1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * arch/sparc64/kernel/signal.c 4 * 5 * Copyright (C) 1991, 1992 Linus Torvalds 6 * Copyright (C) 1995, 2008 David S. Miller (davem@davemloft.net) 7 * Copyright (C) 1996 Miguel de Icaza (miguel@nuclecu.unam.mx) 8 * Copyright (C) 1997 Eddie C. Dost (ecd@skynet.be) 9 * Copyright (C) 1997,1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz) 10 */ 11 12 #include <linux/sched.h> 13 #include <linux/kernel.h> 14 #include <linux/signal.h> 15 #include <linux/errno.h> 16 #include <linux/wait.h> 17 #include <linux/ptrace.h> 18 #include <linux/tracehook.h> 19 #include <linux/unistd.h> 20 #include <linux/mm.h> 21 #include <linux/tty.h> 22 #include <linux/binfmts.h> 23 #include <linux/bitops.h> 24 #include <linux/context_tracking.h> 25 26 #include <linux/uaccess.h> 27 #include <asm/ptrace.h> 28 #include <asm/pgtable.h> 29 #include <asm/fpumacro.h> 30 #include <asm/uctx.h> 31 #include <asm/siginfo.h> 32 #include <asm/visasm.h> 33 #include <asm/switch_to.h> 34 #include <asm/cacheflush.h> 35 36 #include "sigutil.h" 37 #include "systbls.h" 38 #include "kernel.h" 39 #include "entry.h" 40 41 /* {set, get}context() needed for 64-bit SparcLinux userland. */ 42 asmlinkage void sparc64_set_context(struct pt_regs *regs) 43 { 44 struct ucontext __user *ucp = (struct ucontext __user *) 45 regs->u_regs[UREG_I0]; 46 enum ctx_state prev_state = exception_enter(); 47 mc_gregset_t __user *grp; 48 unsigned long pc, npc, tstate; 49 unsigned long fp, i7; 50 unsigned char fenab; 51 int err; 52 53 synchronize_user_stack(); 54 if (get_thread_wsaved() || 55 (((unsigned long)ucp) & (sizeof(unsigned long)-1)) || 56 (!__access_ok(ucp, sizeof(*ucp)))) 57 goto do_sigsegv; 58 grp = &ucp->uc_mcontext.mc_gregs; 59 err = __get_user(pc, &((*grp)[MC_PC])); 60 err |= __get_user(npc, &((*grp)[MC_NPC])); 61 if (err || ((pc | npc) & 3)) 62 goto do_sigsegv; 63 if (regs->u_regs[UREG_I1]) { 64 sigset_t set; 65 66 if (_NSIG_WORDS == 1) { 67 if (__get_user(set.sig[0], &ucp->uc_sigmask.sig[0])) 68 goto do_sigsegv; 69 } else { 70 if (__copy_from_user(&set, &ucp->uc_sigmask, sizeof(sigset_t))) 71 goto do_sigsegv; 72 } 73 set_current_blocked(&set); 74 } 75 if (test_thread_flag(TIF_32BIT)) { 76 pc &= 0xffffffff; 77 npc &= 0xffffffff; 78 } 79 regs->tpc = pc; 80 regs->tnpc = npc; 81 err |= __get_user(regs->y, &((*grp)[MC_Y])); 82 err |= __get_user(tstate, &((*grp)[MC_TSTATE])); 83 regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC); 84 regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC)); 85 err |= __get_user(regs->u_regs[UREG_G1], (&(*grp)[MC_G1])); 86 err |= __get_user(regs->u_regs[UREG_G2], (&(*grp)[MC_G2])); 87 err |= __get_user(regs->u_regs[UREG_G3], (&(*grp)[MC_G3])); 88 err |= __get_user(regs->u_regs[UREG_G4], (&(*grp)[MC_G4])); 89 err |= __get_user(regs->u_regs[UREG_G5], (&(*grp)[MC_G5])); 90 err |= __get_user(regs->u_regs[UREG_G6], (&(*grp)[MC_G6])); 91 92 /* Skip %g7 as that's the thread register in userspace. */ 93 94 err |= __get_user(regs->u_regs[UREG_I0], (&(*grp)[MC_O0])); 95 err |= __get_user(regs->u_regs[UREG_I1], (&(*grp)[MC_O1])); 96 err |= __get_user(regs->u_regs[UREG_I2], (&(*grp)[MC_O2])); 97 err |= __get_user(regs->u_regs[UREG_I3], (&(*grp)[MC_O3])); 98 err |= __get_user(regs->u_regs[UREG_I4], (&(*grp)[MC_O4])); 99 err |= __get_user(regs->u_regs[UREG_I5], (&(*grp)[MC_O5])); 100 err |= __get_user(regs->u_regs[UREG_I6], (&(*grp)[MC_O6])); 101 err |= __get_user(regs->u_regs[UREG_I7], (&(*grp)[MC_O7])); 102 103 err |= __get_user(fp, &(ucp->uc_mcontext.mc_fp)); 104 err |= __get_user(i7, &(ucp->uc_mcontext.mc_i7)); 105 err |= __put_user(fp, 106 (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[6]))); 107 err |= __put_user(i7, 108 (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[7]))); 109 110 err |= __get_user(fenab, &(ucp->uc_mcontext.mc_fpregs.mcfpu_enab)); 111 if (fenab) { 112 unsigned long *fpregs = current_thread_info()->fpregs; 113 unsigned long fprs; 114 115 fprs_write(0); 116 err |= __get_user(fprs, &(ucp->uc_mcontext.mc_fpregs.mcfpu_fprs)); 117 if (fprs & FPRS_DL) 118 err |= copy_from_user(fpregs, 119 &(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs), 120 (sizeof(unsigned int) * 32)); 121 if (fprs & FPRS_DU) 122 err |= copy_from_user(fpregs+16, 123 ((unsigned long __user *)&(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs))+16, 124 (sizeof(unsigned int) * 32)); 125 err |= __get_user(current_thread_info()->xfsr[0], 126 &(ucp->uc_mcontext.mc_fpregs.mcfpu_fsr)); 127 err |= __get_user(current_thread_info()->gsr[0], 128 &(ucp->uc_mcontext.mc_fpregs.mcfpu_gsr)); 129 regs->tstate &= ~TSTATE_PEF; 130 } 131 if (err) 132 goto do_sigsegv; 133 out: 134 exception_exit(prev_state); 135 return; 136 do_sigsegv: 137 force_sig(SIGSEGV, current); 138 goto out; 139 } 140 141 asmlinkage void sparc64_get_context(struct pt_regs *regs) 142 { 143 struct ucontext __user *ucp = (struct ucontext __user *) 144 regs->u_regs[UREG_I0]; 145 enum ctx_state prev_state = exception_enter(); 146 mc_gregset_t __user *grp; 147 mcontext_t __user *mcp; 148 unsigned long fp, i7; 149 unsigned char fenab; 150 int err; 151 152 synchronize_user_stack(); 153 if (get_thread_wsaved() || clear_user(ucp, sizeof(*ucp))) 154 goto do_sigsegv; 155 156 #if 1 157 fenab = 0; /* IMO get_context is like any other system call, thus modifies FPU state -jj */ 158 #else 159 fenab = (current_thread_info()->fpsaved[0] & FPRS_FEF); 160 #endif 161 162 mcp = &ucp->uc_mcontext; 163 grp = &mcp->mc_gregs; 164 165 /* Skip over the trap instruction, first. */ 166 if (test_thread_flag(TIF_32BIT)) { 167 regs->tpc = (regs->tnpc & 0xffffffff); 168 regs->tnpc = (regs->tnpc + 4) & 0xffffffff; 169 } else { 170 regs->tpc = regs->tnpc; 171 regs->tnpc += 4; 172 } 173 err = 0; 174 if (_NSIG_WORDS == 1) 175 err |= __put_user(current->blocked.sig[0], 176 (unsigned long __user *)&ucp->uc_sigmask); 177 else 178 err |= __copy_to_user(&ucp->uc_sigmask, ¤t->blocked, 179 sizeof(sigset_t)); 180 181 err |= __put_user(regs->tstate, &((*grp)[MC_TSTATE])); 182 err |= __put_user(regs->tpc, &((*grp)[MC_PC])); 183 err |= __put_user(regs->tnpc, &((*grp)[MC_NPC])); 184 err |= __put_user(regs->y, &((*grp)[MC_Y])); 185 err |= __put_user(regs->u_regs[UREG_G1], &((*grp)[MC_G1])); 186 err |= __put_user(regs->u_regs[UREG_G2], &((*grp)[MC_G2])); 187 err |= __put_user(regs->u_regs[UREG_G3], &((*grp)[MC_G3])); 188 err |= __put_user(regs->u_regs[UREG_G4], &((*grp)[MC_G4])); 189 err |= __put_user(regs->u_regs[UREG_G5], &((*grp)[MC_G5])); 190 err |= __put_user(regs->u_regs[UREG_G6], &((*grp)[MC_G6])); 191 err |= __put_user(regs->u_regs[UREG_G7], &((*grp)[MC_G7])); 192 err |= __put_user(regs->u_regs[UREG_I0], &((*grp)[MC_O0])); 193 err |= __put_user(regs->u_regs[UREG_I1], &((*grp)[MC_O1])); 194 err |= __put_user(regs->u_regs[UREG_I2], &((*grp)[MC_O2])); 195 err |= __put_user(regs->u_regs[UREG_I3], &((*grp)[MC_O3])); 196 err |= __put_user(regs->u_regs[UREG_I4], &((*grp)[MC_O4])); 197 err |= __put_user(regs->u_regs[UREG_I5], &((*grp)[MC_O5])); 198 err |= __put_user(regs->u_regs[UREG_I6], &((*grp)[MC_O6])); 199 err |= __put_user(regs->u_regs[UREG_I7], &((*grp)[MC_O7])); 200 201 err |= __get_user(fp, 202 (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[6]))); 203 err |= __get_user(i7, 204 (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[7]))); 205 err |= __put_user(fp, &(mcp->mc_fp)); 206 err |= __put_user(i7, &(mcp->mc_i7)); 207 208 err |= __put_user(fenab, &(mcp->mc_fpregs.mcfpu_enab)); 209 if (fenab) { 210 unsigned long *fpregs = current_thread_info()->fpregs; 211 unsigned long fprs; 212 213 fprs = current_thread_info()->fpsaved[0]; 214 if (fprs & FPRS_DL) 215 err |= copy_to_user(&(mcp->mc_fpregs.mcfpu_fregs), fpregs, 216 (sizeof(unsigned int) * 32)); 217 if (fprs & FPRS_DU) 218 err |= copy_to_user( 219 ((unsigned long __user *)&(mcp->mc_fpregs.mcfpu_fregs))+16, fpregs+16, 220 (sizeof(unsigned int) * 32)); 221 err |= __put_user(current_thread_info()->xfsr[0], &(mcp->mc_fpregs.mcfpu_fsr)); 222 err |= __put_user(current_thread_info()->gsr[0], &(mcp->mc_fpregs.mcfpu_gsr)); 223 err |= __put_user(fprs, &(mcp->mc_fpregs.mcfpu_fprs)); 224 } 225 if (err) 226 goto do_sigsegv; 227 out: 228 exception_exit(prev_state); 229 return; 230 do_sigsegv: 231 force_sig(SIGSEGV, current); 232 goto out; 233 } 234 235 /* Checks if the fp is valid. We always build rt signal frames which 236 * are 16-byte aligned, therefore we can always enforce that the 237 * restore frame has that property as well. 238 */ 239 static bool invalid_frame_pointer(void __user *fp) 240 { 241 if (((unsigned long) fp) & 15) 242 return true; 243 return false; 244 } 245 246 struct rt_signal_frame { 247 struct sparc_stackf ss; 248 siginfo_t info; 249 struct pt_regs regs; 250 __siginfo_fpu_t __user *fpu_save; 251 stack_t stack; 252 sigset_t mask; 253 __siginfo_rwin_t *rwin_save; 254 }; 255 256 void do_rt_sigreturn(struct pt_regs *regs) 257 { 258 unsigned long tpc, tnpc, tstate, ufp; 259 struct rt_signal_frame __user *sf; 260 __siginfo_fpu_t __user *fpu_save; 261 __siginfo_rwin_t __user *rwin_save; 262 sigset_t set; 263 int err; 264 265 /* Always make any pending restarted system calls return -EINTR */ 266 current->restart_block.fn = do_no_restart_syscall; 267 268 synchronize_user_stack (); 269 sf = (struct rt_signal_frame __user *) 270 (regs->u_regs [UREG_FP] + STACK_BIAS); 271 272 /* 1. Make sure we are not getting garbage from the user */ 273 if (invalid_frame_pointer(sf)) 274 goto segv; 275 276 if (get_user(ufp, &sf->regs.u_regs[UREG_FP])) 277 goto segv; 278 279 if ((ufp + STACK_BIAS) & 0x7) 280 goto segv; 281 282 err = __get_user(tpc, &sf->regs.tpc); 283 err |= __get_user(tnpc, &sf->regs.tnpc); 284 if (test_thread_flag(TIF_32BIT)) { 285 tpc &= 0xffffffff; 286 tnpc &= 0xffffffff; 287 } 288 err |= ((tpc | tnpc) & 3); 289 290 /* 2. Restore the state */ 291 err |= __get_user(regs->y, &sf->regs.y); 292 err |= __get_user(tstate, &sf->regs.tstate); 293 err |= copy_from_user(regs->u_regs, sf->regs.u_regs, sizeof(regs->u_regs)); 294 295 /* User can only change condition codes and %asi in %tstate. */ 296 regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC); 297 regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC)); 298 299 err |= __get_user(fpu_save, &sf->fpu_save); 300 if (!err && fpu_save) 301 err |= restore_fpu_state(regs, fpu_save); 302 303 err |= __copy_from_user(&set, &sf->mask, sizeof(sigset_t)); 304 err |= restore_altstack(&sf->stack); 305 if (err) 306 goto segv; 307 308 err |= __get_user(rwin_save, &sf->rwin_save); 309 if (!err && rwin_save) { 310 if (restore_rwin_state(rwin_save)) 311 goto segv; 312 } 313 314 regs->tpc = tpc; 315 regs->tnpc = tnpc; 316 317 /* Prevent syscall restart. */ 318 pt_regs_clear_syscall(regs); 319 320 set_current_blocked(&set); 321 return; 322 segv: 323 force_sig(SIGSEGV, current); 324 } 325 326 static inline void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, unsigned long framesize) 327 { 328 unsigned long sp = regs->u_regs[UREG_FP] + STACK_BIAS; 329 330 /* 331 * If we are on the alternate signal stack and would overflow it, don't. 332 * Return an always-bogus address instead so we will die with SIGSEGV. 333 */ 334 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize))) 335 return (void __user *) -1L; 336 337 /* This is the X/Open sanctioned signal stack switching. */ 338 sp = sigsp(sp, ksig) - framesize; 339 340 /* Always align the stack frame. This handles two cases. First, 341 * sigaltstack need not be mindful of platform specific stack 342 * alignment. Second, if we took this signal because the stack 343 * is not aligned properly, we'd like to take the signal cleanly 344 * and report that. 345 */ 346 sp &= ~15UL; 347 348 return (void __user *) sp; 349 } 350 351 static inline int 352 setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) 353 { 354 struct rt_signal_frame __user *sf; 355 int wsaved, err, sf_size; 356 void __user *tail; 357 358 /* 1. Make sure everything is clean */ 359 synchronize_user_stack(); 360 save_and_clear_fpu(); 361 362 wsaved = get_thread_wsaved(); 363 364 sf_size = sizeof(struct rt_signal_frame); 365 if (current_thread_info()->fpsaved[0] & FPRS_FEF) 366 sf_size += sizeof(__siginfo_fpu_t); 367 if (wsaved) 368 sf_size += sizeof(__siginfo_rwin_t); 369 sf = (struct rt_signal_frame __user *) 370 get_sigframe(ksig, regs, sf_size); 371 372 if (invalid_frame_pointer (sf)) { 373 if (show_unhandled_signals) 374 pr_info("%s[%d] bad frame in setup_rt_frame: %016lx TPC %016lx O7 %016lx\n", 375 current->comm, current->pid, (unsigned long)sf, 376 regs->tpc, regs->u_regs[UREG_I7]); 377 force_sigsegv(ksig->sig, current); 378 return -EINVAL; 379 } 380 381 tail = (sf + 1); 382 383 /* 2. Save the current process state */ 384 err = copy_to_user(&sf->regs, regs, sizeof (*regs)); 385 386 if (current_thread_info()->fpsaved[0] & FPRS_FEF) { 387 __siginfo_fpu_t __user *fpu_save = tail; 388 tail += sizeof(__siginfo_fpu_t); 389 err |= save_fpu_state(regs, fpu_save); 390 err |= __put_user((u64)fpu_save, &sf->fpu_save); 391 } else { 392 err |= __put_user(0, &sf->fpu_save); 393 } 394 if (wsaved) { 395 __siginfo_rwin_t __user *rwin_save = tail; 396 tail += sizeof(__siginfo_rwin_t); 397 err |= save_rwin_state(wsaved, rwin_save); 398 err |= __put_user((u64)rwin_save, &sf->rwin_save); 399 set_thread_wsaved(0); 400 } else { 401 err |= __put_user(0, &sf->rwin_save); 402 } 403 404 /* Setup sigaltstack */ 405 err |= __save_altstack(&sf->stack, regs->u_regs[UREG_FP]); 406 407 err |= copy_to_user(&sf->mask, sigmask_to_save(), sizeof(sigset_t)); 408 409 if (!wsaved) { 410 err |= copy_in_user((u64 __user *)sf, 411 (u64 __user *)(regs->u_regs[UREG_FP] + 412 STACK_BIAS), 413 sizeof(struct reg_window)); 414 } else { 415 struct reg_window *rp; 416 417 rp = ¤t_thread_info()->reg_window[wsaved - 1]; 418 err |= copy_to_user(sf, rp, sizeof(struct reg_window)); 419 } 420 if (ksig->ka.sa.sa_flags & SA_SIGINFO) 421 err |= copy_siginfo_to_user(&sf->info, &ksig->info); 422 else { 423 err |= __put_user(ksig->sig, &sf->info.si_signo); 424 err |= __put_user(SI_NOINFO, &sf->info.si_code); 425 } 426 if (err) 427 return err; 428 429 /* 3. signal handler back-trampoline and parameters */ 430 regs->u_regs[UREG_FP] = ((unsigned long) sf) - STACK_BIAS; 431 regs->u_regs[UREG_I0] = ksig->sig; 432 regs->u_regs[UREG_I1] = (unsigned long) &sf->info; 433 434 /* The sigcontext is passed in this way because of how it 435 * is defined in GLIBC's /usr/include/bits/sigcontext.h 436 * for sparc64. It includes the 128 bytes of siginfo_t. 437 */ 438 regs->u_regs[UREG_I2] = (unsigned long) &sf->info; 439 440 /* 5. signal handler */ 441 regs->tpc = (unsigned long) ksig->ka.sa.sa_handler; 442 regs->tnpc = (regs->tpc + 4); 443 if (test_thread_flag(TIF_32BIT)) { 444 regs->tpc &= 0xffffffff; 445 regs->tnpc &= 0xffffffff; 446 } 447 /* 4. return to kernel instructions */ 448 regs->u_regs[UREG_I7] = (unsigned long)ksig->ka.ka_restorer; 449 return 0; 450 } 451 452 static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs, 453 struct sigaction *sa) 454 { 455 switch (regs->u_regs[UREG_I0]) { 456 case ERESTART_RESTARTBLOCK: 457 case ERESTARTNOHAND: 458 no_system_call_restart: 459 regs->u_regs[UREG_I0] = EINTR; 460 regs->tstate |= (TSTATE_ICARRY|TSTATE_XCARRY); 461 break; 462 case ERESTARTSYS: 463 if (!(sa->sa_flags & SA_RESTART)) 464 goto no_system_call_restart; 465 /* fallthrough */ 466 case ERESTARTNOINTR: 467 regs->u_regs[UREG_I0] = orig_i0; 468 regs->tpc -= 4; 469 regs->tnpc -= 4; 470 } 471 } 472 473 /* Note that 'init' is a special process: it doesn't get signals it doesn't 474 * want to handle. Thus you cannot kill init even with a SIGKILL even by 475 * mistake. 476 */ 477 static void do_signal(struct pt_regs *regs, unsigned long orig_i0) 478 { 479 struct ksignal ksig; 480 int restart_syscall; 481 bool has_handler; 482 483 /* It's a lot of work and synchronization to add a new ptrace 484 * register for GDB to save and restore in order to get 485 * orig_i0 correct for syscall restarts when debugging. 486 * 487 * Although it should be the case that most of the global 488 * registers are volatile across a system call, glibc already 489 * depends upon that fact that we preserve them. So we can't 490 * just use any global register to save away the orig_i0 value. 491 * 492 * In particular %g2, %g3, %g4, and %g5 are all assumed to be 493 * preserved across a system call trap by various pieces of 494 * code in glibc. 495 * 496 * %g7 is used as the "thread register". %g6 is not used in 497 * any fixed manner. %g6 is used as a scratch register and 498 * a compiler temporary, but it's value is never used across 499 * a system call. Therefore %g6 is usable for orig_i0 storage. 500 */ 501 if (pt_regs_is_syscall(regs) && 502 (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY))) 503 regs->u_regs[UREG_G6] = orig_i0; 504 505 #ifdef CONFIG_COMPAT 506 if (test_thread_flag(TIF_32BIT)) { 507 do_signal32(regs); 508 return; 509 } 510 #endif 511 512 has_handler = get_signal(&ksig); 513 514 restart_syscall = 0; 515 if (pt_regs_is_syscall(regs) && 516 (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY))) { 517 restart_syscall = 1; 518 orig_i0 = regs->u_regs[UREG_G6]; 519 } 520 521 if (has_handler) { 522 if (restart_syscall) 523 syscall_restart(orig_i0, regs, &ksig.ka.sa); 524 signal_setup_done(setup_rt_frame(&ksig, regs), &ksig, 0); 525 } else { 526 if (restart_syscall) { 527 switch (regs->u_regs[UREG_I0]) { 528 case ERESTARTNOHAND: 529 case ERESTARTSYS: 530 case ERESTARTNOINTR: 531 /* replay the system call when we are done */ 532 regs->u_regs[UREG_I0] = orig_i0; 533 regs->tpc -= 4; 534 regs->tnpc -= 4; 535 pt_regs_clear_syscall(regs); 536 /* fall through */ 537 case ERESTART_RESTARTBLOCK: 538 regs->u_regs[UREG_G1] = __NR_restart_syscall; 539 regs->tpc -= 4; 540 regs->tnpc -= 4; 541 pt_regs_clear_syscall(regs); 542 } 543 } 544 restore_saved_sigmask(); 545 } 546 } 547 548 void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, unsigned long thread_info_flags) 549 { 550 user_exit(); 551 if (thread_info_flags & _TIF_UPROBE) 552 uprobe_notify_resume(regs); 553 if (thread_info_flags & _TIF_SIGPENDING) 554 do_signal(regs, orig_i0); 555 if (thread_info_flags & _TIF_NOTIFY_RESUME) { 556 clear_thread_flag(TIF_NOTIFY_RESUME); 557 tracehook_notify_resume(regs); 558 } 559 user_enter(); 560 } 561 562