xref: /openbmc/qemu/target/riscv/csr.c (revision 2a886794)
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 pmp(CPURISCVState *env, int csrno)
102 {
103     return -!riscv_feature(env, RISCV_FEATURE_PMP);
104 }
105 #endif
106 
107 /* User Floating-Point CSRs */
108 static int read_fflags(CPURISCVState *env, int csrno, target_ulong *val)
109 {
110 #if !defined(CONFIG_USER_ONLY)
111     if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
112         return -1;
113     }
114 #endif
115     *val = riscv_cpu_get_fflags(env);
116     return 0;
117 }
118 
119 static int write_fflags(CPURISCVState *env, int csrno, target_ulong val)
120 {
121 #if !defined(CONFIG_USER_ONLY)
122     if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
123         return -1;
124     }
125     env->mstatus |= MSTATUS_FS;
126 #endif
127     riscv_cpu_set_fflags(env, val & (FSR_AEXC >> FSR_AEXC_SHIFT));
128     return 0;
129 }
130 
131 static int read_frm(CPURISCVState *env, int csrno, target_ulong *val)
132 {
133 #if !defined(CONFIG_USER_ONLY)
134     if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
135         return -1;
136     }
137 #endif
138     *val = env->frm;
139     return 0;
140 }
141 
142 static int write_frm(CPURISCVState *env, int csrno, target_ulong val)
143 {
144 #if !defined(CONFIG_USER_ONLY)
145     if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
146         return -1;
147     }
148     env->mstatus |= MSTATUS_FS;
149 #endif
150     env->frm = val & (FSR_RD >> FSR_RD_SHIFT);
151     return 0;
152 }
153 
154 static int read_fcsr(CPURISCVState *env, int csrno, target_ulong *val)
155 {
156 #if !defined(CONFIG_USER_ONLY)
157     if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
158         return -1;
159     }
160 #endif
161     *val = (riscv_cpu_get_fflags(env) << FSR_AEXC_SHIFT)
162         | (env->frm << FSR_RD_SHIFT);
163     return 0;
164 }
165 
166 static int write_fcsr(CPURISCVState *env, int csrno, target_ulong val)
167 {
168 #if !defined(CONFIG_USER_ONLY)
169     if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
170         return -1;
171     }
172     env->mstatus |= MSTATUS_FS;
173 #endif
174     env->frm = (val & FSR_RD) >> FSR_RD_SHIFT;
175     riscv_cpu_set_fflags(env, (val & FSR_AEXC) >> FSR_AEXC_SHIFT);
176     return 0;
177 }
178 
179 /* User Timers and Counters */
180 static int read_instret(CPURISCVState *env, int csrno, target_ulong *val)
181 {
182 #if !defined(CONFIG_USER_ONLY)
183     if (use_icount) {
184         *val = cpu_get_icount();
185     } else {
186         *val = cpu_get_host_ticks();
187     }
188 #else
189     *val = cpu_get_host_ticks();
190 #endif
191     return 0;
192 }
193 
194 #if defined(TARGET_RISCV32)
195 static int read_instreth(CPURISCVState *env, int csrno, target_ulong *val)
196 {
197 #if !defined(CONFIG_USER_ONLY)
198     if (use_icount) {
199         *val = cpu_get_icount() >> 32;
200     } else {
201         *val = cpu_get_host_ticks() >> 32;
202     }
203 #else
204     *val = cpu_get_host_ticks() >> 32;
205 #endif
206     return 0;
207 }
208 #endif /* TARGET_RISCV32 */
209 
210 #if defined(CONFIG_USER_ONLY)
211 static int read_time(CPURISCVState *env, int csrno, target_ulong *val)
212 {
213     *val = cpu_get_host_ticks();
214     return 0;
215 }
216 
217 #if defined(TARGET_RISCV32)
218 static int read_timeh(CPURISCVState *env, int csrno, target_ulong *val)
219 {
220     *val = cpu_get_host_ticks() >> 32;
221     return 0;
222 }
223 #endif
224 
225 #else /* CONFIG_USER_ONLY */
226 
227 /* Machine constants */
228 
229 #define M_MODE_INTERRUPTS (MIP_MSIP | MIP_MTIP | MIP_MEIP)
230 #define S_MODE_INTERRUPTS (MIP_SSIP | MIP_STIP | MIP_SEIP)
231 
232 static const target_ulong delegable_ints = S_MODE_INTERRUPTS;
233 static const target_ulong all_ints = M_MODE_INTERRUPTS | S_MODE_INTERRUPTS;
234 static const target_ulong delegable_excps =
235     (1ULL << (RISCV_EXCP_INST_ADDR_MIS)) |
236     (1ULL << (RISCV_EXCP_INST_ACCESS_FAULT)) |
237     (1ULL << (RISCV_EXCP_ILLEGAL_INST)) |
238     (1ULL << (RISCV_EXCP_BREAKPOINT)) |
239     (1ULL << (RISCV_EXCP_LOAD_ADDR_MIS)) |
240     (1ULL << (RISCV_EXCP_LOAD_ACCESS_FAULT)) |
241     (1ULL << (RISCV_EXCP_STORE_AMO_ADDR_MIS)) |
242     (1ULL << (RISCV_EXCP_STORE_AMO_ACCESS_FAULT)) |
243     (1ULL << (RISCV_EXCP_U_ECALL)) |
244     (1ULL << (RISCV_EXCP_S_ECALL)) |
245     (1ULL << (RISCV_EXCP_H_ECALL)) |
246     (1ULL << (RISCV_EXCP_M_ECALL)) |
247     (1ULL << (RISCV_EXCP_INST_PAGE_FAULT)) |
248     (1ULL << (RISCV_EXCP_LOAD_PAGE_FAULT)) |
249     (1ULL << (RISCV_EXCP_STORE_PAGE_FAULT));
250 static const target_ulong sstatus_v1_9_mask = SSTATUS_SIE | SSTATUS_SPIE |
251     SSTATUS_UIE | SSTATUS_UPIE | SSTATUS_SPP | SSTATUS_FS | SSTATUS_XS |
252     SSTATUS_SUM | SSTATUS_SD;
253 static const target_ulong sstatus_v1_10_mask = SSTATUS_SIE | SSTATUS_SPIE |
254     SSTATUS_UIE | SSTATUS_UPIE | SSTATUS_SPP | SSTATUS_FS | SSTATUS_XS |
255     SSTATUS_SUM | SSTATUS_MXR | SSTATUS_SD;
256 static const target_ulong sip_writable_mask = SIP_SSIP | MIP_USIP | MIP_UEIP;
257 
258 #if defined(TARGET_RISCV32)
259 static const char valid_vm_1_09[16] = {
260     [VM_1_09_MBARE] = 1,
261     [VM_1_09_SV32] = 1,
262 };
263 static const char valid_vm_1_10[16] = {
264     [VM_1_10_MBARE] = 1,
265     [VM_1_10_SV32] = 1
266 };
267 #elif defined(TARGET_RISCV64)
268 static const char valid_vm_1_09[16] = {
269     [VM_1_09_MBARE] = 1,
270     [VM_1_09_SV39] = 1,
271     [VM_1_09_SV48] = 1,
272 };
273 static const char valid_vm_1_10[16] = {
274     [VM_1_10_MBARE] = 1,
275     [VM_1_10_SV39] = 1,
276     [VM_1_10_SV48] = 1,
277     [VM_1_10_SV57] = 1
278 };
279 #endif /* CONFIG_USER_ONLY */
280 
281 /* Machine Information Registers */
282 static int read_zero(CPURISCVState *env, int csrno, target_ulong *val)
283 {
284     return *val = 0;
285 }
286 
287 static int read_mhartid(CPURISCVState *env, int csrno, target_ulong *val)
288 {
289     *val = env->mhartid;
290     return 0;
291 }
292 
293 /* Machine Trap Setup */
294 static int read_mstatus(CPURISCVState *env, int csrno, target_ulong *val)
295 {
296     *val = env->mstatus;
297     return 0;
298 }
299 
300 static int validate_vm(CPURISCVState *env, target_ulong vm)
301 {
302     return (env->priv_ver >= PRIV_VERSION_1_10_0) ?
303         valid_vm_1_10[vm & 0xf] : valid_vm_1_09[vm & 0xf];
304 }
305 
306 static int write_mstatus(CPURISCVState *env, int csrno, target_ulong val)
307 {
308     target_ulong mstatus = env->mstatus;
309     target_ulong mask = 0;
310     int dirty;
311 
312     /* flush tlb on mstatus fields that affect VM */
313     if (env->priv_ver <= PRIV_VERSION_1_09_1) {
314         if ((val ^ mstatus) & (MSTATUS_MXR | MSTATUS_MPP |
315                 MSTATUS_MPRV | MSTATUS_SUM | MSTATUS_VM)) {
316             tlb_flush(env_cpu(env));
317         }
318         mask = MSTATUS_SIE | MSTATUS_SPIE | MSTATUS_MIE | MSTATUS_MPIE |
319             MSTATUS_SPP | MSTATUS_FS | MSTATUS_MPRV | MSTATUS_SUM |
320             MSTATUS_MPP | MSTATUS_MXR |
321             (validate_vm(env, get_field(val, MSTATUS_VM)) ?
322                 MSTATUS_VM : 0);
323     }
324     if (env->priv_ver >= PRIV_VERSION_1_10_0) {
325         if ((val ^ mstatus) & (MSTATUS_MXR | MSTATUS_MPP | MSTATUS_MPV |
326                 MSTATUS_MPRV | MSTATUS_SUM)) {
327             tlb_flush(env_cpu(env));
328         }
329         mask = MSTATUS_SIE | MSTATUS_SPIE | MSTATUS_MIE | MSTATUS_MPIE |
330             MSTATUS_SPP | MSTATUS_FS | MSTATUS_MPRV | MSTATUS_SUM |
331             MSTATUS_MPP | MSTATUS_MXR | MSTATUS_TVM | MSTATUS_TSR |
332             MSTATUS_TW;
333 #if defined(TARGET_RISCV64)
334             /*
335              * RV32: MPV and MTL are not in mstatus. The current plan is to
336              * add them to mstatush. For now, we just don't support it.
337              */
338             mask |= MSTATUS_MTL | MSTATUS_MPV;
339 #endif
340     }
341 
342     mstatus = (mstatus & ~mask) | (val & mask);
343 
344     dirty = (riscv_cpu_fp_enabled(env) &&
345              ((mstatus & MSTATUS_FS) == MSTATUS_FS)) |
346             ((mstatus & MSTATUS_XS) == MSTATUS_XS);
347     mstatus = set_field(mstatus, MSTATUS_SD, dirty);
348     env->mstatus = mstatus;
349 
350     return 0;
351 }
352 
353 static int read_misa(CPURISCVState *env, int csrno, target_ulong *val)
354 {
355     *val = env->misa;
356     return 0;
357 }
358 
359 static int write_misa(CPURISCVState *env, int csrno, target_ulong val)
360 {
361     if (!riscv_feature(env, RISCV_FEATURE_MISA)) {
362         /* drop write to misa */
363         return 0;
364     }
365 
366     /* 'I' or 'E' must be present */
367     if (!(val & (RVI | RVE))) {
368         /* It is not, drop write to misa */
369         return 0;
370     }
371 
372     /* 'E' excludes all other extensions */
373     if (val & RVE) {
374         /* when we support 'E' we can do "val = RVE;" however
375          * for now we just drop writes if 'E' is present.
376          */
377         return 0;
378     }
379 
380     /* Mask extensions that are not supported by this hart */
381     val &= env->misa_mask;
382 
383     /* Mask extensions that are not supported by QEMU */
384     val &= (RVI | RVE | RVM | RVA | RVF | RVD | RVC | RVS | RVU);
385 
386     /* 'D' depends on 'F', so clear 'D' if 'F' is not present */
387     if ((val & RVD) && !(val & RVF)) {
388         val &= ~RVD;
389     }
390 
391     /* Suppress 'C' if next instruction is not aligned
392      * TODO: this should check next_pc
393      */
394     if ((val & RVC) && (GETPC() & ~3) != 0) {
395         val &= ~RVC;
396     }
397 
398     /* misa.MXL writes are not supported by QEMU */
399     val = (env->misa & MISA_MXL) | (val & ~MISA_MXL);
400 
401     /* flush translation cache */
402     if (val != env->misa) {
403         tb_flush(env_cpu(env));
404     }
405 
406     env->misa = val;
407 
408     return 0;
409 }
410 
411 static int read_medeleg(CPURISCVState *env, int csrno, target_ulong *val)
412 {
413     *val = env->medeleg;
414     return 0;
415 }
416 
417 static int write_medeleg(CPURISCVState *env, int csrno, target_ulong val)
418 {
419     env->medeleg = (env->medeleg & ~delegable_excps) | (val & delegable_excps);
420     return 0;
421 }
422 
423 static int read_mideleg(CPURISCVState *env, int csrno, target_ulong *val)
424 {
425     *val = env->mideleg;
426     return 0;
427 }
428 
429 static int write_mideleg(CPURISCVState *env, int csrno, target_ulong val)
430 {
431     env->mideleg = (env->mideleg & ~delegable_ints) | (val & delegable_ints);
432     return 0;
433 }
434 
435 static int read_mie(CPURISCVState *env, int csrno, target_ulong *val)
436 {
437     *val = env->mie;
438     return 0;
439 }
440 
441 static int write_mie(CPURISCVState *env, int csrno, target_ulong val)
442 {
443     env->mie = (env->mie & ~all_ints) | (val & all_ints);
444     return 0;
445 }
446 
447 static int read_mtvec(CPURISCVState *env, int csrno, target_ulong *val)
448 {
449     *val = env->mtvec;
450     return 0;
451 }
452 
453 static int write_mtvec(CPURISCVState *env, int csrno, target_ulong val)
454 {
455     /* bits [1:0] encode mode; 0 = direct, 1 = vectored, 2 >= reserved */
456     if ((val & 3) < 2) {
457         env->mtvec = val;
458     } else {
459         qemu_log_mask(LOG_UNIMP, "CSR_MTVEC: reserved mode not supported\n");
460     }
461     return 0;
462 }
463 
464 static int read_mcounteren(CPURISCVState *env, int csrno, target_ulong *val)
465 {
466     if (env->priv_ver < PRIV_VERSION_1_10_0) {
467         return -1;
468     }
469     *val = env->mcounteren;
470     return 0;
471 }
472 
473 static int write_mcounteren(CPURISCVState *env, int csrno, target_ulong val)
474 {
475     if (env->priv_ver < PRIV_VERSION_1_10_0) {
476         return -1;
477     }
478     env->mcounteren = val;
479     return 0;
480 }
481 
482 /* This regiser is replaced with CSR_MCOUNTINHIBIT in 1.11.0 */
483 static int read_mscounteren(CPURISCVState *env, int csrno, target_ulong *val)
484 {
485     if (env->priv_ver > PRIV_VERSION_1_09_1
486         && env->priv_ver < PRIV_VERSION_1_11_0) {
487         return -1;
488     }
489     *val = env->mcounteren;
490     return 0;
491 }
492 
493 /* This regiser is replaced with CSR_MCOUNTINHIBIT in 1.11.0 */
494 static int write_mscounteren(CPURISCVState *env, int csrno, target_ulong val)
495 {
496     if (env->priv_ver > PRIV_VERSION_1_09_1
497         && env->priv_ver < PRIV_VERSION_1_11_0) {
498         return -1;
499     }
500     env->mcounteren = val;
501     return 0;
502 }
503 
504 static int read_mucounteren(CPURISCVState *env, int csrno, target_ulong *val)
505 {
506     if (env->priv_ver > PRIV_VERSION_1_09_1) {
507         return -1;
508     }
509     *val = env->scounteren;
510     return 0;
511 }
512 
513 static int write_mucounteren(CPURISCVState *env, int csrno, target_ulong val)
514 {
515     if (env->priv_ver > PRIV_VERSION_1_09_1) {
516         return -1;
517     }
518     env->scounteren = val;
519     return 0;
520 }
521 
522 /* Machine Trap Handling */
523 static int read_mscratch(CPURISCVState *env, int csrno, target_ulong *val)
524 {
525     *val = env->mscratch;
526     return 0;
527 }
528 
529 static int write_mscratch(CPURISCVState *env, int csrno, target_ulong val)
530 {
531     env->mscratch = val;
532     return 0;
533 }
534 
535 static int read_mepc(CPURISCVState *env, int csrno, target_ulong *val)
536 {
537     *val = env->mepc;
538     return 0;
539 }
540 
541 static int write_mepc(CPURISCVState *env, int csrno, target_ulong val)
542 {
543     env->mepc = val;
544     return 0;
545 }
546 
547 static int read_mcause(CPURISCVState *env, int csrno, target_ulong *val)
548 {
549     *val = env->mcause;
550     return 0;
551 }
552 
553 static int write_mcause(CPURISCVState *env, int csrno, target_ulong val)
554 {
555     env->mcause = val;
556     return 0;
557 }
558 
559 static int read_mbadaddr(CPURISCVState *env, int csrno, target_ulong *val)
560 {
561     *val = env->mbadaddr;
562     return 0;
563 }
564 
565 static int write_mbadaddr(CPURISCVState *env, int csrno, target_ulong val)
566 {
567     env->mbadaddr = val;
568     return 0;
569 }
570 
571 static int rmw_mip(CPURISCVState *env, int csrno, target_ulong *ret_value,
572                    target_ulong new_value, target_ulong write_mask)
573 {
574     RISCVCPU *cpu = env_archcpu(env);
575     /* Allow software control of delegable interrupts not claimed by hardware */
576     target_ulong mask = write_mask & delegable_ints & ~env->miclaim;
577     uint32_t old_mip;
578 
579     if (mask) {
580         old_mip = riscv_cpu_update_mip(cpu, mask, (new_value & mask));
581     } else {
582         old_mip = env->mip;
583     }
584 
585     if (ret_value) {
586         *ret_value = old_mip;
587     }
588 
589     return 0;
590 }
591 
592 /* Supervisor Trap Setup */
593 static int read_sstatus(CPURISCVState *env, int csrno, target_ulong *val)
594 {
595     target_ulong mask = ((env->priv_ver >= PRIV_VERSION_1_10_0) ?
596                          sstatus_v1_10_mask : sstatus_v1_9_mask);
597     *val = env->mstatus & mask;
598     return 0;
599 }
600 
601 static int write_sstatus(CPURISCVState *env, int csrno, target_ulong val)
602 {
603     target_ulong mask = ((env->priv_ver >= PRIV_VERSION_1_10_0) ?
604                          sstatus_v1_10_mask : sstatus_v1_9_mask);
605     target_ulong newval = (env->mstatus & ~mask) | (val & mask);
606     return write_mstatus(env, CSR_MSTATUS, newval);
607 }
608 
609 static int read_sie(CPURISCVState *env, int csrno, target_ulong *val)
610 {
611     *val = env->mie & env->mideleg;
612     return 0;
613 }
614 
615 static int write_sie(CPURISCVState *env, int csrno, target_ulong val)
616 {
617     target_ulong newval = (env->mie & ~env->mideleg) | (val & env->mideleg);
618     return write_mie(env, CSR_MIE, newval);
619 }
620 
621 static int read_stvec(CPURISCVState *env, int csrno, target_ulong *val)
622 {
623     *val = env->stvec;
624     return 0;
625 }
626 
627 static int write_stvec(CPURISCVState *env, int csrno, target_ulong val)
628 {
629     /* bits [1:0] encode mode; 0 = direct, 1 = vectored, 2 >= reserved */
630     if ((val & 3) < 2) {
631         env->stvec = val;
632     } else {
633         qemu_log_mask(LOG_UNIMP, "CSR_STVEC: reserved mode not supported\n");
634     }
635     return 0;
636 }
637 
638 static int read_scounteren(CPURISCVState *env, int csrno, target_ulong *val)
639 {
640     if (env->priv_ver < PRIV_VERSION_1_10_0) {
641         return -1;
642     }
643     *val = env->scounteren;
644     return 0;
645 }
646 
647 static int write_scounteren(CPURISCVState *env, int csrno, target_ulong val)
648 {
649     if (env->priv_ver < PRIV_VERSION_1_10_0) {
650         return -1;
651     }
652     env->scounteren = val;
653     return 0;
654 }
655 
656 /* Supervisor Trap Handling */
657 static int read_sscratch(CPURISCVState *env, int csrno, target_ulong *val)
658 {
659     *val = env->sscratch;
660     return 0;
661 }
662 
663 static int write_sscratch(CPURISCVState *env, int csrno, target_ulong val)
664 {
665     env->sscratch = val;
666     return 0;
667 }
668 
669 static int read_sepc(CPURISCVState *env, int csrno, target_ulong *val)
670 {
671     *val = env->sepc;
672     return 0;
673 }
674 
675 static int write_sepc(CPURISCVState *env, int csrno, target_ulong val)
676 {
677     env->sepc = val;
678     return 0;
679 }
680 
681 static int read_scause(CPURISCVState *env, int csrno, target_ulong *val)
682 {
683     *val = env->scause;
684     return 0;
685 }
686 
687 static int write_scause(CPURISCVState *env, int csrno, target_ulong val)
688 {
689     env->scause = val;
690     return 0;
691 }
692 
693 static int read_sbadaddr(CPURISCVState *env, int csrno, target_ulong *val)
694 {
695     *val = env->sbadaddr;
696     return 0;
697 }
698 
699 static int write_sbadaddr(CPURISCVState *env, int csrno, target_ulong val)
700 {
701     env->sbadaddr = val;
702     return 0;
703 }
704 
705 static int rmw_sip(CPURISCVState *env, int csrno, target_ulong *ret_value,
706                    target_ulong new_value, target_ulong write_mask)
707 {
708     int ret = rmw_mip(env, CSR_MSTATUS, ret_value, new_value,
709                       write_mask & env->mideleg & sip_writable_mask);
710     *ret_value &= env->mideleg;
711     return ret;
712 }
713 
714 /* Supervisor Protection and Translation */
715 static int read_satp(CPURISCVState *env, int csrno, target_ulong *val)
716 {
717     if (!riscv_feature(env, RISCV_FEATURE_MMU)) {
718         *val = 0;
719     } else if (env->priv_ver >= PRIV_VERSION_1_10_0) {
720         if (env->priv == PRV_S && get_field(env->mstatus, MSTATUS_TVM)) {
721             return -1;
722         } else {
723             *val = env->satp;
724         }
725     } else {
726         *val = env->sptbr;
727     }
728     return 0;
729 }
730 
731 static int write_satp(CPURISCVState *env, int csrno, target_ulong val)
732 {
733     if (!riscv_feature(env, RISCV_FEATURE_MMU)) {
734         return 0;
735     }
736     if (env->priv_ver <= PRIV_VERSION_1_09_1 && (val ^ env->sptbr)) {
737         tlb_flush(env_cpu(env));
738         env->sptbr = val & (((target_ulong)
739             1 << (TARGET_PHYS_ADDR_SPACE_BITS - PGSHIFT)) - 1);
740     }
741     if (env->priv_ver >= PRIV_VERSION_1_10_0 &&
742         validate_vm(env, get_field(val, SATP_MODE)) &&
743         ((val ^ env->satp) & (SATP_MODE | SATP_ASID | SATP_PPN)))
744     {
745         if (env->priv == PRV_S && get_field(env->mstatus, MSTATUS_TVM)) {
746             return -1;
747         } else {
748             if((val ^ env->satp) & SATP_ASID) {
749                 tlb_flush(env_cpu(env));
750             }
751             env->satp = val;
752         }
753     }
754     return 0;
755 }
756 
757 /* Physical Memory Protection */
758 static int read_pmpcfg(CPURISCVState *env, int csrno, target_ulong *val)
759 {
760     *val = pmpcfg_csr_read(env, csrno - CSR_PMPCFG0);
761     return 0;
762 }
763 
764 static int write_pmpcfg(CPURISCVState *env, int csrno, target_ulong val)
765 {
766     pmpcfg_csr_write(env, csrno - CSR_PMPCFG0, val);
767     return 0;
768 }
769 
770 static int read_pmpaddr(CPURISCVState *env, int csrno, target_ulong *val)
771 {
772     *val = pmpaddr_csr_read(env, csrno - CSR_PMPADDR0);
773     return 0;
774 }
775 
776 static int write_pmpaddr(CPURISCVState *env, int csrno, target_ulong val)
777 {
778     pmpaddr_csr_write(env, csrno - CSR_PMPADDR0, val);
779     return 0;
780 }
781 
782 #endif
783 
784 /*
785  * riscv_csrrw - read and/or update control and status register
786  *
787  * csrr   <->  riscv_csrrw(env, csrno, ret_value, 0, 0);
788  * csrrw  <->  riscv_csrrw(env, csrno, ret_value, value, -1);
789  * csrrs  <->  riscv_csrrw(env, csrno, ret_value, -1, value);
790  * csrrc  <->  riscv_csrrw(env, csrno, ret_value, 0, value);
791  */
792 
793 int riscv_csrrw(CPURISCVState *env, int csrno, target_ulong *ret_value,
794                 target_ulong new_value, target_ulong write_mask)
795 {
796     int ret;
797     target_ulong old_value;
798     RISCVCPU *cpu = env_archcpu(env);
799 
800     /* check privileges and return -1 if check fails */
801 #if !defined(CONFIG_USER_ONLY)
802     int csr_priv = get_field(csrno, 0x300);
803     int read_only = get_field(csrno, 0xC00) == 3;
804     if ((!env->debugger) && (env->priv < csr_priv)) {
805         return -1;
806     }
807     if (write_mask && read_only) {
808         return -1;
809     }
810 #endif
811 
812     /* ensure the CSR extension is enabled. */
813     if (!cpu->cfg.ext_icsr) {
814         return -1;
815     }
816 
817     /* check predicate */
818     if (!csr_ops[csrno].predicate || csr_ops[csrno].predicate(env, csrno) < 0) {
819         return -1;
820     }
821 
822     /* execute combined read/write operation if it exists */
823     if (csr_ops[csrno].op) {
824         return csr_ops[csrno].op(env, csrno, ret_value, new_value, write_mask);
825     }
826 
827     /* if no accessor exists then return failure */
828     if (!csr_ops[csrno].read) {
829         return -1;
830     }
831 
832     /* read old value */
833     ret = csr_ops[csrno].read(env, csrno, &old_value);
834     if (ret < 0) {
835         return ret;
836     }
837 
838     /* write value if writable and write mask set, otherwise drop writes */
839     if (write_mask) {
840         new_value = (old_value & ~write_mask) | (new_value & write_mask);
841         if (csr_ops[csrno].write) {
842             ret = csr_ops[csrno].write(env, csrno, new_value);
843             if (ret < 0) {
844                 return ret;
845             }
846         }
847     }
848 
849     /* return old value */
850     if (ret_value) {
851         *ret_value = old_value;
852     }
853 
854     return 0;
855 }
856 
857 /*
858  * Debugger support.  If not in user mode, set env->debugger before the
859  * riscv_csrrw call and clear it after the call.
860  */
861 int riscv_csrrw_debug(CPURISCVState *env, int csrno, target_ulong *ret_value,
862                 target_ulong new_value, target_ulong write_mask)
863 {
864     int ret;
865 #if !defined(CONFIG_USER_ONLY)
866     env->debugger = true;
867 #endif
868     ret = riscv_csrrw(env, csrno, ret_value, new_value, write_mask);
869 #if !defined(CONFIG_USER_ONLY)
870     env->debugger = false;
871 #endif
872     return ret;
873 }
874 
875 /* Control and Status Register function table */
876 static riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
877     /* User Floating-Point CSRs */
878     [CSR_FFLAGS] =              { fs,   read_fflags,      write_fflags      },
879     [CSR_FRM] =                 { fs,   read_frm,         write_frm         },
880     [CSR_FCSR] =                { fs,   read_fcsr,        write_fcsr        },
881 
882     /* User Timers and Counters */
883     [CSR_CYCLE] =               { ctr,  read_instret                        },
884     [CSR_INSTRET] =             { ctr,  read_instret                        },
885 #if defined(TARGET_RISCV32)
886     [CSR_CYCLEH] =              { ctr,  read_instreth                       },
887     [CSR_INSTRETH] =            { ctr,  read_instreth                       },
888 #endif
889 
890     /* User-level time CSRs are only available in linux-user
891      * In privileged mode, the monitor emulates these CSRs */
892 #if defined(CONFIG_USER_ONLY)
893     [CSR_TIME] =                { ctr,  read_time                           },
894 #if defined(TARGET_RISCV32)
895     [CSR_TIMEH] =               { ctr,  read_timeh                          },
896 #endif
897 #endif
898 
899 #if !defined(CONFIG_USER_ONLY)
900     /* Machine Timers and Counters */
901     [CSR_MCYCLE] =              { any,  read_instret                        },
902     [CSR_MINSTRET] =            { any,  read_instret                        },
903 #if defined(TARGET_RISCV32)
904     [CSR_MCYCLEH] =             { any,  read_instreth                       },
905     [CSR_MINSTRETH] =           { any,  read_instreth                       },
906 #endif
907 
908     /* Machine Information Registers */
909     [CSR_MVENDORID] =           { any,  read_zero                           },
910     [CSR_MARCHID] =             { any,  read_zero                           },
911     [CSR_MIMPID] =              { any,  read_zero                           },
912     [CSR_MHARTID] =             { any,  read_mhartid                        },
913 
914     /* Machine Trap Setup */
915     [CSR_MSTATUS] =             { any,  read_mstatus,     write_mstatus     },
916     [CSR_MISA] =                { any,  read_misa,        write_misa        },
917     [CSR_MIDELEG] =             { any,  read_mideleg,     write_mideleg     },
918     [CSR_MEDELEG] =             { any,  read_medeleg,     write_medeleg     },
919     [CSR_MIE] =                 { any,  read_mie,         write_mie         },
920     [CSR_MTVEC] =               { any,  read_mtvec,       write_mtvec       },
921     [CSR_MCOUNTEREN] =          { any,  read_mcounteren,  write_mcounteren  },
922 
923     /* Legacy Counter Setup (priv v1.9.1) */
924     [CSR_MUCOUNTEREN] =         { any,  read_mucounteren, write_mucounteren },
925     [CSR_MSCOUNTEREN] =         { any,  read_mscounteren, write_mscounteren },
926 
927     /* Machine Trap Handling */
928     [CSR_MSCRATCH] =            { any,  read_mscratch,    write_mscratch    },
929     [CSR_MEPC] =                { any,  read_mepc,        write_mepc        },
930     [CSR_MCAUSE] =              { any,  read_mcause,      write_mcause      },
931     [CSR_MBADADDR] =            { any,  read_mbadaddr,    write_mbadaddr    },
932     [CSR_MIP] =                 { any,  NULL,     NULL,     rmw_mip         },
933 
934     /* Supervisor Trap Setup */
935     [CSR_SSTATUS] =             { smode, read_sstatus,     write_sstatus     },
936     [CSR_SIE] =                 { smode, read_sie,         write_sie         },
937     [CSR_STVEC] =               { smode, read_stvec,       write_stvec       },
938     [CSR_SCOUNTEREN] =          { smode, read_scounteren,  write_scounteren  },
939 
940     /* Supervisor Trap Handling */
941     [CSR_SSCRATCH] =            { smode, read_sscratch,    write_sscratch    },
942     [CSR_SEPC] =                { smode, read_sepc,        write_sepc        },
943     [CSR_SCAUSE] =              { smode, read_scause,      write_scause      },
944     [CSR_SBADADDR] =            { smode, read_sbadaddr,    write_sbadaddr    },
945     [CSR_SIP] =                 { smode, NULL,     NULL,     rmw_sip         },
946 
947     /* Supervisor Protection and Translation */
948     [CSR_SATP] =                { smode, read_satp,        write_satp        },
949 
950     /* Physical Memory Protection */
951     [CSR_PMPCFG0  ... CSR_PMPADDR9] =  { pmp,   read_pmpcfg,  write_pmpcfg   },
952     [CSR_PMPADDR0 ... CSR_PMPADDR15] = { pmp,   read_pmpaddr, write_pmpaddr  },
953 
954     /* Performance Counters */
955     [CSR_HPMCOUNTER3   ... CSR_HPMCOUNTER31] =    { ctr,  read_zero          },
956     [CSR_MHPMCOUNTER3  ... CSR_MHPMCOUNTER31] =   { any,  read_zero          },
957     [CSR_MHPMEVENT3    ... CSR_MHPMEVENT31] =     { any,  read_zero          },
958 #if defined(TARGET_RISCV32)
959     [CSR_HPMCOUNTER3H  ... CSR_HPMCOUNTER31H] =   { ctr,  read_zero          },
960     [CSR_MHPMCOUNTER3H ... CSR_MHPMCOUNTER31H] =  { any,  read_zero          },
961 #endif
962 #endif /* !CONFIG_USER_ONLY */
963 };
964