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 struct thread_info *thread = current_thread_info(); 184 struct vfp_hard_struct *h = &thread->vfpstate.hard; 185 const unsigned long magic = VFP_MAGIC; 186 const unsigned long size = VFP_STORAGE_SIZE; 187 int err = 0; 188 189 vfp_sync_hwstate(thread); 190 __put_user_error(magic, &frame->magic, err); 191 __put_user_error(size, &frame->size, err); 192 193 /* 194 * Copy the floating point registers. There can be unused 195 * registers see asm/hwcap.h for details. 196 */ 197 err |= __copy_to_user(&frame->ufp.fpregs, &h->fpregs, 198 sizeof(h->fpregs)); 199 /* 200 * Copy the status and control register. 201 */ 202 __put_user_error(h->fpscr, &frame->ufp.fpscr, err); 203 204 /* 205 * Copy the exception registers. 206 */ 207 __put_user_error(h->fpexc, &frame->ufp_exc.fpexc, err); 208 __put_user_error(h->fpinst, &frame->ufp_exc.fpinst, err); 209 __put_user_error(h->fpinst2, &frame->ufp_exc.fpinst2, err); 210 211 return err ? -EFAULT : 0; 212 } 213 214 static int restore_vfp_context(struct vfp_sigframe __user *frame) 215 { 216 struct thread_info *thread = current_thread_info(); 217 struct vfp_hard_struct *h = &thread->vfpstate.hard; 218 unsigned long magic; 219 unsigned long size; 220 unsigned long fpexc; 221 int err = 0; 222 223 __get_user_error(magic, &frame->magic, err); 224 __get_user_error(size, &frame->size, err); 225 226 if (err) 227 return -EFAULT; 228 if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE) 229 return -EINVAL; 230 231 vfp_flush_hwstate(thread); 232 233 /* 234 * Copy the floating point registers. There can be unused 235 * registers see asm/hwcap.h for details. 236 */ 237 err |= __copy_from_user(&h->fpregs, &frame->ufp.fpregs, 238 sizeof(h->fpregs)); 239 /* 240 * Copy the status and control register. 241 */ 242 __get_user_error(h->fpscr, &frame->ufp.fpscr, err); 243 244 /* 245 * Sanitise and restore the exception registers. 246 */ 247 __get_user_error(fpexc, &frame->ufp_exc.fpexc, err); 248 /* Ensure the VFP is enabled. */ 249 fpexc |= FPEXC_EN; 250 /* Ensure FPINST2 is invalid and the exception flag is cleared. */ 251 fpexc &= ~(FPEXC_EX | FPEXC_FP2V); 252 h->fpexc = fpexc; 253 254 __get_user_error(h->fpinst, &frame->ufp_exc.fpinst, err); 255 __get_user_error(h->fpinst2, &frame->ufp_exc.fpinst2, err); 256 257 return err ? -EFAULT : 0; 258 } 259 260 #endif 261 262 /* 263 * Do a signal return; undo the signal stack. These are aligned to 64-bit. 264 */ 265 struct sigframe { 266 struct ucontext uc; 267 unsigned long retcode[2]; 268 }; 269 270 struct rt_sigframe { 271 struct siginfo info; 272 struct sigframe sig; 273 }; 274 275 static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf) 276 { 277 struct aux_sigframe __user *aux; 278 sigset_t set; 279 int err; 280 281 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set)); 282 if (err == 0) { 283 sigdelsetmask(&set, ~_BLOCKABLE); 284 set_current_blocked(&set); 285 } 286 287 __get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err); 288 __get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err); 289 __get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err); 290 __get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err); 291 __get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err); 292 __get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err); 293 __get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err); 294 __get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err); 295 __get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err); 296 __get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err); 297 __get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err); 298 __get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err); 299 __get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err); 300 __get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err); 301 __get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err); 302 __get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err); 303 __get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err); 304 305 err |= !valid_user_regs(regs); 306 307 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace; 308 #ifdef CONFIG_CRUNCH 309 if (err == 0) 310 err |= restore_crunch_context(&aux->crunch); 311 #endif 312 #ifdef CONFIG_IWMMXT 313 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT)) 314 err |= restore_iwmmxt_context(&aux->iwmmxt); 315 #endif 316 #ifdef CONFIG_VFP 317 if (err == 0) 318 err |= restore_vfp_context(&aux->vfp); 319 #endif 320 321 return err; 322 } 323 324 asmlinkage int sys_sigreturn(struct pt_regs *regs) 325 { 326 struct sigframe __user *frame; 327 328 /* Always make any pending restarted system calls return -EINTR */ 329 current_thread_info()->restart_block.fn = do_no_restart_syscall; 330 331 /* 332 * Since we stacked the signal on a 64-bit boundary, 333 * then 'sp' should be word aligned here. If it's 334 * not, then the user is trying to mess with us. 335 */ 336 if (regs->ARM_sp & 7) 337 goto badframe; 338 339 frame = (struct sigframe __user *)regs->ARM_sp; 340 341 if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) 342 goto badframe; 343 344 if (restore_sigframe(regs, frame)) 345 goto badframe; 346 347 return regs->ARM_r0; 348 349 badframe: 350 force_sig(SIGSEGV, current); 351 return 0; 352 } 353 354 asmlinkage int sys_rt_sigreturn(struct pt_regs *regs) 355 { 356 struct rt_sigframe __user *frame; 357 358 /* Always make any pending restarted system calls return -EINTR */ 359 current_thread_info()->restart_block.fn = do_no_restart_syscall; 360 361 /* 362 * Since we stacked the signal on a 64-bit boundary, 363 * then 'sp' should be word aligned here. If it's 364 * not, then the user is trying to mess with us. 365 */ 366 if (regs->ARM_sp & 7) 367 goto badframe; 368 369 frame = (struct rt_sigframe __user *)regs->ARM_sp; 370 371 if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) 372 goto badframe; 373 374 if (restore_sigframe(regs, &frame->sig)) 375 goto badframe; 376 377 if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT) 378 goto badframe; 379 380 return regs->ARM_r0; 381 382 badframe: 383 force_sig(SIGSEGV, current); 384 return 0; 385 } 386 387 static int 388 setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set) 389 { 390 struct aux_sigframe __user *aux; 391 int err = 0; 392 393 __put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err); 394 __put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err); 395 __put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err); 396 __put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err); 397 __put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err); 398 __put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err); 399 __put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err); 400 __put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err); 401 __put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err); 402 __put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err); 403 __put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err); 404 __put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err); 405 __put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err); 406 __put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err); 407 __put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err); 408 __put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err); 409 __put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err); 410 411 __put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err); 412 __put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err); 413 __put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err); 414 __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err); 415 416 err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set)); 417 418 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace; 419 #ifdef CONFIG_CRUNCH 420 if (err == 0) 421 err |= preserve_crunch_context(&aux->crunch); 422 #endif 423 #ifdef CONFIG_IWMMXT 424 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT)) 425 err |= preserve_iwmmxt_context(&aux->iwmmxt); 426 #endif 427 #ifdef CONFIG_VFP 428 if (err == 0) 429 err |= preserve_vfp_context(&aux->vfp); 430 #endif 431 __put_user_error(0, &aux->end_magic, err); 432 433 return err; 434 } 435 436 static inline void __user * 437 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize) 438 { 439 unsigned long sp = regs->ARM_sp; 440 void __user *frame; 441 442 /* 443 * This is the X/Open sanctioned signal stack switching. 444 */ 445 if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp)) 446 sp = current->sas_ss_sp + current->sas_ss_size; 447 448 /* 449 * ATPCS B01 mandates 8-byte alignment 450 */ 451 frame = (void __user *)((sp - framesize) & ~7); 452 453 /* 454 * Check that we can actually write to the signal frame. 455 */ 456 if (!access_ok(VERIFY_WRITE, frame, framesize)) 457 frame = NULL; 458 459 return frame; 460 } 461 462 static int 463 setup_return(struct pt_regs *regs, struct k_sigaction *ka, 464 unsigned long __user *rc, void __user *frame, int usig) 465 { 466 unsigned long handler = (unsigned long)ka->sa.sa_handler; 467 unsigned long retcode; 468 int thumb = 0; 469 unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT); 470 471 cpsr |= PSR_ENDSTATE; 472 473 /* 474 * Maybe we need to deliver a 32-bit signal to a 26-bit task. 475 */ 476 if (ka->sa.sa_flags & SA_THIRTYTWO) 477 cpsr = (cpsr & ~MODE_MASK) | USR_MODE; 478 479 #ifdef CONFIG_ARM_THUMB 480 if (elf_hwcap & HWCAP_THUMB) { 481 /* 482 * The LSB of the handler determines if we're going to 483 * be using THUMB or ARM mode for this signal handler. 484 */ 485 thumb = handler & 1; 486 487 if (thumb) { 488 cpsr |= PSR_T_BIT; 489 #if __LINUX_ARM_ARCH__ >= 7 490 /* clear the If-Then Thumb-2 execution state */ 491 cpsr &= ~PSR_IT_MASK; 492 #endif 493 } else 494 cpsr &= ~PSR_T_BIT; 495 } 496 #endif 497 498 if (ka->sa.sa_flags & SA_RESTORER) { 499 retcode = (unsigned long)ka->sa.sa_restorer; 500 } else { 501 unsigned int idx = thumb << 1; 502 503 if (ka->sa.sa_flags & SA_SIGINFO) 504 idx += 3; 505 506 if (__put_user(sigreturn_codes[idx], rc) || 507 __put_user(sigreturn_codes[idx+1], rc+1)) 508 return 1; 509 510 if (cpsr & MODE32_BIT) { 511 /* 512 * 32-bit code can use the new high-page 513 * signal return code support. 514 */ 515 retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb; 516 } else { 517 /* 518 * Ensure that the instruction cache sees 519 * the return code written onto the stack. 520 */ 521 flush_icache_range((unsigned long)rc, 522 (unsigned long)(rc + 2)); 523 524 retcode = ((unsigned long)rc) + thumb; 525 } 526 } 527 528 regs->ARM_r0 = usig; 529 regs->ARM_sp = (unsigned long)frame; 530 regs->ARM_lr = retcode; 531 regs->ARM_pc = handler; 532 regs->ARM_cpsr = cpsr; 533 534 return 0; 535 } 536 537 static int 538 setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs) 539 { 540 struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame)); 541 int err = 0; 542 543 if (!frame) 544 return 1; 545 546 /* 547 * Set uc.uc_flags to a value which sc.trap_no would never have. 548 */ 549 __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err); 550 551 err |= setup_sigframe(frame, regs, set); 552 if (err == 0) 553 err = setup_return(regs, ka, frame->retcode, frame, usig); 554 555 return err; 556 } 557 558 static int 559 setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info, 560 sigset_t *set, struct pt_regs *regs) 561 { 562 struct rt_sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame)); 563 stack_t stack; 564 int err = 0; 565 566 if (!frame) 567 return 1; 568 569 err |= copy_siginfo_to_user(&frame->info, info); 570 571 __put_user_error(0, &frame->sig.uc.uc_flags, err); 572 __put_user_error(NULL, &frame->sig.uc.uc_link, err); 573 574 memset(&stack, 0, sizeof(stack)); 575 stack.ss_sp = (void __user *)current->sas_ss_sp; 576 stack.ss_flags = sas_ss_flags(regs->ARM_sp); 577 stack.ss_size = current->sas_ss_size; 578 err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack)); 579 580 err |= setup_sigframe(&frame->sig, regs, set); 581 if (err == 0) 582 err = setup_return(regs, ka, frame->sig.retcode, frame, usig); 583 584 if (err == 0) { 585 /* 586 * For realtime signals we must also set the second and third 587 * arguments for the signal handler. 588 * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06 589 */ 590 regs->ARM_r1 = (unsigned long)&frame->info; 591 regs->ARM_r2 = (unsigned long)&frame->sig.uc; 592 } 593 594 return err; 595 } 596 597 /* 598 * OK, we're invoking a handler 599 */ 600 static int 601 handle_signal(unsigned long sig, struct k_sigaction *ka, 602 siginfo_t *info, sigset_t *oldset, 603 struct pt_regs * regs) 604 { 605 struct thread_info *thread = current_thread_info(); 606 struct task_struct *tsk = current; 607 int usig = sig; 608 int ret; 609 610 /* 611 * translate the signal 612 */ 613 if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap) 614 usig = thread->exec_domain->signal_invmap[usig]; 615 616 /* 617 * Set up the stack frame 618 */ 619 if (ka->sa.sa_flags & SA_SIGINFO) 620 ret = setup_rt_frame(usig, ka, info, oldset, regs); 621 else 622 ret = setup_frame(usig, ka, oldset, regs); 623 624 /* 625 * Check that the resulting registers are actually sane. 626 */ 627 ret |= !valid_user_regs(regs); 628 629 if (ret != 0) { 630 force_sigsegv(sig, tsk); 631 return ret; 632 } 633 634 /* 635 * Block the signal if we were successful. 636 */ 637 block_sigmask(ka, sig); 638 639 return 0; 640 } 641 642 /* 643 * Note that 'init' is a special process: it doesn't get signals it doesn't 644 * want to handle. Thus you cannot kill init even with a SIGKILL even by 645 * mistake. 646 * 647 * Note that we go through the signals twice: once to check the signals that 648 * the kernel can handle, and then we build all the user-level signal handling 649 * stack-frames in one go after that. 650 */ 651 static void do_signal(struct pt_regs *regs, int syscall) 652 { 653 unsigned int retval = 0, continue_addr = 0, restart_addr = 0; 654 struct k_sigaction ka; 655 siginfo_t info; 656 int signr; 657 658 /* 659 * We want the common case to go fast, which 660 * is why we may in certain cases get here from 661 * kernel mode. Just return without doing anything 662 * if so. 663 */ 664 if (!user_mode(regs)) 665 return; 666 667 /* 668 * If we were from a system call, check for system call restarting... 669 */ 670 if (syscall) { 671 continue_addr = regs->ARM_pc; 672 restart_addr = continue_addr - (thumb_mode(regs) ? 2 : 4); 673 retval = regs->ARM_r0; 674 675 /* 676 * Prepare for system call restart. We do this here so that a 677 * debugger will see the already changed PSW. 678 */ 679 switch (retval) { 680 case -ERESTARTNOHAND: 681 case -ERESTARTSYS: 682 case -ERESTARTNOINTR: 683 regs->ARM_r0 = regs->ARM_ORIG_r0; 684 regs->ARM_pc = restart_addr; 685 break; 686 case -ERESTART_RESTARTBLOCK: 687 regs->ARM_r0 = -EINTR; 688 break; 689 } 690 } 691 692 if (try_to_freeze()) 693 goto no_signal; 694 695 /* 696 * Get the signal to deliver. When running under ptrace, at this 697 * point the debugger may change all our registers ... 698 */ 699 signr = get_signal_to_deliver(&info, &ka, regs, NULL); 700 if (signr > 0) { 701 sigset_t *oldset; 702 703 /* 704 * Depending on the signal settings we may need to revert the 705 * decision to restart the system call. But skip this if a 706 * debugger has chosen to restart at a different PC. 707 */ 708 if (regs->ARM_pc == restart_addr) { 709 if (retval == -ERESTARTNOHAND 710 || (retval == -ERESTARTSYS 711 && !(ka.sa.sa_flags & SA_RESTART))) { 712 regs->ARM_r0 = -EINTR; 713 regs->ARM_pc = continue_addr; 714 } 715 } 716 717 if (test_thread_flag(TIF_RESTORE_SIGMASK)) 718 oldset = ¤t->saved_sigmask; 719 else 720 oldset = ¤t->blocked; 721 if (handle_signal(signr, &ka, &info, oldset, regs) == 0) { 722 /* 723 * A signal was successfully delivered; the saved 724 * sigmask will have been stored in the signal frame, 725 * and will be restored by sigreturn, so we can simply 726 * clear the TIF_RESTORE_SIGMASK flag. 727 */ 728 if (test_thread_flag(TIF_RESTORE_SIGMASK)) 729 clear_thread_flag(TIF_RESTORE_SIGMASK); 730 } 731 return; 732 } 733 734 no_signal: 735 if (syscall) { 736 /* 737 * Handle restarting a different system call. As above, 738 * if a debugger has chosen to restart at a different PC, 739 * ignore the restart. 740 */ 741 if (retval == -ERESTART_RESTARTBLOCK 742 && regs->ARM_pc == continue_addr) { 743 if (thumb_mode(regs)) { 744 regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE; 745 regs->ARM_pc -= 2; 746 } else { 747 #if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT) 748 regs->ARM_r7 = __NR_restart_syscall; 749 regs->ARM_pc -= 4; 750 #else 751 u32 __user *usp; 752 753 regs->ARM_sp -= 4; 754 usp = (u32 __user *)regs->ARM_sp; 755 756 if (put_user(regs->ARM_pc, usp) == 0) { 757 regs->ARM_pc = KERN_RESTART_CODE; 758 } else { 759 regs->ARM_sp += 4; 760 force_sigsegv(0, current); 761 } 762 #endif 763 } 764 } 765 766 /* If there's no signal to deliver, we just put the saved sigmask 767 * back. 768 */ 769 if (test_thread_flag(TIF_RESTORE_SIGMASK)) { 770 clear_thread_flag(TIF_RESTORE_SIGMASK); 771 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); 772 } 773 } 774 } 775 776 asmlinkage void 777 do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall) 778 { 779 if (thread_flags & _TIF_SIGPENDING) 780 do_signal(regs, syscall); 781 782 if (thread_flags & _TIF_NOTIFY_RESUME) { 783 clear_thread_flag(TIF_NOTIFY_RESUME); 784 tracehook_notify_resume(regs); 785 if (current->replacement_session_keyring) 786 key_replace_session_keyring(); 787 } 788 } 789