target/riscv/csr.c

   1 /*
   2  * RISC-V Control and Status Registers.
   3  *
   4  * Copyright (c) 2016-2017 Sagar Karandikar, sagark@eecs.berkeley.edu
   5  * Copyright (c) 2017-2018 SiFive, Inc.
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms and conditions of the GNU General Public License,
   9  * version 2 or later, as published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14  * more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along with
  17  * this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include "qemu/osdep.h"
  21 #include "qemu/log.h"
  22 #include "cpu.h"
  23 #include "qemu/main-loop.h"
  24 #include "exec/exec-all.h"
  25
  26 /* CSR function table */
  27 static riscv_csr_operations csr_ops[];
  28
  29 /* CSR function table constants */
  30 enum {
  31     CSR_TABLE_SIZE = 0x1000
  32 };
  33
  34 /* CSR function table public API */
  35 void riscv_get_csr_ops(int csrno, riscv_csr_operations *ops)
  36 {
  37     *ops = csr_ops[csrno & (CSR_TABLE_SIZE - 1)];
  38 }
  39
  40 void riscv_set_csr_ops(int csrno, riscv_csr_operations *ops)
  41 {
  42     csr_ops[csrno & (CSR_TABLE_SIZE - 1)] = *ops;
  43 }
  44
  45 /* Predicates */
  46 static int fs(CPURISCVState *env, int csrno)
  47 {
  48 #if !defined(CONFIG_USER_ONLY)
  49     if (!(env->mstatus & MSTATUS_FS)) {
  50         return -1;
  51     }
  52 #endif
  53     return 0;
  54 }
  55
  56 static int ctr(CPURISCVState *env, int csrno)
  57 {
  58 #if !defined(CONFIG_USER_ONLY)
  59     uint32_t ctr_en = ~0u;
  60
  61     if (env->priv < PRV_M) {
  62         ctr_en &= env->mcounteren;
  63     }
  64     if (env->priv < PRV_S) {
  65         ctr_en &= env->scounteren;
  66     }
  67     if (!(ctr_en & (1u << (csrno & 31)))) {
  68         return -1;
  69     }
  70 #endif
  71     return 0;
  72 }
  73
  74 #if !defined(CONFIG_USER_ONLY)
  75 static int any(CPURISCVState *env, int csrno)
  76 {
  77     return 0;
  78 }
  79
  80 static int smode(CPURISCVState *env, int csrno)
  81 {
  82     return -!riscv_has_ext(env, RVS);
  83 }
  84
  85 static int pmp(CPURISCVState *env, int csrno)
  86 {
  87     return -!riscv_feature(env, RISCV_FEATURE_PMP);
  88 }
  89 #endif
  90
  91 /* User Floating-Point CSRs */
  92 static int read_fflags(CPURISCVState *env, int csrno, target_ulong *val)
  93 {
  94 #if !defined(CONFIG_USER_ONLY)
  95     if (!(env->mstatus & MSTATUS_FS)) {
  96         return -1;
  97     }
  98 #endif
  99     *val = riscv_cpu_get_fflags(env);
 100     return 0;
 101 }
 102
 103 static int write_fflags(CPURISCVState *env, int csrno, target_ulong val)
 104 {
 105 #if !defined(CONFIG_USER_ONLY)
 106     if (!(env->mstatus & MSTATUS_FS)) {
 107         return -1;
 108     }
 109     env->mstatus |= MSTATUS_FS;
 110 #endif
 111     riscv_cpu_set_fflags(env, val & (FSR_AEXC >> FSR_AEXC_SHIFT));
 112     return 0;
 113 }
 114
 115 static int read_frm(CPURISCVState *env, int csrno, target_ulong *val)
 116 {
 117 #if !defined(CONFIG_USER_ONLY)
 118     if (!(env->mstatus & MSTATUS_FS)) {
 119         return -1;
 120     }
 121 #endif
 122     *val = env->frm;
 123     return 0;
 124 }
 125
 126 static int write_frm(CPURISCVState *env, int csrno, target_ulong val)
 127 {
 128 #if !defined(CONFIG_USER_ONLY)
 129     if (!(env->mstatus & MSTATUS_FS)) {
 130         return -1;
 131     }
 132     env->mstatus |= MSTATUS_FS;
 133 #endif
 134     env->frm = val & (FSR_RD >> FSR_RD_SHIFT);
 135     return 0;
 136 }
 137
 138 static int read_fcsr(CPURISCVState *env, int csrno, target_ulong *val)
 139 {
 140 #if !defined(CONFIG_USER_ONLY)
 141     if (!(env->mstatus & MSTATUS_FS)) {
 142         return -1;
 143     }
 144 #endif
 145     *val = (riscv_cpu_get_fflags(env) << FSR_AEXC_SHIFT)
 146         | (env->frm << FSR_RD_SHIFT);
 147     return 0;
 148 }
 149
 150 static int write_fcsr(CPURISCVState *env, int csrno, target_ulong val)
 151 {
 152 #if !defined(CONFIG_USER_ONLY)
 153     if (!(env->mstatus & MSTATUS_FS)) {
 154         return -1;
 155     }
 156     env->mstatus |= MSTATUS_FS;
 157 #endif
 158     env->frm = (val & FSR_RD) >> FSR_RD_SHIFT;
 159     riscv_cpu_set_fflags(env, (val & FSR_AEXC) >> FSR_AEXC_SHIFT);
 160     return 0;
 161 }
 162
 163 /* User Timers and Counters */
 164 static int read_instret(CPURISCVState *env, int csrno, target_ulong *val)
 165 {
 166 #if !defined(CONFIG_USER_ONLY)
 167     if (use_icount) {
 168         *val = cpu_get_icount();
 169     } else {
 170         *val = cpu_get_host_ticks();
 171     }
 172 #else
 173     *val = cpu_get_host_ticks();
 174 #endif
 175     return 0;
 176 }
 177
 178 #if defined(TARGET_RISCV32)
 179 static int read_instreth(CPURISCVState *env, int csrno, target_ulong *val)
 180 {
 181 #if !defined(CONFIG_USER_ONLY)
 182     if (use_icount) {
 183         *val = cpu_get_icount() >> 32;
 184     } else {
 185         *val = cpu_get_host_ticks() >> 32;
 186     }
 187 #else
 188     *val = cpu_get_host_ticks() >> 32;
 189 #endif
 190     return 0;
 191 }
 192 #endif /* TARGET_RISCV32 */
 193
 194 #if defined(CONFIG_USER_ONLY)
 195 static int read_time(CPURISCVState *env, int csrno, target_ulong *val)
 196 {
 197     *val = cpu_get_host_ticks();
 198     return 0;
 199 }
 200
 201 #if defined(TARGET_RISCV32)
 202 static int read_timeh(CPURISCVState *env, int csrno, target_ulong *val)
 203 {
 204     *val = cpu_get_host_ticks() >> 32;
 205     return 0;
 206 }
 207 #endif
 208
 209 #else /* CONFIG_USER_ONLY */
 210
 211 /* Machine constants */
 212
 213 #define M_MODE_INTERRUPTS (MIP_MSIP | MIP_MTIP | MIP_MEIP)
 214 #define S_MODE_INTERRUPTS (MIP_SSIP | MIP_STIP | MIP_SEIP)
 215
 216 static const target_ulong delegable_ints = S_MODE_INTERRUPTS;
 217 static const target_ulong all_ints = M_MODE_INTERRUPTS | S_MODE_INTERRUPTS;
 218 static const target_ulong delegable_excps =
 219     (1ULL << (RISCV_EXCP_INST_ADDR_MIS)) |
 220     (1ULL << (RISCV_EXCP_INST_ACCESS_FAULT)) |
 221     (1ULL << (RISCV_EXCP_ILLEGAL_INST)) |
 222     (1ULL << (RISCV_EXCP_BREAKPOINT)) |
 223     (1ULL << (RISCV_EXCP_LOAD_ADDR_MIS)) |
 224     (1ULL << (RISCV_EXCP_LOAD_ACCESS_FAULT)) |
 225     (1ULL << (RISCV_EXCP_STORE_AMO_ADDR_MIS)) |
 226     (1ULL << (RISCV_EXCP_STORE_AMO_ACCESS_FAULT)) |
 227     (1ULL << (RISCV_EXCP_U_ECALL)) |
 228     (1ULL << (RISCV_EXCP_S_ECALL)) |
 229     (1ULL << (RISCV_EXCP_H_ECALL)) |
 230     (1ULL << (RISCV_EXCP_M_ECALL)) |
 231     (1ULL << (RISCV_EXCP_INST_PAGE_FAULT)) |
 232     (1ULL << (RISCV_EXCP_LOAD_PAGE_FAULT)) |
 233     (1ULL << (RISCV_EXCP_STORE_PAGE_FAULT));
 234 static const target_ulong sstatus_v1_9_mask = SSTATUS_SIE | SSTATUS_SPIE |
 235     SSTATUS_UIE | SSTATUS_UPIE | SSTATUS_SPP | SSTATUS_FS | SSTATUS_XS |
 236     SSTATUS_SUM | SSTATUS_SD;
 237 static const target_ulong sstatus_v1_10_mask = SSTATUS_SIE | SSTATUS_SPIE |
 238     SSTATUS_UIE | SSTATUS_UPIE | SSTATUS_SPP | SSTATUS_FS | SSTATUS_XS |
 239     SSTATUS_SUM | SSTATUS_MXR | SSTATUS_SD;
 240
 241 #if defined(TARGET_RISCV32)
 242 static const char valid_vm_1_09[16] = {
 243     [VM_1_09_MBARE] = 1,
 244     [VM_1_09_SV32] = 1,
 245 };
 246 static const char valid_vm_1_10[16] = {
 247     [VM_1_10_MBARE] = 1,
 248     [VM_1_10_SV32] = 1
 249 };
 250 #elif defined(TARGET_RISCV64)
 251 static const char valid_vm_1_09[16] = {
 252     [VM_1_09_MBARE] = 1,
 253     [VM_1_09_SV39] = 1,
 254     [VM_1_09_SV48] = 1,
 255 };
 256 static const char valid_vm_1_10[16] = {
 257     [VM_1_10_MBARE] = 1,
 258     [VM_1_10_SV39] = 1,
 259     [VM_1_10_SV48] = 1,
 260     [VM_1_10_SV57] = 1
 261 };
 262 #endif /* CONFIG_USER_ONLY */
 263
 264 /* Machine Information Registers */
 265 static int read_zero(CPURISCVState *env, int csrno, target_ulong *val)
 266 {
 267     return *val = 0;
 268 }
 269
 270 static int read_mhartid(CPURISCVState *env, int csrno, target_ulong *val)
 271 {
 272     *val = env->mhartid;
 273     return 0;
 274 }
 275
 276 /* Machine Trap Setup */
 277 static int read_mstatus(CPURISCVState *env, int csrno, target_ulong *val)
 278 {
 279     *val = env->mstatus;
 280     return 0;
 281 }
 282
 283 static int validate_vm(CPURISCVState *env, target_ulong vm)
 284 {
 285     return (env->priv_ver >= PRIV_VERSION_1_10_0) ?
 286         valid_vm_1_10[vm & 0xf] : valid_vm_1_09[vm & 0xf];
 287 }
 288
 289 static int write_mstatus(CPURISCVState *env, int csrno, target_ulong val)
 290 {
 291     target_ulong mstatus = env->mstatus;
 292     target_ulong mask = 0;
 293     target_ulong mpp = get_field(val, MSTATUS_MPP);
 294
 295     /* flush tlb on mstatus fields that affect VM */
 296     if (env->priv_ver <= PRIV_VERSION_1_09_1) {
 297         if ((val ^ mstatus) & (MSTATUS_MXR | MSTATUS_MPP |
 298                 MSTATUS_MPRV | MSTATUS_SUM | MSTATUS_VM)) {
 299             tlb_flush(CPU(riscv_env_get_cpu(env)));
 300         }
 301         mask = MSTATUS_SIE | MSTATUS_SPIE | MSTATUS_MIE | MSTATUS_MPIE |
 302             MSTATUS_SPP | MSTATUS_FS | MSTATUS_MPRV | MSTATUS_SUM |
 303             MSTATUS_MPP | MSTATUS_MXR |
 304             (validate_vm(env, get_field(val, MSTATUS_VM)) ?
 305                 MSTATUS_VM : 0);
 306     }
 307     if (env->priv_ver >= PRIV_VERSION_1_10_0) {
 308         if ((val ^ mstatus) & (MSTATUS_MXR | MSTATUS_MPP |
 309                 MSTATUS_MPRV | MSTATUS_SUM)) {
 310             tlb_flush(CPU(riscv_env_get_cpu(env)));
 311         }
 312         mask = MSTATUS_SIE | MSTATUS_SPIE | MSTATUS_MIE | MSTATUS_MPIE |
 313             MSTATUS_SPP | MSTATUS_FS | MSTATUS_MPRV | MSTATUS_SUM |
 314             MSTATUS_MPP | MSTATUS_MXR | MSTATUS_TVM | MSTATUS_TSR |
 315             MSTATUS_TW;
 316     }
 317
 318     /* silenty discard mstatus.mpp writes for unsupported modes */
 319     if (mpp == PRV_H ||
 320         (!riscv_has_ext(env, RVS) && mpp == PRV_S) ||
 321         (!riscv_has_ext(env, RVU) && mpp == PRV_U)) {
 322         mask &= ~MSTATUS_MPP;
 323     }
 324
 325     mstatus = (mstatus & ~mask) | (val & mask);
 326
 327     int dirty = ((mstatus & MSTATUS_FS) == MSTATUS_FS) |
 328                 ((mstatus & MSTATUS_XS) == MSTATUS_XS);
 329     mstatus = set_field(mstatus, MSTATUS_SD, dirty);
 330     env->mstatus = mstatus;
 331
 332     return 0;
 333 }
 334
 335 static int read_misa(CPURISCVState *env, int csrno, target_ulong *val)
 336 {
 337     *val = env->misa;
 338     return 0;
 339 }
 340
 341 static int write_misa(CPURISCVState *env, int csrno, target_ulong val)
 342 {
 343     if (!riscv_feature(env, RISCV_FEATURE_MISA)) {
 344         /* drop write to misa */
 345         return 0;
 346     }
 347
 348     /* 'I' or 'E' must be present */
 349     if (!(val & (RVI | RVE))) {
 350         /* It is not, drop write to misa */
 351         return 0;
 352     }
 353
 354     /* 'E' excludes all other extensions */
 355     if (val & RVE) {
 356         /* when we support 'E' we can do "val = RVE;" however
 357          * for now we just drop writes if 'E' is present.
 358          */
 359         return 0;
 360     }
 361
 362     /* Mask extensions that are not supported by this hart */
 363     val &= env->misa_mask;
 364
 365     /* Mask extensions that are not supported by QEMU */
 366     val &= (RVI | RVE | RVM | RVA | RVF | RVD | RVC | RVS | RVU);
 367
 368     /* 'D' depends on 'F', so clear 'D' if 'F' is not present */
 369     if ((val & RVD) && !(val & RVF)) {
 370         val &= ~RVD;
 371     }
 372
 373     /* Suppress 'C' if next instruction is not aligned
 374      * TODO: this should check next_pc
 375      */
 376     if ((val & RVC) && (GETPC() & ~3) != 0) {
 377         val &= ~RVC;
 378     }
 379
 380     /* misa.MXL writes are not supported by QEMU */
 381     val = (env->misa & MISA_MXL) | (val & ~MISA_MXL);
 382
 383     /* flush translation cache */
 384     if (val != env->misa) {
 385         tb_flush(CPU(riscv_env_get_cpu(env)));
 386     }
 387
 388     env->misa = val;
 389
 390     return 0;
 391 }
 392
 393 static int read_medeleg(CPURISCVState *env, int csrno, target_ulong *val)
 394 {
 395     *val = env->medeleg;
 396     return 0;
 397 }
 398
 399 static int write_medeleg(CPURISCVState *env, int csrno, target_ulong val)
 400 {
 401     env->medeleg = (env->medeleg & ~delegable_excps) | (val & delegable_excps);
 402     return 0;
 403 }
 404
 405 static int read_mideleg(CPURISCVState *env, int csrno, target_ulong *val)
 406 {
 407     *val = env->mideleg;
 408     return 0;
 409 }
 410
 411 static int write_mideleg(CPURISCVState *env, int csrno, target_ulong val)
 412 {
 413     env->mideleg = (env->mideleg & ~delegable_ints) | (val & delegable_ints);
 414     return 0;
 415 }
 416
 417 static int read_mie(CPURISCVState *env, int csrno, target_ulong *val)
 418 {
 419     *val = env->mie;
 420     return 0;
 421 }
 422
 423 static int write_mie(CPURISCVState *env, int csrno, target_ulong val)
 424 {
 425     env->mie = (env->mie & ~all_ints) | (val & all_ints);
 426     return 0;
 427 }
 428
 429 static int read_mtvec(CPURISCVState *env, int csrno, target_ulong *val)
 430 {
 431     *val = env->mtvec;
 432     return 0;
 433 }
 434
 435 static int write_mtvec(CPURISCVState *env, int csrno, target_ulong val)
 436 {
 437     /* bits [1:0] encode mode; 0 = direct, 1 = vectored, 2 >= reserved */
 438     if ((val & 3) == 0) {
 439         env->mtvec = val >> 2 << 2;
 440     } else {
 441         qemu_log_mask(LOG_UNIMP, "CSR_MTVEC: vectored traps not supported");
 442     }
 443     return 0;
 444 }
 445
 446 static int read_mcounteren(CPURISCVState *env, int csrno, target_ulong *val)
 447 {
 448     if (env->priv_ver < PRIV_VERSION_1_10_0) {
 449         return -1;
 450     }
 451     *val = env->mcounteren;
 452     return 0;
 453 }
 454
 455 static int write_mcounteren(CPURISCVState *env, int csrno, target_ulong val)
 456 {
 457     if (env->priv_ver < PRIV_VERSION_1_10_0) {
 458         return -1;
 459     }
 460     env->mcounteren = val;
 461     return 0;
 462 }
 463
 464 static int read_mscounteren(CPURISCVState *env, int csrno, target_ulong *val)
 465 {
 466     if (env->priv_ver > PRIV_VERSION_1_09_1) {
 467         return -1;
 468     }
 469     *val = env->mcounteren;
 470     return 0;
 471 }
 472
 473 static int write_mscounteren(CPURISCVState *env, int csrno, target_ulong val)
 474 {
 475     if (env->priv_ver > PRIV_VERSION_1_09_1) {
 476         return -1;
 477     }
 478     env->mcounteren = val;
 479     return 0;
 480 }
 481
 482 static int read_mucounteren(CPURISCVState *env, int csrno, target_ulong *val)
 483 {
 484     if (env->priv_ver > PRIV_VERSION_1_09_1) {
 485         return -1;
 486     }
 487     *val = env->scounteren;
 488     return 0;
 489 }
 490
 491 static int write_mucounteren(CPURISCVState *env, int csrno, target_ulong val)
 492 {
 493     if (env->priv_ver > PRIV_VERSION_1_09_1) {
 494         return -1;
 495     }
 496     env->scounteren = val;
 497     return 0;
 498 }
 499
 500 /* Machine Trap Handling */
 501 static int read_mscratch(CPURISCVState *env, int csrno, target_ulong *val)
 502 {
 503     *val = env->mscratch;
 504     return 0;
 505 }
 506
 507 static int write_mscratch(CPURISCVState *env, int csrno, target_ulong val)
 508 {
 509     env->mscratch = val;
 510     return 0;
 511 }
 512
 513 static int read_mepc(CPURISCVState *env, int csrno, target_ulong *val)
 514 {
 515     *val = env->mepc;
 516     return 0;
 517 }
 518
 519 static int write_mepc(CPURISCVState *env, int csrno, target_ulong val)
 520 {
 521     env->mepc = val;
 522     return 0;
 523 }
 524
 525 static int read_mcause(CPURISCVState *env, int csrno, target_ulong *val)
 526 {
 527     *val = env->mcause;
 528     return 0;
 529 }
 530
 531 static int write_mcause(CPURISCVState *env, int csrno, target_ulong val)
 532 {
 533     env->mcause = val;
 534     return 0;
 535 }
 536
 537 static int read_mbadaddr(CPURISCVState *env, int csrno, target_ulong *val)
 538 {
 539     *val = env->mbadaddr;
 540     return 0;
 541 }
 542
 543 static int write_mbadaddr(CPURISCVState *env, int csrno, target_ulong val)
 544 {
 545     env->mbadaddr = val;
 546     return 0;
 547 }
 548
 549 static int rmw_mip(CPURISCVState *env, int csrno, target_ulong *ret_value,
 550                    target_ulong new_value, target_ulong write_mask)
 551 {
 552     RISCVCPU *cpu = riscv_env_get_cpu(env);
 553     target_ulong mask = write_mask & delegable_ints;
 554     uint32_t old_mip;
 555
 556     /* We can't allow the supervisor to control SEIP as this would allow the
 557      * supervisor to clear a pending external interrupt which will result in
 558      * lost a interrupt in the case a PLIC is attached. The SEIP bit must be
 559      * hardware controlled when a PLIC is attached. This should be an option
 560      * for CPUs with software-delegated Supervisor External Interrupts. */
 561     mask &= ~MIP_SEIP;
 562
 563     if (mask) {
 564         qemu_mutex_lock_iothread();
 565         old_mip = riscv_cpu_update_mip(cpu, mask, (new_value & mask));
 566         qemu_mutex_unlock_iothread();
 567     } else {
 568         old_mip = atomic_read(&env->mip);
 569     }
 570
 571     if (ret_value) {
 572         *ret_value = old_mip;
 573     }
 574
 575     return 0;
 576 }
 577
 578 /* Supervisor Trap Setup */
 579 static int read_sstatus(CPURISCVState *env, int csrno, target_ulong *val)
 580 {
 581     target_ulong mask = ((env->priv_ver >= PRIV_VERSION_1_10_0) ?
 582                          sstatus_v1_10_mask : sstatus_v1_9_mask);
 583     *val = env->mstatus & mask;
 584     return 0;
 585 }
 586
 587 static int write_sstatus(CPURISCVState *env, int csrno, target_ulong val)
 588 {
 589     target_ulong mask = ((env->priv_ver >= PRIV_VERSION_1_10_0) ?
 590                          sstatus_v1_10_mask : sstatus_v1_9_mask);
 591     target_ulong newval = (env->mstatus & ~mask) | (val & mask);
 592     return write_mstatus(env, CSR_MSTATUS, newval);
 593 }
 594
 595 static int read_sie(CPURISCVState *env, int csrno, target_ulong *val)
 596 {
 597     *val = env->mie & env->mideleg;
 598     return 0;
 599 }
 600
 601 static int write_sie(CPURISCVState *env, int csrno, target_ulong val)
 602 {
 603     target_ulong newval = (env->mie & ~env->mideleg) | (val & env->mideleg);
 604     return write_mie(env, CSR_MIE, newval);
 605 }
 606
 607 static int read_stvec(CPURISCVState *env, int csrno, target_ulong *val)
 608 {
 609     *val = env->stvec;
 610     return 0;
 611 }
 612
 613 static int write_stvec(CPURISCVState *env, int csrno, target_ulong val)
 614 {
 615     /* bits [1:0] encode mode; 0 = direct, 1 = vectored, 2 >= reserved */
 616     if ((val & 3) == 0) {
 617         env->stvec = val >> 2 << 2;
 618     } else {
 619         qemu_log_mask(LOG_UNIMP, "CSR_STVEC: vectored traps not supported");
 620     }
 621     return 0;
 622 }
 623
 624 static int read_scounteren(CPURISCVState *env, int csrno, target_ulong *val)
 625 {
 626     if (env->priv_ver < PRIV_VERSION_1_10_0) {
 627         return -1;
 628     }
 629     *val = env->scounteren;
 630     return 0;
 631 }
 632
 633 static int write_scounteren(CPURISCVState *env, int csrno, target_ulong val)
 634 {
 635     if (env->priv_ver < PRIV_VERSION_1_10_0) {
 636         return -1;
 637     }
 638     env->scounteren = val;
 639     return 0;
 640 }
 641
 642 /* Supervisor Trap Handling */
 643 static int read_sscratch(CPURISCVState *env, int csrno, target_ulong *val)
 644 {
 645     *val = env->sscratch;
 646     return 0;
 647 }
 648
 649 static int write_sscratch(CPURISCVState *env, int csrno, target_ulong val)
 650 {
 651     env->sscratch = val;
 652     return 0;
 653 }
 654
 655 static int read_sepc(CPURISCVState *env, int csrno, target_ulong *val)
 656 {
 657     *val = env->sepc;
 658     return 0;
 659 }
 660
 661 static int write_sepc(CPURISCVState *env, int csrno, target_ulong val)
 662 {
 663     env->sepc = val;
 664     return 0;
 665 }
 666
 667 static int read_scause(CPURISCVState *env, int csrno, target_ulong *val)
 668 {
 669     *val = env->scause;
 670     return 0;
 671 }
 672
 673 static int write_scause(CPURISCVState *env, int csrno, target_ulong val)
 674 {
 675     env->scause = val;
 676     return 0;
 677 }
 678
 679 static int read_sbadaddr(CPURISCVState *env, int csrno, target_ulong *val)
 680 {
 681     *val = env->sbadaddr;
 682     return 0;
 683 }
 684
 685 static int write_sbadaddr(CPURISCVState *env, int csrno, target_ulong val)
 686 {
 687     env->sbadaddr = val;
 688     return 0;
 689 }
 690
 691 static int rmw_sip(CPURISCVState *env, int csrno, target_ulong *ret_value,
 692                    target_ulong new_value, target_ulong write_mask)
 693 {
 694     return rmw_mip(env, CSR_MSTATUS, ret_value, new_value,
 695                    write_mask & env->mideleg);
 696 }
 697
 698 /* Supervisor Protection and Translation */
 699 static int read_satp(CPURISCVState *env, int csrno, target_ulong *val)
 700 {
 701     if (!riscv_feature(env, RISCV_FEATURE_MMU)) {
 702         *val = 0;
 703     } else if (env->priv_ver >= PRIV_VERSION_1_10_0) {
 704         if (env->priv == PRV_S && get_field(env->mstatus, MSTATUS_TVM)) {
 705             return -1;
 706         } else {
 707             *val = env->satp;
 708         }
 709     } else {
 710         *val = env->sptbr;
 711     }
 712     return 0;
 713 }
 714
 715 static int write_satp(CPURISCVState *env, int csrno, target_ulong val)
 716 {
 717     if (!riscv_feature(env, RISCV_FEATURE_MMU)) {
 718         return 0;
 719     }
 720     if (env->priv_ver <= PRIV_VERSION_1_09_1 && (val ^ env->sptbr)) {
 721         tlb_flush(CPU(riscv_env_get_cpu(env)));
 722         env->sptbr = val & (((target_ulong)
 723             1 << (TARGET_PHYS_ADDR_SPACE_BITS - PGSHIFT)) - 1);
 724     }
 725     if (env->priv_ver >= PRIV_VERSION_1_10_0 &&
 726         validate_vm(env, get_field(val, SATP_MODE)) &&
 727         ((val ^ env->satp) & (SATP_MODE | SATP_ASID | SATP_PPN)))
 728     {
 729         if (env->priv == PRV_S && get_field(env->mstatus, MSTATUS_TVM)) {
 730             return -1;
 731         } else {
 732             tlb_flush(CPU(riscv_env_get_cpu(env)));
 733             env->satp = val;
 734         }
 735     }
 736     return 0;
 737 }
 738
 739 /* Physical Memory Protection */
 740 static int read_pmpcfg(CPURISCVState *env, int csrno, target_ulong *val)
 741 {
 742     *val = pmpcfg_csr_read(env, csrno - CSR_PMPCFG0);
 743     return 0;
 744 }
 745
 746 static int write_pmpcfg(CPURISCVState *env, int csrno, target_ulong val)
 747 {
 748     pmpcfg_csr_write(env, csrno - CSR_PMPCFG0, val);
 749     return 0;
 750 }
 751
 752 static int read_pmpaddr(CPURISCVState *env, int csrno, target_ulong *val)
 753 {
 754     *val = pmpaddr_csr_read(env, csrno - CSR_PMPADDR0);
 755     return 0;
 756 }
 757
 758 static int write_pmpaddr(CPURISCVState *env, int csrno, target_ulong val)
 759 {
 760     pmpaddr_csr_write(env, csrno - CSR_PMPADDR0, val);
 761     return 0;
 762 }
 763
 764 #endif
 765
 766 /*
 767  * riscv_csrrw - read and/or update control and status register
 768  *
 769  * csrr   <->  riscv_csrrw(env, csrno, ret_value, 0, 0);
 770  * csrrw  <->  riscv_csrrw(env, csrno, ret_value, value, -1);
 771  * csrrs  <->  riscv_csrrw(env, csrno, ret_value, -1, value);
 772  * csrrc  <->  riscv_csrrw(env, csrno, ret_value, 0, value);
 773  */
 774
 775 int riscv_csrrw(CPURISCVState *env, int csrno, target_ulong *ret_value,
 776                 target_ulong new_value, target_ulong write_mask)
 777 {
 778     int ret;
 779     target_ulong old_value;
 780
 781     /* check privileges and return -1 if check fails */
 782 #if !defined(CONFIG_USER_ONLY)
 783     int csr_priv = get_field(csrno, 0x300);
 784     int read_only = get_field(csrno, 0xC00) == 3;
 785     if ((write_mask && read_only) || (env->priv < csr_priv)) {
 786         return -1;
 787     }
 788 #endif
 789
 790     /* check predicate */
 791     if (!csr_ops[csrno].predicate || csr_ops[csrno].predicate(env, csrno) < 0) {
 792         return -1;
 793     }
 794
 795     /* execute combined read/write operation if it exists */
 796     if (csr_ops[csrno].op) {
 797         return csr_ops[csrno].op(env, csrno, ret_value, new_value, write_mask);
 798     }
 799
 800     /* if no accessor exists then return failure */
 801     if (!csr_ops[csrno].read) {
 802         return -1;
 803     }
 804
 805     /* read old value */
 806     ret = csr_ops[csrno].read(env, csrno, &old_value);
 807     if (ret < 0) {
 808         return ret;
 809     }
 810
 811     /* write value if writable and write mask set, otherwise drop writes */
 812     if (write_mask) {
 813         new_value = (old_value & ~write_mask) | (new_value & write_mask);
 814         if (csr_ops[csrno].write) {
 815             ret = csr_ops[csrno].write(env, csrno, new_value);
 816             if (ret < 0) {
 817                 return ret;
 818             }
 819         }
 820     }
 821
 822     /* return old value */
 823     if (ret_value) {
 824         *ret_value = old_value;
 825     }
 826
 827     return 0;
 828 }
 829
 830 /* Control and Status Register function table */
 831 static riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
 832     /* User Floating-Point CSRs */
 833     [CSR_FFLAGS] =              { fs,   read_fflags,      write_fflags      },
 834     [CSR_FRM] =                 { fs,   read_frm,         write_frm         },
 835     [CSR_FCSR] =                { fs,   read_fcsr,        write_fcsr        },
 836
 837     /* User Timers and Counters */
 838     [CSR_CYCLE] =               { ctr,  read_instret                        },
 839     [CSR_INSTRET] =             { ctr,  read_instret                        },
 840 #if defined(TARGET_RISCV32)
 841     [CSR_CYCLEH] =              { ctr,  read_instreth                       },
 842     [CSR_INSTRETH] =            { ctr,  read_instreth                       },
 843 #endif
 844
 845     /* User-level time CSRs are only available in linux-user
 846      * In privileged mode, the monitor emulates these CSRs */
 847 #if defined(CONFIG_USER_ONLY)
 848     [CSR_TIME] =                { ctr,  read_time                           },
 849 #if defined(TARGET_RISCV32)
 850     [CSR_TIMEH] =               { ctr,  read_timeh                          },
 851 #endif
 852 #endif
 853
 854 #if !defined(CONFIG_USER_ONLY)
 855     /* Machine Timers and Counters */
 856     [CSR_MCYCLE] =              { any,  read_instret                        },
 857     [CSR_MINSTRET] =            { any,  read_instret                        },
 858 #if defined(TARGET_RISCV32)
 859     [CSR_MCYCLEH] =             { any,  read_instreth                       },
 860     [CSR_MINSTRETH] =           { any,  read_instreth                       },
 861 #endif
 862
 863     /* Machine Information Registers */
 864     [CSR_MVENDORID] =           { any,  read_zero                           },
 865     [CSR_MARCHID] =             { any,  read_zero                           },
 866     [CSR_MIMPID] =              { any,  read_zero                           },
 867     [CSR_MHARTID] =             { any,  read_mhartid                        },
 868
 869     /* Machine Trap Setup */
 870     [CSR_MSTATUS] =             { any,  read_mstatus,     write_mstatus     },
 871     [CSR_MISA] =                { any,  read_misa,        write_misa        },
 872     [CSR_MIDELEG] =             { any,  read_mideleg,     write_mideleg     },
 873     [CSR_MEDELEG] =             { any,  read_medeleg,     write_medeleg     },
 874     [CSR_MIE] =                 { any,  read_mie,         write_mie         },
 875     [CSR_MTVEC] =               { any,  read_mtvec,       write_mtvec       },
 876     [CSR_MCOUNTEREN] =          { any,  read_mcounteren,  write_mcounteren  },
 877
 878     /* Legacy Counter Setup (priv v1.9.1) */
 879     [CSR_MUCOUNTEREN] =         { any,  read_mucounteren, write_mucounteren },
 880     [CSR_MSCOUNTEREN] =         { any,  read_mscounteren, write_mscounteren },
 881
 882     /* Machine Trap Handling */
 883     [CSR_MSCRATCH] =            { any,  read_mscratch,    write_mscratch    },
 884     [CSR_MEPC] =                { any,  read_mepc,        write_mepc        },
 885     [CSR_MCAUSE] =              { any,  read_mcause,      write_mcause      },
 886     [CSR_MBADADDR] =            { any,  read_mbadaddr,    write_mbadaddr    },
 887     [CSR_MIP] =                 { any,  NULL,     NULL,     rmw_mip         },
 888
 889     /* Supervisor Trap Setup */
 890     [CSR_SSTATUS] =             { smode, read_sstatus,     write_sstatus     },
 891     [CSR_SIE] =                 { smode, read_sie,         write_sie         },
 892     [CSR_STVEC] =               { smode, read_stvec,       write_stvec       },
 893     [CSR_SCOUNTEREN] =          { smode, read_scounteren,  write_scounteren  },
 894
 895     /* Supervisor Trap Handling */
 896     [CSR_SSCRATCH] =            { smode, read_sscratch,    write_sscratch    },
 897     [CSR_SEPC] =                { smode, read_sepc,        write_sepc        },
 898     [CSR_SCAUSE] =              { smode, read_scause,      write_scause      },
 899     [CSR_SBADADDR] =            { smode, read_sbadaddr,    write_sbadaddr    },
 900     [CSR_SIP] =                 { smode, NULL,     NULL,     rmw_sip         },
 901
 902     /* Supervisor Protection and Translation */
 903     [CSR_SATP] =                { smode, read_satp,        write_satp        },
 904
 905     /* Physical Memory Protection */
 906     [CSR_PMPCFG0  ... CSR_PMPADDR9] =  { pmp,   read_pmpcfg,  write_pmpcfg   },
 907     [CSR_PMPADDR0 ... CSR_PMPADDR15] = { pmp,   read_pmpaddr, write_pmpaddr  },
 908
 909     /* Performance Counters */
 910     [CSR_HPMCOUNTER3   ... CSR_HPMCOUNTER31] =    { ctr,  read_zero          },
 911     [CSR_MHPMCOUNTER3  ... CSR_MHPMCOUNTER31] =   { any,  read_zero          },
 912     [CSR_MHPMEVENT3    ... CSR_MHPMEVENT31] =     { any,  read_zero          },
 913 #if defined(TARGET_RISCV32)
 914     [CSR_HPMCOUNTER3H  ... CSR_HPMCOUNTER31H] =   { ctr,  read_zero          },
 915     [CSR_MHPMCOUNTER3H ... CSR_MHPMCOUNTER31H] =  { any,  read_zero          },
 916 #endif
 917 #endif /* !CONFIG_USER_ONLY */
 918 };