1/* linux/arch/sparc/kernel/signal.c 2 * 3 * Copyright (C) 1991, 1992 Linus Torvalds 4 * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu) 5 * Copyright (C) 1996 Miguel de Icaza (miguel@nuclecu.unam.mx) 6 * Copyright (C) 1997 Eddie C. Dost (ecd@skynet.be) 7 */ 8 9#include <linux/sched.h> 10#include <linux/kernel.h> 11#include <linux/signal.h> 12#include <linux/errno.h> 13#include <linux/wait.h> 14#include <linux/ptrace.h> 15#include <linux/unistd.h> 16#include <linux/mm.h> 17#include <linux/tty.h> 18#include <linux/smp.h> 19#include <linux/binfmts.h> /* do_coredum */ 20#include <linux/bitops.h> 21#include <linux/tracehook.h> 22 23#include <asm/uaccess.h> 24#include <asm/ptrace.h> 25#include <asm/pgalloc.h> 26#include <asm/pgtable.h> 27#include <asm/cacheflush.h> /* flush_sig_insns */ 28#include <asm/switch_to.h> 29 30#include "sigutil.h" 31#include "kernel.h" 32 33extern void fpsave(unsigned long *fpregs, unsigned long *fsr, 34 void *fpqueue, unsigned long *fpqdepth); 35extern void fpload(unsigned long *fpregs, unsigned long *fsr); 36 37struct signal_frame { 38 struct sparc_stackf ss; 39 __siginfo32_t info; 40 __siginfo_fpu_t __user *fpu_save; 41 unsigned long insns[2] __attribute__ ((aligned (8))); 42 unsigned int extramask[_NSIG_WORDS - 1]; 43 unsigned int extra_size; /* Should be 0 */ 44 __siginfo_rwin_t __user *rwin_save; 45} __attribute__((aligned(8))); 46 47struct rt_signal_frame { 48 struct sparc_stackf ss; 49 siginfo_t info; 50 struct pt_regs regs; 51 sigset_t mask; 52 __siginfo_fpu_t __user *fpu_save; 53 unsigned int insns[2]; 54 stack_t stack; 55 unsigned int extra_size; /* Should be 0 */ 56 __siginfo_rwin_t __user *rwin_save; 57} __attribute__((aligned(8))); 58 59/* Align macros */ 60#define SF_ALIGNEDSZ (((sizeof(struct signal_frame) + 7) & (~7))) 61#define RT_ALIGNEDSZ (((sizeof(struct rt_signal_frame) + 7) & (~7))) 62 63asmlinkage void do_sigreturn(struct pt_regs *regs) 64{ 65 struct signal_frame __user *sf; 66 unsigned long up_psr, pc, npc; 67 sigset_t set; 68 __siginfo_fpu_t __user *fpu_save; 69 __siginfo_rwin_t __user *rwin_save; 70 int err; 71 72 /* Always make any pending restarted system calls return -EINTR */ 73 current->restart_block.fn = do_no_restart_syscall; 74 75 synchronize_user_stack(); 76 77 sf = (struct signal_frame __user *) regs->u_regs[UREG_FP]; 78 79 /* 1. Make sure we are not getting garbage from the user */ 80 if (!access_ok(VERIFY_READ, sf, sizeof(*sf))) 81 goto segv_and_exit; 82 83 if (((unsigned long) sf) & 3) 84 goto segv_and_exit; 85 86 err = __get_user(pc, &sf->info.si_regs.pc); 87 err |= __get_user(npc, &sf->info.si_regs.npc); 88 89 if ((pc | npc) & 3) 90 goto segv_and_exit; 91 92 /* 2. Restore the state */ 93 up_psr = regs->psr; 94 err |= __copy_from_user(regs, &sf->info.si_regs, sizeof(struct pt_regs)); 95 96 /* User can only change condition codes and FPU enabling in %psr. */ 97 regs->psr = (up_psr & ~(PSR_ICC | PSR_EF)) 98 | (regs->psr & (PSR_ICC | PSR_EF)); 99 100 /* Prevent syscall restart. */ 101 pt_regs_clear_syscall(regs); 102 103 err |= __get_user(fpu_save, &sf->fpu_save); 104 if (fpu_save) 105 err |= restore_fpu_state(regs, fpu_save); 106 err |= __get_user(rwin_save, &sf->rwin_save); 107 if (rwin_save) 108 err |= restore_rwin_state(rwin_save); 109 110 /* This is pretty much atomic, no amount locking would prevent 111 * the races which exist anyways. 112 */ 113 err |= __get_user(set.sig[0], &sf->info.si_mask); 114 err |= __copy_from_user(&set.sig[1], &sf->extramask, 115 (_NSIG_WORDS-1) * sizeof(unsigned int)); 116 117 if (err) 118 goto segv_and_exit; 119 120 set_current_blocked(&set); 121 return; 122 123segv_and_exit: 124 force_sig(SIGSEGV, current); 125} 126 127asmlinkage void do_rt_sigreturn(struct pt_regs *regs) 128{ 129 struct rt_signal_frame __user *sf; 130 unsigned int psr, pc, npc; 131 __siginfo_fpu_t __user *fpu_save; 132 __siginfo_rwin_t __user *rwin_save; 133 sigset_t set; 134 int err; 135 136 synchronize_user_stack(); 137 sf = (struct rt_signal_frame __user *) regs->u_regs[UREG_FP]; 138 if (!access_ok(VERIFY_READ, sf, sizeof(*sf)) || 139 (((unsigned long) sf) & 0x03)) 140 goto segv; 141 142 err = __get_user(pc, &sf->regs.pc); 143 err |= __get_user(npc, &sf->regs.npc); 144 err |= ((pc | npc) & 0x03); 145 146 err |= __get_user(regs->y, &sf->regs.y); 147 err |= __get_user(psr, &sf->regs.psr); 148 149 err |= __copy_from_user(®s->u_regs[UREG_G1], 150 &sf->regs.u_regs[UREG_G1], 15 * sizeof(u32)); 151 152 regs->psr = (regs->psr & ~PSR_ICC) | (psr & PSR_ICC); 153 154 /* Prevent syscall restart. */ 155 pt_regs_clear_syscall(regs); 156 157 err |= __get_user(fpu_save, &sf->fpu_save); 158 if (!err && fpu_save) 159 err |= restore_fpu_state(regs, fpu_save); 160 err |= __copy_from_user(&set, &sf->mask, sizeof(sigset_t)); 161 err |= restore_altstack(&sf->stack); 162 163 if (err) 164 goto segv; 165 166 regs->pc = pc; 167 regs->npc = npc; 168 169 err |= __get_user(rwin_save, &sf->rwin_save); 170 if (!err && rwin_save) { 171 if (restore_rwin_state(rwin_save)) 172 goto segv; 173 } 174 175 set_current_blocked(&set); 176 return; 177segv: 178 force_sig(SIGSEGV, current); 179} 180 181/* Checks if the fp is valid */ 182static inline int invalid_frame_pointer(void __user *fp, int fplen) 183{ 184 if ((((unsigned long) fp) & 7) || !__access_ok((unsigned long)fp, fplen)) 185 return 1; 186 187 return 0; 188} 189 190static inline void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, unsigned long framesize) 191{ 192 unsigned long sp = regs->u_regs[UREG_FP]; 193 194 /* 195 * If we are on the alternate signal stack and would overflow it, don't. 196 * Return an always-bogus address instead so we will die with SIGSEGV. 197 */ 198 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize))) 199 return (void __user *) -1L; 200 201 /* This is the X/Open sanctioned signal stack switching. */ 202 sp = sigsp(sp, ksig) - framesize; 203 204 /* Always align the stack frame. This handles two cases. First, 205 * sigaltstack need not be mindful of platform specific stack 206 * alignment. Second, if we took this signal because the stack 207 * is not aligned properly, we'd like to take the signal cleanly 208 * and report that. 209 */ 210 sp &= ~15UL; 211 212 return (void __user *) sp; 213} 214 215static int setup_frame(struct ksignal *ksig, struct pt_regs *regs, 216 sigset_t *oldset) 217{ 218 struct signal_frame __user *sf; 219 int sigframe_size, err, wsaved; 220 void __user *tail; 221 222 /* 1. Make sure everything is clean */ 223 synchronize_user_stack(); 224 225 wsaved = current_thread_info()->w_saved; 226 227 sigframe_size = sizeof(*sf); 228 if (used_math()) 229 sigframe_size += sizeof(__siginfo_fpu_t); 230 if (wsaved) 231 sigframe_size += sizeof(__siginfo_rwin_t); 232 233 sf = (struct signal_frame __user *) 234 get_sigframe(ksig, regs, sigframe_size); 235 236 if (invalid_frame_pointer(sf, sigframe_size)) { 237 do_exit(SIGILL); 238 return -EINVAL; 239 } 240 241 tail = sf + 1; 242 243 /* 2. Save the current process state */ 244 err = __copy_to_user(&sf->info.si_regs, regs, sizeof(struct pt_regs)); 245 246 err |= __put_user(0, &sf->extra_size); 247 248 if (used_math()) { 249 __siginfo_fpu_t __user *fp = tail; 250 tail += sizeof(*fp); 251 err |= save_fpu_state(regs, fp); 252 err |= __put_user(fp, &sf->fpu_save); 253 } else { 254 err |= __put_user(0, &sf->fpu_save); 255 } 256 if (wsaved) { 257 __siginfo_rwin_t __user *rwp = tail; 258 tail += sizeof(*rwp); 259 err |= save_rwin_state(wsaved, rwp); 260 err |= __put_user(rwp, &sf->rwin_save); 261 } else { 262 err |= __put_user(0, &sf->rwin_save); 263 } 264 265 err |= __put_user(oldset->sig[0], &sf->info.si_mask); 266 err |= __copy_to_user(sf->extramask, &oldset->sig[1], 267 (_NSIG_WORDS - 1) * sizeof(unsigned int)); 268 if (!wsaved) { 269 err |= __copy_to_user(sf, (char *) regs->u_regs[UREG_FP], 270 sizeof(struct reg_window32)); 271 } else { 272 struct reg_window32 *rp; 273 274 rp = ¤t_thread_info()->reg_window[wsaved - 1]; 275 err |= __copy_to_user(sf, rp, sizeof(struct reg_window32)); 276 } 277 if (err) 278 return err; 279 280 /* 3. signal handler back-trampoline and parameters */ 281 regs->u_regs[UREG_FP] = (unsigned long) sf; 282 regs->u_regs[UREG_I0] = ksig->sig; 283 regs->u_regs[UREG_I1] = (unsigned long) &sf->info; 284 regs->u_regs[UREG_I2] = (unsigned long) &sf->info; 285 286 /* 4. signal handler */ 287 regs->pc = (unsigned long) ksig->ka.sa.sa_handler; 288 regs->npc = (regs->pc + 4); 289 290 /* 5. return to kernel instructions */ 291 if (ksig->ka.ka_restorer) 292 regs->u_regs[UREG_I7] = (unsigned long)ksig->ka.ka_restorer; 293 else { 294 regs->u_regs[UREG_I7] = (unsigned long)(&(sf->insns[0]) - 2); 295 296 /* mov __NR_sigreturn, %g1 */ 297 err |= __put_user(0x821020d8, &sf->insns[0]); 298 299 /* t 0x10 */ 300 err |= __put_user(0x91d02010, &sf->insns[1]); 301 if (err) 302 return err; 303 304 /* Flush instruction space. */ 305 flush_sig_insns(current->mm, (unsigned long) &(sf->insns[0])); 306 } 307 return 0; 308} 309 310static int setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs, 311 sigset_t *oldset) 312{ 313 struct rt_signal_frame __user *sf; 314 int sigframe_size, wsaved; 315 void __user *tail; 316 unsigned int psr; 317 int err; 318 319 synchronize_user_stack(); 320 wsaved = current_thread_info()->w_saved; 321 sigframe_size = sizeof(*sf); 322 if (used_math()) 323 sigframe_size += sizeof(__siginfo_fpu_t); 324 if (wsaved) 325 sigframe_size += sizeof(__siginfo_rwin_t); 326 sf = (struct rt_signal_frame __user *) 327 get_sigframe(ksig, regs, sigframe_size); 328 if (invalid_frame_pointer(sf, sigframe_size)) { 329 do_exit(SIGILL); 330 return -EINVAL; 331 } 332 333 tail = sf + 1; 334 err = __put_user(regs->pc, &sf->regs.pc); 335 err |= __put_user(regs->npc, &sf->regs.npc); 336 err |= __put_user(regs->y, &sf->regs.y); 337 psr = regs->psr; 338 if (used_math()) 339 psr |= PSR_EF; 340 err |= __put_user(psr, &sf->regs.psr); 341 err |= __copy_to_user(&sf->regs.u_regs, regs->u_regs, sizeof(regs->u_regs)); 342 err |= __put_user(0, &sf->extra_size); 343 344 if (psr & PSR_EF) { 345 __siginfo_fpu_t __user *fp = tail; 346 tail += sizeof(*fp); 347 err |= save_fpu_state(regs, fp); 348 err |= __put_user(fp, &sf->fpu_save); 349 } else { 350 err |= __put_user(0, &sf->fpu_save); 351 } 352 if (wsaved) { 353 __siginfo_rwin_t __user *rwp = tail; 354 tail += sizeof(*rwp); 355 err |= save_rwin_state(wsaved, rwp); 356 err |= __put_user(rwp, &sf->rwin_save); 357 } else { 358 err |= __put_user(0, &sf->rwin_save); 359 } 360 err |= __copy_to_user(&sf->mask, &oldset->sig[0], sizeof(sigset_t)); 361 362 /* Setup sigaltstack */ 363 err |= __save_altstack(&sf->stack, regs->u_regs[UREG_FP]); 364 365 if (!wsaved) { 366 err |= __copy_to_user(sf, (char *) regs->u_regs[UREG_FP], 367 sizeof(struct reg_window32)); 368 } else { 369 struct reg_window32 *rp; 370 371 rp = ¤t_thread_info()->reg_window[wsaved - 1]; 372 err |= __copy_to_user(sf, rp, sizeof(struct reg_window32)); 373 } 374 375 err |= copy_siginfo_to_user(&sf->info, &ksig->info); 376 377 if (err) 378 return err; 379 380 regs->u_regs[UREG_FP] = (unsigned long) sf; 381 regs->u_regs[UREG_I0] = ksig->sig; 382 regs->u_regs[UREG_I1] = (unsigned long) &sf->info; 383 regs->u_regs[UREG_I2] = (unsigned long) &sf->regs; 384 385 regs->pc = (unsigned long) ksig->ka.sa.sa_handler; 386 regs->npc = (regs->pc + 4); 387 388 if (ksig->ka.ka_restorer) 389 regs->u_regs[UREG_I7] = (unsigned long)ksig->ka.ka_restorer; 390 else { 391 regs->u_regs[UREG_I7] = (unsigned long)(&(sf->insns[0]) - 2); 392 393 /* mov __NR_sigreturn, %g1 */ 394 err |= __put_user(0x821020d8, &sf->insns[0]); 395 396 /* t 0x10 */ 397 err |= __put_user(0x91d02010, &sf->insns[1]); 398 if (err) 399 return err; 400 401 /* Flush instruction space. */ 402 flush_sig_insns(current->mm, (unsigned long) &(sf->insns[0])); 403 } 404 return 0; 405} 406 407static inline void 408handle_signal(struct ksignal *ksig, struct pt_regs *regs) 409{ 410 sigset_t *oldset = sigmask_to_save(); 411 int err; 412 413 if (ksig->ka.sa.sa_flags & SA_SIGINFO) 414 err = setup_rt_frame(ksig, regs, oldset); 415 else 416 err = setup_frame(ksig, regs, oldset); 417 signal_setup_done(err, ksig, 0); 418} 419 420static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs, 421 struct sigaction *sa) 422{ 423 switch(regs->u_regs[UREG_I0]) { 424 case ERESTART_RESTARTBLOCK: 425 case ERESTARTNOHAND: 426 no_system_call_restart: 427 regs->u_regs[UREG_I0] = EINTR; 428 regs->psr |= PSR_C; 429 break; 430 case ERESTARTSYS: 431 if (!(sa->sa_flags & SA_RESTART)) 432 goto no_system_call_restart; 433 /* fallthrough */ 434 case ERESTARTNOINTR: 435 regs->u_regs[UREG_I0] = orig_i0; 436 regs->pc -= 4; 437 regs->npc -= 4; 438 } 439} 440 441/* Note that 'init' is a special process: it doesn't get signals it doesn't 442 * want to handle. Thus you cannot kill init even with a SIGKILL even by 443 * mistake. 444 */ 445static void do_signal(struct pt_regs *regs, unsigned long orig_i0) 446{ 447 struct ksignal ksig; 448 int restart_syscall; 449 bool has_handler; 450 451 /* It's a lot of work and synchronization to add a new ptrace 452 * register for GDB to save and restore in order to get 453 * orig_i0 correct for syscall restarts when debugging. 454 * 455 * Although it should be the case that most of the global 456 * registers are volatile across a system call, glibc already 457 * depends upon that fact that we preserve them. So we can't 458 * just use any global register to save away the orig_i0 value. 459 * 460 * In particular %g2, %g3, %g4, and %g5 are all assumed to be 461 * preserved across a system call trap by various pieces of 462 * code in glibc. 463 * 464 * %g7 is used as the "thread register". %g6 is not used in 465 * any fixed manner. %g6 is used as a scratch register and 466 * a compiler temporary, but it's value is never used across 467 * a system call. Therefore %g6 is usable for orig_i0 storage. 468 */ 469 if (pt_regs_is_syscall(regs) && (regs->psr & PSR_C)) 470 regs->u_regs[UREG_G6] = orig_i0; 471 472 has_handler = get_signal(&ksig); 473 474 /* If the debugger messes with the program counter, it clears 475 * the software "in syscall" bit, directing us to not perform 476 * a syscall restart. 477 */ 478 restart_syscall = 0; 479 if (pt_regs_is_syscall(regs) && (regs->psr & PSR_C)) { 480 restart_syscall = 1; 481 orig_i0 = regs->u_regs[UREG_G6]; 482 } 483 484 if (has_handler) { 485 if (restart_syscall) 486 syscall_restart(orig_i0, regs, &ksig.ka.sa); 487 handle_signal(&ksig, regs); 488 } else { 489 if (restart_syscall) { 490 switch (regs->u_regs[UREG_I0]) { 491 case ERESTARTNOHAND: 492 case ERESTARTSYS: 493 case ERESTARTNOINTR: 494 /* replay the system call when we are done */ 495 regs->u_regs[UREG_I0] = orig_i0; 496 regs->pc -= 4; 497 regs->npc -= 4; 498 pt_regs_clear_syscall(regs); 499 case ERESTART_RESTARTBLOCK: 500 regs->u_regs[UREG_G1] = __NR_restart_syscall; 501 regs->pc -= 4; 502 regs->npc -= 4; 503 pt_regs_clear_syscall(regs); 504 } 505 } 506 restore_saved_sigmask(); 507 } 508} 509 510void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, 511 unsigned long thread_info_flags) 512{ 513 if (thread_info_flags & _TIF_SIGPENDING) 514 do_signal(regs, orig_i0); 515 if (thread_info_flags & _TIF_NOTIFY_RESUME) { 516 clear_thread_flag(TIF_NOTIFY_RESUME); 517 tracehook_notify_resume(regs); 518 } 519} 520 521asmlinkage int do_sys_sigstack(struct sigstack __user *ssptr, 522 struct sigstack __user *ossptr, 523 unsigned long sp) 524{ 525 int ret = -EFAULT; 526 527 /* First see if old state is wanted. */ 528 if (ossptr) { 529 if (put_user(current->sas_ss_sp + current->sas_ss_size, 530 &ossptr->the_stack) || 531 __put_user(on_sig_stack(sp), &ossptr->cur_status)) 532 goto out; 533 } 534 535 /* Now see if we want to update the new state. */ 536 if (ssptr) { 537 char *ss_sp; 538 539 if (get_user(ss_sp, &ssptr->the_stack)) 540 goto out; 541 /* If the current stack was set with sigaltstack, don't 542 swap stacks while we are on it. */ 543 ret = -EPERM; 544 if (current->sas_ss_sp && on_sig_stack(sp)) 545 goto out; 546 547 /* Since we don't know the extent of the stack, and we don't 548 track onstack-ness, but rather calculate it, we must 549 presume a size. Ho hum this interface is lossy. */ 550 current->sas_ss_sp = (unsigned long)ss_sp - SIGSTKSZ; 551 current->sas_ss_size = SIGSTKSZ; 552 } 553 ret = 0; 554out: 555 return ret; 556} 557