xref: /openbmc/qemu/hw/intc/armv7m_nvic.c (revision 7208b426c7347982af8f5d6f2608cab6b3431ede)
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;
323 
324     if (env->v7m.faultmask[env->v7m.secure]) {
325         running = -1;
326     } else if (env->v7m.primask[env->v7m.secure]) {
327         running = 0;
328     } else if (env->v7m.basepri[env->v7m.secure] > 0) {
329         running = env->v7m.basepri[env->v7m.secure] &
330             nvic_gprio_mask(s, env->v7m.secure);
331     } else {
332         running = NVIC_NOEXC_PRIO; /* lower than any possible priority */
333     }
334     /* consider priority of active handler */
335     return MIN(running, s->exception_prio);
336 }
337 
338 bool armv7m_nvic_can_take_pending_exception(void *opaque)
339 {
340     NVICState *s = opaque;
341 
342     return nvic_exec_prio(s) > nvic_pending_prio(s);
343 }
344 
345 int armv7m_nvic_raw_execution_priority(void *opaque)
346 {
347     NVICState *s = opaque;
348 
349     return s->exception_prio;
350 }
351 
352 /* caller must call nvic_irq_update() after this.
353  * secure indicates the bank to use for banked exceptions (we assert if
354  * we are passed secure=true for a non-banked exception).
355  */
356 static void set_prio(NVICState *s, unsigned irq, bool secure, uint8_t prio)
357 {
358     assert(irq > ARMV7M_EXCP_NMI); /* only use for configurable prios */
359     assert(irq < s->num_irq);
360 
361     if (secure) {
362         assert(exc_is_banked(irq));
363         s->sec_vectors[irq].prio = prio;
364     } else {
365         s->vectors[irq].prio = prio;
366     }
367 
368     trace_nvic_set_prio(irq, secure, prio);
369 }
370 
371 /* Return the current raw priority register value.
372  * secure indicates the bank to use for banked exceptions (we assert if
373  * we are passed secure=true for a non-banked exception).
374  */
375 static int get_prio(NVICState *s, unsigned irq, bool secure)
376 {
377     assert(irq > ARMV7M_EXCP_NMI); /* only use for configurable prios */
378     assert(irq < s->num_irq);
379 
380     if (secure) {
381         assert(exc_is_banked(irq));
382         return s->sec_vectors[irq].prio;
383     } else {
384         return s->vectors[irq].prio;
385     }
386 }
387 
388 /* Recompute state and assert irq line accordingly.
389  * Must be called after changes to:
390  *  vec->active, vec->enabled, vec->pending or vec->prio for any vector
391  *  prigroup
392  */
393 static void nvic_irq_update(NVICState *s)
394 {
395     int lvl;
396     int pend_prio;
397 
398     nvic_recompute_state(s);
399     pend_prio = nvic_pending_prio(s);
400 
401     /* Raise NVIC output if this IRQ would be taken, except that we
402      * ignore the effects of the BASEPRI, FAULTMASK and PRIMASK (which
403      * will be checked for in arm_v7m_cpu_exec_interrupt()); changes
404      * to those CPU registers don't cause us to recalculate the NVIC
405      * pending info.
406      */
407     lvl = (pend_prio < s->exception_prio);
408     trace_nvic_irq_update(s->vectpending, pend_prio, s->exception_prio, lvl);
409     qemu_set_irq(s->excpout, lvl);
410 }
411 
412 /**
413  * armv7m_nvic_clear_pending: mark the specified exception as not pending
414  * @opaque: the NVIC
415  * @irq: the exception number to mark as not pending
416  * @secure: false for non-banked exceptions or for the nonsecure
417  * version of a banked exception, true for the secure version of a banked
418  * exception.
419  *
420  * Marks the specified exception as not pending. Note that we will assert()
421  * if @secure is true and @irq does not specify one of the fixed set
422  * of architecturally banked exceptions.
423  */
424 static void armv7m_nvic_clear_pending(void *opaque, int irq, bool secure)
425 {
426     NVICState *s = (NVICState *)opaque;
427     VecInfo *vec;
428 
429     assert(irq > ARMV7M_EXCP_RESET && irq < s->num_irq);
430 
431     if (secure) {
432         assert(exc_is_banked(irq));
433         vec = &s->sec_vectors[irq];
434     } else {
435         vec = &s->vectors[irq];
436     }
437     trace_nvic_clear_pending(irq, secure, vec->enabled, vec->prio);
438     if (vec->pending) {
439         vec->pending = 0;
440         nvic_irq_update(s);
441     }
442 }
443 
444 void armv7m_nvic_set_pending(void *opaque, int irq, bool secure)
445 {
446     NVICState *s = (NVICState *)opaque;
447     bool banked = exc_is_banked(irq);
448     VecInfo *vec;
449 
450     assert(irq > ARMV7M_EXCP_RESET && irq < s->num_irq);
451     assert(!secure || banked);
452 
453     vec = (banked && secure) ? &s->sec_vectors[irq] : &s->vectors[irq];
454 
455     trace_nvic_set_pending(irq, secure, vec->enabled, vec->prio);
456 
457     if (irq >= ARMV7M_EXCP_HARD && irq < ARMV7M_EXCP_PENDSV) {
458         /* If a synchronous exception is pending then it may be
459          * escalated to HardFault if:
460          *  * it is equal or lower priority to current execution
461          *  * it is disabled
462          * (ie we need to take it immediately but we can't do so).
463          * Asynchronous exceptions (and interrupts) simply remain pending.
464          *
465          * For QEMU, we don't have any imprecise (asynchronous) faults,
466          * so we can assume that PREFETCH_ABORT and DATA_ABORT are always
467          * synchronous.
468          * Debug exceptions are awkward because only Debug exceptions
469          * resulting from the BKPT instruction should be escalated,
470          * but we don't currently implement any Debug exceptions other
471          * than those that result from BKPT, so we treat all debug exceptions
472          * as needing escalation.
473          *
474          * This all means we can identify whether to escalate based only on
475          * the exception number and don't (yet) need the caller to explicitly
476          * tell us whether this exception is synchronous or not.
477          */
478         int running = nvic_exec_prio(s);
479         bool escalate = false;
480 
481         if (exc_group_prio(s, vec->prio, secure) >= running) {
482             trace_nvic_escalate_prio(irq, vec->prio, running);
483             escalate = true;
484         } else if (!vec->enabled) {
485             trace_nvic_escalate_disabled(irq);
486             escalate = true;
487         }
488 
489         if (escalate) {
490 
491             /* We need to escalate this exception to a synchronous HardFault.
492              * If BFHFNMINS is set then we escalate to the banked HF for
493              * the target security state of the original exception; otherwise
494              * we take a Secure HardFault.
495              */
496             irq = ARMV7M_EXCP_HARD;
497             if (arm_feature(&s->cpu->env, ARM_FEATURE_M_SECURITY) &&
498                 (secure ||
499                  !(s->cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK))) {
500                 vec = &s->sec_vectors[irq];
501             } else {
502                 vec = &s->vectors[irq];
503             }
504             if (running <= vec->prio) {
505                 /* We want to escalate to HardFault but we can't take the
506                  * synchronous HardFault at this point either. This is a
507                  * Lockup condition due to a guest bug. We don't model
508                  * Lockup, so report via cpu_abort() instead.
509                  */
510                 cpu_abort(&s->cpu->parent_obj,
511                           "Lockup: can't escalate %d to HardFault "
512                           "(current priority %d)\n", irq, running);
513             }
514 
515             /* HF may be banked but there is only one shared HFSR */
516             s->cpu->env.v7m.hfsr |= R_V7M_HFSR_FORCED_MASK;
517         }
518     }
519 
520     if (!vec->pending) {
521         vec->pending = 1;
522         nvic_irq_update(s);
523     }
524 }
525 
526 /* Make pending IRQ active.  */
527 void armv7m_nvic_acknowledge_irq(void *opaque)
528 {
529     NVICState *s = (NVICState *)opaque;
530     CPUARMState *env = &s->cpu->env;
531     const int pending = s->vectpending;
532     const int running = nvic_exec_prio(s);
533     VecInfo *vec;
534 
535     assert(pending > ARMV7M_EXCP_RESET && pending < s->num_irq);
536 
537     vec = &s->vectors[pending];
538 
539     assert(vec->enabled);
540     assert(vec->pending);
541 
542     assert(s->vectpending_prio < running);
543 
544     trace_nvic_acknowledge_irq(pending, s->vectpending_prio);
545 
546     vec->active = 1;
547     vec->pending = 0;
548 
549     env->v7m.exception = s->vectpending;
550 
551     nvic_irq_update(s);
552 }
553 
554 int armv7m_nvic_complete_irq(void *opaque, int irq)
555 {
556     NVICState *s = (NVICState *)opaque;
557     VecInfo *vec;
558     int ret;
559 
560     assert(irq > ARMV7M_EXCP_RESET && irq < s->num_irq);
561 
562     vec = &s->vectors[irq];
563 
564     trace_nvic_complete_irq(irq);
565 
566     if (!vec->active) {
567         /* Tell the caller this was an illegal exception return */
568         return -1;
569     }
570 
571     ret = nvic_rettobase(s);
572 
573     vec->active = 0;
574     if (vec->level) {
575         /* Re-pend the exception if it's still held high; only
576          * happens for extenal IRQs
577          */
578         assert(irq >= NVIC_FIRST_IRQ);
579         vec->pending = 1;
580     }
581 
582     nvic_irq_update(s);
583 
584     return ret;
585 }
586 
587 /* callback when external interrupt line is changed */
588 static void set_irq_level(void *opaque, int n, int level)
589 {
590     NVICState *s = opaque;
591     VecInfo *vec;
592 
593     n += NVIC_FIRST_IRQ;
594 
595     assert(n >= NVIC_FIRST_IRQ && n < s->num_irq);
596 
597     trace_nvic_set_irq_level(n, level);
598 
599     /* The pending status of an external interrupt is
600      * latched on rising edge and exception handler return.
601      *
602      * Pulsing the IRQ will always run the handler
603      * once, and the handler will re-run until the
604      * level is low when the handler completes.
605      */
606     vec = &s->vectors[n];
607     if (level != vec->level) {
608         vec->level = level;
609         if (level) {
610             armv7m_nvic_set_pending(s, n, false);
611         }
612     }
613 }
614 
615 static uint32_t nvic_readl(NVICState *s, uint32_t offset, MemTxAttrs attrs)
616 {
617     ARMCPU *cpu = s->cpu;
618     uint32_t val;
619 
620     switch (offset) {
621     case 4: /* Interrupt Control Type.  */
622         return ((s->num_irq - NVIC_FIRST_IRQ) / 32) - 1;
623     case 0x380 ... 0x3bf: /* NVIC_ITNS<n> */
624     {
625         int startvec = 32 * (offset - 0x380) + NVIC_FIRST_IRQ;
626         int i;
627 
628         if (!arm_feature(&cpu->env, ARM_FEATURE_V8)) {
629             goto bad_offset;
630         }
631         if (!attrs.secure) {
632             return 0;
633         }
634         val = 0;
635         for (i = 0; i < 32 && startvec + i < s->num_irq; i++) {
636             if (s->itns[startvec + i]) {
637                 val |= (1 << i);
638             }
639         }
640         return val;
641     }
642     case 0xd00: /* CPUID Base.  */
643         return cpu->midr;
644     case 0xd04: /* Interrupt Control State.  */
645         /* VECTACTIVE */
646         val = cpu->env.v7m.exception;
647         /* VECTPENDING */
648         val |= (s->vectpending & 0xff) << 12;
649         /* ISRPENDING - set if any external IRQ is pending */
650         if (nvic_isrpending(s)) {
651             val |= (1 << 22);
652         }
653         /* RETTOBASE - set if only one handler is active */
654         if (nvic_rettobase(s)) {
655             val |= (1 << 11);
656         }
657         /* PENDSTSET */
658         if (s->vectors[ARMV7M_EXCP_SYSTICK].pending) {
659             val |= (1 << 26);
660         }
661         /* PENDSVSET */
662         if (s->vectors[ARMV7M_EXCP_PENDSV].pending) {
663             val |= (1 << 28);
664         }
665         /* NMIPENDSET */
666         if (s->vectors[ARMV7M_EXCP_NMI].pending) {
667             val |= (1 << 31);
668         }
669         /* ISRPREEMPT not implemented */
670         return val;
671     case 0xd08: /* Vector Table Offset.  */
672         return cpu->env.v7m.vecbase[attrs.secure];
673     case 0xd0c: /* Application Interrupt/Reset Control (AIRCR) */
674         val = 0xfa050000 | (s->prigroup[attrs.secure] << 8);
675         if (attrs.secure) {
676             /* s->aircr stores PRIS, BFHFNMINS, SYSRESETREQS */
677             val |= cpu->env.v7m.aircr;
678         } else {
679             if (arm_feature(&cpu->env, ARM_FEATURE_V8)) {
680                 /* BFHFNMINS is R/O from NS; other bits are RAZ/WI. If
681                  * security isn't supported then BFHFNMINS is RAO (and
682                  * the bit in env.v7m.aircr is always set).
683                  */
684                 val |= cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK;
685             }
686         }
687         return val;
688     case 0xd10: /* System Control.  */
689         /* TODO: Implement SLEEPONEXIT.  */
690         return 0;
691     case 0xd14: /* Configuration Control.  */
692         /* The BFHFNMIGN bit is the only non-banked bit; we
693          * keep it in the non-secure copy of the register.
694          */
695         val = cpu->env.v7m.ccr[attrs.secure];
696         val |= cpu->env.v7m.ccr[M_REG_NS] & R_V7M_CCR_BFHFNMIGN_MASK;
697         return val;
698     case 0xd24: /* System Handler Status.  */
699         val = 0;
700         if (s->vectors[ARMV7M_EXCP_MEM].active) {
701             val |= (1 << 0);
702         }
703         if (s->vectors[ARMV7M_EXCP_BUS].active) {
704             val |= (1 << 1);
705         }
706         if (s->vectors[ARMV7M_EXCP_USAGE].active) {
707             val |= (1 << 3);
708         }
709         if (s->vectors[ARMV7M_EXCP_SVC].active) {
710             val |= (1 << 7);
711         }
712         if (s->vectors[ARMV7M_EXCP_DEBUG].active) {
713             val |= (1 << 8);
714         }
715         if (s->vectors[ARMV7M_EXCP_PENDSV].active) {
716             val |= (1 << 10);
717         }
718         if (s->vectors[ARMV7M_EXCP_SYSTICK].active) {
719             val |= (1 << 11);
720         }
721         if (s->vectors[ARMV7M_EXCP_USAGE].pending) {
722             val |= (1 << 12);
723         }
724         if (s->vectors[ARMV7M_EXCP_MEM].pending) {
725             val |= (1 << 13);
726         }
727         if (s->vectors[ARMV7M_EXCP_BUS].pending) {
728             val |= (1 << 14);
729         }
730         if (s->vectors[ARMV7M_EXCP_SVC].pending) {
731             val |= (1 << 15);
732         }
733         if (s->vectors[ARMV7M_EXCP_MEM].enabled) {
734             val |= (1 << 16);
735         }
736         if (s->vectors[ARMV7M_EXCP_BUS].enabled) {
737             val |= (1 << 17);
738         }
739         if (s->vectors[ARMV7M_EXCP_USAGE].enabled) {
740             val |= (1 << 18);
741         }
742         return val;
743     case 0xd28: /* Configurable Fault Status.  */
744         /* The BFSR bits [15:8] are shared between security states
745          * and we store them in the NS copy
746          */
747         val = cpu->env.v7m.cfsr[attrs.secure];
748         val |= cpu->env.v7m.cfsr[M_REG_NS] & R_V7M_CFSR_BFSR_MASK;
749         return val;
750     case 0xd2c: /* Hard Fault Status.  */
751         return cpu->env.v7m.hfsr;
752     case 0xd30: /* Debug Fault Status.  */
753         return cpu->env.v7m.dfsr;
754     case 0xd34: /* MMFAR MemManage Fault Address */
755         return cpu->env.v7m.mmfar[attrs.secure];
756     case 0xd38: /* Bus Fault Address.  */
757         return cpu->env.v7m.bfar;
758     case 0xd3c: /* Aux Fault Status.  */
759         /* TODO: Implement fault status registers.  */
760         qemu_log_mask(LOG_UNIMP,
761                       "Aux Fault status registers unimplemented\n");
762         return 0;
763     case 0xd40: /* PFR0.  */
764         return 0x00000030;
765     case 0xd44: /* PRF1.  */
766         return 0x00000200;
767     case 0xd48: /* DFR0.  */
768         return 0x00100000;
769     case 0xd4c: /* AFR0.  */
770         return 0x00000000;
771     case 0xd50: /* MMFR0.  */
772         return 0x00000030;
773     case 0xd54: /* MMFR1.  */
774         return 0x00000000;
775     case 0xd58: /* MMFR2.  */
776         return 0x00000000;
777     case 0xd5c: /* MMFR3.  */
778         return 0x00000000;
779     case 0xd60: /* ISAR0.  */
780         return 0x01141110;
781     case 0xd64: /* ISAR1.  */
782         return 0x02111000;
783     case 0xd68: /* ISAR2.  */
784         return 0x21112231;
785     case 0xd6c: /* ISAR3.  */
786         return 0x01111110;
787     case 0xd70: /* ISAR4.  */
788         return 0x01310102;
789     /* TODO: Implement debug registers.  */
790     case 0xd90: /* MPU_TYPE */
791         /* Unified MPU; if the MPU is not present this value is zero */
792         return cpu->pmsav7_dregion << 8;
793         break;
794     case 0xd94: /* MPU_CTRL */
795         return cpu->env.v7m.mpu_ctrl[attrs.secure];
796     case 0xd98: /* MPU_RNR */
797         return cpu->env.pmsav7.rnr[attrs.secure];
798     case 0xd9c: /* MPU_RBAR */
799     case 0xda4: /* MPU_RBAR_A1 */
800     case 0xdac: /* MPU_RBAR_A2 */
801     case 0xdb4: /* MPU_RBAR_A3 */
802     {
803         int region = cpu->env.pmsav7.rnr[attrs.secure];
804 
805         if (arm_feature(&cpu->env, ARM_FEATURE_V8)) {
806             /* PMSAv8M handling of the aliases is different from v7M:
807              * aliases A1, A2, A3 override the low two bits of the region
808              * number in MPU_RNR, and there is no 'region' field in the
809              * RBAR register.
810              */
811             int aliasno = (offset - 0xd9c) / 8; /* 0..3 */
812             if (aliasno) {
813                 region = deposit32(region, 0, 2, aliasno);
814             }
815             if (region >= cpu->pmsav7_dregion) {
816                 return 0;
817             }
818             return cpu->env.pmsav8.rbar[attrs.secure][region];
819         }
820 
821         if (region >= cpu->pmsav7_dregion) {
822             return 0;
823         }
824         return (cpu->env.pmsav7.drbar[region] & 0x1f) | (region & 0xf);
825     }
826     case 0xda0: /* MPU_RASR (v7M), MPU_RLAR (v8M) */
827     case 0xda8: /* MPU_RASR_A1 (v7M), MPU_RLAR_A1 (v8M) */
828     case 0xdb0: /* MPU_RASR_A2 (v7M), MPU_RLAR_A2 (v8M) */
829     case 0xdb8: /* MPU_RASR_A3 (v7M), MPU_RLAR_A3 (v8M) */
830     {
831         int region = cpu->env.pmsav7.rnr[attrs.secure];
832 
833         if (arm_feature(&cpu->env, ARM_FEATURE_V8)) {
834             /* PMSAv8M handling of the aliases is different from v7M:
835              * aliases A1, A2, A3 override the low two bits of the region
836              * number in MPU_RNR.
837              */
838             int aliasno = (offset - 0xda0) / 8; /* 0..3 */
839             if (aliasno) {
840                 region = deposit32(region, 0, 2, aliasno);
841             }
842             if (region >= cpu->pmsav7_dregion) {
843                 return 0;
844             }
845             return cpu->env.pmsav8.rlar[attrs.secure][region];
846         }
847 
848         if (region >= cpu->pmsav7_dregion) {
849             return 0;
850         }
851         return ((cpu->env.pmsav7.dracr[region] & 0xffff) << 16) |
852             (cpu->env.pmsav7.drsr[region] & 0xffff);
853     }
854     case 0xdc0: /* MPU_MAIR0 */
855         if (!arm_feature(&cpu->env, ARM_FEATURE_V8)) {
856             goto bad_offset;
857         }
858         return cpu->env.pmsav8.mair0[attrs.secure];
859     case 0xdc4: /* MPU_MAIR1 */
860         if (!arm_feature(&cpu->env, ARM_FEATURE_V8)) {
861             goto bad_offset;
862         }
863         return cpu->env.pmsav8.mair1[attrs.secure];
864     default:
865     bad_offset:
866         qemu_log_mask(LOG_GUEST_ERROR, "NVIC: Bad read offset 0x%x\n", offset);
867         return 0;
868     }
869 }
870 
871 static void nvic_writel(NVICState *s, uint32_t offset, uint32_t value,
872                         MemTxAttrs attrs)
873 {
874     ARMCPU *cpu = s->cpu;
875 
876     switch (offset) {
877     case 0x380 ... 0x3bf: /* NVIC_ITNS<n> */
878     {
879         int startvec = 32 * (offset - 0x380) + NVIC_FIRST_IRQ;
880         int i;
881 
882         if (!arm_feature(&cpu->env, ARM_FEATURE_V8)) {
883             goto bad_offset;
884         }
885         if (!attrs.secure) {
886             break;
887         }
888         for (i = 0; i < 32 && startvec + i < s->num_irq; i++) {
889             s->itns[startvec + i] = (value >> i) & 1;
890         }
891         nvic_irq_update(s);
892         break;
893     }
894     case 0xd04: /* Interrupt Control State.  */
895         if (value & (1 << 31)) {
896             armv7m_nvic_set_pending(s, ARMV7M_EXCP_NMI, false);
897         }
898         if (value & (1 << 28)) {
899             armv7m_nvic_set_pending(s, ARMV7M_EXCP_PENDSV, attrs.secure);
900         } else if (value & (1 << 27)) {
901             armv7m_nvic_clear_pending(s, ARMV7M_EXCP_PENDSV, attrs.secure);
902         }
903         if (value & (1 << 26)) {
904             armv7m_nvic_set_pending(s, ARMV7M_EXCP_SYSTICK, attrs.secure);
905         } else if (value & (1 << 25)) {
906             armv7m_nvic_clear_pending(s, ARMV7M_EXCP_SYSTICK, attrs.secure);
907         }
908         break;
909     case 0xd08: /* Vector Table Offset.  */
910         cpu->env.v7m.vecbase[attrs.secure] = value & 0xffffff80;
911         break;
912     case 0xd0c: /* Application Interrupt/Reset Control (AIRCR) */
913         if ((value >> R_V7M_AIRCR_VECTKEY_SHIFT) == 0x05fa) {
914             if (value & R_V7M_AIRCR_SYSRESETREQ_MASK) {
915                 if (attrs.secure ||
916                     !(cpu->env.v7m.aircr & R_V7M_AIRCR_SYSRESETREQS_MASK)) {
917                     qemu_irq_pulse(s->sysresetreq);
918                 }
919             }
920             if (value & R_V7M_AIRCR_VECTCLRACTIVE_MASK) {
921                 qemu_log_mask(LOG_GUEST_ERROR,
922                               "Setting VECTCLRACTIVE when not in DEBUG mode "
923                               "is UNPREDICTABLE\n");
924             }
925             if (value & R_V7M_AIRCR_VECTRESET_MASK) {
926                 /* NB: this bit is RES0 in v8M */
927                 qemu_log_mask(LOG_GUEST_ERROR,
928                               "Setting VECTRESET when not in DEBUG mode "
929                               "is UNPREDICTABLE\n");
930             }
931             s->prigroup[attrs.secure] = extract32(value,
932                                                   R_V7M_AIRCR_PRIGROUP_SHIFT,
933                                                   R_V7M_AIRCR_PRIGROUP_LENGTH);
934             if (attrs.secure) {
935                 /* These bits are only writable by secure */
936                 cpu->env.v7m.aircr = value &
937                     (R_V7M_AIRCR_SYSRESETREQS_MASK |
938                      R_V7M_AIRCR_BFHFNMINS_MASK |
939                      R_V7M_AIRCR_PRIS_MASK);
940                 /* BFHFNMINS changes the priority of Secure HardFault, and
941                  * allows a pending Non-secure HardFault to preempt (which
942                  * we implement by marking it enabled).
943                  */
944                 if (cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK) {
945                     s->sec_vectors[ARMV7M_EXCP_HARD].prio = -3;
946                     s->vectors[ARMV7M_EXCP_HARD].enabled = 1;
947                 } else {
948                     s->sec_vectors[ARMV7M_EXCP_HARD].prio = -1;
949                     s->vectors[ARMV7M_EXCP_HARD].enabled = 0;
950                 }
951             }
952             nvic_irq_update(s);
953         }
954         break;
955     case 0xd10: /* System Control.  */
956         /* TODO: Implement control registers.  */
957         qemu_log_mask(LOG_UNIMP, "NVIC: SCR unimplemented\n");
958         break;
959     case 0xd14: /* Configuration Control.  */
960         /* Enforce RAZ/WI on reserved and must-RAZ/WI bits */
961         value &= (R_V7M_CCR_STKALIGN_MASK |
962                   R_V7M_CCR_BFHFNMIGN_MASK |
963                   R_V7M_CCR_DIV_0_TRP_MASK |
964                   R_V7M_CCR_UNALIGN_TRP_MASK |
965                   R_V7M_CCR_USERSETMPEND_MASK |
966                   R_V7M_CCR_NONBASETHRDENA_MASK);
967 
968         if (arm_feature(&cpu->env, ARM_FEATURE_V8)) {
969             /* v8M makes NONBASETHRDENA and STKALIGN be RES1 */
970             value |= R_V7M_CCR_NONBASETHRDENA_MASK
971                 | R_V7M_CCR_STKALIGN_MASK;
972         }
973         if (attrs.secure) {
974             /* the BFHFNMIGN bit is not banked; keep that in the NS copy */
975             cpu->env.v7m.ccr[M_REG_NS] =
976                 (cpu->env.v7m.ccr[M_REG_NS] & ~R_V7M_CCR_BFHFNMIGN_MASK)
977                 | (value & R_V7M_CCR_BFHFNMIGN_MASK);
978             value &= ~R_V7M_CCR_BFHFNMIGN_MASK;
979         }
980 
981         cpu->env.v7m.ccr[attrs.secure] = value;
982         break;
983     case 0xd24: /* System Handler Control.  */
984         s->vectors[ARMV7M_EXCP_MEM].active = (value & (1 << 0)) != 0;
985         s->vectors[ARMV7M_EXCP_BUS].active = (value & (1 << 1)) != 0;
986         s->vectors[ARMV7M_EXCP_USAGE].active = (value & (1 << 3)) != 0;
987         s->vectors[ARMV7M_EXCP_SVC].active = (value & (1 << 7)) != 0;
988         s->vectors[ARMV7M_EXCP_DEBUG].active = (value & (1 << 8)) != 0;
989         s->vectors[ARMV7M_EXCP_PENDSV].active = (value & (1 << 10)) != 0;
990         s->vectors[ARMV7M_EXCP_SYSTICK].active = (value & (1 << 11)) != 0;
991         s->vectors[ARMV7M_EXCP_USAGE].pending = (value & (1 << 12)) != 0;
992         s->vectors[ARMV7M_EXCP_MEM].pending = (value & (1 << 13)) != 0;
993         s->vectors[ARMV7M_EXCP_BUS].pending = (value & (1 << 14)) != 0;
994         s->vectors[ARMV7M_EXCP_SVC].pending = (value & (1 << 15)) != 0;
995         s->vectors[ARMV7M_EXCP_MEM].enabled = (value & (1 << 16)) != 0;
996         s->vectors[ARMV7M_EXCP_BUS].enabled = (value & (1 << 17)) != 0;
997         s->vectors[ARMV7M_EXCP_USAGE].enabled = (value & (1 << 18)) != 0;
998         nvic_irq_update(s);
999         break;
1000     case 0xd28: /* Configurable Fault Status.  */
1001         cpu->env.v7m.cfsr[attrs.secure] &= ~value; /* W1C */
1002         if (attrs.secure) {
1003             /* The BFSR bits [15:8] are shared between security states
1004              * and we store them in the NS copy.
1005              */
1006             cpu->env.v7m.cfsr[M_REG_NS] &= ~(value & R_V7M_CFSR_BFSR_MASK);
1007         }
1008         break;
1009     case 0xd2c: /* Hard Fault Status.  */
1010         cpu->env.v7m.hfsr &= ~value; /* W1C */
1011         break;
1012     case 0xd30: /* Debug Fault Status.  */
1013         cpu->env.v7m.dfsr &= ~value; /* W1C */
1014         break;
1015     case 0xd34: /* Mem Manage Address.  */
1016         cpu->env.v7m.mmfar[attrs.secure] = value;
1017         return;
1018     case 0xd38: /* Bus Fault Address.  */
1019         cpu->env.v7m.bfar = value;
1020         return;
1021     case 0xd3c: /* Aux Fault Status.  */
1022         qemu_log_mask(LOG_UNIMP,
1023                       "NVIC: Aux fault status registers unimplemented\n");
1024         break;
1025     case 0xd90: /* MPU_TYPE */
1026         return; /* RO */
1027     case 0xd94: /* MPU_CTRL */
1028         if ((value &
1029              (R_V7M_MPU_CTRL_HFNMIENA_MASK | R_V7M_MPU_CTRL_ENABLE_MASK))
1030             == R_V7M_MPU_CTRL_HFNMIENA_MASK) {
1031             qemu_log_mask(LOG_GUEST_ERROR, "MPU_CTRL: HFNMIENA and !ENABLE is "
1032                           "UNPREDICTABLE\n");
1033         }
1034         cpu->env.v7m.mpu_ctrl[attrs.secure]
1035             = value & (R_V7M_MPU_CTRL_ENABLE_MASK |
1036                        R_V7M_MPU_CTRL_HFNMIENA_MASK |
1037                        R_V7M_MPU_CTRL_PRIVDEFENA_MASK);
1038         tlb_flush(CPU(cpu));
1039         break;
1040     case 0xd98: /* MPU_RNR */
1041         if (value >= cpu->pmsav7_dregion) {
1042             qemu_log_mask(LOG_GUEST_ERROR, "MPU region out of range %"
1043                           PRIu32 "/%" PRIu32 "\n",
1044                           value, cpu->pmsav7_dregion);
1045         } else {
1046             cpu->env.pmsav7.rnr[attrs.secure] = value;
1047         }
1048         break;
1049     case 0xd9c: /* MPU_RBAR */
1050     case 0xda4: /* MPU_RBAR_A1 */
1051     case 0xdac: /* MPU_RBAR_A2 */
1052     case 0xdb4: /* MPU_RBAR_A3 */
1053     {
1054         int region;
1055 
1056         if (arm_feature(&cpu->env, ARM_FEATURE_V8)) {
1057             /* PMSAv8M handling of the aliases is different from v7M:
1058              * aliases A1, A2, A3 override the low two bits of the region
1059              * number in MPU_RNR, and there is no 'region' field in the
1060              * RBAR register.
1061              */
1062             int aliasno = (offset - 0xd9c) / 8; /* 0..3 */
1063 
1064             region = cpu->env.pmsav7.rnr[attrs.secure];
1065             if (aliasno) {
1066                 region = deposit32(region, 0, 2, aliasno);
1067             }
1068             if (region >= cpu->pmsav7_dregion) {
1069                 return;
1070             }
1071             cpu->env.pmsav8.rbar[attrs.secure][region] = value;
1072             tlb_flush(CPU(cpu));
1073             return;
1074         }
1075 
1076         if (value & (1 << 4)) {
1077             /* VALID bit means use the region number specified in this
1078              * value and also update MPU_RNR.REGION with that value.
1079              */
1080             region = extract32(value, 0, 4);
1081             if (region >= cpu->pmsav7_dregion) {
1082                 qemu_log_mask(LOG_GUEST_ERROR,
1083                               "MPU region out of range %u/%" PRIu32 "\n",
1084                               region, cpu->pmsav7_dregion);
1085                 return;
1086             }
1087             cpu->env.pmsav7.rnr[attrs.secure] = region;
1088         } else {
1089             region = cpu->env.pmsav7.rnr[attrs.secure];
1090         }
1091 
1092         if (region >= cpu->pmsav7_dregion) {
1093             return;
1094         }
1095 
1096         cpu->env.pmsav7.drbar[region] = value & ~0x1f;
1097         tlb_flush(CPU(cpu));
1098         break;
1099     }
1100     case 0xda0: /* MPU_RASR (v7M), MPU_RLAR (v8M) */
1101     case 0xda8: /* MPU_RASR_A1 (v7M), MPU_RLAR_A1 (v8M) */
1102     case 0xdb0: /* MPU_RASR_A2 (v7M), MPU_RLAR_A2 (v8M) */
1103     case 0xdb8: /* MPU_RASR_A3 (v7M), MPU_RLAR_A3 (v8M) */
1104     {
1105         int region = cpu->env.pmsav7.rnr[attrs.secure];
1106 
1107         if (arm_feature(&cpu->env, ARM_FEATURE_V8)) {
1108             /* PMSAv8M handling of the aliases is different from v7M:
1109              * aliases A1, A2, A3 override the low two bits of the region
1110              * number in MPU_RNR.
1111              */
1112             int aliasno = (offset - 0xd9c) / 8; /* 0..3 */
1113 
1114             region = cpu->env.pmsav7.rnr[attrs.secure];
1115             if (aliasno) {
1116                 region = deposit32(region, 0, 2, aliasno);
1117             }
1118             if (region >= cpu->pmsav7_dregion) {
1119                 return;
1120             }
1121             cpu->env.pmsav8.rlar[attrs.secure][region] = value;
1122             tlb_flush(CPU(cpu));
1123             return;
1124         }
1125 
1126         if (region >= cpu->pmsav7_dregion) {
1127             return;
1128         }
1129 
1130         cpu->env.pmsav7.drsr[region] = value & 0xff3f;
1131         cpu->env.pmsav7.dracr[region] = (value >> 16) & 0x173f;
1132         tlb_flush(CPU(cpu));
1133         break;
1134     }
1135     case 0xdc0: /* MPU_MAIR0 */
1136         if (!arm_feature(&cpu->env, ARM_FEATURE_V8)) {
1137             goto bad_offset;
1138         }
1139         if (cpu->pmsav7_dregion) {
1140             /* Register is RES0 if no MPU regions are implemented */
1141             cpu->env.pmsav8.mair0[attrs.secure] = value;
1142         }
1143         /* We don't need to do anything else because memory attributes
1144          * only affect cacheability, and we don't implement caching.
1145          */
1146         break;
1147     case 0xdc4: /* MPU_MAIR1 */
1148         if (!arm_feature(&cpu->env, ARM_FEATURE_V8)) {
1149             goto bad_offset;
1150         }
1151         if (cpu->pmsav7_dregion) {
1152             /* Register is RES0 if no MPU regions are implemented */
1153             cpu->env.pmsav8.mair1[attrs.secure] = value;
1154         }
1155         /* We don't need to do anything else because memory attributes
1156          * only affect cacheability, and we don't implement caching.
1157          */
1158         break;
1159     case 0xf00: /* Software Triggered Interrupt Register */
1160     {
1161         int excnum = (value & 0x1ff) + NVIC_FIRST_IRQ;
1162         if (excnum < s->num_irq) {
1163             armv7m_nvic_set_pending(s, excnum, false);
1164         }
1165         break;
1166     }
1167     default:
1168     bad_offset:
1169         qemu_log_mask(LOG_GUEST_ERROR,
1170                       "NVIC: Bad write offset 0x%x\n", offset);
1171     }
1172 }
1173 
1174 static bool nvic_user_access_ok(NVICState *s, hwaddr offset, MemTxAttrs attrs)
1175 {
1176     /* Return true if unprivileged access to this register is permitted. */
1177     switch (offset) {
1178     case 0xf00: /* STIR: accessible only if CCR.USERSETMPEND permits */
1179         /* For access via STIR_NS it is the NS CCR.USERSETMPEND that
1180          * controls access even though the CPU is in Secure state (I_QDKX).
1181          */
1182         return s->cpu->env.v7m.ccr[attrs.secure] & R_V7M_CCR_USERSETMPEND_MASK;
1183     default:
1184         /* All other user accesses cause a BusFault unconditionally */
1185         return false;
1186     }
1187 }
1188 
1189 static int shpr_bank(NVICState *s, int exc, MemTxAttrs attrs)
1190 {
1191     /* Behaviour for the SHPR register field for this exception:
1192      * return M_REG_NS to use the nonsecure vector (including for
1193      * non-banked exceptions), M_REG_S for the secure version of
1194      * a banked exception, and -1 if this field should RAZ/WI.
1195      */
1196     switch (exc) {
1197     case ARMV7M_EXCP_MEM:
1198     case ARMV7M_EXCP_USAGE:
1199     case ARMV7M_EXCP_SVC:
1200     case ARMV7M_EXCP_PENDSV:
1201     case ARMV7M_EXCP_SYSTICK:
1202         /* Banked exceptions */
1203         return attrs.secure;
1204     case ARMV7M_EXCP_BUS:
1205         /* Not banked, RAZ/WI from nonsecure if BFHFNMINS is zero */
1206         if (!attrs.secure &&
1207             !(s->cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK)) {
1208             return -1;
1209         }
1210         return M_REG_NS;
1211     case ARMV7M_EXCP_SECURE:
1212         /* Not banked, RAZ/WI from nonsecure */
1213         if (!attrs.secure) {
1214             return -1;
1215         }
1216         return M_REG_NS;
1217     case ARMV7M_EXCP_DEBUG:
1218         /* Not banked. TODO should RAZ/WI if DEMCR.SDME is set */
1219         return M_REG_NS;
1220     case 8 ... 10:
1221     case 13:
1222         /* RES0 */
1223         return -1;
1224     default:
1225         /* Not reachable due to decode of SHPR register addresses */
1226         g_assert_not_reached();
1227     }
1228 }
1229 
1230 static MemTxResult nvic_sysreg_read(void *opaque, hwaddr addr,
1231                                     uint64_t *data, unsigned size,
1232                                     MemTxAttrs attrs)
1233 {
1234     NVICState *s = (NVICState *)opaque;
1235     uint32_t offset = addr;
1236     unsigned i, startvec, end;
1237     uint32_t val;
1238 
1239     if (attrs.user && !nvic_user_access_ok(s, addr, attrs)) {
1240         /* Generate BusFault for unprivileged accesses */
1241         return MEMTX_ERROR;
1242     }
1243 
1244     switch (offset) {
1245     /* reads of set and clear both return the status */
1246     case 0x100 ... 0x13f: /* NVIC Set enable */
1247         offset += 0x80;
1248         /* fall through */
1249     case 0x180 ... 0x1bf: /* NVIC Clear enable */
1250         val = 0;
1251         startvec = offset - 0x180 + NVIC_FIRST_IRQ; /* vector # */
1252 
1253         for (i = 0, end = size * 8; i < end && startvec + i < s->num_irq; i++) {
1254             if (s->vectors[startvec + i].enabled &&
1255                 (attrs.secure || s->itns[startvec + i])) {
1256                 val |= (1 << i);
1257             }
1258         }
1259         break;
1260     case 0x200 ... 0x23f: /* NVIC Set pend */
1261         offset += 0x80;
1262         /* fall through */
1263     case 0x280 ... 0x2bf: /* NVIC Clear pend */
1264         val = 0;
1265         startvec = offset - 0x280 + NVIC_FIRST_IRQ; /* vector # */
1266         for (i = 0, end = size * 8; i < end && startvec + i < s->num_irq; i++) {
1267             if (s->vectors[startvec + i].pending &&
1268                 (attrs.secure || s->itns[startvec + i])) {
1269                 val |= (1 << i);
1270             }
1271         }
1272         break;
1273     case 0x300 ... 0x33f: /* NVIC Active */
1274         val = 0;
1275         startvec = offset - 0x300 + NVIC_FIRST_IRQ; /* vector # */
1276 
1277         for (i = 0, end = size * 8; i < end && startvec + i < s->num_irq; i++) {
1278             if (s->vectors[startvec + i].active &&
1279                 (attrs.secure || s->itns[startvec + i])) {
1280                 val |= (1 << i);
1281             }
1282         }
1283         break;
1284     case 0x400 ... 0x5ef: /* NVIC Priority */
1285         val = 0;
1286         startvec = offset - 0x400 + NVIC_FIRST_IRQ; /* vector # */
1287 
1288         for (i = 0; i < size && startvec + i < s->num_irq; i++) {
1289             if (attrs.secure || s->itns[startvec + i]) {
1290                 val |= s->vectors[startvec + i].prio << (8 * i);
1291             }
1292         }
1293         break;
1294     case 0xd18 ... 0xd23: /* System Handler Priority (SHPR1, SHPR2, SHPR3) */
1295         val = 0;
1296         for (i = 0; i < size; i++) {
1297             unsigned hdlidx = (offset - 0xd14) + i;
1298             int sbank = shpr_bank(s, hdlidx, attrs);
1299 
1300             if (sbank < 0) {
1301                 continue;
1302             }
1303             val = deposit32(val, i * 8, 8, get_prio(s, hdlidx, sbank));
1304         }
1305         break;
1306     case 0xfe0 ... 0xfff: /* ID.  */
1307         if (offset & 3) {
1308             val = 0;
1309         } else {
1310             val = nvic_id[(offset - 0xfe0) >> 2];
1311         }
1312         break;
1313     default:
1314         if (size == 4) {
1315             val = nvic_readl(s, offset, attrs);
1316         } else {
1317             qemu_log_mask(LOG_GUEST_ERROR,
1318                           "NVIC: Bad read of size %d at offset 0x%x\n",
1319                           size, offset);
1320             val = 0;
1321         }
1322     }
1323 
1324     trace_nvic_sysreg_read(addr, val, size);
1325     *data = val;
1326     return MEMTX_OK;
1327 }
1328 
1329 static MemTxResult nvic_sysreg_write(void *opaque, hwaddr addr,
1330                                      uint64_t value, unsigned size,
1331                                      MemTxAttrs attrs)
1332 {
1333     NVICState *s = (NVICState *)opaque;
1334     uint32_t offset = addr;
1335     unsigned i, startvec, end;
1336     unsigned setval = 0;
1337 
1338     trace_nvic_sysreg_write(addr, value, size);
1339 
1340     if (attrs.user && !nvic_user_access_ok(s, addr, attrs)) {
1341         /* Generate BusFault for unprivileged accesses */
1342         return MEMTX_ERROR;
1343     }
1344 
1345     switch (offset) {
1346     case 0x100 ... 0x13f: /* NVIC Set enable */
1347         offset += 0x80;
1348         setval = 1;
1349         /* fall through */
1350     case 0x180 ... 0x1bf: /* NVIC Clear enable */
1351         startvec = 8 * (offset - 0x180) + NVIC_FIRST_IRQ;
1352 
1353         for (i = 0, end = size * 8; i < end && startvec + i < s->num_irq; i++) {
1354             if (value & (1 << i) &&
1355                 (attrs.secure || s->itns[startvec + i])) {
1356                 s->vectors[startvec + i].enabled = setval;
1357             }
1358         }
1359         nvic_irq_update(s);
1360         return MEMTX_OK;
1361     case 0x200 ... 0x23f: /* NVIC Set pend */
1362         /* the special logic in armv7m_nvic_set_pending()
1363          * is not needed since IRQs are never escalated
1364          */
1365         offset += 0x80;
1366         setval = 1;
1367         /* fall through */
1368     case 0x280 ... 0x2bf: /* NVIC Clear pend */
1369         startvec = 8 * (offset - 0x280) + NVIC_FIRST_IRQ; /* vector # */
1370 
1371         for (i = 0, end = size * 8; i < end && startvec + i < s->num_irq; i++) {
1372             if (value & (1 << i) &&
1373                 (attrs.secure || s->itns[startvec + i])) {
1374                 s->vectors[startvec + i].pending = setval;
1375             }
1376         }
1377         nvic_irq_update(s);
1378         return MEMTX_OK;
1379     case 0x300 ... 0x33f: /* NVIC Active */
1380         return MEMTX_OK; /* R/O */
1381     case 0x400 ... 0x5ef: /* NVIC Priority */
1382         startvec = 8 * (offset - 0x400) + NVIC_FIRST_IRQ; /* vector # */
1383 
1384         for (i = 0; i < size && startvec + i < s->num_irq; i++) {
1385             if (attrs.secure || s->itns[startvec + i]) {
1386                 set_prio(s, startvec + i, false, (value >> (i * 8)) & 0xff);
1387             }
1388         }
1389         nvic_irq_update(s);
1390         return MEMTX_OK;
1391     case 0xd18 ... 0xd23: /* System Handler Priority (SHPR1, SHPR2, SHPR3) */
1392         for (i = 0; i < size; i++) {
1393             unsigned hdlidx = (offset - 0xd14) + i;
1394             int newprio = extract32(value, i * 8, 8);
1395             int sbank = shpr_bank(s, hdlidx, attrs);
1396 
1397             if (sbank < 0) {
1398                 continue;
1399             }
1400             set_prio(s, hdlidx, sbank, newprio);
1401         }
1402         nvic_irq_update(s);
1403         return MEMTX_OK;
1404     }
1405     if (size == 4) {
1406         nvic_writel(s, offset, value, attrs);
1407         return MEMTX_OK;
1408     }
1409     qemu_log_mask(LOG_GUEST_ERROR,
1410                   "NVIC: Bad write of size %d at offset 0x%x\n", size, offset);
1411     /* This is UNPREDICTABLE; treat as RAZ/WI */
1412     return MEMTX_OK;
1413 }
1414 
1415 static const MemoryRegionOps nvic_sysreg_ops = {
1416     .read_with_attrs = nvic_sysreg_read,
1417     .write_with_attrs = nvic_sysreg_write,
1418     .endianness = DEVICE_NATIVE_ENDIAN,
1419 };
1420 
1421 static MemTxResult nvic_sysreg_ns_write(void *opaque, hwaddr addr,
1422                                         uint64_t value, unsigned size,
1423                                         MemTxAttrs attrs)
1424 {
1425     if (attrs.secure) {
1426         /* S accesses to the alias act like NS accesses to the real region */
1427         attrs.secure = 0;
1428         return nvic_sysreg_write(opaque, addr, value, size, attrs);
1429     } else {
1430         /* NS attrs are RAZ/WI for privileged, and BusFault for user */
1431         if (attrs.user) {
1432             return MEMTX_ERROR;
1433         }
1434         return MEMTX_OK;
1435     }
1436 }
1437 
1438 static MemTxResult nvic_sysreg_ns_read(void *opaque, hwaddr addr,
1439                                        uint64_t *data, unsigned size,
1440                                        MemTxAttrs attrs)
1441 {
1442     if (attrs.secure) {
1443         /* S accesses to the alias act like NS accesses to the real region */
1444         attrs.secure = 0;
1445         return nvic_sysreg_read(opaque, addr, data, size, attrs);
1446     } else {
1447         /* NS attrs are RAZ/WI for privileged, and BusFault for user */
1448         if (attrs.user) {
1449             return MEMTX_ERROR;
1450         }
1451         *data = 0;
1452         return MEMTX_OK;
1453     }
1454 }
1455 
1456 static const MemoryRegionOps nvic_sysreg_ns_ops = {
1457     .read_with_attrs = nvic_sysreg_ns_read,
1458     .write_with_attrs = nvic_sysreg_ns_write,
1459     .endianness = DEVICE_NATIVE_ENDIAN,
1460 };
1461 
1462 static int nvic_post_load(void *opaque, int version_id)
1463 {
1464     NVICState *s = opaque;
1465     unsigned i;
1466     int resetprio;
1467 
1468     /* Check for out of range priority settings */
1469     resetprio = arm_feature(&s->cpu->env, ARM_FEATURE_V8) ? -4 : -3;
1470 
1471     if (s->vectors[ARMV7M_EXCP_RESET].prio != resetprio ||
1472         s->vectors[ARMV7M_EXCP_NMI].prio != -2 ||
1473         s->vectors[ARMV7M_EXCP_HARD].prio != -1) {
1474         return 1;
1475     }
1476     for (i = ARMV7M_EXCP_MEM; i < s->num_irq; i++) {
1477         if (s->vectors[i].prio & ~0xff) {
1478             return 1;
1479         }
1480     }
1481 
1482     nvic_recompute_state(s);
1483 
1484     return 0;
1485 }
1486 
1487 static const VMStateDescription vmstate_VecInfo = {
1488     .name = "armv7m_nvic_info",
1489     .version_id = 1,
1490     .minimum_version_id = 1,
1491     .fields = (VMStateField[]) {
1492         VMSTATE_INT16(prio, VecInfo),
1493         VMSTATE_UINT8(enabled, VecInfo),
1494         VMSTATE_UINT8(pending, VecInfo),
1495         VMSTATE_UINT8(active, VecInfo),
1496         VMSTATE_UINT8(level, VecInfo),
1497         VMSTATE_END_OF_LIST()
1498     }
1499 };
1500 
1501 static bool nvic_security_needed(void *opaque)
1502 {
1503     NVICState *s = opaque;
1504 
1505     return arm_feature(&s->cpu->env, ARM_FEATURE_M_SECURITY);
1506 }
1507 
1508 static int nvic_security_post_load(void *opaque, int version_id)
1509 {
1510     NVICState *s = opaque;
1511     int i;
1512 
1513     /* Check for out of range priority settings */
1514     if (s->sec_vectors[ARMV7M_EXCP_HARD].prio != -1
1515         && s->sec_vectors[ARMV7M_EXCP_HARD].prio != -3) {
1516         /* We can't cross-check against AIRCR.BFHFNMINS as we don't know
1517          * if the CPU state has been migrated yet; a mismatch won't
1518          * cause the emulation to blow up, though.
1519          */
1520         return 1;
1521     }
1522     for (i = ARMV7M_EXCP_MEM; i < ARRAY_SIZE(s->sec_vectors); i++) {
1523         if (s->sec_vectors[i].prio & ~0xff) {
1524             return 1;
1525         }
1526     }
1527     return 0;
1528 }
1529 
1530 static const VMStateDescription vmstate_nvic_security = {
1531     .name = "nvic/m-security",
1532     .version_id = 1,
1533     .minimum_version_id = 1,
1534     .needed = nvic_security_needed,
1535     .post_load = &nvic_security_post_load,
1536     .fields = (VMStateField[]) {
1537         VMSTATE_STRUCT_ARRAY(sec_vectors, NVICState, NVIC_INTERNAL_VECTORS, 1,
1538                              vmstate_VecInfo, VecInfo),
1539         VMSTATE_UINT32(prigroup[M_REG_S], NVICState),
1540         VMSTATE_BOOL_ARRAY(itns, NVICState, NVIC_MAX_VECTORS),
1541         VMSTATE_END_OF_LIST()
1542     }
1543 };
1544 
1545 static const VMStateDescription vmstate_nvic = {
1546     .name = "armv7m_nvic",
1547     .version_id = 4,
1548     .minimum_version_id = 4,
1549     .post_load = &nvic_post_load,
1550     .fields = (VMStateField[]) {
1551         VMSTATE_STRUCT_ARRAY(vectors, NVICState, NVIC_MAX_VECTORS, 1,
1552                              vmstate_VecInfo, VecInfo),
1553         VMSTATE_UINT32(prigroup[M_REG_NS], NVICState),
1554         VMSTATE_END_OF_LIST()
1555     },
1556     .subsections = (const VMStateDescription*[]) {
1557         &vmstate_nvic_security,
1558         NULL
1559     }
1560 };
1561 
1562 static Property props_nvic[] = {
1563     /* Number of external IRQ lines (so excluding the 16 internal exceptions) */
1564     DEFINE_PROP_UINT32("num-irq", NVICState, num_irq, 64),
1565     DEFINE_PROP_END_OF_LIST()
1566 };
1567 
1568 static void armv7m_nvic_reset(DeviceState *dev)
1569 {
1570     int resetprio;
1571     NVICState *s = NVIC(dev);
1572 
1573     s->vectors[ARMV7M_EXCP_NMI].enabled = 1;
1574     /* MEM, BUS, and USAGE are enabled through
1575      * the System Handler Control register
1576      */
1577     s->vectors[ARMV7M_EXCP_SVC].enabled = 1;
1578     s->vectors[ARMV7M_EXCP_DEBUG].enabled = 1;
1579     s->vectors[ARMV7M_EXCP_PENDSV].enabled = 1;
1580     s->vectors[ARMV7M_EXCP_SYSTICK].enabled = 1;
1581 
1582     resetprio = arm_feature(&s->cpu->env, ARM_FEATURE_V8) ? -4 : -3;
1583     s->vectors[ARMV7M_EXCP_RESET].prio = resetprio;
1584     s->vectors[ARMV7M_EXCP_NMI].prio = -2;
1585     s->vectors[ARMV7M_EXCP_HARD].prio = -1;
1586 
1587     if (arm_feature(&s->cpu->env, ARM_FEATURE_M_SECURITY)) {
1588         s->sec_vectors[ARMV7M_EXCP_HARD].enabled = 1;
1589         s->sec_vectors[ARMV7M_EXCP_SVC].enabled = 1;
1590         s->sec_vectors[ARMV7M_EXCP_PENDSV].enabled = 1;
1591         s->sec_vectors[ARMV7M_EXCP_SYSTICK].enabled = 1;
1592 
1593         /* AIRCR.BFHFNMINS resets to 0 so Secure HF is priority -1 (R_CMTC) */
1594         s->sec_vectors[ARMV7M_EXCP_HARD].prio = -1;
1595         /* If AIRCR.BFHFNMINS is 0 then NS HF is (effectively) disabled */
1596         s->vectors[ARMV7M_EXCP_HARD].enabled = 0;
1597     } else {
1598         s->vectors[ARMV7M_EXCP_HARD].enabled = 1;
1599     }
1600 
1601     /* Strictly speaking the reset handler should be enabled.
1602      * However, we don't simulate soft resets through the NVIC,
1603      * and the reset vector should never be pended.
1604      * So we leave it disabled to catch logic errors.
1605      */
1606 
1607     s->exception_prio = NVIC_NOEXC_PRIO;
1608     s->vectpending = 0;
1609     s->vectpending_is_s_banked = false;
1610     s->vectpending_prio = NVIC_NOEXC_PRIO;
1611 
1612     if (arm_feature(&s->cpu->env, ARM_FEATURE_M_SECURITY)) {
1613         memset(s->itns, 0, sizeof(s->itns));
1614     } else {
1615         /* This state is constant and not guest accessible in a non-security
1616          * NVIC; we set the bits to true to avoid having to do a feature
1617          * bit check in the NVIC enable/pend/etc register accessors.
1618          */
1619         int i;
1620 
1621         for (i = NVIC_FIRST_IRQ; i < ARRAY_SIZE(s->itns); i++) {
1622             s->itns[i] = true;
1623         }
1624     }
1625 }
1626 
1627 static void nvic_systick_trigger(void *opaque, int n, int level)
1628 {
1629     NVICState *s = opaque;
1630 
1631     if (level) {
1632         /* SysTick just asked us to pend its exception.
1633          * (This is different from an external interrupt line's
1634          * behaviour.)
1635          * TODO: when we implement the banked systicks we must make
1636          * this pend the correct banked exception.
1637          */
1638         armv7m_nvic_set_pending(s, ARMV7M_EXCP_SYSTICK, false);
1639     }
1640 }
1641 
1642 static void armv7m_nvic_realize(DeviceState *dev, Error **errp)
1643 {
1644     NVICState *s = NVIC(dev);
1645     SysBusDevice *systick_sbd;
1646     Error *err = NULL;
1647     int regionlen;
1648 
1649     s->cpu = ARM_CPU(qemu_get_cpu(0));
1650     assert(s->cpu);
1651 
1652     if (s->num_irq > NVIC_MAX_IRQ) {
1653         error_setg(errp, "num-irq %d exceeds NVIC maximum", s->num_irq);
1654         return;
1655     }
1656 
1657     qdev_init_gpio_in(dev, set_irq_level, s->num_irq);
1658 
1659     /* include space for internal exception vectors */
1660     s->num_irq += NVIC_FIRST_IRQ;
1661 
1662     object_property_set_bool(OBJECT(&s->systick), true, "realized", &err);
1663     if (err != NULL) {
1664         error_propagate(errp, err);
1665         return;
1666     }
1667     systick_sbd = SYS_BUS_DEVICE(&s->systick);
1668     sysbus_connect_irq(systick_sbd, 0,
1669                        qdev_get_gpio_in_named(dev, "systick-trigger", 0));
1670 
1671     /* The NVIC and System Control Space (SCS) starts at 0xe000e000
1672      * and looks like this:
1673      *  0x004 - ICTR
1674      *  0x010 - 0xff - systick
1675      *  0x100..0x7ec - NVIC
1676      *  0x7f0..0xcff - Reserved
1677      *  0xd00..0xd3c - SCS registers
1678      *  0xd40..0xeff - Reserved or Not implemented
1679      *  0xf00 - STIR
1680      *
1681      * Some registers within this space are banked between security states.
1682      * In v8M there is a second range 0xe002e000..0xe002efff which is the
1683      * NonSecure alias SCS; secure accesses to this behave like NS accesses
1684      * to the main SCS range, and non-secure accesses (including when
1685      * the security extension is not implemented) are RAZ/WI.
1686      * Note that both the main SCS range and the alias range are defined
1687      * to be exempt from memory attribution (R_BLJT) and so the memory
1688      * transaction attribute always matches the current CPU security
1689      * state (attrs.secure == env->v7m.secure). In the nvic_sysreg_ns_ops
1690      * wrappers we change attrs.secure to indicate the NS access; so
1691      * generally code determining which banked register to use should
1692      * use attrs.secure; code determining actual behaviour of the system
1693      * should use env->v7m.secure.
1694      */
1695     regionlen = arm_feature(&s->cpu->env, ARM_FEATURE_V8) ? 0x21000 : 0x1000;
1696     memory_region_init(&s->container, OBJECT(s), "nvic", regionlen);
1697     /* The system register region goes at the bottom of the priority
1698      * stack as it covers the whole page.
1699      */
1700     memory_region_init_io(&s->sysregmem, OBJECT(s), &nvic_sysreg_ops, s,
1701                           "nvic_sysregs", 0x1000);
1702     memory_region_add_subregion(&s->container, 0, &s->sysregmem);
1703     memory_region_add_subregion_overlap(&s->container, 0x10,
1704                                         sysbus_mmio_get_region(systick_sbd, 0),
1705                                         1);
1706 
1707     if (arm_feature(&s->cpu->env, ARM_FEATURE_V8)) {
1708         memory_region_init_io(&s->sysreg_ns_mem, OBJECT(s),
1709                               &nvic_sysreg_ns_ops, s,
1710                               "nvic_sysregs_ns", 0x1000);
1711         memory_region_add_subregion(&s->container, 0x20000, &s->sysreg_ns_mem);
1712     }
1713 
1714     sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->container);
1715 }
1716 
1717 static void armv7m_nvic_instance_init(Object *obj)
1718 {
1719     /* We have a different default value for the num-irq property
1720      * than our superclass. This function runs after qdev init
1721      * has set the defaults from the Property array and before
1722      * any user-specified property setting, so just modify the
1723      * value in the GICState struct.
1724      */
1725     DeviceState *dev = DEVICE(obj);
1726     NVICState *nvic = NVIC(obj);
1727     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
1728 
1729     object_initialize(&nvic->systick, sizeof(nvic->systick), TYPE_SYSTICK);
1730     qdev_set_parent_bus(DEVICE(&nvic->systick), sysbus_get_default());
1731 
1732     sysbus_init_irq(sbd, &nvic->excpout);
1733     qdev_init_gpio_out_named(dev, &nvic->sysresetreq, "SYSRESETREQ", 1);
1734     qdev_init_gpio_in_named(dev, nvic_systick_trigger, "systick-trigger", 1);
1735 }
1736 
1737 static void armv7m_nvic_class_init(ObjectClass *klass, void *data)
1738 {
1739     DeviceClass *dc = DEVICE_CLASS(klass);
1740 
1741     dc->vmsd  = &vmstate_nvic;
1742     dc->props = props_nvic;
1743     dc->reset = armv7m_nvic_reset;
1744     dc->realize = armv7m_nvic_realize;
1745 }
1746 
1747 static const TypeInfo armv7m_nvic_info = {
1748     .name          = TYPE_NVIC,
1749     .parent        = TYPE_SYS_BUS_DEVICE,
1750     .instance_init = armv7m_nvic_instance_init,
1751     .instance_size = sizeof(NVICState),
1752     .class_init    = armv7m_nvic_class_init,
1753     .class_size    = sizeof(SysBusDeviceClass),
1754 };
1755 
1756 static void armv7m_nvic_register_types(void)
1757 {
1758     type_register_static(&armv7m_nvic_info);
1759 }
1760 
1761 type_init(armv7m_nvic_register_types)
1762