[PATCH v2 2/5] [RISCV_PM] Support CSRs required for RISC-V PM extension except for ones in hypervisor mode

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

Signed-off-by: Alexey Baturo <space.monkey.delivers@gmail.com>
---
 target/riscv/cpu.c      |   1 +
 target/riscv/cpu.h      |  11 ++
 target/riscv/cpu_bits.h |  66 ++++++++++
 target/riscv/csr.c      | 277 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 355 insertions(+)

diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index fe6bab4a52..d63031eb08 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -440,6 +440,7 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp)
         }
         if (cpu->cfg.ext_j) {
             target_misa |= RVJ;
+            env->mmte |= PM_EXT_INITIAL;
         }
         if (cpu->cfg.ext_v) {
             target_misa |= RVV;
diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index eca611a367..21e47b8283 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -226,6 +226,17 @@ struct CPURISCVState {
 
     /* True if in debugger mode.  */
     bool debugger;
+
+    /* CSRs for PM
+     * TODO: move these csr to appropriate groups
+     */
+    target_ulong mmte;
+    target_ulong mpmmask;
+    target_ulong mpmbase;
+    target_ulong spmmask;
+    target_ulong spmbase;
+    target_ulong upmmask;
+    target_ulong upmbase;
 #endif
 
     float_status fp_status;
diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
index bd36062877..84c93c77ae 100644
--- a/target/riscv/cpu_bits.h
+++ b/target/riscv/cpu_bits.h
@@ -354,6 +354,21 @@
 #define CSR_MHPMCOUNTER30H  0xb9e
 #define CSR_MHPMCOUNTER31H  0xb9f
 
+/* Custom user register */
+#define CSR_UMTE            0x8c0
+#define CSR_UPMMASK         0x8c1
+#define CSR_UPMBASE         0x8c2
+
+/* Custom machine register */
+#define CSR_MMTE            0x7c0
+#define CSR_MPMMASK         0x7c1
+#define CSR_MPMBASE         0x7c2
+
+/* Custom supervisor register */
+#define CSR_SMTE            0x9c0
+#define CSR_SPMMASK         0x9c1
+#define CSR_SPMBASE         0x9c2
+
 /* Legacy Machine Protection and Translation (priv v1.9.1) */
 #define CSR_MBASE           0x380
 #define CSR_MBOUND          0x381
@@ -604,4 +619,55 @@
 #define MIE_UTIE                           (1 << IRQ_U_TIMER)
 #define MIE_SSIE                           (1 << IRQ_S_SOFT)
 #define MIE_USIE                           (1 << IRQ_U_SOFT)
+
+/* general mte CSR bits*/
+#define PM_ENABLE       0x00000001ULL
+#define PM_CURRENT      0x00000002ULL
+#define PM_XS_MASK      0x00000003ULL
+
+/* PM XS bits values */
+#define PM_EXT_DISABLE  0x00000000ULL
+#define PM_EXT_INITIAL  0x00000001ULL
+#define PM_EXT_CLEAN    0x00000002ULL
+#define PM_EXT_DIRTY    0x00000003ULL
+
+/* offsets for every pair of control bits per each priv level */
+#define XS_OFFSET    0ULL
+#define U_OFFSET     2ULL
+#define S_OFFSET     4ULL
+#define M_OFFSET     6ULL
+
+#define PM_XS_BITS   (PM_XS_MASK << XS_OFFSET)
+#define U_PM_ENABLE  (PM_ENABLE  << U_OFFSET)
+#define U_PM_CURRENT (PM_CURRENT << U_OFFSET)
+#define S_PM_ENABLE  (PM_ENABLE  << S_OFFSET)
+#define S_PM_CURRENT (PM_CURRENT << S_OFFSET)
+#define M_PM_ENABLE  (PM_ENABLE  << M_OFFSET)
+
+/* mmte CSR bits */
+#define MMTE_PM_XS_BITS     PM_XS_BITS
+#define MMTE_U_PM_ENABLE    U_PM_ENABLE
+#define MMTE_U_PM_CURRENT   U_PM_CURRENT
+#define MMTE_S_PM_ENABLE    S_PM_ENABLE
+#define MMTE_S_PM_CURRENT   S_PM_CURRENT
+#define MMTE_M_PM_ENABLE    M_PM_ENABLE
+#define MMTE_MASK           (MMTE_U_PM_ENABLE | MMTE_U_PM_CURRENT | \
+                             MMTE_S_PM_ENABLE | MMTE_S_PM_CURRENT | \
+                             MMTE_M_PM_ENABLE | MMTE_PM_XS_BITS)
+
+/* smte CSR bits */
+#define SMTE_PM_XS_BITS     PM_XS_BITS
+#define SMTE_U_PM_ENABLE    U_PM_ENABLE
+#define SMTE_U_PM_CURRENT   U_PM_CURRENT
+#define SMTE_S_PM_ENABLE    S_PM_ENABLE
+#define SMTE_S_PM_CURRENT   S_PM_CURRENT
+#define SMTE_MASK           (SMTE_U_PM_ENABLE | SMTE_U_PM_CURRENT | \
+                             SMTE_S_PM_ENABLE | SMTE_S_PM_CURRENT | \
+                             SMTE_PM_XS_BITS)
+
+/* umte CSR bits */
+#define UMTE_U_PM_ENABLE    U_PM_ENABLE
+#define UMTE_U_PM_CURRENT   U_PM_CURRENT
+#define UMTE_MASK           (UMTE_U_PM_ENABLE | MMTE_U_PM_CURRENT)
+
 #endif
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index aaef6c6f20..f48f4c4070 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -140,6 +140,11 @@ static int any(CPURISCVState *env, int csrno)
     return 0;
 }
 
+static int umode(CPURISCVState *env, int csrno)
+{
+    return -!riscv_has_ext(env, RVU);
+}
+
 static int smode(CPURISCVState *env, int csrno)
 {
     return -!riscv_has_ext(env, RVS);
@@ -1250,6 +1255,263 @@ static int write_pmpaddr(CPURISCVState *env, int csrno, target_ulong val)
     return 0;
 }
 
+/* Functions to access Pointer Masking feature registers 
+ * We have to check if current priv lvl could modify
+ * csr in given mode
+ */
+static int check_pm_current_disabled(CPURISCVState *env, int csrno)
+{
+    /* m-mode is always allowed to modify registers, so allow */
+    if (env->priv == PRV_M) {
+        return 0;
+    }
+    int csr_priv = get_field(csrno, 0xC00);
+    /* If priv lvls differ that means we're accessing csr from higher priv lvl, so allow */
+    if (env->priv != csr_priv) {
+        return 0;
+    }
+    int cur_bit_pos = (env->priv == PRV_U) ? U_PM_CURRENT :
+                      (env->priv == PRV_S) ? S_PM_CURRENT : -1;
+    assert(cur_bit_pos != -1);
+    int pm_current = get_field(env->mmte, cur_bit_pos);
+    /* We're in same priv lvl, so we allow to modify csr only if pm_current==1 */
+    return !pm_current;
+}
+
+static int read_mmte(CPURISCVState *env, int csrno, target_ulong *val)
+{
+#if !defined(CONFIG_USER_ONLY)
+    if (!riscv_has_ext(env, RVJ)) {
+        *val = 0;
+        return 0;
+    }
+#endif
+    *val = env->mmte & MMTE_MASK;
+    return 0;
+}
+
+static int write_mmte(CPURISCVState *env, int csrno, target_ulong val)
+{
+#if !defined(CONFIG_USER_ONLY)
+    if (!riscv_has_ext(env, RVJ)) {
+        return -RISCV_EXCP_ILLEGAL_INST;
+    }
+#endif
+    target_ulong wpri_val = val & MMTE_MASK;
+    assert(val == wpri_val);
+    env->mmte = val;
+    env->mstatus |= MSTATUS_XS | MSTATUS_SD;
+    env->mmte |= PM_EXT_DIRTY;
+    return 0;
+}
+
+static int read_smte(CPURISCVState *env, int csrno, target_ulong *val)
+{
+#if !defined(CONFIG_USER_ONLY)
+    if (!riscv_has_ext(env, RVJ)) {
+        *val = 0;
+        return 0;
+    }
+#endif
+    *val = env->mmte & SMTE_MASK;
+    return 0;
+}
+
+static int write_smte(CPURISCVState *env, int csrno, target_ulong val)
+{
+#if !defined(CONFIG_USER_ONLY)
+    if (!riscv_has_ext(env, RVJ)) {
+        return -RISCV_EXCP_ILLEGAL_INST;
+    }
+#endif
+    target_ulong wpri_val = val & SMTE_MASK;
+    assert(val == wpri_val);
+    if (check_pm_current_disabled(env, csrno))
+        return 0;
+    target_ulong new_val = val | (env->mmte & ~SMTE_MASK);
+    write_mmte(env, csrno, new_val);
+    return 0;
+}
+
+static int read_umte(CPURISCVState *env, int csrno, target_ulong *val)
+{
+#if !defined(CONFIG_USER_ONLY)
+    if (!riscv_has_ext(env, RVJ)) {
+        *val = 0;
+        return 0;
+    }
+#endif
+    *val = env->mmte & UMTE_MASK;
+    return 0;
+}
+
+static int write_umte(CPURISCVState *env, int csrno, target_ulong val)
+{
+#if !defined(CONFIG_USER_ONLY)
+    if (!riscv_has_ext(env, RVJ)) {
+        return -RISCV_EXCP_ILLEGAL_INST;
+    }
+#endif
+    target_ulong wpri_val = val & UMTE_MASK;
+    assert(val == wpri_val);
+    if (check_pm_current_disabled(env, csrno))
+        return 0;
+    target_ulong new_val = val | (env->mmte & ~UMTE_MASK);
+    write_mmte(env, csrno, new_val);
+    return 0;
+}
+
+static int read_mpmmask(CPURISCVState *env, int csrno, target_ulong *val)
+{
+#if !defined(CONFIG_USER_ONLY)
+    if (!riscv_has_ext(env, RVJ)) {
+        return -RISCV_EXCP_ILLEGAL_INST;
+    }
+#endif
+    *val = env->mpmmask;
+    return 0;
+}
+
+static int write_mpmmask(CPURISCVState *env, int csrno, target_ulong val)
+{
+#if !defined(CONFIG_USER_ONLY)
+    if (!riscv_has_ext(env, RVJ)) {
+        return -RISCV_EXCP_ILLEGAL_INST;
+    }
+#endif
+    env->mpmmask = val;
+    env->mstatus |= MSTATUS_XS | MSTATUS_SD;
+    env->mmte |= PM_EXT_DIRTY;
+    return 0;
+}
+
+static int read_spmmask(CPURISCVState *env, int csrno, target_ulong *val)
+{
+#if !defined(CONFIG_USER_ONLY)
+    if (!riscv_has_ext(env, RVJ)) {
+        return -RISCV_EXCP_ILLEGAL_INST;
+    }
+#endif
+    *val = env->spmmask;
+    return 0;
+}
+
+static int write_spmmask(CPURISCVState *env, int csrno, target_ulong val)
+{
+#if !defined(CONFIG_USER_ONLY)
+    if (!riscv_has_ext(env, RVJ)) {
+        return -RISCV_EXCP_ILLEGAL_INST;
+    }
+#endif
+    if (check_pm_current_disabled(env, csrno))
+        return 0;
+    env->spmmask = val;
+    env->mstatus |= MSTATUS_XS | MSTATUS_SD;
+    env->mmte |= PM_EXT_DIRTY;
+    return 0;
+}
+
+static int read_upmmask(CPURISCVState *env, int csrno, target_ulong *val)
+{
+#if !defined(CONFIG_USER_ONLY)
+    if (!riscv_has_ext(env, RVJ)) {
+        return -RISCV_EXCP_ILLEGAL_INST;
+    }
+#endif
+    *val = env->upmmask;
+    return 0;
+}
+
+static int write_upmmask(CPURISCVState *env, int csrno, target_ulong val)
+{
+#if !defined(CONFIG_USER_ONLY)
+    if (!riscv_has_ext(env, RVJ)) {
+        return -RISCV_EXCP_ILLEGAL_INST;
+    }
+#endif
+    if (check_pm_current_disabled(env, csrno))
+        return 0;
+    env->upmmask = val;
+    env->mstatus |= MSTATUS_XS | MSTATUS_SD;
+    env->mmte |= PM_EXT_DIRTY;
+    return 0;
+}
+
+static int read_mpmbase(CPURISCVState *env, int csrno, target_ulong *val)
+{
+#if !defined(CONFIG_USER_ONLY)
+    if (!riscv_has_ext(env, RVJ)) {
+        return -RISCV_EXCP_ILLEGAL_INST;
+    }
+#endif
+    *val = env->mpmbase;
+    return 0;
+}
+
+static int write_mpmbase(CPURISCVState *env, int csrno, target_ulong val)
+{
+#if !defined(CONFIG_USER_ONLY)
+    if (!riscv_has_ext(env, RVJ)) {
+        return -RISCV_EXCP_ILLEGAL_INST;
+    }
+#endif
+    env->mpmbase = val;
+    env->mstatus |= MSTATUS_XS | MSTATUS_SD;
+    env->mmte |= PM_EXT_DIRTY;
+    return 0;
+}
+
+static int read_spmbase(CPURISCVState *env, int csrno, target_ulong *val)
+{
+#if !defined(CONFIG_USER_ONLY)
+    if (!riscv_has_ext(env, RVJ)) {
+        return -RISCV_EXCP_ILLEGAL_INST;
+    }
+#endif
+    *val = env->spmbase;
+    return 0;
+}
+
+static int write_spmbase(CPURISCVState *env, int csrno, target_ulong val)
+{
+#if !defined(CONFIG_USER_ONLY)
+    if (!riscv_has_ext(env, RVJ)) {
+        return -RISCV_EXCP_ILLEGAL_INST;
+    }
+#endif
+    if (check_pm_current_disabled(env, csrno))
+        return 0;
+    env->spmbase = val;
+    env->mstatus |= MSTATUS_XS | MSTATUS_SD;
+    env->mmte |= PM_EXT_DIRTY;
+    return 0;
+}
+
+static int read_upmbase(CPURISCVState *env, int csrno, target_ulong *val)
+{
+#if !defined(CONFIG_USER_ONLY)
+    if (!riscv_has_ext(env, RVJ)) {
+        return -RISCV_EXCP_ILLEGAL_INST;
+    }
+#endif
+    *val = env->upmbase;
+    return 0;
+}
+
+static int write_upmbase(CPURISCVState *env, int csrno, target_ulong val)
+{
+#if !defined(CONFIG_USER_ONLY)
+    if (!riscv_has_ext(env, RVJ)) {
+        return -RISCV_EXCP_ILLEGAL_INST;
+    }
+#endif
+    if (check_pm_current_disabled(env, csrno))
+        return 0;
+    env->upmbase = val;
+    env->mstatus |= MSTATUS_XS | MSTATUS_SD;
+    env->mmte |= PM_EXT_DIRTY;
+    return 0;
+}
 #endif
 
 /*
@@ -1471,6 +1733,21 @@ static riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
     [CSR_PMPCFG0  ... CSR_PMPCFG3]   = { pmp,   read_pmpcfg,  write_pmpcfg   },
     [CSR_PMPADDR0 ... CSR_PMPADDR15] = { pmp,   read_pmpaddr, write_pmpaddr  },
 
+    /* User Pointer Masking */
+    [CSR_UMTE] =                { umode,  read_umte,        write_umte        },
+    [CSR_UPMMASK] =             { umode,  read_upmmask,     write_upmmask     },
+    [CSR_UPMBASE] =             { umode,  read_upmbase,     write_upmbase     },
+
+    /* Machine Pointer Masking */
+    [CSR_MMTE] =                { any,  read_mmte,        write_mmte        },
+    [CSR_MPMMASK] =             { any,  read_mpmmask,     write_mpmmask     },
+    [CSR_MPMBASE] =             { any,  read_mpmbase,     write_mpmbase     },
+
+    /* Supervisor Pointer Masking */
+    [CSR_SMTE] =                { smode, read_smte,        write_smte        },
+    [CSR_SPMMASK] =             { smode, read_spmmask,     write_spmmask     },
+    [CSR_SPMBASE] =             { smode, read_spmbase,     write_spmbase     },
+
     /* Performance Counters */
     [CSR_HPMCOUNTER3   ... CSR_HPMCOUNTER31] =    { ctr,  read_zero          },
     [CSR_MHPMCOUNTER3  ... CSR_MHPMCOUNTER31] =   { any,  read_zero          },
-- 
2.20.1