1 /* 2 * linux/arch/arm/kernel/signal.c 3 * 4 * Copyright (C) 1995-2009 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/personality.h> 13 #include <linux/freezer.h> 14 #include <linux/uaccess.h> 15 #include <linux/tracehook.h> 16 17 #include <asm/elf.h> 18 #include <asm/cacheflush.h> 19 #include <asm/ucontext.h> 20 #include <asm/unistd.h> 21 #include <asm/vfp.h> 22 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)|(__NR_OABI_SYSCALL_BASE)) 31 #define SWI_SYS_RT_SIGRETURN (0xef000000|(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE)) 32 #define SWI_SYS_RESTART (0xef000000|__NR_restart_syscall|__NR_OABI_SYSCALL_BASE) 33 34 /* 35 * With EABI, the syscall number has to be loaded into r7. 36 */ 37 #define MOV_R7_NR_SIGRETURN (0xe3a07000 | (__NR_sigreturn - __NR_SYSCALL_BASE)) 38 #define MOV_R7_NR_RT_SIGRETURN (0xe3a07000 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE)) 39 40 /* 41 * For Thumb syscalls, we pass the syscall number via r7. We therefore 42 * need two 16-bit instructions. 43 */ 44 #define SWI_THUMB_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE)) 45 #define SWI_THUMB_RT_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE)) 46 47 const unsigned long sigreturn_codes[7] = { 48 MOV_R7_NR_SIGRETURN, SWI_SYS_SIGRETURN, SWI_THUMB_SIGRETURN, 49 MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN, 50 }; 51 52 /* 53 * Either we support OABI only, or we have EABI with the OABI 54 * compat layer enabled. In the later case we don't know if 55 * user space is EABI or not, and if not we must not clobber r7. 56 * Always using the OABI syscall solves that issue and works for 57 * all those cases. 58 */ 59 const unsigned long syscall_restart_code[2] = { 60 SWI_SYS_RESTART, /* swi __NR_restart_syscall */ 61 0xe49df004, /* ldr pc, [sp], #4 */ 62 }; 63 64 /* 65 * atomically swap in the new signal mask, and wait for a signal. 66 */ 67 asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask) 68 { 69 sigset_t blocked; 70 71 current->saved_sigmask = current->blocked; 72 73 mask &= _BLOCKABLE; 74 siginitset(&blocked, mask); 75 set_current_blocked(&blocked); 76 77 current->state = TASK_INTERRUPTIBLE; 78 schedule(); 79 set_restore_sigmask(); 80 return -ERESTARTNOHAND; 81 } 82 83 asmlinkage int 84 sys_sigaction(int sig, const struct old_sigaction __user *act, 85 struct old_sigaction __user *oact) 86 { 87 struct k_sigaction new_ka, old_ka; 88 int ret; 89 90 if (act) { 91 old_sigset_t mask; 92 if (!access_ok(VERIFY_READ, act, sizeof(*act)) || 93 __get_user(new_ka.sa.sa_handler, &act->sa_handler) || 94 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer)) 95 return -EFAULT; 96 __get_user(new_ka.sa.sa_flags, &act->sa_flags); 97 __get_user(mask, &act->sa_mask); 98 siginitset(&new_ka.sa.sa_mask, mask); 99 } 100 101 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); 102 103 if (!ret && oact) { 104 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || 105 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || 106 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer)) 107 return -EFAULT; 108 __put_user(old_ka.sa.sa_flags, &oact->sa_flags); 109 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask); 110 } 111 112 return ret; 113 } 114 115 #ifdef CONFIG_CRUNCH 116 static int preserve_crunch_context(struct crunch_sigframe __user *frame) 117 { 118 char kbuf[sizeof(*frame) + 8]; 119 struct crunch_sigframe *kframe; 120 121 /* the crunch context must be 64 bit aligned */ 122 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7); 123 kframe->magic = CRUNCH_MAGIC; 124 kframe->size = CRUNCH_STORAGE_SIZE; 125 crunch_task_copy(current_thread_info(), &kframe->storage); 126 return __copy_to_user(frame, kframe, sizeof(*frame)); 127 } 128 129 static int restore_crunch_context(struct crunch_sigframe __user *frame) 130 { 131 char kbuf[sizeof(*frame) + 8]; 132 struct crunch_sigframe *kframe; 133 134 /* the crunch context must be 64 bit aligned */ 135 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7); 136 if (__copy_from_user(kframe, frame, sizeof(*frame))) 137 return -1; 138 if (kframe->magic != CRUNCH_MAGIC || 139 kframe->size != CRUNCH_STORAGE_SIZE) 140 return -1; 141 crunch_task_restore(current_thread_info(), &kframe->storage); 142 return 0; 143 } 144 #endif 145 146 #ifdef CONFIG_IWMMXT 147 148 static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame) 149 { 150 char kbuf[sizeof(*frame) + 8]; 151 struct iwmmxt_sigframe *kframe; 152 153 /* the iWMMXt context must be 64 bit aligned */ 154 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7); 155 kframe->magic = IWMMXT_MAGIC; 156 kframe->size = IWMMXT_STORAGE_SIZE; 157 iwmmxt_task_copy(current_thread_info(), &kframe->storage); 158 return __copy_to_user(frame, kframe, sizeof(*frame)); 159 } 160 161 static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame) 162 { 163 char kbuf[sizeof(*frame) + 8]; 164 struct iwmmxt_sigframe *kframe; 165 166 /* the iWMMXt context must be 64 bit aligned */ 167 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7); 168 if (__copy_from_user(kframe, frame, sizeof(*frame))) 169 return -1; 170 if (kframe->magic != IWMMXT_MAGIC || 171 kframe->size != IWMMXT_STORAGE_SIZE) 172 return -1; 173 iwmmxt_task_restore(current_thread_info(), &kframe->storage); 174 return 0; 175 } 176 177 #endif 178 179 #ifdef CONFIG_VFP 180 181 static int preserve_vfp_context(struct vfp_sigframe __user *frame) 182 { 183 const unsigned long magic = VFP_MAGIC; 184 const unsigned long size = VFP_STORAGE_SIZE; 185 int err = 0; 186 187 __put_user_error(magic, &frame->magic, err); 188 __put_user_error(size, &frame->size, err); 189 190 if (err) 191 return -EFAULT; 192 193 return vfp_preserve_user_clear_hwstate(&frame->ufp, &frame->ufp_exc); 194 } 195 196 static int restore_vfp_context(struct vfp_sigframe __user *frame) 197 { 198 unsigned long magic; 199 unsigned long size; 200 int err = 0; 201 202 __get_user_error(magic, &frame->magic, err); 203 __get_user_error(size, &frame->size, err); 204 205 if (err) 206 return -EFAULT; 207 if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE) 208 return -EINVAL; 209 210 return vfp_restore_user_hwstate(&frame->ufp, &frame->ufp_exc); 211 } 212 213 #endif 214 215 /* 216 * Do a signal return; undo the signal stack. These are aligned to 64-bit. 217 */ 218 struct sigframe { 219 struct ucontext uc; 220 unsigned long retcode[2]; 221 }; 222 223 struct rt_sigframe { 224 struct siginfo info; 225 struct sigframe sig; 226 }; 227 228 static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf) 229 { 230 struct aux_sigframe __user *aux; 231 sigset_t set; 232 int err; 233 234 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set)); 235 if (err == 0) { 236 sigdelsetmask(&set, ~_BLOCKABLE); 237 set_current_blocked(&set); 238 } 239 240 __get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err); 241 __get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err); 242 __get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err); 243 __get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err); 244 __get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err); 245 __get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err); 246 __get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err); 247 __get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err); 248 __get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err); 249 __get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err); 250 __get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err); 251 __get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err); 252 __get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err); 253 __get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err); 254 __get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err); 255 __get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err); 256 __get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err); 257 258 err |= !valid_user_regs(regs); 259 260 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace; 261 #ifdef CONFIG_CRUNCH 262 if (err == 0) 263 err |= restore_crunch_context(&aux->crunch); 264 #endif 265 #ifdef CONFIG_IWMMXT 266 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT)) 267 err |= restore_iwmmxt_context(&aux->iwmmxt); 268 #endif 269 #ifdef CONFIG_VFP 270 if (err == 0) 271 err |= restore_vfp_context(&aux->vfp); 272 #endif 273 274 return err; 275 } 276 277 asmlinkage int sys_sigreturn(struct pt_regs *regs) 278 { 279 struct sigframe __user *frame; 280 281 /* Always make any pending restarted system calls return -EINTR */ 282 current_thread_info()->restart_block.fn = do_no_restart_syscall; 283 284 /* 285 * Since we stacked the signal on a 64-bit boundary, 286 * then 'sp' should be word aligned here. If it's 287 * not, then the user is trying to mess with us. 288 */ 289 if (regs->ARM_sp & 7) 290 goto badframe; 291 292 frame = (struct sigframe __user *)regs->ARM_sp; 293 294 if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) 295 goto badframe; 296 297 if (restore_sigframe(regs, frame)) 298 goto badframe; 299 300 return regs->ARM_r0; 301 302 badframe: 303 force_sig(SIGSEGV, current); 304 return 0; 305 } 306 307 asmlinkage int sys_rt_sigreturn(struct pt_regs *regs) 308 { 309 struct rt_sigframe __user *frame; 310 311 /* Always make any pending restarted system calls return -EINTR */ 312 current_thread_info()->restart_block.fn = do_no_restart_syscall; 313 314 /* 315 * Since we stacked the signal on a 64-bit boundary, 316 * then 'sp' should be word aligned here. If it's 317 * not, then the user is trying to mess with us. 318 */ 319 if (regs->ARM_sp & 7) 320 goto badframe; 321 322 frame = (struct rt_sigframe __user *)regs->ARM_sp; 323 324 if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) 325 goto badframe; 326 327 if (restore_sigframe(regs, &frame->sig)) 328 goto badframe; 329 330 if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT) 331 goto badframe; 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 |= preserve_vfp_context(&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 | PSR_E_BIT); 423 424 cpsr |= PSR_ENDSTATE; 425 426 /* 427 * Maybe we need to deliver a 32-bit signal to a 26-bit task. 428 */ 429 if (ka->sa.sa_flags & SA_THIRTYTWO) 430 cpsr = (cpsr & ~MODE_MASK) | USR_MODE; 431 432 #ifdef CONFIG_ARM_THUMB 433 if (elf_hwcap & HWCAP_THUMB) { 434 /* 435 * The LSB of the handler determines if we're going to 436 * be using THUMB or ARM mode for this signal handler. 437 */ 438 thumb = handler & 1; 439 440 if (thumb) { 441 cpsr |= PSR_T_BIT; 442 #if __LINUX_ARM_ARCH__ >= 7 443 /* clear the If-Then Thumb-2 execution state */ 444 cpsr &= ~PSR_IT_MASK; 445 #endif 446 } else 447 cpsr &= ~PSR_T_BIT; 448 } 449 #endif 450 451 if (ka->sa.sa_flags & SA_RESTORER) { 452 retcode = (unsigned long)ka->sa.sa_restorer; 453 } else { 454 unsigned int idx = thumb << 1; 455 456 if (ka->sa.sa_flags & SA_SIGINFO) 457 idx += 3; 458 459 if (__put_user(sigreturn_codes[idx], rc) || 460 __put_user(sigreturn_codes[idx+1], rc+1)) 461 return 1; 462 463 if (cpsr & MODE32_BIT) { 464 /* 465 * 32-bit code can use the new high-page 466 * signal return code support. 467 */ 468 retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb; 469 } else { 470 /* 471 * Ensure that the instruction cache sees 472 * the return code written onto the stack. 473 */ 474 flush_icache_range((unsigned long)rc, 475 (unsigned long)(rc + 2)); 476 477 retcode = ((unsigned long)rc) + thumb; 478 } 479 } 480 481 regs->ARM_r0 = usig; 482 regs->ARM_sp = (unsigned long)frame; 483 regs->ARM_lr = retcode; 484 regs->ARM_pc = handler; 485 regs->ARM_cpsr = cpsr; 486 487 return 0; 488 } 489 490 static int 491 setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs) 492 { 493 struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame)); 494 int err = 0; 495 496 if (!frame) 497 return 1; 498 499 /* 500 * Set uc.uc_flags to a value which sc.trap_no would never have. 501 */ 502 __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err); 503 504 err |= setup_sigframe(frame, regs, set); 505 if (err == 0) 506 err = setup_return(regs, ka, frame->retcode, frame, usig); 507 508 return err; 509 } 510 511 static int 512 setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info, 513 sigset_t *set, struct pt_regs *regs) 514 { 515 struct rt_sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame)); 516 stack_t stack; 517 int err = 0; 518 519 if (!frame) 520 return 1; 521 522 err |= copy_siginfo_to_user(&frame->info, info); 523 524 __put_user_error(0, &frame->sig.uc.uc_flags, err); 525 __put_user_error(NULL, &frame->sig.uc.uc_link, err); 526 527 memset(&stack, 0, sizeof(stack)); 528 stack.ss_sp = (void __user *)current->sas_ss_sp; 529 stack.ss_flags = sas_ss_flags(regs->ARM_sp); 530 stack.ss_size = current->sas_ss_size; 531 err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack)); 532 533 err |= setup_sigframe(&frame->sig, regs, set); 534 if (err == 0) 535 err = setup_return(regs, ka, frame->sig.retcode, frame, usig); 536 537 if (err == 0) { 538 /* 539 * For realtime signals we must also set the second and third 540 * arguments for the signal handler. 541 * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06 542 */ 543 regs->ARM_r1 = (unsigned long)&frame->info; 544 regs->ARM_r2 = (unsigned long)&frame->sig.uc; 545 } 546 547 return err; 548 } 549 550 /* 551 * OK, we're invoking a handler 552 */ 553 static int 554 handle_signal(unsigned long sig, struct k_sigaction *ka, 555 siginfo_t *info, sigset_t *oldset, 556 struct pt_regs * regs) 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 * translate the signal 565 */ 566 if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap) 567 usig = thread->exec_domain->signal_invmap[usig]; 568 569 /* 570 * Set up the stack frame 571 */ 572 if (ka->sa.sa_flags & SA_SIGINFO) 573 ret = setup_rt_frame(usig, ka, info, oldset, regs); 574 else 575 ret = setup_frame(usig, ka, oldset, regs); 576 577 /* 578 * Check that the resulting registers are actually sane. 579 */ 580 ret |= !valid_user_regs(regs); 581 582 if (ret != 0) { 583 force_sigsegv(sig, tsk); 584 return ret; 585 } 586 587 /* 588 * Block the signal if we were successful. 589 */ 590 block_sigmask(ka, sig); 591 592 return 0; 593 } 594 595 /* 596 * Note that 'init' is a special process: it doesn't get signals it doesn't 597 * want to handle. Thus you cannot kill init even with a SIGKILL even by 598 * mistake. 599 * 600 * Note that we go through the signals twice: once to check the signals that 601 * the kernel can handle, and then we build all the user-level signal handling 602 * stack-frames in one go after that. 603 */ 604 static void do_signal(struct pt_regs *regs, int syscall) 605 { 606 unsigned int retval = 0, continue_addr = 0, restart_addr = 0; 607 struct k_sigaction ka; 608 siginfo_t info; 609 int signr; 610 611 /* 612 * We want the common case to go fast, which 613 * is why we may in certain cases get here from 614 * kernel mode. Just return without doing anything 615 * if so. 616 */ 617 if (!user_mode(regs)) 618 return; 619 620 /* 621 * If we were from a system call, check for system call restarting... 622 */ 623 if (syscall) { 624 continue_addr = regs->ARM_pc; 625 restart_addr = continue_addr - (thumb_mode(regs) ? 2 : 4); 626 retval = regs->ARM_r0; 627 628 /* 629 * Prepare for system call restart. We do this here so that a 630 * debugger will see the already changed PSW. 631 */ 632 switch (retval) { 633 case -ERESTARTNOHAND: 634 case -ERESTARTSYS: 635 case -ERESTARTNOINTR: 636 regs->ARM_r0 = regs->ARM_ORIG_r0; 637 regs->ARM_pc = restart_addr; 638 break; 639 case -ERESTART_RESTARTBLOCK: 640 regs->ARM_r0 = -EINTR; 641 break; 642 } 643 } 644 645 if (try_to_freeze()) 646 goto no_signal; 647 648 /* 649 * Get the signal to deliver. When running under ptrace, at this 650 * point the debugger may change all our registers ... 651 */ 652 signr = get_signal_to_deliver(&info, &ka, regs, NULL); 653 if (signr > 0) { 654 sigset_t *oldset; 655 656 /* 657 * Depending on the signal settings we may need to revert the 658 * decision to restart the system call. But skip this if a 659 * debugger has chosen to restart at a different PC. 660 */ 661 if (regs->ARM_pc == restart_addr) { 662 if (retval == -ERESTARTNOHAND 663 || (retval == -ERESTARTSYS 664 && !(ka.sa.sa_flags & SA_RESTART))) { 665 regs->ARM_r0 = -EINTR; 666 regs->ARM_pc = continue_addr; 667 } 668 } 669 670 if (test_thread_flag(TIF_RESTORE_SIGMASK)) 671 oldset = ¤t->saved_sigmask; 672 else 673 oldset = ¤t->blocked; 674 if (handle_signal(signr, &ka, &info, oldset, regs) == 0) { 675 /* 676 * A signal was successfully delivered; the saved 677 * sigmask will have been stored in the signal frame, 678 * and will be restored by sigreturn, so we can simply 679 * clear the TIF_RESTORE_SIGMASK flag. 680 */ 681 if (test_thread_flag(TIF_RESTORE_SIGMASK)) 682 clear_thread_flag(TIF_RESTORE_SIGMASK); 683 } 684 return; 685 } 686 687 no_signal: 688 if (syscall) { 689 /* 690 * Handle restarting a different system call. As above, 691 * if a debugger has chosen to restart at a different PC, 692 * ignore the restart. 693 */ 694 if (retval == -ERESTART_RESTARTBLOCK 695 && regs->ARM_pc == continue_addr) { 696 if (thumb_mode(regs)) { 697 regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE; 698 regs->ARM_pc -= 2; 699 } else { 700 #if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT) 701 regs->ARM_r7 = __NR_restart_syscall; 702 regs->ARM_pc -= 4; 703 #else 704 u32 __user *usp; 705 706 regs->ARM_sp -= 4; 707 usp = (u32 __user *)regs->ARM_sp; 708 709 if (put_user(regs->ARM_pc, usp) == 0) { 710 regs->ARM_pc = KERN_RESTART_CODE; 711 } else { 712 regs->ARM_sp += 4; 713 force_sigsegv(0, current); 714 } 715 #endif 716 } 717 } 718 719 /* If there's no signal to deliver, we just put the saved sigmask 720 * back. 721 */ 722 if (test_thread_flag(TIF_RESTORE_SIGMASK)) { 723 clear_thread_flag(TIF_RESTORE_SIGMASK); 724 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); 725 } 726 } 727 } 728 729 asmlinkage void 730 do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall) 731 { 732 if (thread_flags & _TIF_SIGPENDING) 733 do_signal(regs, syscall); 734 735 if (thread_flags & _TIF_NOTIFY_RESUME) { 736 clear_thread_flag(TIF_NOTIFY_RESUME); 737 tracehook_notify_resume(regs); 738 if (current->replacement_session_keyring) 739 key_replace_session_keyring(); 740 } 741 } 742