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[linux-2.6/sactl.git] / arch / x86 / math-emu / fpu_entry.c
blob6e38d877ea7725fb8d94d2c91a0ee7daab2585d1
1 /*---------------------------------------------------------------------------+
2 | fpu_entry.c |
3 | |
4 | The entry functions for wm-FPU-emu |
5 | |
6 | Copyright (C) 1992,1993,1994,1996,1997 |
7 | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
8 | E-mail billm@suburbia.net |
9 | |
10 | See the files "README" and "COPYING" for further copyright and warranty |
11 | information. |
12 | |
13 +---------------------------------------------------------------------------*/
14
15 /*---------------------------------------------------------------------------+
16 | Note: |
17 | The file contains code which accesses user memory. |
18 | Emulator static data may change when user memory is accessed, due to |
19 | other processes using the emulator while swapping is in progress. |
20 +---------------------------------------------------------------------------*/
21
22 /*---------------------------------------------------------------------------+
23 | math_emulate(), restore_i387_soft() and save_i387_soft() are the only |
24 | entry points for wm-FPU-emu. |
25 +---------------------------------------------------------------------------*/
26
27 #include <linux/signal.h>
28 #include <linux/regset.h>
29
30 #include <asm/uaccess.h>
31 #include <asm/desc.h>
32 #include <asm/user.h>
33
34 #include "fpu_system.h"
35 #include "fpu_emu.h"
36 #include "exception.h"
37 #include "control_w.h"
38 #include "status_w.h"
39
40 #define __BAD__ FPU_illegal /* Illegal on an 80486, causes SIGILL */
41
42 #ifndef NO_UNDOC_CODE /* Un-documented FPU op-codes supported by default. */
43
44 /* WARNING: These codes are not documented by Intel in their 80486 manual
45 and may not work on FPU clones or later Intel FPUs. */
46
47 /* Changes to support the un-doc codes provided by Linus Torvalds. */
48
49 #define _d9_d8_ fstp_i /* unofficial code (19) */
50 #define _dc_d0_ fcom_st /* unofficial code (14) */
51 #define _dc_d8_ fcompst /* unofficial code (1c) */
52 #define _dd_c8_ fxch_i /* unofficial code (0d) */
53 #define _de_d0_ fcompst /* unofficial code (16) */
54 #define _df_c0_ ffreep /* unofficial code (07) ffree + pop */
55 #define _df_c8_ fxch_i /* unofficial code (0f) */
56 #define _df_d0_ fstp_i /* unofficial code (17) */
57 #define _df_d8_ fstp_i /* unofficial code (1f) */
58
59 static FUNC const st_instr_table[64] = {
60 fadd__, fld_i_, __BAD__, __BAD__, fadd_i, ffree_, faddp_, _df_c0_,
61 fmul__, fxch_i, __BAD__, __BAD__, fmul_i, _dd_c8_, fmulp_, _df_c8_,
62 fcom_st, fp_nop, __BAD__, __BAD__, _dc_d0_, fst_i_, _de_d0_, _df_d0_,
63 fcompst, _d9_d8_, __BAD__, __BAD__, _dc_d8_, fstp_i, fcompp, _df_d8_,
64 fsub__, FPU_etc, __BAD__, finit_, fsubri, fucom_, fsubrp, fstsw_,
65 fsubr_, fconst, fucompp, __BAD__, fsub_i, fucomp, fsubp_, __BAD__,
66 fdiv__, FPU_triga, __BAD__, __BAD__, fdivri, __BAD__, fdivrp, __BAD__,
67 fdivr_, FPU_trigb, __BAD__, __BAD__, fdiv_i, __BAD__, fdivp_, __BAD__,
68 };
69
70 #else /* Support only documented FPU op-codes */
71
72 static FUNC const st_instr_table[64] = {
73 fadd__, fld_i_, __BAD__, __BAD__, fadd_i, ffree_, faddp_, __BAD__,
74 fmul__, fxch_i, __BAD__, __BAD__, fmul_i, __BAD__, fmulp_, __BAD__,
75 fcom_st, fp_nop, __BAD__, __BAD__, __BAD__, fst_i_, __BAD__, __BAD__,
76 fcompst, __BAD__, __BAD__, __BAD__, __BAD__, fstp_i, fcompp, __BAD__,
77 fsub__, FPU_etc, __BAD__, finit_, fsubri, fucom_, fsubrp, fstsw_,
78 fsubr_, fconst, fucompp, __BAD__, fsub_i, fucomp, fsubp_, __BAD__,
79 fdiv__, FPU_triga, __BAD__, __BAD__, fdivri, __BAD__, fdivrp, __BAD__,
80 fdivr_, FPU_trigb, __BAD__, __BAD__, fdiv_i, __BAD__, fdivp_, __BAD__,
81 };
82
83 #endif /* NO_UNDOC_CODE */
84
85 #define _NONE_ 0 /* Take no special action */
86 #define _REG0_ 1 /* Need to check for not empty st(0) */
87 #define _REGI_ 2 /* Need to check for not empty st(0) and st(rm) */
88 #define _REGi_ 0 /* Uses st(rm) */
89 #define _PUSH_ 3 /* Need to check for space to push onto stack */
90 #define _null_ 4 /* Function illegal or not implemented */
91 #define _REGIi 5 /* Uses st(0) and st(rm), result to st(rm) */
92 #define _REGIp 6 /* Uses st(0) and st(rm), result to st(rm) then pop */
93 #define _REGIc 0 /* Compare st(0) and st(rm) */
94 #define _REGIn 0 /* Uses st(0) and st(rm), but handle checks later */
95
96 #ifndef NO_UNDOC_CODE
97
98 /* Un-documented FPU op-codes supported by default. (see above) */
99
100 static u_char const type_table[64] = {
101 _REGI_, _NONE_, _null_, _null_, _REGIi, _REGi_, _REGIp, _REGi_,
102 _REGI_, _REGIn, _null_, _null_, _REGIi, _REGI_, _REGIp, _REGI_,
103 _REGIc, _NONE_, _null_, _null_, _REGIc, _REG0_, _REGIc, _REG0_,
104 _REGIc, _REG0_, _null_, _null_, _REGIc, _REG0_, _REGIc, _REG0_,
105 _REGI_, _NONE_, _null_, _NONE_, _REGIi, _REGIc, _REGIp, _NONE_,
106 _REGI_, _NONE_, _REGIc, _null_, _REGIi, _REGIc, _REGIp, _null_,
107 _REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_,
108 _REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_
109 };
110
111 #else /* Support only documented FPU op-codes */
112
113 static u_char const type_table[64] = {
114 _REGI_, _NONE_, _null_, _null_, _REGIi, _REGi_, _REGIp, _null_,
115 _REGI_, _REGIn, _null_, _null_, _REGIi, _null_, _REGIp, _null_,
116 _REGIc, _NONE_, _null_, _null_, _null_, _REG0_, _null_, _null_,
117 _REGIc, _null_, _null_, _null_, _null_, _REG0_, _REGIc, _null_,
118 _REGI_, _NONE_, _null_, _NONE_, _REGIi, _REGIc, _REGIp, _NONE_,
119 _REGI_, _NONE_, _REGIc, _null_, _REGIi, _REGIc, _REGIp, _null_,
120 _REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_,
121 _REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_
122 };
123
124 #endif /* NO_UNDOC_CODE */
125
126 #ifdef RE_ENTRANT_CHECKING
127 u_char emulating = 0;
128 #endif /* RE_ENTRANT_CHECKING */
129
130 static int valid_prefix(u_char *Byte, u_char __user ** fpu_eip,
131 overrides * override);
132
133 asmlinkage void math_emulate(long arg)
134 {
135 u_char FPU_modrm, byte1;
136 unsigned short code;
137 fpu_addr_modes addr_modes;
138 int unmasked;
139 FPU_REG loaded_data;
140 FPU_REG *st0_ptr;
141 u_char loaded_tag, st0_tag;
142 void __user *data_address;
143 struct address data_sel_off;
144 struct address entry_sel_off;
145 unsigned long code_base = 0;
146 unsigned long code_limit = 0; /* Initialized to stop compiler warnings */
147 struct desc_struct code_descriptor;
148
149 #ifdef RE_ENTRANT_CHECKING
150 if (emulating) {
151 printk("ERROR: wm-FPU-emu is not RE-ENTRANT!\n");
152 }
153 RE_ENTRANT_CHECK_ON;
154 #endif /* RE_ENTRANT_CHECKING */
155
156 if (!used_math()) {
157 finit();
158 set_used_math();
159 }
160
161 SETUP_DATA_AREA(arg);
162
163 FPU_ORIG_EIP = FPU_EIP;
164
165 if ((FPU_EFLAGS & 0x00020000) != 0) {
166 /* Virtual 8086 mode */
167 addr_modes.default_mode = VM86;
168 FPU_EIP += code_base = FPU_CS << 4;
169 code_limit = code_base + 0xffff; /* Assumes code_base <= 0xffff0000 */
170 } else if (FPU_CS == __USER_CS && FPU_DS == __USER_DS) {
171 addr_modes.default_mode = 0;
172 } else if (FPU_CS == __KERNEL_CS) {
173 printk("math_emulate: %04x:%08lx\n", FPU_CS, FPU_EIP);
174 panic("Math emulation needed in kernel");
175 } else {
176
177 if ((FPU_CS & 4) != 4) { /* Must be in the LDT */
178 /* Can only handle segmented addressing via the LDT
179 for now, and it must be 16 bit */
180 printk("FPU emulator: Unsupported addressing mode\n");
181 math_abort(FPU_info, SIGILL);
182 }
183
184 code_descriptor = LDT_DESCRIPTOR(FPU_CS);
185 if (SEG_D_SIZE(code_descriptor)) {
186 /* The above test may be wrong, the book is not clear */
187 /* Segmented 32 bit protected mode */
188 addr_modes.default_mode = SEG32;
189 } else {
190 /* 16 bit protected mode */
191 addr_modes.default_mode = PM16;
192 }
193 FPU_EIP += code_base = SEG_BASE_ADDR(code_descriptor);
194 code_limit = code_base
195 + (SEG_LIMIT(code_descriptor) +
196 1) * SEG_GRANULARITY(code_descriptor)
197 - 1;
198 if (code_limit < code_base)
199 code_limit = 0xffffffff;
200 }
201
202 FPU_lookahead = !(FPU_EFLAGS & X86_EFLAGS_TF);
203
204 if (!valid_prefix(&byte1, (u_char __user **) & FPU_EIP,
205 &addr_modes.override)) {
206 RE_ENTRANT_CHECK_OFF;
207 printk
208 ("FPU emulator: Unknown prefix byte 0x%02x, probably due to\n"
209 "FPU emulator: self-modifying code! (emulation impossible)\n",
210 byte1);
211 RE_ENTRANT_CHECK_ON;
212 EXCEPTION(EX_INTERNAL | 0x126);
213 math_abort(FPU_info, SIGILL);
214 }
215
216 do_another_FPU_instruction:
217
218 no_ip_update = 0;
219
220 FPU_EIP++; /* We have fetched the prefix and first code bytes. */
221
222 if (addr_modes.default_mode) {
223 /* This checks for the minimum instruction bytes.
224 We also need to check any extra (address mode) code access. */
225 if (FPU_EIP > code_limit)
226 math_abort(FPU_info, SIGSEGV);
227 }
228
229 if ((byte1 & 0xf8) != 0xd8) {
230 if (byte1 == FWAIT_OPCODE) {
231 if (partial_status & SW_Summary)
232 goto do_the_FPU_interrupt;
233 else
234 goto FPU_fwait_done;
235 }
236 #ifdef PARANOID
237 EXCEPTION(EX_INTERNAL | 0x128);
238 math_abort(FPU_info, SIGILL);
239 #endif /* PARANOID */
240 }
241
242 RE_ENTRANT_CHECK_OFF;
243 FPU_code_access_ok(1);
244 FPU_get_user(FPU_modrm, (u_char __user *) FPU_EIP);
245 RE_ENTRANT_CHECK_ON;
246 FPU_EIP++;
247
248 if (partial_status & SW_Summary) {
249 /* Ignore the error for now if the current instruction is a no-wait
250 control instruction */
251 /* The 80486 manual contradicts itself on this topic,
252 but a real 80486 uses the following instructions:
253 fninit, fnstenv, fnsave, fnstsw, fnstenv, fnclex.
254 */
255 code = (FPU_modrm << 8) | byte1;
256 if (!((((code & 0xf803) == 0xe003) || /* fnclex, fninit, fnstsw */
257 (((code & 0x3003) == 0x3001) && /* fnsave, fnstcw, fnstenv,
258 fnstsw */
259 ((code & 0xc000) != 0xc000))))) {
260 /*
261 * We need to simulate the action of the kernel to FPU
262 * interrupts here.
263 */
264 do_the_FPU_interrupt:
265
266 FPU_EIP = FPU_ORIG_EIP; /* Point to current FPU instruction. */
267
268 RE_ENTRANT_CHECK_OFF;
269 current->thread.trap_no = 16;
270 current->thread.error_code = 0;
271 send_sig(SIGFPE, current, 1);
272 return;
273 }
274 }
275
276 entry_sel_off.offset = FPU_ORIG_EIP;
277 entry_sel_off.selector = FPU_CS;
278 entry_sel_off.opcode = (byte1 << 8) | FPU_modrm;
279 entry_sel_off.empty = 0;
280
281 FPU_rm = FPU_modrm & 7;
282
283 if (FPU_modrm < 0300) {
284 /* All of these instructions use the mod/rm byte to get a data address */
285
286 if ((addr_modes.default_mode & SIXTEEN)
287 ^ (addr_modes.override.address_size == ADDR_SIZE_PREFIX))
288 data_address =
289 FPU_get_address_16(FPU_modrm, &FPU_EIP,
290 &data_sel_off, addr_modes);
291 else
292 data_address =
293 FPU_get_address(FPU_modrm, &FPU_EIP, &data_sel_off,
294 addr_modes);
295
296 if (addr_modes.default_mode) {
297 if (FPU_EIP - 1 > code_limit)
298 math_abort(FPU_info, SIGSEGV);
299 }
300
301 if (!(byte1 & 1)) {
302 unsigned short status1 = partial_status;
303
304 st0_ptr = &st(0);
305 st0_tag = FPU_gettag0();
306
307 /* Stack underflow has priority */
308 if (NOT_EMPTY_ST0) {
309 if (addr_modes.default_mode & PROTECTED) {
310 /* This table works for 16 and 32 bit protected mode */
311 if (access_limit <
312 data_sizes_16[(byte1 >> 1) & 3])
313 math_abort(FPU_info, SIGSEGV);
314 }
315
316 unmasked = 0; /* Do this here to stop compiler warnings. */
317 switch ((byte1 >> 1) & 3) {
318 case 0:
319 unmasked =
320 FPU_load_single((float __user *)
321 data_address,
322 &loaded_data);
323 loaded_tag = unmasked & 0xff;
324 unmasked &= ~0xff;
325 break;
326 case 1:
327 loaded_tag =
328 FPU_load_int32((long __user *)
329 data_address,
330 &loaded_data);
331 break;
332 case 2:
333 unmasked =
334 FPU_load_double((double __user *)
335 data_address,
336 &loaded_data);
337 loaded_tag = unmasked & 0xff;
338 unmasked &= ~0xff;
339 break;
340 case 3:
341 default: /* Used here to suppress gcc warnings. */
342 loaded_tag =
343 FPU_load_int16((short __user *)
344 data_address,
345 &loaded_data);
346 break;
347 }
348
349 /* No more access to user memory, it is safe
350 to use static data now */
351
352 /* NaN operands have the next priority. */
353 /* We have to delay looking at st(0) until after
354 loading the data, because that data might contain an SNaN */
355 if (((st0_tag == TAG_Special) && isNaN(st0_ptr))
356 || ((loaded_tag == TAG_Special)
357 && isNaN(&loaded_data))) {
358 /* Restore the status word; we might have loaded a
359 denormal. */
360 partial_status = status1;
361 if ((FPU_modrm & 0x30) == 0x10) {
362 /* fcom or fcomp */
363 EXCEPTION(EX_Invalid);
364 setcc(SW_C3 | SW_C2 | SW_C0);
365 if ((FPU_modrm & 0x08)
366 && (control_word &
367 CW_Invalid))
368 FPU_pop(); /* fcomp, masked, so we pop. */
369 } else {
370 if (loaded_tag == TAG_Special)
371 loaded_tag =
372 FPU_Special
373 (&loaded_data);
374 #ifdef PECULIAR_486
375 /* This is not really needed, but gives behaviour
376 identical to an 80486 */
377 if ((FPU_modrm & 0x28) == 0x20)
378 /* fdiv or fsub */
379 real_2op_NaN
380 (&loaded_data,
381 loaded_tag, 0,
382 &loaded_data);
383 else
384 #endif /* PECULIAR_486 */
385 /* fadd, fdivr, fmul, or fsubr */
386 real_2op_NaN
387 (&loaded_data,
388 loaded_tag, 0,
389 st0_ptr);
390 }
391 goto reg_mem_instr_done;
392 }
393
394 if (unmasked && !((FPU_modrm & 0x30) == 0x10)) {
395 /* Is not a comparison instruction. */
396 if ((FPU_modrm & 0x38) == 0x38) {
397 /* fdivr */
398 if ((st0_tag == TAG_Zero) &&
399 ((loaded_tag == TAG_Valid)
400 || (loaded_tag ==
401 TAG_Special
402 &&
403 isdenormal
404 (&loaded_data)))) {
405 if (FPU_divide_by_zero
406 (0,
407 getsign
408 (&loaded_data))
409 < 0) {
410 /* We use the fact here that the unmasked
411 exception in the loaded data was for a
412 denormal operand */
413 /* Restore the state of the denormal op bit */
414 partial_status
415 &=
416 ~SW_Denorm_Op;
417 partial_status
418 |=
419 status1 &
420 SW_Denorm_Op;
421 } else
422 setsign(st0_ptr,
423 getsign
424 (&loaded_data));
425 }
426 }
427 goto reg_mem_instr_done;
428 }
429
430 switch ((FPU_modrm >> 3) & 7) {
431 case 0: /* fadd */
432 clear_C1();
433 FPU_add(&loaded_data, loaded_tag, 0,
434 control_word);
435 break;
436 case 1: /* fmul */
437 clear_C1();
438 FPU_mul(&loaded_data, loaded_tag, 0,
439 control_word);
440 break;
441 case 2: /* fcom */
442 FPU_compare_st_data(&loaded_data,
443 loaded_tag);
444 break;
445 case 3: /* fcomp */
446 if (!FPU_compare_st_data
447 (&loaded_data, loaded_tag)
448 && !unmasked)
449 FPU_pop();
450 break;
451 case 4: /* fsub */
452 clear_C1();
453 FPU_sub(LOADED | loaded_tag,
454 (int)&loaded_data,
455 control_word);
456 break;
457 case 5: /* fsubr */
458 clear_C1();
459 FPU_sub(REV | LOADED | loaded_tag,
460 (int)&loaded_data,
461 control_word);
462 break;
463 case 6: /* fdiv */
464 clear_C1();
465 FPU_div(LOADED | loaded_tag,
466 (int)&loaded_data,
467 control_word);
468 break;
469 case 7: /* fdivr */
470 clear_C1();
471 if (st0_tag == TAG_Zero)
472 partial_status = status1; /* Undo any denorm tag,
473 zero-divide has priority. */
474 FPU_div(REV | LOADED | loaded_tag,
475 (int)&loaded_data,
476 control_word);
477 break;
478 }
479 } else {
480 if ((FPU_modrm & 0x30) == 0x10) {
481 /* The instruction is fcom or fcomp */
482 EXCEPTION(EX_StackUnder);
483 setcc(SW_C3 | SW_C2 | SW_C0);
484 if ((FPU_modrm & 0x08)
485 && (control_word & CW_Invalid))
486 FPU_pop(); /* fcomp */
487 } else
488 FPU_stack_underflow();
489 }
490 reg_mem_instr_done:
491 operand_address = data_sel_off;
492 } else {
493 if (!(no_ip_update =
494 FPU_load_store(((FPU_modrm & 0x38) | (byte1 & 6))
495 >> 1, addr_modes, data_address))) {
496 operand_address = data_sel_off;
497 }
498 }
499
500 } else {
501 /* None of these instructions access user memory */
502 u_char instr_index = (FPU_modrm & 0x38) | (byte1 & 7);
503
504 #ifdef PECULIAR_486
505 /* This is supposed to be undefined, but a real 80486 seems
506 to do this: */
507 operand_address.offset = 0;
508 operand_address.selector = FPU_DS;
509 #endif /* PECULIAR_486 */
510
511 st0_ptr = &st(0);
512 st0_tag = FPU_gettag0();
513 switch (type_table[(int)instr_index]) {
514 case _NONE_: /* also _REGIc: _REGIn */
515 break;
516 case _REG0_:
517 if (!NOT_EMPTY_ST0) {
518 FPU_stack_underflow();
519 goto FPU_instruction_done;
520 }
521 break;
522 case _REGIi:
523 if (!NOT_EMPTY_ST0 || !NOT_EMPTY(FPU_rm)) {
524 FPU_stack_underflow_i(FPU_rm);
525 goto FPU_instruction_done;
526 }
527 break;
528 case _REGIp:
529 if (!NOT_EMPTY_ST0 || !NOT_EMPTY(FPU_rm)) {
530 FPU_stack_underflow_pop(FPU_rm);
531 goto FPU_instruction_done;
532 }
533 break;
534 case _REGI_:
535 if (!NOT_EMPTY_ST0 || !NOT_EMPTY(FPU_rm)) {
536 FPU_stack_underflow();
537 goto FPU_instruction_done;
538 }
539 break;
540 case _PUSH_: /* Only used by the fld st(i) instruction */
541 break;
542 case _null_:
543 FPU_illegal();
544 goto FPU_instruction_done;
545 default:
546 EXCEPTION(EX_INTERNAL | 0x111);
547 goto FPU_instruction_done;
548 }
549 (*st_instr_table[(int)instr_index]) ();
550
551 FPU_instruction_done:
552 ;
553 }
554
555 if (!no_ip_update)
556 instruction_address = entry_sel_off;
557
558 FPU_fwait_done:
559
560 #ifdef DEBUG
561 RE_ENTRANT_CHECK_OFF;
562 FPU_printall();
563 RE_ENTRANT_CHECK_ON;
564 #endif /* DEBUG */
565
566 if (FPU_lookahead && !need_resched()) {
567 FPU_ORIG_EIP = FPU_EIP - code_base;
568 if (valid_prefix(&byte1, (u_char __user **) & FPU_EIP,
569 &addr_modes.override))
570 goto do_another_FPU_instruction;
571 }
572
573 if (addr_modes.default_mode)
574 FPU_EIP -= code_base;
575
576 RE_ENTRANT_CHECK_OFF;
577 }
578
579 /* Support for prefix bytes is not yet complete. To properly handle
580 all prefix bytes, further changes are needed in the emulator code
581 which accesses user address space. Access to separate segments is
582 important for msdos emulation. */
583 static int valid_prefix(u_char *Byte, u_char __user **fpu_eip,
584 overrides * override)
585 {
586 u_char byte;
587 u_char __user *ip = *fpu_eip;
588
589 *override = (overrides) {
590 0, 0, PREFIX_DEFAULT}; /* defaults */
591
592 RE_ENTRANT_CHECK_OFF;
593 FPU_code_access_ok(1);
594 FPU_get_user(byte, ip);
595 RE_ENTRANT_CHECK_ON;
596
597 while (1) {
598 switch (byte) {
599 case ADDR_SIZE_PREFIX:
600 override->address_size = ADDR_SIZE_PREFIX;
601 goto do_next_byte;
602
603 case OP_SIZE_PREFIX:
604 override->operand_size = OP_SIZE_PREFIX;
605 goto do_next_byte;
606
607 case PREFIX_CS:
608 override->segment = PREFIX_CS_;
609 goto do_next_byte;
610 case PREFIX_ES:
611 override->segment = PREFIX_ES_;
612 goto do_next_byte;
613 case PREFIX_SS:
614 override->segment = PREFIX_SS_;
615 goto do_next_byte;
616 case PREFIX_FS:
617 override->segment = PREFIX_FS_;
618 goto do_next_byte;
619 case PREFIX_GS:
620 override->segment = PREFIX_GS_;
621 goto do_next_byte;
622 case PREFIX_DS:
623 override->segment = PREFIX_DS_;
624 goto do_next_byte;
625
626 /* lock is not a valid prefix for FPU instructions,
627 let the cpu handle it to generate a SIGILL. */
628 /* case PREFIX_LOCK: */
629
630 /* rep.. prefixes have no meaning for FPU instructions */
631 case PREFIX_REPE:
632 case PREFIX_REPNE:
633
634 do_next_byte:
635 ip++;
636 RE_ENTRANT_CHECK_OFF;
637 FPU_code_access_ok(1);
638 FPU_get_user(byte, ip);
639 RE_ENTRANT_CHECK_ON;
640 break;
641 case FWAIT_OPCODE:
642 *Byte = byte;
643 return 1;
644 default:
645 if ((byte & 0xf8) == 0xd8) {
646 *Byte = byte;
647 *fpu_eip = ip;
648 return 1;
649 } else {
650 /* Not a valid sequence of prefix bytes followed by
651 an FPU instruction. */
652 *Byte = byte; /* Needed for error message. */
653 return 0;
654 }
655 }
656 }
657 }
658
659 void math_abort(struct info *info, unsigned int signal)
660 {
661 FPU_EIP = FPU_ORIG_EIP;
662 current->thread.trap_no = 16;
663 current->thread.error_code = 0;
664 send_sig(signal, current, 1);
665 RE_ENTRANT_CHECK_OFF;
666 __asm__("movl %0,%%esp ; ret": :"g"(((long)info) - 4));
667 #ifdef PARANOID
668 printk("ERROR: wm-FPU-emu math_abort failed!\n");
669 #endif /* PARANOID */
670 }
671
672 #define S387 ((struct i387_soft_struct *)s387)
673 #define sstatus_word() \
674 ((S387->swd & ~SW_Top & 0xffff) | ((S387->ftop << SW_Top_Shift) & SW_Top))
675
676 int fpregs_soft_set(struct task_struct *target,
677 const struct user_regset *regset,
678 unsigned int pos, unsigned int count,
679 const void *kbuf, const void __user *ubuf)
680 {
681 struct i387_soft_struct *s387 = &target->thread.xstate->soft;
682 void *space = s387->st_space;
683 int ret;
684 int offset, other, i, tags, regnr, tag, newtop;
685
686 RE_ENTRANT_CHECK_OFF;
687 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, s387, 0,
688 offsetof(struct i387_soft_struct, st_space));
689 RE_ENTRANT_CHECK_ON;
690
691 if (ret)
692 return ret;
693
694 S387->ftop = (S387->swd >> SW_Top_Shift) & 7;
695 offset = (S387->ftop & 7) * 10;
696 other = 80 - offset;
697
698 RE_ENTRANT_CHECK_OFF;
699
700 /* Copy all registers in stack order. */
701 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
702 space + offset, 0, other);
703 if (!ret && offset)
704 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
705 space, 0, offset);
706
707 RE_ENTRANT_CHECK_ON;
708
709 /* The tags may need to be corrected now. */
710 tags = S387->twd;
711 newtop = S387->ftop;
712 for (i = 0; i < 8; i++) {
713 regnr = (i + newtop) & 7;
714 if (((tags >> ((regnr & 7) * 2)) & 3) != TAG_Empty) {
715 /* The loaded data over-rides all other cases. */
716 tag =
717 FPU_tagof((FPU_REG *) ((u_char *) S387->st_space +
718 10 * regnr));
719 tags &= ~(3 << (regnr * 2));
720 tags |= (tag & 3) << (regnr * 2);
721 }
722 }
723 S387->twd = tags;
724
725 return ret;
726 }
727
728 int fpregs_soft_get(struct task_struct *target,
729 const struct user_regset *regset,
730 unsigned int pos, unsigned int count,
731 void *kbuf, void __user *ubuf)
732 {
733 struct i387_soft_struct *s387 = &target->thread.xstate->soft;
734 const void *space = s387->st_space;
735 int ret;
736 int offset = (S387->ftop & 7) * 10, other = 80 - offset;
737
738 RE_ENTRANT_CHECK_OFF;
739
740 #ifdef PECULIAR_486
741 S387->cwd &= ~0xe080;
742 /* An 80486 sets nearly all of the reserved bits to 1. */
743 S387->cwd |= 0xffff0040;
744 S387->swd = sstatus_word() | 0xffff0000;
745 S387->twd |= 0xffff0000;
746 S387->fcs &= ~0xf8000000;
747 S387->fos |= 0xffff0000;
748 #endif /* PECULIAR_486 */
749
750 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, s387, 0,
751 offsetof(struct i387_soft_struct, st_space));
752
753 /* Copy all registers in stack order. */
754 if (!ret)
755 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
756 space + offset, 0, other);
757 if (!ret)
758 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
759 space, 0, offset);
760
761 RE_ENTRANT_CHECK_ON;
762
763 return ret;
764 }
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