1 /*
2 * Copyright (C) 2003 PathScale, Inc.
3 * Copyright (C) 2003 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 * Licensed under the GPL
5 */
6
7
8 #include <linux/personality.h>
9 #include <linux/ptrace.h>
10 #include <linux/kernel.h>
11 #include <linux/syscalls.h>
12 #include <asm/unistd.h>
13 #include <linux/uaccess.h>
14 #include <asm/ucontext.h>
15 #include <frame_kern.h>
16 #include <registers.h>
17 #include <skas.h>
18
19 #ifdef CONFIG_X86_32
20
21 /*
22 * FPU tag word conversions.
23 */
24
25 static inline unsigned short twd_i387_to_fxsr(unsigned short twd)
26 {
27 unsigned int tmp; /* to avoid 16 bit prefixes in the code */
28
29 /* Transform each pair of bits into 01 (valid) or 00 (empty) */
30 tmp = ~twd;
31 tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */
32 /* and move the valid bits to the lower byte. */
33 tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */
34 tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */
35 tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */
36 return tmp;
37 }
38
39 static inline unsigned long twd_fxsr_to_i387(struct user_fxsr_struct *fxsave)
40 {
41 struct _fpxreg *st = NULL;
42 unsigned long twd = (unsigned long) fxsave->twd;
43 unsigned long tag;
44 unsigned long ret = 0xffff0000;
45 int i;
46
47 #define FPREG_ADDR(f, n) ((char *)&(f)->st_space + (n) * 16)
48
49 for (i = 0; i < 8; i++) {
50 if (twd & 0x1) {
51 st = (struct _fpxreg *) FPREG_ADDR(fxsave, i);
52
53 switch (st->exponent & 0x7fff) {
54 case 0x7fff:
55 tag = 2; /* Special */
56 break;
57 case 0x0000:
58 if ( !st->significand[0] &&
59 !st->significand[1] &&
60 !st->significand[2] &&
61 !st->significand[3] ) {
62 tag = 1; /* Zero */
63 } else {
64 tag = 2; /* Special */
65 }
66 break;
67 default:
68 if (st->significand[3] & 0x8000) {
69 tag = 0; /* Valid */
70 } else {
71 tag = 2; /* Special */
72 }
73 break;
74 }
75 } else {
76 tag = 3; /* Empty */
77 }
78 ret |= (tag << (2 * i));
79 twd = twd >> 1;
80 }
81 return ret;
82 }
83
84 static int convert_fxsr_to_user(struct _fpstate __user *buf,
85 struct user_fxsr_struct *fxsave)
86 {
87 unsigned long env[7];
88 struct _fpreg __user *to;
89 struct _fpxreg *from;
90 int i;
91
92 env[0] = (unsigned long)fxsave->cwd | 0xffff0000ul;
93 env[1] = (unsigned long)fxsave->swd | 0xffff0000ul;
94 env[2] = twd_fxsr_to_i387(fxsave);
95 env[3] = fxsave->fip;
96 env[4] = fxsave->fcs | ((unsigned long)fxsave->fop << 16);
97 env[5] = fxsave->foo;
98 env[6] = fxsave->fos;
99
100 if (__copy_to_user(buf, env, 7 * sizeof(unsigned long)))
101 return 1;
102
103 to = &buf->_st[0];
104 from = (struct _fpxreg *) &fxsave->st_space[0];
105 for (i = 0; i < 8; i++, to++, from++) {
106 unsigned long __user *t = (unsigned long __user *)to;
107 unsigned long *f = (unsigned long *)from;
108
109 if (__put_user(*f, t) ||
110 __put_user(*(f + 1), t + 1) ||
111 __put_user(from->exponent, &to->exponent))
112 return 1;
113 }
114 return 0;
115 }
116
117 static int convert_fxsr_from_user(struct user_fxsr_struct *fxsave,
118 struct _fpstate __user *buf)
119 {
120 unsigned long env[7];
121 struct _fpxreg *to;
122 struct _fpreg __user *from;
123 int i;
124
125 if (copy_from_user( env, buf, 7 * sizeof(long)))
126 return 1;
127
128 fxsave->cwd = (unsigned short)(env[0] & 0xffff);
129 fxsave->swd = (unsigned short)(env[1] & 0xffff);
130 fxsave->twd = twd_i387_to_fxsr((unsigned short)(env[2] & 0xffff));
131 fxsave->fip = env[3];
132 fxsave->fop = (unsigned short)((env[4] & 0xffff0000ul) >> 16);
133 fxsave->fcs = (env[4] & 0xffff);
134 fxsave->foo = env[5];
135 fxsave->fos = env[6];
136
137 to = (struct _fpxreg *) &fxsave->st_space[0];
138 from = &buf->_st[0];
139 for (i = 0; i < 8; i++, to++, from++) {
140 unsigned long *t = (unsigned long *)to;
141 unsigned long __user *f = (unsigned long __user *)from;
142
143 if (__get_user(*t, f) ||
144 __get_user(*(t + 1), f + 1) ||
145 __get_user(to->exponent, &from->exponent))
146 return 1;
147 }
148 return 0;
149 }
150
151 extern int have_fpx_regs;
152
153 #endif
154
155 static int copy_sc_from_user(struct pt_regs *regs,
156 struct sigcontext __user *from)
157 {
158 struct sigcontext sc;
159 int err;
160
161 /* Always make any pending restarted system calls return -EINTR */
162 current->restart_block.fn = do_no_restart_syscall;
163
164 err = copy_from_user(&sc, from, sizeof(sc));
165 if (err)
166 return err;
167
168 #define GETREG(regno, regname) regs->regs.gp[HOST_##regno] = sc.regname
169
170 #ifdef CONFIG_X86_32
171 GETREG(GS, gs);
172 GETREG(FS, fs);
173 GETREG(ES, es);
174 GETREG(DS, ds);
175 #endif
176 GETREG(DI, di);
177 GETREG(SI, si);
178 GETREG(BP, bp);
179 GETREG(SP, sp);
180 GETREG(BX, bx);
181 GETREG(DX, dx);
182 GETREG(CX, cx);
183 GETREG(AX, ax);
184 GETREG(IP, ip);
185
186 #ifdef CONFIG_X86_64
187 GETREG(R8, r8);
188 GETREG(R9, r9);
189 GETREG(R10, r10);
190 GETREG(R11, r11);
191 GETREG(R12, r12);
192 GETREG(R13, r13);
193 GETREG(R14, r14);
194 GETREG(R15, r15);
195 #endif
196
197 GETREG(CS, cs);
198 GETREG(EFLAGS, flags);
199 #ifdef CONFIG_X86_32
200 GETREG(SS, ss);
201 #endif
202
203 #undef GETREG
204
205 #ifdef CONFIG_X86_32
206 if (have_fpx_regs) {
207 struct user_fxsr_struct fpx;
208 int pid = userspace_pid[current_thread_info()->cpu];
209
210 err = copy_from_user(&fpx,
211 &((struct _fpstate __user *)sc.fpstate)->_fxsr_env[0],
212 sizeof(struct user_fxsr_struct));
213 if (err)
214 return 1;
215
216 err = convert_fxsr_from_user(&fpx, (void *)sc.fpstate);
217 if (err)
218 return 1;
219
220 err = restore_fpx_registers(pid, (unsigned long *) &fpx);
221 if (err < 0) {
222 printk(KERN_ERR "copy_sc_from_user - "
223 "restore_fpx_registers failed, errno = %d\n",
224 -err);
225 return 1;
226 }
227 } else
228 #endif
229 {
230 err = copy_from_user(regs->regs.fp, (void *)sc.fpstate,
231 sizeof(struct _xstate));
232 if (err)
233 return 1;
234 }
235 return 0;
236 }
237
238 static int copy_sc_to_user(struct sigcontext __user *to,
239 struct _xstate __user *to_fp, struct pt_regs *regs,
240 unsigned long mask)
241 {
242 struct sigcontext sc;
243 struct faultinfo * fi = ¤t->thread.arch.faultinfo;
244 int err;
245 memset(&sc, 0, sizeof(struct sigcontext));
246
247 #define PUTREG(regno, regname) sc.regname = regs->regs.gp[HOST_##regno]
248
249 #ifdef CONFIG_X86_32
250 PUTREG(GS, gs);
251 PUTREG(FS, fs);
252 PUTREG(ES, es);
253 PUTREG(DS, ds);
254 #endif
255 PUTREG(DI, di);
256 PUTREG(SI, si);
257 PUTREG(BP, bp);
258 PUTREG(SP, sp);
259 PUTREG(BX, bx);
260 PUTREG(DX, dx);
261 PUTREG(CX, cx);
262 PUTREG(AX, ax);
263 #ifdef CONFIG_X86_64
264 PUTREG(R8, r8);
265 PUTREG(R9, r9);
266 PUTREG(R10, r10);
267 PUTREG(R11, r11);
268 PUTREG(R12, r12);
269 PUTREG(R13, r13);
270 PUTREG(R14, r14);
271 PUTREG(R15, r15);
272 #endif
273
274 sc.cr2 = fi->cr2;
275 sc.err = fi->error_code;
276 sc.trapno = fi->trap_no;
277 PUTREG(IP, ip);
278 PUTREG(CS, cs);
279 PUTREG(EFLAGS, flags);
280 #ifdef CONFIG_X86_32
281 PUTREG(SP, sp_at_signal);
282 PUTREG(SS, ss);
283 #endif
284 #undef PUTREG
285 sc.oldmask = mask;
286 sc.fpstate = (unsigned long)to_fp;
287
288 err = copy_to_user(to, &sc, sizeof(struct sigcontext));
289 if (err)
290 return 1;
291
292 #ifdef CONFIG_X86_32
293 if (have_fpx_regs) {
294 int pid = userspace_pid[current_thread_info()->cpu];
295 struct user_fxsr_struct fpx;
296
297 err = save_fpx_registers(pid, (unsigned long *) &fpx);
298 if (err < 0){
299 printk(KERN_ERR "copy_sc_to_user - save_fpx_registers "
300 "failed, errno = %d\n", err);
301 return 1;
302 }
303
304 err = convert_fxsr_to_user(&to_fp->fpstate, &fpx);
305 if (err)
306 return 1;
307
308 err |= __put_user(fpx.swd, &to_fp->fpstate.status);
309 err |= __put_user(X86_FXSR_MAGIC, &to_fp->fpstate.magic);
310 if (err)
311 return 1;
312
313 if (copy_to_user(&to_fp->fpstate._fxsr_env[0], &fpx,
314 sizeof(struct user_fxsr_struct)))
315 return 1;
316 } else
317 #endif
318 {
319 if (copy_to_user(to_fp, regs->regs.fp, sizeof(struct _xstate)))
320 return 1;
321 }
322
323 return 0;
324 }
325
326 #ifdef CONFIG_X86_32
327 static int copy_ucontext_to_user(struct ucontext __user *uc,
328 struct _xstate __user *fp, sigset_t *set,
329 unsigned long sp)
330 {
331 int err = 0;
332
333 err |= __save_altstack(&uc->uc_stack, sp);
334 err |= copy_sc_to_user(&uc->uc_mcontext, fp, ¤t->thread.regs, 0);
335 err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set));
336 return err;
337 }
338
339 struct sigframe
340 {
341 char __user *pretcode;
342 int sig;
343 struct sigcontext sc;
344 struct _xstate fpstate;
345 unsigned long extramask[_NSIG_WORDS-1];
346 char retcode[8];
347 };
348
349 struct rt_sigframe
350 {
351 char __user *pretcode;
352 int sig;
353 struct siginfo __user *pinfo;
354 void __user *puc;
355 struct siginfo info;
356 struct ucontext uc;
357 struct _xstate fpstate;
358 char retcode[8];
359 };
360
361 int setup_signal_stack_sc(unsigned long stack_top, struct ksignal *ksig,
362 struct pt_regs *regs, sigset_t *mask)
363 {
364 struct sigframe __user *frame;
365 void __user *restorer;
366 int err = 0, sig = ksig->sig;
367
368 /* This is the same calculation as i386 - ((sp + 4) & 15) == 0 */
369 stack_top = ((stack_top + 4) & -16UL) - 4;
370 frame = (struct sigframe __user *) stack_top - 1;
371 if (!access_ok(frame, sizeof(*frame)))
372 return 1;
373
374 restorer = frame->retcode;
375 if (ksig->ka.sa.sa_flags & SA_RESTORER)
376 restorer = ksig->ka.sa.sa_restorer;
377
378 err |= __put_user(restorer, &frame->pretcode);
379 err |= __put_user(sig, &frame->sig);
380 err |= copy_sc_to_user(&frame->sc, &frame->fpstate, regs, mask->sig[0]);
381 if (_NSIG_WORDS > 1)
382 err |= __copy_to_user(&frame->extramask, &mask->sig[1],
383 sizeof(frame->extramask));
384
385 /*
386 * This is popl %eax ; movl $,%eax ; int $0x80
387 *
388 * WE DO NOT USE IT ANY MORE! It's only left here for historical
389 * reasons and because gdb uses it as a signature to notice
390 * signal handler stack frames.
391 */
392 err |= __put_user(0xb858, (short __user *)(frame->retcode+0));
393 err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
394 err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));
395
396 if (err)
397 return err;
398
399 PT_REGS_SP(regs) = (unsigned long) frame;
400 PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler;
401 PT_REGS_AX(regs) = (unsigned long) sig;
402 PT_REGS_DX(regs) = (unsigned long) 0;
403 PT_REGS_CX(regs) = (unsigned long) 0;
404 return 0;
405 }
406
407 int setup_signal_stack_si(unsigned long stack_top, struct ksignal *ksig,
408 struct pt_regs *regs, sigset_t *mask)
409 {
410 struct rt_sigframe __user *frame;
411 void __user *restorer;
412 int err = 0, sig = ksig->sig;
413
414 stack_top &= -8UL;
415 frame = (struct rt_sigframe __user *) stack_top - 1;
416 if (!access_ok(frame, sizeof(*frame)))
417 return 1;
418
419 restorer = frame->retcode;
420 if (ksig->ka.sa.sa_flags & SA_RESTORER)
421 restorer = ksig->ka.sa.sa_restorer;
422
423 err |= __put_user(restorer, &frame->pretcode);
424 err |= __put_user(sig, &frame->sig);
425 err |= __put_user(&frame->info, &frame->pinfo);
426 err |= __put_user(&frame->uc, &frame->puc);
427 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
428 err |= copy_ucontext_to_user(&frame->uc, &frame->fpstate, mask,
429 PT_REGS_SP(regs));
430
431 /*
432 * This is movl $,%eax ; int $0x80
433 *
434 * WE DO NOT USE IT ANY MORE! It's only left here for historical
435 * reasons and because gdb uses it as a signature to notice
436 * signal handler stack frames.
437 */
438 err |= __put_user(0xb8, (char __user *)(frame->retcode+0));
439 err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
440 err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));
441
442 if (err)
443 return err;
444
445 PT_REGS_SP(regs) = (unsigned long) frame;
446 PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler;
447 PT_REGS_AX(regs) = (unsigned long) sig;
448 PT_REGS_DX(regs) = (unsigned long) &frame->info;
449 PT_REGS_CX(regs) = (unsigned long) &frame->uc;
450 return 0;
451 }
452
453 SYSCALL_DEFINE0(sigreturn)
454 {
455 unsigned long sp = PT_REGS_SP(¤t->thread.regs);
456 struct sigframe __user *frame = (struct sigframe __user *)(sp - 8);
457 sigset_t set;
458 struct sigcontext __user *sc = &frame->sc;
459 int sig_size = (_NSIG_WORDS - 1) * sizeof(unsigned long);
460
461 if (copy_from_user(&set.sig[0], &sc->oldmask, sizeof(set.sig[0])) ||
462 copy_from_user(&set.sig[1], frame->extramask, sig_size))
463 goto segfault;
464
465 set_current_blocked(&set);
466
467 if (copy_sc_from_user(¤t->thread.regs, sc))
468 goto segfault;
469
470 /* Avoid ERESTART handling */
471 PT_REGS_SYSCALL_NR(¤t->thread.regs) = -1;
472 return PT_REGS_SYSCALL_RET(¤t->thread.regs);
473
474 segfault:
475 force_sig(SIGSEGV);
476 return 0;
477 }
478
479 #else
480
481 struct rt_sigframe
482 {
483 char __user *pretcode;
484 struct ucontext uc;
485 struct siginfo info;
486 struct _xstate fpstate;
487 };
488
489 int setup_signal_stack_si(unsigned long stack_top, struct ksignal *ksig,
490 struct pt_regs *regs, sigset_t *set)
491 {
492 struct rt_sigframe __user *frame;
493 int err = 0, sig = ksig->sig;
494 unsigned long fp_to;
495
496 frame = (struct rt_sigframe __user *)
497 round_down(stack_top - sizeof(struct rt_sigframe), 16);
498 /* Subtract 128 for a red zone and 8 for proper alignment */
499 frame = (struct rt_sigframe __user *) ((unsigned long) frame - 128 - 8);
500
501 if (!access_ok(frame, sizeof(*frame)))
502 goto out;
503
504 if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
505 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
506 if (err)
507 goto out;
508 }
509
510 /* Create the ucontext. */
511 err |= __put_user(0, &frame->uc.uc_flags);
512 err |= __put_user(0, &frame->uc.uc_link);
513 err |= __save_altstack(&frame->uc.uc_stack, PT_REGS_SP(regs));
514 err |= copy_sc_to_user(&frame->uc.uc_mcontext, &frame->fpstate, regs,
515 set->sig[0]);
516
517 fp_to = (unsigned long)&frame->fpstate;
518
519 err |= __put_user(fp_to, &frame->uc.uc_mcontext.fpstate);
520 if (sizeof(*set) == 16) {
521 err |= __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
522 err |= __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
523 }
524 else
525 err |= __copy_to_user(&frame->uc.uc_sigmask, set,
526 sizeof(*set));
527
528 /*
529 * Set up to return from userspace. If provided, use a stub
530 * already in userspace.
531 */
532 /* x86-64 should always use SA_RESTORER. */
533 if (ksig->ka.sa.sa_flags & SA_RESTORER)
534 err |= __put_user((void *)ksig->ka.sa.sa_restorer,
535 &frame->pretcode);
536 else
537 /* could use a vstub here */
538 return err;
539
540 if (err)
541 return err;
542
543 PT_REGS_SP(regs) = (unsigned long) frame;
544 PT_REGS_DI(regs) = sig;
545 /* In case the signal handler was declared without prototypes */
546 PT_REGS_AX(regs) = 0;
547
548 /*
549 * This also works for non SA_SIGINFO handlers because they expect the
550 * next argument after the signal number on the stack.
551 */
552 PT_REGS_SI(regs) = (unsigned long) &frame->info;
553 PT_REGS_DX(regs) = (unsigned long) &frame->uc;
554 PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler;
555 out:
556 return err;
557 }
558 #endif
559
560 SYSCALL_DEFINE0(rt_sigreturn)
561 {
562 unsigned long sp = PT_REGS_SP(¤t->thread.regs);
563 struct rt_sigframe __user *frame =
564 (struct rt_sigframe __user *)(sp - sizeof(long));
565 struct ucontext __user *uc = &frame->uc;
566 sigset_t set;
567
568 if (copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
569 goto segfault;
570
571 set_current_blocked(&set);
572
573 if (copy_sc_from_user(¤t->thread.regs, &uc->uc_mcontext))
574 goto segfault;
575
576 /* Avoid ERESTART handling */
577 PT_REGS_SYSCALL_NR(¤t->thread.regs) = -1;
578 return PT_REGS_SYSCALL_RET(¤t->thread.regs);
579
580 segfault:
581 force_sig(SIGSEGV);
582 return 0;
583 }
584
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