[PATCH v12 6/7] [RISCV_PM] Implement address masking functions required for RISC-V Pointer Masking extension

[Alexey Baturo]

From: Anatoly Parshintsev <kupokupokupopo@gmail.com>

Signed-off-by: Anatoly Parshintsev <kupokupokupopo@gmail.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
---
 target/riscv/cpu.h       | 20 ++++++++++++++
 target/riscv/translate.c | 56 +++++++++++++++++++++++++++++++++-------
 2 files changed, 66 insertions(+), 10 deletions(-)

diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index c41a937a80..a7496d9a56 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -405,6 +405,8 @@ FIELD(TB_FLAGS, SEW, 5, 3)
 FIELD(TB_FLAGS, VILL, 8, 1)
 /* Is a Hypervisor instruction load/store allowed? */
 FIELD(TB_FLAGS, HLSX, 9, 1)
+/* If PointerMasking should be applied */
+FIELD(TB_FLAGS, PM_ENABLED, 10, 1)
 
 bool riscv_cpu_is_32bit(CPURISCVState *env);
 
@@ -462,6 +464,24 @@ static inline void cpu_get_tb_cpu_state(CPURISCVState 
*env, target_ulong *pc,
             flags = FIELD_DP32(flags, TB_FLAGS, HLSX, 1);
         }
     }
+    if (riscv_has_ext(env, RVJ)) {
+        int priv = cpu_mmu_index(env, false) & 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
 
     *pflags = flags;
diff --git a/target/riscv/translate.c b/target/riscv/translate.c
index de4997a3e5..4618443524 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"
 
@@ -81,6 +84,10 @@ 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)
@@ -117,16 +124,6 @@ static void gen_nanbox_s(TCGv_i64 out, TCGv_i64 in)
     tcg_gen_ori_i64(out, in, MAKE_64BIT_MASK(32, 32));
 }
 
-/*
- * Temp stub: generates address adjustment for PointerMasking
- */
-static void gen_pm_adjust_address(DisasContext *s,
-                                  TCGv         *dst,
-                                  TCGv          src)
-{
-    tcg_gen_mov_tl(*dst, src);
-}
-
 /*
  * A narrow n-bit operation, where n < FLEN, checks that input operands
  * are correctly Nan-boxed, i.e., all upper FLEN - n bits are 1.
@@ -281,6 +278,26 @@ static void gen_jal(DisasContext *ctx, int rd, 
target_ulong imm)
     ctx->base.is_jmp = DISAS_NORETURN;
 }
 
+/*
+ * Generates address adjustment for PointerMasking
+ */
+static void gen_pm_adjust_address(DisasContext *s,
+                                  TCGv         *dst,
+                                  TCGv          src)
+{
+    TCGv temp;
+    if (!s->pm_enabled) {
+        /* Load unmodified address */
+        tcg_gen_mov_tl(*dst, src);
+    } else {
+        temp = temp_new(s);
+        tcg_gen_andc_tl(temp, src, s->pm_mask);
+        tcg_gen_or_tl(temp, temp, s->pm_base);
+        *dst = temp;
+    }
+}
+
+
 #ifndef CONFIG_USER_ONLY
 /* The states of mstatus_fs are:
  * 0 = disabled, 1 = initial, 2 = clean, 3 = dirty
@@ -553,6 +570,10 @@ static void riscv_tr_init_disas_context(DisasContextBase 
*dcbase, CPUState *cs)
     ctx->w = false;
     ctx->ntemp = 0;
     memset(ctx->temp, 0, sizeof(ctx->temp));
+    ctx->pm_enabled = FIELD_EX32(tb_flags, TB_FLAGS, PM_ENABLED);
+    int priv = cpu_mmu_index(env, false) & TB_FLAGS_PRIV_MMU_MASK;
+    ctx->pm_mask = pm_mask[priv];
+    ctx->pm_base = pm_base[priv];
 
     ctx->zero = tcg_constant_tl(0);
 }
@@ -666,4 +687,19 @@ 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
 }
-- 
2.30.2