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 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, (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 } 235 236 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_32 326 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 }; 359 360 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(VERIFY_WRITE, 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 } 405 406 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(VERIFY_WRITE, 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 } 451 452 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, current); 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 }; 487 488 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(VERIFY_WRITE, 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 558 559 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, current); 581 return 0; 582 } 583