| /* |
| * Emulation of priviledged instructions |
| * |
| * Copyright 1995 Alexandre Julliard |
| */ |
| |
| #include <stdio.h> |
| #include "windows.h" |
| #include "ldt.h" |
| #include "miscemu.h" |
| #include "sig_context.h" |
| |
| |
| #define STACK_sig(context) \ |
| ((GET_SEL_FLAGS(SS_sig(context)) & LDT_FLAGS_32BIT) ? \ |
| ESP_sig(context) : SP_sig(context)) |
| |
| #define STACK_PTR(context) \ |
| (PTR_SEG_OFF_TO_LIN(SS_sig(context),STACK_sig(context))) |
| |
| /*********************************************************************** |
| * INSTR_ReplaceSelector |
| * |
| * Try to replace an invalid selector by a valid one. |
| * For now, only selector 0x40 is handled here. |
| */ |
| static WORD INSTR_ReplaceSelector( SIGCONTEXT *context, WORD sel) |
| { |
| if (sel == 0x40) |
| { |
| static WORD sys_timer = 0; |
| fprintf( stderr, "Direct access to segment 0x40 (cs:ip=%04x:%04lx).\n", |
| CS_sig(context), EIP_sig(context) ); |
| if (!sys_timer) |
| sys_timer = CreateSystemTimer( 55, (FARPROC16)DOSMEM_Tick ); |
| return DOSMEM_BiosSeg; |
| } |
| return 0; /* Can't replace selector */ |
| } |
| |
| |
| /*********************************************************************** |
| * INSTR_GetOperandAddr |
| * |
| * Return the address of an instruction operand (from the mod/rm byte). |
| */ |
| static BYTE *INSTR_GetOperandAddr( SIGCONTEXT *context, BYTE *instr, |
| int long_addr, int segprefix, int *len ) |
| { |
| int mod, rm, base, index = 0, ss = 0, seg = 0, off; |
| |
| #define GET_VAL(val,type) \ |
| { *val = *(type *)instr; instr += sizeof(type); *len += sizeof(type); } |
| |
| *len = 0; |
| GET_VAL( &mod, BYTE ); |
| rm = mod & 7; |
| mod >>= 6; |
| |
| if (mod == 3) |
| { |
| switch(rm) |
| { |
| case 0: return (BYTE *)&EAX_sig(context); |
| case 1: return (BYTE *)&ECX_sig(context); |
| case 2: return (BYTE *)&EDX_sig(context); |
| case 3: return (BYTE *)&EBX_sig(context); |
| case 4: return (BYTE *)&ESP_sig(context); |
| case 5: return (BYTE *)&EBP_sig(context); |
| case 6: return (BYTE *)&ESI_sig(context); |
| case 7: return (BYTE *)&EDI_sig(context); |
| } |
| } |
| |
| if (long_addr) |
| { |
| if (rm == 4) |
| { |
| BYTE sib; |
| GET_VAL( &sib, BYTE ); |
| rm = sib & 7; |
| ss = sib >> 6; |
| switch(sib >> 3) |
| { |
| case 0: index = EAX_sig(context); break; |
| case 1: index = ECX_sig(context); break; |
| case 2: index = EDX_sig(context); break; |
| case 3: index = EBX_sig(context); break; |
| case 4: index = 0; break; |
| case 5: index = EBP_sig(context); break; |
| case 6: index = ESI_sig(context); break; |
| case 7: index = EDI_sig(context); break; |
| } |
| } |
| |
| switch(rm) |
| { |
| case 0: base = EAX_sig(context); seg = DS_sig(context); break; |
| case 1: base = ECX_sig(context); seg = DS_sig(context); break; |
| case 2: base = EDX_sig(context); seg = DS_sig(context); break; |
| case 3: base = EBX_sig(context); seg = DS_sig(context); break; |
| case 4: base = ESP_sig(context); seg = SS_sig(context); break; |
| case 5: base = EBP_sig(context); seg = SS_sig(context); break; |
| case 6: base = ESI_sig(context); seg = DS_sig(context); break; |
| case 7: base = EDI_sig(context); seg = DS_sig(context); break; |
| } |
| switch (mod) |
| { |
| case 0: |
| if (rm == 5) /* special case: ds:(disp32) */ |
| { |
| GET_VAL( &base, DWORD ); |
| seg = DS_sig(context); |
| } |
| break; |
| |
| case 1: /* 8-bit disp */ |
| GET_VAL( &off, BYTE ); |
| base += (signed char)off; |
| break; |
| |
| case 2: /* 32-bit disp */ |
| GET_VAL( &off, DWORD ); |
| base += (signed long)off; |
| break; |
| } |
| } |
| else /* short address */ |
| { |
| switch(rm) |
| { |
| case 0: /* ds:(bx,si) */ |
| base = BX_sig(context) + SI_sig(context); |
| seg = DS_sig(context); |
| break; |
| case 1: /* ds:(bx,di) */ |
| base = BX_sig(context) + DI_sig(context); |
| seg = DS_sig(context); |
| break; |
| case 2: /* ss:(bp,si) */ |
| base = BP_sig(context) + SI_sig(context); |
| seg = SS_sig(context); |
| break; |
| case 3: /* ss:(bp,di) */ |
| base = BP_sig(context) + DI_sig(context); |
| seg = SS_sig(context); |
| break; |
| case 4: /* ds:(si) */ |
| base = SI_sig(context); |
| seg = DS_sig(context); |
| break; |
| case 5: /* ds:(di) */ |
| base = DI_sig(context); |
| seg = DS_sig(context); |
| break; |
| case 6: /* ss:(bp) */ |
| base = BP_sig(context); |
| seg = SS_sig(context); |
| break; |
| case 7: /* ds:(bx) */ |
| base = BX_sig(context); |
| seg = DS_sig(context); |
| break; |
| } |
| |
| switch(mod) |
| { |
| case 0: |
| if (rm == 6) /* special case: ds:(disp16) */ |
| { |
| GET_VAL( &base, WORD ); |
| seg = DS_sig(context); |
| } |
| break; |
| |
| case 1: /* 8-bit disp */ |
| GET_VAL( &off, BYTE ); |
| base += (signed char)off; |
| break; |
| |
| case 2: /* 16-bit disp */ |
| GET_VAL( &off, WORD ); |
| base += (signed short)off; |
| break; |
| } |
| base &= 0xffff; |
| } |
| if (segprefix != -1) seg = segprefix; |
| |
| /* Make sure the segment and offset are valid */ |
| if (((seg & 7) != 7) || IS_SELECTOR_FREE(seg)) return NULL; |
| if (GET_SEL_LIMIT(seg) < (base + (index << ss))) return NULL; |
| return (BYTE *)PTR_SEG_OFF_TO_LIN( seg, (base + (index << ss)) ); |
| #undef GET_VAL |
| } |
| |
| |
| /*********************************************************************** |
| * INSTR_EmulateLDS |
| * |
| * Emulate the LDS (and LES,LFS,etc.) instruction. |
| */ |
| static BOOL32 INSTR_EmulateLDS( SIGCONTEXT *context, BYTE *instr, int long_op, |
| int long_addr, int segprefix, int *len ) |
| { |
| WORD seg; |
| BYTE *regmodrm = instr + 1 + (*instr == 0x0f); |
| BYTE *addr = INSTR_GetOperandAddr( context, regmodrm, |
| long_addr, segprefix, len ); |
| if (!addr) |
| return FALSE; /* Unable to emulate it */ |
| seg = *(WORD *)(addr + (long_op ? 4 : 2)); |
| |
| if (!(seg = INSTR_ReplaceSelector( context, seg ))) |
| return FALSE; /* Unable to emulate it */ |
| |
| /* Now store the offset in the correct register */ |
| |
| switch((*regmodrm >> 3) & 7) |
| { |
| case 0: |
| if (long_op) EAX_sig(context) = *(DWORD *)addr; |
| else AX_sig(context) = *(WORD *)addr; |
| break; |
| case 1: |
| if (long_op) ECX_sig(context) = *(DWORD *)addr; |
| else CX_sig(context) = *(WORD *)addr; |
| break; |
| case 2: |
| if (long_op) EDX_sig(context) = *(DWORD *)addr; |
| else DX_sig(context) = *(WORD *)addr; |
| break; |
| case 3: |
| if (long_op) EBX_sig(context) = *(DWORD *)addr; |
| else BX_sig(context) = *(WORD *)addr; |
| break; |
| case 4: |
| if (long_op) ESP_sig(context) = *(DWORD *)addr; |
| else SP_sig(context) = *(WORD *)addr; |
| break; |
| case 5: |
| if (long_op) EBP_sig(context) = *(DWORD *)addr; |
| else BP_sig(context) = *(WORD *)addr; |
| break; |
| case 6: |
| if (long_op) ESI_sig(context) = *(DWORD *)addr; |
| else SI_sig(context) = *(WORD *)addr; |
| break; |
| case 7: |
| if (long_op) EDI_sig(context) = *(DWORD *)addr; |
| else DI_sig(context) = *(WORD *)addr; |
| break; |
| } |
| |
| /* Store the correct segment in the segment register */ |
| |
| switch(*instr) |
| { |
| case 0xc4: ES_sig(context) = seg; break; /* les */ |
| case 0xc5: DS_sig(context) = seg; break; /* lds */ |
| case 0x0f: switch(instr[1]) |
| { |
| case 0xb2: SS_sig(context) = seg; break; /* lss */ |
| #ifdef FS_sig |
| case 0xb4: FS_sig(context) = seg; break; /* lfs */ |
| #endif |
| #ifdef GS_sig |
| case 0xb5: GS_sig(context) = seg; break; /* lgs */ |
| #endif |
| } |
| break; |
| } |
| |
| /* Add the opcode size to the total length */ |
| |
| *len += 1 + (*instr == 0x0f); |
| return TRUE; |
| } |
| |
| |
| /*********************************************************************** |
| * INSTR_EmulateInstruction |
| * |
| * Emulate a priviledged instruction. Returns TRUE if emulation successful. |
| */ |
| BOOL32 INSTR_EmulateInstruction( SIGCONTEXT *context ) |
| { |
| int prefix, segprefix, prefixlen, len, repX, long_op, long_addr; |
| BYTE *instr; |
| |
| long_op = long_addr = (GET_SEL_FLAGS(CS_sig(context)) & LDT_FLAGS_32BIT) != 0; |
| instr = (BYTE *) PTR_SEG_OFF_TO_LIN( CS_sig(context), EIP_sig(context) ); |
| |
| /* First handle any possible prefix */ |
| |
| segprefix = -1; /* no prefix */ |
| prefix = 1; |
| repX = 0; |
| prefixlen = 0; |
| while(prefix) |
| { |
| switch(*instr) |
| { |
| case 0x2e: |
| segprefix = CS_sig(context); |
| break; |
| case 0x36: |
| segprefix = SS_sig(context); |
| break; |
| case 0x3e: |
| segprefix = DS_sig(context); |
| break; |
| case 0x26: |
| segprefix = ES_sig(context); |
| break; |
| #ifdef FS_sig |
| case 0x64: |
| segprefix = FS_sig(context); |
| break; |
| #endif |
| #ifdef GS_sig |
| case 0x65: |
| segprefix = GS_sig(context); |
| break; |
| #endif |
| case 0x66: |
| long_op = !long_op; /* opcode size prefix */ |
| break; |
| case 0x67: |
| long_addr = !long_addr; /* addr size prefix */ |
| break; |
| case 0xf0: /* lock */ |
| break; |
| case 0xf2: /* repne */ |
| repX = 1; |
| break; |
| case 0xf3: /* repe */ |
| repX = 2; |
| break; |
| default: |
| prefix = 0; /* no more prefixes */ |
| break; |
| } |
| if (prefix) |
| { |
| instr++; |
| prefixlen++; |
| } |
| } |
| |
| /* Now look at the actual instruction */ |
| |
| switch(*instr) |
| { |
| case 0x07: /* pop es */ |
| case 0x17: /* pop ss */ |
| case 0x1f: /* pop ds */ |
| { |
| WORD seg = *(WORD *)STACK_PTR( context ); |
| if ((seg = INSTR_ReplaceSelector( context, seg )) != 0) |
| { |
| switch(*instr) |
| { |
| case 0x07: ES_sig(context) = seg; break; |
| case 0x17: SS_sig(context) = seg; break; |
| case 0x1f: DS_sig(context) = seg; break; |
| } |
| STACK_sig(context) += long_op ? 4 : 2; |
| EIP_sig(context) += prefixlen + 1; |
| return TRUE; |
| } |
| } |
| break; /* Unable to emulate it */ |
| |
| case 0x0f: /* extended instruction */ |
| switch(instr[1]) |
| { |
| #ifdef FS_sig |
| case 0xa1: /* pop fs */ |
| { |
| WORD seg = *(WORD *)STACK_PTR( context ); |
| if ((seg = INSTR_ReplaceSelector( context, seg )) != 0) |
| { |
| FS_sig(context) = seg; |
| STACK_sig(context) += long_op ? 4 : 2; |
| EIP_sig(context) += prefixlen + 2; |
| return TRUE; |
| } |
| } |
| break; |
| #endif /* FS_sig */ |
| |
| #ifdef GS_sig |
| case 0xa9: /* pop gs */ |
| { |
| WORD seg = *(WORD *)STACK_PTR( context ); |
| if ((seg = INSTR_ReplaceSelector( context, seg )) != 0) |
| { |
| GS_sig(context) = seg; |
| STACK_sig(context) += long_op ? 4 : 2; |
| EIP_sig(context) += prefixlen + 2; |
| return TRUE; |
| } |
| } |
| break; |
| #endif /* GS_sig */ |
| |
| case 0xb2: /* lss addr,reg */ |
| #ifdef FS_sig |
| case 0xb4: /* lfs addr,reg */ |
| #endif |
| #ifdef GS_sig |
| case 0xb5: /* lgs addr,reg */ |
| #endif |
| if (INSTR_EmulateLDS( context, instr, long_op, |
| long_addr, segprefix, &len )) |
| { |
| EIP_sig(context) += prefixlen + len; |
| return TRUE; |
| } |
| break; |
| } |
| break; /* Unable to emulate it */ |
| |
| case 0x6c: /* insb */ |
| case 0x6d: /* insw/d */ |
| case 0x6e: /* outsb */ |
| case 0x6f: /* outsw/d */ |
| { |
| int typ = *instr; /* Just in case it's overwritten. */ |
| int outp = (typ >= 0x6e); |
| unsigned long count = repX ? |
| (long_addr ? ECX_sig(context) : CX_sig(context)) : 1; |
| int opsize = (typ & 1) ? (long_op ? 4 : 2) : 1; |
| int step = (EFL_sig(context) & 0x400) ? -opsize : +opsize; |
| int seg = outp ? DS_sig(context) : ES_sig(context); /* FIXME: is this right? */ |
| |
| if (outp) |
| /* FIXME: Check segment readable. */ |
| (void)0; |
| else |
| /* FIXME: Check segment writeable. */ |
| (void)0; |
| |
| if (repX) |
| if (long_addr) |
| ECX_sig(context) = 0; |
| else |
| CX_sig(context) = 0; |
| |
| while (count-- > 0) |
| { |
| void *data; |
| if (outp) |
| { |
| data = PTR_SEG_OFF_TO_LIN (seg, |
| long_addr ? ESI_sig(context) : SI_sig(context)); |
| if (long_addr) ESI_sig(context) += step; |
| else SI_sig(context) += step; |
| } |
| else |
| { |
| data = PTR_SEG_OFF_TO_LIN (seg, |
| long_addr ? EDI_sig(context) : DI_sig(context)); |
| if (long_addr) EDI_sig(context) += step; |
| else DI_sig(context) += step; |
| } |
| |
| switch (typ) |
| { |
| case 0x6c: |
| *((BYTE *)data) = IO_inport( DX_sig(context), 1); |
| break; |
| case 0x6d: |
| if (long_op) |
| *((DWORD *)data) = IO_inport( DX_sig(context), 4); |
| else |
| *((WORD *)data) = IO_inport( DX_sig(context), 2); |
| break; |
| case 0x6e: |
| IO_outport( DX_sig(context), 1, *((BYTE *)data)); |
| break; |
| case 0x6f: |
| if (long_op) |
| IO_outport( DX_sig(context), 4, *((DWORD *)data)); |
| else |
| IO_outport( DX_sig(context), 2, *((WORD *)data)); |
| break; |
| } |
| } |
| EIP_sig(context) += prefixlen + 1; |
| } |
| return TRUE; |
| |
| case 0x8e: /* mov XX,segment_reg */ |
| { |
| WORD seg; |
| BYTE *addr = INSTR_GetOperandAddr(context, instr + 1, |
| long_addr, segprefix, &len ); |
| if (!addr) |
| break; /* Unable to emulate it */ |
| seg = *(WORD *)addr; |
| if (!(seg = INSTR_ReplaceSelector( context, seg ))) |
| break; /* Unable to emulate it */ |
| |
| switch((instr[1] >> 3) & 7) |
| { |
| case 0: |
| ES_sig(context) = seg; |
| EIP_sig(context) += prefixlen + len + 1; |
| return TRUE; |
| case 1: /* cs */ |
| break; |
| case 2: |
| SS_sig(context) = seg; |
| EIP_sig(context) += prefixlen + len + 1; |
| return TRUE; |
| case 3: |
| DS_sig(context) = seg; |
| EIP_sig(context) += prefixlen + len + 1; |
| return TRUE; |
| case 4: |
| #ifdef FS_sig |
| FS_sig(context) = seg; |
| EIP_sig(context) += prefixlen + len + 1; |
| return TRUE; |
| #endif |
| case 5: |
| #ifdef GS_sig |
| GS_sig(context) = seg; |
| EIP_sig(context) += prefixlen + len + 1; |
| return TRUE; |
| #endif |
| case 6: /* unused */ |
| case 7: /* unused */ |
| break; |
| } |
| } |
| break; /* Unable to emulate it */ |
| |
| case 0xc4: /* les addr,reg */ |
| case 0xc5: /* lds addr,reg */ |
| if (INSTR_EmulateLDS( context, instr, long_op, |
| long_addr, segprefix, &len )) |
| { |
| EIP_sig(context) += prefixlen + len; |
| return TRUE; |
| } |
| break; /* Unable to emulate it */ |
| |
| case 0xcd: /* int <XX> */ |
| if (long_op) |
| { |
| fprintf(stderr, "int xx from 32-bit code is not supported.\n"); |
| break; /* Unable to emulate it */ |
| } |
| else |
| { |
| FARPROC16 addr = INT_GetHandler( instr[1] ); |
| WORD *stack = (WORD *)STACK_PTR( context ); |
| /* Push the flags and return address on the stack */ |
| *(--stack) = FL_sig(context); |
| *(--stack) = CS_sig(context); |
| *(--stack) = IP_sig(context) + prefixlen + 2; |
| STACK_sig(context) -= 3 * sizeof(WORD); |
| /* Jump to the interrupt handler */ |
| CS_sig(context) = HIWORD(addr); |
| EIP_sig(context) = LOWORD(addr); |
| } |
| return TRUE; |
| |
| case 0xcf: /* iret */ |
| if (long_op) |
| { |
| DWORD *stack = (DWORD *)STACK_PTR( context ); |
| EIP_sig(context) = *stack++; |
| CS_sig(context) = *stack++; |
| EFL_sig(context) = *stack; |
| STACK_sig(context) += 3*sizeof(DWORD); /* Pop the return address and flags */ |
| } |
| else |
| { |
| WORD *stack = (WORD *)STACK_PTR( context ); |
| EIP_sig(context) = *stack++; |
| CS_sig(context) = *stack++; |
| FL_sig(context) = *stack; |
| STACK_sig(context) += 3*sizeof(WORD); /* Pop the return address and flags */ |
| } |
| return TRUE; |
| |
| case 0xe4: /* inb al,XX */ |
| AL_sig(context) = IO_inport( instr[1], 1 ); |
| EIP_sig(context) += prefixlen + 2; |
| return TRUE; |
| |
| case 0xe5: /* in (e)ax,XX */ |
| if (long_op) EAX_sig(context) = IO_inport( instr[1], 4 ); |
| else AX_sig(context) = IO_inport( instr[1], 2 ); |
| EIP_sig(context) += prefixlen + 2; |
| return TRUE; |
| |
| case 0xe6: /* outb XX,al */ |
| IO_outport( instr[1], 1, AL_sig(context) ); |
| EIP_sig(context) += prefixlen + 2; |
| return TRUE; |
| |
| case 0xe7: /* out XX,(e)ax */ |
| if (long_op) IO_outport( instr[1], 4, EAX_sig(context) ); |
| else IO_outport( instr[1], 2, AX_sig(context) ); |
| EIP_sig(context) += prefixlen + 2; |
| return TRUE; |
| |
| case 0xec: /* inb al,dx */ |
| AL_sig(context) = IO_inport( DX_sig(context), 1 ); |
| EIP_sig(context) += prefixlen + 1; |
| return TRUE; |
| |
| case 0xed: /* in (e)ax,dx */ |
| if (long_op) EAX_sig(context) = IO_inport( DX_sig(context), 4 ); |
| else AX_sig(context) = IO_inport( DX_sig(context), 2 ); |
| EIP_sig(context) += prefixlen + 1; |
| return TRUE; |
| |
| case 0xee: /* outb dx,al */ |
| IO_outport( DX_sig(context), 1, AL_sig(context) ); |
| EIP_sig(context) += prefixlen + 1; |
| return TRUE; |
| |
| case 0xef: /* out dx,(e)ax */ |
| if (long_op) IO_outport( DX_sig(context), 4, EAX_sig(context) ); |
| else IO_outport( DX_sig(context), 2, AX_sig(context) ); |
| EIP_sig(context) += prefixlen + 1; |
| return TRUE; |
| |
| case 0xfa: /* cli, ignored */ |
| EIP_sig(context) += prefixlen + 1; |
| return TRUE; |
| |
| case 0xfb: /* sti, ignored */ |
| EIP_sig(context) += prefixlen + 1; |
| return TRUE; |
| } |
| fprintf(stderr, "Unexpected Windows program segfault" |
| " - opcode = %x\n", *instr); |
| return FALSE; /* Unable to emulate it */ |
| } |
