xref: /openbmc/qemu/linux-user/ppc/signal.c (revision b91a0fa7)
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 ((defined(TARGET_WORDS_BIGENDIAN) && defined(HOST_WORDS_BIGENDIAN)) || \
219      (!defined(HOST_WORDS_BIGENDIAN) && !defined(TARGET_WORDS_BIGENDIAN)))
220 #define PPC_VEC_HI      0
221 #define PPC_VEC_LO      1
222 #else
223 #define PPC_VEC_HI      1
224 #define PPC_VEC_LO      0
225 #endif
226 
227 
228 static void save_user_regs(CPUPPCState *env, struct target_mcontext *frame)
229 {
230     target_ulong msr = env->msr;
231     int i;
232     target_ulong ccr = 0;
233 
234     /* In general, the kernel attempts to be intelligent about what it
235        needs to save for Altivec/FP/SPE registers.  We don't care that
236        much, so we just go ahead and save everything.  */
237 
238     /* Save general registers.  */
239     for (i = 0; i < ARRAY_SIZE(env->gpr); i++) {
240         __put_user(env->gpr[i], &frame->mc_gregs[i]);
241     }
242     __put_user(env->nip, &frame->mc_gregs[TARGET_PT_NIP]);
243     __put_user(env->ctr, &frame->mc_gregs[TARGET_PT_CTR]);
244     __put_user(env->lr, &frame->mc_gregs[TARGET_PT_LNK]);
245     __put_user(cpu_read_xer(env), &frame->mc_gregs[TARGET_PT_XER]);
246 
247     for (i = 0; i < ARRAY_SIZE(env->crf); i++) {
248         ccr |= env->crf[i] << (32 - ((i + 1) * 4));
249     }
250     __put_user(ccr, &frame->mc_gregs[TARGET_PT_CCR]);
251 
252     /* Save Altivec registers if necessary.  */
253     if (env->insns_flags & PPC_ALTIVEC) {
254         uint32_t *vrsave;
255         for (i = 0; i < 32; i++) {
256             ppc_avr_t *avr = cpu_avr_ptr(env, i);
257             ppc_avr_t *vreg = (ppc_avr_t *)&frame->mc_vregs.altivec[i];
258 
259             __put_user(avr->u64[PPC_VEC_HI], &vreg->u64[0]);
260             __put_user(avr->u64[PPC_VEC_LO], &vreg->u64[1]);
261         }
262 #if defined(TARGET_PPC64)
263         vrsave = (uint32_t *)&frame->mc_vregs.altivec[33];
264         /* 64-bit needs to put a pointer to the vectors in the frame */
265         __put_user(h2g(frame->mc_vregs.altivec), &frame->v_regs);
266 #else
267         vrsave = (uint32_t *)&frame->mc_vregs.altivec[32];
268 #endif
269         __put_user((uint32_t)env->spr[SPR_VRSAVE], vrsave);
270     }
271 
272 #if defined(TARGET_PPC64)
273     /* Save VSX second halves */
274     if (env->insns_flags2 & PPC2_VSX) {
275         uint64_t *vsregs = (uint64_t *)&frame->mc_vregs.altivec[34];
276         for (i = 0; i < 32; i++) {
277             uint64_t *vsrl = cpu_vsrl_ptr(env, i);
278             __put_user(*vsrl, &vsregs[i]);
279         }
280     }
281 #endif
282 
283     /* Save floating point registers.  */
284     if (env->insns_flags & PPC_FLOAT) {
285         for (i = 0; i < 32; i++) {
286             uint64_t *fpr = cpu_fpr_ptr(env, i);
287             __put_user(*fpr, &frame->mc_fregs[i]);
288         }
289         __put_user((uint64_t) env->fpscr, &frame->mc_fregs[32]);
290     }
291 
292 #if !defined(TARGET_PPC64)
293     /* Save SPE registers.  The kernel only saves the high half.  */
294     if (env->insns_flags & PPC_SPE) {
295         for (i = 0; i < ARRAY_SIZE(env->gprh); i++) {
296             __put_user(env->gprh[i], &frame->mc_vregs.spe[i]);
297         }
298         __put_user(env->spe_fscr, &frame->mc_vregs.spe[32]);
299     }
300 #endif
301 
302     /* Store MSR.  */
303     __put_user(msr, &frame->mc_gregs[TARGET_PT_MSR]);
304 }
305 
306 static void encode_trampoline(int sigret, uint32_t *tramp)
307 {
308     /* Set up the sigreturn trampoline: li r0,sigret; sc.  */
309     __put_user(0x38000000 | sigret, &tramp[0]);
310     __put_user(0x44000002, &tramp[1]);
311 }
312 
313 static void restore_user_regs(CPUPPCState *env,
314                               struct target_mcontext *frame, int sig)
315 {
316     target_ulong save_r2 = 0;
317     target_ulong msr;
318     target_ulong xer;
319     target_ulong ccr;
320 
321     int i;
322 
323     if (!sig) {
324         save_r2 = env->gpr[2];
325     }
326 
327     /* Restore general registers.  */
328     for (i = 0; i < ARRAY_SIZE(env->gpr); i++) {
329         __get_user(env->gpr[i], &frame->mc_gregs[i]);
330     }
331     __get_user(env->nip, &frame->mc_gregs[TARGET_PT_NIP]);
332     __get_user(env->ctr, &frame->mc_gregs[TARGET_PT_CTR]);
333     __get_user(env->lr, &frame->mc_gregs[TARGET_PT_LNK]);
334 
335     __get_user(xer, &frame->mc_gregs[TARGET_PT_XER]);
336     cpu_write_xer(env, xer);
337 
338     __get_user(ccr, &frame->mc_gregs[TARGET_PT_CCR]);
339     for (i = 0; i < ARRAY_SIZE(env->crf); i++) {
340         env->crf[i] = (ccr >> (32 - ((i + 1) * 4))) & 0xf;
341     }
342 
343     if (!sig) {
344         env->gpr[2] = save_r2;
345     }
346     /* Restore MSR.  */
347     __get_user(msr, &frame->mc_gregs[TARGET_PT_MSR]);
348 
349     /* If doing signal return, restore the previous little-endian mode.  */
350     if (sig) {
351         ppc_store_msr(env, ((env->msr & ~(1ull << MSR_LE)) |
352                             (msr & (1ull << MSR_LE))));
353     }
354 
355     /* Restore Altivec registers if necessary.  */
356     if (env->insns_flags & PPC_ALTIVEC) {
357         ppc_avr_t *v_regs;
358         uint32_t *vrsave;
359 #if defined(TARGET_PPC64)
360         uint64_t v_addr;
361         /* 64-bit needs to recover the pointer to the vectors from the frame */
362         __get_user(v_addr, &frame->v_regs);
363         v_regs = g2h(env_cpu(env), v_addr);
364 #else
365         v_regs = (ppc_avr_t *)frame->mc_vregs.altivec;
366 #endif
367         for (i = 0; i < 32; i++) {
368             ppc_avr_t *avr = cpu_avr_ptr(env, i);
369             ppc_avr_t *vreg = &v_regs[i];
370 
371             __get_user(avr->u64[PPC_VEC_HI], &vreg->u64[0]);
372             __get_user(avr->u64[PPC_VEC_LO], &vreg->u64[1]);
373         }
374 #if defined(TARGET_PPC64)
375         vrsave = (uint32_t *)&v_regs[33];
376 #else
377         vrsave = (uint32_t *)&v_regs[32];
378 #endif
379         __get_user(env->spr[SPR_VRSAVE], vrsave);
380     }
381 
382 #if defined(TARGET_PPC64)
383     /* Restore VSX second halves */
384     if (env->insns_flags2 & PPC2_VSX) {
385         uint64_t *vsregs = (uint64_t *)&frame->mc_vregs.altivec[34];
386         for (i = 0; i < 32; i++) {
387             uint64_t *vsrl = cpu_vsrl_ptr(env, i);
388             __get_user(*vsrl, &vsregs[i]);
389         }
390     }
391 #endif
392 
393     /* Restore floating point registers.  */
394     if (env->insns_flags & PPC_FLOAT) {
395         uint64_t fpscr;
396         for (i = 0; i < 32; i++) {
397             uint64_t *fpr = cpu_fpr_ptr(env, i);
398             __get_user(*fpr, &frame->mc_fregs[i]);
399         }
400         __get_user(fpscr, &frame->mc_fregs[32]);
401         env->fpscr = (uint32_t) fpscr;
402     }
403 
404 #if !defined(TARGET_PPC64)
405     /* Save SPE registers.  The kernel only saves the high half.  */
406     if (env->insns_flags & PPC_SPE) {
407         for (i = 0; i < ARRAY_SIZE(env->gprh); i++) {
408             __get_user(env->gprh[i], &frame->mc_vregs.spe[i]);
409         }
410         __get_user(env->spe_fscr, &frame->mc_vregs.spe[32]);
411     }
412 #endif
413 }
414 
415 #if !defined(TARGET_PPC64)
416 void setup_frame(int sig, struct target_sigaction *ka,
417                  target_sigset_t *set, CPUPPCState *env)
418 {
419     struct target_sigframe *frame;
420     struct target_sigcontext *sc;
421     target_ulong frame_addr, newsp;
422     int err = 0;
423 
424     frame_addr = get_sigframe(ka, env, sizeof(*frame));
425     trace_user_setup_frame(env, frame_addr);
426     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 1))
427         goto sigsegv;
428     sc = &frame->sctx;
429 
430     __put_user(ka->_sa_handler, &sc->handler);
431     __put_user(set->sig[0], &sc->oldmask);
432     __put_user(set->sig[1], &sc->_unused[3]);
433     __put_user(h2g(&frame->mctx), &sc->regs);
434     __put_user(sig, &sc->signal);
435 
436     /* Save user regs.  */
437     save_user_regs(env, &frame->mctx);
438 
439     env->lr = default_sigreturn;
440 
441     /* Turn off all fp exceptions.  */
442     env->fpscr = 0;
443 
444     /* Create a stack frame for the caller of the handler.  */
445     newsp = frame_addr - SIGNAL_FRAMESIZE;
446     err |= put_user(env->gpr[1], newsp, target_ulong);
447 
448     if (err)
449         goto sigsegv;
450 
451     /* Set up registers for signal handler.  */
452     env->gpr[1] = newsp;
453     env->gpr[3] = sig;
454     env->gpr[4] = frame_addr + offsetof(struct target_sigframe, sctx);
455 
456     env->nip = (target_ulong) ka->_sa_handler;
457 
458     /* Signal handlers are entered in big-endian mode.  */
459     ppc_store_msr(env, env->msr & ~(1ull << MSR_LE));
460 
461     unlock_user_struct(frame, frame_addr, 1);
462     return;
463 
464 sigsegv:
465     unlock_user_struct(frame, frame_addr, 1);
466     force_sigsegv(sig);
467 }
468 #endif /* !defined(TARGET_PPC64) */
469 
470 void setup_rt_frame(int sig, struct target_sigaction *ka,
471                     target_siginfo_t *info,
472                     target_sigset_t *set, CPUPPCState *env)
473 {
474     struct target_rt_sigframe *rt_sf;
475     struct target_mcontext *mctx = 0;
476     target_ulong rt_sf_addr, newsp = 0;
477     int i, err = 0;
478 #if defined(TARGET_PPC64)
479     struct target_sigcontext *sc = 0;
480 #if !defined(TARGET_ABI32)
481     struct image_info *image = ((TaskState *)thread_cpu->opaque)->info;
482 #endif
483 #endif
484 
485     rt_sf_addr = get_sigframe(ka, env, sizeof(*rt_sf));
486     if (!lock_user_struct(VERIFY_WRITE, rt_sf, rt_sf_addr, 1))
487         goto sigsegv;
488 
489     tswap_siginfo(&rt_sf->info, info);
490 
491     __put_user(0, &rt_sf->uc.tuc_flags);
492     __put_user(0, &rt_sf->uc.tuc_link);
493     target_save_altstack(&rt_sf->uc.tuc_stack, env);
494 #if !defined(TARGET_PPC64)
495     __put_user(h2g (&rt_sf->uc.tuc_mcontext),
496                &rt_sf->uc.tuc_regs);
497 #endif
498     for(i = 0; i < TARGET_NSIG_WORDS; i++) {
499         __put_user(set->sig[i], &rt_sf->uc.tuc_sigmask.sig[i]);
500     }
501 
502 #if defined(TARGET_PPC64)
503     mctx = &rt_sf->uc.tuc_sigcontext.mcontext;
504 
505     sc = &rt_sf->uc.tuc_sigcontext;
506     __put_user(h2g(mctx), &sc->regs);
507     __put_user(sig, &sc->signal);
508 #else
509     mctx = &rt_sf->uc.tuc_mcontext;
510 #endif
511 
512     save_user_regs(env, mctx);
513 
514     env->lr = default_rt_sigreturn;
515 
516     /* Turn off all fp exceptions.  */
517     env->fpscr = 0;
518 
519     /* Create a stack frame for the caller of the handler.  */
520     newsp = rt_sf_addr - (SIGNAL_FRAMESIZE + 16);
521     err |= put_user(env->gpr[1], newsp, target_ulong);
522 
523     if (err)
524         goto sigsegv;
525 
526     /* Set up registers for signal handler.  */
527     env->gpr[1] = newsp;
528     env->gpr[3] = (target_ulong) sig;
529     env->gpr[4] = (target_ulong) h2g(&rt_sf->info);
530     env->gpr[5] = (target_ulong) h2g(&rt_sf->uc);
531     env->gpr[6] = (target_ulong) h2g(rt_sf);
532 
533 #if defined(TARGET_PPC64) && !defined(TARGET_ABI32)
534     if (get_ppc64_abi(image) < 2) {
535         /* ELFv1 PPC64 function pointers are pointers to OPD entries. */
536         struct target_func_ptr *handler =
537             (struct target_func_ptr *)g2h(env_cpu(env), ka->_sa_handler);
538         env->nip = tswapl(handler->entry);
539         env->gpr[2] = tswapl(handler->toc);
540     } else {
541         /* ELFv2 PPC64 function pointers are entry points. R12 must also be set. */
542         env->gpr[12] = env->nip = ka->_sa_handler;
543     }
544 #else
545     env->nip = (target_ulong) ka->_sa_handler;
546 #endif
547 
548 #ifdef TARGET_WORDS_BIGENDIAN
549     /* Signal handlers are entered in big-endian mode.  */
550     ppc_store_msr(env, env->msr & ~(1ull << MSR_LE));
551 #else
552     /* Signal handlers are entered in little-endian mode.  */
553     ppc_store_msr(env, env->msr | (1ull << MSR_LE));
554 #endif
555 
556     unlock_user_struct(rt_sf, rt_sf_addr, 1);
557     return;
558 
559 sigsegv:
560     unlock_user_struct(rt_sf, rt_sf_addr, 1);
561     force_sigsegv(sig);
562 
563 }
564 
565 #if !defined(TARGET_PPC64) || defined(TARGET_ABI32)
566 long do_sigreturn(CPUPPCState *env)
567 {
568     struct target_sigcontext *sc = NULL;
569     struct target_mcontext *sr = NULL;
570     target_ulong sr_addr = 0, sc_addr;
571     sigset_t blocked;
572     target_sigset_t set;
573 
574     sc_addr = env->gpr[1] + SIGNAL_FRAMESIZE;
575     if (!lock_user_struct(VERIFY_READ, sc, sc_addr, 1))
576         goto sigsegv;
577 
578 #if defined(TARGET_PPC64)
579     set.sig[0] = sc->oldmask + ((uint64_t)(sc->_unused[3]) << 32);
580 #else
581     __get_user(set.sig[0], &sc->oldmask);
582     __get_user(set.sig[1], &sc->_unused[3]);
583 #endif
584     target_to_host_sigset_internal(&blocked, &set);
585     set_sigmask(&blocked);
586 
587     __get_user(sr_addr, &sc->regs);
588     if (!lock_user_struct(VERIFY_READ, sr, sr_addr, 1))
589         goto sigsegv;
590     restore_user_regs(env, sr, 1);
591 
592     unlock_user_struct(sr, sr_addr, 1);
593     unlock_user_struct(sc, sc_addr, 1);
594     return -QEMU_ESIGRETURN;
595 
596 sigsegv:
597     unlock_user_struct(sr, sr_addr, 1);
598     unlock_user_struct(sc, sc_addr, 1);
599     force_sig(TARGET_SIGSEGV);
600     return -QEMU_ESIGRETURN;
601 }
602 #endif /* !defined(TARGET_PPC64) */
603 
604 /* See arch/powerpc/kernel/signal_32.c.  */
605 static int do_setcontext(struct target_ucontext *ucp, CPUPPCState *env, int sig)
606 {
607     struct target_mcontext *mcp;
608     target_ulong mcp_addr;
609     sigset_t blocked;
610     target_sigset_t set;
611 
612     if (copy_from_user(&set, h2g(ucp) + offsetof(struct target_ucontext, tuc_sigmask),
613                        sizeof (set)))
614         return 1;
615 
616 #if defined(TARGET_PPC64)
617     mcp_addr = h2g(ucp) +
618         offsetof(struct target_ucontext, tuc_sigcontext.mcontext);
619 #else
620     __get_user(mcp_addr, &ucp->tuc_regs);
621 #endif
622 
623     if (!lock_user_struct(VERIFY_READ, mcp, mcp_addr, 1))
624         return 1;
625 
626     target_to_host_sigset_internal(&blocked, &set);
627     set_sigmask(&blocked);
628     restore_user_regs(env, mcp, sig);
629 
630     unlock_user_struct(mcp, mcp_addr, 1);
631     return 0;
632 }
633 
634 long do_rt_sigreturn(CPUPPCState *env)
635 {
636     struct target_rt_sigframe *rt_sf = NULL;
637     target_ulong rt_sf_addr;
638 
639     rt_sf_addr = env->gpr[1] + SIGNAL_FRAMESIZE + 16;
640     if (!lock_user_struct(VERIFY_READ, rt_sf, rt_sf_addr, 1))
641         goto sigsegv;
642 
643     if (do_setcontext(&rt_sf->uc, env, 1))
644         goto sigsegv;
645 
646     target_restore_altstack(&rt_sf->uc.tuc_stack, env);
647 
648     unlock_user_struct(rt_sf, rt_sf_addr, 1);
649     return -QEMU_ESIGRETURN;
650 
651 sigsegv:
652     unlock_user_struct(rt_sf, rt_sf_addr, 1);
653     force_sig(TARGET_SIGSEGV);
654     return -QEMU_ESIGRETURN;
655 }
656 
657 /* This syscall implements {get,set,swap}context for userland.  */
658 abi_long do_swapcontext(CPUArchState *env, abi_ulong uold_ctx,
659                         abi_ulong unew_ctx, abi_long ctx_size)
660 {
661     struct target_ucontext *uctx;
662     struct target_mcontext *mctx;
663 
664     /* For ppc32, ctx_size is "reserved for future use".
665      * For ppc64, we do not yet support the VSX extension.
666      */
667     if (ctx_size < sizeof(struct target_ucontext)) {
668         return -TARGET_EINVAL;
669     }
670 
671     if (uold_ctx) {
672         TaskState *ts = (TaskState *)thread_cpu->opaque;
673 
674         if (!lock_user_struct(VERIFY_WRITE, uctx, uold_ctx, 1)) {
675             return -TARGET_EFAULT;
676         }
677 
678 #ifdef TARGET_PPC64
679         mctx = &uctx->tuc_sigcontext.mcontext;
680 #else
681         /* ??? The kernel aligns the pointer down here into padding, but
682          * in setup_rt_frame we don't.  Be self-compatible for now.
683          */
684         mctx = &uctx->tuc_mcontext;
685         __put_user(h2g(mctx), &uctx->tuc_regs);
686 #endif
687 
688         save_user_regs(env, mctx);
689         host_to_target_sigset(&uctx->tuc_sigmask, &ts->signal_mask);
690 
691         unlock_user_struct(uctx, uold_ctx, 1);
692     }
693 
694     if (unew_ctx) {
695         int err;
696 
697         if (!lock_user_struct(VERIFY_READ, uctx, unew_ctx, 1)) {
698             return -TARGET_EFAULT;
699         }
700         err = do_setcontext(uctx, env, 0);
701         unlock_user_struct(uctx, unew_ctx, 1);
702 
703         if (err) {
704             /* We cannot return to a partially updated context.  */
705             force_sig(TARGET_SIGSEGV);
706         }
707         return -QEMU_ESIGRETURN;
708     }
709 
710     return 0;
711 }
712 
713 void setup_sigtramp(abi_ulong sigtramp_page)
714 {
715     uint32_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 2 * 8, 0);
716     assert(tramp != NULL);
717 
718 #ifdef TARGET_ARCH_HAS_SETUP_FRAME
719     default_sigreturn = sigtramp_page;
720     encode_trampoline(TARGET_NR_sigreturn, tramp + 0);
721 #endif
722 
723     default_rt_sigreturn = sigtramp_page + 8;
724     encode_trampoline(TARGET_NR_rt_sigreturn, tramp + 2);
725 
726     unlock_user(tramp, sigtramp_page, 2 * 8);
727 }
728