This source file includes following definitions.
- math_emulate
- valid_prefix
- math_abort
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26 #include <linux/signal.h>
27 #include <linux/segment.h>
28
29 #include "fpu_system.h"
30 #include "fpu_emu.h"
31 #include "exception.h"
32 #include "control_w.h"
33 #include "status_w.h"
34
35 #include <asm/segment.h>
36
37 #define __BAD__ FPU_illegal
38
39 #ifndef NO_UNDOC_CODE
40
41
42
43
44
45
46 #define _d9_d8_ fstp_i
47 #define _dc_d0_ fcom_st
48 #define _dc_d8_ fcompst
49 #define _dd_c8_ fxch_i
50 #define _de_d0_ fcompst
51 #define _df_c0_ ffreep
52 #define _df_c8_ fxch_i
53 #define _df_d0_ fstp_i
54 #define _df_d8_ fstp_i
55
56 static FUNC const st_instr_table[64] = {
57 fadd__, fld_i_, __BAD__, __BAD__, fadd_i, ffree_, faddp_, _df_c0_,
58 fmul__, fxch_i, __BAD__, __BAD__, fmul_i, _dd_c8_, fmulp_, _df_c8_,
59 fcom_st, fp_nop, __BAD__, __BAD__, _dc_d0_, fst_i_, _de_d0_, _df_d0_,
60 fcompst, _d9_d8_, __BAD__, __BAD__, _dc_d8_, fstp_i, fcompp, _df_d8_,
61 fsub__, fp_etc, __BAD__, finit_, fsubri, fucom_, fsubrp, fstsw_,
62 fsubr_, fconst, fucompp, __BAD__, fsub_i, fucomp, fsubp_, __BAD__,
63 fdiv__, trig_a, __BAD__, __BAD__, fdivri, __BAD__, fdivrp, __BAD__,
64 fdivr_, trig_b, __BAD__, __BAD__, fdiv_i, __BAD__, fdivp_, __BAD__,
65 };
66
67 #else
68
69 static FUNC const st_instr_table[64] = {
70 fadd__, fld_i_, __BAD__, __BAD__, fadd_i, ffree_, faddp_, __BAD__,
71 fmul__, fxch_i, __BAD__, __BAD__, fmul_i, __BAD__, fmulp_, __BAD__,
72 fcom_st, fp_nop, __BAD__, __BAD__, __BAD__, fst_i_, __BAD__, __BAD__,
73 fcompst, __BAD__, __BAD__, __BAD__, __BAD__, fstp_i, fcompp, __BAD__,
74 fsub__, fp_etc, __BAD__, finit_, fsubri, fucom_, fsubrp, fstsw_,
75 fsubr_, fconst, fucompp, __BAD__, fsub_i, fucomp, fsubp_, __BAD__,
76 fdiv__, trig_a, __BAD__, __BAD__, fdivri, __BAD__, fdivrp, __BAD__,
77 fdivr_, trig_b, __BAD__, __BAD__, fdiv_i, __BAD__, fdivp_, __BAD__,
78 };
79
80 #endif NO_UNDOC_CODE
81
82
83 #define _NONE_ 0
84 #define _REG0_ 1
85 #define _REGI_ 2
86 #define _REGi_ 0
87 #define _PUSH_ 3
88 #define _null_ 4
89 #define _REGIi 5
90 #define _REGIp 6
91 #define _REGIc 0
92 #define _REGIn 0
93
94 #ifndef NO_UNDOC_CODE
95
96
97
98 static unsigned char const type_table[64] = {
99 _REGI_, _NONE_, _null_, _null_, _REGIi, _REGi_, _REGIp, _REGi_,
100 _REGI_, _REGIn, _null_, _null_, _REGIi, _REGI_, _REGIp, _REGI_,
101 _REGIc, _NONE_, _null_, _null_, _REGIc, _REG0_, _REGIc, _REG0_,
102 _REGIc, _REG0_, _null_, _null_, _REGIc, _REG0_, _REGIc, _REG0_,
103 _REGI_, _NONE_, _null_, _NONE_, _REGIi, _REGIc, _REGIp, _NONE_,
104 _REGI_, _NONE_, _REGIc, _null_, _REGIi, _REGIc, _REGIp, _null_,
105 _REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_,
106 _REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_
107 };
108
109 #else
110
111 static unsigned char const type_table[64] = {
112 _REGI_, _NONE_, _null_, _null_, _REGIi, _REGi_, _REGIp, _null_,
113 _REGI_, _REGIn, _null_, _null_, _REGIi, _null_, _REGIp, _null_,
114 _REGIc, _NONE_, _null_, _null_, _null_, _REG0_, _null_, _null_,
115 _REGIc, _null_, _null_, _null_, _null_, _REG0_, _REGIc, _null_,
116 _REGI_, _NONE_, _null_, _NONE_, _REGIi, _REGIc, _REGIp, _NONE_,
117 _REGI_, _NONE_, _REGIc, _null_, _REGIi, _REGIc, _REGIp, _null_,
118 _REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_,
119 _REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_
120 };
121
122 #endif NO_UNDOC_CODE
123
124
125
126
127 unsigned char FPU_rm;
128 char FPU_st0_tag;
129 FPU_REG *FPU_st0_ptr;
130
131
132 unsigned long FPU_entry_op_cs;
133 unsigned short FPU_data_selector;
134
135
136 #ifdef PARANOID
137 char emulating=0;
138 #endif PARANOID
139
140 static int valid_prefix(unsigned char *Byte, unsigned char **fpu_eip,
141 overrides *override);
142
143
144 asmlinkage void math_emulate(long arg)
145 {
146 unsigned char FPU_modrm, byte1;
147 unsigned short code;
148 fpu_addr_modes addr_modes;
149 int unmasked;
150
151 #ifdef PARANOID
152 if ( emulating )
153 {
154 printk("ERROR: wm-FPU-emu is not RE-ENTRANT!\n");
155 }
156 RE_ENTRANT_CHECK_ON;
157 #endif PARANOID
158
159 if (!current->used_math)
160 {
161 int i;
162 for ( i = 0; i < 8; i++ )
163 {
164
165
166 regs[i].exp = 0;
167 regs[i].sigh = 0x80000000;
168 }
169 finit();
170 current->used_math = 1;
171 }
172
173 SETUP_DATA_AREA(arg);
174
175 addr_modes.vm86 = (FPU_EFLAGS & 0x00020000) != 0;
176
177 if ( addr_modes.vm86 )
178 FPU_EIP += FPU_CS << 4;
179
180 FPU_ORIG_EIP = FPU_EIP;
181
182 if ( !addr_modes.vm86 )
183 {
184
185 if (FPU_CS == KERNEL_CS)
186 {
187 printk("math_emulate: %04x:%08lx\n",FPU_CS,FPU_EIP);
188 panic("Math emulation needed in kernel");
189 }
190
191
192 if (FPU_CS != USER_CS || FPU_DS != USER_DS)
193 {
194 math_abort(FPU_info,SIGILL);
195 }
196 }
197
198 FPU_lookahead = 1;
199 if (current->flags & PF_PTRACED)
200 FPU_lookahead = 0;
201
202 if ( !valid_prefix(&byte1, (unsigned char **)&FPU_EIP,
203 &addr_modes.override) )
204 {
205 RE_ENTRANT_CHECK_OFF;
206 printk("FPU emulator: Unknown prefix byte 0x%02x, probably due to\n"
207 "FPU emulator: self-modifying code! (emulation impossible)\n",
208 byte1);
209 RE_ENTRANT_CHECK_ON;
210 EXCEPTION(EX_INTERNAL|0x126);
211 math_abort(FPU_info,SIGILL);
212 }
213
214 do_another_FPU_instruction:
215
216 FPU_EIP++;
217
218 #ifdef PECULIAR_486
219
220
221
222 FPU_data_selector = FPU_DS;
223 #endif PECULIAR_486
224
225 if ( (byte1 & 0xf8) != 0xd8 )
226 {
227 if ( byte1 == FWAIT_OPCODE )
228 {
229 if (partial_status & SW_Summary)
230 goto do_the_FPU_interrupt;
231 else
232 goto FPU_fwait_done;
233 }
234 #ifdef PARANOID
235 EXCEPTION(EX_INTERNAL|0x128);
236 math_abort(FPU_info,SIGILL);
237 #endif PARANOID
238 }
239
240 RE_ENTRANT_CHECK_OFF;
241 FPU_code_verify_area(1);
242 FPU_modrm = get_fs_byte((unsigned short *) FPU_EIP);
243 RE_ENTRANT_CHECK_ON;
244 FPU_EIP++;
245
246 if (partial_status & SW_Summary)
247 {
248
249
250
251
252
253
254 code = (FPU_modrm << 8) | byte1;
255 if ( ! ( (((code & 0xf803) == 0xe003) ||
256 (((code & 0x3003) == 0x3001) &&
257
258 ((code & 0xc000) != 0xc000))) ) )
259 {
260
261
262
263
264
265
266
267
268 do_the_FPU_interrupt:
269 cs_selector &= 0xffff0000;
270 cs_selector |= status_word();
271 operand_selector = tag_word();
272 partial_status = 0;
273 top = 0;
274 {
275 int r;
276 for (r = 0; r < 8; r++)
277 {
278 regs[r].tag = TW_Empty;
279 }
280 }
281
282 RE_ENTRANT_CHECK_OFF;
283 current->tss.trap_no = 16;
284 current->tss.error_code = 0;
285 send_sig(SIGFPE, current, 1);
286 return;
287 }
288 }
289
290 FPU_entry_eip = FPU_ORIG_EIP;
291
292 FPU_entry_op_cs = (byte1 << 24) | (FPU_modrm << 16) | (FPU_CS & 0xffff) ;
293
294 FPU_rm = FPU_modrm & 7;
295
296 if ( FPU_modrm < 0300 )
297 {
298
299 if ( addr_modes.vm86
300 ^ (addr_modes.override.address_size == ADDR_SIZE_PREFIX) )
301 get_address_16(FPU_modrm, &FPU_EIP, addr_modes);
302 else
303 get_address(FPU_modrm, &FPU_EIP, addr_modes);
304 if ( !(byte1 & 1) )
305 {
306 unsigned short status1 = partial_status;
307 FPU_st0_ptr = &st(0);
308 FPU_st0_tag = FPU_st0_ptr->tag;
309
310
311 if ( NOT_EMPTY_0 )
312 {
313 unmasked = 0;
314 switch ( (byte1 >> 1) & 3 )
315 {
316 case 0:
317 unmasked = reg_load_single();
318 break;
319 case 1:
320 reg_load_int32();
321 break;
322 case 2:
323 unmasked = reg_load_double();
324 break;
325 case 3:
326 reg_load_int16();
327 break;
328 }
329
330
331
332 FPU_st0_ptr = &st(0);
333 FPU_st0_tag = FPU_st0_ptr->tag;
334
335
336
337
338 if ( (FPU_st0_tag == TW_NaN) ||
339 (FPU_loaded_data.tag == TW_NaN) )
340 {
341
342
343 partial_status = status1;
344 if ( (FPU_modrm & 0x30) == 0x10 )
345 {
346
347 EXCEPTION(EX_Invalid);
348 setcc(SW_C3 | SW_C2 | SW_C0);
349 if ( (FPU_modrm & 0x08) && (control_word & CW_Invalid) )
350 pop();
351 }
352 else
353 {
354 #ifdef PECULIAR_486
355
356
357 if ( (FPU_modrm & 0x28) == 0x20 )
358
359 real_2op_NaN(&FPU_loaded_data, FPU_st0_ptr,
360 FPU_st0_ptr);
361 else
362 #endif PECULIAR_486
363
364 real_2op_NaN(FPU_st0_ptr, &FPU_loaded_data,
365 FPU_st0_ptr);
366 }
367 goto reg_mem_instr_done;
368 }
369
370 if ( unmasked && !((FPU_modrm & 0x30) == 0x10) )
371 {
372
373 if ( (FPU_modrm & 0x38) == 0x38 )
374 {
375
376 if ( (FPU_st0_tag == TW_Zero) &&
377 (FPU_loaded_data.tag == TW_Valid) )
378 {
379 if ( divide_by_zero(FPU_loaded_data.sign,
380 FPU_st0_ptr) )
381 {
382
383
384
385
386 partial_status &= ~SW_Denorm_Op;
387 partial_status |= status1 & SW_Denorm_Op;
388 }
389 }
390 }
391 goto reg_mem_instr_done;
392 }
393
394 switch ( (FPU_modrm >> 3) & 7 )
395 {
396 case 0:
397 clear_C1();
398 reg_add(FPU_st0_ptr, &FPU_loaded_data, FPU_st0_ptr,
399 control_word);
400 break;
401 case 1:
402 clear_C1();
403 reg_mul(FPU_st0_ptr, &FPU_loaded_data, FPU_st0_ptr,
404 control_word);
405 break;
406 case 2:
407 compare_st_data();
408 break;
409 case 3:
410 if ( !compare_st_data() && !unmasked )
411 pop();
412 break;
413 case 4:
414 clear_C1();
415 reg_sub(FPU_st0_ptr, &FPU_loaded_data, FPU_st0_ptr,
416 control_word);
417 break;
418 case 5:
419 clear_C1();
420 reg_sub(&FPU_loaded_data, FPU_st0_ptr, FPU_st0_ptr,
421 control_word);
422 break;
423 case 6:
424 clear_C1();
425 reg_div(FPU_st0_ptr, &FPU_loaded_data, FPU_st0_ptr,
426 control_word);
427 break;
428 case 7:
429 clear_C1();
430 if ( FPU_st0_tag == TW_Zero )
431 partial_status = status1;
432
433 reg_div(&FPU_loaded_data, FPU_st0_ptr, FPU_st0_ptr,
434 control_word);
435 break;
436 }
437 }
438 else
439 {
440 if ( (FPU_modrm & 0x30) == 0x10 )
441 {
442
443 EXCEPTION(EX_StackUnder);
444 setcc(SW_C3 | SW_C2 | SW_C0);
445 if ( (FPU_modrm & 0x08) && (control_word & CW_Invalid) )
446 pop();
447 }
448 else
449 stack_underflow();
450 }
451 }
452 else
453 {
454 load_store_instr(((FPU_modrm & 0x38) | (byte1 & 6)) >> 1,
455 addr_modes);
456 }
457
458 reg_mem_instr_done:
459
460 #ifndef PECULIAR_486
461 *(unsigned short *)&operand_selector = FPU_data_selector;
462 #endif PECULIAR_486
463 ;
464 }
465 else
466 {
467
468 unsigned char instr_index = (FPU_modrm & 0x38) | (byte1 & 7);
469
470 #ifdef PECULIAR_486
471
472
473 FPU_data_address = 0;
474 #endif PECULIAR_486
475
476 FPU_st0_ptr = &st(0);
477 FPU_st0_tag = FPU_st0_ptr->tag;
478 switch ( type_table[(int) instr_index] )
479 {
480 case _NONE_:
481 break;
482 case _REG0_:
483 if ( !NOT_EMPTY_0 )
484 {
485 stack_underflow();
486 goto FPU_instruction_done;
487 }
488 break;
489 case _REGIi:
490 if ( !NOT_EMPTY_0 || !NOT_EMPTY(FPU_rm) )
491 {
492 stack_underflow_i(FPU_rm);
493 goto FPU_instruction_done;
494 }
495 break;
496 case _REGIp:
497 if ( !NOT_EMPTY_0 || !NOT_EMPTY(FPU_rm) )
498 {
499 stack_underflow_pop(FPU_rm);
500 goto FPU_instruction_done;
501 }
502 break;
503 case _REGI_:
504 if ( !NOT_EMPTY_0 || !NOT_EMPTY(FPU_rm) )
505 {
506 stack_underflow();
507 goto FPU_instruction_done;
508 }
509 break;
510 case _PUSH_:
511 break;
512 case _null_:
513 FPU_illegal();
514 goto FPU_instruction_done;
515 default:
516 EXCEPTION(EX_INTERNAL|0x111);
517 goto FPU_instruction_done;
518 }
519 (*st_instr_table[(int) instr_index])();
520 }
521
522 FPU_instruction_done:
523
524 ip_offset = FPU_entry_eip;
525 cs_selector = FPU_entry_op_cs;
526 data_operand_offset = (unsigned long)FPU_data_address;
527 #ifdef PECULIAR_486
528 *(unsigned short *)&operand_selector = FPU_data_selector;
529 #endif PECULIAR_486
530
531 FPU_fwait_done:
532
533 #ifdef DEBUG
534 RE_ENTRANT_CHECK_OFF;
535 emu_printall();
536 RE_ENTRANT_CHECK_ON;
537 #endif DEBUG
538
539 if (FPU_lookahead && !need_resched)
540 {
541 FPU_ORIG_EIP = FPU_EIP;
542 if ( valid_prefix(&byte1, (unsigned char **)&FPU_EIP,
543 &addr_modes.override) )
544 goto do_another_FPU_instruction;
545 }
546
547 if ( addr_modes.vm86 )
548 FPU_EIP -= FPU_CS << 4;
549
550 RE_ENTRANT_CHECK_OFF;
551 }
552
553
554
555
556
557
558 static int valid_prefix(unsigned char *Byte, unsigned char **fpu_eip,
559 overrides *override)
560 {
561 unsigned char byte;
562 unsigned char *ip = *fpu_eip;
563
564 *override = (overrides) { 0, 0, PREFIX_DS_ };
565
566 RE_ENTRANT_CHECK_OFF;
567 FPU_code_verify_area(1);
568 byte = get_fs_byte(ip);
569 RE_ENTRANT_CHECK_ON;
570
571 while ( 1 )
572 {
573 switch ( byte )
574 {
575 case ADDR_SIZE_PREFIX:
576 override->address_size = ADDR_SIZE_PREFIX;
577 goto do_next_byte;
578
579 case OP_SIZE_PREFIX:
580 override->operand_size = OP_SIZE_PREFIX;
581 goto do_next_byte;
582
583 case PREFIX_CS:
584 override->segment = PREFIX_CS_;
585 goto do_next_byte;
586 case PREFIX_ES:
587 override->segment = PREFIX_ES_;
588 goto do_next_byte;
589 case PREFIX_SS:
590 override->segment = PREFIX_SS_;
591 goto do_next_byte;
592 case PREFIX_FS:
593 override->segment = PREFIX_FS_;
594 goto do_next_byte;
595 case PREFIX_GS:
596 override->segment = PREFIX_GS_;
597 goto do_next_byte;
598
599 case PREFIX_DS:
600 override->segment = PREFIX_DS_;
601
602
603
604
605
606
607 case PREFIX_REPE:
608 case PREFIX_REPNE:
609
610 do_next_byte:
611 ip++;
612 RE_ENTRANT_CHECK_OFF;
613 FPU_code_verify_area(1);
614 byte = get_fs_byte(ip);
615 RE_ENTRANT_CHECK_ON;
616 break;
617 case FWAIT_OPCODE:
618 *Byte = byte;
619 return 1;
620 default:
621 if ( (byte & 0xf8) == 0xd8 )
622 {
623 *Byte = byte;
624 *fpu_eip = ip;
625 return 1;
626 }
627 else
628 {
629
630
631 *Byte = byte;
632 return 0;
633 }
634 }
635 }
636 }
637
638
639 void math_abort(struct info * info, unsigned int signal)
640 {
641 FPU_EIP = FPU_ORIG_EIP;
642 current->tss.trap_no = 16;
643 current->tss.error_code = 0;
644 send_sig(signal,current,1);
645 RE_ENTRANT_CHECK_OFF;
646 __asm__("movl %0,%%esp ; ret": :"g" (((long) info)-4));
647 #ifdef PARANOID
648 printk("ERROR: wm-FPU-emu math_abort failed!\n");
649 #endif PARANOID
650 }