xref: /openbmc/qemu/linux-user/ppc/signal.c (revision 4011a686)
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 
39 #if defined(TARGET_PPC64)
40     /* Pointer to the vector regs */
41     target_ulong v_regs;
42     /*
43      * On ppc64, this mcontext structure is naturally *unaligned*,
44      * or rather it is aligned on a 8 bytes boundary but not on
45      * a 16 byte boundary.  This pad fixes it up.  This is why we
46      * cannot use ppc_avr_t, which would force alignment.  This is
47      * also why the vector regs are referenced in the ABI by the
48      * v_regs pointer above so any amount of padding can be added here.
49      */
50     target_ulong pad;
51     /* VSCR and VRSAVE are saved separately.  Also reserve space for VSX. */
52     struct {
53         uint64_t altivec[34 + 16][2];
54     } mc_vregs;
55 #else
56     target_ulong mc_pad[2];
57 
58     /* We need to handle Altivec and SPE at the same time, which no
59        kernel needs to do.  Fortunately, the kernel defines this bit to
60        be Altivec-register-large all the time, rather than trying to
61        twiddle it based on the specific platform.  */
62     union {
63         /* SPE vector registers.  One extra for SPEFSCR.  */
64         uint32_t spe[33];
65         /*
66          * Altivec vector registers.  One extra for VRSAVE.
67          * On ppc32, we are already aligned to 16 bytes.  We could
68          * use ppc_avr_t, but choose to share the same type as ppc64.
69          */
70         uint64_t altivec[33][2];
71     } mc_vregs;
72 #endif
73 };
74 
75 /* See arch/powerpc/include/asm/sigcontext.h.  */
76 struct target_sigcontext {
77     target_ulong _unused[4];
78     int32_t signal;
79 #if defined(TARGET_PPC64)
80     int32_t pad0;
81 #endif
82     target_ulong handler;
83     target_ulong oldmask;
84     target_ulong regs;      /* struct pt_regs __user * */
85 #if defined(TARGET_PPC64)
86     struct target_mcontext mcontext;
87 #endif
88 };
89 
90 /* Indices for target_mcontext.mc_gregs, below.
91    See arch/powerpc/include/asm/ptrace.h for details.  */
92 enum {
93     TARGET_PT_R0 = 0,
94     TARGET_PT_R1 = 1,
95     TARGET_PT_R2 = 2,
96     TARGET_PT_R3 = 3,
97     TARGET_PT_R4 = 4,
98     TARGET_PT_R5 = 5,
99     TARGET_PT_R6 = 6,
100     TARGET_PT_R7 = 7,
101     TARGET_PT_R8 = 8,
102     TARGET_PT_R9 = 9,
103     TARGET_PT_R10 = 10,
104     TARGET_PT_R11 = 11,
105     TARGET_PT_R12 = 12,
106     TARGET_PT_R13 = 13,
107     TARGET_PT_R14 = 14,
108     TARGET_PT_R15 = 15,
109     TARGET_PT_R16 = 16,
110     TARGET_PT_R17 = 17,
111     TARGET_PT_R18 = 18,
112     TARGET_PT_R19 = 19,
113     TARGET_PT_R20 = 20,
114     TARGET_PT_R21 = 21,
115     TARGET_PT_R22 = 22,
116     TARGET_PT_R23 = 23,
117     TARGET_PT_R24 = 24,
118     TARGET_PT_R25 = 25,
119     TARGET_PT_R26 = 26,
120     TARGET_PT_R27 = 27,
121     TARGET_PT_R28 = 28,
122     TARGET_PT_R29 = 29,
123     TARGET_PT_R30 = 30,
124     TARGET_PT_R31 = 31,
125     TARGET_PT_NIP = 32,
126     TARGET_PT_MSR = 33,
127     TARGET_PT_ORIG_R3 = 34,
128     TARGET_PT_CTR = 35,
129     TARGET_PT_LNK = 36,
130     TARGET_PT_XER = 37,
131     TARGET_PT_CCR = 38,
132     /* Yes, there are two registers with #39.  One is 64-bit only.  */
133     TARGET_PT_MQ = 39,
134     TARGET_PT_SOFTE = 39,
135     TARGET_PT_TRAP = 40,
136     TARGET_PT_DAR = 41,
137     TARGET_PT_DSISR = 42,
138     TARGET_PT_RESULT = 43,
139     TARGET_PT_REGS_COUNT = 44
140 };
141 
142 
143 struct target_ucontext {
144     target_ulong tuc_flags;
145     target_ulong tuc_link;    /* ucontext_t __user * */
146     struct target_sigaltstack tuc_stack;
147 #if !defined(TARGET_PPC64)
148     int32_t tuc_pad[7];
149     target_ulong tuc_regs;    /* struct mcontext __user *
150                                 points to uc_mcontext field */
151 #endif
152     target_sigset_t tuc_sigmask;
153 #if defined(TARGET_PPC64)
154     target_sigset_t unused[15]; /* Allow for uc_sigmask growth */
155     struct target_sigcontext tuc_sigcontext;
156 #else
157     int32_t tuc_maskext[30];
158     int32_t tuc_pad2[3];
159     struct target_mcontext tuc_mcontext;
160 #endif
161 };
162 
163 /* See arch/powerpc/kernel/signal_32.c.  */
164 struct target_sigframe {
165     struct target_sigcontext sctx;
166     struct target_mcontext mctx;
167     int32_t abigap[56];
168 };
169 
170 #if defined(TARGET_PPC64)
171 
172 #define TARGET_TRAMP_SIZE 6
173 
174 struct target_rt_sigframe {
175     /* sys_rt_sigreturn requires the ucontext be the first field */
176     struct target_ucontext uc;
177     target_ulong  _unused[2];
178     uint32_t trampoline[TARGET_TRAMP_SIZE];
179     target_ulong pinfo; /* struct siginfo __user * */
180     target_ulong puc; /* void __user * */
181     struct target_siginfo info;
182     /* 64 bit ABI allows for 288 bytes below sp before decrementing it. */
183     char abigap[288];
184 } __attribute__((aligned(16)));
185 
186 #else
187 
188 struct target_rt_sigframe {
189     struct target_siginfo info;
190     struct target_ucontext uc;
191     int32_t abigap[56];
192 };
193 
194 #endif
195 
196 #if defined(TARGET_PPC64)
197 
198 struct target_func_ptr {
199     target_ulong entry;
200     target_ulong toc;
201 };
202 
203 #endif
204 
205 /* We use the mc_pad field for the signal return trampoline.  */
206 #define tramp mc_pad
207 
208 /* See arch/powerpc/kernel/signal.c.  */
209 static target_ulong get_sigframe(struct target_sigaction *ka,
210                                  CPUPPCState *env,
211                                  int frame_size)
212 {
213     target_ulong oldsp;
214 
215     oldsp = target_sigsp(get_sp_from_cpustate(env), ka);
216 
217     return (oldsp - frame_size) & ~0xFUL;
218 }
219 
220 #if ((defined(TARGET_WORDS_BIGENDIAN) && defined(HOST_WORDS_BIGENDIAN)) || \
221      (!defined(HOST_WORDS_BIGENDIAN) && !defined(TARGET_WORDS_BIGENDIAN)))
222 #define PPC_VEC_HI      0
223 #define PPC_VEC_LO      1
224 #else
225 #define PPC_VEC_HI      1
226 #define PPC_VEC_LO      0
227 #endif
228 
229 
230 static void save_user_regs(CPUPPCState *env, struct target_mcontext *frame)
231 {
232     target_ulong msr = env->msr;
233     int i;
234     target_ulong ccr = 0;
235 
236     /* In general, the kernel attempts to be intelligent about what it
237        needs to save for Altivec/FP/SPE registers.  We don't care that
238        much, so we just go ahead and save everything.  */
239 
240     /* Save general registers.  */
241     for (i = 0; i < ARRAY_SIZE(env->gpr); i++) {
242         __put_user(env->gpr[i], &frame->mc_gregs[i]);
243     }
244     __put_user(env->nip, &frame->mc_gregs[TARGET_PT_NIP]);
245     __put_user(env->ctr, &frame->mc_gregs[TARGET_PT_CTR]);
246     __put_user(env->lr, &frame->mc_gregs[TARGET_PT_LNK]);
247     __put_user(env->xer, &frame->mc_gregs[TARGET_PT_XER]);
248 
249     for (i = 0; i < ARRAY_SIZE(env->crf); i++) {
250         ccr |= env->crf[i] << (32 - ((i + 1) * 4));
251     }
252     __put_user(ccr, &frame->mc_gregs[TARGET_PT_CCR]);
253 
254     /* Save Altivec registers if necessary.  */
255     if (env->insns_flags & PPC_ALTIVEC) {
256         uint32_t *vrsave;
257         for (i = 0; i < 32; i++) {
258             ppc_avr_t *avr = cpu_avr_ptr(env, i);
259             ppc_avr_t *vreg = (ppc_avr_t *)&frame->mc_vregs.altivec[i];
260 
261             __put_user(avr->u64[PPC_VEC_HI], &vreg->u64[0]);
262             __put_user(avr->u64[PPC_VEC_LO], &vreg->u64[1]);
263         }
264         /* Set MSR_VR in the saved MSR value to indicate that
265            frame->mc_vregs contains valid data.  */
266         msr |= MSR_VR;
267 #if defined(TARGET_PPC64)
268         vrsave = (uint32_t *)&frame->mc_vregs.altivec[33];
269         /* 64-bit needs to put a pointer to the vectors in the frame */
270         __put_user(h2g(frame->mc_vregs.altivec), &frame->v_regs);
271 #else
272         vrsave = (uint32_t *)&frame->mc_vregs.altivec[32];
273 #endif
274         __put_user((uint32_t)env->spr[SPR_VRSAVE], vrsave);
275     }
276 
277 #if defined(TARGET_PPC64)
278     /* Save VSX second halves */
279     if (env->insns_flags2 & PPC2_VSX) {
280         uint64_t *vsregs = (uint64_t *)&frame->mc_vregs.altivec[34];
281         for (i = 0; i < 32; i++) {
282             uint64_t *vsrl = cpu_vsrl_ptr(env, i);
283             __put_user(*vsrl, &vsregs[i]);
284         }
285     }
286 #endif
287 
288     /* Save floating point registers.  */
289     if (env->insns_flags & PPC_FLOAT) {
290         for (i = 0; i < 32; i++) {
291             uint64_t *fpr = cpu_fpr_ptr(env, i);
292             __put_user(*fpr, &frame->mc_fregs[i]);
293         }
294         __put_user((uint64_t) env->fpscr, &frame->mc_fregs[32]);
295     }
296 
297 #if !defined(TARGET_PPC64)
298     /* Save SPE registers.  The kernel only saves the high half.  */
299     if (env->insns_flags & PPC_SPE) {
300         for (i = 0; i < ARRAY_SIZE(env->gprh); i++) {
301             __put_user(env->gprh[i], &frame->mc_vregs.spe[i]);
302         }
303         /* Set MSR_SPE in the saved MSR value to indicate that
304            frame->mc_vregs contains valid data.  */
305         msr |= MSR_SPE;
306         __put_user(env->spe_fscr, &frame->mc_vregs.spe[32]);
307     }
308 #endif
309 
310     /* Store MSR.  */
311     __put_user(msr, &frame->mc_gregs[TARGET_PT_MSR]);
312 }
313 
314 static void encode_trampoline(int sigret, uint32_t *tramp)
315 {
316     /* Set up the sigreturn trampoline: li r0,sigret; sc.  */
317     if (sigret) {
318         __put_user(0x38000000 | sigret, &tramp[0]);
319         __put_user(0x44000002, &tramp[1]);
320     }
321 }
322 
323 static void restore_user_regs(CPUPPCState *env,
324                               struct target_mcontext *frame, int sig)
325 {
326     target_ulong save_r2 = 0;
327     target_ulong msr;
328     target_ulong ccr;
329 
330     int i;
331 
332     if (!sig) {
333         save_r2 = env->gpr[2];
334     }
335 
336     /* Restore general registers.  */
337     for (i = 0; i < ARRAY_SIZE(env->gpr); i++) {
338         __get_user(env->gpr[i], &frame->mc_gregs[i]);
339     }
340     __get_user(env->nip, &frame->mc_gregs[TARGET_PT_NIP]);
341     __get_user(env->ctr, &frame->mc_gregs[TARGET_PT_CTR]);
342     __get_user(env->lr, &frame->mc_gregs[TARGET_PT_LNK]);
343     __get_user(env->xer, &frame->mc_gregs[TARGET_PT_XER]);
344     __get_user(ccr, &frame->mc_gregs[TARGET_PT_CCR]);
345 
346     for (i = 0; i < ARRAY_SIZE(env->crf); i++) {
347         env->crf[i] = (ccr >> (32 - ((i + 1) * 4))) & 0xf;
348     }
349 
350     if (!sig) {
351         env->gpr[2] = save_r2;
352     }
353     /* Restore MSR.  */
354     __get_user(msr, &frame->mc_gregs[TARGET_PT_MSR]);
355 
356     /* If doing signal return, restore the previous little-endian mode.  */
357     if (sig)
358         env->msr = (env->msr & ~(1ull << MSR_LE)) | (msr & (1ull << MSR_LE));
359 
360     /* Restore Altivec registers if necessary.  */
361     if (env->insns_flags & PPC_ALTIVEC) {
362         ppc_avr_t *v_regs;
363         uint32_t *vrsave;
364 #if defined(TARGET_PPC64)
365         uint64_t v_addr;
366         /* 64-bit needs to recover the pointer to the vectors from the frame */
367         __get_user(v_addr, &frame->v_regs);
368         v_regs = g2h(env_cpu(env), v_addr);
369 #else
370         v_regs = (ppc_avr_t *)frame->mc_vregs.altivec;
371 #endif
372         for (i = 0; i < 32; i++) {
373             ppc_avr_t *avr = cpu_avr_ptr(env, i);
374             ppc_avr_t *vreg = &v_regs[i];
375 
376             __get_user(avr->u64[PPC_VEC_HI], &vreg->u64[0]);
377             __get_user(avr->u64[PPC_VEC_LO], &vreg->u64[1]);
378         }
379         /* Set MSR_VEC in the saved MSR value to indicate that
380            frame->mc_vregs contains valid data.  */
381 #if defined(TARGET_PPC64)
382         vrsave = (uint32_t *)&v_regs[33];
383 #else
384         vrsave = (uint32_t *)&v_regs[32];
385 #endif
386         __get_user(env->spr[SPR_VRSAVE], vrsave);
387     }
388 
389 #if defined(TARGET_PPC64)
390     /* Restore VSX second halves */
391     if (env->insns_flags2 & PPC2_VSX) {
392         uint64_t *vsregs = (uint64_t *)&frame->mc_vregs.altivec[34];
393         for (i = 0; i < 32; i++) {
394             uint64_t *vsrl = cpu_vsrl_ptr(env, i);
395             __get_user(*vsrl, &vsregs[i]);
396         }
397     }
398 #endif
399 
400     /* Restore floating point registers.  */
401     if (env->insns_flags & PPC_FLOAT) {
402         uint64_t fpscr;
403         for (i = 0; i < 32; i++) {
404             uint64_t *fpr = cpu_fpr_ptr(env, i);
405             __get_user(*fpr, &frame->mc_fregs[i]);
406         }
407         __get_user(fpscr, &frame->mc_fregs[32]);
408         env->fpscr = (uint32_t) fpscr;
409     }
410 
411 #if !defined(TARGET_PPC64)
412     /* Save SPE registers.  The kernel only saves the high half.  */
413     if (env->insns_flags & PPC_SPE) {
414         for (i = 0; i < ARRAY_SIZE(env->gprh); i++) {
415             __get_user(env->gprh[i], &frame->mc_vregs.spe[i]);
416         }
417         __get_user(env->spe_fscr, &frame->mc_vregs.spe[32]);
418     }
419 #endif
420 }
421 
422 #if !defined(TARGET_PPC64)
423 void setup_frame(int sig, struct target_sigaction *ka,
424                  target_sigset_t *set, CPUPPCState *env)
425 {
426     struct target_sigframe *frame;
427     struct target_sigcontext *sc;
428     target_ulong frame_addr, newsp;
429     int err = 0;
430 
431     frame_addr = get_sigframe(ka, env, sizeof(*frame));
432     trace_user_setup_frame(env, frame_addr);
433     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 1))
434         goto sigsegv;
435     sc = &frame->sctx;
436 
437     __put_user(ka->_sa_handler, &sc->handler);
438     __put_user(set->sig[0], &sc->oldmask);
439     __put_user(set->sig[1], &sc->_unused[3]);
440     __put_user(h2g(&frame->mctx), &sc->regs);
441     __put_user(sig, &sc->signal);
442 
443     /* Save user regs.  */
444     save_user_regs(env, &frame->mctx);
445 
446     /* Construct the trampoline code on the stack. */
447     encode_trampoline(TARGET_NR_sigreturn, (uint32_t *)&frame->mctx.tramp);
448 
449     /* The kernel checks for the presence of a VDSO here.  We don't
450        emulate a vdso, so use a sigreturn system call.  */
451     env->lr = (target_ulong) h2g(frame->mctx.tramp);
452 
453     /* Turn off all fp exceptions.  */
454     env->fpscr = 0;
455 
456     /* Create a stack frame for the caller of the handler.  */
457     newsp = frame_addr - SIGNAL_FRAMESIZE;
458     err |= put_user(env->gpr[1], newsp, target_ulong);
459 
460     if (err)
461         goto sigsegv;
462 
463     /* Set up registers for signal handler.  */
464     env->gpr[1] = newsp;
465     env->gpr[3] = sig;
466     env->gpr[4] = frame_addr + offsetof(struct target_sigframe, sctx);
467 
468     env->nip = (target_ulong) ka->_sa_handler;
469 
470     /* Signal handlers are entered in big-endian mode.  */
471     env->msr &= ~(1ull << MSR_LE);
472 
473     unlock_user_struct(frame, frame_addr, 1);
474     return;
475 
476 sigsegv:
477     unlock_user_struct(frame, frame_addr, 1);
478     force_sigsegv(sig);
479 }
480 #endif /* !defined(TARGET_PPC64) */
481 
482 void setup_rt_frame(int sig, struct target_sigaction *ka,
483                     target_siginfo_t *info,
484                     target_sigset_t *set, CPUPPCState *env)
485 {
486     struct target_rt_sigframe *rt_sf;
487     uint32_t *trampptr = 0;
488     struct target_mcontext *mctx = 0;
489     target_ulong rt_sf_addr, newsp = 0;
490     int i, err = 0;
491 #if defined(TARGET_PPC64)
492     struct target_sigcontext *sc = 0;
493 #if !defined(TARGET_ABI32)
494     struct image_info *image = ((TaskState *)thread_cpu->opaque)->info;
495 #endif
496 #endif
497 
498     rt_sf_addr = get_sigframe(ka, env, sizeof(*rt_sf));
499     if (!lock_user_struct(VERIFY_WRITE, rt_sf, rt_sf_addr, 1))
500         goto sigsegv;
501 
502     tswap_siginfo(&rt_sf->info, info);
503 
504     __put_user(0, &rt_sf->uc.tuc_flags);
505     __put_user(0, &rt_sf->uc.tuc_link);
506     target_save_altstack(&rt_sf->uc.tuc_stack, env);
507 #if !defined(TARGET_PPC64)
508     __put_user(h2g (&rt_sf->uc.tuc_mcontext),
509                &rt_sf->uc.tuc_regs);
510 #endif
511     for(i = 0; i < TARGET_NSIG_WORDS; i++) {
512         __put_user(set->sig[i], &rt_sf->uc.tuc_sigmask.sig[i]);
513     }
514 
515 #if defined(TARGET_PPC64)
516     mctx = &rt_sf->uc.tuc_sigcontext.mcontext;
517     trampptr = &rt_sf->trampoline[0];
518 
519     sc = &rt_sf->uc.tuc_sigcontext;
520     __put_user(h2g(mctx), &sc->regs);
521     __put_user(sig, &sc->signal);
522 #else
523     mctx = &rt_sf->uc.tuc_mcontext;
524     trampptr = (uint32_t *)&rt_sf->uc.tuc_mcontext.tramp;
525 #endif
526 
527     save_user_regs(env, mctx);
528     encode_trampoline(TARGET_NR_rt_sigreturn, trampptr);
529 
530     /* The kernel checks for the presence of a VDSO here.  We don't
531        emulate a vdso, so use a sigreturn system call.  */
532     env->lr = (target_ulong) h2g(trampptr);
533 
534     /* Turn off all fp exceptions.  */
535     env->fpscr = 0;
536 
537     /* Create a stack frame for the caller of the handler.  */
538     newsp = rt_sf_addr - (SIGNAL_FRAMESIZE + 16);
539     err |= put_user(env->gpr[1], newsp, target_ulong);
540 
541     if (err)
542         goto sigsegv;
543 
544     /* Set up registers for signal handler.  */
545     env->gpr[1] = newsp;
546     env->gpr[3] = (target_ulong) sig;
547     env->gpr[4] = (target_ulong) h2g(&rt_sf->info);
548     env->gpr[5] = (target_ulong) h2g(&rt_sf->uc);
549     env->gpr[6] = (target_ulong) h2g(rt_sf);
550 
551 #if defined(TARGET_PPC64) && !defined(TARGET_ABI32)
552     if (get_ppc64_abi(image) < 2) {
553         /* ELFv1 PPC64 function pointers are pointers to OPD entries. */
554         struct target_func_ptr *handler =
555             (struct target_func_ptr *)g2h(env_cpu(env), ka->_sa_handler);
556         env->nip = tswapl(handler->entry);
557         env->gpr[2] = tswapl(handler->toc);
558     } else {
559         /* ELFv2 PPC64 function pointers are entry points. R12 must also be set. */
560         env->gpr[12] = env->nip = ka->_sa_handler;
561     }
562 #else
563     env->nip = (target_ulong) ka->_sa_handler;
564 #endif
565 
566     /* Signal handlers are entered in big-endian mode.  */
567     env->msr &= ~(1ull << MSR_LE);
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     do_sigaltstack(rt_sf_addr
660                    + offsetof(struct target_rt_sigframe, uc.tuc_stack),
661                    0, env->gpr[1]);
662 
663     unlock_user_struct(rt_sf, rt_sf_addr, 1);
664     return -TARGET_QEMU_ESIGRETURN;
665 
666 sigsegv:
667     unlock_user_struct(rt_sf, rt_sf_addr, 1);
668     force_sig(TARGET_SIGSEGV);
669     return -TARGET_QEMU_ESIGRETURN;
670 }
671 
672 /* This syscall implements {get,set,swap}context for userland.  */
673 abi_long do_swapcontext(CPUArchState *env, abi_ulong uold_ctx,
674                         abi_ulong unew_ctx, abi_long ctx_size)
675 {
676     struct target_ucontext *uctx;
677     struct target_mcontext *mctx;
678 
679     /* For ppc32, ctx_size is "reserved for future use".
680      * For ppc64, we do not yet support the VSX extension.
681      */
682     if (ctx_size < sizeof(struct target_ucontext)) {
683         return -TARGET_EINVAL;
684     }
685 
686     if (uold_ctx) {
687         TaskState *ts = (TaskState *)thread_cpu->opaque;
688 
689         if (!lock_user_struct(VERIFY_WRITE, uctx, uold_ctx, 1)) {
690             return -TARGET_EFAULT;
691         }
692 
693 #ifdef TARGET_PPC64
694         mctx = &uctx->tuc_sigcontext.mcontext;
695 #else
696         /* ??? The kernel aligns the pointer down here into padding, but
697          * in setup_rt_frame we don't.  Be self-compatible for now.
698          */
699         mctx = &uctx->tuc_mcontext;
700         __put_user(h2g(mctx), &uctx->tuc_regs);
701 #endif
702 
703         save_user_regs(env, mctx);
704         host_to_target_sigset(&uctx->tuc_sigmask, &ts->signal_mask);
705 
706         unlock_user_struct(uctx, uold_ctx, 1);
707     }
708 
709     if (unew_ctx) {
710         int err;
711 
712         if (!lock_user_struct(VERIFY_READ, uctx, unew_ctx, 1)) {
713             return -TARGET_EFAULT;
714         }
715         err = do_setcontext(uctx, env, 0);
716         unlock_user_struct(uctx, unew_ctx, 1);
717 
718         if (err) {
719             /* We cannot return to a partially updated context.  */
720             force_sig(TARGET_SIGSEGV);
721         }
722         return -TARGET_QEMU_ESIGRETURN;
723     }
724 
725     return 0;
726 }
727