target/mips: Weaken TLB flush on UX,SX,KX,ASID changes

There is no need to invalidate any shadow TLB entries when the ASID
changes or when access to one of the 64-bit segments has been disabled,
since doing so doesn't reveal to software whether any TLB entries have
been evicted into the shadow half of the TLB.

Therefore weaken the tlb flushes in these cases to only flush the QEMU
TLB.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Yongbok Kim <yongbok.kim@imgtec.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Tested-by: NYongbok Kim <yongbok.kim@imgtec.com>
Signed-off-by: NYongbok Kim <yongbok.kim@imgtec.com>

target/mips/helper.c

@@ -290,7 +290,7 @@ void cpu_mips_store_status(CPUMIPSState *env, target_ulong val)
 #if defined(TARGET_MIPS64)
     if ((env->CP0_Status ^ old) & (old & (7 << CP0St_UX))) {
         /* Access to at least one of the 64-bit segments has been disabled */
-        cpu_mips_tlb_flush(env);
+        tlb_flush(CPU(mips_env_get_cpu(env)));
     }
 #endif
     if (env->CP0_Config3 & (1 << CP0C3_MT)) {

target/mips/op_helper.c

@@ -1416,7 +1416,7 @@ void helper_mtc0_entryhi(CPUMIPSState *env, target_ulong arg1)
     /* If the ASID changes, flush qemu's TLB.  */
     if ((old & env->CP0_EntryHi_ASID_mask) !=
         (val & env->CP0_EntryHi_ASID_mask)) {
-        cpu_mips_tlb_flush(env);
+        tlb_flush(CPU(mips_env_get_cpu(env)));
     }
 }