target-mips: add CP0.PageGrain.ELPA support

CP0.PageGrain.ELPA enables support for large physical addresses. This field
is encoded as follows:
0: Large physical address support is disabled.
1: Large physical address support is enabled.

If this bit is a 1, the following changes occur to coprocessor 0 registers:
- The PFNX field of the EntryLo0 and EntryLo1 registers is writable and
  concatenated with the PFN field to form the full page frame number.
- Access to optional COP0 registers with PA extension, LLAddr, TagLo is
  defined.

P5600 can operate in 32-bit or 40-bit Physical Address Mode. Therefore if
XPA is disabled (CP0.PageGrain.ELPA = 0) then assume 32-bit Address Mode.
In MIPS64 assume 36 as default PABITS (when CP0.PageGrain.ELPA = 0).

env->PABITS value is constant and indicates maximum PABITS available on
a core, whereas env->PAMask is calculated from env->PABITS and is also
affected by CP0.PageGrain.ELPA.

Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>

1 files changed, 12 insertions, 7 deletions

diff --git a/target-mips/op_helper.c b/target-mips/op_helper.c
index 31bafcf954..2a9ddff70f 100644
--- a/target-mips/op_helper.c
+++ b/target-mips/op_helper.c
@@ -1068,19 +1068,23 @@ void helper_mtc0_vpeopt(CPUMIPSState *env, target_ulong arg1)
     env->CP0_VPEOpt = arg1 & 0x0000ffff;
 }
 
+#define MTC0_ENTRYLO_MASK(env) ((env->PAMask >> 6) & 0x3FFFFFFF)
+
 void helper_mtc0_entrylo0(CPUMIPSState *env, target_ulong arg1)
 {
-    /* Large physaddr (PABITS) not implemented */
     /* 1k pages not implemented */
     target_ulong rxi = arg1 & (env->CP0_PageGrain & (3u << CP0PG_XIE));
-    env->CP0_EntryLo0 = (arg1 & 0x3FFFFFFF) | (rxi << (CP0EnLo_XI - 30));
+    env->CP0_EntryLo0 = (arg1 & MTC0_ENTRYLO_MASK(env))
+                        | (rxi << (CP0EnLo_XI - 30));
 }
 
 #if defined(TARGET_MIPS64)
+#define DMTC0_ENTRYLO_MASK(env) (env->PAMask >> 6)
+
 void helper_dmtc0_entrylo0(CPUMIPSState *env, uint64_t arg1)
 {
     uint64_t rxi = arg1 & ((env->CP0_PageGrain & (3ull << CP0PG_XIE)) << 32);
-    env->CP0_EntryLo0 = (arg1 & 0x3FFFFFFF) | rxi;
+    env->CP0_EntryLo0 = (arg1 & DMTC0_ENTRYLO_MASK(env)) | rxi;
 }
 #endif
 
@@ -1246,17 +1250,17 @@ void helper_mttc0_tcschefback(CPUMIPSState *env, target_ulong arg1)
 
 void helper_mtc0_entrylo1(CPUMIPSState *env, target_ulong arg1)
 {
-    /* Large physaddr (PABITS) not implemented */
     /* 1k pages not implemented */
     target_ulong rxi = arg1 & (env->CP0_PageGrain & (3u << CP0PG_XIE));
-    env->CP0_EntryLo1 = (arg1 & 0x3FFFFFFF) | (rxi << (CP0EnLo_XI - 30));
+    env->CP0_EntryLo1 = (arg1 & MTC0_ENTRYLO_MASK(env))
+                        | (rxi << (CP0EnLo_XI - 30));
 }
 
 #if defined(TARGET_MIPS64)
 void helper_dmtc0_entrylo1(CPUMIPSState *env, uint64_t arg1)
 {
     uint64_t rxi = arg1 & ((env->CP0_PageGrain & (3ull << CP0PG_XIE)) << 32);
-    env->CP0_EntryLo1 = (arg1 & 0x3FFFFFFF) | rxi;
+    env->CP0_EntryLo1 = (arg1 & DMTC0_ENTRYLO_MASK(env)) | rxi;
 }
 #endif
 
@@ -1279,10 +1283,11 @@ void helper_mtc0_pagemask(CPUMIPSState *env, target_ulong arg1)
 void helper_mtc0_pagegrain(CPUMIPSState *env, target_ulong arg1)
 {
     /* SmartMIPS not implemented */
-    /* Large physaddr (PABITS) not implemented */
     /* 1k pages not implemented */
     env->CP0_PageGrain = (arg1 & env->CP0_PageGrain_rw_bitmask) |
                          (env->CP0_PageGrain & ~env->CP0_PageGrain_rw_bitmask);
+    compute_hflags(env);
+    restore_pamask(env);
 }
 
 void helper_mtc0_wired(CPUMIPSState *env, target_ulong arg1)