xref: /openbmc/qemu/linux-user/ppc/signal.c (revision 2f44bea9)
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 /* We use the mc_pad field for the signal return trampoline.  */
207 #define tramp mc_pad
208 
209 /* See arch/powerpc/kernel/signal.c.  */
210 static target_ulong get_sigframe(struct target_sigaction *ka,
211                                  CPUPPCState *env,
212                                  int frame_size)
213 {
214     target_ulong oldsp;
215 
216     oldsp = target_sigsp(get_sp_from_cpustate(env), ka);
217 
218     return (oldsp - frame_size) & ~0xFUL;
219 }
220 
221 #if ((defined(TARGET_WORDS_BIGENDIAN) && defined(HOST_WORDS_BIGENDIAN)) || \
222      (!defined(HOST_WORDS_BIGENDIAN) && !defined(TARGET_WORDS_BIGENDIAN)))
223 #define PPC_VEC_HI      0
224 #define PPC_VEC_LO      1
225 #else
226 #define PPC_VEC_HI      1
227 #define PPC_VEC_LO      0
228 #endif
229 
230 
231 static void save_user_regs(CPUPPCState *env, struct target_mcontext *frame)
232 {
233     target_ulong msr = env->msr;
234     int i;
235     target_ulong ccr = 0;
236 
237     /* In general, the kernel attempts to be intelligent about what it
238        needs to save for Altivec/FP/SPE registers.  We don't care that
239        much, so we just go ahead and save everything.  */
240 
241     /* Save general registers.  */
242     for (i = 0; i < ARRAY_SIZE(env->gpr); i++) {
243         __put_user(env->gpr[i], &frame->mc_gregs[i]);
244     }
245     __put_user(env->nip, &frame->mc_gregs[TARGET_PT_NIP]);
246     __put_user(env->ctr, &frame->mc_gregs[TARGET_PT_CTR]);
247     __put_user(env->lr, &frame->mc_gregs[TARGET_PT_LNK]);
248     __put_user(env->xer, &frame->mc_gregs[TARGET_PT_XER]);
249 
250     for (i = 0; i < ARRAY_SIZE(env->crf); i++) {
251         ccr |= env->crf[i] << (32 - ((i + 1) * 4));
252     }
253     __put_user(ccr, &frame->mc_gregs[TARGET_PT_CCR]);
254 
255     /* Save Altivec registers if necessary.  */
256     if (env->insns_flags & PPC_ALTIVEC) {
257         uint32_t *vrsave;
258         for (i = 0; i < 32; i++) {
259             ppc_avr_t *avr = cpu_avr_ptr(env, i);
260             ppc_avr_t *vreg = (ppc_avr_t *)&frame->mc_vregs.altivec[i];
261 
262             __put_user(avr->u64[PPC_VEC_HI], &vreg->u64[0]);
263             __put_user(avr->u64[PPC_VEC_LO], &vreg->u64[1]);
264         }
265 #if defined(TARGET_PPC64)
266         vrsave = (uint32_t *)&frame->mc_vregs.altivec[33];
267         /* 64-bit needs to put a pointer to the vectors in the frame */
268         __put_user(h2g(frame->mc_vregs.altivec), &frame->v_regs);
269 #else
270         vrsave = (uint32_t *)&frame->mc_vregs.altivec[32];
271 #endif
272         __put_user((uint32_t)env->spr[SPR_VRSAVE], vrsave);
273     }
274 
275 #if defined(TARGET_PPC64)
276     /* Save VSX second halves */
277     if (env->insns_flags2 & PPC2_VSX) {
278         uint64_t *vsregs = (uint64_t *)&frame->mc_vregs.altivec[34];
279         for (i = 0; i < 32; i++) {
280             uint64_t *vsrl = cpu_vsrl_ptr(env, i);
281             __put_user(*vsrl, &vsregs[i]);
282         }
283     }
284 #endif
285 
286     /* Save floating point registers.  */
287     if (env->insns_flags & PPC_FLOAT) {
288         for (i = 0; i < 32; i++) {
289             uint64_t *fpr = cpu_fpr_ptr(env, i);
290             __put_user(*fpr, &frame->mc_fregs[i]);
291         }
292         __put_user((uint64_t) env->fpscr, &frame->mc_fregs[32]);
293     }
294 
295 #if !defined(TARGET_PPC64)
296     /* Save SPE registers.  The kernel only saves the high half.  */
297     if (env->insns_flags & PPC_SPE) {
298         for (i = 0; i < ARRAY_SIZE(env->gprh); i++) {
299             __put_user(env->gprh[i], &frame->mc_vregs.spe[i]);
300         }
301         __put_user(env->spe_fscr, &frame->mc_vregs.spe[32]);
302     }
303 #endif
304 
305     /* Store MSR.  */
306     __put_user(msr, &frame->mc_gregs[TARGET_PT_MSR]);
307 }
308 
309 static void encode_trampoline(int sigret, uint32_t *tramp)
310 {
311     /* Set up the sigreturn trampoline: li r0,sigret; sc.  */
312     if (sigret) {
313         __put_user(0x38000000 | sigret, &tramp[0]);
314         __put_user(0x44000002, &tramp[1]);
315     }
316 }
317 
318 static void restore_user_regs(CPUPPCState *env,
319                               struct target_mcontext *frame, int sig)
320 {
321     target_ulong save_r2 = 0;
322     target_ulong msr;
323     target_ulong ccr;
324 
325     int i;
326 
327     if (!sig) {
328         save_r2 = env->gpr[2];
329     }
330 
331     /* Restore general registers.  */
332     for (i = 0; i < ARRAY_SIZE(env->gpr); i++) {
333         __get_user(env->gpr[i], &frame->mc_gregs[i]);
334     }
335     __get_user(env->nip, &frame->mc_gregs[TARGET_PT_NIP]);
336     __get_user(env->ctr, &frame->mc_gregs[TARGET_PT_CTR]);
337     __get_user(env->lr, &frame->mc_gregs[TARGET_PT_LNK]);
338     __get_user(env->xer, &frame->mc_gregs[TARGET_PT_XER]);
339     __get_user(ccr, &frame->mc_gregs[TARGET_PT_CCR]);
340 
341     for (i = 0; i < ARRAY_SIZE(env->crf); i++) {
342         env->crf[i] = (ccr >> (32 - ((i + 1) * 4))) & 0xf;
343     }
344 
345     if (!sig) {
346         env->gpr[2] = save_r2;
347     }
348     /* Restore MSR.  */
349     __get_user(msr, &frame->mc_gregs[TARGET_PT_MSR]);
350 
351     /* If doing signal return, restore the previous little-endian mode.  */
352     if (sig) {
353         ppc_store_msr(env, ((env->msr & ~(1ull << MSR_LE)) |
354                             (msr & (1ull << MSR_LE))));
355     }
356 
357     /* Restore Altivec registers if necessary.  */
358     if (env->insns_flags & PPC_ALTIVEC) {
359         ppc_avr_t *v_regs;
360         uint32_t *vrsave;
361 #if defined(TARGET_PPC64)
362         uint64_t v_addr;
363         /* 64-bit needs to recover the pointer to the vectors from the frame */
364         __get_user(v_addr, &frame->v_regs);
365         v_regs = g2h(env_cpu(env), v_addr);
366 #else
367         v_regs = (ppc_avr_t *)frame->mc_vregs.altivec;
368 #endif
369         for (i = 0; i < 32; i++) {
370             ppc_avr_t *avr = cpu_avr_ptr(env, i);
371             ppc_avr_t *vreg = &v_regs[i];
372 
373             __get_user(avr->u64[PPC_VEC_HI], &vreg->u64[0]);
374             __get_user(avr->u64[PPC_VEC_LO], &vreg->u64[1]);
375         }
376 #if defined(TARGET_PPC64)
377         vrsave = (uint32_t *)&v_regs[33];
378 #else
379         vrsave = (uint32_t *)&v_regs[32];
380 #endif
381         __get_user(env->spr[SPR_VRSAVE], vrsave);
382     }
383 
384 #if defined(TARGET_PPC64)
385     /* Restore VSX second halves */
386     if (env->insns_flags2 & PPC2_VSX) {
387         uint64_t *vsregs = (uint64_t *)&frame->mc_vregs.altivec[34];
388         for (i = 0; i < 32; i++) {
389             uint64_t *vsrl = cpu_vsrl_ptr(env, i);
390             __get_user(*vsrl, &vsregs[i]);
391         }
392     }
393 #endif
394 
395     /* Restore floating point registers.  */
396     if (env->insns_flags & PPC_FLOAT) {
397         uint64_t fpscr;
398         for (i = 0; i < 32; i++) {
399             uint64_t *fpr = cpu_fpr_ptr(env, i);
400             __get_user(*fpr, &frame->mc_fregs[i]);
401         }
402         __get_user(fpscr, &frame->mc_fregs[32]);
403         env->fpscr = (uint32_t) fpscr;
404     }
405 
406 #if !defined(TARGET_PPC64)
407     /* Save SPE registers.  The kernel only saves the high half.  */
408     if (env->insns_flags & PPC_SPE) {
409         for (i = 0; i < ARRAY_SIZE(env->gprh); i++) {
410             __get_user(env->gprh[i], &frame->mc_vregs.spe[i]);
411         }
412         __get_user(env->spe_fscr, &frame->mc_vregs.spe[32]);
413     }
414 #endif
415 }
416 
417 #if !defined(TARGET_PPC64)
418 void setup_frame(int sig, struct target_sigaction *ka,
419                  target_sigset_t *set, CPUPPCState *env)
420 {
421     struct target_sigframe *frame;
422     struct target_sigcontext *sc;
423     target_ulong frame_addr, newsp;
424     int err = 0;
425 
426     frame_addr = get_sigframe(ka, env, sizeof(*frame));
427     trace_user_setup_frame(env, frame_addr);
428     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 1))
429         goto sigsegv;
430     sc = &frame->sctx;
431 
432     __put_user(ka->_sa_handler, &sc->handler);
433     __put_user(set->sig[0], &sc->oldmask);
434     __put_user(set->sig[1], &sc->_unused[3]);
435     __put_user(h2g(&frame->mctx), &sc->regs);
436     __put_user(sig, &sc->signal);
437 
438     /* Save user regs.  */
439     save_user_regs(env, &frame->mctx);
440 
441     /* Construct the trampoline code on the stack. */
442     encode_trampoline(TARGET_NR_sigreturn, (uint32_t *)&frame->mctx.tramp);
443 
444     /* The kernel checks for the presence of a VDSO here.  We don't
445        emulate a vdso, so use a sigreturn system call.  */
446     env->lr = (target_ulong) h2g(frame->mctx.tramp);
447 
448     /* Turn off all fp exceptions.  */
449     env->fpscr = 0;
450 
451     /* Create a stack frame for the caller of the handler.  */
452     newsp = frame_addr - SIGNAL_FRAMESIZE;
453     err |= put_user(env->gpr[1], newsp, target_ulong);
454 
455     if (err)
456         goto sigsegv;
457 
458     /* Set up registers for signal handler.  */
459     env->gpr[1] = newsp;
460     env->gpr[3] = sig;
461     env->gpr[4] = frame_addr + offsetof(struct target_sigframe, sctx);
462 
463     env->nip = (target_ulong) ka->_sa_handler;
464 
465     /* Signal handlers are entered in big-endian mode.  */
466     ppc_store_msr(env, env->msr & ~(1ull << MSR_LE));
467 
468     unlock_user_struct(frame, frame_addr, 1);
469     return;
470 
471 sigsegv:
472     unlock_user_struct(frame, frame_addr, 1);
473     force_sigsegv(sig);
474 }
475 #endif /* !defined(TARGET_PPC64) */
476 
477 void setup_rt_frame(int sig, struct target_sigaction *ka,
478                     target_siginfo_t *info,
479                     target_sigset_t *set, CPUPPCState *env)
480 {
481     struct target_rt_sigframe *rt_sf;
482     uint32_t *trampptr = 0;
483     struct target_mcontext *mctx = 0;
484     target_ulong rt_sf_addr, newsp = 0;
485     int i, err = 0;
486 #if defined(TARGET_PPC64)
487     struct target_sigcontext *sc = 0;
488 #if !defined(TARGET_ABI32)
489     struct image_info *image = ((TaskState *)thread_cpu->opaque)->info;
490 #endif
491 #endif
492 
493     rt_sf_addr = get_sigframe(ka, env, sizeof(*rt_sf));
494     if (!lock_user_struct(VERIFY_WRITE, rt_sf, rt_sf_addr, 1))
495         goto sigsegv;
496 
497     tswap_siginfo(&rt_sf->info, info);
498 
499     __put_user(0, &rt_sf->uc.tuc_flags);
500     __put_user(0, &rt_sf->uc.tuc_link);
501     target_save_altstack(&rt_sf->uc.tuc_stack, env);
502 #if !defined(TARGET_PPC64)
503     __put_user(h2g (&rt_sf->uc.tuc_mcontext),
504                &rt_sf->uc.tuc_regs);
505 #endif
506     for(i = 0; i < TARGET_NSIG_WORDS; i++) {
507         __put_user(set->sig[i], &rt_sf->uc.tuc_sigmask.sig[i]);
508     }
509 
510 #if defined(TARGET_PPC64)
511     mctx = &rt_sf->uc.tuc_sigcontext.mcontext;
512     trampptr = &rt_sf->trampoline[0];
513 
514     sc = &rt_sf->uc.tuc_sigcontext;
515     __put_user(h2g(mctx), &sc->regs);
516     __put_user(sig, &sc->signal);
517 #else
518     mctx = &rt_sf->uc.tuc_mcontext;
519     trampptr = (uint32_t *)&rt_sf->uc.tuc_mcontext.tramp;
520 #endif
521 
522     save_user_regs(env, mctx);
523     encode_trampoline(TARGET_NR_rt_sigreturn, trampptr);
524 
525     /* The kernel checks for the presence of a VDSO here.  We don't
526        emulate a vdso, so use a sigreturn system call.  */
527     env->lr = (target_ulong) h2g(trampptr);
528 
529     /* Turn off all fp exceptions.  */
530     env->fpscr = 0;
531 
532     /* Create a stack frame for the caller of the handler.  */
533     newsp = rt_sf_addr - (SIGNAL_FRAMESIZE + 16);
534     err |= put_user(env->gpr[1], newsp, target_ulong);
535 
536     if (err)
537         goto sigsegv;
538 
539     /* Set up registers for signal handler.  */
540     env->gpr[1] = newsp;
541     env->gpr[3] = (target_ulong) sig;
542     env->gpr[4] = (target_ulong) h2g(&rt_sf->info);
543     env->gpr[5] = (target_ulong) h2g(&rt_sf->uc);
544     env->gpr[6] = (target_ulong) h2g(rt_sf);
545 
546 #if defined(TARGET_PPC64) && !defined(TARGET_ABI32)
547     if (get_ppc64_abi(image) < 2) {
548         /* ELFv1 PPC64 function pointers are pointers to OPD entries. */
549         struct target_func_ptr *handler =
550             (struct target_func_ptr *)g2h(env_cpu(env), ka->_sa_handler);
551         env->nip = tswapl(handler->entry);
552         env->gpr[2] = tswapl(handler->toc);
553     } else {
554         /* ELFv2 PPC64 function pointers are entry points. R12 must also be set. */
555         env->gpr[12] = env->nip = ka->_sa_handler;
556     }
557 #else
558     env->nip = (target_ulong) ka->_sa_handler;
559 #endif
560 
561 #ifdef TARGET_WORDS_BIGENDIAN
562     /* Signal handlers are entered in big-endian mode.  */
563     ppc_store_msr(env, env->msr & ~(1ull << MSR_LE));
564 #else
565     /* Signal handlers are entered in little-endian mode.  */
566     ppc_store_msr(env, env->msr | (1ull << MSR_LE));
567 #endif
568 
569     unlock_user_struct(rt_sf, rt_sf_addr, 1);
570     return;
571 
572 sigsegv:
573     unlock_user_struct(rt_sf, rt_sf_addr, 1);
574     force_sigsegv(sig);
575 
576 }
577 
578 #if !defined(TARGET_PPC64) || defined(TARGET_ABI32)
579 long do_sigreturn(CPUPPCState *env)
580 {
581     struct target_sigcontext *sc = NULL;
582     struct target_mcontext *sr = NULL;
583     target_ulong sr_addr = 0, sc_addr;
584     sigset_t blocked;
585     target_sigset_t set;
586 
587     sc_addr = env->gpr[1] + SIGNAL_FRAMESIZE;
588     if (!lock_user_struct(VERIFY_READ, sc, sc_addr, 1))
589         goto sigsegv;
590 
591 #if defined(TARGET_PPC64)
592     set.sig[0] = sc->oldmask + ((uint64_t)(sc->_unused[3]) << 32);
593 #else
594     __get_user(set.sig[0], &sc->oldmask);
595     __get_user(set.sig[1], &sc->_unused[3]);
596 #endif
597     target_to_host_sigset_internal(&blocked, &set);
598     set_sigmask(&blocked);
599 
600     __get_user(sr_addr, &sc->regs);
601     if (!lock_user_struct(VERIFY_READ, sr, sr_addr, 1))
602         goto sigsegv;
603     restore_user_regs(env, sr, 1);
604 
605     unlock_user_struct(sr, sr_addr, 1);
606     unlock_user_struct(sc, sc_addr, 1);
607     return -TARGET_QEMU_ESIGRETURN;
608 
609 sigsegv:
610     unlock_user_struct(sr, sr_addr, 1);
611     unlock_user_struct(sc, sc_addr, 1);
612     force_sig(TARGET_SIGSEGV);
613     return -TARGET_QEMU_ESIGRETURN;
614 }
615 #endif /* !defined(TARGET_PPC64) */
616 
617 /* See arch/powerpc/kernel/signal_32.c.  */
618 static int do_setcontext(struct target_ucontext *ucp, CPUPPCState *env, int sig)
619 {
620     struct target_mcontext *mcp;
621     target_ulong mcp_addr;
622     sigset_t blocked;
623     target_sigset_t set;
624 
625     if (copy_from_user(&set, h2g(ucp) + offsetof(struct target_ucontext, tuc_sigmask),
626                        sizeof (set)))
627         return 1;
628 
629 #if defined(TARGET_PPC64)
630     mcp_addr = h2g(ucp) +
631         offsetof(struct target_ucontext, tuc_sigcontext.mcontext);
632 #else
633     __get_user(mcp_addr, &ucp->tuc_regs);
634 #endif
635 
636     if (!lock_user_struct(VERIFY_READ, mcp, mcp_addr, 1))
637         return 1;
638 
639     target_to_host_sigset_internal(&blocked, &set);
640     set_sigmask(&blocked);
641     restore_user_regs(env, mcp, sig);
642 
643     unlock_user_struct(mcp, mcp_addr, 1);
644     return 0;
645 }
646 
647 long do_rt_sigreturn(CPUPPCState *env)
648 {
649     struct target_rt_sigframe *rt_sf = NULL;
650     target_ulong rt_sf_addr;
651 
652     rt_sf_addr = env->gpr[1] + SIGNAL_FRAMESIZE + 16;
653     if (!lock_user_struct(VERIFY_READ, rt_sf, rt_sf_addr, 1))
654         goto sigsegv;
655 
656     if (do_setcontext(&rt_sf->uc, env, 1))
657         goto sigsegv;
658 
659     target_restore_altstack(&rt_sf->uc.tuc_stack, env);
660 
661     unlock_user_struct(rt_sf, rt_sf_addr, 1);
662     return -TARGET_QEMU_ESIGRETURN;
663 
664 sigsegv:
665     unlock_user_struct(rt_sf, rt_sf_addr, 1);
666     force_sig(TARGET_SIGSEGV);
667     return -TARGET_QEMU_ESIGRETURN;
668 }
669 
670 /* This syscall implements {get,set,swap}context for userland.  */
671 abi_long do_swapcontext(CPUArchState *env, abi_ulong uold_ctx,
672                         abi_ulong unew_ctx, abi_long ctx_size)
673 {
674     struct target_ucontext *uctx;
675     struct target_mcontext *mctx;
676 
677     /* For ppc32, ctx_size is "reserved for future use".
678      * For ppc64, we do not yet support the VSX extension.
679      */
680     if (ctx_size < sizeof(struct target_ucontext)) {
681         return -TARGET_EINVAL;
682     }
683 
684     if (uold_ctx) {
685         TaskState *ts = (TaskState *)thread_cpu->opaque;
686 
687         if (!lock_user_struct(VERIFY_WRITE, uctx, uold_ctx, 1)) {
688             return -TARGET_EFAULT;
689         }
690 
691 #ifdef TARGET_PPC64
692         mctx = &uctx->tuc_sigcontext.mcontext;
693 #else
694         /* ??? The kernel aligns the pointer down here into padding, but
695          * in setup_rt_frame we don't.  Be self-compatible for now.
696          */
697         mctx = &uctx->tuc_mcontext;
698         __put_user(h2g(mctx), &uctx->tuc_regs);
699 #endif
700 
701         save_user_regs(env, mctx);
702         host_to_target_sigset(&uctx->tuc_sigmask, &ts->signal_mask);
703 
704         unlock_user_struct(uctx, uold_ctx, 1);
705     }
706 
707     if (unew_ctx) {
708         int err;
709 
710         if (!lock_user_struct(VERIFY_READ, uctx, unew_ctx, 1)) {
711             return -TARGET_EFAULT;
712         }
713         err = do_setcontext(uctx, env, 0);
714         unlock_user_struct(uctx, unew_ctx, 1);
715 
716         if (err) {
717             /* We cannot return to a partially updated context.  */
718             force_sig(TARGET_SIGSEGV);
719         }
720         return -TARGET_QEMU_ESIGRETURN;
721     }
722 
723     return 0;
724 }
725