1 /* 2 * arch/sparc64/kernel/signal.c 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 * Copyright (C) 1995, 2008 David S. Miller (davem@davemloft.net) 6 * Copyright (C) 1996 Miguel de Icaza (miguel@nuclecu.unam.mx) 7 * Copyright (C) 1997 Eddie C. Dost (ecd@skynet.be) 8 * Copyright (C) 1997,1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz) 9 */ 10 11 #ifdef CONFIG_COMPAT 12 #include <linux/compat.h> /* for compat_old_sigset_t */ 13 #endif 14 #include <linux/sched.h> 15 #include <linux/kernel.h> 16 #include <linux/signal.h> 17 #include <linux/errno.h> 18 #include <linux/wait.h> 19 #include <linux/ptrace.h> 20 #include <linux/tracehook.h> 21 #include <linux/unistd.h> 22 #include <linux/mm.h> 23 #include <linux/tty.h> 24 #include <linux/binfmts.h> 25 #include <linux/bitops.h> 26 #include <linux/context_tracking.h> 27 28 #include <linux/uaccess.h> 29 #include <asm/ptrace.h> 30 #include <asm/pgtable.h> 31 #include <asm/fpumacro.h> 32 #include <asm/uctx.h> 33 #include <asm/siginfo.h> 34 #include <asm/visasm.h> 35 #include <asm/switch_to.h> 36 #include <asm/cacheflush.h> 37 38 #include "sigutil.h" 39 #include "systbls.h" 40 #include "kernel.h" 41 #include "entry.h" 42 43 /* {set, get}context() needed for 64-bit SparcLinux userland. */ 44 asmlinkage void sparc64_set_context(struct pt_regs *regs) 45 { 46 struct ucontext __user *ucp = (struct ucontext __user *) 47 regs->u_regs[UREG_I0]; 48 enum ctx_state prev_state = exception_enter(); 49 mc_gregset_t __user *grp; 50 unsigned long pc, npc, tstate; 51 unsigned long fp, i7; 52 unsigned char fenab; 53 int err; 54 55 synchronize_user_stack(); 56 if (get_thread_wsaved() || 57 (((unsigned long)ucp) & (sizeof(unsigned long)-1)) || 58 (!__access_ok(ucp, sizeof(*ucp)))) 59 goto do_sigsegv; 60 grp = &ucp->uc_mcontext.mc_gregs; 61 err = __get_user(pc, &((*grp)[MC_PC])); 62 err |= __get_user(npc, &((*grp)[MC_NPC])); 63 if (err || ((pc | npc) & 3)) 64 goto do_sigsegv; 65 if (regs->u_regs[UREG_I1]) { 66 sigset_t set; 67 68 if (_NSIG_WORDS == 1) { 69 if (__get_user(set.sig[0], &ucp->uc_sigmask.sig[0])) 70 goto do_sigsegv; 71 } else { 72 if (__copy_from_user(&set, &ucp->uc_sigmask, sizeof(sigset_t))) 73 goto do_sigsegv; 74 } 75 set_current_blocked(&set); 76 } 77 if (test_thread_flag(TIF_32BIT)) { 78 pc &= 0xffffffff; 79 npc &= 0xffffffff; 80 } 81 regs->tpc = pc; 82 regs->tnpc = npc; 83 err |= __get_user(regs->y, &((*grp)[MC_Y])); 84 err |= __get_user(tstate, &((*grp)[MC_TSTATE])); 85 regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC); 86 regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC)); 87 err |= __get_user(regs->u_regs[UREG_G1], (&(*grp)[MC_G1])); 88 err |= __get_user(regs->u_regs[UREG_G2], (&(*grp)[MC_G2])); 89 err |= __get_user(regs->u_regs[UREG_G3], (&(*grp)[MC_G3])); 90 err |= __get_user(regs->u_regs[UREG_G4], (&(*grp)[MC_G4])); 91 err |= __get_user(regs->u_regs[UREG_G5], (&(*grp)[MC_G5])); 92 err |= __get_user(regs->u_regs[UREG_G6], (&(*grp)[MC_G6])); 93 94 /* Skip %g7 as that's the thread register in userspace. */ 95 96 err |= __get_user(regs->u_regs[UREG_I0], (&(*grp)[MC_O0])); 97 err |= __get_user(regs->u_regs[UREG_I1], (&(*grp)[MC_O1])); 98 err |= __get_user(regs->u_regs[UREG_I2], (&(*grp)[MC_O2])); 99 err |= __get_user(regs->u_regs[UREG_I3], (&(*grp)[MC_O3])); 100 err |= __get_user(regs->u_regs[UREG_I4], (&(*grp)[MC_O4])); 101 err |= __get_user(regs->u_regs[UREG_I5], (&(*grp)[MC_O5])); 102 err |= __get_user(regs->u_regs[UREG_I6], (&(*grp)[MC_O6])); 103 err |= __get_user(regs->u_regs[UREG_I7], (&(*grp)[MC_O7])); 104 105 err |= __get_user(fp, &(ucp->uc_mcontext.mc_fp)); 106 err |= __get_user(i7, &(ucp->uc_mcontext.mc_i7)); 107 err |= __put_user(fp, 108 (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[6]))); 109 err |= __put_user(i7, 110 (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[7]))); 111 112 err |= __get_user(fenab, &(ucp->uc_mcontext.mc_fpregs.mcfpu_enab)); 113 if (fenab) { 114 unsigned long *fpregs = current_thread_info()->fpregs; 115 unsigned long fprs; 116 117 fprs_write(0); 118 err |= __get_user(fprs, &(ucp->uc_mcontext.mc_fpregs.mcfpu_fprs)); 119 if (fprs & FPRS_DL) 120 err |= copy_from_user(fpregs, 121 &(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs), 122 (sizeof(unsigned int) * 32)); 123 if (fprs & FPRS_DU) 124 err |= copy_from_user(fpregs+16, 125 ((unsigned long __user *)&(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs))+16, 126 (sizeof(unsigned int) * 32)); 127 err |= __get_user(current_thread_info()->xfsr[0], 128 &(ucp->uc_mcontext.mc_fpregs.mcfpu_fsr)); 129 err |= __get_user(current_thread_info()->gsr[0], 130 &(ucp->uc_mcontext.mc_fpregs.mcfpu_gsr)); 131 regs->tstate &= ~TSTATE_PEF; 132 } 133 if (err) 134 goto do_sigsegv; 135 out: 136 exception_exit(prev_state); 137 return; 138 do_sigsegv: 139 force_sig(SIGSEGV, current); 140 goto out; 141 } 142 143 asmlinkage void sparc64_get_context(struct pt_regs *regs) 144 { 145 struct ucontext __user *ucp = (struct ucontext __user *) 146 regs->u_regs[UREG_I0]; 147 enum ctx_state prev_state = exception_enter(); 148 mc_gregset_t __user *grp; 149 mcontext_t __user *mcp; 150 unsigned long fp, i7; 151 unsigned char fenab; 152 int err; 153 154 synchronize_user_stack(); 155 if (get_thread_wsaved() || clear_user(ucp, sizeof(*ucp))) 156 goto do_sigsegv; 157 158 #if 1 159 fenab = 0; /* IMO get_context is like any other system call, thus modifies FPU state -jj */ 160 #else 161 fenab = (current_thread_info()->fpsaved[0] & FPRS_FEF); 162 #endif 163 164 mcp = &ucp->uc_mcontext; 165 grp = &mcp->mc_gregs; 166 167 /* Skip over the trap instruction, first. */ 168 if (test_thread_flag(TIF_32BIT)) { 169 regs->tpc = (regs->tnpc & 0xffffffff); 170 regs->tnpc = (regs->tnpc + 4) & 0xffffffff; 171 } else { 172 regs->tpc = regs->tnpc; 173 regs->tnpc += 4; 174 } 175 err = 0; 176 if (_NSIG_WORDS == 1) 177 err |= __put_user(current->blocked.sig[0], 178 (unsigned long __user *)&ucp->uc_sigmask); 179 else 180 err |= __copy_to_user(&ucp->uc_sigmask, ¤t->blocked, 181 sizeof(sigset_t)); 182 183 err |= __put_user(regs->tstate, &((*grp)[MC_TSTATE])); 184 err |= __put_user(regs->tpc, &((*grp)[MC_PC])); 185 err |= __put_user(regs->tnpc, &((*grp)[MC_NPC])); 186 err |= __put_user(regs->y, &((*grp)[MC_Y])); 187 err |= __put_user(regs->u_regs[UREG_G1], &((*grp)[MC_G1])); 188 err |= __put_user(regs->u_regs[UREG_G2], &((*grp)[MC_G2])); 189 err |= __put_user(regs->u_regs[UREG_G3], &((*grp)[MC_G3])); 190 err |= __put_user(regs->u_regs[UREG_G4], &((*grp)[MC_G4])); 191 err |= __put_user(regs->u_regs[UREG_G5], &((*grp)[MC_G5])); 192 err |= __put_user(regs->u_regs[UREG_G6], &((*grp)[MC_G6])); 193 err |= __put_user(regs->u_regs[UREG_G7], &((*grp)[MC_G7])); 194 err |= __put_user(regs->u_regs[UREG_I0], &((*grp)[MC_O0])); 195 err |= __put_user(regs->u_regs[UREG_I1], &((*grp)[MC_O1])); 196 err |= __put_user(regs->u_regs[UREG_I2], &((*grp)[MC_O2])); 197 err |= __put_user(regs->u_regs[UREG_I3], &((*grp)[MC_O3])); 198 err |= __put_user(regs->u_regs[UREG_I4], &((*grp)[MC_O4])); 199 err |= __put_user(regs->u_regs[UREG_I5], &((*grp)[MC_O5])); 200 err |= __put_user(regs->u_regs[UREG_I6], &((*grp)[MC_O6])); 201 err |= __put_user(regs->u_regs[UREG_I7], &((*grp)[MC_O7])); 202 203 err |= __get_user(fp, 204 (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[6]))); 205 err |= __get_user(i7, 206 (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[7]))); 207 err |= __put_user(fp, &(mcp->mc_fp)); 208 err |= __put_user(i7, &(mcp->mc_i7)); 209 210 err |= __put_user(fenab, &(mcp->mc_fpregs.mcfpu_enab)); 211 if (fenab) { 212 unsigned long *fpregs = current_thread_info()->fpregs; 213 unsigned long fprs; 214 215 fprs = current_thread_info()->fpsaved[0]; 216 if (fprs & FPRS_DL) 217 err |= copy_to_user(&(mcp->mc_fpregs.mcfpu_fregs), fpregs, 218 (sizeof(unsigned int) * 32)); 219 if (fprs & FPRS_DU) 220 err |= copy_to_user( 221 ((unsigned long __user *)&(mcp->mc_fpregs.mcfpu_fregs))+16, fpregs+16, 222 (sizeof(unsigned int) * 32)); 223 err |= __put_user(current_thread_info()->xfsr[0], &(mcp->mc_fpregs.mcfpu_fsr)); 224 err |= __put_user(current_thread_info()->gsr[0], &(mcp->mc_fpregs.mcfpu_gsr)); 225 err |= __put_user(fprs, &(mcp->mc_fpregs.mcfpu_fprs)); 226 } 227 if (err) 228 goto do_sigsegv; 229 out: 230 exception_exit(prev_state); 231 return; 232 do_sigsegv: 233 force_sig(SIGSEGV, current); 234 goto out; 235 } 236 237 /* Checks if the fp is valid. We always build rt signal frames which 238 * are 16-byte aligned, therefore we can always enforce that the 239 * restore frame has that property as well. 240 */ 241 static bool invalid_frame_pointer(void __user *fp) 242 { 243 if (((unsigned long) fp) & 15) 244 return true; 245 return false; 246 } 247 248 struct rt_signal_frame { 249 struct sparc_stackf ss; 250 siginfo_t info; 251 struct pt_regs regs; 252 __siginfo_fpu_t __user *fpu_save; 253 stack_t stack; 254 sigset_t mask; 255 __siginfo_rwin_t *rwin_save; 256 }; 257 258 void do_rt_sigreturn(struct pt_regs *regs) 259 { 260 unsigned long tpc, tnpc, tstate, ufp; 261 struct rt_signal_frame __user *sf; 262 __siginfo_fpu_t __user *fpu_save; 263 __siginfo_rwin_t __user *rwin_save; 264 sigset_t set; 265 int err; 266 267 /* Always make any pending restarted system calls return -EINTR */ 268 current->restart_block.fn = do_no_restart_syscall; 269 270 synchronize_user_stack (); 271 sf = (struct rt_signal_frame __user *) 272 (regs->u_regs [UREG_FP] + STACK_BIAS); 273 274 /* 1. Make sure we are not getting garbage from the user */ 275 if (invalid_frame_pointer(sf)) 276 goto segv; 277 278 if (get_user(ufp, &sf->regs.u_regs[UREG_FP])) 279 goto segv; 280 281 if ((ufp + STACK_BIAS) & 0x7) 282 goto segv; 283 284 err = __get_user(tpc, &sf->regs.tpc); 285 err |= __get_user(tnpc, &sf->regs.tnpc); 286 if (test_thread_flag(TIF_32BIT)) { 287 tpc &= 0xffffffff; 288 tnpc &= 0xffffffff; 289 } 290 err |= ((tpc | tnpc) & 3); 291 292 /* 2. Restore the state */ 293 err |= __get_user(regs->y, &sf->regs.y); 294 err |= __get_user(tstate, &sf->regs.tstate); 295 err |= copy_from_user(regs->u_regs, sf->regs.u_regs, sizeof(regs->u_regs)); 296 297 /* User can only change condition codes and %asi in %tstate. */ 298 regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC); 299 regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC)); 300 301 err |= __get_user(fpu_save, &sf->fpu_save); 302 if (!err && fpu_save) 303 err |= restore_fpu_state(regs, fpu_save); 304 305 err |= __copy_from_user(&set, &sf->mask, sizeof(sigset_t)); 306 err |= restore_altstack(&sf->stack); 307 if (err) 308 goto segv; 309 310 err |= __get_user(rwin_save, &sf->rwin_save); 311 if (!err && rwin_save) { 312 if (restore_rwin_state(rwin_save)) 313 goto segv; 314 } 315 316 regs->tpc = tpc; 317 regs->tnpc = tnpc; 318 319 /* Prevent syscall restart. */ 320 pt_regs_clear_syscall(regs); 321 322 set_current_blocked(&set); 323 return; 324 segv: 325 force_sig(SIGSEGV, current); 326 } 327 328 static inline void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, unsigned long framesize) 329 { 330 unsigned long sp = regs->u_regs[UREG_FP] + STACK_BIAS; 331 332 /* 333 * If we are on the alternate signal stack and would overflow it, don't. 334 * Return an always-bogus address instead so we will die with SIGSEGV. 335 */ 336 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize))) 337 return (void __user *) -1L; 338 339 /* This is the X/Open sanctioned signal stack switching. */ 340 sp = sigsp(sp, ksig) - framesize; 341 342 /* Always align the stack frame. This handles two cases. First, 343 * sigaltstack need not be mindful of platform specific stack 344 * alignment. Second, if we took this signal because the stack 345 * is not aligned properly, we'd like to take the signal cleanly 346 * and report that. 347 */ 348 sp &= ~15UL; 349 350 return (void __user *) sp; 351 } 352 353 static inline int 354 setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) 355 { 356 struct rt_signal_frame __user *sf; 357 int wsaved, err, sf_size; 358 void __user *tail; 359 360 /* 1. Make sure everything is clean */ 361 synchronize_user_stack(); 362 save_and_clear_fpu(); 363 364 wsaved = get_thread_wsaved(); 365 366 sf_size = sizeof(struct rt_signal_frame); 367 if (current_thread_info()->fpsaved[0] & FPRS_FEF) 368 sf_size += sizeof(__siginfo_fpu_t); 369 if (wsaved) 370 sf_size += sizeof(__siginfo_rwin_t); 371 sf = (struct rt_signal_frame __user *) 372 get_sigframe(ksig, regs, sf_size); 373 374 if (invalid_frame_pointer (sf)) { 375 do_exit(SIGILL); /* won't return, actually */ 376 return -EINVAL; 377 } 378 379 tail = (sf + 1); 380 381 /* 2. Save the current process state */ 382 err = copy_to_user(&sf->regs, regs, sizeof (*regs)); 383 384 if (current_thread_info()->fpsaved[0] & FPRS_FEF) { 385 __siginfo_fpu_t __user *fpu_save = tail; 386 tail += sizeof(__siginfo_fpu_t); 387 err |= save_fpu_state(regs, fpu_save); 388 err |= __put_user((u64)fpu_save, &sf->fpu_save); 389 } else { 390 err |= __put_user(0, &sf->fpu_save); 391 } 392 if (wsaved) { 393 __siginfo_rwin_t __user *rwin_save = tail; 394 tail += sizeof(__siginfo_rwin_t); 395 err |= save_rwin_state(wsaved, rwin_save); 396 err |= __put_user((u64)rwin_save, &sf->rwin_save); 397 set_thread_wsaved(0); 398 } else { 399 err |= __put_user(0, &sf->rwin_save); 400 } 401 402 /* Setup sigaltstack */ 403 err |= __save_altstack(&sf->stack, regs->u_regs[UREG_FP]); 404 405 err |= copy_to_user(&sf->mask, sigmask_to_save(), sizeof(sigset_t)); 406 407 if (!wsaved) { 408 err |= copy_in_user((u64 __user *)sf, 409 (u64 __user *)(regs->u_regs[UREG_FP] + 410 STACK_BIAS), 411 sizeof(struct reg_window)); 412 } else { 413 struct reg_window *rp; 414 415 rp = ¤t_thread_info()->reg_window[wsaved - 1]; 416 err |= copy_to_user(sf, rp, sizeof(struct reg_window)); 417 } 418 if (ksig->ka.sa.sa_flags & SA_SIGINFO) 419 err |= copy_siginfo_to_user(&sf->info, &ksig->info); 420 else { 421 err |= __put_user(ksig->sig, &sf->info.si_signo); 422 err |= __put_user(SI_NOINFO, &sf->info.si_code); 423 } 424 if (err) 425 return err; 426 427 /* 3. signal handler back-trampoline and parameters */ 428 regs->u_regs[UREG_FP] = ((unsigned long) sf) - STACK_BIAS; 429 regs->u_regs[UREG_I0] = ksig->sig; 430 regs->u_regs[UREG_I1] = (unsigned long) &sf->info; 431 432 /* The sigcontext is passed in this way because of how it 433 * is defined in GLIBC's /usr/include/bits/sigcontext.h 434 * for sparc64. It includes the 128 bytes of siginfo_t. 435 */ 436 regs->u_regs[UREG_I2] = (unsigned long) &sf->info; 437 438 /* 5. signal handler */ 439 regs->tpc = (unsigned long) ksig->ka.sa.sa_handler; 440 regs->tnpc = (regs->tpc + 4); 441 if (test_thread_flag(TIF_32BIT)) { 442 regs->tpc &= 0xffffffff; 443 regs->tnpc &= 0xffffffff; 444 } 445 /* 4. return to kernel instructions */ 446 regs->u_regs[UREG_I7] = (unsigned long)ksig->ka.ka_restorer; 447 return 0; 448 } 449 450 static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs, 451 struct sigaction *sa) 452 { 453 switch (regs->u_regs[UREG_I0]) { 454 case ERESTART_RESTARTBLOCK: 455 case ERESTARTNOHAND: 456 no_system_call_restart: 457 regs->u_regs[UREG_I0] = EINTR; 458 regs->tstate |= (TSTATE_ICARRY|TSTATE_XCARRY); 459 break; 460 case ERESTARTSYS: 461 if (!(sa->sa_flags & SA_RESTART)) 462 goto no_system_call_restart; 463 /* fallthrough */ 464 case ERESTARTNOINTR: 465 regs->u_regs[UREG_I0] = orig_i0; 466 regs->tpc -= 4; 467 regs->tnpc -= 4; 468 } 469 } 470 471 /* Note that 'init' is a special process: it doesn't get signals it doesn't 472 * want to handle. Thus you cannot kill init even with a SIGKILL even by 473 * mistake. 474 */ 475 static void do_signal(struct pt_regs *regs, unsigned long orig_i0) 476 { 477 struct ksignal ksig; 478 int restart_syscall; 479 bool has_handler; 480 481 /* It's a lot of work and synchronization to add a new ptrace 482 * register for GDB to save and restore in order to get 483 * orig_i0 correct for syscall restarts when debugging. 484 * 485 * Although it should be the case that most of the global 486 * registers are volatile across a system call, glibc already 487 * depends upon that fact that we preserve them. So we can't 488 * just use any global register to save away the orig_i0 value. 489 * 490 * In particular %g2, %g3, %g4, and %g5 are all assumed to be 491 * preserved across a system call trap by various pieces of 492 * code in glibc. 493 * 494 * %g7 is used as the "thread register". %g6 is not used in 495 * any fixed manner. %g6 is used as a scratch register and 496 * a compiler temporary, but it's value is never used across 497 * a system call. Therefore %g6 is usable for orig_i0 storage. 498 */ 499 if (pt_regs_is_syscall(regs) && 500 (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY))) 501 regs->u_regs[UREG_G6] = orig_i0; 502 503 #ifdef CONFIG_COMPAT 504 if (test_thread_flag(TIF_32BIT)) { 505 do_signal32(regs); 506 return; 507 } 508 #endif 509 510 has_handler = get_signal(&ksig); 511 512 restart_syscall = 0; 513 if (pt_regs_is_syscall(regs) && 514 (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY))) { 515 restart_syscall = 1; 516 orig_i0 = regs->u_regs[UREG_G6]; 517 } 518 519 if (has_handler) { 520 if (restart_syscall) 521 syscall_restart(orig_i0, regs, &ksig.ka.sa); 522 signal_setup_done(setup_rt_frame(&ksig, regs), &ksig, 0); 523 } else { 524 if (restart_syscall) { 525 switch (regs->u_regs[UREG_I0]) { 526 case ERESTARTNOHAND: 527 case ERESTARTSYS: 528 case ERESTARTNOINTR: 529 /* replay the system call when we are done */ 530 regs->u_regs[UREG_I0] = orig_i0; 531 regs->tpc -= 4; 532 regs->tnpc -= 4; 533 pt_regs_clear_syscall(regs); 534 case ERESTART_RESTARTBLOCK: 535 regs->u_regs[UREG_G1] = __NR_restart_syscall; 536 regs->tpc -= 4; 537 regs->tnpc -= 4; 538 pt_regs_clear_syscall(regs); 539 } 540 } 541 restore_saved_sigmask(); 542 } 543 } 544 545 void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, unsigned long thread_info_flags) 546 { 547 user_exit(); 548 if (thread_info_flags & _TIF_UPROBE) 549 uprobe_notify_resume(regs); 550 if (thread_info_flags & _TIF_SIGPENDING) 551 do_signal(regs, orig_i0); 552 if (thread_info_flags & _TIF_NOTIFY_RESUME) { 553 clear_thread_flag(TIF_NOTIFY_RESUME); 554 tracehook_notify_resume(regs); 555 } 556 user_enter(); 557 } 558 559