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 <asm/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 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 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 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 } 114 115 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 152 153 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, 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 struct user_i387_struct fp; 229 230 err = copy_from_user(&fp, sc.fpstate, 231 sizeof(struct user_i387_struct)); 232 if (err) 233 return 1; 234 235 err = restore_fp_registers(pid, (unsigned long *) &fp); 236 if (err < 0) { 237 printk(KERN_ERR "copy_sc_from_user - " 238 "restore_fp_registers failed, errno = %d\n", 239 -err); 240 return 1; 241 } 242 } 243 return 0; 244 } 245 246 static int copy_sc_to_user(struct sigcontext __user *to, 247 struct _fpstate __user *to_fp, struct pt_regs *regs, 248 unsigned long mask) 249 { 250 struct sigcontext sc; 251 struct faultinfo * fi = ¤t->thread.arch.faultinfo; 252 int err, pid; 253 memset(&sc, 0, sizeof(struct sigcontext)); 254 255 #define PUTREG(regno, regname) sc.regname = regs->regs.gp[HOST_##regno] 256 257 #ifdef CONFIG_X86_32 258 PUTREG(GS, gs); 259 PUTREG(FS, fs); 260 PUTREG(ES, es); 261 PUTREG(DS, ds); 262 #endif 263 PUTREG(DI, di); 264 PUTREG(SI, si); 265 PUTREG(BP, bp); 266 PUTREG(SP, sp); 267 PUTREG(BX, bx); 268 PUTREG(DX, dx); 269 PUTREG(CX, cx); 270 PUTREG(AX, ax); 271 #ifdef CONFIG_X86_64 272 PUTREG(R8, r8); 273 PUTREG(R9, r9); 274 PUTREG(R10, r10); 275 PUTREG(R11, r11); 276 PUTREG(R12, r12); 277 PUTREG(R13, r13); 278 PUTREG(R14, r14); 279 PUTREG(R15, r15); 280 #endif 281 282 sc.cr2 = fi->cr2; 283 sc.err = fi->error_code; 284 sc.trapno = fi->trap_no; 285 PUTREG(IP, ip); 286 PUTREG(CS, cs); 287 PUTREG(EFLAGS, flags); 288 #ifdef CONFIG_X86_32 289 PUTREG(SP, sp_at_signal); 290 PUTREG(SS, ss); 291 #endif 292 #undef PUTREG 293 sc.oldmask = mask; 294 sc.fpstate = to_fp; 295 296 err = copy_to_user(to, &sc, sizeof(struct sigcontext)); 297 if (err) 298 return 1; 299 300 pid = userspace_pid[current_thread_info()->cpu]; 301 302 #ifdef CONFIG_X86_32 303 if (have_fpx_regs) { 304 struct user_fxsr_struct fpx; 305 306 err = save_fpx_registers(pid, (unsigned long *) &fpx); 307 if (err < 0){ 308 printk(KERN_ERR "copy_sc_to_user - save_fpx_registers " 309 "failed, errno = %d\n", err); 310 return 1; 311 } 312 313 err = convert_fxsr_to_user(to_fp, &fpx); 314 if (err) 315 return 1; 316 317 err |= __put_user(fpx.swd, &to_fp->status); 318 err |= __put_user(X86_FXSR_MAGIC, &to_fp->magic); 319 if (err) 320 return 1; 321 322 if (copy_to_user(&to_fp->_fxsr_env[0], &fpx, 323 sizeof(struct user_fxsr_struct))) 324 return 1; 325 } else 326 #endif 327 { 328 struct user_i387_struct fp; 329 330 err = save_fp_registers(pid, (unsigned long *) &fp); 331 if (copy_to_user(to_fp, &fp, sizeof(struct user_i387_struct))) 332 return 1; 333 } 334 335 return 0; 336 } 337 338 #ifdef CONFIG_X86_32 339 static int copy_ucontext_to_user(struct ucontext __user *uc, 340 struct _fpstate __user *fp, sigset_t *set, 341 unsigned long sp) 342 { 343 int err = 0; 344 345 err |= __save_altstack(&uc->uc_stack, sp); 346 err |= copy_sc_to_user(&uc->uc_mcontext, fp, ¤t->thread.regs, 0); 347 err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set)); 348 return err; 349 } 350 351 struct sigframe 352 { 353 char __user *pretcode; 354 int sig; 355 struct sigcontext sc; 356 struct _fpstate fpstate; 357 unsigned long extramask[_NSIG_WORDS-1]; 358 char retcode[8]; 359 }; 360 361 struct rt_sigframe 362 { 363 char __user *pretcode; 364 int sig; 365 struct siginfo __user *pinfo; 366 void __user *puc; 367 struct siginfo info; 368 struct ucontext uc; 369 struct _fpstate fpstate; 370 char retcode[8]; 371 }; 372 373 int setup_signal_stack_sc(unsigned long stack_top, struct ksignal *ksig, 374 struct pt_regs *regs, sigset_t *mask) 375 { 376 struct sigframe __user *frame; 377 void __user *restorer; 378 int err = 0, sig = ksig->sig; 379 380 /* This is the same calculation as i386 - ((sp + 4) & 15) == 0 */ 381 stack_top = ((stack_top + 4) & -16UL) - 4; 382 frame = (struct sigframe __user *) stack_top - 1; 383 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 384 return 1; 385 386 restorer = frame->retcode; 387 if (ksig->ka.sa.sa_flags & SA_RESTORER) 388 restorer = ksig->ka.sa.sa_restorer; 389 390 err |= __put_user(restorer, &frame->pretcode); 391 err |= __put_user(sig, &frame->sig); 392 err |= copy_sc_to_user(&frame->sc, &frame->fpstate, regs, mask->sig[0]); 393 if (_NSIG_WORDS > 1) 394 err |= __copy_to_user(&frame->extramask, &mask->sig[1], 395 sizeof(frame->extramask)); 396 397 /* 398 * This is popl %eax ; movl $,%eax ; int $0x80 399 * 400 * WE DO NOT USE IT ANY MORE! It's only left here for historical 401 * reasons and because gdb uses it as a signature to notice 402 * signal handler stack frames. 403 */ 404 err |= __put_user(0xb858, (short __user *)(frame->retcode+0)); 405 err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2)); 406 err |= __put_user(0x80cd, (short __user *)(frame->retcode+6)); 407 408 if (err) 409 return err; 410 411 PT_REGS_SP(regs) = (unsigned long) frame; 412 PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler; 413 PT_REGS_AX(regs) = (unsigned long) sig; 414 PT_REGS_DX(regs) = (unsigned long) 0; 415 PT_REGS_CX(regs) = (unsigned long) 0; 416 return 0; 417 } 418 419 int setup_signal_stack_si(unsigned long stack_top, struct ksignal *ksig, 420 struct pt_regs *regs, sigset_t *mask) 421 { 422 struct rt_sigframe __user *frame; 423 void __user *restorer; 424 int err = 0, sig = ksig->sig; 425 426 stack_top &= -8UL; 427 frame = (struct rt_sigframe __user *) stack_top - 1; 428 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 429 return 1; 430 431 restorer = frame->retcode; 432 if (ksig->ka.sa.sa_flags & SA_RESTORER) 433 restorer = ksig->ka.sa.sa_restorer; 434 435 err |= __put_user(restorer, &frame->pretcode); 436 err |= __put_user(sig, &frame->sig); 437 err |= __put_user(&frame->info, &frame->pinfo); 438 err |= __put_user(&frame->uc, &frame->puc); 439 err |= copy_siginfo_to_user(&frame->info, &ksig->info); 440 err |= copy_ucontext_to_user(&frame->uc, &frame->fpstate, mask, 441 PT_REGS_SP(regs)); 442 443 /* 444 * This is movl $,%eax ; int $0x80 445 * 446 * WE DO NOT USE IT ANY MORE! It's only left here for historical 447 * reasons and because gdb uses it as a signature to notice 448 * signal handler stack frames. 449 */ 450 err |= __put_user(0xb8, (char __user *)(frame->retcode+0)); 451 err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1)); 452 err |= __put_user(0x80cd, (short __user *)(frame->retcode+5)); 453 454 if (err) 455 return err; 456 457 PT_REGS_SP(regs) = (unsigned long) frame; 458 PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler; 459 PT_REGS_AX(regs) = (unsigned long) sig; 460 PT_REGS_DX(regs) = (unsigned long) &frame->info; 461 PT_REGS_CX(regs) = (unsigned long) &frame->uc; 462 return 0; 463 } 464 465 long sys_sigreturn(void) 466 { 467 unsigned long sp = PT_REGS_SP(¤t->thread.regs); 468 struct sigframe __user *frame = (struct sigframe __user *)(sp - 8); 469 sigset_t set; 470 struct sigcontext __user *sc = &frame->sc; 471 unsigned long __user *oldmask = &sc->oldmask; 472 unsigned long __user *extramask = frame->extramask; 473 int sig_size = (_NSIG_WORDS - 1) * sizeof(unsigned long); 474 475 if (copy_from_user(&set.sig[0], oldmask, sizeof(set.sig[0])) || 476 copy_from_user(&set.sig[1], extramask, sig_size)) 477 goto segfault; 478 479 set_current_blocked(&set); 480 481 if (copy_sc_from_user(¤t->thread.regs, sc)) 482 goto segfault; 483 484 /* Avoid ERESTART handling */ 485 PT_REGS_SYSCALL_NR(¤t->thread.regs) = -1; 486 return PT_REGS_SYSCALL_RET(¤t->thread.regs); 487 488 segfault: 489 force_sig(SIGSEGV, current); 490 return 0; 491 } 492 493 #else 494 495 struct rt_sigframe 496 { 497 char __user *pretcode; 498 struct ucontext uc; 499 struct siginfo info; 500 struct _fpstate fpstate; 501 }; 502 503 int setup_signal_stack_si(unsigned long stack_top, struct ksignal *ksig, 504 struct pt_regs *regs, sigset_t *set) 505 { 506 struct rt_sigframe __user *frame; 507 int err = 0, sig = ksig->sig; 508 509 frame = (struct rt_sigframe __user *) 510 round_down(stack_top - sizeof(struct rt_sigframe), 16); 511 /* Subtract 128 for a red zone and 8 for proper alignment */ 512 frame = (struct rt_sigframe __user *) ((unsigned long) frame - 128 - 8); 513 514 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 515 goto out; 516 517 if (ksig->ka.sa.sa_flags & SA_SIGINFO) { 518 err |= copy_siginfo_to_user(&frame->info, &ksig->info); 519 if (err) 520 goto out; 521 } 522 523 /* Create the ucontext. */ 524 err |= __put_user(0, &frame->uc.uc_flags); 525 err |= __put_user(0, &frame->uc.uc_link); 526 err |= __save_altstack(&frame->uc.uc_stack, PT_REGS_SP(regs)); 527 err |= copy_sc_to_user(&frame->uc.uc_mcontext, &frame->fpstate, regs, 528 set->sig[0]); 529 err |= __put_user(&frame->fpstate, &frame->uc.uc_mcontext.fpstate); 530 if (sizeof(*set) == 16) { 531 err |= __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]); 532 err |= __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]); 533 } 534 else 535 err |= __copy_to_user(&frame->uc.uc_sigmask, set, 536 sizeof(*set)); 537 538 /* 539 * Set up to return from userspace. If provided, use a stub 540 * already in userspace. 541 */ 542 /* x86-64 should always use SA_RESTORER. */ 543 if (ksig->ka.sa.sa_flags & SA_RESTORER) 544 err |= __put_user((void *)ksig->ka.sa.sa_restorer, 545 &frame->pretcode); 546 else 547 /* could use a vstub here */ 548 return err; 549 550 if (err) 551 return err; 552 553 PT_REGS_SP(regs) = (unsigned long) frame; 554 PT_REGS_DI(regs) = sig; 555 /* In case the signal handler was declared without prototypes */ 556 PT_REGS_AX(regs) = 0; 557 558 /* 559 * This also works for non SA_SIGINFO handlers because they expect the 560 * next argument after the signal number on the stack. 561 */ 562 PT_REGS_SI(regs) = (unsigned long) &frame->info; 563 PT_REGS_DX(regs) = (unsigned long) &frame->uc; 564 PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler; 565 out: 566 return err; 567 } 568 #endif 569 570 long sys_rt_sigreturn(void) 571 { 572 unsigned long sp = PT_REGS_SP(¤t->thread.regs); 573 struct rt_sigframe __user *frame = 574 (struct rt_sigframe __user *)(sp - sizeof(long)); 575 struct ucontext __user *uc = &frame->uc; 576 sigset_t set; 577 578 if (copy_from_user(&set, &uc->uc_sigmask, sizeof(set))) 579 goto segfault; 580 581 set_current_blocked(&set); 582 583 if (copy_sc_from_user(¤t->thread.regs, &uc->uc_mcontext)) 584 goto segfault; 585 586 /* Avoid ERESTART handling */ 587 PT_REGS_SYSCALL_NR(¤t->thread.regs) = -1; 588 return PT_REGS_SYSCALL_RET(¤t->thread.regs); 589 590 segfault: 591 force_sig(SIGSEGV, current); 592 return 0; 593 } 594