xref: /openbmc/qemu/linux-user/ppc/signal.c (revision b6235a75)
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     ccr = ppc_get_cr(env);
247     __put_user(ccr, &frame->mc_gregs[TARGET_PT_CCR]);
248 
249     /* Save Altivec registers if necessary.  */
250     if (env->insns_flags & PPC_ALTIVEC) {
251         uint32_t *vrsave;
252         for (i = 0; i < 32; i++) {
253             ppc_avr_t *avr = cpu_avr_ptr(env, i);
254             ppc_avr_t *vreg = (ppc_avr_t *)&frame->mc_vregs.altivec[i];
255 
256             __put_user(avr->u64[PPC_VEC_HI], &vreg->u64[0]);
257             __put_user(avr->u64[PPC_VEC_LO], &vreg->u64[1]);
258         }
259 #if defined(TARGET_PPC64)
260         vrsave = (uint32_t *)&frame->mc_vregs.altivec[33];
261         /* 64-bit needs to put a pointer to the vectors in the frame */
262         __put_user(h2g(frame->mc_vregs.altivec), &frame->v_regs);
263 #else
264         vrsave = (uint32_t *)&frame->mc_vregs.altivec[32];
265 #endif
266         __put_user((uint32_t)env->spr[SPR_VRSAVE], vrsave);
267     }
268 
269 #if defined(TARGET_PPC64)
270     /* Save VSX second halves */
271     if (env->insns_flags2 & PPC2_VSX) {
272         uint64_t *vsregs = (uint64_t *)&frame->mc_vregs.altivec[34];
273         for (i = 0; i < 32; i++) {
274             uint64_t *vsrl = cpu_vsrl_ptr(env, i);
275             __put_user(*vsrl, &vsregs[i]);
276         }
277     }
278 #endif
279 
280     /* Save floating point registers.  */
281     if (env->insns_flags & PPC_FLOAT) {
282         for (i = 0; i < 32; i++) {
283             uint64_t *fpr = cpu_fpr_ptr(env, i);
284             __put_user(*fpr, &frame->mc_fregs[i]);
285         }
286         __put_user((uint64_t) env->fpscr, &frame->mc_fregs[32]);
287     }
288 
289 #if !defined(TARGET_PPC64)
290     /* Save SPE registers.  The kernel only saves the high half.  */
291     if (env->insns_flags & PPC_SPE) {
292         for (i = 0; i < ARRAY_SIZE(env->gprh); i++) {
293             __put_user(env->gprh[i], &frame->mc_vregs.spe[i]);
294         }
295         __put_user(env->spe_fscr, &frame->mc_vregs.spe[32]);
296     }
297 #endif
298 
299     /* Store MSR.  */
300     __put_user(msr, &frame->mc_gregs[TARGET_PT_MSR]);
301 }
302 
303 static void encode_trampoline(int sigret, uint32_t *tramp)
304 {
305     /* Set up the sigreturn trampoline: li r0,sigret; sc.  */
306     __put_user(0x38000000 | sigret, &tramp[0]);
307     __put_user(0x44000002, &tramp[1]);
308 }
309 
310 static void restore_user_regs(CPUPPCState *env,
311                               struct target_mcontext *frame, int sig)
312 {
313     target_ulong save_r2 = 0;
314     target_ulong msr;
315     target_ulong xer;
316     target_ulong ccr;
317 
318     int i;
319 
320     if (!sig) {
321         save_r2 = env->gpr[2];
322     }
323 
324     /* Restore general registers.  */
325     for (i = 0; i < ARRAY_SIZE(env->gpr); i++) {
326         __get_user(env->gpr[i], &frame->mc_gregs[i]);
327     }
328     __get_user(env->nip, &frame->mc_gregs[TARGET_PT_NIP]);
329     __get_user(env->ctr, &frame->mc_gregs[TARGET_PT_CTR]);
330     __get_user(env->lr, &frame->mc_gregs[TARGET_PT_LNK]);
331 
332     __get_user(xer, &frame->mc_gregs[TARGET_PT_XER]);
333     cpu_write_xer(env, xer);
334 
335     __get_user(ccr, &frame->mc_gregs[TARGET_PT_CCR]);
336     ppc_set_cr(env, ccr);
337     if (!sig) {
338         env->gpr[2] = save_r2;
339     }
340     /* Restore MSR.  */
341     __get_user(msr, &frame->mc_gregs[TARGET_PT_MSR]);
342 
343     /* If doing signal return, restore the previous little-endian mode.  */
344     if (sig) {
345         ppc_store_msr(env, ((env->msr & ~(1ull << MSR_LE)) |
346                             (msr & (1ull << MSR_LE))));
347     }
348 
349     /* Restore Altivec registers if necessary.  */
350     if (env->insns_flags & PPC_ALTIVEC) {
351         ppc_avr_t *v_regs;
352         uint32_t *vrsave;
353 #if defined(TARGET_PPC64)
354         uint64_t v_addr;
355         /* 64-bit needs to recover the pointer to the vectors from the frame */
356         __get_user(v_addr, &frame->v_regs);
357         v_regs = g2h(env_cpu(env), v_addr);
358 #else
359         v_regs = (ppc_avr_t *)frame->mc_vregs.altivec;
360 #endif
361         for (i = 0; i < 32; i++) {
362             ppc_avr_t *avr = cpu_avr_ptr(env, i);
363             ppc_avr_t *vreg = &v_regs[i];
364 
365             __get_user(avr->u64[PPC_VEC_HI], &vreg->u64[0]);
366             __get_user(avr->u64[PPC_VEC_LO], &vreg->u64[1]);
367         }
368 #if defined(TARGET_PPC64)
369         vrsave = (uint32_t *)&v_regs[33];
370 #else
371         vrsave = (uint32_t *)&v_regs[32];
372 #endif
373         __get_user(env->spr[SPR_VRSAVE], vrsave);
374     }
375 
376 #if defined(TARGET_PPC64)
377     /* Restore VSX second halves */
378     if (env->insns_flags2 & PPC2_VSX) {
379         uint64_t *vsregs = (uint64_t *)&frame->mc_vregs.altivec[34];
380         for (i = 0; i < 32; i++) {
381             uint64_t *vsrl = cpu_vsrl_ptr(env, i);
382             __get_user(*vsrl, &vsregs[i]);
383         }
384     }
385 #endif
386 
387     /* Restore floating point registers.  */
388     if (env->insns_flags & PPC_FLOAT) {
389         uint64_t fpscr;
390         for (i = 0; i < 32; i++) {
391             uint64_t *fpr = cpu_fpr_ptr(env, i);
392             __get_user(*fpr, &frame->mc_fregs[i]);
393         }
394         __get_user(fpscr, &frame->mc_fregs[32]);
395         env->fpscr = (uint32_t) fpscr;
396     }
397 
398 #if !defined(TARGET_PPC64)
399     /* Save SPE registers.  The kernel only saves the high half.  */
400     if (env->insns_flags & PPC_SPE) {
401         for (i = 0; i < ARRAY_SIZE(env->gprh); i++) {
402             __get_user(env->gprh[i], &frame->mc_vregs.spe[i]);
403         }
404         __get_user(env->spe_fscr, &frame->mc_vregs.spe[32]);
405     }
406 #endif
407 }
408 
409 #if !defined(TARGET_PPC64)
410 void setup_frame(int sig, struct target_sigaction *ka,
411                  target_sigset_t *set, CPUPPCState *env)
412 {
413     struct target_sigframe *frame;
414     struct target_sigcontext *sc;
415     target_ulong frame_addr, newsp;
416     int err = 0;
417 
418     frame_addr = get_sigframe(ka, env, sizeof(*frame));
419     trace_user_setup_frame(env, frame_addr);
420     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 1))
421         goto sigsegv;
422     sc = &frame->sctx;
423 
424     __put_user(ka->_sa_handler, &sc->handler);
425     __put_user(set->sig[0], &sc->oldmask);
426     __put_user(set->sig[1], &sc->_unused[3]);
427     __put_user(h2g(&frame->mctx), &sc->regs);
428     __put_user(sig, &sc->signal);
429 
430     /* Save user regs.  */
431     save_user_regs(env, &frame->mctx);
432 
433     env->lr = default_sigreturn;
434 
435     /* Turn off all fp exceptions.  */
436     env->fpscr = 0;
437 
438     /* Create a stack frame for the caller of the handler.  */
439     newsp = frame_addr - SIGNAL_FRAMESIZE;
440     err |= put_user(env->gpr[1], newsp, target_ulong);
441 
442     if (err)
443         goto sigsegv;
444 
445     /* Set up registers for signal handler.  */
446     env->gpr[1] = newsp;
447     env->gpr[3] = sig;
448     env->gpr[4] = frame_addr + offsetof(struct target_sigframe, sctx);
449 
450     env->nip = (target_ulong) ka->_sa_handler;
451 
452     /* Signal handlers are entered in big-endian mode.  */
453     ppc_store_msr(env, env->msr & ~(1ull << MSR_LE));
454 
455     unlock_user_struct(frame, frame_addr, 1);
456     return;
457 
458 sigsegv:
459     unlock_user_struct(frame, frame_addr, 1);
460     force_sigsegv(sig);
461 }
462 #endif /* !defined(TARGET_PPC64) */
463 
464 void setup_rt_frame(int sig, struct target_sigaction *ka,
465                     target_siginfo_t *info,
466                     target_sigset_t *set, CPUPPCState *env)
467 {
468     struct target_rt_sigframe *rt_sf;
469     struct target_mcontext *mctx = 0;
470     target_ulong rt_sf_addr, newsp = 0;
471     int i, err = 0;
472 #if defined(TARGET_PPC64)
473     struct target_sigcontext *sc = 0;
474     struct image_info *image = ((TaskState *)thread_cpu->opaque)->info;
475 #endif
476 
477     rt_sf_addr = get_sigframe(ka, env, sizeof(*rt_sf));
478     if (!lock_user_struct(VERIFY_WRITE, rt_sf, rt_sf_addr, 1))
479         goto sigsegv;
480 
481     tswap_siginfo(&rt_sf->info, info);
482 
483     __put_user(0, &rt_sf->uc.tuc_flags);
484     __put_user(0, &rt_sf->uc.tuc_link);
485     target_save_altstack(&rt_sf->uc.tuc_stack, env);
486 #if !defined(TARGET_PPC64)
487     __put_user(h2g (&rt_sf->uc.tuc_mcontext),
488                &rt_sf->uc.tuc_regs);
489 #endif
490     for(i = 0; i < TARGET_NSIG_WORDS; i++) {
491         __put_user(set->sig[i], &rt_sf->uc.tuc_sigmask.sig[i]);
492     }
493 
494 #if defined(TARGET_PPC64)
495     mctx = &rt_sf->uc.tuc_sigcontext.mcontext;
496 
497     sc = &rt_sf->uc.tuc_sigcontext;
498     __put_user(h2g(mctx), &sc->regs);
499     __put_user(sig, &sc->signal);
500 #else
501     mctx = &rt_sf->uc.tuc_mcontext;
502 #endif
503 
504     save_user_regs(env, mctx);
505 
506     env->lr = default_rt_sigreturn;
507 
508     /* Turn off all fp exceptions.  */
509     env->fpscr = 0;
510 
511     /* Create a stack frame for the caller of the handler.  */
512     newsp = rt_sf_addr - (SIGNAL_FRAMESIZE + 16);
513     err |= put_user(env->gpr[1], newsp, target_ulong);
514 
515     if (err)
516         goto sigsegv;
517 
518     /* Set up registers for signal handler.  */
519     env->gpr[1] = newsp;
520     env->gpr[3] = (target_ulong) sig;
521     env->gpr[4] = (target_ulong) h2g(&rt_sf->info);
522     env->gpr[5] = (target_ulong) h2g(&rt_sf->uc);
523     env->gpr[6] = (target_ulong) h2g(rt_sf);
524 
525 #if defined(TARGET_PPC64)
526     if (get_ppc64_abi(image) < 2) {
527         /* ELFv1 PPC64 function pointers are pointers to OPD entries. */
528         struct target_func_ptr *handler =
529             (struct target_func_ptr *)g2h(env_cpu(env), ka->_sa_handler);
530         env->nip = tswapl(handler->entry);
531         env->gpr[2] = tswapl(handler->toc);
532     } else {
533         /* ELFv2 PPC64 function pointers are entry points. R12 must also be set. */
534         env->gpr[12] = env->nip = ka->_sa_handler;
535     }
536 #else
537     env->nip = (target_ulong) ka->_sa_handler;
538 #endif
539 
540 #if TARGET_BIG_ENDIAN
541     /* Signal handlers are entered in big-endian mode.  */
542     ppc_store_msr(env, env->msr & ~(1ull << MSR_LE));
543 #else
544     /* Signal handlers are entered in little-endian mode.  */
545     ppc_store_msr(env, env->msr | (1ull << MSR_LE));
546 #endif
547 
548     unlock_user_struct(rt_sf, rt_sf_addr, 1);
549     return;
550 
551 sigsegv:
552     unlock_user_struct(rt_sf, rt_sf_addr, 1);
553     force_sigsegv(sig);
554 
555 }
556 
557 #if !defined(TARGET_PPC64)
558 long do_sigreturn(CPUPPCState *env)
559 {
560     struct target_sigcontext *sc = NULL;
561     struct target_mcontext *sr = NULL;
562     target_ulong sr_addr = 0, sc_addr;
563     sigset_t blocked;
564     target_sigset_t set;
565 
566     sc_addr = env->gpr[1] + SIGNAL_FRAMESIZE;
567     if (!lock_user_struct(VERIFY_READ, sc, sc_addr, 1))
568         goto sigsegv;
569 
570     __get_user(set.sig[0], &sc->oldmask);
571     __get_user(set.sig[1], &sc->_unused[3]);
572 
573     target_to_host_sigset_internal(&blocked, &set);
574     set_sigmask(&blocked);
575 
576     __get_user(sr_addr, &sc->regs);
577     if (!lock_user_struct(VERIFY_READ, sr, sr_addr, 1))
578         goto sigsegv;
579     restore_user_regs(env, sr, 1);
580 
581     unlock_user_struct(sr, sr_addr, 1);
582     unlock_user_struct(sc, sc_addr, 1);
583     return -QEMU_ESIGRETURN;
584 
585 sigsegv:
586     unlock_user_struct(sr, sr_addr, 1);
587     unlock_user_struct(sc, sc_addr, 1);
588     force_sig(TARGET_SIGSEGV);
589     return -QEMU_ESIGRETURN;
590 }
591 #endif /* !defined(TARGET_PPC64) */
592 
593 /* See arch/powerpc/kernel/signal_32.c.  */
594 static int do_setcontext(struct target_ucontext *ucp, CPUPPCState *env, int sig)
595 {
596     struct target_mcontext *mcp;
597     target_ulong mcp_addr;
598     sigset_t blocked;
599     target_sigset_t set;
600 
601     if (copy_from_user(&set, h2g(ucp) + offsetof(struct target_ucontext, tuc_sigmask),
602                        sizeof (set)))
603         return 1;
604 
605 #if defined(TARGET_PPC64)
606     mcp_addr = h2g(ucp) +
607         offsetof(struct target_ucontext, tuc_sigcontext.mcontext);
608 #else
609     __get_user(mcp_addr, &ucp->tuc_regs);
610 #endif
611 
612     if (!lock_user_struct(VERIFY_READ, mcp, mcp_addr, 1))
613         return 1;
614 
615     target_to_host_sigset_internal(&blocked, &set);
616     set_sigmask(&blocked);
617     restore_user_regs(env, mcp, sig);
618 
619     unlock_user_struct(mcp, mcp_addr, 1);
620     return 0;
621 }
622 
623 long do_rt_sigreturn(CPUPPCState *env)
624 {
625     struct target_rt_sigframe *rt_sf = NULL;
626     target_ulong rt_sf_addr;
627 
628     rt_sf_addr = env->gpr[1] + SIGNAL_FRAMESIZE + 16;
629     if (!lock_user_struct(VERIFY_READ, rt_sf, rt_sf_addr, 1))
630         goto sigsegv;
631 
632     if (do_setcontext(&rt_sf->uc, env, 1))
633         goto sigsegv;
634 
635     target_restore_altstack(&rt_sf->uc.tuc_stack, env);
636 
637     unlock_user_struct(rt_sf, rt_sf_addr, 1);
638     return -QEMU_ESIGRETURN;
639 
640 sigsegv:
641     unlock_user_struct(rt_sf, rt_sf_addr, 1);
642     force_sig(TARGET_SIGSEGV);
643     return -QEMU_ESIGRETURN;
644 }
645 
646 /* This syscall implements {get,set,swap}context for userland.  */
647 abi_long do_swapcontext(CPUArchState *env, abi_ulong uold_ctx,
648                         abi_ulong unew_ctx, abi_long ctx_size)
649 {
650     struct target_ucontext *uctx;
651     struct target_mcontext *mctx;
652 
653     /* For ppc32, ctx_size is "reserved for future use".
654      * For ppc64, we do not yet support the VSX extension.
655      */
656     if (ctx_size < sizeof(struct target_ucontext)) {
657         return -TARGET_EINVAL;
658     }
659 
660     if (uold_ctx) {
661         TaskState *ts = (TaskState *)thread_cpu->opaque;
662 
663         if (!lock_user_struct(VERIFY_WRITE, uctx, uold_ctx, 1)) {
664             return -TARGET_EFAULT;
665         }
666 
667 #ifdef TARGET_PPC64
668         mctx = &uctx->tuc_sigcontext.mcontext;
669 #else
670         /* ??? The kernel aligns the pointer down here into padding, but
671          * in setup_rt_frame we don't.  Be self-compatible for now.
672          */
673         mctx = &uctx->tuc_mcontext;
674         __put_user(h2g(mctx), &uctx->tuc_regs);
675 #endif
676 
677         save_user_regs(env, mctx);
678         host_to_target_sigset(&uctx->tuc_sigmask, &ts->signal_mask);
679 
680         unlock_user_struct(uctx, uold_ctx, 1);
681     }
682 
683     if (unew_ctx) {
684         int err;
685 
686         if (!lock_user_struct(VERIFY_READ, uctx, unew_ctx, 1)) {
687             return -TARGET_EFAULT;
688         }
689         err = do_setcontext(uctx, env, 0);
690         unlock_user_struct(uctx, unew_ctx, 1);
691 
692         if (err) {
693             /* We cannot return to a partially updated context.  */
694             force_sig(TARGET_SIGSEGV);
695         }
696         return -QEMU_ESIGRETURN;
697     }
698 
699     return 0;
700 }
701 
702 void setup_sigtramp(abi_ulong sigtramp_page)
703 {
704     uint32_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 2 * 8, 0);
705     assert(tramp != NULL);
706 
707 #ifdef TARGET_ARCH_HAS_SETUP_FRAME
708     default_sigreturn = sigtramp_page;
709     encode_trampoline(TARGET_NR_sigreturn, tramp + 0);
710 #endif
711 
712     default_rt_sigreturn = sigtramp_page + 8;
713     encode_trampoline(TARGET_NR_rt_sigreturn, tramp + 2);
714 
715     unlock_user(tramp, sigtramp_page, 2 * 8);
716 }
717