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 <asm/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 flush_user_windows(); 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 struct rt_signal_frame { 238 struct sparc_stackf ss; 239 siginfo_t info; 240 struct pt_regs regs; 241 __siginfo_fpu_t __user *fpu_save; 242 stack_t stack; 243 sigset_t mask; 244 __siginfo_rwin_t *rwin_save; 245 }; 246 247 void do_rt_sigreturn(struct pt_regs *regs) 248 { 249 struct rt_signal_frame __user *sf; 250 unsigned long tpc, tnpc, tstate; 251 __siginfo_fpu_t __user *fpu_save; 252 __siginfo_rwin_t __user *rwin_save; 253 sigset_t set; 254 int err; 255 256 /* Always make any pending restarted system calls return -EINTR */ 257 current_thread_info()->restart_block.fn = do_no_restart_syscall; 258 259 synchronize_user_stack (); 260 sf = (struct rt_signal_frame __user *) 261 (regs->u_regs [UREG_FP] + STACK_BIAS); 262 263 /* 1. Make sure we are not getting garbage from the user */ 264 if (((unsigned long) sf) & 3) 265 goto segv; 266 267 err = get_user(tpc, &sf->regs.tpc); 268 err |= __get_user(tnpc, &sf->regs.tnpc); 269 if (test_thread_flag(TIF_32BIT)) { 270 tpc &= 0xffffffff; 271 tnpc &= 0xffffffff; 272 } 273 err |= ((tpc | tnpc) & 3); 274 275 /* 2. Restore the state */ 276 err |= __get_user(regs->y, &sf->regs.y); 277 err |= __get_user(tstate, &sf->regs.tstate); 278 err |= copy_from_user(regs->u_regs, sf->regs.u_regs, sizeof(regs->u_regs)); 279 280 /* User can only change condition codes and %asi in %tstate. */ 281 regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC); 282 regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC)); 283 284 err |= __get_user(fpu_save, &sf->fpu_save); 285 if (!err && fpu_save) 286 err |= restore_fpu_state(regs, fpu_save); 287 288 err |= __copy_from_user(&set, &sf->mask, sizeof(sigset_t)); 289 err |= restore_altstack(&sf->stack); 290 if (err) 291 goto segv; 292 293 err |= __get_user(rwin_save, &sf->rwin_save); 294 if (!err && rwin_save) { 295 if (restore_rwin_state(rwin_save)) 296 goto segv; 297 } 298 299 regs->tpc = tpc; 300 regs->tnpc = tnpc; 301 302 /* Prevent syscall restart. */ 303 pt_regs_clear_syscall(regs); 304 305 set_current_blocked(&set); 306 return; 307 segv: 308 force_sig(SIGSEGV, current); 309 } 310 311 /* Checks if the fp is valid */ 312 static int invalid_frame_pointer(void __user *fp) 313 { 314 if (((unsigned long) fp) & 15) 315 return 1; 316 return 0; 317 } 318 319 static inline void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, unsigned long framesize) 320 { 321 unsigned long sp = regs->u_regs[UREG_FP] + STACK_BIAS; 322 323 /* 324 * If we are on the alternate signal stack and would overflow it, don't. 325 * Return an always-bogus address instead so we will die with SIGSEGV. 326 */ 327 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize))) 328 return (void __user *) -1L; 329 330 /* This is the X/Open sanctioned signal stack switching. */ 331 sp = sigsp(sp, ksig) - framesize; 332 333 /* Always align the stack frame. This handles two cases. First, 334 * sigaltstack need not be mindful of platform specific stack 335 * alignment. Second, if we took this signal because the stack 336 * is not aligned properly, we'd like to take the signal cleanly 337 * and report that. 338 */ 339 sp &= ~15UL; 340 341 return (void __user *) sp; 342 } 343 344 static inline int 345 setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) 346 { 347 struct rt_signal_frame __user *sf; 348 int wsaved, err, sf_size; 349 void __user *tail; 350 351 /* 1. Make sure everything is clean */ 352 synchronize_user_stack(); 353 save_and_clear_fpu(); 354 355 wsaved = get_thread_wsaved(); 356 357 sf_size = sizeof(struct rt_signal_frame); 358 if (current_thread_info()->fpsaved[0] & FPRS_FEF) 359 sf_size += sizeof(__siginfo_fpu_t); 360 if (wsaved) 361 sf_size += sizeof(__siginfo_rwin_t); 362 sf = (struct rt_signal_frame __user *) 363 get_sigframe(ksig, regs, sf_size); 364 365 if (invalid_frame_pointer (sf)) { 366 do_exit(SIGILL); /* won't return, actually */ 367 return -EINVAL; 368 } 369 370 tail = (sf + 1); 371 372 /* 2. Save the current process state */ 373 err = copy_to_user(&sf->regs, regs, sizeof (*regs)); 374 375 if (current_thread_info()->fpsaved[0] & FPRS_FEF) { 376 __siginfo_fpu_t __user *fpu_save = tail; 377 tail += sizeof(__siginfo_fpu_t); 378 err |= save_fpu_state(regs, fpu_save); 379 err |= __put_user((u64)fpu_save, &sf->fpu_save); 380 } else { 381 err |= __put_user(0, &sf->fpu_save); 382 } 383 if (wsaved) { 384 __siginfo_rwin_t __user *rwin_save = tail; 385 tail += sizeof(__siginfo_rwin_t); 386 err |= save_rwin_state(wsaved, rwin_save); 387 err |= __put_user((u64)rwin_save, &sf->rwin_save); 388 set_thread_wsaved(0); 389 } else { 390 err |= __put_user(0, &sf->rwin_save); 391 } 392 393 /* Setup sigaltstack */ 394 err |= __save_altstack(&sf->stack, regs->u_regs[UREG_FP]); 395 396 err |= copy_to_user(&sf->mask, sigmask_to_save(), sizeof(sigset_t)); 397 398 if (!wsaved) { 399 err |= copy_in_user((u64 __user *)sf, 400 (u64 __user *)(regs->u_regs[UREG_FP] + 401 STACK_BIAS), 402 sizeof(struct reg_window)); 403 } else { 404 struct reg_window *rp; 405 406 rp = ¤t_thread_info()->reg_window[wsaved - 1]; 407 err |= copy_to_user(sf, rp, sizeof(struct reg_window)); 408 } 409 if (ksig->ka.sa.sa_flags & SA_SIGINFO) 410 err |= copy_siginfo_to_user(&sf->info, &ksig->info); 411 else { 412 err |= __put_user(ksig->sig, &sf->info.si_signo); 413 err |= __put_user(SI_NOINFO, &sf->info.si_code); 414 } 415 if (err) 416 return err; 417 418 /* 3. signal handler back-trampoline and parameters */ 419 regs->u_regs[UREG_FP] = ((unsigned long) sf) - STACK_BIAS; 420 regs->u_regs[UREG_I0] = ksig->sig; 421 regs->u_regs[UREG_I1] = (unsigned long) &sf->info; 422 423 /* The sigcontext is passed in this way because of how it 424 * is defined in GLIBC's /usr/include/bits/sigcontext.h 425 * for sparc64. It includes the 128 bytes of siginfo_t. 426 */ 427 regs->u_regs[UREG_I2] = (unsigned long) &sf->info; 428 429 /* 5. signal handler */ 430 regs->tpc = (unsigned long) ksig->ka.sa.sa_handler; 431 regs->tnpc = (regs->tpc + 4); 432 if (test_thread_flag(TIF_32BIT)) { 433 regs->tpc &= 0xffffffff; 434 regs->tnpc &= 0xffffffff; 435 } 436 /* 4. return to kernel instructions */ 437 regs->u_regs[UREG_I7] = (unsigned long)ksig->ka.ka_restorer; 438 return 0; 439 } 440 441 static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs, 442 struct sigaction *sa) 443 { 444 switch (regs->u_regs[UREG_I0]) { 445 case ERESTART_RESTARTBLOCK: 446 case ERESTARTNOHAND: 447 no_system_call_restart: 448 regs->u_regs[UREG_I0] = EINTR; 449 regs->tstate |= (TSTATE_ICARRY|TSTATE_XCARRY); 450 break; 451 case ERESTARTSYS: 452 if (!(sa->sa_flags & SA_RESTART)) 453 goto no_system_call_restart; 454 /* fallthrough */ 455 case ERESTARTNOINTR: 456 regs->u_regs[UREG_I0] = orig_i0; 457 regs->tpc -= 4; 458 regs->tnpc -= 4; 459 } 460 } 461 462 /* Note that 'init' is a special process: it doesn't get signals it doesn't 463 * want to handle. Thus you cannot kill init even with a SIGKILL even by 464 * mistake. 465 */ 466 static void do_signal(struct pt_regs *regs, unsigned long orig_i0) 467 { 468 struct ksignal ksig; 469 int restart_syscall; 470 bool has_handler; 471 472 /* It's a lot of work and synchronization to add a new ptrace 473 * register for GDB to save and restore in order to get 474 * orig_i0 correct for syscall restarts when debugging. 475 * 476 * Although it should be the case that most of the global 477 * registers are volatile across a system call, glibc already 478 * depends upon that fact that we preserve them. So we can't 479 * just use any global register to save away the orig_i0 value. 480 * 481 * In particular %g2, %g3, %g4, and %g5 are all assumed to be 482 * preserved across a system call trap by various pieces of 483 * code in glibc. 484 * 485 * %g7 is used as the "thread register". %g6 is not used in 486 * any fixed manner. %g6 is used as a scratch register and 487 * a compiler temporary, but it's value is never used across 488 * a system call. Therefore %g6 is usable for orig_i0 storage. 489 */ 490 if (pt_regs_is_syscall(regs) && 491 (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY))) 492 regs->u_regs[UREG_G6] = orig_i0; 493 494 #ifdef CONFIG_COMPAT 495 if (test_thread_flag(TIF_32BIT)) { 496 do_signal32(regs); 497 return; 498 } 499 #endif 500 501 has_handler = get_signal(&ksig); 502 503 restart_syscall = 0; 504 if (pt_regs_is_syscall(regs) && 505 (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY))) { 506 restart_syscall = 1; 507 orig_i0 = regs->u_regs[UREG_G6]; 508 } 509 510 if (has_handler) { 511 if (restart_syscall) 512 syscall_restart(orig_i0, regs, &ksig.ka.sa); 513 signal_setup_done(setup_rt_frame(&ksig, regs), &ksig, 0); 514 } else { 515 if (restart_syscall) { 516 switch (regs->u_regs[UREG_I0]) { 517 case ERESTARTNOHAND: 518 case ERESTARTSYS: 519 case ERESTARTNOINTR: 520 /* replay the system call when we are done */ 521 regs->u_regs[UREG_I0] = orig_i0; 522 regs->tpc -= 4; 523 regs->tnpc -= 4; 524 pt_regs_clear_syscall(regs); 525 case ERESTART_RESTARTBLOCK: 526 regs->u_regs[UREG_G1] = __NR_restart_syscall; 527 regs->tpc -= 4; 528 regs->tnpc -= 4; 529 pt_regs_clear_syscall(regs); 530 } 531 } 532 restore_saved_sigmask(); 533 } 534 } 535 536 void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, unsigned long thread_info_flags) 537 { 538 user_exit(); 539 if (thread_info_flags & _TIF_SIGPENDING) 540 do_signal(regs, orig_i0); 541 if (thread_info_flags & _TIF_NOTIFY_RESUME) { 542 clear_thread_flag(TIF_NOTIFY_RESUME); 543 tracehook_notify_resume(regs); 544 } 545 user_enter(); 546 } 547 548