr=0x%llx \n",
                             (Reg64)EMP[cpuNum].PC, (Reg64)vAddr);

                  ReenterTC( &EMP[cpuNum] );
                  /* NOT REACHED */
               }
            }
        
         /* And return Zero indicating rewind the QC */
         if( embra.sequential ) {
            /* No need to rewind in
               MPinUP, if line is stolen
               during stall, access
               still suceeds, but sc fails */
            return PHYS_TO_MEMADDR(M_FROM_CPU(cpuNum), pAddr);
         } else {
            return 0;
         }
      }
   }
   else if (status == BACKDOOR_CODE) {
      if (tcGenNumber != prevTCGenNumber) {
         /*
          * the TC was flushed during the badoor data addressed function
          * at this point, the RT register has already been set, 
          * so we simply reenter the TC. 
          * Caveat: we better NOT be in a BD. 
          */
         if (!exceptionDuringBackdoor) { 
            CPUPrint("EMBRA: %10lld cpu=%d TC flushed on backdoor ref (ok) \n",
                     (uint64) EmbraCpuCycleCount(cpuNum),cpuNum);
            ASSERT( !IN_BD(EMP[cpuNum].PC));
            EMP[cpuNum].PC += INST_SIZE;
            EMP[cpuNum].cycleCountdown--;
         } else {
            ASSERT( !(EMP[cpuNum].CP0[C0_CAUSE] & CAUSE_BD));
            EMP[cpuNum].CP0[C0_EPC] += INST_SIZE; 
                 /* Don't reexecute on return */
         }
         ReenterTC(&EMP[cpuNum]);
      }
      exceptionDuringBackdoor = FALSE;

      /*
       * XXX this cast is very important and makes sense. 
       */
      
      return (MA)pAddr;
   }
           
   else {
      if (status != EXCEPTION_CODE) { 
         CPUWarning("PROBABLY a user-levle SIGSEGV! stats=0x%x when 0x%x (EXCEPTION_CODE) expected.cpu=%d vAddr=0x%x  \n",
                    status,EXCEPTION_CODE,cpuNum,vAddr);
         Em_EXCEPTION(cpuNum, (act==ACT_IREAD) ? EXC_IBE : EXC_DBE, 0);
         ReenterTC( &EMP[cpuNum] );
         /* NOT REACHED */
         return 0;
      }
      ASSERT( status == EXCEPTION_CODE );
      ReenterTC( &EMP[cpuNum] );
      /* NOT REACHED */
      return 0;
   }
}


/* *****************************************************
 * EmbraTCCoherenceCheck
 * *****************************************************/
 
static int just_flushed;
static VA last_pc;
static PA last_pAddr;

int EmbraTCCoherenceCheck(int cpuNum, VA vAddr, PA pAddr, PA end)
{
   if (TCcoherence_check(PHYS_TO_MEMADDR(M_FROM_CPU(cpuNum), pAddr),
                         PHYS_TO_MEMADDR(M_FROM_CPU(cpuNum), end))) {
      
      if( just_flushed ) {
         /* This catches and disallows an infinite loop case */
         /* The problem is that the kernel writes say the UTLB miss */
         /* handler, then flushed the cache.  The cache flush looks */
         /* like a self-writing line because we just flushed from */
         /* the write.  We special case this by checking for vAddr */
         /* == 0 */
         if( (EMP[cpuNum].PC == last_pc) && (pAddr == last_pAddr) &&
             vAddr ) { 
            CPUWarning("SELF-WRITING  LINE code PA 0x%x VA 0x%x vPC 0x%x pPC 0x%x\n", 
                       pAddr, vAddr, EMP[cpuNum].PC,
                       K0_TO_PHYS_REMAP(non_excepting_tv(cpuNum,
                                                         EMP[cpuNum].PC),
                                        cpuNum) ); 
         } 
         return 0; 
      }
      
      /* This doesn't add appreciable cost, so always maintain it */
      em_stats.icache_coherence++;
      /*
        CPUWarning("Write to code PA 0x%x VA 0x%x PC 0x%x\n",
        pAddr, vAddr, EMP[cpuNum].PC );
        */
      /* Kernel text is overwritten (ex. UTLB miss handler) */
      Clear_Translation_State(TCFLUSH_ALL );
      last_pc = EMP[cpuNum].PC;
      last_pAddr = pAddr;
      just_flushed = 1;
      if( IN_BD( EMP[cpuNum].PC ) ) {
         EMP[cpuNum].PC = CLEAR_BD( EMP[cpuNum].PC );
         EMP[cpuNum].PC -= INST_SIZE;
      }
      ASSERT( (EMP[cpuNum].PC & 0x3) == 0 );
#if 0
      CPUWarning("TCcoherence_check_code detected conflict at pc=0x%llx. \n",
                 (Reg64)EMP[cpuNum].PC);
#endif
      return 1;
   } else { 
      just_flushed = 0;
      return 0;
   }
}