[Qemu-devel] [PATCH] target-mips: add MAAR, MAARI register

[Yongbok Kim]

The MAAR register is a read/write register included in Release 5
of the architecture that defines the accessibility attributes of
physical address regions. In particular, MAAR defines whether an
instruction fetch or data load can speculatively access a memory
region within the physical address bounds specified by MAAR.

As QEMU doesn't do speculative access, hence this patch only
provides ability to access the registers.

Signed-off-by: Yongbok Kim <address@hidden>
---
 target-mips/cpu.h       |    4 +++
 target-mips/helper.h    |    6 +++++
 target-mips/machine.c   |    3 ++
 target-mips/op_helper.c |   56 +++++++++++++++++++++++++++++++++++++++++++++++
 target-mips/translate.c |   56 +++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 125 insertions(+), 0 deletions(-)

diff --git a/target-mips/cpu.h b/target-mips/cpu.h
index bd23c2a..39e2129 100644
--- a/target-mips/cpu.h
+++ b/target-mips/cpu.h
@@ -162,6 +162,7 @@ typedef struct mips_def_t mips_def_t;
 #define MIPS_FPU_MAX 1
 #define MIPS_DSP_ACC 4
 #define MIPS_KSCRATCH_NUM 6
+#define MIPS_MAAR_MAX 16 /* Must be an even number. */
 
 typedef struct TCState TCState;
 struct TCState {
@@ -474,10 +475,13 @@ struct CPUMIPSState {
 #define CP0C5_SBRI       6
 #define CP0C5_MVH        5
 #define CP0C5_LLB        4
+#define CP0C5_MRP        3
 #define CP0C5_UFR        2
 #define CP0C5_NFExists   0
     int32_t CP0_Config6;
     int32_t CP0_Config7;
+    uint64_t CP0_MAAR[MIPS_MAAR_MAX];
+    int32_t CP0_MAARI;
     /* XXX: Maybe make LLAddr per-TC? */
     uint64_t lladdr;
     target_ulong llval;
diff --git a/target-mips/helper.h b/target-mips/helper.h
index 95b9149..8bd39c2 100644
--- a/target-mips/helper.h
+++ b/target-mips/helper.h
@@ -77,6 +77,8 @@ DEF_HELPER_1(mftc0_epc, tl, env)
 DEF_HELPER_1(mftc0_ebase, tl, env)
 DEF_HELPER_2(mftc0_configx, tl, env, tl)
 DEF_HELPER_1(mfc0_lladdr, tl, env)
+DEF_HELPER_1(mfc0_maar, tl, env)
+DEF_HELPER_1(mfhc0_maar, tl, env)
 DEF_HELPER_2(mfc0_watchlo, tl, env, i32)
 DEF_HELPER_2(mfc0_watchhi, tl, env, i32)
 DEF_HELPER_1(mfc0_debug, tl, env)
@@ -88,6 +90,7 @@ DEF_HELPER_1(dmfc0_tccontext, tl, env)
 DEF_HELPER_1(dmfc0_tcschedule, tl, env)
 DEF_HELPER_1(dmfc0_tcschefback, tl, env)
 DEF_HELPER_1(dmfc0_lladdr, tl, env)
+DEF_HELPER_1(dmfc0_maar, tl, env)
 DEF_HELPER_2(dmfc0_watchlo, tl, env, i32)
 #endif /* TARGET_MIPS64 */
 
@@ -144,6 +147,9 @@ DEF_HELPER_2(mtc0_config3, void, env, tl)
 DEF_HELPER_2(mtc0_config4, void, env, tl)
 DEF_HELPER_2(mtc0_config5, void, env, tl)
 DEF_HELPER_2(mtc0_lladdr, void, env, tl)
+DEF_HELPER_2(mtc0_maar, void, env, tl)
+DEF_HELPER_2(mthc0_maar, void, env, tl)
+DEF_HELPER_2(mtc0_maari, void, env, tl)
 DEF_HELPER_3(mtc0_watchlo, void, env, tl, i32)
 DEF_HELPER_3(mtc0_watchhi, void, env, tl, i32)
 DEF_HELPER_2(mtc0_xcontext, void, env, tl)
diff --git a/target-mips/machine.c b/target-mips/machine.c
index 737f3c2..667bde4 100644
--- a/target-mips/machine.c
+++ b/target-mips/machine.c
@@ -272,6 +272,8 @@ const VMStateDescription vmstate_mips_cpu = {
         VMSTATE_INT32(env.CP0_Config3, MIPSCPU),
         VMSTATE_INT32(env.CP0_Config6, MIPSCPU),
         VMSTATE_INT32(env.CP0_Config7, MIPSCPU),
+        VMSTATE_UINT64_ARRAY(env.CP0_MAAR, MIPSCPU, MIPS_MAAR_MAX),
+        VMSTATE_INT32(env.CP0_MAARI, MIPSCPU),
         VMSTATE_UINT64(env.lladdr, MIPSCPU),
         VMSTATE_UINTTL_ARRAY(env.CP0_WatchLo, MIPSCPU, 8),
         VMSTATE_INT32_ARRAY(env.CP0_WatchHi, MIPSCPU, 8),
@@ -297,3 +299,4 @@ const VMStateDescription vmstate_mips_cpu = {
         VMSTATE_END_OF_LIST()
     },
 };
+
diff --git a/target-mips/op_helper.c b/target-mips/op_helper.c
index 684ec92..13aac92 100644
--- a/target-mips/op_helper.c
+++ b/target-mips/op_helper.c
@@ -881,6 +881,22 @@ target_ulong helper_mfc0_lladdr(CPUMIPSState *env)
     return (int32_t)(env->lladdr >> env->CP0_LLAddr_shift);
 }
 
+target_ulong helper_mfc0_maar(CPUMIPSState *env)
+{
+    if (env->CP0_MAARI < MIPS_MAAR_MAX) {
+        return (int32_t) env->CP0_MAAR[env->CP0_MAARI];
+    }
+    return 0;
+}
+
+target_ulong helper_mfhc0_maar(CPUMIPSState *env)
+{
+    if (env->CP0_MAARI < MIPS_MAAR_MAX) {
+        return env->CP0_MAAR[env->CP0_MAARI] >> 32;
+    }
+    return 0;
+}
+
 target_ulong helper_mfc0_watchlo(CPUMIPSState *env, uint32_t sel)
 {
     return (int32_t)env->CP0_WatchLo[sel];
@@ -947,6 +963,14 @@ target_ulong helper_dmfc0_lladdr(CPUMIPSState *env)
     return env->lladdr >> env->CP0_LLAddr_shift;
 }
 
+target_ulong helper_dmfc0_maar(CPUMIPSState *env)
+{
+    if (env->CP0_MAARI < MIPS_MAAR_MAX) {
+        return env->CP0_MAAR[env->CP0_MAARI];
+    }
+    return 0;
+}
+
 target_ulong helper_dmfc0_watchlo(CPUMIPSState *env, uint32_t sel)
 {
     return env->CP0_WatchLo[sel];
@@ -1570,6 +1594,38 @@ void helper_mtc0_lladdr(CPUMIPSState *env, target_ulong 
arg1)
     env->lladdr = (env->lladdr & ~mask) | (arg1 & mask);
 }
 
+void helper_mtc0_maar(CPUMIPSState *env, target_ulong arg1)
+{
+    uint64_t mask = ((env->PAMask >> 4) & ~0xFFFull) | 0x3;
+
+    if (env->CP0_MAARI < MIPS_MAAR_MAX) {
+        env->CP0_MAAR[env->CP0_MAARI] = arg1 & mask;
+    }
+}
+
+void helper_mthc0_maar(CPUMIPSState *env, target_ulong arg1)
+{
+    if (env->CP0_MAARI < MIPS_MAAR_MAX) {
+        env->CP0_MAAR[env->CP0_MAARI] = ((uint64_t) arg1 << 32) |
+                (env->CP0_MAAR[env->CP0_MAARI] & 0x00000000ffffffffULL);
+    }
+}
+
+void helper_mtc0_maari(CPUMIPSState *env, target_ulong arg1)
+{
+    int index = arg1 & 0x3f;
+    if (index == 0x3f) {
+        /* Software may write all ones to INDEX to determine the
+           maximum value supported. */
+        env->CP0_MAARI = MIPS_MAAR_MAX - 1;
+    } else if (index < MIPS_MAAR_MAX) {
+        env->CP0_MAARI = index;
+    }
+    /* Other than the all ones, if the
+       value written is not supported, then INDEX is unchanged
+       from its previous value. */
+}
+
 void helper_mtc0_watchlo(CPUMIPSState *env, target_ulong arg1, uint32_t sel)
 {
     /* Watch exceptions for instructions, data loads, data stores
diff --git a/target-mips/translate.c b/target-mips/translate.c
index 658926d..70990d4 100644
--- a/target-mips/translate.c
+++ b/target-mips/translate.c
@@ -1429,6 +1429,7 @@ typedef struct DisasContext {
     bool mvh;
     int CP0_LLAddr_shift;
     bool ps;
+    bool mrp;
 } DisasContext;
 
 enum {
@@ -4807,6 +4808,13 @@ static void gen_mfhc0(DisasContext *ctx, TCGv arg, int 
reg, int sel)
                              ctx->CP0_LLAddr_shift);
             rn = "LLAddr";
             break;
+        case 1:
+            if (!ctx->mrp) {
+                goto mfhc0_read_zero;
+            }
+            gen_helper_mfhc0_maar(arg, cpu_env);
+            rn = "MAAR";
+            break;
         default:
             goto mfhc0_read_zero;
         }
@@ -4878,6 +4886,13 @@ static void gen_mthc0(DisasContext *ctx, TCGv arg, int 
reg, int sel)
                treating MTHC0 to LLAddr as NOP. */
             rn = "LLAddr";
             break;
+        case 1:
+            if (!ctx->mrp) {
+                goto mthc0_nop;
+            }
+            gen_helper_mthc0_maar(cpu_env, arg);
+            rn = "MAAR";
+            break;
         default:
             goto mthc0_nop;
         }
@@ -5334,6 +5349,16 @@ static void gen_mfc0(DisasContext *ctx, TCGv arg, int 
reg, int sel)
             gen_helper_mfc0_lladdr(arg, cpu_env);
             rn = "LLAddr";
             break;
+        case 1:
+            CP0_CHECK(ctx->mrp);
+            gen_helper_mfc0_maar(arg, cpu_env);
+            rn = "MAAR";
+            break;
+        case 2:
+            CP0_CHECK(ctx->mrp);
+            gen_mfc0_load32(arg, offsetof(CPUMIPSState, CP0_MAARI));
+            rn = "MAARI";
+            break;
         default:
             goto cp0_unimplemented;
         }
@@ -5963,6 +5988,16 @@ static void gen_mtc0(DisasContext *ctx, TCGv arg, int 
reg, int sel)
             gen_helper_mtc0_lladdr(cpu_env, arg);
             rn = "LLAddr";
             break;
+        case 1:
+            CP0_CHECK(ctx->mrp);
+            gen_helper_mtc0_maar(cpu_env, arg);
+            rn = "MAAR";
+            break;
+        case 2:
+            CP0_CHECK(ctx->mrp);
+            gen_helper_mtc0_maari(cpu_env, arg);
+            rn = "MAARI";
+            break;
         default:
             goto cp0_unimplemented;
         }
@@ -6588,6 +6623,16 @@ static void gen_dmfc0(DisasContext *ctx, TCGv arg, int 
reg, int sel)
             gen_helper_dmfc0_lladdr(arg, cpu_env);
             rn = "LLAddr";
             break;
+        case 1:
+            CP0_CHECK(ctx->mrp);
+            gen_helper_dmfc0_maar(arg, cpu_env);
+            rn = "MAAR";
+            break;
+        case 2:
+            CP0_CHECK(ctx->mrp);
+            gen_mfc0_load32(arg, offsetof(CPUMIPSState, CP0_MAARI));
+            rn = "MAARI";
+            break;
         default:
             goto cp0_unimplemented;
         }
@@ -7209,6 +7254,16 @@ static void gen_dmtc0(DisasContext *ctx, TCGv arg, int 
reg, int sel)
             gen_helper_mtc0_lladdr(cpu_env, arg);
             rn = "LLAddr";
             break;
+        case 1:
+            CP0_CHECK(ctx->mrp);
+            gen_helper_mtc0_maar(cpu_env, arg);
+            rn = "MAAR";
+            break;
+        case 2:
+            CP0_CHECK(ctx->mrp);
+            gen_helper_mtc0_maari(cpu_env, arg);
+            rn = "MAARI";
+            break;
         default:
             goto cp0_unimplemented;
         }
@@ -19611,6 +19666,7 @@ void gen_intermediate_code(CPUMIPSState *env, struct 
TranslationBlock *tb)
     ctx.ulri = (env->CP0_Config3 >> CP0C3_ULRI) & 1;
     ctx.ps = ((env->active_fpu.fcr0 >> FCR0_PS) & 1) ||
              (env->insn_flags & (INSN_LOONGSON2E | INSN_LOONGSON2F));
+    ctx.mrp = (env->CP0_Config5 >> CP0C5_MRP) & 1;
     restore_cpu_state(env, &ctx);
 #ifdef CONFIG_USER_ONLY
         ctx.mem_idx = MIPS_HFLAG_UM;
-- 
1.7.1