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      1 
      2 /*--------------------------------------------------------------------*/
      3 /*--- Create/destroy signal delivery frames.                       ---*/
      4 /*---                                       sigframe-amd64-linux.c ---*/
      5 /*--------------------------------------------------------------------*/
      6 
      7 /*
      8    This file is part of Valgrind, a dynamic binary instrumentation
      9    framework.
     10 
     11    Copyright (C) 2000-2011 Nicholas Nethercote
     12       njn (at) valgrind.org
     13 
     14    This program is free software; you can redistribute it and/or
     15    modify it under the terms of the GNU General Public License as
     16    published by the Free Software Foundation; either version 2 of the
     17    License, or (at your option) any later version.
     18 
     19    This program is distributed in the hope that it will be useful, but
     20    WITHOUT ANY WARRANTY; without even the implied warranty of
     21    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     22    General Public License for more details.
     23 
     24    You should have received a copy of the GNU General Public License
     25    along with this program; if not, write to the Free Software
     26    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
     27    02111-1307, USA.
     28 
     29    The GNU General Public License is contained in the file COPYING.
     30 */
     31 
     32 #if defined(VGP_amd64_linux)
     33 
     34 #include "pub_core_basics.h"
     35 #include "pub_core_vki.h"
     36 #include "pub_core_libcsetjmp.h"    // to keep _threadstate.h happy
     37 #include "pub_core_threadstate.h"
     38 #include "pub_core_aspacemgr.h"
     39 #include "pub_core_libcbase.h"
     40 #include "pub_core_libcassert.h"
     41 #include "pub_core_libcprint.h"
     42 #include "pub_core_machine.h"
     43 #include "pub_core_options.h"
     44 #include "pub_core_signals.h"
     45 #include "pub_core_tooliface.h"
     46 #include "pub_core_trampoline.h"
     47 #include "pub_core_sigframe.h"   /* self */
     48 
     49 /* This module creates and removes signal frames for signal deliveries
     50    on amd64-linux.
     51 
     52    Note, this file contains kernel-specific knowledge in the form of
     53    'struct rt_sigframe'.  How does that relate to the vki kernel
     54    interface stuff?
     55 
     56    A 'struct rtsigframe' is pushed onto the client's stack.  This
     57    contains a subsidiary vki_ucontext.  That holds the vcpu's state
     58    across the signal, so that the sighandler can mess with the vcpu
     59    state if it really wants.
     60 
     61    FIXME: sigcontexting is basically broken for the moment.  When
     62    delivering a signal, the integer registers and %rflags are
     63    correctly written into the sigcontext, however the FP and SSE state
     64    is not.  When returning from a signal, only the integer registers
     65    are restored from the sigcontext; the rest of the CPU state is
     66    restored to what it was before the signal.
     67 
     68    This will be fixed.
     69 */
     70 
     71 
     72 /*------------------------------------------------------------*/
     73 /*--- Signal frame layouts                                 ---*/
     74 /*------------------------------------------------------------*/
     75 
     76 // A structure in which to save the application's registers
     77 // during the execution of signal handlers.
     78 
     79 // In theory, so long as we get the arguments to the handler function
     80 // right, it doesn't matter what the exact layout of the rest of the
     81 // frame is.  Unfortunately, things like gcc's exception unwinding
     82 // make assumptions about the locations of various parts of the frame,
     83 // so we need to duplicate it exactly.
     84 
     85 /* Valgrind-specific parts of the signal frame */
     86 struct vg_sigframe
     87 {
     88    /* Sanity check word. */
     89    UInt magicPI;
     90 
     91    UInt handlerflags;	/* flags for signal handler */
     92 
     93 
     94    /* Safely-saved version of sigNo, as described above. */
     95    Int  sigNo_private;
     96 
     97    /* XXX This is wrong.  Surely we should store the shadow values
     98       into the shadow memory behind the actual values? */
     99    VexGuestAMD64State vex_shadow1;
    100    VexGuestAMD64State vex_shadow2;
    101 
    102    /* HACK ALERT */
    103    VexGuestAMD64State vex;
    104    /* end HACK ALERT */
    105 
    106    /* saved signal mask to be restored when handler returns */
    107    vki_sigset_t	mask;
    108 
    109    /* Sanity check word.  Is the highest-addressed word; do not
    110       move!*/
    111    UInt magicE;
    112 };
    113 
    114 struct rt_sigframe
    115 {
    116    /* Sig handler's return address */
    117    Addr retaddr;
    118 
    119    /* ucontext */
    120    struct vki_ucontext uContext;
    121 
    122    /* siginfo */
    123    vki_siginfo_t sigInfo;
    124    struct _vki_fpstate fpstate;
    125 
    126    struct vg_sigframe vg;
    127 };
    128 
    129 
    130 //:: /*------------------------------------------------------------*/
    131 //:: /*--- Signal operations                                    ---*/
    132 //:: /*------------------------------------------------------------*/
    133 //::
    134 //:: /*
    135 //::    Great gobs of FP state conversion taken wholesale from
    136 //::    linux/arch/i386/kernel/i387.c
    137 //::  */
    138 //::
    139 //:: /*
    140 //::  * FXSR floating point environment conversions.
    141 //::  */
    142 //:: #define X86_FXSR_MAGIC		0x0000
    143 //::
    144 //:: /*
    145 //::  * FPU tag word conversions.
    146 //::  */
    147 //::
    148 //:: static inline unsigned short twd_i387_to_fxsr( unsigned short twd )
    149 //:: {
    150 //::    unsigned int tmp; /* to avoid 16 bit prefixes in the code */
    151 //::
    152 //::    /* Transform each pair of bits into 01 (valid) or 00 (empty) */
    153 //::    tmp = ~twd;
    154 //::    tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */
    155 //::    /* and move the valid bits to the lower byte. */
    156 //::    tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */
    157 //::    tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */
    158 //::    tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */
    159 //::    return tmp;
    160 //:: }
    161 //::
    162 //:: static unsigned long twd_fxsr_to_i387( const struct i387_fxsave_struct *fxsave )
    163 //:: {
    164 //::    struct _vki_fpxreg *st = NULL;
    165 //::    unsigned long twd = (unsigned long) fxsave->twd;
    166 //::    unsigned long tag;
    167 //::    unsigned long ret = 0xffff0000u;
    168 //::    int i;
    169 //::
    170 //:: #define FPREG_ADDR(f, n)	((char *)&(f)->st_space + (n) * 16);
    171 //::
    172 //::    for ( i = 0 ; i < 8 ; i++ ) {
    173 //::       if ( twd & 0x1 ) {
    174 //:: 	 st = (struct _vki_fpxreg *) FPREG_ADDR( fxsave, i );
    175 //::
    176 //:: 	 switch ( st->exponent & 0x7fff ) {
    177 //:: 	 case 0x7fff:
    178 //:: 	    tag = 2;		/* Special */
    179 //:: 	    break;
    180 //:: 	 case 0x0000:
    181 //:: 	    if ( !st->significand[0] &&
    182 //:: 		 !st->significand[1] &&
    183 //:: 		 !st->significand[2] &&
    184 //:: 		 !st->significand[3] ) {
    185 //:: 	       tag = 1;	/* Zero */
    186 //:: 	    } else {
    187 //:: 	       tag = 2;	/* Special */
    188 //:: 	    }
    189 //:: 	    break;
    190 //:: 	 default:
    191 //:: 	    if ( st->significand[3] & 0x8000 ) {
    192 //:: 	       tag = 0;	/* Valid */
    193 //:: 	    } else {
    194 //:: 	       tag = 2;	/* Special */
    195 //:: 	    }
    196 //:: 	    break;
    197 //:: 	 }
    198 //::       } else {
    199 //:: 	 tag = 3;			/* Empty */
    200 //::       }
    201 //::       ret |= (tag << (2 * i));
    202 //::       twd = twd >> 1;
    203 //::    }
    204 //::    return ret;
    205 //:: }
    206 //::
    207 //:: static void convert_fxsr_to_user( struct _vki_fpstate *buf,
    208 //:: 				  const struct i387_fxsave_struct *fxsave )
    209 //:: {
    210 //::    unsigned long env[7];
    211 //::    struct _vki_fpreg *to;
    212 //::    struct _vki_fpxreg *from;
    213 //::    int i;
    214 //::
    215 //::    env[0] = (unsigned long)fxsave->cwd | 0xffff0000ul;
    216 //::    env[1] = (unsigned long)fxsave->swd | 0xffff0000ul;
    217 //::    env[2] = twd_fxsr_to_i387(fxsave);
    218 //::    env[3] = fxsave->fip;
    219 //::    env[4] = fxsave->fcs | ((unsigned long)fxsave->fop << 16);
    220 //::    env[5] = fxsave->foo;
    221 //::    env[6] = fxsave->fos;
    222 //::
    223 //::    VG_(memcpy)(buf, env, 7 * sizeof(unsigned long));
    224 //::
    225 //::    to = &buf->_st[0];
    226 //::    from = (struct _vki_fpxreg *) &fxsave->st_space[0];
    227 //::    for ( i = 0 ; i < 8 ; i++, to++, from++ ) {
    228 //::       unsigned long __user *t = (unsigned long __user *)to;
    229 //::       unsigned long *f = (unsigned long *)from;
    230 //::
    231 //::       t[0] = f[0];
    232 //::       t[1] = f[1];
    233 //::       to->exponent = from->exponent;
    234 //::    }
    235 //:: }
    236 //::
    237 //:: static void convert_fxsr_from_user( struct i387_fxsave_struct *fxsave,
    238 //:: 				    const struct _vki_fpstate *buf )
    239 //:: {
    240 //::    unsigned long env[7];
    241 //::    struct _vki_fpxreg *to;
    242 //::    const struct _vki_fpreg *from;
    243 //::    int i;
    244 //::
    245 //::    VG_(memcpy)(env, buf, 7 * sizeof(long));
    246 //::
    247 //::    fxsave->cwd = (unsigned short)(env[0] & 0xffff);
    248 //::    fxsave->swd = (unsigned short)(env[1] & 0xffff);
    249 //::    fxsave->twd = twd_i387_to_fxsr((unsigned short)(env[2] & 0xffff));
    250 //::    fxsave->fip = env[3];
    251 //::    fxsave->fop = (unsigned short)((env[4] & 0xffff0000ul) >> 16);
    252 //::    fxsave->fcs = (env[4] & 0xffff);
    253 //::    fxsave->foo = env[5];
    254 //::    fxsave->fos = env[6];
    255 //::
    256 //::    to = (struct _vki_fpxreg *) &fxsave->st_space[0];
    257 //::    from = &buf->_st[0];
    258 //::    for ( i = 0 ; i < 8 ; i++, to++, from++ ) {
    259 //::       unsigned long *t = (unsigned long *)to;
    260 //::       unsigned long __user *f = (unsigned long __user *)from;
    261 //::
    262 //::       t[0] = f[0];
    263 //::       t[1] = f[1];
    264 //::       to->exponent = from->exponent;
    265 //::    }
    266 //:: }
    267 //::
    268 //:: static inline void save_i387_fsave( arch_thread_t *regs, struct _vki_fpstate *buf )
    269 //:: {
    270 //::    struct i387_fsave_struct *fs = &regs->m_sse.fsave;
    271 //::
    272 //::    fs->status = fs->swd;
    273 //::    VG_(memcpy)(buf, fs, sizeof(*fs));
    274 //:: }
    275 //::
    276 //:: static void save_i387_fxsave( arch_thread_t *regs, struct _vki_fpstate *buf )
    277 //:: {
    278 //::    const struct i387_fxsave_struct *fx = &regs->m_sse.fxsave;
    279 //::    convert_fxsr_to_user( buf, fx );
    280 //::
    281 //::    buf->status = fx->swd;
    282 //::    buf->magic = X86_FXSR_MAGIC;
    283 //::    VG_(memcpy)(buf->_fxsr_env, fx, sizeof(struct i387_fxsave_struct));
    284 //:: }
    285 //::
    286 //:: static void save_i387( arch_thread_t *regs, struct _vki_fpstate *buf )
    287 //:: {
    288 //::    if ( VG_(have_ssestate) )
    289 //::       save_i387_fxsave( regs, buf );
    290 //::    else
    291 //::       save_i387_fsave( regs, buf );
    292 //:: }
    293 //::
    294 //:: static inline void restore_i387_fsave( arch_thread_t *regs, const struct _vki_fpstate __user *buf )
    295 //:: {
    296 //::    VG_(memcpy)( &regs->m_sse.fsave, buf, sizeof(struct i387_fsave_struct) );
    297 //:: }
    298 //::
    299 //:: static void restore_i387_fxsave( arch_thread_t *regs, const struct _vki_fpstate __user *buf )
    300 //:: {
    301 //::    VG_(memcpy)(&regs->m_sse.fxsave, &buf->_fxsr_env[0],
    302 //:: 	       sizeof(struct i387_fxsave_struct) );
    303 //::    /* mxcsr reserved bits must be masked to zero for security reasons */
    304 //::    regs->m_sse.fxsave.mxcsr &= 0xffbf;
    305 //::    convert_fxsr_from_user( &regs->m_sse.fxsave, buf );
    306 //:: }
    307 //::
    308 //:: static void restore_i387( arch_thread_t *regs, const struct _vki_fpstate __user *buf )
    309 //:: {
    310 //::    if ( VG_(have_ssestate) ) {
    311 //::       restore_i387_fxsave( regs, buf );
    312 //::    } else {
    313 //::       restore_i387_fsave( regs, buf );
    314 //::    }
    315 //:: }
    316 
    317 
    318 /*------------------------------------------------------------*/
    319 /*--- Creating signal frames                               ---*/
    320 /*------------------------------------------------------------*/
    321 
    322 /* Create a plausible-looking sigcontext from the thread's
    323    Vex guest state.  NOTE: does not fill in the FP or SSE
    324    bits of sigcontext at the moment.
    325 */
    326 static
    327 void synth_ucontext(ThreadId tid, const vki_siginfo_t *si,
    328                     UWord trapno, UWord err, const vki_sigset_t *set,
    329                     struct vki_ucontext *uc, struct _vki_fpstate *fpstate)
    330 {
    331    ThreadState *tst = VG_(get_ThreadState)(tid);
    332    struct vki_sigcontext *sc = &uc->uc_mcontext;
    333 
    334    VG_(memset)(uc, 0, sizeof(*uc));
    335 
    336    uc->uc_flags = 0;
    337    uc->uc_link = 0;
    338    uc->uc_sigmask = *set;
    339    uc->uc_stack = tst->altstack;
    340    sc->fpstate = fpstate;
    341 
    342    // FIXME: save_i387(&tst->arch, fpstate);
    343 
    344 #  define SC2(reg,REG)  sc->reg = tst->arch.vex.guest_##REG
    345    SC2(r8,R8);
    346    SC2(r9,R9);
    347    SC2(r10,R10);
    348    SC2(r11,R11);
    349    SC2(r12,R12);
    350    SC2(r13,R13);
    351    SC2(r14,R14);
    352    SC2(r15,R15);
    353    SC2(rdi,RDI);
    354    SC2(rsi,RSI);
    355    SC2(rbp,RBP);
    356    SC2(rbx,RBX);
    357    SC2(rdx,RDX);
    358    SC2(rax,RAX);
    359    SC2(rcx,RCX);
    360    SC2(rsp,RSP);
    361 
    362    SC2(rip,RIP);
    363    sc->eflags = LibVEX_GuestAMD64_get_rflags(&tst->arch.vex);
    364    // FIXME: SC2(cs,CS);
    365    // FIXME: SC2(gs,GS);
    366    // FIXME: SC2(fs,FS);
    367    sc->trapno = trapno;
    368    sc->err = err;
    369 #  undef SC2
    370 
    371    sc->cr2 = (UWord)si->_sifields._sigfault._addr;
    372 }
    373 
    374 
    375 /* Extend the stack segment downwards if needed so as to ensure the
    376    new signal frames are mapped to something.  Return a Bool
    377    indicating whether or not the operation was successful.
    378 */
    379 static Bool extend ( ThreadState *tst, Addr addr, SizeT size )
    380 {
    381    ThreadId        tid = tst->tid;
    382    NSegment const* stackseg = NULL;
    383 
    384    if (VG_(extend_stack)(addr, tst->client_stack_szB)) {
    385       stackseg = VG_(am_find_nsegment)(addr);
    386       if (0 && stackseg)
    387 	 VG_(printf)("frame=%#lx seg=%#lx-%#lx\n",
    388 		     addr, stackseg->start, stackseg->end);
    389    }
    390 
    391    if (stackseg == NULL || !stackseg->hasR || !stackseg->hasW) {
    392       VG_(message)(
    393          Vg_UserMsg,
    394          "Can't extend stack to %#lx during signal delivery for thread %d:\n",
    395          addr, tid);
    396       if (stackseg == NULL)
    397          VG_(message)(Vg_UserMsg, "  no stack segment\n");
    398       else
    399          VG_(message)(Vg_UserMsg, "  too small or bad protection modes\n");
    400 
    401       /* set SIGSEGV to default handler */
    402       VG_(set_default_handler)(VKI_SIGSEGV);
    403       VG_(synth_fault_mapping)(tid, addr);
    404 
    405       /* The whole process should be about to die, since the default
    406 	 action of SIGSEGV to kill the whole process. */
    407       return False;
    408    }
    409 
    410    /* For tracking memory events, indicate the entire frame has been
    411       allocated. */
    412    VG_TRACK( new_mem_stack_signal, addr - VG_STACK_REDZONE_SZB,
    413              size + VG_STACK_REDZONE_SZB, tid );
    414 
    415    return True;
    416 }
    417 
    418 
    419 /* Build the Valgrind-specific part of a signal frame. */
    420 
    421 static void build_vg_sigframe(struct vg_sigframe *frame,
    422 			      ThreadState *tst,
    423 			      const vki_sigset_t *mask,
    424 			      UInt flags,
    425 			      Int sigNo)
    426 {
    427    frame->sigNo_private = sigNo;
    428    frame->magicPI       = 0x31415927;
    429    frame->vex_shadow1   = tst->arch.vex_shadow1;
    430    frame->vex_shadow2   = tst->arch.vex_shadow2;
    431    /* HACK ALERT */
    432    frame->vex           = tst->arch.vex;
    433    /* end HACK ALERT */
    434    frame->mask          = tst->sig_mask;
    435    frame->handlerflags  = flags;
    436    frame->magicE        = 0x27182818;
    437 }
    438 
    439 
    440 static Addr build_rt_sigframe(ThreadState *tst,
    441 			      Addr rsp_top_of_frame,
    442 			      const vki_siginfo_t *siginfo,
    443                               const struct vki_ucontext *siguc,
    444 			      void *handler, UInt flags,
    445 			      const vki_sigset_t *mask,
    446 			      void *restorer)
    447 {
    448    struct rt_sigframe *frame;
    449    Addr rsp = rsp_top_of_frame;
    450    Int	sigNo = siginfo->si_signo;
    451    UWord trapno;
    452    UWord err;
    453 
    454    rsp -= sizeof(*frame);
    455    rsp = VG_ROUNDDN(rsp, 16);
    456    frame = (struct rt_sigframe *)rsp;
    457 
    458    if (!extend(tst, rsp, sizeof(*frame)))
    459       return rsp_top_of_frame;
    460 
    461    /* retaddr, siginfo, uContext fields are to be written */
    462    VG_TRACK( pre_mem_write, Vg_CoreSignal, tst->tid, "rt signal handler frame",
    463 	     rsp, offsetof(struct rt_sigframe, vg) );
    464 
    465    if (flags & VKI_SA_RESTORER)
    466       frame->retaddr = (Addr)restorer;
    467    else
    468       frame->retaddr = (Addr)&VG_(amd64_linux_SUBST_FOR_rt_sigreturn);
    469 
    470    if (siguc) {
    471       trapno = siguc->uc_mcontext.trapno;
    472       err = siguc->uc_mcontext.err;
    473    } else {
    474       trapno = 0;
    475       err = 0;
    476    }
    477 
    478    VG_(memcpy)(&frame->sigInfo, siginfo, sizeof(vki_siginfo_t));
    479 
    480    /* SIGILL defines addr to be the faulting address */
    481    if (sigNo == VKI_SIGILL && siginfo->si_code > 0)
    482       frame->sigInfo._sifields._sigfault._addr
    483          = (void*)tst->arch.vex.guest_RIP;
    484 
    485    synth_ucontext(tst->tid, siginfo, trapno, err, mask,
    486                   &frame->uContext, &frame->fpstate);
    487 
    488    VG_TRACK( post_mem_write,  Vg_CoreSignal, tst->tid,
    489              rsp, offsetof(struct rt_sigframe, vg) );
    490 
    491    build_vg_sigframe(&frame->vg, tst, mask, flags, sigNo);
    492 
    493    return rsp;
    494 }
    495 
    496 
    497 void VG_(sigframe_create)( ThreadId tid,
    498                             Addr rsp_top_of_frame,
    499                             const vki_siginfo_t *siginfo,
    500                             const struct vki_ucontext *siguc,
    501                             void *handler,
    502                             UInt flags,
    503                             const vki_sigset_t *mask,
    504                             void *restorer )
    505 {
    506    Addr rsp;
    507    struct rt_sigframe *frame;
    508    ThreadState* tst = VG_(get_ThreadState)(tid);
    509 
    510    rsp = build_rt_sigframe(tst, rsp_top_of_frame, siginfo, siguc,
    511                                 handler, flags, mask, restorer);
    512    frame = (struct rt_sigframe *)rsp;
    513 
    514    /* Set the thread so it will next run the handler. */
    515    /* tst->m_rsp  = rsp;  also notify the tool we've updated RSP */
    516    VG_(set_SP)(tid, rsp);
    517    VG_TRACK( post_reg_write, Vg_CoreSignal, tid, VG_O_STACK_PTR, sizeof(Addr));
    518 
    519    //VG_(printf)("handler = %p\n", handler);
    520    tst->arch.vex.guest_RIP = (Addr) handler;
    521    tst->arch.vex.guest_RDI = (ULong) siginfo->si_signo;
    522    tst->arch.vex.guest_RSI = (Addr) &frame->sigInfo;
    523    tst->arch.vex.guest_RDX = (Addr) &frame->uContext;
    524    /* This thread needs to be marked runnable, but we leave that the
    525       caller to do. */
    526 
    527    if (0)
    528       VG_(printf)("pushed signal frame; %%RSP now = %#lx, "
    529                   "next %%RIP = %#llx, status=%d\n",
    530 		  rsp, tst->arch.vex.guest_RIP, tst->status);
    531 }
    532 
    533 
    534 /*------------------------------------------------------------*/
    535 /*--- Destroying signal frames                             ---*/
    536 /*------------------------------------------------------------*/
    537 
    538 /* Return False and don't do anything, just set the client to take a
    539    segfault, if it looks like the frame is corrupted. */
    540 static
    541 Bool restore_vg_sigframe ( ThreadState *tst,
    542                            struct vg_sigframe *frame, Int *sigNo )
    543 {
    544    if (frame->magicPI != 0x31415927 ||
    545        frame->magicE  != 0x27182818) {
    546       VG_(message)(Vg_UserMsg, "Thread %d return signal frame "
    547                                "corrupted.  Killing process.\n",
    548 		   tst->tid);
    549       VG_(set_default_handler)(VKI_SIGSEGV);
    550       VG_(synth_fault)(tst->tid);
    551       *sigNo = VKI_SIGSEGV;
    552       return False;
    553    }
    554    tst->sig_mask         = frame->mask;
    555    tst->tmp_sig_mask     = frame->mask;
    556    tst->arch.vex_shadow1 = frame->vex_shadow1;
    557    tst->arch.vex_shadow2 = frame->vex_shadow2;
    558    /* HACK ALERT */
    559    tst->arch.vex         = frame->vex;
    560    /* end HACK ALERT */
    561    *sigNo                = frame->sigNo_private;
    562    return True;
    563 }
    564 
    565 static
    566 void restore_sigcontext( ThreadState *tst,
    567                          struct vki_sigcontext *sc,
    568                          struct _vki_fpstate *fpstate )
    569 {
    570    tst->arch.vex.guest_RAX     = sc->rax;
    571    tst->arch.vex.guest_RCX     = sc->rcx;
    572    tst->arch.vex.guest_RDX     = sc->rdx;
    573    tst->arch.vex.guest_RBX     = sc->rbx;
    574    tst->arch.vex.guest_RBP     = sc->rbp;
    575    tst->arch.vex.guest_RSP     = sc->rsp;
    576    tst->arch.vex.guest_RSI     = sc->rsi;
    577    tst->arch.vex.guest_RDI     = sc->rdi;
    578    tst->arch.vex.guest_R8      = sc->r8;
    579    tst->arch.vex.guest_R9      = sc->r9;
    580    tst->arch.vex.guest_R10     = sc->r10;
    581    tst->arch.vex.guest_R11     = sc->r11;
    582    tst->arch.vex.guest_R12     = sc->r12;
    583    tst->arch.vex.guest_R13     = sc->r13;
    584    tst->arch.vex.guest_R14     = sc->r14;
    585    tst->arch.vex.guest_R15     = sc->r15;
    586 //::    tst->arch.vex.guest_rflags  = sc->rflags;
    587    tst->arch.vex.guest_RIP     = sc->rip;
    588 
    589 //::    tst->arch.vex.guest_CS      = sc->cs;
    590 //::    tst->arch.vex.guest_FS      = sc->fs;
    591 //::    tst->arch.vex.guest_GS      = sc->gs;
    592 
    593 //::    restore_i387(&tst->arch, fpstate);
    594 }
    595 
    596 
    597 static
    598 SizeT restore_rt_sigframe ( ThreadState *tst,
    599                             struct rt_sigframe *frame, Int *sigNo )
    600 {
    601    if (restore_vg_sigframe(tst, &frame->vg, sigNo))
    602       restore_sigcontext(tst, &frame->uContext.uc_mcontext, &frame->fpstate);
    603 
    604    return sizeof(*frame);
    605 }
    606 
    607 
    608 void VG_(sigframe_destroy)( ThreadId tid, Bool isRT )
    609 {
    610    Addr          rsp;
    611    ThreadState*  tst;
    612    SizeT	 size;
    613    Int		 sigNo;
    614 
    615    vg_assert(isRT);
    616 
    617    tst = VG_(get_ThreadState)(tid);
    618 
    619    /* Correctly reestablish the frame base address. */
    620    rsp   = tst->arch.vex.guest_RSP;
    621 
    622    size = restore_rt_sigframe(tst, (struct rt_sigframe *)rsp, &sigNo);
    623 
    624    VG_TRACK( die_mem_stack_signal, rsp - VG_STACK_REDZONE_SZB,
    625              size + VG_STACK_REDZONE_SZB );
    626 
    627    if (VG_(clo_trace_signals))
    628       VG_(message)(
    629          Vg_DebugMsg,
    630          "VG_(signal_return) (thread %d): isRT=%d valid magic; RIP=%#llx\n",
    631          tid, isRT, tst->arch.vex.guest_RIP);
    632 
    633    /* tell the tools */
    634    VG_TRACK( post_deliver_signal, tid, sigNo );
    635 }
    636 
    637 #endif // defined(VGP_amd64_linux)
    638 
    639 /*--------------------------------------------------------------------*/
    640 /*--- end                                                          ---*/
    641 /*--------------------------------------------------------------------*/
    642