1 /* 2 * linux/arch/sh/kernel/signal.c 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 * 6 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson 7 * 8 * SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima 9 * 10 */ 11 #include <linux/sched.h> 12 #include <linux/mm.h> 13 #include <linux/smp.h> 14 #include <linux/kernel.h> 15 #include <linux/signal.h> 16 #include <linux/errno.h> 17 #include <linux/wait.h> 18 #include <linux/ptrace.h> 19 #include <linux/unistd.h> 20 #include <linux/stddef.h> 21 #include <linux/tty.h> 22 #include <linux/elf.h> 23 #include <linux/personality.h> 24 #include <linux/binfmts.h> 25 #include <linux/io.h> 26 #include <linux/tracehook.h> 27 #include <asm/ucontext.h> 28 #include <asm/uaccess.h> 29 #include <asm/pgtable.h> 30 #include <asm/cacheflush.h> 31 #include <asm/syscalls.h> 32 #include <asm/fpu.h> 33 34 struct fdpic_func_descriptor { 35 unsigned long text; 36 unsigned long GOT; 37 }; 38 39 /* 40 * The following define adds a 64 byte gap between the signal 41 * stack frame and previous contents of the stack. This allows 42 * frame unwinding in a function epilogue but only if a frame 43 * pointer is used in the function. This is necessary because 44 * current gcc compilers (<4.3) do not generate unwind info on 45 * SH for function epilogues. 46 */ 47 #define UNWINDGUARD 64 48 49 /* 50 * Do a signal return; undo the signal stack. 51 */ 52 53 #define MOVW(n) (0x9300|((n)-2)) /* Move mem word at PC+n to R3 */ 54 #if defined(CONFIG_CPU_SH2) 55 #define TRAP_NOARG 0xc320 /* Syscall w/no args (NR in R3) */ 56 #else 57 #define TRAP_NOARG 0xc310 /* Syscall w/no args (NR in R3) */ 58 #endif 59 #define OR_R0_R0 0x200b /* or r0,r0 (insert to avoid hardware bug) */ 60 61 struct sigframe 62 { 63 struct sigcontext sc; 64 unsigned long extramask[_NSIG_WORDS-1]; 65 u16 retcode[8]; 66 }; 67 68 struct rt_sigframe 69 { 70 struct siginfo info; 71 struct ucontext uc; 72 u16 retcode[8]; 73 }; 74 75 #ifdef CONFIG_SH_FPU 76 static inline int restore_sigcontext_fpu(struct sigcontext __user *sc) 77 { 78 struct task_struct *tsk = current; 79 80 if (!(boot_cpu_data.flags & CPU_HAS_FPU)) 81 return 0; 82 83 set_used_math(); 84 return __copy_from_user(&tsk->thread.xstate->hardfpu, &sc->sc_fpregs[0], 85 sizeof(long)*(16*2+2)); 86 } 87 88 static inline int save_sigcontext_fpu(struct sigcontext __user *sc, 89 struct pt_regs *regs) 90 { 91 struct task_struct *tsk = current; 92 93 if (!(boot_cpu_data.flags & CPU_HAS_FPU)) 94 return 0; 95 96 if (!used_math()) 97 return __put_user(0, &sc->sc_ownedfp); 98 99 if (__put_user(1, &sc->sc_ownedfp)) 100 return -EFAULT; 101 102 /* This will cause a "finit" to be triggered by the next 103 attempted FPU operation by the 'current' process. 104 */ 105 clear_used_math(); 106 107 unlazy_fpu(tsk, regs); 108 return __copy_to_user(&sc->sc_fpregs[0], &tsk->thread.xstate->hardfpu, 109 sizeof(long)*(16*2+2)); 110 } 111 #endif /* CONFIG_SH_FPU */ 112 113 static int 114 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p) 115 { 116 unsigned int err = 0; 117 118 #define COPY(x) err |= __get_user(regs->x, &sc->sc_##x) 119 COPY(regs[1]); 120 COPY(regs[2]); COPY(regs[3]); 121 COPY(regs[4]); COPY(regs[5]); 122 COPY(regs[6]); COPY(regs[7]); 123 COPY(regs[8]); COPY(regs[9]); 124 COPY(regs[10]); COPY(regs[11]); 125 COPY(regs[12]); COPY(regs[13]); 126 COPY(regs[14]); COPY(regs[15]); 127 COPY(gbr); COPY(mach); 128 COPY(macl); COPY(pr); 129 COPY(sr); COPY(pc); 130 #undef COPY 131 132 #ifdef CONFIG_SH_FPU 133 if (boot_cpu_data.flags & CPU_HAS_FPU) { 134 int owned_fp; 135 struct task_struct *tsk = current; 136 137 regs->sr |= SR_FD; /* Release FPU */ 138 clear_fpu(tsk, regs); 139 clear_used_math(); 140 err |= __get_user (owned_fp, &sc->sc_ownedfp); 141 if (owned_fp) 142 err |= restore_sigcontext_fpu(sc); 143 } 144 #endif 145 146 regs->tra = -1; /* disable syscall checks */ 147 err |= __get_user(*r0_p, &sc->sc_regs[0]); 148 return err; 149 } 150 151 asmlinkage int sys_sigreturn(void) 152 { 153 struct pt_regs *regs = current_pt_regs(); 154 struct sigframe __user *frame = (struct sigframe __user *)regs->regs[15]; 155 sigset_t set; 156 int r0; 157 158 /* Always make any pending restarted system calls return -EINTR */ 159 current->restart_block.fn = do_no_restart_syscall; 160 161 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 162 goto badframe; 163 164 if (__get_user(set.sig[0], &frame->sc.oldmask) 165 || (_NSIG_WORDS > 1 166 && __copy_from_user(&set.sig[1], &frame->extramask, 167 sizeof(frame->extramask)))) 168 goto badframe; 169 170 set_current_blocked(&set); 171 172 if (restore_sigcontext(regs, &frame->sc, &r0)) 173 goto badframe; 174 return r0; 175 176 badframe: 177 force_sig(SIGSEGV, current); 178 return 0; 179 } 180 181 asmlinkage int sys_rt_sigreturn(void) 182 { 183 struct pt_regs *regs = current_pt_regs(); 184 struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->regs[15]; 185 sigset_t set; 186 int r0; 187 188 /* Always make any pending restarted system calls return -EINTR */ 189 current->restart_block.fn = do_no_restart_syscall; 190 191 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 192 goto badframe; 193 194 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) 195 goto badframe; 196 197 set_current_blocked(&set); 198 199 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0)) 200 goto badframe; 201 202 if (restore_altstack(&frame->uc.uc_stack)) 203 goto badframe; 204 205 return r0; 206 207 badframe: 208 force_sig(SIGSEGV, current); 209 return 0; 210 } 211 212 /* 213 * Set up a signal frame. 214 */ 215 216 static int 217 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, 218 unsigned long mask) 219 { 220 int err = 0; 221 222 #define COPY(x) err |= __put_user(regs->x, &sc->sc_##x) 223 COPY(regs[0]); COPY(regs[1]); 224 COPY(regs[2]); COPY(regs[3]); 225 COPY(regs[4]); COPY(regs[5]); 226 COPY(regs[6]); COPY(regs[7]); 227 COPY(regs[8]); COPY(regs[9]); 228 COPY(regs[10]); COPY(regs[11]); 229 COPY(regs[12]); COPY(regs[13]); 230 COPY(regs[14]); COPY(regs[15]); 231 COPY(gbr); COPY(mach); 232 COPY(macl); COPY(pr); 233 COPY(sr); COPY(pc); 234 #undef COPY 235 236 #ifdef CONFIG_SH_FPU 237 err |= save_sigcontext_fpu(sc, regs); 238 #endif 239 240 /* non-iBCS2 extensions.. */ 241 err |= __put_user(mask, &sc->oldmask); 242 243 return err; 244 } 245 246 /* 247 * Determine which stack to use.. 248 */ 249 static inline void __user * 250 get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size) 251 { 252 if (ka->sa.sa_flags & SA_ONSTACK) { 253 if (sas_ss_flags(sp) == 0) 254 sp = current->sas_ss_sp + current->sas_ss_size; 255 } 256 257 return (void __user *)((sp - (frame_size+UNWINDGUARD)) & -8ul); 258 } 259 260 /* These symbols are defined with the addresses in the vsyscall page. 261 See vsyscall-trapa.S. */ 262 extern void __kernel_sigreturn(void); 263 extern void __kernel_rt_sigreturn(void); 264 265 static int setup_frame(struct ksignal *ksig, sigset_t *set, 266 struct pt_regs *regs) 267 { 268 struct sigframe __user *frame; 269 int err = 0, sig = ksig->sig; 270 int signal; 271 272 frame = get_sigframe(&ksig->ka, regs->regs[15], sizeof(*frame)); 273 274 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 275 return -EFAULT; 276 277 signal = current_thread_info()->exec_domain 278 && current_thread_info()->exec_domain->signal_invmap 279 && sig < 32 280 ? current_thread_info()->exec_domain->signal_invmap[sig] 281 : sig; 282 283 err |= setup_sigcontext(&frame->sc, regs, set->sig[0]); 284 285 if (_NSIG_WORDS > 1) 286 err |= __copy_to_user(frame->extramask, &set->sig[1], 287 sizeof(frame->extramask)); 288 289 /* Set up to return from userspace. If provided, use a stub 290 already in userspace. */ 291 if (ksig->ka.sa.sa_flags & SA_RESTORER) { 292 regs->pr = (unsigned long) ksig->ka.sa.sa_restorer; 293 #ifdef CONFIG_VSYSCALL 294 } else if (likely(current->mm->context.vdso)) { 295 regs->pr = VDSO_SYM(&__kernel_sigreturn); 296 #endif 297 } else { 298 /* Generate return code (system call to sigreturn) */ 299 err |= __put_user(MOVW(7), &frame->retcode[0]); 300 err |= __put_user(TRAP_NOARG, &frame->retcode[1]); 301 err |= __put_user(OR_R0_R0, &frame->retcode[2]); 302 err |= __put_user(OR_R0_R0, &frame->retcode[3]); 303 err |= __put_user(OR_R0_R0, &frame->retcode[4]); 304 err |= __put_user(OR_R0_R0, &frame->retcode[5]); 305 err |= __put_user(OR_R0_R0, &frame->retcode[6]); 306 err |= __put_user((__NR_sigreturn), &frame->retcode[7]); 307 regs->pr = (unsigned long) frame->retcode; 308 flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode)); 309 } 310 311 if (err) 312 return -EFAULT; 313 314 /* Set up registers for signal handler */ 315 regs->regs[15] = (unsigned long) frame; 316 regs->regs[4] = signal; /* Arg for signal handler */ 317 regs->regs[5] = 0; 318 regs->regs[6] = (unsigned long) &frame->sc; 319 320 if (current->personality & FDPIC_FUNCPTRS) { 321 struct fdpic_func_descriptor __user *funcptr = 322 (struct fdpic_func_descriptor __user *)ksig->ka.sa.sa_handler; 323 324 err |= __get_user(regs->pc, &funcptr->text); 325 err |= __get_user(regs->regs[12], &funcptr->GOT); 326 } else 327 regs->pc = (unsigned long)ksig->ka.sa.sa_handler; 328 329 if (err) 330 return -EFAULT; 331 332 set_fs(USER_DS); 333 334 pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n", 335 current->comm, task_pid_nr(current), frame, regs->pc, regs->pr); 336 337 return 0; 338 } 339 340 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set, 341 struct pt_regs *regs) 342 { 343 struct rt_sigframe __user *frame; 344 int err = 0, sig = ksig->sig; 345 int signal; 346 347 frame = get_sigframe(&ksig->ka, regs->regs[15], sizeof(*frame)); 348 349 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 350 return -EFAULT; 351 352 signal = current_thread_info()->exec_domain 353 && current_thread_info()->exec_domain->signal_invmap 354 && sig < 32 355 ? current_thread_info()->exec_domain->signal_invmap[sig] 356 : sig; 357 358 err |= copy_siginfo_to_user(&frame->info, &ksig->info); 359 360 /* Create the ucontext. */ 361 err |= __put_user(0, &frame->uc.uc_flags); 362 err |= __put_user(NULL, &frame->uc.uc_link); 363 err |= __save_altstack(&frame->uc.uc_stack, regs->regs[15]); 364 err |= setup_sigcontext(&frame->uc.uc_mcontext, 365 regs, set->sig[0]); 366 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 367 368 /* Set up to return from userspace. If provided, use a stub 369 already in userspace. */ 370 if (ksig->ka.sa.sa_flags & SA_RESTORER) { 371 regs->pr = (unsigned long) ksig->ka.sa.sa_restorer; 372 #ifdef CONFIG_VSYSCALL 373 } else if (likely(current->mm->context.vdso)) { 374 regs->pr = VDSO_SYM(&__kernel_rt_sigreturn); 375 #endif 376 } else { 377 /* Generate return code (system call to rt_sigreturn) */ 378 err |= __put_user(MOVW(7), &frame->retcode[0]); 379 err |= __put_user(TRAP_NOARG, &frame->retcode[1]); 380 err |= __put_user(OR_R0_R0, &frame->retcode[2]); 381 err |= __put_user(OR_R0_R0, &frame->retcode[3]); 382 err |= __put_user(OR_R0_R0, &frame->retcode[4]); 383 err |= __put_user(OR_R0_R0, &frame->retcode[5]); 384 err |= __put_user(OR_R0_R0, &frame->retcode[6]); 385 err |= __put_user((__NR_rt_sigreturn), &frame->retcode[7]); 386 regs->pr = (unsigned long) frame->retcode; 387 flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode)); 388 } 389 390 if (err) 391 return -EFAULT; 392 393 /* Set up registers for signal handler */ 394 regs->regs[15] = (unsigned long) frame; 395 regs->regs[4] = signal; /* Arg for signal handler */ 396 regs->regs[5] = (unsigned long) &frame->info; 397 regs->regs[6] = (unsigned long) &frame->uc; 398 399 if (current->personality & FDPIC_FUNCPTRS) { 400 struct fdpic_func_descriptor __user *funcptr = 401 (struct fdpic_func_descriptor __user *)ksig->ka.sa.sa_handler; 402 403 err |= __get_user(regs->pc, &funcptr->text); 404 err |= __get_user(regs->regs[12], &funcptr->GOT); 405 } else 406 regs->pc = (unsigned long)ksig->ka.sa.sa_handler; 407 408 if (err) 409 return -EFAULT; 410 411 set_fs(USER_DS); 412 413 pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n", 414 current->comm, task_pid_nr(current), frame, regs->pc, regs->pr); 415 416 return 0; 417 } 418 419 static inline void 420 handle_syscall_restart(unsigned long save_r0, struct pt_regs *regs, 421 struct sigaction *sa) 422 { 423 /* If we're not from a syscall, bail out */ 424 if (regs->tra < 0) 425 return; 426 427 /* check for system call restart.. */ 428 switch (regs->regs[0]) { 429 case -ERESTART_RESTARTBLOCK: 430 case -ERESTARTNOHAND: 431 no_system_call_restart: 432 regs->regs[0] = -EINTR; 433 break; 434 435 case -ERESTARTSYS: 436 if (!(sa->sa_flags & SA_RESTART)) 437 goto no_system_call_restart; 438 /* fallthrough */ 439 case -ERESTARTNOINTR: 440 regs->regs[0] = save_r0; 441 regs->pc -= instruction_size(__raw_readw(regs->pc - 4)); 442 break; 443 } 444 } 445 446 /* 447 * OK, we're invoking a handler 448 */ 449 static void 450 handle_signal(struct ksignal *ksig, struct pt_regs *regs, unsigned int save_r0) 451 { 452 sigset_t *oldset = sigmask_to_save(); 453 int ret; 454 455 /* Set up the stack frame */ 456 if (ksig->ka.sa.sa_flags & SA_SIGINFO) 457 ret = setup_rt_frame(ksig, oldset, regs); 458 else 459 ret = setup_frame(ksig, oldset, regs); 460 461 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP)); 462 } 463 464 /* 465 * Note that 'init' is a special process: it doesn't get signals it doesn't 466 * want to handle. Thus you cannot kill init even with a SIGKILL even by 467 * mistake. 468 * 469 * Note that we go through the signals twice: once to check the signals that 470 * the kernel can handle, and then we build all the user-level signal handling 471 * stack-frames in one go after that. 472 */ 473 static void do_signal(struct pt_regs *regs, unsigned int save_r0) 474 { 475 struct ksignal ksig; 476 477 /* 478 * We want the common case to go fast, which 479 * is why we may in certain cases get here from 480 * kernel mode. Just return without doing anything 481 * if so. 482 */ 483 if (!user_mode(regs)) 484 return; 485 486 if (get_signal(&ksig)) { 487 handle_syscall_restart(save_r0, regs, &ksig.ka.sa); 488 489 /* Whee! Actually deliver the signal. */ 490 handle_signal(&ksig, regs, save_r0); 491 return; 492 } 493 494 /* Did we come from a system call? */ 495 if (regs->tra >= 0) { 496 /* Restart the system call - no handlers present */ 497 if (regs->regs[0] == -ERESTARTNOHAND || 498 regs->regs[0] == -ERESTARTSYS || 499 regs->regs[0] == -ERESTARTNOINTR) { 500 regs->regs[0] = save_r0; 501 regs->pc -= instruction_size(__raw_readw(regs->pc - 4)); 502 } else if (regs->regs[0] == -ERESTART_RESTARTBLOCK) { 503 regs->pc -= instruction_size(__raw_readw(regs->pc - 4)); 504 regs->regs[3] = __NR_restart_syscall; 505 } 506 } 507 508 /* 509 * If there's no signal to deliver, we just put the saved sigmask 510 * back. 511 */ 512 restore_saved_sigmask(); 513 } 514 515 asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int save_r0, 516 unsigned long thread_info_flags) 517 { 518 /* deal with pending signal delivery */ 519 if (thread_info_flags & _TIF_SIGPENDING) 520 do_signal(regs, save_r0); 521 522 if (thread_info_flags & _TIF_NOTIFY_RESUME) { 523 clear_thread_flag(TIF_NOTIFY_RESUME); 524 tracehook_notify_resume(regs); 525 } 526 } 527