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1da177e4 LT |
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/ptrace.h> | |
29 | ||
30 | #include <asm/uaccess.h> | |
31 | #include <asm/desc.h> | |
32 | ||
33 | #include "fpu_system.h" | |
34 | #include "fpu_emu.h" | |
35 | #include "exception.h" | |
36 | #include "control_w.h" | |
37 | #include "status_w.h" | |
38 | ||
3d0d14f9 | 39 | #define __BAD__ FPU_illegal /* Illegal on an 80486, causes SIGILL */ |
1da177e4 | 40 | |
3d0d14f9 | 41 | #ifndef NO_UNDOC_CODE /* Un-documented FPU op-codes supported by default. */ |
1da177e4 LT |
42 | |
43 | /* WARNING: These codes are not documented by Intel in their 80486 manual | |
44 | and may not work on FPU clones or later Intel FPUs. */ | |
45 | ||
46 | /* Changes to support the un-doc codes provided by Linus Torvalds. */ | |
47 | ||
3d0d14f9 IM |
48 | #define _d9_d8_ fstp_i /* unofficial code (19) */ |
49 | #define _dc_d0_ fcom_st /* unofficial code (14) */ | |
50 | #define _dc_d8_ fcompst /* unofficial code (1c) */ | |
51 | #define _dd_c8_ fxch_i /* unofficial code (0d) */ | |
52 | #define _de_d0_ fcompst /* unofficial code (16) */ | |
53 | #define _df_c0_ ffreep /* unofficial code (07) ffree + pop */ | |
54 | #define _df_c8_ fxch_i /* unofficial code (0f) */ | |
55 | #define _df_d0_ fstp_i /* unofficial code (17) */ | |
56 | #define _df_d8_ fstp_i /* unofficial code (1f) */ | |
1da177e4 LT |
57 | |
58 | static FUNC const st_instr_table[64] = { | |
3d0d14f9 IM |
59 | fadd__, fld_i_, __BAD__, __BAD__, fadd_i, ffree_, faddp_, _df_c0_, |
60 | fmul__, fxch_i, __BAD__, __BAD__, fmul_i, _dd_c8_, fmulp_, _df_c8_, | |
61 | fcom_st, fp_nop, __BAD__, __BAD__, _dc_d0_, fst_i_, _de_d0_, _df_d0_, | |
62 | fcompst, _d9_d8_, __BAD__, __BAD__, _dc_d8_, fstp_i, fcompp, _df_d8_, | |
63 | fsub__, FPU_etc, __BAD__, finit_, fsubri, fucom_, fsubrp, fstsw_, | |
64 | fsubr_, fconst, fucompp, __BAD__, fsub_i, fucomp, fsubp_, __BAD__, | |
65 | fdiv__, FPU_triga, __BAD__, __BAD__, fdivri, __BAD__, fdivrp, __BAD__, | |
66 | fdivr_, FPU_trigb, __BAD__, __BAD__, fdiv_i, __BAD__, fdivp_, __BAD__, | |
1da177e4 LT |
67 | }; |
68 | ||
3d0d14f9 | 69 | #else /* Support only documented FPU op-codes */ |
1da177e4 LT |
70 | |
71 | static FUNC const st_instr_table[64] = { | |
3d0d14f9 IM |
72 | fadd__, fld_i_, __BAD__, __BAD__, fadd_i, ffree_, faddp_, __BAD__, |
73 | fmul__, fxch_i, __BAD__, __BAD__, fmul_i, __BAD__, fmulp_, __BAD__, | |
74 | fcom_st, fp_nop, __BAD__, __BAD__, __BAD__, fst_i_, __BAD__, __BAD__, | |
75 | fcompst, __BAD__, __BAD__, __BAD__, __BAD__, fstp_i, fcompp, __BAD__, | |
76 | fsub__, FPU_etc, __BAD__, finit_, fsubri, fucom_, fsubrp, fstsw_, | |
77 | fsubr_, fconst, fucompp, __BAD__, fsub_i, fucomp, fsubp_, __BAD__, | |
78 | fdiv__, FPU_triga, __BAD__, __BAD__, fdivri, __BAD__, fdivrp, __BAD__, | |
79 | fdivr_, FPU_trigb, __BAD__, __BAD__, fdiv_i, __BAD__, fdivp_, __BAD__, | |
1da177e4 LT |
80 | }; |
81 | ||
82 | #endif /* NO_UNDOC_CODE */ | |
83 | ||
3d0d14f9 IM |
84 | #define _NONE_ 0 /* Take no special action */ |
85 | #define _REG0_ 1 /* Need to check for not empty st(0) */ | |
86 | #define _REGI_ 2 /* Need to check for not empty st(0) and st(rm) */ | |
87 | #define _REGi_ 0 /* Uses st(rm) */ | |
88 | #define _PUSH_ 3 /* Need to check for space to push onto stack */ | |
89 | #define _null_ 4 /* Function illegal or not implemented */ | |
90 | #define _REGIi 5 /* Uses st(0) and st(rm), result to st(rm) */ | |
91 | #define _REGIp 6 /* Uses st(0) and st(rm), result to st(rm) then pop */ | |
92 | #define _REGIc 0 /* Compare st(0) and st(rm) */ | |
93 | #define _REGIn 0 /* Uses st(0) and st(rm), but handle checks later */ | |
1da177e4 LT |
94 | |
95 | #ifndef NO_UNDOC_CODE | |
96 | ||
97 | /* Un-documented FPU op-codes supported by default. (see above) */ | |
98 | ||
99 | static u_char const type_table[64] = { | |
3d0d14f9 IM |
100 | _REGI_, _NONE_, _null_, _null_, _REGIi, _REGi_, _REGIp, _REGi_, |
101 | _REGI_, _REGIn, _null_, _null_, _REGIi, _REGI_, _REGIp, _REGI_, | |
102 | _REGIc, _NONE_, _null_, _null_, _REGIc, _REG0_, _REGIc, _REG0_, | |
103 | _REGIc, _REG0_, _null_, _null_, _REGIc, _REG0_, _REGIc, _REG0_, | |
104 | _REGI_, _NONE_, _null_, _NONE_, _REGIi, _REGIc, _REGIp, _NONE_, | |
105 | _REGI_, _NONE_, _REGIc, _null_, _REGIi, _REGIc, _REGIp, _null_, | |
106 | _REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_, | |
107 | _REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_ | |
1da177e4 LT |
108 | }; |
109 | ||
3d0d14f9 | 110 | #else /* Support only documented FPU op-codes */ |
1da177e4 LT |
111 | |
112 | static u_char const type_table[64] = { | |
3d0d14f9 IM |
113 | _REGI_, _NONE_, _null_, _null_, _REGIi, _REGi_, _REGIp, _null_, |
114 | _REGI_, _REGIn, _null_, _null_, _REGIi, _null_, _REGIp, _null_, | |
115 | _REGIc, _NONE_, _null_, _null_, _null_, _REG0_, _null_, _null_, | |
116 | _REGIc, _null_, _null_, _null_, _null_, _REG0_, _REGIc, _null_, | |
117 | _REGI_, _NONE_, _null_, _NONE_, _REGIi, _REGIc, _REGIp, _NONE_, | |
118 | _REGI_, _NONE_, _REGIc, _null_, _REGIi, _REGIc, _REGIp, _null_, | |
119 | _REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_, | |
120 | _REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_ | |
1da177e4 LT |
121 | }; |
122 | ||
123 | #endif /* NO_UNDOC_CODE */ | |
124 | ||
1da177e4 | 125 | #ifdef RE_ENTRANT_CHECKING |
3d0d14f9 | 126 | u_char emulating = 0; |
1da177e4 LT |
127 | #endif /* RE_ENTRANT_CHECKING */ |
128 | ||
e8d591dc | 129 | static int valid_prefix(u_char *Byte, u_char __user ** fpu_eip, |
3d0d14f9 | 130 | overrides * override); |
1da177e4 LT |
131 | |
132 | asmlinkage void math_emulate(long arg) | |
133 | { | |
3d0d14f9 IM |
134 | u_char FPU_modrm, byte1; |
135 | unsigned short code; | |
136 | fpu_addr_modes addr_modes; | |
137 | int unmasked; | |
138 | FPU_REG loaded_data; | |
139 | FPU_REG *st0_ptr; | |
140 | u_char loaded_tag, st0_tag; | |
141 | void __user *data_address; | |
142 | struct address data_sel_off; | |
143 | struct address entry_sel_off; | |
144 | unsigned long code_base = 0; | |
145 | unsigned long code_limit = 0; /* Initialized to stop compiler warnings */ | |
146 | struct desc_struct code_descriptor; | |
1da177e4 LT |
147 | |
148 | #ifdef RE_ENTRANT_CHECKING | |
3d0d14f9 IM |
149 | if (emulating) { |
150 | printk("ERROR: wm-FPU-emu is not RE-ENTRANT!\n"); | |
151 | } | |
152 | RE_ENTRANT_CHECK_ON; | |
1da177e4 LT |
153 | #endif /* RE_ENTRANT_CHECKING */ |
154 | ||
3d0d14f9 IM |
155 | if (!used_math()) { |
156 | finit(); | |
157 | set_used_math(); | |
1da177e4 LT |
158 | } |
159 | ||
3d0d14f9 IM |
160 | SETUP_DATA_AREA(arg); |
161 | ||
162 | FPU_ORIG_EIP = FPU_EIP; | |
163 | ||
164 | if ((FPU_EFLAGS & 0x00020000) != 0) { | |
165 | /* Virtual 8086 mode */ | |
166 | addr_modes.default_mode = VM86; | |
167 | FPU_EIP += code_base = FPU_CS << 4; | |
168 | code_limit = code_base + 0xffff; /* Assumes code_base <= 0xffff0000 */ | |
169 | } else if (FPU_CS == __USER_CS && FPU_DS == __USER_DS) { | |
170 | addr_modes.default_mode = 0; | |
171 | } else if (FPU_CS == __KERNEL_CS) { | |
172 | printk("math_emulate: %04x:%08lx\n", FPU_CS, FPU_EIP); | |
173 | panic("Math emulation needed in kernel"); | |
174 | } else { | |
175 | ||
176 | if ((FPU_CS & 4) != 4) { /* Must be in the LDT */ | |
177 | /* Can only handle segmented addressing via the LDT | |
178 | for now, and it must be 16 bit */ | |
179 | printk("FPU emulator: Unsupported addressing mode\n"); | |
180 | math_abort(FPU_info, SIGILL); | |
181 | } | |
182 | ||
183 | code_descriptor = LDT_DESCRIPTOR(FPU_CS); | |
184 | if (SEG_D_SIZE(code_descriptor)) { | |
185 | /* The above test may be wrong, the book is not clear */ | |
186 | /* Segmented 32 bit protected mode */ | |
187 | addr_modes.default_mode = SEG32; | |
188 | } else { | |
189 | /* 16 bit protected mode */ | |
190 | addr_modes.default_mode = PM16; | |
191 | } | |
192 | FPU_EIP += code_base = SEG_BASE_ADDR(code_descriptor); | |
193 | code_limit = code_base | |
194 | + (SEG_LIMIT(code_descriptor) + | |
195 | 1) * SEG_GRANULARITY(code_descriptor) | |
196 | - 1; | |
197 | if (code_limit < code_base) | |
198 | code_limit = 0xffffffff; | |
1da177e4 | 199 | } |
3d0d14f9 IM |
200 | |
201 | FPU_lookahead = 1; | |
202 | if (current->ptrace & PT_PTRACED) | |
203 | FPU_lookahead = 0; | |
204 | ||
205 | if (!valid_prefix(&byte1, (u_char __user **) & FPU_EIP, | |
206 | &addr_modes.override)) { | |
207 | RE_ENTRANT_CHECK_OFF; | |
208 | printk | |
209 | ("FPU emulator: Unknown prefix byte 0x%02x, probably due to\n" | |
210 | "FPU emulator: self-modifying code! (emulation impossible)\n", | |
211 | byte1); | |
212 | RE_ENTRANT_CHECK_ON; | |
213 | EXCEPTION(EX_INTERNAL | 0x126); | |
214 | math_abort(FPU_info, SIGILL); | |
1da177e4 | 215 | } |
3d0d14f9 IM |
216 | |
217 | do_another_FPU_instruction: | |
218 | ||
219 | no_ip_update = 0; | |
220 | ||
221 | FPU_EIP++; /* We have fetched the prefix and first code bytes. */ | |
222 | ||
223 | if (addr_modes.default_mode) { | |
224 | /* This checks for the minimum instruction bytes. | |
225 | We also need to check any extra (address mode) code access. */ | |
226 | if (FPU_EIP > code_limit) | |
227 | math_abort(FPU_info, SIGSEGV); | |
1da177e4 | 228 | } |
3d0d14f9 IM |
229 | |
230 | if ((byte1 & 0xf8) != 0xd8) { | |
231 | if (byte1 == FWAIT_OPCODE) { | |
232 | if (partial_status & SW_Summary) | |
233 | goto do_the_FPU_interrupt; | |
234 | else | |
235 | goto FPU_fwait_done; | |
236 | } | |
1da177e4 | 237 | #ifdef PARANOID |
3d0d14f9 IM |
238 | EXCEPTION(EX_INTERNAL | 0x128); |
239 | math_abort(FPU_info, SIGILL); | |
1da177e4 | 240 | #endif /* PARANOID */ |
1da177e4 LT |
241 | } |
242 | ||
3d0d14f9 IM |
243 | RE_ENTRANT_CHECK_OFF; |
244 | FPU_code_access_ok(1); | |
245 | FPU_get_user(FPU_modrm, (u_char __user *) FPU_EIP); | |
246 | RE_ENTRANT_CHECK_ON; | |
247 | FPU_EIP++; | |
248 | ||
249 | if (partial_status & SW_Summary) { | |
250 | /* Ignore the error for now if the current instruction is a no-wait | |
251 | control instruction */ | |
252 | /* The 80486 manual contradicts itself on this topic, | |
253 | but a real 80486 uses the following instructions: | |
254 | fninit, fnstenv, fnsave, fnstsw, fnstenv, fnclex. | |
255 | */ | |
256 | code = (FPU_modrm << 8) | byte1; | |
257 | if (!((((code & 0xf803) == 0xe003) || /* fnclex, fninit, fnstsw */ | |
258 | (((code & 0x3003) == 0x3001) && /* fnsave, fnstcw, fnstenv, | |
259 | fnstsw */ | |
260 | ((code & 0xc000) != 0xc000))))) { | |
261 | /* | |
262 | * We need to simulate the action of the kernel to FPU | |
263 | * interrupts here. | |
264 | */ | |
265 | do_the_FPU_interrupt: | |
266 | ||
267 | FPU_EIP = FPU_ORIG_EIP; /* Point to current FPU instruction. */ | |
268 | ||
269 | RE_ENTRANT_CHECK_OFF; | |
270 | current->thread.trap_no = 16; | |
271 | current->thread.error_code = 0; | |
272 | send_sig(SIGFPE, current, 1); | |
273 | return; | |
1da177e4 | 274 | } |
3d0d14f9 | 275 | } |
1da177e4 | 276 | |
3d0d14f9 IM |
277 | entry_sel_off.offset = FPU_ORIG_EIP; |
278 | entry_sel_off.selector = FPU_CS; | |
279 | entry_sel_off.opcode = (byte1 << 8) | FPU_modrm; | |
1da177e4 | 280 | |
3d0d14f9 | 281 | FPU_rm = FPU_modrm & 7; |
1da177e4 | 282 | |
3d0d14f9 IM |
283 | if (FPU_modrm < 0300) { |
284 | /* All of these instructions use the mod/rm byte to get a data address */ | |
1da177e4 | 285 | |
3d0d14f9 IM |
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); | |
1da177e4 | 299 | } |
3d0d14f9 IM |
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 | } | |
1da177e4 | 498 | } |
1da177e4 | 499 | |
3d0d14f9 IM |
500 | } else { |
501 | /* None of these instructions access user memory */ | |
502 | u_char instr_index = (FPU_modrm & 0x38) | (byte1 & 7); | |
1da177e4 LT |
503 | |
504 | #ifdef PECULIAR_486 | |
3d0d14f9 IM |
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; | |
1da177e4 LT |
509 | #endif /* PECULIAR_486 */ |
510 | ||
3d0d14f9 IM |
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]) (); | |
1da177e4 | 550 | |
3d0d14f9 IM |
551 | FPU_instruction_done: |
552 | ; | |
553 | } | |
1da177e4 | 554 | |
3d0d14f9 IM |
555 | if (!no_ip_update) |
556 | instruction_address = entry_sel_off; | |
1da177e4 | 557 | |
3d0d14f9 | 558 | FPU_fwait_done: |
1da177e4 LT |
559 | |
560 | #ifdef DEBUG | |
3d0d14f9 IM |
561 | RE_ENTRANT_CHECK_OFF; |
562 | FPU_printall(); | |
563 | RE_ENTRANT_CHECK_ON; | |
1da177e4 LT |
564 | #endif /* DEBUG */ |
565 | ||
3d0d14f9 IM |
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 | } | |
1da177e4 | 572 | |
3d0d14f9 IM |
573 | if (addr_modes.default_mode) |
574 | FPU_EIP -= code_base; | |
1da177e4 | 575 | |
3d0d14f9 | 576 | RE_ENTRANT_CHECK_OFF; |
1da177e4 LT |
577 | } |
578 | ||
1da177e4 LT |
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. */ | |
e8d591dc | 583 | static int valid_prefix(u_char *Byte, u_char __user **fpu_eip, |
3d0d14f9 | 584 | overrides * override) |
1da177e4 | 585 | { |
3d0d14f9 IM |
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; | |
1da177e4 LT |
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 | ||
3d0d14f9 IM |
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 | } | |
1da177e4 | 656 | } |
1da177e4 LT |
657 | } |
658 | ||
3d0d14f9 | 659 | void math_abort(struct info *info, unsigned int signal) |
1da177e4 LT |
660 | { |
661 | FPU_EIP = FPU_ORIG_EIP; | |
662 | current->thread.trap_no = 16; | |
663 | current->thread.error_code = 0; | |
3d0d14f9 | 664 | send_sig(signal, current, 1); |
1da177e4 | 665 | RE_ENTRANT_CHECK_OFF; |
3d0d14f9 | 666 | __asm__("movl %0,%%esp ; ret": :"g"(((long)info) - 4)); |
1da177e4 | 667 | #ifdef PARANOID |
3d0d14f9 | 668 | printk("ERROR: wm-FPU-emu math_abort failed!\n"); |
1da177e4 LT |
669 | #endif /* PARANOID */ |
670 | } | |
671 | ||
1da177e4 LT |
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 | ||
e8d591dc | 676 | int restore_i387_soft(void *s387, struct _fpstate __user *buf) |
1da177e4 | 677 | { |
3d0d14f9 IM |
678 | u_char __user *d = (u_char __user *) buf; |
679 | int offset, other, i, tags, regnr, tag, newtop; | |
680 | ||
681 | RE_ENTRANT_CHECK_OFF; | |
682 | FPU_access_ok(VERIFY_READ, d, 7 * 4 + 8 * 10); | |
683 | if (__copy_from_user(&S387->cwd, d, 7 * 4)) | |
684 | return -1; | |
685 | RE_ENTRANT_CHECK_ON; | |
686 | ||
687 | d += 7 * 4; | |
688 | ||
689 | S387->ftop = (S387->swd >> SW_Top_Shift) & 7; | |
690 | offset = (S387->ftop & 7) * 10; | |
691 | other = 80 - offset; | |
692 | ||
693 | RE_ENTRANT_CHECK_OFF; | |
694 | /* Copy all registers in stack order. */ | |
695 | if (__copy_from_user(((u_char *) & S387->st_space) + offset, d, other)) | |
696 | return -1; | |
697 | if (offset) | |
698 | if (__copy_from_user | |
699 | ((u_char *) & S387->st_space, d + other, offset)) | |
700 | return -1; | |
701 | RE_ENTRANT_CHECK_ON; | |
702 | ||
703 | /* The tags may need to be corrected now. */ | |
704 | tags = S387->twd; | |
705 | newtop = S387->ftop; | |
706 | for (i = 0; i < 8; i++) { | |
707 | regnr = (i + newtop) & 7; | |
708 | if (((tags >> ((regnr & 7) * 2)) & 3) != TAG_Empty) { | |
709 | /* The loaded data over-rides all other cases. */ | |
710 | tag = | |
711 | FPU_tagof((FPU_REG *) ((u_char *) S387->st_space + | |
712 | 10 * regnr)); | |
713 | tags &= ~(3 << (regnr * 2)); | |
714 | tags |= (tag & 3) << (regnr * 2); | |
715 | } | |
1da177e4 | 716 | } |
3d0d14f9 | 717 | S387->twd = tags; |
1da177e4 | 718 | |
3d0d14f9 | 719 | return 0; |
1da177e4 LT |
720 | } |
721 | ||
1da177e4 LT |
722 | int save_i387_soft(void *s387, struct _fpstate __user * buf) |
723 | { | |
3d0d14f9 IM |
724 | u_char __user *d = (u_char __user *) buf; |
725 | int offset = (S387->ftop & 7) * 10, other = 80 - offset; | |
1da177e4 | 726 | |
3d0d14f9 IM |
727 | RE_ENTRANT_CHECK_OFF; |
728 | FPU_access_ok(VERIFY_WRITE, d, 7 * 4 + 8 * 10); | |
1da177e4 | 729 | #ifdef PECULIAR_486 |
3d0d14f9 IM |
730 | S387->cwd &= ~0xe080; |
731 | /* An 80486 sets nearly all of the reserved bits to 1. */ | |
732 | S387->cwd |= 0xffff0040; | |
733 | S387->swd = sstatus_word() | 0xffff0000; | |
734 | S387->twd |= 0xffff0000; | |
735 | S387->fcs &= ~0xf8000000; | |
736 | S387->fos |= 0xffff0000; | |
1da177e4 | 737 | #endif /* PECULIAR_486 */ |
3d0d14f9 IM |
738 | if (__copy_to_user(d, &S387->cwd, 7 * 4)) |
739 | return -1; | |
740 | RE_ENTRANT_CHECK_ON; | |
741 | ||
742 | d += 7 * 4; | |
743 | ||
744 | RE_ENTRANT_CHECK_OFF; | |
745 | /* Copy all registers in stack order. */ | |
746 | if (__copy_to_user(d, ((u_char *) & S387->st_space) + offset, other)) | |
747 | return -1; | |
748 | if (offset) | |
749 | if (__copy_to_user | |
750 | (d + other, (u_char *) & S387->st_space, offset)) | |
751 | return -1; | |
752 | RE_ENTRANT_CHECK_ON; | |
753 | ||
754 | return 1; | |
1da177e4 | 755 | } |