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_thread_info()->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 |= put_user(current->sas_ss_sp, &uc->uc_stack.ss_sp); 346 err |= put_user(sas_ss_flags(sp), &uc->uc_stack.ss_flags); 347 err |= put_user(current->sas_ss_size, &uc->uc_stack.ss_size); 348 err |= copy_sc_to_user(&uc->uc_mcontext, fp, ¤t->thread.regs, 0); 349 err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set)); 350 return err; 351 } 352 353 struct sigframe 354 { 355 char __user *pretcode; 356 int sig; 357 struct sigcontext sc; 358 struct _fpstate fpstate; 359 unsigned long extramask[_NSIG_WORDS-1]; 360 char retcode[8]; 361 }; 362 363 struct rt_sigframe 364 { 365 char __user *pretcode; 366 int sig; 367 struct siginfo __user *pinfo; 368 void __user *puc; 369 struct siginfo info; 370 struct ucontext uc; 371 struct _fpstate fpstate; 372 char retcode[8]; 373 }; 374 375 int setup_signal_stack_sc(unsigned long stack_top, int sig, 376 struct k_sigaction *ka, struct pt_regs *regs, 377 sigset_t *mask) 378 { 379 struct sigframe __user *frame; 380 void __user *restorer; 381 int err = 0; 382 383 /* This is the same calculation as i386 - ((sp + 4) & 15) == 0 */ 384 stack_top = ((stack_top + 4) & -16UL) - 4; 385 frame = (struct sigframe __user *) stack_top - 1; 386 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 387 return 1; 388 389 restorer = frame->retcode; 390 if (ka->sa.sa_flags & SA_RESTORER) 391 restorer = ka->sa.sa_restorer; 392 393 err |= __put_user(restorer, &frame->pretcode); 394 err |= __put_user(sig, &frame->sig); 395 err |= copy_sc_to_user(&frame->sc, &frame->fpstate, regs, mask->sig[0]); 396 if (_NSIG_WORDS > 1) 397 err |= __copy_to_user(&frame->extramask, &mask->sig[1], 398 sizeof(frame->extramask)); 399 400 /* 401 * This is popl %eax ; movl $,%eax ; int $0x80 402 * 403 * WE DO NOT USE IT ANY MORE! It's only left here for historical 404 * reasons and because gdb uses it as a signature to notice 405 * signal handler stack frames. 406 */ 407 err |= __put_user(0xb858, (short __user *)(frame->retcode+0)); 408 err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2)); 409 err |= __put_user(0x80cd, (short __user *)(frame->retcode+6)); 410 411 if (err) 412 return err; 413 414 PT_REGS_SP(regs) = (unsigned long) frame; 415 PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler; 416 PT_REGS_AX(regs) = (unsigned long) sig; 417 PT_REGS_DX(regs) = (unsigned long) 0; 418 PT_REGS_CX(regs) = (unsigned long) 0; 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_AX(regs) = (unsigned long) sig; 464 PT_REGS_DX(regs) = (unsigned long) &frame->info; 465 PT_REGS_CX(regs) = (unsigned long) &frame->uc; 466 return 0; 467 } 468 469 long sys_sigreturn(struct pt_regs *regs) 470 { 471 unsigned long sp = PT_REGS_SP(¤t->thread.regs); 472 struct sigframe __user *frame = (struct sigframe __user *)(sp - 8); 473 sigset_t set; 474 struct sigcontext __user *sc = &frame->sc; 475 unsigned long __user *oldmask = &sc->oldmask; 476 unsigned long __user *extramask = frame->extramask; 477 int sig_size = (_NSIG_WORDS - 1) * sizeof(unsigned long); 478 479 if (copy_from_user(&set.sig[0], oldmask, sizeof(set.sig[0])) || 480 copy_from_user(&set.sig[1], extramask, sig_size)) 481 goto segfault; 482 483 set_current_blocked(&set); 484 485 if (copy_sc_from_user(¤t->thread.regs, sc)) 486 goto segfault; 487 488 /* Avoid ERESTART handling */ 489 PT_REGS_SYSCALL_NR(¤t->thread.regs) = -1; 490 return PT_REGS_SYSCALL_RET(¤t->thread.regs); 491 492 segfault: 493 force_sig(SIGSEGV, current); 494 return 0; 495 } 496 497 #else 498 499 struct rt_sigframe 500 { 501 char __user *pretcode; 502 struct ucontext uc; 503 struct siginfo info; 504 struct _fpstate fpstate; 505 }; 506 507 int setup_signal_stack_si(unsigned long stack_top, int sig, 508 struct k_sigaction *ka, struct pt_regs * regs, 509 siginfo_t *info, sigset_t *set) 510 { 511 struct rt_sigframe __user *frame; 512 int err = 0; 513 struct task_struct *me = current; 514 515 frame = (struct rt_sigframe __user *) 516 round_down(stack_top - sizeof(struct rt_sigframe), 16); 517 /* Subtract 128 for a red zone and 8 for proper alignment */ 518 frame = (struct rt_sigframe __user *) ((unsigned long) frame - 128 - 8); 519 520 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 521 goto out; 522 523 if (ka->sa.sa_flags & SA_SIGINFO) { 524 err |= copy_siginfo_to_user(&frame->info, info); 525 if (err) 526 goto out; 527 } 528 529 /* Create the ucontext. */ 530 err |= __put_user(0, &frame->uc.uc_flags); 531 err |= __put_user(0, &frame->uc.uc_link); 532 err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp); 533 err |= __put_user(sas_ss_flags(PT_REGS_SP(regs)), 534 &frame->uc.uc_stack.ss_flags); 535 err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size); 536 err |= copy_sc_to_user(&frame->uc.uc_mcontext, &frame->fpstate, regs, 537 set->sig[0]); 538 err |= __put_user(&frame->fpstate, &frame->uc.uc_mcontext.fpstate); 539 if (sizeof(*set) == 16) { 540 err |= __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]); 541 err |= __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]); 542 } 543 else 544 err |= __copy_to_user(&frame->uc.uc_sigmask, set, 545 sizeof(*set)); 546 547 /* 548 * Set up to return from userspace. If provided, use a stub 549 * already in userspace. 550 */ 551 /* x86-64 should always use SA_RESTORER. */ 552 if (ka->sa.sa_flags & SA_RESTORER) 553 err |= __put_user(ka->sa.sa_restorer, &frame->pretcode); 554 else 555 /* could use a vstub here */ 556 return err; 557 558 if (err) 559 return err; 560 561 /* Set up registers for signal handler */ 562 { 563 struct exec_domain *ed = current_thread_info()->exec_domain; 564 if (unlikely(ed && ed->signal_invmap && sig < 32)) 565 sig = ed->signal_invmap[sig]; 566 } 567 568 PT_REGS_SP(regs) = (unsigned long) frame; 569 PT_REGS_DI(regs) = sig; 570 /* In case the signal handler was declared without prototypes */ 571 PT_REGS_AX(regs) = 0; 572 573 /* 574 * This also works for non SA_SIGINFO handlers because they expect the 575 * next argument after the signal number on the stack. 576 */ 577 PT_REGS_SI(regs) = (unsigned long) &frame->info; 578 PT_REGS_DX(regs) = (unsigned long) &frame->uc; 579 PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler; 580 out: 581 return err; 582 } 583 #endif 584 585 long sys_rt_sigreturn(struct pt_regs *regs) 586 { 587 unsigned long sp = PT_REGS_SP(¤t->thread.regs); 588 struct rt_sigframe __user *frame = 589 (struct rt_sigframe __user *)(sp - sizeof(long)); 590 struct ucontext __user *uc = &frame->uc; 591 sigset_t set; 592 593 if (copy_from_user(&set, &uc->uc_sigmask, sizeof(set))) 594 goto segfault; 595 596 set_current_blocked(&set); 597 598 if (copy_sc_from_user(¤t->thread.regs, &uc->uc_mcontext)) 599 goto segfault; 600 601 /* Avoid ERESTART handling */ 602 PT_REGS_SYSCALL_NR(¤t->thread.regs) = -1; 603 return PT_REGS_SYSCALL_RET(¤t->thread.regs); 604 605 segfault: 606 force_sig(SIGSEGV, current); 607 return 0; 608 } 609 610 #ifdef CONFIG_X86_32 611 long ptregs_sigreturn(void) 612 { 613 return sys_sigreturn(NULL); 614 } 615 long ptregs_rt_sigreturn(void) 616 { 617 return sys_rt_sigreturn(NULL); 618 } 619 #endif 620