2 * Emulation of priviledged instructions
4 * Copyright 1995 Alexandre Julliard
12 #include "sig_context.h"
16 #define STACK_sig(context) \
17 (IS_SELECTOR_32BIT(SS_sig(context)) ? ESP_sig(context) : SP_sig(context))
19 #define MAKE_PTR(seg,off) \
20 (IS_SELECTOR_SYSTEM(seg) ? (void *)(off) : PTR_SEG_OFF_TO_LIN(seg,off))
22 #define STACK_PTR(context) \
23 (IS_SELECTOR_SYSTEM(SS_sig(context)) ? (void *)ESP_sig(context) : \
24 (PTR_SEG_OFF_TO_LIN(SS_sig(context),STACK_sig(context))))
27 /***********************************************************************
28 * INSTR_ReplaceSelector
30 * Try to replace an invalid selector by a valid one.
31 * The only selector where it is allowed to do "mov ax,40;mov es,ax"
32 * is the so called 'bimodal' selector 0x40, which points to the BIOS
33 * data segment. Used by (at least) Borland products (and programs compiled
34 * using Borland products).
36 * See Undocumented Windows, Chapter 5, __0040.
38 static WORD
INSTR_ReplaceSelector( SIGCONTEXT
*context
, WORD sel
)
42 static WORD sys_timer
= 0;
44 sys_timer
= CreateSystemTimer( 55, (FARPROC16
)DOSMEM_Tick
);
45 return DOSMEM_BiosSeg
;
47 return 0; /* Can't replace selector, crashdump */
51 /***********************************************************************
52 * INSTR_GetOperandAddr
54 * Return the address of an instruction operand (from the mod/rm byte).
56 static BYTE
*INSTR_GetOperandAddr( SIGCONTEXT
*context
, BYTE
*instr
,
57 int long_addr
, int segprefix
, int *len
)
59 int mod
, rm
, base
, index
= 0, ss
= 0, seg
= 0, off
;
61 #define GET_VAL(val,type) \
62 { *val = *(type *)instr; instr += sizeof(type); *len += sizeof(type); }
65 GET_VAL( &mod
, BYTE
);
73 case 0: return (BYTE
*)&EAX_sig(context
);
74 case 1: return (BYTE
*)&ECX_sig(context
);
75 case 2: return (BYTE
*)&EDX_sig(context
);
76 case 3: return (BYTE
*)&EBX_sig(context
);
77 case 4: return (BYTE
*)&ESP_sig(context
);
78 case 5: return (BYTE
*)&EBP_sig(context
);
79 case 6: return (BYTE
*)&ESI_sig(context
);
80 case 7: return (BYTE
*)&EDI_sig(context
);
89 GET_VAL( &sib
, BYTE
);
94 case 0: index
= EAX_sig(context
); break;
95 case 1: index
= ECX_sig(context
); break;
96 case 2: index
= EDX_sig(context
); break;
97 case 3: index
= EBX_sig(context
); break;
98 case 4: index
= 0; break;
99 case 5: index
= EBP_sig(context
); break;
100 case 6: index
= ESI_sig(context
); break;
101 case 7: index
= EDI_sig(context
); break;
107 case 0: base
= EAX_sig(context
); seg
= DS_sig(context
); break;
108 case 1: base
= ECX_sig(context
); seg
= DS_sig(context
); break;
109 case 2: base
= EDX_sig(context
); seg
= DS_sig(context
); break;
110 case 3: base
= EBX_sig(context
); seg
= DS_sig(context
); break;
111 case 4: base
= ESP_sig(context
); seg
= SS_sig(context
); break;
112 case 5: base
= EBP_sig(context
); seg
= SS_sig(context
); break;
113 case 6: base
= ESI_sig(context
); seg
= DS_sig(context
); break;
114 case 7: base
= EDI_sig(context
); seg
= DS_sig(context
); break;
119 if (rm
== 5) /* special case: ds:(disp32) */
121 GET_VAL( &base
, DWORD
);
122 seg
= DS_sig(context
);
126 case 1: /* 8-bit disp */
127 GET_VAL( &off
, BYTE
);
128 base
+= (signed char)off
;
131 case 2: /* 32-bit disp */
132 GET_VAL( &off
, DWORD
);
133 base
+= (signed long)off
;
137 else /* short address */
141 case 0: /* ds:(bx,si) */
142 base
= BX_sig(context
) + SI_sig(context
);
143 seg
= DS_sig(context
);
145 case 1: /* ds:(bx,di) */
146 base
= BX_sig(context
) + DI_sig(context
);
147 seg
= DS_sig(context
);
149 case 2: /* ss:(bp,si) */
150 base
= BP_sig(context
) + SI_sig(context
);
151 seg
= SS_sig(context
);
153 case 3: /* ss:(bp,di) */
154 base
= BP_sig(context
) + DI_sig(context
);
155 seg
= SS_sig(context
);
157 case 4: /* ds:(si) */
158 base
= SI_sig(context
);
159 seg
= DS_sig(context
);
161 case 5: /* ds:(di) */
162 base
= DI_sig(context
);
163 seg
= DS_sig(context
);
165 case 6: /* ss:(bp) */
166 base
= BP_sig(context
);
167 seg
= SS_sig(context
);
169 case 7: /* ds:(bx) */
170 base
= BX_sig(context
);
171 seg
= DS_sig(context
);
178 if (rm
== 6) /* special case: ds:(disp16) */
180 GET_VAL( &base
, WORD
);
181 seg
= DS_sig(context
);
185 case 1: /* 8-bit disp */
186 GET_VAL( &off
, BYTE
);
187 base
+= (signed char)off
;
190 case 2: /* 16-bit disp */
191 GET_VAL( &off
, WORD
);
192 base
+= (signed short)off
;
197 if (segprefix
!= -1) seg
= segprefix
;
199 /* Make sure the segment and offset are valid */
200 if (IS_SELECTOR_SYSTEM(seg
)) return (BYTE
*)(base
+ (index
<< ss
));
201 if (((seg
& 7) != 7) || IS_SELECTOR_FREE(seg
)) return NULL
;
202 if (GET_SEL_LIMIT(seg
) < (base
+ (index
<< ss
))) return NULL
;
203 return (BYTE
*)PTR_SEG_OFF_TO_LIN( seg
, (base
+ (index
<< ss
)) );
208 /***********************************************************************
211 * Emulate the LDS (and LES,LFS,etc.) instruction.
213 static BOOL32
INSTR_EmulateLDS( SIGCONTEXT
*context
, BYTE
*instr
, int long_op
,
214 int long_addr
, int segprefix
, int *len
)
217 BYTE
*regmodrm
= instr
+ 1 + (*instr
== 0x0f);
218 BYTE
*addr
= INSTR_GetOperandAddr( context
, regmodrm
,
219 long_addr
, segprefix
, len
);
221 return FALSE
; /* Unable to emulate it */
222 seg
= *(WORD
*)(addr
+ (long_op
? 4 : 2));
224 if (!(seg
= INSTR_ReplaceSelector( context
, seg
)))
225 return FALSE
; /* Unable to emulate it */
227 /* Now store the offset in the correct register */
229 switch((*regmodrm
>> 3) & 7)
232 if (long_op
) EAX_sig(context
) = *(DWORD
*)addr
;
233 else AX_sig(context
) = *(WORD
*)addr
;
236 if (long_op
) ECX_sig(context
) = *(DWORD
*)addr
;
237 else CX_sig(context
) = *(WORD
*)addr
;
240 if (long_op
) EDX_sig(context
) = *(DWORD
*)addr
;
241 else DX_sig(context
) = *(WORD
*)addr
;
244 if (long_op
) EBX_sig(context
) = *(DWORD
*)addr
;
245 else BX_sig(context
) = *(WORD
*)addr
;
248 if (long_op
) ESP_sig(context
) = *(DWORD
*)addr
;
249 else SP_sig(context
) = *(WORD
*)addr
;
252 if (long_op
) EBP_sig(context
) = *(DWORD
*)addr
;
253 else BP_sig(context
) = *(WORD
*)addr
;
256 if (long_op
) ESI_sig(context
) = *(DWORD
*)addr
;
257 else SI_sig(context
) = *(WORD
*)addr
;
260 if (long_op
) EDI_sig(context
) = *(DWORD
*)addr
;
261 else DI_sig(context
) = *(WORD
*)addr
;
265 /* Store the correct segment in the segment register */
269 case 0xc4: ES_sig(context
) = seg
; break; /* les */
270 case 0xc5: DS_sig(context
) = seg
; break; /* lds */
271 case 0x0f: switch(instr
[1])
273 case 0xb2: SS_sig(context
) = seg
; break; /* lss */
275 case 0xb4: FS_sig(context
) = seg
; break; /* lfs */
278 case 0xb5: GS_sig(context
) = seg
; break; /* lgs */
284 /* Add the opcode size to the total length */
286 *len
+= 1 + (*instr
== 0x0f);
291 /***********************************************************************
292 * INSTR_EmulateInstruction
294 * Emulate a priviledged instruction. Returns TRUE if emulation successful.
296 BOOL32
INSTR_EmulateInstruction( SIGCONTEXT
*context
)
298 int prefix
, segprefix
, prefixlen
, len
, repX
, long_op
, long_addr
;
302 /* Check for page-fault */
304 #if defined(TRAP_sig) && defined(CR2_sig)
305 if (TRAP_sig(context
) == 0x0e
306 && VIRTUAL_HandleFault( (LPVOID
)CR2_sig(context
) )) return TRUE
;
309 long_op
= long_addr
= IS_SELECTOR_32BIT(CS_sig(context
));
310 instr
= (BYTE
*)MAKE_PTR(CS_sig(context
),EIP_sig(context
));
311 if (!instr
) return FALSE
;
313 /* First handle any possible prefix */
315 segprefix
= -1; /* no prefix */
324 segprefix
= CS_sig(context
);
327 segprefix
= SS_sig(context
);
330 segprefix
= DS_sig(context
);
333 segprefix
= ES_sig(context
);
337 segprefix
= FS_sig(context
);
342 segprefix
= GS_sig(context
);
346 long_op
= !long_op
; /* opcode size prefix */
349 long_addr
= !long_addr
; /* addr size prefix */
351 case 0xf0: /* lock */
353 case 0xf2: /* repne */
356 case 0xf3: /* repe */
360 prefix
= 0; /* no more prefixes */
370 /* Now look at the actual instruction */
374 case 0x07: /* pop es */
375 case 0x17: /* pop ss */
376 case 0x1f: /* pop ds */
378 WORD seg
= *(WORD
*)STACK_PTR( context
);
379 if ((seg
= INSTR_ReplaceSelector( context
, seg
)) != 0)
383 case 0x07: ES_sig(context
) = seg
; break;
384 case 0x17: SS_sig(context
) = seg
; break;
385 case 0x1f: DS_sig(context
) = seg
; break;
387 STACK_sig(context
) += long_op
? 4 : 2;
388 EIP_sig(context
) += prefixlen
+ 1;
392 break; /* Unable to emulate it */
394 case 0x0f: /* extended instruction */
398 case 0xa1: /* pop fs */
400 WORD seg
= *(WORD
*)STACK_PTR( context
);
401 if ((seg
= INSTR_ReplaceSelector( context
, seg
)) != 0)
403 FS_sig(context
) = seg
;
404 STACK_sig(context
) += long_op
? 4 : 2;
405 EIP_sig(context
) += prefixlen
+ 2;
413 case 0xa9: /* pop gs */
415 WORD seg
= *(WORD
*)STACK_PTR( context
);
416 if ((seg
= INSTR_ReplaceSelector( context
, seg
)) != 0)
418 GS_sig(context
) = seg
;
419 STACK_sig(context
) += long_op
? 4 : 2;
420 EIP_sig(context
) += prefixlen
+ 2;
427 case 0xb2: /* lss addr,reg */
429 case 0xb4: /* lfs addr,reg */
432 case 0xb5: /* lgs addr,reg */
434 if (INSTR_EmulateLDS( context
, instr
, long_op
,
435 long_addr
, segprefix
, &len
))
437 EIP_sig(context
) += prefixlen
+ len
;
442 break; /* Unable to emulate it */
444 case 0x6c: /* insb */
445 case 0x6d: /* insw/d */
446 case 0x6e: /* outsb */
447 case 0x6f: /* outsw/d */
449 int typ
= *instr
; /* Just in case it's overwritten. */
450 int outp
= (typ
>= 0x6e);
451 unsigned long count
= repX
?
452 (long_addr
? ECX_sig(context
) : CX_sig(context
)) : 1;
453 int opsize
= (typ
& 1) ? (long_op
? 4 : 2) : 1;
454 int step
= (EFL_sig(context
) & 0x400) ? -opsize
: +opsize
;
455 int seg
= outp
? DS_sig(context
) : ES_sig(context
); /* FIXME: is this right? */
458 /* FIXME: Check segment readable. */
461 /* FIXME: Check segment writeable. */
466 ECX_sig(context
) = 0;
476 long_addr
? ESI_sig(context
) : SI_sig(context
));
477 if (long_addr
) ESI_sig(context
) += step
;
478 else SI_sig(context
) += step
;
483 long_addr
? EDI_sig(context
) : DI_sig(context
));
484 if (long_addr
) EDI_sig(context
) += step
;
485 else DI_sig(context
) += step
;
491 *((BYTE
*)data
) = IO_inport( DX_sig(context
), 1);
495 *((DWORD
*)data
) = IO_inport( DX_sig(context
), 4);
497 *((WORD
*)data
) = IO_inport( DX_sig(context
), 2);
500 IO_outport( DX_sig(context
), 1, *((BYTE
*)data
));
504 IO_outport( DX_sig(context
), 4, *((DWORD
*)data
));
506 IO_outport( DX_sig(context
), 2, *((WORD
*)data
));
510 EIP_sig(context
) += prefixlen
+ 1;
514 case 0x8e: /* mov XX,segment_reg */
517 BYTE
*addr
= INSTR_GetOperandAddr(context
, instr
+ 1,
518 long_addr
, segprefix
, &len
);
520 break; /* Unable to emulate it */
522 if (!(seg
= INSTR_ReplaceSelector( context
, seg
)))
523 break; /* Unable to emulate it */
525 switch((instr
[1] >> 3) & 7)
528 ES_sig(context
) = seg
;
529 EIP_sig(context
) += prefixlen
+ len
+ 1;
534 SS_sig(context
) = seg
;
535 EIP_sig(context
) += prefixlen
+ len
+ 1;
538 DS_sig(context
) = seg
;
539 EIP_sig(context
) += prefixlen
+ len
+ 1;
543 FS_sig(context
) = seg
;
544 EIP_sig(context
) += prefixlen
+ len
+ 1;
549 GS_sig(context
) = seg
;
550 EIP_sig(context
) += prefixlen
+ len
+ 1;
558 break; /* Unable to emulate it */
560 case 0xc4: /* les addr,reg */
561 case 0xc5: /* lds addr,reg */
562 if (INSTR_EmulateLDS( context
, instr
, long_op
,
563 long_addr
, segprefix
, &len
))
565 EIP_sig(context
) += prefixlen
+ len
;
568 break; /* Unable to emulate it */
570 case 0xcd: /* int <XX> */
573 ERR(int, "int xx from 32-bit code is not supported.\n");
574 break; /* Unable to emulate it */
578 FARPROC16 addr
= INT_GetPMHandler( instr
[1] );
579 WORD
*stack
= (WORD
*)STACK_PTR( context
);
580 /* Push the flags and return address on the stack */
581 *(--stack
) = FL_sig(context
);
582 *(--stack
) = CS_sig(context
);
583 *(--stack
) = IP_sig(context
) + prefixlen
+ 2;
584 STACK_sig(context
) -= 3 * sizeof(WORD
);
585 /* Jump to the interrupt handler */
586 CS_sig(context
) = HIWORD(addr
);
587 EIP_sig(context
) = LOWORD(addr
);
591 case 0xcf: /* iret */
594 DWORD
*stack
= (DWORD
*)STACK_PTR( context
);
595 EIP_sig(context
) = *stack
++;
596 CS_sig(context
) = *stack
++;
597 EFL_sig(context
) = *stack
;
598 STACK_sig(context
) += 3*sizeof(DWORD
); /* Pop the return address and flags */
602 WORD
*stack
= (WORD
*)STACK_PTR( context
);
603 EIP_sig(context
) = *stack
++;
604 CS_sig(context
) = *stack
++;
605 FL_sig(context
) = *stack
;
606 STACK_sig(context
) += 3*sizeof(WORD
); /* Pop the return address and flags */
610 case 0xe4: /* inb al,XX */
611 AL_sig(context
) = IO_inport( instr
[1], 1 );
612 EIP_sig(context
) += prefixlen
+ 2;
615 case 0xe5: /* in (e)ax,XX */
616 if (long_op
) EAX_sig(context
) = IO_inport( instr
[1], 4 );
617 else AX_sig(context
) = IO_inport( instr
[1], 2 );
618 EIP_sig(context
) += prefixlen
+ 2;
621 case 0xe6: /* outb XX,al */
622 IO_outport( instr
[1], 1, AL_sig(context
) );
623 EIP_sig(context
) += prefixlen
+ 2;
626 case 0xe7: /* out XX,(e)ax */
627 if (long_op
) IO_outport( instr
[1], 4, EAX_sig(context
) );
628 else IO_outport( instr
[1], 2, AX_sig(context
) );
629 EIP_sig(context
) += prefixlen
+ 2;
632 case 0xec: /* inb al,dx */
633 AL_sig(context
) = IO_inport( DX_sig(context
), 1 );
634 EIP_sig(context
) += prefixlen
+ 1;
637 case 0xed: /* in (e)ax,dx */
638 if (long_op
) EAX_sig(context
) = IO_inport( DX_sig(context
), 4 );
639 else AX_sig(context
) = IO_inport( DX_sig(context
), 2 );
640 EIP_sig(context
) += prefixlen
+ 1;
643 case 0xee: /* outb dx,al */
644 IO_outport( DX_sig(context
), 1, AL_sig(context
) );
645 EIP_sig(context
) += prefixlen
+ 1;
648 case 0xef: /* out dx,(e)ax */
649 if (long_op
) IO_outport( DX_sig(context
), 4, EAX_sig(context
) );
650 else IO_outport( DX_sig(context
), 2, AX_sig(context
) );
651 EIP_sig(context
) += prefixlen
+ 1;
654 case 0xfa: /* cli, ignored */
655 EIP_sig(context
) += prefixlen
+ 1;
658 case 0xfb: /* sti, ignored */
659 EIP_sig(context
) += prefixlen
+ 1;
664 /* Check for Win16 __GP handler */
665 gpHandler
= HasGPHandler( PTR_SEG_OFF_TO_SEGPTR( CS_sig(context
),
666 EIP_sig(context
) ) );
669 WORD
*stack
= (WORD
*)STACK_PTR( context
);
670 *--stack
= CS_sig(context
);
671 *--stack
= EIP_sig(context
);
672 STACK_sig(context
) -= 2*sizeof(WORD
);
674 CS_sig(context
) = SELECTOROF( gpHandler
);
675 EIP_sig(context
) = OFFSETOF( gpHandler
);
679 MSG("Unexpected Windows program segfault"
680 " - opcode = %x\n", *instr
);
681 return FALSE
; /* Unable to emulate it */