xref: /openbmc/qemu/target/riscv/csr.c (revision d0e53ce3)
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->debugger && !riscv_cpu_fp_enabled(env)) {
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     CPUState *cs = env_cpu(env);
60     RISCVCPU *cpu = RISCV_CPU(cs);
61     uint32_t ctr_en = ~0u;
62 
63     if (!cpu->cfg.ext_counters) {
64         /* The Counters extensions is not enabled */
65         return -1;
66     }
67 
68     /*
69      * The counters are always enabled at run time on newer priv specs, as the
70      * CSR has changed from controlling that the counters can be read to
71      * controlling that the counters increment.
72      */
73     if (env->priv_ver > PRIV_VERSION_1_09_1) {
74         return 0;
75     }
76 
77     if (env->priv < PRV_M) {
78         ctr_en &= env->mcounteren;
79     }
80     if (env->priv < PRV_S) {
81         ctr_en &= env->scounteren;
82     }
83     if (!(ctr_en & (1u << (csrno & 31)))) {
84         return -1;
85     }
86 #endif
87     return 0;
88 }
89 
90 #if !defined(CONFIG_USER_ONLY)
91 static int any(CPURISCVState *env, int csrno)
92 {
93     return 0;
94 }
95 
96 static int smode(CPURISCVState *env, int csrno)
97 {
98     return -!riscv_has_ext(env, RVS);
99 }
100 
101 static int hmode(CPURISCVState *env, int csrno)
102 {
103     if (riscv_has_ext(env, RVS) &&
104         riscv_has_ext(env, RVH)) {
105         /* Hypervisor extension is supported */
106         if ((env->priv == PRV_S && !riscv_cpu_virt_enabled(env)) ||
107             env->priv == PRV_M) {
108             return 0;
109         }
110     }
111 
112     return -1;
113 }
114 
115 static int pmp(CPURISCVState *env, int csrno)
116 {
117     return -!riscv_feature(env, RISCV_FEATURE_PMP);
118 }
119 #endif
120 
121 /* User Floating-Point CSRs */
122 static int read_fflags(CPURISCVState *env, int csrno, target_ulong *val)
123 {
124 #if !defined(CONFIG_USER_ONLY)
125     if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
126         return -1;
127     }
128 #endif
129     *val = riscv_cpu_get_fflags(env);
130     return 0;
131 }
132 
133 static int write_fflags(CPURISCVState *env, int csrno, target_ulong val)
134 {
135 #if !defined(CONFIG_USER_ONLY)
136     if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
137         return -1;
138     }
139     env->mstatus |= MSTATUS_FS;
140 #endif
141     riscv_cpu_set_fflags(env, val & (FSR_AEXC >> FSR_AEXC_SHIFT));
142     return 0;
143 }
144 
145 static int read_frm(CPURISCVState *env, int csrno, target_ulong *val)
146 {
147 #if !defined(CONFIG_USER_ONLY)
148     if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
149         return -1;
150     }
151 #endif
152     *val = env->frm;
153     return 0;
154 }
155 
156 static int write_frm(CPURISCVState *env, int csrno, target_ulong val)
157 {
158 #if !defined(CONFIG_USER_ONLY)
159     if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
160         return -1;
161     }
162     env->mstatus |= MSTATUS_FS;
163 #endif
164     env->frm = val & (FSR_RD >> FSR_RD_SHIFT);
165     return 0;
166 }
167 
168 static int read_fcsr(CPURISCVState *env, int csrno, target_ulong *val)
169 {
170 #if !defined(CONFIG_USER_ONLY)
171     if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
172         return -1;
173     }
174 #endif
175     *val = (riscv_cpu_get_fflags(env) << FSR_AEXC_SHIFT)
176         | (env->frm << FSR_RD_SHIFT);
177     return 0;
178 }
179 
180 static int write_fcsr(CPURISCVState *env, int csrno, target_ulong val)
181 {
182 #if !defined(CONFIG_USER_ONLY)
183     if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
184         return -1;
185     }
186     env->mstatus |= MSTATUS_FS;
187 #endif
188     env->frm = (val & FSR_RD) >> FSR_RD_SHIFT;
189     riscv_cpu_set_fflags(env, (val & FSR_AEXC) >> FSR_AEXC_SHIFT);
190     return 0;
191 }
192 
193 /* User Timers and Counters */
194 static int read_instret(CPURISCVState *env, int csrno, target_ulong *val)
195 {
196 #if !defined(CONFIG_USER_ONLY)
197     if (use_icount) {
198         *val = cpu_get_icount();
199     } else {
200         *val = cpu_get_host_ticks();
201     }
202 #else
203     *val = cpu_get_host_ticks();
204 #endif
205     return 0;
206 }
207 
208 #if defined(TARGET_RISCV32)
209 static int read_instreth(CPURISCVState *env, int csrno, target_ulong *val)
210 {
211 #if !defined(CONFIG_USER_ONLY)
212     if (use_icount) {
213         *val = cpu_get_icount() >> 32;
214     } else {
215         *val = cpu_get_host_ticks() >> 32;
216     }
217 #else
218     *val = cpu_get_host_ticks() >> 32;
219 #endif
220     return 0;
221 }
222 #endif /* TARGET_RISCV32 */
223 
224 #if defined(CONFIG_USER_ONLY)
225 static int read_time(CPURISCVState *env, int csrno, target_ulong *val)
226 {
227     *val = cpu_get_host_ticks();
228     return 0;
229 }
230 
231 #if defined(TARGET_RISCV32)
232 static int read_timeh(CPURISCVState *env, int csrno, target_ulong *val)
233 {
234     *val = cpu_get_host_ticks() >> 32;
235     return 0;
236 }
237 #endif
238 
239 #else /* CONFIG_USER_ONLY */
240 
241 /* Machine constants */
242 
243 #define M_MODE_INTERRUPTS  (MIP_MSIP | MIP_MTIP | MIP_MEIP)
244 #define S_MODE_INTERRUPTS  (MIP_SSIP | MIP_STIP | MIP_SEIP)
245 #define VS_MODE_INTERRUPTS (MIP_VSSIP | MIP_VSTIP | MIP_VSEIP)
246 
247 static const target_ulong delegable_ints = S_MODE_INTERRUPTS |
248                                            VS_MODE_INTERRUPTS;
249 static const target_ulong all_ints = M_MODE_INTERRUPTS | S_MODE_INTERRUPTS |
250                                      VS_MODE_INTERRUPTS;
251 static const target_ulong delegable_excps =
252     (1ULL << (RISCV_EXCP_INST_ADDR_MIS)) |
253     (1ULL << (RISCV_EXCP_INST_ACCESS_FAULT)) |
254     (1ULL << (RISCV_EXCP_ILLEGAL_INST)) |
255     (1ULL << (RISCV_EXCP_BREAKPOINT)) |
256     (1ULL << (RISCV_EXCP_LOAD_ADDR_MIS)) |
257     (1ULL << (RISCV_EXCP_LOAD_ACCESS_FAULT)) |
258     (1ULL << (RISCV_EXCP_STORE_AMO_ADDR_MIS)) |
259     (1ULL << (RISCV_EXCP_STORE_AMO_ACCESS_FAULT)) |
260     (1ULL << (RISCV_EXCP_U_ECALL)) |
261     (1ULL << (RISCV_EXCP_S_ECALL)) |
262     (1ULL << (RISCV_EXCP_VS_ECALL)) |
263     (1ULL << (RISCV_EXCP_M_ECALL)) |
264     (1ULL << (RISCV_EXCP_INST_PAGE_FAULT)) |
265     (1ULL << (RISCV_EXCP_LOAD_PAGE_FAULT)) |
266     (1ULL << (RISCV_EXCP_STORE_PAGE_FAULT)) |
267     (1ULL << (RISCV_EXCP_INST_GUEST_PAGE_FAULT)) |
268     (1ULL << (RISCV_EXCP_LOAD_GUEST_ACCESS_FAULT)) |
269     (1ULL << (RISCV_EXCP_STORE_GUEST_AMO_ACCESS_FAULT));
270 static const target_ulong sstatus_v1_9_mask = SSTATUS_SIE | SSTATUS_SPIE |
271     SSTATUS_UIE | SSTATUS_UPIE | SSTATUS_SPP | SSTATUS_FS | SSTATUS_XS |
272     SSTATUS_SUM | SSTATUS_SD;
273 static const target_ulong sstatus_v1_10_mask = SSTATUS_SIE | SSTATUS_SPIE |
274     SSTATUS_UIE | SSTATUS_UPIE | SSTATUS_SPP | SSTATUS_FS | SSTATUS_XS |
275     SSTATUS_SUM | SSTATUS_MXR | SSTATUS_SD;
276 static const target_ulong sip_writable_mask = SIP_SSIP | MIP_USIP | MIP_UEIP;
277 static const target_ulong hip_writable_mask = MIP_VSSIP | MIP_VSTIP | MIP_VSEIP;
278 static const target_ulong vsip_writable_mask = MIP_VSSIP;
279 
280 #if defined(TARGET_RISCV32)
281 static const char valid_vm_1_09[16] = {
282     [VM_1_09_MBARE] = 1,
283     [VM_1_09_SV32] = 1,
284 };
285 static const char valid_vm_1_10[16] = {
286     [VM_1_10_MBARE] = 1,
287     [VM_1_10_SV32] = 1
288 };
289 #elif defined(TARGET_RISCV64)
290 static const char valid_vm_1_09[16] = {
291     [VM_1_09_MBARE] = 1,
292     [VM_1_09_SV39] = 1,
293     [VM_1_09_SV48] = 1,
294 };
295 static const char valid_vm_1_10[16] = {
296     [VM_1_10_MBARE] = 1,
297     [VM_1_10_SV39] = 1,
298     [VM_1_10_SV48] = 1,
299     [VM_1_10_SV57] = 1
300 };
301 #endif /* CONFIG_USER_ONLY */
302 
303 /* Machine Information Registers */
304 static int read_zero(CPURISCVState *env, int csrno, target_ulong *val)
305 {
306     return *val = 0;
307 }
308 
309 static int read_mhartid(CPURISCVState *env, int csrno, target_ulong *val)
310 {
311     *val = env->mhartid;
312     return 0;
313 }
314 
315 /* Machine Trap Setup */
316 static int read_mstatus(CPURISCVState *env, int csrno, target_ulong *val)
317 {
318     *val = env->mstatus;
319     return 0;
320 }
321 
322 static int validate_vm(CPURISCVState *env, target_ulong vm)
323 {
324     return (env->priv_ver >= PRIV_VERSION_1_10_0) ?
325         valid_vm_1_10[vm & 0xf] : valid_vm_1_09[vm & 0xf];
326 }
327 
328 static int write_mstatus(CPURISCVState *env, int csrno, target_ulong val)
329 {
330     target_ulong mstatus = env->mstatus;
331     target_ulong mask = 0;
332     int dirty;
333 
334     /* flush tlb on mstatus fields that affect VM */
335     if (env->priv_ver <= PRIV_VERSION_1_09_1) {
336         if ((val ^ mstatus) & (MSTATUS_MXR | MSTATUS_MPP |
337                 MSTATUS_MPRV | MSTATUS_SUM | MSTATUS_VM)) {
338             tlb_flush(env_cpu(env));
339         }
340         mask = MSTATUS_SIE | MSTATUS_SPIE | MSTATUS_MIE | MSTATUS_MPIE |
341             MSTATUS_SPP | MSTATUS_FS | MSTATUS_MPRV | MSTATUS_SUM |
342             MSTATUS_MPP | MSTATUS_MXR |
343             (validate_vm(env, get_field(val, MSTATUS_VM)) ?
344                 MSTATUS_VM : 0);
345     }
346     if (env->priv_ver >= PRIV_VERSION_1_10_0) {
347         if ((val ^ mstatus) & (MSTATUS_MXR | MSTATUS_MPP | MSTATUS_MPV |
348                 MSTATUS_MPRV | MSTATUS_SUM)) {
349             tlb_flush(env_cpu(env));
350         }
351         mask = MSTATUS_SIE | MSTATUS_SPIE | MSTATUS_MIE | MSTATUS_MPIE |
352             MSTATUS_SPP | MSTATUS_FS | MSTATUS_MPRV | MSTATUS_SUM |
353             MSTATUS_MPP | MSTATUS_MXR | MSTATUS_TVM | MSTATUS_TSR |
354             MSTATUS_TW;
355 #if defined(TARGET_RISCV64)
356             /*
357              * RV32: MPV and MTL are not in mstatus. The current plan is to
358              * add them to mstatush. For now, we just don't support it.
359              */
360             mask |= MSTATUS_MTL | MSTATUS_MPV;
361 #endif
362     }
363 
364     mstatus = (mstatus & ~mask) | (val & mask);
365 
366     dirty = ((mstatus & MSTATUS_FS) == MSTATUS_FS) |
367             ((mstatus & MSTATUS_XS) == MSTATUS_XS);
368     mstatus = set_field(mstatus, MSTATUS_SD, dirty);
369     env->mstatus = mstatus;
370 
371     return 0;
372 }
373 
374 static int read_misa(CPURISCVState *env, int csrno, target_ulong *val)
375 {
376     *val = env->misa;
377     return 0;
378 }
379 
380 static int write_misa(CPURISCVState *env, int csrno, target_ulong val)
381 {
382     if (!riscv_feature(env, RISCV_FEATURE_MISA)) {
383         /* drop write to misa */
384         return 0;
385     }
386 
387     /* 'I' or 'E' must be present */
388     if (!(val & (RVI | RVE))) {
389         /* It is not, drop write to misa */
390         return 0;
391     }
392 
393     /* 'E' excludes all other extensions */
394     if (val & RVE) {
395         /* when we support 'E' we can do "val = RVE;" however
396          * for now we just drop writes if 'E' is present.
397          */
398         return 0;
399     }
400 
401     /* Mask extensions that are not supported by this hart */
402     val &= env->misa_mask;
403 
404     /* Mask extensions that are not supported by QEMU */
405     val &= (RVI | RVE | RVM | RVA | RVF | RVD | RVC | RVS | RVU);
406 
407     /* 'D' depends on 'F', so clear 'D' if 'F' is not present */
408     if ((val & RVD) && !(val & RVF)) {
409         val &= ~RVD;
410     }
411 
412     /* Suppress 'C' if next instruction is not aligned
413      * TODO: this should check next_pc
414      */
415     if ((val & RVC) && (GETPC() & ~3) != 0) {
416         val &= ~RVC;
417     }
418 
419     /* misa.MXL writes are not supported by QEMU */
420     val = (env->misa & MISA_MXL) | (val & ~MISA_MXL);
421 
422     /* flush translation cache */
423     if (val != env->misa) {
424         tb_flush(env_cpu(env));
425     }
426 
427     env->misa = val;
428 
429     return 0;
430 }
431 
432 static int read_medeleg(CPURISCVState *env, int csrno, target_ulong *val)
433 {
434     *val = env->medeleg;
435     return 0;
436 }
437 
438 static int write_medeleg(CPURISCVState *env, int csrno, target_ulong val)
439 {
440     env->medeleg = (env->medeleg & ~delegable_excps) | (val & delegable_excps);
441     return 0;
442 }
443 
444 static int read_mideleg(CPURISCVState *env, int csrno, target_ulong *val)
445 {
446     *val = env->mideleg;
447     return 0;
448 }
449 
450 static int write_mideleg(CPURISCVState *env, int csrno, target_ulong val)
451 {
452     env->mideleg = (env->mideleg & ~delegable_ints) | (val & delegable_ints);
453     if (riscv_has_ext(env, RVH)) {
454         env->mideleg |= VS_MODE_INTERRUPTS;
455     }
456     return 0;
457 }
458 
459 static int read_mie(CPURISCVState *env, int csrno, target_ulong *val)
460 {
461     *val = env->mie;
462     return 0;
463 }
464 
465 static int write_mie(CPURISCVState *env, int csrno, target_ulong val)
466 {
467     env->mie = (env->mie & ~all_ints) | (val & all_ints);
468     return 0;
469 }
470 
471 static int read_mtvec(CPURISCVState *env, int csrno, target_ulong *val)
472 {
473     *val = env->mtvec;
474     return 0;
475 }
476 
477 static int write_mtvec(CPURISCVState *env, int csrno, target_ulong val)
478 {
479     /* bits [1:0] encode mode; 0 = direct, 1 = vectored, 2 >= reserved */
480     if ((val & 3) < 2) {
481         env->mtvec = val;
482     } else {
483         qemu_log_mask(LOG_UNIMP, "CSR_MTVEC: reserved mode not supported\n");
484     }
485     return 0;
486 }
487 
488 static int read_mcounteren(CPURISCVState *env, int csrno, target_ulong *val)
489 {
490     if (env->priv_ver < PRIV_VERSION_1_10_0) {
491         return -1;
492     }
493     *val = env->mcounteren;
494     return 0;
495 }
496 
497 static int write_mcounteren(CPURISCVState *env, int csrno, target_ulong val)
498 {
499     if (env->priv_ver < PRIV_VERSION_1_10_0) {
500         return -1;
501     }
502     env->mcounteren = val;
503     return 0;
504 }
505 
506 /* This regiser is replaced with CSR_MCOUNTINHIBIT in 1.11.0 */
507 static int read_mscounteren(CPURISCVState *env, int csrno, target_ulong *val)
508 {
509     if (env->priv_ver > PRIV_VERSION_1_09_1
510         && env->priv_ver < PRIV_VERSION_1_11_0) {
511         return -1;
512     }
513     *val = env->mcounteren;
514     return 0;
515 }
516 
517 /* This regiser is replaced with CSR_MCOUNTINHIBIT in 1.11.0 */
518 static int write_mscounteren(CPURISCVState *env, int csrno, target_ulong val)
519 {
520     if (env->priv_ver > PRIV_VERSION_1_09_1
521         && env->priv_ver < PRIV_VERSION_1_11_0) {
522         return -1;
523     }
524     env->mcounteren = val;
525     return 0;
526 }
527 
528 static int read_mucounteren(CPURISCVState *env, int csrno, target_ulong *val)
529 {
530     if (env->priv_ver > PRIV_VERSION_1_09_1) {
531         return -1;
532     }
533     *val = env->scounteren;
534     return 0;
535 }
536 
537 static int write_mucounteren(CPURISCVState *env, int csrno, target_ulong val)
538 {
539     if (env->priv_ver > PRIV_VERSION_1_09_1) {
540         return -1;
541     }
542     env->scounteren = val;
543     return 0;
544 }
545 
546 /* Machine Trap Handling */
547 static int read_mscratch(CPURISCVState *env, int csrno, target_ulong *val)
548 {
549     *val = env->mscratch;
550     return 0;
551 }
552 
553 static int write_mscratch(CPURISCVState *env, int csrno, target_ulong val)
554 {
555     env->mscratch = val;
556     return 0;
557 }
558 
559 static int read_mepc(CPURISCVState *env, int csrno, target_ulong *val)
560 {
561     *val = env->mepc;
562     return 0;
563 }
564 
565 static int write_mepc(CPURISCVState *env, int csrno, target_ulong val)
566 {
567     env->mepc = val;
568     return 0;
569 }
570 
571 static int read_mcause(CPURISCVState *env, int csrno, target_ulong *val)
572 {
573     *val = env->mcause;
574     return 0;
575 }
576 
577 static int write_mcause(CPURISCVState *env, int csrno, target_ulong val)
578 {
579     env->mcause = val;
580     return 0;
581 }
582 
583 static int read_mbadaddr(CPURISCVState *env, int csrno, target_ulong *val)
584 {
585     *val = env->mbadaddr;
586     return 0;
587 }
588 
589 static int write_mbadaddr(CPURISCVState *env, int csrno, target_ulong val)
590 {
591     env->mbadaddr = val;
592     return 0;
593 }
594 
595 static int rmw_mip(CPURISCVState *env, int csrno, target_ulong *ret_value,
596                    target_ulong new_value, target_ulong write_mask)
597 {
598     RISCVCPU *cpu = env_archcpu(env);
599     /* Allow software control of delegable interrupts not claimed by hardware */
600     target_ulong mask = write_mask & delegable_ints & ~env->miclaim;
601     uint32_t old_mip;
602 
603     if (mask) {
604         old_mip = riscv_cpu_update_mip(cpu, mask, (new_value & mask));
605     } else {
606         old_mip = env->mip;
607     }
608 
609     if (ret_value) {
610         *ret_value = old_mip;
611     }
612 
613     return 0;
614 }
615 
616 /* Supervisor Trap Setup */
617 static int read_sstatus(CPURISCVState *env, int csrno, target_ulong *val)
618 {
619     target_ulong mask = ((env->priv_ver >= PRIV_VERSION_1_10_0) ?
620                          sstatus_v1_10_mask : sstatus_v1_9_mask);
621     *val = env->mstatus & mask;
622     return 0;
623 }
624 
625 static int write_sstatus(CPURISCVState *env, int csrno, target_ulong val)
626 {
627     target_ulong mask = ((env->priv_ver >= PRIV_VERSION_1_10_0) ?
628                          sstatus_v1_10_mask : sstatus_v1_9_mask);
629     target_ulong newval = (env->mstatus & ~mask) | (val & mask);
630     return write_mstatus(env, CSR_MSTATUS, newval);
631 }
632 
633 static int read_sie(CPURISCVState *env, int csrno, target_ulong *val)
634 {
635     if (riscv_cpu_virt_enabled(env)) {
636         /* Tell the guest the VS bits, shifted to the S bit locations */
637         *val = (env->mie & env->mideleg & VS_MODE_INTERRUPTS) >> 1;
638     } else {
639         *val = env->mie & env->mideleg;
640     }
641     return 0;
642 }
643 
644 static int write_sie(CPURISCVState *env, int csrno, target_ulong val)
645 {
646     target_ulong newval;
647 
648     if (riscv_cpu_virt_enabled(env)) {
649         /* Shift the guests S bits to VS */
650         newval = (env->mie & ~VS_MODE_INTERRUPTS) |
651                  ((val << 1) & VS_MODE_INTERRUPTS);
652     } else {
653         newval = (env->mie & ~S_MODE_INTERRUPTS) | (val & S_MODE_INTERRUPTS);
654     }
655 
656     return write_mie(env, CSR_MIE, newval);
657 }
658 
659 static int read_stvec(CPURISCVState *env, int csrno, target_ulong *val)
660 {
661     *val = env->stvec;
662     return 0;
663 }
664 
665 static int write_stvec(CPURISCVState *env, int csrno, target_ulong val)
666 {
667     /* bits [1:0] encode mode; 0 = direct, 1 = vectored, 2 >= reserved */
668     if ((val & 3) < 2) {
669         env->stvec = val;
670     } else {
671         qemu_log_mask(LOG_UNIMP, "CSR_STVEC: reserved mode not supported\n");
672     }
673     return 0;
674 }
675 
676 static int read_scounteren(CPURISCVState *env, int csrno, target_ulong *val)
677 {
678     if (env->priv_ver < PRIV_VERSION_1_10_0) {
679         return -1;
680     }
681     *val = env->scounteren;
682     return 0;
683 }
684 
685 static int write_scounteren(CPURISCVState *env, int csrno, target_ulong val)
686 {
687     if (env->priv_ver < PRIV_VERSION_1_10_0) {
688         return -1;
689     }
690     env->scounteren = val;
691     return 0;
692 }
693 
694 /* Supervisor Trap Handling */
695 static int read_sscratch(CPURISCVState *env, int csrno, target_ulong *val)
696 {
697     *val = env->sscratch;
698     return 0;
699 }
700 
701 static int write_sscratch(CPURISCVState *env, int csrno, target_ulong val)
702 {
703     env->sscratch = val;
704     return 0;
705 }
706 
707 static int read_sepc(CPURISCVState *env, int csrno, target_ulong *val)
708 {
709     *val = env->sepc;
710     return 0;
711 }
712 
713 static int write_sepc(CPURISCVState *env, int csrno, target_ulong val)
714 {
715     env->sepc = val;
716     return 0;
717 }
718 
719 static int read_scause(CPURISCVState *env, int csrno, target_ulong *val)
720 {
721     *val = env->scause;
722     return 0;
723 }
724 
725 static int write_scause(CPURISCVState *env, int csrno, target_ulong val)
726 {
727     env->scause = val;
728     return 0;
729 }
730 
731 static int read_sbadaddr(CPURISCVState *env, int csrno, target_ulong *val)
732 {
733     *val = env->sbadaddr;
734     return 0;
735 }
736 
737 static int write_sbadaddr(CPURISCVState *env, int csrno, target_ulong val)
738 {
739     env->sbadaddr = val;
740     return 0;
741 }
742 
743 static int rmw_sip(CPURISCVState *env, int csrno, target_ulong *ret_value,
744                    target_ulong new_value, target_ulong write_mask)
745 {
746     int ret = rmw_mip(env, CSR_MSTATUS, ret_value, new_value,
747                       write_mask & env->mideleg & sip_writable_mask);
748     *ret_value &= env->mideleg;
749     return ret;
750 }
751 
752 /* Supervisor Protection and Translation */
753 static int read_satp(CPURISCVState *env, int csrno, target_ulong *val)
754 {
755     if (!riscv_feature(env, RISCV_FEATURE_MMU)) {
756         *val = 0;
757     } else if (env->priv_ver >= PRIV_VERSION_1_10_0) {
758         if (env->priv == PRV_S && get_field(env->mstatus, MSTATUS_TVM)) {
759             return -1;
760         } else {
761             *val = env->satp;
762         }
763     } else {
764         *val = env->sptbr;
765     }
766     return 0;
767 }
768 
769 static int write_satp(CPURISCVState *env, int csrno, target_ulong val)
770 {
771     if (!riscv_feature(env, RISCV_FEATURE_MMU)) {
772         return 0;
773     }
774     if (env->priv_ver <= PRIV_VERSION_1_09_1 && (val ^ env->sptbr)) {
775         tlb_flush(env_cpu(env));
776         env->sptbr = val & (((target_ulong)
777             1 << (TARGET_PHYS_ADDR_SPACE_BITS - PGSHIFT)) - 1);
778     }
779     if (env->priv_ver >= PRIV_VERSION_1_10_0 &&
780         validate_vm(env, get_field(val, SATP_MODE)) &&
781         ((val ^ env->satp) & (SATP_MODE | SATP_ASID | SATP_PPN)))
782     {
783         if (env->priv == PRV_S && get_field(env->mstatus, MSTATUS_TVM)) {
784             return -1;
785         } else {
786             if((val ^ env->satp) & SATP_ASID) {
787                 tlb_flush(env_cpu(env));
788             }
789             env->satp = val;
790         }
791     }
792     return 0;
793 }
794 
795 /* Hypervisor Extensions */
796 static int read_hstatus(CPURISCVState *env, int csrno, target_ulong *val)
797 {
798     *val = env->hstatus;
799     return 0;
800 }
801 
802 static int write_hstatus(CPURISCVState *env, int csrno, target_ulong val)
803 {
804     env->hstatus = val;
805     return 0;
806 }
807 
808 static int read_hedeleg(CPURISCVState *env, int csrno, target_ulong *val)
809 {
810     *val = env->hedeleg;
811     return 0;
812 }
813 
814 static int write_hedeleg(CPURISCVState *env, int csrno, target_ulong val)
815 {
816     env->hedeleg = val;
817     return 0;
818 }
819 
820 static int read_hideleg(CPURISCVState *env, int csrno, target_ulong *val)
821 {
822     *val = env->hideleg;
823     return 0;
824 }
825 
826 static int write_hideleg(CPURISCVState *env, int csrno, target_ulong val)
827 {
828     env->hideleg = val;
829     return 0;
830 }
831 
832 static int rmw_hip(CPURISCVState *env, int csrno, target_ulong *ret_value,
833                    target_ulong new_value, target_ulong write_mask)
834 {
835     int ret = rmw_mip(env, 0, ret_value, new_value,
836                       write_mask & hip_writable_mask);
837 
838     return ret;
839 }
840 
841 static int read_hie(CPURISCVState *env, int csrno, target_ulong *val)
842 {
843     *val = env->mie & VS_MODE_INTERRUPTS;
844     return 0;
845 }
846 
847 static int write_hie(CPURISCVState *env, int csrno, target_ulong val)
848 {
849     target_ulong newval = (env->mie & ~VS_MODE_INTERRUPTS) | (val & VS_MODE_INTERRUPTS);
850     return write_mie(env, CSR_MIE, newval);
851 }
852 
853 static int read_hcounteren(CPURISCVState *env, int csrno, target_ulong *val)
854 {
855     *val = env->hcounteren;
856     return 0;
857 }
858 
859 static int write_hcounteren(CPURISCVState *env, int csrno, target_ulong val)
860 {
861     env->hcounteren = val;
862     return 0;
863 }
864 
865 static int read_htval(CPURISCVState *env, int csrno, target_ulong *val)
866 {
867     *val = env->htval;
868     return 0;
869 }
870 
871 static int write_htval(CPURISCVState *env, int csrno, target_ulong val)
872 {
873     env->htval = val;
874     return 0;
875 }
876 
877 static int read_htinst(CPURISCVState *env, int csrno, target_ulong *val)
878 {
879     *val = env->htinst;
880     return 0;
881 }
882 
883 static int write_htinst(CPURISCVState *env, int csrno, target_ulong val)
884 {
885     env->htinst = val;
886     return 0;
887 }
888 
889 static int read_hgatp(CPURISCVState *env, int csrno, target_ulong *val)
890 {
891     *val = env->hgatp;
892     return 0;
893 }
894 
895 static int write_hgatp(CPURISCVState *env, int csrno, target_ulong val)
896 {
897     env->hgatp = val;
898     return 0;
899 }
900 
901 /* Virtual CSR Registers */
902 static int read_vsstatus(CPURISCVState *env, int csrno, target_ulong *val)
903 {
904     *val = env->vsstatus;
905     return 0;
906 }
907 
908 static int write_vsstatus(CPURISCVState *env, int csrno, target_ulong val)
909 {
910     env->vsstatus = val;
911     return 0;
912 }
913 
914 static int rmw_vsip(CPURISCVState *env, int csrno, target_ulong *ret_value,
915                     target_ulong new_value, target_ulong write_mask)
916 {
917     int ret = rmw_mip(env, 0, ret_value, new_value,
918                       write_mask & env->mideleg & vsip_writable_mask);
919     return ret;
920 }
921 
922 static int read_vsie(CPURISCVState *env, int csrno, target_ulong *val)
923 {
924     *val = env->mie & env->mideleg & VS_MODE_INTERRUPTS;
925     return 0;
926 }
927 
928 static int write_vsie(CPURISCVState *env, int csrno, target_ulong val)
929 {
930     target_ulong newval = (env->mie & ~env->mideleg) | (val & env->mideleg & MIP_VSSIP);
931     return write_mie(env, CSR_MIE, newval);
932 }
933 
934 static int read_vstvec(CPURISCVState *env, int csrno, target_ulong *val)
935 {
936     *val = env->vstvec;
937     return 0;
938 }
939 
940 static int write_vstvec(CPURISCVState *env, int csrno, target_ulong val)
941 {
942     env->vstvec = val;
943     return 0;
944 }
945 
946 static int read_vsscratch(CPURISCVState *env, int csrno, target_ulong *val)
947 {
948     *val = env->vsscratch;
949     return 0;
950 }
951 
952 static int write_vsscratch(CPURISCVState *env, int csrno, target_ulong val)
953 {
954     env->vsscratch = val;
955     return 0;
956 }
957 
958 static int read_vsepc(CPURISCVState *env, int csrno, target_ulong *val)
959 {
960     *val = env->vsepc;
961     return 0;
962 }
963 
964 static int write_vsepc(CPURISCVState *env, int csrno, target_ulong val)
965 {
966     env->vsepc = val;
967     return 0;
968 }
969 
970 static int read_vscause(CPURISCVState *env, int csrno, target_ulong *val)
971 {
972     *val = env->vscause;
973     return 0;
974 }
975 
976 static int write_vscause(CPURISCVState *env, int csrno, target_ulong val)
977 {
978     env->vscause = val;
979     return 0;
980 }
981 
982 static int read_vstval(CPURISCVState *env, int csrno, target_ulong *val)
983 {
984     *val = env->vstval;
985     return 0;
986 }
987 
988 static int write_vstval(CPURISCVState *env, int csrno, target_ulong val)
989 {
990     env->vstval = val;
991     return 0;
992 }
993 
994 static int read_vsatp(CPURISCVState *env, int csrno, target_ulong *val)
995 {
996     *val = env->vsatp;
997     return 0;
998 }
999 
1000 static int write_vsatp(CPURISCVState *env, int csrno, target_ulong val)
1001 {
1002     env->vsatp = val;
1003     return 0;
1004 }
1005 
1006 static int read_mtval2(CPURISCVState *env, int csrno, target_ulong *val)
1007 {
1008     *val = env->mtval2;
1009     return 0;
1010 }
1011 
1012 static int write_mtval2(CPURISCVState *env, int csrno, target_ulong val)
1013 {
1014     env->mtval2 = val;
1015     return 0;
1016 }
1017 
1018 static int read_mtinst(CPURISCVState *env, int csrno, target_ulong *val)
1019 {
1020     *val = env->mtinst;
1021     return 0;
1022 }
1023 
1024 static int write_mtinst(CPURISCVState *env, int csrno, target_ulong val)
1025 {
1026     env->mtinst = val;
1027     return 0;
1028 }
1029 
1030 /* Physical Memory Protection */
1031 static int read_pmpcfg(CPURISCVState *env, int csrno, target_ulong *val)
1032 {
1033     *val = pmpcfg_csr_read(env, csrno - CSR_PMPCFG0);
1034     return 0;
1035 }
1036 
1037 static int write_pmpcfg(CPURISCVState *env, int csrno, target_ulong val)
1038 {
1039     pmpcfg_csr_write(env, csrno - CSR_PMPCFG0, val);
1040     return 0;
1041 }
1042 
1043 static int read_pmpaddr(CPURISCVState *env, int csrno, target_ulong *val)
1044 {
1045     *val = pmpaddr_csr_read(env, csrno - CSR_PMPADDR0);
1046     return 0;
1047 }
1048 
1049 static int write_pmpaddr(CPURISCVState *env, int csrno, target_ulong val)
1050 {
1051     pmpaddr_csr_write(env, csrno - CSR_PMPADDR0, val);
1052     return 0;
1053 }
1054 
1055 #endif
1056 
1057 /*
1058  * riscv_csrrw - read and/or update control and status register
1059  *
1060  * csrr   <->  riscv_csrrw(env, csrno, ret_value, 0, 0);
1061  * csrrw  <->  riscv_csrrw(env, csrno, ret_value, value, -1);
1062  * csrrs  <->  riscv_csrrw(env, csrno, ret_value, -1, value);
1063  * csrrc  <->  riscv_csrrw(env, csrno, ret_value, 0, value);
1064  */
1065 
1066 int riscv_csrrw(CPURISCVState *env, int csrno, target_ulong *ret_value,
1067                 target_ulong new_value, target_ulong write_mask)
1068 {
1069     int ret;
1070     target_ulong old_value;
1071     RISCVCPU *cpu = env_archcpu(env);
1072 
1073     /* check privileges and return -1 if check fails */
1074 #if !defined(CONFIG_USER_ONLY)
1075     int effective_priv = env->priv;
1076     int read_only = get_field(csrno, 0xC00) == 3;
1077 
1078     if (riscv_has_ext(env, RVH) &&
1079         env->priv == PRV_S &&
1080         !riscv_cpu_virt_enabled(env)) {
1081         /*
1082          * We are in S mode without virtualisation, therefore we are in HS Mode.
1083          * Add 1 to the effective privledge level to allow us to access the
1084          * Hypervisor CSRs.
1085          */
1086         effective_priv++;
1087     }
1088 
1089     if ((write_mask && read_only) ||
1090         (!env->debugger && (effective_priv < get_field(csrno, 0x300)))) {
1091         return -1;
1092     }
1093 #endif
1094 
1095     /* ensure the CSR extension is enabled. */
1096     if (!cpu->cfg.ext_icsr) {
1097         return -1;
1098     }
1099 
1100     /* check predicate */
1101     if (!csr_ops[csrno].predicate || csr_ops[csrno].predicate(env, csrno) < 0) {
1102         return -1;
1103     }
1104 
1105     /* execute combined read/write operation if it exists */
1106     if (csr_ops[csrno].op) {
1107         return csr_ops[csrno].op(env, csrno, ret_value, new_value, write_mask);
1108     }
1109 
1110     /* if no accessor exists then return failure */
1111     if (!csr_ops[csrno].read) {
1112         return -1;
1113     }
1114 
1115     /* read old value */
1116     ret = csr_ops[csrno].read(env, csrno, &old_value);
1117     if (ret < 0) {
1118         return ret;
1119     }
1120 
1121     /* write value if writable and write mask set, otherwise drop writes */
1122     if (write_mask) {
1123         new_value = (old_value & ~write_mask) | (new_value & write_mask);
1124         if (csr_ops[csrno].write) {
1125             ret = csr_ops[csrno].write(env, csrno, new_value);
1126             if (ret < 0) {
1127                 return ret;
1128             }
1129         }
1130     }
1131 
1132     /* return old value */
1133     if (ret_value) {
1134         *ret_value = old_value;
1135     }
1136 
1137     return 0;
1138 }
1139 
1140 /*
1141  * Debugger support.  If not in user mode, set env->debugger before the
1142  * riscv_csrrw call and clear it after the call.
1143  */
1144 int riscv_csrrw_debug(CPURISCVState *env, int csrno, target_ulong *ret_value,
1145                 target_ulong new_value, target_ulong write_mask)
1146 {
1147     int ret;
1148 #if !defined(CONFIG_USER_ONLY)
1149     env->debugger = true;
1150 #endif
1151     ret = riscv_csrrw(env, csrno, ret_value, new_value, write_mask);
1152 #if !defined(CONFIG_USER_ONLY)
1153     env->debugger = false;
1154 #endif
1155     return ret;
1156 }
1157 
1158 /* Control and Status Register function table */
1159 static riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
1160     /* User Floating-Point CSRs */
1161     [CSR_FFLAGS] =              { fs,   read_fflags,      write_fflags      },
1162     [CSR_FRM] =                 { fs,   read_frm,         write_frm         },
1163     [CSR_FCSR] =                { fs,   read_fcsr,        write_fcsr        },
1164 
1165     /* User Timers and Counters */
1166     [CSR_CYCLE] =               { ctr,  read_instret                        },
1167     [CSR_INSTRET] =             { ctr,  read_instret                        },
1168 #if defined(TARGET_RISCV32)
1169     [CSR_CYCLEH] =              { ctr,  read_instreth                       },
1170     [CSR_INSTRETH] =            { ctr,  read_instreth                       },
1171 #endif
1172 
1173     /* User-level time CSRs are only available in linux-user
1174      * In privileged mode, the monitor emulates these CSRs */
1175 #if defined(CONFIG_USER_ONLY)
1176     [CSR_TIME] =                { ctr,  read_time                           },
1177 #if defined(TARGET_RISCV32)
1178     [CSR_TIMEH] =               { ctr,  read_timeh                          },
1179 #endif
1180 #endif
1181 
1182 #if !defined(CONFIG_USER_ONLY)
1183     /* Machine Timers and Counters */
1184     [CSR_MCYCLE] =              { any,  read_instret                        },
1185     [CSR_MINSTRET] =            { any,  read_instret                        },
1186 #if defined(TARGET_RISCV32)
1187     [CSR_MCYCLEH] =             { any,  read_instreth                       },
1188     [CSR_MINSTRETH] =           { any,  read_instreth                       },
1189 #endif
1190 
1191     /* Machine Information Registers */
1192     [CSR_MVENDORID] =           { any,  read_zero                           },
1193     [CSR_MARCHID] =             { any,  read_zero                           },
1194     [CSR_MIMPID] =              { any,  read_zero                           },
1195     [CSR_MHARTID] =             { any,  read_mhartid                        },
1196 
1197     /* Machine Trap Setup */
1198     [CSR_MSTATUS] =             { any,  read_mstatus,     write_mstatus     },
1199     [CSR_MISA] =                { any,  read_misa,        write_misa        },
1200     [CSR_MIDELEG] =             { any,  read_mideleg,     write_mideleg     },
1201     [CSR_MEDELEG] =             { any,  read_medeleg,     write_medeleg     },
1202     [CSR_MIE] =                 { any,  read_mie,         write_mie         },
1203     [CSR_MTVEC] =               { any,  read_mtvec,       write_mtvec       },
1204     [CSR_MCOUNTEREN] =          { any,  read_mcounteren,  write_mcounteren  },
1205 
1206     /* Legacy Counter Setup (priv v1.9.1) */
1207     [CSR_MUCOUNTEREN] =         { any,  read_mucounteren, write_mucounteren },
1208     [CSR_MSCOUNTEREN] =         { any,  read_mscounteren, write_mscounteren },
1209 
1210     /* Machine Trap Handling */
1211     [CSR_MSCRATCH] =            { any,  read_mscratch,    write_mscratch    },
1212     [CSR_MEPC] =                { any,  read_mepc,        write_mepc        },
1213     [CSR_MCAUSE] =              { any,  read_mcause,      write_mcause      },
1214     [CSR_MBADADDR] =            { any,  read_mbadaddr,    write_mbadaddr    },
1215     [CSR_MIP] =                 { any,  NULL,     NULL,     rmw_mip         },
1216 
1217     /* Supervisor Trap Setup */
1218     [CSR_SSTATUS] =             { smode, read_sstatus,     write_sstatus     },
1219     [CSR_SIE] =                 { smode, read_sie,         write_sie         },
1220     [CSR_STVEC] =               { smode, read_stvec,       write_stvec       },
1221     [CSR_SCOUNTEREN] =          { smode, read_scounteren,  write_scounteren  },
1222 
1223     /* Supervisor Trap Handling */
1224     [CSR_SSCRATCH] =            { smode, read_sscratch,    write_sscratch    },
1225     [CSR_SEPC] =                { smode, read_sepc,        write_sepc        },
1226     [CSR_SCAUSE] =              { smode, read_scause,      write_scause      },
1227     [CSR_SBADADDR] =            { smode, read_sbadaddr,    write_sbadaddr    },
1228     [CSR_SIP] =                 { smode, NULL,     NULL,     rmw_sip         },
1229 
1230     /* Supervisor Protection and Translation */
1231     [CSR_SATP] =                { smode, read_satp,        write_satp        },
1232 
1233     [CSR_HSTATUS] =             { hmode,   read_hstatus,     write_hstatus    },
1234     [CSR_HEDELEG] =             { hmode,   read_hedeleg,     write_hedeleg    },
1235     [CSR_HIDELEG] =             { hmode,   read_hideleg,     write_hideleg    },
1236     [CSR_HIP] =                 { hmode,   NULL,     NULL,     rmw_hip        },
1237     [CSR_HIE] =                 { hmode,   read_hie,         write_hie        },
1238     [CSR_HCOUNTEREN] =          { hmode,   read_hcounteren,  write_hcounteren },
1239     [CSR_HTVAL] =               { hmode,   read_htval,       write_htval      },
1240     [CSR_HTINST] =              { hmode,   read_htinst,      write_htinst     },
1241     [CSR_HGATP] =               { hmode,   read_hgatp,       write_hgatp      },
1242 
1243     [CSR_VSSTATUS] =            { hmode,   read_vsstatus,    write_vsstatus   },
1244     [CSR_VSIP] =                { hmode,   NULL,     NULL,     rmw_vsip       },
1245     [CSR_VSIE] =                { hmode,   read_vsie,        write_vsie       },
1246     [CSR_VSTVEC] =              { hmode,   read_vstvec,      write_vstvec     },
1247     [CSR_VSSCRATCH] =           { hmode,   read_vsscratch,   write_vsscratch  },
1248     [CSR_VSEPC] =               { hmode,   read_vsepc,       write_vsepc      },
1249     [CSR_VSCAUSE] =             { hmode,   read_vscause,     write_vscause    },
1250     [CSR_VSTVAL] =              { hmode,   read_vstval,      write_vstval     },
1251     [CSR_VSATP] =               { hmode,   read_vsatp,       write_vsatp      },
1252 
1253     [CSR_MTVAL2] =              { hmode,   read_mtval2,      write_mtval2     },
1254     [CSR_MTINST] =              { hmode,   read_mtinst,      write_mtinst     },
1255 
1256     /* Physical Memory Protection */
1257     [CSR_PMPCFG0  ... CSR_PMPADDR9] =  { pmp,   read_pmpcfg,  write_pmpcfg   },
1258     [CSR_PMPADDR0 ... CSR_PMPADDR15] = { pmp,   read_pmpaddr, write_pmpaddr  },
1259 
1260     /* Performance Counters */
1261     [CSR_HPMCOUNTER3   ... CSR_HPMCOUNTER31] =    { ctr,  read_zero          },
1262     [CSR_MHPMCOUNTER3  ... CSR_MHPMCOUNTER31] =   { any,  read_zero          },
1263     [CSR_MHPMEVENT3    ... CSR_MHPMEVENT31] =     { any,  read_zero          },
1264 #if defined(TARGET_RISCV32)
1265     [CSR_HPMCOUNTER3H  ... CSR_HPMCOUNTER31H] =   { ctr,  read_zero          },
1266     [CSR_MHPMCOUNTER3H ... CSR_MHPMCOUNTER31H] =  { any,  read_zero          },
1267 #endif
1268 #endif /* !CONFIG_USER_ONLY */
1269 };
1270