1 /* 2 * linux/arch/parisc/kernel/signal.c: Architecture-specific signal 3 * handling support. 4 * 5 * Copyright (C) 2000 David Huggins-Daines <dhd@debian.org> 6 * Copyright (C) 2000 Linuxcare, Inc. 7 * 8 * Based on the ia64, i386, and alpha versions. 9 * 10 * Like the IA-64, we are a recent enough port (we are *starting* 11 * with glibc2.2) that we do not need to support the old non-realtime 12 * Linux signals. Therefore we don't. 13 */ 14 15 #include <linux/sched.h> 16 #include <linux/mm.h> 17 #include <linux/smp.h> 18 #include <linux/kernel.h> 19 #include <linux/signal.h> 20 #include <linux/errno.h> 21 #include <linux/wait.h> 22 #include <linux/ptrace.h> 23 #include <linux/tracehook.h> 24 #include <linux/unistd.h> 25 #include <linux/stddef.h> 26 #include <linux/compat.h> 27 #include <linux/elf.h> 28 #include <asm/ucontext.h> 29 #include <asm/rt_sigframe.h> 30 #include <asm/uaccess.h> 31 #include <asm/pgalloc.h> 32 #include <asm/cacheflush.h> 33 #include <asm/asm-offsets.h> 34 35 #ifdef CONFIG_COMPAT 36 #include "signal32.h" 37 #endif 38 39 #define DEBUG_SIG 0 40 #define DEBUG_SIG_LEVEL 2 41 42 #if DEBUG_SIG 43 #define DBG(LEVEL, ...) \ 44 ((DEBUG_SIG_LEVEL >= LEVEL) \ 45 ? printk(__VA_ARGS__) : (void) 0) 46 #else 47 #define DBG(LEVEL, ...) 48 #endif 49 50 /* gcc will complain if a pointer is cast to an integer of different 51 * size. If you really need to do this (and we do for an ELF32 user 52 * application in an ELF64 kernel) then you have to do a cast to an 53 * integer of the same size first. The A() macro accomplishes 54 * this. */ 55 #define A(__x) ((unsigned long)(__x)) 56 57 /* 58 * Do a signal return - restore sigcontext. 59 */ 60 61 /* Trampoline for calling rt_sigreturn() */ 62 #define INSN_LDI_R25_0 0x34190000 /* ldi 0,%r25 (in_syscall=0) */ 63 #define INSN_LDI_R25_1 0x34190002 /* ldi 1,%r25 (in_syscall=1) */ 64 #define INSN_LDI_R20 0x3414015a /* ldi __NR_rt_sigreturn,%r20 */ 65 #define INSN_BLE_SR2_R0 0xe4008200 /* be,l 0x100(%sr2,%r0),%sr0,%r31 */ 66 #define INSN_NOP 0x08000240 /* nop */ 67 /* For debugging */ 68 #define INSN_DIE_HORRIBLY 0x68000ccc /* stw %r0,0x666(%sr0,%r0) */ 69 70 static long 71 restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs) 72 { 73 long err = 0; 74 75 err |= __copy_from_user(regs->gr, sc->sc_gr, sizeof(regs->gr)); 76 err |= __copy_from_user(regs->fr, sc->sc_fr, sizeof(regs->fr)); 77 err |= __copy_from_user(regs->iaoq, sc->sc_iaoq, sizeof(regs->iaoq)); 78 err |= __copy_from_user(regs->iasq, sc->sc_iasq, sizeof(regs->iasq)); 79 err |= __get_user(regs->sar, &sc->sc_sar); 80 DBG(2,"restore_sigcontext: iaoq is %#lx / %#lx\n", 81 regs->iaoq[0],regs->iaoq[1]); 82 DBG(2,"restore_sigcontext: r28 is %ld\n", regs->gr[28]); 83 return err; 84 } 85 86 void 87 sys_rt_sigreturn(struct pt_regs *regs, int in_syscall) 88 { 89 struct rt_sigframe __user *frame; 90 sigset_t set; 91 unsigned long usp = (regs->gr[30] & ~(0x01UL)); 92 unsigned long sigframe_size = PARISC_RT_SIGFRAME_SIZE; 93 #ifdef CONFIG_64BIT 94 compat_sigset_t compat_set; 95 struct compat_rt_sigframe __user * compat_frame; 96 97 if (is_compat_task()) 98 sigframe_size = PARISC_RT_SIGFRAME_SIZE32; 99 #endif 100 101 current->restart_block.fn = do_no_restart_syscall; 102 103 /* Unwind the user stack to get the rt_sigframe structure. */ 104 frame = (struct rt_sigframe __user *) 105 (usp - sigframe_size); 106 DBG(2,"sys_rt_sigreturn: frame is %p\n", frame); 107 108 regs->orig_r28 = 1; /* no restarts for sigreturn */ 109 110 #ifdef CONFIG_64BIT 111 compat_frame = (struct compat_rt_sigframe __user *)frame; 112 113 if (is_compat_task()) { 114 DBG(2,"sys_rt_sigreturn: ELF32 process.\n"); 115 if (__copy_from_user(&compat_set, &compat_frame->uc.uc_sigmask, sizeof(compat_set))) 116 goto give_sigsegv; 117 sigset_32to64(&set,&compat_set); 118 } else 119 #endif 120 { 121 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) 122 goto give_sigsegv; 123 } 124 125 set_current_blocked(&set); 126 127 /* Good thing we saved the old gr[30], eh? */ 128 #ifdef CONFIG_64BIT 129 if (is_compat_task()) { 130 DBG(1,"sys_rt_sigreturn: compat_frame->uc.uc_mcontext 0x%p\n", 131 &compat_frame->uc.uc_mcontext); 132 // FIXME: Load upper half from register file 133 if (restore_sigcontext32(&compat_frame->uc.uc_mcontext, 134 &compat_frame->regs, regs)) 135 goto give_sigsegv; 136 DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n", 137 usp, &compat_frame->uc.uc_stack); 138 if (compat_restore_altstack(&compat_frame->uc.uc_stack)) 139 goto give_sigsegv; 140 } else 141 #endif 142 { 143 DBG(1,"sys_rt_sigreturn: frame->uc.uc_mcontext 0x%p\n", 144 &frame->uc.uc_mcontext); 145 if (restore_sigcontext(&frame->uc.uc_mcontext, regs)) 146 goto give_sigsegv; 147 DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n", 148 usp, &frame->uc.uc_stack); 149 if (restore_altstack(&frame->uc.uc_stack)) 150 goto give_sigsegv; 151 } 152 153 154 155 /* If we are on the syscall path IAOQ will not be restored, and 156 * if we are on the interrupt path we must not corrupt gr31. 157 */ 158 if (in_syscall) 159 regs->gr[31] = regs->iaoq[0]; 160 #if DEBUG_SIG 161 DBG(1,"sys_rt_sigreturn: returning to %#lx, DUMPING REGS:\n", regs->iaoq[0]); 162 show_regs(regs); 163 #endif 164 return; 165 166 give_sigsegv: 167 DBG(1,"sys_rt_sigreturn: Sending SIGSEGV\n"); 168 force_sig(SIGSEGV, current); 169 return; 170 } 171 172 /* 173 * Set up a signal frame. 174 */ 175 176 static inline void __user * 177 get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size) 178 { 179 /*FIXME: ELF32 vs. ELF64 has different frame_size, but since we 180 don't use the parameter it doesn't matter */ 181 182 DBG(1,"get_sigframe: ka = %#lx, sp = %#lx, frame_size = %#lx\n", 183 (unsigned long)ka, sp, frame_size); 184 185 /* Align alternate stack and reserve 64 bytes for the signal 186 handler's frame marker. */ 187 if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp)) 188 sp = (current->sas_ss_sp + 0x7f) & ~0x3f; /* Stacks grow up! */ 189 190 DBG(1,"get_sigframe: Returning sp = %#lx\n", (unsigned long)sp); 191 return (void __user *) sp; /* Stacks grow up. Fun. */ 192 } 193 194 static long 195 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, int in_syscall) 196 197 { 198 unsigned long flags = 0; 199 long err = 0; 200 201 if (on_sig_stack((unsigned long) sc)) 202 flags |= PARISC_SC_FLAG_ONSTACK; 203 if (in_syscall) { 204 flags |= PARISC_SC_FLAG_IN_SYSCALL; 205 /* regs->iaoq is undefined in the syscall return path */ 206 err |= __put_user(regs->gr[31], &sc->sc_iaoq[0]); 207 err |= __put_user(regs->gr[31]+4, &sc->sc_iaoq[1]); 208 err |= __put_user(regs->sr[3], &sc->sc_iasq[0]); 209 err |= __put_user(regs->sr[3], &sc->sc_iasq[1]); 210 DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (in syscall)\n", 211 regs->gr[31], regs->gr[31]+4); 212 } else { 213 err |= __copy_to_user(sc->sc_iaoq, regs->iaoq, sizeof(regs->iaoq)); 214 err |= __copy_to_user(sc->sc_iasq, regs->iasq, sizeof(regs->iasq)); 215 DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (not in syscall)\n", 216 regs->iaoq[0], regs->iaoq[1]); 217 } 218 219 err |= __put_user(flags, &sc->sc_flags); 220 err |= __copy_to_user(sc->sc_gr, regs->gr, sizeof(regs->gr)); 221 err |= __copy_to_user(sc->sc_fr, regs->fr, sizeof(regs->fr)); 222 err |= __put_user(regs->sar, &sc->sc_sar); 223 DBG(1,"setup_sigcontext: r28 is %ld\n", regs->gr[28]); 224 225 return err; 226 } 227 228 static long 229 setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs, 230 int in_syscall) 231 { 232 struct rt_sigframe __user *frame; 233 unsigned long rp, usp; 234 unsigned long haddr, sigframe_size; 235 int err = 0; 236 #ifdef CONFIG_64BIT 237 struct compat_rt_sigframe __user * compat_frame; 238 compat_sigset_t compat_set; 239 #endif 240 241 usp = (regs->gr[30] & ~(0x01UL)); 242 /*FIXME: frame_size parameter is unused, remove it. */ 243 frame = get_sigframe(&ksig->ka, usp, sizeof(*frame)); 244 245 DBG(1,"SETUP_RT_FRAME: START\n"); 246 DBG(1,"setup_rt_frame: frame %p info %p\n", frame, ksig->info); 247 248 249 #ifdef CONFIG_64BIT 250 251 compat_frame = (struct compat_rt_sigframe __user *)frame; 252 253 if (is_compat_task()) { 254 DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &compat_frame->info); 255 err |= copy_siginfo_to_user32(&compat_frame->info, &ksig->info); 256 err |= __compat_save_altstack( &compat_frame->uc.uc_stack, regs->gr[30]); 257 DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &compat_frame->uc); 258 DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &compat_frame->uc.uc_mcontext); 259 err |= setup_sigcontext32(&compat_frame->uc.uc_mcontext, 260 &compat_frame->regs, regs, in_syscall); 261 sigset_64to32(&compat_set,set); 262 err |= __copy_to_user(&compat_frame->uc.uc_sigmask, &compat_set, sizeof(compat_set)); 263 } else 264 #endif 265 { 266 DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &frame->info); 267 err |= copy_siginfo_to_user(&frame->info, &ksig->info); 268 err |= __save_altstack(&frame->uc.uc_stack, regs->gr[30]); 269 DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &frame->uc); 270 DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &frame->uc.uc_mcontext); 271 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, in_syscall); 272 /* FIXME: Should probably be converted as well for the compat case */ 273 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 274 } 275 276 if (err) 277 return -EFAULT; 278 279 /* Set up to return from userspace. If provided, use a stub 280 already in userspace. The first words of tramp are used to 281 save the previous sigrestartblock trampoline that might be 282 on the stack. We start the sigreturn trampoline at 283 SIGRESTARTBLOCK_TRAMP+X. */ 284 err |= __put_user(in_syscall ? INSN_LDI_R25_1 : INSN_LDI_R25_0, 285 &frame->tramp[SIGRESTARTBLOCK_TRAMP+0]); 286 err |= __put_user(INSN_LDI_R20, 287 &frame->tramp[SIGRESTARTBLOCK_TRAMP+1]); 288 err |= __put_user(INSN_BLE_SR2_R0, 289 &frame->tramp[SIGRESTARTBLOCK_TRAMP+2]); 290 err |= __put_user(INSN_NOP, &frame->tramp[SIGRESTARTBLOCK_TRAMP+3]); 291 292 #if DEBUG_SIG 293 /* Assert that we're flushing in the correct space... */ 294 { 295 unsigned long sid; 296 asm ("mfsp %%sr3,%0" : "=r" (sid)); 297 DBG(1,"setup_rt_frame: Flushing 64 bytes at space %#x offset %p\n", 298 sid, frame->tramp); 299 } 300 #endif 301 302 flush_user_dcache_range((unsigned long) &frame->tramp[0], 303 (unsigned long) &frame->tramp[TRAMP_SIZE]); 304 flush_user_icache_range((unsigned long) &frame->tramp[0], 305 (unsigned long) &frame->tramp[TRAMP_SIZE]); 306 307 /* TRAMP Words 0-4, Length 5 = SIGRESTARTBLOCK_TRAMP 308 * TRAMP Words 5-9, Length 4 = SIGRETURN_TRAMP 309 * So the SIGRETURN_TRAMP is at the end of SIGRESTARTBLOCK_TRAMP 310 */ 311 rp = (unsigned long) &frame->tramp[SIGRESTARTBLOCK_TRAMP]; 312 313 if (err) 314 return -EFAULT; 315 316 haddr = A(ksig->ka.sa.sa_handler); 317 /* The sa_handler may be a pointer to a function descriptor */ 318 #ifdef CONFIG_64BIT 319 if (is_compat_task()) { 320 #endif 321 if (haddr & PA_PLABEL_FDESC) { 322 Elf32_Fdesc fdesc; 323 Elf32_Fdesc __user *ufdesc = (Elf32_Fdesc __user *)A(haddr & ~3); 324 325 err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc)); 326 327 if (err) 328 return -EFAULT; 329 330 haddr = fdesc.addr; 331 regs->gr[19] = fdesc.gp; 332 } 333 #ifdef CONFIG_64BIT 334 } else { 335 Elf64_Fdesc fdesc; 336 Elf64_Fdesc __user *ufdesc = (Elf64_Fdesc __user *)A(haddr & ~3); 337 338 err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc)); 339 340 if (err) 341 return -EFAULT; 342 343 haddr = fdesc.addr; 344 regs->gr[19] = fdesc.gp; 345 DBG(1,"setup_rt_frame: 64 bit signal, exe=%#lx, r19=%#lx, in_syscall=%d\n", 346 haddr, regs->gr[19], in_syscall); 347 } 348 #endif 349 350 /* The syscall return path will create IAOQ values from r31. 351 */ 352 sigframe_size = PARISC_RT_SIGFRAME_SIZE; 353 #ifdef CONFIG_64BIT 354 if (is_compat_task()) 355 sigframe_size = PARISC_RT_SIGFRAME_SIZE32; 356 #endif 357 if (in_syscall) { 358 regs->gr[31] = haddr; 359 #ifdef CONFIG_64BIT 360 if (!test_thread_flag(TIF_32BIT)) 361 sigframe_size |= 1; 362 #endif 363 } else { 364 unsigned long psw = USER_PSW; 365 #ifdef CONFIG_64BIT 366 if (!test_thread_flag(TIF_32BIT)) 367 psw |= PSW_W; 368 #endif 369 370 /* If we are singlestepping, arrange a trap to be delivered 371 when we return to userspace. Note the semantics -- we 372 should trap before the first insn in the handler is 373 executed. Ref: 374 http://sources.redhat.com/ml/gdb/2004-11/msg00245.html 375 */ 376 if (pa_psw(current)->r) { 377 pa_psw(current)->r = 0; 378 psw |= PSW_R; 379 mtctl(-1, 0); 380 } 381 382 regs->gr[0] = psw; 383 regs->iaoq[0] = haddr | 3; 384 regs->iaoq[1] = regs->iaoq[0] + 4; 385 } 386 387 regs->gr[2] = rp; /* userland return pointer */ 388 regs->gr[26] = ksig->sig; /* signal number */ 389 390 #ifdef CONFIG_64BIT 391 if (is_compat_task()) { 392 regs->gr[25] = A(&compat_frame->info); /* siginfo pointer */ 393 regs->gr[24] = A(&compat_frame->uc); /* ucontext pointer */ 394 } else 395 #endif 396 { 397 regs->gr[25] = A(&frame->info); /* siginfo pointer */ 398 regs->gr[24] = A(&frame->uc); /* ucontext pointer */ 399 } 400 401 DBG(1,"setup_rt_frame: making sigreturn frame: %#lx + %#lx = %#lx\n", 402 regs->gr[30], sigframe_size, 403 regs->gr[30] + sigframe_size); 404 /* Raise the user stack pointer to make a proper call frame. */ 405 regs->gr[30] = (A(frame) + sigframe_size); 406 407 408 DBG(1,"setup_rt_frame: sig deliver (%s,%d) frame=0x%p sp=%#lx iaoq=%#lx/%#lx rp=%#lx\n", 409 current->comm, current->pid, frame, regs->gr[30], 410 regs->iaoq[0], regs->iaoq[1], rp); 411 412 return 0; 413 } 414 415 /* 416 * OK, we're invoking a handler. 417 */ 418 419 static void 420 handle_signal(struct ksignal *ksig, struct pt_regs *regs, int in_syscall) 421 { 422 int ret; 423 sigset_t *oldset = sigmask_to_save(); 424 425 DBG(1,"handle_signal: sig=%ld, ka=%p, info=%p, oldset=%p, regs=%p\n", 426 ksig->sig, ksig->ka, ksig->info, oldset, regs); 427 428 /* Set up the stack frame */ 429 ret = setup_rt_frame(ksig, oldset, regs, in_syscall); 430 431 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP) || 432 test_thread_flag(TIF_BLOCKSTEP)); 433 434 DBG(1,KERN_DEBUG "do_signal: Exit (success), regs->gr[28] = %ld\n", 435 regs->gr[28]); 436 } 437 438 static inline void 439 syscall_restart(struct pt_regs *regs, struct k_sigaction *ka) 440 { 441 if (regs->orig_r28) 442 return; 443 regs->orig_r28 = 1; /* no more restarts */ 444 /* Check the return code */ 445 switch (regs->gr[28]) { 446 case -ERESTART_RESTARTBLOCK: 447 case -ERESTARTNOHAND: 448 DBG(1,"ERESTARTNOHAND: returning -EINTR\n"); 449 regs->gr[28] = -EINTR; 450 break; 451 452 case -ERESTARTSYS: 453 if (!(ka->sa.sa_flags & SA_RESTART)) { 454 DBG(1,"ERESTARTSYS: putting -EINTR\n"); 455 regs->gr[28] = -EINTR; 456 break; 457 } 458 /* fallthrough */ 459 case -ERESTARTNOINTR: 460 /* A syscall is just a branch, so all 461 * we have to do is fiddle the return pointer. 462 */ 463 regs->gr[31] -= 8; /* delayed branching */ 464 break; 465 } 466 } 467 468 static inline void 469 insert_restart_trampoline(struct pt_regs *regs) 470 { 471 if (regs->orig_r28) 472 return; 473 regs->orig_r28 = 1; /* no more restarts */ 474 switch(regs->gr[28]) { 475 case -ERESTART_RESTARTBLOCK: { 476 /* Restart the system call - no handlers present */ 477 unsigned int *usp = (unsigned int *)regs->gr[30]; 478 unsigned long start = (unsigned long) &usp[2]; 479 unsigned long end = (unsigned long) &usp[5]; 480 long err = 0; 481 482 /* Setup a trampoline to restart the syscall 483 * with __NR_restart_syscall 484 * 485 * 0: <return address (orig r31)> 486 * 4: <2nd half for 64-bit> 487 * 8: ldw 0(%sp), %r31 488 * 12: be 0x100(%sr2, %r0) 489 * 16: ldi __NR_restart_syscall, %r20 490 */ 491 #ifdef CONFIG_64BIT 492 err |= put_user(regs->gr[31] >> 32, &usp[0]); 493 err |= put_user(regs->gr[31] & 0xffffffff, &usp[1]); 494 err |= put_user(0x0fc010df, &usp[2]); 495 #else 496 err |= put_user(regs->gr[31], &usp[0]); 497 err |= put_user(0x0fc0109f, &usp[2]); 498 #endif 499 err |= put_user(0xe0008200, &usp[3]); 500 err |= put_user(0x34140000, &usp[4]); 501 502 WARN_ON(err); 503 504 /* flush data/instruction cache for new insns */ 505 flush_user_dcache_range(start, end); 506 flush_user_icache_range(start, end); 507 508 regs->gr[31] = regs->gr[30] + 8; 509 return; 510 } 511 case -ERESTARTNOHAND: 512 case -ERESTARTSYS: 513 case -ERESTARTNOINTR: { 514 /* Hooray for delayed branching. We don't 515 * have to restore %r20 (the system call 516 * number) because it gets loaded in the delay 517 * slot of the branch external instruction. 518 */ 519 regs->gr[31] -= 8; 520 return; 521 } 522 default: 523 break; 524 } 525 } 526 527 /* 528 * Note that 'init' is a special process: it doesn't get signals it doesn't 529 * want to handle. Thus you cannot kill init even with a SIGKILL even by 530 * mistake. 531 * 532 * We need to be able to restore the syscall arguments (r21-r26) to 533 * restart syscalls. Thus, the syscall path should save them in the 534 * pt_regs structure (it's okay to do so since they are caller-save 535 * registers). As noted below, the syscall number gets restored for 536 * us due to the magic of delayed branching. 537 */ 538 asmlinkage void 539 do_signal(struct pt_regs *regs, long in_syscall) 540 { 541 struct ksignal ksig; 542 543 DBG(1,"\ndo_signal: regs=0x%p, sr7 %#lx, in_syscall=%d\n", 544 regs, regs->sr[7], in_syscall); 545 546 if (get_signal(&ksig)) { 547 DBG(3,"do_signal: signr = %d, regs->gr[28] = %ld\n", signr, regs->gr[28]); 548 /* Restart a system call if necessary. */ 549 if (in_syscall) 550 syscall_restart(regs, &ksig.ka); 551 552 handle_signal(&ksig, regs, in_syscall); 553 return; 554 } 555 556 /* Did we come from a system call? */ 557 if (in_syscall) 558 insert_restart_trampoline(regs); 559 560 DBG(1,"do_signal: Exit (not delivered), regs->gr[28] = %ld\n", 561 regs->gr[28]); 562 563 restore_saved_sigmask(); 564 } 565 566 void do_notify_resume(struct pt_regs *regs, long in_syscall) 567 { 568 if (test_thread_flag(TIF_SIGPENDING)) 569 do_signal(regs, in_syscall); 570 571 if (test_thread_flag(TIF_NOTIFY_RESUME)) { 572 clear_thread_flag(TIF_NOTIFY_RESUME); 573 tracehook_notify_resume(regs); 574 } 575 } 576