[Qemu-devel] [PULL 19/27] target/mips: Add CP0 PWBase register

[Aleksandar Markovic <aleksandar.markovic@rt-rk.com>]

From: Yongbok Kim <yongbok.kim@mips.com>

Add PWBase register (CP0 Register 5, Select 5).

The PWBase register contains the Page Table Base virtual address.

This register is required for the hardware page walker feature. It
exists only if Config3 PW bit is set to 1.

Reviewed-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Signed-off-by: Yongbok Kim <yongbok.kim@mips.com>
Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>
---
 target/mips/cpu.h       |  1 +
 target/mips/machine.c   |  5 +++--
 target/mips/translate.c | 31 +++++++++++++++++++++++++++++++
 3 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/target/mips/cpu.h b/target/mips/cpu.h
index 953643b..9cbde99 100644
--- a/target/mips/cpu.h
+++ b/target/mips/cpu.h
@@ -416,6 +416,7 @@ struct CPUMIPSState {
 #define CP0SC2_XR       56
 #define CP0SC2_XR_MASK  (0xFFULL << CP0SC2_XR)
 #define CP0SC2_MASK     (CP0SC_1GMASK | (CP0SC_1GMASK << 16) | CP0SC2_XR_MASK)
+    target_ulong CP0_PWBase;
 /*
  * CP0 Register 6
  */
diff --git a/target/mips/machine.c b/target/mips/machine.c
index 5ba78ac..3592bb7 100644
--- a/target/mips/machine.c
+++ b/target/mips/machine.c
@@ -212,8 +212,8 @@ const VMStateDescription vmstate_tlb = {
 
 const VMStateDescription vmstate_mips_cpu = {
     .name = "cpu",
-    .version_id = 11,
-    .minimum_version_id = 11,
+    .version_id = 12,
+    .minimum_version_id = 12,
     .post_load = cpu_post_load,
     .fields = (VMStateField[]) {
         /* Active TC */
@@ -256,6 +256,7 @@ const VMStateDescription vmstate_mips_cpu = {
         VMSTATE_UINTTL(env.CP0_SegCtl0, MIPSCPU),
         VMSTATE_UINTTL(env.CP0_SegCtl1, MIPSCPU),
         VMSTATE_UINTTL(env.CP0_SegCtl2, MIPSCPU),
+        VMSTATE_UINTTL(env.CP0_PWBase, MIPSCPU),
         VMSTATE_INT32(env.CP0_Wired, MIPSCPU),
         VMSTATE_INT32(env.CP0_SRSConf0, MIPSCPU),
         VMSTATE_INT32(env.CP0_SRSConf1, MIPSCPU),
diff --git a/target/mips/translate.c b/target/mips/translate.c
index b35e7d3..e166963 100644
--- a/target/mips/translate.c
+++ b/target/mips/translate.c
@@ -2481,6 +2481,17 @@ static inline void check_xnp(DisasContext *ctx)
 
 /*
  * This code generates a "reserved instruction" exception if the
+ * Config3 PW bit is NOT set.
+ */
+static inline void check_pw(DisasContext *ctx)
+{
+    if (unlikely(!(ctx->CP0_Config3 & (1 << CP0C3_PW)))) {
+        generate_exception_end(ctx, EXCP_RI);
+    }
+}
+
+/*
+ * This code generates a "reserved instruction" exception if the
  * Config3 MT bit is NOT set.
  */
 static inline void check_mt(DisasContext *ctx)
@@ -6089,6 +6100,11 @@ static void gen_mfc0(DisasContext *ctx, TCGv arg, int reg, int sel)
             tcg_gen_ext32s_tl(arg, arg);
             rn = "SegCtl2";
             break;
+        case 5:
+            check_pw(ctx);
+            gen_mfc0_load32(arg, offsetof(CPUMIPSState, CP0_PWBase));
+            rn = "PWBase";
+            break;
         default:
             goto cp0_unimplemented;
         }
@@ -6790,6 +6806,11 @@ static void gen_mtc0(DisasContext *ctx, TCGv arg, int reg, int sel)
             gen_helper_mtc0_segctl2(cpu_env, arg);
             rn = "SegCtl2";
             break;
+        case 5:
+            check_pw(ctx);
+            gen_mtc0_store32(arg, offsetof(CPUMIPSState, CP0_PWBase));
+            rn = "PWBase";
+            break;
         default:
             goto cp0_unimplemented;
         }
@@ -7500,6 +7521,11 @@ static void gen_dmfc0(DisasContext *ctx, TCGv arg, int reg, int sel)
             tcg_gen_ld_tl(arg, cpu_env, offsetof(CPUMIPSState, CP0_SegCtl2));
             rn = "SegCtl2";
             break;
+        case 5:
+            check_pw(ctx);
+            tcg_gen_ld_tl(arg, cpu_env, offsetof(CPUMIPSState, CP0_PWBase));
+            rn = "PWBase";
+            break;
         default:
             goto cp0_unimplemented;
         }
@@ -8183,6 +8209,11 @@ static void gen_dmtc0(DisasContext *ctx, TCGv arg, int reg, int sel)
             gen_helper_mtc0_segctl2(cpu_env, arg);
             rn = "SegCtl2";
             break;
+        case 5:
+            check_pw(ctx);
+            tcg_gen_st_tl(arg, cpu_env, offsetof(CPUMIPSState, CP0_PWBase));
+            rn = "PWBase";
+            break;
         default:
             goto cp0_unimplemented;
         }
-- 
2.7.4