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signal.c (22281B)


      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 /* from the Linux kernel - /arch/x86/include/uapi/asm/sigcontext.h */
     26 
     27 #define TARGET_FP_XSTATE_MAGIC1         0x46505853U /* FPXS */
     28 #define TARGET_FP_XSTATE_MAGIC2         0x46505845U /* FPXE */
     29 #define TARGET_FP_XSTATE_MAGIC2_SIZE    4
     30 
     31 struct target_fpreg {
     32     uint16_t significand[4];
     33     uint16_t exponent;
     34 };
     35 
     36 struct target_fpxreg {
     37     uint16_t significand[4];
     38     uint16_t exponent;
     39     uint16_t padding[3];
     40 };
     41 
     42 struct target_xmmreg {
     43     uint32_t element[4];
     44 };
     45 
     46 struct target_fpx_sw_bytes {
     47     uint32_t magic1;
     48     uint32_t extended_size;
     49     uint64_t xfeatures;
     50     uint32_t xstate_size;
     51     uint32_t reserved[7];
     52 };
     53 QEMU_BUILD_BUG_ON(sizeof(struct target_fpx_sw_bytes) != 12*4);
     54 
     55 struct target_fpstate_fxsave {
     56     /* FXSAVE format */
     57     uint16_t cw;
     58     uint16_t sw;
     59     uint16_t twd;
     60     uint16_t fop;
     61     uint64_t rip;
     62     uint64_t rdp;
     63     uint32_t mxcsr;
     64     uint32_t mxcsr_mask;
     65     uint32_t st_space[32];
     66     uint32_t xmm_space[64];
     67     uint32_t hw_reserved[12];
     68     struct target_fpx_sw_bytes sw_reserved;
     69     uint8_t xfeatures[];
     70 };
     71 #define TARGET_FXSAVE_SIZE   sizeof(struct target_fpstate_fxsave)
     72 QEMU_BUILD_BUG_ON(TARGET_FXSAVE_SIZE != 512);
     73 QEMU_BUILD_BUG_ON(offsetof(struct target_fpstate_fxsave, sw_reserved) != 464);
     74 
     75 struct target_fpstate_32 {
     76     /* Regular FPU environment */
     77     uint32_t cw;
     78     uint32_t sw;
     79     uint32_t tag;
     80     uint32_t ipoff;
     81     uint32_t cssel;
     82     uint32_t dataoff;
     83     uint32_t datasel;
     84     struct target_fpreg st[8];
     85     uint16_t  status;
     86     uint16_t  magic;          /* 0xffff = regular FPU data only */
     87     struct target_fpstate_fxsave fxsave;
     88 };
     89 
     90 /*
     91  * For simplicity, setup_frame aligns struct target_fpstate_32 to
     92  * 16 bytes, so ensure that the FXSAVE area is also aligned.
     93  */
     94 QEMU_BUILD_BUG_ON(offsetof(struct target_fpstate_32, fxsave) & 15);
     95 
     96 #ifndef TARGET_X86_64
     97 # define target_fpstate target_fpstate_32
     98 # define TARGET_FPSTATE_FXSAVE_OFFSET offsetof(struct target_fpstate_32, fxsave)
     99 #else
    100 # define target_fpstate target_fpstate_fxsave
    101 # define TARGET_FPSTATE_FXSAVE_OFFSET 0
    102 #endif
    103 
    104 struct target_sigcontext_32 {
    105     uint16_t gs, __gsh;
    106     uint16_t fs, __fsh;
    107     uint16_t es, __esh;
    108     uint16_t ds, __dsh;
    109     uint32_t edi;
    110     uint32_t esi;
    111     uint32_t ebp;
    112     uint32_t esp;
    113     uint32_t ebx;
    114     uint32_t edx;
    115     uint32_t ecx;
    116     uint32_t eax;
    117     uint32_t trapno;
    118     uint32_t err;
    119     uint32_t eip;
    120     uint16_t cs, __csh;
    121     uint32_t eflags;
    122     uint32_t esp_at_signal;
    123     uint16_t ss, __ssh;
    124     uint32_t fpstate; /* pointer */
    125     uint32_t oldmask;
    126     uint32_t cr2;
    127 };
    128 
    129 struct target_sigcontext_64 {
    130     uint64_t r8;
    131     uint64_t r9;
    132     uint64_t r10;
    133     uint64_t r11;
    134     uint64_t r12;
    135     uint64_t r13;
    136     uint64_t r14;
    137     uint64_t r15;
    138 
    139     uint64_t rdi;
    140     uint64_t rsi;
    141     uint64_t rbp;
    142     uint64_t rbx;
    143     uint64_t rdx;
    144     uint64_t rax;
    145     uint64_t rcx;
    146     uint64_t rsp;
    147     uint64_t rip;
    148 
    149     uint64_t eflags;
    150 
    151     uint16_t cs;
    152     uint16_t gs;
    153     uint16_t fs;
    154     uint16_t ss;
    155 
    156     uint64_t err;
    157     uint64_t trapno;
    158     uint64_t oldmask;
    159     uint64_t cr2;
    160 
    161     uint64_t fpstate; /* pointer */
    162     uint64_t padding[8];
    163 };
    164 
    165 #ifndef TARGET_X86_64
    166 # define target_sigcontext target_sigcontext_32
    167 #else
    168 # define target_sigcontext target_sigcontext_64
    169 #endif
    170 
    171 /* see Linux/include/uapi/asm-generic/ucontext.h */
    172 struct target_ucontext {
    173     abi_ulong         tuc_flags;
    174     abi_ulong         tuc_link;
    175     target_stack_t    tuc_stack;
    176     struct target_sigcontext tuc_mcontext;
    177     target_sigset_t   tuc_sigmask;  /* mask last for extensibility */
    178 };
    179 
    180 #ifndef TARGET_X86_64
    181 struct sigframe {
    182     abi_ulong pretcode;
    183     int sig;
    184     struct target_sigcontext sc;
    185     /*
    186      * The actual fpstate is placed after retcode[] below, to make
    187      * room for the variable-sized xsave data.  The older unused fpstate
    188      * has to be kept to avoid changing the offset of extramask[], which
    189      * is part of the ABI.
    190      */
    191     struct target_fpstate fpstate_unused;
    192     abi_ulong extramask[TARGET_NSIG_WORDS-1];
    193     char retcode[8];
    194 
    195     /*
    196      * This field will be 16-byte aligned in memory.  Applying QEMU_ALIGNED
    197      * to it ensures that the base of the frame has an appropriate alignment
    198      * too.
    199      */
    200     struct target_fpstate fpstate QEMU_ALIGNED(8);
    201 };
    202 #define TARGET_SIGFRAME_FXSAVE_OFFSET (                                    \
    203     offsetof(struct sigframe, fpstate) + TARGET_FPSTATE_FXSAVE_OFFSET)
    204 
    205 struct rt_sigframe {
    206     abi_ulong pretcode;
    207     int sig;
    208     abi_ulong pinfo;
    209     abi_ulong puc;
    210     struct target_siginfo info;
    211     struct target_ucontext uc;
    212     char retcode[8];
    213     struct target_fpstate fpstate QEMU_ALIGNED(8);
    214 };
    215 #define TARGET_RT_SIGFRAME_FXSAVE_OFFSET (                                 \
    216     offsetof(struct rt_sigframe, fpstate) + TARGET_FPSTATE_FXSAVE_OFFSET)
    217 #else
    218 
    219 struct rt_sigframe {
    220     abi_ulong pretcode;
    221     struct target_ucontext uc;
    222     struct target_siginfo info;
    223     struct target_fpstate fpstate QEMU_ALIGNED(16);
    224 };
    225 #define TARGET_RT_SIGFRAME_FXSAVE_OFFSET (                                 \
    226     offsetof(struct rt_sigframe, fpstate) + TARGET_FPSTATE_FXSAVE_OFFSET)
    227 #endif
    228 
    229 /*
    230  * Set up a signal frame.
    231  */
    232 
    233 static void xsave_sigcontext(CPUX86State *env, struct target_fpstate_fxsave *fxsave,
    234                              abi_ulong fxsave_addr)
    235 {
    236     if (!(env->features[FEAT_1_ECX] & CPUID_EXT_XSAVE)) {
    237         /* fxsave_addr must be 16 byte aligned for fxsave */
    238         assert(!(fxsave_addr & 0xf));
    239 
    240         cpu_x86_fxsave(env, fxsave_addr);
    241         __put_user(0, &fxsave->sw_reserved.magic1);
    242     } else {
    243         uint32_t xstate_size = xsave_area_size(env->xcr0, false);
    244         uint32_t xfeatures_size = xstate_size - TARGET_FXSAVE_SIZE;
    245 
    246         /*
    247          * extended_size is the offset from fpstate_addr to right after the end
    248          * of the extended save states.  On 32-bit that includes the legacy
    249          * FSAVE area.
    250          */
    251         uint32_t extended_size = TARGET_FPSTATE_FXSAVE_OFFSET
    252             + xstate_size + TARGET_FP_XSTATE_MAGIC2_SIZE;
    253 
    254         /* fxsave_addr must be 64 byte aligned for xsave */
    255         assert(!(fxsave_addr & 0x3f));
    256 
    257         /* Zero the header, XSAVE *adds* features to an existing save state.  */
    258         memset(fxsave->xfeatures, 0, 64);
    259         cpu_x86_xsave(env, fxsave_addr);
    260         __put_user(TARGET_FP_XSTATE_MAGIC1, &fxsave->sw_reserved.magic1);
    261         __put_user(extended_size, &fxsave->sw_reserved.extended_size);
    262         __put_user(env->xcr0, &fxsave->sw_reserved.xfeatures);
    263         __put_user(xstate_size, &fxsave->sw_reserved.xstate_size);
    264         __put_user(TARGET_FP_XSTATE_MAGIC2, (uint32_t *) &fxsave->xfeatures[xfeatures_size]);
    265     }
    266 }
    267 
    268 static void setup_sigcontext(struct target_sigcontext *sc,
    269         struct target_fpstate *fpstate, CPUX86State *env, abi_ulong mask,
    270         abi_ulong fpstate_addr)
    271 {
    272     CPUState *cs = env_cpu(env);
    273 #ifndef TARGET_X86_64
    274     uint16_t magic;
    275 
    276     /* already locked in setup_frame() */
    277     __put_user(env->segs[R_GS].selector, (unsigned int *)&sc->gs);
    278     __put_user(env->segs[R_FS].selector, (unsigned int *)&sc->fs);
    279     __put_user(env->segs[R_ES].selector, (unsigned int *)&sc->es);
    280     __put_user(env->segs[R_DS].selector, (unsigned int *)&sc->ds);
    281     __put_user(env->regs[R_EDI], &sc->edi);
    282     __put_user(env->regs[R_ESI], &sc->esi);
    283     __put_user(env->regs[R_EBP], &sc->ebp);
    284     __put_user(env->regs[R_ESP], &sc->esp);
    285     __put_user(env->regs[R_EBX], &sc->ebx);
    286     __put_user(env->regs[R_EDX], &sc->edx);
    287     __put_user(env->regs[R_ECX], &sc->ecx);
    288     __put_user(env->regs[R_EAX], &sc->eax);
    289     __put_user(cs->exception_index, &sc->trapno);
    290     __put_user(env->error_code, &sc->err);
    291     __put_user(env->eip, &sc->eip);
    292     __put_user(env->segs[R_CS].selector, (unsigned int *)&sc->cs);
    293     __put_user(env->eflags, &sc->eflags);
    294     __put_user(env->regs[R_ESP], &sc->esp_at_signal);
    295     __put_user(env->segs[R_SS].selector, (unsigned int *)&sc->ss);
    296 
    297     cpu_x86_fsave(env, fpstate_addr, 1);
    298     fpstate->status = fpstate->sw;
    299     if (!(env->features[FEAT_1_EDX] & CPUID_FXSR)) {
    300         magic = 0xffff;
    301     } else {
    302         xsave_sigcontext(env, &fpstate->fxsave,
    303                          fpstate_addr + TARGET_FPSTATE_FXSAVE_OFFSET);
    304         magic = 0;
    305     }
    306     __put_user(magic, &fpstate->magic);
    307 #else
    308     __put_user(env->regs[R_EDI], &sc->rdi);
    309     __put_user(env->regs[R_ESI], &sc->rsi);
    310     __put_user(env->regs[R_EBP], &sc->rbp);
    311     __put_user(env->regs[R_ESP], &sc->rsp);
    312     __put_user(env->regs[R_EBX], &sc->rbx);
    313     __put_user(env->regs[R_EDX], &sc->rdx);
    314     __put_user(env->regs[R_ECX], &sc->rcx);
    315     __put_user(env->regs[R_EAX], &sc->rax);
    316 
    317     __put_user(env->regs[8], &sc->r8);
    318     __put_user(env->regs[9], &sc->r9);
    319     __put_user(env->regs[10], &sc->r10);
    320     __put_user(env->regs[11], &sc->r11);
    321     __put_user(env->regs[12], &sc->r12);
    322     __put_user(env->regs[13], &sc->r13);
    323     __put_user(env->regs[14], &sc->r14);
    324     __put_user(env->regs[15], &sc->r15);
    325 
    326     __put_user(cs->exception_index, &sc->trapno);
    327     __put_user(env->error_code, &sc->err);
    328     __put_user(env->eip, &sc->rip);
    329 
    330     __put_user(env->eflags, &sc->eflags);
    331     __put_user(env->segs[R_CS].selector, &sc->cs);
    332     __put_user((uint16_t)0, &sc->gs);
    333     __put_user((uint16_t)0, &sc->fs);
    334     __put_user(env->segs[R_SS].selector, &sc->ss);
    335 
    336     xsave_sigcontext(env, fpstate, fpstate_addr);
    337 #endif
    338 
    339     __put_user(fpstate_addr, &sc->fpstate);
    340 
    341     /* non-iBCS2 extensions.. */
    342     __put_user(mask, &sc->oldmask);
    343     __put_user(env->cr[2], &sc->cr2);
    344 }
    345 
    346 /*
    347  * Determine which stack to use..
    348  */
    349 
    350 static inline abi_ulong
    351 get_sigframe(struct target_sigaction *ka, CPUX86State *env, size_t fxsave_offset)
    352 {
    353     unsigned long esp;
    354 
    355     /* Default to using normal stack */
    356     esp = get_sp_from_cpustate(env);
    357 #ifdef TARGET_X86_64
    358     esp -= 128; /* this is the redzone */
    359 #endif
    360 
    361     /* This is the X/Open sanctioned signal stack switching.  */
    362     if (ka->sa_flags & TARGET_SA_ONSTACK) {
    363         esp = target_sigsp(esp, ka);
    364     } else {
    365 #ifndef TARGET_X86_64
    366         /* This is the legacy signal stack switching. */
    367         if ((env->segs[R_SS].selector & 0xffff) != __USER_DS &&
    368                 !(ka->sa_flags & TARGET_SA_RESTORER) &&
    369                 ka->sa_restorer) {
    370             esp = (unsigned long) ka->sa_restorer;
    371         }
    372 #endif
    373     }
    374 
    375     if (!(env->features[FEAT_1_EDX] & CPUID_FXSR)) {
    376         return (esp - (fxsave_offset + TARGET_FXSAVE_SIZE)) & -8ul;
    377     } else if (!(env->features[FEAT_1_ECX] & CPUID_EXT_XSAVE)) {
    378         return ((esp - TARGET_FXSAVE_SIZE) & -16ul) - fxsave_offset;
    379     } else {
    380         size_t xstate_size =
    381                xsave_area_size(env->xcr0, false) + TARGET_FP_XSTATE_MAGIC2_SIZE;
    382         return ((esp - xstate_size) & -64ul) - fxsave_offset;
    383     }
    384 }
    385 
    386 #ifndef TARGET_X86_64
    387 static void install_sigtramp(void *tramp)
    388 {
    389     /* This is popl %eax ; movl $syscall,%eax ; int $0x80 */
    390     __put_user(0xb858, (uint16_t *)(tramp + 0));
    391     __put_user(TARGET_NR_sigreturn, (int32_t *)(tramp + 2));
    392     __put_user(0x80cd, (uint16_t *)(tramp + 6));
    393 }
    394 
    395 static void install_rt_sigtramp(void *tramp)
    396 {
    397     /* This is movl $syscall,%eax ; int $0x80 */
    398     __put_user(0xb8, (uint8_t *)(tramp + 0));
    399     __put_user(TARGET_NR_rt_sigreturn, (int32_t *)(tramp + 1));
    400     __put_user(0x80cd, (uint16_t *)(tramp + 5));
    401 }
    402 
    403 /* compare linux/arch/i386/kernel/signal.c:setup_frame() */
    404 void setup_frame(int sig, struct target_sigaction *ka,
    405                  target_sigset_t *set, CPUX86State *env)
    406 {
    407     abi_ulong frame_addr;
    408     struct sigframe *frame;
    409     int i;
    410 
    411     frame_addr = get_sigframe(ka, env, TARGET_SIGFRAME_FXSAVE_OFFSET);
    412     trace_user_setup_frame(env, frame_addr);
    413 
    414     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0))
    415         goto give_sigsegv;
    416 
    417     __put_user(sig, &frame->sig);
    418 
    419     setup_sigcontext(&frame->sc, &frame->fpstate, env, set->sig[0],
    420             frame_addr + offsetof(struct sigframe, fpstate));
    421 
    422     for(i = 1; i < TARGET_NSIG_WORDS; i++) {
    423         __put_user(set->sig[i], &frame->extramask[i - 1]);
    424     }
    425 
    426     /* Set up to return from userspace.  If provided, use a stub
    427        already in userspace.  */
    428     if (ka->sa_flags & TARGET_SA_RESTORER) {
    429         __put_user(ka->sa_restorer, &frame->pretcode);
    430     } else {
    431         /* This is no longer used, but is retained for ABI compatibility. */
    432         install_sigtramp(frame->retcode);
    433         __put_user(default_sigreturn, &frame->pretcode);
    434     }
    435 
    436     /* Set up registers for signal handler */
    437     env->regs[R_ESP] = frame_addr;
    438     env->eip = ka->_sa_handler;
    439 
    440     cpu_x86_load_seg(env, R_DS, __USER_DS);
    441     cpu_x86_load_seg(env, R_ES, __USER_DS);
    442     cpu_x86_load_seg(env, R_SS, __USER_DS);
    443     cpu_x86_load_seg(env, R_CS, __USER_CS);
    444     env->eflags &= ~TF_MASK;
    445 
    446     unlock_user_struct(frame, frame_addr, 1);
    447 
    448     return;
    449 
    450 give_sigsegv:
    451     force_sigsegv(sig);
    452 }
    453 #endif
    454 
    455 /* compare linux/arch/x86/kernel/signal.c:setup_rt_frame() */
    456 void setup_rt_frame(int sig, struct target_sigaction *ka,
    457                     target_siginfo_t *info,
    458                     target_sigset_t *set, CPUX86State *env)
    459 {
    460     abi_ulong frame_addr;
    461 #ifndef TARGET_X86_64
    462     abi_ulong addr;
    463 #endif
    464     struct rt_sigframe *frame;
    465     int i;
    466 
    467     frame_addr = get_sigframe(ka, env, TARGET_RT_SIGFRAME_FXSAVE_OFFSET);
    468     trace_user_setup_rt_frame(env, frame_addr);
    469 
    470     if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0))
    471         goto give_sigsegv;
    472 
    473     /* These fields are only in rt_sigframe on 32 bit */
    474 #ifndef TARGET_X86_64
    475     __put_user(sig, &frame->sig);
    476     addr = frame_addr + offsetof(struct rt_sigframe, info);
    477     __put_user(addr, &frame->pinfo);
    478     addr = frame_addr + offsetof(struct rt_sigframe, uc);
    479     __put_user(addr, &frame->puc);
    480 #endif
    481     if (ka->sa_flags & TARGET_SA_SIGINFO) {
    482         tswap_siginfo(&frame->info, info);
    483     }
    484 
    485     /* Create the ucontext.  */
    486     if (env->features[FEAT_1_ECX] & CPUID_EXT_XSAVE) {
    487         __put_user(1, &frame->uc.tuc_flags);
    488     } else {
    489         __put_user(0, &frame->uc.tuc_flags);
    490     }
    491     __put_user(0, &frame->uc.tuc_link);
    492     target_save_altstack(&frame->uc.tuc_stack, env);
    493     setup_sigcontext(&frame->uc.tuc_mcontext, &frame->fpstate, env,
    494             set->sig[0], frame_addr + offsetof(struct rt_sigframe, fpstate));
    495 
    496     for(i = 0; i < TARGET_NSIG_WORDS; i++) {
    497         __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
    498     }
    499 
    500     /* Set up to return from userspace.  If provided, use a stub
    501        already in userspace.  */
    502     if (ka->sa_flags & TARGET_SA_RESTORER) {
    503         __put_user(ka->sa_restorer, &frame->pretcode);
    504     } else {
    505 #ifdef TARGET_X86_64
    506         /* For x86_64, SA_RESTORER is required ABI.  */
    507         goto give_sigsegv;
    508 #else
    509         /* This is no longer used, but is retained for ABI compatibility. */
    510         install_rt_sigtramp(frame->retcode);
    511         __put_user(default_rt_sigreturn, &frame->pretcode);
    512 #endif
    513     }
    514 
    515     /* Set up registers for signal handler */
    516     env->regs[R_ESP] = frame_addr;
    517     env->eip = ka->_sa_handler;
    518 
    519 #ifndef TARGET_X86_64
    520     env->regs[R_EAX] = sig;
    521     env->regs[R_EDX] = frame_addr + offsetof(struct rt_sigframe, info);
    522     env->regs[R_ECX] = frame_addr + offsetof(struct rt_sigframe, uc);
    523 #else
    524     env->regs[R_EAX] = 0;
    525     env->regs[R_EDI] = sig;
    526     env->regs[R_ESI] = frame_addr + offsetof(struct rt_sigframe, info);
    527     env->regs[R_EDX] = frame_addr + offsetof(struct rt_sigframe, uc);
    528 #endif
    529 
    530     cpu_x86_load_seg(env, R_DS, __USER_DS);
    531     cpu_x86_load_seg(env, R_ES, __USER_DS);
    532     cpu_x86_load_seg(env, R_CS, __USER_CS);
    533     cpu_x86_load_seg(env, R_SS, __USER_DS);
    534     env->eflags &= ~TF_MASK;
    535 
    536     unlock_user_struct(frame, frame_addr, 1);
    537 
    538     return;
    539 
    540 give_sigsegv:
    541     force_sigsegv(sig);
    542 }
    543 
    544 static int xrstor_sigcontext(CPUX86State *env, struct target_fpstate_fxsave *fxsave,
    545                              abi_ulong fxsave_addr)
    546 {
    547     if (env->features[FEAT_1_ECX] & CPUID_EXT_XSAVE) {
    548         uint32_t extended_size = tswapl(fxsave->sw_reserved.extended_size);
    549         uint32_t xstate_size = tswapl(fxsave->sw_reserved.xstate_size);
    550         uint32_t xfeatures_size = xstate_size - TARGET_FXSAVE_SIZE;
    551 
    552         /* Linux checks MAGIC2 using xstate_size, not extended_size.  */
    553         if (tswapl(fxsave->sw_reserved.magic1) == TARGET_FP_XSTATE_MAGIC1 &&
    554             extended_size >= TARGET_FPSTATE_FXSAVE_OFFSET + xstate_size + TARGET_FP_XSTATE_MAGIC2_SIZE) {
    555             if (!access_ok(env_cpu(env), VERIFY_READ, fxsave_addr,
    556                            extended_size - TARGET_FPSTATE_FXSAVE_OFFSET)) {
    557                 return 1;
    558             }
    559             if (tswapl(*(uint32_t *) &fxsave->xfeatures[xfeatures_size]) == TARGET_FP_XSTATE_MAGIC2) {
    560                 cpu_x86_xrstor(env, fxsave_addr);
    561                 return 0;
    562             }
    563         }
    564         /* fall through to fxrstor */
    565     }
    566 
    567     cpu_x86_fxrstor(env, fxsave_addr);
    568     return 0;
    569 }
    570 
    571 static int
    572 restore_sigcontext(CPUX86State *env, struct target_sigcontext *sc)
    573 {
    574     int err = 1;
    575     abi_ulong fpstate_addr;
    576     unsigned int tmpflags;
    577 
    578 #ifndef TARGET_X86_64
    579     cpu_x86_load_seg(env, R_GS, tswap16(sc->gs));
    580     cpu_x86_load_seg(env, R_FS, tswap16(sc->fs));
    581     cpu_x86_load_seg(env, R_ES, tswap16(sc->es));
    582     cpu_x86_load_seg(env, R_DS, tswap16(sc->ds));
    583 
    584     env->regs[R_EDI] = tswapl(sc->edi);
    585     env->regs[R_ESI] = tswapl(sc->esi);
    586     env->regs[R_EBP] = tswapl(sc->ebp);
    587     env->regs[R_ESP] = tswapl(sc->esp);
    588     env->regs[R_EBX] = tswapl(sc->ebx);
    589     env->regs[R_EDX] = tswapl(sc->edx);
    590     env->regs[R_ECX] = tswapl(sc->ecx);
    591     env->regs[R_EAX] = tswapl(sc->eax);
    592 
    593     env->eip = tswapl(sc->eip);
    594 #else
    595     env->regs[8] = tswapl(sc->r8);
    596     env->regs[9] = tswapl(sc->r9);
    597     env->regs[10] = tswapl(sc->r10);
    598     env->regs[11] = tswapl(sc->r11);
    599     env->regs[12] = tswapl(sc->r12);
    600     env->regs[13] = tswapl(sc->r13);
    601     env->regs[14] = tswapl(sc->r14);
    602     env->regs[15] = tswapl(sc->r15);
    603 
    604     env->regs[R_EDI] = tswapl(sc->rdi);
    605     env->regs[R_ESI] = tswapl(sc->rsi);
    606     env->regs[R_EBP] = tswapl(sc->rbp);
    607     env->regs[R_EBX] = tswapl(sc->rbx);
    608     env->regs[R_EDX] = tswapl(sc->rdx);
    609     env->regs[R_EAX] = tswapl(sc->rax);
    610     env->regs[R_ECX] = tswapl(sc->rcx);
    611     env->regs[R_ESP] = tswapl(sc->rsp);
    612 
    613     env->eip = tswapl(sc->rip);
    614 #endif
    615 
    616     cpu_x86_load_seg(env, R_CS, lduw_p(&sc->cs) | 3);
    617     cpu_x86_load_seg(env, R_SS, lduw_p(&sc->ss) | 3);
    618 
    619     tmpflags = tswapl(sc->eflags);
    620     env->eflags = (env->eflags & ~0x40DD5) | (tmpflags & 0x40DD5);
    621     //          regs->orig_eax = -1;            /* disable syscall checks */
    622 
    623     fpstate_addr = tswapl(sc->fpstate);
    624     if (fpstate_addr != 0) {
    625         struct target_fpstate *fpstate;
    626         if (!lock_user_struct(VERIFY_READ, fpstate, fpstate_addr,
    627                               sizeof(struct target_fpstate))) {
    628             return err;
    629         }
    630 #ifndef TARGET_X86_64
    631         if (!(env->features[FEAT_1_EDX] & CPUID_FXSR)) {
    632             cpu_x86_frstor(env, fpstate_addr, 1);
    633             err = 0;
    634         } else {
    635             err = xrstor_sigcontext(env, &fpstate->fxsave,
    636                                     fpstate_addr + TARGET_FPSTATE_FXSAVE_OFFSET);
    637         }
    638 #else
    639         err = xrstor_sigcontext(env, fpstate, fpstate_addr);
    640 #endif
    641         unlock_user_struct(fpstate, fpstate_addr, 0);
    642     } else {
    643         err = 0;
    644     }
    645 
    646     return err;
    647 }
    648 
    649 /* Note: there is no sigreturn on x86_64, there is only rt_sigreturn */
    650 #ifndef TARGET_X86_64
    651 long do_sigreturn(CPUX86State *env)
    652 {
    653     struct sigframe *frame;
    654     abi_ulong frame_addr = env->regs[R_ESP] - 8;
    655     target_sigset_t target_set;
    656     sigset_t set;
    657     int i;
    658 
    659     trace_user_do_sigreturn(env, frame_addr);
    660     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))
    661         goto badframe;
    662     /* set blocked signals */
    663     __get_user(target_set.sig[0], &frame->sc.oldmask);
    664     for(i = 1; i < TARGET_NSIG_WORDS; i++) {
    665         __get_user(target_set.sig[i], &frame->extramask[i - 1]);
    666     }
    667 
    668     target_to_host_sigset_internal(&set, &target_set);
    669     set_sigmask(&set);
    670 
    671     /* restore registers */
    672     if (restore_sigcontext(env, &frame->sc))
    673         goto badframe;
    674     unlock_user_struct(frame, frame_addr, 0);
    675     return -QEMU_ESIGRETURN;
    676 
    677 badframe:
    678     unlock_user_struct(frame, frame_addr, 0);
    679     force_sig(TARGET_SIGSEGV);
    680     return -QEMU_ESIGRETURN;
    681 }
    682 #endif
    683 
    684 long do_rt_sigreturn(CPUX86State *env)
    685 {
    686     abi_ulong frame_addr;
    687     struct rt_sigframe *frame;
    688     sigset_t set;
    689 
    690     frame_addr = env->regs[R_ESP] - sizeof(abi_ulong);
    691     trace_user_do_rt_sigreturn(env, frame_addr);
    692     if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))
    693         goto badframe;
    694     target_to_host_sigset(&set, &frame->uc.tuc_sigmask);
    695     set_sigmask(&set);
    696 
    697     if (restore_sigcontext(env, &frame->uc.tuc_mcontext)) {
    698         goto badframe;
    699     }
    700 
    701     target_restore_altstack(&frame->uc.tuc_stack, env);
    702 
    703     unlock_user_struct(frame, frame_addr, 0);
    704     return -QEMU_ESIGRETURN;
    705 
    706 badframe:
    707     unlock_user_struct(frame, frame_addr, 0);
    708     force_sig(TARGET_SIGSEGV);
    709     return -QEMU_ESIGRETURN;
    710 }
    711 
    712 #ifndef TARGET_X86_64
    713 void setup_sigtramp(abi_ulong sigtramp_page)
    714 {
    715     uint16_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 2 * 8, 0);
    716     assert(tramp != NULL);
    717 
    718     default_sigreturn = sigtramp_page;
    719     install_sigtramp(tramp);
    720 
    721     default_rt_sigreturn = sigtramp_page + 8;
    722     install_rt_sigtramp(tramp + 8);
    723 
    724     unlock_user(tramp, sigtramp_page, 2 * 8);
    725 }
    726 #endif