[Qemu-devel] [PATCH] sparc32 MMU fixes

[Robert Reif <reif@earthlink.net>]

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This patch adds support for some more MMU registers:
    0x10   TLB replacement control
    0x13   read/write access to 0x03 SFSR
    0x14   read/write access to 0x04 SFAR
Only support for 1 real register was added (0x10) but 16 were added
to CPUSPARCState because we don't check for invalid register
accesses yet.  Different CPUs use different registers and there isn't
enough documentation to work out what is valid or not so we just
waste some space.

This patch also preserves the bits we are not interested in for tlb
flushing in the processor control register (0x00).

[-- Attachment #2: mmu.diff.txt --]
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Index: target-sparc/cpu.h
===================================================================
RCS file: /sources/qemu/qemu/target-sparc/cpu.h,v
retrieving revision 1.58
diff -p -u -r1.58 cpu.h
--- target-sparc/cpu.h	10 Nov 2007 15:15:54 -0000	1.58
+++ target-sparc/cpu.h	20 Nov 2007 01:23:33 -0000
@@ -215,7 +215,7 @@ typedef struct CPUSPARCState {
     uint64_t dtlb_tag[64];
     uint64_t dtlb_tte[64];
 #else
-    uint32_t mmuregs[16];
+    uint32_t mmuregs[32];
     uint64_t mxccdata[4];
     uint64_t mxccregs[8];
 #endif
Index: target-sparc/op_helper.c
===================================================================
RCS file: /sources/qemu/qemu/target-sparc/op_helper.c,v
retrieving revision 1.57
diff -p -u -r1.57 op_helper.c
--- target-sparc/op_helper.c	19 Nov 2007 19:14:10 -0000	1.57
+++ target-sparc/op_helper.c	20 Nov 2007 01:23:33 -0000
@@ -248,11 +248,15 @@ void helper_ld_asi(int asi, int size, in
         break;
     case 4: /* read MMU regs */
         {
-            int reg = (T0 >> 8) & 0xf;
+            int reg = (T0 >> 8) & 0x1f;
 
             ret = env->mmuregs[reg];
             if (reg == 3) /* Fault status cleared on read */
-                env->mmuregs[reg] = 0;
+                env->mmuregs[3] = 0;
+            else if (reg == 0x13) /* Fault status read */
+                ret = env->mmuregs[3];
+            else if (reg == 0x14) /* Fault address read */
+                ret = env->mmuregs[4];
             DPRINTF_MMU("mmu_read: reg[%d] = 0x%08x\n", reg, ret);
         }
         break;
@@ -493,17 +497,18 @@ void helper_st_asi(int asi, int size)
         }
     case 4: /* write MMU regs */
         {
-            int reg = (T0 >> 8) & 0xf;
+            int reg = (T0 >> 8) & 0x1f;
             uint32_t oldreg;
 
             oldreg = env->mmuregs[reg];
             switch(reg) {
             case 0:
-                env->mmuregs[reg] &= ~(MMU_E | MMU_NF | env->mmu_bm);
-                env->mmuregs[reg] |= T1 & (MMU_E | MMU_NF | env->mmu_bm);
+                env->mmuregs[reg] = (env->mmuregs[reg] & 0xff000000) |
+                                    (T1 & 0x00ffffff);
                 // Mappings generated during no-fault mode or MMU
                 // disabled mode are invalid in normal mode
-                if (oldreg != env->mmuregs[reg])
+                if ((oldreg & (MMU_E | MMU_NF | env->mmu_bm)) != 
+                    (env->mmuregs[reg] & (MMU_E | MMU_NF | env->mmu_bm)))
                     tlb_flush(env, 1);
                 break;
             case 2:
@@ -517,6 +522,12 @@ void helper_st_asi(int asi, int size)
             case 3:
             case 4:
                 break;
+            case 0x13:
+                env->mmuregs[3] = T1;
+                break;
+            case 0x14:
+                env->mmuregs[4] = T1;
+                break;
             default:
                 env->mmuregs[reg] = T1;
                 break;