xref: /openbmc/qemu/target/riscv/csr.c (revision a2e9f57d)
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;
747 
748     if (riscv_cpu_virt_enabled(env)) {
749         /* Shift the new values to line up with the VS bits */
750         ret = rmw_mip(env, CSR_MSTATUS, ret_value, new_value << 1,
751                       (write_mask & sip_writable_mask) << 1 & env->mideleg);
752         ret &= vsip_writable_mask;
753         ret >>= 1;
754     } else {
755         ret = rmw_mip(env, CSR_MSTATUS, ret_value, new_value,
756                       write_mask & env->mideleg & sip_writable_mask);
757     }
758 
759     *ret_value &= env->mideleg;
760     return ret;
761 }
762 
763 /* Supervisor Protection and Translation */
764 static int read_satp(CPURISCVState *env, int csrno, target_ulong *val)
765 {
766     if (!riscv_feature(env, RISCV_FEATURE_MMU)) {
767         *val = 0;
768     } else if (env->priv_ver >= PRIV_VERSION_1_10_0) {
769         if (env->priv == PRV_S && get_field(env->mstatus, MSTATUS_TVM)) {
770             return -1;
771         } else {
772             *val = env->satp;
773         }
774     } else {
775         *val = env->sptbr;
776     }
777     return 0;
778 }
779 
780 static int write_satp(CPURISCVState *env, int csrno, target_ulong val)
781 {
782     if (!riscv_feature(env, RISCV_FEATURE_MMU)) {
783         return 0;
784     }
785     if (env->priv_ver <= PRIV_VERSION_1_09_1 && (val ^ env->sptbr)) {
786         tlb_flush(env_cpu(env));
787         env->sptbr = val & (((target_ulong)
788             1 << (TARGET_PHYS_ADDR_SPACE_BITS - PGSHIFT)) - 1);
789     }
790     if (env->priv_ver >= PRIV_VERSION_1_10_0 &&
791         validate_vm(env, get_field(val, SATP_MODE)) &&
792         ((val ^ env->satp) & (SATP_MODE | SATP_ASID | SATP_PPN)))
793     {
794         if (env->priv == PRV_S && get_field(env->mstatus, MSTATUS_TVM)) {
795             return -1;
796         } else {
797             if((val ^ env->satp) & SATP_ASID) {
798                 tlb_flush(env_cpu(env));
799             }
800             env->satp = val;
801         }
802     }
803     return 0;
804 }
805 
806 /* Hypervisor Extensions */
807 static int read_hstatus(CPURISCVState *env, int csrno, target_ulong *val)
808 {
809     *val = env->hstatus;
810     return 0;
811 }
812 
813 static int write_hstatus(CPURISCVState *env, int csrno, target_ulong val)
814 {
815     env->hstatus = val;
816     return 0;
817 }
818 
819 static int read_hedeleg(CPURISCVState *env, int csrno, target_ulong *val)
820 {
821     *val = env->hedeleg;
822     return 0;
823 }
824 
825 static int write_hedeleg(CPURISCVState *env, int csrno, target_ulong val)
826 {
827     env->hedeleg = val;
828     return 0;
829 }
830 
831 static int read_hideleg(CPURISCVState *env, int csrno, target_ulong *val)
832 {
833     *val = env->hideleg;
834     return 0;
835 }
836 
837 static int write_hideleg(CPURISCVState *env, int csrno, target_ulong val)
838 {
839     env->hideleg = val;
840     return 0;
841 }
842 
843 static int rmw_hip(CPURISCVState *env, int csrno, target_ulong *ret_value,
844                    target_ulong new_value, target_ulong write_mask)
845 {
846     int ret = rmw_mip(env, 0, ret_value, new_value,
847                       write_mask & hip_writable_mask);
848 
849     return ret;
850 }
851 
852 static int read_hie(CPURISCVState *env, int csrno, target_ulong *val)
853 {
854     *val = env->mie & VS_MODE_INTERRUPTS;
855     return 0;
856 }
857 
858 static int write_hie(CPURISCVState *env, int csrno, target_ulong val)
859 {
860     target_ulong newval = (env->mie & ~VS_MODE_INTERRUPTS) | (val & VS_MODE_INTERRUPTS);
861     return write_mie(env, CSR_MIE, newval);
862 }
863 
864 static int read_hcounteren(CPURISCVState *env, int csrno, target_ulong *val)
865 {
866     *val = env->hcounteren;
867     return 0;
868 }
869 
870 static int write_hcounteren(CPURISCVState *env, int csrno, target_ulong val)
871 {
872     env->hcounteren = val;
873     return 0;
874 }
875 
876 static int read_htval(CPURISCVState *env, int csrno, target_ulong *val)
877 {
878     *val = env->htval;
879     return 0;
880 }
881 
882 static int write_htval(CPURISCVState *env, int csrno, target_ulong val)
883 {
884     env->htval = val;
885     return 0;
886 }
887 
888 static int read_htinst(CPURISCVState *env, int csrno, target_ulong *val)
889 {
890     *val = env->htinst;
891     return 0;
892 }
893 
894 static int write_htinst(CPURISCVState *env, int csrno, target_ulong val)
895 {
896     env->htinst = val;
897     return 0;
898 }
899 
900 static int read_hgatp(CPURISCVState *env, int csrno, target_ulong *val)
901 {
902     *val = env->hgatp;
903     return 0;
904 }
905 
906 static int write_hgatp(CPURISCVState *env, int csrno, target_ulong val)
907 {
908     env->hgatp = val;
909     return 0;
910 }
911 
912 /* Virtual CSR Registers */
913 static int read_vsstatus(CPURISCVState *env, int csrno, target_ulong *val)
914 {
915     *val = env->vsstatus;
916     return 0;
917 }
918 
919 static int write_vsstatus(CPURISCVState *env, int csrno, target_ulong val)
920 {
921     env->vsstatus = val;
922     return 0;
923 }
924 
925 static int rmw_vsip(CPURISCVState *env, int csrno, target_ulong *ret_value,
926                     target_ulong new_value, target_ulong write_mask)
927 {
928     int ret = rmw_mip(env, 0, ret_value, new_value,
929                       write_mask & env->mideleg & vsip_writable_mask);
930     return ret;
931 }
932 
933 static int read_vsie(CPURISCVState *env, int csrno, target_ulong *val)
934 {
935     *val = env->mie & env->mideleg & VS_MODE_INTERRUPTS;
936     return 0;
937 }
938 
939 static int write_vsie(CPURISCVState *env, int csrno, target_ulong val)
940 {
941     target_ulong newval = (env->mie & ~env->mideleg) | (val & env->mideleg & MIP_VSSIP);
942     return write_mie(env, CSR_MIE, newval);
943 }
944 
945 static int read_vstvec(CPURISCVState *env, int csrno, target_ulong *val)
946 {
947     *val = env->vstvec;
948     return 0;
949 }
950 
951 static int write_vstvec(CPURISCVState *env, int csrno, target_ulong val)
952 {
953     env->vstvec = val;
954     return 0;
955 }
956 
957 static int read_vsscratch(CPURISCVState *env, int csrno, target_ulong *val)
958 {
959     *val = env->vsscratch;
960     return 0;
961 }
962 
963 static int write_vsscratch(CPURISCVState *env, int csrno, target_ulong val)
964 {
965     env->vsscratch = val;
966     return 0;
967 }
968 
969 static int read_vsepc(CPURISCVState *env, int csrno, target_ulong *val)
970 {
971     *val = env->vsepc;
972     return 0;
973 }
974 
975 static int write_vsepc(CPURISCVState *env, int csrno, target_ulong val)
976 {
977     env->vsepc = val;
978     return 0;
979 }
980 
981 static int read_vscause(CPURISCVState *env, int csrno, target_ulong *val)
982 {
983     *val = env->vscause;
984     return 0;
985 }
986 
987 static int write_vscause(CPURISCVState *env, int csrno, target_ulong val)
988 {
989     env->vscause = val;
990     return 0;
991 }
992 
993 static int read_vstval(CPURISCVState *env, int csrno, target_ulong *val)
994 {
995     *val = env->vstval;
996     return 0;
997 }
998 
999 static int write_vstval(CPURISCVState *env, int csrno, target_ulong val)
1000 {
1001     env->vstval = val;
1002     return 0;
1003 }
1004 
1005 static int read_vsatp(CPURISCVState *env, int csrno, target_ulong *val)
1006 {
1007     *val = env->vsatp;
1008     return 0;
1009 }
1010 
1011 static int write_vsatp(CPURISCVState *env, int csrno, target_ulong val)
1012 {
1013     env->vsatp = val;
1014     return 0;
1015 }
1016 
1017 static int read_mtval2(CPURISCVState *env, int csrno, target_ulong *val)
1018 {
1019     *val = env->mtval2;
1020     return 0;
1021 }
1022 
1023 static int write_mtval2(CPURISCVState *env, int csrno, target_ulong val)
1024 {
1025     env->mtval2 = val;
1026     return 0;
1027 }
1028 
1029 static int read_mtinst(CPURISCVState *env, int csrno, target_ulong *val)
1030 {
1031     *val = env->mtinst;
1032     return 0;
1033 }
1034 
1035 static int write_mtinst(CPURISCVState *env, int csrno, target_ulong val)
1036 {
1037     env->mtinst = val;
1038     return 0;
1039 }
1040 
1041 /* Physical Memory Protection */
1042 static int read_pmpcfg(CPURISCVState *env, int csrno, target_ulong *val)
1043 {
1044     *val = pmpcfg_csr_read(env, csrno - CSR_PMPCFG0);
1045     return 0;
1046 }
1047 
1048 static int write_pmpcfg(CPURISCVState *env, int csrno, target_ulong val)
1049 {
1050     pmpcfg_csr_write(env, csrno - CSR_PMPCFG0, val);
1051     return 0;
1052 }
1053 
1054 static int read_pmpaddr(CPURISCVState *env, int csrno, target_ulong *val)
1055 {
1056     *val = pmpaddr_csr_read(env, csrno - CSR_PMPADDR0);
1057     return 0;
1058 }
1059 
1060 static int write_pmpaddr(CPURISCVState *env, int csrno, target_ulong val)
1061 {
1062     pmpaddr_csr_write(env, csrno - CSR_PMPADDR0, val);
1063     return 0;
1064 }
1065 
1066 #endif
1067 
1068 /*
1069  * riscv_csrrw - read and/or update control and status register
1070  *
1071  * csrr   <->  riscv_csrrw(env, csrno, ret_value, 0, 0);
1072  * csrrw  <->  riscv_csrrw(env, csrno, ret_value, value, -1);
1073  * csrrs  <->  riscv_csrrw(env, csrno, ret_value, -1, value);
1074  * csrrc  <->  riscv_csrrw(env, csrno, ret_value, 0, value);
1075  */
1076 
1077 int riscv_csrrw(CPURISCVState *env, int csrno, target_ulong *ret_value,
1078                 target_ulong new_value, target_ulong write_mask)
1079 {
1080     int ret;
1081     target_ulong old_value;
1082     RISCVCPU *cpu = env_archcpu(env);
1083 
1084     /* check privileges and return -1 if check fails */
1085 #if !defined(CONFIG_USER_ONLY)
1086     int effective_priv = env->priv;
1087     int read_only = get_field(csrno, 0xC00) == 3;
1088 
1089     if (riscv_has_ext(env, RVH) &&
1090         env->priv == PRV_S &&
1091         !riscv_cpu_virt_enabled(env)) {
1092         /*
1093          * We are in S mode without virtualisation, therefore we are in HS Mode.
1094          * Add 1 to the effective privledge level to allow us to access the
1095          * Hypervisor CSRs.
1096          */
1097         effective_priv++;
1098     }
1099 
1100     if ((write_mask && read_only) ||
1101         (!env->debugger && (effective_priv < get_field(csrno, 0x300)))) {
1102         return -1;
1103     }
1104 #endif
1105 
1106     /* ensure the CSR extension is enabled. */
1107     if (!cpu->cfg.ext_icsr) {
1108         return -1;
1109     }
1110 
1111     /* check predicate */
1112     if (!csr_ops[csrno].predicate || csr_ops[csrno].predicate(env, csrno) < 0) {
1113         return -1;
1114     }
1115 
1116     /* execute combined read/write operation if it exists */
1117     if (csr_ops[csrno].op) {
1118         return csr_ops[csrno].op(env, csrno, ret_value, new_value, write_mask);
1119     }
1120 
1121     /* if no accessor exists then return failure */
1122     if (!csr_ops[csrno].read) {
1123         return -1;
1124     }
1125 
1126     /* read old value */
1127     ret = csr_ops[csrno].read(env, csrno, &old_value);
1128     if (ret < 0) {
1129         return ret;
1130     }
1131 
1132     /* write value if writable and write mask set, otherwise drop writes */
1133     if (write_mask) {
1134         new_value = (old_value & ~write_mask) | (new_value & write_mask);
1135         if (csr_ops[csrno].write) {
1136             ret = csr_ops[csrno].write(env, csrno, new_value);
1137             if (ret < 0) {
1138                 return ret;
1139             }
1140         }
1141     }
1142 
1143     /* return old value */
1144     if (ret_value) {
1145         *ret_value = old_value;
1146     }
1147 
1148     return 0;
1149 }
1150 
1151 /*
1152  * Debugger support.  If not in user mode, set env->debugger before the
1153  * riscv_csrrw call and clear it after the call.
1154  */
1155 int riscv_csrrw_debug(CPURISCVState *env, int csrno, target_ulong *ret_value,
1156                 target_ulong new_value, target_ulong write_mask)
1157 {
1158     int ret;
1159 #if !defined(CONFIG_USER_ONLY)
1160     env->debugger = true;
1161 #endif
1162     ret = riscv_csrrw(env, csrno, ret_value, new_value, write_mask);
1163 #if !defined(CONFIG_USER_ONLY)
1164     env->debugger = false;
1165 #endif
1166     return ret;
1167 }
1168 
1169 /* Control and Status Register function table */
1170 static riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
1171     /* User Floating-Point CSRs */
1172     [CSR_FFLAGS] =              { fs,   read_fflags,      write_fflags      },
1173     [CSR_FRM] =                 { fs,   read_frm,         write_frm         },
1174     [CSR_FCSR] =                { fs,   read_fcsr,        write_fcsr        },
1175 
1176     /* User Timers and Counters */
1177     [CSR_CYCLE] =               { ctr,  read_instret                        },
1178     [CSR_INSTRET] =             { ctr,  read_instret                        },
1179 #if defined(TARGET_RISCV32)
1180     [CSR_CYCLEH] =              { ctr,  read_instreth                       },
1181     [CSR_INSTRETH] =            { ctr,  read_instreth                       },
1182 #endif
1183 
1184     /* User-level time CSRs are only available in linux-user
1185      * In privileged mode, the monitor emulates these CSRs */
1186 #if defined(CONFIG_USER_ONLY)
1187     [CSR_TIME] =                { ctr,  read_time                           },
1188 #if defined(TARGET_RISCV32)
1189     [CSR_TIMEH] =               { ctr,  read_timeh                          },
1190 #endif
1191 #endif
1192 
1193 #if !defined(CONFIG_USER_ONLY)
1194     /* Machine Timers and Counters */
1195     [CSR_MCYCLE] =              { any,  read_instret                        },
1196     [CSR_MINSTRET] =            { any,  read_instret                        },
1197 #if defined(TARGET_RISCV32)
1198     [CSR_MCYCLEH] =             { any,  read_instreth                       },
1199     [CSR_MINSTRETH] =           { any,  read_instreth                       },
1200 #endif
1201 
1202     /* Machine Information Registers */
1203     [CSR_MVENDORID] =           { any,  read_zero                           },
1204     [CSR_MARCHID] =             { any,  read_zero                           },
1205     [CSR_MIMPID] =              { any,  read_zero                           },
1206     [CSR_MHARTID] =             { any,  read_mhartid                        },
1207 
1208     /* Machine Trap Setup */
1209     [CSR_MSTATUS] =             { any,  read_mstatus,     write_mstatus     },
1210     [CSR_MISA] =                { any,  read_misa,        write_misa        },
1211     [CSR_MIDELEG] =             { any,  read_mideleg,     write_mideleg     },
1212     [CSR_MEDELEG] =             { any,  read_medeleg,     write_medeleg     },
1213     [CSR_MIE] =                 { any,  read_mie,         write_mie         },
1214     [CSR_MTVEC] =               { any,  read_mtvec,       write_mtvec       },
1215     [CSR_MCOUNTEREN] =          { any,  read_mcounteren,  write_mcounteren  },
1216 
1217     /* Legacy Counter Setup (priv v1.9.1) */
1218     [CSR_MUCOUNTEREN] =         { any,  read_mucounteren, write_mucounteren },
1219     [CSR_MSCOUNTEREN] =         { any,  read_mscounteren, write_mscounteren },
1220 
1221     /* Machine Trap Handling */
1222     [CSR_MSCRATCH] =            { any,  read_mscratch,    write_mscratch    },
1223     [CSR_MEPC] =                { any,  read_mepc,        write_mepc        },
1224     [CSR_MCAUSE] =              { any,  read_mcause,      write_mcause      },
1225     [CSR_MBADADDR] =            { any,  read_mbadaddr,    write_mbadaddr    },
1226     [CSR_MIP] =                 { any,  NULL,     NULL,     rmw_mip         },
1227 
1228     /* Supervisor Trap Setup */
1229     [CSR_SSTATUS] =             { smode, read_sstatus,     write_sstatus     },
1230     [CSR_SIE] =                 { smode, read_sie,         write_sie         },
1231     [CSR_STVEC] =               { smode, read_stvec,       write_stvec       },
1232     [CSR_SCOUNTEREN] =          { smode, read_scounteren,  write_scounteren  },
1233 
1234     /* Supervisor Trap Handling */
1235     [CSR_SSCRATCH] =            { smode, read_sscratch,    write_sscratch    },
1236     [CSR_SEPC] =                { smode, read_sepc,        write_sepc        },
1237     [CSR_SCAUSE] =              { smode, read_scause,      write_scause      },
1238     [CSR_SBADADDR] =            { smode, read_sbadaddr,    write_sbadaddr    },
1239     [CSR_SIP] =                 { smode, NULL,     NULL,     rmw_sip         },
1240 
1241     /* Supervisor Protection and Translation */
1242     [CSR_SATP] =                { smode, read_satp,        write_satp        },
1243 
1244     [CSR_HSTATUS] =             { hmode,   read_hstatus,     write_hstatus    },
1245     [CSR_HEDELEG] =             { hmode,   read_hedeleg,     write_hedeleg    },
1246     [CSR_HIDELEG] =             { hmode,   read_hideleg,     write_hideleg    },
1247     [CSR_HIP] =                 { hmode,   NULL,     NULL,     rmw_hip        },
1248     [CSR_HIE] =                 { hmode,   read_hie,         write_hie        },
1249     [CSR_HCOUNTEREN] =          { hmode,   read_hcounteren,  write_hcounteren },
1250     [CSR_HTVAL] =               { hmode,   read_htval,       write_htval      },
1251     [CSR_HTINST] =              { hmode,   read_htinst,      write_htinst     },
1252     [CSR_HGATP] =               { hmode,   read_hgatp,       write_hgatp      },
1253 
1254     [CSR_VSSTATUS] =            { hmode,   read_vsstatus,    write_vsstatus   },
1255     [CSR_VSIP] =                { hmode,   NULL,     NULL,     rmw_vsip       },
1256     [CSR_VSIE] =                { hmode,   read_vsie,        write_vsie       },
1257     [CSR_VSTVEC] =              { hmode,   read_vstvec,      write_vstvec     },
1258     [CSR_VSSCRATCH] =           { hmode,   read_vsscratch,   write_vsscratch  },
1259     [CSR_VSEPC] =               { hmode,   read_vsepc,       write_vsepc      },
1260     [CSR_VSCAUSE] =             { hmode,   read_vscause,     write_vscause    },
1261     [CSR_VSTVAL] =              { hmode,   read_vstval,      write_vstval     },
1262     [CSR_VSATP] =               { hmode,   read_vsatp,       write_vsatp      },
1263 
1264     [CSR_MTVAL2] =              { hmode,   read_mtval2,      write_mtval2     },
1265     [CSR_MTINST] =              { hmode,   read_mtinst,      write_mtinst     },
1266 
1267     /* Physical Memory Protection */
1268     [CSR_PMPCFG0  ... CSR_PMPADDR9] =  { pmp,   read_pmpcfg,  write_pmpcfg   },
1269     [CSR_PMPADDR0 ... CSR_PMPADDR15] = { pmp,   read_pmpaddr, write_pmpaddr  },
1270 
1271     /* Performance Counters */
1272     [CSR_HPMCOUNTER3   ... CSR_HPMCOUNTER31] =    { ctr,  read_zero          },
1273     [CSR_MHPMCOUNTER3  ... CSR_MHPMCOUNTER31] =   { any,  read_zero          },
1274     [CSR_MHPMEVENT3    ... CSR_MHPMEVENT31] =     { any,  read_zero          },
1275 #if defined(TARGET_RISCV32)
1276     [CSR_HPMCOUNTER3H  ... CSR_HPMCOUNTER31H] =   { ctr,  read_zero          },
1277     [CSR_MHPMCOUNTER3H ... CSR_MHPMCOUNTER31H] =  { any,  read_zero          },
1278 #endif
1279 #endif /* !CONFIG_USER_ONLY */
1280 };
1281