1 /* 2 * linux/arch/arm/kernel/signal.c 3 * 4 * Copyright (C) 1995-2002 Russell King 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 */ 10 #include <linux/errno.h> 11 #include <linux/signal.h> 12 #include <linux/ptrace.h> 13 #include <linux/personality.h> 14 #include <linux/freezer.h> 15 16 #include <asm/elf.h> 17 #include <asm/cacheflush.h> 18 #include <asm/ucontext.h> 19 #include <asm/uaccess.h> 20 #include <asm/unistd.h> 21 22 #include "ptrace.h" 23 #include "signal.h" 24 25 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) 26 27 /* 28 * For ARM syscalls, we encode the syscall number into the instruction. 29 */ 30 #define SWI_SYS_SIGRETURN (0xef000000|(__NR_sigreturn)) 31 #define SWI_SYS_RT_SIGRETURN (0xef000000|(__NR_rt_sigreturn)) 32 33 /* 34 * With EABI, the syscall number has to be loaded into r7. 35 */ 36 #define MOV_R7_NR_SIGRETURN (0xe3a07000 | (__NR_sigreturn - __NR_SYSCALL_BASE)) 37 #define MOV_R7_NR_RT_SIGRETURN (0xe3a07000 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE)) 38 39 /* 40 * For Thumb syscalls, we pass the syscall number via r7. We therefore 41 * need two 16-bit instructions. 42 */ 43 #define SWI_THUMB_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE)) 44 #define SWI_THUMB_RT_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE)) 45 46 const unsigned long sigreturn_codes[7] = { 47 MOV_R7_NR_SIGRETURN, SWI_SYS_SIGRETURN, SWI_THUMB_SIGRETURN, 48 MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN, 49 }; 50 51 static int do_signal(sigset_t *oldset, struct pt_regs * regs, int syscall); 52 53 /* 54 * atomically swap in the new signal mask, and wait for a signal. 55 */ 56 asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask, struct pt_regs *regs) 57 { 58 sigset_t saveset; 59 60 mask &= _BLOCKABLE; 61 spin_lock_irq(¤t->sighand->siglock); 62 saveset = current->blocked; 63 siginitset(¤t->blocked, mask); 64 recalc_sigpending(); 65 spin_unlock_irq(¤t->sighand->siglock); 66 regs->ARM_r0 = -EINTR; 67 68 while (1) { 69 current->state = TASK_INTERRUPTIBLE; 70 schedule(); 71 if (do_signal(&saveset, regs, 0)) 72 return regs->ARM_r0; 73 } 74 } 75 76 asmlinkage int 77 sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize, struct pt_regs *regs) 78 { 79 sigset_t saveset, newset; 80 81 /* XXX: Don't preclude handling different sized sigset_t's. */ 82 if (sigsetsize != sizeof(sigset_t)) 83 return -EINVAL; 84 85 if (copy_from_user(&newset, unewset, sizeof(newset))) 86 return -EFAULT; 87 sigdelsetmask(&newset, ~_BLOCKABLE); 88 89 spin_lock_irq(¤t->sighand->siglock); 90 saveset = current->blocked; 91 current->blocked = newset; 92 recalc_sigpending(); 93 spin_unlock_irq(¤t->sighand->siglock); 94 regs->ARM_r0 = -EINTR; 95 96 while (1) { 97 current->state = TASK_INTERRUPTIBLE; 98 schedule(); 99 if (do_signal(&saveset, regs, 0)) 100 return regs->ARM_r0; 101 } 102 } 103 104 asmlinkage int 105 sys_sigaction(int sig, const struct old_sigaction __user *act, 106 struct old_sigaction __user *oact) 107 { 108 struct k_sigaction new_ka, old_ka; 109 int ret; 110 111 if (act) { 112 old_sigset_t mask; 113 if (!access_ok(VERIFY_READ, act, sizeof(*act)) || 114 __get_user(new_ka.sa.sa_handler, &act->sa_handler) || 115 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer)) 116 return -EFAULT; 117 __get_user(new_ka.sa.sa_flags, &act->sa_flags); 118 __get_user(mask, &act->sa_mask); 119 siginitset(&new_ka.sa.sa_mask, mask); 120 } 121 122 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); 123 124 if (!ret && oact) { 125 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || 126 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || 127 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer)) 128 return -EFAULT; 129 __put_user(old_ka.sa.sa_flags, &oact->sa_flags); 130 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask); 131 } 132 133 return ret; 134 } 135 136 #ifdef CONFIG_CRUNCH 137 static int preserve_crunch_context(struct crunch_sigframe *frame) 138 { 139 char kbuf[sizeof(*frame) + 8]; 140 struct crunch_sigframe *kframe; 141 142 /* the crunch context must be 64 bit aligned */ 143 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7); 144 kframe->magic = CRUNCH_MAGIC; 145 kframe->size = CRUNCH_STORAGE_SIZE; 146 crunch_task_copy(current_thread_info(), &kframe->storage); 147 return __copy_to_user(frame, kframe, sizeof(*frame)); 148 } 149 150 static int restore_crunch_context(struct crunch_sigframe *frame) 151 { 152 char kbuf[sizeof(*frame) + 8]; 153 struct crunch_sigframe *kframe; 154 155 /* the crunch context must be 64 bit aligned */ 156 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7); 157 if (__copy_from_user(kframe, frame, sizeof(*frame))) 158 return -1; 159 if (kframe->magic != CRUNCH_MAGIC || 160 kframe->size != CRUNCH_STORAGE_SIZE) 161 return -1; 162 crunch_task_restore(current_thread_info(), &kframe->storage); 163 return 0; 164 } 165 #endif 166 167 #ifdef CONFIG_IWMMXT 168 169 static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame) 170 { 171 char kbuf[sizeof(*frame) + 8]; 172 struct iwmmxt_sigframe *kframe; 173 174 /* the iWMMXt context must be 64 bit aligned */ 175 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7); 176 kframe->magic = IWMMXT_MAGIC; 177 kframe->size = IWMMXT_STORAGE_SIZE; 178 iwmmxt_task_copy(current_thread_info(), &kframe->storage); 179 return __copy_to_user(frame, kframe, sizeof(*frame)); 180 } 181 182 static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame) 183 { 184 char kbuf[sizeof(*frame) + 8]; 185 struct iwmmxt_sigframe *kframe; 186 187 /* the iWMMXt context must be 64 bit aligned */ 188 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7); 189 if (__copy_from_user(kframe, frame, sizeof(*frame))) 190 return -1; 191 if (kframe->magic != IWMMXT_MAGIC || 192 kframe->size != IWMMXT_STORAGE_SIZE) 193 return -1; 194 iwmmxt_task_restore(current_thread_info(), &kframe->storage); 195 return 0; 196 } 197 198 #endif 199 200 /* 201 * Do a signal return; undo the signal stack. These are aligned to 64-bit. 202 */ 203 struct sigframe { 204 struct ucontext uc; 205 unsigned long retcode[2]; 206 }; 207 208 struct rt_sigframe { 209 struct siginfo info; 210 struct sigframe sig; 211 }; 212 213 static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf) 214 { 215 struct aux_sigframe __user *aux; 216 sigset_t set; 217 int err; 218 219 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set)); 220 if (err == 0) { 221 sigdelsetmask(&set, ~_BLOCKABLE); 222 spin_lock_irq(¤t->sighand->siglock); 223 current->blocked = set; 224 recalc_sigpending(); 225 spin_unlock_irq(¤t->sighand->siglock); 226 } 227 228 __get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err); 229 __get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err); 230 __get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err); 231 __get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err); 232 __get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err); 233 __get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err); 234 __get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err); 235 __get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err); 236 __get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err); 237 __get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err); 238 __get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err); 239 __get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err); 240 __get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err); 241 __get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err); 242 __get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err); 243 __get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err); 244 __get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err); 245 246 err |= !valid_user_regs(regs); 247 248 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace; 249 #ifdef CONFIG_CRUNCH 250 if (err == 0) 251 err |= restore_crunch_context(&aux->crunch); 252 #endif 253 #ifdef CONFIG_IWMMXT 254 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT)) 255 err |= restore_iwmmxt_context(&aux->iwmmxt); 256 #endif 257 #ifdef CONFIG_VFP 258 // if (err == 0) 259 // err |= vfp_restore_state(&sf->aux.vfp); 260 #endif 261 262 return err; 263 } 264 265 asmlinkage int sys_sigreturn(struct pt_regs *regs) 266 { 267 struct sigframe __user *frame; 268 269 /* Always make any pending restarted system calls return -EINTR */ 270 current_thread_info()->restart_block.fn = do_no_restart_syscall; 271 272 /* 273 * Since we stacked the signal on a 64-bit boundary, 274 * then 'sp' should be word aligned here. If it's 275 * not, then the user is trying to mess with us. 276 */ 277 if (regs->ARM_sp & 7) 278 goto badframe; 279 280 frame = (struct sigframe __user *)regs->ARM_sp; 281 282 if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) 283 goto badframe; 284 285 if (restore_sigframe(regs, frame)) 286 goto badframe; 287 288 /* Send SIGTRAP if we're single-stepping */ 289 if (current->ptrace & PT_SINGLESTEP) { 290 ptrace_cancel_bpt(current); 291 send_sig(SIGTRAP, current, 1); 292 } 293 294 return regs->ARM_r0; 295 296 badframe: 297 force_sig(SIGSEGV, current); 298 return 0; 299 } 300 301 asmlinkage int sys_rt_sigreturn(struct pt_regs *regs) 302 { 303 struct rt_sigframe __user *frame; 304 305 /* Always make any pending restarted system calls return -EINTR */ 306 current_thread_info()->restart_block.fn = do_no_restart_syscall; 307 308 /* 309 * Since we stacked the signal on a 64-bit boundary, 310 * then 'sp' should be word aligned here. If it's 311 * not, then the user is trying to mess with us. 312 */ 313 if (regs->ARM_sp & 7) 314 goto badframe; 315 316 frame = (struct rt_sigframe __user *)regs->ARM_sp; 317 318 if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) 319 goto badframe; 320 321 if (restore_sigframe(regs, &frame->sig)) 322 goto badframe; 323 324 if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT) 325 goto badframe; 326 327 /* Send SIGTRAP if we're single-stepping */ 328 if (current->ptrace & PT_SINGLESTEP) { 329 ptrace_cancel_bpt(current); 330 send_sig(SIGTRAP, current, 1); 331 } 332 333 return regs->ARM_r0; 334 335 badframe: 336 force_sig(SIGSEGV, current); 337 return 0; 338 } 339 340 static int 341 setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set) 342 { 343 struct aux_sigframe __user *aux; 344 int err = 0; 345 346 __put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err); 347 __put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err); 348 __put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err); 349 __put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err); 350 __put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err); 351 __put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err); 352 __put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err); 353 __put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err); 354 __put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err); 355 __put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err); 356 __put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err); 357 __put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err); 358 __put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err); 359 __put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err); 360 __put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err); 361 __put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err); 362 __put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err); 363 364 __put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err); 365 __put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err); 366 __put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err); 367 __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err); 368 369 err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set)); 370 371 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace; 372 #ifdef CONFIG_CRUNCH 373 if (err == 0) 374 err |= preserve_crunch_context(&aux->crunch); 375 #endif 376 #ifdef CONFIG_IWMMXT 377 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT)) 378 err |= preserve_iwmmxt_context(&aux->iwmmxt); 379 #endif 380 #ifdef CONFIG_VFP 381 // if (err == 0) 382 // err |= vfp_save_state(&sf->aux.vfp); 383 #endif 384 __put_user_error(0, &aux->end_magic, err); 385 386 return err; 387 } 388 389 static inline void __user * 390 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize) 391 { 392 unsigned long sp = regs->ARM_sp; 393 void __user *frame; 394 395 /* 396 * This is the X/Open sanctioned signal stack switching. 397 */ 398 if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp)) 399 sp = current->sas_ss_sp + current->sas_ss_size; 400 401 /* 402 * ATPCS B01 mandates 8-byte alignment 403 */ 404 frame = (void __user *)((sp - framesize) & ~7); 405 406 /* 407 * Check that we can actually write to the signal frame. 408 */ 409 if (!access_ok(VERIFY_WRITE, frame, framesize)) 410 frame = NULL; 411 412 return frame; 413 } 414 415 static int 416 setup_return(struct pt_regs *regs, struct k_sigaction *ka, 417 unsigned long __user *rc, void __user *frame, int usig) 418 { 419 unsigned long handler = (unsigned long)ka->sa.sa_handler; 420 unsigned long retcode; 421 int thumb = 0; 422 unsigned long cpsr = regs->ARM_cpsr & ~PSR_f; 423 424 /* 425 * Maybe we need to deliver a 32-bit signal to a 26-bit task. 426 */ 427 if (ka->sa.sa_flags & SA_THIRTYTWO) 428 cpsr = (cpsr & ~MODE_MASK) | USR_MODE; 429 430 #ifdef CONFIG_ARM_THUMB 431 if (elf_hwcap & HWCAP_THUMB) { 432 /* 433 * The LSB of the handler determines if we're going to 434 * be using THUMB or ARM mode for this signal handler. 435 */ 436 thumb = handler & 1; 437 438 if (thumb) 439 cpsr |= PSR_T_BIT; 440 else 441 cpsr &= ~PSR_T_BIT; 442 } 443 #endif 444 445 if (ka->sa.sa_flags & SA_RESTORER) { 446 retcode = (unsigned long)ka->sa.sa_restorer; 447 } else { 448 unsigned int idx = thumb << 1; 449 450 if (ka->sa.sa_flags & SA_SIGINFO) 451 idx += 3; 452 453 if (__put_user(sigreturn_codes[idx], rc) || 454 __put_user(sigreturn_codes[idx+1], rc+1)) 455 return 1; 456 457 if (cpsr & MODE32_BIT) { 458 /* 459 * 32-bit code can use the new high-page 460 * signal return code support. 461 */ 462 retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb; 463 } else { 464 /* 465 * Ensure that the instruction cache sees 466 * the return code written onto the stack. 467 */ 468 flush_icache_range((unsigned long)rc, 469 (unsigned long)(rc + 2)); 470 471 retcode = ((unsigned long)rc) + thumb; 472 } 473 } 474 475 regs->ARM_r0 = usig; 476 regs->ARM_sp = (unsigned long)frame; 477 regs->ARM_lr = retcode; 478 regs->ARM_pc = handler; 479 regs->ARM_cpsr = cpsr; 480 481 return 0; 482 } 483 484 static int 485 setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs) 486 { 487 struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame)); 488 int err = 0; 489 490 if (!frame) 491 return 1; 492 493 /* 494 * Set uc.uc_flags to a value which sc.trap_no would never have. 495 */ 496 __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err); 497 498 err |= setup_sigframe(frame, regs, set); 499 if (err == 0) 500 err = setup_return(regs, ka, frame->retcode, frame, usig); 501 502 return err; 503 } 504 505 static int 506 setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info, 507 sigset_t *set, struct pt_regs *regs) 508 { 509 struct rt_sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame)); 510 stack_t stack; 511 int err = 0; 512 513 if (!frame) 514 return 1; 515 516 err |= copy_siginfo_to_user(&frame->info, info); 517 518 __put_user_error(0, &frame->sig.uc.uc_flags, err); 519 __put_user_error(NULL, &frame->sig.uc.uc_link, err); 520 521 memset(&stack, 0, sizeof(stack)); 522 stack.ss_sp = (void __user *)current->sas_ss_sp; 523 stack.ss_flags = sas_ss_flags(regs->ARM_sp); 524 stack.ss_size = current->sas_ss_size; 525 err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack)); 526 527 err |= setup_sigframe(&frame->sig, regs, set); 528 if (err == 0) 529 err = setup_return(regs, ka, frame->sig.retcode, frame, usig); 530 531 if (err == 0) { 532 /* 533 * For realtime signals we must also set the second and third 534 * arguments for the signal handler. 535 * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06 536 */ 537 regs->ARM_r1 = (unsigned long)&frame->info; 538 regs->ARM_r2 = (unsigned long)&frame->sig.uc; 539 } 540 541 return err; 542 } 543 544 static inline void restart_syscall(struct pt_regs *regs) 545 { 546 regs->ARM_r0 = regs->ARM_ORIG_r0; 547 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4; 548 } 549 550 /* 551 * OK, we're invoking a handler 552 */ 553 static void 554 handle_signal(unsigned long sig, struct k_sigaction *ka, 555 siginfo_t *info, sigset_t *oldset, 556 struct pt_regs * regs, int syscall) 557 { 558 struct thread_info *thread = current_thread_info(); 559 struct task_struct *tsk = current; 560 int usig = sig; 561 int ret; 562 563 /* 564 * If we were from a system call, check for system call restarting... 565 */ 566 if (syscall) { 567 switch (regs->ARM_r0) { 568 case -ERESTART_RESTARTBLOCK: 569 case -ERESTARTNOHAND: 570 regs->ARM_r0 = -EINTR; 571 break; 572 case -ERESTARTSYS: 573 if (!(ka->sa.sa_flags & SA_RESTART)) { 574 regs->ARM_r0 = -EINTR; 575 break; 576 } 577 /* fallthrough */ 578 case -ERESTARTNOINTR: 579 restart_syscall(regs); 580 } 581 } 582 583 /* 584 * translate the signal 585 */ 586 if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap) 587 usig = thread->exec_domain->signal_invmap[usig]; 588 589 /* 590 * Set up the stack frame 591 */ 592 if (ka->sa.sa_flags & SA_SIGINFO) 593 ret = setup_rt_frame(usig, ka, info, oldset, regs); 594 else 595 ret = setup_frame(usig, ka, oldset, regs); 596 597 /* 598 * Check that the resulting registers are actually sane. 599 */ 600 ret |= !valid_user_regs(regs); 601 602 if (ret != 0) { 603 force_sigsegv(sig, tsk); 604 return; 605 } 606 607 /* 608 * Block the signal if we were successful. 609 */ 610 spin_lock_irq(&tsk->sighand->siglock); 611 sigorsets(&tsk->blocked, &tsk->blocked, 612 &ka->sa.sa_mask); 613 if (!(ka->sa.sa_flags & SA_NODEFER)) 614 sigaddset(&tsk->blocked, sig); 615 recalc_sigpending(); 616 spin_unlock_irq(&tsk->sighand->siglock); 617 618 } 619 620 /* 621 * Note that 'init' is a special process: it doesn't get signals it doesn't 622 * want to handle. Thus you cannot kill init even with a SIGKILL even by 623 * mistake. 624 * 625 * Note that we go through the signals twice: once to check the signals that 626 * the kernel can handle, and then we build all the user-level signal handling 627 * stack-frames in one go after that. 628 */ 629 static int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall) 630 { 631 struct k_sigaction ka; 632 siginfo_t info; 633 int signr; 634 635 /* 636 * We want the common case to go fast, which 637 * is why we may in certain cases get here from 638 * kernel mode. Just return without doing anything 639 * if so. 640 */ 641 if (!user_mode(regs)) 642 return 0; 643 644 if (try_to_freeze()) 645 goto no_signal; 646 647 if (current->ptrace & PT_SINGLESTEP) 648 ptrace_cancel_bpt(current); 649 650 signr = get_signal_to_deliver(&info, &ka, regs, NULL); 651 if (signr > 0) { 652 handle_signal(signr, &ka, &info, oldset, regs, syscall); 653 if (current->ptrace & PT_SINGLESTEP) 654 ptrace_set_bpt(current); 655 return 1; 656 } 657 658 no_signal: 659 /* 660 * No signal to deliver to the process - restart the syscall. 661 */ 662 if (syscall) { 663 if (regs->ARM_r0 == -ERESTART_RESTARTBLOCK) { 664 if (thumb_mode(regs)) { 665 regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE; 666 regs->ARM_pc -= 2; 667 } else { 668 #if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT) 669 regs->ARM_r7 = __NR_restart_syscall; 670 regs->ARM_pc -= 4; 671 #else 672 u32 __user *usp; 673 u32 swival = __NR_restart_syscall; 674 675 regs->ARM_sp -= 12; 676 usp = (u32 __user *)regs->ARM_sp; 677 678 /* 679 * Either we supports OABI only, or we have 680 * EABI with the OABI compat layer enabled. 681 * In the later case we don't know if user 682 * space is EABI or not, and if not we must 683 * not clobber r7. Always using the OABI 684 * syscall solves that issue and works for 685 * all those cases. 686 */ 687 swival = swival - __NR_SYSCALL_BASE + __NR_OABI_SYSCALL_BASE; 688 689 put_user(regs->ARM_pc, &usp[0]); 690 /* swi __NR_restart_syscall */ 691 put_user(0xef000000 | swival, &usp[1]); 692 /* ldr pc, [sp], #12 */ 693 put_user(0xe49df00c, &usp[2]); 694 695 flush_icache_range((unsigned long)usp, 696 (unsigned long)(usp + 3)); 697 698 regs->ARM_pc = regs->ARM_sp + 4; 699 #endif 700 } 701 } 702 if (regs->ARM_r0 == -ERESTARTNOHAND || 703 regs->ARM_r0 == -ERESTARTSYS || 704 regs->ARM_r0 == -ERESTARTNOINTR) { 705 restart_syscall(regs); 706 } 707 } 708 if (current->ptrace & PT_SINGLESTEP) 709 ptrace_set_bpt(current); 710 return 0; 711 } 712 713 asmlinkage void 714 do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall) 715 { 716 if (thread_flags & _TIF_SIGPENDING) 717 do_signal(¤t->blocked, regs, syscall); 718 } 719