xref: /openbmc/qemu/target/arm/debug_helper.c (revision 8c6631e6)
1 /*
2  * ARM debug helpers.
3  *
4  * This code is licensed under the GNU GPL v2 or later.
5  *
6  * SPDX-License-Identifier: GPL-2.0-or-later
7  */
8 #include "qemu/osdep.h"
9 #include "qemu/log.h"
10 #include "cpu.h"
11 #include "internals.h"
12 #include "cpregs.h"
13 #include "exec/exec-all.h"
14 #include "exec/helper-proto.h"
15 
16 
17 /* Return the Exception Level targeted by debug exceptions. */
18 static int arm_debug_target_el(CPUARMState *env)
19 {
20     bool secure = arm_is_secure(env);
21     bool route_to_el2 = false;
22 
23     if (arm_is_el2_enabled(env)) {
24         route_to_el2 = env->cp15.hcr_el2 & HCR_TGE ||
25                        env->cp15.mdcr_el2 & MDCR_TDE;
26     }
27 
28     if (route_to_el2) {
29         return 2;
30     } else if (arm_feature(env, ARM_FEATURE_EL3) &&
31                !arm_el_is_aa64(env, 3) && secure) {
32         return 3;
33     } else {
34         return 1;
35     }
36 }
37 
38 /*
39  * Raise an exception to the debug target el.
40  * Modify syndrome to indicate when origin and target EL are the same.
41  */
42 G_NORETURN static void
43 raise_exception_debug(CPUARMState *env, uint32_t excp, uint32_t syndrome)
44 {
45     int debug_el = arm_debug_target_el(env);
46     int cur_el = arm_current_el(env);
47 
48     /*
49      * If singlestep is targeting a lower EL than the current one, then
50      * DisasContext.ss_active must be false and we can never get here.
51      * Similarly for watchpoint and breakpoint matches.
52      */
53     assert(debug_el >= cur_el);
54     syndrome |= (debug_el == cur_el) << ARM_EL_EC_SHIFT;
55     raise_exception(env, excp, syndrome, debug_el);
56 }
57 
58 /* See AArch64.GenerateDebugExceptionsFrom() in ARM ARM pseudocode */
59 static bool aa64_generate_debug_exceptions(CPUARMState *env)
60 {
61     int cur_el = arm_current_el(env);
62     int debug_el;
63 
64     if (cur_el == 3) {
65         return false;
66     }
67 
68     /* MDCR_EL3.SDD disables debug events from Secure state */
69     if (arm_is_secure_below_el3(env)
70         && extract32(env->cp15.mdcr_el3, 16, 1)) {
71         return false;
72     }
73 
74     /*
75      * Same EL to same EL debug exceptions need MDSCR_KDE enabled
76      * while not masking the (D)ebug bit in DAIF.
77      */
78     debug_el = arm_debug_target_el(env);
79 
80     if (cur_el == debug_el) {
81         return extract32(env->cp15.mdscr_el1, 13, 1)
82             && !(env->daif & PSTATE_D);
83     }
84 
85     /* Otherwise the debug target needs to be a higher EL */
86     return debug_el > cur_el;
87 }
88 
89 static bool aa32_generate_debug_exceptions(CPUARMState *env)
90 {
91     int el = arm_current_el(env);
92 
93     if (el == 0 && arm_el_is_aa64(env, 1)) {
94         return aa64_generate_debug_exceptions(env);
95     }
96 
97     if (arm_is_secure(env)) {
98         int spd;
99 
100         if (el == 0 && (env->cp15.sder & 1)) {
101             /*
102              * SDER.SUIDEN means debug exceptions from Secure EL0
103              * are always enabled. Otherwise they are controlled by
104              * SDCR.SPD like those from other Secure ELs.
105              */
106             return true;
107         }
108 
109         spd = extract32(env->cp15.mdcr_el3, 14, 2);
110         switch (spd) {
111         case 1:
112             /* SPD == 0b01 is reserved, but behaves as 0b00. */
113         case 0:
114             /*
115              * For 0b00 we return true if external secure invasive debug
116              * is enabled. On real hardware this is controlled by external
117              * signals to the core. QEMU always permits debug, and behaves
118              * as if DBGEN, SPIDEN, NIDEN and SPNIDEN are all tied high.
119              */
120             return true;
121         case 2:
122             return false;
123         case 3:
124             return true;
125         }
126     }
127 
128     return el != 2;
129 }
130 
131 /*
132  * Return true if debugging exceptions are currently enabled.
133  * This corresponds to what in ARM ARM pseudocode would be
134  *    if UsingAArch32() then
135  *        return AArch32.GenerateDebugExceptions()
136  *    else
137  *        return AArch64.GenerateDebugExceptions()
138  * We choose to push the if() down into this function for clarity,
139  * since the pseudocode has it at all callsites except for the one in
140  * CheckSoftwareStep(), where it is elided because both branches would
141  * always return the same value.
142  */
143 bool arm_generate_debug_exceptions(CPUARMState *env)
144 {
145     if ((env->cp15.oslsr_el1 & 1) || (env->cp15.osdlr_el1 & 1)) {
146         return false;
147     }
148     if (is_a64(env)) {
149         return aa64_generate_debug_exceptions(env);
150     } else {
151         return aa32_generate_debug_exceptions(env);
152     }
153 }
154 
155 /*
156  * Is single-stepping active? (Note that the "is EL_D AArch64?" check
157  * implicitly means this always returns false in pre-v8 CPUs.)
158  */
159 bool arm_singlestep_active(CPUARMState *env)
160 {
161     return extract32(env->cp15.mdscr_el1, 0, 1)
162         && arm_el_is_aa64(env, arm_debug_target_el(env))
163         && arm_generate_debug_exceptions(env);
164 }
165 
166 /* Return true if the linked breakpoint entry lbn passes its checks */
167 static bool linked_bp_matches(ARMCPU *cpu, int lbn)
168 {
169     CPUARMState *env = &cpu->env;
170     uint64_t bcr = env->cp15.dbgbcr[lbn];
171     int brps = arm_num_brps(cpu);
172     int ctx_cmps = arm_num_ctx_cmps(cpu);
173     int bt;
174     uint32_t contextidr;
175     uint64_t hcr_el2;
176 
177     /*
178      * Links to unimplemented or non-context aware breakpoints are
179      * CONSTRAINED UNPREDICTABLE: either behave as if disabled, or
180      * as if linked to an UNKNOWN context-aware breakpoint (in which
181      * case DBGWCR<n>_EL1.LBN must indicate that breakpoint).
182      * We choose the former.
183      */
184     if (lbn >= brps || lbn < (brps - ctx_cmps)) {
185         return false;
186     }
187 
188     bcr = env->cp15.dbgbcr[lbn];
189 
190     if (extract64(bcr, 0, 1) == 0) {
191         /* Linked breakpoint disabled : generate no events */
192         return false;
193     }
194 
195     bt = extract64(bcr, 20, 4);
196     hcr_el2 = arm_hcr_el2_eff(env);
197 
198     switch (bt) {
199     case 3: /* linked context ID match */
200         switch (arm_current_el(env)) {
201         default:
202             /* Context matches never fire in AArch64 EL3 */
203             return false;
204         case 2:
205             if (!(hcr_el2 & HCR_E2H)) {
206                 /* Context matches never fire in EL2 without E2H enabled. */
207                 return false;
208             }
209             contextidr = env->cp15.contextidr_el[2];
210             break;
211         case 1:
212             contextidr = env->cp15.contextidr_el[1];
213             break;
214         case 0:
215             if ((hcr_el2 & (HCR_E2H | HCR_TGE)) == (HCR_E2H | HCR_TGE)) {
216                 contextidr = env->cp15.contextidr_el[2];
217             } else {
218                 contextidr = env->cp15.contextidr_el[1];
219             }
220             break;
221         }
222         break;
223 
224     case 7:  /* linked contextidr_el1 match */
225         contextidr = env->cp15.contextidr_el[1];
226         break;
227     case 13: /* linked contextidr_el2 match */
228         contextidr = env->cp15.contextidr_el[2];
229         break;
230 
231     case 9: /* linked VMID match (reserved if no EL2) */
232     case 11: /* linked context ID and VMID match (reserved if no EL2) */
233     case 15: /* linked full context ID match */
234     default:
235         /*
236          * Links to Unlinked context breakpoints must generate no
237          * events; we choose to do the same for reserved values too.
238          */
239         return false;
240     }
241 
242     /*
243      * We match the whole register even if this is AArch32 using the
244      * short descriptor format (in which case it holds both PROCID and ASID),
245      * since we don't implement the optional v7 context ID masking.
246      */
247     return contextidr == (uint32_t)env->cp15.dbgbvr[lbn];
248 }
249 
250 static bool bp_wp_matches(ARMCPU *cpu, int n, bool is_wp)
251 {
252     CPUARMState *env = &cpu->env;
253     uint64_t cr;
254     int pac, hmc, ssc, wt, lbn;
255     /*
256      * Note that for watchpoints the check is against the CPU security
257      * state, not the S/NS attribute on the offending data access.
258      */
259     bool is_secure = arm_is_secure(env);
260     int access_el = arm_current_el(env);
261 
262     if (is_wp) {
263         CPUWatchpoint *wp = env->cpu_watchpoint[n];
264 
265         if (!wp || !(wp->flags & BP_WATCHPOINT_HIT)) {
266             return false;
267         }
268         cr = env->cp15.dbgwcr[n];
269         if (wp->hitattrs.user) {
270             /*
271              * The LDRT/STRT/LDT/STT "unprivileged access" instructions should
272              * match watchpoints as if they were accesses done at EL0, even if
273              * the CPU is at EL1 or higher.
274              */
275             access_el = 0;
276         }
277     } else {
278         uint64_t pc = is_a64(env) ? env->pc : env->regs[15];
279 
280         if (!env->cpu_breakpoint[n] || env->cpu_breakpoint[n]->pc != pc) {
281             return false;
282         }
283         cr = env->cp15.dbgbcr[n];
284     }
285     /*
286      * The WATCHPOINT_HIT flag guarantees us that the watchpoint is
287      * enabled and that the address and access type match; for breakpoints
288      * we know the address matched; check the remaining fields, including
289      * linked breakpoints. We rely on WCR and BCR having the same layout
290      * for the LBN, SSC, HMC, PAC/PMC and is-linked fields.
291      * Note that some combinations of {PAC, HMC, SSC} are reserved and
292      * must act either like some valid combination or as if the watchpoint
293      * were disabled. We choose the former, and use this together with
294      * the fact that EL3 must always be Secure and EL2 must always be
295      * Non-Secure to simplify the code slightly compared to the full
296      * table in the ARM ARM.
297      */
298     pac = FIELD_EX64(cr, DBGWCR, PAC);
299     hmc = FIELD_EX64(cr, DBGWCR, HMC);
300     ssc = FIELD_EX64(cr, DBGWCR, SSC);
301 
302     switch (ssc) {
303     case 0:
304         break;
305     case 1:
306     case 3:
307         if (is_secure) {
308             return false;
309         }
310         break;
311     case 2:
312         if (!is_secure) {
313             return false;
314         }
315         break;
316     }
317 
318     switch (access_el) {
319     case 3:
320     case 2:
321         if (!hmc) {
322             return false;
323         }
324         break;
325     case 1:
326         if (extract32(pac, 0, 1) == 0) {
327             return false;
328         }
329         break;
330     case 0:
331         if (extract32(pac, 1, 1) == 0) {
332             return false;
333         }
334         break;
335     default:
336         g_assert_not_reached();
337     }
338 
339     wt = FIELD_EX64(cr, DBGWCR, WT);
340     lbn = FIELD_EX64(cr, DBGWCR, LBN);
341 
342     if (wt && !linked_bp_matches(cpu, lbn)) {
343         return false;
344     }
345 
346     return true;
347 }
348 
349 static bool check_watchpoints(ARMCPU *cpu)
350 {
351     CPUARMState *env = &cpu->env;
352     int n;
353 
354     /*
355      * If watchpoints are disabled globally or we can't take debug
356      * exceptions here then watchpoint firings are ignored.
357      */
358     if (extract32(env->cp15.mdscr_el1, 15, 1) == 0
359         || !arm_generate_debug_exceptions(env)) {
360         return false;
361     }
362 
363     for (n = 0; n < ARRAY_SIZE(env->cpu_watchpoint); n++) {
364         if (bp_wp_matches(cpu, n, true)) {
365             return true;
366         }
367     }
368     return false;
369 }
370 
371 bool arm_debug_check_breakpoint(CPUState *cs)
372 {
373     ARMCPU *cpu = ARM_CPU(cs);
374     CPUARMState *env = &cpu->env;
375     target_ulong pc;
376     int n;
377 
378     /*
379      * If breakpoints are disabled globally or we can't take debug
380      * exceptions here then breakpoint firings are ignored.
381      */
382     if (extract32(env->cp15.mdscr_el1, 15, 1) == 0
383         || !arm_generate_debug_exceptions(env)) {
384         return false;
385     }
386 
387     /*
388      * Single-step exceptions have priority over breakpoint exceptions.
389      * If single-step state is active-pending, suppress the bp.
390      */
391     if (arm_singlestep_active(env) && !(env->pstate & PSTATE_SS)) {
392         return false;
393     }
394 
395     /*
396      * PC alignment faults have priority over breakpoint exceptions.
397      */
398     pc = is_a64(env) ? env->pc : env->regs[15];
399     if ((is_a64(env) || !env->thumb) && (pc & 3) != 0) {
400         return false;
401     }
402 
403     /*
404      * Instruction aborts have priority over breakpoint exceptions.
405      * TODO: We would need to look up the page for PC and verify that
406      * it is present and executable.
407      */
408 
409     for (n = 0; n < ARRAY_SIZE(env->cpu_breakpoint); n++) {
410         if (bp_wp_matches(cpu, n, false)) {
411             return true;
412         }
413     }
414     return false;
415 }
416 
417 bool arm_debug_check_watchpoint(CPUState *cs, CPUWatchpoint *wp)
418 {
419     /*
420      * Called by core code when a CPU watchpoint fires; need to check if this
421      * is also an architectural watchpoint match.
422      */
423     ARMCPU *cpu = ARM_CPU(cs);
424 
425     return check_watchpoints(cpu);
426 }
427 
428 /*
429  * Return the FSR value for a debug exception (watchpoint, hardware
430  * breakpoint or BKPT insn) targeting the specified exception level.
431  */
432 static uint32_t arm_debug_exception_fsr(CPUARMState *env)
433 {
434     ARMMMUFaultInfo fi = { .type = ARMFault_Debug };
435     int target_el = arm_debug_target_el(env);
436     bool using_lpae = false;
437 
438     if (target_el == 2 || arm_el_is_aa64(env, target_el)) {
439         using_lpae = true;
440     } else if (arm_feature(env, ARM_FEATURE_PMSA) &&
441                arm_feature(env, ARM_FEATURE_V8)) {
442         using_lpae = true;
443     } else {
444         if (arm_feature(env, ARM_FEATURE_LPAE) &&
445             (env->cp15.tcr_el[target_el] & TTBCR_EAE)) {
446             using_lpae = true;
447         }
448     }
449 
450     if (using_lpae) {
451         return arm_fi_to_lfsc(&fi);
452     } else {
453         return arm_fi_to_sfsc(&fi);
454     }
455 }
456 
457 void arm_debug_excp_handler(CPUState *cs)
458 {
459     /*
460      * Called by core code when a watchpoint or breakpoint fires;
461      * need to check which one and raise the appropriate exception.
462      */
463     ARMCPU *cpu = ARM_CPU(cs);
464     CPUARMState *env = &cpu->env;
465     CPUWatchpoint *wp_hit = cs->watchpoint_hit;
466 
467     if (wp_hit) {
468         if (wp_hit->flags & BP_CPU) {
469             bool wnr = (wp_hit->flags & BP_WATCHPOINT_HIT_WRITE) != 0;
470 
471             cs->watchpoint_hit = NULL;
472 
473             env->exception.fsr = arm_debug_exception_fsr(env);
474             env->exception.vaddress = wp_hit->hitaddr;
475             raise_exception_debug(env, EXCP_DATA_ABORT,
476                                   syn_watchpoint(0, 0, wnr));
477         }
478     } else {
479         uint64_t pc = is_a64(env) ? env->pc : env->regs[15];
480 
481         /*
482          * (1) GDB breakpoints should be handled first.
483          * (2) Do not raise a CPU exception if no CPU breakpoint has fired,
484          * since singlestep is also done by generating a debug internal
485          * exception.
486          */
487         if (cpu_breakpoint_test(cs, pc, BP_GDB)
488             || !cpu_breakpoint_test(cs, pc, BP_CPU)) {
489             return;
490         }
491 
492         env->exception.fsr = arm_debug_exception_fsr(env);
493         /*
494          * FAR is UNKNOWN: clear vaddress to avoid potentially exposing
495          * values to the guest that it shouldn't be able to see at its
496          * exception/security level.
497          */
498         env->exception.vaddress = 0;
499         raise_exception_debug(env, EXCP_PREFETCH_ABORT, syn_breakpoint(0));
500     }
501 }
502 
503 /*
504  * Raise an EXCP_BKPT with the specified syndrome register value,
505  * targeting the correct exception level for debug exceptions.
506  */
507 void HELPER(exception_bkpt_insn)(CPUARMState *env, uint32_t syndrome)
508 {
509     int debug_el = arm_debug_target_el(env);
510     int cur_el = arm_current_el(env);
511 
512     /* FSR will only be used if the debug target EL is AArch32. */
513     env->exception.fsr = arm_debug_exception_fsr(env);
514     /*
515      * FAR is UNKNOWN: clear vaddress to avoid potentially exposing
516      * values to the guest that it shouldn't be able to see at its
517      * exception/security level.
518      */
519     env->exception.vaddress = 0;
520     /*
521      * Other kinds of architectural debug exception are ignored if
522      * they target an exception level below the current one (in QEMU
523      * this is checked by arm_generate_debug_exceptions()). Breakpoint
524      * instructions are special because they always generate an exception
525      * to somewhere: if they can't go to the configured debug exception
526      * level they are taken to the current exception level.
527      */
528     if (debug_el < cur_el) {
529         debug_el = cur_el;
530     }
531     raise_exception(env, EXCP_BKPT, syndrome, debug_el);
532 }
533 
534 void HELPER(exception_swstep)(CPUARMState *env, uint32_t syndrome)
535 {
536     raise_exception_debug(env, EXCP_UDEF, syndrome);
537 }
538 
539 /*
540  * Check for traps to "powerdown debug" registers, which are controlled
541  * by MDCR.TDOSA
542  */
543 static CPAccessResult access_tdosa(CPUARMState *env, const ARMCPRegInfo *ri,
544                                    bool isread)
545 {
546     int el = arm_current_el(env);
547     uint64_t mdcr_el2 = arm_mdcr_el2_eff(env);
548     bool mdcr_el2_tdosa = (mdcr_el2 & MDCR_TDOSA) || (mdcr_el2 & MDCR_TDE) ||
549         (arm_hcr_el2_eff(env) & HCR_TGE);
550 
551     if (el < 2 && mdcr_el2_tdosa) {
552         return CP_ACCESS_TRAP_EL2;
553     }
554     if (el < 3 && (env->cp15.mdcr_el3 & MDCR_TDOSA)) {
555         return CP_ACCESS_TRAP_EL3;
556     }
557     return CP_ACCESS_OK;
558 }
559 
560 /*
561  * Check for traps to "debug ROM" registers, which are controlled
562  * by MDCR_EL2.TDRA for EL2 but by the more general MDCR_EL3.TDA for EL3.
563  */
564 static CPAccessResult access_tdra(CPUARMState *env, const ARMCPRegInfo *ri,
565                                   bool isread)
566 {
567     int el = arm_current_el(env);
568     uint64_t mdcr_el2 = arm_mdcr_el2_eff(env);
569     bool mdcr_el2_tdra = (mdcr_el2 & MDCR_TDRA) || (mdcr_el2 & MDCR_TDE) ||
570         (arm_hcr_el2_eff(env) & HCR_TGE);
571 
572     if (el < 2 && mdcr_el2_tdra) {
573         return CP_ACCESS_TRAP_EL2;
574     }
575     if (el < 3 && (env->cp15.mdcr_el3 & MDCR_TDA)) {
576         return CP_ACCESS_TRAP_EL3;
577     }
578     return CP_ACCESS_OK;
579 }
580 
581 /*
582  * Check for traps to general debug registers, which are controlled
583  * by MDCR_EL2.TDA for EL2 and MDCR_EL3.TDA for EL3.
584  */
585 static CPAccessResult access_tda(CPUARMState *env, const ARMCPRegInfo *ri,
586                                   bool isread)
587 {
588     int el = arm_current_el(env);
589     uint64_t mdcr_el2 = arm_mdcr_el2_eff(env);
590     bool mdcr_el2_tda = (mdcr_el2 & MDCR_TDA) || (mdcr_el2 & MDCR_TDE) ||
591         (arm_hcr_el2_eff(env) & HCR_TGE);
592 
593     if (el < 2 && mdcr_el2_tda) {
594         return CP_ACCESS_TRAP_EL2;
595     }
596     if (el < 3 && (env->cp15.mdcr_el3 & MDCR_TDA)) {
597         return CP_ACCESS_TRAP_EL3;
598     }
599     return CP_ACCESS_OK;
600 }
601 
602 /*
603  * Check for traps to Debug Comms Channel registers. If FEAT_FGT
604  * is implemented then these are controlled by MDCR_EL2.TDCC for
605  * EL2 and MDCR_EL3.TDCC for EL3. They are also controlled by
606  * the general debug access trap bits MDCR_EL2.TDA and MDCR_EL3.TDA.
607  */
608 static CPAccessResult access_tdcc(CPUARMState *env, const ARMCPRegInfo *ri,
609                                   bool isread)
610 {
611     int el = arm_current_el(env);
612     uint64_t mdcr_el2 = arm_mdcr_el2_eff(env);
613     bool mdcr_el2_tda = (mdcr_el2 & MDCR_TDA) || (mdcr_el2 & MDCR_TDE) ||
614         (arm_hcr_el2_eff(env) & HCR_TGE);
615     bool mdcr_el2_tdcc = cpu_isar_feature(aa64_fgt, env_archcpu(env)) &&
616                                           (mdcr_el2 & MDCR_TDCC);
617     bool mdcr_el3_tdcc = cpu_isar_feature(aa64_fgt, env_archcpu(env)) &&
618                                           (env->cp15.mdcr_el3 & MDCR_TDCC);
619 
620     if (el < 2 && (mdcr_el2_tda || mdcr_el2_tdcc)) {
621         return CP_ACCESS_TRAP_EL2;
622     }
623     if (el < 3 && ((env->cp15.mdcr_el3 & MDCR_TDA) || mdcr_el3_tdcc)) {
624         return CP_ACCESS_TRAP_EL3;
625     }
626     return CP_ACCESS_OK;
627 }
628 
629 static void oslar_write(CPUARMState *env, const ARMCPRegInfo *ri,
630                         uint64_t value)
631 {
632     /*
633      * Writes to OSLAR_EL1 may update the OS lock status, which can be
634      * read via a bit in OSLSR_EL1.
635      */
636     int oslock;
637 
638     if (ri->state == ARM_CP_STATE_AA32) {
639         oslock = (value == 0xC5ACCE55);
640     } else {
641         oslock = value & 1;
642     }
643 
644     env->cp15.oslsr_el1 = deposit32(env->cp15.oslsr_el1, 1, 1, oslock);
645 }
646 
647 static void osdlr_write(CPUARMState *env, const ARMCPRegInfo *ri,
648                         uint64_t value)
649 {
650     ARMCPU *cpu = env_archcpu(env);
651     /*
652      * Only defined bit is bit 0 (DLK); if Feat_DoubleLock is not
653      * implemented this is RAZ/WI.
654      */
655     if(arm_feature(env, ARM_FEATURE_AARCH64)
656        ? cpu_isar_feature(aa64_doublelock, cpu)
657        : cpu_isar_feature(aa32_doublelock, cpu)) {
658         env->cp15.osdlr_el1 = value & 1;
659     }
660 }
661 
662 static void dbgclaimset_write(CPUARMState *env, const ARMCPRegInfo *ri,
663                               uint64_t value)
664 {
665     env->cp15.dbgclaim |= (value & 0xFF);
666 }
667 
668 static uint64_t dbgclaimset_read(CPUARMState *env, const ARMCPRegInfo *ri)
669 {
670     /* CLAIM bits are RAO */
671     return 0xFF;
672 }
673 
674 static void dbgclaimclr_write(CPUARMState *env, const ARMCPRegInfo *ri,
675                               uint64_t value)
676 {
677     env->cp15.dbgclaim &= ~(value & 0xFF);
678 }
679 
680 static const ARMCPRegInfo debug_cp_reginfo[] = {
681     /*
682      * DBGDRAR, DBGDSAR: always RAZ since we don't implement memory mapped
683      * debug components. The AArch64 version of DBGDRAR is named MDRAR_EL1;
684      * unlike DBGDRAR it is never accessible from EL0.
685      * DBGDSAR is deprecated and must RAZ from v8 anyway, so it has no AArch64
686      * accessor.
687      */
688     { .name = "DBGDRAR", .cp = 14, .crn = 1, .crm = 0, .opc1 = 0, .opc2 = 0,
689       .access = PL0_R, .accessfn = access_tdra,
690       .type = ARM_CP_CONST, .resetvalue = 0 },
691     { .name = "MDRAR_EL1", .state = ARM_CP_STATE_AA64,
692       .opc0 = 2, .opc1 = 0, .crn = 1, .crm = 0, .opc2 = 0,
693       .access = PL1_R, .accessfn = access_tdra,
694       .type = ARM_CP_CONST, .resetvalue = 0 },
695     { .name = "DBGDSAR", .cp = 14, .crn = 2, .crm = 0, .opc1 = 0, .opc2 = 0,
696       .access = PL0_R, .accessfn = access_tdra,
697       .type = ARM_CP_CONST, .resetvalue = 0 },
698     /* Monitor debug system control register; the 32-bit alias is DBGDSCRext. */
699     { .name = "MDSCR_EL1", .state = ARM_CP_STATE_BOTH,
700       .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 0, .crm = 2, .opc2 = 2,
701       .access = PL1_RW, .accessfn = access_tda,
702       .fgt = FGT_MDSCR_EL1,
703       .fieldoffset = offsetof(CPUARMState, cp15.mdscr_el1),
704       .resetvalue = 0 },
705     /*
706      * MDCCSR_EL0[30:29] map to EDSCR[30:29].  Simply RAZ as the external
707      * Debug Communication Channel is not implemented.
708      */
709     { .name = "MDCCSR_EL0", .state = ARM_CP_STATE_AA64,
710       .opc0 = 2, .opc1 = 3, .crn = 0, .crm = 1, .opc2 = 0,
711       .access = PL0_R, .accessfn = access_tdcc,
712       .type = ARM_CP_CONST, .resetvalue = 0 },
713     /*
714      * OSDTRRX_EL1/OSDTRTX_EL1 are used for save and restore of DBGDTRRX_EL0.
715      * It is a component of the Debug Communications Channel, which is not implemented.
716      */
717     { .name = "OSDTRRX_EL1", .state = ARM_CP_STATE_BOTH, .cp = 14,
718       .opc0 = 2, .opc1 = 0, .crn = 0, .crm = 0, .opc2 = 2,
719       .access = PL1_RW, .accessfn = access_tdcc,
720       .type = ARM_CP_CONST, .resetvalue = 0 },
721     { .name = "OSDTRTX_EL1", .state = ARM_CP_STATE_BOTH, .cp = 14,
722       .opc0 = 2, .opc1 = 0, .crn = 0, .crm = 3, .opc2 = 2,
723       .access = PL1_RW, .accessfn = access_tdcc,
724       .type = ARM_CP_CONST, .resetvalue = 0 },
725     /*
726      * OSECCR_EL1 provides a mechanism for an operating system
727      * to access the contents of EDECCR. EDECCR is not implemented though,
728      * as is the rest of external device mechanism.
729      */
730     { .name = "OSECCR_EL1", .state = ARM_CP_STATE_BOTH, .cp = 14,
731       .opc0 = 2, .opc1 = 0, .crn = 0, .crm = 6, .opc2 = 2,
732       .access = PL1_RW, .accessfn = access_tda,
733       .fgt = FGT_OSECCR_EL1,
734       .type = ARM_CP_CONST, .resetvalue = 0 },
735     /*
736      * DBGDSCRint[15,12,5:2] map to MDSCR_EL1[15,12,5:2].  Map all bits as
737      * it is unlikely a guest will care.
738      * We don't implement the configurable EL0 access.
739      */
740     { .name = "DBGDSCRint", .state = ARM_CP_STATE_AA32,
741       .cp = 14, .opc1 = 0, .crn = 0, .crm = 1, .opc2 = 0,
742       .type = ARM_CP_ALIAS,
743       .access = PL1_R, .accessfn = access_tda,
744       .fieldoffset = offsetof(CPUARMState, cp15.mdscr_el1), },
745     { .name = "OSLAR_EL1", .state = ARM_CP_STATE_BOTH,
746       .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 1, .crm = 0, .opc2 = 4,
747       .access = PL1_W, .type = ARM_CP_NO_RAW,
748       .accessfn = access_tdosa,
749       .fgt = FGT_OSLAR_EL1,
750       .writefn = oslar_write },
751     { .name = "OSLSR_EL1", .state = ARM_CP_STATE_BOTH,
752       .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 1, .crm = 1, .opc2 = 4,
753       .access = PL1_R, .resetvalue = 10,
754       .accessfn = access_tdosa,
755       .fgt = FGT_OSLSR_EL1,
756       .fieldoffset = offsetof(CPUARMState, cp15.oslsr_el1) },
757     /* Dummy OSDLR_EL1: 32-bit Linux will read this */
758     { .name = "OSDLR_EL1", .state = ARM_CP_STATE_BOTH,
759       .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 1, .crm = 3, .opc2 = 4,
760       .access = PL1_RW, .accessfn = access_tdosa,
761       .fgt = FGT_OSDLR_EL1,
762       .writefn = osdlr_write,
763       .fieldoffset = offsetof(CPUARMState, cp15.osdlr_el1) },
764     /*
765      * Dummy DBGVCR: Linux wants to clear this on startup, but we don't
766      * implement vector catch debug events yet.
767      */
768     { .name = "DBGVCR",
769       .cp = 14, .opc1 = 0, .crn = 0, .crm = 7, .opc2 = 0,
770       .access = PL1_RW, .accessfn = access_tda,
771       .type = ARM_CP_NOP },
772     /*
773      * Dummy DBGVCR32_EL2 (which is only for a 64-bit hypervisor
774      * to save and restore a 32-bit guest's DBGVCR)
775      */
776     { .name = "DBGVCR32_EL2", .state = ARM_CP_STATE_AA64,
777       .opc0 = 2, .opc1 = 4, .crn = 0, .crm = 7, .opc2 = 0,
778       .access = PL2_RW, .accessfn = access_tda,
779       .type = ARM_CP_NOP | ARM_CP_EL3_NO_EL2_KEEP },
780     /*
781      * Dummy MDCCINT_EL1, since we don't implement the Debug Communications
782      * Channel but Linux may try to access this register. The 32-bit
783      * alias is DBGDCCINT.
784      */
785     { .name = "MDCCINT_EL1", .state = ARM_CP_STATE_BOTH,
786       .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 0, .crm = 2, .opc2 = 0,
787       .access = PL1_RW, .accessfn = access_tdcc,
788       .type = ARM_CP_NOP },
789     /*
790      * Dummy DBGCLAIM registers.
791      * "The architecture does not define any functionality for the CLAIM tag bits.",
792      * so we only keep the raw bits
793      */
794     { .name = "DBGCLAIMSET_EL1", .state = ARM_CP_STATE_BOTH,
795       .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 7, .crm = 8, .opc2 = 6,
796       .type = ARM_CP_ALIAS,
797       .access = PL1_RW, .accessfn = access_tda,
798       .fgt = FGT_DBGCLAIM,
799       .writefn = dbgclaimset_write, .readfn = dbgclaimset_read },
800     { .name = "DBGCLAIMCLR_EL1", .state = ARM_CP_STATE_BOTH,
801       .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 7, .crm = 9, .opc2 = 6,
802       .access = PL1_RW, .accessfn = access_tda,
803       .fgt = FGT_DBGCLAIM,
804       .writefn = dbgclaimclr_write, .raw_writefn = raw_write,
805       .fieldoffset = offsetof(CPUARMState, cp15.dbgclaim) },
806 };
807 
808 static const ARMCPRegInfo debug_lpae_cp_reginfo[] = {
809     /* 64 bit access versions of the (dummy) debug registers */
810     { .name = "DBGDRAR", .cp = 14, .crm = 1, .opc1 = 0,
811       .access = PL0_R, .type = ARM_CP_CONST | ARM_CP_64BIT, .resetvalue = 0 },
812     { .name = "DBGDSAR", .cp = 14, .crm = 2, .opc1 = 0,
813       .access = PL0_R, .type = ARM_CP_CONST | ARM_CP_64BIT, .resetvalue = 0 },
814 };
815 
816 void hw_watchpoint_update(ARMCPU *cpu, int n)
817 {
818     CPUARMState *env = &cpu->env;
819     vaddr len = 0;
820     vaddr wvr = env->cp15.dbgwvr[n];
821     uint64_t wcr = env->cp15.dbgwcr[n];
822     int mask;
823     int flags = BP_CPU | BP_STOP_BEFORE_ACCESS;
824 
825     if (env->cpu_watchpoint[n]) {
826         cpu_watchpoint_remove_by_ref(CPU(cpu), env->cpu_watchpoint[n]);
827         env->cpu_watchpoint[n] = NULL;
828     }
829 
830     if (!FIELD_EX64(wcr, DBGWCR, E)) {
831         /* E bit clear : watchpoint disabled */
832         return;
833     }
834 
835     switch (FIELD_EX64(wcr, DBGWCR, LSC)) {
836     case 0:
837         /* LSC 00 is reserved and must behave as if the wp is disabled */
838         return;
839     case 1:
840         flags |= BP_MEM_READ;
841         break;
842     case 2:
843         flags |= BP_MEM_WRITE;
844         break;
845     case 3:
846         flags |= BP_MEM_ACCESS;
847         break;
848     }
849 
850     /*
851      * Attempts to use both MASK and BAS fields simultaneously are
852      * CONSTRAINED UNPREDICTABLE; we opt to ignore BAS in this case,
853      * thus generating a watchpoint for every byte in the masked region.
854      */
855     mask = FIELD_EX64(wcr, DBGWCR, MASK);
856     if (mask == 1 || mask == 2) {
857         /*
858          * Reserved values of MASK; we must act as if the mask value was
859          * some non-reserved value, or as if the watchpoint were disabled.
860          * We choose the latter.
861          */
862         return;
863     } else if (mask) {
864         /* Watchpoint covers an aligned area up to 2GB in size */
865         len = 1ULL << mask;
866         /*
867          * If masked bits in WVR are not zero it's CONSTRAINED UNPREDICTABLE
868          * whether the watchpoint fires when the unmasked bits match; we opt
869          * to generate the exceptions.
870          */
871         wvr &= ~(len - 1);
872     } else {
873         /* Watchpoint covers bytes defined by the byte address select bits */
874         int bas = FIELD_EX64(wcr, DBGWCR, BAS);
875         int basstart;
876 
877         if (extract64(wvr, 2, 1)) {
878             /*
879              * Deprecated case of an only 4-aligned address. BAS[7:4] are
880              * ignored, and BAS[3:0] define which bytes to watch.
881              */
882             bas &= 0xf;
883         }
884 
885         if (bas == 0) {
886             /* This must act as if the watchpoint is disabled */
887             return;
888         }
889 
890         /*
891          * The BAS bits are supposed to be programmed to indicate a contiguous
892          * range of bytes. Otherwise it is CONSTRAINED UNPREDICTABLE whether
893          * we fire for each byte in the word/doubleword addressed by the WVR.
894          * We choose to ignore any non-zero bits after the first range of 1s.
895          */
896         basstart = ctz32(bas);
897         len = cto32(bas >> basstart);
898         wvr += basstart;
899     }
900 
901     cpu_watchpoint_insert(CPU(cpu), wvr, len, flags,
902                           &env->cpu_watchpoint[n]);
903 }
904 
905 void hw_watchpoint_update_all(ARMCPU *cpu)
906 {
907     int i;
908     CPUARMState *env = &cpu->env;
909 
910     /*
911      * Completely clear out existing QEMU watchpoints and our array, to
912      * avoid possible stale entries following migration load.
913      */
914     cpu_watchpoint_remove_all(CPU(cpu), BP_CPU);
915     memset(env->cpu_watchpoint, 0, sizeof(env->cpu_watchpoint));
916 
917     for (i = 0; i < ARRAY_SIZE(cpu->env.cpu_watchpoint); i++) {
918         hw_watchpoint_update(cpu, i);
919     }
920 }
921 
922 static void dbgwvr_write(CPUARMState *env, const ARMCPRegInfo *ri,
923                          uint64_t value)
924 {
925     ARMCPU *cpu = env_archcpu(env);
926     int i = ri->crm;
927 
928     /*
929      * Bits [1:0] are RES0.
930      *
931      * It is IMPLEMENTATION DEFINED whether [63:49] ([63:53] with FEAT_LVA)
932      * are hardwired to the value of bit [48] ([52] with FEAT_LVA), or if
933      * they contain the value written.  It is CONSTRAINED UNPREDICTABLE
934      * whether the RESS bits are ignored when comparing an address.
935      *
936      * Therefore we are allowed to compare the entire register, which lets
937      * us avoid considering whether or not FEAT_LVA is actually enabled.
938      */
939     value &= ~3ULL;
940 
941     raw_write(env, ri, value);
942     hw_watchpoint_update(cpu, i);
943 }
944 
945 static void dbgwcr_write(CPUARMState *env, const ARMCPRegInfo *ri,
946                          uint64_t value)
947 {
948     ARMCPU *cpu = env_archcpu(env);
949     int i = ri->crm;
950 
951     raw_write(env, ri, value);
952     hw_watchpoint_update(cpu, i);
953 }
954 
955 void hw_breakpoint_update(ARMCPU *cpu, int n)
956 {
957     CPUARMState *env = &cpu->env;
958     uint64_t bvr = env->cp15.dbgbvr[n];
959     uint64_t bcr = env->cp15.dbgbcr[n];
960     vaddr addr;
961     int bt;
962     int flags = BP_CPU;
963 
964     if (env->cpu_breakpoint[n]) {
965         cpu_breakpoint_remove_by_ref(CPU(cpu), env->cpu_breakpoint[n]);
966         env->cpu_breakpoint[n] = NULL;
967     }
968 
969     if (!extract64(bcr, 0, 1)) {
970         /* E bit clear : watchpoint disabled */
971         return;
972     }
973 
974     bt = extract64(bcr, 20, 4);
975 
976     switch (bt) {
977     case 4: /* unlinked address mismatch (reserved if AArch64) */
978     case 5: /* linked address mismatch (reserved if AArch64) */
979         qemu_log_mask(LOG_UNIMP,
980                       "arm: address mismatch breakpoint types not implemented\n");
981         return;
982     case 0: /* unlinked address match */
983     case 1: /* linked address match */
984     {
985         /*
986          * Bits [1:0] are RES0.
987          *
988          * It is IMPLEMENTATION DEFINED whether bits [63:49]
989          * ([63:53] for FEAT_LVA) are hardwired to a copy of the sign bit
990          * of the VA field ([48] or [52] for FEAT_LVA), or whether the
991          * value is read as written.  It is CONSTRAINED UNPREDICTABLE
992          * whether the RESS bits are ignored when comparing an address.
993          * Therefore we are allowed to compare the entire register, which
994          * lets us avoid considering whether FEAT_LVA is actually enabled.
995          *
996          * The BAS field is used to allow setting breakpoints on 16-bit
997          * wide instructions; it is CONSTRAINED UNPREDICTABLE whether
998          * a bp will fire if the addresses covered by the bp and the addresses
999          * covered by the insn overlap but the insn doesn't start at the
1000          * start of the bp address range. We choose to require the insn and
1001          * the bp to have the same address. The constraints on writing to
1002          * BAS enforced in dbgbcr_write mean we have only four cases:
1003          *  0b0000  => no breakpoint
1004          *  0b0011  => breakpoint on addr
1005          *  0b1100  => breakpoint on addr + 2
1006          *  0b1111  => breakpoint on addr
1007          * See also figure D2-3 in the v8 ARM ARM (DDI0487A.c).
1008          */
1009         int bas = extract64(bcr, 5, 4);
1010         addr = bvr & ~3ULL;
1011         if (bas == 0) {
1012             return;
1013         }
1014         if (bas == 0xc) {
1015             addr += 2;
1016         }
1017         break;
1018     }
1019     case 2: /* unlinked context ID match */
1020     case 8: /* unlinked VMID match (reserved if no EL2) */
1021     case 10: /* unlinked context ID and VMID match (reserved if no EL2) */
1022         qemu_log_mask(LOG_UNIMP,
1023                       "arm: unlinked context breakpoint types not implemented\n");
1024         return;
1025     case 9: /* linked VMID match (reserved if no EL2) */
1026     case 11: /* linked context ID and VMID match (reserved if no EL2) */
1027     case 3: /* linked context ID match */
1028     default:
1029         /*
1030          * We must generate no events for Linked context matches (unless
1031          * they are linked to by some other bp/wp, which is handled in
1032          * updates for the linking bp/wp). We choose to also generate no events
1033          * for reserved values.
1034          */
1035         return;
1036     }
1037 
1038     cpu_breakpoint_insert(CPU(cpu), addr, flags, &env->cpu_breakpoint[n]);
1039 }
1040 
1041 void hw_breakpoint_update_all(ARMCPU *cpu)
1042 {
1043     int i;
1044     CPUARMState *env = &cpu->env;
1045 
1046     /*
1047      * Completely clear out existing QEMU breakpoints and our array, to
1048      * avoid possible stale entries following migration load.
1049      */
1050     cpu_breakpoint_remove_all(CPU(cpu), BP_CPU);
1051     memset(env->cpu_breakpoint, 0, sizeof(env->cpu_breakpoint));
1052 
1053     for (i = 0; i < ARRAY_SIZE(cpu->env.cpu_breakpoint); i++) {
1054         hw_breakpoint_update(cpu, i);
1055     }
1056 }
1057 
1058 static void dbgbvr_write(CPUARMState *env, const ARMCPRegInfo *ri,
1059                          uint64_t value)
1060 {
1061     ARMCPU *cpu = env_archcpu(env);
1062     int i = ri->crm;
1063 
1064     raw_write(env, ri, value);
1065     hw_breakpoint_update(cpu, i);
1066 }
1067 
1068 static void dbgbcr_write(CPUARMState *env, const ARMCPRegInfo *ri,
1069                          uint64_t value)
1070 {
1071     ARMCPU *cpu = env_archcpu(env);
1072     int i = ri->crm;
1073 
1074     /*
1075      * BAS[3] is a read-only copy of BAS[2], and BAS[1] a read-only
1076      * copy of BAS[0].
1077      */
1078     value = deposit64(value, 6, 1, extract64(value, 5, 1));
1079     value = deposit64(value, 8, 1, extract64(value, 7, 1));
1080 
1081     raw_write(env, ri, value);
1082     hw_breakpoint_update(cpu, i);
1083 }
1084 
1085 void define_debug_regs(ARMCPU *cpu)
1086 {
1087     /*
1088      * Define v7 and v8 architectural debug registers.
1089      * These are just dummy implementations for now.
1090      */
1091     int i;
1092     int wrps, brps, ctx_cmps;
1093 
1094     /*
1095      * The Arm ARM says DBGDIDR is optional and deprecated if EL1 cannot
1096      * use AArch32.  Given that bit 15 is RES1, if the value is 0 then
1097      * the register must not exist for this cpu.
1098      */
1099     if (cpu->isar.dbgdidr != 0) {
1100         ARMCPRegInfo dbgdidr = {
1101             .name = "DBGDIDR", .cp = 14, .crn = 0, .crm = 0,
1102             .opc1 = 0, .opc2 = 0,
1103             .access = PL0_R, .accessfn = access_tda,
1104             .type = ARM_CP_CONST, .resetvalue = cpu->isar.dbgdidr,
1105         };
1106         define_one_arm_cp_reg(cpu, &dbgdidr);
1107     }
1108 
1109     /*
1110      * DBGDEVID is present in the v7 debug architecture if
1111      * DBGDIDR.DEVID_imp is 1 (bit 15); from v7.1 and on it is
1112      * mandatory (and bit 15 is RES1). DBGDEVID1 and DBGDEVID2 exist
1113      * from v7.1 of the debug architecture. Because no fields have yet
1114      * been defined in DBGDEVID2 (and quite possibly none will ever
1115      * be) we don't define an ARMISARegisters field for it.
1116      * These registers exist only if EL1 can use AArch32, but that
1117      * happens naturally because they are only PL1 accessible anyway.
1118      */
1119     if (extract32(cpu->isar.dbgdidr, 15, 1)) {
1120         ARMCPRegInfo dbgdevid = {
1121             .name = "DBGDEVID",
1122             .cp = 14, .opc1 = 0, .crn = 7, .opc2 = 2, .crn = 7,
1123             .access = PL1_R, .accessfn = access_tda,
1124             .type = ARM_CP_CONST, .resetvalue = cpu->isar.dbgdevid,
1125         };
1126         define_one_arm_cp_reg(cpu, &dbgdevid);
1127     }
1128     if (cpu_isar_feature(aa32_debugv7p1, cpu)) {
1129         ARMCPRegInfo dbgdevid12[] = {
1130             {
1131                 .name = "DBGDEVID1",
1132                 .cp = 14, .opc1 = 0, .crn = 7, .opc2 = 1, .crn = 7,
1133                 .access = PL1_R, .accessfn = access_tda,
1134                 .type = ARM_CP_CONST, .resetvalue = cpu->isar.dbgdevid1,
1135             }, {
1136                 .name = "DBGDEVID2",
1137                 .cp = 14, .opc1 = 0, .crn = 7, .opc2 = 0, .crn = 7,
1138                 .access = PL1_R, .accessfn = access_tda,
1139                 .type = ARM_CP_CONST, .resetvalue = 0,
1140             },
1141         };
1142         define_arm_cp_regs(cpu, dbgdevid12);
1143     }
1144 
1145     brps = arm_num_brps(cpu);
1146     wrps = arm_num_wrps(cpu);
1147     ctx_cmps = arm_num_ctx_cmps(cpu);
1148 
1149     assert(ctx_cmps <= brps);
1150 
1151     define_arm_cp_regs(cpu, debug_cp_reginfo);
1152 
1153     if (arm_feature(&cpu->env, ARM_FEATURE_LPAE)) {
1154         define_arm_cp_regs(cpu, debug_lpae_cp_reginfo);
1155     }
1156 
1157     for (i = 0; i < brps; i++) {
1158         char *dbgbvr_el1_name = g_strdup_printf("DBGBVR%d_EL1", i);
1159         char *dbgbcr_el1_name = g_strdup_printf("DBGBCR%d_EL1", i);
1160         ARMCPRegInfo dbgregs[] = {
1161             { .name = dbgbvr_el1_name, .state = ARM_CP_STATE_BOTH,
1162               .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 0, .crm = i, .opc2 = 4,
1163               .access = PL1_RW, .accessfn = access_tda,
1164               .fgt = FGT_DBGBVRN_EL1,
1165               .fieldoffset = offsetof(CPUARMState, cp15.dbgbvr[i]),
1166               .writefn = dbgbvr_write, .raw_writefn = raw_write
1167             },
1168             { .name = dbgbcr_el1_name, .state = ARM_CP_STATE_BOTH,
1169               .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 0, .crm = i, .opc2 = 5,
1170               .access = PL1_RW, .accessfn = access_tda,
1171               .fgt = FGT_DBGBCRN_EL1,
1172               .fieldoffset = offsetof(CPUARMState, cp15.dbgbcr[i]),
1173               .writefn = dbgbcr_write, .raw_writefn = raw_write
1174             },
1175         };
1176         define_arm_cp_regs(cpu, dbgregs);
1177         g_free(dbgbvr_el1_name);
1178         g_free(dbgbcr_el1_name);
1179     }
1180 
1181     for (i = 0; i < wrps; i++) {
1182         char *dbgwvr_el1_name = g_strdup_printf("DBGWVR%d_EL1", i);
1183         char *dbgwcr_el1_name = g_strdup_printf("DBGWCR%d_EL1", i);
1184         ARMCPRegInfo dbgregs[] = {
1185             { .name = dbgwvr_el1_name, .state = ARM_CP_STATE_BOTH,
1186               .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 0, .crm = i, .opc2 = 6,
1187               .access = PL1_RW, .accessfn = access_tda,
1188               .fgt = FGT_DBGWVRN_EL1,
1189               .fieldoffset = offsetof(CPUARMState, cp15.dbgwvr[i]),
1190               .writefn = dbgwvr_write, .raw_writefn = raw_write
1191             },
1192             { .name = dbgwcr_el1_name, .state = ARM_CP_STATE_BOTH,
1193               .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 0, .crm = i, .opc2 = 7,
1194               .access = PL1_RW, .accessfn = access_tda,
1195               .fgt = FGT_DBGWCRN_EL1,
1196               .fieldoffset = offsetof(CPUARMState, cp15.dbgwcr[i]),
1197               .writefn = dbgwcr_write, .raw_writefn = raw_write
1198             },
1199         };
1200         define_arm_cp_regs(cpu, dbgregs);
1201         g_free(dbgwvr_el1_name);
1202         g_free(dbgwcr_el1_name);
1203     }
1204 }
1205 
1206 #if !defined(CONFIG_USER_ONLY)
1207 
1208 vaddr arm_adjust_watchpoint_address(CPUState *cs, vaddr addr, int len)
1209 {
1210     ARMCPU *cpu = ARM_CPU(cs);
1211     CPUARMState *env = &cpu->env;
1212 
1213     /*
1214      * In BE32 system mode, target memory is stored byteswapped (on a
1215      * little-endian host system), and by the time we reach here (via an
1216      * opcode helper) the addresses of subword accesses have been adjusted
1217      * to account for that, which means that watchpoints will not match.
1218      * Undo the adjustment here.
1219      */
1220     if (arm_sctlr_b(env)) {
1221         if (len == 1) {
1222             addr ^= 3;
1223         } else if (len == 2) {
1224             addr ^= 2;
1225         }
1226     }
1227 
1228     return addr;
1229 }
1230 
1231 #endif
1232