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 <registers.h> |
16 | #include <skas.h> |
17 | |
18 | #ifdef CONFIG_X86_32 |
19 | |
20 | /* |
21 | * FPU tag word conversions. |
22 | */ |
23 | |
24 | static inline unsigned short twd_i387_to_fxsr(unsigned short twd) |
25 | { |
26 | unsigned int tmp; /* to avoid 16 bit prefixes in the code */ |
27 | |
28 | /* Transform each pair of bits into 01 (valid) or 00 (empty) */ |
29 | tmp = ~twd; |
30 | tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */ |
31 | /* and move the valid bits to the lower byte. */ |
32 | tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */ |
33 | tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */ |
34 | tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */ |
35 | return tmp; |
36 | } |
37 | |
38 | static inline unsigned long twd_fxsr_to_i387(struct user_fxsr_struct *fxsave) |
39 | { |
40 | struct _fpxreg *st = NULL; |
41 | unsigned long twd = (unsigned long) fxsave->twd; |
42 | unsigned long tag; |
43 | unsigned long ret = 0xffff0000; |
44 | int i; |
45 | |
46 | #define FPREG_ADDR(f, n) ((char *)&(f)->st_space + (n) * 16) |
47 | |
48 | for (i = 0; i < 8; i++) { |
49 | if (twd & 0x1) { |
50 | st = (struct _fpxreg *) FPREG_ADDR(fxsave, i); |
51 | |
52 | switch (st->exponent & 0x7fff) { |
53 | case 0x7fff: |
54 | tag = 2; /* Special */ |
55 | break; |
56 | case 0x0000: |
57 | if ( !st->significand[0] && |
58 | !st->significand[1] && |
59 | !st->significand[2] && |
60 | !st->significand[3] ) { |
61 | tag = 1; /* Zero */ |
62 | } else { |
63 | tag = 2; /* Special */ |
64 | } |
65 | break; |
66 | default: |
67 | if (st->significand[3] & 0x8000) { |
68 | tag = 0; /* Valid */ |
69 | } else { |
70 | tag = 2; /* Special */ |
71 | } |
72 | break; |
73 | } |
74 | } else { |
75 | tag = 3; /* Empty */ |
76 | } |
77 | ret |= (tag << (2 * i)); |
78 | twd = twd >> 1; |
79 | } |
80 | return ret; |
81 | } |
82 | |
83 | static int convert_fxsr_to_user(struct _fpstate __user *buf, |
84 | struct user_fxsr_struct *fxsave) |
85 | { |
86 | unsigned long env[7]; |
87 | struct _fpreg __user *to; |
88 | struct _fpxreg *from; |
89 | int i; |
90 | |
91 | env[0] = (unsigned long)fxsave->cwd | 0xffff0000ul; |
92 | env[1] = (unsigned long)fxsave->swd | 0xffff0000ul; |
93 | env[2] = twd_fxsr_to_i387(fxsave); |
94 | env[3] = fxsave->fip; |
95 | env[4] = fxsave->fcs | ((unsigned long)fxsave->fop << 16); |
96 | env[5] = fxsave->foo; |
97 | env[6] = fxsave->fos; |
98 | |
99 | if (__copy_to_user(buf, env, 7 * sizeof(unsigned long))) |
100 | return 1; |
101 | |
102 | to = &buf->_st[0]; |
103 | from = (struct _fpxreg *) &fxsave->st_space[0]; |
104 | for (i = 0; i < 8; i++, to++, from++) { |
105 | unsigned long __user *t = (unsigned long __user *)to; |
106 | unsigned long *f = (unsigned long *)from; |
107 | |
108 | if (__put_user(*f, t) || |
109 | __put_user(*(f + 1), t + 1) || |
110 | __put_user(from->exponent, &to->exponent)) |
111 | return 1; |
112 | } |
113 | return 0; |
114 | } |
115 | |
116 | static int convert_fxsr_from_user(struct user_fxsr_struct *fxsave, |
117 | struct _fpstate __user *buf) |
118 | { |
119 | unsigned long env[7]; |
120 | struct _fpxreg *to; |
121 | struct _fpreg __user *from; |
122 | int i; |
123 | |
124 | if (copy_from_user( env, buf, 7 * sizeof(long))) |
125 | return 1; |
126 | |
127 | fxsave->cwd = (unsigned short)(env[0] & 0xffff); |
128 | fxsave->swd = (unsigned short)(env[1] & 0xffff); |
129 | fxsave->twd = twd_i387_to_fxsr((unsigned short)(env[2] & 0xffff)); |
130 | fxsave->fip = env[3]; |
131 | fxsave->fop = (unsigned short)((env[4] & 0xffff0000ul) >> 16); |
132 | fxsave->fcs = (env[4] & 0xffff); |
133 | fxsave->foo = env[5]; |
134 | fxsave->fos = env[6]; |
135 | |
136 | to = (struct _fpxreg *) &fxsave->st_space[0]; |
137 | from = &buf->_st[0]; |
138 | for (i = 0; i < 8; i++, to++, from++) { |
139 | unsigned long *t = (unsigned long *)to; |
140 | unsigned long __user *f = (unsigned long __user *)from; |
141 | |
142 | if (__get_user(*t, f) || |
143 | __get_user(*(t + 1), f + 1) || |
144 | __get_user(to->exponent, &from->exponent)) |
145 | return 1; |
146 | } |
147 | return 0; |
148 | } |
149 | |
150 | extern int have_fpx_regs; |
151 | |
152 | #endif |
153 | |
154 | static int copy_sc_from_user(struct pt_regs *regs, |
155 | struct sigcontext __user *from) |
156 | { |
157 | struct sigcontext sc; |
158 | int err, pid; |
159 | |
160 | /* Always make any pending restarted system calls return -EINTR */ |
161 | current->restart_block.fn = do_no_restart_syscall; |
162 | |
163 | err = copy_from_user(to: &sc, from, n: sizeof(sc)); |
164 | if (err) |
165 | return err; |
166 | |
167 | #define GETREG(regno, regname) regs->regs.gp[HOST_##regno] = sc.regname |
168 | |
169 | #ifdef CONFIG_X86_32 |
170 | GETREG(GS, gs); |
171 | GETREG(FS, fs); |
172 | GETREG(ES, es); |
173 | GETREG(DS, ds); |
174 | #endif |
175 | GETREG(DI, di); |
176 | GETREG(SI, si); |
177 | GETREG(BP, bp); |
178 | GETREG(SP, sp); |
179 | GETREG(BX, bx); |
180 | GETREG(DX, dx); |
181 | GETREG(CX, cx); |
182 | GETREG(AX, ax); |
183 | GETREG(IP, ip); |
184 | |
185 | #ifdef CONFIG_X86_64 |
186 | GETREG(R8, r8); |
187 | GETREG(R9, r9); |
188 | GETREG(R10, r10); |
189 | GETREG(R11, r11); |
190 | GETREG(R12, r12); |
191 | GETREG(R13, r13); |
192 | GETREG(R14, r14); |
193 | GETREG(R15, r15); |
194 | #endif |
195 | |
196 | GETREG(CS, cs); |
197 | GETREG(EFLAGS, flags); |
198 | #ifdef CONFIG_X86_32 |
199 | GETREG(SS, ss); |
200 | #endif |
201 | |
202 | #undef GETREG |
203 | |
204 | pid = userspace_pid[current_thread_info()->cpu]; |
205 | #ifdef CONFIG_X86_32 |
206 | if (have_fpx_regs) { |
207 | struct user_fxsr_struct fpx; |
208 | |
209 | err = copy_from_user(&fpx, |
210 | &((struct _fpstate __user *)sc.fpstate)->_fxsr_env[0], |
211 | sizeof(struct user_fxsr_struct)); |
212 | if (err) |
213 | return 1; |
214 | |
215 | err = convert_fxsr_from_user(&fpx, (void *)sc.fpstate); |
216 | if (err) |
217 | return 1; |
218 | |
219 | err = restore_fpx_registers(pid, (unsigned long *) &fpx); |
220 | if (err < 0) { |
221 | printk(KERN_ERR "copy_sc_from_user - " |
222 | "restore_fpx_registers failed, errno = %d\n" , |
223 | -err); |
224 | return 1; |
225 | } |
226 | } else |
227 | #endif |
228 | { |
229 | err = copy_from_user(to: regs->regs.fp, from: (void *)sc.fpstate, |
230 | n: sizeof(struct _xstate)); |
231 | if (err) |
232 | return 1; |
233 | } |
234 | return 0; |
235 | } |
236 | |
237 | static int copy_sc_to_user(struct sigcontext __user *to, |
238 | struct _xstate __user *to_fp, struct pt_regs *regs, |
239 | unsigned long mask) |
240 | { |
241 | struct sigcontext sc; |
242 | struct faultinfo * fi = ¤t->thread.arch.faultinfo; |
243 | int err, pid; |
244 | memset(&sc, 0, sizeof(struct sigcontext)); |
245 | |
246 | #define PUTREG(regno, regname) sc.regname = regs->regs.gp[HOST_##regno] |
247 | |
248 | #ifdef CONFIG_X86_32 |
249 | PUTREG(GS, gs); |
250 | PUTREG(FS, fs); |
251 | PUTREG(ES, es); |
252 | PUTREG(DS, ds); |
253 | #endif |
254 | PUTREG(DI, di); |
255 | PUTREG(SI, si); |
256 | PUTREG(BP, bp); |
257 | PUTREG(SP, sp); |
258 | PUTREG(BX, bx); |
259 | PUTREG(DX, dx); |
260 | PUTREG(CX, cx); |
261 | PUTREG(AX, ax); |
262 | #ifdef CONFIG_X86_64 |
263 | PUTREG(R8, r8); |
264 | PUTREG(R9, r9); |
265 | PUTREG(R10, r10); |
266 | PUTREG(R11, r11); |
267 | PUTREG(R12, r12); |
268 | PUTREG(R13, r13); |
269 | PUTREG(R14, r14); |
270 | PUTREG(R15, r15); |
271 | #endif |
272 | |
273 | sc.cr2 = fi->cr2; |
274 | sc.err = fi->error_code; |
275 | sc.trapno = fi->trap_no; |
276 | PUTREG(IP, ip); |
277 | PUTREG(CS, cs); |
278 | PUTREG(EFLAGS, flags); |
279 | #ifdef CONFIG_X86_32 |
280 | PUTREG(SP, sp_at_signal); |
281 | PUTREG(SS, ss); |
282 | #endif |
283 | #undef PUTREG |
284 | sc.oldmask = mask; |
285 | sc.fpstate = (unsigned long)to_fp; |
286 | |
287 | err = copy_to_user(to, from: &sc, n: sizeof(struct sigcontext)); |
288 | if (err) |
289 | return 1; |
290 | |
291 | pid = userspace_pid[current_thread_info()->cpu]; |
292 | |
293 | #ifdef CONFIG_X86_32 |
294 | if (have_fpx_regs) { |
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: to_fp, from: regs->regs.fp, n: 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 | long sys_sigreturn(void) |
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(to: &frame->info, from: &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(to: &frame->uc.uc_mcontext, to_fp: &frame->fpstate, regs, |
515 | mask: 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(to: &frame->uc.uc_sigmask, from: set, |
526 | n: 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 | long sys_rt_sigreturn(void) |
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(to: &set, from: &uc->uc_sigmask, n: sizeof(set))) |
569 | goto segfault; |
570 | |
571 | set_current_blocked(&set); |
572 | |
573 | if (copy_sc_from_user(regs: ¤t->thread.regs, from: &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 | |