[PATCH v9 2/6] [RISCV_PM] Support CSRs required for RISC-V PM extension except for the h-mode

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

Signed-off-by: Alexey Baturo <space.monkey.delivers@gmail.com>
---
 target/riscv/cpu.c      |   6 +
 target/riscv/cpu.h      |  12 ++
 target/riscv/cpu_bits.h |  97 +++++++++++++
 target/riscv/csr.c      | 306 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 421 insertions(+)

diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index 3191fd0082..9841711e71 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -486,6 +486,12 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp)
         if (cpu->cfg.ext_h) {
             target_misa |= RVH;
         }
+        if (cpu->cfg.ext_j) {
+#ifndef CONFIG_USER_ONLY
+            /* mmte is supposed to have pm.current hardwired to 1 */
+            env->mmte |= (PM_EXT_INITIAL | MMTE_M_PM_CURRENT);
+#endif
+        }
         if (cpu->cfg.ext_v) {
             target_misa |= RVV;
             if (!is_power_of_2(cpu->cfg.vlen)) {
diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index 1673872223..a68e523d87 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -233,6 +233,18 @@ struct CPURISCVState {
 
     /* True if in debugger mode.  */
     bool debugger;
+
+    /*
+     * CSRs for PointerMasking extension
+     * 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 52640e6856..97e2aa8a97 100644
--- a/target/riscv/cpu_bits.h
+++ b/target/riscv/cpu_bits.h
@@ -334,6 +334,39 @@
 #define CSR_MHPMCOUNTER30H  0xb9e
 #define CSR_MHPMCOUNTER31H  0xb9f
 
+
+/*
+ * User PointerMasking registers
+ * NB: actual CSR numbers might be changed in future
+ */
+#define CSR_UMTE            0x4c0
+#define CSR_UPMMASK         0x4c1
+#define CSR_UPMBASE         0x4c2
+
+/*
+ * Machine PointerMasking registers
+ * NB: actual CSR numbers might be changed in future
+ */
+#define CSR_MMTE            0x3c0
+#define CSR_MPMMASK         0x3c1
+#define CSR_MPMBASE         0x3c2
+
+/*
+ * Supervisor PointerMaster registers
+ * NB: actual CSR numbers might be changed in future
+ */
+#define CSR_SMTE            0x1c0
+#define CSR_SPMMASK         0x1c1
+#define CSR_SPMBASE         0x1c2
+
+/*
+ * Hypervisor PointerMaster registers
+ * NB: actual CSR numbers might be changed in future
+ */
+#define CSR_VSMTE           0x2c0
+#define CSR_VSPMMASK        0x2c1
+#define CSR_VSPMBASE        0x2c2
+
 /* mstatus CSR bits */
 #define MSTATUS_UIE         0x00000001
 #define MSTATUS_SIE         0x00000002
@@ -530,4 +563,68 @@ typedef enum RISCVException {
 #define MIE_UTIE                           (1 << IRQ_U_TIMER)
 #define MIE_SSIE                           (1 << IRQ_S_SOFT)
 #define MIE_USIE                           (1 << IRQ_U_SOFT)
+
+/* General PointerMasking CSR bits*/
+#define PM_ENABLE       0x00000001ULL
+#define PM_CURRENT      0x00000002ULL
+#define PM_INSN         0x00000004ULL
+#define PM_XS_MASK      0x00000003ULL
+
+/* PointerMasking 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     5ULL
+#define M_OFFSET     8ULL
+
+#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 U_PM_INSN    (PM_INSN    << U_OFFSET)
+#define S_PM_ENABLE  (PM_ENABLE  << S_OFFSET)
+#define S_PM_CURRENT (PM_CURRENT << S_OFFSET)
+#define S_PM_INSN    (PM_INSN    << S_OFFSET)
+#define M_PM_ENABLE  (PM_ENABLE  << M_OFFSET)
+#define M_PM_CURRENT (PM_CURRENT << M_OFFSET)
+#define M_PM_INSN    (PM_INSN    << 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_U_PM_INSN      U_PM_INSN
+#define MMTE_S_PM_ENABLE    S_PM_ENABLE
+#define MMTE_S_PM_CURRENT   S_PM_CURRENT
+#define MMTE_S_PM_INSN      S_PM_INSN
+#define MMTE_M_PM_ENABLE    M_PM_ENABLE
+#define MMTE_M_PM_CURRENT   M_PM_CURRENT
+#define MMTE_M_PM_INSN      M_PM_INSN
+#define MMTE_MASK    (MMTE_U_PM_ENABLE | MMTE_U_PM_CURRENT | MMTE_U_PM_INSN | \
+                      MMTE_S_PM_ENABLE | MMTE_S_PM_CURRENT | MMTE_S_PM_INSN | \
+                      MMTE_M_PM_ENABLE | MMTE_M_PM_CURRENT | MMTE_M_PM_INSN | \
+                      MMTE_PM_XS_BITS)
+
+/* (v)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_U_PM_INSN      U_PM_INSN
+#define SMTE_S_PM_ENABLE    S_PM_ENABLE
+#define SMTE_S_PM_CURRENT   S_PM_CURRENT
+#define SMTE_S_PM_INSN      S_PM_INSN
+#define SMTE_MASK    (SMTE_U_PM_ENABLE | SMTE_U_PM_CURRENT | SMTE_U_PM_INSN | \
+                      SMTE_S_PM_ENABLE | SMTE_S_PM_CURRENT | SMTE_S_PM_INSN | \
+                      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_U_PM_INSN      U_PM_INSN
+#define UMTE_MASK     (UMTE_U_PM_ENABLE | MMTE_U_PM_CURRENT | UMTE_U_PM_INSN)
+
 #endif
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index fe5628fea6..e1c5bb9c35 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -192,6 +192,16 @@ static RISCVException hmode32(CPURISCVState *env, int csrno)
 
 }
 
+/* Checks if PointerMasking registers could be accessed */
+static RISCVException pointer_masking(CPURISCVState *env, int csrno)
+{
+    /* Check if j-ext is present */
+    if (riscv_has_ext(env, RVJ)) {
+        return RISCV_EXCP_NONE;
+    }
+    return RISCV_EXCP_ILLEGAL_INST;
+}
+
 static RISCVException pmp(CPURISCVState *env, int csrno)
 {
     if (riscv_feature(env, RISCV_FEATURE_PMP)) {
@@ -1420,6 +1430,289 @@ static RISCVException write_pmpaddr(CPURISCVState *env, int csrno,
     return RISCV_EXCP_NONE;
 }
 
+/*
+ * 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)
+{
+    int csr_priv = get_field(csrno, 0x300);
+    /*
+     * If priv lvls differ that means we're accessing csr from higher priv lvl,
+     * so allow the access
+     */
+    if (env->priv != csr_priv) {
+        return 0;
+    }
+    int cur_bit_pos;
+    switch (env->priv) {
+    case PRV_M:
+        cur_bit_pos = M_PM_CURRENT;
+        break;
+    case PRV_S:
+        cur_bit_pos = S_PM_CURRENT;
+        break;
+    case PRV_U:
+        cur_bit_pos = U_PM_CURRENT;
+        break;
+    default:
+        g_assert_not_reached();
+    }
+    int pm_current = get_field(env->mmte, cur_bit_pos);
+    /* It's same priv lvl, so we allow to modify csr only if pm.current==1 */
+    return !pm_current;
+}
+
+static RISCVException read_mmte(CPURISCVState *env, int csrno,
+                                target_ulong *val)
+{
+    *val = env->mmte & MMTE_MASK;
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException write_mmte(CPURISCVState *env, int csrno,
+                                 target_ulong val)
+{
+    uint64_t mstatus;
+    target_ulong wpri_val = val & MMTE_MASK;
+    if (val != wpri_val) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "MMTE: WPRI violation written 0x%lx vs expected 0x%lx\n",
+                      val, wpri_val);
+    }
+    /* for machine mode pm.current is hardwired to 1 */
+    wpri_val |= MMTE_M_PM_CURRENT;
+    /* hardwiring pm.instruction bit to 0, since it's not supported yet */
+    wpri_val &= ~(MMTE_M_PM_INSN | MMTE_S_PM_INSN | MMTE_U_PM_INSN);
+    env->mmte = wpri_val | PM_EXT_DIRTY;
+    /* Set XS and SD bits, since PM CSRs are dirty */
+    mstatus = env->mstatus;
+    if (riscv_cpu_is_32bit(env)) {
+        mstatus = set_field(mstatus, MSTATUS32_SD, 1);
+    } else {
+        mstatus = set_field(mstatus, MSTATUS64_SD, 1);
+    }
+    env->mstatus |= MSTATUS_XS;
+    env->mstatus = mstatus;
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException read_smte(CPURISCVState *env, int csrno,
+                                target_ulong *val)
+{
+    *val = env->mmte & SMTE_MASK;
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException write_smte(CPURISCVState *env, int csrno,
+                                 target_ulong val)
+{
+    target_ulong wpri_val = val & SMTE_MASK;
+    if (val != wpri_val) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "SMTE: WPRI violation written 0x%lx vs expected 0x%lx\n",
+                      val, wpri_val);
+    }
+    /* if pm.current==0 we can't modify current PM CSRs */
+    if (check_pm_current_disabled(env, csrno)) {
+        return RISCV_EXCP_NONE;
+    }
+    target_ulong new_val = wpri_val | (env->mmte & ~SMTE_MASK);
+    write_mmte(env, csrno, new_val);
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException read_umte(CPURISCVState *env, int csrno,
+                                target_ulong *val)
+{
+    *val = env->mmte & UMTE_MASK;
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException write_umte(CPURISCVState *env, int csrno,
+                                 target_ulong val)
+{
+    target_ulong wpri_val = val & UMTE_MASK;
+    if (val != wpri_val) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "UMTE: WPRI violation written 0x%lx vs expected 0x%lx\n",
+                      val, wpri_val);
+    }
+    if (check_pm_current_disabled(env, csrno)) {
+        return RISCV_EXCP_NONE;
+    }
+    target_ulong new_val = wpri_val | (env->mmte & ~UMTE_MASK);
+    write_mmte(env, csrno, new_val);
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException read_mpmmask(CPURISCVState *env, int csrno,
+                                   target_ulong *val)
+{
+    *val = env->mpmmask;
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException write_mpmmask(CPURISCVState *env, int csrno,
+                                    target_ulong val)
+{
+    uint64_t mstatus;
+    env->mpmmask = val;
+    env->mmte |= PM_EXT_DIRTY;
+    /* Set XS and SD bits, since PM CSRs are dirty */
+    mstatus = env->mstatus;
+    if (riscv_cpu_is_32bit(env)) {
+        mstatus = set_field(mstatus, MSTATUS32_SD, 1);
+    } else {
+        mstatus = set_field(mstatus, MSTATUS64_SD, 1);
+    }
+    env->mstatus |= MSTATUS_XS;
+    env->mstatus = mstatus;
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException read_spmmask(CPURISCVState *env, int csrno,
+                                   target_ulong *val)
+{
+    *val = env->spmmask;
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException write_spmmask(CPURISCVState *env, int csrno,
+                                    target_ulong val)
+{
+    uint64_t mstatus;
+    /* if pm.current==0 we can't modify current PM CSRs */
+    if (check_pm_current_disabled(env, csrno)) {
+        return RISCV_EXCP_NONE;
+    }
+    env->spmmask = val;
+    env->mmte |= PM_EXT_DIRTY;
+    /* Set XS and SD bits, since PM CSRs are dirty */
+    mstatus = env->mstatus;
+    if (riscv_cpu_is_32bit(env)) {
+        mstatus = set_field(mstatus, MSTATUS32_SD, 1);
+    } else {
+        mstatus = set_field(mstatus, MSTATUS64_SD, 1);
+    }
+    env->mstatus |= MSTATUS_XS;
+    env->mstatus = mstatus;
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException read_upmmask(CPURISCVState *env, int csrno,
+                                   target_ulong *val)
+{
+    *val = env->upmmask;
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException write_upmmask(CPURISCVState *env, int csrno,
+                                    target_ulong val)
+{
+    uint64_t mstatus;
+    /* if pm.current==0 we can't modify current PM CSRs */
+    if (check_pm_current_disabled(env, csrno)) {
+        return RISCV_EXCP_NONE;
+    }
+    env->upmmask = val;
+    env->mmte |= PM_EXT_DIRTY;
+    /* Set XS and SD bits, since PM CSRs are dirty */
+    mstatus = env->mstatus;
+    if (riscv_cpu_is_32bit(env)) {
+        mstatus = set_field(mstatus, MSTATUS32_SD, 1);
+    } else {
+        mstatus = set_field(mstatus, MSTATUS64_SD, 1);
+    }
+    env->mstatus |= MSTATUS_XS;
+    env->mstatus = mstatus;
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException read_mpmbase(CPURISCVState *env, int csrno,
+                                   target_ulong *val)
+{
+    *val = env->mpmbase;
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException write_mpmbase(CPURISCVState *env, int csrno,
+                                    target_ulong val)
+{
+    uint64_t mstatus;
+    env->mpmbase = val;
+    env->mmte |= PM_EXT_DIRTY;
+    /* Set XS and SD bits, since PM CSRs are dirty */
+    mstatus = env->mstatus;
+    if (riscv_cpu_is_32bit(env)) {
+        mstatus = set_field(mstatus, MSTATUS32_SD, 1);
+    } else {
+        mstatus = set_field(mstatus, MSTATUS64_SD, 1);
+    }
+    env->mstatus |= MSTATUS_XS;
+    env->mstatus = mstatus;
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException read_spmbase(CPURISCVState *env, int csrno,
+                                   target_ulong *val)
+{
+    *val = env->spmbase;
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException write_spmbase(CPURISCVState *env, int csrno,
+                                    target_ulong val)
+{
+    uint64_t mstatus;
+    /* if pm.current==0 we can't modify current PM CSRs */
+    if (check_pm_current_disabled(env, csrno)) {
+        return RISCV_EXCP_NONE;
+    }
+    env->spmbase = val;
+    env->mmte |= PM_EXT_DIRTY;
+    /* Set XS and SD bits, since PM CSRs are dirty */
+    mstatus = env->mstatus;
+    if (riscv_cpu_is_32bit(env)) {
+        mstatus = set_field(mstatus, MSTATUS32_SD, 1);
+    } else {
+        mstatus = set_field(mstatus, MSTATUS64_SD, 1);
+    }
+    env->mstatus |= MSTATUS_XS;
+    env->mstatus = mstatus;
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException read_upmbase(CPURISCVState *env, int csrno,
+                                   target_ulong *val)
+{
+    *val = env->upmbase;
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException write_upmbase(CPURISCVState *env, int csrno,
+                                    target_ulong val)
+{
+    uint64_t mstatus;
+    /* if pm.current==0 we can't modify current PM CSRs */
+    if (check_pm_current_disabled(env, csrno)) {
+        return RISCV_EXCP_NONE;
+    }
+    env->upmbase = val;
+    env->mmte |= PM_EXT_DIRTY;
+    /* Set XS and SD bits, since PM CSRs are dirty */
+    mstatus = env->mstatus;
+    if (riscv_cpu_is_32bit(env)) {
+        mstatus = set_field(mstatus, MSTATUS32_SD, 1);
+    } else {
+        mstatus = set_field(mstatus, MSTATUS64_SD, 1);
+    }
+    env->mstatus |= MSTATUS_XS;
+    env->mstatus = mstatus;
+    return RISCV_EXCP_NONE;
+}
+
 #endif
 
 /*
@@ -1652,6 +1945,19 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
     [CSR_PMPADDR14] =  { "pmpaddr14", pmp, read_pmpaddr, write_pmpaddr },
     [CSR_PMPADDR15] =  { "pmpaddr15", pmp, read_pmpaddr, write_pmpaddr },
 
+    /* User Pointer Masking */
+    [CSR_UMTE]    =    { "umte",    pointer_masking, read_umte,    write_umte    },
+    [CSR_UPMMASK] =    { "upmmask", pointer_masking, read_upmmask, write_upmmask },
+    [CSR_UPMBASE] =    { "upmbase", pointer_masking, read_upmbase, write_upmbase },
+    /* Machine Pointer Masking */
+    [CSR_MMTE]    =    { "mmte",    pointer_masking, read_mmte,    write_mmte    },
+    [CSR_MPMMASK] =    { "mpmmask", pointer_masking, read_mpmmask, write_mpmmask },
+    [CSR_MPMBASE] =    { "mpmbase", pointer_masking, read_mpmbase, write_mpmbase },
+    /* Supervisor Pointer Masking */
+    [CSR_SMTE]    =    { "smte",    pointer_masking, read_smte,    write_smte    },
+    [CSR_SPMMASK] =    { "spmmask", pointer_masking, read_spmmask, write_spmmask },
+    [CSR_SPMBASE] =    { "spmbase", pointer_masking, read_spmbase, write_spmbase },
+
     /* Performance Counters */
     [CSR_HPMCOUNTER3]    = { "hpmcounter3",    ctr,    read_zero },
     [CSR_HPMCOUNTER4]    = { "hpmcounter4",    ctr,    read_zero },
-- 
2.20.1