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 mask &= _BLOCKABLE; 70 spin_lock_irq(¤t->sighand->siglock); 71 current->saved_sigmask = current->blocked; 72 siginitset(¤t->blocked, mask); 73 recalc_sigpending(); 74 spin_unlock_irq(¤t->sighand->siglock); 75 76 current->state = TASK_INTERRUPTIBLE; 77 schedule(); 78 set_restore_sigmask(); 79 return -ERESTARTNOHAND; 80 } 81 82 asmlinkage int 83 sys_sigaction(int sig, const struct old_sigaction __user *act, 84 struct old_sigaction __user *oact) 85 { 86 struct k_sigaction new_ka, old_ka; 87 int ret; 88 89 if (act) { 90 old_sigset_t mask; 91 if (!access_ok(VERIFY_READ, act, sizeof(*act)) || 92 __get_user(new_ka.sa.sa_handler, &act->sa_handler) || 93 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer)) 94 return -EFAULT; 95 __get_user(new_ka.sa.sa_flags, &act->sa_flags); 96 __get_user(mask, &act->sa_mask); 97 siginitset(&new_ka.sa.sa_mask, mask); 98 } 99 100 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); 101 102 if (!ret && oact) { 103 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || 104 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || 105 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer)) 106 return -EFAULT; 107 __put_user(old_ka.sa.sa_flags, &oact->sa_flags); 108 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask); 109 } 110 111 return ret; 112 } 113 114 #ifdef CONFIG_CRUNCH 115 static int preserve_crunch_context(struct crunch_sigframe __user *frame) 116 { 117 char kbuf[sizeof(*frame) + 8]; 118 struct crunch_sigframe *kframe; 119 120 /* the crunch context must be 64 bit aligned */ 121 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7); 122 kframe->magic = CRUNCH_MAGIC; 123 kframe->size = CRUNCH_STORAGE_SIZE; 124 crunch_task_copy(current_thread_info(), &kframe->storage); 125 return __copy_to_user(frame, kframe, sizeof(*frame)); 126 } 127 128 static int restore_crunch_context(struct crunch_sigframe __user *frame) 129 { 130 char kbuf[sizeof(*frame) + 8]; 131 struct crunch_sigframe *kframe; 132 133 /* the crunch context must be 64 bit aligned */ 134 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7); 135 if (__copy_from_user(kframe, frame, sizeof(*frame))) 136 return -1; 137 if (kframe->magic != CRUNCH_MAGIC || 138 kframe->size != CRUNCH_STORAGE_SIZE) 139 return -1; 140 crunch_task_restore(current_thread_info(), &kframe->storage); 141 return 0; 142 } 143 #endif 144 145 #ifdef CONFIG_IWMMXT 146 147 static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame) 148 { 149 char kbuf[sizeof(*frame) + 8]; 150 struct iwmmxt_sigframe *kframe; 151 152 /* the iWMMXt context must be 64 bit aligned */ 153 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7); 154 kframe->magic = IWMMXT_MAGIC; 155 kframe->size = IWMMXT_STORAGE_SIZE; 156 iwmmxt_task_copy(current_thread_info(), &kframe->storage); 157 return __copy_to_user(frame, kframe, sizeof(*frame)); 158 } 159 160 static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame) 161 { 162 char kbuf[sizeof(*frame) + 8]; 163 struct iwmmxt_sigframe *kframe; 164 165 /* the iWMMXt context must be 64 bit aligned */ 166 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7); 167 if (__copy_from_user(kframe, frame, sizeof(*frame))) 168 return -1; 169 if (kframe->magic != IWMMXT_MAGIC || 170 kframe->size != IWMMXT_STORAGE_SIZE) 171 return -1; 172 iwmmxt_task_restore(current_thread_info(), &kframe->storage); 173 return 0; 174 } 175 176 #endif 177 178 #ifdef CONFIG_VFP 179 180 static int preserve_vfp_context(struct vfp_sigframe __user *frame) 181 { 182 struct thread_info *thread = current_thread_info(); 183 struct vfp_hard_struct *h = &thread->vfpstate.hard; 184 const unsigned long magic = VFP_MAGIC; 185 const unsigned long size = VFP_STORAGE_SIZE; 186 int err = 0; 187 188 vfp_sync_hwstate(thread); 189 __put_user_error(magic, &frame->magic, err); 190 __put_user_error(size, &frame->size, err); 191 192 /* 193 * Copy the floating point registers. There can be unused 194 * registers see asm/hwcap.h for details. 195 */ 196 err |= __copy_to_user(&frame->ufp.fpregs, &h->fpregs, 197 sizeof(h->fpregs)); 198 /* 199 * Copy the status and control register. 200 */ 201 __put_user_error(h->fpscr, &frame->ufp.fpscr, err); 202 203 /* 204 * Copy the exception registers. 205 */ 206 __put_user_error(h->fpexc, &frame->ufp_exc.fpexc, err); 207 __put_user_error(h->fpinst, &frame->ufp_exc.fpinst, err); 208 __put_user_error(h->fpinst2, &frame->ufp_exc.fpinst2, err); 209 210 return err ? -EFAULT : 0; 211 } 212 213 static int restore_vfp_context(struct vfp_sigframe __user *frame) 214 { 215 struct thread_info *thread = current_thread_info(); 216 struct vfp_hard_struct *h = &thread->vfpstate.hard; 217 unsigned long magic; 218 unsigned long size; 219 unsigned long fpexc; 220 int err = 0; 221 222 __get_user_error(magic, &frame->magic, err); 223 __get_user_error(size, &frame->size, err); 224 225 if (err) 226 return -EFAULT; 227 if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE) 228 return -EINVAL; 229 230 /* 231 * Copy the floating point registers. There can be unused 232 * registers see asm/hwcap.h for details. 233 */ 234 err |= __copy_from_user(&h->fpregs, &frame->ufp.fpregs, 235 sizeof(h->fpregs)); 236 /* 237 * Copy the status and control register. 238 */ 239 __get_user_error(h->fpscr, &frame->ufp.fpscr, err); 240 241 /* 242 * Sanitise and restore the exception registers. 243 */ 244 __get_user_error(fpexc, &frame->ufp_exc.fpexc, err); 245 /* Ensure the VFP is enabled. */ 246 fpexc |= FPEXC_EN; 247 /* Ensure FPINST2 is invalid and the exception flag is cleared. */ 248 fpexc &= ~(FPEXC_EX | FPEXC_FP2V); 249 h->fpexc = fpexc; 250 251 __get_user_error(h->fpinst, &frame->ufp_exc.fpinst, err); 252 __get_user_error(h->fpinst2, &frame->ufp_exc.fpinst2, err); 253 254 if (!err) 255 vfp_flush_hwstate(thread); 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 spin_lock_irq(¤t->sighand->siglock); 285 current->blocked = set; 286 recalc_sigpending(); 287 spin_unlock_irq(¤t->sighand->siglock); 288 } 289 290 __get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err); 291 __get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err); 292 __get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err); 293 __get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err); 294 __get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err); 295 __get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err); 296 __get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err); 297 __get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err); 298 __get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err); 299 __get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err); 300 __get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err); 301 __get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err); 302 __get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err); 303 __get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err); 304 __get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err); 305 __get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err); 306 __get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err); 307 308 err |= !valid_user_regs(regs); 309 310 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace; 311 #ifdef CONFIG_CRUNCH 312 if (err == 0) 313 err |= restore_crunch_context(&aux->crunch); 314 #endif 315 #ifdef CONFIG_IWMMXT 316 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT)) 317 err |= restore_iwmmxt_context(&aux->iwmmxt); 318 #endif 319 #ifdef CONFIG_VFP 320 if (err == 0) 321 err |= restore_vfp_context(&aux->vfp); 322 #endif 323 324 return err; 325 } 326 327 asmlinkage int sys_sigreturn(struct pt_regs *regs) 328 { 329 struct sigframe __user *frame; 330 331 /* Always make any pending restarted system calls return -EINTR */ 332 current_thread_info()->restart_block.fn = do_no_restart_syscall; 333 334 /* 335 * Since we stacked the signal on a 64-bit boundary, 336 * then 'sp' should be word aligned here. If it's 337 * not, then the user is trying to mess with us. 338 */ 339 if (regs->ARM_sp & 7) 340 goto badframe; 341 342 frame = (struct sigframe __user *)regs->ARM_sp; 343 344 if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) 345 goto badframe; 346 347 if (restore_sigframe(regs, frame)) 348 goto badframe; 349 350 return regs->ARM_r0; 351 352 badframe: 353 force_sig(SIGSEGV, current); 354 return 0; 355 } 356 357 asmlinkage int sys_rt_sigreturn(struct pt_regs *regs) 358 { 359 struct rt_sigframe __user *frame; 360 361 /* Always make any pending restarted system calls return -EINTR */ 362 current_thread_info()->restart_block.fn = do_no_restart_syscall; 363 364 /* 365 * Since we stacked the signal on a 64-bit boundary, 366 * then 'sp' should be word aligned here. If it's 367 * not, then the user is trying to mess with us. 368 */ 369 if (regs->ARM_sp & 7) 370 goto badframe; 371 372 frame = (struct rt_sigframe __user *)regs->ARM_sp; 373 374 if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) 375 goto badframe; 376 377 if (restore_sigframe(regs, &frame->sig)) 378 goto badframe; 379 380 if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT) 381 goto badframe; 382 383 return regs->ARM_r0; 384 385 badframe: 386 force_sig(SIGSEGV, current); 387 return 0; 388 } 389 390 static int 391 setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set) 392 { 393 struct aux_sigframe __user *aux; 394 int err = 0; 395 396 __put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err); 397 __put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err); 398 __put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err); 399 __put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err); 400 __put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err); 401 __put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err); 402 __put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err); 403 __put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err); 404 __put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err); 405 __put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err); 406 __put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err); 407 __put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err); 408 __put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err); 409 __put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err); 410 __put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err); 411 __put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err); 412 __put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err); 413 414 __put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err); 415 __put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err); 416 __put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err); 417 __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err); 418 419 err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set)); 420 421 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace; 422 #ifdef CONFIG_CRUNCH 423 if (err == 0) 424 err |= preserve_crunch_context(&aux->crunch); 425 #endif 426 #ifdef CONFIG_IWMMXT 427 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT)) 428 err |= preserve_iwmmxt_context(&aux->iwmmxt); 429 #endif 430 #ifdef CONFIG_VFP 431 if (err == 0) 432 err |= preserve_vfp_context(&aux->vfp); 433 #endif 434 __put_user_error(0, &aux->end_magic, err); 435 436 return err; 437 } 438 439 static inline void __user * 440 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize) 441 { 442 unsigned long sp = regs->ARM_sp; 443 void __user *frame; 444 445 /* 446 * This is the X/Open sanctioned signal stack switching. 447 */ 448 if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp)) 449 sp = current->sas_ss_sp + current->sas_ss_size; 450 451 /* 452 * ATPCS B01 mandates 8-byte alignment 453 */ 454 frame = (void __user *)((sp - framesize) & ~7); 455 456 /* 457 * Check that we can actually write to the signal frame. 458 */ 459 if (!access_ok(VERIFY_WRITE, frame, framesize)) 460 frame = NULL; 461 462 return frame; 463 } 464 465 static int 466 setup_return(struct pt_regs *regs, struct k_sigaction *ka, 467 unsigned long __user *rc, void __user *frame, int usig) 468 { 469 unsigned long handler = (unsigned long)ka->sa.sa_handler; 470 unsigned long retcode; 471 int thumb = 0; 472 unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT); 473 474 cpsr |= PSR_ENDSTATE; 475 476 /* 477 * Maybe we need to deliver a 32-bit signal to a 26-bit task. 478 */ 479 if (ka->sa.sa_flags & SA_THIRTYTWO) 480 cpsr = (cpsr & ~MODE_MASK) | USR_MODE; 481 482 #ifdef CONFIG_ARM_THUMB 483 if (elf_hwcap & HWCAP_THUMB) { 484 /* 485 * The LSB of the handler determines if we're going to 486 * be using THUMB or ARM mode for this signal handler. 487 */ 488 thumb = handler & 1; 489 490 if (thumb) { 491 cpsr |= PSR_T_BIT; 492 #if __LINUX_ARM_ARCH__ >= 7 493 /* clear the If-Then Thumb-2 execution state */ 494 cpsr &= ~PSR_IT_MASK; 495 #endif 496 } else 497 cpsr &= ~PSR_T_BIT; 498 } 499 #endif 500 501 if (ka->sa.sa_flags & SA_RESTORER) { 502 retcode = (unsigned long)ka->sa.sa_restorer; 503 } else { 504 unsigned int idx = thumb << 1; 505 506 if (ka->sa.sa_flags & SA_SIGINFO) 507 idx += 3; 508 509 if (__put_user(sigreturn_codes[idx], rc) || 510 __put_user(sigreturn_codes[idx+1], rc+1)) 511 return 1; 512 513 if (cpsr & MODE32_BIT) { 514 /* 515 * 32-bit code can use the new high-page 516 * signal return code support. 517 */ 518 retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb; 519 } else { 520 /* 521 * Ensure that the instruction cache sees 522 * the return code written onto the stack. 523 */ 524 flush_icache_range((unsigned long)rc, 525 (unsigned long)(rc + 2)); 526 527 retcode = ((unsigned long)rc) + thumb; 528 } 529 } 530 531 regs->ARM_r0 = usig; 532 regs->ARM_sp = (unsigned long)frame; 533 regs->ARM_lr = retcode; 534 regs->ARM_pc = handler; 535 regs->ARM_cpsr = cpsr; 536 537 return 0; 538 } 539 540 static int 541 setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs) 542 { 543 struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame)); 544 int err = 0; 545 546 if (!frame) 547 return 1; 548 549 /* 550 * Set uc.uc_flags to a value which sc.trap_no would never have. 551 */ 552 __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err); 553 554 err |= setup_sigframe(frame, regs, set); 555 if (err == 0) 556 err = setup_return(regs, ka, frame->retcode, frame, usig); 557 558 return err; 559 } 560 561 static int 562 setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info, 563 sigset_t *set, struct pt_regs *regs) 564 { 565 struct rt_sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame)); 566 stack_t stack; 567 int err = 0; 568 569 if (!frame) 570 return 1; 571 572 err |= copy_siginfo_to_user(&frame->info, info); 573 574 __put_user_error(0, &frame->sig.uc.uc_flags, err); 575 __put_user_error(NULL, &frame->sig.uc.uc_link, err); 576 577 memset(&stack, 0, sizeof(stack)); 578 stack.ss_sp = (void __user *)current->sas_ss_sp; 579 stack.ss_flags = sas_ss_flags(regs->ARM_sp); 580 stack.ss_size = current->sas_ss_size; 581 err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack)); 582 583 err |= setup_sigframe(&frame->sig, regs, set); 584 if (err == 0) 585 err = setup_return(regs, ka, frame->sig.retcode, frame, usig); 586 587 if (err == 0) { 588 /* 589 * For realtime signals we must also set the second and third 590 * arguments for the signal handler. 591 * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06 592 */ 593 regs->ARM_r1 = (unsigned long)&frame->info; 594 regs->ARM_r2 = (unsigned long)&frame->sig.uc; 595 } 596 597 return err; 598 } 599 600 /* 601 * OK, we're invoking a handler 602 */ 603 static int 604 handle_signal(unsigned long sig, struct k_sigaction *ka, 605 siginfo_t *info, sigset_t *oldset, 606 struct pt_regs * regs) 607 { 608 struct thread_info *thread = current_thread_info(); 609 struct task_struct *tsk = current; 610 int usig = sig; 611 int ret; 612 613 /* 614 * translate the signal 615 */ 616 if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap) 617 usig = thread->exec_domain->signal_invmap[usig]; 618 619 /* 620 * Set up the stack frame 621 */ 622 if (ka->sa.sa_flags & SA_SIGINFO) 623 ret = setup_rt_frame(usig, ka, info, oldset, regs); 624 else 625 ret = setup_frame(usig, ka, oldset, regs); 626 627 /* 628 * Check that the resulting registers are actually sane. 629 */ 630 ret |= !valid_user_regs(regs); 631 632 if (ret != 0) { 633 force_sigsegv(sig, tsk); 634 return ret; 635 } 636 637 /* 638 * Block the signal if we were successful. 639 */ 640 spin_lock_irq(&tsk->sighand->siglock); 641 sigorsets(&tsk->blocked, &tsk->blocked, 642 &ka->sa.sa_mask); 643 if (!(ka->sa.sa_flags & SA_NODEFER)) 644 sigaddset(&tsk->blocked, sig); 645 recalc_sigpending(); 646 spin_unlock_irq(&tsk->sighand->siglock); 647 648 return 0; 649 } 650 651 /* 652 * Note that 'init' is a special process: it doesn't get signals it doesn't 653 * want to handle. Thus you cannot kill init even with a SIGKILL even by 654 * mistake. 655 * 656 * Note that we go through the signals twice: once to check the signals that 657 * the kernel can handle, and then we build all the user-level signal handling 658 * stack-frames in one go after that. 659 */ 660 static void do_signal(struct pt_regs *regs, int syscall) 661 { 662 unsigned int retval = 0, continue_addr = 0, restart_addr = 0; 663 struct k_sigaction ka; 664 siginfo_t info; 665 int signr; 666 667 /* 668 * We want the common case to go fast, which 669 * is why we may in certain cases get here from 670 * kernel mode. Just return without doing anything 671 * if so. 672 */ 673 if (!user_mode(regs)) 674 return; 675 676 /* 677 * If we were from a system call, check for system call restarting... 678 */ 679 if (syscall) { 680 continue_addr = regs->ARM_pc; 681 restart_addr = continue_addr - (thumb_mode(regs) ? 2 : 4); 682 retval = regs->ARM_r0; 683 684 /* 685 * Prepare for system call restart. We do this here so that a 686 * debugger will see the already changed PSW. 687 */ 688 switch (retval) { 689 case -ERESTARTNOHAND: 690 case -ERESTARTSYS: 691 case -ERESTARTNOINTR: 692 regs->ARM_r0 = regs->ARM_ORIG_r0; 693 regs->ARM_pc = restart_addr; 694 break; 695 case -ERESTART_RESTARTBLOCK: 696 regs->ARM_r0 = -EINTR; 697 break; 698 } 699 } 700 701 if (try_to_freeze()) 702 goto no_signal; 703 704 /* 705 * Get the signal to deliver. When running under ptrace, at this 706 * point the debugger may change all our registers ... 707 */ 708 signr = get_signal_to_deliver(&info, &ka, regs, NULL); 709 if (signr > 0) { 710 sigset_t *oldset; 711 712 /* 713 * Depending on the signal settings we may need to revert the 714 * decision to restart the system call. But skip this if a 715 * debugger has chosen to restart at a different PC. 716 */ 717 if (regs->ARM_pc == restart_addr) { 718 if (retval == -ERESTARTNOHAND 719 || (retval == -ERESTARTSYS 720 && !(ka.sa.sa_flags & SA_RESTART))) { 721 regs->ARM_r0 = -EINTR; 722 regs->ARM_pc = continue_addr; 723 } 724 } 725 726 if (test_thread_flag(TIF_RESTORE_SIGMASK)) 727 oldset = ¤t->saved_sigmask; 728 else 729 oldset = ¤t->blocked; 730 if (handle_signal(signr, &ka, &info, oldset, regs) == 0) { 731 /* 732 * A signal was successfully delivered; the saved 733 * sigmask will have been stored in the signal frame, 734 * and will be restored by sigreturn, so we can simply 735 * clear the TIF_RESTORE_SIGMASK flag. 736 */ 737 if (test_thread_flag(TIF_RESTORE_SIGMASK)) 738 clear_thread_flag(TIF_RESTORE_SIGMASK); 739 } 740 return; 741 } 742 743 no_signal: 744 if (syscall) { 745 /* 746 * Handle restarting a different system call. As above, 747 * if a debugger has chosen to restart at a different PC, 748 * ignore the restart. 749 */ 750 if (retval == -ERESTART_RESTARTBLOCK 751 && regs->ARM_pc == continue_addr) { 752 if (thumb_mode(regs)) { 753 regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE; 754 regs->ARM_pc -= 2; 755 } else { 756 #if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT) 757 regs->ARM_r7 = __NR_restart_syscall; 758 regs->ARM_pc -= 4; 759 #else 760 u32 __user *usp; 761 762 regs->ARM_sp -= 4; 763 usp = (u32 __user *)regs->ARM_sp; 764 765 if (put_user(regs->ARM_pc, usp) == 0) { 766 regs->ARM_pc = KERN_RESTART_CODE; 767 } else { 768 regs->ARM_sp += 4; 769 force_sigsegv(0, current); 770 } 771 #endif 772 } 773 } 774 775 /* If there's no signal to deliver, we just put the saved sigmask 776 * back. 777 */ 778 if (test_thread_flag(TIF_RESTORE_SIGMASK)) { 779 clear_thread_flag(TIF_RESTORE_SIGMASK); 780 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); 781 } 782 } 783 } 784 785 asmlinkage void 786 do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall) 787 { 788 if (thread_flags & _TIF_SIGPENDING) 789 do_signal(regs, syscall); 790 791 if (thread_flags & _TIF_NOTIFY_RESUME) { 792 clear_thread_flag(TIF_NOTIFY_RESUME); 793 tracehook_notify_resume(regs); 794 if (current->replacement_session_keyring) 795 key_replace_session_keyring(); 796 } 797 } 798