[Qemu-devel] [5068] [sh4] MMU bug fix

[Aurelien Jarno]

Revision: 5068
          http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=5068
Author:   aurel32
Date:     2008-08-22 08:57:52 +0000 (Fri, 22 Aug 2008)

Log Message:
-----------
[sh4] MMU bug fix

Some bugs on SH4 MMU are fixed.

- When a TLB entry is overwritten or invalidated, tlb_flush_page() should be
  invoked to invalidate old entry.
- When a ASID is changed, tlb_flush() should be invoke to invalidate entries
  which have old ASID.
- The check for shared bit in TLB entry causes multiple TLB hit exception.
  As SH3's MMU, shared bit is ignored.
- ASID is used when MMUCR's SV bit or SR's MD bit is zero.
  No need to check both bits are zero.

(Shin-ichiro KAWASAKI)

Modified Paths:
--------------
    trunk/hw/sh7750.c
    trunk/target-sh4/helper.c

Modified: trunk/hw/sh7750.c
===================================================================
--- trunk/hw/sh7750.c   2008-08-22 08:57:43 UTC (rev 5067)
+++ trunk/hw/sh7750.c   2008-08-22 08:57:52 UTC (rev 5068)
@@ -30,6 +30,7 @@
 #include "sh7750_regs.h"
 #include "sh7750_regnames.h"
 #include "sh_intc.h"
+#include "exec-all.h"
 #include "cpu.h"
 
 #define NB_DEVICES 4
@@ -356,6 +357,9 @@
        s->cpu->mmucr = mem_value;
        return;
     case SH7750_PTEH_A7:
+        /* If asid changes, clear all registered tlb entries. */
+       if ((s->cpu->pteh & 0xff) != (mem_value & 0xff))
+           tlb_flush(s->cpu, 1);
        s->cpu->pteh = mem_value;
        return;
     case SH7750_PTEL_A7:

Modified: trunk/target-sh4/helper.c
===================================================================
--- trunk/target-sh4/helper.c   2008-08-22 08:57:43 UTC (rev 5067)
+++ trunk/target-sh4/helper.c   2008-08-22 08:57:52 UTC (rev 5068)
@@ -251,7 +251,7 @@
     for (i = 0; i < nbtlb; i++) {
        if (!entries[i].v)
            continue;           /* Invalid entry */
-       if (use_asid && entries[i].asid != asid && !entries[i].sh)
+       if (use_asid && entries[i].asid != asid)
            continue;           /* Bad ASID */
 #if 0
        switch (entries[i].sz) {
@@ -320,8 +320,14 @@
     else if (e == MMU_DTLB_MISS && update) {
        e = find_tlb_entry(env, address, env->utlb, UTLB_SIZE, use_asid);
        if (e >= 0) {
+           tlb_t * ientry;
            n = itlb_replacement(env);
-           env->itlb[n] = env->utlb[e];
+           ientry = &env->itlb[n];
+           if (ientry->v) {
+               if (!same_tlb_entry_exists(env->utlb, UTLB_SIZE, ientry))
+                   tlb_flush_page(env, ientry->vpn << 10);
+           }
+           *ientry = env->utlb[e];
            e = n;
        } else if (e == MMU_DTLB_MISS)
            e = MMU_ITLB_MISS;
@@ -356,7 +362,7 @@
     int use_asid, is_code, n;
     tlb_t *matching = NULL;
 
-    use_asid = (env->mmucr & MMUCR_SV) == 0 && (env->sr & SR_MD) == 0;
+    use_asid = (env->mmucr & MMUCR_SV) == 0 || (env->sr & SR_MD) == 0;
     is_code = env->pc == address;      /* Hack */
 
     /* Use a hack to find if this is an instruction or data access */
@@ -540,6 +546,17 @@
     int n = cpu_mmucr_urc(env->mmucr);
     tlb_t * entry = &env->utlb[n];
 
+    if (entry->v) {
+        /* Overwriting valid entry in utlb. */
+        target_ulong address = entry->vpn << 10;
+       if (!same_tlb_entry_exists(env->itlb, ITLB_SIZE, entry)) {
+           tlb_flush_page(env, address);
+       }
+    }
+
+    /* per utlb access cannot implemented. */
+    increment_urc(env);
+
     /* Take values into cpu status from registers. */
     entry->asid = (uint8_t)cpu_pteh_asid(env->pteh);
     entry->vpn  = cpu_pteh_vpn(env->pteh);