xref: /openbmc/qemu/hw/intc/armv7m_nvic.c (revision 44b1ff31)
1 /*
2  * ARM Nested Vectored Interrupt Controller
3  *
4  * Copyright (c) 2006-2007 CodeSourcery.
5  * Written by Paul Brook
6  *
7  * This code is licensed under the GPL.
8  *
9  * The ARMv7M System controller is fairly tightly tied in with the
10  * NVIC.  Much of that is also implemented here.
11  */
12 
13 #include "qemu/osdep.h"
14 #include "qapi/error.h"
15 #include "qemu-common.h"
16 #include "cpu.h"
17 #include "hw/sysbus.h"
18 #include "qemu/timer.h"
19 #include "hw/arm/arm.h"
20 #include "hw/intc/armv7m_nvic.h"
21 #include "target/arm/cpu.h"
22 #include "exec/exec-all.h"
23 #include "qemu/log.h"
24 #include "trace.h"
25 
26 /* IRQ number counting:
27  *
28  * the num-irq property counts the number of external IRQ lines
29  *
30  * NVICState::num_irq counts the total number of exceptions
31  * (external IRQs, the 15 internal exceptions including reset,
32  * and one for the unused exception number 0).
33  *
34  * NVIC_MAX_IRQ is the highest permitted number of external IRQ lines.
35  *
36  * NVIC_MAX_VECTORS is the highest permitted number of exceptions.
37  *
38  * Iterating through all exceptions should typically be done with
39  * for (i = 1; i < s->num_irq; i++) to avoid the unused slot 0.
40  *
41  * The external qemu_irq lines are the NVIC's external IRQ lines,
42  * so line 0 is exception 16.
43  *
44  * In the terminology of the architecture manual, "interrupts" are
45  * a subcategory of exception referring to the external interrupts
46  * (which are exception numbers NVIC_FIRST_IRQ and upward).
47  * For historical reasons QEMU tends to use "interrupt" and
48  * "exception" more or less interchangeably.
49  */
50 #define NVIC_FIRST_IRQ NVIC_INTERNAL_VECTORS
51 #define NVIC_MAX_IRQ (NVIC_MAX_VECTORS - NVIC_FIRST_IRQ)
52 
53 /* Effective running priority of the CPU when no exception is active
54  * (higher than the highest possible priority value)
55  */
56 #define NVIC_NOEXC_PRIO 0x100
57 /* Maximum priority of non-secure exceptions when AIRCR.PRIS is set */
58 #define NVIC_NS_PRIO_LIMIT 0x80
59 
60 static const uint8_t nvic_id[] = {
61     0x00, 0xb0, 0x1b, 0x00, 0x0d, 0xe0, 0x05, 0xb1
62 };
63 
64 static int nvic_pending_prio(NVICState *s)
65 {
66     /* return the group priority of the current pending interrupt,
67      * or NVIC_NOEXC_PRIO if no interrupt is pending
68      */
69     return s->vectpending_prio;
70 }
71 
72 /* Return the value of the ISCR RETTOBASE bit:
73  * 1 if there is exactly one active exception
74  * 0 if there is more than one active exception
75  * UNKNOWN if there are no active exceptions (we choose 1,
76  * which matches the choice Cortex-M3 is documented as making).
77  *
78  * NB: some versions of the documentation talk about this
79  * counting "active exceptions other than the one shown by IPSR";
80  * this is only different in the obscure corner case where guest
81  * code has manually deactivated an exception and is about
82  * to fail an exception-return integrity check. The definition
83  * above is the one from the v8M ARM ARM and is also in line
84  * with the behaviour documented for the Cortex-M3.
85  */
86 static bool nvic_rettobase(NVICState *s)
87 {
88     int irq, nhand = 0;
89     bool check_sec = arm_feature(&s->cpu->env, ARM_FEATURE_M_SECURITY);
90 
91     for (irq = ARMV7M_EXCP_RESET; irq < s->num_irq; irq++) {
92         if (s->vectors[irq].active ||
93             (check_sec && irq < NVIC_INTERNAL_VECTORS &&
94              s->sec_vectors[irq].active)) {
95             nhand++;
96             if (nhand == 2) {
97                 return 0;
98             }
99         }
100     }
101 
102     return 1;
103 }
104 
105 /* Return the value of the ISCR ISRPENDING bit:
106  * 1 if an external interrupt is pending
107  * 0 if no external interrupt is pending
108  */
109 static bool nvic_isrpending(NVICState *s)
110 {
111     int irq;
112 
113     /* We can shortcut if the highest priority pending interrupt
114      * happens to be external or if there is nothing pending.
115      */
116     if (s->vectpending > NVIC_FIRST_IRQ) {
117         return true;
118     }
119     if (s->vectpending == 0) {
120         return false;
121     }
122 
123     for (irq = NVIC_FIRST_IRQ; irq < s->num_irq; irq++) {
124         if (s->vectors[irq].pending) {
125             return true;
126         }
127     }
128     return false;
129 }
130 
131 static bool exc_is_banked(int exc)
132 {
133     /* Return true if this is one of the limited set of exceptions which
134      * are banked (and thus have state in sec_vectors[])
135      */
136     return exc == ARMV7M_EXCP_HARD ||
137         exc == ARMV7M_EXCP_MEM ||
138         exc == ARMV7M_EXCP_USAGE ||
139         exc == ARMV7M_EXCP_SVC ||
140         exc == ARMV7M_EXCP_PENDSV ||
141         exc == ARMV7M_EXCP_SYSTICK;
142 }
143 
144 /* Return a mask word which clears the subpriority bits from
145  * a priority value for an M-profile exception, leaving only
146  * the group priority.
147  */
148 static inline uint32_t nvic_gprio_mask(NVICState *s, bool secure)
149 {
150     return ~0U << (s->prigroup[secure] + 1);
151 }
152 
153 static bool exc_targets_secure(NVICState *s, int exc)
154 {
155     /* Return true if this non-banked exception targets Secure state. */
156     if (!arm_feature(&s->cpu->env, ARM_FEATURE_M_SECURITY)) {
157         return false;
158     }
159 
160     if (exc >= NVIC_FIRST_IRQ) {
161         return !s->itns[exc];
162     }
163 
164     /* Function shouldn't be called for banked exceptions. */
165     assert(!exc_is_banked(exc));
166 
167     switch (exc) {
168     case ARMV7M_EXCP_NMI:
169     case ARMV7M_EXCP_BUS:
170         return !(s->cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK);
171     case ARMV7M_EXCP_SECURE:
172         return true;
173     case ARMV7M_EXCP_DEBUG:
174         /* TODO: controlled by DEMCR.SDME, which we don't yet implement */
175         return false;
176     default:
177         /* reset, and reserved (unused) low exception numbers.
178          * We'll get called by code that loops through all the exception
179          * numbers, but it doesn't matter what we return here as these
180          * non-existent exceptions will never be pended or active.
181          */
182         return true;
183     }
184 }
185 
186 static int exc_group_prio(NVICState *s, int rawprio, bool targets_secure)
187 {
188     /* Return the group priority for this exception, given its raw
189      * (group-and-subgroup) priority value and whether it is targeting
190      * secure state or not.
191      */
192     if (rawprio < 0) {
193         return rawprio;
194     }
195     rawprio &= nvic_gprio_mask(s, targets_secure);
196     /* AIRCR.PRIS causes us to squash all NS priorities into the
197      * lower half of the total range
198      */
199     if (!targets_secure &&
200         (s->cpu->env.v7m.aircr & R_V7M_AIRCR_PRIS_MASK)) {
201         rawprio = (rawprio >> 1) + NVIC_NS_PRIO_LIMIT;
202     }
203     return rawprio;
204 }
205 
206 /* Recompute vectpending and exception_prio for a CPU which implements
207  * the Security extension
208  */
209 static void nvic_recompute_state_secure(NVICState *s)
210 {
211     int i, bank;
212     int pend_prio = NVIC_NOEXC_PRIO;
213     int active_prio = NVIC_NOEXC_PRIO;
214     int pend_irq = 0;
215     bool pending_is_s_banked = false;
216 
217     /* R_CQRV: precedence is by:
218      *  - lowest group priority; if both the same then
219      *  - lowest subpriority; if both the same then
220      *  - lowest exception number; if both the same (ie banked) then
221      *  - secure exception takes precedence
222      * Compare pseudocode RawExecutionPriority.
223      * Annoyingly, now we have two prigroup values (for S and NS)
224      * we can't do the loop comparison on raw priority values.
225      */
226     for (i = 1; i < s->num_irq; i++) {
227         for (bank = M_REG_S; bank >= M_REG_NS; bank--) {
228             VecInfo *vec;
229             int prio;
230             bool targets_secure;
231 
232             if (bank == M_REG_S) {
233                 if (!exc_is_banked(i)) {
234                     continue;
235                 }
236                 vec = &s->sec_vectors[i];
237                 targets_secure = true;
238             } else {
239                 vec = &s->vectors[i];
240                 targets_secure = !exc_is_banked(i) && exc_targets_secure(s, i);
241             }
242 
243             prio = exc_group_prio(s, vec->prio, targets_secure);
244             if (vec->enabled && vec->pending && prio < pend_prio) {
245                 pend_prio = prio;
246                 pend_irq = i;
247                 pending_is_s_banked = (bank == M_REG_S);
248             }
249             if (vec->active && prio < active_prio) {
250                 active_prio = prio;
251             }
252         }
253     }
254 
255     s->vectpending_is_s_banked = pending_is_s_banked;
256     s->vectpending = pend_irq;
257     s->vectpending_prio = pend_prio;
258     s->exception_prio = active_prio;
259 
260     trace_nvic_recompute_state_secure(s->vectpending,
261                                       s->vectpending_is_s_banked,
262                                       s->vectpending_prio,
263                                       s->exception_prio);
264 }
265 
266 /* Recompute vectpending and exception_prio */
267 static void nvic_recompute_state(NVICState *s)
268 {
269     int i;
270     int pend_prio = NVIC_NOEXC_PRIO;
271     int active_prio = NVIC_NOEXC_PRIO;
272     int pend_irq = 0;
273 
274     /* In theory we could write one function that handled both
275      * the "security extension present" and "not present"; however
276      * the security related changes significantly complicate the
277      * recomputation just by themselves and mixing both cases together
278      * would be even worse, so we retain a separate non-secure-only
279      * version for CPUs which don't implement the security extension.
280      */
281     if (arm_feature(&s->cpu->env, ARM_FEATURE_M_SECURITY)) {
282         nvic_recompute_state_secure(s);
283         return;
284     }
285 
286     for (i = 1; i < s->num_irq; i++) {
287         VecInfo *vec = &s->vectors[i];
288 
289         if (vec->enabled && vec->pending && vec->prio < pend_prio) {
290             pend_prio = vec->prio;
291             pend_irq = i;
292         }
293         if (vec->active && vec->prio < active_prio) {
294             active_prio = vec->prio;
295         }
296     }
297 
298     if (active_prio > 0) {
299         active_prio &= nvic_gprio_mask(s, false);
300     }
301 
302     if (pend_prio > 0) {
303         pend_prio &= nvic_gprio_mask(s, false);
304     }
305 
306     s->vectpending = pend_irq;
307     s->vectpending_prio = pend_prio;
308     s->exception_prio = active_prio;
309 
310     trace_nvic_recompute_state(s->vectpending,
311                                s->vectpending_prio,
312                                s->exception_prio);
313 }
314 
315 /* Return the current execution priority of the CPU
316  * (equivalent to the pseudocode ExecutionPriority function).
317  * This is a value between -2 (NMI priority) and NVIC_NOEXC_PRIO.
318  */
319 static inline int nvic_exec_prio(NVICState *s)
320 {
321     CPUARMState *env = &s->cpu->env;
322     int running = NVIC_NOEXC_PRIO;
323 
324     if (env->v7m.basepri[M_REG_NS] > 0) {
325         running = exc_group_prio(s, env->v7m.basepri[M_REG_NS], M_REG_NS);
326     }
327 
328     if (env->v7m.basepri[M_REG_S] > 0) {
329         int basepri = exc_group_prio(s, env->v7m.basepri[M_REG_S], M_REG_S);
330         if (running > basepri) {
331             running = basepri;
332         }
333     }
334 
335     if (env->v7m.primask[M_REG_NS]) {
336         if (env->v7m.aircr & R_V7M_AIRCR_PRIS_MASK) {
337             if (running > NVIC_NS_PRIO_LIMIT) {
338                 running = NVIC_NS_PRIO_LIMIT;
339             }
340         } else {
341             running = 0;
342         }
343     }
344 
345     if (env->v7m.primask[M_REG_S]) {
346         running = 0;
347     }
348 
349     if (env->v7m.faultmask[M_REG_NS]) {
350         if (env->v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK) {
351             running = -1;
352         } else {
353             if (env->v7m.aircr & R_V7M_AIRCR_PRIS_MASK) {
354                 if (running > NVIC_NS_PRIO_LIMIT) {
355                     running = NVIC_NS_PRIO_LIMIT;
356                 }
357             } else {
358                 running = 0;
359             }
360         }
361     }
362 
363     if (env->v7m.faultmask[M_REG_S]) {
364         running = (env->v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK) ? -3 : -1;
365     }
366 
367     /* consider priority of active handler */
368     return MIN(running, s->exception_prio);
369 }
370 
371 bool armv7m_nvic_neg_prio_requested(void *opaque, bool secure)
372 {
373     /* Return true if the requested execution priority is negative
374      * for the specified security state, ie that security state
375      * has an active NMI or HardFault or has set its FAULTMASK.
376      * Note that this is not the same as whether the execution
377      * priority is actually negative (for instance AIRCR.PRIS may
378      * mean we don't allow FAULTMASK_NS to actually make the execution
379      * priority negative). Compare pseudocode IsReqExcPriNeg().
380      */
381     NVICState *s = opaque;
382 
383     if (s->cpu->env.v7m.faultmask[secure]) {
384         return true;
385     }
386 
387     if (secure ? s->sec_vectors[ARMV7M_EXCP_HARD].active :
388         s->vectors[ARMV7M_EXCP_HARD].active) {
389         return true;
390     }
391 
392     if (s->vectors[ARMV7M_EXCP_NMI].active &&
393         exc_targets_secure(s, ARMV7M_EXCP_NMI) == secure) {
394         return true;
395     }
396 
397     return false;
398 }
399 
400 bool armv7m_nvic_can_take_pending_exception(void *opaque)
401 {
402     NVICState *s = opaque;
403 
404     return nvic_exec_prio(s) > nvic_pending_prio(s);
405 }
406 
407 int armv7m_nvic_raw_execution_priority(void *opaque)
408 {
409     NVICState *s = opaque;
410 
411     return s->exception_prio;
412 }
413 
414 /* caller must call nvic_irq_update() after this.
415  * secure indicates the bank to use for banked exceptions (we assert if
416  * we are passed secure=true for a non-banked exception).
417  */
418 static void set_prio(NVICState *s, unsigned irq, bool secure, uint8_t prio)
419 {
420     assert(irq > ARMV7M_EXCP_NMI); /* only use for configurable prios */
421     assert(irq < s->num_irq);
422 
423     if (secure) {
424         assert(exc_is_banked(irq));
425         s->sec_vectors[irq].prio = prio;
426     } else {
427         s->vectors[irq].prio = prio;
428     }
429 
430     trace_nvic_set_prio(irq, secure, prio);
431 }
432 
433 /* Return the current raw priority register value.
434  * secure indicates the bank to use for banked exceptions (we assert if
435  * we are passed secure=true for a non-banked exception).
436  */
437 static int get_prio(NVICState *s, unsigned irq, bool secure)
438 {
439     assert(irq > ARMV7M_EXCP_NMI); /* only use for configurable prios */
440     assert(irq < s->num_irq);
441 
442     if (secure) {
443         assert(exc_is_banked(irq));
444         return s->sec_vectors[irq].prio;
445     } else {
446         return s->vectors[irq].prio;
447     }
448 }
449 
450 /* Recompute state and assert irq line accordingly.
451  * Must be called after changes to:
452  *  vec->active, vec->enabled, vec->pending or vec->prio for any vector
453  *  prigroup
454  */
455 static void nvic_irq_update(NVICState *s)
456 {
457     int lvl;
458     int pend_prio;
459 
460     nvic_recompute_state(s);
461     pend_prio = nvic_pending_prio(s);
462 
463     /* Raise NVIC output if this IRQ would be taken, except that we
464      * ignore the effects of the BASEPRI, FAULTMASK and PRIMASK (which
465      * will be checked for in arm_v7m_cpu_exec_interrupt()); changes
466      * to those CPU registers don't cause us to recalculate the NVIC
467      * pending info.
468      */
469     lvl = (pend_prio < s->exception_prio);
470     trace_nvic_irq_update(s->vectpending, pend_prio, s->exception_prio, lvl);
471     qemu_set_irq(s->excpout, lvl);
472 }
473 
474 /**
475  * armv7m_nvic_clear_pending: mark the specified exception as not pending
476  * @opaque: the NVIC
477  * @irq: the exception number to mark as not pending
478  * @secure: false for non-banked exceptions or for the nonsecure
479  * version of a banked exception, true for the secure version of a banked
480  * exception.
481  *
482  * Marks the specified exception as not pending. Note that we will assert()
483  * if @secure is true and @irq does not specify one of the fixed set
484  * of architecturally banked exceptions.
485  */
486 static void armv7m_nvic_clear_pending(void *opaque, int irq, bool secure)
487 {
488     NVICState *s = (NVICState *)opaque;
489     VecInfo *vec;
490 
491     assert(irq > ARMV7M_EXCP_RESET && irq < s->num_irq);
492 
493     if (secure) {
494         assert(exc_is_banked(irq));
495         vec = &s->sec_vectors[irq];
496     } else {
497         vec = &s->vectors[irq];
498     }
499     trace_nvic_clear_pending(irq, secure, vec->enabled, vec->prio);
500     if (vec->pending) {
501         vec->pending = 0;
502         nvic_irq_update(s);
503     }
504 }
505 
506 void armv7m_nvic_set_pending(void *opaque, int irq, bool secure)
507 {
508     NVICState *s = (NVICState *)opaque;
509     bool banked = exc_is_banked(irq);
510     VecInfo *vec;
511 
512     assert(irq > ARMV7M_EXCP_RESET && irq < s->num_irq);
513     assert(!secure || banked);
514 
515     vec = (banked && secure) ? &s->sec_vectors[irq] : &s->vectors[irq];
516 
517     trace_nvic_set_pending(irq, secure, vec->enabled, vec->prio);
518 
519     if (irq >= ARMV7M_EXCP_HARD && irq < ARMV7M_EXCP_PENDSV) {
520         /* If a synchronous exception is pending then it may be
521          * escalated to HardFault if:
522          *  * it is equal or lower priority to current execution
523          *  * it is disabled
524          * (ie we need to take it immediately but we can't do so).
525          * Asynchronous exceptions (and interrupts) simply remain pending.
526          *
527          * For QEMU, we don't have any imprecise (asynchronous) faults,
528          * so we can assume that PREFETCH_ABORT and DATA_ABORT are always
529          * synchronous.
530          * Debug exceptions are awkward because only Debug exceptions
531          * resulting from the BKPT instruction should be escalated,
532          * but we don't currently implement any Debug exceptions other
533          * than those that result from BKPT, so we treat all debug exceptions
534          * as needing escalation.
535          *
536          * This all means we can identify whether to escalate based only on
537          * the exception number and don't (yet) need the caller to explicitly
538          * tell us whether this exception is synchronous or not.
539          */
540         int running = nvic_exec_prio(s);
541         bool escalate = false;
542 
543         if (exc_group_prio(s, vec->prio, secure) >= running) {
544             trace_nvic_escalate_prio(irq, vec->prio, running);
545             escalate = true;
546         } else if (!vec->enabled) {
547             trace_nvic_escalate_disabled(irq);
548             escalate = true;
549         }
550 
551         if (escalate) {
552 
553             /* We need to escalate this exception to a synchronous HardFault.
554              * If BFHFNMINS is set then we escalate to the banked HF for
555              * the target security state of the original exception; otherwise
556              * we take a Secure HardFault.
557              */
558             irq = ARMV7M_EXCP_HARD;
559             if (arm_feature(&s->cpu->env, ARM_FEATURE_M_SECURITY) &&
560                 (secure ||
561                  !(s->cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK))) {
562                 vec = &s->sec_vectors[irq];
563             } else {
564                 vec = &s->vectors[irq];
565             }
566             if (running <= vec->prio) {
567                 /* We want to escalate to HardFault but we can't take the
568                  * synchronous HardFault at this point either. This is a
569                  * Lockup condition due to a guest bug. We don't model
570                  * Lockup, so report via cpu_abort() instead.
571                  */
572                 cpu_abort(&s->cpu->parent_obj,
573                           "Lockup: can't escalate %d to HardFault "
574                           "(current priority %d)\n", irq, running);
575             }
576 
577             /* HF may be banked but there is only one shared HFSR */
578             s->cpu->env.v7m.hfsr |= R_V7M_HFSR_FORCED_MASK;
579         }
580     }
581 
582     if (!vec->pending) {
583         vec->pending = 1;
584         nvic_irq_update(s);
585     }
586 }
587 
588 /* Make pending IRQ active.  */
589 bool armv7m_nvic_acknowledge_irq(void *opaque)
590 {
591     NVICState *s = (NVICState *)opaque;
592     CPUARMState *env = &s->cpu->env;
593     const int pending = s->vectpending;
594     const int running = nvic_exec_prio(s);
595     VecInfo *vec;
596     bool targets_secure;
597 
598     assert(pending > ARMV7M_EXCP_RESET && pending < s->num_irq);
599 
600     if (s->vectpending_is_s_banked) {
601         vec = &s->sec_vectors[pending];
602         targets_secure = true;
603     } else {
604         vec = &s->vectors[pending];
605         targets_secure = !exc_is_banked(s->vectpending) &&
606             exc_targets_secure(s, s->vectpending);
607     }
608 
609     assert(vec->enabled);
610     assert(vec->pending);
611 
612     assert(s->vectpending_prio < running);
613 
614     trace_nvic_acknowledge_irq(pending, s->vectpending_prio, targets_secure);
615 
616     vec->active = 1;
617     vec->pending = 0;
618 
619     env->v7m.exception = s->vectpending;
620 
621     nvic_irq_update(s);
622 
623     return targets_secure;
624 }
625 
626 int armv7m_nvic_complete_irq(void *opaque, int irq, bool secure)
627 {
628     NVICState *s = (NVICState *)opaque;
629     VecInfo *vec;
630     int ret;
631 
632     assert(irq > ARMV7M_EXCP_RESET && irq < s->num_irq);
633 
634     if (secure && exc_is_banked(irq)) {
635         vec = &s->sec_vectors[irq];
636     } else {
637         vec = &s->vectors[irq];
638     }
639 
640     trace_nvic_complete_irq(irq, secure);
641 
642     if (!vec->active) {
643         /* Tell the caller this was an illegal exception return */
644         return -1;
645     }
646 
647     ret = nvic_rettobase(s);
648 
649     vec->active = 0;
650     if (vec->level) {
651         /* Re-pend the exception if it's still held high; only
652          * happens for extenal IRQs
653          */
654         assert(irq >= NVIC_FIRST_IRQ);
655         vec->pending = 1;
656     }
657 
658     nvic_irq_update(s);
659 
660     return ret;
661 }
662 
663 /* callback when external interrupt line is changed */
664 static void set_irq_level(void *opaque, int n, int level)
665 {
666     NVICState *s = opaque;
667     VecInfo *vec;
668 
669     n += NVIC_FIRST_IRQ;
670 
671     assert(n >= NVIC_FIRST_IRQ && n < s->num_irq);
672 
673     trace_nvic_set_irq_level(n, level);
674 
675     /* The pending status of an external interrupt is
676      * latched on rising edge and exception handler return.
677      *
678      * Pulsing the IRQ will always run the handler
679      * once, and the handler will re-run until the
680      * level is low when the handler completes.
681      */
682     vec = &s->vectors[n];
683     if (level != vec->level) {
684         vec->level = level;
685         if (level) {
686             armv7m_nvic_set_pending(s, n, false);
687         }
688     }
689 }
690 
691 static uint32_t nvic_readl(NVICState *s, uint32_t offset, MemTxAttrs attrs)
692 {
693     ARMCPU *cpu = s->cpu;
694     uint32_t val;
695 
696     switch (offset) {
697     case 4: /* Interrupt Control Type.  */
698         return ((s->num_irq - NVIC_FIRST_IRQ) / 32) - 1;
699     case 0x380 ... 0x3bf: /* NVIC_ITNS<n> */
700     {
701         int startvec = 32 * (offset - 0x380) + NVIC_FIRST_IRQ;
702         int i;
703 
704         if (!arm_feature(&cpu->env, ARM_FEATURE_V8)) {
705             goto bad_offset;
706         }
707         if (!attrs.secure) {
708             return 0;
709         }
710         val = 0;
711         for (i = 0; i < 32 && startvec + i < s->num_irq; i++) {
712             if (s->itns[startvec + i]) {
713                 val |= (1 << i);
714             }
715         }
716         return val;
717     }
718     case 0xd00: /* CPUID Base.  */
719         return cpu->midr;
720     case 0xd04: /* Interrupt Control State (ICSR) */
721         /* VECTACTIVE */
722         val = cpu->env.v7m.exception;
723         /* VECTPENDING */
724         val |= (s->vectpending & 0xff) << 12;
725         /* ISRPENDING - set if any external IRQ is pending */
726         if (nvic_isrpending(s)) {
727             val |= (1 << 22);
728         }
729         /* RETTOBASE - set if only one handler is active */
730         if (nvic_rettobase(s)) {
731             val |= (1 << 11);
732         }
733         if (attrs.secure) {
734             /* PENDSTSET */
735             if (s->sec_vectors[ARMV7M_EXCP_SYSTICK].pending) {
736                 val |= (1 << 26);
737             }
738             /* PENDSVSET */
739             if (s->sec_vectors[ARMV7M_EXCP_PENDSV].pending) {
740                 val |= (1 << 28);
741             }
742         } else {
743             /* PENDSTSET */
744             if (s->vectors[ARMV7M_EXCP_SYSTICK].pending) {
745                 val |= (1 << 26);
746             }
747             /* PENDSVSET */
748             if (s->vectors[ARMV7M_EXCP_PENDSV].pending) {
749                 val |= (1 << 28);
750             }
751         }
752         /* NMIPENDSET */
753         if ((cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK) &&
754             s->vectors[ARMV7M_EXCP_NMI].pending) {
755             val |= (1 << 31);
756         }
757         /* ISRPREEMPT: RES0 when halting debug not implemented */
758         /* STTNS: RES0 for the Main Extension */
759         return val;
760     case 0xd08: /* Vector Table Offset.  */
761         return cpu->env.v7m.vecbase[attrs.secure];
762     case 0xd0c: /* Application Interrupt/Reset Control (AIRCR) */
763         val = 0xfa050000 | (s->prigroup[attrs.secure] << 8);
764         if (attrs.secure) {
765             /* s->aircr stores PRIS, BFHFNMINS, SYSRESETREQS */
766             val |= cpu->env.v7m.aircr;
767         } else {
768             if (arm_feature(&cpu->env, ARM_FEATURE_V8)) {
769                 /* BFHFNMINS is R/O from NS; other bits are RAZ/WI. If
770                  * security isn't supported then BFHFNMINS is RAO (and
771                  * the bit in env.v7m.aircr is always set).
772                  */
773                 val |= cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK;
774             }
775         }
776         return val;
777     case 0xd10: /* System Control.  */
778         /* TODO: Implement SLEEPONEXIT.  */
779         return 0;
780     case 0xd14: /* Configuration Control.  */
781         /* The BFHFNMIGN bit is the only non-banked bit; we
782          * keep it in the non-secure copy of the register.
783          */
784         val = cpu->env.v7m.ccr[attrs.secure];
785         val |= cpu->env.v7m.ccr[M_REG_NS] & R_V7M_CCR_BFHFNMIGN_MASK;
786         return val;
787     case 0xd24: /* System Handler Control and State (SHCSR) */
788         val = 0;
789         if (attrs.secure) {
790             if (s->sec_vectors[ARMV7M_EXCP_MEM].active) {
791                 val |= (1 << 0);
792             }
793             if (s->sec_vectors[ARMV7M_EXCP_HARD].active) {
794                 val |= (1 << 2);
795             }
796             if (s->sec_vectors[ARMV7M_EXCP_USAGE].active) {
797                 val |= (1 << 3);
798             }
799             if (s->sec_vectors[ARMV7M_EXCP_SVC].active) {
800                 val |= (1 << 7);
801             }
802             if (s->sec_vectors[ARMV7M_EXCP_PENDSV].active) {
803                 val |= (1 << 10);
804             }
805             if (s->sec_vectors[ARMV7M_EXCP_SYSTICK].active) {
806                 val |= (1 << 11);
807             }
808             if (s->sec_vectors[ARMV7M_EXCP_USAGE].pending) {
809                 val |= (1 << 12);
810             }
811             if (s->sec_vectors[ARMV7M_EXCP_MEM].pending) {
812                 val |= (1 << 13);
813             }
814             if (s->sec_vectors[ARMV7M_EXCP_SVC].pending) {
815                 val |= (1 << 15);
816             }
817             if (s->sec_vectors[ARMV7M_EXCP_MEM].enabled) {
818                 val |= (1 << 16);
819             }
820             if (s->sec_vectors[ARMV7M_EXCP_USAGE].enabled) {
821                 val |= (1 << 18);
822             }
823             if (s->sec_vectors[ARMV7M_EXCP_HARD].pending) {
824                 val |= (1 << 21);
825             }
826             /* SecureFault is not banked but is always RAZ/WI to NS */
827             if (s->vectors[ARMV7M_EXCP_SECURE].active) {
828                 val |= (1 << 4);
829             }
830             if (s->vectors[ARMV7M_EXCP_SECURE].enabled) {
831                 val |= (1 << 19);
832             }
833             if (s->vectors[ARMV7M_EXCP_SECURE].pending) {
834                 val |= (1 << 20);
835             }
836         } else {
837             if (s->vectors[ARMV7M_EXCP_MEM].active) {
838                 val |= (1 << 0);
839             }
840             if (arm_feature(&cpu->env, ARM_FEATURE_V8)) {
841                 /* HARDFAULTACT, HARDFAULTPENDED not present in v7M */
842                 if (s->vectors[ARMV7M_EXCP_HARD].active) {
843                     val |= (1 << 2);
844                 }
845                 if (s->vectors[ARMV7M_EXCP_HARD].pending) {
846                     val |= (1 << 21);
847                 }
848             }
849             if (s->vectors[ARMV7M_EXCP_USAGE].active) {
850                 val |= (1 << 3);
851             }
852             if (s->vectors[ARMV7M_EXCP_SVC].active) {
853                 val |= (1 << 7);
854             }
855             if (s->vectors[ARMV7M_EXCP_PENDSV].active) {
856                 val |= (1 << 10);
857             }
858             if (s->vectors[ARMV7M_EXCP_SYSTICK].active) {
859                 val |= (1 << 11);
860             }
861             if (s->vectors[ARMV7M_EXCP_USAGE].pending) {
862                 val |= (1 << 12);
863             }
864             if (s->vectors[ARMV7M_EXCP_MEM].pending) {
865                 val |= (1 << 13);
866             }
867             if (s->vectors[ARMV7M_EXCP_SVC].pending) {
868                 val |= (1 << 15);
869             }
870             if (s->vectors[ARMV7M_EXCP_MEM].enabled) {
871                 val |= (1 << 16);
872             }
873             if (s->vectors[ARMV7M_EXCP_USAGE].enabled) {
874                 val |= (1 << 18);
875             }
876         }
877         if (attrs.secure || (cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK)) {
878             if (s->vectors[ARMV7M_EXCP_BUS].active) {
879                 val |= (1 << 1);
880             }
881             if (s->vectors[ARMV7M_EXCP_BUS].pending) {
882                 val |= (1 << 14);
883             }
884             if (s->vectors[ARMV7M_EXCP_BUS].enabled) {
885                 val |= (1 << 17);
886             }
887             if (arm_feature(&cpu->env, ARM_FEATURE_V8) &&
888                 s->vectors[ARMV7M_EXCP_NMI].active) {
889                 /* NMIACT is not present in v7M */
890                 val |= (1 << 5);
891             }
892         }
893 
894         /* TODO: this is RAZ/WI from NS if DEMCR.SDME is set */
895         if (s->vectors[ARMV7M_EXCP_DEBUG].active) {
896             val |= (1 << 8);
897         }
898         return val;
899     case 0xd28: /* Configurable Fault Status.  */
900         /* The BFSR bits [15:8] are shared between security states
901          * and we store them in the NS copy
902          */
903         val = cpu->env.v7m.cfsr[attrs.secure];
904         val |= cpu->env.v7m.cfsr[M_REG_NS] & R_V7M_CFSR_BFSR_MASK;
905         return val;
906     case 0xd2c: /* Hard Fault Status.  */
907         return cpu->env.v7m.hfsr;
908     case 0xd30: /* Debug Fault Status.  */
909         return cpu->env.v7m.dfsr;
910     case 0xd34: /* MMFAR MemManage Fault Address */
911         return cpu->env.v7m.mmfar[attrs.secure];
912     case 0xd38: /* Bus Fault Address.  */
913         return cpu->env.v7m.bfar;
914     case 0xd3c: /* Aux Fault Status.  */
915         /* TODO: Implement fault status registers.  */
916         qemu_log_mask(LOG_UNIMP,
917                       "Aux Fault status registers unimplemented\n");
918         return 0;
919     case 0xd40: /* PFR0.  */
920         return 0x00000030;
921     case 0xd44: /* PRF1.  */
922         return 0x00000200;
923     case 0xd48: /* DFR0.  */
924         return 0x00100000;
925     case 0xd4c: /* AFR0.  */
926         return 0x00000000;
927     case 0xd50: /* MMFR0.  */
928         return 0x00000030;
929     case 0xd54: /* MMFR1.  */
930         return 0x00000000;
931     case 0xd58: /* MMFR2.  */
932         return 0x00000000;
933     case 0xd5c: /* MMFR3.  */
934         return 0x00000000;
935     case 0xd60: /* ISAR0.  */
936         return 0x01141110;
937     case 0xd64: /* ISAR1.  */
938         return 0x02111000;
939     case 0xd68: /* ISAR2.  */
940         return 0x21112231;
941     case 0xd6c: /* ISAR3.  */
942         return 0x01111110;
943     case 0xd70: /* ISAR4.  */
944         return 0x01310102;
945     /* TODO: Implement debug registers.  */
946     case 0xd90: /* MPU_TYPE */
947         /* Unified MPU; if the MPU is not present this value is zero */
948         return cpu->pmsav7_dregion << 8;
949         break;
950     case 0xd94: /* MPU_CTRL */
951         return cpu->env.v7m.mpu_ctrl[attrs.secure];
952     case 0xd98: /* MPU_RNR */
953         return cpu->env.pmsav7.rnr[attrs.secure];
954     case 0xd9c: /* MPU_RBAR */
955     case 0xda4: /* MPU_RBAR_A1 */
956     case 0xdac: /* MPU_RBAR_A2 */
957     case 0xdb4: /* MPU_RBAR_A3 */
958     {
959         int region = cpu->env.pmsav7.rnr[attrs.secure];
960 
961         if (arm_feature(&cpu->env, ARM_FEATURE_V8)) {
962             /* PMSAv8M handling of the aliases is different from v7M:
963              * aliases A1, A2, A3 override the low two bits of the region
964              * number in MPU_RNR, and there is no 'region' field in the
965              * RBAR register.
966              */
967             int aliasno = (offset - 0xd9c) / 8; /* 0..3 */
968             if (aliasno) {
969                 region = deposit32(region, 0, 2, aliasno);
970             }
971             if (region >= cpu->pmsav7_dregion) {
972                 return 0;
973             }
974             return cpu->env.pmsav8.rbar[attrs.secure][region];
975         }
976 
977         if (region >= cpu->pmsav7_dregion) {
978             return 0;
979         }
980         return (cpu->env.pmsav7.drbar[region] & 0x1f) | (region & 0xf);
981     }
982     case 0xda0: /* MPU_RASR (v7M), MPU_RLAR (v8M) */
983     case 0xda8: /* MPU_RASR_A1 (v7M), MPU_RLAR_A1 (v8M) */
984     case 0xdb0: /* MPU_RASR_A2 (v7M), MPU_RLAR_A2 (v8M) */
985     case 0xdb8: /* MPU_RASR_A3 (v7M), MPU_RLAR_A3 (v8M) */
986     {
987         int region = cpu->env.pmsav7.rnr[attrs.secure];
988 
989         if (arm_feature(&cpu->env, ARM_FEATURE_V8)) {
990             /* PMSAv8M handling of the aliases is different from v7M:
991              * aliases A1, A2, A3 override the low two bits of the region
992              * number in MPU_RNR.
993              */
994             int aliasno = (offset - 0xda0) / 8; /* 0..3 */
995             if (aliasno) {
996                 region = deposit32(region, 0, 2, aliasno);
997             }
998             if (region >= cpu->pmsav7_dregion) {
999                 return 0;
1000             }
1001             return cpu->env.pmsav8.rlar[attrs.secure][region];
1002         }
1003 
1004         if (region >= cpu->pmsav7_dregion) {
1005             return 0;
1006         }
1007         return ((cpu->env.pmsav7.dracr[region] & 0xffff) << 16) |
1008             (cpu->env.pmsav7.drsr[region] & 0xffff);
1009     }
1010     case 0xdc0: /* MPU_MAIR0 */
1011         if (!arm_feature(&cpu->env, ARM_FEATURE_V8)) {
1012             goto bad_offset;
1013         }
1014         return cpu->env.pmsav8.mair0[attrs.secure];
1015     case 0xdc4: /* MPU_MAIR1 */
1016         if (!arm_feature(&cpu->env, ARM_FEATURE_V8)) {
1017             goto bad_offset;
1018         }
1019         return cpu->env.pmsav8.mair1[attrs.secure];
1020     default:
1021     bad_offset:
1022         qemu_log_mask(LOG_GUEST_ERROR, "NVIC: Bad read offset 0x%x\n", offset);
1023         return 0;
1024     }
1025 }
1026 
1027 static void nvic_writel(NVICState *s, uint32_t offset, uint32_t value,
1028                         MemTxAttrs attrs)
1029 {
1030     ARMCPU *cpu = s->cpu;
1031 
1032     switch (offset) {
1033     case 0x380 ... 0x3bf: /* NVIC_ITNS<n> */
1034     {
1035         int startvec = 32 * (offset - 0x380) + NVIC_FIRST_IRQ;
1036         int i;
1037 
1038         if (!arm_feature(&cpu->env, ARM_FEATURE_V8)) {
1039             goto bad_offset;
1040         }
1041         if (!attrs.secure) {
1042             break;
1043         }
1044         for (i = 0; i < 32 && startvec + i < s->num_irq; i++) {
1045             s->itns[startvec + i] = (value >> i) & 1;
1046         }
1047         nvic_irq_update(s);
1048         break;
1049     }
1050     case 0xd04: /* Interrupt Control State (ICSR) */
1051         if (cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK) {
1052             if (value & (1 << 31)) {
1053                 armv7m_nvic_set_pending(s, ARMV7M_EXCP_NMI, false);
1054             } else if (value & (1 << 30) &&
1055                        arm_feature(&cpu->env, ARM_FEATURE_V8)) {
1056                 /* PENDNMICLR didn't exist in v7M */
1057                 armv7m_nvic_clear_pending(s, ARMV7M_EXCP_NMI, false);
1058             }
1059         }
1060         if (value & (1 << 28)) {
1061             armv7m_nvic_set_pending(s, ARMV7M_EXCP_PENDSV, attrs.secure);
1062         } else if (value & (1 << 27)) {
1063             armv7m_nvic_clear_pending(s, ARMV7M_EXCP_PENDSV, attrs.secure);
1064         }
1065         if (value & (1 << 26)) {
1066             armv7m_nvic_set_pending(s, ARMV7M_EXCP_SYSTICK, attrs.secure);
1067         } else if (value & (1 << 25)) {
1068             armv7m_nvic_clear_pending(s, ARMV7M_EXCP_SYSTICK, attrs.secure);
1069         }
1070         break;
1071     case 0xd08: /* Vector Table Offset.  */
1072         cpu->env.v7m.vecbase[attrs.secure] = value & 0xffffff80;
1073         break;
1074     case 0xd0c: /* Application Interrupt/Reset Control (AIRCR) */
1075         if ((value >> R_V7M_AIRCR_VECTKEY_SHIFT) == 0x05fa) {
1076             if (value & R_V7M_AIRCR_SYSRESETREQ_MASK) {
1077                 if (attrs.secure ||
1078                     !(cpu->env.v7m.aircr & R_V7M_AIRCR_SYSRESETREQS_MASK)) {
1079                     qemu_irq_pulse(s->sysresetreq);
1080                 }
1081             }
1082             if (value & R_V7M_AIRCR_VECTCLRACTIVE_MASK) {
1083                 qemu_log_mask(LOG_GUEST_ERROR,
1084                               "Setting VECTCLRACTIVE when not in DEBUG mode "
1085                               "is UNPREDICTABLE\n");
1086             }
1087             if (value & R_V7M_AIRCR_VECTRESET_MASK) {
1088                 /* NB: this bit is RES0 in v8M */
1089                 qemu_log_mask(LOG_GUEST_ERROR,
1090                               "Setting VECTRESET when not in DEBUG mode "
1091                               "is UNPREDICTABLE\n");
1092             }
1093             s->prigroup[attrs.secure] = extract32(value,
1094                                                   R_V7M_AIRCR_PRIGROUP_SHIFT,
1095                                                   R_V7M_AIRCR_PRIGROUP_LENGTH);
1096             if (attrs.secure) {
1097                 /* These bits are only writable by secure */
1098                 cpu->env.v7m.aircr = value &
1099                     (R_V7M_AIRCR_SYSRESETREQS_MASK |
1100                      R_V7M_AIRCR_BFHFNMINS_MASK |
1101                      R_V7M_AIRCR_PRIS_MASK);
1102                 /* BFHFNMINS changes the priority of Secure HardFault, and
1103                  * allows a pending Non-secure HardFault to preempt (which
1104                  * we implement by marking it enabled).
1105                  */
1106                 if (cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK) {
1107                     s->sec_vectors[ARMV7M_EXCP_HARD].prio = -3;
1108                     s->vectors[ARMV7M_EXCP_HARD].enabled = 1;
1109                 } else {
1110                     s->sec_vectors[ARMV7M_EXCP_HARD].prio = -1;
1111                     s->vectors[ARMV7M_EXCP_HARD].enabled = 0;
1112                 }
1113             }
1114             nvic_irq_update(s);
1115         }
1116         break;
1117     case 0xd10: /* System Control.  */
1118         /* TODO: Implement control registers.  */
1119         qemu_log_mask(LOG_UNIMP, "NVIC: SCR unimplemented\n");
1120         break;
1121     case 0xd14: /* Configuration Control.  */
1122         /* Enforce RAZ/WI on reserved and must-RAZ/WI bits */
1123         value &= (R_V7M_CCR_STKALIGN_MASK |
1124                   R_V7M_CCR_BFHFNMIGN_MASK |
1125                   R_V7M_CCR_DIV_0_TRP_MASK |
1126                   R_V7M_CCR_UNALIGN_TRP_MASK |
1127                   R_V7M_CCR_USERSETMPEND_MASK |
1128                   R_V7M_CCR_NONBASETHRDENA_MASK);
1129 
1130         if (arm_feature(&cpu->env, ARM_FEATURE_V8)) {
1131             /* v8M makes NONBASETHRDENA and STKALIGN be RES1 */
1132             value |= R_V7M_CCR_NONBASETHRDENA_MASK
1133                 | R_V7M_CCR_STKALIGN_MASK;
1134         }
1135         if (attrs.secure) {
1136             /* the BFHFNMIGN bit is not banked; keep that in the NS copy */
1137             cpu->env.v7m.ccr[M_REG_NS] =
1138                 (cpu->env.v7m.ccr[M_REG_NS] & ~R_V7M_CCR_BFHFNMIGN_MASK)
1139                 | (value & R_V7M_CCR_BFHFNMIGN_MASK);
1140             value &= ~R_V7M_CCR_BFHFNMIGN_MASK;
1141         }
1142 
1143         cpu->env.v7m.ccr[attrs.secure] = value;
1144         break;
1145     case 0xd24: /* System Handler Control and State (SHCSR) */
1146         if (attrs.secure) {
1147             s->sec_vectors[ARMV7M_EXCP_MEM].active = (value & (1 << 0)) != 0;
1148             /* Secure HardFault active bit cannot be written */
1149             s->sec_vectors[ARMV7M_EXCP_USAGE].active = (value & (1 << 3)) != 0;
1150             s->sec_vectors[ARMV7M_EXCP_SVC].active = (value & (1 << 7)) != 0;
1151             s->sec_vectors[ARMV7M_EXCP_PENDSV].active =
1152                 (value & (1 << 10)) != 0;
1153             s->sec_vectors[ARMV7M_EXCP_SYSTICK].active =
1154                 (value & (1 << 11)) != 0;
1155             s->sec_vectors[ARMV7M_EXCP_USAGE].pending =
1156                 (value & (1 << 12)) != 0;
1157             s->sec_vectors[ARMV7M_EXCP_MEM].pending = (value & (1 << 13)) != 0;
1158             s->sec_vectors[ARMV7M_EXCP_SVC].pending = (value & (1 << 15)) != 0;
1159             s->sec_vectors[ARMV7M_EXCP_MEM].enabled = (value & (1 << 16)) != 0;
1160             s->sec_vectors[ARMV7M_EXCP_BUS].enabled = (value & (1 << 17)) != 0;
1161             s->sec_vectors[ARMV7M_EXCP_USAGE].enabled =
1162                 (value & (1 << 18)) != 0;
1163             /* SecureFault not banked, but RAZ/WI to NS */
1164             s->vectors[ARMV7M_EXCP_SECURE].active = (value & (1 << 4)) != 0;
1165             s->vectors[ARMV7M_EXCP_SECURE].enabled = (value & (1 << 19)) != 0;
1166             s->vectors[ARMV7M_EXCP_SECURE].pending = (value & (1 << 20)) != 0;
1167         } else {
1168             s->vectors[ARMV7M_EXCP_MEM].active = (value & (1 << 0)) != 0;
1169             if (arm_feature(&cpu->env, ARM_FEATURE_V8)) {
1170                 /* HARDFAULTPENDED is not present in v7M */
1171                 s->vectors[ARMV7M_EXCP_HARD].pending = (value & (1 << 21)) != 0;
1172             }
1173             s->vectors[ARMV7M_EXCP_USAGE].active = (value & (1 << 3)) != 0;
1174             s->vectors[ARMV7M_EXCP_SVC].active = (value & (1 << 7)) != 0;
1175             s->vectors[ARMV7M_EXCP_PENDSV].active = (value & (1 << 10)) != 0;
1176             s->vectors[ARMV7M_EXCP_SYSTICK].active = (value & (1 << 11)) != 0;
1177             s->vectors[ARMV7M_EXCP_USAGE].pending = (value & (1 << 12)) != 0;
1178             s->vectors[ARMV7M_EXCP_MEM].pending = (value & (1 << 13)) != 0;
1179             s->vectors[ARMV7M_EXCP_SVC].pending = (value & (1 << 15)) != 0;
1180             s->vectors[ARMV7M_EXCP_MEM].enabled = (value & (1 << 16)) != 0;
1181             s->vectors[ARMV7M_EXCP_USAGE].enabled = (value & (1 << 18)) != 0;
1182         }
1183         if (attrs.secure || (cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK)) {
1184             s->vectors[ARMV7M_EXCP_BUS].active = (value & (1 << 1)) != 0;
1185             s->vectors[ARMV7M_EXCP_BUS].pending = (value & (1 << 14)) != 0;
1186             s->vectors[ARMV7M_EXCP_BUS].enabled = (value & (1 << 17)) != 0;
1187         }
1188         /* NMIACT can only be written if the write is of a zero, with
1189          * BFHFNMINS 1, and by the CPU in secure state via the NS alias.
1190          */
1191         if (!attrs.secure && cpu->env.v7m.secure &&
1192             (cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK) &&
1193             (value & (1 << 5)) == 0) {
1194             s->vectors[ARMV7M_EXCP_NMI].active = 0;
1195         }
1196         /* HARDFAULTACT can only be written if the write is of a zero
1197          * to the non-secure HardFault state by the CPU in secure state.
1198          * The only case where we can be targeting the non-secure HF state
1199          * when in secure state is if this is a write via the NS alias
1200          * and BFHFNMINS is 1.
1201          */
1202         if (!attrs.secure && cpu->env.v7m.secure &&
1203             (cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK) &&
1204             (value & (1 << 2)) == 0) {
1205             s->vectors[ARMV7M_EXCP_HARD].active = 0;
1206         }
1207 
1208         /* TODO: this is RAZ/WI from NS if DEMCR.SDME is set */
1209         s->vectors[ARMV7M_EXCP_DEBUG].active = (value & (1 << 8)) != 0;
1210         nvic_irq_update(s);
1211         break;
1212     case 0xd28: /* Configurable Fault Status.  */
1213         cpu->env.v7m.cfsr[attrs.secure] &= ~value; /* W1C */
1214         if (attrs.secure) {
1215             /* The BFSR bits [15:8] are shared between security states
1216              * and we store them in the NS copy.
1217              */
1218             cpu->env.v7m.cfsr[M_REG_NS] &= ~(value & R_V7M_CFSR_BFSR_MASK);
1219         }
1220         break;
1221     case 0xd2c: /* Hard Fault Status.  */
1222         cpu->env.v7m.hfsr &= ~value; /* W1C */
1223         break;
1224     case 0xd30: /* Debug Fault Status.  */
1225         cpu->env.v7m.dfsr &= ~value; /* W1C */
1226         break;
1227     case 0xd34: /* Mem Manage Address.  */
1228         cpu->env.v7m.mmfar[attrs.secure] = value;
1229         return;
1230     case 0xd38: /* Bus Fault Address.  */
1231         cpu->env.v7m.bfar = value;
1232         return;
1233     case 0xd3c: /* Aux Fault Status.  */
1234         qemu_log_mask(LOG_UNIMP,
1235                       "NVIC: Aux fault status registers unimplemented\n");
1236         break;
1237     case 0xd90: /* MPU_TYPE */
1238         return; /* RO */
1239     case 0xd94: /* MPU_CTRL */
1240         if ((value &
1241              (R_V7M_MPU_CTRL_HFNMIENA_MASK | R_V7M_MPU_CTRL_ENABLE_MASK))
1242             == R_V7M_MPU_CTRL_HFNMIENA_MASK) {
1243             qemu_log_mask(LOG_GUEST_ERROR, "MPU_CTRL: HFNMIENA and !ENABLE is "
1244                           "UNPREDICTABLE\n");
1245         }
1246         cpu->env.v7m.mpu_ctrl[attrs.secure]
1247             = value & (R_V7M_MPU_CTRL_ENABLE_MASK |
1248                        R_V7M_MPU_CTRL_HFNMIENA_MASK |
1249                        R_V7M_MPU_CTRL_PRIVDEFENA_MASK);
1250         tlb_flush(CPU(cpu));
1251         break;
1252     case 0xd98: /* MPU_RNR */
1253         if (value >= cpu->pmsav7_dregion) {
1254             qemu_log_mask(LOG_GUEST_ERROR, "MPU region out of range %"
1255                           PRIu32 "/%" PRIu32 "\n",
1256                           value, cpu->pmsav7_dregion);
1257         } else {
1258             cpu->env.pmsav7.rnr[attrs.secure] = value;
1259         }
1260         break;
1261     case 0xd9c: /* MPU_RBAR */
1262     case 0xda4: /* MPU_RBAR_A1 */
1263     case 0xdac: /* MPU_RBAR_A2 */
1264     case 0xdb4: /* MPU_RBAR_A3 */
1265     {
1266         int region;
1267 
1268         if (arm_feature(&cpu->env, ARM_FEATURE_V8)) {
1269             /* PMSAv8M handling of the aliases is different from v7M:
1270              * aliases A1, A2, A3 override the low two bits of the region
1271              * number in MPU_RNR, and there is no 'region' field in the
1272              * RBAR register.
1273              */
1274             int aliasno = (offset - 0xd9c) / 8; /* 0..3 */
1275 
1276             region = cpu->env.pmsav7.rnr[attrs.secure];
1277             if (aliasno) {
1278                 region = deposit32(region, 0, 2, aliasno);
1279             }
1280             if (region >= cpu->pmsav7_dregion) {
1281                 return;
1282             }
1283             cpu->env.pmsav8.rbar[attrs.secure][region] = value;
1284             tlb_flush(CPU(cpu));
1285             return;
1286         }
1287 
1288         if (value & (1 << 4)) {
1289             /* VALID bit means use the region number specified in this
1290              * value and also update MPU_RNR.REGION with that value.
1291              */
1292             region = extract32(value, 0, 4);
1293             if (region >= cpu->pmsav7_dregion) {
1294                 qemu_log_mask(LOG_GUEST_ERROR,
1295                               "MPU region out of range %u/%" PRIu32 "\n",
1296                               region, cpu->pmsav7_dregion);
1297                 return;
1298             }
1299             cpu->env.pmsav7.rnr[attrs.secure] = region;
1300         } else {
1301             region = cpu->env.pmsav7.rnr[attrs.secure];
1302         }
1303 
1304         if (region >= cpu->pmsav7_dregion) {
1305             return;
1306         }
1307 
1308         cpu->env.pmsav7.drbar[region] = value & ~0x1f;
1309         tlb_flush(CPU(cpu));
1310         break;
1311     }
1312     case 0xda0: /* MPU_RASR (v7M), MPU_RLAR (v8M) */
1313     case 0xda8: /* MPU_RASR_A1 (v7M), MPU_RLAR_A1 (v8M) */
1314     case 0xdb0: /* MPU_RASR_A2 (v7M), MPU_RLAR_A2 (v8M) */
1315     case 0xdb8: /* MPU_RASR_A3 (v7M), MPU_RLAR_A3 (v8M) */
1316     {
1317         int region = cpu->env.pmsav7.rnr[attrs.secure];
1318 
1319         if (arm_feature(&cpu->env, ARM_FEATURE_V8)) {
1320             /* PMSAv8M handling of the aliases is different from v7M:
1321              * aliases A1, A2, A3 override the low two bits of the region
1322              * number in MPU_RNR.
1323              */
1324             int aliasno = (offset - 0xd9c) / 8; /* 0..3 */
1325 
1326             region = cpu->env.pmsav7.rnr[attrs.secure];
1327             if (aliasno) {
1328                 region = deposit32(region, 0, 2, aliasno);
1329             }
1330             if (region >= cpu->pmsav7_dregion) {
1331                 return;
1332             }
1333             cpu->env.pmsav8.rlar[attrs.secure][region] = value;
1334             tlb_flush(CPU(cpu));
1335             return;
1336         }
1337 
1338         if (region >= cpu->pmsav7_dregion) {
1339             return;
1340         }
1341 
1342         cpu->env.pmsav7.drsr[region] = value & 0xff3f;
1343         cpu->env.pmsav7.dracr[region] = (value >> 16) & 0x173f;
1344         tlb_flush(CPU(cpu));
1345         break;
1346     }
1347     case 0xdc0: /* MPU_MAIR0 */
1348         if (!arm_feature(&cpu->env, ARM_FEATURE_V8)) {
1349             goto bad_offset;
1350         }
1351         if (cpu->pmsav7_dregion) {
1352             /* Register is RES0 if no MPU regions are implemented */
1353             cpu->env.pmsav8.mair0[attrs.secure] = value;
1354         }
1355         /* We don't need to do anything else because memory attributes
1356          * only affect cacheability, and we don't implement caching.
1357          */
1358         break;
1359     case 0xdc4: /* MPU_MAIR1 */
1360         if (!arm_feature(&cpu->env, ARM_FEATURE_V8)) {
1361             goto bad_offset;
1362         }
1363         if (cpu->pmsav7_dregion) {
1364             /* Register is RES0 if no MPU regions are implemented */
1365             cpu->env.pmsav8.mair1[attrs.secure] = value;
1366         }
1367         /* We don't need to do anything else because memory attributes
1368          * only affect cacheability, and we don't implement caching.
1369          */
1370         break;
1371     case 0xf00: /* Software Triggered Interrupt Register */
1372     {
1373         int excnum = (value & 0x1ff) + NVIC_FIRST_IRQ;
1374         if (excnum < s->num_irq) {
1375             armv7m_nvic_set_pending(s, excnum, false);
1376         }
1377         break;
1378     }
1379     default:
1380     bad_offset:
1381         qemu_log_mask(LOG_GUEST_ERROR,
1382                       "NVIC: Bad write offset 0x%x\n", offset);
1383     }
1384 }
1385 
1386 static bool nvic_user_access_ok(NVICState *s, hwaddr offset, MemTxAttrs attrs)
1387 {
1388     /* Return true if unprivileged access to this register is permitted. */
1389     switch (offset) {
1390     case 0xf00: /* STIR: accessible only if CCR.USERSETMPEND permits */
1391         /* For access via STIR_NS it is the NS CCR.USERSETMPEND that
1392          * controls access even though the CPU is in Secure state (I_QDKX).
1393          */
1394         return s->cpu->env.v7m.ccr[attrs.secure] & R_V7M_CCR_USERSETMPEND_MASK;
1395     default:
1396         /* All other user accesses cause a BusFault unconditionally */
1397         return false;
1398     }
1399 }
1400 
1401 static int shpr_bank(NVICState *s, int exc, MemTxAttrs attrs)
1402 {
1403     /* Behaviour for the SHPR register field for this exception:
1404      * return M_REG_NS to use the nonsecure vector (including for
1405      * non-banked exceptions), M_REG_S for the secure version of
1406      * a banked exception, and -1 if this field should RAZ/WI.
1407      */
1408     switch (exc) {
1409     case ARMV7M_EXCP_MEM:
1410     case ARMV7M_EXCP_USAGE:
1411     case ARMV7M_EXCP_SVC:
1412     case ARMV7M_EXCP_PENDSV:
1413     case ARMV7M_EXCP_SYSTICK:
1414         /* Banked exceptions */
1415         return attrs.secure;
1416     case ARMV7M_EXCP_BUS:
1417         /* Not banked, RAZ/WI from nonsecure if BFHFNMINS is zero */
1418         if (!attrs.secure &&
1419             !(s->cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK)) {
1420             return -1;
1421         }
1422         return M_REG_NS;
1423     case ARMV7M_EXCP_SECURE:
1424         /* Not banked, RAZ/WI from nonsecure */
1425         if (!attrs.secure) {
1426             return -1;
1427         }
1428         return M_REG_NS;
1429     case ARMV7M_EXCP_DEBUG:
1430         /* Not banked. TODO should RAZ/WI if DEMCR.SDME is set */
1431         return M_REG_NS;
1432     case 8 ... 10:
1433     case 13:
1434         /* RES0 */
1435         return -1;
1436     default:
1437         /* Not reachable due to decode of SHPR register addresses */
1438         g_assert_not_reached();
1439     }
1440 }
1441 
1442 static MemTxResult nvic_sysreg_read(void *opaque, hwaddr addr,
1443                                     uint64_t *data, unsigned size,
1444                                     MemTxAttrs attrs)
1445 {
1446     NVICState *s = (NVICState *)opaque;
1447     uint32_t offset = addr;
1448     unsigned i, startvec, end;
1449     uint32_t val;
1450 
1451     if (attrs.user && !nvic_user_access_ok(s, addr, attrs)) {
1452         /* Generate BusFault for unprivileged accesses */
1453         return MEMTX_ERROR;
1454     }
1455 
1456     switch (offset) {
1457     /* reads of set and clear both return the status */
1458     case 0x100 ... 0x13f: /* NVIC Set enable */
1459         offset += 0x80;
1460         /* fall through */
1461     case 0x180 ... 0x1bf: /* NVIC Clear enable */
1462         val = 0;
1463         startvec = offset - 0x180 + NVIC_FIRST_IRQ; /* vector # */
1464 
1465         for (i = 0, end = size * 8; i < end && startvec + i < s->num_irq; i++) {
1466             if (s->vectors[startvec + i].enabled &&
1467                 (attrs.secure || s->itns[startvec + i])) {
1468                 val |= (1 << i);
1469             }
1470         }
1471         break;
1472     case 0x200 ... 0x23f: /* NVIC Set pend */
1473         offset += 0x80;
1474         /* fall through */
1475     case 0x280 ... 0x2bf: /* NVIC Clear pend */
1476         val = 0;
1477         startvec = offset - 0x280 + NVIC_FIRST_IRQ; /* vector # */
1478         for (i = 0, end = size * 8; i < end && startvec + i < s->num_irq; i++) {
1479             if (s->vectors[startvec + i].pending &&
1480                 (attrs.secure || s->itns[startvec + i])) {
1481                 val |= (1 << i);
1482             }
1483         }
1484         break;
1485     case 0x300 ... 0x33f: /* NVIC Active */
1486         val = 0;
1487         startvec = offset - 0x300 + NVIC_FIRST_IRQ; /* vector # */
1488 
1489         for (i = 0, end = size * 8; i < end && startvec + i < s->num_irq; i++) {
1490             if (s->vectors[startvec + i].active &&
1491                 (attrs.secure || s->itns[startvec + i])) {
1492                 val |= (1 << i);
1493             }
1494         }
1495         break;
1496     case 0x400 ... 0x5ef: /* NVIC Priority */
1497         val = 0;
1498         startvec = offset - 0x400 + NVIC_FIRST_IRQ; /* vector # */
1499 
1500         for (i = 0; i < size && startvec + i < s->num_irq; i++) {
1501             if (attrs.secure || s->itns[startvec + i]) {
1502                 val |= s->vectors[startvec + i].prio << (8 * i);
1503             }
1504         }
1505         break;
1506     case 0xd18 ... 0xd23: /* System Handler Priority (SHPR1, SHPR2, SHPR3) */
1507         val = 0;
1508         for (i = 0; i < size; i++) {
1509             unsigned hdlidx = (offset - 0xd14) + i;
1510             int sbank = shpr_bank(s, hdlidx, attrs);
1511 
1512             if (sbank < 0) {
1513                 continue;
1514             }
1515             val = deposit32(val, i * 8, 8, get_prio(s, hdlidx, sbank));
1516         }
1517         break;
1518     case 0xfe0 ... 0xfff: /* ID.  */
1519         if (offset & 3) {
1520             val = 0;
1521         } else {
1522             val = nvic_id[(offset - 0xfe0) >> 2];
1523         }
1524         break;
1525     default:
1526         if (size == 4) {
1527             val = nvic_readl(s, offset, attrs);
1528         } else {
1529             qemu_log_mask(LOG_GUEST_ERROR,
1530                           "NVIC: Bad read of size %d at offset 0x%x\n",
1531                           size, offset);
1532             val = 0;
1533         }
1534     }
1535 
1536     trace_nvic_sysreg_read(addr, val, size);
1537     *data = val;
1538     return MEMTX_OK;
1539 }
1540 
1541 static MemTxResult nvic_sysreg_write(void *opaque, hwaddr addr,
1542                                      uint64_t value, unsigned size,
1543                                      MemTxAttrs attrs)
1544 {
1545     NVICState *s = (NVICState *)opaque;
1546     uint32_t offset = addr;
1547     unsigned i, startvec, end;
1548     unsigned setval = 0;
1549 
1550     trace_nvic_sysreg_write(addr, value, size);
1551 
1552     if (attrs.user && !nvic_user_access_ok(s, addr, attrs)) {
1553         /* Generate BusFault for unprivileged accesses */
1554         return MEMTX_ERROR;
1555     }
1556 
1557     switch (offset) {
1558     case 0x100 ... 0x13f: /* NVIC Set enable */
1559         offset += 0x80;
1560         setval = 1;
1561         /* fall through */
1562     case 0x180 ... 0x1bf: /* NVIC Clear enable */
1563         startvec = 8 * (offset - 0x180) + NVIC_FIRST_IRQ;
1564 
1565         for (i = 0, end = size * 8; i < end && startvec + i < s->num_irq; i++) {
1566             if (value & (1 << i) &&
1567                 (attrs.secure || s->itns[startvec + i])) {
1568                 s->vectors[startvec + i].enabled = setval;
1569             }
1570         }
1571         nvic_irq_update(s);
1572         return MEMTX_OK;
1573     case 0x200 ... 0x23f: /* NVIC Set pend */
1574         /* the special logic in armv7m_nvic_set_pending()
1575          * is not needed since IRQs are never escalated
1576          */
1577         offset += 0x80;
1578         setval = 1;
1579         /* fall through */
1580     case 0x280 ... 0x2bf: /* NVIC Clear pend */
1581         startvec = 8 * (offset - 0x280) + NVIC_FIRST_IRQ; /* vector # */
1582 
1583         for (i = 0, end = size * 8; i < end && startvec + i < s->num_irq; i++) {
1584             if (value & (1 << i) &&
1585                 (attrs.secure || s->itns[startvec + i])) {
1586                 s->vectors[startvec + i].pending = setval;
1587             }
1588         }
1589         nvic_irq_update(s);
1590         return MEMTX_OK;
1591     case 0x300 ... 0x33f: /* NVIC Active */
1592         return MEMTX_OK; /* R/O */
1593     case 0x400 ... 0x5ef: /* NVIC Priority */
1594         startvec = 8 * (offset - 0x400) + NVIC_FIRST_IRQ; /* vector # */
1595 
1596         for (i = 0; i < size && startvec + i < s->num_irq; i++) {
1597             if (attrs.secure || s->itns[startvec + i]) {
1598                 set_prio(s, startvec + i, false, (value >> (i * 8)) & 0xff);
1599             }
1600         }
1601         nvic_irq_update(s);
1602         return MEMTX_OK;
1603     case 0xd18 ... 0xd23: /* System Handler Priority (SHPR1, SHPR2, SHPR3) */
1604         for (i = 0; i < size; i++) {
1605             unsigned hdlidx = (offset - 0xd14) + i;
1606             int newprio = extract32(value, i * 8, 8);
1607             int sbank = shpr_bank(s, hdlidx, attrs);
1608 
1609             if (sbank < 0) {
1610                 continue;
1611             }
1612             set_prio(s, hdlidx, sbank, newprio);
1613         }
1614         nvic_irq_update(s);
1615         return MEMTX_OK;
1616     }
1617     if (size == 4) {
1618         nvic_writel(s, offset, value, attrs);
1619         return MEMTX_OK;
1620     }
1621     qemu_log_mask(LOG_GUEST_ERROR,
1622                   "NVIC: Bad write of size %d at offset 0x%x\n", size, offset);
1623     /* This is UNPREDICTABLE; treat as RAZ/WI */
1624     return MEMTX_OK;
1625 }
1626 
1627 static const MemoryRegionOps nvic_sysreg_ops = {
1628     .read_with_attrs = nvic_sysreg_read,
1629     .write_with_attrs = nvic_sysreg_write,
1630     .endianness = DEVICE_NATIVE_ENDIAN,
1631 };
1632 
1633 static MemTxResult nvic_sysreg_ns_write(void *opaque, hwaddr addr,
1634                                         uint64_t value, unsigned size,
1635                                         MemTxAttrs attrs)
1636 {
1637     if (attrs.secure) {
1638         /* S accesses to the alias act like NS accesses to the real region */
1639         attrs.secure = 0;
1640         return nvic_sysreg_write(opaque, addr, value, size, attrs);
1641     } else {
1642         /* NS attrs are RAZ/WI for privileged, and BusFault for user */
1643         if (attrs.user) {
1644             return MEMTX_ERROR;
1645         }
1646         return MEMTX_OK;
1647     }
1648 }
1649 
1650 static MemTxResult nvic_sysreg_ns_read(void *opaque, hwaddr addr,
1651                                        uint64_t *data, unsigned size,
1652                                        MemTxAttrs attrs)
1653 {
1654     if (attrs.secure) {
1655         /* S accesses to the alias act like NS accesses to the real region */
1656         attrs.secure = 0;
1657         return nvic_sysreg_read(opaque, addr, data, size, attrs);
1658     } else {
1659         /* NS attrs are RAZ/WI for privileged, and BusFault for user */
1660         if (attrs.user) {
1661             return MEMTX_ERROR;
1662         }
1663         *data = 0;
1664         return MEMTX_OK;
1665     }
1666 }
1667 
1668 static const MemoryRegionOps nvic_sysreg_ns_ops = {
1669     .read_with_attrs = nvic_sysreg_ns_read,
1670     .write_with_attrs = nvic_sysreg_ns_write,
1671     .endianness = DEVICE_NATIVE_ENDIAN,
1672 };
1673 
1674 static int nvic_post_load(void *opaque, int version_id)
1675 {
1676     NVICState *s = opaque;
1677     unsigned i;
1678     int resetprio;
1679 
1680     /* Check for out of range priority settings */
1681     resetprio = arm_feature(&s->cpu->env, ARM_FEATURE_V8) ? -4 : -3;
1682 
1683     if (s->vectors[ARMV7M_EXCP_RESET].prio != resetprio ||
1684         s->vectors[ARMV7M_EXCP_NMI].prio != -2 ||
1685         s->vectors[ARMV7M_EXCP_HARD].prio != -1) {
1686         return 1;
1687     }
1688     for (i = ARMV7M_EXCP_MEM; i < s->num_irq; i++) {
1689         if (s->vectors[i].prio & ~0xff) {
1690             return 1;
1691         }
1692     }
1693 
1694     nvic_recompute_state(s);
1695 
1696     return 0;
1697 }
1698 
1699 static const VMStateDescription vmstate_VecInfo = {
1700     .name = "armv7m_nvic_info",
1701     .version_id = 1,
1702     .minimum_version_id = 1,
1703     .fields = (VMStateField[]) {
1704         VMSTATE_INT16(prio, VecInfo),
1705         VMSTATE_UINT8(enabled, VecInfo),
1706         VMSTATE_UINT8(pending, VecInfo),
1707         VMSTATE_UINT8(active, VecInfo),
1708         VMSTATE_UINT8(level, VecInfo),
1709         VMSTATE_END_OF_LIST()
1710     }
1711 };
1712 
1713 static bool nvic_security_needed(void *opaque)
1714 {
1715     NVICState *s = opaque;
1716 
1717     return arm_feature(&s->cpu->env, ARM_FEATURE_M_SECURITY);
1718 }
1719 
1720 static int nvic_security_post_load(void *opaque, int version_id)
1721 {
1722     NVICState *s = opaque;
1723     int i;
1724 
1725     /* Check for out of range priority settings */
1726     if (s->sec_vectors[ARMV7M_EXCP_HARD].prio != -1
1727         && s->sec_vectors[ARMV7M_EXCP_HARD].prio != -3) {
1728         /* We can't cross-check against AIRCR.BFHFNMINS as we don't know
1729          * if the CPU state has been migrated yet; a mismatch won't
1730          * cause the emulation to blow up, though.
1731          */
1732         return 1;
1733     }
1734     for (i = ARMV7M_EXCP_MEM; i < ARRAY_SIZE(s->sec_vectors); i++) {
1735         if (s->sec_vectors[i].prio & ~0xff) {
1736             return 1;
1737         }
1738     }
1739     return 0;
1740 }
1741 
1742 static const VMStateDescription vmstate_nvic_security = {
1743     .name = "nvic/m-security",
1744     .version_id = 1,
1745     .minimum_version_id = 1,
1746     .needed = nvic_security_needed,
1747     .post_load = &nvic_security_post_load,
1748     .fields = (VMStateField[]) {
1749         VMSTATE_STRUCT_ARRAY(sec_vectors, NVICState, NVIC_INTERNAL_VECTORS, 1,
1750                              vmstate_VecInfo, VecInfo),
1751         VMSTATE_UINT32(prigroup[M_REG_S], NVICState),
1752         VMSTATE_BOOL_ARRAY(itns, NVICState, NVIC_MAX_VECTORS),
1753         VMSTATE_END_OF_LIST()
1754     }
1755 };
1756 
1757 static const VMStateDescription vmstate_nvic = {
1758     .name = "armv7m_nvic",
1759     .version_id = 4,
1760     .minimum_version_id = 4,
1761     .post_load = &nvic_post_load,
1762     .fields = (VMStateField[]) {
1763         VMSTATE_STRUCT_ARRAY(vectors, NVICState, NVIC_MAX_VECTORS, 1,
1764                              vmstate_VecInfo, VecInfo),
1765         VMSTATE_UINT32(prigroup[M_REG_NS], NVICState),
1766         VMSTATE_END_OF_LIST()
1767     },
1768     .subsections = (const VMStateDescription*[]) {
1769         &vmstate_nvic_security,
1770         NULL
1771     }
1772 };
1773 
1774 static Property props_nvic[] = {
1775     /* Number of external IRQ lines (so excluding the 16 internal exceptions) */
1776     DEFINE_PROP_UINT32("num-irq", NVICState, num_irq, 64),
1777     DEFINE_PROP_END_OF_LIST()
1778 };
1779 
1780 static void armv7m_nvic_reset(DeviceState *dev)
1781 {
1782     int resetprio;
1783     NVICState *s = NVIC(dev);
1784 
1785     s->vectors[ARMV7M_EXCP_NMI].enabled = 1;
1786     /* MEM, BUS, and USAGE are enabled through
1787      * the System Handler Control register
1788      */
1789     s->vectors[ARMV7M_EXCP_SVC].enabled = 1;
1790     s->vectors[ARMV7M_EXCP_DEBUG].enabled = 1;
1791     s->vectors[ARMV7M_EXCP_PENDSV].enabled = 1;
1792     s->vectors[ARMV7M_EXCP_SYSTICK].enabled = 1;
1793 
1794     resetprio = arm_feature(&s->cpu->env, ARM_FEATURE_V8) ? -4 : -3;
1795     s->vectors[ARMV7M_EXCP_RESET].prio = resetprio;
1796     s->vectors[ARMV7M_EXCP_NMI].prio = -2;
1797     s->vectors[ARMV7M_EXCP_HARD].prio = -1;
1798 
1799     if (arm_feature(&s->cpu->env, ARM_FEATURE_M_SECURITY)) {
1800         s->sec_vectors[ARMV7M_EXCP_HARD].enabled = 1;
1801         s->sec_vectors[ARMV7M_EXCP_SVC].enabled = 1;
1802         s->sec_vectors[ARMV7M_EXCP_PENDSV].enabled = 1;
1803         s->sec_vectors[ARMV7M_EXCP_SYSTICK].enabled = 1;
1804 
1805         /* AIRCR.BFHFNMINS resets to 0 so Secure HF is priority -1 (R_CMTC) */
1806         s->sec_vectors[ARMV7M_EXCP_HARD].prio = -1;
1807         /* If AIRCR.BFHFNMINS is 0 then NS HF is (effectively) disabled */
1808         s->vectors[ARMV7M_EXCP_HARD].enabled = 0;
1809     } else {
1810         s->vectors[ARMV7M_EXCP_HARD].enabled = 1;
1811     }
1812 
1813     /* Strictly speaking the reset handler should be enabled.
1814      * However, we don't simulate soft resets through the NVIC,
1815      * and the reset vector should never be pended.
1816      * So we leave it disabled to catch logic errors.
1817      */
1818 
1819     s->exception_prio = NVIC_NOEXC_PRIO;
1820     s->vectpending = 0;
1821     s->vectpending_is_s_banked = false;
1822     s->vectpending_prio = NVIC_NOEXC_PRIO;
1823 
1824     if (arm_feature(&s->cpu->env, ARM_FEATURE_M_SECURITY)) {
1825         memset(s->itns, 0, sizeof(s->itns));
1826     } else {
1827         /* This state is constant and not guest accessible in a non-security
1828          * NVIC; we set the bits to true to avoid having to do a feature
1829          * bit check in the NVIC enable/pend/etc register accessors.
1830          */
1831         int i;
1832 
1833         for (i = NVIC_FIRST_IRQ; i < ARRAY_SIZE(s->itns); i++) {
1834             s->itns[i] = true;
1835         }
1836     }
1837 }
1838 
1839 static void nvic_systick_trigger(void *opaque, int n, int level)
1840 {
1841     NVICState *s = opaque;
1842 
1843     if (level) {
1844         /* SysTick just asked us to pend its exception.
1845          * (This is different from an external interrupt line's
1846          * behaviour.)
1847          * TODO: when we implement the banked systicks we must make
1848          * this pend the correct banked exception.
1849          */
1850         armv7m_nvic_set_pending(s, ARMV7M_EXCP_SYSTICK, false);
1851     }
1852 }
1853 
1854 static void armv7m_nvic_realize(DeviceState *dev, Error **errp)
1855 {
1856     NVICState *s = NVIC(dev);
1857     SysBusDevice *systick_sbd;
1858     Error *err = NULL;
1859     int regionlen;
1860 
1861     s->cpu = ARM_CPU(qemu_get_cpu(0));
1862     assert(s->cpu);
1863 
1864     if (s->num_irq > NVIC_MAX_IRQ) {
1865         error_setg(errp, "num-irq %d exceeds NVIC maximum", s->num_irq);
1866         return;
1867     }
1868 
1869     qdev_init_gpio_in(dev, set_irq_level, s->num_irq);
1870 
1871     /* include space for internal exception vectors */
1872     s->num_irq += NVIC_FIRST_IRQ;
1873 
1874     object_property_set_bool(OBJECT(&s->systick), true, "realized", &err);
1875     if (err != NULL) {
1876         error_propagate(errp, err);
1877         return;
1878     }
1879     systick_sbd = SYS_BUS_DEVICE(&s->systick);
1880     sysbus_connect_irq(systick_sbd, 0,
1881                        qdev_get_gpio_in_named(dev, "systick-trigger", 0));
1882 
1883     /* The NVIC and System Control Space (SCS) starts at 0xe000e000
1884      * and looks like this:
1885      *  0x004 - ICTR
1886      *  0x010 - 0xff - systick
1887      *  0x100..0x7ec - NVIC
1888      *  0x7f0..0xcff - Reserved
1889      *  0xd00..0xd3c - SCS registers
1890      *  0xd40..0xeff - Reserved or Not implemented
1891      *  0xf00 - STIR
1892      *
1893      * Some registers within this space are banked between security states.
1894      * In v8M there is a second range 0xe002e000..0xe002efff which is the
1895      * NonSecure alias SCS; secure accesses to this behave like NS accesses
1896      * to the main SCS range, and non-secure accesses (including when
1897      * the security extension is not implemented) are RAZ/WI.
1898      * Note that both the main SCS range and the alias range are defined
1899      * to be exempt from memory attribution (R_BLJT) and so the memory
1900      * transaction attribute always matches the current CPU security
1901      * state (attrs.secure == env->v7m.secure). In the nvic_sysreg_ns_ops
1902      * wrappers we change attrs.secure to indicate the NS access; so
1903      * generally code determining which banked register to use should
1904      * use attrs.secure; code determining actual behaviour of the system
1905      * should use env->v7m.secure.
1906      */
1907     regionlen = arm_feature(&s->cpu->env, ARM_FEATURE_V8) ? 0x21000 : 0x1000;
1908     memory_region_init(&s->container, OBJECT(s), "nvic", regionlen);
1909     /* The system register region goes at the bottom of the priority
1910      * stack as it covers the whole page.
1911      */
1912     memory_region_init_io(&s->sysregmem, OBJECT(s), &nvic_sysreg_ops, s,
1913                           "nvic_sysregs", 0x1000);
1914     memory_region_add_subregion(&s->container, 0, &s->sysregmem);
1915     memory_region_add_subregion_overlap(&s->container, 0x10,
1916                                         sysbus_mmio_get_region(systick_sbd, 0),
1917                                         1);
1918 
1919     if (arm_feature(&s->cpu->env, ARM_FEATURE_V8)) {
1920         memory_region_init_io(&s->sysreg_ns_mem, OBJECT(s),
1921                               &nvic_sysreg_ns_ops, s,
1922                               "nvic_sysregs_ns", 0x1000);
1923         memory_region_add_subregion(&s->container, 0x20000, &s->sysreg_ns_mem);
1924     }
1925 
1926     sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->container);
1927 }
1928 
1929 static void armv7m_nvic_instance_init(Object *obj)
1930 {
1931     /* We have a different default value for the num-irq property
1932      * than our superclass. This function runs after qdev init
1933      * has set the defaults from the Property array and before
1934      * any user-specified property setting, so just modify the
1935      * value in the GICState struct.
1936      */
1937     DeviceState *dev = DEVICE(obj);
1938     NVICState *nvic = NVIC(obj);
1939     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
1940 
1941     object_initialize(&nvic->systick, sizeof(nvic->systick), TYPE_SYSTICK);
1942     qdev_set_parent_bus(DEVICE(&nvic->systick), sysbus_get_default());
1943 
1944     sysbus_init_irq(sbd, &nvic->excpout);
1945     qdev_init_gpio_out_named(dev, &nvic->sysresetreq, "SYSRESETREQ", 1);
1946     qdev_init_gpio_in_named(dev, nvic_systick_trigger, "systick-trigger", 1);
1947 }
1948 
1949 static void armv7m_nvic_class_init(ObjectClass *klass, void *data)
1950 {
1951     DeviceClass *dc = DEVICE_CLASS(klass);
1952 
1953     dc->vmsd  = &vmstate_nvic;
1954     dc->props = props_nvic;
1955     dc->reset = armv7m_nvic_reset;
1956     dc->realize = armv7m_nvic_realize;
1957 }
1958 
1959 static const TypeInfo armv7m_nvic_info = {
1960     .name          = TYPE_NVIC,
1961     .parent        = TYPE_SYS_BUS_DEVICE,
1962     .instance_init = armv7m_nvic_instance_init,
1963     .instance_size = sizeof(NVICState),
1964     .class_init    = armv7m_nvic_class_init,
1965     .class_size    = sizeof(SysBusDeviceClass),
1966 };
1967 
1968 static void armv7m_nvic_register_types(void)
1969 {
1970     type_register_static(&armv7m_nvic_info);
1971 }
1972 
1973 type_init(armv7m_nvic_register_types)
1974