xref: /openbmc/qemu/hw/intc/armv7m_nvic.c (revision 437d59c17e96976a567ad1547e272cdfe4a5f1d7)
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 void 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 
597     assert(pending > ARMV7M_EXCP_RESET && pending < s->num_irq);
598 
599     vec = &s->vectors[pending];
600 
601     assert(vec->enabled);
602     assert(vec->pending);
603 
604     assert(s->vectpending_prio < running);
605 
606     trace_nvic_acknowledge_irq(pending, s->vectpending_prio);
607 
608     vec->active = 1;
609     vec->pending = 0;
610 
611     env->v7m.exception = s->vectpending;
612 
613     nvic_irq_update(s);
614 }
615 
616 int armv7m_nvic_complete_irq(void *opaque, int irq)
617 {
618     NVICState *s = (NVICState *)opaque;
619     VecInfo *vec;
620     int ret;
621 
622     assert(irq > ARMV7M_EXCP_RESET && irq < s->num_irq);
623 
624     vec = &s->vectors[irq];
625 
626     trace_nvic_complete_irq(irq);
627 
628     if (!vec->active) {
629         /* Tell the caller this was an illegal exception return */
630         return -1;
631     }
632 
633     ret = nvic_rettobase(s);
634 
635     vec->active = 0;
636     if (vec->level) {
637         /* Re-pend the exception if it's still held high; only
638          * happens for extenal IRQs
639          */
640         assert(irq >= NVIC_FIRST_IRQ);
641         vec->pending = 1;
642     }
643 
644     nvic_irq_update(s);
645 
646     return ret;
647 }
648 
649 /* callback when external interrupt line is changed */
650 static void set_irq_level(void *opaque, int n, int level)
651 {
652     NVICState *s = opaque;
653     VecInfo *vec;
654 
655     n += NVIC_FIRST_IRQ;
656 
657     assert(n >= NVIC_FIRST_IRQ && n < s->num_irq);
658 
659     trace_nvic_set_irq_level(n, level);
660 
661     /* The pending status of an external interrupt is
662      * latched on rising edge and exception handler return.
663      *
664      * Pulsing the IRQ will always run the handler
665      * once, and the handler will re-run until the
666      * level is low when the handler completes.
667      */
668     vec = &s->vectors[n];
669     if (level != vec->level) {
670         vec->level = level;
671         if (level) {
672             armv7m_nvic_set_pending(s, n, false);
673         }
674     }
675 }
676 
677 static uint32_t nvic_readl(NVICState *s, uint32_t offset, MemTxAttrs attrs)
678 {
679     ARMCPU *cpu = s->cpu;
680     uint32_t val;
681 
682     switch (offset) {
683     case 4: /* Interrupt Control Type.  */
684         return ((s->num_irq - NVIC_FIRST_IRQ) / 32) - 1;
685     case 0x380 ... 0x3bf: /* NVIC_ITNS<n> */
686     {
687         int startvec = 32 * (offset - 0x380) + NVIC_FIRST_IRQ;
688         int i;
689 
690         if (!arm_feature(&cpu->env, ARM_FEATURE_V8)) {
691             goto bad_offset;
692         }
693         if (!attrs.secure) {
694             return 0;
695         }
696         val = 0;
697         for (i = 0; i < 32 && startvec + i < s->num_irq; i++) {
698             if (s->itns[startvec + i]) {
699                 val |= (1 << i);
700             }
701         }
702         return val;
703     }
704     case 0xd00: /* CPUID Base.  */
705         return cpu->midr;
706     case 0xd04: /* Interrupt Control State (ICSR) */
707         /* VECTACTIVE */
708         val = cpu->env.v7m.exception;
709         /* VECTPENDING */
710         val |= (s->vectpending & 0xff) << 12;
711         /* ISRPENDING - set if any external IRQ is pending */
712         if (nvic_isrpending(s)) {
713             val |= (1 << 22);
714         }
715         /* RETTOBASE - set if only one handler is active */
716         if (nvic_rettobase(s)) {
717             val |= (1 << 11);
718         }
719         if (attrs.secure) {
720             /* PENDSTSET */
721             if (s->sec_vectors[ARMV7M_EXCP_SYSTICK].pending) {
722                 val |= (1 << 26);
723             }
724             /* PENDSVSET */
725             if (s->sec_vectors[ARMV7M_EXCP_PENDSV].pending) {
726                 val |= (1 << 28);
727             }
728         } else {
729             /* PENDSTSET */
730             if (s->vectors[ARMV7M_EXCP_SYSTICK].pending) {
731                 val |= (1 << 26);
732             }
733             /* PENDSVSET */
734             if (s->vectors[ARMV7M_EXCP_PENDSV].pending) {
735                 val |= (1 << 28);
736             }
737         }
738         /* NMIPENDSET */
739         if ((cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK) &&
740             s->vectors[ARMV7M_EXCP_NMI].pending) {
741             val |= (1 << 31);
742         }
743         /* ISRPREEMPT: RES0 when halting debug not implemented */
744         /* STTNS: RES0 for the Main Extension */
745         return val;
746     case 0xd08: /* Vector Table Offset.  */
747         return cpu->env.v7m.vecbase[attrs.secure];
748     case 0xd0c: /* Application Interrupt/Reset Control (AIRCR) */
749         val = 0xfa050000 | (s->prigroup[attrs.secure] << 8);
750         if (attrs.secure) {
751             /* s->aircr stores PRIS, BFHFNMINS, SYSRESETREQS */
752             val |= cpu->env.v7m.aircr;
753         } else {
754             if (arm_feature(&cpu->env, ARM_FEATURE_V8)) {
755                 /* BFHFNMINS is R/O from NS; other bits are RAZ/WI. If
756                  * security isn't supported then BFHFNMINS is RAO (and
757                  * the bit in env.v7m.aircr is always set).
758                  */
759                 val |= cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK;
760             }
761         }
762         return val;
763     case 0xd10: /* System Control.  */
764         /* TODO: Implement SLEEPONEXIT.  */
765         return 0;
766     case 0xd14: /* Configuration Control.  */
767         /* The BFHFNMIGN bit is the only non-banked bit; we
768          * keep it in the non-secure copy of the register.
769          */
770         val = cpu->env.v7m.ccr[attrs.secure];
771         val |= cpu->env.v7m.ccr[M_REG_NS] & R_V7M_CCR_BFHFNMIGN_MASK;
772         return val;
773     case 0xd24: /* System Handler Control and State (SHCSR) */
774         val = 0;
775         if (attrs.secure) {
776             if (s->sec_vectors[ARMV7M_EXCP_MEM].active) {
777                 val |= (1 << 0);
778             }
779             if (s->sec_vectors[ARMV7M_EXCP_HARD].active) {
780                 val |= (1 << 2);
781             }
782             if (s->sec_vectors[ARMV7M_EXCP_USAGE].active) {
783                 val |= (1 << 3);
784             }
785             if (s->sec_vectors[ARMV7M_EXCP_SVC].active) {
786                 val |= (1 << 7);
787             }
788             if (s->sec_vectors[ARMV7M_EXCP_PENDSV].active) {
789                 val |= (1 << 10);
790             }
791             if (s->sec_vectors[ARMV7M_EXCP_SYSTICK].active) {
792                 val |= (1 << 11);
793             }
794             if (s->sec_vectors[ARMV7M_EXCP_USAGE].pending) {
795                 val |= (1 << 12);
796             }
797             if (s->sec_vectors[ARMV7M_EXCP_MEM].pending) {
798                 val |= (1 << 13);
799             }
800             if (s->sec_vectors[ARMV7M_EXCP_SVC].pending) {
801                 val |= (1 << 15);
802             }
803             if (s->sec_vectors[ARMV7M_EXCP_MEM].enabled) {
804                 val |= (1 << 16);
805             }
806             if (s->sec_vectors[ARMV7M_EXCP_USAGE].enabled) {
807                 val |= (1 << 18);
808             }
809             if (s->sec_vectors[ARMV7M_EXCP_HARD].pending) {
810                 val |= (1 << 21);
811             }
812             /* SecureFault is not banked but is always RAZ/WI to NS */
813             if (s->vectors[ARMV7M_EXCP_SECURE].active) {
814                 val |= (1 << 4);
815             }
816             if (s->vectors[ARMV7M_EXCP_SECURE].enabled) {
817                 val |= (1 << 19);
818             }
819             if (s->vectors[ARMV7M_EXCP_SECURE].pending) {
820                 val |= (1 << 20);
821             }
822         } else {
823             if (s->vectors[ARMV7M_EXCP_MEM].active) {
824                 val |= (1 << 0);
825             }
826             if (arm_feature(&cpu->env, ARM_FEATURE_V8)) {
827                 /* HARDFAULTACT, HARDFAULTPENDED not present in v7M */
828                 if (s->vectors[ARMV7M_EXCP_HARD].active) {
829                     val |= (1 << 2);
830                 }
831                 if (s->vectors[ARMV7M_EXCP_HARD].pending) {
832                     val |= (1 << 21);
833                 }
834             }
835             if (s->vectors[ARMV7M_EXCP_USAGE].active) {
836                 val |= (1 << 3);
837             }
838             if (s->vectors[ARMV7M_EXCP_SVC].active) {
839                 val |= (1 << 7);
840             }
841             if (s->vectors[ARMV7M_EXCP_PENDSV].active) {
842                 val |= (1 << 10);
843             }
844             if (s->vectors[ARMV7M_EXCP_SYSTICK].active) {
845                 val |= (1 << 11);
846             }
847             if (s->vectors[ARMV7M_EXCP_USAGE].pending) {
848                 val |= (1 << 12);
849             }
850             if (s->vectors[ARMV7M_EXCP_MEM].pending) {
851                 val |= (1 << 13);
852             }
853             if (s->vectors[ARMV7M_EXCP_SVC].pending) {
854                 val |= (1 << 15);
855             }
856             if (s->vectors[ARMV7M_EXCP_MEM].enabled) {
857                 val |= (1 << 16);
858             }
859             if (s->vectors[ARMV7M_EXCP_USAGE].enabled) {
860                 val |= (1 << 18);
861             }
862         }
863         if (attrs.secure || (cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK)) {
864             if (s->vectors[ARMV7M_EXCP_BUS].active) {
865                 val |= (1 << 1);
866             }
867             if (s->vectors[ARMV7M_EXCP_BUS].pending) {
868                 val |= (1 << 14);
869             }
870             if (s->vectors[ARMV7M_EXCP_BUS].enabled) {
871                 val |= (1 << 17);
872             }
873             if (arm_feature(&cpu->env, ARM_FEATURE_V8) &&
874                 s->vectors[ARMV7M_EXCP_NMI].active) {
875                 /* NMIACT is not present in v7M */
876                 val |= (1 << 5);
877             }
878         }
879 
880         /* TODO: this is RAZ/WI from NS if DEMCR.SDME is set */
881         if (s->vectors[ARMV7M_EXCP_DEBUG].active) {
882             val |= (1 << 8);
883         }
884         return val;
885     case 0xd28: /* Configurable Fault Status.  */
886         /* The BFSR bits [15:8] are shared between security states
887          * and we store them in the NS copy
888          */
889         val = cpu->env.v7m.cfsr[attrs.secure];
890         val |= cpu->env.v7m.cfsr[M_REG_NS] & R_V7M_CFSR_BFSR_MASK;
891         return val;
892     case 0xd2c: /* Hard Fault Status.  */
893         return cpu->env.v7m.hfsr;
894     case 0xd30: /* Debug Fault Status.  */
895         return cpu->env.v7m.dfsr;
896     case 0xd34: /* MMFAR MemManage Fault Address */
897         return cpu->env.v7m.mmfar[attrs.secure];
898     case 0xd38: /* Bus Fault Address.  */
899         return cpu->env.v7m.bfar;
900     case 0xd3c: /* Aux Fault Status.  */
901         /* TODO: Implement fault status registers.  */
902         qemu_log_mask(LOG_UNIMP,
903                       "Aux Fault status registers unimplemented\n");
904         return 0;
905     case 0xd40: /* PFR0.  */
906         return 0x00000030;
907     case 0xd44: /* PRF1.  */
908         return 0x00000200;
909     case 0xd48: /* DFR0.  */
910         return 0x00100000;
911     case 0xd4c: /* AFR0.  */
912         return 0x00000000;
913     case 0xd50: /* MMFR0.  */
914         return 0x00000030;
915     case 0xd54: /* MMFR1.  */
916         return 0x00000000;
917     case 0xd58: /* MMFR2.  */
918         return 0x00000000;
919     case 0xd5c: /* MMFR3.  */
920         return 0x00000000;
921     case 0xd60: /* ISAR0.  */
922         return 0x01141110;
923     case 0xd64: /* ISAR1.  */
924         return 0x02111000;
925     case 0xd68: /* ISAR2.  */
926         return 0x21112231;
927     case 0xd6c: /* ISAR3.  */
928         return 0x01111110;
929     case 0xd70: /* ISAR4.  */
930         return 0x01310102;
931     /* TODO: Implement debug registers.  */
932     case 0xd90: /* MPU_TYPE */
933         /* Unified MPU; if the MPU is not present this value is zero */
934         return cpu->pmsav7_dregion << 8;
935         break;
936     case 0xd94: /* MPU_CTRL */
937         return cpu->env.v7m.mpu_ctrl[attrs.secure];
938     case 0xd98: /* MPU_RNR */
939         return cpu->env.pmsav7.rnr[attrs.secure];
940     case 0xd9c: /* MPU_RBAR */
941     case 0xda4: /* MPU_RBAR_A1 */
942     case 0xdac: /* MPU_RBAR_A2 */
943     case 0xdb4: /* MPU_RBAR_A3 */
944     {
945         int region = cpu->env.pmsav7.rnr[attrs.secure];
946 
947         if (arm_feature(&cpu->env, ARM_FEATURE_V8)) {
948             /* PMSAv8M handling of the aliases is different from v7M:
949              * aliases A1, A2, A3 override the low two bits of the region
950              * number in MPU_RNR, and there is no 'region' field in the
951              * RBAR register.
952              */
953             int aliasno = (offset - 0xd9c) / 8; /* 0..3 */
954             if (aliasno) {
955                 region = deposit32(region, 0, 2, aliasno);
956             }
957             if (region >= cpu->pmsav7_dregion) {
958                 return 0;
959             }
960             return cpu->env.pmsav8.rbar[attrs.secure][region];
961         }
962 
963         if (region >= cpu->pmsav7_dregion) {
964             return 0;
965         }
966         return (cpu->env.pmsav7.drbar[region] & 0x1f) | (region & 0xf);
967     }
968     case 0xda0: /* MPU_RASR (v7M), MPU_RLAR (v8M) */
969     case 0xda8: /* MPU_RASR_A1 (v7M), MPU_RLAR_A1 (v8M) */
970     case 0xdb0: /* MPU_RASR_A2 (v7M), MPU_RLAR_A2 (v8M) */
971     case 0xdb8: /* MPU_RASR_A3 (v7M), MPU_RLAR_A3 (v8M) */
972     {
973         int region = cpu->env.pmsav7.rnr[attrs.secure];
974 
975         if (arm_feature(&cpu->env, ARM_FEATURE_V8)) {
976             /* PMSAv8M handling of the aliases is different from v7M:
977              * aliases A1, A2, A3 override the low two bits of the region
978              * number in MPU_RNR.
979              */
980             int aliasno = (offset - 0xda0) / 8; /* 0..3 */
981             if (aliasno) {
982                 region = deposit32(region, 0, 2, aliasno);
983             }
984             if (region >= cpu->pmsav7_dregion) {
985                 return 0;
986             }
987             return cpu->env.pmsav8.rlar[attrs.secure][region];
988         }
989 
990         if (region >= cpu->pmsav7_dregion) {
991             return 0;
992         }
993         return ((cpu->env.pmsav7.dracr[region] & 0xffff) << 16) |
994             (cpu->env.pmsav7.drsr[region] & 0xffff);
995     }
996     case 0xdc0: /* MPU_MAIR0 */
997         if (!arm_feature(&cpu->env, ARM_FEATURE_V8)) {
998             goto bad_offset;
999         }
1000         return cpu->env.pmsav8.mair0[attrs.secure];
1001     case 0xdc4: /* MPU_MAIR1 */
1002         if (!arm_feature(&cpu->env, ARM_FEATURE_V8)) {
1003             goto bad_offset;
1004         }
1005         return cpu->env.pmsav8.mair1[attrs.secure];
1006     default:
1007     bad_offset:
1008         qemu_log_mask(LOG_GUEST_ERROR, "NVIC: Bad read offset 0x%x\n", offset);
1009         return 0;
1010     }
1011 }
1012 
1013 static void nvic_writel(NVICState *s, uint32_t offset, uint32_t value,
1014                         MemTxAttrs attrs)
1015 {
1016     ARMCPU *cpu = s->cpu;
1017 
1018     switch (offset) {
1019     case 0x380 ... 0x3bf: /* NVIC_ITNS<n> */
1020     {
1021         int startvec = 32 * (offset - 0x380) + NVIC_FIRST_IRQ;
1022         int i;
1023 
1024         if (!arm_feature(&cpu->env, ARM_FEATURE_V8)) {
1025             goto bad_offset;
1026         }
1027         if (!attrs.secure) {
1028             break;
1029         }
1030         for (i = 0; i < 32 && startvec + i < s->num_irq; i++) {
1031             s->itns[startvec + i] = (value >> i) & 1;
1032         }
1033         nvic_irq_update(s);
1034         break;
1035     }
1036     case 0xd04: /* Interrupt Control State (ICSR) */
1037         if (cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK) {
1038             if (value & (1 << 31)) {
1039                 armv7m_nvic_set_pending(s, ARMV7M_EXCP_NMI, false);
1040             } else if (value & (1 << 30) &&
1041                        arm_feature(&cpu->env, ARM_FEATURE_V8)) {
1042                 /* PENDNMICLR didn't exist in v7M */
1043                 armv7m_nvic_clear_pending(s, ARMV7M_EXCP_NMI, false);
1044             }
1045         }
1046         if (value & (1 << 28)) {
1047             armv7m_nvic_set_pending(s, ARMV7M_EXCP_PENDSV, attrs.secure);
1048         } else if (value & (1 << 27)) {
1049             armv7m_nvic_clear_pending(s, ARMV7M_EXCP_PENDSV, attrs.secure);
1050         }
1051         if (value & (1 << 26)) {
1052             armv7m_nvic_set_pending(s, ARMV7M_EXCP_SYSTICK, attrs.secure);
1053         } else if (value & (1 << 25)) {
1054             armv7m_nvic_clear_pending(s, ARMV7M_EXCP_SYSTICK, attrs.secure);
1055         }
1056         break;
1057     case 0xd08: /* Vector Table Offset.  */
1058         cpu->env.v7m.vecbase[attrs.secure] = value & 0xffffff80;
1059         break;
1060     case 0xd0c: /* Application Interrupt/Reset Control (AIRCR) */
1061         if ((value >> R_V7M_AIRCR_VECTKEY_SHIFT) == 0x05fa) {
1062             if (value & R_V7M_AIRCR_SYSRESETREQ_MASK) {
1063                 if (attrs.secure ||
1064                     !(cpu->env.v7m.aircr & R_V7M_AIRCR_SYSRESETREQS_MASK)) {
1065                     qemu_irq_pulse(s->sysresetreq);
1066                 }
1067             }
1068             if (value & R_V7M_AIRCR_VECTCLRACTIVE_MASK) {
1069                 qemu_log_mask(LOG_GUEST_ERROR,
1070                               "Setting VECTCLRACTIVE when not in DEBUG mode "
1071                               "is UNPREDICTABLE\n");
1072             }
1073             if (value & R_V7M_AIRCR_VECTRESET_MASK) {
1074                 /* NB: this bit is RES0 in v8M */
1075                 qemu_log_mask(LOG_GUEST_ERROR,
1076                               "Setting VECTRESET when not in DEBUG mode "
1077                               "is UNPREDICTABLE\n");
1078             }
1079             s->prigroup[attrs.secure] = extract32(value,
1080                                                   R_V7M_AIRCR_PRIGROUP_SHIFT,
1081                                                   R_V7M_AIRCR_PRIGROUP_LENGTH);
1082             if (attrs.secure) {
1083                 /* These bits are only writable by secure */
1084                 cpu->env.v7m.aircr = value &
1085                     (R_V7M_AIRCR_SYSRESETREQS_MASK |
1086                      R_V7M_AIRCR_BFHFNMINS_MASK |
1087                      R_V7M_AIRCR_PRIS_MASK);
1088                 /* BFHFNMINS changes the priority of Secure HardFault, and
1089                  * allows a pending Non-secure HardFault to preempt (which
1090                  * we implement by marking it enabled).
1091                  */
1092                 if (cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK) {
1093                     s->sec_vectors[ARMV7M_EXCP_HARD].prio = -3;
1094                     s->vectors[ARMV7M_EXCP_HARD].enabled = 1;
1095                 } else {
1096                     s->sec_vectors[ARMV7M_EXCP_HARD].prio = -1;
1097                     s->vectors[ARMV7M_EXCP_HARD].enabled = 0;
1098                 }
1099             }
1100             nvic_irq_update(s);
1101         }
1102         break;
1103     case 0xd10: /* System Control.  */
1104         /* TODO: Implement control registers.  */
1105         qemu_log_mask(LOG_UNIMP, "NVIC: SCR unimplemented\n");
1106         break;
1107     case 0xd14: /* Configuration Control.  */
1108         /* Enforce RAZ/WI on reserved and must-RAZ/WI bits */
1109         value &= (R_V7M_CCR_STKALIGN_MASK |
1110                   R_V7M_CCR_BFHFNMIGN_MASK |
1111                   R_V7M_CCR_DIV_0_TRP_MASK |
1112                   R_V7M_CCR_UNALIGN_TRP_MASK |
1113                   R_V7M_CCR_USERSETMPEND_MASK |
1114                   R_V7M_CCR_NONBASETHRDENA_MASK);
1115 
1116         if (arm_feature(&cpu->env, ARM_FEATURE_V8)) {
1117             /* v8M makes NONBASETHRDENA and STKALIGN be RES1 */
1118             value |= R_V7M_CCR_NONBASETHRDENA_MASK
1119                 | R_V7M_CCR_STKALIGN_MASK;
1120         }
1121         if (attrs.secure) {
1122             /* the BFHFNMIGN bit is not banked; keep that in the NS copy */
1123             cpu->env.v7m.ccr[M_REG_NS] =
1124                 (cpu->env.v7m.ccr[M_REG_NS] & ~R_V7M_CCR_BFHFNMIGN_MASK)
1125                 | (value & R_V7M_CCR_BFHFNMIGN_MASK);
1126             value &= ~R_V7M_CCR_BFHFNMIGN_MASK;
1127         }
1128 
1129         cpu->env.v7m.ccr[attrs.secure] = value;
1130         break;
1131     case 0xd24: /* System Handler Control and State (SHCSR) */
1132         if (attrs.secure) {
1133             s->sec_vectors[ARMV7M_EXCP_MEM].active = (value & (1 << 0)) != 0;
1134             /* Secure HardFault active bit cannot be written */
1135             s->sec_vectors[ARMV7M_EXCP_USAGE].active = (value & (1 << 3)) != 0;
1136             s->sec_vectors[ARMV7M_EXCP_SVC].active = (value & (1 << 7)) != 0;
1137             s->sec_vectors[ARMV7M_EXCP_PENDSV].active =
1138                 (value & (1 << 10)) != 0;
1139             s->sec_vectors[ARMV7M_EXCP_SYSTICK].active =
1140                 (value & (1 << 11)) != 0;
1141             s->sec_vectors[ARMV7M_EXCP_USAGE].pending =
1142                 (value & (1 << 12)) != 0;
1143             s->sec_vectors[ARMV7M_EXCP_MEM].pending = (value & (1 << 13)) != 0;
1144             s->sec_vectors[ARMV7M_EXCP_SVC].pending = (value & (1 << 15)) != 0;
1145             s->sec_vectors[ARMV7M_EXCP_MEM].enabled = (value & (1 << 16)) != 0;
1146             s->sec_vectors[ARMV7M_EXCP_BUS].enabled = (value & (1 << 17)) != 0;
1147             s->sec_vectors[ARMV7M_EXCP_USAGE].enabled =
1148                 (value & (1 << 18)) != 0;
1149             /* SecureFault not banked, but RAZ/WI to NS */
1150             s->vectors[ARMV7M_EXCP_SECURE].active = (value & (1 << 4)) != 0;
1151             s->vectors[ARMV7M_EXCP_SECURE].enabled = (value & (1 << 19)) != 0;
1152             s->vectors[ARMV7M_EXCP_SECURE].pending = (value & (1 << 20)) != 0;
1153         } else {
1154             s->vectors[ARMV7M_EXCP_MEM].active = (value & (1 << 0)) != 0;
1155             if (arm_feature(&cpu->env, ARM_FEATURE_V8)) {
1156                 /* HARDFAULTPENDED is not present in v7M */
1157                 s->vectors[ARMV7M_EXCP_HARD].pending = (value & (1 << 21)) != 0;
1158             }
1159             s->vectors[ARMV7M_EXCP_USAGE].active = (value & (1 << 3)) != 0;
1160             s->vectors[ARMV7M_EXCP_SVC].active = (value & (1 << 7)) != 0;
1161             s->vectors[ARMV7M_EXCP_PENDSV].active = (value & (1 << 10)) != 0;
1162             s->vectors[ARMV7M_EXCP_SYSTICK].active = (value & (1 << 11)) != 0;
1163             s->vectors[ARMV7M_EXCP_USAGE].pending = (value & (1 << 12)) != 0;
1164             s->vectors[ARMV7M_EXCP_MEM].pending = (value & (1 << 13)) != 0;
1165             s->vectors[ARMV7M_EXCP_SVC].pending = (value & (1 << 15)) != 0;
1166             s->vectors[ARMV7M_EXCP_MEM].enabled = (value & (1 << 16)) != 0;
1167             s->vectors[ARMV7M_EXCP_USAGE].enabled = (value & (1 << 18)) != 0;
1168         }
1169         if (attrs.secure || (cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK)) {
1170             s->vectors[ARMV7M_EXCP_BUS].active = (value & (1 << 1)) != 0;
1171             s->vectors[ARMV7M_EXCP_BUS].pending = (value & (1 << 14)) != 0;
1172             s->vectors[ARMV7M_EXCP_BUS].enabled = (value & (1 << 17)) != 0;
1173         }
1174         /* NMIACT can only be written if the write is of a zero, with
1175          * BFHFNMINS 1, and by the CPU in secure state via the NS alias.
1176          */
1177         if (!attrs.secure && cpu->env.v7m.secure &&
1178             (cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK) &&
1179             (value & (1 << 5)) == 0) {
1180             s->vectors[ARMV7M_EXCP_NMI].active = 0;
1181         }
1182         /* HARDFAULTACT can only be written if the write is of a zero
1183          * to the non-secure HardFault state by the CPU in secure state.
1184          * The only case where we can be targeting the non-secure HF state
1185          * when in secure state is if this is a write via the NS alias
1186          * and BFHFNMINS is 1.
1187          */
1188         if (!attrs.secure && cpu->env.v7m.secure &&
1189             (cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK) &&
1190             (value & (1 << 2)) == 0) {
1191             s->vectors[ARMV7M_EXCP_HARD].active = 0;
1192         }
1193 
1194         /* TODO: this is RAZ/WI from NS if DEMCR.SDME is set */
1195         s->vectors[ARMV7M_EXCP_DEBUG].active = (value & (1 << 8)) != 0;
1196         nvic_irq_update(s);
1197         break;
1198     case 0xd28: /* Configurable Fault Status.  */
1199         cpu->env.v7m.cfsr[attrs.secure] &= ~value; /* W1C */
1200         if (attrs.secure) {
1201             /* The BFSR bits [15:8] are shared between security states
1202              * and we store them in the NS copy.
1203              */
1204             cpu->env.v7m.cfsr[M_REG_NS] &= ~(value & R_V7M_CFSR_BFSR_MASK);
1205         }
1206         break;
1207     case 0xd2c: /* Hard Fault Status.  */
1208         cpu->env.v7m.hfsr &= ~value; /* W1C */
1209         break;
1210     case 0xd30: /* Debug Fault Status.  */
1211         cpu->env.v7m.dfsr &= ~value; /* W1C */
1212         break;
1213     case 0xd34: /* Mem Manage Address.  */
1214         cpu->env.v7m.mmfar[attrs.secure] = value;
1215         return;
1216     case 0xd38: /* Bus Fault Address.  */
1217         cpu->env.v7m.bfar = value;
1218         return;
1219     case 0xd3c: /* Aux Fault Status.  */
1220         qemu_log_mask(LOG_UNIMP,
1221                       "NVIC: Aux fault status registers unimplemented\n");
1222         break;
1223     case 0xd90: /* MPU_TYPE */
1224         return; /* RO */
1225     case 0xd94: /* MPU_CTRL */
1226         if ((value &
1227              (R_V7M_MPU_CTRL_HFNMIENA_MASK | R_V7M_MPU_CTRL_ENABLE_MASK))
1228             == R_V7M_MPU_CTRL_HFNMIENA_MASK) {
1229             qemu_log_mask(LOG_GUEST_ERROR, "MPU_CTRL: HFNMIENA and !ENABLE is "
1230                           "UNPREDICTABLE\n");
1231         }
1232         cpu->env.v7m.mpu_ctrl[attrs.secure]
1233             = value & (R_V7M_MPU_CTRL_ENABLE_MASK |
1234                        R_V7M_MPU_CTRL_HFNMIENA_MASK |
1235                        R_V7M_MPU_CTRL_PRIVDEFENA_MASK);
1236         tlb_flush(CPU(cpu));
1237         break;
1238     case 0xd98: /* MPU_RNR */
1239         if (value >= cpu->pmsav7_dregion) {
1240             qemu_log_mask(LOG_GUEST_ERROR, "MPU region out of range %"
1241                           PRIu32 "/%" PRIu32 "\n",
1242                           value, cpu->pmsav7_dregion);
1243         } else {
1244             cpu->env.pmsav7.rnr[attrs.secure] = value;
1245         }
1246         break;
1247     case 0xd9c: /* MPU_RBAR */
1248     case 0xda4: /* MPU_RBAR_A1 */
1249     case 0xdac: /* MPU_RBAR_A2 */
1250     case 0xdb4: /* MPU_RBAR_A3 */
1251     {
1252         int region;
1253 
1254         if (arm_feature(&cpu->env, ARM_FEATURE_V8)) {
1255             /* PMSAv8M handling of the aliases is different from v7M:
1256              * aliases A1, A2, A3 override the low two bits of the region
1257              * number in MPU_RNR, and there is no 'region' field in the
1258              * RBAR register.
1259              */
1260             int aliasno = (offset - 0xd9c) / 8; /* 0..3 */
1261 
1262             region = cpu->env.pmsav7.rnr[attrs.secure];
1263             if (aliasno) {
1264                 region = deposit32(region, 0, 2, aliasno);
1265             }
1266             if (region >= cpu->pmsav7_dregion) {
1267                 return;
1268             }
1269             cpu->env.pmsav8.rbar[attrs.secure][region] = value;
1270             tlb_flush(CPU(cpu));
1271             return;
1272         }
1273 
1274         if (value & (1 << 4)) {
1275             /* VALID bit means use the region number specified in this
1276              * value and also update MPU_RNR.REGION with that value.
1277              */
1278             region = extract32(value, 0, 4);
1279             if (region >= cpu->pmsav7_dregion) {
1280                 qemu_log_mask(LOG_GUEST_ERROR,
1281                               "MPU region out of range %u/%" PRIu32 "\n",
1282                               region, cpu->pmsav7_dregion);
1283                 return;
1284             }
1285             cpu->env.pmsav7.rnr[attrs.secure] = region;
1286         } else {
1287             region = cpu->env.pmsav7.rnr[attrs.secure];
1288         }
1289 
1290         if (region >= cpu->pmsav7_dregion) {
1291             return;
1292         }
1293 
1294         cpu->env.pmsav7.drbar[region] = value & ~0x1f;
1295         tlb_flush(CPU(cpu));
1296         break;
1297     }
1298     case 0xda0: /* MPU_RASR (v7M), MPU_RLAR (v8M) */
1299     case 0xda8: /* MPU_RASR_A1 (v7M), MPU_RLAR_A1 (v8M) */
1300     case 0xdb0: /* MPU_RASR_A2 (v7M), MPU_RLAR_A2 (v8M) */
1301     case 0xdb8: /* MPU_RASR_A3 (v7M), MPU_RLAR_A3 (v8M) */
1302     {
1303         int region = cpu->env.pmsav7.rnr[attrs.secure];
1304 
1305         if (arm_feature(&cpu->env, ARM_FEATURE_V8)) {
1306             /* PMSAv8M handling of the aliases is different from v7M:
1307              * aliases A1, A2, A3 override the low two bits of the region
1308              * number in MPU_RNR.
1309              */
1310             int aliasno = (offset - 0xd9c) / 8; /* 0..3 */
1311 
1312             region = cpu->env.pmsav7.rnr[attrs.secure];
1313             if (aliasno) {
1314                 region = deposit32(region, 0, 2, aliasno);
1315             }
1316             if (region >= cpu->pmsav7_dregion) {
1317                 return;
1318             }
1319             cpu->env.pmsav8.rlar[attrs.secure][region] = value;
1320             tlb_flush(CPU(cpu));
1321             return;
1322         }
1323 
1324         if (region >= cpu->pmsav7_dregion) {
1325             return;
1326         }
1327 
1328         cpu->env.pmsav7.drsr[region] = value & 0xff3f;
1329         cpu->env.pmsav7.dracr[region] = (value >> 16) & 0x173f;
1330         tlb_flush(CPU(cpu));
1331         break;
1332     }
1333     case 0xdc0: /* MPU_MAIR0 */
1334         if (!arm_feature(&cpu->env, ARM_FEATURE_V8)) {
1335             goto bad_offset;
1336         }
1337         if (cpu->pmsav7_dregion) {
1338             /* Register is RES0 if no MPU regions are implemented */
1339             cpu->env.pmsav8.mair0[attrs.secure] = value;
1340         }
1341         /* We don't need to do anything else because memory attributes
1342          * only affect cacheability, and we don't implement caching.
1343          */
1344         break;
1345     case 0xdc4: /* MPU_MAIR1 */
1346         if (!arm_feature(&cpu->env, ARM_FEATURE_V8)) {
1347             goto bad_offset;
1348         }
1349         if (cpu->pmsav7_dregion) {
1350             /* Register is RES0 if no MPU regions are implemented */
1351             cpu->env.pmsav8.mair1[attrs.secure] = value;
1352         }
1353         /* We don't need to do anything else because memory attributes
1354          * only affect cacheability, and we don't implement caching.
1355          */
1356         break;
1357     case 0xf00: /* Software Triggered Interrupt Register */
1358     {
1359         int excnum = (value & 0x1ff) + NVIC_FIRST_IRQ;
1360         if (excnum < s->num_irq) {
1361             armv7m_nvic_set_pending(s, excnum, false);
1362         }
1363         break;
1364     }
1365     default:
1366     bad_offset:
1367         qemu_log_mask(LOG_GUEST_ERROR,
1368                       "NVIC: Bad write offset 0x%x\n", offset);
1369     }
1370 }
1371 
1372 static bool nvic_user_access_ok(NVICState *s, hwaddr offset, MemTxAttrs attrs)
1373 {
1374     /* Return true if unprivileged access to this register is permitted. */
1375     switch (offset) {
1376     case 0xf00: /* STIR: accessible only if CCR.USERSETMPEND permits */
1377         /* For access via STIR_NS it is the NS CCR.USERSETMPEND that
1378          * controls access even though the CPU is in Secure state (I_QDKX).
1379          */
1380         return s->cpu->env.v7m.ccr[attrs.secure] & R_V7M_CCR_USERSETMPEND_MASK;
1381     default:
1382         /* All other user accesses cause a BusFault unconditionally */
1383         return false;
1384     }
1385 }
1386 
1387 static int shpr_bank(NVICState *s, int exc, MemTxAttrs attrs)
1388 {
1389     /* Behaviour for the SHPR register field for this exception:
1390      * return M_REG_NS to use the nonsecure vector (including for
1391      * non-banked exceptions), M_REG_S for the secure version of
1392      * a banked exception, and -1 if this field should RAZ/WI.
1393      */
1394     switch (exc) {
1395     case ARMV7M_EXCP_MEM:
1396     case ARMV7M_EXCP_USAGE:
1397     case ARMV7M_EXCP_SVC:
1398     case ARMV7M_EXCP_PENDSV:
1399     case ARMV7M_EXCP_SYSTICK:
1400         /* Banked exceptions */
1401         return attrs.secure;
1402     case ARMV7M_EXCP_BUS:
1403         /* Not banked, RAZ/WI from nonsecure if BFHFNMINS is zero */
1404         if (!attrs.secure &&
1405             !(s->cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK)) {
1406             return -1;
1407         }
1408         return M_REG_NS;
1409     case ARMV7M_EXCP_SECURE:
1410         /* Not banked, RAZ/WI from nonsecure */
1411         if (!attrs.secure) {
1412             return -1;
1413         }
1414         return M_REG_NS;
1415     case ARMV7M_EXCP_DEBUG:
1416         /* Not banked. TODO should RAZ/WI if DEMCR.SDME is set */
1417         return M_REG_NS;
1418     case 8 ... 10:
1419     case 13:
1420         /* RES0 */
1421         return -1;
1422     default:
1423         /* Not reachable due to decode of SHPR register addresses */
1424         g_assert_not_reached();
1425     }
1426 }
1427 
1428 static MemTxResult nvic_sysreg_read(void *opaque, hwaddr addr,
1429                                     uint64_t *data, unsigned size,
1430                                     MemTxAttrs attrs)
1431 {
1432     NVICState *s = (NVICState *)opaque;
1433     uint32_t offset = addr;
1434     unsigned i, startvec, end;
1435     uint32_t val;
1436 
1437     if (attrs.user && !nvic_user_access_ok(s, addr, attrs)) {
1438         /* Generate BusFault for unprivileged accesses */
1439         return MEMTX_ERROR;
1440     }
1441 
1442     switch (offset) {
1443     /* reads of set and clear both return the status */
1444     case 0x100 ... 0x13f: /* NVIC Set enable */
1445         offset += 0x80;
1446         /* fall through */
1447     case 0x180 ... 0x1bf: /* NVIC Clear enable */
1448         val = 0;
1449         startvec = offset - 0x180 + NVIC_FIRST_IRQ; /* vector # */
1450 
1451         for (i = 0, end = size * 8; i < end && startvec + i < s->num_irq; i++) {
1452             if (s->vectors[startvec + i].enabled &&
1453                 (attrs.secure || s->itns[startvec + i])) {
1454                 val |= (1 << i);
1455             }
1456         }
1457         break;
1458     case 0x200 ... 0x23f: /* NVIC Set pend */
1459         offset += 0x80;
1460         /* fall through */
1461     case 0x280 ... 0x2bf: /* NVIC Clear pend */
1462         val = 0;
1463         startvec = offset - 0x280 + NVIC_FIRST_IRQ; /* vector # */
1464         for (i = 0, end = size * 8; i < end && startvec + i < s->num_irq; i++) {
1465             if (s->vectors[startvec + i].pending &&
1466                 (attrs.secure || s->itns[startvec + i])) {
1467                 val |= (1 << i);
1468             }
1469         }
1470         break;
1471     case 0x300 ... 0x33f: /* NVIC Active */
1472         val = 0;
1473         startvec = offset - 0x300 + NVIC_FIRST_IRQ; /* vector # */
1474 
1475         for (i = 0, end = size * 8; i < end && startvec + i < s->num_irq; i++) {
1476             if (s->vectors[startvec + i].active &&
1477                 (attrs.secure || s->itns[startvec + i])) {
1478                 val |= (1 << i);
1479             }
1480         }
1481         break;
1482     case 0x400 ... 0x5ef: /* NVIC Priority */
1483         val = 0;
1484         startvec = offset - 0x400 + NVIC_FIRST_IRQ; /* vector # */
1485 
1486         for (i = 0; i < size && startvec + i < s->num_irq; i++) {
1487             if (attrs.secure || s->itns[startvec + i]) {
1488                 val |= s->vectors[startvec + i].prio << (8 * i);
1489             }
1490         }
1491         break;
1492     case 0xd18 ... 0xd23: /* System Handler Priority (SHPR1, SHPR2, SHPR3) */
1493         val = 0;
1494         for (i = 0; i < size; i++) {
1495             unsigned hdlidx = (offset - 0xd14) + i;
1496             int sbank = shpr_bank(s, hdlidx, attrs);
1497 
1498             if (sbank < 0) {
1499                 continue;
1500             }
1501             val = deposit32(val, i * 8, 8, get_prio(s, hdlidx, sbank));
1502         }
1503         break;
1504     case 0xfe0 ... 0xfff: /* ID.  */
1505         if (offset & 3) {
1506             val = 0;
1507         } else {
1508             val = nvic_id[(offset - 0xfe0) >> 2];
1509         }
1510         break;
1511     default:
1512         if (size == 4) {
1513             val = nvic_readl(s, offset, attrs);
1514         } else {
1515             qemu_log_mask(LOG_GUEST_ERROR,
1516                           "NVIC: Bad read of size %d at offset 0x%x\n",
1517                           size, offset);
1518             val = 0;
1519         }
1520     }
1521 
1522     trace_nvic_sysreg_read(addr, val, size);
1523     *data = val;
1524     return MEMTX_OK;
1525 }
1526 
1527 static MemTxResult nvic_sysreg_write(void *opaque, hwaddr addr,
1528                                      uint64_t value, unsigned size,
1529                                      MemTxAttrs attrs)
1530 {
1531     NVICState *s = (NVICState *)opaque;
1532     uint32_t offset = addr;
1533     unsigned i, startvec, end;
1534     unsigned setval = 0;
1535 
1536     trace_nvic_sysreg_write(addr, value, size);
1537 
1538     if (attrs.user && !nvic_user_access_ok(s, addr, attrs)) {
1539         /* Generate BusFault for unprivileged accesses */
1540         return MEMTX_ERROR;
1541     }
1542 
1543     switch (offset) {
1544     case 0x100 ... 0x13f: /* NVIC Set enable */
1545         offset += 0x80;
1546         setval = 1;
1547         /* fall through */
1548     case 0x180 ... 0x1bf: /* NVIC Clear enable */
1549         startvec = 8 * (offset - 0x180) + NVIC_FIRST_IRQ;
1550 
1551         for (i = 0, end = size * 8; i < end && startvec + i < s->num_irq; i++) {
1552             if (value & (1 << i) &&
1553                 (attrs.secure || s->itns[startvec + i])) {
1554                 s->vectors[startvec + i].enabled = setval;
1555             }
1556         }
1557         nvic_irq_update(s);
1558         return MEMTX_OK;
1559     case 0x200 ... 0x23f: /* NVIC Set pend */
1560         /* the special logic in armv7m_nvic_set_pending()
1561          * is not needed since IRQs are never escalated
1562          */
1563         offset += 0x80;
1564         setval = 1;
1565         /* fall through */
1566     case 0x280 ... 0x2bf: /* NVIC Clear pend */
1567         startvec = 8 * (offset - 0x280) + NVIC_FIRST_IRQ; /* vector # */
1568 
1569         for (i = 0, end = size * 8; i < end && startvec + i < s->num_irq; i++) {
1570             if (value & (1 << i) &&
1571                 (attrs.secure || s->itns[startvec + i])) {
1572                 s->vectors[startvec + i].pending = setval;
1573             }
1574         }
1575         nvic_irq_update(s);
1576         return MEMTX_OK;
1577     case 0x300 ... 0x33f: /* NVIC Active */
1578         return MEMTX_OK; /* R/O */
1579     case 0x400 ... 0x5ef: /* NVIC Priority */
1580         startvec = 8 * (offset - 0x400) + NVIC_FIRST_IRQ; /* vector # */
1581 
1582         for (i = 0; i < size && startvec + i < s->num_irq; i++) {
1583             if (attrs.secure || s->itns[startvec + i]) {
1584                 set_prio(s, startvec + i, false, (value >> (i * 8)) & 0xff);
1585             }
1586         }
1587         nvic_irq_update(s);
1588         return MEMTX_OK;
1589     case 0xd18 ... 0xd23: /* System Handler Priority (SHPR1, SHPR2, SHPR3) */
1590         for (i = 0; i < size; i++) {
1591             unsigned hdlidx = (offset - 0xd14) + i;
1592             int newprio = extract32(value, i * 8, 8);
1593             int sbank = shpr_bank(s, hdlidx, attrs);
1594 
1595             if (sbank < 0) {
1596                 continue;
1597             }
1598             set_prio(s, hdlidx, sbank, newprio);
1599         }
1600         nvic_irq_update(s);
1601         return MEMTX_OK;
1602     }
1603     if (size == 4) {
1604         nvic_writel(s, offset, value, attrs);
1605         return MEMTX_OK;
1606     }
1607     qemu_log_mask(LOG_GUEST_ERROR,
1608                   "NVIC: Bad write of size %d at offset 0x%x\n", size, offset);
1609     /* This is UNPREDICTABLE; treat as RAZ/WI */
1610     return MEMTX_OK;
1611 }
1612 
1613 static const MemoryRegionOps nvic_sysreg_ops = {
1614     .read_with_attrs = nvic_sysreg_read,
1615     .write_with_attrs = nvic_sysreg_write,
1616     .endianness = DEVICE_NATIVE_ENDIAN,
1617 };
1618 
1619 static MemTxResult nvic_sysreg_ns_write(void *opaque, hwaddr addr,
1620                                         uint64_t value, unsigned size,
1621                                         MemTxAttrs attrs)
1622 {
1623     if (attrs.secure) {
1624         /* S accesses to the alias act like NS accesses to the real region */
1625         attrs.secure = 0;
1626         return nvic_sysreg_write(opaque, addr, value, size, attrs);
1627     } else {
1628         /* NS attrs are RAZ/WI for privileged, and BusFault for user */
1629         if (attrs.user) {
1630             return MEMTX_ERROR;
1631         }
1632         return MEMTX_OK;
1633     }
1634 }
1635 
1636 static MemTxResult nvic_sysreg_ns_read(void *opaque, hwaddr addr,
1637                                        uint64_t *data, unsigned size,
1638                                        MemTxAttrs attrs)
1639 {
1640     if (attrs.secure) {
1641         /* S accesses to the alias act like NS accesses to the real region */
1642         attrs.secure = 0;
1643         return nvic_sysreg_read(opaque, addr, data, size, attrs);
1644     } else {
1645         /* NS attrs are RAZ/WI for privileged, and BusFault for user */
1646         if (attrs.user) {
1647             return MEMTX_ERROR;
1648         }
1649         *data = 0;
1650         return MEMTX_OK;
1651     }
1652 }
1653 
1654 static const MemoryRegionOps nvic_sysreg_ns_ops = {
1655     .read_with_attrs = nvic_sysreg_ns_read,
1656     .write_with_attrs = nvic_sysreg_ns_write,
1657     .endianness = DEVICE_NATIVE_ENDIAN,
1658 };
1659 
1660 static int nvic_post_load(void *opaque, int version_id)
1661 {
1662     NVICState *s = opaque;
1663     unsigned i;
1664     int resetprio;
1665 
1666     /* Check for out of range priority settings */
1667     resetprio = arm_feature(&s->cpu->env, ARM_FEATURE_V8) ? -4 : -3;
1668 
1669     if (s->vectors[ARMV7M_EXCP_RESET].prio != resetprio ||
1670         s->vectors[ARMV7M_EXCP_NMI].prio != -2 ||
1671         s->vectors[ARMV7M_EXCP_HARD].prio != -1) {
1672         return 1;
1673     }
1674     for (i = ARMV7M_EXCP_MEM; i < s->num_irq; i++) {
1675         if (s->vectors[i].prio & ~0xff) {
1676             return 1;
1677         }
1678     }
1679 
1680     nvic_recompute_state(s);
1681 
1682     return 0;
1683 }
1684 
1685 static const VMStateDescription vmstate_VecInfo = {
1686     .name = "armv7m_nvic_info",
1687     .version_id = 1,
1688     .minimum_version_id = 1,
1689     .fields = (VMStateField[]) {
1690         VMSTATE_INT16(prio, VecInfo),
1691         VMSTATE_UINT8(enabled, VecInfo),
1692         VMSTATE_UINT8(pending, VecInfo),
1693         VMSTATE_UINT8(active, VecInfo),
1694         VMSTATE_UINT8(level, VecInfo),
1695         VMSTATE_END_OF_LIST()
1696     }
1697 };
1698 
1699 static bool nvic_security_needed(void *opaque)
1700 {
1701     NVICState *s = opaque;
1702 
1703     return arm_feature(&s->cpu->env, ARM_FEATURE_M_SECURITY);
1704 }
1705 
1706 static int nvic_security_post_load(void *opaque, int version_id)
1707 {
1708     NVICState *s = opaque;
1709     int i;
1710 
1711     /* Check for out of range priority settings */
1712     if (s->sec_vectors[ARMV7M_EXCP_HARD].prio != -1
1713         && s->sec_vectors[ARMV7M_EXCP_HARD].prio != -3) {
1714         /* We can't cross-check against AIRCR.BFHFNMINS as we don't know
1715          * if the CPU state has been migrated yet; a mismatch won't
1716          * cause the emulation to blow up, though.
1717          */
1718         return 1;
1719     }
1720     for (i = ARMV7M_EXCP_MEM; i < ARRAY_SIZE(s->sec_vectors); i++) {
1721         if (s->sec_vectors[i].prio & ~0xff) {
1722             return 1;
1723         }
1724     }
1725     return 0;
1726 }
1727 
1728 static const VMStateDescription vmstate_nvic_security = {
1729     .name = "nvic/m-security",
1730     .version_id = 1,
1731     .minimum_version_id = 1,
1732     .needed = nvic_security_needed,
1733     .post_load = &nvic_security_post_load,
1734     .fields = (VMStateField[]) {
1735         VMSTATE_STRUCT_ARRAY(sec_vectors, NVICState, NVIC_INTERNAL_VECTORS, 1,
1736                              vmstate_VecInfo, VecInfo),
1737         VMSTATE_UINT32(prigroup[M_REG_S], NVICState),
1738         VMSTATE_BOOL_ARRAY(itns, NVICState, NVIC_MAX_VECTORS),
1739         VMSTATE_END_OF_LIST()
1740     }
1741 };
1742 
1743 static const VMStateDescription vmstate_nvic = {
1744     .name = "armv7m_nvic",
1745     .version_id = 4,
1746     .minimum_version_id = 4,
1747     .post_load = &nvic_post_load,
1748     .fields = (VMStateField[]) {
1749         VMSTATE_STRUCT_ARRAY(vectors, NVICState, NVIC_MAX_VECTORS, 1,
1750                              vmstate_VecInfo, VecInfo),
1751         VMSTATE_UINT32(prigroup[M_REG_NS], NVICState),
1752         VMSTATE_END_OF_LIST()
1753     },
1754     .subsections = (const VMStateDescription*[]) {
1755         &vmstate_nvic_security,
1756         NULL
1757     }
1758 };
1759 
1760 static Property props_nvic[] = {
1761     /* Number of external IRQ lines (so excluding the 16 internal exceptions) */
1762     DEFINE_PROP_UINT32("num-irq", NVICState, num_irq, 64),
1763     DEFINE_PROP_END_OF_LIST()
1764 };
1765 
1766 static void armv7m_nvic_reset(DeviceState *dev)
1767 {
1768     int resetprio;
1769     NVICState *s = NVIC(dev);
1770 
1771     s->vectors[ARMV7M_EXCP_NMI].enabled = 1;
1772     /* MEM, BUS, and USAGE are enabled through
1773      * the System Handler Control register
1774      */
1775     s->vectors[ARMV7M_EXCP_SVC].enabled = 1;
1776     s->vectors[ARMV7M_EXCP_DEBUG].enabled = 1;
1777     s->vectors[ARMV7M_EXCP_PENDSV].enabled = 1;
1778     s->vectors[ARMV7M_EXCP_SYSTICK].enabled = 1;
1779 
1780     resetprio = arm_feature(&s->cpu->env, ARM_FEATURE_V8) ? -4 : -3;
1781     s->vectors[ARMV7M_EXCP_RESET].prio = resetprio;
1782     s->vectors[ARMV7M_EXCP_NMI].prio = -2;
1783     s->vectors[ARMV7M_EXCP_HARD].prio = -1;
1784 
1785     if (arm_feature(&s->cpu->env, ARM_FEATURE_M_SECURITY)) {
1786         s->sec_vectors[ARMV7M_EXCP_HARD].enabled = 1;
1787         s->sec_vectors[ARMV7M_EXCP_SVC].enabled = 1;
1788         s->sec_vectors[ARMV7M_EXCP_PENDSV].enabled = 1;
1789         s->sec_vectors[ARMV7M_EXCP_SYSTICK].enabled = 1;
1790 
1791         /* AIRCR.BFHFNMINS resets to 0 so Secure HF is priority -1 (R_CMTC) */
1792         s->sec_vectors[ARMV7M_EXCP_HARD].prio = -1;
1793         /* If AIRCR.BFHFNMINS is 0 then NS HF is (effectively) disabled */
1794         s->vectors[ARMV7M_EXCP_HARD].enabled = 0;
1795     } else {
1796         s->vectors[ARMV7M_EXCP_HARD].enabled = 1;
1797     }
1798 
1799     /* Strictly speaking the reset handler should be enabled.
1800      * However, we don't simulate soft resets through the NVIC,
1801      * and the reset vector should never be pended.
1802      * So we leave it disabled to catch logic errors.
1803      */
1804 
1805     s->exception_prio = NVIC_NOEXC_PRIO;
1806     s->vectpending = 0;
1807     s->vectpending_is_s_banked = false;
1808     s->vectpending_prio = NVIC_NOEXC_PRIO;
1809 
1810     if (arm_feature(&s->cpu->env, ARM_FEATURE_M_SECURITY)) {
1811         memset(s->itns, 0, sizeof(s->itns));
1812     } else {
1813         /* This state is constant and not guest accessible in a non-security
1814          * NVIC; we set the bits to true to avoid having to do a feature
1815          * bit check in the NVIC enable/pend/etc register accessors.
1816          */
1817         int i;
1818 
1819         for (i = NVIC_FIRST_IRQ; i < ARRAY_SIZE(s->itns); i++) {
1820             s->itns[i] = true;
1821         }
1822     }
1823 }
1824 
1825 static void nvic_systick_trigger(void *opaque, int n, int level)
1826 {
1827     NVICState *s = opaque;
1828 
1829     if (level) {
1830         /* SysTick just asked us to pend its exception.
1831          * (This is different from an external interrupt line's
1832          * behaviour.)
1833          * TODO: when we implement the banked systicks we must make
1834          * this pend the correct banked exception.
1835          */
1836         armv7m_nvic_set_pending(s, ARMV7M_EXCP_SYSTICK, false);
1837     }
1838 }
1839 
1840 static void armv7m_nvic_realize(DeviceState *dev, Error **errp)
1841 {
1842     NVICState *s = NVIC(dev);
1843     SysBusDevice *systick_sbd;
1844     Error *err = NULL;
1845     int regionlen;
1846 
1847     s->cpu = ARM_CPU(qemu_get_cpu(0));
1848     assert(s->cpu);
1849 
1850     if (s->num_irq > NVIC_MAX_IRQ) {
1851         error_setg(errp, "num-irq %d exceeds NVIC maximum", s->num_irq);
1852         return;
1853     }
1854 
1855     qdev_init_gpio_in(dev, set_irq_level, s->num_irq);
1856 
1857     /* include space for internal exception vectors */
1858     s->num_irq += NVIC_FIRST_IRQ;
1859 
1860     object_property_set_bool(OBJECT(&s->systick), true, "realized", &err);
1861     if (err != NULL) {
1862         error_propagate(errp, err);
1863         return;
1864     }
1865     systick_sbd = SYS_BUS_DEVICE(&s->systick);
1866     sysbus_connect_irq(systick_sbd, 0,
1867                        qdev_get_gpio_in_named(dev, "systick-trigger", 0));
1868 
1869     /* The NVIC and System Control Space (SCS) starts at 0xe000e000
1870      * and looks like this:
1871      *  0x004 - ICTR
1872      *  0x010 - 0xff - systick
1873      *  0x100..0x7ec - NVIC
1874      *  0x7f0..0xcff - Reserved
1875      *  0xd00..0xd3c - SCS registers
1876      *  0xd40..0xeff - Reserved or Not implemented
1877      *  0xf00 - STIR
1878      *
1879      * Some registers within this space are banked between security states.
1880      * In v8M there is a second range 0xe002e000..0xe002efff which is the
1881      * NonSecure alias SCS; secure accesses to this behave like NS accesses
1882      * to the main SCS range, and non-secure accesses (including when
1883      * the security extension is not implemented) are RAZ/WI.
1884      * Note that both the main SCS range and the alias range are defined
1885      * to be exempt from memory attribution (R_BLJT) and so the memory
1886      * transaction attribute always matches the current CPU security
1887      * state (attrs.secure == env->v7m.secure). In the nvic_sysreg_ns_ops
1888      * wrappers we change attrs.secure to indicate the NS access; so
1889      * generally code determining which banked register to use should
1890      * use attrs.secure; code determining actual behaviour of the system
1891      * should use env->v7m.secure.
1892      */
1893     regionlen = arm_feature(&s->cpu->env, ARM_FEATURE_V8) ? 0x21000 : 0x1000;
1894     memory_region_init(&s->container, OBJECT(s), "nvic", regionlen);
1895     /* The system register region goes at the bottom of the priority
1896      * stack as it covers the whole page.
1897      */
1898     memory_region_init_io(&s->sysregmem, OBJECT(s), &nvic_sysreg_ops, s,
1899                           "nvic_sysregs", 0x1000);
1900     memory_region_add_subregion(&s->container, 0, &s->sysregmem);
1901     memory_region_add_subregion_overlap(&s->container, 0x10,
1902                                         sysbus_mmio_get_region(systick_sbd, 0),
1903                                         1);
1904 
1905     if (arm_feature(&s->cpu->env, ARM_FEATURE_V8)) {
1906         memory_region_init_io(&s->sysreg_ns_mem, OBJECT(s),
1907                               &nvic_sysreg_ns_ops, s,
1908                               "nvic_sysregs_ns", 0x1000);
1909         memory_region_add_subregion(&s->container, 0x20000, &s->sysreg_ns_mem);
1910     }
1911 
1912     sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->container);
1913 }
1914 
1915 static void armv7m_nvic_instance_init(Object *obj)
1916 {
1917     /* We have a different default value for the num-irq property
1918      * than our superclass. This function runs after qdev init
1919      * has set the defaults from the Property array and before
1920      * any user-specified property setting, so just modify the
1921      * value in the GICState struct.
1922      */
1923     DeviceState *dev = DEVICE(obj);
1924     NVICState *nvic = NVIC(obj);
1925     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
1926 
1927     object_initialize(&nvic->systick, sizeof(nvic->systick), TYPE_SYSTICK);
1928     qdev_set_parent_bus(DEVICE(&nvic->systick), sysbus_get_default());
1929 
1930     sysbus_init_irq(sbd, &nvic->excpout);
1931     qdev_init_gpio_out_named(dev, &nvic->sysresetreq, "SYSRESETREQ", 1);
1932     qdev_init_gpio_in_named(dev, nvic_systick_trigger, "systick-trigger", 1);
1933 }
1934 
1935 static void armv7m_nvic_class_init(ObjectClass *klass, void *data)
1936 {
1937     DeviceClass *dc = DEVICE_CLASS(klass);
1938 
1939     dc->vmsd  = &vmstate_nvic;
1940     dc->props = props_nvic;
1941     dc->reset = armv7m_nvic_reset;
1942     dc->realize = armv7m_nvic_realize;
1943 }
1944 
1945 static const TypeInfo armv7m_nvic_info = {
1946     .name          = TYPE_NVIC,
1947     .parent        = TYPE_SYS_BUS_DEVICE,
1948     .instance_init = armv7m_nvic_instance_init,
1949     .instance_size = sizeof(NVICState),
1950     .class_init    = armv7m_nvic_class_init,
1951     .class_size    = sizeof(SysBusDeviceClass),
1952 };
1953 
1954 static void armv7m_nvic_register_types(void)
1955 {
1956     type_register_static(&armv7m_nvic_info);
1957 }
1958 
1959 type_init(armv7m_nvic_register_types)
1960