Merge master.kernel.org:/home/rmk/linux-2.6-arm
[linux-2.6] / arch / x86 / kernel / i387_32.c
1 /*
2  *  Copyright (C) 1994 Linus Torvalds
3  *
4  *  Pentium III FXSR, SSE support
5  *  General FPU state handling cleanups
6  *      Gareth Hughes <gareth@valinux.com>, May 2000
7  */
8
9 #include <linux/sched.h>
10 #include <linux/module.h>
11 #include <asm/processor.h>
12 #include <asm/i387.h>
13 #include <asm/math_emu.h>
14 #include <asm/sigcontext.h>
15 #include <asm/user.h>
16 #include <asm/ptrace.h>
17 #include <asm/uaccess.h>
18
19 #ifdef CONFIG_MATH_EMULATION
20 #define HAVE_HWFP (boot_cpu_data.hard_math)
21 #else
22 #define HAVE_HWFP 1
23 #endif
24
25 static unsigned long mxcsr_feature_mask __read_mostly = 0xffffffff;
26
27 void mxcsr_feature_mask_init(void)
28 {
29         unsigned long mask = 0;
30         clts();
31         if (cpu_has_fxsr) {
32                 memset(&current->thread.i387.fxsave, 0, sizeof(struct i387_fxsave_struct));
33                 asm volatile("fxsave %0" : : "m" (current->thread.i387.fxsave)); 
34                 mask = current->thread.i387.fxsave.mxcsr_mask;
35                 if (mask == 0) mask = 0x0000ffbf;
36         } 
37         mxcsr_feature_mask &= mask;
38         stts();
39 }
40
41 /*
42  * The _current_ task is using the FPU for the first time
43  * so initialize it and set the mxcsr to its default
44  * value at reset if we support XMM instructions and then
45  * remeber the current task has used the FPU.
46  */
47 void init_fpu(struct task_struct *tsk)
48 {
49         if (cpu_has_fxsr) {
50                 memset(&tsk->thread.i387.fxsave, 0, sizeof(struct i387_fxsave_struct));
51                 tsk->thread.i387.fxsave.cwd = 0x37f;
52                 if (cpu_has_xmm)
53                         tsk->thread.i387.fxsave.mxcsr = 0x1f80;
54         } else {
55                 memset(&tsk->thread.i387.fsave, 0, sizeof(struct i387_fsave_struct));
56                 tsk->thread.i387.fsave.cwd = 0xffff037fu;
57                 tsk->thread.i387.fsave.swd = 0xffff0000u;
58                 tsk->thread.i387.fsave.twd = 0xffffffffu;
59                 tsk->thread.i387.fsave.fos = 0xffff0000u;
60         }
61         /* only the device not available exception or ptrace can call init_fpu */
62         set_stopped_child_used_math(tsk);
63 }
64
65 /*
66  * FPU lazy state save handling.
67  */
68
69 void kernel_fpu_begin(void)
70 {
71         struct thread_info *thread = current_thread_info();
72
73         preempt_disable();
74         if (thread->status & TS_USEDFPU) {
75                 __save_init_fpu(thread->task);
76                 return;
77         }
78         clts();
79 }
80 EXPORT_SYMBOL_GPL(kernel_fpu_begin);
81
82 /*
83  * FPU tag word conversions.
84  */
85
86 static inline unsigned short twd_i387_to_fxsr( unsigned short twd )
87 {
88         unsigned int tmp; /* to avoid 16 bit prefixes in the code */
89  
90         /* Transform each pair of bits into 01 (valid) or 00 (empty) */
91         tmp = ~twd;
92         tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */
93         /* and move the valid bits to the lower byte. */
94         tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */
95         tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */
96         tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */
97         return tmp;
98 }
99
100 static inline unsigned long twd_fxsr_to_i387( struct i387_fxsave_struct *fxsave )
101 {
102         struct _fpxreg *st = NULL;
103         unsigned long tos = (fxsave->swd >> 11) & 7;
104         unsigned long twd = (unsigned long) fxsave->twd;
105         unsigned long tag;
106         unsigned long ret = 0xffff0000u;
107         int i;
108
109 #define FPREG_ADDR(f, n)        ((void *)&(f)->st_space + (n) * 16);
110
111         for ( i = 0 ; i < 8 ; i++ ) {
112                 if ( twd & 0x1 ) {
113                         st = FPREG_ADDR( fxsave, (i - tos) & 7 );
114
115                         switch ( st->exponent & 0x7fff ) {
116                         case 0x7fff:
117                                 tag = 2;                /* Special */
118                                 break;
119                         case 0x0000:
120                                 if ( !st->significand[0] &&
121                                      !st->significand[1] &&
122                                      !st->significand[2] &&
123                                      !st->significand[3] ) {
124                                         tag = 1;        /* Zero */
125                                 } else {
126                                         tag = 2;        /* Special */
127                                 }
128                                 break;
129                         default:
130                                 if ( st->significand[3] & 0x8000 ) {
131                                         tag = 0;        /* Valid */
132                                 } else {
133                                         tag = 2;        /* Special */
134                                 }
135                                 break;
136                         }
137                 } else {
138                         tag = 3;                        /* Empty */
139                 }
140                 ret |= (tag << (2 * i));
141                 twd = twd >> 1;
142         }
143         return ret;
144 }
145
146 /*
147  * FPU state interaction.
148  */
149
150 unsigned short get_fpu_cwd( struct task_struct *tsk )
151 {
152         if ( cpu_has_fxsr ) {
153                 return tsk->thread.i387.fxsave.cwd;
154         } else {
155                 return (unsigned short)tsk->thread.i387.fsave.cwd;
156         }
157 }
158
159 unsigned short get_fpu_swd( struct task_struct *tsk )
160 {
161         if ( cpu_has_fxsr ) {
162                 return tsk->thread.i387.fxsave.swd;
163         } else {
164                 return (unsigned short)tsk->thread.i387.fsave.swd;
165         }
166 }
167
168 #if 0
169 unsigned short get_fpu_twd( struct task_struct *tsk )
170 {
171         if ( cpu_has_fxsr ) {
172                 return tsk->thread.i387.fxsave.twd;
173         } else {
174                 return (unsigned short)tsk->thread.i387.fsave.twd;
175         }
176 }
177 #endif  /*  0  */
178
179 unsigned short get_fpu_mxcsr( struct task_struct *tsk )
180 {
181         if ( cpu_has_xmm ) {
182                 return tsk->thread.i387.fxsave.mxcsr;
183         } else {
184                 return 0x1f80;
185         }
186 }
187
188 #if 0
189
190 void set_fpu_cwd( struct task_struct *tsk, unsigned short cwd )
191 {
192         if ( cpu_has_fxsr ) {
193                 tsk->thread.i387.fxsave.cwd = cwd;
194         } else {
195                 tsk->thread.i387.fsave.cwd = ((long)cwd | 0xffff0000u);
196         }
197 }
198
199 void set_fpu_swd( struct task_struct *tsk, unsigned short swd )
200 {
201         if ( cpu_has_fxsr ) {
202                 tsk->thread.i387.fxsave.swd = swd;
203         } else {
204                 tsk->thread.i387.fsave.swd = ((long)swd | 0xffff0000u);
205         }
206 }
207
208 void set_fpu_twd( struct task_struct *tsk, unsigned short twd )
209 {
210         if ( cpu_has_fxsr ) {
211                 tsk->thread.i387.fxsave.twd = twd_i387_to_fxsr(twd);
212         } else {
213                 tsk->thread.i387.fsave.twd = ((long)twd | 0xffff0000u);
214         }
215 }
216
217 #endif  /*  0  */
218
219 /*
220  * FXSR floating point environment conversions.
221  */
222
223 static int convert_fxsr_to_user( struct _fpstate __user *buf,
224                                         struct i387_fxsave_struct *fxsave )
225 {
226         unsigned long env[7];
227         struct _fpreg __user *to;
228         struct _fpxreg *from;
229         int i;
230
231         env[0] = (unsigned long)fxsave->cwd | 0xffff0000ul;
232         env[1] = (unsigned long)fxsave->swd | 0xffff0000ul;
233         env[2] = twd_fxsr_to_i387(fxsave);
234         env[3] = fxsave->fip;
235         env[4] = fxsave->fcs | ((unsigned long)fxsave->fop << 16);
236         env[5] = fxsave->foo;
237         env[6] = fxsave->fos;
238
239         if ( __copy_to_user( buf, env, 7 * sizeof(unsigned long) ) )
240                 return 1;
241
242         to = &buf->_st[0];
243         from = (struct _fpxreg *) &fxsave->st_space[0];
244         for ( i = 0 ; i < 8 ; i++, to++, from++ ) {
245                 unsigned long __user *t = (unsigned long __user *)to;
246                 unsigned long *f = (unsigned long *)from;
247
248                 if (__put_user(*f, t) ||
249                                 __put_user(*(f + 1), t + 1) ||
250                                 __put_user(from->exponent, &to->exponent))
251                         return 1;
252         }
253         return 0;
254 }
255
256 static int convert_fxsr_from_user( struct i387_fxsave_struct *fxsave,
257                                           struct _fpstate __user *buf )
258 {
259         unsigned long env[7];
260         struct _fpxreg *to;
261         struct _fpreg __user *from;
262         int i;
263
264         if ( __copy_from_user( env, buf, 7 * sizeof(long) ) )
265                 return 1;
266
267         fxsave->cwd = (unsigned short)(env[0] & 0xffff);
268         fxsave->swd = (unsigned short)(env[1] & 0xffff);
269         fxsave->twd = twd_i387_to_fxsr((unsigned short)(env[2] & 0xffff));
270         fxsave->fip = env[3];
271         fxsave->fop = (unsigned short)((env[4] & 0xffff0000ul) >> 16);
272         fxsave->fcs = (env[4] & 0xffff);
273         fxsave->foo = env[5];
274         fxsave->fos = env[6];
275
276         to = (struct _fpxreg *) &fxsave->st_space[0];
277         from = &buf->_st[0];
278         for ( i = 0 ; i < 8 ; i++, to++, from++ ) {
279                 unsigned long *t = (unsigned long *)to;
280                 unsigned long __user *f = (unsigned long __user *)from;
281
282                 if (__get_user(*t, f) ||
283                                 __get_user(*(t + 1), f + 1) ||
284                                 __get_user(to->exponent, &from->exponent))
285                         return 1;
286         }
287         return 0;
288 }
289
290 /*
291  * Signal frame handlers.
292  */
293
294 static inline int save_i387_fsave( struct _fpstate __user *buf )
295 {
296         struct task_struct *tsk = current;
297
298         unlazy_fpu( tsk );
299         tsk->thread.i387.fsave.status = tsk->thread.i387.fsave.swd;
300         if ( __copy_to_user( buf, &tsk->thread.i387.fsave,
301                              sizeof(struct i387_fsave_struct) ) )
302                 return -1;
303         return 1;
304 }
305
306 static int save_i387_fxsave( struct _fpstate __user *buf )
307 {
308         struct task_struct *tsk = current;
309         int err = 0;
310
311         unlazy_fpu( tsk );
312
313         if ( convert_fxsr_to_user( buf, &tsk->thread.i387.fxsave ) )
314                 return -1;
315
316         err |= __put_user( tsk->thread.i387.fxsave.swd, &buf->status );
317         err |= __put_user( X86_FXSR_MAGIC, &buf->magic );
318         if ( err )
319                 return -1;
320
321         if ( __copy_to_user( &buf->_fxsr_env[0], &tsk->thread.i387.fxsave,
322                              sizeof(struct i387_fxsave_struct) ) )
323                 return -1;
324         return 1;
325 }
326
327 int save_i387( struct _fpstate __user *buf )
328 {
329         if ( !used_math() )
330                 return 0;
331
332         /* This will cause a "finit" to be triggered by the next
333          * attempted FPU operation by the 'current' process.
334          */
335         clear_used_math();
336
337         if ( HAVE_HWFP ) {
338                 if ( cpu_has_fxsr ) {
339                         return save_i387_fxsave( buf );
340                 } else {
341                         return save_i387_fsave( buf );
342                 }
343         } else {
344                 return save_i387_soft( &current->thread.i387.soft, buf );
345         }
346 }
347
348 static inline int restore_i387_fsave( struct _fpstate __user *buf )
349 {
350         struct task_struct *tsk = current;
351         clear_fpu( tsk );
352         return __copy_from_user( &tsk->thread.i387.fsave, buf,
353                                  sizeof(struct i387_fsave_struct) );
354 }
355
356 static int restore_i387_fxsave( struct _fpstate __user *buf )
357 {
358         int err;
359         struct task_struct *tsk = current;
360         clear_fpu( tsk );
361         err = __copy_from_user( &tsk->thread.i387.fxsave, &buf->_fxsr_env[0],
362                                 sizeof(struct i387_fxsave_struct) );
363         /* mxcsr reserved bits must be masked to zero for security reasons */
364         tsk->thread.i387.fxsave.mxcsr &= mxcsr_feature_mask;
365         return err ? 1 : convert_fxsr_from_user( &tsk->thread.i387.fxsave, buf );
366 }
367
368 int restore_i387( struct _fpstate __user *buf )
369 {
370         int err;
371
372         if ( HAVE_HWFP ) {
373                 if ( cpu_has_fxsr ) {
374                         err = restore_i387_fxsave( buf );
375                 } else {
376                         err = restore_i387_fsave( buf );
377                 }
378         } else {
379                 err = restore_i387_soft( &current->thread.i387.soft, buf );
380         }
381         set_used_math();
382         return err;
383 }
384
385 /*
386  * ptrace request handlers.
387  */
388
389 static inline int get_fpregs_fsave( struct user_i387_struct __user *buf,
390                                     struct task_struct *tsk )
391 {
392         return __copy_to_user( buf, &tsk->thread.i387.fsave,
393                                sizeof(struct user_i387_struct) );
394 }
395
396 static inline int get_fpregs_fxsave( struct user_i387_struct __user *buf,
397                                      struct task_struct *tsk )
398 {
399         return convert_fxsr_to_user( (struct _fpstate __user *)buf,
400                                      &tsk->thread.i387.fxsave );
401 }
402
403 int get_fpregs( struct user_i387_struct __user *buf, struct task_struct *tsk )
404 {
405         if ( HAVE_HWFP ) {
406                 if ( cpu_has_fxsr ) {
407                         return get_fpregs_fxsave( buf, tsk );
408                 } else {
409                         return get_fpregs_fsave( buf, tsk );
410                 }
411         } else {
412                 return save_i387_soft( &tsk->thread.i387.soft,
413                                        (struct _fpstate __user *)buf );
414         }
415 }
416
417 static inline int set_fpregs_fsave( struct task_struct *tsk,
418                                     struct user_i387_struct __user *buf )
419 {
420         return __copy_from_user( &tsk->thread.i387.fsave, buf,
421                                  sizeof(struct user_i387_struct) );
422 }
423
424 static inline int set_fpregs_fxsave( struct task_struct *tsk,
425                                      struct user_i387_struct __user *buf )
426 {
427         return convert_fxsr_from_user( &tsk->thread.i387.fxsave,
428                                        (struct _fpstate __user *)buf );
429 }
430
431 int set_fpregs( struct task_struct *tsk, struct user_i387_struct __user *buf )
432 {
433         if ( HAVE_HWFP ) {
434                 if ( cpu_has_fxsr ) {
435                         return set_fpregs_fxsave( tsk, buf );
436                 } else {
437                         return set_fpregs_fsave( tsk, buf );
438                 }
439         } else {
440                 return restore_i387_soft( &tsk->thread.i387.soft,
441                                           (struct _fpstate __user *)buf );
442         }
443 }
444
445 int get_fpxregs( struct user_fxsr_struct __user *buf, struct task_struct *tsk )
446 {
447         if ( cpu_has_fxsr ) {
448                 if (__copy_to_user( buf, &tsk->thread.i387.fxsave,
449                                     sizeof(struct user_fxsr_struct) ))
450                         return -EFAULT;
451                 return 0;
452         } else {
453                 return -EIO;
454         }
455 }
456
457 int set_fpxregs( struct task_struct *tsk, struct user_fxsr_struct __user *buf )
458 {
459         int ret = 0;
460
461         if ( cpu_has_fxsr ) {
462                 if (__copy_from_user( &tsk->thread.i387.fxsave, buf,
463                                   sizeof(struct user_fxsr_struct) ))
464                         ret = -EFAULT;
465                 /* mxcsr reserved bits must be masked to zero for security reasons */
466                 tsk->thread.i387.fxsave.mxcsr &= mxcsr_feature_mask;
467         } else {
468                 ret = -EIO;
469         }
470         return ret;
471 }
472
473 /*
474  * FPU state for core dumps.
475  */
476
477 static inline void copy_fpu_fsave( struct task_struct *tsk,
478                                    struct user_i387_struct *fpu )
479 {
480         memcpy( fpu, &tsk->thread.i387.fsave,
481                 sizeof(struct user_i387_struct) );
482 }
483
484 static inline void copy_fpu_fxsave( struct task_struct *tsk,
485                                    struct user_i387_struct *fpu )
486 {
487         unsigned short *to;
488         unsigned short *from;
489         int i;
490
491         memcpy( fpu, &tsk->thread.i387.fxsave, 7 * sizeof(long) );
492
493         to = (unsigned short *)&fpu->st_space[0];
494         from = (unsigned short *)&tsk->thread.i387.fxsave.st_space[0];
495         for ( i = 0 ; i < 8 ; i++, to += 5, from += 8 ) {
496                 memcpy( to, from, 5 * sizeof(unsigned short) );
497         }
498 }
499
500 int dump_fpu( struct pt_regs *regs, struct user_i387_struct *fpu )
501 {
502         int fpvalid;
503         struct task_struct *tsk = current;
504
505         fpvalid = !!used_math();
506         if ( fpvalid ) {
507                 unlazy_fpu( tsk );
508                 if ( cpu_has_fxsr ) {
509                         copy_fpu_fxsave( tsk, fpu );
510                 } else {
511                         copy_fpu_fsave( tsk, fpu );
512                 }
513         }
514
515         return fpvalid;
516 }
517 EXPORT_SYMBOL(dump_fpu);
518
519 int dump_task_fpu(struct task_struct *tsk, struct user_i387_struct *fpu)
520 {
521         int fpvalid = !!tsk_used_math(tsk);
522
523         if (fpvalid) {
524                 if (tsk == current)
525                         unlazy_fpu(tsk);
526                 if (cpu_has_fxsr)
527                         copy_fpu_fxsave(tsk, fpu);
528                 else
529                         copy_fpu_fsave(tsk, fpu);
530         }
531         return fpvalid;
532 }
533
534 int dump_task_extended_fpu(struct task_struct *tsk, struct user_fxsr_struct *fpu)
535 {
536         int fpvalid = tsk_used_math(tsk) && cpu_has_fxsr;
537
538         if (fpvalid) {
539                 if (tsk == current)
540                        unlazy_fpu(tsk);
541                 memcpy(fpu, &tsk->thread.i387.fxsave, sizeof(*fpu));
542         }
543         return fpvalid;
544 }