1
2/*--------------------------------------------------------------------*/
3/*--- Create/destroy signal delivery frames.                       ---*/
4/*---                                         sigframe-x86-linux.c ---*/
5/*--------------------------------------------------------------------*/
6
7/*
8   This file is part of Valgrind, a dynamic binary instrumentation
9   framework.
10
11   Copyright (C) 2000-2013 Nicholas Nethercote
12      njn@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_x86_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" /* find_segment */
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
50/* This module creates and removes signal frames for signal deliveries
51   on x86-linux.
52
53   Note, this file contains kernel-specific knowledge in the form of
54   'struct sigframe' and 'struct rt_sigframe'.  How does that relate
55   to the vki kernel interface stuff?
56
57   Either a 'struct sigframe' or a 'struct rtsigframe' is pushed
58   onto the client's stack.  This contains a subsidiary
59   vki_ucontext.  That holds the vcpu's state across the signal,
60   so that the sighandler can mess with the vcpu state if it
61   really wants.
62
63   FIXME: sigcontexting is basically broken for the moment.  When
64   delivering a signal, the integer registers and %eflags are
65   correctly written into the sigcontext, however the FP and SSE state
66   is not.  When returning from a signal, only the integer registers
67   are restored from the sigcontext; the rest of the CPU state is
68   restored to what it was before the signal.
69
70   This will be fixed.
71*/
72
73
74/*------------------------------------------------------------*/
75/*--- Signal frame layouts                                 ---*/
76/*------------------------------------------------------------*/
77
78// A structure in which to save the application's registers
79// during the execution of signal handlers.
80
81// Linux has 2 signal frame structures: one for normal signal
82// deliveries, and one for SA_SIGINFO deliveries (also known as RT
83// signals).
84//
85// In theory, so long as we get the arguments to the handler function
86// right, it doesn't matter what the exact layout of the rest of the
87// frame is.  Unfortunately, things like gcc's exception unwinding
88// make assumptions about the locations of various parts of the frame,
89// so we need to duplicate it exactly.
90
91/* Valgrind-specific parts of the signal frame */
92struct vg_sigframe
93{
94   /* Sanity check word. */
95   UInt magicPI;
96
97   UInt handlerflags;	/* flags for signal handler */
98
99
100   /* Safely-saved version of sigNo, as described above. */
101   Int  sigNo_private;
102
103   /* XXX This is wrong.  Surely we should store the shadow values
104      into the shadow memory behind the actual values? */
105   VexGuestX86State vex_shadow1;
106   VexGuestX86State vex_shadow2;
107
108   /* HACK ALERT */
109   VexGuestX86State vex;
110   /* end HACK ALERT */
111
112   /* saved signal mask to be restored when handler returns */
113   vki_sigset_t	mask;
114
115   /* Sanity check word.  Is the highest-addressed word; do not
116      move!*/
117   UInt magicE;
118};
119
120struct sigframe
121{
122   /* Sig handler's return address */
123   Addr retaddr;
124   Int  sigNo;
125
126   struct vki_sigcontext sigContext;
127   struct _vki_fpstate fpstate;
128
129   struct vg_sigframe vg;
130};
131
132struct rt_sigframe
133{
134   /* Sig handler's return address */
135   Addr retaddr;
136   Int  sigNo;
137
138   /* ptr to siginfo_t. */
139   Addr psigInfo;
140
141   /* ptr to ucontext */
142   Addr puContext;
143   /* pointed to by psigInfo */
144   vki_siginfo_t sigInfo;
145
146   /* pointed to by puContext */
147   struct vki_ucontext uContext;
148   struct _vki_fpstate fpstate;
149
150   struct vg_sigframe vg;
151};
152
153
154//:: /*------------------------------------------------------------*/
155//:: /*--- Signal operations                                    ---*/
156//:: /*------------------------------------------------------------*/
157//::
158//:: /*
159//::    Great gobs of FP state conversion taken wholesale from
160//::    linux/arch/i386/kernel/i387.c
161//::  */
162//::
163//:: /*
164//::  * FXSR floating point environment conversions.
165//::  */
166//:: #define X86_FXSR_MAGIC		0x0000
167//::
168//:: /*
169//::  * FPU tag word conversions.
170//::  */
171//::
172//:: static inline unsigned short twd_i387_to_fxsr( unsigned short twd )
173//:: {
174//::    unsigned int tmp; /* to avoid 16 bit prefixes in the code */
175//::
176//::    /* Transform each pair of bits into 01 (valid) or 00 (empty) */
177//::    tmp = ~twd;
178//::    tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */
179//::    /* and move the valid bits to the lower byte. */
180//::    tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */
181//::    tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */
182//::    tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */
183//::    return tmp;
184//:: }
185//::
186//:: static unsigned long twd_fxsr_to_i387( const struct i387_fxsave_struct *fxsave )
187//:: {
188//::    struct _vki_fpxreg *st = NULL;
189//::    unsigned long twd = (unsigned long) fxsave->twd;
190//::    unsigned long tag;
191//::    unsigned long ret = 0xffff0000u;
192//::    int i;
193//::
194//:: #define FPREG_ADDR(f, n)	((char *)&(f)->st_space + (n) * 16);
195//::
196//::    for ( i = 0 ; i < 8 ; i++ ) {
197//::       if ( twd & 0x1 ) {
198//:: 	 st = (struct _vki_fpxreg *) FPREG_ADDR( fxsave, i );
199//::
200//:: 	 switch ( st->exponent & 0x7fff ) {
201//:: 	 case 0x7fff:
202//:: 	    tag = 2;		/* Special */
203//:: 	    break;
204//:: 	 case 0x0000:
205//:: 	    if ( !st->significand[0] &&
206//:: 		 !st->significand[1] &&
207//:: 		 !st->significand[2] &&
208//:: 		 !st->significand[3] ) {
209//:: 	       tag = 1;	/* Zero */
210//:: 	    } else {
211//:: 	       tag = 2;	/* Special */
212//:: 	    }
213//:: 	    break;
214//:: 	 default:
215//:: 	    if ( st->significand[3] & 0x8000 ) {
216//:: 	       tag = 0;	/* Valid */
217//:: 	    } else {
218//:: 	       tag = 2;	/* Special */
219//:: 	    }
220//:: 	    break;
221//:: 	 }
222//::       } else {
223//:: 	 tag = 3;			/* Empty */
224//::       }
225//::       ret |= (tag << (2 * i));
226//::       twd = twd >> 1;
227//::    }
228//::    return ret;
229//:: }
230//::
231//:: static void convert_fxsr_to_user( struct _vki_fpstate *buf,
232//:: 				  const struct i387_fxsave_struct *fxsave )
233//:: {
234//::    unsigned long env[7];
235//::    struct _vki_fpreg *to;
236//::    struct _vki_fpxreg *from;
237//::    int i;
238//::
239//::    env[0] = (unsigned long)fxsave->cwd | 0xffff0000ul;
240//::    env[1] = (unsigned long)fxsave->swd | 0xffff0000ul;
241//::    env[2] = twd_fxsr_to_i387(fxsave);
242//::    env[3] = fxsave->fip;
243//::    env[4] = fxsave->fcs | ((unsigned long)fxsave->fop << 16);
244//::    env[5] = fxsave->foo;
245//::    env[6] = fxsave->fos;
246//::
247//::    VG_(memcpy)(buf, env, 7 * sizeof(unsigned long));
248//::
249//::    to = &buf->_st[0];
250//::    from = (struct _vki_fpxreg *) &fxsave->st_space[0];
251//::    for ( i = 0 ; i < 8 ; i++, to++, from++ ) {
252//::       unsigned long __user *t = (unsigned long __user *)to;
253//::       unsigned long *f = (unsigned long *)from;
254//::
255//::       t[0] = f[0];
256//::       t[1] = f[1];
257//::       to->exponent = from->exponent;
258//::    }
259//:: }
260//::
261//:: static void convert_fxsr_from_user( struct i387_fxsave_struct *fxsave,
262//:: 				    const struct _vki_fpstate *buf )
263//:: {
264//::    unsigned long env[7];
265//::    struct _vki_fpxreg *to;
266//::    const struct _vki_fpreg *from;
267//::    int i;
268//::
269//::    VG_(memcpy)(env, buf, 7 * sizeof(long));
270//::
271//::    fxsave->cwd = (unsigned short)(env[0] & 0xffff);
272//::    fxsave->swd = (unsigned short)(env[1] & 0xffff);
273//::    fxsave->twd = twd_i387_to_fxsr((unsigned short)(env[2] & 0xffff));
274//::    fxsave->fip = env[3];
275//::    fxsave->fop = (unsigned short)((env[4] & 0xffff0000ul) >> 16);
276//::    fxsave->fcs = (env[4] & 0xffff);
277//::    fxsave->foo = env[5];
278//::    fxsave->fos = env[6];
279//::
280//::    to = (struct _vki_fpxreg *) &fxsave->st_space[0];
281//::    from = &buf->_st[0];
282//::    for ( i = 0 ; i < 8 ; i++, to++, from++ ) {
283//::       unsigned long *t = (unsigned long *)to;
284//::       unsigned long __user *f = (unsigned long __user *)from;
285//::
286//::       t[0] = f[0];
287//::       t[1] = f[1];
288//::       to->exponent = from->exponent;
289//::    }
290//:: }
291//::
292//:: static inline void save_i387_fsave( arch_thread_t *regs, struct _vki_fpstate *buf )
293//:: {
294//::    struct i387_fsave_struct *fs = &regs->m_sse.fsave;
295//::
296//::    fs->status = fs->swd;
297//::    VG_(memcpy)(buf, fs, sizeof(*fs));
298//:: }
299//::
300//:: static void save_i387_fxsave( arch_thread_t *regs, struct _vki_fpstate *buf )
301//:: {
302//::    const struct i387_fxsave_struct *fx = &regs->m_sse.fxsave;
303//::    convert_fxsr_to_user( buf, fx );
304//::
305//::    buf->status = fx->swd;
306//::    buf->magic = X86_FXSR_MAGIC;
307//::    VG_(memcpy)(buf->_fxsr_env, fx, sizeof(struct i387_fxsave_struct));
308//:: }
309//::
310//:: static void save_i387( arch_thread_t *regs, struct _vki_fpstate *buf )
311//:: {
312//::    if ( VG_(have_ssestate) )
313//::       save_i387_fxsave( regs, buf );
314//::    else
315//::       save_i387_fsave( regs, buf );
316//:: }
317//::
318//:: static inline void restore_i387_fsave( arch_thread_t *regs, const struct _vki_fpstate __user *buf )
319//:: {
320//::    VG_(memcpy)( &regs->m_sse.fsave, buf, sizeof(struct i387_fsave_struct) );
321//:: }
322//::
323//:: static void restore_i387_fxsave( arch_thread_t *regs, const struct _vki_fpstate __user *buf )
324//:: {
325//::    VG_(memcpy)(&regs->m_sse.fxsave, &buf->_fxsr_env[0],
326//:: 	       sizeof(struct i387_fxsave_struct) );
327//::    /* mxcsr reserved bits must be masked to zero for security reasons */
328//::    regs->m_sse.fxsave.mxcsr &= 0xffbf;
329//::    convert_fxsr_from_user( &regs->m_sse.fxsave, buf );
330//:: }
331//::
332//:: static void restore_i387( arch_thread_t *regs, const struct _vki_fpstate __user *buf )
333//:: {
334//::    if ( VG_(have_ssestate) ) {
335//::       restore_i387_fxsave( regs, buf );
336//::    } else {
337//::       restore_i387_fsave( regs, buf );
338//::    }
339//:: }
340
341
342/*------------------------------------------------------------*/
343/*--- Creating signal frames                               ---*/
344/*------------------------------------------------------------*/
345
346/* Create a plausible-looking sigcontext from the thread's
347   Vex guest state.  NOTE: does not fill in the FP or SSE
348   bits of sigcontext at the moment.
349*/
350static
351void synth_ucontext(ThreadId tid, const vki_siginfo_t *si,
352                    UWord trapno, UWord err, const vki_sigset_t *set,
353                    struct vki_ucontext *uc, struct _vki_fpstate *fpstate)
354{
355   ThreadState *tst = VG_(get_ThreadState)(tid);
356   struct vki_sigcontext *sc = &uc->uc_mcontext;
357
358   VG_(memset)(uc, 0, sizeof(*uc));
359
360   uc->uc_flags = 0;
361   uc->uc_link = 0;
362   uc->uc_sigmask = *set;
363   uc->uc_stack = tst->altstack;
364   sc->fpstate = fpstate;
365
366   // FIXME: save_i387(&tst->arch, fpstate);
367
368#  define SC2(reg,REG)  sc->reg = tst->arch.vex.guest_##REG
369   SC2(gs,GS);
370   SC2(fs,FS);
371   SC2(es,ES);
372   SC2(ds,DS);
373
374   SC2(edi,EDI);
375   SC2(esi,ESI);
376   SC2(ebp,EBP);
377   SC2(esp,ESP);
378   SC2(ebx,EBX);
379   SC2(edx,EDX);
380   SC2(ecx,ECX);
381   SC2(eax,EAX);
382
383   SC2(eip,EIP);
384   SC2(cs,CS);
385   sc->eflags = LibVEX_GuestX86_get_eflags(&tst->arch.vex);
386   SC2(ss,SS);
387   /* XXX esp_at_signal */
388   sc->trapno = trapno;
389   sc->err = err;
390#  undef SC2
391
392   sc->cr2 = (UInt)si->_sifields._sigfault._addr;
393}
394
395
396/* Extend the stack segment downwards if needed so as to ensure the
397   new signal frames are mapped to something.  Return a Bool
398   indicating whether or not the operation was successful.
399*/
400static Bool extend ( ThreadState *tst, Addr addr, SizeT size )
401{
402   ThreadId        tid = tst->tid;
403   NSegment const* stackseg = NULL;
404
405   if (VG_(extend_stack)(addr, tst->client_stack_szB)) {
406      stackseg = VG_(am_find_nsegment)(addr);
407      if (0 && stackseg)
408	 VG_(printf)("frame=%#lx seg=%#lx-%#lx\n",
409		     addr, stackseg->start, stackseg->end);
410   }
411
412   if (stackseg == NULL || !stackseg->hasR || !stackseg->hasW) {
413      VG_(message)(
414         Vg_UserMsg,
415         "Can't extend stack to %#lx during signal delivery for thread %d:\n",
416         addr, tid);
417      if (stackseg == NULL)
418         VG_(message)(Vg_UserMsg, "  no stack segment\n");
419      else
420         VG_(message)(Vg_UserMsg, "  too small or bad protection modes\n");
421
422      /* set SIGSEGV to default handler */
423      VG_(set_default_handler)(VKI_SIGSEGV);
424      VG_(synth_fault_mapping)(tid, addr);
425
426      /* The whole process should be about to die, since the default
427	 action of SIGSEGV to kill the whole process. */
428      return False;
429   }
430
431   /* For tracking memory events, indicate the entire frame has been
432      allocated. */
433   VG_TRACK( new_mem_stack_signal, addr - VG_STACK_REDZONE_SZB,
434             size + VG_STACK_REDZONE_SZB, tid );
435
436   return True;
437}
438
439
440/* Build the Valgrind-specific part of a signal frame. */
441
442static void build_vg_sigframe(struct vg_sigframe *frame,
443			      ThreadState *tst,
444			      UInt flags,
445			      Int sigNo)
446{
447   frame->sigNo_private = sigNo;
448   frame->magicPI       = 0x31415927;
449   frame->vex_shadow1   = tst->arch.vex_shadow1;
450   frame->vex_shadow2   = tst->arch.vex_shadow2;
451   /* HACK ALERT */
452   frame->vex           = tst->arch.vex;
453   /* end HACK ALERT */
454   frame->mask          = tst->sig_mask;
455   frame->handlerflags  = flags;
456   frame->magicE        = 0x27182818;
457}
458
459
460static Addr build_sigframe(ThreadState *tst,
461			   Addr esp_top_of_frame,
462			   const vki_siginfo_t *siginfo,
463                           const struct vki_ucontext *siguc,
464			   UInt flags,
465			   const vki_sigset_t *mask,
466			   void *restorer)
467{
468   struct sigframe *frame;
469   Addr esp = esp_top_of_frame;
470   Int	sigNo = siginfo->si_signo;
471   UWord trapno;
472   UWord err;
473   struct vki_ucontext uc;
474
475   vg_assert((flags & VKI_SA_SIGINFO) == 0);
476
477   esp -= sizeof(*frame);
478   esp = VG_ROUNDDN(esp, 16);
479   frame = (struct sigframe *)esp;
480
481   if (!extend(tst, esp, sizeof(*frame)))
482      return esp_top_of_frame;
483
484   /* retaddr, sigNo, siguContext fields are to be written */
485   VG_TRACK( pre_mem_write, Vg_CoreSignal, tst->tid, "signal handler frame",
486	     esp, offsetof(struct sigframe, vg) );
487
488   frame->sigNo = sigNo;
489
490   if (flags & VKI_SA_RESTORER)
491      frame->retaddr = (Addr)restorer;
492   else
493      frame->retaddr = (Addr)&VG_(x86_linux_SUBST_FOR_sigreturn);
494
495   if (siguc) {
496      trapno = siguc->uc_mcontext.trapno;
497      err = siguc->uc_mcontext.err;
498   } else {
499      trapno = 0;
500      err = 0;
501   }
502
503   synth_ucontext(tst->tid, siginfo, trapno, err, mask, &uc, &frame->fpstate);
504
505   VG_(memcpy)(&frame->sigContext, &uc.uc_mcontext,
506	       sizeof(struct vki_sigcontext));
507   frame->sigContext.oldmask = mask->sig[0];
508
509   VG_TRACK( post_mem_write, Vg_CoreSignal, tst->tid,
510             esp, offsetof(struct sigframe, vg) );
511
512   build_vg_sigframe(&frame->vg, tst, flags, sigNo);
513
514   return esp;
515}
516
517
518static Addr build_rt_sigframe(ThreadState *tst,
519			      Addr esp_top_of_frame,
520			      const vki_siginfo_t *siginfo,
521                              const struct vki_ucontext *siguc,
522			      UInt flags,
523			      const vki_sigset_t *mask,
524			      void *restorer)
525{
526   struct rt_sigframe *frame;
527   Addr esp = esp_top_of_frame;
528   Int	sigNo = siginfo->si_signo;
529   UWord trapno;
530   UWord err;
531
532   vg_assert((flags & VKI_SA_SIGINFO) != 0);
533
534   esp -= sizeof(*frame);
535   esp = VG_ROUNDDN(esp, 16);
536   frame = (struct rt_sigframe *)esp;
537
538   if (!extend(tst, esp, sizeof(*frame)))
539      return esp_top_of_frame;
540
541   /* retaddr, sigNo, pSiginfo, puContext fields are to be written */
542   VG_TRACK( pre_mem_write, Vg_CoreSignal, tst->tid, "rt signal handler frame",
543	     esp, offsetof(struct rt_sigframe, vg) );
544
545   frame->sigNo = sigNo;
546
547   if (flags & VKI_SA_RESTORER)
548      frame->retaddr = (Addr)restorer;
549   else
550      frame->retaddr = (Addr)&VG_(x86_linux_SUBST_FOR_rt_sigreturn);
551
552   if (siguc) {
553      trapno = siguc->uc_mcontext.trapno;
554      err = siguc->uc_mcontext.err;
555   } else {
556      trapno = 0;
557      err = 0;
558   }
559
560   frame->psigInfo = (Addr)&frame->sigInfo;
561   frame->puContext = (Addr)&frame->uContext;
562   VG_(memcpy)(&frame->sigInfo, siginfo, sizeof(vki_siginfo_t));
563
564   /* SIGILL defines addr to be the faulting address */
565   if (sigNo == VKI_SIGILL && siginfo->si_code > 0)
566      frame->sigInfo._sifields._sigfault._addr
567         = (void*)tst->arch.vex.guest_EIP;
568
569   synth_ucontext(tst->tid, siginfo, trapno, err, mask,
570                  &frame->uContext, &frame->fpstate);
571
572   VG_TRACK( post_mem_write,  Vg_CoreSignal, tst->tid,
573             esp, offsetof(struct rt_sigframe, vg) );
574
575   build_vg_sigframe(&frame->vg, tst, flags, sigNo);
576
577   return esp;
578}
579
580
581/* EXPORTED */
582void VG_(sigframe_create)( ThreadId tid,
583                           Addr esp_top_of_frame,
584                           const vki_siginfo_t *siginfo,
585                           const struct vki_ucontext *siguc,
586                           void *handler,
587                           UInt flags,
588                           const vki_sigset_t *mask,
589		           void *restorer )
590{
591   Addr		esp;
592   ThreadState* tst = VG_(get_ThreadState)(tid);
593
594   if (flags & VKI_SA_SIGINFO)
595      esp = build_rt_sigframe(tst, esp_top_of_frame, siginfo, siguc,
596                                   flags, mask, restorer);
597   else
598      esp = build_sigframe(tst, esp_top_of_frame, siginfo, siguc,
599                                flags, mask, restorer);
600
601   /* Set the thread so it will next run the handler. */
602   /* tst->m_esp  = esp;  also notify the tool we've updated ESP */
603   VG_(set_SP)(tid, esp);
604   VG_TRACK( post_reg_write, Vg_CoreSignal, tid, VG_O_STACK_PTR, sizeof(Addr));
605
606   //VG_(printf)("handler = %p\n", handler);
607   tst->arch.vex.guest_EIP = (Addr) handler;
608   /* This thread needs to be marked runnable, but we leave that the
609      caller to do. */
610
611   if (0)
612      VG_(printf)("pushed signal frame; %%ESP now = %#lx, "
613                  "next %%EIP = %#x, status=%d\n",
614		  esp, tst->arch.vex.guest_EIP, tst->status);
615}
616
617
618/*------------------------------------------------------------*/
619/*--- Destroying signal frames                             ---*/
620/*------------------------------------------------------------*/
621
622/* Return False and don't do anything, just set the client to take a
623   segfault, if it looks like the frame is corrupted. */
624static
625Bool restore_vg_sigframe ( ThreadState *tst,
626                           struct vg_sigframe *frame, Int *sigNo )
627{
628   if (frame->magicPI != 0x31415927 ||
629       frame->magicE  != 0x27182818) {
630      VG_(message)(Vg_UserMsg, "Thread %d return signal frame "
631                               "corrupted.  Killing process.\n",
632		   tst->tid);
633      VG_(set_default_handler)(VKI_SIGSEGV);
634      VG_(synth_fault)(tst->tid);
635      *sigNo = VKI_SIGSEGV;
636      return False;
637   }
638   tst->sig_mask         = frame->mask;
639   tst->tmp_sig_mask     = frame->mask;
640   tst->arch.vex_shadow1 = frame->vex_shadow1;
641   tst->arch.vex_shadow2 = frame->vex_shadow2;
642   /* HACK ALERT */
643   tst->arch.vex         = frame->vex;
644   /* end HACK ALERT */
645   *sigNo                = frame->sigNo_private;
646   return True;
647}
648
649static
650void restore_sigcontext( ThreadState *tst,
651                         struct vki_sigcontext *sc,
652                         struct _vki_fpstate *fpstate )
653{
654   tst->arch.vex.guest_EAX     = sc->eax;
655   tst->arch.vex.guest_ECX     = sc->ecx;
656   tst->arch.vex.guest_EDX     = sc->edx;
657   tst->arch.vex.guest_EBX     = sc->ebx;
658   tst->arch.vex.guest_EBP     = sc->ebp;
659   tst->arch.vex.guest_ESP     = sc->esp;
660   tst->arch.vex.guest_ESI     = sc->esi;
661   tst->arch.vex.guest_EDI     = sc->edi;
662//::    tst->arch.vex.guest_eflags  = sc->eflags;
663   tst->arch.vex.guest_EIP     = sc->eip;
664   tst->arch.vex.guest_CS      = sc->cs;
665   tst->arch.vex.guest_SS      = sc->ss;
666   tst->arch.vex.guest_DS      = sc->ds;
667   tst->arch.vex.guest_ES      = sc->es;
668   tst->arch.vex.guest_FS      = sc->fs;
669   tst->arch.vex.guest_GS      = sc->gs;
670
671//::    restore_i387(&tst->arch, fpstate);
672}
673
674
675static
676SizeT restore_sigframe ( ThreadState *tst,
677                         struct sigframe *frame, Int *sigNo )
678{
679   if (restore_vg_sigframe(tst, &frame->vg, sigNo))
680      restore_sigcontext(tst, &frame->sigContext, &frame->fpstate);
681
682   return sizeof(*frame);
683}
684
685static
686SizeT restore_rt_sigframe ( ThreadState *tst,
687                            struct rt_sigframe *frame, Int *sigNo )
688{
689   if (restore_vg_sigframe(tst, &frame->vg, sigNo))
690      restore_sigcontext(tst, &frame->uContext.uc_mcontext, &frame->fpstate);
691
692   return sizeof(*frame);
693}
694
695
696/* EXPORTED */
697void VG_(sigframe_destroy)( ThreadId tid, Bool isRT )
698{
699   Addr          esp;
700   ThreadState*  tst;
701   SizeT	 size;
702   Int		 sigNo;
703
704   tst = VG_(get_ThreadState)(tid);
705
706   /* Correctly reestablish the frame base address. */
707   esp   = tst->arch.vex.guest_ESP;
708
709   if (!isRT)
710      size = restore_sigframe(tst, (struct sigframe *)esp, &sigNo);
711   else
712      size = restore_rt_sigframe(tst, (struct rt_sigframe *)esp, &sigNo);
713
714   VG_TRACK( die_mem_stack_signal, esp - VG_STACK_REDZONE_SZB,
715             size + VG_STACK_REDZONE_SZB );
716
717   if (VG_(clo_trace_signals))
718      VG_(message)(
719         Vg_DebugMsg,
720         "VG_(signal_return) (thread %d): isRT=%d valid magic; EIP=%#x\n",
721         tid, isRT, tst->arch.vex.guest_EIP);
722
723   /* tell the tools */
724   VG_TRACK( post_deliver_signal, tid, sigNo );
725}
726
727#endif // defined(VGP_x86_linux)
728
729/*--------------------------------------------------------------------*/
730/*--- end                                                          ---*/
731/*--------------------------------------------------------------------*/
732