[PATCH v4 5/5] [RISCV_PM] Implement address masking functions required for RISC-V Pointer Masking extension

[Alexey Baturo <baturo.alexey@gmail.com>]

From: Anatoly Parshintsev <kupokupokupopo@gmail.com>

Signed-off-by: Anatoly Parshintsev <kupokupokupopo@gmail.com>
---
 target/riscv/cpu.h       | 19 +++++++++++++++++++
 target/riscv/translate.c | 34 ++++++++++++++++++++++++++++++++--
 2 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index c236f01fff..13accaa232 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -386,6 +386,7 @@ FIELD(TB_FLAGS, VL_EQ_VLMAX, 2, 1)
 FIELD(TB_FLAGS, LMUL, 3, 2)
 FIELD(TB_FLAGS, SEW, 5, 3)
 FIELD(TB_FLAGS, VILL, 8, 1)
+FIELD(TB_FLAGS, PM_ENABLED, 9, 1)
 
 /*
  * A simplification for VLMAX
@@ -432,6 +433,24 @@ static inline void cpu_get_tb_cpu_state(CPURISCVState *env, target_ulong *pc,
     if (riscv_cpu_fp_enabled(env)) {
         flags |= env->mstatus & MSTATUS_FS;
     }
+    if (riscv_has_ext(env, RVJ)) {
+        int priv = cpu_mmu_index(env, false);
+        bool pm_enabled = false;
+        switch (priv) {
+        case PRV_U:
+            pm_enabled = env->mmte & U_PM_ENABLE;
+            break;
+        case PRV_S:
+            pm_enabled = env->mmte & S_PM_ENABLE;
+            break;
+        case PRV_M:
+            pm_enabled = env->mmte & M_PM_ENABLE;
+            break;
+        default:
+            g_assert_not_reached();
+        }
+        flags = FIELD_DP32(flags, TB_FLAGS, PM_ENABLED, pm_enabled);
+    }
 #endif
     *pflags = flags;
 }
diff --git a/target/riscv/translate.c b/target/riscv/translate.c
index a7cbf909f3..b3e7b93bc9 100644
--- a/target/riscv/translate.c
+++ b/target/riscv/translate.c
@@ -36,6 +36,9 @@ static TCGv cpu_gpr[32], cpu_pc, cpu_vl;
 static TCGv_i64 cpu_fpr[32]; /* assume F and D extensions */
 static TCGv load_res;
 static TCGv load_val;
+/* globals for PM CSRs */
+static TCGv pm_mask[4];
+static TCGv pm_base[4];
 
 #include "exec/gen-icount.h"
 
@@ -63,6 +66,10 @@ typedef struct DisasContext {
     uint16_t vlen;
     uint16_t mlen;
     bool vl_eq_vlmax;
+    /* PointerMasking extension */
+    bool pm_enabled;
+    TCGv pm_mask;
+    TCGv pm_base;
 } DisasContext;
 
 #ifdef TARGET_RISCV64
@@ -102,13 +109,19 @@ static void gen_nanbox_s(TCGv_i64 out, TCGv_i64 in)
 }
 
 /*
- * Temp stub: generates address adjustment for PointerMasking
+ * Generates address adjustment for PointerMasking
  */
 static void gen_pm_adjust_address(DisasContext *s,
                                   TCGv_i64      dst,
                                   TCGv_i64      src)
 {
-    tcg_gen_mov_i64(dst, src);
+    if (!s->pm_enabled) {
+        /* Load unmodified address */
+        tcg_gen_mov_i64(dst, src);
+    } else {
+        tcg_gen_andc_i64(dst, src, s->pm_mask);
+        tcg_gen_or_i64(dst, dst, s->pm_base);
+    }
 }
 
 /*
@@ -826,6 +839,10 @@ static void riscv_tr_init_disas_context(DisasContextBase *dcbase, CPUState *cs)
     ctx->lmul = FIELD_EX32(tb_flags, TB_FLAGS, LMUL);
     ctx->mlen = 1 << (ctx->sew  + 3 - ctx->lmul);
     ctx->vl_eq_vlmax = FIELD_EX32(tb_flags, TB_FLAGS, VL_EQ_VLMAX);
+    ctx->pm_enabled = FIELD_EX32(tb_flags, TB_FLAGS, PM_ENABLED);
+    int priv = cpu_mmu_index(env, false);
+    ctx->pm_mask = pm_mask[priv];
+    ctx->pm_base = pm_base[priv];
 }
 
 static void riscv_tr_tb_start(DisasContextBase *db, CPUState *cpu)
@@ -945,4 +962,17 @@ void riscv_translate_init(void)
                              "load_res");
     load_val = tcg_global_mem_new(cpu_env, offsetof(CPURISCVState, load_val),
                              "load_val");
+    /* Assign PM CSRs to tcg globals */
+    pm_mask[PRV_U] =
+      tcg_global_mem_new(cpu_env, offsetof(CPURISCVState, upmmask), "upmmask");
+    pm_base[PRV_U] =
+      tcg_global_mem_new(cpu_env, offsetof(CPURISCVState, upmbase), "upmbase");
+    pm_mask[PRV_S] =
+      tcg_global_mem_new(cpu_env, offsetof(CPURISCVState, spmmask), "spmmask");
+    pm_base[PRV_S] =
+      tcg_global_mem_new(cpu_env, offsetof(CPURISCVState, spmbase), "spmbase");
+    pm_mask[PRV_M] =
+      tcg_global_mem_new(cpu_env, offsetof(CPURISCVState, mpmmask), "mpmmask");
+    pm_base[PRV_M] =
+      tcg_global_mem_new(cpu_env, offsetof(CPURISCVState, mpmbase), "mpmbase");
 }
-- 
2.20.1