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 <linux/syscalls.h> 12 #include <asm/unistd.h> 13 #include <linux/uaccess.h> 14 #include <asm/ucontext.h> 15 #include <frame_kern.h> 16 #include <registers.h> 17 #include <skas.h> 18 19 #ifdef CONFIG_X86_32 20 21 /* 22 * FPU tag word conversions. 23 */ 24 25 static inline unsigned short twd_i387_to_fxsr(unsigned short twd) 26 { 27 unsigned int tmp; /* to avoid 16 bit prefixes in the code */ 28 29 /* Transform each pair of bits into 01 (valid) or 00 (empty) */ 30 tmp = ~twd; 31 tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */ 32 /* and move the valid bits to the lower byte. */ 33 tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */ 34 tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */ 35 tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */ 36 return tmp; 37 } 38 39 static inline unsigned long twd_fxsr_to_i387(struct user_fxsr_struct *fxsave) 40 { 41 struct _fpxreg *st = NULL; 42 unsigned long twd = (unsigned long) fxsave->twd; 43 unsigned long tag; 44 unsigned long ret = 0xffff0000; 45 int i; 46 47 #define FPREG_ADDR(f, n) ((char *)&(f)->st_space + (n) * 16) 48 49 for (i = 0; i < 8; i++) { 50 if (twd & 0x1) { 51 st = (struct _fpxreg *) FPREG_ADDR(fxsave, i); 52 53 switch (st->exponent & 0x7fff) { 54 case 0x7fff: 55 tag = 2; /* Special */ 56 break; 57 case 0x0000: 58 if ( !st->significand[0] && 59 !st->significand[1] && 60 !st->significand[2] && 61 !st->significand[3] ) { 62 tag = 1; /* Zero */ 63 } else { 64 tag = 2; /* Special */ 65 } 66 break; 67 default: 68 if (st->significand[3] & 0x8000) { 69 tag = 0; /* Valid */ 70 } else { 71 tag = 2; /* Special */ 72 } 73 break; 74 } 75 } else { 76 tag = 3; /* Empty */ 77 } 78 ret |= (tag << (2 * i)); 79 twd = twd >> 1; 80 } 81 return ret; 82 } 83 84 static int convert_fxsr_to_user(struct _fpstate __user *buf, 85 struct user_fxsr_struct *fxsave) 86 { 87 unsigned long env[7]; 88 struct _fpreg __user *to; 89 struct _fpxreg *from; 90 int i; 91 92 env[0] = (unsigned long)fxsave->cwd | 0xffff0000ul; 93 env[1] = (unsigned long)fxsave->swd | 0xffff0000ul; 94 env[2] = twd_fxsr_to_i387(fxsave); 95 env[3] = fxsave->fip; 96 env[4] = fxsave->fcs | ((unsigned long)fxsave->fop << 16); 97 env[5] = fxsave->foo; 98 env[6] = fxsave->fos; 99 100 if (__copy_to_user(buf, env, 7 * sizeof(unsigned long))) 101 return 1; 102 103 to = &buf->_st[0]; 104 from = (struct _fpxreg *) &fxsave->st_space[0]; 105 for (i = 0; i < 8; i++, to++, from++) { 106 unsigned long __user *t = (unsigned long __user *)to; 107 unsigned long *f = (unsigned long *)from; 108 109 if (__put_user(*f, t) || 110 __put_user(*(f + 1), t + 1) || 111 __put_user(from->exponent, &to->exponent)) 112 return 1; 113 } 114 return 0; 115 } 116 117 static int convert_fxsr_from_user(struct user_fxsr_struct *fxsave, 118 struct _fpstate __user *buf) 119 { 120 unsigned long env[7]; 121 struct _fpxreg *to; 122 struct _fpreg __user *from; 123 int i; 124 125 if (copy_from_user( env, buf, 7 * sizeof(long))) 126 return 1; 127 128 fxsave->cwd = (unsigned short)(env[0] & 0xffff); 129 fxsave->swd = (unsigned short)(env[1] & 0xffff); 130 fxsave->twd = twd_i387_to_fxsr((unsigned short)(env[2] & 0xffff)); 131 fxsave->fip = env[3]; 132 fxsave->fop = (unsigned short)((env[4] & 0xffff0000ul) >> 16); 133 fxsave->fcs = (env[4] & 0xffff); 134 fxsave->foo = env[5]; 135 fxsave->fos = env[6]; 136 137 to = (struct _fpxreg *) &fxsave->st_space[0]; 138 from = &buf->_st[0]; 139 for (i = 0; i < 8; i++, to++, from++) { 140 unsigned long *t = (unsigned long *)to; 141 unsigned long __user *f = (unsigned long __user *)from; 142 143 if (__get_user(*t, f) || 144 __get_user(*(t + 1), f + 1) || 145 __get_user(to->exponent, &from->exponent)) 146 return 1; 147 } 148 return 0; 149 } 150 151 extern int have_fpx_regs; 152 153 #endif 154 155 static int copy_sc_from_user(struct pt_regs *regs, 156 struct sigcontext __user *from) 157 { 158 struct sigcontext sc; 159 int err; 160 161 /* Always make any pending restarted system calls return -EINTR */ 162 current->restart_block.fn = do_no_restart_syscall; 163 164 err = copy_from_user(&sc, from, sizeof(sc)); 165 if (err) 166 return err; 167 168 #define GETREG(regno, regname) regs->regs.gp[HOST_##regno] = sc.regname 169 170 #ifdef CONFIG_X86_32 171 GETREG(GS, gs); 172 GETREG(FS, fs); 173 GETREG(ES, es); 174 GETREG(DS, ds); 175 #endif 176 GETREG(DI, di); 177 GETREG(SI, si); 178 GETREG(BP, bp); 179 GETREG(SP, sp); 180 GETREG(BX, bx); 181 GETREG(DX, dx); 182 GETREG(CX, cx); 183 GETREG(AX, ax); 184 GETREG(IP, ip); 185 186 #ifdef CONFIG_X86_64 187 GETREG(R8, r8); 188 GETREG(R9, r9); 189 GETREG(R10, r10); 190 GETREG(R11, r11); 191 GETREG(R12, r12); 192 GETREG(R13, r13); 193 GETREG(R14, r14); 194 GETREG(R15, r15); 195 #endif 196 197 GETREG(CS, cs); 198 GETREG(EFLAGS, flags); 199 #ifdef CONFIG_X86_32 200 GETREG(SS, ss); 201 #endif 202 203 #undef GETREG 204 205 #ifdef CONFIG_X86_32 206 if (have_fpx_regs) { 207 struct user_fxsr_struct *fpx; 208 fpx = (void *)®s->regs.fp; 209 210 err = convert_fxsr_from_user(fpx, (void *)sc.fpstate); 211 if (err) 212 return 1; 213 } else { 214 BUILD_BUG_ON(sizeof(regs->regs.fp) > sizeof(struct _fpstate)); 215 err = copy_from_user(regs->regs.fp, (void *)sc.fpstate, 216 sizeof(regs->regs.fp)); 217 if (err) 218 return 1; 219 } 220 #else 221 { 222 /* FIXME: Save/restore extended state (past the 16 YMM regs) */ 223 BUILD_BUG_ON(sizeof(regs->regs.fp) < sizeof(struct _xstate)); 224 225 err = copy_from_user(regs->regs.fp, (void *)sc.fpstate, 226 sizeof(struct _xstate)); 227 if (err) 228 return 1; 229 } 230 #endif 231 return 0; 232 } 233 234 static int copy_sc_to_user(struct sigcontext __user *to, 235 struct _xstate __user *to_fp, struct pt_regs *regs, 236 unsigned long mask) 237 { 238 struct sigcontext sc; 239 struct faultinfo * fi = ¤t->thread.arch.faultinfo; 240 int err; 241 memset(&sc, 0, sizeof(struct sigcontext)); 242 243 #define PUTREG(regno, regname) sc.regname = regs->regs.gp[HOST_##regno] 244 245 #ifdef CONFIG_X86_32 246 PUTREG(GS, gs); 247 PUTREG(FS, fs); 248 PUTREG(ES, es); 249 PUTREG(DS, ds); 250 #endif 251 PUTREG(DI, di); 252 PUTREG(SI, si); 253 PUTREG(BP, bp); 254 PUTREG(SP, sp); 255 PUTREG(BX, bx); 256 PUTREG(DX, dx); 257 PUTREG(CX, cx); 258 PUTREG(AX, ax); 259 #ifdef CONFIG_X86_64 260 PUTREG(R8, r8); 261 PUTREG(R9, r9); 262 PUTREG(R10, r10); 263 PUTREG(R11, r11); 264 PUTREG(R12, r12); 265 PUTREG(R13, r13); 266 PUTREG(R14, r14); 267 PUTREG(R15, r15); 268 #endif 269 270 sc.cr2 = fi->cr2; 271 sc.err = fi->error_code; 272 sc.trapno = fi->trap_no; 273 PUTREG(IP, ip); 274 PUTREG(CS, cs); 275 PUTREG(EFLAGS, flags); 276 #ifdef CONFIG_X86_32 277 PUTREG(SP, sp_at_signal); 278 PUTREG(SS, ss); 279 #endif 280 #undef PUTREG 281 sc.oldmask = mask; 282 sc.fpstate = (unsigned long)to_fp; 283 284 err = copy_to_user(to, &sc, sizeof(struct sigcontext)); 285 if (err) 286 return 1; 287 288 #ifdef CONFIG_X86_32 289 if (have_fpx_regs) { 290 struct user_fxsr_struct *fpx; 291 292 fpx = (void *)®s->regs.fp; 293 294 err = convert_fxsr_to_user(&to_fp->fpstate, fpx); 295 if (err) 296 return 1; 297 298 err |= __put_user(fpx->swd, &to_fp->fpstate.status); 299 err |= __put_user(X86_FXSR_MAGIC, &to_fp->fpstate.magic); 300 if (err) 301 return 1; 302 303 } else { 304 if (copy_to_user(to_fp, regs->regs.fp, sizeof(regs->regs.fp))) 305 return 1; 306 307 /* Need to fill in the sw_reserved bits ... */ 308 BUILD_BUG_ON(offsetof(typeof(*to_fp), 309 fpstate.sw_reserved.magic1) >= 310 sizeof(struct _fpstate)); 311 __put_user(0, &to_fp->fpstate.sw_reserved.magic1); 312 __put_user(sizeof(struct _fpstate), 313 &to_fp->fpstate.sw_reserved.extended_size); 314 } 315 #else 316 if (copy_to_user(to_fp, regs->regs.fp, sizeof(struct _xstate))) 317 return 1; 318 #endif 319 320 return 0; 321 } 322 323 #ifdef CONFIG_X86_32 324 static int copy_ucontext_to_user(struct ucontext __user *uc, 325 struct _xstate __user *fp, sigset_t *set, 326 unsigned long sp) 327 { 328 int err = 0; 329 330 err |= __save_altstack(&uc->uc_stack, sp); 331 err |= copy_sc_to_user(&uc->uc_mcontext, fp, ¤t->thread.regs, 0); 332 err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set)); 333 return err; 334 } 335 336 struct sigframe 337 { 338 char __user *pretcode; 339 int sig; 340 struct sigcontext sc; 341 struct _xstate fpstate; 342 unsigned long extramask[_NSIG_WORDS-1]; 343 char retcode[8]; 344 }; 345 346 struct rt_sigframe 347 { 348 char __user *pretcode; 349 int sig; 350 struct siginfo __user *pinfo; 351 void __user *puc; 352 struct siginfo info; 353 struct ucontext uc; 354 struct _xstate fpstate; 355 char retcode[8]; 356 }; 357 358 int setup_signal_stack_sc(unsigned long stack_top, struct ksignal *ksig, 359 struct pt_regs *regs, sigset_t *mask) 360 { 361 struct sigframe __user *frame; 362 void __user *restorer; 363 int err = 0, sig = ksig->sig; 364 365 /* This is the same calculation as i386 - ((sp + 4) & 15) == 0 */ 366 stack_top = ((stack_top + 4) & -16UL) - 4; 367 frame = (struct sigframe __user *) stack_top - 1; 368 if (!access_ok(frame, sizeof(*frame))) 369 return 1; 370 371 restorer = frame->retcode; 372 if (ksig->ka.sa.sa_flags & SA_RESTORER) 373 restorer = ksig->ka.sa.sa_restorer; 374 375 err |= __put_user(restorer, &frame->pretcode); 376 err |= __put_user(sig, &frame->sig); 377 err |= copy_sc_to_user(&frame->sc, &frame->fpstate, regs, mask->sig[0]); 378 if (_NSIG_WORDS > 1) 379 err |= __copy_to_user(&frame->extramask, &mask->sig[1], 380 sizeof(frame->extramask)); 381 382 /* 383 * This is popl %eax ; movl $,%eax ; int $0x80 384 * 385 * WE DO NOT USE IT ANY MORE! It's only left here for historical 386 * reasons and because gdb uses it as a signature to notice 387 * signal handler stack frames. 388 */ 389 err |= __put_user(0xb858, (short __user *)(frame->retcode+0)); 390 err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2)); 391 err |= __put_user(0x80cd, (short __user *)(frame->retcode+6)); 392 393 if (err) 394 return err; 395 396 PT_REGS_SP(regs) = (unsigned long) frame; 397 PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler; 398 PT_REGS_AX(regs) = (unsigned long) sig; 399 PT_REGS_DX(regs) = (unsigned long) 0; 400 PT_REGS_CX(regs) = (unsigned long) 0; 401 return 0; 402 } 403 404 int setup_signal_stack_si(unsigned long stack_top, struct ksignal *ksig, 405 struct pt_regs *regs, sigset_t *mask) 406 { 407 struct rt_sigframe __user *frame; 408 void __user *restorer; 409 int err = 0, sig = ksig->sig; 410 411 stack_top &= -8UL; 412 frame = (struct rt_sigframe __user *) stack_top - 1; 413 if (!access_ok(frame, sizeof(*frame))) 414 return 1; 415 416 restorer = frame->retcode; 417 if (ksig->ka.sa.sa_flags & SA_RESTORER) 418 restorer = ksig->ka.sa.sa_restorer; 419 420 err |= __put_user(restorer, &frame->pretcode); 421 err |= __put_user(sig, &frame->sig); 422 err |= __put_user(&frame->info, &frame->pinfo); 423 err |= __put_user(&frame->uc, &frame->puc); 424 err |= copy_siginfo_to_user(&frame->info, &ksig->info); 425 err |= copy_ucontext_to_user(&frame->uc, &frame->fpstate, mask, 426 PT_REGS_SP(regs)); 427 428 /* 429 * This is movl $,%eax ; int $0x80 430 * 431 * WE DO NOT USE IT ANY MORE! It's only left here for historical 432 * reasons and because gdb uses it as a signature to notice 433 * signal handler stack frames. 434 */ 435 err |= __put_user(0xb8, (char __user *)(frame->retcode+0)); 436 err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1)); 437 err |= __put_user(0x80cd, (short __user *)(frame->retcode+5)); 438 439 if (err) 440 return err; 441 442 PT_REGS_SP(regs) = (unsigned long) frame; 443 PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler; 444 PT_REGS_AX(regs) = (unsigned long) sig; 445 PT_REGS_DX(regs) = (unsigned long) &frame->info; 446 PT_REGS_CX(regs) = (unsigned long) &frame->uc; 447 return 0; 448 } 449 450 SYSCALL_DEFINE0(sigreturn) 451 { 452 unsigned long sp = PT_REGS_SP(¤t->thread.regs); 453 struct sigframe __user *frame = (struct sigframe __user *)(sp - 8); 454 sigset_t set; 455 struct sigcontext __user *sc = &frame->sc; 456 int sig_size = (_NSIG_WORDS - 1) * sizeof(unsigned long); 457 458 if (copy_from_user(&set.sig[0], &sc->oldmask, sizeof(set.sig[0])) || 459 copy_from_user(&set.sig[1], frame->extramask, sig_size)) 460 goto segfault; 461 462 set_current_blocked(&set); 463 464 if (copy_sc_from_user(¤t->thread.regs, sc)) 465 goto segfault; 466 467 /* Avoid ERESTART handling */ 468 PT_REGS_SYSCALL_NR(¤t->thread.regs) = -1; 469 return PT_REGS_SYSCALL_RET(¤t->thread.regs); 470 471 segfault: 472 force_sig(SIGSEGV); 473 return 0; 474 } 475 476 #else 477 478 struct rt_sigframe 479 { 480 char __user *pretcode; 481 struct ucontext uc; 482 struct siginfo info; 483 struct _xstate fpstate; 484 }; 485 486 int setup_signal_stack_si(unsigned long stack_top, struct ksignal *ksig, 487 struct pt_regs *regs, sigset_t *set) 488 { 489 struct rt_sigframe __user *frame; 490 int err = 0, sig = ksig->sig; 491 unsigned long fp_to; 492 493 frame = (struct rt_sigframe __user *) 494 round_down(stack_top - sizeof(struct rt_sigframe), 16); 495 /* Subtract 128 for a red zone and 8 for proper alignment */ 496 frame = (struct rt_sigframe __user *) ((unsigned long) frame - 128 - 8); 497 498 if (!access_ok(frame, sizeof(*frame))) 499 goto out; 500 501 if (ksig->ka.sa.sa_flags & SA_SIGINFO) { 502 err |= copy_siginfo_to_user(&frame->info, &ksig->info); 503 if (err) 504 goto out; 505 } 506 507 /* Create the ucontext. */ 508 err |= __put_user(0, &frame->uc.uc_flags); 509 err |= __put_user(0, &frame->uc.uc_link); 510 err |= __save_altstack(&frame->uc.uc_stack, PT_REGS_SP(regs)); 511 err |= copy_sc_to_user(&frame->uc.uc_mcontext, &frame->fpstate, regs, 512 set->sig[0]); 513 514 fp_to = (unsigned long)&frame->fpstate; 515 516 err |= __put_user(fp_to, &frame->uc.uc_mcontext.fpstate); 517 if (sizeof(*set) == 16) { 518 err |= __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]); 519 err |= __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]); 520 } 521 else 522 err |= __copy_to_user(&frame->uc.uc_sigmask, set, 523 sizeof(*set)); 524 525 /* 526 * Set up to return from userspace. If provided, use a stub 527 * already in userspace. 528 */ 529 /* x86-64 should always use SA_RESTORER. */ 530 if (ksig->ka.sa.sa_flags & SA_RESTORER) 531 err |= __put_user((void *)ksig->ka.sa.sa_restorer, 532 &frame->pretcode); 533 else 534 /* could use a vstub here */ 535 return err; 536 537 if (err) 538 return err; 539 540 PT_REGS_SP(regs) = (unsigned long) frame; 541 PT_REGS_DI(regs) = sig; 542 /* In case the signal handler was declared without prototypes */ 543 PT_REGS_AX(regs) = 0; 544 545 /* 546 * This also works for non SA_SIGINFO handlers because they expect the 547 * next argument after the signal number on the stack. 548 */ 549 PT_REGS_SI(regs) = (unsigned long) &frame->info; 550 PT_REGS_DX(regs) = (unsigned long) &frame->uc; 551 PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler; 552 out: 553 return err; 554 } 555 #endif 556 557 SYSCALL_DEFINE0(rt_sigreturn) 558 { 559 unsigned long sp = PT_REGS_SP(¤t->thread.regs); 560 struct rt_sigframe __user *frame = 561 (struct rt_sigframe __user *)(sp - sizeof(long)); 562 struct ucontext __user *uc = &frame->uc; 563 sigset_t set; 564 565 if (copy_from_user(&set, &uc->uc_sigmask, sizeof(set))) 566 goto segfault; 567 568 set_current_blocked(&set); 569 570 if (copy_sc_from_user(¤t->thread.regs, &uc->uc_mcontext)) 571 goto segfault; 572 573 /* Avoid ERESTART handling */ 574 PT_REGS_SYSCALL_NR(¤t->thread.regs) = -1; 575 return PT_REGS_SYSCALL_RET(¤t->thread.regs); 576 577 segfault: 578 force_sig(SIGSEGV); 579 return 0; 580 } 581