target/riscv: Implement address masking functions required for RISC-V Pointer Masking extension

Signed-off-by: Anatoly Parshintsev <kupokupokupopo@gmail.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20211025173609.2724490-8-space.monkey.delivers@gmail.com
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/cpu.h

@@ -410,6 +410,8 @@ FIELD(TB_FLAGS, HLSX, 10, 1)
 FIELD(TB_FLAGS, MSTATUS_HS_FS, 11, 2)
 /* The combination of MXL/SXL/UXL that applies to the current cpu mode. */
 FIELD(TB_FLAGS, XL, 13, 2)
+/* If PointerMasking should be applied */
+FIELD(TB_FLAGS, PM_ENABLED, 15, 1)
 
 #ifdef TARGET_RISCV32
 #define riscv_cpu_mxl(env)  ((void)(env), MXL_RV32)

target/riscv/cpu_helper.c

@@ -107,6 +107,24 @@ void cpu_get_tb_cpu_state(CPURISCVState *env, target_ulong *pc,
         flags = FIELD_DP32(flags, TB_FLAGS, MSTATUS_HS_FS,
                            get_field(env->mstatus_hs, MSTATUS_FS));
     }
+    if (riscv_has_ext(env, RVJ)) {
+        int priv = flags & TB_FLAGS_PRIV_MMU_MASK;
+        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
 
     flags = FIELD_DP32(flags, TB_FLAGS, XL, cpu_get_xl(env));

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"
 
@@ -83,6 +86,10 @@ typedef struct DisasContext {
     TCGv zero;
     /* Space for 3 operands plus 1 extra for address computation. */
     TCGv temp[4];
+    /* PointerMasking extension */
+    bool pm_enabled;
+    TCGv pm_mask;
+    TCGv pm_base;
 } DisasContext;
 
 static inline bool has_ext(DisasContext *ctx, uint32_t ext)
@@ -272,11 +279,20 @@ static void gen_jal(DisasContext *ctx, int rd, target_ulong imm)
 }
 
 /*
- * Temp stub: generates address adjustment for PointerMasking
+ * Generates address adjustment for PointerMasking
  */
 static TCGv gen_pm_adjust_address(DisasContext *s, TCGv src)
 {
-    return src;
+    TCGv temp;
+    if (!s->pm_enabled) {
+        /* Load unmodified address */
+        return src;
+    } else {
+        temp = temp_new(s);
+        tcg_gen_andc_tl(temp, src, s->pm_mask);
+        tcg_gen_or_tl(temp, temp, s->pm_base);
+        return temp;
+    }
 }
 
 #ifndef CONFIG_USER_ONLY
@@ -622,6 +638,10 @@ static void riscv_tr_init_disas_context(DisasContextBase *dcbase, CPUState *cs)
     ctx->cs = cs;
     ctx->ntemp = 0;
     memset(ctx->temp, 0, sizeof(ctx->temp));
+    ctx->pm_enabled = FIELD_EX32(tb_flags, TB_FLAGS, PM_ENABLED);
+    int priv = tb_flags & TB_FLAGS_PRIV_MMU_MASK;
+    ctx->pm_mask = pm_mask[priv];
+    ctx->pm_base = pm_base[priv];
 
     ctx->zero = tcg_constant_tl(0);
 }
@@ -735,4 +755,19 @@ void riscv_translate_init(void)
                              "load_res");
     load_val = tcg_global_mem_new(cpu_env, offsetof(CPURISCVState, load_val),
                              "load_val");
+#ifndef CONFIG_USER_ONLY
+    /* 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");
+#endif
 }