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 vfp_flush_hwstate(thread); 231 232 /* 233 * Copy the floating point registers. There can be unused 234 * registers see asm/hwcap.h for details. 235 */ 236 err |= __copy_from_user(&h->fpregs, &frame->ufp.fpregs, 237 sizeof(h->fpregs)); 238 /* 239 * Copy the status and control register. 240 */ 241 __get_user_error(h->fpscr, &frame->ufp.fpscr, err); 242 243 /* 244 * Sanitise and restore the exception registers. 245 */ 246 __get_user_error(fpexc, &frame->ufp_exc.fpexc, err); 247 /* Ensure the VFP is enabled. */ 248 fpexc |= FPEXC_EN; 249 /* Ensure FPINST2 is invalid and the exception flag is cleared. */ 250 fpexc &= ~(FPEXC_EX | FPEXC_FP2V); 251 h->fpexc = fpexc; 252 253 __get_user_error(h->fpinst, &frame->ufp_exc.fpinst, err); 254 __get_user_error(h->fpinst2, &frame->ufp_exc.fpinst2, err); 255 256 return err ? -EFAULT : 0; 257 } 258 259 #endif 260 261 /* 262 * Do a signal return; undo the signal stack. These are aligned to 64-bit. 263 */ 264 struct sigframe { 265 struct ucontext uc; 266 unsigned long retcode[2]; 267 }; 268 269 struct rt_sigframe { 270 struct siginfo info; 271 struct sigframe sig; 272 }; 273 274 static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf) 275 { 276 struct aux_sigframe __user *aux; 277 sigset_t set; 278 int err; 279 280 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set)); 281 if (err == 0) { 282 sigdelsetmask(&set, ~_BLOCKABLE); 283 spin_lock_irq(¤t->sighand->siglock); 284 current->blocked = set; 285 recalc_sigpending(); 286 spin_unlock_irq(¤t->sighand->siglock); 287 } 288 289 __get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err); 290 __get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err); 291 __get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err); 292 __get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err); 293 __get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err); 294 __get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err); 295 __get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err); 296 __get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err); 297 __get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err); 298 __get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err); 299 __get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err); 300 __get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err); 301 __get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err); 302 __get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err); 303 __get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err); 304 __get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err); 305 __get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err); 306 307 err |= !valid_user_regs(regs); 308 309 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace; 310 #ifdef CONFIG_CRUNCH 311 if (err == 0) 312 err |= restore_crunch_context(&aux->crunch); 313 #endif 314 #ifdef CONFIG_IWMMXT 315 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT)) 316 err |= restore_iwmmxt_context(&aux->iwmmxt); 317 #endif 318 #ifdef CONFIG_VFP 319 if (err == 0) 320 err |= restore_vfp_context(&aux->vfp); 321 #endif 322 323 return err; 324 } 325 326 asmlinkage int sys_sigreturn(struct pt_regs *regs) 327 { 328 struct sigframe __user *frame; 329 330 /* Always make any pending restarted system calls return -EINTR */ 331 current_thread_info()->restart_block.fn = do_no_restart_syscall; 332 333 /* 334 * Since we stacked the signal on a 64-bit boundary, 335 * then 'sp' should be word aligned here. If it's 336 * not, then the user is trying to mess with us. 337 */ 338 if (regs->ARM_sp & 7) 339 goto badframe; 340 341 frame = (struct sigframe __user *)regs->ARM_sp; 342 343 if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) 344 goto badframe; 345 346 if (restore_sigframe(regs, frame)) 347 goto badframe; 348 349 return regs->ARM_r0; 350 351 badframe: 352 force_sig(SIGSEGV, current); 353 return 0; 354 } 355 356 asmlinkage int sys_rt_sigreturn(struct pt_regs *regs) 357 { 358 struct rt_sigframe __user *frame; 359 360 /* Always make any pending restarted system calls return -EINTR */ 361 current_thread_info()->restart_block.fn = do_no_restart_syscall; 362 363 /* 364 * Since we stacked the signal on a 64-bit boundary, 365 * then 'sp' should be word aligned here. If it's 366 * not, then the user is trying to mess with us. 367 */ 368 if (regs->ARM_sp & 7) 369 goto badframe; 370 371 frame = (struct rt_sigframe __user *)regs->ARM_sp; 372 373 if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) 374 goto badframe; 375 376 if (restore_sigframe(regs, &frame->sig)) 377 goto badframe; 378 379 if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT) 380 goto badframe; 381 382 return regs->ARM_r0; 383 384 badframe: 385 force_sig(SIGSEGV, current); 386 return 0; 387 } 388 389 static int 390 setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set) 391 { 392 struct aux_sigframe __user *aux; 393 int err = 0; 394 395 __put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err); 396 __put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err); 397 __put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err); 398 __put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err); 399 __put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err); 400 __put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err); 401 __put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err); 402 __put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err); 403 __put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err); 404 __put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err); 405 __put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err); 406 __put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err); 407 __put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err); 408 __put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err); 409 __put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err); 410 __put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err); 411 __put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err); 412 413 __put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err); 414 __put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err); 415 __put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err); 416 __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err); 417 418 err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set)); 419 420 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace; 421 #ifdef CONFIG_CRUNCH 422 if (err == 0) 423 err |= preserve_crunch_context(&aux->crunch); 424 #endif 425 #ifdef CONFIG_IWMMXT 426 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT)) 427 err |= preserve_iwmmxt_context(&aux->iwmmxt); 428 #endif 429 #ifdef CONFIG_VFP 430 if (err == 0) 431 err |= preserve_vfp_context(&aux->vfp); 432 #endif 433 __put_user_error(0, &aux->end_magic, err); 434 435 return err; 436 } 437 438 static inline void __user * 439 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize) 440 { 441 unsigned long sp = regs->ARM_sp; 442 void __user *frame; 443 444 /* 445 * This is the X/Open sanctioned signal stack switching. 446 */ 447 if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp)) 448 sp = current->sas_ss_sp + current->sas_ss_size; 449 450 /* 451 * ATPCS B01 mandates 8-byte alignment 452 */ 453 frame = (void __user *)((sp - framesize) & ~7); 454 455 /* 456 * Check that we can actually write to the signal frame. 457 */ 458 if (!access_ok(VERIFY_WRITE, frame, framesize)) 459 frame = NULL; 460 461 return frame; 462 } 463 464 static int 465 setup_return(struct pt_regs *regs, struct k_sigaction *ka, 466 unsigned long __user *rc, void __user *frame, int usig) 467 { 468 unsigned long handler = (unsigned long)ka->sa.sa_handler; 469 unsigned long retcode; 470 int thumb = 0; 471 unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT); 472 473 cpsr |= PSR_ENDSTATE; 474 475 /* 476 * Maybe we need to deliver a 32-bit signal to a 26-bit task. 477 */ 478 if (ka->sa.sa_flags & SA_THIRTYTWO) 479 cpsr = (cpsr & ~MODE_MASK) | USR_MODE; 480 481 #ifdef CONFIG_ARM_THUMB 482 if (elf_hwcap & HWCAP_THUMB) { 483 /* 484 * The LSB of the handler determines if we're going to 485 * be using THUMB or ARM mode for this signal handler. 486 */ 487 thumb = handler & 1; 488 489 if (thumb) { 490 cpsr |= PSR_T_BIT; 491 #if __LINUX_ARM_ARCH__ >= 7 492 /* clear the If-Then Thumb-2 execution state */ 493 cpsr &= ~PSR_IT_MASK; 494 #endif 495 } else 496 cpsr &= ~PSR_T_BIT; 497 } 498 #endif 499 500 if (ka->sa.sa_flags & SA_RESTORER) { 501 retcode = (unsigned long)ka->sa.sa_restorer; 502 } else { 503 unsigned int idx = thumb << 1; 504 505 if (ka->sa.sa_flags & SA_SIGINFO) 506 idx += 3; 507 508 if (__put_user(sigreturn_codes[idx], rc) || 509 __put_user(sigreturn_codes[idx+1], rc+1)) 510 return 1; 511 512 if (cpsr & MODE32_BIT) { 513 /* 514 * 32-bit code can use the new high-page 515 * signal return code support. 516 */ 517 retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb; 518 } else { 519 /* 520 * Ensure that the instruction cache sees 521 * the return code written onto the stack. 522 */ 523 flush_icache_range((unsigned long)rc, 524 (unsigned long)(rc + 2)); 525 526 retcode = ((unsigned long)rc) + thumb; 527 } 528 } 529 530 regs->ARM_r0 = usig; 531 regs->ARM_sp = (unsigned long)frame; 532 regs->ARM_lr = retcode; 533 regs->ARM_pc = handler; 534 regs->ARM_cpsr = cpsr; 535 536 return 0; 537 } 538 539 static int 540 setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs) 541 { 542 struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame)); 543 int err = 0; 544 545 if (!frame) 546 return 1; 547 548 /* 549 * Set uc.uc_flags to a value which sc.trap_no would never have. 550 */ 551 __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err); 552 553 err |= setup_sigframe(frame, regs, set); 554 if (err == 0) 555 err = setup_return(regs, ka, frame->retcode, frame, usig); 556 557 return err; 558 } 559 560 static int 561 setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info, 562 sigset_t *set, struct pt_regs *regs) 563 { 564 struct rt_sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame)); 565 stack_t stack; 566 int err = 0; 567 568 if (!frame) 569 return 1; 570 571 err |= copy_siginfo_to_user(&frame->info, info); 572 573 __put_user_error(0, &frame->sig.uc.uc_flags, err); 574 __put_user_error(NULL, &frame->sig.uc.uc_link, err); 575 576 memset(&stack, 0, sizeof(stack)); 577 stack.ss_sp = (void __user *)current->sas_ss_sp; 578 stack.ss_flags = sas_ss_flags(regs->ARM_sp); 579 stack.ss_size = current->sas_ss_size; 580 err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack)); 581 582 err |= setup_sigframe(&frame->sig, regs, set); 583 if (err == 0) 584 err = setup_return(regs, ka, frame->sig.retcode, frame, usig); 585 586 if (err == 0) { 587 /* 588 * For realtime signals we must also set the second and third 589 * arguments for the signal handler. 590 * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06 591 */ 592 regs->ARM_r1 = (unsigned long)&frame->info; 593 regs->ARM_r2 = (unsigned long)&frame->sig.uc; 594 } 595 596 return err; 597 } 598 599 /* 600 * OK, we're invoking a handler 601 */ 602 static int 603 handle_signal(unsigned long sig, struct k_sigaction *ka, 604 siginfo_t *info, sigset_t *oldset, 605 struct pt_regs * regs) 606 { 607 struct thread_info *thread = current_thread_info(); 608 struct task_struct *tsk = current; 609 int usig = sig; 610 int ret; 611 612 /* 613 * translate the signal 614 */ 615 if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap) 616 usig = thread->exec_domain->signal_invmap[usig]; 617 618 /* 619 * Set up the stack frame 620 */ 621 if (ka->sa.sa_flags & SA_SIGINFO) 622 ret = setup_rt_frame(usig, ka, info, oldset, regs); 623 else 624 ret = setup_frame(usig, ka, oldset, regs); 625 626 /* 627 * Check that the resulting registers are actually sane. 628 */ 629 ret |= !valid_user_regs(regs); 630 631 if (ret != 0) { 632 force_sigsegv(sig, tsk); 633 return ret; 634 } 635 636 /* 637 * Block the signal if we were successful. 638 */ 639 spin_lock_irq(&tsk->sighand->siglock); 640 sigorsets(&tsk->blocked, &tsk->blocked, 641 &ka->sa.sa_mask); 642 if (!(ka->sa.sa_flags & SA_NODEFER)) 643 sigaddset(&tsk->blocked, sig); 644 recalc_sigpending(); 645 spin_unlock_irq(&tsk->sighand->siglock); 646 647 return 0; 648 } 649 650 /* 651 * Note that 'init' is a special process: it doesn't get signals it doesn't 652 * want to handle. Thus you cannot kill init even with a SIGKILL even by 653 * mistake. 654 * 655 * Note that we go through the signals twice: once to check the signals that 656 * the kernel can handle, and then we build all the user-level signal handling 657 * stack-frames in one go after that. 658 */ 659 static void do_signal(struct pt_regs *regs, int syscall) 660 { 661 unsigned int retval = 0, continue_addr = 0, restart_addr = 0; 662 struct k_sigaction ka; 663 siginfo_t info; 664 int signr; 665 666 /* 667 * We want the common case to go fast, which 668 * is why we may in certain cases get here from 669 * kernel mode. Just return without doing anything 670 * if so. 671 */ 672 if (!user_mode(regs)) 673 return; 674 675 /* 676 * If we were from a system call, check for system call restarting... 677 */ 678 if (syscall) { 679 continue_addr = regs->ARM_pc; 680 restart_addr = continue_addr - (thumb_mode(regs) ? 2 : 4); 681 retval = regs->ARM_r0; 682 683 /* 684 * Prepare for system call restart. We do this here so that a 685 * debugger will see the already changed PSW. 686 */ 687 switch (retval) { 688 case -ERESTARTNOHAND: 689 case -ERESTARTSYS: 690 case -ERESTARTNOINTR: 691 regs->ARM_r0 = regs->ARM_ORIG_r0; 692 regs->ARM_pc = restart_addr; 693 break; 694 case -ERESTART_RESTARTBLOCK: 695 regs->ARM_r0 = -EINTR; 696 break; 697 } 698 } 699 700 if (try_to_freeze()) 701 goto no_signal; 702 703 /* 704 * Get the signal to deliver. When running under ptrace, at this 705 * point the debugger may change all our registers ... 706 */ 707 signr = get_signal_to_deliver(&info, &ka, regs, NULL); 708 if (signr > 0) { 709 sigset_t *oldset; 710 711 /* 712 * Depending on the signal settings we may need to revert the 713 * decision to restart the system call. But skip this if a 714 * debugger has chosen to restart at a different PC. 715 */ 716 if (regs->ARM_pc == restart_addr) { 717 if (retval == -ERESTARTNOHAND 718 || (retval == -ERESTARTSYS 719 && !(ka.sa.sa_flags & SA_RESTART))) { 720 regs->ARM_r0 = -EINTR; 721 regs->ARM_pc = continue_addr; 722 } 723 } 724 725 if (test_thread_flag(TIF_RESTORE_SIGMASK)) 726 oldset = ¤t->saved_sigmask; 727 else 728 oldset = ¤t->blocked; 729 if (handle_signal(signr, &ka, &info, oldset, regs) == 0) { 730 /* 731 * A signal was successfully delivered; the saved 732 * sigmask will have been stored in the signal frame, 733 * and will be restored by sigreturn, so we can simply 734 * clear the TIF_RESTORE_SIGMASK flag. 735 */ 736 if (test_thread_flag(TIF_RESTORE_SIGMASK)) 737 clear_thread_flag(TIF_RESTORE_SIGMASK); 738 } 739 return; 740 } 741 742 no_signal: 743 if (syscall) { 744 /* 745 * Handle restarting a different system call. As above, 746 * if a debugger has chosen to restart at a different PC, 747 * ignore the restart. 748 */ 749 if (retval == -ERESTART_RESTARTBLOCK 750 && regs->ARM_pc == continue_addr) { 751 if (thumb_mode(regs)) { 752 regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE; 753 regs->ARM_pc -= 2; 754 } else { 755 #if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT) 756 regs->ARM_r7 = __NR_restart_syscall; 757 regs->ARM_pc -= 4; 758 #else 759 u32 __user *usp; 760 761 regs->ARM_sp -= 4; 762 usp = (u32 __user *)regs->ARM_sp; 763 764 if (put_user(regs->ARM_pc, usp) == 0) { 765 regs->ARM_pc = KERN_RESTART_CODE; 766 } else { 767 regs->ARM_sp += 4; 768 force_sigsegv(0, current); 769 } 770 #endif 771 } 772 } 773 774 /* If there's no signal to deliver, we just put the saved sigmask 775 * back. 776 */ 777 if (test_thread_flag(TIF_RESTORE_SIGMASK)) { 778 clear_thread_flag(TIF_RESTORE_SIGMASK); 779 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); 780 } 781 } 782 } 783 784 asmlinkage void 785 do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall) 786 { 787 if (thread_flags & _TIF_SIGPENDING) 788 do_signal(regs, syscall); 789 790 if (thread_flags & _TIF_NOTIFY_RESUME) { 791 clear_thread_flag(TIF_NOTIFY_RESUME); 792 tracehook_notify_resume(regs); 793 if (current->replacement_session_keyring) 794 key_replace_session_keyring(); 795 } 796 } 797