xref: /qemu/linux-user/i386/signal.c (revision 9e9b7d4c15b1cbefc608487a38e10c8f708fb187)
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 "user/tswap-target.h"
25 
26 /* from the Linux kernel - /arch/x86/include/uapi/asm/sigcontext.h */
27 
28 #define TARGET_FP_XSTATE_MAGIC1         0x46505853U /* FPXS */
29 #define TARGET_FP_XSTATE_MAGIC2         0x46505845U /* FPXE */
30 #define TARGET_FP_XSTATE_MAGIC2_SIZE    4
31 
32 struct target_fpreg {
33     uint16_t significand[4];
34     uint16_t exponent;
35 };
36 
37 /* Legacy x87 fpu state format for FSAVE/FRESTOR. */
38 struct target_fregs_state {
39     uint32_t cwd;
40     uint32_t swd;
41     uint32_t twd;
42     uint32_t fip;
43     uint32_t fcs;
44     uint32_t foo;
45     uint32_t fos;
46     struct target_fpreg st[8];
47 
48     /* Software status information [not touched by FSAVE]. */
49     uint16_t status;
50     uint16_t magic;   /* 0xffff: FPU data only, 0x0000: FXSR FPU data */
51 };
52 QEMU_BUILD_BUG_ON(sizeof(struct target_fregs_state) != 32 + 80);
53 
54 struct target_fpx_sw_bytes {
55     uint32_t magic1;
56     uint32_t extended_size;
57     uint64_t xfeatures;
58     uint32_t xstate_size;
59     uint32_t reserved[7];
60 };
61 QEMU_BUILD_BUG_ON(sizeof(struct target_fpx_sw_bytes) != 12*4);
62 
63 struct target_fpstate_32 {
64     struct target_fregs_state fpstate;
65     X86LegacyXSaveArea fxstate;
66 };
67 
68 /*
69  * For simplicity, setup_frame aligns struct target_fpstate_32 to
70  * 16 bytes, so ensure that the FXSAVE area is also aligned.
71  */
72 QEMU_BUILD_BUG_ON(offsetof(struct target_fpstate_32, fxstate) & 15);
73 
74 #ifndef TARGET_X86_64
75 # define target_fpstate target_fpstate_32
76 # define TARGET_FPSTATE_FXSAVE_OFFSET offsetof(struct target_fpstate_32, fxstate)
77 #else
78 # define target_fpstate X86LegacyXSaveArea
79 # define TARGET_FPSTATE_FXSAVE_OFFSET 0
80 #endif
81 
82 struct target_sigcontext_32 {
83     uint16_t gs, __gsh;
84     uint16_t fs, __fsh;
85     uint16_t es, __esh;
86     uint16_t ds, __dsh;
87     uint32_t edi;
88     uint32_t esi;
89     uint32_t ebp;
90     uint32_t esp;
91     uint32_t ebx;
92     uint32_t edx;
93     uint32_t ecx;
94     uint32_t eax;
95     uint32_t trapno;
96     uint32_t err;
97     uint32_t eip;
98     uint16_t cs, __csh;
99     uint32_t eflags;
100     uint32_t esp_at_signal;
101     uint16_t ss, __ssh;
102     uint32_t fpstate; /* pointer */
103     uint32_t oldmask;
104     uint32_t cr2;
105 };
106 
107 struct target_sigcontext_64 {
108     uint64_t r8;
109     uint64_t r9;
110     uint64_t r10;
111     uint64_t r11;
112     uint64_t r12;
113     uint64_t r13;
114     uint64_t r14;
115     uint64_t r15;
116 
117     uint64_t rdi;
118     uint64_t rsi;
119     uint64_t rbp;
120     uint64_t rbx;
121     uint64_t rdx;
122     uint64_t rax;
123     uint64_t rcx;
124     uint64_t rsp;
125     uint64_t rip;
126 
127     uint64_t eflags;
128 
129     uint16_t cs;
130     uint16_t gs;
131     uint16_t fs;
132     uint16_t ss;
133 
134     uint64_t err;
135     uint64_t trapno;
136     uint64_t oldmask;
137     uint64_t cr2;
138 
139     uint64_t fpstate; /* pointer */
140     uint64_t padding[8];
141 };
142 
143 #ifndef TARGET_X86_64
144 # define target_sigcontext target_sigcontext_32
145 #else
146 # define target_sigcontext target_sigcontext_64
147 #endif
148 
149 /* see Linux/include/uapi/asm-generic/ucontext.h */
150 struct target_ucontext {
151     abi_ulong         tuc_flags;
152     abi_ulong         tuc_link;
153     target_stack_t    tuc_stack;
154     struct target_sigcontext tuc_mcontext;
155     target_sigset_t   tuc_sigmask;  /* mask last for extensibility */
156 };
157 
158 #ifndef TARGET_X86_64
159 struct sigframe {
160     abi_ulong pretcode;
161     int sig;
162     struct target_sigcontext sc;
163     /*
164      * The actual fpstate is placed after retcode[] below, to make
165      * room for the variable-sized xsave data.  The older unused fpstate
166      * has to be kept to avoid changing the offset of extramask[], which
167      * is part of the ABI.
168      */
169     struct target_fpstate fpstate_unused;
170     abi_ulong extramask[TARGET_NSIG_WORDS-1];
171     char retcode[8];
172 
173     /*
174      * This field will be 16-byte aligned in memory.  Applying QEMU_ALIGNED
175      * to it ensures that the base of the frame has an appropriate alignment
176      * too.
177      */
178     struct target_fpstate fpstate QEMU_ALIGNED(8);
179 };
180 #define TARGET_SIGFRAME_FXSAVE_OFFSET (                                    \
181     offsetof(struct sigframe, fpstate) + TARGET_FPSTATE_FXSAVE_OFFSET)
182 
183 struct rt_sigframe {
184     abi_ulong pretcode;
185     int sig;
186     abi_ulong pinfo;
187     abi_ulong puc;
188     struct target_siginfo info;
189     struct target_ucontext uc;
190     char retcode[8];
191     struct target_fpstate fpstate QEMU_ALIGNED(8);
192 };
193 #define TARGET_RT_SIGFRAME_FXSAVE_OFFSET (                                 \
194     offsetof(struct rt_sigframe, fpstate) + TARGET_FPSTATE_FXSAVE_OFFSET)
195 
196 /*
197  * Verify that vdso-asmoffset.h constants match.
198  */
199 #include "i386/vdso-asmoffset.h"
200 
201 QEMU_BUILD_BUG_ON(offsetof(struct sigframe, sc.eip)
202                   != SIGFRAME_SIGCONTEXT_eip);
203 QEMU_BUILD_BUG_ON(offsetof(struct rt_sigframe, uc.tuc_mcontext.eip)
204                   != RT_SIGFRAME_SIGCONTEXT_eip);
205 
206 #else
207 
208 struct rt_sigframe {
209     abi_ulong pretcode;
210     struct target_ucontext uc;
211     struct target_siginfo info;
212     struct target_fpstate fpstate QEMU_ALIGNED(16);
213 };
214 #define TARGET_RT_SIGFRAME_FXSAVE_OFFSET (                                 \
215     offsetof(struct rt_sigframe, fpstate) + TARGET_FPSTATE_FXSAVE_OFFSET)
216 #endif
217 
218 /*
219  * Set up a signal frame.
220  */
221 
222 static void xsave_sigcontext(CPUX86State *env, X86LegacyXSaveArea *fxsave,
223                              abi_ulong fxsave_addr)
224 {
225     struct target_fpx_sw_bytes *sw = (void *)&fxsave->sw_reserved;
226 
227     if (!(env->features[FEAT_1_ECX] & CPUID_EXT_XSAVE)) {
228         /* fxsave_addr must be 16 byte aligned for fxsave */
229         assert(!(fxsave_addr & 0xf));
230 
231         cpu_x86_fxsave(env, fxsave_addr);
232         __put_user(0, &sw->magic1);
233     } else {
234         uint32_t xstate_size = xsave_area_size(env->xcr0, false);
235 
236         /*
237          * extended_size is the offset from fpstate_addr to right after the end
238          * of the extended save states.  On 32-bit that includes the legacy
239          * FSAVE area.
240          */
241         uint32_t extended_size = TARGET_FPSTATE_FXSAVE_OFFSET
242             + xstate_size + TARGET_FP_XSTATE_MAGIC2_SIZE;
243 
244         /* fxsave_addr must be 64 byte aligned for xsave */
245         assert(!(fxsave_addr & 0x3f));
246 
247         /* Zero the header, XSAVE *adds* features to an existing save state.  */
248         memset(fxsave + 1, 0, sizeof(X86XSaveHeader));
249         cpu_x86_xsave(env, fxsave_addr, -1);
250         __put_user(TARGET_FP_XSTATE_MAGIC1, &sw->magic1);
251         __put_user(extended_size, &sw->extended_size);
252         __put_user(env->xcr0, &sw->xfeatures);
253         __put_user(xstate_size, &sw->xstate_size);
254         __put_user(TARGET_FP_XSTATE_MAGIC2,
255                    (uint32_t *)((void *)fxsave + xstate_size));
256     }
257 }
258 
259 static void setup_sigcontext(struct target_sigcontext *sc,
260         struct target_fpstate *fpstate, CPUX86State *env, abi_ulong mask,
261         abi_ulong fpstate_addr)
262 {
263     CPUState *cs = env_cpu(env);
264 #ifndef TARGET_X86_64
265     uint16_t magic;
266 
267     /* already locked in setup_frame() */
268     __put_user(env->segs[R_GS].selector, (unsigned int *)&sc->gs);
269     __put_user(env->segs[R_FS].selector, (unsigned int *)&sc->fs);
270     __put_user(env->segs[R_ES].selector, (unsigned int *)&sc->es);
271     __put_user(env->segs[R_DS].selector, (unsigned int *)&sc->ds);
272     __put_user(env->regs[R_EDI], &sc->edi);
273     __put_user(env->regs[R_ESI], &sc->esi);
274     __put_user(env->regs[R_EBP], &sc->ebp);
275     __put_user(env->regs[R_ESP], &sc->esp);
276     __put_user(env->regs[R_EBX], &sc->ebx);
277     __put_user(env->regs[R_EDX], &sc->edx);
278     __put_user(env->regs[R_ECX], &sc->ecx);
279     __put_user(env->regs[R_EAX], &sc->eax);
280     __put_user(cs->exception_index, &sc->trapno);
281     __put_user(env->error_code, &sc->err);
282     __put_user(env->eip, &sc->eip);
283     __put_user(env->segs[R_CS].selector, (unsigned int *)&sc->cs);
284     __put_user(env->eflags, &sc->eflags);
285     __put_user(env->regs[R_ESP], &sc->esp_at_signal);
286     __put_user(env->segs[R_SS].selector, (unsigned int *)&sc->ss);
287 
288     cpu_x86_fsave(env, fpstate_addr, 1);
289     fpstate->fpstate.status = fpstate->fpstate.swd;
290     if (!(env->features[FEAT_1_EDX] & CPUID_FXSR)) {
291         magic = 0xffff;
292     } else {
293         xsave_sigcontext(env, &fpstate->fxstate,
294                          fpstate_addr + TARGET_FPSTATE_FXSAVE_OFFSET);
295         magic = 0;
296     }
297     __put_user(magic, &fpstate->fpstate.magic);
298 #else
299     __put_user(env->regs[R_EDI], &sc->rdi);
300     __put_user(env->regs[R_ESI], &sc->rsi);
301     __put_user(env->regs[R_EBP], &sc->rbp);
302     __put_user(env->regs[R_ESP], &sc->rsp);
303     __put_user(env->regs[R_EBX], &sc->rbx);
304     __put_user(env->regs[R_EDX], &sc->rdx);
305     __put_user(env->regs[R_ECX], &sc->rcx);
306     __put_user(env->regs[R_EAX], &sc->rax);
307 
308     __put_user(env->regs[8], &sc->r8);
309     __put_user(env->regs[9], &sc->r9);
310     __put_user(env->regs[10], &sc->r10);
311     __put_user(env->regs[11], &sc->r11);
312     __put_user(env->regs[12], &sc->r12);
313     __put_user(env->regs[13], &sc->r13);
314     __put_user(env->regs[14], &sc->r14);
315     __put_user(env->regs[15], &sc->r15);
316 
317     __put_user(cs->exception_index, &sc->trapno);
318     __put_user(env->error_code, &sc->err);
319     __put_user(env->eip, &sc->rip);
320 
321     __put_user(env->eflags, &sc->eflags);
322     __put_user(env->segs[R_CS].selector, &sc->cs);
323     __put_user((uint16_t)0, &sc->gs);
324     __put_user((uint16_t)0, &sc->fs);
325     __put_user(env->segs[R_SS].selector, &sc->ss);
326 
327     xsave_sigcontext(env, fpstate, fpstate_addr);
328 #endif
329 
330     __put_user(fpstate_addr, &sc->fpstate);
331 
332     /* non-iBCS2 extensions.. */
333     __put_user(mask, &sc->oldmask);
334     __put_user(env->cr[2], &sc->cr2);
335 }
336 
337 /*
338  * Determine which stack to use..
339  */
340 
341 static inline abi_ulong
342 get_sigframe(struct target_sigaction *ka, CPUX86State *env, size_t fxsave_offset)
343 {
344     unsigned long esp;
345 
346     /* Default to using normal stack */
347     esp = get_sp_from_cpustate(env);
348 #ifdef TARGET_X86_64
349     esp -= 128; /* this is the redzone */
350 #endif
351 
352     /* This is the X/Open sanctioned signal stack switching.  */
353     if (ka->sa_flags & TARGET_SA_ONSTACK) {
354         esp = target_sigsp(esp, ka);
355     } else {
356 #ifndef TARGET_X86_64
357         /* This is the legacy signal stack switching. */
358         if ((env->segs[R_SS].selector & 0xffff) != __USER_DS &&
359                 !(ka->sa_flags & TARGET_SA_RESTORER) &&
360                 ka->sa_restorer) {
361             esp = (unsigned long) ka->sa_restorer;
362         }
363 #endif
364     }
365 
366     if (!(env->features[FEAT_1_EDX] & CPUID_FXSR)) {
367         return (esp - (fxsave_offset + sizeof(X86LegacyXSaveArea))) & -8ul;
368     } else if (!(env->features[FEAT_1_ECX] & CPUID_EXT_XSAVE)) {
369         return ((esp - sizeof(X86LegacyXSaveArea)) & -16ul) - fxsave_offset;
370     } else {
371         size_t xstate_size =
372                xsave_area_size(env->xcr0, false) + TARGET_FP_XSTATE_MAGIC2_SIZE;
373         return ((esp - xstate_size) & -64ul) - fxsave_offset;
374     }
375 }
376 
377 #ifndef TARGET_X86_64
378 static void install_sigtramp(void *tramp)
379 {
380     /* This is popl %eax ; movl $syscall,%eax ; int $0x80 */
381     __put_user(0xb858, (uint16_t *)(tramp + 0));
382     __put_user(TARGET_NR_sigreturn, (int32_t *)(tramp + 2));
383     __put_user(0x80cd, (uint16_t *)(tramp + 6));
384 }
385 
386 static void install_rt_sigtramp(void *tramp)
387 {
388     /* This is movl $syscall,%eax ; int $0x80 */
389     __put_user(0xb8, (uint8_t *)(tramp + 0));
390     __put_user(TARGET_NR_rt_sigreturn, (int32_t *)(tramp + 1));
391     __put_user(0x80cd, (uint16_t *)(tramp + 5));
392 }
393 
394 /* compare linux/arch/i386/kernel/signal.c:setup_frame() */
395 void setup_frame(int sig, struct target_sigaction *ka,
396                  target_sigset_t *set, CPUX86State *env)
397 {
398     abi_ulong frame_addr;
399     struct sigframe *frame;
400     int i;
401 
402     frame_addr = get_sigframe(ka, env, TARGET_SIGFRAME_FXSAVE_OFFSET);
403     trace_user_setup_frame(env, frame_addr);
404 
405     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0))
406         goto give_sigsegv;
407 
408     setup_sigcontext(&frame->sc, &frame->fpstate, env, set->sig[0],
409             frame_addr + offsetof(struct sigframe, fpstate));
410 
411     for (i = 1; i < TARGET_NSIG_WORDS; i++) {
412         __put_user(set->sig[i], &frame->extramask[i - 1]);
413     }
414 
415     /* Set up to return from userspace.  If provided, use a stub
416        already in userspace.  */
417     if (ka->sa_flags & TARGET_SA_RESTORER) {
418         __put_user(ka->sa_restorer, &frame->pretcode);
419     } else {
420         /* This is no longer used, but is retained for ABI compatibility. */
421         install_sigtramp(frame->retcode);
422         __put_user(default_sigreturn, &frame->pretcode);
423     }
424 
425     /* Set up registers for signal handler */
426     env->regs[R_ESP] = frame_addr;
427     env->eip = ka->_sa_handler;
428 
429     /* Store argument for both -mregparm=3 and standard. */
430     env->regs[R_EAX] = sig;
431     __put_user(sig, &frame->sig);
432     /* The kernel clears EDX and ECX even though there is only one arg. */
433     env->regs[R_EDX] = 0;
434     env->regs[R_ECX] = 0;
435 
436     cpu_x86_load_seg(env, R_DS, __USER_DS);
437     cpu_x86_load_seg(env, R_ES, __USER_DS);
438     cpu_x86_load_seg(env, R_SS, __USER_DS);
439     cpu_x86_load_seg(env, R_CS, __USER_CS);
440     env->eflags &= ~TF_MASK;
441 
442     unlock_user_struct(frame, frame_addr, 1);
443 
444     return;
445 
446 give_sigsegv:
447     force_sigsegv(sig);
448 }
449 #endif
450 
451 /* compare linux/arch/x86/kernel/signal.c:setup_rt_frame() */
452 void setup_rt_frame(int sig, struct target_sigaction *ka,
453                     target_siginfo_t *info,
454                     target_sigset_t *set, CPUX86State *env)
455 {
456     abi_ulong frame_addr;
457     struct rt_sigframe *frame;
458     int i;
459 
460     frame_addr = get_sigframe(ka, env, TARGET_RT_SIGFRAME_FXSAVE_OFFSET);
461     trace_user_setup_rt_frame(env, frame_addr);
462 
463     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0))
464         goto give_sigsegv;
465 
466     if (ka->sa_flags & TARGET_SA_SIGINFO) {
467         frame->info = *info;
468     }
469 
470     /* Create the ucontext.  */
471     if (env->features[FEAT_1_ECX] & CPUID_EXT_XSAVE) {
472         __put_user(1, &frame->uc.tuc_flags);
473     } else {
474         __put_user(0, &frame->uc.tuc_flags);
475     }
476     __put_user(0, &frame->uc.tuc_link);
477     target_save_altstack(&frame->uc.tuc_stack, env);
478     setup_sigcontext(&frame->uc.tuc_mcontext, &frame->fpstate, env,
479             set->sig[0], frame_addr + offsetof(struct rt_sigframe, fpstate));
480 
481     for (i = 0; i < TARGET_NSIG_WORDS; i++) {
482         __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
483     }
484 
485     /* Set up to return from userspace.  If provided, use a stub
486        already in userspace.  */
487     if (ka->sa_flags & TARGET_SA_RESTORER) {
488         __put_user(ka->sa_restorer, &frame->pretcode);
489     } else {
490 #ifdef TARGET_X86_64
491         /* For x86_64, SA_RESTORER is required ABI.  */
492         goto give_sigsegv;
493 #else
494         /* This is no longer used, but is retained for ABI compatibility. */
495         install_rt_sigtramp(frame->retcode);
496         __put_user(default_rt_sigreturn, &frame->pretcode);
497 #endif
498     }
499 
500     /* Set up registers for signal handler */
501     env->regs[R_ESP] = frame_addr;
502     env->eip = ka->_sa_handler;
503 
504 #ifndef TARGET_X86_64
505     /* Store arguments for both -mregparm=3 and standard. */
506     env->regs[R_EAX] = sig;
507     __put_user(sig, &frame->sig);
508     env->regs[R_EDX] = frame_addr + offsetof(struct rt_sigframe, info);
509     __put_user(env->regs[R_EDX], &frame->pinfo);
510     env->regs[R_ECX] = frame_addr + offsetof(struct rt_sigframe, uc);
511     __put_user(env->regs[R_ECX], &frame->puc);
512 #else
513     env->regs[R_EAX] = 0;
514     env->regs[R_EDI] = sig;
515     env->regs[R_ESI] = frame_addr + offsetof(struct rt_sigframe, info);
516     env->regs[R_EDX] = frame_addr + offsetof(struct rt_sigframe, uc);
517 #endif
518 
519     cpu_x86_load_seg(env, R_DS, __USER_DS);
520     cpu_x86_load_seg(env, R_ES, __USER_DS);
521     cpu_x86_load_seg(env, R_CS, __USER_CS);
522     cpu_x86_load_seg(env, R_SS, __USER_DS);
523     env->eflags &= ~TF_MASK;
524 
525     unlock_user_struct(frame, frame_addr, 1);
526 
527     return;
528 
529 give_sigsegv:
530     force_sigsegv(sig);
531 }
532 
533 static bool xrstor_sigcontext(CPUX86State *env, X86LegacyXSaveArea *fxsave,
534                               abi_ulong fxsave_addr)
535 {
536     struct target_fpx_sw_bytes *sw = (void *)&fxsave->sw_reserved;
537 
538     if (env->features[FEAT_1_ECX] & CPUID_EXT_XSAVE) {
539         uint32_t magic1 = tswapl(sw->magic1);
540         uint32_t extended_size = tswapl(sw->extended_size);
541         uint32_t xstate_size = tswapl(sw->xstate_size);
542         uint32_t minimum_size = (TARGET_FPSTATE_FXSAVE_OFFSET
543                                  + TARGET_FP_XSTATE_MAGIC2_SIZE
544                                  + xstate_size);
545         uint32_t magic2;
546 
547         /* Linux checks MAGIC2 using xstate_size, not extended_size.  */
548         if (magic1 == TARGET_FP_XSTATE_MAGIC1
549             && extended_size >= minimum_size) {
550             if (!access_ok(env_cpu(env), VERIFY_READ, fxsave_addr,
551                            extended_size - TARGET_FPSTATE_FXSAVE_OFFSET)) {
552                 return false;
553             }
554             magic2 = tswapl(*(uint32_t *)((void *)fxsave + xstate_size));
555             if (magic2 == TARGET_FP_XSTATE_MAGIC2) {
556                 cpu_x86_xrstor(env, fxsave_addr, -1);
557                 return true;
558             }
559         }
560         /* fall through to fxrstor */
561     }
562 
563     cpu_x86_fxrstor(env, fxsave_addr);
564     return true;
565 }
566 
567 static bool restore_sigcontext(CPUX86State *env, struct target_sigcontext *sc)
568 {
569     abi_ulong fpstate_addr;
570     unsigned int tmpflags;
571     struct target_fpstate *fpstate;
572     bool ok;
573 
574 #ifndef TARGET_X86_64
575     cpu_x86_load_seg(env, R_GS, tswap16(sc->gs));
576     cpu_x86_load_seg(env, R_FS, tswap16(sc->fs));
577     cpu_x86_load_seg(env, R_ES, tswap16(sc->es));
578     cpu_x86_load_seg(env, R_DS, tswap16(sc->ds));
579 
580     env->regs[R_EDI] = tswapl(sc->edi);
581     env->regs[R_ESI] = tswapl(sc->esi);
582     env->regs[R_EBP] = tswapl(sc->ebp);
583     env->regs[R_ESP] = tswapl(sc->esp);
584     env->regs[R_EBX] = tswapl(sc->ebx);
585     env->regs[R_EDX] = tswapl(sc->edx);
586     env->regs[R_ECX] = tswapl(sc->ecx);
587     env->regs[R_EAX] = tswapl(sc->eax);
588 
589     env->eip = tswapl(sc->eip);
590 #else
591     env->regs[8] = tswapl(sc->r8);
592     env->regs[9] = tswapl(sc->r9);
593     env->regs[10] = tswapl(sc->r10);
594     env->regs[11] = tswapl(sc->r11);
595     env->regs[12] = tswapl(sc->r12);
596     env->regs[13] = tswapl(sc->r13);
597     env->regs[14] = tswapl(sc->r14);
598     env->regs[15] = tswapl(sc->r15);
599 
600     env->regs[R_EDI] = tswapl(sc->rdi);
601     env->regs[R_ESI] = tswapl(sc->rsi);
602     env->regs[R_EBP] = tswapl(sc->rbp);
603     env->regs[R_EBX] = tswapl(sc->rbx);
604     env->regs[R_EDX] = tswapl(sc->rdx);
605     env->regs[R_EAX] = tswapl(sc->rax);
606     env->regs[R_ECX] = tswapl(sc->rcx);
607     env->regs[R_ESP] = tswapl(sc->rsp);
608 
609     env->eip = tswapl(sc->rip);
610 #endif
611 
612     cpu_x86_load_seg(env, R_CS, lduw_p(&sc->cs) | 3);
613     cpu_x86_load_seg(env, R_SS, lduw_p(&sc->ss) | 3);
614 
615     tmpflags = tswapl(sc->eflags);
616     env->eflags = (env->eflags & ~0x40DD5) | (tmpflags & 0x40DD5);
617     //          regs->orig_eax = -1;            /* disable syscall checks */
618 
619     fpstate_addr = tswapl(sc->fpstate);
620     if (fpstate_addr == 0) {
621         return true;
622     }
623     if (!lock_user_struct(VERIFY_READ, fpstate, fpstate_addr,
624                           sizeof(struct target_fpstate))) {
625         return false;
626     }
627 #ifndef TARGET_X86_64
628     if (!(env->features[FEAT_1_EDX] & CPUID_FXSR)) {
629         cpu_x86_frstor(env, fpstate_addr, 1);
630         ok = true;
631     } else {
632         ok = xrstor_sigcontext(env, &fpstate->fxstate,
633                                fpstate_addr + TARGET_FPSTATE_FXSAVE_OFFSET);
634     }
635 #else
636     ok = xrstor_sigcontext(env, fpstate, fpstate_addr);
637 #endif
638     unlock_user_struct(fpstate, fpstate_addr, 0);
639 
640     return ok;
641 }
642 
643 /* Note: there is no sigreturn on x86_64, there is only rt_sigreturn */
644 #ifndef TARGET_X86_64
645 long do_sigreturn(CPUX86State *env)
646 {
647     struct sigframe *frame;
648     abi_ulong frame_addr = env->regs[R_ESP] - 8;
649     target_sigset_t target_set;
650     sigset_t set;
651     int i;
652 
653     trace_user_do_sigreturn(env, frame_addr);
654     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))
655         goto badframe;
656     /* set blocked signals */
657     __get_user(target_set.sig[0], &frame->sc.oldmask);
658     for(i = 1; i < TARGET_NSIG_WORDS; i++) {
659         __get_user(target_set.sig[i], &frame->extramask[i - 1]);
660     }
661 
662     target_to_host_sigset_internal(&set, &target_set);
663     set_sigmask(&set);
664 
665     /* restore registers */
666     if (!restore_sigcontext(env, &frame->sc)) {
667         goto badframe;
668     }
669     unlock_user_struct(frame, frame_addr, 0);
670     return -QEMU_ESIGRETURN;
671 
672 badframe:
673     unlock_user_struct(frame, frame_addr, 0);
674     force_sig(TARGET_SIGSEGV);
675     return -QEMU_ESIGRETURN;
676 }
677 #endif
678 
679 long do_rt_sigreturn(CPUX86State *env)
680 {
681     abi_ulong frame_addr;
682     struct rt_sigframe *frame;
683     sigset_t set;
684 
685     frame_addr = env->regs[R_ESP] - sizeof(abi_ulong);
686     trace_user_do_rt_sigreturn(env, frame_addr);
687     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))
688         goto badframe;
689     target_to_host_sigset(&set, &frame->uc.tuc_sigmask);
690     set_sigmask(&set);
691 
692     if (!restore_sigcontext(env, &frame->uc.tuc_mcontext)) {
693         goto badframe;
694     }
695 
696     target_restore_altstack(&frame->uc.tuc_stack, env);
697 
698     unlock_user_struct(frame, frame_addr, 0);
699     return -QEMU_ESIGRETURN;
700 
701 badframe:
702     unlock_user_struct(frame, frame_addr, 0);
703     force_sig(TARGET_SIGSEGV);
704     return -QEMU_ESIGRETURN;
705 }
706 
707 #ifndef TARGET_X86_64
708 void setup_sigtramp(abi_ulong sigtramp_page)
709 {
710     uint16_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 2 * 8, 0);
711     assert(tramp != NULL);
712 
713     default_sigreturn = sigtramp_page;
714     install_sigtramp(tramp);
715 
716     default_rt_sigreturn = sigtramp_page + 8;
717     install_rt_sigtramp(tramp + 8);
718 
719     unlock_user(tramp, sigtramp_page, 2 * 8);
720 }
721 #endif
722