xref: /openbmc/qemu/linux-user/ppc/signal.c (revision 259ebed4)
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 #include "vdso-asmoffset.h"
25 
26 /* See arch/powerpc/include/asm/ucontext.h.  Only used for 32-bit PPC;
27    on 64-bit PPC, sigcontext and mcontext are one and the same.  */
28 struct target_mcontext {
29     target_ulong mc_gregs[48];
30     /* Includes fpscr.  */
31     uint64_t mc_fregs[33];
32 
33 #if defined(TARGET_PPC64)
34     /* Pointer to the vector regs */
35     target_ulong v_regs;
36     /*
37      * On ppc64, this mcontext structure is naturally *unaligned*,
38      * or rather it is aligned on a 8 bytes boundary but not on
39      * a 16 byte boundary.  This pad fixes it up.  This is why we
40      * cannot use ppc_avr_t, which would force alignment.  This is
41      * also why the vector regs are referenced in the ABI by the
42      * v_regs pointer above so any amount of padding can be added here.
43      */
44     target_ulong pad;
45     /* VSCR and VRSAVE are saved separately.  Also reserve space for VSX. */
46     struct {
47         uint64_t altivec[34 + 16][2];
48     } mc_vregs;
49 #else
50     target_ulong mc_pad[2];
51 
52     /* We need to handle Altivec and SPE at the same time, which no
53        kernel needs to do.  Fortunately, the kernel defines this bit to
54        be Altivec-register-large all the time, rather than trying to
55        twiddle it based on the specific platform.  */
56     union {
57         /* SPE vector registers.  One extra for SPEFSCR.  */
58         uint32_t spe[33];
59         /*
60          * Altivec vector registers.  One extra for VRSAVE.
61          * On ppc32, we are already aligned to 16 bytes.  We could
62          * use ppc_avr_t, but choose to share the same type as ppc64.
63          */
64         uint64_t altivec[33][2];
65     } mc_vregs;
66 #endif
67 };
68 
69 QEMU_BUILD_BUG_ON(offsetof(struct target_mcontext, mc_fregs)
70                   != offsetof_mcontext_fregs);
71 #if defined(TARGET_PPC64)
72 QEMU_BUILD_BUG_ON(offsetof(struct target_mcontext, v_regs)
73                   != offsetof_mcontext_vregs_ptr);
74 #else
75 QEMU_BUILD_BUG_ON(offsetof(struct target_mcontext, mc_vregs)
76                   != offsetof_mcontext_vregs);
77 #endif
78 
79 /* See arch/powerpc/include/asm/sigcontext.h.  */
80 struct target_sigcontext {
81     target_ulong _unused[4];
82     int32_t signal;
83 #if defined(TARGET_PPC64)
84     int32_t pad0;
85 #endif
86     target_ulong handler;
87     target_ulong oldmask;
88     target_ulong regs;      /* struct pt_regs __user * */
89 #if defined(TARGET_PPC64)
90     struct target_mcontext mcontext;
91 #endif
92 };
93 
94 /* Indices for target_mcontext.mc_gregs, below.
95    See arch/powerpc/include/asm/ptrace.h for details.  */
96 enum {
97     TARGET_PT_R0 = 0,
98     TARGET_PT_R1 = 1,
99     TARGET_PT_R2 = 2,
100     TARGET_PT_R3 = 3,
101     TARGET_PT_R4 = 4,
102     TARGET_PT_R5 = 5,
103     TARGET_PT_R6 = 6,
104     TARGET_PT_R7 = 7,
105     TARGET_PT_R8 = 8,
106     TARGET_PT_R9 = 9,
107     TARGET_PT_R10 = 10,
108     TARGET_PT_R11 = 11,
109     TARGET_PT_R12 = 12,
110     TARGET_PT_R13 = 13,
111     TARGET_PT_R14 = 14,
112     TARGET_PT_R15 = 15,
113     TARGET_PT_R16 = 16,
114     TARGET_PT_R17 = 17,
115     TARGET_PT_R18 = 18,
116     TARGET_PT_R19 = 19,
117     TARGET_PT_R20 = 20,
118     TARGET_PT_R21 = 21,
119     TARGET_PT_R22 = 22,
120     TARGET_PT_R23 = 23,
121     TARGET_PT_R24 = 24,
122     TARGET_PT_R25 = 25,
123     TARGET_PT_R26 = 26,
124     TARGET_PT_R27 = 27,
125     TARGET_PT_R28 = 28,
126     TARGET_PT_R29 = 29,
127     TARGET_PT_R30 = 30,
128     TARGET_PT_R31 = 31,
129     TARGET_PT_NIP = 32,
130     TARGET_PT_MSR = 33,
131     TARGET_PT_ORIG_R3 = 34,
132     TARGET_PT_CTR = 35,
133     TARGET_PT_LNK = 36,
134     TARGET_PT_XER = 37,
135     TARGET_PT_CCR = 38,
136     /* Yes, there are two registers with #39.  One is 64-bit only.  */
137     TARGET_PT_MQ = 39,
138     TARGET_PT_SOFTE = 39,
139     TARGET_PT_TRAP = 40,
140     TARGET_PT_DAR = 41,
141     TARGET_PT_DSISR = 42,
142     TARGET_PT_RESULT = 43,
143     TARGET_PT_REGS_COUNT = 44
144 };
145 
146 
147 struct target_ucontext {
148     target_ulong tuc_flags;
149     target_ulong tuc_link;    /* ucontext_t __user * */
150     struct target_sigaltstack tuc_stack;
151 #if !defined(TARGET_PPC64)
152     int32_t tuc_pad[7];
153     target_ulong tuc_regs;    /* struct mcontext __user *
154                                 points to uc_mcontext field */
155 #endif
156     target_sigset_t tuc_sigmask;
157 #if defined(TARGET_PPC64)
158     target_sigset_t unused[15]; /* Allow for uc_sigmask growth */
159     struct target_sigcontext tuc_sigcontext;
160 #else
161     int32_t tuc_maskext[30];
162     int32_t tuc_pad2[3];
163     struct target_mcontext tuc_mcontext;
164 #endif
165 };
166 
167 #if !defined(TARGET_PPC64)
168 /* See arch/powerpc/kernel/signal_32.c.  */
169 struct target_sigframe {
170     struct target_sigcontext sctx;
171     struct target_mcontext mctx;
172     int32_t abigap[56];
173 };
174 
175 QEMU_BUILD_BUG_ON(offsetof(struct target_sigframe, mctx)
176                   != offsetof_sigframe_mcontext);
177 #endif
178 
179 #if defined(TARGET_PPC64)
180 
181 #define TARGET_TRAMP_SIZE 6
182 
183 struct target_rt_sigframe {
184     /* sys_rt_sigreturn requires the ucontext be the first field */
185     struct target_ucontext uc;
186     target_ulong  _unused[2];
187     uint32_t trampoline[TARGET_TRAMP_SIZE];
188     target_ulong pinfo; /* struct siginfo __user * */
189     target_ulong puc; /* void __user * */
190     struct target_siginfo info;
191     /* 64 bit ABI allows for 288 bytes below sp before decrementing it. */
192     char abigap[288];
193 } __attribute__((aligned(16)));
194 
195 QEMU_BUILD_BUG_ON(offsetof(struct target_rt_sigframe,
196                            uc.tuc_sigcontext.mcontext)
197                   != offsetof_rt_sigframe_mcontext);
198 
199 #else
200 
201 struct target_rt_sigframe {
202     struct target_siginfo info;
203     struct target_ucontext uc;
204     int32_t abigap[56];
205 };
206 
207 QEMU_BUILD_BUG_ON(offsetof(struct target_rt_sigframe, uc.tuc_mcontext)
208                   != offsetof_rt_sigframe_mcontext);
209 
210 #endif
211 
212 #if defined(TARGET_PPC64)
213 
214 struct target_func_ptr {
215     target_ulong entry;
216     target_ulong toc;
217 };
218 
219 #endif
220 
221 /* See arch/powerpc/kernel/signal.c.  */
222 static target_ulong get_sigframe(struct target_sigaction *ka,
223                                  CPUPPCState *env,
224                                  int frame_size)
225 {
226     target_ulong oldsp;
227 
228     oldsp = target_sigsp(get_sp_from_cpustate(env), ka);
229 
230     return (oldsp - frame_size) & ~0xFUL;
231 }
232 
233 #if TARGET_BIG_ENDIAN == HOST_BIG_ENDIAN
234 #define PPC_VEC_HI      0
235 #define PPC_VEC_LO      1
236 #else
237 #define PPC_VEC_HI      1
238 #define PPC_VEC_LO      0
239 #endif
240 
241 
242 static void save_user_regs(CPUPPCState *env, struct target_mcontext *frame)
243 {
244     target_ulong msr = env->msr;
245     int i;
246     uint32_t ccr = 0;
247 
248     /* In general, the kernel attempts to be intelligent about what it
249        needs to save for Altivec/FP/SPE registers.  We don't care that
250        much, so we just go ahead and save everything.  */
251 
252     /* Save general registers.  */
253     for (i = 0; i < ARRAY_SIZE(env->gpr); i++) {
254         __put_user(env->gpr[i], &frame->mc_gregs[i]);
255     }
256     __put_user(env->nip, &frame->mc_gregs[TARGET_PT_NIP]);
257     __put_user(env->ctr, &frame->mc_gregs[TARGET_PT_CTR]);
258     __put_user(env->lr, &frame->mc_gregs[TARGET_PT_LNK]);
259     __put_user(cpu_read_xer(env), &frame->mc_gregs[TARGET_PT_XER]);
260 
261     ccr = ppc_get_cr(env);
262     __put_user(ccr, &frame->mc_gregs[TARGET_PT_CCR]);
263 
264     /* Save Altivec registers if necessary.  */
265     if (env->insns_flags & PPC_ALTIVEC) {
266         uint32_t *vrsave;
267         for (i = 0; i < 32; i++) {
268             ppc_avr_t *avr = cpu_avr_ptr(env, i);
269             ppc_avr_t *vreg = (ppc_avr_t *)&frame->mc_vregs.altivec[i];
270 
271             __put_user(avr->u64[PPC_VEC_HI], &vreg->u64[0]);
272             __put_user(avr->u64[PPC_VEC_LO], &vreg->u64[1]);
273         }
274 #if defined(TARGET_PPC64)
275         vrsave = (uint32_t *)&frame->mc_vregs.altivec[33];
276         /* 64-bit needs to put a pointer to the vectors in the frame */
277         __put_user(h2g(frame->mc_vregs.altivec), &frame->v_regs);
278 #else
279         vrsave = (uint32_t *)&frame->mc_vregs.altivec[32];
280 #endif
281         __put_user((uint32_t)env->spr[SPR_VRSAVE], vrsave);
282     }
283 
284 #if defined(TARGET_PPC64)
285     /* Save VSX second halves */
286     if (env->insns_flags2 & PPC2_VSX) {
287         uint64_t *vsregs = (uint64_t *)&frame->mc_vregs.altivec[34];
288         for (i = 0; i < 32; i++) {
289             uint64_t *vsrl = cpu_vsrl_ptr(env, i);
290             __put_user(*vsrl, &vsregs[i]);
291         }
292     }
293 #endif
294 
295     /* Save floating point registers.  */
296     if (env->insns_flags & PPC_FLOAT) {
297         for (i = 0; i < 32; i++) {
298             uint64_t *fpr = cpu_fpr_ptr(env, i);
299             __put_user(*fpr, &frame->mc_fregs[i]);
300         }
301         __put_user((uint64_t) env->fpscr, &frame->mc_fregs[32]);
302     }
303 
304 #if !defined(TARGET_PPC64)
305     /* Save SPE registers.  The kernel only saves the high half.  */
306     if (env->insns_flags & PPC_SPE) {
307         for (i = 0; i < ARRAY_SIZE(env->gprh); i++) {
308             __put_user(env->gprh[i], &frame->mc_vregs.spe[i]);
309         }
310         __put_user(env->spe_fscr, &frame->mc_vregs.spe[32]);
311     }
312 #endif
313 
314     /* Store MSR.  */
315     __put_user(msr, &frame->mc_gregs[TARGET_PT_MSR]);
316 }
317 
318 static void encode_trampoline(int sigret, uint32_t *tramp)
319 {
320     /* Set up the sigreturn trampoline: li r0,sigret; sc.  */
321     __put_user(0x38000000 | sigret, &tramp[0]);
322     __put_user(0x44000002, &tramp[1]);
323 }
324 
325 static void restore_user_regs(CPUPPCState *env,
326                               struct target_mcontext *frame, int sig)
327 {
328     target_ulong save_r2 = 0;
329     target_ulong msr;
330     target_ulong xer;
331     target_ulong ccr;
332 
333     int i;
334 
335     if (!sig) {
336         save_r2 = env->gpr[2];
337     }
338 
339     /* Restore general registers.  */
340     for (i = 0; i < ARRAY_SIZE(env->gpr); i++) {
341         __get_user(env->gpr[i], &frame->mc_gregs[i]);
342     }
343     __get_user(env->nip, &frame->mc_gregs[TARGET_PT_NIP]);
344     __get_user(env->ctr, &frame->mc_gregs[TARGET_PT_CTR]);
345     __get_user(env->lr, &frame->mc_gregs[TARGET_PT_LNK]);
346 
347     __get_user(xer, &frame->mc_gregs[TARGET_PT_XER]);
348     cpu_write_xer(env, xer);
349 
350     __get_user(ccr, &frame->mc_gregs[TARGET_PT_CCR]);
351     ppc_set_cr(env, ccr);
352     if (!sig) {
353         env->gpr[2] = save_r2;
354     }
355     /* Restore MSR.  */
356     __get_user(msr, &frame->mc_gregs[TARGET_PT_MSR]);
357 
358     /* If doing signal return, restore the previous little-endian mode.  */
359     if (sig) {
360         ppc_store_msr(env, ((env->msr & ~(1ull << MSR_LE)) |
361                             (msr & (1ull << MSR_LE))));
362     }
363 
364     /* Restore Altivec registers if necessary.  */
365     if (env->insns_flags & PPC_ALTIVEC) {
366         ppc_avr_t *v_regs;
367         uint32_t *vrsave;
368 #if defined(TARGET_PPC64)
369         uint64_t v_addr;
370         /* 64-bit needs to recover the pointer to the vectors from the frame */
371         __get_user(v_addr, &frame->v_regs);
372         v_regs = g2h(env_cpu(env), v_addr);
373 #else
374         v_regs = (ppc_avr_t *)frame->mc_vregs.altivec;
375 #endif
376         for (i = 0; i < 32; i++) {
377             ppc_avr_t *avr = cpu_avr_ptr(env, i);
378             ppc_avr_t *vreg = &v_regs[i];
379 
380             __get_user(avr->u64[PPC_VEC_HI], &vreg->u64[0]);
381             __get_user(avr->u64[PPC_VEC_LO], &vreg->u64[1]);
382         }
383 #if defined(TARGET_PPC64)
384         vrsave = (uint32_t *)&v_regs[33];
385 #else
386         vrsave = (uint32_t *)&v_regs[32];
387 #endif
388         __get_user(env->spr[SPR_VRSAVE], vrsave);
389     }
390 
391 #if defined(TARGET_PPC64)
392     /* Restore VSX second halves */
393     if (env->insns_flags2 & PPC2_VSX) {
394         uint64_t *vsregs = (uint64_t *)&frame->mc_vregs.altivec[34];
395         for (i = 0; i < 32; i++) {
396             uint64_t *vsrl = cpu_vsrl_ptr(env, i);
397             __get_user(*vsrl, &vsregs[i]);
398         }
399     }
400 #endif
401 
402     /* Restore floating point registers.  */
403     if (env->insns_flags & PPC_FLOAT) {
404         uint64_t fpscr;
405         for (i = 0; i < 32; i++) {
406             uint64_t *fpr = cpu_fpr_ptr(env, i);
407             __get_user(*fpr, &frame->mc_fregs[i]);
408         }
409         __get_user(fpscr, &frame->mc_fregs[32]);
410         env->fpscr = (uint32_t) fpscr;
411     }
412 
413 #if !defined(TARGET_PPC64)
414     /* Save SPE registers.  The kernel only saves the high half.  */
415     if (env->insns_flags & PPC_SPE) {
416         for (i = 0; i < ARRAY_SIZE(env->gprh); i++) {
417             __get_user(env->gprh[i], &frame->mc_vregs.spe[i]);
418         }
419         __get_user(env->spe_fscr, &frame->mc_vregs.spe[32]);
420     }
421 #endif
422 }
423 
424 #if !defined(TARGET_PPC64)
425 void setup_frame(int sig, struct target_sigaction *ka,
426                  target_sigset_t *set, CPUPPCState *env)
427 {
428     struct target_sigframe *frame;
429     struct target_sigcontext *sc;
430     target_ulong frame_addr, newsp;
431     int err = 0;
432 
433     frame_addr = get_sigframe(ka, env, sizeof(*frame));
434     trace_user_setup_frame(env, frame_addr);
435     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 1))
436         goto sigsegv;
437     sc = &frame->sctx;
438 
439     __put_user(ka->_sa_handler, &sc->handler);
440     __put_user(set->sig[0], &sc->oldmask);
441     __put_user(set->sig[1], &sc->_unused[3]);
442     __put_user(h2g(&frame->mctx), &sc->regs);
443     __put_user(sig, &sc->signal);
444 
445     /* Save user regs.  */
446     save_user_regs(env, &frame->mctx);
447 
448     env->lr = default_sigreturn;
449 
450     /* Turn off all fp exceptions.  */
451     env->fpscr = 0;
452 
453     /* Create a stack frame for the caller of the handler.  */
454     newsp = frame_addr - SIGNAL_FRAMESIZE;
455     err |= put_user(env->gpr[1], newsp, target_ulong);
456 
457     if (err)
458         goto sigsegv;
459 
460     /* Set up registers for signal handler.  */
461     env->gpr[1] = newsp;
462     env->gpr[3] = sig;
463     env->gpr[4] = frame_addr + offsetof(struct target_sigframe, sctx);
464 
465     env->nip = (target_ulong) ka->_sa_handler;
466 
467     /* Signal handlers are entered in big-endian mode.  */
468     ppc_store_msr(env, env->msr & ~(1ull << MSR_LE));
469 
470     unlock_user_struct(frame, frame_addr, 1);
471     return;
472 
473 sigsegv:
474     unlock_user_struct(frame, frame_addr, 1);
475     force_sigsegv(sig);
476 }
477 #endif /* !defined(TARGET_PPC64) */
478 
479 void setup_rt_frame(int sig, struct target_sigaction *ka,
480                     target_siginfo_t *info,
481                     target_sigset_t *set, CPUPPCState *env)
482 {
483     struct target_rt_sigframe *rt_sf;
484     struct target_mcontext *mctx = 0;
485     target_ulong rt_sf_addr, newsp = 0;
486     int i, err = 0;
487 #if defined(TARGET_PPC64)
488     struct target_sigcontext *sc = 0;
489     struct image_info *image = ((TaskState *)thread_cpu->opaque)->info;
490 #endif
491 
492     rt_sf_addr = get_sigframe(ka, env, sizeof(*rt_sf));
493     if (!lock_user_struct(VERIFY_WRITE, rt_sf, rt_sf_addr, 1))
494         goto sigsegv;
495 
496     tswap_siginfo(&rt_sf->info, info);
497 
498     __put_user(0, &rt_sf->uc.tuc_flags);
499     __put_user(0, &rt_sf->uc.tuc_link);
500     target_save_altstack(&rt_sf->uc.tuc_stack, env);
501 #if !defined(TARGET_PPC64)
502     __put_user(h2g (&rt_sf->uc.tuc_mcontext),
503                &rt_sf->uc.tuc_regs);
504 #endif
505     for(i = 0; i < TARGET_NSIG_WORDS; i++) {
506         __put_user(set->sig[i], &rt_sf->uc.tuc_sigmask.sig[i]);
507     }
508 
509 #if defined(TARGET_PPC64)
510     mctx = &rt_sf->uc.tuc_sigcontext.mcontext;
511 
512     sc = &rt_sf->uc.tuc_sigcontext;
513     __put_user(h2g(mctx), &sc->regs);
514     __put_user(sig, &sc->signal);
515 #else
516     mctx = &rt_sf->uc.tuc_mcontext;
517 #endif
518 
519     save_user_regs(env, mctx);
520 
521     env->lr = default_rt_sigreturn;
522 
523     /* Turn off all fp exceptions.  */
524     env->fpscr = 0;
525 
526     /* Create a stack frame for the caller of the handler.  */
527     newsp = rt_sf_addr - (SIGNAL_FRAMESIZE + 16);
528     err |= put_user(env->gpr[1], newsp, target_ulong);
529 
530     if (err)
531         goto sigsegv;
532 
533     /* Set up registers for signal handler.  */
534     env->gpr[1] = newsp;
535     env->gpr[3] = (target_ulong) sig;
536     env->gpr[4] = (target_ulong) h2g(&rt_sf->info);
537     env->gpr[5] = (target_ulong) h2g(&rt_sf->uc);
538     env->gpr[6] = (target_ulong) h2g(rt_sf);
539 
540 #if defined(TARGET_PPC64)
541     if (get_ppc64_abi(image) < 2) {
542         /* ELFv1 PPC64 function pointers are pointers to OPD entries. */
543         struct target_func_ptr *handler =
544             (struct target_func_ptr *)g2h(env_cpu(env), ka->_sa_handler);
545         env->nip = tswapl(handler->entry);
546         env->gpr[2] = tswapl(handler->toc);
547     } else {
548         /* ELFv2 PPC64 function pointers are entry points. R12 must also be set. */
549         env->gpr[12] = env->nip = ka->_sa_handler;
550     }
551 #else
552     env->nip = (target_ulong) ka->_sa_handler;
553 #endif
554 
555 #if TARGET_BIG_ENDIAN
556     /* Signal handlers are entered in big-endian mode.  */
557     ppc_store_msr(env, env->msr & ~(1ull << MSR_LE));
558 #else
559     /* Signal handlers are entered in little-endian mode.  */
560     ppc_store_msr(env, env->msr | (1ull << MSR_LE));
561 #endif
562 
563     unlock_user_struct(rt_sf, rt_sf_addr, 1);
564     return;
565 
566 sigsegv:
567     unlock_user_struct(rt_sf, rt_sf_addr, 1);
568     force_sigsegv(sig);
569 
570 }
571 
572 #if !defined(TARGET_PPC64)
573 long do_sigreturn(CPUPPCState *env)
574 {
575     struct target_sigcontext *sc = NULL;
576     struct target_mcontext *sr = NULL;
577     target_ulong sr_addr = 0, sc_addr;
578     sigset_t blocked;
579     target_sigset_t set;
580 
581     sc_addr = env->gpr[1] + SIGNAL_FRAMESIZE;
582     if (!lock_user_struct(VERIFY_READ, sc, sc_addr, 1))
583         goto sigsegv;
584 
585     __get_user(set.sig[0], &sc->oldmask);
586     __get_user(set.sig[1], &sc->_unused[3]);
587 
588     target_to_host_sigset_internal(&blocked, &set);
589     set_sigmask(&blocked);
590 
591     __get_user(sr_addr, &sc->regs);
592     if (!lock_user_struct(VERIFY_READ, sr, sr_addr, 1))
593         goto sigsegv;
594     restore_user_regs(env, sr, 1);
595 
596     unlock_user_struct(sr, sr_addr, 1);
597     unlock_user_struct(sc, sc_addr, 1);
598     return -QEMU_ESIGRETURN;
599 
600 sigsegv:
601     unlock_user_struct(sr, sr_addr, 1);
602     unlock_user_struct(sc, sc_addr, 1);
603     force_sig(TARGET_SIGSEGV);
604     return -QEMU_ESIGRETURN;
605 }
606 #endif /* !defined(TARGET_PPC64) */
607 
608 /* See arch/powerpc/kernel/signal_32.c.  */
609 static int do_setcontext(struct target_ucontext *ucp, CPUPPCState *env, int sig)
610 {
611     struct target_mcontext *mcp;
612     target_ulong mcp_addr;
613     sigset_t blocked;
614     target_sigset_t set;
615 
616     if (copy_from_user(&set, h2g(ucp) + offsetof(struct target_ucontext, tuc_sigmask),
617                        sizeof (set)))
618         return 1;
619 
620 #if defined(TARGET_PPC64)
621     mcp_addr = h2g(ucp) +
622         offsetof(struct target_ucontext, tuc_sigcontext.mcontext);
623 #else
624     __get_user(mcp_addr, &ucp->tuc_regs);
625 #endif
626 
627     if (!lock_user_struct(VERIFY_READ, mcp, mcp_addr, 1))
628         return 1;
629 
630     target_to_host_sigset_internal(&blocked, &set);
631     set_sigmask(&blocked);
632     restore_user_regs(env, mcp, sig);
633 
634     unlock_user_struct(mcp, mcp_addr, 1);
635     return 0;
636 }
637 
638 long do_rt_sigreturn(CPUPPCState *env)
639 {
640     struct target_rt_sigframe *rt_sf = NULL;
641     target_ulong rt_sf_addr;
642 
643     rt_sf_addr = env->gpr[1] + SIGNAL_FRAMESIZE + 16;
644     if (!lock_user_struct(VERIFY_READ, rt_sf, rt_sf_addr, 1))
645         goto sigsegv;
646 
647     if (do_setcontext(&rt_sf->uc, env, 1))
648         goto sigsegv;
649 
650     target_restore_altstack(&rt_sf->uc.tuc_stack, env);
651 
652     unlock_user_struct(rt_sf, rt_sf_addr, 1);
653     return -QEMU_ESIGRETURN;
654 
655 sigsegv:
656     unlock_user_struct(rt_sf, rt_sf_addr, 1);
657     force_sig(TARGET_SIGSEGV);
658     return -QEMU_ESIGRETURN;
659 }
660 
661 /* This syscall implements {get,set,swap}context for userland.  */
662 abi_long do_swapcontext(CPUArchState *env, abi_ulong uold_ctx,
663                         abi_ulong unew_ctx, abi_long ctx_size)
664 {
665     struct target_ucontext *uctx;
666     struct target_mcontext *mctx;
667 
668     /* For ppc32, ctx_size is "reserved for future use".
669      * For ppc64, we do not yet support the VSX extension.
670      */
671     if (ctx_size < sizeof(struct target_ucontext)) {
672         return -TARGET_EINVAL;
673     }
674 
675     if (uold_ctx) {
676         TaskState *ts = (TaskState *)thread_cpu->opaque;
677 
678         if (!lock_user_struct(VERIFY_WRITE, uctx, uold_ctx, 1)) {
679             return -TARGET_EFAULT;
680         }
681 
682 #ifdef TARGET_PPC64
683         mctx = &uctx->tuc_sigcontext.mcontext;
684 #else
685         /* ??? The kernel aligns the pointer down here into padding, but
686          * in setup_rt_frame we don't.  Be self-compatible for now.
687          */
688         mctx = &uctx->tuc_mcontext;
689         __put_user(h2g(mctx), &uctx->tuc_regs);
690 #endif
691 
692         save_user_regs(env, mctx);
693         host_to_target_sigset(&uctx->tuc_sigmask, &ts->signal_mask);
694 
695         unlock_user_struct(uctx, uold_ctx, 1);
696     }
697 
698     if (unew_ctx) {
699         int err;
700 
701         if (!lock_user_struct(VERIFY_READ, uctx, unew_ctx, 1)) {
702             return -TARGET_EFAULT;
703         }
704         err = do_setcontext(uctx, env, 0);
705         unlock_user_struct(uctx, unew_ctx, 1);
706 
707         if (err) {
708             /* We cannot return to a partially updated context.  */
709             force_sig(TARGET_SIGSEGV);
710         }
711         return -QEMU_ESIGRETURN;
712     }
713 
714     return 0;
715 }
716 
717 void setup_sigtramp(abi_ulong sigtramp_page)
718 {
719     uint32_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 2 * 8, 0);
720     assert(tramp != NULL);
721 
722 #ifdef TARGET_ARCH_HAS_SETUP_FRAME
723     default_sigreturn = sigtramp_page;
724     encode_trampoline(TARGET_NR_sigreturn, tramp + 0);
725 #endif
726 
727     default_rt_sigreturn = sigtramp_page + 8;
728     encode_trampoline(TARGET_NR_rt_sigreturn, tramp + 2);
729 
730     unlock_user(tramp, sigtramp_page, 2 * 8);
731 }
732