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