xref: /openbmc/qemu/accel/tcg/user-exec.c (revision fc664254)
1 /*
2  *  User emulator execution
3  *
4  *  Copyright (c) 2003-2005 Fabrice Bellard
5  *
6  * This library is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * This library is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
18  */
19 #include "qemu/osdep.h"
20 #include "hw/core/tcg-cpu-ops.h"
21 #include "disas/disas.h"
22 #include "exec/exec-all.h"
23 #include "tcg/tcg.h"
24 #include "qemu/bitops.h"
25 #include "exec/cpu_ldst.h"
26 #include "exec/translate-all.h"
27 #include "exec/helper-proto.h"
28 #include "qemu/atomic128.h"
29 #include "trace/trace-root.h"
30 #include "internal.h"
31 
32 #undef EAX
33 #undef ECX
34 #undef EDX
35 #undef EBX
36 #undef ESP
37 #undef EBP
38 #undef ESI
39 #undef EDI
40 #undef EIP
41 #ifdef __linux__
42 #include <sys/ucontext.h>
43 #endif
44 
45 __thread uintptr_t helper_retaddr;
46 
47 //#define DEBUG_SIGNAL
48 
49 /* exit the current TB from a signal handler. The host registers are
50    restored in a state compatible with the CPU emulator
51  */
52 static void QEMU_NORETURN cpu_exit_tb_from_sighandler(CPUState *cpu,
53                                                       sigset_t *old_set)
54 {
55     /* XXX: use siglongjmp ? */
56     sigprocmask(SIG_SETMASK, old_set, NULL);
57     cpu_loop_exit_noexc(cpu);
58 }
59 
60 /* 'pc' is the host PC at which the exception was raised. 'address' is
61    the effective address of the memory exception. 'is_write' is 1 if a
62    write caused the exception and otherwise 0'. 'old_set' is the
63    signal set which should be restored */
64 static inline int handle_cpu_signal(uintptr_t pc, siginfo_t *info,
65                                     int is_write, sigset_t *old_set)
66 {
67     CPUState *cpu = current_cpu;
68     CPUClass *cc;
69     unsigned long address = (unsigned long)info->si_addr;
70     MMUAccessType access_type = is_write ? MMU_DATA_STORE : MMU_DATA_LOAD;
71 
72     switch (helper_retaddr) {
73     default:
74         /*
75          * Fault during host memory operation within a helper function.
76          * The helper's host return address, saved here, gives us a
77          * pointer into the generated code that will unwind to the
78          * correct guest pc.
79          */
80         pc = helper_retaddr;
81         break;
82 
83     case 0:
84         /*
85          * Fault during host memory operation within generated code.
86          * (Or, a unrelated bug within qemu, but we can't tell from here).
87          *
88          * We take the host pc from the signal frame.  However, we cannot
89          * use that value directly.  Within cpu_restore_state_from_tb, we
90          * assume PC comes from GETPC(), as used by the helper functions,
91          * so we adjust the address by -GETPC_ADJ to form an address that
92          * is within the call insn, so that the address does not accidentally
93          * match the beginning of the next guest insn.  However, when the
94          * pc comes from the signal frame it points to the actual faulting
95          * host memory insn and not the return from a call insn.
96          *
97          * Therefore, adjust to compensate for what will be done later
98          * by cpu_restore_state_from_tb.
99          */
100         pc += GETPC_ADJ;
101         break;
102 
103     case 1:
104         /*
105          * Fault during host read for translation, or loosely, "execution".
106          *
107          * The guest pc is already pointing to the start of the TB for which
108          * code is being generated.  If the guest translator manages the
109          * page crossings correctly, this is exactly the correct address
110          * (and if the translator doesn't handle page boundaries correctly
111          * there's little we can do about that here).  Therefore, do not
112          * trigger the unwinder.
113          *
114          * Like tb_gen_code, release the memory lock before cpu_loop_exit.
115          */
116         pc = 0;
117         access_type = MMU_INST_FETCH;
118         mmap_unlock();
119         break;
120     }
121 
122     /* For synchronous signals we expect to be coming from the vCPU
123      * thread (so current_cpu should be valid) and either from running
124      * code or during translation which can fault as we cross pages.
125      *
126      * If neither is true then something has gone wrong and we should
127      * abort rather than try and restart the vCPU execution.
128      */
129     if (!cpu || !cpu->running) {
130         printf("qemu:%s received signal outside vCPU context @ pc=0x%"
131                PRIxPTR "\n",  __func__, pc);
132         abort();
133     }
134 
135 #if defined(DEBUG_SIGNAL)
136     printf("qemu: SIGSEGV pc=0x%08lx address=%08lx w=%d oldset=0x%08lx\n",
137            pc, address, is_write, *(unsigned long *)old_set);
138 #endif
139     /* XXX: locking issue */
140     /* Note that it is important that we don't call page_unprotect() unless
141      * this is really a "write to nonwriteable page" fault, because
142      * page_unprotect() assumes that if it is called for an access to
143      * a page that's writeable this means we had two threads racing and
144      * another thread got there first and already made the page writeable;
145      * so we will retry the access. If we were to call page_unprotect()
146      * for some other kind of fault that should really be passed to the
147      * guest, we'd end up in an infinite loop of retrying the faulting
148      * access.
149      */
150     if (is_write && info->si_signo == SIGSEGV && info->si_code == SEGV_ACCERR &&
151         h2g_valid(address)) {
152         switch (page_unprotect(h2g(address), pc)) {
153         case 0:
154             /* Fault not caused by a page marked unwritable to protect
155              * cached translations, must be the guest binary's problem.
156              */
157             break;
158         case 1:
159             /* Fault caused by protection of cached translation; TBs
160              * invalidated, so resume execution.  Retain helper_retaddr
161              * for a possible second fault.
162              */
163             return 1;
164         case 2:
165             /* Fault caused by protection of cached translation, and the
166              * currently executing TB was modified and must be exited
167              * immediately.  Clear helper_retaddr for next execution.
168              */
169             clear_helper_retaddr();
170             cpu_exit_tb_from_sighandler(cpu, old_set);
171             /* NORETURN */
172 
173         default:
174             g_assert_not_reached();
175         }
176     }
177 
178     /* Convert forcefully to guest address space, invalid addresses
179        are still valid segv ones */
180     address = h2g_nocheck(address);
181 
182     /*
183      * There is no way the target can handle this other than raising
184      * an exception.  Undo signal and retaddr state prior to longjmp.
185      */
186     sigprocmask(SIG_SETMASK, old_set, NULL);
187     clear_helper_retaddr();
188 
189     cc = CPU_GET_CLASS(cpu);
190     cc->tcg_ops->tlb_fill(cpu, address, 0, access_type,
191                           MMU_USER_IDX, false, pc);
192     g_assert_not_reached();
193 }
194 
195 static int probe_access_internal(CPUArchState *env, target_ulong addr,
196                                  int fault_size, MMUAccessType access_type,
197                                  bool nonfault, uintptr_t ra)
198 {
199     int flags;
200 
201     switch (access_type) {
202     case MMU_DATA_STORE:
203         flags = PAGE_WRITE;
204         break;
205     case MMU_DATA_LOAD:
206         flags = PAGE_READ;
207         break;
208     case MMU_INST_FETCH:
209         flags = PAGE_EXEC;
210         break;
211     default:
212         g_assert_not_reached();
213     }
214 
215     if (!guest_addr_valid_untagged(addr) ||
216         page_check_range(addr, 1, flags) < 0) {
217         if (nonfault) {
218             return TLB_INVALID_MASK;
219         } else {
220             CPUState *cpu = env_cpu(env);
221             CPUClass *cc = CPU_GET_CLASS(cpu);
222             cc->tcg_ops->tlb_fill(cpu, addr, fault_size, access_type,
223                                   MMU_USER_IDX, false, ra);
224             g_assert_not_reached();
225         }
226     }
227     return 0;
228 }
229 
230 int probe_access_flags(CPUArchState *env, target_ulong addr,
231                        MMUAccessType access_type, int mmu_idx,
232                        bool nonfault, void **phost, uintptr_t ra)
233 {
234     int flags;
235 
236     flags = probe_access_internal(env, addr, 0, access_type, nonfault, ra);
237     *phost = flags ? NULL : g2h(env_cpu(env), addr);
238     return flags;
239 }
240 
241 void *probe_access(CPUArchState *env, target_ulong addr, int size,
242                    MMUAccessType access_type, int mmu_idx, uintptr_t ra)
243 {
244     int flags;
245 
246     g_assert(-(addr | TARGET_PAGE_MASK) >= size);
247     flags = probe_access_internal(env, addr, size, access_type, false, ra);
248     g_assert(flags == 0);
249 
250     return size ? g2h(env_cpu(env), addr) : NULL;
251 }
252 
253 #if defined(__i386__)
254 
255 #if defined(__NetBSD__)
256 #include <ucontext.h>
257 #include <machine/trap.h>
258 
259 #define EIP_sig(context)     ((context)->uc_mcontext.__gregs[_REG_EIP])
260 #define TRAP_sig(context)    ((context)->uc_mcontext.__gregs[_REG_TRAPNO])
261 #define ERROR_sig(context)   ((context)->uc_mcontext.__gregs[_REG_ERR])
262 #define MASK_sig(context)    ((context)->uc_sigmask)
263 #define PAGE_FAULT_TRAP      T_PAGEFLT
264 #elif defined(__FreeBSD__) || defined(__DragonFly__)
265 #include <ucontext.h>
266 #include <machine/trap.h>
267 
268 #define EIP_sig(context)  (*((unsigned long *)&(context)->uc_mcontext.mc_eip))
269 #define TRAP_sig(context)    ((context)->uc_mcontext.mc_trapno)
270 #define ERROR_sig(context)   ((context)->uc_mcontext.mc_err)
271 #define MASK_sig(context)    ((context)->uc_sigmask)
272 #define PAGE_FAULT_TRAP      T_PAGEFLT
273 #elif defined(__OpenBSD__)
274 #include <machine/trap.h>
275 #define EIP_sig(context)     ((context)->sc_eip)
276 #define TRAP_sig(context)    ((context)->sc_trapno)
277 #define ERROR_sig(context)   ((context)->sc_err)
278 #define MASK_sig(context)    ((context)->sc_mask)
279 #define PAGE_FAULT_TRAP      T_PAGEFLT
280 #else
281 #define EIP_sig(context)     ((context)->uc_mcontext.gregs[REG_EIP])
282 #define TRAP_sig(context)    ((context)->uc_mcontext.gregs[REG_TRAPNO])
283 #define ERROR_sig(context)   ((context)->uc_mcontext.gregs[REG_ERR])
284 #define MASK_sig(context)    ((context)->uc_sigmask)
285 #define PAGE_FAULT_TRAP      0xe
286 #endif
287 
288 int cpu_signal_handler(int host_signum, void *pinfo,
289                        void *puc)
290 {
291     siginfo_t *info = pinfo;
292 #if defined(__NetBSD__) || defined(__FreeBSD__) || defined(__DragonFly__)
293     ucontext_t *uc = puc;
294 #elif defined(__OpenBSD__)
295     struct sigcontext *uc = puc;
296 #else
297     ucontext_t *uc = puc;
298 #endif
299     unsigned long pc;
300     int trapno;
301 
302 #ifndef REG_EIP
303 /* for glibc 2.1 */
304 #define REG_EIP    EIP
305 #define REG_ERR    ERR
306 #define REG_TRAPNO TRAPNO
307 #endif
308     pc = EIP_sig(uc);
309     trapno = TRAP_sig(uc);
310     return handle_cpu_signal(pc, info,
311                              trapno == PAGE_FAULT_TRAP ?
312                              (ERROR_sig(uc) >> 1) & 1 : 0,
313                              &MASK_sig(uc));
314 }
315 
316 #elif defined(__x86_64__)
317 
318 #ifdef __NetBSD__
319 #include <machine/trap.h>
320 #define PC_sig(context)       _UC_MACHINE_PC(context)
321 #define TRAP_sig(context)     ((context)->uc_mcontext.__gregs[_REG_TRAPNO])
322 #define ERROR_sig(context)    ((context)->uc_mcontext.__gregs[_REG_ERR])
323 #define MASK_sig(context)     ((context)->uc_sigmask)
324 #define PAGE_FAULT_TRAP       T_PAGEFLT
325 #elif defined(__OpenBSD__)
326 #include <machine/trap.h>
327 #define PC_sig(context)       ((context)->sc_rip)
328 #define TRAP_sig(context)     ((context)->sc_trapno)
329 #define ERROR_sig(context)    ((context)->sc_err)
330 #define MASK_sig(context)     ((context)->sc_mask)
331 #define PAGE_FAULT_TRAP       T_PAGEFLT
332 #elif defined(__FreeBSD__) || defined(__DragonFly__)
333 #include <ucontext.h>
334 #include <machine/trap.h>
335 
336 #define PC_sig(context)  (*((unsigned long *)&(context)->uc_mcontext.mc_rip))
337 #define TRAP_sig(context)     ((context)->uc_mcontext.mc_trapno)
338 #define ERROR_sig(context)    ((context)->uc_mcontext.mc_err)
339 #define MASK_sig(context)     ((context)->uc_sigmask)
340 #define PAGE_FAULT_TRAP       T_PAGEFLT
341 #else
342 #define PC_sig(context)       ((context)->uc_mcontext.gregs[REG_RIP])
343 #define TRAP_sig(context)     ((context)->uc_mcontext.gregs[REG_TRAPNO])
344 #define ERROR_sig(context)    ((context)->uc_mcontext.gregs[REG_ERR])
345 #define MASK_sig(context)     ((context)->uc_sigmask)
346 #define PAGE_FAULT_TRAP       0xe
347 #endif
348 
349 int cpu_signal_handler(int host_signum, void *pinfo,
350                        void *puc)
351 {
352     siginfo_t *info = pinfo;
353     unsigned long pc;
354 #if defined(__NetBSD__) || defined(__FreeBSD__) || defined(__DragonFly__)
355     ucontext_t *uc = puc;
356 #elif defined(__OpenBSD__)
357     struct sigcontext *uc = puc;
358 #else
359     ucontext_t *uc = puc;
360 #endif
361 
362     pc = PC_sig(uc);
363     return handle_cpu_signal(pc, info,
364                              TRAP_sig(uc) == PAGE_FAULT_TRAP ?
365                              (ERROR_sig(uc) >> 1) & 1 : 0,
366                              &MASK_sig(uc));
367 }
368 
369 #elif defined(_ARCH_PPC)
370 
371 /***********************************************************************
372  * signal context platform-specific definitions
373  * From Wine
374  */
375 #ifdef linux
376 /* All Registers access - only for local access */
377 #define REG_sig(reg_name, context)              \
378     ((context)->uc_mcontext.regs->reg_name)
379 /* Gpr Registers access  */
380 #define GPR_sig(reg_num, context)              REG_sig(gpr[reg_num], context)
381 /* Program counter */
382 #define IAR_sig(context)                       REG_sig(nip, context)
383 /* Machine State Register (Supervisor) */
384 #define MSR_sig(context)                       REG_sig(msr, context)
385 /* Count register */
386 #define CTR_sig(context)                       REG_sig(ctr, context)
387 /* User's integer exception register */
388 #define XER_sig(context)                       REG_sig(xer, context)
389 /* Link register */
390 #define LR_sig(context)                        REG_sig(link, context)
391 /* Condition register */
392 #define CR_sig(context)                        REG_sig(ccr, context)
393 
394 /* Float Registers access  */
395 #define FLOAT_sig(reg_num, context)                                     \
396     (((double *)((char *)((context)->uc_mcontext.regs + 48 * 4)))[reg_num])
397 #define FPSCR_sig(context) \
398     (*(int *)((char *)((context)->uc_mcontext.regs + (48 + 32 * 2) * 4)))
399 /* Exception Registers access */
400 #define DAR_sig(context)                       REG_sig(dar, context)
401 #define DSISR_sig(context)                     REG_sig(dsisr, context)
402 #define TRAP_sig(context)                      REG_sig(trap, context)
403 #endif /* linux */
404 
405 #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
406 #include <ucontext.h>
407 #define IAR_sig(context)               ((context)->uc_mcontext.mc_srr0)
408 #define MSR_sig(context)               ((context)->uc_mcontext.mc_srr1)
409 #define CTR_sig(context)               ((context)->uc_mcontext.mc_ctr)
410 #define XER_sig(context)               ((context)->uc_mcontext.mc_xer)
411 #define LR_sig(context)                ((context)->uc_mcontext.mc_lr)
412 #define CR_sig(context)                ((context)->uc_mcontext.mc_cr)
413 /* Exception Registers access */
414 #define DAR_sig(context)               ((context)->uc_mcontext.mc_dar)
415 #define DSISR_sig(context)             ((context)->uc_mcontext.mc_dsisr)
416 #define TRAP_sig(context)              ((context)->uc_mcontext.mc_exc)
417 #endif /* __FreeBSD__|| __FreeBSD_kernel__ */
418 
419 int cpu_signal_handler(int host_signum, void *pinfo,
420                        void *puc)
421 {
422     siginfo_t *info = pinfo;
423 #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
424     ucontext_t *uc = puc;
425 #else
426     ucontext_t *uc = puc;
427 #endif
428     unsigned long pc;
429     int is_write;
430 
431     pc = IAR_sig(uc);
432     is_write = 0;
433 #if 0
434     /* ppc 4xx case */
435     if (DSISR_sig(uc) & 0x00800000) {
436         is_write = 1;
437     }
438 #else
439     if (TRAP_sig(uc) != 0x400 && (DSISR_sig(uc) & 0x02000000)) {
440         is_write = 1;
441     }
442 #endif
443     return handle_cpu_signal(pc, info, is_write, &uc->uc_sigmask);
444 }
445 
446 #elif defined(__alpha__)
447 
448 int cpu_signal_handler(int host_signum, void *pinfo,
449                            void *puc)
450 {
451     siginfo_t *info = pinfo;
452     ucontext_t *uc = puc;
453     uint32_t *pc = uc->uc_mcontext.sc_pc;
454     uint32_t insn = *pc;
455     int is_write = 0;
456 
457     /* XXX: need kernel patch to get write flag faster */
458     switch (insn >> 26) {
459     case 0x0d: /* stw */
460     case 0x0e: /* stb */
461     case 0x0f: /* stq_u */
462     case 0x24: /* stf */
463     case 0x25: /* stg */
464     case 0x26: /* sts */
465     case 0x27: /* stt */
466     case 0x2c: /* stl */
467     case 0x2d: /* stq */
468     case 0x2e: /* stl_c */
469     case 0x2f: /* stq_c */
470         is_write = 1;
471     }
472 
473     return handle_cpu_signal(pc, info, is_write, &uc->uc_sigmask);
474 }
475 #elif defined(__sparc__)
476 
477 int cpu_signal_handler(int host_signum, void *pinfo,
478                        void *puc)
479 {
480     siginfo_t *info = pinfo;
481     int is_write;
482     uint32_t insn;
483 #if !defined(__arch64__) || defined(CONFIG_SOLARIS)
484     uint32_t *regs = (uint32_t *)(info + 1);
485     void *sigmask = (regs + 20);
486     /* XXX: is there a standard glibc define ? */
487     unsigned long pc = regs[1];
488 #else
489 #ifdef __linux__
490     struct sigcontext *sc = puc;
491     unsigned long pc = sc->sigc_regs.tpc;
492     void *sigmask = (void *)sc->sigc_mask;
493 #elif defined(__OpenBSD__)
494     struct sigcontext *uc = puc;
495     unsigned long pc = uc->sc_pc;
496     void *sigmask = (void *)(long)uc->sc_mask;
497 #elif defined(__NetBSD__)
498     ucontext_t *uc = puc;
499     unsigned long pc = _UC_MACHINE_PC(uc);
500     void *sigmask = (void *)&uc->uc_sigmask;
501 #endif
502 #endif
503 
504     /* XXX: need kernel patch to get write flag faster */
505     is_write = 0;
506     insn = *(uint32_t *)pc;
507     if ((insn >> 30) == 3) {
508         switch ((insn >> 19) & 0x3f) {
509         case 0x05: /* stb */
510         case 0x15: /* stba */
511         case 0x06: /* sth */
512         case 0x16: /* stha */
513         case 0x04: /* st */
514         case 0x14: /* sta */
515         case 0x07: /* std */
516         case 0x17: /* stda */
517         case 0x0e: /* stx */
518         case 0x1e: /* stxa */
519         case 0x24: /* stf */
520         case 0x34: /* stfa */
521         case 0x27: /* stdf */
522         case 0x37: /* stdfa */
523         case 0x26: /* stqf */
524         case 0x36: /* stqfa */
525         case 0x25: /* stfsr */
526         case 0x3c: /* casa */
527         case 0x3e: /* casxa */
528             is_write = 1;
529             break;
530         }
531     }
532     return handle_cpu_signal(pc, info, is_write, sigmask);
533 }
534 
535 #elif defined(__arm__)
536 
537 #if defined(__NetBSD__)
538 #include <ucontext.h>
539 #include <sys/siginfo.h>
540 #endif
541 
542 int cpu_signal_handler(int host_signum, void *pinfo,
543                        void *puc)
544 {
545     siginfo_t *info = pinfo;
546 #if defined(__NetBSD__)
547     ucontext_t *uc = puc;
548     siginfo_t *si = pinfo;
549 #else
550     ucontext_t *uc = puc;
551 #endif
552     unsigned long pc;
553     uint32_t fsr;
554     int is_write;
555 
556 #if defined(__NetBSD__)
557     pc = uc->uc_mcontext.__gregs[_REG_R15];
558 #elif defined(__GLIBC__) && (__GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ <= 3))
559     pc = uc->uc_mcontext.gregs[R15];
560 #else
561     pc = uc->uc_mcontext.arm_pc;
562 #endif
563 
564 #ifdef __NetBSD__
565     fsr = si->si_trap;
566 #else
567     fsr = uc->uc_mcontext.error_code;
568 #endif
569     /*
570      * In the FSR, bit 11 is WnR, assuming a v6 or
571      * later processor.  On v5 we will always report
572      * this as a read, which will fail later.
573      */
574     is_write = extract32(fsr, 11, 1);
575     return handle_cpu_signal(pc, info, is_write, &uc->uc_sigmask);
576 }
577 
578 #elif defined(__aarch64__)
579 
580 #if defined(__NetBSD__)
581 
582 #include <ucontext.h>
583 #include <sys/siginfo.h>
584 
585 int cpu_signal_handler(int host_signum, void *pinfo, void *puc)
586 {
587     ucontext_t *uc = puc;
588     siginfo_t *si = pinfo;
589     unsigned long pc;
590     int is_write;
591     uint32_t esr;
592 
593     pc = uc->uc_mcontext.__gregs[_REG_PC];
594     esr = si->si_trap;
595 
596     /*
597      * siginfo_t::si_trap is the ESR value, for data aborts ESR.EC
598      * is 0b10010x: then bit 6 is the WnR bit
599      */
600     is_write = extract32(esr, 27, 5) == 0x12 && extract32(esr, 6, 1) == 1;
601     return handle_cpu_signal(pc, si, is_write, &uc->uc_sigmask);
602 }
603 
604 #else
605 
606 #ifndef ESR_MAGIC
607 /* Pre-3.16 kernel headers don't have these, so provide fallback definitions */
608 #define ESR_MAGIC 0x45535201
609 struct esr_context {
610     struct _aarch64_ctx head;
611     uint64_t esr;
612 };
613 #endif
614 
615 static inline struct _aarch64_ctx *first_ctx(ucontext_t *uc)
616 {
617     return (struct _aarch64_ctx *)&uc->uc_mcontext.__reserved;
618 }
619 
620 static inline struct _aarch64_ctx *next_ctx(struct _aarch64_ctx *hdr)
621 {
622     return (struct _aarch64_ctx *)((char *)hdr + hdr->size);
623 }
624 
625 int cpu_signal_handler(int host_signum, void *pinfo, void *puc)
626 {
627     siginfo_t *info = pinfo;
628     ucontext_t *uc = puc;
629     uintptr_t pc = uc->uc_mcontext.pc;
630     bool is_write;
631     struct _aarch64_ctx *hdr;
632     struct esr_context const *esrctx = NULL;
633 
634     /* Find the esr_context, which has the WnR bit in it */
635     for (hdr = first_ctx(uc); hdr->magic; hdr = next_ctx(hdr)) {
636         if (hdr->magic == ESR_MAGIC) {
637             esrctx = (struct esr_context const *)hdr;
638             break;
639         }
640     }
641 
642     if (esrctx) {
643         /* For data aborts ESR.EC is 0b10010x: then bit 6 is the WnR bit */
644         uint64_t esr = esrctx->esr;
645         is_write = extract32(esr, 27, 5) == 0x12 && extract32(esr, 6, 1) == 1;
646     } else {
647         /*
648          * Fall back to parsing instructions; will only be needed
649          * for really ancient (pre-3.16) kernels.
650          */
651         uint32_t insn = *(uint32_t *)pc;
652 
653         is_write = ((insn & 0xbfff0000) == 0x0c000000   /* C3.3.1 */
654                     || (insn & 0xbfe00000) == 0x0c800000   /* C3.3.2 */
655                     || (insn & 0xbfdf0000) == 0x0d000000   /* C3.3.3 */
656                     || (insn & 0xbfc00000) == 0x0d800000   /* C3.3.4 */
657                     || (insn & 0x3f400000) == 0x08000000   /* C3.3.6 */
658                     || (insn & 0x3bc00000) == 0x39000000   /* C3.3.13 */
659                     || (insn & 0x3fc00000) == 0x3d800000   /* ... 128bit */
660                     /* Ignore bits 10, 11 & 21, controlling indexing.  */
661                     || (insn & 0x3bc00000) == 0x38000000   /* C3.3.8-12 */
662                     || (insn & 0x3fe00000) == 0x3c800000   /* ... 128bit */
663                     /* Ignore bits 23 & 24, controlling indexing.  */
664                     || (insn & 0x3a400000) == 0x28000000); /* C3.3.7,14-16 */
665     }
666     return handle_cpu_signal(pc, info, is_write, &uc->uc_sigmask);
667 }
668 #endif
669 
670 #elif defined(__s390__)
671 
672 int cpu_signal_handler(int host_signum, void *pinfo,
673                        void *puc)
674 {
675     siginfo_t *info = pinfo;
676     ucontext_t *uc = puc;
677     unsigned long pc;
678     uint16_t *pinsn;
679     int is_write = 0;
680 
681     pc = uc->uc_mcontext.psw.addr;
682 
683     /*
684      * ??? On linux, the non-rt signal handler has 4 (!) arguments instead
685      * of the normal 2 arguments.  The 4th argument contains the "Translation-
686      * Exception Identification for DAT Exceptions" from the hardware (aka
687      * "int_parm_long"), which does in fact contain the is_write value.
688      * The rt signal handler, as far as I can tell, does not give this value
689      * at all.  Not that we could get to it from here even if it were.
690      * So fall back to parsing instructions.  Treat read-modify-write ones as
691      * writes, which is not fully correct, but for tracking self-modifying code
692      * this is better than treating them as reads.  Checking si_addr page flags
693      * might be a viable improvement, albeit a racy one.
694      */
695     /* ??? This is not even close to complete.  */
696     pinsn = (uint16_t *)pc;
697     switch (pinsn[0] >> 8) {
698     case 0x50: /* ST */
699     case 0x42: /* STC */
700     case 0x40: /* STH */
701     case 0xba: /* CS */
702     case 0xbb: /* CDS */
703         is_write = 1;
704         break;
705     case 0xc4: /* RIL format insns */
706         switch (pinsn[0] & 0xf) {
707         case 0xf: /* STRL */
708         case 0xb: /* STGRL */
709         case 0x7: /* STHRL */
710             is_write = 1;
711         }
712         break;
713     case 0xc8: /* SSF format insns */
714         switch (pinsn[0] & 0xf) {
715         case 0x2: /* CSST */
716             is_write = 1;
717         }
718         break;
719     case 0xe3: /* RXY format insns */
720         switch (pinsn[2] & 0xff) {
721         case 0x50: /* STY */
722         case 0x24: /* STG */
723         case 0x72: /* STCY */
724         case 0x70: /* STHY */
725         case 0x8e: /* STPQ */
726         case 0x3f: /* STRVH */
727         case 0x3e: /* STRV */
728         case 0x2f: /* STRVG */
729             is_write = 1;
730         }
731         break;
732     case 0xeb: /* RSY format insns */
733         switch (pinsn[2] & 0xff) {
734         case 0x14: /* CSY */
735         case 0x30: /* CSG */
736         case 0x31: /* CDSY */
737         case 0x3e: /* CDSG */
738         case 0xe4: /* LANG */
739         case 0xe6: /* LAOG */
740         case 0xe7: /* LAXG */
741         case 0xe8: /* LAAG */
742         case 0xea: /* LAALG */
743         case 0xf4: /* LAN */
744         case 0xf6: /* LAO */
745         case 0xf7: /* LAX */
746         case 0xfa: /* LAAL */
747         case 0xf8: /* LAA */
748             is_write = 1;
749         }
750         break;
751     }
752 
753     return handle_cpu_signal(pc, info, is_write, &uc->uc_sigmask);
754 }
755 
756 #elif defined(__mips__)
757 
758 #if defined(__misp16) || defined(__mips_micromips)
759 #error "Unsupported encoding"
760 #endif
761 
762 int cpu_signal_handler(int host_signum, void *pinfo,
763                        void *puc)
764 {
765     siginfo_t *info = pinfo;
766     ucontext_t *uc = puc;
767     uintptr_t pc = uc->uc_mcontext.pc;
768     uint32_t insn = *(uint32_t *)pc;
769     int is_write = 0;
770 
771     /* Detect all store instructions at program counter. */
772     switch((insn >> 26) & 077) {
773     case 050: /* SB */
774     case 051: /* SH */
775     case 052: /* SWL */
776     case 053: /* SW */
777     case 054: /* SDL */
778     case 055: /* SDR */
779     case 056: /* SWR */
780     case 070: /* SC */
781     case 071: /* SWC1 */
782     case 074: /* SCD */
783     case 075: /* SDC1 */
784     case 077: /* SD */
785 #if !defined(__mips_isa_rev) || __mips_isa_rev < 6
786     case 072: /* SWC2 */
787     case 076: /* SDC2 */
788 #endif
789         is_write = 1;
790         break;
791     case 023: /* COP1X */
792         /* Required in all versions of MIPS64 since
793            MIPS64r1 and subsequent versions of MIPS32r2. */
794         switch (insn & 077) {
795         case 010: /* SWXC1 */
796         case 011: /* SDXC1 */
797         case 015: /* SUXC1 */
798             is_write = 1;
799         }
800         break;
801     }
802 
803     return handle_cpu_signal(pc, info, is_write, &uc->uc_sigmask);
804 }
805 
806 #elif defined(__riscv)
807 
808 int cpu_signal_handler(int host_signum, void *pinfo,
809                        void *puc)
810 {
811     siginfo_t *info = pinfo;
812     ucontext_t *uc = puc;
813     greg_t pc = uc->uc_mcontext.__gregs[REG_PC];
814     uint32_t insn = *(uint32_t *)pc;
815     int is_write = 0;
816 
817     /* Detect store by reading the instruction at the program
818        counter. Note: we currently only generate 32-bit
819        instructions so we thus only detect 32-bit stores */
820     switch (((insn >> 0) & 0b11)) {
821     case 3:
822         switch (((insn >> 2) & 0b11111)) {
823         case 8:
824             switch (((insn >> 12) & 0b111)) {
825             case 0: /* sb */
826             case 1: /* sh */
827             case 2: /* sw */
828             case 3: /* sd */
829             case 4: /* sq */
830                 is_write = 1;
831                 break;
832             default:
833                 break;
834             }
835             break;
836         case 9:
837             switch (((insn >> 12) & 0b111)) {
838             case 2: /* fsw */
839             case 3: /* fsd */
840             case 4: /* fsq */
841                 is_write = 1;
842                 break;
843             default:
844                 break;
845             }
846             break;
847         default:
848             break;
849         }
850     }
851 
852     /* Check for compressed instructions */
853     switch (((insn >> 13) & 0b111)) {
854     case 7:
855         switch (insn & 0b11) {
856         case 0: /*c.sd */
857         case 2: /* c.sdsp */
858             is_write = 1;
859             break;
860         default:
861             break;
862         }
863         break;
864     case 6:
865         switch (insn & 0b11) {
866         case 0: /* c.sw */
867         case 3: /* c.swsp */
868             is_write = 1;
869             break;
870         default:
871             break;
872         }
873         break;
874     default:
875         break;
876     }
877 
878     return handle_cpu_signal(pc, info, is_write, &uc->uc_sigmask);
879 }
880 
881 #else
882 
883 #error host CPU specific signal handler needed
884 
885 #endif
886 
887 /* The softmmu versions of these helpers are in cputlb.c.  */
888 
889 /*
890  * Verify that we have passed the correct MemOp to the correct function.
891  *
892  * We could present one function to target code, and dispatch based on
893  * the MemOp, but so far we have worked hard to avoid an indirect function
894  * call along the memory path.
895  */
896 static void validate_memop(MemOpIdx oi, MemOp expected)
897 {
898 #ifdef CONFIG_DEBUG_TCG
899     MemOp have = get_memop(oi) & (MO_SIZE | MO_BSWAP);
900     assert(have == expected);
901 #endif
902 }
903 
904 static void *cpu_mmu_lookup(CPUArchState *env, target_ulong addr,
905                             MemOpIdx oi, uintptr_t ra, MMUAccessType type)
906 {
907     void *ret;
908 
909     /* TODO: Enforce guest required alignment.  */
910 
911     ret = g2h(env_cpu(env), addr);
912     set_helper_retaddr(ra);
913     return ret;
914 }
915 
916 uint8_t cpu_ldb_mmu(CPUArchState *env, abi_ptr addr,
917                     MemOpIdx oi, uintptr_t ra)
918 {
919     void *haddr;
920     uint8_t ret;
921 
922     validate_memop(oi, MO_UB);
923     trace_guest_ld_before_exec(env_cpu(env), addr, oi);
924     haddr = cpu_mmu_lookup(env, addr, oi, ra, MMU_DATA_LOAD);
925     ret = ldub_p(haddr);
926     clear_helper_retaddr();
927     qemu_plugin_vcpu_mem_cb(env_cpu(env), addr, oi, QEMU_PLUGIN_MEM_R);
928     return ret;
929 }
930 
931 uint16_t cpu_ldw_be_mmu(CPUArchState *env, abi_ptr addr,
932                         MemOpIdx oi, uintptr_t ra)
933 {
934     void *haddr;
935     uint16_t ret;
936 
937     validate_memop(oi, MO_BEUW);
938     trace_guest_ld_before_exec(env_cpu(env), addr, oi);
939     haddr = cpu_mmu_lookup(env, addr, oi, ra, MMU_DATA_LOAD);
940     ret = lduw_be_p(haddr);
941     clear_helper_retaddr();
942     qemu_plugin_vcpu_mem_cb(env_cpu(env), addr, oi, QEMU_PLUGIN_MEM_R);
943     return ret;
944 }
945 
946 uint32_t cpu_ldl_be_mmu(CPUArchState *env, abi_ptr addr,
947                         MemOpIdx oi, uintptr_t ra)
948 {
949     void *haddr;
950     uint32_t ret;
951 
952     validate_memop(oi, MO_BEUL);
953     trace_guest_ld_before_exec(env_cpu(env), addr, oi);
954     haddr = cpu_mmu_lookup(env, addr, oi, ra, MMU_DATA_LOAD);
955     ret = ldl_be_p(haddr);
956     clear_helper_retaddr();
957     qemu_plugin_vcpu_mem_cb(env_cpu(env), addr, oi, QEMU_PLUGIN_MEM_R);
958     return ret;
959 }
960 
961 uint64_t cpu_ldq_be_mmu(CPUArchState *env, abi_ptr addr,
962                         MemOpIdx oi, uintptr_t ra)
963 {
964     void *haddr;
965     uint64_t ret;
966 
967     validate_memop(oi, MO_BEQ);
968     trace_guest_ld_before_exec(env_cpu(env), addr, oi);
969     haddr = cpu_mmu_lookup(env, addr, oi, ra, MMU_DATA_LOAD);
970     ret = ldq_be_p(haddr);
971     clear_helper_retaddr();
972     qemu_plugin_vcpu_mem_cb(env_cpu(env), addr, oi, QEMU_PLUGIN_MEM_R);
973     return ret;
974 }
975 
976 uint16_t cpu_ldw_le_mmu(CPUArchState *env, abi_ptr addr,
977                         MemOpIdx oi, uintptr_t ra)
978 {
979     void *haddr;
980     uint16_t ret;
981 
982     validate_memop(oi, MO_LEUW);
983     trace_guest_ld_before_exec(env_cpu(env), addr, oi);
984     haddr = cpu_mmu_lookup(env, addr, oi, ra, MMU_DATA_LOAD);
985     ret = lduw_le_p(haddr);
986     clear_helper_retaddr();
987     qemu_plugin_vcpu_mem_cb(env_cpu(env), addr, oi, QEMU_PLUGIN_MEM_R);
988     return ret;
989 }
990 
991 uint32_t cpu_ldl_le_mmu(CPUArchState *env, abi_ptr addr,
992                         MemOpIdx oi, uintptr_t ra)
993 {
994     void *haddr;
995     uint32_t ret;
996 
997     validate_memop(oi, MO_LEUL);
998     trace_guest_ld_before_exec(env_cpu(env), addr, oi);
999     haddr = cpu_mmu_lookup(env, addr, oi, ra, MMU_DATA_LOAD);
1000     ret = ldl_le_p(haddr);
1001     clear_helper_retaddr();
1002     qemu_plugin_vcpu_mem_cb(env_cpu(env), addr, oi, QEMU_PLUGIN_MEM_R);
1003     return ret;
1004 }
1005 
1006 uint64_t cpu_ldq_le_mmu(CPUArchState *env, abi_ptr addr,
1007                         MemOpIdx oi, uintptr_t ra)
1008 {
1009     void *haddr;
1010     uint64_t ret;
1011 
1012     validate_memop(oi, MO_LEQ);
1013     trace_guest_ld_before_exec(env_cpu(env), addr, oi);
1014     haddr = cpu_mmu_lookup(env, addr, oi, ra, MMU_DATA_LOAD);
1015     ret = ldq_le_p(haddr);
1016     clear_helper_retaddr();
1017     qemu_plugin_vcpu_mem_cb(env_cpu(env), addr, oi, QEMU_PLUGIN_MEM_R);
1018     return ret;
1019 }
1020 
1021 void cpu_stb_mmu(CPUArchState *env, abi_ptr addr, uint8_t val,
1022                  MemOpIdx oi, uintptr_t ra)
1023 {
1024     void *haddr;
1025 
1026     validate_memop(oi, MO_UB);
1027     trace_guest_st_before_exec(env_cpu(env), addr, oi);
1028     haddr = cpu_mmu_lookup(env, addr, oi, ra, MMU_DATA_STORE);
1029     stb_p(haddr, val);
1030     clear_helper_retaddr();
1031     qemu_plugin_vcpu_mem_cb(env_cpu(env), addr, oi, QEMU_PLUGIN_MEM_W);
1032 }
1033 
1034 void cpu_stw_be_mmu(CPUArchState *env, abi_ptr addr, uint16_t val,
1035                     MemOpIdx oi, uintptr_t ra)
1036 {
1037     void *haddr;
1038 
1039     validate_memop(oi, MO_BEUW);
1040     trace_guest_st_before_exec(env_cpu(env), addr, oi);
1041     haddr = cpu_mmu_lookup(env, addr, oi, ra, MMU_DATA_STORE);
1042     stw_be_p(haddr, val);
1043     clear_helper_retaddr();
1044     qemu_plugin_vcpu_mem_cb(env_cpu(env), addr, oi, QEMU_PLUGIN_MEM_W);
1045 }
1046 
1047 void cpu_stl_be_mmu(CPUArchState *env, abi_ptr addr, uint32_t val,
1048                     MemOpIdx oi, uintptr_t ra)
1049 {
1050     void *haddr;
1051 
1052     validate_memop(oi, MO_BEUL);
1053     trace_guest_st_before_exec(env_cpu(env), addr, oi);
1054     haddr = cpu_mmu_lookup(env, addr, oi, ra, MMU_DATA_STORE);
1055     stl_be_p(haddr, val);
1056     clear_helper_retaddr();
1057     qemu_plugin_vcpu_mem_cb(env_cpu(env), addr, oi, QEMU_PLUGIN_MEM_W);
1058 }
1059 
1060 void cpu_stq_be_mmu(CPUArchState *env, abi_ptr addr, uint64_t val,
1061                     MemOpIdx oi, uintptr_t ra)
1062 {
1063     void *haddr;
1064 
1065     validate_memop(oi, MO_BEQ);
1066     trace_guest_st_before_exec(env_cpu(env), addr, oi);
1067     haddr = cpu_mmu_lookup(env, addr, oi, ra, MMU_DATA_STORE);
1068     stq_be_p(haddr, val);
1069     clear_helper_retaddr();
1070     qemu_plugin_vcpu_mem_cb(env_cpu(env), addr, oi, QEMU_PLUGIN_MEM_W);
1071 }
1072 
1073 void cpu_stw_le_mmu(CPUArchState *env, abi_ptr addr, uint16_t val,
1074                     MemOpIdx oi, uintptr_t ra)
1075 {
1076     void *haddr;
1077 
1078     validate_memop(oi, MO_LEUW);
1079     trace_guest_st_before_exec(env_cpu(env), addr, oi);
1080     haddr = cpu_mmu_lookup(env, addr, oi, ra, MMU_DATA_STORE);
1081     stw_le_p(haddr, val);
1082     clear_helper_retaddr();
1083     qemu_plugin_vcpu_mem_cb(env_cpu(env), addr, oi, QEMU_PLUGIN_MEM_W);
1084 }
1085 
1086 void cpu_stl_le_mmu(CPUArchState *env, abi_ptr addr, uint32_t val,
1087                     MemOpIdx oi, uintptr_t ra)
1088 {
1089     void *haddr;
1090 
1091     validate_memop(oi, MO_LEUL);
1092     trace_guest_st_before_exec(env_cpu(env), addr, oi);
1093     haddr = cpu_mmu_lookup(env, addr, oi, ra, MMU_DATA_STORE);
1094     stl_le_p(haddr, val);
1095     clear_helper_retaddr();
1096     qemu_plugin_vcpu_mem_cb(env_cpu(env), addr, oi, QEMU_PLUGIN_MEM_W);
1097 }
1098 
1099 void cpu_stq_le_mmu(CPUArchState *env, abi_ptr addr, uint64_t val,
1100                     MemOpIdx oi, uintptr_t ra)
1101 {
1102     void *haddr;
1103 
1104     validate_memop(oi, MO_LEQ);
1105     trace_guest_st_before_exec(env_cpu(env), addr, oi);
1106     haddr = cpu_mmu_lookup(env, addr, oi, ra, MMU_DATA_STORE);
1107     stq_le_p(haddr, val);
1108     clear_helper_retaddr();
1109     qemu_plugin_vcpu_mem_cb(env_cpu(env), addr, oi, QEMU_PLUGIN_MEM_W);
1110 }
1111 
1112 uint32_t cpu_ldub_code(CPUArchState *env, abi_ptr ptr)
1113 {
1114     uint32_t ret;
1115 
1116     set_helper_retaddr(1);
1117     ret = ldub_p(g2h_untagged(ptr));
1118     clear_helper_retaddr();
1119     return ret;
1120 }
1121 
1122 uint32_t cpu_lduw_code(CPUArchState *env, abi_ptr ptr)
1123 {
1124     uint32_t ret;
1125 
1126     set_helper_retaddr(1);
1127     ret = lduw_p(g2h_untagged(ptr));
1128     clear_helper_retaddr();
1129     return ret;
1130 }
1131 
1132 uint32_t cpu_ldl_code(CPUArchState *env, abi_ptr ptr)
1133 {
1134     uint32_t ret;
1135 
1136     set_helper_retaddr(1);
1137     ret = ldl_p(g2h_untagged(ptr));
1138     clear_helper_retaddr();
1139     return ret;
1140 }
1141 
1142 uint64_t cpu_ldq_code(CPUArchState *env, abi_ptr ptr)
1143 {
1144     uint64_t ret;
1145 
1146     set_helper_retaddr(1);
1147     ret = ldq_p(g2h_untagged(ptr));
1148     clear_helper_retaddr();
1149     return ret;
1150 }
1151 
1152 #include "ldst_common.c.inc"
1153 
1154 /*
1155  * Do not allow unaligned operations to proceed.  Return the host address.
1156  *
1157  * @prot may be PAGE_READ, PAGE_WRITE, or PAGE_READ|PAGE_WRITE.
1158  */
1159 static void *atomic_mmu_lookup(CPUArchState *env, target_ulong addr,
1160                                MemOpIdx oi, int size, int prot,
1161                                uintptr_t retaddr)
1162 {
1163     /* Enforce qemu required alignment.  */
1164     if (unlikely(addr & (size - 1))) {
1165         cpu_loop_exit_atomic(env_cpu(env), retaddr);
1166     }
1167     void *ret = g2h(env_cpu(env), addr);
1168     set_helper_retaddr(retaddr);
1169     return ret;
1170 }
1171 
1172 #include "atomic_common.c.inc"
1173 
1174 /*
1175  * First set of functions passes in OI and RETADDR.
1176  * This makes them callable from other helpers.
1177  */
1178 
1179 #define ATOMIC_NAME(X) \
1180     glue(glue(glue(cpu_atomic_ ## X, SUFFIX), END), _mmu)
1181 #define ATOMIC_MMU_CLEANUP do { clear_helper_retaddr(); } while (0)
1182 #define ATOMIC_MMU_IDX MMU_USER_IDX
1183 
1184 #define DATA_SIZE 1
1185 #include "atomic_template.h"
1186 
1187 #define DATA_SIZE 2
1188 #include "atomic_template.h"
1189 
1190 #define DATA_SIZE 4
1191 #include "atomic_template.h"
1192 
1193 #ifdef CONFIG_ATOMIC64
1194 #define DATA_SIZE 8
1195 #include "atomic_template.h"
1196 #endif
1197 
1198 #if HAVE_ATOMIC128 || HAVE_CMPXCHG128
1199 #define DATA_SIZE 16
1200 #include "atomic_template.h"
1201 #endif
1202