1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * PowerPC version 4 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) 5 * 6 * Derived from "arch/i386/kernel/signal.c" 7 * Copyright (C) 1991, 1992 Linus Torvalds 8 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson 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/unistd.h> 19 #include <linux/stddef.h> 20 #include <linux/elf.h> 21 #include <linux/ptrace.h> 22 #include <linux/ratelimit.h> 23 #include <linux/syscalls.h> 24 25 #include <asm/sigcontext.h> 26 #include <asm/ucontext.h> 27 #include <linux/uaccess.h> 28 #include <asm/pgtable.h> 29 #include <asm/unistd.h> 30 #include <asm/cacheflush.h> 31 #include <asm/syscalls.h> 32 #include <asm/vdso.h> 33 #include <asm/switch_to.h> 34 #include <asm/tm.h> 35 #include <asm/asm-prototypes.h> 36 37 #include "signal.h" 38 39 40 #define GP_REGS_SIZE min(sizeof(elf_gregset_t), sizeof(struct pt_regs)) 41 #define FP_REGS_SIZE sizeof(elf_fpregset_t) 42 43 #define TRAMP_TRACEBACK 3 44 #define TRAMP_SIZE 6 45 46 /* 47 * When we have signals to deliver, we set up on the user stack, 48 * going down from the original stack pointer: 49 * 1) a rt_sigframe struct which contains the ucontext 50 * 2) a gap of __SIGNAL_FRAMESIZE bytes which acts as a dummy caller 51 * frame for the signal handler. 52 */ 53 54 struct rt_sigframe { 55 /* sys_rt_sigreturn requires the ucontext be the first field */ 56 struct ucontext uc; 57 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM 58 struct ucontext uc_transact; 59 #endif 60 unsigned long _unused[2]; 61 unsigned int tramp[TRAMP_SIZE]; 62 struct siginfo __user *pinfo; 63 void __user *puc; 64 struct siginfo info; 65 /* New 64 bit little-endian ABI allows redzone of 512 bytes below sp */ 66 char abigap[USER_REDZONE_SIZE]; 67 } __attribute__ ((aligned (16))); 68 69 static const char fmt32[] = KERN_INFO \ 70 "%s[%d]: bad frame in %s: %08lx nip %08lx lr %08lx\n"; 71 static const char fmt64[] = KERN_INFO \ 72 "%s[%d]: bad frame in %s: %016lx nip %016lx lr %016lx\n"; 73 74 /* 75 * This computes a quad word aligned pointer inside the vmx_reserve array 76 * element. For historical reasons sigcontext might not be quad word aligned, 77 * but the location we write the VMX regs to must be. See the comment in 78 * sigcontext for more detail. 79 */ 80 #ifdef CONFIG_ALTIVEC 81 static elf_vrreg_t __user *sigcontext_vmx_regs(struct sigcontext __user *sc) 82 { 83 return (elf_vrreg_t __user *) (((unsigned long)sc->vmx_reserve + 15) & ~0xful); 84 } 85 #endif 86 87 /* 88 * Set up the sigcontext for the signal frame. 89 */ 90 91 static long setup_sigcontext(struct sigcontext __user *sc, 92 struct task_struct *tsk, int signr, sigset_t *set, 93 unsigned long handler, int ctx_has_vsx_region) 94 { 95 /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the 96 * process never used altivec yet (MSR_VEC is zero in pt_regs of 97 * the context). This is very important because we must ensure we 98 * don't lose the VRSAVE content that may have been set prior to 99 * the process doing its first vector operation 100 * Userland shall check AT_HWCAP to know whether it can rely on the 101 * v_regs pointer or not 102 */ 103 #ifdef CONFIG_ALTIVEC 104 elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc); 105 unsigned long vrsave; 106 #endif 107 struct pt_regs *regs = tsk->thread.regs; 108 unsigned long msr = regs->msr; 109 long err = 0; 110 /* Force usr to alway see softe as 1 (interrupts enabled) */ 111 unsigned long softe = 0x1; 112 113 BUG_ON(tsk != current); 114 115 #ifdef CONFIG_ALTIVEC 116 err |= __put_user(v_regs, &sc->v_regs); 117 118 /* save altivec registers */ 119 if (tsk->thread.used_vr) { 120 flush_altivec_to_thread(tsk); 121 /* Copy 33 vec registers (vr0..31 and vscr) to the stack */ 122 err |= __copy_to_user(v_regs, &tsk->thread.vr_state, 123 33 * sizeof(vector128)); 124 /* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg) 125 * contains valid data. 126 */ 127 msr |= MSR_VEC; 128 } 129 /* We always copy to/from vrsave, it's 0 if we don't have or don't 130 * use altivec. 131 */ 132 vrsave = 0; 133 if (cpu_has_feature(CPU_FTR_ALTIVEC)) { 134 vrsave = mfspr(SPRN_VRSAVE); 135 tsk->thread.vrsave = vrsave; 136 } 137 138 err |= __put_user(vrsave, (u32 __user *)&v_regs[33]); 139 #else /* CONFIG_ALTIVEC */ 140 err |= __put_user(0, &sc->v_regs); 141 #endif /* CONFIG_ALTIVEC */ 142 flush_fp_to_thread(tsk); 143 /* copy fpr regs and fpscr */ 144 err |= copy_fpr_to_user(&sc->fp_regs, tsk); 145 146 /* 147 * Clear the MSR VSX bit to indicate there is no valid state attached 148 * to this context, except in the specific case below where we set it. 149 */ 150 msr &= ~MSR_VSX; 151 #ifdef CONFIG_VSX 152 /* 153 * Copy VSX low doubleword to local buffer for formatting, 154 * then out to userspace. Update v_regs to point after the 155 * VMX data. 156 */ 157 if (tsk->thread.used_vsr && ctx_has_vsx_region) { 158 flush_vsx_to_thread(tsk); 159 v_regs += ELF_NVRREG; 160 err |= copy_vsx_to_user(v_regs, tsk); 161 /* set MSR_VSX in the MSR value in the frame to 162 * indicate that sc->vs_reg) contains valid data. 163 */ 164 msr |= MSR_VSX; 165 } 166 #endif /* CONFIG_VSX */ 167 err |= __put_user(&sc->gp_regs, &sc->regs); 168 WARN_ON(!FULL_REGS(regs)); 169 err |= __copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE); 170 err |= __put_user(msr, &sc->gp_regs[PT_MSR]); 171 err |= __put_user(softe, &sc->gp_regs[PT_SOFTE]); 172 err |= __put_user(signr, &sc->signal); 173 err |= __put_user(handler, &sc->handler); 174 if (set != NULL) 175 err |= __put_user(set->sig[0], &sc->oldmask); 176 177 return err; 178 } 179 180 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM 181 /* 182 * As above, but Transactional Memory is in use, so deliver sigcontexts 183 * containing checkpointed and transactional register states. 184 * 185 * To do this, we treclaim (done before entering here) to gather both sets of 186 * registers and set up the 'normal' sigcontext registers with rolled-back 187 * register values such that a simple signal handler sees a correct 188 * checkpointed register state. If interested, a TM-aware sighandler can 189 * examine the transactional registers in the 2nd sigcontext to determine the 190 * real origin of the signal. 191 */ 192 static long setup_tm_sigcontexts(struct sigcontext __user *sc, 193 struct sigcontext __user *tm_sc, 194 struct task_struct *tsk, 195 int signr, sigset_t *set, unsigned long handler) 196 { 197 /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the 198 * process never used altivec yet (MSR_VEC is zero in pt_regs of 199 * the context). This is very important because we must ensure we 200 * don't lose the VRSAVE content that may have been set prior to 201 * the process doing its first vector operation 202 * Userland shall check AT_HWCAP to know wether it can rely on the 203 * v_regs pointer or not. 204 */ 205 #ifdef CONFIG_ALTIVEC 206 elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc); 207 elf_vrreg_t __user *tm_v_regs = sigcontext_vmx_regs(tm_sc); 208 #endif 209 struct pt_regs *regs = tsk->thread.regs; 210 unsigned long msr = tsk->thread.regs->msr; 211 long err = 0; 212 213 BUG_ON(tsk != current); 214 215 BUG_ON(!MSR_TM_ACTIVE(regs->msr)); 216 217 WARN_ON(tm_suspend_disabled); 218 219 /* Restore checkpointed FP, VEC, and VSX bits from ckpt_regs as 220 * it contains the correct FP, VEC, VSX state after we treclaimed 221 * the transaction and giveup_all() was called on reclaiming. 222 */ 223 msr |= tsk->thread.ckpt_regs.msr & (MSR_FP | MSR_VEC | MSR_VSX); 224 225 /* Remove TM bits from thread's MSR. The MSR in the sigcontext 226 * just indicates to userland that we were doing a transaction, but we 227 * don't want to return in transactional state. This also ensures 228 * that flush_fp_to_thread won't set TIF_RESTORE_TM again. 229 */ 230 regs->msr &= ~MSR_TS_MASK; 231 232 #ifdef CONFIG_ALTIVEC 233 err |= __put_user(v_regs, &sc->v_regs); 234 err |= __put_user(tm_v_regs, &tm_sc->v_regs); 235 236 /* save altivec registers */ 237 if (tsk->thread.used_vr) { 238 /* Copy 33 vec registers (vr0..31 and vscr) to the stack */ 239 err |= __copy_to_user(v_regs, &tsk->thread.ckvr_state, 240 33 * sizeof(vector128)); 241 /* If VEC was enabled there are transactional VRs valid too, 242 * else they're a copy of the checkpointed VRs. 243 */ 244 if (msr & MSR_VEC) 245 err |= __copy_to_user(tm_v_regs, 246 &tsk->thread.vr_state, 247 33 * sizeof(vector128)); 248 else 249 err |= __copy_to_user(tm_v_regs, 250 &tsk->thread.ckvr_state, 251 33 * sizeof(vector128)); 252 253 /* set MSR_VEC in the MSR value in the frame to indicate 254 * that sc->v_reg contains valid data. 255 */ 256 msr |= MSR_VEC; 257 } 258 /* We always copy to/from vrsave, it's 0 if we don't have or don't 259 * use altivec. 260 */ 261 if (cpu_has_feature(CPU_FTR_ALTIVEC)) 262 tsk->thread.ckvrsave = mfspr(SPRN_VRSAVE); 263 err |= __put_user(tsk->thread.ckvrsave, (u32 __user *)&v_regs[33]); 264 if (msr & MSR_VEC) 265 err |= __put_user(tsk->thread.vrsave, 266 (u32 __user *)&tm_v_regs[33]); 267 else 268 err |= __put_user(tsk->thread.ckvrsave, 269 (u32 __user *)&tm_v_regs[33]); 270 271 #else /* CONFIG_ALTIVEC */ 272 err |= __put_user(0, &sc->v_regs); 273 err |= __put_user(0, &tm_sc->v_regs); 274 #endif /* CONFIG_ALTIVEC */ 275 276 /* copy fpr regs and fpscr */ 277 err |= copy_ckfpr_to_user(&sc->fp_regs, tsk); 278 if (msr & MSR_FP) 279 err |= copy_fpr_to_user(&tm_sc->fp_regs, tsk); 280 else 281 err |= copy_ckfpr_to_user(&tm_sc->fp_regs, tsk); 282 283 #ifdef CONFIG_VSX 284 /* 285 * Copy VSX low doubleword to local buffer for formatting, 286 * then out to userspace. Update v_regs to point after the 287 * VMX data. 288 */ 289 if (tsk->thread.used_vsr) { 290 v_regs += ELF_NVRREG; 291 tm_v_regs += ELF_NVRREG; 292 293 err |= copy_ckvsx_to_user(v_regs, tsk); 294 295 if (msr & MSR_VSX) 296 err |= copy_vsx_to_user(tm_v_regs, tsk); 297 else 298 err |= copy_ckvsx_to_user(tm_v_regs, tsk); 299 300 /* set MSR_VSX in the MSR value in the frame to 301 * indicate that sc->vs_reg) contains valid data. 302 */ 303 msr |= MSR_VSX; 304 } 305 #endif /* CONFIG_VSX */ 306 307 err |= __put_user(&sc->gp_regs, &sc->regs); 308 err |= __put_user(&tm_sc->gp_regs, &tm_sc->regs); 309 WARN_ON(!FULL_REGS(regs)); 310 err |= __copy_to_user(&tm_sc->gp_regs, regs, GP_REGS_SIZE); 311 err |= __copy_to_user(&sc->gp_regs, 312 &tsk->thread.ckpt_regs, GP_REGS_SIZE); 313 err |= __put_user(msr, &tm_sc->gp_regs[PT_MSR]); 314 err |= __put_user(msr, &sc->gp_regs[PT_MSR]); 315 err |= __put_user(signr, &sc->signal); 316 err |= __put_user(handler, &sc->handler); 317 if (set != NULL) 318 err |= __put_user(set->sig[0], &sc->oldmask); 319 320 return err; 321 } 322 #endif 323 324 /* 325 * Restore the sigcontext from the signal frame. 326 */ 327 328 static long restore_sigcontext(struct task_struct *tsk, sigset_t *set, int sig, 329 struct sigcontext __user *sc) 330 { 331 #ifdef CONFIG_ALTIVEC 332 elf_vrreg_t __user *v_regs; 333 #endif 334 unsigned long err = 0; 335 unsigned long save_r13 = 0; 336 unsigned long msr; 337 struct pt_regs *regs = tsk->thread.regs; 338 #ifdef CONFIG_VSX 339 int i; 340 #endif 341 342 BUG_ON(tsk != current); 343 344 /* If this is not a signal return, we preserve the TLS in r13 */ 345 if (!sig) 346 save_r13 = regs->gpr[13]; 347 348 /* copy the GPRs */ 349 err |= __copy_from_user(regs->gpr, sc->gp_regs, sizeof(regs->gpr)); 350 err |= __get_user(regs->nip, &sc->gp_regs[PT_NIP]); 351 /* get MSR separately, transfer the LE bit if doing signal return */ 352 err |= __get_user(msr, &sc->gp_regs[PT_MSR]); 353 if (sig) 354 regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE); 355 err |= __get_user(regs->orig_gpr3, &sc->gp_regs[PT_ORIG_R3]); 356 err |= __get_user(regs->ctr, &sc->gp_regs[PT_CTR]); 357 err |= __get_user(regs->link, &sc->gp_regs[PT_LNK]); 358 err |= __get_user(regs->xer, &sc->gp_regs[PT_XER]); 359 err |= __get_user(regs->ccr, &sc->gp_regs[PT_CCR]); 360 /* skip SOFTE */ 361 regs->trap = 0; 362 err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]); 363 err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]); 364 err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]); 365 366 if (!sig) 367 regs->gpr[13] = save_r13; 368 if (set != NULL) 369 err |= __get_user(set->sig[0], &sc->oldmask); 370 371 /* 372 * Force reload of FP/VEC. 373 * This has to be done before copying stuff into tsk->thread.fpr/vr 374 * for the reasons explained in the previous comment. 375 */ 376 regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX); 377 378 #ifdef CONFIG_ALTIVEC 379 err |= __get_user(v_regs, &sc->v_regs); 380 if (err) 381 return err; 382 if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128))) 383 return -EFAULT; 384 /* Copy 33 vec registers (vr0..31 and vscr) from the stack */ 385 if (v_regs != NULL && (msr & MSR_VEC) != 0) { 386 err |= __copy_from_user(&tsk->thread.vr_state, v_regs, 387 33 * sizeof(vector128)); 388 tsk->thread.used_vr = true; 389 } else if (tsk->thread.used_vr) { 390 memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128)); 391 } 392 /* Always get VRSAVE back */ 393 if (v_regs != NULL) 394 err |= __get_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33]); 395 else 396 tsk->thread.vrsave = 0; 397 if (cpu_has_feature(CPU_FTR_ALTIVEC)) 398 mtspr(SPRN_VRSAVE, tsk->thread.vrsave); 399 #endif /* CONFIG_ALTIVEC */ 400 /* restore floating point */ 401 err |= copy_fpr_from_user(tsk, &sc->fp_regs); 402 #ifdef CONFIG_VSX 403 /* 404 * Get additional VSX data. Update v_regs to point after the 405 * VMX data. Copy VSX low doubleword from userspace to local 406 * buffer for formatting, then into the taskstruct. 407 */ 408 v_regs += ELF_NVRREG; 409 if ((msr & MSR_VSX) != 0) { 410 err |= copy_vsx_from_user(tsk, v_regs); 411 tsk->thread.used_vsr = true; 412 } else { 413 for (i = 0; i < 32 ; i++) 414 tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0; 415 } 416 #endif 417 return err; 418 } 419 420 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM 421 /* 422 * Restore the two sigcontexts from the frame of a transactional processes. 423 */ 424 425 static long restore_tm_sigcontexts(struct task_struct *tsk, 426 struct sigcontext __user *sc, 427 struct sigcontext __user *tm_sc) 428 { 429 #ifdef CONFIG_ALTIVEC 430 elf_vrreg_t __user *v_regs, *tm_v_regs; 431 #endif 432 unsigned long err = 0; 433 unsigned long msr; 434 struct pt_regs *regs = tsk->thread.regs; 435 #ifdef CONFIG_VSX 436 int i; 437 #endif 438 439 BUG_ON(tsk != current); 440 441 if (tm_suspend_disabled) 442 return -EINVAL; 443 444 /* copy the GPRs */ 445 err |= __copy_from_user(regs->gpr, tm_sc->gp_regs, sizeof(regs->gpr)); 446 err |= __copy_from_user(&tsk->thread.ckpt_regs, sc->gp_regs, 447 sizeof(regs->gpr)); 448 449 /* 450 * TFHAR is restored from the checkpointed 'wound-back' ucontext's NIP. 451 * TEXASR was set by the signal delivery reclaim, as was TFIAR. 452 * Users doing anything abhorrent like thread-switching w/ signals for 453 * TM-Suspended code will have to back TEXASR/TFIAR up themselves. 454 * For the case of getting a signal and simply returning from it, 455 * we don't need to re-copy them here. 456 */ 457 err |= __get_user(regs->nip, &tm_sc->gp_regs[PT_NIP]); 458 err |= __get_user(tsk->thread.tm_tfhar, &sc->gp_regs[PT_NIP]); 459 460 /* get MSR separately, transfer the LE bit if doing signal return */ 461 err |= __get_user(msr, &sc->gp_regs[PT_MSR]); 462 /* Don't allow reserved mode. */ 463 if (MSR_TM_RESV(msr)) 464 return -EINVAL; 465 466 /* pull in MSR LE from user context */ 467 regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE); 468 469 /* The following non-GPR non-FPR non-VR state is also checkpointed: */ 470 err |= __get_user(regs->ctr, &tm_sc->gp_regs[PT_CTR]); 471 err |= __get_user(regs->link, &tm_sc->gp_regs[PT_LNK]); 472 err |= __get_user(regs->xer, &tm_sc->gp_regs[PT_XER]); 473 err |= __get_user(regs->ccr, &tm_sc->gp_regs[PT_CCR]); 474 err |= __get_user(tsk->thread.ckpt_regs.ctr, 475 &sc->gp_regs[PT_CTR]); 476 err |= __get_user(tsk->thread.ckpt_regs.link, 477 &sc->gp_regs[PT_LNK]); 478 err |= __get_user(tsk->thread.ckpt_regs.xer, 479 &sc->gp_regs[PT_XER]); 480 err |= __get_user(tsk->thread.ckpt_regs.ccr, 481 &sc->gp_regs[PT_CCR]); 482 483 /* These regs are not checkpointed; they can go in 'regs'. */ 484 err |= __get_user(regs->trap, &sc->gp_regs[PT_TRAP]); 485 err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]); 486 err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]); 487 err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]); 488 489 /* 490 * Force reload of FP/VEC. 491 * This has to be done before copying stuff into tsk->thread.fpr/vr 492 * for the reasons explained in the previous comment. 493 */ 494 regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX); 495 496 #ifdef CONFIG_ALTIVEC 497 err |= __get_user(v_regs, &sc->v_regs); 498 err |= __get_user(tm_v_regs, &tm_sc->v_regs); 499 if (err) 500 return err; 501 if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128))) 502 return -EFAULT; 503 if (tm_v_regs && !access_ok(tm_v_regs, 34 * sizeof(vector128))) 504 return -EFAULT; 505 /* Copy 33 vec registers (vr0..31 and vscr) from the stack */ 506 if (v_regs != NULL && tm_v_regs != NULL && (msr & MSR_VEC) != 0) { 507 err |= __copy_from_user(&tsk->thread.ckvr_state, v_regs, 508 33 * sizeof(vector128)); 509 err |= __copy_from_user(&tsk->thread.vr_state, tm_v_regs, 510 33 * sizeof(vector128)); 511 current->thread.used_vr = true; 512 } 513 else if (tsk->thread.used_vr) { 514 memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128)); 515 memset(&tsk->thread.ckvr_state, 0, 33 * sizeof(vector128)); 516 } 517 /* Always get VRSAVE back */ 518 if (v_regs != NULL && tm_v_regs != NULL) { 519 err |= __get_user(tsk->thread.ckvrsave, 520 (u32 __user *)&v_regs[33]); 521 err |= __get_user(tsk->thread.vrsave, 522 (u32 __user *)&tm_v_regs[33]); 523 } 524 else { 525 tsk->thread.vrsave = 0; 526 tsk->thread.ckvrsave = 0; 527 } 528 if (cpu_has_feature(CPU_FTR_ALTIVEC)) 529 mtspr(SPRN_VRSAVE, tsk->thread.vrsave); 530 #endif /* CONFIG_ALTIVEC */ 531 /* restore floating point */ 532 err |= copy_fpr_from_user(tsk, &tm_sc->fp_regs); 533 err |= copy_ckfpr_from_user(tsk, &sc->fp_regs); 534 #ifdef CONFIG_VSX 535 /* 536 * Get additional VSX data. Update v_regs to point after the 537 * VMX data. Copy VSX low doubleword from userspace to local 538 * buffer for formatting, then into the taskstruct. 539 */ 540 if (v_regs && ((msr & MSR_VSX) != 0)) { 541 v_regs += ELF_NVRREG; 542 tm_v_regs += ELF_NVRREG; 543 err |= copy_vsx_from_user(tsk, tm_v_regs); 544 err |= copy_ckvsx_from_user(tsk, v_regs); 545 tsk->thread.used_vsr = true; 546 } else { 547 for (i = 0; i < 32 ; i++) { 548 tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0; 549 tsk->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET] = 0; 550 } 551 } 552 #endif 553 tm_enable(); 554 /* Make sure the transaction is marked as failed */ 555 tsk->thread.tm_texasr |= TEXASR_FS; 556 557 /* 558 * Disabling preemption, since it is unsafe to be preempted 559 * with MSR[TS] set without recheckpointing. 560 */ 561 preempt_disable(); 562 563 /* pull in MSR TS bits from user context */ 564 regs->msr |= msr & MSR_TS_MASK; 565 566 /* 567 * Ensure that TM is enabled in regs->msr before we leave the signal 568 * handler. It could be the case that (a) user disabled the TM bit 569 * through the manipulation of the MSR bits in uc_mcontext or (b) the 570 * TM bit was disabled because a sufficient number of context switches 571 * happened whilst in the signal handler and load_tm overflowed, 572 * disabling the TM bit. In either case we can end up with an illegal 573 * TM state leading to a TM Bad Thing when we return to userspace. 574 * 575 * CAUTION: 576 * After regs->MSR[TS] being updated, make sure that get_user(), 577 * put_user() or similar functions are *not* called. These 578 * functions can generate page faults which will cause the process 579 * to be de-scheduled with MSR[TS] set but without calling 580 * tm_recheckpoint(). This can cause a bug. 581 */ 582 regs->msr |= MSR_TM; 583 584 /* This loads the checkpointed FP/VEC state, if used */ 585 tm_recheckpoint(&tsk->thread); 586 587 msr_check_and_set(msr & (MSR_FP | MSR_VEC)); 588 if (msr & MSR_FP) { 589 load_fp_state(&tsk->thread.fp_state); 590 regs->msr |= (MSR_FP | tsk->thread.fpexc_mode); 591 } 592 if (msr & MSR_VEC) { 593 load_vr_state(&tsk->thread.vr_state); 594 regs->msr |= MSR_VEC; 595 } 596 597 preempt_enable(); 598 599 return err; 600 } 601 #endif 602 603 /* 604 * Setup the trampoline code on the stack 605 */ 606 static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp) 607 { 608 int i; 609 long err = 0; 610 611 /* addi r1, r1, __SIGNAL_FRAMESIZE # Pop the dummy stackframe */ 612 err |= __put_user(PPC_INST_ADDI | __PPC_RT(R1) | __PPC_RA(R1) | 613 (__SIGNAL_FRAMESIZE & 0xffff), &tramp[0]); 614 /* li r0, __NR_[rt_]sigreturn| */ 615 err |= __put_user(PPC_INST_ADDI | (syscall & 0xffff), &tramp[1]); 616 /* sc */ 617 err |= __put_user(PPC_INST_SC, &tramp[2]); 618 619 /* Minimal traceback info */ 620 for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++) 621 err |= __put_user(0, &tramp[i]); 622 623 if (!err) 624 flush_icache_range((unsigned long) &tramp[0], 625 (unsigned long) &tramp[TRAMP_SIZE]); 626 627 return err; 628 } 629 630 /* 631 * Userspace code may pass a ucontext which doesn't include VSX added 632 * at the end. We need to check for this case. 633 */ 634 #define UCONTEXTSIZEWITHOUTVSX \ 635 (sizeof(struct ucontext) - 32*sizeof(long)) 636 637 /* 638 * Handle {get,set,swap}_context operations 639 */ 640 SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx, 641 struct ucontext __user *, new_ctx, long, ctx_size) 642 { 643 unsigned char tmp; 644 sigset_t set; 645 unsigned long new_msr = 0; 646 int ctx_has_vsx_region = 0; 647 648 if (new_ctx && 649 get_user(new_msr, &new_ctx->uc_mcontext.gp_regs[PT_MSR])) 650 return -EFAULT; 651 /* 652 * Check that the context is not smaller than the original 653 * size (with VMX but without VSX) 654 */ 655 if (ctx_size < UCONTEXTSIZEWITHOUTVSX) 656 return -EINVAL; 657 /* 658 * If the new context state sets the MSR VSX bits but 659 * it doesn't provide VSX state. 660 */ 661 if ((ctx_size < sizeof(struct ucontext)) && 662 (new_msr & MSR_VSX)) 663 return -EINVAL; 664 /* Does the context have enough room to store VSX data? */ 665 if (ctx_size >= sizeof(struct ucontext)) 666 ctx_has_vsx_region = 1; 667 668 if (old_ctx != NULL) { 669 if (!access_ok(old_ctx, ctx_size) 670 || setup_sigcontext(&old_ctx->uc_mcontext, current, 0, NULL, 0, 671 ctx_has_vsx_region) 672 || __copy_to_user(&old_ctx->uc_sigmask, 673 ¤t->blocked, sizeof(sigset_t))) 674 return -EFAULT; 675 } 676 if (new_ctx == NULL) 677 return 0; 678 if (!access_ok(new_ctx, ctx_size) 679 || __get_user(tmp, (u8 __user *) new_ctx) 680 || __get_user(tmp, (u8 __user *) new_ctx + ctx_size - 1)) 681 return -EFAULT; 682 683 /* 684 * If we get a fault copying the context into the kernel's 685 * image of the user's registers, we can't just return -EFAULT 686 * because the user's registers will be corrupted. For instance 687 * the NIP value may have been updated but not some of the 688 * other registers. Given that we have done the access_ok 689 * and successfully read the first and last bytes of the region 690 * above, this should only happen in an out-of-memory situation 691 * or if another thread unmaps the region containing the context. 692 * We kill the task with a SIGSEGV in this situation. 693 */ 694 695 if (__copy_from_user(&set, &new_ctx->uc_sigmask, sizeof(set))) 696 do_exit(SIGSEGV); 697 set_current_blocked(&set); 698 if (restore_sigcontext(current, NULL, 0, &new_ctx->uc_mcontext)) 699 do_exit(SIGSEGV); 700 701 /* This returns like rt_sigreturn */ 702 set_thread_flag(TIF_RESTOREALL); 703 return 0; 704 } 705 706 707 /* 708 * Do a signal return; undo the signal stack. 709 */ 710 711 SYSCALL_DEFINE0(rt_sigreturn) 712 { 713 struct pt_regs *regs = current_pt_regs(); 714 struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1]; 715 sigset_t set; 716 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM 717 unsigned long msr; 718 #endif 719 720 /* Always make any pending restarted system calls return -EINTR */ 721 current->restart_block.fn = do_no_restart_syscall; 722 723 if (!access_ok(uc, sizeof(*uc))) 724 goto badframe; 725 726 if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set))) 727 goto badframe; 728 set_current_blocked(&set); 729 730 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM 731 /* 732 * If there is a transactional state then throw it away. 733 * The purpose of a sigreturn is to destroy all traces of the 734 * signal frame, this includes any transactional state created 735 * within in. We only check for suspended as we can never be 736 * active in the kernel, we are active, there is nothing better to 737 * do than go ahead and Bad Thing later. 738 * The cause is not important as there will never be a 739 * recheckpoint so it's not user visible. 740 */ 741 if (MSR_TM_SUSPENDED(mfmsr())) 742 tm_reclaim_current(0); 743 744 /* 745 * Disable MSR[TS] bit also, so, if there is an exception in the 746 * code below (as a page fault in copy_ckvsx_to_user()), it does 747 * not recheckpoint this task if there was a context switch inside 748 * the exception. 749 * 750 * A major page fault can indirectly call schedule(). A reschedule 751 * process in the middle of an exception can have a side effect 752 * (Changing the CPU MSR[TS] state), since schedule() is called 753 * with the CPU MSR[TS] disable and returns with MSR[TS]=Suspended 754 * (switch_to() calls tm_recheckpoint() for the 'new' process). In 755 * this case, the process continues to be the same in the CPU, but 756 * the CPU state just changed. 757 * 758 * This can cause a TM Bad Thing, since the MSR in the stack will 759 * have the MSR[TS]=0, and this is what will be used to RFID. 760 * 761 * Clearing MSR[TS] state here will avoid a recheckpoint if there 762 * is any process reschedule in kernel space. The MSR[TS] state 763 * does not need to be saved also, since it will be replaced with 764 * the MSR[TS] that came from user context later, at 765 * restore_tm_sigcontexts. 766 */ 767 regs->msr &= ~MSR_TS_MASK; 768 769 if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR])) 770 goto badframe; 771 if (MSR_TM_ACTIVE(msr)) { 772 /* We recheckpoint on return. */ 773 struct ucontext __user *uc_transact; 774 if (__get_user(uc_transact, &uc->uc_link)) 775 goto badframe; 776 if (restore_tm_sigcontexts(current, &uc->uc_mcontext, 777 &uc_transact->uc_mcontext)) 778 goto badframe; 779 } else 780 #endif 781 { 782 /* 783 * Fall through, for non-TM restore 784 * 785 * Unset MSR[TS] on the thread regs since MSR from user 786 * context does not have MSR active, and recheckpoint was 787 * not called since restore_tm_sigcontexts() was not called 788 * also. 789 * 790 * If not unsetting it, the code can RFID to userspace with 791 * MSR[TS] set, but without CPU in the proper state, 792 * causing a TM bad thing. 793 */ 794 current->thread.regs->msr &= ~MSR_TS_MASK; 795 if (restore_sigcontext(current, NULL, 1, &uc->uc_mcontext)) 796 goto badframe; 797 } 798 799 if (restore_altstack(&uc->uc_stack)) 800 goto badframe; 801 802 set_thread_flag(TIF_RESTOREALL); 803 return 0; 804 805 badframe: 806 if (show_unhandled_signals) 807 printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32, 808 current->comm, current->pid, "rt_sigreturn", 809 (long)uc, regs->nip, regs->link); 810 811 force_sig(SIGSEGV, current); 812 return 0; 813 } 814 815 int handle_rt_signal64(struct ksignal *ksig, sigset_t *set, 816 struct task_struct *tsk) 817 { 818 struct rt_sigframe __user *frame; 819 unsigned long newsp = 0; 820 long err = 0; 821 struct pt_regs *regs = tsk->thread.regs; 822 823 BUG_ON(tsk != current); 824 825 frame = get_sigframe(ksig, get_tm_stackpointer(tsk), sizeof(*frame), 0); 826 if (unlikely(frame == NULL)) 827 goto badframe; 828 829 err |= __put_user(&frame->info, &frame->pinfo); 830 err |= __put_user(&frame->uc, &frame->puc); 831 err |= copy_siginfo_to_user(&frame->info, &ksig->info); 832 if (err) 833 goto badframe; 834 835 /* Create the ucontext. */ 836 err |= __put_user(0, &frame->uc.uc_flags); 837 err |= __save_altstack(&frame->uc.uc_stack, regs->gpr[1]); 838 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM 839 if (MSR_TM_ACTIVE(regs->msr)) { 840 /* The ucontext_t passed to userland points to the second 841 * ucontext_t (for transactional state) with its uc_link ptr. 842 */ 843 err |= __put_user(&frame->uc_transact, &frame->uc.uc_link); 844 err |= setup_tm_sigcontexts(&frame->uc.uc_mcontext, 845 &frame->uc_transact.uc_mcontext, 846 tsk, ksig->sig, NULL, 847 (unsigned long)ksig->ka.sa.sa_handler); 848 } else 849 #endif 850 { 851 err |= __put_user(0, &frame->uc.uc_link); 852 err |= setup_sigcontext(&frame->uc.uc_mcontext, tsk, ksig->sig, 853 NULL, (unsigned long)ksig->ka.sa.sa_handler, 854 1); 855 } 856 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 857 if (err) 858 goto badframe; 859 860 /* Make sure signal handler doesn't get spurious FP exceptions */ 861 tsk->thread.fp_state.fpscr = 0; 862 863 /* Set up to return from userspace. */ 864 if (vdso64_rt_sigtramp && tsk->mm->context.vdso_base) { 865 regs->link = tsk->mm->context.vdso_base + vdso64_rt_sigtramp; 866 } else { 867 err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]); 868 if (err) 869 goto badframe; 870 regs->link = (unsigned long) &frame->tramp[0]; 871 } 872 873 /* Allocate a dummy caller frame for the signal handler. */ 874 newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE; 875 err |= put_user(regs->gpr[1], (unsigned long __user *)newsp); 876 877 /* Set up "regs" so we "return" to the signal handler. */ 878 if (is_elf2_task()) { 879 regs->nip = (unsigned long) ksig->ka.sa.sa_handler; 880 regs->gpr[12] = regs->nip; 881 } else { 882 /* Handler is *really* a pointer to the function descriptor for 883 * the signal routine. The first entry in the function 884 * descriptor is the entry address of signal and the second 885 * entry is the TOC value we need to use. 886 */ 887 func_descr_t __user *funct_desc_ptr = 888 (func_descr_t __user *) ksig->ka.sa.sa_handler; 889 890 err |= get_user(regs->nip, &funct_desc_ptr->entry); 891 err |= get_user(regs->gpr[2], &funct_desc_ptr->toc); 892 } 893 894 /* enter the signal handler in native-endian mode */ 895 regs->msr &= ~MSR_LE; 896 regs->msr |= (MSR_KERNEL & MSR_LE); 897 regs->gpr[1] = newsp; 898 regs->gpr[3] = ksig->sig; 899 regs->result = 0; 900 if (ksig->ka.sa.sa_flags & SA_SIGINFO) { 901 err |= get_user(regs->gpr[4], (unsigned long __user *)&frame->pinfo); 902 err |= get_user(regs->gpr[5], (unsigned long __user *)&frame->puc); 903 regs->gpr[6] = (unsigned long) frame; 904 } else { 905 regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext; 906 } 907 if (err) 908 goto badframe; 909 910 return 0; 911 912 badframe: 913 if (show_unhandled_signals) 914 printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32, 915 tsk->comm, tsk->pid, "setup_rt_frame", 916 (long)frame, regs->nip, regs->link); 917 918 return 1; 919 } 920