xref: /openbmc/qemu/linux-user/ppc/signal.c (revision 8e3b0cbb)
1 /*
2  *  Emulation of Linux signals
3  *
4  *  Copyright (c) 2003 Fabrice Bellard
5  *
6  *  This program is free software; you can redistribute it and/or modify
7  *  it under the terms of the GNU General Public License as published by
8  *  the Free Software Foundation; either version 2 of the License, or
9  *  (at your option) any later version.
10  *
11  *  This program 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
14  *  GNU General Public License for more details.
15  *
16  *  You should have received a copy of the GNU General Public License
17  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
18  */
19 #include "qemu/osdep.h"
20 #include "qemu.h"
21 #include "user-internals.h"
22 #include "signal-common.h"
23 #include "linux-user/trace.h"
24 
25 /* Size of dummy stack frame allocated when calling signal handler.
26    See arch/powerpc/include/asm/ptrace.h.  */
27 #if defined(TARGET_PPC64)
28 #define SIGNAL_FRAMESIZE 128
29 #else
30 #define SIGNAL_FRAMESIZE 64
31 #endif
32 
33 /* See arch/powerpc/include/asm/ucontext.h.  Only used for 32-bit PPC;
34    on 64-bit PPC, sigcontext and mcontext are one and the same.  */
35 struct target_mcontext {
36     target_ulong mc_gregs[48];
37     /* Includes fpscr.  */
38     uint64_t mc_fregs[33];
39 
40 #if defined(TARGET_PPC64)
41     /* Pointer to the vector regs */
42     target_ulong v_regs;
43     /*
44      * On ppc64, this mcontext structure is naturally *unaligned*,
45      * or rather it is aligned on a 8 bytes boundary but not on
46      * a 16 byte boundary.  This pad fixes it up.  This is why we
47      * cannot use ppc_avr_t, which would force alignment.  This is
48      * also why the vector regs are referenced in the ABI by the
49      * v_regs pointer above so any amount of padding can be added here.
50      */
51     target_ulong pad;
52     /* VSCR and VRSAVE are saved separately.  Also reserve space for VSX. */
53     struct {
54         uint64_t altivec[34 + 16][2];
55     } mc_vregs;
56 #else
57     target_ulong mc_pad[2];
58 
59     /* We need to handle Altivec and SPE at the same time, which no
60        kernel needs to do.  Fortunately, the kernel defines this bit to
61        be Altivec-register-large all the time, rather than trying to
62        twiddle it based on the specific platform.  */
63     union {
64         /* SPE vector registers.  One extra for SPEFSCR.  */
65         uint32_t spe[33];
66         /*
67          * Altivec vector registers.  One extra for VRSAVE.
68          * On ppc32, we are already aligned to 16 bytes.  We could
69          * use ppc_avr_t, but choose to share the same type as ppc64.
70          */
71         uint64_t altivec[33][2];
72     } mc_vregs;
73 #endif
74 };
75 
76 /* See arch/powerpc/include/asm/sigcontext.h.  */
77 struct target_sigcontext {
78     target_ulong _unused[4];
79     int32_t signal;
80 #if defined(TARGET_PPC64)
81     int32_t pad0;
82 #endif
83     target_ulong handler;
84     target_ulong oldmask;
85     target_ulong regs;      /* struct pt_regs __user * */
86 #if defined(TARGET_PPC64)
87     struct target_mcontext mcontext;
88 #endif
89 };
90 
91 /* Indices for target_mcontext.mc_gregs, below.
92    See arch/powerpc/include/asm/ptrace.h for details.  */
93 enum {
94     TARGET_PT_R0 = 0,
95     TARGET_PT_R1 = 1,
96     TARGET_PT_R2 = 2,
97     TARGET_PT_R3 = 3,
98     TARGET_PT_R4 = 4,
99     TARGET_PT_R5 = 5,
100     TARGET_PT_R6 = 6,
101     TARGET_PT_R7 = 7,
102     TARGET_PT_R8 = 8,
103     TARGET_PT_R9 = 9,
104     TARGET_PT_R10 = 10,
105     TARGET_PT_R11 = 11,
106     TARGET_PT_R12 = 12,
107     TARGET_PT_R13 = 13,
108     TARGET_PT_R14 = 14,
109     TARGET_PT_R15 = 15,
110     TARGET_PT_R16 = 16,
111     TARGET_PT_R17 = 17,
112     TARGET_PT_R18 = 18,
113     TARGET_PT_R19 = 19,
114     TARGET_PT_R20 = 20,
115     TARGET_PT_R21 = 21,
116     TARGET_PT_R22 = 22,
117     TARGET_PT_R23 = 23,
118     TARGET_PT_R24 = 24,
119     TARGET_PT_R25 = 25,
120     TARGET_PT_R26 = 26,
121     TARGET_PT_R27 = 27,
122     TARGET_PT_R28 = 28,
123     TARGET_PT_R29 = 29,
124     TARGET_PT_R30 = 30,
125     TARGET_PT_R31 = 31,
126     TARGET_PT_NIP = 32,
127     TARGET_PT_MSR = 33,
128     TARGET_PT_ORIG_R3 = 34,
129     TARGET_PT_CTR = 35,
130     TARGET_PT_LNK = 36,
131     TARGET_PT_XER = 37,
132     TARGET_PT_CCR = 38,
133     /* Yes, there are two registers with #39.  One is 64-bit only.  */
134     TARGET_PT_MQ = 39,
135     TARGET_PT_SOFTE = 39,
136     TARGET_PT_TRAP = 40,
137     TARGET_PT_DAR = 41,
138     TARGET_PT_DSISR = 42,
139     TARGET_PT_RESULT = 43,
140     TARGET_PT_REGS_COUNT = 44
141 };
142 
143 
144 struct target_ucontext {
145     target_ulong tuc_flags;
146     target_ulong tuc_link;    /* ucontext_t __user * */
147     struct target_sigaltstack tuc_stack;
148 #if !defined(TARGET_PPC64)
149     int32_t tuc_pad[7];
150     target_ulong tuc_regs;    /* struct mcontext __user *
151                                 points to uc_mcontext field */
152 #endif
153     target_sigset_t tuc_sigmask;
154 #if defined(TARGET_PPC64)
155     target_sigset_t unused[15]; /* Allow for uc_sigmask growth */
156     struct target_sigcontext tuc_sigcontext;
157 #else
158     int32_t tuc_maskext[30];
159     int32_t tuc_pad2[3];
160     struct target_mcontext tuc_mcontext;
161 #endif
162 };
163 
164 /* See arch/powerpc/kernel/signal_32.c.  */
165 struct target_sigframe {
166     struct target_sigcontext sctx;
167     struct target_mcontext mctx;
168     int32_t abigap[56];
169 };
170 
171 #if defined(TARGET_PPC64)
172 
173 #define TARGET_TRAMP_SIZE 6
174 
175 struct target_rt_sigframe {
176     /* sys_rt_sigreturn requires the ucontext be the first field */
177     struct target_ucontext uc;
178     target_ulong  _unused[2];
179     uint32_t trampoline[TARGET_TRAMP_SIZE];
180     target_ulong pinfo; /* struct siginfo __user * */
181     target_ulong puc; /* void __user * */
182     struct target_siginfo info;
183     /* 64 bit ABI allows for 288 bytes below sp before decrementing it. */
184     char abigap[288];
185 } __attribute__((aligned(16)));
186 
187 #else
188 
189 struct target_rt_sigframe {
190     struct target_siginfo info;
191     struct target_ucontext uc;
192     int32_t abigap[56];
193 };
194 
195 #endif
196 
197 #if defined(TARGET_PPC64)
198 
199 struct target_func_ptr {
200     target_ulong entry;
201     target_ulong toc;
202 };
203 
204 #endif
205 
206 /* See arch/powerpc/kernel/signal.c.  */
207 static target_ulong get_sigframe(struct target_sigaction *ka,
208                                  CPUPPCState *env,
209                                  int frame_size)
210 {
211     target_ulong oldsp;
212 
213     oldsp = target_sigsp(get_sp_from_cpustate(env), ka);
214 
215     return (oldsp - frame_size) & ~0xFUL;
216 }
217 
218 #if TARGET_BIG_ENDIAN == HOST_BIG_ENDIAN
219 #define PPC_VEC_HI      0
220 #define PPC_VEC_LO      1
221 #else
222 #define PPC_VEC_HI      1
223 #define PPC_VEC_LO      0
224 #endif
225 
226 
227 static void save_user_regs(CPUPPCState *env, struct target_mcontext *frame)
228 {
229     target_ulong msr = env->msr;
230     int i;
231     uint32_t ccr = 0;
232 
233     /* In general, the kernel attempts to be intelligent about what it
234        needs to save for Altivec/FP/SPE registers.  We don't care that
235        much, so we just go ahead and save everything.  */
236 
237     /* Save general registers.  */
238     for (i = 0; i < ARRAY_SIZE(env->gpr); i++) {
239         __put_user(env->gpr[i], &frame->mc_gregs[i]);
240     }
241     __put_user(env->nip, &frame->mc_gregs[TARGET_PT_NIP]);
242     __put_user(env->ctr, &frame->mc_gregs[TARGET_PT_CTR]);
243     __put_user(env->lr, &frame->mc_gregs[TARGET_PT_LNK]);
244     __put_user(cpu_read_xer(env), &frame->mc_gregs[TARGET_PT_XER]);
245 
246     for (i = 0; i < ARRAY_SIZE(env->crf); i++) {
247         ccr |= env->crf[i] << (32 - ((i + 1) * 4));
248     }
249     __put_user(ccr, &frame->mc_gregs[TARGET_PT_CCR]);
250 
251     /* Save Altivec registers if necessary.  */
252     if (env->insns_flags & PPC_ALTIVEC) {
253         uint32_t *vrsave;
254         for (i = 0; i < 32; i++) {
255             ppc_avr_t *avr = cpu_avr_ptr(env, i);
256             ppc_avr_t *vreg = (ppc_avr_t *)&frame->mc_vregs.altivec[i];
257 
258             __put_user(avr->u64[PPC_VEC_HI], &vreg->u64[0]);
259             __put_user(avr->u64[PPC_VEC_LO], &vreg->u64[1]);
260         }
261 #if defined(TARGET_PPC64)
262         vrsave = (uint32_t *)&frame->mc_vregs.altivec[33];
263         /* 64-bit needs to put a pointer to the vectors in the frame */
264         __put_user(h2g(frame->mc_vregs.altivec), &frame->v_regs);
265 #else
266         vrsave = (uint32_t *)&frame->mc_vregs.altivec[32];
267 #endif
268         __put_user((uint32_t)env->spr[SPR_VRSAVE], vrsave);
269     }
270 
271 #if defined(TARGET_PPC64)
272     /* Save VSX second halves */
273     if (env->insns_flags2 & PPC2_VSX) {
274         uint64_t *vsregs = (uint64_t *)&frame->mc_vregs.altivec[34];
275         for (i = 0; i < 32; i++) {
276             uint64_t *vsrl = cpu_vsrl_ptr(env, i);
277             __put_user(*vsrl, &vsregs[i]);
278         }
279     }
280 #endif
281 
282     /* Save floating point registers.  */
283     if (env->insns_flags & PPC_FLOAT) {
284         for (i = 0; i < 32; i++) {
285             uint64_t *fpr = cpu_fpr_ptr(env, i);
286             __put_user(*fpr, &frame->mc_fregs[i]);
287         }
288         __put_user((uint64_t) env->fpscr, &frame->mc_fregs[32]);
289     }
290 
291 #if !defined(TARGET_PPC64)
292     /* Save SPE registers.  The kernel only saves the high half.  */
293     if (env->insns_flags & PPC_SPE) {
294         for (i = 0; i < ARRAY_SIZE(env->gprh); i++) {
295             __put_user(env->gprh[i], &frame->mc_vregs.spe[i]);
296         }
297         __put_user(env->spe_fscr, &frame->mc_vregs.spe[32]);
298     }
299 #endif
300 
301     /* Store MSR.  */
302     __put_user(msr, &frame->mc_gregs[TARGET_PT_MSR]);
303 }
304 
305 static void encode_trampoline(int sigret, uint32_t *tramp)
306 {
307     /* Set up the sigreturn trampoline: li r0,sigret; sc.  */
308     __put_user(0x38000000 | sigret, &tramp[0]);
309     __put_user(0x44000002, &tramp[1]);
310 }
311 
312 static void restore_user_regs(CPUPPCState *env,
313                               struct target_mcontext *frame, int sig)
314 {
315     target_ulong save_r2 = 0;
316     target_ulong msr;
317     target_ulong xer;
318     target_ulong ccr;
319 
320     int i;
321 
322     if (!sig) {
323         save_r2 = env->gpr[2];
324     }
325 
326     /* Restore general registers.  */
327     for (i = 0; i < ARRAY_SIZE(env->gpr); i++) {
328         __get_user(env->gpr[i], &frame->mc_gregs[i]);
329     }
330     __get_user(env->nip, &frame->mc_gregs[TARGET_PT_NIP]);
331     __get_user(env->ctr, &frame->mc_gregs[TARGET_PT_CTR]);
332     __get_user(env->lr, &frame->mc_gregs[TARGET_PT_LNK]);
333 
334     __get_user(xer, &frame->mc_gregs[TARGET_PT_XER]);
335     cpu_write_xer(env, xer);
336 
337     __get_user(ccr, &frame->mc_gregs[TARGET_PT_CCR]);
338     for (i = 0; i < ARRAY_SIZE(env->crf); i++) {
339         env->crf[i] = (ccr >> (32 - ((i + 1) * 4))) & 0xf;
340     }
341 
342     if (!sig) {
343         env->gpr[2] = save_r2;
344     }
345     /* Restore MSR.  */
346     __get_user(msr, &frame->mc_gregs[TARGET_PT_MSR]);
347 
348     /* If doing signal return, restore the previous little-endian mode.  */
349     if (sig) {
350         ppc_store_msr(env, ((env->msr & ~(1ull << MSR_LE)) |
351                             (msr & (1ull << MSR_LE))));
352     }
353 
354     /* Restore Altivec registers if necessary.  */
355     if (env->insns_flags & PPC_ALTIVEC) {
356         ppc_avr_t *v_regs;
357         uint32_t *vrsave;
358 #if defined(TARGET_PPC64)
359         uint64_t v_addr;
360         /* 64-bit needs to recover the pointer to the vectors from the frame */
361         __get_user(v_addr, &frame->v_regs);
362         v_regs = g2h(env_cpu(env), v_addr);
363 #else
364         v_regs = (ppc_avr_t *)frame->mc_vregs.altivec;
365 #endif
366         for (i = 0; i < 32; i++) {
367             ppc_avr_t *avr = cpu_avr_ptr(env, i);
368             ppc_avr_t *vreg = &v_regs[i];
369 
370             __get_user(avr->u64[PPC_VEC_HI], &vreg->u64[0]);
371             __get_user(avr->u64[PPC_VEC_LO], &vreg->u64[1]);
372         }
373 #if defined(TARGET_PPC64)
374         vrsave = (uint32_t *)&v_regs[33];
375 #else
376         vrsave = (uint32_t *)&v_regs[32];
377 #endif
378         __get_user(env->spr[SPR_VRSAVE], vrsave);
379     }
380 
381 #if defined(TARGET_PPC64)
382     /* Restore VSX second halves */
383     if (env->insns_flags2 & PPC2_VSX) {
384         uint64_t *vsregs = (uint64_t *)&frame->mc_vregs.altivec[34];
385         for (i = 0; i < 32; i++) {
386             uint64_t *vsrl = cpu_vsrl_ptr(env, i);
387             __get_user(*vsrl, &vsregs[i]);
388         }
389     }
390 #endif
391 
392     /* Restore floating point registers.  */
393     if (env->insns_flags & PPC_FLOAT) {
394         uint64_t fpscr;
395         for (i = 0; i < 32; i++) {
396             uint64_t *fpr = cpu_fpr_ptr(env, i);
397             __get_user(*fpr, &frame->mc_fregs[i]);
398         }
399         __get_user(fpscr, &frame->mc_fregs[32]);
400         env->fpscr = (uint32_t) fpscr;
401     }
402 
403 #if !defined(TARGET_PPC64)
404     /* Save SPE registers.  The kernel only saves the high half.  */
405     if (env->insns_flags & PPC_SPE) {
406         for (i = 0; i < ARRAY_SIZE(env->gprh); i++) {
407             __get_user(env->gprh[i], &frame->mc_vregs.spe[i]);
408         }
409         __get_user(env->spe_fscr, &frame->mc_vregs.spe[32]);
410     }
411 #endif
412 }
413 
414 #if !defined(TARGET_PPC64)
415 void setup_frame(int sig, struct target_sigaction *ka,
416                  target_sigset_t *set, CPUPPCState *env)
417 {
418     struct target_sigframe *frame;
419     struct target_sigcontext *sc;
420     target_ulong frame_addr, newsp;
421     int err = 0;
422 
423     frame_addr = get_sigframe(ka, env, sizeof(*frame));
424     trace_user_setup_frame(env, frame_addr);
425     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 1))
426         goto sigsegv;
427     sc = &frame->sctx;
428 
429     __put_user(ka->_sa_handler, &sc->handler);
430     __put_user(set->sig[0], &sc->oldmask);
431     __put_user(set->sig[1], &sc->_unused[3]);
432     __put_user(h2g(&frame->mctx), &sc->regs);
433     __put_user(sig, &sc->signal);
434 
435     /* Save user regs.  */
436     save_user_regs(env, &frame->mctx);
437 
438     env->lr = default_sigreturn;
439 
440     /* Turn off all fp exceptions.  */
441     env->fpscr = 0;
442 
443     /* Create a stack frame for the caller of the handler.  */
444     newsp = frame_addr - SIGNAL_FRAMESIZE;
445     err |= put_user(env->gpr[1], newsp, target_ulong);
446 
447     if (err)
448         goto sigsegv;
449 
450     /* Set up registers for signal handler.  */
451     env->gpr[1] = newsp;
452     env->gpr[3] = sig;
453     env->gpr[4] = frame_addr + offsetof(struct target_sigframe, sctx);
454 
455     env->nip = (target_ulong) ka->_sa_handler;
456 
457     /* Signal handlers are entered in big-endian mode.  */
458     ppc_store_msr(env, env->msr & ~(1ull << MSR_LE));
459 
460     unlock_user_struct(frame, frame_addr, 1);
461     return;
462 
463 sigsegv:
464     unlock_user_struct(frame, frame_addr, 1);
465     force_sigsegv(sig);
466 }
467 #endif /* !defined(TARGET_PPC64) */
468 
469 void setup_rt_frame(int sig, struct target_sigaction *ka,
470                     target_siginfo_t *info,
471                     target_sigset_t *set, CPUPPCState *env)
472 {
473     struct target_rt_sigframe *rt_sf;
474     struct target_mcontext *mctx = 0;
475     target_ulong rt_sf_addr, newsp = 0;
476     int i, err = 0;
477 #if defined(TARGET_PPC64)
478     struct target_sigcontext *sc = 0;
479     struct image_info *image = ((TaskState *)thread_cpu->opaque)->info;
480 #endif
481 
482     rt_sf_addr = get_sigframe(ka, env, sizeof(*rt_sf));
483     if (!lock_user_struct(VERIFY_WRITE, rt_sf, rt_sf_addr, 1))
484         goto sigsegv;
485 
486     tswap_siginfo(&rt_sf->info, info);
487 
488     __put_user(0, &rt_sf->uc.tuc_flags);
489     __put_user(0, &rt_sf->uc.tuc_link);
490     target_save_altstack(&rt_sf->uc.tuc_stack, env);
491 #if !defined(TARGET_PPC64)
492     __put_user(h2g (&rt_sf->uc.tuc_mcontext),
493                &rt_sf->uc.tuc_regs);
494 #endif
495     for(i = 0; i < TARGET_NSIG_WORDS; i++) {
496         __put_user(set->sig[i], &rt_sf->uc.tuc_sigmask.sig[i]);
497     }
498 
499 #if defined(TARGET_PPC64)
500     mctx = &rt_sf->uc.tuc_sigcontext.mcontext;
501 
502     sc = &rt_sf->uc.tuc_sigcontext;
503     __put_user(h2g(mctx), &sc->regs);
504     __put_user(sig, &sc->signal);
505 #else
506     mctx = &rt_sf->uc.tuc_mcontext;
507 #endif
508 
509     save_user_regs(env, mctx);
510 
511     env->lr = default_rt_sigreturn;
512 
513     /* Turn off all fp exceptions.  */
514     env->fpscr = 0;
515 
516     /* Create a stack frame for the caller of the handler.  */
517     newsp = rt_sf_addr - (SIGNAL_FRAMESIZE + 16);
518     err |= put_user(env->gpr[1], newsp, target_ulong);
519 
520     if (err)
521         goto sigsegv;
522 
523     /* Set up registers for signal handler.  */
524     env->gpr[1] = newsp;
525     env->gpr[3] = (target_ulong) sig;
526     env->gpr[4] = (target_ulong) h2g(&rt_sf->info);
527     env->gpr[5] = (target_ulong) h2g(&rt_sf->uc);
528     env->gpr[6] = (target_ulong) h2g(rt_sf);
529 
530 #if defined(TARGET_PPC64)
531     if (get_ppc64_abi(image) < 2) {
532         /* ELFv1 PPC64 function pointers are pointers to OPD entries. */
533         struct target_func_ptr *handler =
534             (struct target_func_ptr *)g2h(env_cpu(env), ka->_sa_handler);
535         env->nip = tswapl(handler->entry);
536         env->gpr[2] = tswapl(handler->toc);
537     } else {
538         /* ELFv2 PPC64 function pointers are entry points. R12 must also be set. */
539         env->gpr[12] = env->nip = ka->_sa_handler;
540     }
541 #else
542     env->nip = (target_ulong) ka->_sa_handler;
543 #endif
544 
545 #if TARGET_BIG_ENDIAN
546     /* Signal handlers are entered in big-endian mode.  */
547     ppc_store_msr(env, env->msr & ~(1ull << MSR_LE));
548 #else
549     /* Signal handlers are entered in little-endian mode.  */
550     ppc_store_msr(env, env->msr | (1ull << MSR_LE));
551 #endif
552 
553     unlock_user_struct(rt_sf, rt_sf_addr, 1);
554     return;
555 
556 sigsegv:
557     unlock_user_struct(rt_sf, rt_sf_addr, 1);
558     force_sigsegv(sig);
559 
560 }
561 
562 #if !defined(TARGET_PPC64)
563 long do_sigreturn(CPUPPCState *env)
564 {
565     struct target_sigcontext *sc = NULL;
566     struct target_mcontext *sr = NULL;
567     target_ulong sr_addr = 0, sc_addr;
568     sigset_t blocked;
569     target_sigset_t set;
570 
571     sc_addr = env->gpr[1] + SIGNAL_FRAMESIZE;
572     if (!lock_user_struct(VERIFY_READ, sc, sc_addr, 1))
573         goto sigsegv;
574 
575     __get_user(set.sig[0], &sc->oldmask);
576     __get_user(set.sig[1], &sc->_unused[3]);
577 
578     target_to_host_sigset_internal(&blocked, &set);
579     set_sigmask(&blocked);
580 
581     __get_user(sr_addr, &sc->regs);
582     if (!lock_user_struct(VERIFY_READ, sr, sr_addr, 1))
583         goto sigsegv;
584     restore_user_regs(env, sr, 1);
585 
586     unlock_user_struct(sr, sr_addr, 1);
587     unlock_user_struct(sc, sc_addr, 1);
588     return -QEMU_ESIGRETURN;
589 
590 sigsegv:
591     unlock_user_struct(sr, sr_addr, 1);
592     unlock_user_struct(sc, sc_addr, 1);
593     force_sig(TARGET_SIGSEGV);
594     return -QEMU_ESIGRETURN;
595 }
596 #endif /* !defined(TARGET_PPC64) */
597 
598 /* See arch/powerpc/kernel/signal_32.c.  */
599 static int do_setcontext(struct target_ucontext *ucp, CPUPPCState *env, int sig)
600 {
601     struct target_mcontext *mcp;
602     target_ulong mcp_addr;
603     sigset_t blocked;
604     target_sigset_t set;
605 
606     if (copy_from_user(&set, h2g(ucp) + offsetof(struct target_ucontext, tuc_sigmask),
607                        sizeof (set)))
608         return 1;
609 
610 #if defined(TARGET_PPC64)
611     mcp_addr = h2g(ucp) +
612         offsetof(struct target_ucontext, tuc_sigcontext.mcontext);
613 #else
614     __get_user(mcp_addr, &ucp->tuc_regs);
615 #endif
616 
617     if (!lock_user_struct(VERIFY_READ, mcp, mcp_addr, 1))
618         return 1;
619 
620     target_to_host_sigset_internal(&blocked, &set);
621     set_sigmask(&blocked);
622     restore_user_regs(env, mcp, sig);
623 
624     unlock_user_struct(mcp, mcp_addr, 1);
625     return 0;
626 }
627 
628 long do_rt_sigreturn(CPUPPCState *env)
629 {
630     struct target_rt_sigframe *rt_sf = NULL;
631     target_ulong rt_sf_addr;
632 
633     rt_sf_addr = env->gpr[1] + SIGNAL_FRAMESIZE + 16;
634     if (!lock_user_struct(VERIFY_READ, rt_sf, rt_sf_addr, 1))
635         goto sigsegv;
636 
637     if (do_setcontext(&rt_sf->uc, env, 1))
638         goto sigsegv;
639 
640     target_restore_altstack(&rt_sf->uc.tuc_stack, env);
641 
642     unlock_user_struct(rt_sf, rt_sf_addr, 1);
643     return -QEMU_ESIGRETURN;
644 
645 sigsegv:
646     unlock_user_struct(rt_sf, rt_sf_addr, 1);
647     force_sig(TARGET_SIGSEGV);
648     return -QEMU_ESIGRETURN;
649 }
650 
651 /* This syscall implements {get,set,swap}context for userland.  */
652 abi_long do_swapcontext(CPUArchState *env, abi_ulong uold_ctx,
653                         abi_ulong unew_ctx, abi_long ctx_size)
654 {
655     struct target_ucontext *uctx;
656     struct target_mcontext *mctx;
657 
658     /* For ppc32, ctx_size is "reserved for future use".
659      * For ppc64, we do not yet support the VSX extension.
660      */
661     if (ctx_size < sizeof(struct target_ucontext)) {
662         return -TARGET_EINVAL;
663     }
664 
665     if (uold_ctx) {
666         TaskState *ts = (TaskState *)thread_cpu->opaque;
667 
668         if (!lock_user_struct(VERIFY_WRITE, uctx, uold_ctx, 1)) {
669             return -TARGET_EFAULT;
670         }
671 
672 #ifdef TARGET_PPC64
673         mctx = &uctx->tuc_sigcontext.mcontext;
674 #else
675         /* ??? The kernel aligns the pointer down here into padding, but
676          * in setup_rt_frame we don't.  Be self-compatible for now.
677          */
678         mctx = &uctx->tuc_mcontext;
679         __put_user(h2g(mctx), &uctx->tuc_regs);
680 #endif
681 
682         save_user_regs(env, mctx);
683         host_to_target_sigset(&uctx->tuc_sigmask, &ts->signal_mask);
684 
685         unlock_user_struct(uctx, uold_ctx, 1);
686     }
687 
688     if (unew_ctx) {
689         int err;
690 
691         if (!lock_user_struct(VERIFY_READ, uctx, unew_ctx, 1)) {
692             return -TARGET_EFAULT;
693         }
694         err = do_setcontext(uctx, env, 0);
695         unlock_user_struct(uctx, unew_ctx, 1);
696 
697         if (err) {
698             /* We cannot return to a partially updated context.  */
699             force_sig(TARGET_SIGSEGV);
700         }
701         return -QEMU_ESIGRETURN;
702     }
703 
704     return 0;
705 }
706 
707 void setup_sigtramp(abi_ulong sigtramp_page)
708 {
709     uint32_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 2 * 8, 0);
710     assert(tramp != NULL);
711 
712 #ifdef TARGET_ARCH_HAS_SETUP_FRAME
713     default_sigreturn = sigtramp_page;
714     encode_trampoline(TARGET_NR_sigreturn, tramp + 0);
715 #endif
716 
717     default_rt_sigreturn = sigtramp_page + 8;
718     encode_trampoline(TARGET_NR_rt_sigreturn, tramp + 2);
719 
720     unlock_user(tramp, sigtramp_page, 2 * 8);
721 }
722