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 unsigned long msr) 197 { 198 /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the 199 * process never used altivec yet (MSR_VEC is zero in pt_regs of 200 * the context). This is very important because we must ensure we 201 * don't lose the VRSAVE content that may have been set prior to 202 * the process doing its first vector operation 203 * Userland shall check AT_HWCAP to know wether it can rely on the 204 * v_regs pointer or not. 205 */ 206 #ifdef CONFIG_ALTIVEC 207 elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc); 208 elf_vrreg_t __user *tm_v_regs = sigcontext_vmx_regs(tm_sc); 209 #endif 210 struct pt_regs *regs = tsk->thread.regs; 211 long err = 0; 212 213 BUG_ON(tsk != current); 214 215 BUG_ON(!MSR_TM_ACTIVE(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 #ifdef CONFIG_ALTIVEC 226 err |= __put_user(v_regs, &sc->v_regs); 227 err |= __put_user(tm_v_regs, &tm_sc->v_regs); 228 229 /* save altivec registers */ 230 if (tsk->thread.used_vr) { 231 /* Copy 33 vec registers (vr0..31 and vscr) to the stack */ 232 err |= __copy_to_user(v_regs, &tsk->thread.ckvr_state, 233 33 * sizeof(vector128)); 234 /* If VEC was enabled there are transactional VRs valid too, 235 * else they're a copy of the checkpointed VRs. 236 */ 237 if (msr & MSR_VEC) 238 err |= __copy_to_user(tm_v_regs, 239 &tsk->thread.vr_state, 240 33 * sizeof(vector128)); 241 else 242 err |= __copy_to_user(tm_v_regs, 243 &tsk->thread.ckvr_state, 244 33 * sizeof(vector128)); 245 246 /* set MSR_VEC in the MSR value in the frame to indicate 247 * that sc->v_reg contains valid data. 248 */ 249 msr |= MSR_VEC; 250 } 251 /* We always copy to/from vrsave, it's 0 if we don't have or don't 252 * use altivec. 253 */ 254 if (cpu_has_feature(CPU_FTR_ALTIVEC)) 255 tsk->thread.ckvrsave = mfspr(SPRN_VRSAVE); 256 err |= __put_user(tsk->thread.ckvrsave, (u32 __user *)&v_regs[33]); 257 if (msr & MSR_VEC) 258 err |= __put_user(tsk->thread.vrsave, 259 (u32 __user *)&tm_v_regs[33]); 260 else 261 err |= __put_user(tsk->thread.ckvrsave, 262 (u32 __user *)&tm_v_regs[33]); 263 264 #else /* CONFIG_ALTIVEC */ 265 err |= __put_user(0, &sc->v_regs); 266 err |= __put_user(0, &tm_sc->v_regs); 267 #endif /* CONFIG_ALTIVEC */ 268 269 /* copy fpr regs and fpscr */ 270 err |= copy_ckfpr_to_user(&sc->fp_regs, tsk); 271 if (msr & MSR_FP) 272 err |= copy_fpr_to_user(&tm_sc->fp_regs, tsk); 273 else 274 err |= copy_ckfpr_to_user(&tm_sc->fp_regs, tsk); 275 276 #ifdef CONFIG_VSX 277 /* 278 * Copy VSX low doubleword to local buffer for formatting, 279 * then out to userspace. Update v_regs to point after the 280 * VMX data. 281 */ 282 if (tsk->thread.used_vsr) { 283 v_regs += ELF_NVRREG; 284 tm_v_regs += ELF_NVRREG; 285 286 err |= copy_ckvsx_to_user(v_regs, tsk); 287 288 if (msr & MSR_VSX) 289 err |= copy_vsx_to_user(tm_v_regs, tsk); 290 else 291 err |= copy_ckvsx_to_user(tm_v_regs, tsk); 292 293 /* set MSR_VSX in the MSR value in the frame to 294 * indicate that sc->vs_reg) contains valid data. 295 */ 296 msr |= MSR_VSX; 297 } 298 #endif /* CONFIG_VSX */ 299 300 err |= __put_user(&sc->gp_regs, &sc->regs); 301 err |= __put_user(&tm_sc->gp_regs, &tm_sc->regs); 302 WARN_ON(!FULL_REGS(regs)); 303 err |= __copy_to_user(&tm_sc->gp_regs, regs, GP_REGS_SIZE); 304 err |= __copy_to_user(&sc->gp_regs, 305 &tsk->thread.ckpt_regs, GP_REGS_SIZE); 306 err |= __put_user(msr, &tm_sc->gp_regs[PT_MSR]); 307 err |= __put_user(msr, &sc->gp_regs[PT_MSR]); 308 err |= __put_user(signr, &sc->signal); 309 err |= __put_user(handler, &sc->handler); 310 if (set != NULL) 311 err |= __put_user(set->sig[0], &sc->oldmask); 312 313 return err; 314 } 315 #endif 316 317 /* 318 * Restore the sigcontext from the signal frame. 319 */ 320 321 static long restore_sigcontext(struct task_struct *tsk, sigset_t *set, int sig, 322 struct sigcontext __user *sc) 323 { 324 #ifdef CONFIG_ALTIVEC 325 elf_vrreg_t __user *v_regs; 326 #endif 327 unsigned long err = 0; 328 unsigned long save_r13 = 0; 329 unsigned long msr; 330 struct pt_regs *regs = tsk->thread.regs; 331 #ifdef CONFIG_VSX 332 int i; 333 #endif 334 335 BUG_ON(tsk != current); 336 337 /* If this is not a signal return, we preserve the TLS in r13 */ 338 if (!sig) 339 save_r13 = regs->gpr[13]; 340 341 /* copy the GPRs */ 342 err |= __copy_from_user(regs->gpr, sc->gp_regs, sizeof(regs->gpr)); 343 err |= __get_user(regs->nip, &sc->gp_regs[PT_NIP]); 344 /* get MSR separately, transfer the LE bit if doing signal return */ 345 err |= __get_user(msr, &sc->gp_regs[PT_MSR]); 346 if (sig) 347 regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE); 348 err |= __get_user(regs->orig_gpr3, &sc->gp_regs[PT_ORIG_R3]); 349 err |= __get_user(regs->ctr, &sc->gp_regs[PT_CTR]); 350 err |= __get_user(regs->link, &sc->gp_regs[PT_LNK]); 351 err |= __get_user(regs->xer, &sc->gp_regs[PT_XER]); 352 err |= __get_user(regs->ccr, &sc->gp_regs[PT_CCR]); 353 /* skip SOFTE */ 354 regs->trap = 0; 355 err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]); 356 err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]); 357 err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]); 358 359 if (!sig) 360 regs->gpr[13] = save_r13; 361 if (set != NULL) 362 err |= __get_user(set->sig[0], &sc->oldmask); 363 364 /* 365 * Force reload of FP/VEC. 366 * This has to be done before copying stuff into tsk->thread.fpr/vr 367 * for the reasons explained in the previous comment. 368 */ 369 regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX); 370 371 #ifdef CONFIG_ALTIVEC 372 err |= __get_user(v_regs, &sc->v_regs); 373 if (err) 374 return err; 375 if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128))) 376 return -EFAULT; 377 /* Copy 33 vec registers (vr0..31 and vscr) from the stack */ 378 if (v_regs != NULL && (msr & MSR_VEC) != 0) { 379 err |= __copy_from_user(&tsk->thread.vr_state, v_regs, 380 33 * sizeof(vector128)); 381 tsk->thread.used_vr = true; 382 } else if (tsk->thread.used_vr) { 383 memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128)); 384 } 385 /* Always get VRSAVE back */ 386 if (v_regs != NULL) 387 err |= __get_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33]); 388 else 389 tsk->thread.vrsave = 0; 390 if (cpu_has_feature(CPU_FTR_ALTIVEC)) 391 mtspr(SPRN_VRSAVE, tsk->thread.vrsave); 392 #endif /* CONFIG_ALTIVEC */ 393 /* restore floating point */ 394 err |= copy_fpr_from_user(tsk, &sc->fp_regs); 395 #ifdef CONFIG_VSX 396 /* 397 * Get additional VSX data. Update v_regs to point after the 398 * VMX data. Copy VSX low doubleword from userspace to local 399 * buffer for formatting, then into the taskstruct. 400 */ 401 v_regs += ELF_NVRREG; 402 if ((msr & MSR_VSX) != 0) { 403 err |= copy_vsx_from_user(tsk, v_regs); 404 tsk->thread.used_vsr = true; 405 } else { 406 for (i = 0; i < 32 ; i++) 407 tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0; 408 } 409 #endif 410 return err; 411 } 412 413 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM 414 /* 415 * Restore the two sigcontexts from the frame of a transactional processes. 416 */ 417 418 static long restore_tm_sigcontexts(struct task_struct *tsk, 419 struct sigcontext __user *sc, 420 struct sigcontext __user *tm_sc) 421 { 422 #ifdef CONFIG_ALTIVEC 423 elf_vrreg_t __user *v_regs, *tm_v_regs; 424 #endif 425 unsigned long err = 0; 426 unsigned long msr; 427 struct pt_regs *regs = tsk->thread.regs; 428 #ifdef CONFIG_VSX 429 int i; 430 #endif 431 432 BUG_ON(tsk != current); 433 434 if (tm_suspend_disabled) 435 return -EINVAL; 436 437 /* copy the GPRs */ 438 err |= __copy_from_user(regs->gpr, tm_sc->gp_regs, sizeof(regs->gpr)); 439 err |= __copy_from_user(&tsk->thread.ckpt_regs, sc->gp_regs, 440 sizeof(regs->gpr)); 441 442 /* 443 * TFHAR is restored from the checkpointed 'wound-back' ucontext's NIP. 444 * TEXASR was set by the signal delivery reclaim, as was TFIAR. 445 * Users doing anything abhorrent like thread-switching w/ signals for 446 * TM-Suspended code will have to back TEXASR/TFIAR up themselves. 447 * For the case of getting a signal and simply returning from it, 448 * we don't need to re-copy them here. 449 */ 450 err |= __get_user(regs->nip, &tm_sc->gp_regs[PT_NIP]); 451 err |= __get_user(tsk->thread.tm_tfhar, &sc->gp_regs[PT_NIP]); 452 453 /* get MSR separately, transfer the LE bit if doing signal return */ 454 err |= __get_user(msr, &sc->gp_regs[PT_MSR]); 455 /* Don't allow reserved mode. */ 456 if (MSR_TM_RESV(msr)) 457 return -EINVAL; 458 459 /* pull in MSR LE from user context */ 460 regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE); 461 462 /* The following non-GPR non-FPR non-VR state is also checkpointed: */ 463 err |= __get_user(regs->ctr, &tm_sc->gp_regs[PT_CTR]); 464 err |= __get_user(regs->link, &tm_sc->gp_regs[PT_LNK]); 465 err |= __get_user(regs->xer, &tm_sc->gp_regs[PT_XER]); 466 err |= __get_user(regs->ccr, &tm_sc->gp_regs[PT_CCR]); 467 err |= __get_user(tsk->thread.ckpt_regs.ctr, 468 &sc->gp_regs[PT_CTR]); 469 err |= __get_user(tsk->thread.ckpt_regs.link, 470 &sc->gp_regs[PT_LNK]); 471 err |= __get_user(tsk->thread.ckpt_regs.xer, 472 &sc->gp_regs[PT_XER]); 473 err |= __get_user(tsk->thread.ckpt_regs.ccr, 474 &sc->gp_regs[PT_CCR]); 475 476 /* Don't allow userspace to set the trap value */ 477 regs->trap = 0; 478 479 /* These regs are not checkpointed; they can go in 'regs'. */ 480 err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]); 481 err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]); 482 err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]); 483 484 /* 485 * Force reload of FP/VEC. 486 * This has to be done before copying stuff into tsk->thread.fpr/vr 487 * for the reasons explained in the previous comment. 488 */ 489 regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX); 490 491 #ifdef CONFIG_ALTIVEC 492 err |= __get_user(v_regs, &sc->v_regs); 493 err |= __get_user(tm_v_regs, &tm_sc->v_regs); 494 if (err) 495 return err; 496 if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128))) 497 return -EFAULT; 498 if (tm_v_regs && !access_ok(tm_v_regs, 34 * sizeof(vector128))) 499 return -EFAULT; 500 /* Copy 33 vec registers (vr0..31 and vscr) from the stack */ 501 if (v_regs != NULL && tm_v_regs != NULL && (msr & MSR_VEC) != 0) { 502 err |= __copy_from_user(&tsk->thread.ckvr_state, v_regs, 503 33 * sizeof(vector128)); 504 err |= __copy_from_user(&tsk->thread.vr_state, tm_v_regs, 505 33 * sizeof(vector128)); 506 current->thread.used_vr = true; 507 } 508 else if (tsk->thread.used_vr) { 509 memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128)); 510 memset(&tsk->thread.ckvr_state, 0, 33 * sizeof(vector128)); 511 } 512 /* Always get VRSAVE back */ 513 if (v_regs != NULL && tm_v_regs != NULL) { 514 err |= __get_user(tsk->thread.ckvrsave, 515 (u32 __user *)&v_regs[33]); 516 err |= __get_user(tsk->thread.vrsave, 517 (u32 __user *)&tm_v_regs[33]); 518 } 519 else { 520 tsk->thread.vrsave = 0; 521 tsk->thread.ckvrsave = 0; 522 } 523 if (cpu_has_feature(CPU_FTR_ALTIVEC)) 524 mtspr(SPRN_VRSAVE, tsk->thread.vrsave); 525 #endif /* CONFIG_ALTIVEC */ 526 /* restore floating point */ 527 err |= copy_fpr_from_user(tsk, &tm_sc->fp_regs); 528 err |= copy_ckfpr_from_user(tsk, &sc->fp_regs); 529 #ifdef CONFIG_VSX 530 /* 531 * Get additional VSX data. Update v_regs to point after the 532 * VMX data. Copy VSX low doubleword from userspace to local 533 * buffer for formatting, then into the taskstruct. 534 */ 535 if (v_regs && ((msr & MSR_VSX) != 0)) { 536 v_regs += ELF_NVRREG; 537 tm_v_regs += ELF_NVRREG; 538 err |= copy_vsx_from_user(tsk, tm_v_regs); 539 err |= copy_ckvsx_from_user(tsk, v_regs); 540 tsk->thread.used_vsr = true; 541 } else { 542 for (i = 0; i < 32 ; i++) { 543 tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0; 544 tsk->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET] = 0; 545 } 546 } 547 #endif 548 tm_enable(); 549 /* Make sure the transaction is marked as failed */ 550 tsk->thread.tm_texasr |= TEXASR_FS; 551 552 /* 553 * Disabling preemption, since it is unsafe to be preempted 554 * with MSR[TS] set without recheckpointing. 555 */ 556 preempt_disable(); 557 558 /* pull in MSR TS bits from user context */ 559 regs->msr |= msr & MSR_TS_MASK; 560 561 /* 562 * Ensure that TM is enabled in regs->msr before we leave the signal 563 * handler. It could be the case that (a) user disabled the TM bit 564 * through the manipulation of the MSR bits in uc_mcontext or (b) the 565 * TM bit was disabled because a sufficient number of context switches 566 * happened whilst in the signal handler and load_tm overflowed, 567 * disabling the TM bit. In either case we can end up with an illegal 568 * TM state leading to a TM Bad Thing when we return to userspace. 569 * 570 * CAUTION: 571 * After regs->MSR[TS] being updated, make sure that get_user(), 572 * put_user() or similar functions are *not* called. These 573 * functions can generate page faults which will cause the process 574 * to be de-scheduled with MSR[TS] set but without calling 575 * tm_recheckpoint(). This can cause a bug. 576 */ 577 regs->msr |= MSR_TM; 578 579 /* This loads the checkpointed FP/VEC state, if used */ 580 tm_recheckpoint(&tsk->thread); 581 582 msr_check_and_set(msr & (MSR_FP | MSR_VEC)); 583 if (msr & MSR_FP) { 584 load_fp_state(&tsk->thread.fp_state); 585 regs->msr |= (MSR_FP | tsk->thread.fpexc_mode); 586 } 587 if (msr & MSR_VEC) { 588 load_vr_state(&tsk->thread.vr_state); 589 regs->msr |= MSR_VEC; 590 } 591 592 preempt_enable(); 593 594 return err; 595 } 596 #endif 597 598 /* 599 * Setup the trampoline code on the stack 600 */ 601 static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp) 602 { 603 int i; 604 long err = 0; 605 606 /* addi r1, r1, __SIGNAL_FRAMESIZE # Pop the dummy stackframe */ 607 err |= __put_user(PPC_INST_ADDI | __PPC_RT(R1) | __PPC_RA(R1) | 608 (__SIGNAL_FRAMESIZE & 0xffff), &tramp[0]); 609 /* li r0, __NR_[rt_]sigreturn| */ 610 err |= __put_user(PPC_INST_ADDI | (syscall & 0xffff), &tramp[1]); 611 /* sc */ 612 err |= __put_user(PPC_INST_SC, &tramp[2]); 613 614 /* Minimal traceback info */ 615 for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++) 616 err |= __put_user(0, &tramp[i]); 617 618 if (!err) 619 flush_icache_range((unsigned long) &tramp[0], 620 (unsigned long) &tramp[TRAMP_SIZE]); 621 622 return err; 623 } 624 625 /* 626 * Userspace code may pass a ucontext which doesn't include VSX added 627 * at the end. We need to check for this case. 628 */ 629 #define UCONTEXTSIZEWITHOUTVSX \ 630 (sizeof(struct ucontext) - 32*sizeof(long)) 631 632 /* 633 * Handle {get,set,swap}_context operations 634 */ 635 SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx, 636 struct ucontext __user *, new_ctx, long, ctx_size) 637 { 638 unsigned char tmp; 639 sigset_t set; 640 unsigned long new_msr = 0; 641 int ctx_has_vsx_region = 0; 642 643 if (new_ctx && 644 get_user(new_msr, &new_ctx->uc_mcontext.gp_regs[PT_MSR])) 645 return -EFAULT; 646 /* 647 * Check that the context is not smaller than the original 648 * size (with VMX but without VSX) 649 */ 650 if (ctx_size < UCONTEXTSIZEWITHOUTVSX) 651 return -EINVAL; 652 /* 653 * If the new context state sets the MSR VSX bits but 654 * it doesn't provide VSX state. 655 */ 656 if ((ctx_size < sizeof(struct ucontext)) && 657 (new_msr & MSR_VSX)) 658 return -EINVAL; 659 /* Does the context have enough room to store VSX data? */ 660 if (ctx_size >= sizeof(struct ucontext)) 661 ctx_has_vsx_region = 1; 662 663 if (old_ctx != NULL) { 664 if (!access_ok(old_ctx, ctx_size) 665 || setup_sigcontext(&old_ctx->uc_mcontext, current, 0, NULL, 0, 666 ctx_has_vsx_region) 667 || __copy_to_user(&old_ctx->uc_sigmask, 668 ¤t->blocked, sizeof(sigset_t))) 669 return -EFAULT; 670 } 671 if (new_ctx == NULL) 672 return 0; 673 if (!access_ok(new_ctx, ctx_size) 674 || __get_user(tmp, (u8 __user *) new_ctx) 675 || __get_user(tmp, (u8 __user *) new_ctx + ctx_size - 1)) 676 return -EFAULT; 677 678 /* 679 * If we get a fault copying the context into the kernel's 680 * image of the user's registers, we can't just return -EFAULT 681 * because the user's registers will be corrupted. For instance 682 * the NIP value may have been updated but not some of the 683 * other registers. Given that we have done the access_ok 684 * and successfully read the first and last bytes of the region 685 * above, this should only happen in an out-of-memory situation 686 * or if another thread unmaps the region containing the context. 687 * We kill the task with a SIGSEGV in this situation. 688 */ 689 690 if (__copy_from_user(&set, &new_ctx->uc_sigmask, sizeof(set))) 691 do_exit(SIGSEGV); 692 set_current_blocked(&set); 693 if (restore_sigcontext(current, NULL, 0, &new_ctx->uc_mcontext)) 694 do_exit(SIGSEGV); 695 696 /* This returns like rt_sigreturn */ 697 set_thread_flag(TIF_RESTOREALL); 698 return 0; 699 } 700 701 702 /* 703 * Do a signal return; undo the signal stack. 704 */ 705 706 SYSCALL_DEFINE0(rt_sigreturn) 707 { 708 struct pt_regs *regs = current_pt_regs(); 709 struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1]; 710 sigset_t set; 711 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM 712 unsigned long msr; 713 #endif 714 715 /* Always make any pending restarted system calls return -EINTR */ 716 current->restart_block.fn = do_no_restart_syscall; 717 718 if (!access_ok(uc, sizeof(*uc))) 719 goto badframe; 720 721 if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set))) 722 goto badframe; 723 set_current_blocked(&set); 724 725 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM 726 /* 727 * If there is a transactional state then throw it away. 728 * The purpose of a sigreturn is to destroy all traces of the 729 * signal frame, this includes any transactional state created 730 * within in. We only check for suspended as we can never be 731 * active in the kernel, we are active, there is nothing better to 732 * do than go ahead and Bad Thing later. 733 * The cause is not important as there will never be a 734 * recheckpoint so it's not user visible. 735 */ 736 if (MSR_TM_SUSPENDED(mfmsr())) 737 tm_reclaim_current(0); 738 739 /* 740 * Disable MSR[TS] bit also, so, if there is an exception in the 741 * code below (as a page fault in copy_ckvsx_to_user()), it does 742 * not recheckpoint this task if there was a context switch inside 743 * the exception. 744 * 745 * A major page fault can indirectly call schedule(). A reschedule 746 * process in the middle of an exception can have a side effect 747 * (Changing the CPU MSR[TS] state), since schedule() is called 748 * with the CPU MSR[TS] disable and returns with MSR[TS]=Suspended 749 * (switch_to() calls tm_recheckpoint() for the 'new' process). In 750 * this case, the process continues to be the same in the CPU, but 751 * the CPU state just changed. 752 * 753 * This can cause a TM Bad Thing, since the MSR in the stack will 754 * have the MSR[TS]=0, and this is what will be used to RFID. 755 * 756 * Clearing MSR[TS] state here will avoid a recheckpoint if there 757 * is any process reschedule in kernel space. The MSR[TS] state 758 * does not need to be saved also, since it will be replaced with 759 * the MSR[TS] that came from user context later, at 760 * restore_tm_sigcontexts. 761 */ 762 regs->msr &= ~MSR_TS_MASK; 763 764 if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR])) 765 goto badframe; 766 if (MSR_TM_ACTIVE(msr)) { 767 /* We recheckpoint on return. */ 768 struct ucontext __user *uc_transact; 769 770 /* Trying to start TM on non TM system */ 771 if (!cpu_has_feature(CPU_FTR_TM)) 772 goto badframe; 773 774 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); 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 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM 823 /* Save the thread's msr before get_tm_stackpointer() changes it */ 824 unsigned long msr = regs->msr; 825 #endif 826 827 BUG_ON(tsk != current); 828 829 frame = get_sigframe(ksig, get_tm_stackpointer(tsk), sizeof(*frame), 0); 830 if (unlikely(frame == NULL)) 831 goto badframe; 832 833 err |= __put_user(&frame->info, &frame->pinfo); 834 err |= __put_user(&frame->uc, &frame->puc); 835 err |= copy_siginfo_to_user(&frame->info, &ksig->info); 836 if (err) 837 goto badframe; 838 839 /* Create the ucontext. */ 840 err |= __put_user(0, &frame->uc.uc_flags); 841 err |= __save_altstack(&frame->uc.uc_stack, regs->gpr[1]); 842 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM 843 if (MSR_TM_ACTIVE(msr)) { 844 /* The ucontext_t passed to userland points to the second 845 * ucontext_t (for transactional state) with its uc_link ptr. 846 */ 847 err |= __put_user(&frame->uc_transact, &frame->uc.uc_link); 848 err |= setup_tm_sigcontexts(&frame->uc.uc_mcontext, 849 &frame->uc_transact.uc_mcontext, 850 tsk, ksig->sig, NULL, 851 (unsigned long)ksig->ka.sa.sa_handler, 852 msr); 853 } else 854 #endif 855 { 856 err |= __put_user(0, &frame->uc.uc_link); 857 err |= setup_sigcontext(&frame->uc.uc_mcontext, tsk, ksig->sig, 858 NULL, (unsigned long)ksig->ka.sa.sa_handler, 859 1); 860 } 861 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 862 if (err) 863 goto badframe; 864 865 /* Make sure signal handler doesn't get spurious FP exceptions */ 866 tsk->thread.fp_state.fpscr = 0; 867 868 /* Set up to return from userspace. */ 869 if (vdso64_rt_sigtramp && tsk->mm->context.vdso_base) { 870 regs->link = tsk->mm->context.vdso_base + vdso64_rt_sigtramp; 871 } else { 872 err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]); 873 if (err) 874 goto badframe; 875 regs->link = (unsigned long) &frame->tramp[0]; 876 } 877 878 /* Allocate a dummy caller frame for the signal handler. */ 879 newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE; 880 err |= put_user(regs->gpr[1], (unsigned long __user *)newsp); 881 882 /* Set up "regs" so we "return" to the signal handler. */ 883 if (is_elf2_task()) { 884 regs->nip = (unsigned long) ksig->ka.sa.sa_handler; 885 regs->gpr[12] = regs->nip; 886 } else { 887 /* Handler is *really* a pointer to the function descriptor for 888 * the signal routine. The first entry in the function 889 * descriptor is the entry address of signal and the second 890 * entry is the TOC value we need to use. 891 */ 892 func_descr_t __user *funct_desc_ptr = 893 (func_descr_t __user *) ksig->ka.sa.sa_handler; 894 895 err |= get_user(regs->nip, &funct_desc_ptr->entry); 896 err |= get_user(regs->gpr[2], &funct_desc_ptr->toc); 897 } 898 899 /* enter the signal handler in native-endian mode */ 900 regs->msr &= ~MSR_LE; 901 regs->msr |= (MSR_KERNEL & MSR_LE); 902 regs->gpr[1] = newsp; 903 regs->gpr[3] = ksig->sig; 904 regs->result = 0; 905 if (ksig->ka.sa.sa_flags & SA_SIGINFO) { 906 err |= get_user(regs->gpr[4], (unsigned long __user *)&frame->pinfo); 907 err |= get_user(regs->gpr[5], (unsigned long __user *)&frame->puc); 908 regs->gpr[6] = (unsigned long) frame; 909 } else { 910 regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext; 911 } 912 if (err) 913 goto badframe; 914 915 return 0; 916 917 badframe: 918 if (show_unhandled_signals) 919 printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32, 920 tsk->comm, tsk->pid, "setup_rt_frame", 921 (long)frame, regs->nip, regs->link); 922 923 return 1; 924 } 925