xref: /openbmc/qemu/linux-user/ppc/signal.c (revision 83a71719)
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 "signal-common.h"
22 #include "linux-user/trace.h"
23 
24 /* Size of dummy stack frame allocated when calling signal handler.
25    See arch/powerpc/include/asm/ptrace.h.  */
26 #if defined(TARGET_PPC64)
27 #define SIGNAL_FRAMESIZE 128
28 #else
29 #define SIGNAL_FRAMESIZE 64
30 #endif
31 
32 /* See arch/powerpc/include/asm/ucontext.h.  Only used for 32-bit PPC;
33    on 64-bit PPC, sigcontext and mcontext are one and the same.  */
34 struct target_mcontext {
35     target_ulong mc_gregs[48];
36     /* Includes fpscr.  */
37     uint64_t mc_fregs[33];
38 #if defined(TARGET_PPC64)
39     /* Pointer to the vector regs */
40     target_ulong v_regs;
41 #else
42     target_ulong mc_pad[2];
43 #endif
44     /* We need to handle Altivec and SPE at the same time, which no
45        kernel needs to do.  Fortunately, the kernel defines this bit to
46        be Altivec-register-large all the time, rather than trying to
47        twiddle it based on the specific platform.  */
48     union {
49         /* SPE vector registers.  One extra for SPEFSCR.  */
50         uint32_t spe[33];
51         /* Altivec vector registers.  The packing of VSCR and VRSAVE
52            varies depending on whether we're PPC64 or not: PPC64 splits
53            them apart; PPC32 stuffs them together.
54            We also need to account for the VSX registers on PPC64
55         */
56 #if defined(TARGET_PPC64)
57 #define QEMU_NVRREG (34 + 16)
58         /* On ppc64, this mcontext structure is naturally *unaligned*,
59          * or rather it is aligned on a 8 bytes boundary but not on
60          * a 16 bytes one. This pad fixes it up. This is also why the
61          * vector regs are referenced by the v_regs pointer above so
62          * any amount of padding can be added here
63          */
64         target_ulong pad;
65 #else
66         /* On ppc32, we are already aligned to 16 bytes */
67 #define QEMU_NVRREG 33
68 #endif
69         /* We cannot use ppc_avr_t here as we do *not* want the implied
70          * 16-bytes alignment that would result from it. This would have
71          * the effect of making the whole struct target_mcontext aligned
72          * which breaks the layout of struct target_ucontext on ppc64.
73          */
74         uint64_t altivec[QEMU_NVRREG][2];
75 #undef QEMU_NVRREG
76     } mc_vregs;
77 };
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 /* See arch/powerpc/kernel/signal_32.c.  */
168 struct target_sigframe {
169     struct target_sigcontext sctx;
170     struct target_mcontext mctx;
171     int32_t abigap[56];
172 };
173 
174 #if defined(TARGET_PPC64)
175 
176 #define TARGET_TRAMP_SIZE 6
177 
178 struct target_rt_sigframe {
179     /* sys_rt_sigreturn requires the ucontext be the first field */
180     struct target_ucontext uc;
181     target_ulong  _unused[2];
182     uint32_t trampoline[TARGET_TRAMP_SIZE];
183     target_ulong pinfo; /* struct siginfo __user * */
184     target_ulong puc; /* void __user * */
185     struct target_siginfo info;
186     /* 64 bit ABI allows for 288 bytes below sp before decrementing it. */
187     char abigap[288];
188 } __attribute__((aligned(16)));
189 
190 #else
191 
192 struct target_rt_sigframe {
193     struct target_siginfo info;
194     struct target_ucontext uc;
195     int32_t abigap[56];
196 };
197 
198 #endif
199 
200 #if defined(TARGET_PPC64)
201 
202 struct target_func_ptr {
203     target_ulong entry;
204     target_ulong toc;
205 };
206 
207 #endif
208 
209 /* We use the mc_pad field for the signal return trampoline.  */
210 #define tramp mc_pad
211 
212 /* See arch/powerpc/kernel/signal.c.  */
213 static target_ulong get_sigframe(struct target_sigaction *ka,
214                                  CPUPPCState *env,
215                                  int frame_size)
216 {
217     target_ulong oldsp;
218 
219     oldsp = target_sigsp(get_sp_from_cpustate(env), ka);
220 
221     return (oldsp - frame_size) & ~0xFUL;
222 }
223 
224 #if ((defined(TARGET_WORDS_BIGENDIAN) && defined(HOST_WORDS_BIGENDIAN)) || \
225      (!defined(HOST_WORDS_BIGENDIAN) && !defined(TARGET_WORDS_BIGENDIAN)))
226 #define PPC_VEC_HI      0
227 #define PPC_VEC_LO      1
228 #else
229 #define PPC_VEC_HI      1
230 #define PPC_VEC_LO      0
231 #endif
232 
233 
234 static void save_user_regs(CPUPPCState *env, struct target_mcontext *frame)
235 {
236     target_ulong msr = env->msr;
237     int i;
238     target_ulong ccr = 0;
239 
240     /* In general, the kernel attempts to be intelligent about what it
241        needs to save for Altivec/FP/SPE registers.  We don't care that
242        much, so we just go ahead and save everything.  */
243 
244     /* Save general registers.  */
245     for (i = 0; i < ARRAY_SIZE(env->gpr); i++) {
246         __put_user(env->gpr[i], &frame->mc_gregs[i]);
247     }
248     __put_user(env->nip, &frame->mc_gregs[TARGET_PT_NIP]);
249     __put_user(env->ctr, &frame->mc_gregs[TARGET_PT_CTR]);
250     __put_user(env->lr, &frame->mc_gregs[TARGET_PT_LNK]);
251     __put_user(env->xer, &frame->mc_gregs[TARGET_PT_XER]);
252 
253     for (i = 0; i < ARRAY_SIZE(env->crf); i++) {
254         ccr |= env->crf[i] << (32 - ((i + 1) * 4));
255     }
256     __put_user(ccr, &frame->mc_gregs[TARGET_PT_CCR]);
257 
258     /* Save Altivec registers if necessary.  */
259     if (env->insns_flags & PPC_ALTIVEC) {
260         uint32_t *vrsave;
261         for (i = 0; i < 32; i++) {
262             ppc_avr_t *avr = cpu_avr_ptr(env, i);
263             ppc_avr_t *vreg = (ppc_avr_t *)&frame->mc_vregs.altivec[i];
264 
265             __put_user(avr->u64[PPC_VEC_HI], &vreg->u64[0]);
266             __put_user(avr->u64[PPC_VEC_LO], &vreg->u64[1]);
267         }
268         /* Set MSR_VR in the saved MSR value to indicate that
269            frame->mc_vregs contains valid data.  */
270         msr |= MSR_VR;
271 #if defined(TARGET_PPC64)
272         vrsave = (uint32_t *)&frame->mc_vregs.altivec[33];
273         /* 64-bit needs to put a pointer to the vectors in the frame */
274         __put_user(h2g(frame->mc_vregs.altivec), &frame->v_regs);
275 #else
276         vrsave = (uint32_t *)&frame->mc_vregs.altivec[32];
277 #endif
278         __put_user((uint32_t)env->spr[SPR_VRSAVE], vrsave);
279     }
280 
281     /* Save VSX second halves */
282     if (env->insns_flags2 & PPC2_VSX) {
283         uint64_t *vsregs = (uint64_t *)&frame->mc_vregs.altivec[34];
284         for (i = 0; i < 32; i++) {
285             uint64_t *vsrl = cpu_vsrl_ptr(env, i);
286             __put_user(*vsrl, &vsregs[i]);
287         }
288     }
289 
290     /* Save floating point registers.  */
291     if (env->insns_flags & PPC_FLOAT) {
292         for (i = 0; i < 32; i++) {
293             uint64_t *fpr = cpu_fpr_ptr(env, i);
294             __put_user(*fpr, &frame->mc_fregs[i]);
295         }
296         __put_user((uint64_t) env->fpscr, &frame->mc_fregs[32]);
297     }
298 
299     /* Save SPE registers.  The kernel only saves the high half.  */
300     if (env->insns_flags & PPC_SPE) {
301 #if defined(TARGET_PPC64)
302         for (i = 0; i < ARRAY_SIZE(env->gpr); i++) {
303             __put_user(env->gpr[i] >> 32, &frame->mc_vregs.spe[i]);
304         }
305 #else
306         for (i = 0; i < ARRAY_SIZE(env->gprh); i++) {
307             __put_user(env->gprh[i], &frame->mc_vregs.spe[i]);
308         }
309 #endif
310         /* Set MSR_SPE in the saved MSR value to indicate that
311            frame->mc_vregs contains valid data.  */
312         msr |= MSR_SPE;
313         __put_user(env->spe_fscr, &frame->mc_vregs.spe[32]);
314     }
315 
316     /* Store MSR.  */
317     __put_user(msr, &frame->mc_gregs[TARGET_PT_MSR]);
318 }
319 
320 static void encode_trampoline(int sigret, uint32_t *tramp)
321 {
322     /* Set up the sigreturn trampoline: li r0,sigret; sc.  */
323     if (sigret) {
324         __put_user(0x38000000 | sigret, &tramp[0]);
325         __put_user(0x44000002, &tramp[1]);
326     }
327 }
328 
329 static void restore_user_regs(CPUPPCState *env,
330                               struct target_mcontext *frame, int sig)
331 {
332     target_ulong save_r2 = 0;
333     target_ulong msr;
334     target_ulong ccr;
335 
336     int i;
337 
338     if (!sig) {
339         save_r2 = env->gpr[2];
340     }
341 
342     /* Restore general registers.  */
343     for (i = 0; i < ARRAY_SIZE(env->gpr); i++) {
344         __get_user(env->gpr[i], &frame->mc_gregs[i]);
345     }
346     __get_user(env->nip, &frame->mc_gregs[TARGET_PT_NIP]);
347     __get_user(env->ctr, &frame->mc_gregs[TARGET_PT_CTR]);
348     __get_user(env->lr, &frame->mc_gregs[TARGET_PT_LNK]);
349     __get_user(env->xer, &frame->mc_gregs[TARGET_PT_XER]);
350     __get_user(ccr, &frame->mc_gregs[TARGET_PT_CCR]);
351 
352     for (i = 0; i < ARRAY_SIZE(env->crf); i++) {
353         env->crf[i] = (ccr >> (32 - ((i + 1) * 4))) & 0xf;
354     }
355 
356     if (!sig) {
357         env->gpr[2] = save_r2;
358     }
359     /* Restore MSR.  */
360     __get_user(msr, &frame->mc_gregs[TARGET_PT_MSR]);
361 
362     /* If doing signal return, restore the previous little-endian mode.  */
363     if (sig)
364         env->msr = (env->msr & ~(1ull << MSR_LE)) | (msr & (1ull << MSR_LE));
365 
366     /* Restore Altivec registers if necessary.  */
367     if (env->insns_flags & PPC_ALTIVEC) {
368         ppc_avr_t *v_regs;
369         uint32_t *vrsave;
370 #if defined(TARGET_PPC64)
371         uint64_t v_addr;
372         /* 64-bit needs to recover the pointer to the vectors from the frame */
373         __get_user(v_addr, &frame->v_regs);
374         v_regs = g2h(v_addr);
375 #else
376         v_regs = (ppc_avr_t *)frame->mc_vregs.altivec;
377 #endif
378         for (i = 0; i < 32; i++) {
379             ppc_avr_t *avr = cpu_avr_ptr(env, i);
380             ppc_avr_t *vreg = &v_regs[i];
381 
382             __get_user(avr->u64[PPC_VEC_HI], &vreg->u64[0]);
383             __get_user(avr->u64[PPC_VEC_LO], &vreg->u64[1]);
384         }
385         /* Set MSR_VEC in the saved MSR value to indicate that
386            frame->mc_vregs contains valid data.  */
387 #if defined(TARGET_PPC64)
388         vrsave = (uint32_t *)&v_regs[33];
389 #else
390         vrsave = (uint32_t *)&v_regs[32];
391 #endif
392         __get_user(env->spr[SPR_VRSAVE], vrsave);
393     }
394 
395     /* Restore VSX second halves */
396     if (env->insns_flags2 & PPC2_VSX) {
397         uint64_t *vsregs = (uint64_t *)&frame->mc_vregs.altivec[34];
398         for (i = 0; i < 32; i++) {
399             uint64_t *vsrl = cpu_vsrl_ptr(env, i);
400             __get_user(*vsrl, &vsregs[i]);
401         }
402     }
403 
404     /* Restore floating point registers.  */
405     if (env->insns_flags & PPC_FLOAT) {
406         uint64_t fpscr;
407         for (i = 0; i < 32; i++) {
408             uint64_t *fpr = cpu_fpr_ptr(env, i);
409             __get_user(*fpr, &frame->mc_fregs[i]);
410         }
411         __get_user(fpscr, &frame->mc_fregs[32]);
412         env->fpscr = (uint32_t) fpscr;
413     }
414 
415     /* Save SPE registers.  The kernel only saves the high half.  */
416     if (env->insns_flags & PPC_SPE) {
417 #if defined(TARGET_PPC64)
418         for (i = 0; i < ARRAY_SIZE(env->gpr); i++) {
419             uint32_t hi;
420 
421             __get_user(hi, &frame->mc_vregs.spe[i]);
422             env->gpr[i] = ((uint64_t)hi << 32) | ((uint32_t) env->gpr[i]);
423         }
424 #else
425         for (i = 0; i < ARRAY_SIZE(env->gprh); i++) {
426             __get_user(env->gprh[i], &frame->mc_vregs.spe[i]);
427         }
428 #endif
429         __get_user(env->spe_fscr, &frame->mc_vregs.spe[32]);
430     }
431 }
432 
433 #if !defined(TARGET_PPC64)
434 void setup_frame(int sig, struct target_sigaction *ka,
435                  target_sigset_t *set, CPUPPCState *env)
436 {
437     struct target_sigframe *frame;
438     struct target_sigcontext *sc;
439     target_ulong frame_addr, newsp;
440     int err = 0;
441 
442     frame_addr = get_sigframe(ka, env, sizeof(*frame));
443     trace_user_setup_frame(env, frame_addr);
444     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 1))
445         goto sigsegv;
446     sc = &frame->sctx;
447 
448     __put_user(ka->_sa_handler, &sc->handler);
449     __put_user(set->sig[0], &sc->oldmask);
450     __put_user(set->sig[1], &sc->_unused[3]);
451     __put_user(h2g(&frame->mctx), &sc->regs);
452     __put_user(sig, &sc->signal);
453 
454     /* Save user regs.  */
455     save_user_regs(env, &frame->mctx);
456 
457     /* Construct the trampoline code on the stack. */
458     encode_trampoline(TARGET_NR_sigreturn, (uint32_t *)&frame->mctx.tramp);
459 
460     /* The kernel checks for the presence of a VDSO here.  We don't
461        emulate a vdso, so use a sigreturn system call.  */
462     env->lr = (target_ulong) h2g(frame->mctx.tramp);
463 
464     /* Turn off all fp exceptions.  */
465     env->fpscr = 0;
466 
467     /* Create a stack frame for the caller of the handler.  */
468     newsp = frame_addr - SIGNAL_FRAMESIZE;
469     err |= put_user(env->gpr[1], newsp, target_ulong);
470 
471     if (err)
472         goto sigsegv;
473 
474     /* Set up registers for signal handler.  */
475     env->gpr[1] = newsp;
476     env->gpr[3] = sig;
477     env->gpr[4] = frame_addr + offsetof(struct target_sigframe, sctx);
478 
479     env->nip = (target_ulong) ka->_sa_handler;
480 
481     /* Signal handlers are entered in big-endian mode.  */
482     env->msr &= ~(1ull << MSR_LE);
483 
484     unlock_user_struct(frame, frame_addr, 1);
485     return;
486 
487 sigsegv:
488     unlock_user_struct(frame, frame_addr, 1);
489     force_sigsegv(sig);
490 }
491 #endif /* !defined(TARGET_PPC64) */
492 
493 void setup_rt_frame(int sig, struct target_sigaction *ka,
494                     target_siginfo_t *info,
495                     target_sigset_t *set, CPUPPCState *env)
496 {
497     struct target_rt_sigframe *rt_sf;
498     uint32_t *trampptr = 0;
499     struct target_mcontext *mctx = 0;
500     target_ulong rt_sf_addr, newsp = 0;
501     int i, err = 0;
502 #if defined(TARGET_PPC64)
503     struct target_sigcontext *sc = 0;
504     struct image_info *image = ((TaskState *)thread_cpu->opaque)->info;
505 #endif
506 
507     rt_sf_addr = get_sigframe(ka, env, sizeof(*rt_sf));
508     if (!lock_user_struct(VERIFY_WRITE, rt_sf, rt_sf_addr, 1))
509         goto sigsegv;
510 
511     tswap_siginfo(&rt_sf->info, info);
512 
513     __put_user(0, &rt_sf->uc.tuc_flags);
514     __put_user(0, &rt_sf->uc.tuc_link);
515     target_save_altstack(&rt_sf->uc.tuc_stack, env);
516 #if !defined(TARGET_PPC64)
517     __put_user(h2g (&rt_sf->uc.tuc_mcontext),
518                &rt_sf->uc.tuc_regs);
519 #endif
520     for(i = 0; i < TARGET_NSIG_WORDS; i++) {
521         __put_user(set->sig[i], &rt_sf->uc.tuc_sigmask.sig[i]);
522     }
523 
524 #if defined(TARGET_PPC64)
525     mctx = &rt_sf->uc.tuc_sigcontext.mcontext;
526     trampptr = &rt_sf->trampoline[0];
527 
528     sc = &rt_sf->uc.tuc_sigcontext;
529     __put_user(h2g(mctx), &sc->regs);
530     __put_user(sig, &sc->signal);
531 #else
532     mctx = &rt_sf->uc.tuc_mcontext;
533     trampptr = (uint32_t *)&rt_sf->uc.tuc_mcontext.tramp;
534 #endif
535 
536     save_user_regs(env, mctx);
537     encode_trampoline(TARGET_NR_rt_sigreturn, trampptr);
538 
539     /* The kernel checks for the presence of a VDSO here.  We don't
540        emulate a vdso, so use a sigreturn system call.  */
541     env->lr = (target_ulong) h2g(trampptr);
542 
543     /* Turn off all fp exceptions.  */
544     env->fpscr = 0;
545 
546     /* Create a stack frame for the caller of the handler.  */
547     newsp = rt_sf_addr - (SIGNAL_FRAMESIZE + 16);
548     err |= put_user(env->gpr[1], newsp, target_ulong);
549 
550     if (err)
551         goto sigsegv;
552 
553     /* Set up registers for signal handler.  */
554     env->gpr[1] = newsp;
555     env->gpr[3] = (target_ulong) sig;
556     env->gpr[4] = (target_ulong) h2g(&rt_sf->info);
557     env->gpr[5] = (target_ulong) h2g(&rt_sf->uc);
558     env->gpr[6] = (target_ulong) h2g(rt_sf);
559 
560 #if defined(TARGET_PPC64)
561     if (get_ppc64_abi(image) < 2) {
562         /* ELFv1 PPC64 function pointers are pointers to OPD entries. */
563         struct target_func_ptr *handler =
564             (struct target_func_ptr *)g2h(ka->_sa_handler);
565         env->nip = tswapl(handler->entry);
566         env->gpr[2] = tswapl(handler->toc);
567     } else {
568         /* ELFv2 PPC64 function pointers are entry points, but R12
569          * must also be set */
570         env->nip = tswapl((target_ulong) ka->_sa_handler);
571         env->gpr[12] = env->nip;
572     }
573 #else
574     env->nip = (target_ulong) ka->_sa_handler;
575 #endif
576 
577     /* Signal handlers are entered in big-endian mode.  */
578     env->msr &= ~(1ull << MSR_LE);
579 
580     unlock_user_struct(rt_sf, rt_sf_addr, 1);
581     return;
582 
583 sigsegv:
584     unlock_user_struct(rt_sf, rt_sf_addr, 1);
585     force_sigsegv(sig);
586 
587 }
588 
589 #if !defined(TARGET_PPC64)
590 long do_sigreturn(CPUPPCState *env)
591 {
592     struct target_sigcontext *sc = NULL;
593     struct target_mcontext *sr = NULL;
594     target_ulong sr_addr = 0, sc_addr;
595     sigset_t blocked;
596     target_sigset_t set;
597 
598     sc_addr = env->gpr[1] + SIGNAL_FRAMESIZE;
599     if (!lock_user_struct(VERIFY_READ, sc, sc_addr, 1))
600         goto sigsegv;
601 
602 #if defined(TARGET_PPC64)
603     set.sig[0] = sc->oldmask + ((uint64_t)(sc->_unused[3]) << 32);
604 #else
605     __get_user(set.sig[0], &sc->oldmask);
606     __get_user(set.sig[1], &sc->_unused[3]);
607 #endif
608     target_to_host_sigset_internal(&blocked, &set);
609     set_sigmask(&blocked);
610 
611     __get_user(sr_addr, &sc->regs);
612     if (!lock_user_struct(VERIFY_READ, sr, sr_addr, 1))
613         goto sigsegv;
614     restore_user_regs(env, sr, 1);
615 
616     unlock_user_struct(sr, sr_addr, 1);
617     unlock_user_struct(sc, sc_addr, 1);
618     return -TARGET_QEMU_ESIGRETURN;
619 
620 sigsegv:
621     unlock_user_struct(sr, sr_addr, 1);
622     unlock_user_struct(sc, sc_addr, 1);
623     force_sig(TARGET_SIGSEGV);
624     return -TARGET_QEMU_ESIGRETURN;
625 }
626 #endif /* !defined(TARGET_PPC64) */
627 
628 /* See arch/powerpc/kernel/signal_32.c.  */
629 static int do_setcontext(struct target_ucontext *ucp, CPUPPCState *env, int sig)
630 {
631     struct target_mcontext *mcp;
632     target_ulong mcp_addr;
633     sigset_t blocked;
634     target_sigset_t set;
635 
636     if (copy_from_user(&set, h2g(ucp) + offsetof(struct target_ucontext, tuc_sigmask),
637                        sizeof (set)))
638         return 1;
639 
640 #if defined(TARGET_PPC64)
641     mcp_addr = h2g(ucp) +
642         offsetof(struct target_ucontext, tuc_sigcontext.mcontext);
643 #else
644     __get_user(mcp_addr, &ucp->tuc_regs);
645 #endif
646 
647     if (!lock_user_struct(VERIFY_READ, mcp, mcp_addr, 1))
648         return 1;
649 
650     target_to_host_sigset_internal(&blocked, &set);
651     set_sigmask(&blocked);
652     restore_user_regs(env, mcp, sig);
653 
654     unlock_user_struct(mcp, mcp_addr, 1);
655     return 0;
656 }
657 
658 long do_rt_sigreturn(CPUPPCState *env)
659 {
660     struct target_rt_sigframe *rt_sf = NULL;
661     target_ulong rt_sf_addr;
662 
663     rt_sf_addr = env->gpr[1] + SIGNAL_FRAMESIZE + 16;
664     if (!lock_user_struct(VERIFY_READ, rt_sf, rt_sf_addr, 1))
665         goto sigsegv;
666 
667     if (do_setcontext(&rt_sf->uc, env, 1))
668         goto sigsegv;
669 
670     do_sigaltstack(rt_sf_addr
671                    + offsetof(struct target_rt_sigframe, uc.tuc_stack),
672                    0, env->gpr[1]);
673 
674     unlock_user_struct(rt_sf, rt_sf_addr, 1);
675     return -TARGET_QEMU_ESIGRETURN;
676 
677 sigsegv:
678     unlock_user_struct(rt_sf, rt_sf_addr, 1);
679     force_sig(TARGET_SIGSEGV);
680     return -TARGET_QEMU_ESIGRETURN;
681 }
682 
683 /* This syscall implements {get,set,swap}context for userland.  */
684 abi_long do_swapcontext(CPUArchState *env, abi_ulong uold_ctx,
685                         abi_ulong unew_ctx, abi_long ctx_size)
686 {
687     struct target_ucontext *uctx;
688     struct target_mcontext *mctx;
689 
690     /* For ppc32, ctx_size is "reserved for future use".
691      * For ppc64, we do not yet support the VSX extension.
692      */
693     if (ctx_size < sizeof(struct target_ucontext)) {
694         return -TARGET_EINVAL;
695     }
696 
697     if (uold_ctx) {
698         TaskState *ts = (TaskState *)thread_cpu->opaque;
699 
700         if (!lock_user_struct(VERIFY_WRITE, uctx, uold_ctx, 1)) {
701             return -TARGET_EFAULT;
702         }
703 
704 #ifdef TARGET_PPC64
705         mctx = &uctx->tuc_sigcontext.mcontext;
706 #else
707         /* ??? The kernel aligns the pointer down here into padding, but
708          * in setup_rt_frame we don't.  Be self-compatible for now.
709          */
710         mctx = &uctx->tuc_mcontext;
711         __put_user(h2g(mctx), &uctx->tuc_regs);
712 #endif
713 
714         save_user_regs(env, mctx);
715         host_to_target_sigset(&uctx->tuc_sigmask, &ts->signal_mask);
716 
717         unlock_user_struct(uctx, uold_ctx, 1);
718     }
719 
720     if (unew_ctx) {
721         int err;
722 
723         if (!lock_user_struct(VERIFY_READ, uctx, unew_ctx, 1)) {
724             return -TARGET_EFAULT;
725         }
726         err = do_setcontext(uctx, env, 0);
727         unlock_user_struct(uctx, unew_ctx, 1);
728 
729         if (err) {
730             /* We cannot return to a partially updated context.  */
731             force_sig(TARGET_SIGSEGV);
732         }
733         return -TARGET_QEMU_ESIGRETURN;
734     }
735 
736     return 0;
737 }
738