xref: /openbmc/qemu/linux-user/i386/signal.c (revision 4921d0a7)
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 struct target_fpxreg {
38     uint16_t significand[4];
39     uint16_t exponent;
40     uint16_t padding[3];
41 };
42 
43 struct target_xmmreg {
44     uint32_t element[4];
45 };
46 
47 struct target_fpx_sw_bytes {
48     uint32_t magic1;
49     uint32_t extended_size;
50     uint64_t xfeatures;
51     uint32_t xstate_size;
52     uint32_t reserved[7];
53 };
54 QEMU_BUILD_BUG_ON(sizeof(struct target_fpx_sw_bytes) != 12*4);
55 
56 struct target_fpstate_fxsave {
57     /* FXSAVE format */
58     uint16_t cw;
59     uint16_t sw;
60     uint16_t twd;
61     uint16_t fop;
62     uint64_t rip;
63     uint64_t rdp;
64     uint32_t mxcsr;
65     uint32_t mxcsr_mask;
66     uint32_t st_space[32];
67     uint32_t xmm_space[64];
68     uint32_t hw_reserved[12];
69     struct target_fpx_sw_bytes sw_reserved;
70     uint8_t xfeatures[];
71 };
72 #define TARGET_FXSAVE_SIZE   sizeof(struct target_fpstate_fxsave)
73 QEMU_BUILD_BUG_ON(TARGET_FXSAVE_SIZE != 512);
74 QEMU_BUILD_BUG_ON(offsetof(struct target_fpstate_fxsave, sw_reserved) != 464);
75 
76 struct target_fpstate_32 {
77     /* Regular FPU environment */
78     uint32_t cw;
79     uint32_t sw;
80     uint32_t tag;
81     uint32_t ipoff;
82     uint32_t cssel;
83     uint32_t dataoff;
84     uint32_t datasel;
85     struct target_fpreg st[8];
86     uint16_t  status;
87     uint16_t  magic;          /* 0xffff = regular FPU data only */
88     struct target_fpstate_fxsave fxsave;
89 };
90 
91 /*
92  * For simplicity, setup_frame aligns struct target_fpstate_32 to
93  * 16 bytes, so ensure that the FXSAVE area is also aligned.
94  */
95 QEMU_BUILD_BUG_ON(offsetof(struct target_fpstate_32, fxsave) & 15);
96 
97 #ifndef TARGET_X86_64
98 # define target_fpstate target_fpstate_32
99 # define TARGET_FPSTATE_FXSAVE_OFFSET offsetof(struct target_fpstate_32, fxsave)
100 #else
101 # define target_fpstate target_fpstate_fxsave
102 # define TARGET_FPSTATE_FXSAVE_OFFSET 0
103 #endif
104 
105 struct target_sigcontext_32 {
106     uint16_t gs, __gsh;
107     uint16_t fs, __fsh;
108     uint16_t es, __esh;
109     uint16_t ds, __dsh;
110     uint32_t edi;
111     uint32_t esi;
112     uint32_t ebp;
113     uint32_t esp;
114     uint32_t ebx;
115     uint32_t edx;
116     uint32_t ecx;
117     uint32_t eax;
118     uint32_t trapno;
119     uint32_t err;
120     uint32_t eip;
121     uint16_t cs, __csh;
122     uint32_t eflags;
123     uint32_t esp_at_signal;
124     uint16_t ss, __ssh;
125     uint32_t fpstate; /* pointer */
126     uint32_t oldmask;
127     uint32_t cr2;
128 };
129 
130 struct target_sigcontext_64 {
131     uint64_t r8;
132     uint64_t r9;
133     uint64_t r10;
134     uint64_t r11;
135     uint64_t r12;
136     uint64_t r13;
137     uint64_t r14;
138     uint64_t r15;
139 
140     uint64_t rdi;
141     uint64_t rsi;
142     uint64_t rbp;
143     uint64_t rbx;
144     uint64_t rdx;
145     uint64_t rax;
146     uint64_t rcx;
147     uint64_t rsp;
148     uint64_t rip;
149 
150     uint64_t eflags;
151 
152     uint16_t cs;
153     uint16_t gs;
154     uint16_t fs;
155     uint16_t ss;
156 
157     uint64_t err;
158     uint64_t trapno;
159     uint64_t oldmask;
160     uint64_t cr2;
161 
162     uint64_t fpstate; /* pointer */
163     uint64_t padding[8];
164 };
165 
166 #ifndef TARGET_X86_64
167 # define target_sigcontext target_sigcontext_32
168 #else
169 # define target_sigcontext target_sigcontext_64
170 #endif
171 
172 /* see Linux/include/uapi/asm-generic/ucontext.h */
173 struct target_ucontext {
174     abi_ulong         tuc_flags;
175     abi_ulong         tuc_link;
176     target_stack_t    tuc_stack;
177     struct target_sigcontext tuc_mcontext;
178     target_sigset_t   tuc_sigmask;  /* mask last for extensibility */
179 };
180 
181 #ifndef TARGET_X86_64
182 struct sigframe {
183     abi_ulong pretcode;
184     int sig;
185     struct target_sigcontext sc;
186     /*
187      * The actual fpstate is placed after retcode[] below, to make
188      * room for the variable-sized xsave data.  The older unused fpstate
189      * has to be kept to avoid changing the offset of extramask[], which
190      * is part of the ABI.
191      */
192     struct target_fpstate fpstate_unused;
193     abi_ulong extramask[TARGET_NSIG_WORDS-1];
194     char retcode[8];
195 
196     /*
197      * This field will be 16-byte aligned in memory.  Applying QEMU_ALIGNED
198      * to it ensures that the base of the frame has an appropriate alignment
199      * too.
200      */
201     struct target_fpstate fpstate QEMU_ALIGNED(8);
202 };
203 #define TARGET_SIGFRAME_FXSAVE_OFFSET (                                    \
204     offsetof(struct sigframe, fpstate) + TARGET_FPSTATE_FXSAVE_OFFSET)
205 
206 struct rt_sigframe {
207     abi_ulong pretcode;
208     int sig;
209     abi_ulong pinfo;
210     abi_ulong puc;
211     struct target_siginfo info;
212     struct target_ucontext uc;
213     char retcode[8];
214     struct target_fpstate fpstate QEMU_ALIGNED(8);
215 };
216 #define TARGET_RT_SIGFRAME_FXSAVE_OFFSET (                                 \
217     offsetof(struct rt_sigframe, fpstate) + TARGET_FPSTATE_FXSAVE_OFFSET)
218 
219 /*
220  * Verify that vdso-asmoffset.h constants match.
221  */
222 #include "i386/vdso-asmoffset.h"
223 
224 QEMU_BUILD_BUG_ON(offsetof(struct sigframe, sc.eip)
225                   != SIGFRAME_SIGCONTEXT_eip);
226 QEMU_BUILD_BUG_ON(offsetof(struct rt_sigframe, uc.tuc_mcontext.eip)
227                   != RT_SIGFRAME_SIGCONTEXT_eip);
228 
229 #else
230 
231 struct rt_sigframe {
232     abi_ulong pretcode;
233     struct target_ucontext uc;
234     struct target_siginfo info;
235     struct target_fpstate fpstate QEMU_ALIGNED(16);
236 };
237 #define TARGET_RT_SIGFRAME_FXSAVE_OFFSET (                                 \
238     offsetof(struct rt_sigframe, fpstate) + TARGET_FPSTATE_FXSAVE_OFFSET)
239 #endif
240 
241 /*
242  * Set up a signal frame.
243  */
244 
245 static void xsave_sigcontext(CPUX86State *env, struct target_fpstate_fxsave *fxsave,
246                              abi_ulong fxsave_addr)
247 {
248     if (!(env->features[FEAT_1_ECX] & CPUID_EXT_XSAVE)) {
249         /* fxsave_addr must be 16 byte aligned for fxsave */
250         assert(!(fxsave_addr & 0xf));
251 
252         cpu_x86_fxsave(env, fxsave_addr);
253         __put_user(0, &fxsave->sw_reserved.magic1);
254     } else {
255         uint32_t xstate_size = xsave_area_size(env->xcr0, false);
256         uint32_t xfeatures_size = xstate_size - TARGET_FXSAVE_SIZE;
257 
258         /*
259          * extended_size is the offset from fpstate_addr to right after the end
260          * of the extended save states.  On 32-bit that includes the legacy
261          * FSAVE area.
262          */
263         uint32_t extended_size = TARGET_FPSTATE_FXSAVE_OFFSET
264             + xstate_size + TARGET_FP_XSTATE_MAGIC2_SIZE;
265 
266         /* fxsave_addr must be 64 byte aligned for xsave */
267         assert(!(fxsave_addr & 0x3f));
268 
269         /* Zero the header, XSAVE *adds* features to an existing save state.  */
270         memset(fxsave->xfeatures, 0, 64);
271         cpu_x86_xsave(env, fxsave_addr);
272         __put_user(TARGET_FP_XSTATE_MAGIC1, &fxsave->sw_reserved.magic1);
273         __put_user(extended_size, &fxsave->sw_reserved.extended_size);
274         __put_user(env->xcr0, &fxsave->sw_reserved.xfeatures);
275         __put_user(xstate_size, &fxsave->sw_reserved.xstate_size);
276         __put_user(TARGET_FP_XSTATE_MAGIC2, (uint32_t *) &fxsave->xfeatures[xfeatures_size]);
277     }
278 }
279 
280 static void setup_sigcontext(struct target_sigcontext *sc,
281         struct target_fpstate *fpstate, CPUX86State *env, abi_ulong mask,
282         abi_ulong fpstate_addr)
283 {
284     CPUState *cs = env_cpu(env);
285 #ifndef TARGET_X86_64
286     uint16_t magic;
287 
288     /* already locked in setup_frame() */
289     __put_user(env->segs[R_GS].selector, (unsigned int *)&sc->gs);
290     __put_user(env->segs[R_FS].selector, (unsigned int *)&sc->fs);
291     __put_user(env->segs[R_ES].selector, (unsigned int *)&sc->es);
292     __put_user(env->segs[R_DS].selector, (unsigned int *)&sc->ds);
293     __put_user(env->regs[R_EDI], &sc->edi);
294     __put_user(env->regs[R_ESI], &sc->esi);
295     __put_user(env->regs[R_EBP], &sc->ebp);
296     __put_user(env->regs[R_ESP], &sc->esp);
297     __put_user(env->regs[R_EBX], &sc->ebx);
298     __put_user(env->regs[R_EDX], &sc->edx);
299     __put_user(env->regs[R_ECX], &sc->ecx);
300     __put_user(env->regs[R_EAX], &sc->eax);
301     __put_user(cs->exception_index, &sc->trapno);
302     __put_user(env->error_code, &sc->err);
303     __put_user(env->eip, &sc->eip);
304     __put_user(env->segs[R_CS].selector, (unsigned int *)&sc->cs);
305     __put_user(env->eflags, &sc->eflags);
306     __put_user(env->regs[R_ESP], &sc->esp_at_signal);
307     __put_user(env->segs[R_SS].selector, (unsigned int *)&sc->ss);
308 
309     cpu_x86_fsave(env, fpstate_addr, 1);
310     fpstate->status = fpstate->sw;
311     if (!(env->features[FEAT_1_EDX] & CPUID_FXSR)) {
312         magic = 0xffff;
313     } else {
314         xsave_sigcontext(env, &fpstate->fxsave,
315                          fpstate_addr + TARGET_FPSTATE_FXSAVE_OFFSET);
316         magic = 0;
317     }
318     __put_user(magic, &fpstate->magic);
319 #else
320     __put_user(env->regs[R_EDI], &sc->rdi);
321     __put_user(env->regs[R_ESI], &sc->rsi);
322     __put_user(env->regs[R_EBP], &sc->rbp);
323     __put_user(env->regs[R_ESP], &sc->rsp);
324     __put_user(env->regs[R_EBX], &sc->rbx);
325     __put_user(env->regs[R_EDX], &sc->rdx);
326     __put_user(env->regs[R_ECX], &sc->rcx);
327     __put_user(env->regs[R_EAX], &sc->rax);
328 
329     __put_user(env->regs[8], &sc->r8);
330     __put_user(env->regs[9], &sc->r9);
331     __put_user(env->regs[10], &sc->r10);
332     __put_user(env->regs[11], &sc->r11);
333     __put_user(env->regs[12], &sc->r12);
334     __put_user(env->regs[13], &sc->r13);
335     __put_user(env->regs[14], &sc->r14);
336     __put_user(env->regs[15], &sc->r15);
337 
338     __put_user(cs->exception_index, &sc->trapno);
339     __put_user(env->error_code, &sc->err);
340     __put_user(env->eip, &sc->rip);
341 
342     __put_user(env->eflags, &sc->eflags);
343     __put_user(env->segs[R_CS].selector, &sc->cs);
344     __put_user((uint16_t)0, &sc->gs);
345     __put_user((uint16_t)0, &sc->fs);
346     __put_user(env->segs[R_SS].selector, &sc->ss);
347 
348     xsave_sigcontext(env, fpstate, fpstate_addr);
349 #endif
350 
351     __put_user(fpstate_addr, &sc->fpstate);
352 
353     /* non-iBCS2 extensions.. */
354     __put_user(mask, &sc->oldmask);
355     __put_user(env->cr[2], &sc->cr2);
356 }
357 
358 /*
359  * Determine which stack to use..
360  */
361 
362 static inline abi_ulong
363 get_sigframe(struct target_sigaction *ka, CPUX86State *env, size_t fxsave_offset)
364 {
365     unsigned long esp;
366 
367     /* Default to using normal stack */
368     esp = get_sp_from_cpustate(env);
369 #ifdef TARGET_X86_64
370     esp -= 128; /* this is the redzone */
371 #endif
372 
373     /* This is the X/Open sanctioned signal stack switching.  */
374     if (ka->sa_flags & TARGET_SA_ONSTACK) {
375         esp = target_sigsp(esp, ka);
376     } else {
377 #ifndef TARGET_X86_64
378         /* This is the legacy signal stack switching. */
379         if ((env->segs[R_SS].selector & 0xffff) != __USER_DS &&
380                 !(ka->sa_flags & TARGET_SA_RESTORER) &&
381                 ka->sa_restorer) {
382             esp = (unsigned long) ka->sa_restorer;
383         }
384 #endif
385     }
386 
387     if (!(env->features[FEAT_1_EDX] & CPUID_FXSR)) {
388         return (esp - (fxsave_offset + TARGET_FXSAVE_SIZE)) & -8ul;
389     } else if (!(env->features[FEAT_1_ECX] & CPUID_EXT_XSAVE)) {
390         return ((esp - TARGET_FXSAVE_SIZE) & -16ul) - fxsave_offset;
391     } else {
392         size_t xstate_size =
393                xsave_area_size(env->xcr0, false) + TARGET_FP_XSTATE_MAGIC2_SIZE;
394         return ((esp - xstate_size) & -64ul) - fxsave_offset;
395     }
396 }
397 
398 #ifndef TARGET_X86_64
399 static void install_sigtramp(void *tramp)
400 {
401     /* This is popl %eax ; movl $syscall,%eax ; int $0x80 */
402     __put_user(0xb858, (uint16_t *)(tramp + 0));
403     __put_user(TARGET_NR_sigreturn, (int32_t *)(tramp + 2));
404     __put_user(0x80cd, (uint16_t *)(tramp + 6));
405 }
406 
407 static void install_rt_sigtramp(void *tramp)
408 {
409     /* This is movl $syscall,%eax ; int $0x80 */
410     __put_user(0xb8, (uint8_t *)(tramp + 0));
411     __put_user(TARGET_NR_rt_sigreturn, (int32_t *)(tramp + 1));
412     __put_user(0x80cd, (uint16_t *)(tramp + 5));
413 }
414 
415 /* compare linux/arch/i386/kernel/signal.c:setup_frame() */
416 void setup_frame(int sig, struct target_sigaction *ka,
417                  target_sigset_t *set, CPUX86State *env)
418 {
419     abi_ulong frame_addr;
420     struct sigframe *frame;
421     int i;
422 
423     frame_addr = get_sigframe(ka, env, TARGET_SIGFRAME_FXSAVE_OFFSET);
424     trace_user_setup_frame(env, frame_addr);
425 
426     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0))
427         goto give_sigsegv;
428 
429     __put_user(sig, &frame->sig);
430 
431     setup_sigcontext(&frame->sc, &frame->fpstate, env, set->sig[0],
432             frame_addr + offsetof(struct sigframe, fpstate));
433 
434     for (i = 1; i < TARGET_NSIG_WORDS; i++) {
435         __put_user(set->sig[i], &frame->extramask[i - 1]);
436     }
437 
438     /* Set up to return from userspace.  If provided, use a stub
439        already in userspace.  */
440     if (ka->sa_flags & TARGET_SA_RESTORER) {
441         __put_user(ka->sa_restorer, &frame->pretcode);
442     } else {
443         /* This is no longer used, but is retained for ABI compatibility. */
444         install_sigtramp(frame->retcode);
445         __put_user(default_sigreturn, &frame->pretcode);
446     }
447 
448     /* Set up registers for signal handler */
449     env->regs[R_ESP] = frame_addr;
450     env->eip = ka->_sa_handler;
451 
452     cpu_x86_load_seg(env, R_DS, __USER_DS);
453     cpu_x86_load_seg(env, R_ES, __USER_DS);
454     cpu_x86_load_seg(env, R_SS, __USER_DS);
455     cpu_x86_load_seg(env, R_CS, __USER_CS);
456     env->eflags &= ~TF_MASK;
457 
458     unlock_user_struct(frame, frame_addr, 1);
459 
460     return;
461 
462 give_sigsegv:
463     force_sigsegv(sig);
464 }
465 #endif
466 
467 /* compare linux/arch/x86/kernel/signal.c:setup_rt_frame() */
468 void setup_rt_frame(int sig, struct target_sigaction *ka,
469                     target_siginfo_t *info,
470                     target_sigset_t *set, CPUX86State *env)
471 {
472     abi_ulong frame_addr;
473 #ifndef TARGET_X86_64
474     abi_ulong addr;
475 #endif
476     struct rt_sigframe *frame;
477     int i;
478 
479     frame_addr = get_sigframe(ka, env, TARGET_RT_SIGFRAME_FXSAVE_OFFSET);
480     trace_user_setup_rt_frame(env, frame_addr);
481 
482     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0))
483         goto give_sigsegv;
484 
485     /* These fields are only in rt_sigframe on 32 bit */
486 #ifndef TARGET_X86_64
487     __put_user(sig, &frame->sig);
488     addr = frame_addr + offsetof(struct rt_sigframe, info);
489     __put_user(addr, &frame->pinfo);
490     addr = frame_addr + offsetof(struct rt_sigframe, uc);
491     __put_user(addr, &frame->puc);
492 #endif
493     if (ka->sa_flags & TARGET_SA_SIGINFO) {
494         frame->info = *info;
495     }
496 
497     /* Create the ucontext.  */
498     if (env->features[FEAT_1_ECX] & CPUID_EXT_XSAVE) {
499         __put_user(1, &frame->uc.tuc_flags);
500     } else {
501         __put_user(0, &frame->uc.tuc_flags);
502     }
503     __put_user(0, &frame->uc.tuc_link);
504     target_save_altstack(&frame->uc.tuc_stack, env);
505     setup_sigcontext(&frame->uc.tuc_mcontext, &frame->fpstate, env,
506             set->sig[0], frame_addr + offsetof(struct rt_sigframe, fpstate));
507 
508     for (i = 0; i < TARGET_NSIG_WORDS; i++) {
509         __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
510     }
511 
512     /* Set up to return from userspace.  If provided, use a stub
513        already in userspace.  */
514     if (ka->sa_flags & TARGET_SA_RESTORER) {
515         __put_user(ka->sa_restorer, &frame->pretcode);
516     } else {
517 #ifdef TARGET_X86_64
518         /* For x86_64, SA_RESTORER is required ABI.  */
519         goto give_sigsegv;
520 #else
521         /* This is no longer used, but is retained for ABI compatibility. */
522         install_rt_sigtramp(frame->retcode);
523         __put_user(default_rt_sigreturn, &frame->pretcode);
524 #endif
525     }
526 
527     /* Set up registers for signal handler */
528     env->regs[R_ESP] = frame_addr;
529     env->eip = ka->_sa_handler;
530 
531 #ifndef TARGET_X86_64
532     env->regs[R_EAX] = sig;
533     env->regs[R_EDX] = frame_addr + offsetof(struct rt_sigframe, info);
534     env->regs[R_ECX] = frame_addr + offsetof(struct rt_sigframe, uc);
535 #else
536     env->regs[R_EAX] = 0;
537     env->regs[R_EDI] = sig;
538     env->regs[R_ESI] = frame_addr + offsetof(struct rt_sigframe, info);
539     env->regs[R_EDX] = frame_addr + offsetof(struct rt_sigframe, uc);
540 #endif
541 
542     cpu_x86_load_seg(env, R_DS, __USER_DS);
543     cpu_x86_load_seg(env, R_ES, __USER_DS);
544     cpu_x86_load_seg(env, R_CS, __USER_CS);
545     cpu_x86_load_seg(env, R_SS, __USER_DS);
546     env->eflags &= ~TF_MASK;
547 
548     unlock_user_struct(frame, frame_addr, 1);
549 
550     return;
551 
552 give_sigsegv:
553     force_sigsegv(sig);
554 }
555 
556 static int xrstor_sigcontext(CPUX86State *env, struct target_fpstate_fxsave *fxsave,
557                              abi_ulong fxsave_addr)
558 {
559     if (env->features[FEAT_1_ECX] & CPUID_EXT_XSAVE) {
560         uint32_t extended_size = tswapl(fxsave->sw_reserved.extended_size);
561         uint32_t xstate_size = tswapl(fxsave->sw_reserved.xstate_size);
562         uint32_t xfeatures_size = xstate_size - TARGET_FXSAVE_SIZE;
563 
564         /* Linux checks MAGIC2 using xstate_size, not extended_size.  */
565         if (tswapl(fxsave->sw_reserved.magic1) == TARGET_FP_XSTATE_MAGIC1 &&
566             extended_size >= TARGET_FPSTATE_FXSAVE_OFFSET + xstate_size + TARGET_FP_XSTATE_MAGIC2_SIZE) {
567             if (!access_ok(env_cpu(env), VERIFY_READ, fxsave_addr,
568                            extended_size - TARGET_FPSTATE_FXSAVE_OFFSET)) {
569                 return 1;
570             }
571             if (tswapl(*(uint32_t *) &fxsave->xfeatures[xfeatures_size]) == TARGET_FP_XSTATE_MAGIC2) {
572                 cpu_x86_xrstor(env, fxsave_addr);
573                 return 0;
574             }
575         }
576         /* fall through to fxrstor */
577     }
578 
579     cpu_x86_fxrstor(env, fxsave_addr);
580     return 0;
581 }
582 
583 static int
584 restore_sigcontext(CPUX86State *env, struct target_sigcontext *sc)
585 {
586     int err = 1;
587     abi_ulong fpstate_addr;
588     unsigned int tmpflags;
589 
590 #ifndef TARGET_X86_64
591     cpu_x86_load_seg(env, R_GS, tswap16(sc->gs));
592     cpu_x86_load_seg(env, R_FS, tswap16(sc->fs));
593     cpu_x86_load_seg(env, R_ES, tswap16(sc->es));
594     cpu_x86_load_seg(env, R_DS, tswap16(sc->ds));
595 
596     env->regs[R_EDI] = tswapl(sc->edi);
597     env->regs[R_ESI] = tswapl(sc->esi);
598     env->regs[R_EBP] = tswapl(sc->ebp);
599     env->regs[R_ESP] = tswapl(sc->esp);
600     env->regs[R_EBX] = tswapl(sc->ebx);
601     env->regs[R_EDX] = tswapl(sc->edx);
602     env->regs[R_ECX] = tswapl(sc->ecx);
603     env->regs[R_EAX] = tswapl(sc->eax);
604 
605     env->eip = tswapl(sc->eip);
606 #else
607     env->regs[8] = tswapl(sc->r8);
608     env->regs[9] = tswapl(sc->r9);
609     env->regs[10] = tswapl(sc->r10);
610     env->regs[11] = tswapl(sc->r11);
611     env->regs[12] = tswapl(sc->r12);
612     env->regs[13] = tswapl(sc->r13);
613     env->regs[14] = tswapl(sc->r14);
614     env->regs[15] = tswapl(sc->r15);
615 
616     env->regs[R_EDI] = tswapl(sc->rdi);
617     env->regs[R_ESI] = tswapl(sc->rsi);
618     env->regs[R_EBP] = tswapl(sc->rbp);
619     env->regs[R_EBX] = tswapl(sc->rbx);
620     env->regs[R_EDX] = tswapl(sc->rdx);
621     env->regs[R_EAX] = tswapl(sc->rax);
622     env->regs[R_ECX] = tswapl(sc->rcx);
623     env->regs[R_ESP] = tswapl(sc->rsp);
624 
625     env->eip = tswapl(sc->rip);
626 #endif
627 
628     cpu_x86_load_seg(env, R_CS, lduw_p(&sc->cs) | 3);
629     cpu_x86_load_seg(env, R_SS, lduw_p(&sc->ss) | 3);
630 
631     tmpflags = tswapl(sc->eflags);
632     env->eflags = (env->eflags & ~0x40DD5) | (tmpflags & 0x40DD5);
633     //          regs->orig_eax = -1;            /* disable syscall checks */
634 
635     fpstate_addr = tswapl(sc->fpstate);
636     if (fpstate_addr != 0) {
637         struct target_fpstate *fpstate;
638         if (!lock_user_struct(VERIFY_READ, fpstate, fpstate_addr,
639                               sizeof(struct target_fpstate))) {
640             return err;
641         }
642 #ifndef TARGET_X86_64
643         if (!(env->features[FEAT_1_EDX] & CPUID_FXSR)) {
644             cpu_x86_frstor(env, fpstate_addr, 1);
645             err = 0;
646         } else {
647             err = xrstor_sigcontext(env, &fpstate->fxsave,
648                                     fpstate_addr + TARGET_FPSTATE_FXSAVE_OFFSET);
649         }
650 #else
651         err = xrstor_sigcontext(env, fpstate, fpstate_addr);
652 #endif
653         unlock_user_struct(fpstate, fpstate_addr, 0);
654     } else {
655         err = 0;
656     }
657 
658     return err;
659 }
660 
661 /* Note: there is no sigreturn on x86_64, there is only rt_sigreturn */
662 #ifndef TARGET_X86_64
663 long do_sigreturn(CPUX86State *env)
664 {
665     struct sigframe *frame;
666     abi_ulong frame_addr = env->regs[R_ESP] - 8;
667     target_sigset_t target_set;
668     sigset_t set;
669     int i;
670 
671     trace_user_do_sigreturn(env, frame_addr);
672     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))
673         goto badframe;
674     /* set blocked signals */
675     __get_user(target_set.sig[0], &frame->sc.oldmask);
676     for(i = 1; i < TARGET_NSIG_WORDS; i++) {
677         __get_user(target_set.sig[i], &frame->extramask[i - 1]);
678     }
679 
680     target_to_host_sigset_internal(&set, &target_set);
681     set_sigmask(&set);
682 
683     /* restore registers */
684     if (restore_sigcontext(env, &frame->sc))
685         goto badframe;
686     unlock_user_struct(frame, frame_addr, 0);
687     return -QEMU_ESIGRETURN;
688 
689 badframe:
690     unlock_user_struct(frame, frame_addr, 0);
691     force_sig(TARGET_SIGSEGV);
692     return -QEMU_ESIGRETURN;
693 }
694 #endif
695 
696 long do_rt_sigreturn(CPUX86State *env)
697 {
698     abi_ulong frame_addr;
699     struct rt_sigframe *frame;
700     sigset_t set;
701 
702     frame_addr = env->regs[R_ESP] - sizeof(abi_ulong);
703     trace_user_do_rt_sigreturn(env, frame_addr);
704     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))
705         goto badframe;
706     target_to_host_sigset(&set, &frame->uc.tuc_sigmask);
707     set_sigmask(&set);
708 
709     if (restore_sigcontext(env, &frame->uc.tuc_mcontext)) {
710         goto badframe;
711     }
712 
713     target_restore_altstack(&frame->uc.tuc_stack, env);
714 
715     unlock_user_struct(frame, frame_addr, 0);
716     return -QEMU_ESIGRETURN;
717 
718 badframe:
719     unlock_user_struct(frame, frame_addr, 0);
720     force_sig(TARGET_SIGSEGV);
721     return -QEMU_ESIGRETURN;
722 }
723 
724 #ifndef TARGET_X86_64
725 void setup_sigtramp(abi_ulong sigtramp_page)
726 {
727     uint16_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 2 * 8, 0);
728     assert(tramp != NULL);
729 
730     default_sigreturn = sigtramp_page;
731     install_sigtramp(tramp);
732 
733     default_rt_sigreturn = sigtramp_page + 8;
734     install_rt_sigtramp(tramp + 8);
735 
736     unlock_user(tramp, sigtramp_page, 2 * 8);
737 }
738 #endif
739