[src/trunk]: src/sys/arch/mips/mips - Make a modification to reduce the cost ...

[nisimura <nisimura%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/7e7b64f76422
branches:  trunk
changeset: 473323:7e7b64f76422
user:      nisimura <nisimura%NetBSD.org@localhost>
date:      Sat May 29 09:38:28 1999 +0000

description:
- Make a modification to reduce the cost of TLBmod exception handling.
TLBUpdate() routine is used for dual purposes.  In TLBmod case, just ok
to call 'tlbwi' (as designed).  Result in saving of extraneous execution
path.  MIPS1 only this moment.

diffstat:

 sys/arch/mips/mips/locore_mips1.S |  37 ++++++++++++++++++++++++++++---------
 sys/arch/mips/mips/trap.c         |  12 ++++++++++--
 2 files changed, 38 insertions(+), 11 deletions(-)

diffs (136 lines):

diff -r 1c7b562714eb -r 7e7b64f76422 sys/arch/mips/mips/locore_mips1.S
--- a/sys/arch/mips/mips/locore_mips1.S Sat May 29 09:31:02 1999 +0000
+++ b/sys/arch/mips/mips/locore_mips1.S Sat May 29 09:38:28 1999 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: locore_mips1.S,v 1.12 1999/05/22 02:35:35 nisimura Exp $       */
+/*     $NetBSD: locore_mips1.S,v 1.13 1999/05/29 09:38:28 nisimura Exp $       */
 
 /*
  * Copyright (c) 1992, 1993
@@ -1068,7 +1068,7 @@
  *             unsigned highreg, lowreg;
  *
  * Results:
- *     None.
+ *     None.           (XXX not correct XXX)
  *
  * Side effects:
  *     None.
@@ -1078,6 +1078,17 @@
 LEAF(mips1_TLBUpdate)
        mfc0    v1, MIPS_COP_0_STATUS           # Save the status register.
        mtc0    zero, MIPS_COP_0_STATUS         # Disable interrupts
+
+       li      v0, -1                          #
+       bne     v0, a0, 3f                      #
+       mtc0    a1, MIPS_COP_0_TLB_LOW          # this is the way MIPS
+       nop                                     # TLB exception
+       tlbwi                                   # handlers should be
+       nop                                     # implemented.
+       j       ra                              #
+       mtc0    v1, MIPS_COP_0_STATUS           #
+
+3:
        mfc0    t0, MIPS_COP_0_TLB_HI           # Save current PID
        nop                                     # 2 cycles before intr disabled
        mtc0    a0, MIPS_COP_0_TLB_HI           # init high reg.
@@ -1702,6 +1713,7 @@
        mtc0    v1, MIPS_COP_0_STATUS           # restore status register
 END(mips1_purge_perprocess_tlb)
 
+#if notyet_for_PMAP_NEW
 /*
  * mips1_purge_single_tlb(vaddr_t)
  *
@@ -1737,14 +1749,20 @@
 /*
  * void mips1_update_tlb(vaddr, unsigned)
  *
- * Replace an entry which has the same VPN with the same TLBPID or
- * global bit, if any.  If no such entry exists, add the new entry
- * into TLB victimizing a ramdomly choosen one.
+ * Used dual purposes; update current TLB entry just made TLB exception
+ * with the given entrylo value.  Or, replace an entry which has the
+ * given VPN with the given TLBPID or with global bit, if any.  If no
+ * such entry exists, add the new entry into TLB victimizing a ramdomly
+ * choosen one.
  */
 LEAF(mips1_update_tlb)
        mfc0    v1, MIPS_COP_0_STATUS           # save status register
        mtc0    zero, MIPS_COP_0_STATUS         # disable interrupts
 
+       li      v0, -1                          # check to use current entryhi
+       beq     v0, a0, 2f
+       mtc0    a1, MIPS_COP_0_TLB_LOW          # set new entrylo
+
        mfc0    v0, MIPS_COP_0_TLB_HI           # pick current TLBPID
        srl     a0, 12
        sll     a0, 12                          # obtain VPN
@@ -1754,17 +1772,18 @@
        nop
        tlbp                                    # probe looking for the entry
        mfc0    t0, MIPS_COP_0_TLB_INDEX        # see what we got
+       nop
+       bgtz    t0, 1f                          # index < 0 => !found
        mtc0    a1, MIPS_COP_0_TLB_LOW
-       bltz    t0, 1f                          # index < 0 => !found
-       nop
        b       2f
-       tlbwi                                   # update an entry found
+       tlbwr                                   # add vicitimizing another
 1:
-       tlbwr                                   # add vicitimizing another
+       tlbwi                                   # update the entry
 2:
        j       ra
        mtc0    v1, MIPS_COP_0_STATUS           # restore status register
 END(mips1_update_tlb)
+#endif
 
 /*
  * void mips1_clean_tlb(void)
diff -r 1c7b562714eb -r 7e7b64f76422 sys/arch/mips/mips/trap.c
--- a/sys/arch/mips/mips/trap.c Sat May 29 09:31:02 1999 +0000
+++ b/sys/arch/mips/mips/trap.c Sat May 29 09:38:28 1999 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: trap.c,v 1.109 1999/05/18 03:13:37 nisimura Exp $      */
+/*     $NetBSD: trap.c,v 1.110 1999/05/29 09:38:28 nisimura Exp $      */
 
 /*
  * Copyright (c) 1988 University of Utah.
@@ -43,7 +43,7 @@
  */
 
 #include <sys/cdefs.h>                 /* RCS ID & Copyright macro defns */
-__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.109 1999/05/18 03:13:37 nisimura Exp $");
+__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.110 1999/05/29 09:38:28 nisimura Exp $");
 
 #include "opt_cputype.h"       /* which mips CPU levels do we support? */
 #include "opt_inet.h"
@@ -451,8 +451,12 @@
                        }
                        entry |= mips_pg_m_bit();
                        pte->pt_entry = entry;
+#if defined(MIPS1) && !defined(MIPS3)
+                       MachTLBUpdate(~0, entry);       /* use entryhi */
+#else
                        vaddr &= ~PGOFSET;
                        MachTLBUpdate(vaddr, entry);
+#endif
                        pa = pfn_to_vad(entry);
                        if (!IS_VM_PHYSADDR(pa)) {
                                printf("ktlbmod: va %x pa %lx\n", vaddr, pa);
@@ -484,9 +488,13 @@
                }
                entry |= mips_pg_m_bit();
                pte->pt_entry = entry;
+#if defined(MIPS1) && !defined(MIPS3)
+               MachTLBUpdate(~0, entry);               /* use entryhi */
+#else
                vaddr = (vaddr & ~PGOFSET) |
                        (pmap->pm_asid << MIPS_TLB_PID_SHIFT);
                MachTLBUpdate(vaddr, entry);
+#endif
                pa = pfn_to_vad(entry);
                if (!IS_VM_PHYSADDR(pa)) {
                        printf("utlbmod: va %x pa %lx\n", vaddr, pa);