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 err = copy_from_user(&sc, from, sizeof(sc)); 160 if (err) 161 return err; 162 163 #define GETREG(regno, regname) regs->regs.gp[HOST_##regno] = sc.regname 164 165 #ifdef CONFIG_X86_32 166 GETREG(GS, gs); 167 GETREG(FS, fs); 168 GETREG(ES, es); 169 GETREG(DS, ds); 170 #endif 171 GETREG(DI, di); 172 GETREG(SI, si); 173 GETREG(BP, bp); 174 GETREG(SP, sp); 175 GETREG(BX, bx); 176 GETREG(DX, dx); 177 GETREG(CX, cx); 178 GETREG(AX, ax); 179 GETREG(IP, ip); 180 181 #ifdef CONFIG_X86_64 182 GETREG(R8, r8); 183 GETREG(R9, r9); 184 GETREG(R10, r10); 185 GETREG(R11, r11); 186 GETREG(R12, r12); 187 GETREG(R13, r13); 188 GETREG(R14, r14); 189 GETREG(R15, r15); 190 #endif 191 192 GETREG(CS, cs); 193 GETREG(EFLAGS, flags); 194 #ifdef CONFIG_X86_32 195 GETREG(SS, ss); 196 #endif 197 198 #undef GETREG 199 200 pid = userspace_pid[current_thread_info()->cpu]; 201 #ifdef CONFIG_X86_32 202 if (have_fpx_regs) { 203 struct user_fxsr_struct fpx; 204 205 err = copy_from_user(&fpx, 206 &((struct _fpstate __user *)sc.fpstate)->_fxsr_env[0], 207 sizeof(struct user_fxsr_struct)); 208 if (err) 209 return 1; 210 211 err = convert_fxsr_from_user(&fpx, sc.fpstate); 212 if (err) 213 return 1; 214 215 err = restore_fpx_registers(pid, (unsigned long *) &fpx); 216 if (err < 0) { 217 printk(KERN_ERR "copy_sc_from_user - " 218 "restore_fpx_registers failed, errno = %d\n", 219 -err); 220 return 1; 221 } 222 } else 223 #endif 224 { 225 struct user_i387_struct fp; 226 227 err = copy_from_user(&fp, sc.fpstate, 228 sizeof(struct user_i387_struct)); 229 if (err) 230 return 1; 231 232 err = restore_fp_registers(pid, (unsigned long *) &fp); 233 if (err < 0) { 234 printk(KERN_ERR "copy_sc_from_user - " 235 "restore_fp_registers failed, errno = %d\n", 236 -err); 237 return 1; 238 } 239 } 240 return 0; 241 } 242 243 static int copy_sc_to_user(struct sigcontext __user *to, 244 struct _fpstate __user *to_fp, struct pt_regs *regs, 245 unsigned long mask) 246 { 247 struct sigcontext sc; 248 struct faultinfo * fi = ¤t->thread.arch.faultinfo; 249 int err, pid; 250 memset(&sc, 0, sizeof(struct sigcontext)); 251 252 #define PUTREG(regno, regname) sc.regname = regs->regs.gp[HOST_##regno] 253 254 #ifdef CONFIG_X86_32 255 PUTREG(GS, gs); 256 PUTREG(FS, fs); 257 PUTREG(ES, es); 258 PUTREG(DS, ds); 259 #endif 260 PUTREG(DI, di); 261 PUTREG(SI, si); 262 PUTREG(BP, bp); 263 PUTREG(SP, sp); 264 PUTREG(BX, bx); 265 PUTREG(DX, dx); 266 PUTREG(CX, cx); 267 PUTREG(AX, ax); 268 #ifdef CONFIG_X86_64 269 PUTREG(R8, r8); 270 PUTREG(R9, r9); 271 PUTREG(R10, r10); 272 PUTREG(R11, r11); 273 PUTREG(R12, r12); 274 PUTREG(R13, r13); 275 PUTREG(R14, r14); 276 PUTREG(R15, r15); 277 #endif 278 279 sc.cr2 = fi->cr2; 280 sc.err = fi->error_code; 281 sc.trapno = fi->trap_no; 282 PUTREG(IP, ip); 283 PUTREG(CS, cs); 284 PUTREG(EFLAGS, flags); 285 #ifdef CONFIG_X86_32 286 PUTREG(SP, sp_at_signal); 287 PUTREG(SS, ss); 288 #endif 289 #undef PUTREG 290 sc.oldmask = mask; 291 sc.fpstate = to_fp; 292 293 err = copy_to_user(to, &sc, sizeof(struct sigcontext)); 294 if (err) 295 return 1; 296 297 pid = userspace_pid[current_thread_info()->cpu]; 298 299 #ifdef CONFIG_X86_32 300 if (have_fpx_regs) { 301 struct user_fxsr_struct fpx; 302 303 err = save_fpx_registers(pid, (unsigned long *) &fpx); 304 if (err < 0){ 305 printk(KERN_ERR "copy_sc_to_user - save_fpx_registers " 306 "failed, errno = %d\n", err); 307 return 1; 308 } 309 310 err = convert_fxsr_to_user(to_fp, &fpx); 311 if (err) 312 return 1; 313 314 err |= __put_user(fpx.swd, &to_fp->status); 315 err |= __put_user(X86_FXSR_MAGIC, &to_fp->magic); 316 if (err) 317 return 1; 318 319 if (copy_to_user(&to_fp->_fxsr_env[0], &fpx, 320 sizeof(struct user_fxsr_struct))) 321 return 1; 322 } else 323 #endif 324 { 325 struct user_i387_struct fp; 326 327 err = save_fp_registers(pid, (unsigned long *) &fp); 328 if (copy_to_user(to_fp, &fp, sizeof(struct user_i387_struct))) 329 return 1; 330 } 331 332 return 0; 333 } 334 335 #ifdef CONFIG_X86_32 336 static int copy_ucontext_to_user(struct ucontext __user *uc, 337 struct _fpstate __user *fp, sigset_t *set, 338 unsigned long sp) 339 { 340 int err = 0; 341 342 err |= put_user(current->sas_ss_sp, &uc->uc_stack.ss_sp); 343 err |= put_user(sas_ss_flags(sp), &uc->uc_stack.ss_flags); 344 err |= put_user(current->sas_ss_size, &uc->uc_stack.ss_size); 345 err |= copy_sc_to_user(&uc->uc_mcontext, fp, ¤t->thread.regs, 0); 346 err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set)); 347 return err; 348 } 349 350 struct sigframe 351 { 352 char __user *pretcode; 353 int sig; 354 struct sigcontext sc; 355 struct _fpstate fpstate; 356 unsigned long extramask[_NSIG_WORDS-1]; 357 char retcode[8]; 358 }; 359 360 struct rt_sigframe 361 { 362 char __user *pretcode; 363 int sig; 364 struct siginfo __user *pinfo; 365 void __user *puc; 366 struct siginfo info; 367 struct ucontext uc; 368 struct _fpstate fpstate; 369 char retcode[8]; 370 }; 371 372 int setup_signal_stack_sc(unsigned long stack_top, int sig, 373 struct k_sigaction *ka, struct pt_regs *regs, 374 sigset_t *mask) 375 { 376 struct sigframe __user *frame; 377 void __user *restorer; 378 int err = 0; 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 (ka->sa.sa_flags & SA_RESTORER) 388 restorer = 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) ka->sa.sa_handler; 413 PT_REGS_EAX(regs) = (unsigned long) sig; 414 PT_REGS_EDX(regs) = (unsigned long) 0; 415 PT_REGS_ECX(regs) = (unsigned long) 0; 416 417 if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED)) 418 ptrace_notify(SIGTRAP); 419 return 0; 420 } 421 422 int setup_signal_stack_si(unsigned long stack_top, int sig, 423 struct k_sigaction *ka, struct pt_regs *regs, 424 siginfo_t *info, sigset_t *mask) 425 { 426 struct rt_sigframe __user *frame; 427 void __user *restorer; 428 int err = 0; 429 430 stack_top &= -8UL; 431 frame = (struct rt_sigframe __user *) stack_top - 1; 432 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 433 return 1; 434 435 restorer = frame->retcode; 436 if (ka->sa.sa_flags & SA_RESTORER) 437 restorer = ka->sa.sa_restorer; 438 439 err |= __put_user(restorer, &frame->pretcode); 440 err |= __put_user(sig, &frame->sig); 441 err |= __put_user(&frame->info, &frame->pinfo); 442 err |= __put_user(&frame->uc, &frame->puc); 443 err |= copy_siginfo_to_user(&frame->info, info); 444 err |= copy_ucontext_to_user(&frame->uc, &frame->fpstate, mask, 445 PT_REGS_SP(regs)); 446 447 /* 448 * This is movl $,%eax ; int $0x80 449 * 450 * WE DO NOT USE IT ANY MORE! It's only left here for historical 451 * reasons and because gdb uses it as a signature to notice 452 * signal handler stack frames. 453 */ 454 err |= __put_user(0xb8, (char __user *)(frame->retcode+0)); 455 err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1)); 456 err |= __put_user(0x80cd, (short __user *)(frame->retcode+5)); 457 458 if (err) 459 return err; 460 461 PT_REGS_SP(regs) = (unsigned long) frame; 462 PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler; 463 PT_REGS_EAX(regs) = (unsigned long) sig; 464 PT_REGS_EDX(regs) = (unsigned long) &frame->info; 465 PT_REGS_ECX(regs) = (unsigned long) &frame->uc; 466 467 if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED)) 468 ptrace_notify(SIGTRAP); 469 return 0; 470 } 471 472 long sys_sigreturn(struct pt_regs *regs) 473 { 474 unsigned long sp = PT_REGS_SP(¤t->thread.regs); 475 struct sigframe __user *frame = (struct sigframe __user *)(sp - 8); 476 sigset_t set; 477 struct sigcontext __user *sc = &frame->sc; 478 unsigned long __user *oldmask = &sc->oldmask; 479 unsigned long __user *extramask = frame->extramask; 480 int sig_size = (_NSIG_WORDS - 1) * sizeof(unsigned long); 481 482 if (copy_from_user(&set.sig[0], oldmask, sizeof(set.sig[0])) || 483 copy_from_user(&set.sig[1], extramask, sig_size)) 484 goto segfault; 485 486 sigdelsetmask(&set, ~_BLOCKABLE); 487 set_current_blocked(&set); 488 489 if (copy_sc_from_user(¤t->thread.regs, sc)) 490 goto segfault; 491 492 /* Avoid ERESTART handling */ 493 PT_REGS_SYSCALL_NR(¤t->thread.regs) = -1; 494 return PT_REGS_SYSCALL_RET(¤t->thread.regs); 495 496 segfault: 497 force_sig(SIGSEGV, current); 498 return 0; 499 } 500 501 #else 502 503 struct rt_sigframe 504 { 505 char __user *pretcode; 506 struct ucontext uc; 507 struct siginfo info; 508 struct _fpstate fpstate; 509 }; 510 511 int setup_signal_stack_si(unsigned long stack_top, int sig, 512 struct k_sigaction *ka, struct pt_regs * regs, 513 siginfo_t *info, sigset_t *set) 514 { 515 struct rt_sigframe __user *frame; 516 int err = 0; 517 struct task_struct *me = current; 518 519 frame = (struct rt_sigframe __user *) 520 round_down(stack_top - sizeof(struct rt_sigframe), 16); 521 /* Subtract 128 for a red zone and 8 for proper alignment */ 522 frame = (struct rt_sigframe __user *) ((unsigned long) frame - 128 - 8); 523 524 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 525 goto out; 526 527 if (ka->sa.sa_flags & SA_SIGINFO) { 528 err |= copy_siginfo_to_user(&frame->info, info); 529 if (err) 530 goto out; 531 } 532 533 /* Create the ucontext. */ 534 err |= __put_user(0, &frame->uc.uc_flags); 535 err |= __put_user(0, &frame->uc.uc_link); 536 err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp); 537 err |= __put_user(sas_ss_flags(PT_REGS_SP(regs)), 538 &frame->uc.uc_stack.ss_flags); 539 err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size); 540 err |= copy_sc_to_user(&frame->uc.uc_mcontext, &frame->fpstate, regs, 541 set->sig[0]); 542 err |= __put_user(&frame->fpstate, &frame->uc.uc_mcontext.fpstate); 543 if (sizeof(*set) == 16) { 544 __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]); 545 __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]); 546 } 547 else 548 err |= __copy_to_user(&frame->uc.uc_sigmask, set, 549 sizeof(*set)); 550 551 /* 552 * Set up to return from userspace. If provided, use a stub 553 * already in userspace. 554 */ 555 /* x86-64 should always use SA_RESTORER. */ 556 if (ka->sa.sa_flags & SA_RESTORER) 557 err |= __put_user(ka->sa.sa_restorer, &frame->pretcode); 558 else 559 /* could use a vstub here */ 560 return err; 561 562 if (err) 563 return err; 564 565 /* Set up registers for signal handler */ 566 { 567 struct exec_domain *ed = current_thread_info()->exec_domain; 568 if (unlikely(ed && ed->signal_invmap && sig < 32)) 569 sig = ed->signal_invmap[sig]; 570 } 571 572 PT_REGS_SP(regs) = (unsigned long) frame; 573 PT_REGS_RDI(regs) = sig; 574 /* In case the signal handler was declared without prototypes */ 575 PT_REGS_RAX(regs) = 0; 576 577 /* 578 * This also works for non SA_SIGINFO handlers because they expect the 579 * next argument after the signal number on the stack. 580 */ 581 PT_REGS_RSI(regs) = (unsigned long) &frame->info; 582 PT_REGS_RDX(regs) = (unsigned long) &frame->uc; 583 PT_REGS_RIP(regs) = (unsigned long) ka->sa.sa_handler; 584 out: 585 return err; 586 } 587 #endif 588 589 long sys_rt_sigreturn(struct pt_regs *regs) 590 { 591 unsigned long sp = PT_REGS_SP(¤t->thread.regs); 592 struct rt_sigframe __user *frame = 593 (struct rt_sigframe __user *)(sp - sizeof(long)); 594 struct ucontext __user *uc = &frame->uc; 595 sigset_t set; 596 597 if (copy_from_user(&set, &uc->uc_sigmask, sizeof(set))) 598 goto segfault; 599 600 sigdelsetmask(&set, ~_BLOCKABLE); 601 set_current_blocked(&set); 602 603 if (copy_sc_from_user(¤t->thread.regs, &uc->uc_mcontext)) 604 goto segfault; 605 606 /* Avoid ERESTART handling */ 607 PT_REGS_SYSCALL_NR(¤t->thread.regs) = -1; 608 return PT_REGS_SYSCALL_RET(¤t->thread.regs); 609 610 segfault: 611 force_sig(SIGSEGV, current); 612 return 0; 613 } 614 615 #ifdef CONFIG_X86_32 616 long ptregs_sigreturn(void) 617 { 618 return sys_sigreturn(NULL); 619 } 620 long ptregs_rt_sigreturn(void) 621 { 622 return sys_rt_sigreturn(NULL); 623 } 624 #endif 625