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 #include <linux/pagemap.h> 25 26 #include <asm/sigcontext.h> 27 #include <asm/ucontext.h> 28 #include <linux/uaccess.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 4 44 #define TRAMP_SIZE 7 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 /* 70 * This computes a quad word aligned pointer inside the vmx_reserve array 71 * element. For historical reasons sigcontext might not be quad word aligned, 72 * but the location we write the VMX regs to must be. See the comment in 73 * sigcontext for more detail. 74 */ 75 #ifdef CONFIG_ALTIVEC 76 static elf_vrreg_t __user *sigcontext_vmx_regs(struct sigcontext __user *sc) 77 { 78 return (elf_vrreg_t __user *) (((unsigned long)sc->vmx_reserve + 15) & ~0xful); 79 } 80 #endif 81 82 static void prepare_setup_sigcontext(struct task_struct *tsk) 83 { 84 #ifdef CONFIG_ALTIVEC 85 /* save altivec registers */ 86 if (tsk->thread.used_vr) 87 flush_altivec_to_thread(tsk); 88 if (cpu_has_feature(CPU_FTR_ALTIVEC)) 89 tsk->thread.vrsave = mfspr(SPRN_VRSAVE); 90 #endif /* CONFIG_ALTIVEC */ 91 92 flush_fp_to_thread(tsk); 93 94 #ifdef CONFIG_VSX 95 if (tsk->thread.used_vsr) 96 flush_vsx_to_thread(tsk); 97 #endif /* CONFIG_VSX */ 98 } 99 100 /* 101 * Set up the sigcontext for the signal frame. 102 */ 103 104 #define unsafe_setup_sigcontext(sc, tsk, signr, set, handler, ctx_has_vsx_region, label)\ 105 do { \ 106 if (__unsafe_setup_sigcontext(sc, tsk, signr, set, handler, ctx_has_vsx_region))\ 107 goto label; \ 108 } while (0) 109 static long notrace __unsafe_setup_sigcontext(struct sigcontext __user *sc, 110 struct task_struct *tsk, int signr, sigset_t *set, 111 unsigned long handler, int ctx_has_vsx_region) 112 { 113 /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the 114 * process never used altivec yet (MSR_VEC is zero in pt_regs of 115 * the context). This is very important because we must ensure we 116 * don't lose the VRSAVE content that may have been set prior to 117 * the process doing its first vector operation 118 * Userland shall check AT_HWCAP to know whether it can rely on the 119 * v_regs pointer or not 120 */ 121 #ifdef CONFIG_ALTIVEC 122 elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc); 123 #endif 124 struct pt_regs *regs = tsk->thread.regs; 125 unsigned long msr = regs->msr; 126 /* Force usr to alway see softe as 1 (interrupts enabled) */ 127 unsigned long softe = 0x1; 128 129 BUG_ON(tsk != current); 130 131 #ifdef CONFIG_ALTIVEC 132 unsafe_put_user(v_regs, &sc->v_regs, efault_out); 133 134 /* save altivec registers */ 135 if (tsk->thread.used_vr) { 136 /* Copy 33 vec registers (vr0..31 and vscr) to the stack */ 137 unsafe_copy_to_user(v_regs, &tsk->thread.vr_state, 138 33 * sizeof(vector128), efault_out); 139 /* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg) 140 * contains valid data. 141 */ 142 msr |= MSR_VEC; 143 } 144 /* We always copy to/from vrsave, it's 0 if we don't have or don't 145 * use altivec. 146 */ 147 unsafe_put_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33], efault_out); 148 #else /* CONFIG_ALTIVEC */ 149 unsafe_put_user(0, &sc->v_regs, efault_out); 150 #endif /* CONFIG_ALTIVEC */ 151 /* copy fpr regs and fpscr */ 152 unsafe_copy_fpr_to_user(&sc->fp_regs, tsk, efault_out); 153 154 /* 155 * Clear the MSR VSX bit to indicate there is no valid state attached 156 * to this context, except in the specific case below where we set it. 157 */ 158 msr &= ~MSR_VSX; 159 #ifdef CONFIG_VSX 160 /* 161 * Copy VSX low doubleword to local buffer for formatting, 162 * then out to userspace. Update v_regs to point after the 163 * VMX data. 164 */ 165 if (tsk->thread.used_vsr && ctx_has_vsx_region) { 166 v_regs += ELF_NVRREG; 167 unsafe_copy_vsx_to_user(v_regs, tsk, efault_out); 168 /* set MSR_VSX in the MSR value in the frame to 169 * indicate that sc->vs_reg) contains valid data. 170 */ 171 msr |= MSR_VSX; 172 } 173 #endif /* CONFIG_VSX */ 174 unsafe_put_user(&sc->gp_regs, &sc->regs, efault_out); 175 unsafe_copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE, efault_out); 176 unsafe_put_user(msr, &sc->gp_regs[PT_MSR], efault_out); 177 unsafe_put_user(softe, &sc->gp_regs[PT_SOFTE], efault_out); 178 unsafe_put_user(signr, &sc->signal, efault_out); 179 unsafe_put_user(handler, &sc->handler, efault_out); 180 if (set != NULL) 181 unsafe_put_user(set->sig[0], &sc->oldmask, efault_out); 182 183 return 0; 184 185 efault_out: 186 return -EFAULT; 187 } 188 189 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM 190 /* 191 * As above, but Transactional Memory is in use, so deliver sigcontexts 192 * containing checkpointed and transactional register states. 193 * 194 * To do this, we treclaim (done before entering here) to gather both sets of 195 * registers and set up the 'normal' sigcontext registers with rolled-back 196 * register values such that a simple signal handler sees a correct 197 * checkpointed register state. If interested, a TM-aware sighandler can 198 * examine the transactional registers in the 2nd sigcontext to determine the 199 * real origin of the signal. 200 */ 201 static long setup_tm_sigcontexts(struct sigcontext __user *sc, 202 struct sigcontext __user *tm_sc, 203 struct task_struct *tsk, 204 int signr, sigset_t *set, unsigned long handler, 205 unsigned long msr) 206 { 207 /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the 208 * process never used altivec yet (MSR_VEC is zero in pt_regs of 209 * the context). This is very important because we must ensure we 210 * don't lose the VRSAVE content that may have been set prior to 211 * the process doing its first vector operation 212 * Userland shall check AT_HWCAP to know wether it can rely on the 213 * v_regs pointer or not. 214 */ 215 #ifdef CONFIG_ALTIVEC 216 elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc); 217 elf_vrreg_t __user *tm_v_regs = sigcontext_vmx_regs(tm_sc); 218 #endif 219 struct pt_regs *regs = tsk->thread.regs; 220 long err = 0; 221 222 BUG_ON(tsk != current); 223 224 BUG_ON(!MSR_TM_ACTIVE(msr)); 225 226 WARN_ON(tm_suspend_disabled); 227 228 /* Restore checkpointed FP, VEC, and VSX bits from ckpt_regs as 229 * it contains the correct FP, VEC, VSX state after we treclaimed 230 * the transaction and giveup_all() was called on reclaiming. 231 */ 232 msr |= tsk->thread.ckpt_regs.msr & (MSR_FP | MSR_VEC | MSR_VSX); 233 234 #ifdef CONFIG_ALTIVEC 235 err |= __put_user(v_regs, &sc->v_regs); 236 err |= __put_user(tm_v_regs, &tm_sc->v_regs); 237 238 /* save altivec registers */ 239 if (tsk->thread.used_vr) { 240 /* Copy 33 vec registers (vr0..31 and vscr) to the stack */ 241 err |= __copy_to_user(v_regs, &tsk->thread.ckvr_state, 242 33 * sizeof(vector128)); 243 /* If VEC was enabled there are transactional VRs valid too, 244 * else they're a copy of the checkpointed VRs. 245 */ 246 if (msr & MSR_VEC) 247 err |= __copy_to_user(tm_v_regs, 248 &tsk->thread.vr_state, 249 33 * sizeof(vector128)); 250 else 251 err |= __copy_to_user(tm_v_regs, 252 &tsk->thread.ckvr_state, 253 33 * sizeof(vector128)); 254 255 /* set MSR_VEC in the MSR value in the frame to indicate 256 * that sc->v_reg contains valid data. 257 */ 258 msr |= MSR_VEC; 259 } 260 /* We always copy to/from vrsave, it's 0 if we don't have or don't 261 * use altivec. 262 */ 263 if (cpu_has_feature(CPU_FTR_ALTIVEC)) 264 tsk->thread.ckvrsave = mfspr(SPRN_VRSAVE); 265 err |= __put_user(tsk->thread.ckvrsave, (u32 __user *)&v_regs[33]); 266 if (msr & MSR_VEC) 267 err |= __put_user(tsk->thread.vrsave, 268 (u32 __user *)&tm_v_regs[33]); 269 else 270 err |= __put_user(tsk->thread.ckvrsave, 271 (u32 __user *)&tm_v_regs[33]); 272 273 #else /* CONFIG_ALTIVEC */ 274 err |= __put_user(0, &sc->v_regs); 275 err |= __put_user(0, &tm_sc->v_regs); 276 #endif /* CONFIG_ALTIVEC */ 277 278 /* copy fpr regs and fpscr */ 279 err |= copy_ckfpr_to_user(&sc->fp_regs, tsk); 280 if (msr & MSR_FP) 281 err |= copy_fpr_to_user(&tm_sc->fp_regs, tsk); 282 else 283 err |= copy_ckfpr_to_user(&tm_sc->fp_regs, tsk); 284 285 #ifdef CONFIG_VSX 286 /* 287 * Copy VSX low doubleword to local buffer for formatting, 288 * then out to userspace. Update v_regs to point after the 289 * VMX data. 290 */ 291 if (tsk->thread.used_vsr) { 292 v_regs += ELF_NVRREG; 293 tm_v_regs += ELF_NVRREG; 294 295 err |= copy_ckvsx_to_user(v_regs, tsk); 296 297 if (msr & MSR_VSX) 298 err |= copy_vsx_to_user(tm_v_regs, tsk); 299 else 300 err |= copy_ckvsx_to_user(tm_v_regs, tsk); 301 302 /* set MSR_VSX in the MSR value in the frame to 303 * indicate that sc->vs_reg) contains valid data. 304 */ 305 msr |= MSR_VSX; 306 } 307 #endif /* CONFIG_VSX */ 308 309 err |= __put_user(&sc->gp_regs, &sc->regs); 310 err |= __put_user(&tm_sc->gp_regs, &tm_sc->regs); 311 err |= __copy_to_user(&tm_sc->gp_regs, regs, GP_REGS_SIZE); 312 err |= __copy_to_user(&sc->gp_regs, 313 &tsk->thread.ckpt_regs, GP_REGS_SIZE); 314 err |= __put_user(msr, &tm_sc->gp_regs[PT_MSR]); 315 err |= __put_user(msr, &sc->gp_regs[PT_MSR]); 316 err |= __put_user(signr, &sc->signal); 317 err |= __put_user(handler, &sc->handler); 318 if (set != NULL) 319 err |= __put_user(set->sig[0], &sc->oldmask); 320 321 return err; 322 } 323 #endif 324 325 /* 326 * Restore the sigcontext from the signal frame. 327 */ 328 #define unsafe_restore_sigcontext(tsk, set, sig, sc, label) do { \ 329 if (__unsafe_restore_sigcontext(tsk, set, sig, sc)) \ 330 goto label; \ 331 } while (0) 332 static long notrace __unsafe_restore_sigcontext(struct task_struct *tsk, sigset_t *set, 333 int sig, struct sigcontext __user *sc) 334 { 335 #ifdef CONFIG_ALTIVEC 336 elf_vrreg_t __user *v_regs; 337 #endif 338 unsigned long save_r13 = 0; 339 unsigned long msr; 340 struct pt_regs *regs = tsk->thread.regs; 341 #ifdef CONFIG_VSX 342 int i; 343 #endif 344 345 BUG_ON(tsk != current); 346 347 /* If this is not a signal return, we preserve the TLS in r13 */ 348 if (!sig) 349 save_r13 = regs->gpr[13]; 350 351 /* copy the GPRs */ 352 unsafe_copy_from_user(regs->gpr, sc->gp_regs, sizeof(regs->gpr), efault_out); 353 unsafe_get_user(regs->nip, &sc->gp_regs[PT_NIP], efault_out); 354 /* get MSR separately, transfer the LE bit if doing signal return */ 355 unsafe_get_user(msr, &sc->gp_regs[PT_MSR], efault_out); 356 if (sig) 357 regs_set_return_msr(regs, (regs->msr & ~MSR_LE) | (msr & MSR_LE)); 358 unsafe_get_user(regs->orig_gpr3, &sc->gp_regs[PT_ORIG_R3], efault_out); 359 unsafe_get_user(regs->ctr, &sc->gp_regs[PT_CTR], efault_out); 360 unsafe_get_user(regs->link, &sc->gp_regs[PT_LNK], efault_out); 361 unsafe_get_user(regs->xer, &sc->gp_regs[PT_XER], efault_out); 362 unsafe_get_user(regs->ccr, &sc->gp_regs[PT_CCR], efault_out); 363 /* Don't allow userspace to set SOFTE */ 364 set_trap_norestart(regs); 365 unsafe_get_user(regs->dar, &sc->gp_regs[PT_DAR], efault_out); 366 unsafe_get_user(regs->dsisr, &sc->gp_regs[PT_DSISR], efault_out); 367 unsafe_get_user(regs->result, &sc->gp_regs[PT_RESULT], efault_out); 368 369 if (!sig) 370 regs->gpr[13] = save_r13; 371 if (set != NULL) 372 unsafe_get_user(set->sig[0], &sc->oldmask, efault_out); 373 374 /* 375 * Force reload of FP/VEC. 376 * This has to be done before copying stuff into tsk->thread.fpr/vr 377 * for the reasons explained in the previous comment. 378 */ 379 regs_set_return_msr(regs, regs->msr & ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX)); 380 381 #ifdef CONFIG_ALTIVEC 382 unsafe_get_user(v_regs, &sc->v_regs, efault_out); 383 if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128))) 384 return -EFAULT; 385 /* Copy 33 vec registers (vr0..31 and vscr) from the stack */ 386 if (v_regs != NULL && (msr & MSR_VEC) != 0) { 387 unsafe_copy_from_user(&tsk->thread.vr_state, v_regs, 388 33 * sizeof(vector128), efault_out); 389 tsk->thread.used_vr = true; 390 } else if (tsk->thread.used_vr) { 391 memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128)); 392 } 393 /* Always get VRSAVE back */ 394 if (v_regs != NULL) 395 unsafe_get_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33], efault_out); 396 else 397 tsk->thread.vrsave = 0; 398 if (cpu_has_feature(CPU_FTR_ALTIVEC)) 399 mtspr(SPRN_VRSAVE, tsk->thread.vrsave); 400 #endif /* CONFIG_ALTIVEC */ 401 /* restore floating point */ 402 unsafe_copy_fpr_from_user(tsk, &sc->fp_regs, efault_out); 403 #ifdef CONFIG_VSX 404 /* 405 * Get additional VSX data. Update v_regs to point after the 406 * VMX data. Copy VSX low doubleword from userspace to local 407 * buffer for formatting, then into the taskstruct. 408 */ 409 v_regs += ELF_NVRREG; 410 if ((msr & MSR_VSX) != 0) { 411 unsafe_copy_vsx_from_user(tsk, v_regs, efault_out); 412 tsk->thread.used_vsr = true; 413 } else { 414 for (i = 0; i < 32 ; i++) 415 tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0; 416 } 417 #endif 418 return 0; 419 420 efault_out: 421 return -EFAULT; 422 } 423 424 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM 425 /* 426 * Restore the two sigcontexts from the frame of a transactional processes. 427 */ 428 429 static long restore_tm_sigcontexts(struct task_struct *tsk, 430 struct sigcontext __user *sc, 431 struct sigcontext __user *tm_sc) 432 { 433 #ifdef CONFIG_ALTIVEC 434 elf_vrreg_t __user *v_regs, *tm_v_regs; 435 #endif 436 unsigned long err = 0; 437 unsigned long msr; 438 struct pt_regs *regs = tsk->thread.regs; 439 #ifdef CONFIG_VSX 440 int i; 441 #endif 442 443 BUG_ON(tsk != current); 444 445 if (tm_suspend_disabled) 446 return -EINVAL; 447 448 /* copy the GPRs */ 449 err |= __copy_from_user(regs->gpr, tm_sc->gp_regs, sizeof(regs->gpr)); 450 err |= __copy_from_user(&tsk->thread.ckpt_regs, sc->gp_regs, 451 sizeof(regs->gpr)); 452 453 /* 454 * TFHAR is restored from the checkpointed 'wound-back' ucontext's NIP. 455 * TEXASR was set by the signal delivery reclaim, as was TFIAR. 456 * Users doing anything abhorrent like thread-switching w/ signals for 457 * TM-Suspended code will have to back TEXASR/TFIAR up themselves. 458 * For the case of getting a signal and simply returning from it, 459 * we don't need to re-copy them here. 460 */ 461 err |= __get_user(regs->nip, &tm_sc->gp_regs[PT_NIP]); 462 err |= __get_user(tsk->thread.tm_tfhar, &sc->gp_regs[PT_NIP]); 463 464 /* get MSR separately, transfer the LE bit if doing signal return */ 465 err |= __get_user(msr, &sc->gp_regs[PT_MSR]); 466 /* Don't allow reserved mode. */ 467 if (MSR_TM_RESV(msr)) 468 return -EINVAL; 469 470 /* pull in MSR LE from user context */ 471 regs_set_return_msr(regs, (regs->msr & ~MSR_LE) | (msr & MSR_LE)); 472 473 /* The following non-GPR non-FPR non-VR state is also checkpointed: */ 474 err |= __get_user(regs->ctr, &tm_sc->gp_regs[PT_CTR]); 475 err |= __get_user(regs->link, &tm_sc->gp_regs[PT_LNK]); 476 err |= __get_user(regs->xer, &tm_sc->gp_regs[PT_XER]); 477 err |= __get_user(regs->ccr, &tm_sc->gp_regs[PT_CCR]); 478 err |= __get_user(tsk->thread.ckpt_regs.ctr, 479 &sc->gp_regs[PT_CTR]); 480 err |= __get_user(tsk->thread.ckpt_regs.link, 481 &sc->gp_regs[PT_LNK]); 482 err |= __get_user(tsk->thread.ckpt_regs.xer, 483 &sc->gp_regs[PT_XER]); 484 err |= __get_user(tsk->thread.ckpt_regs.ccr, 485 &sc->gp_regs[PT_CCR]); 486 /* Don't allow userspace to set SOFTE */ 487 set_trap_norestart(regs); 488 /* These regs are not checkpointed; they can go in 'regs'. */ 489 err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]); 490 err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]); 491 err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]); 492 493 /* 494 * Force reload of FP/VEC. 495 * This has to be done before copying stuff into tsk->thread.fpr/vr 496 * for the reasons explained in the previous comment. 497 */ 498 regs_set_return_msr(regs, regs->msr & ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX)); 499 500 #ifdef CONFIG_ALTIVEC 501 err |= __get_user(v_regs, &sc->v_regs); 502 err |= __get_user(tm_v_regs, &tm_sc->v_regs); 503 if (err) 504 return err; 505 if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128))) 506 return -EFAULT; 507 if (tm_v_regs && !access_ok(tm_v_regs, 34 * sizeof(vector128))) 508 return -EFAULT; 509 /* Copy 33 vec registers (vr0..31 and vscr) from the stack */ 510 if (v_regs != NULL && tm_v_regs != NULL && (msr & MSR_VEC) != 0) { 511 err |= __copy_from_user(&tsk->thread.ckvr_state, v_regs, 512 33 * sizeof(vector128)); 513 err |= __copy_from_user(&tsk->thread.vr_state, tm_v_regs, 514 33 * sizeof(vector128)); 515 current->thread.used_vr = true; 516 } 517 else if (tsk->thread.used_vr) { 518 memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128)); 519 memset(&tsk->thread.ckvr_state, 0, 33 * sizeof(vector128)); 520 } 521 /* Always get VRSAVE back */ 522 if (v_regs != NULL && tm_v_regs != NULL) { 523 err |= __get_user(tsk->thread.ckvrsave, 524 (u32 __user *)&v_regs[33]); 525 err |= __get_user(tsk->thread.vrsave, 526 (u32 __user *)&tm_v_regs[33]); 527 } 528 else { 529 tsk->thread.vrsave = 0; 530 tsk->thread.ckvrsave = 0; 531 } 532 if (cpu_has_feature(CPU_FTR_ALTIVEC)) 533 mtspr(SPRN_VRSAVE, tsk->thread.vrsave); 534 #endif /* CONFIG_ALTIVEC */ 535 /* restore floating point */ 536 err |= copy_fpr_from_user(tsk, &tm_sc->fp_regs); 537 err |= copy_ckfpr_from_user(tsk, &sc->fp_regs); 538 #ifdef CONFIG_VSX 539 /* 540 * Get additional VSX data. Update v_regs to point after the 541 * VMX data. Copy VSX low doubleword from userspace to local 542 * buffer for formatting, then into the taskstruct. 543 */ 544 if (v_regs && ((msr & MSR_VSX) != 0)) { 545 v_regs += ELF_NVRREG; 546 tm_v_regs += ELF_NVRREG; 547 err |= copy_vsx_from_user(tsk, tm_v_regs); 548 err |= copy_ckvsx_from_user(tsk, v_regs); 549 tsk->thread.used_vsr = true; 550 } else { 551 for (i = 0; i < 32 ; i++) { 552 tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0; 553 tsk->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET] = 0; 554 } 555 } 556 #endif 557 tm_enable(); 558 /* Make sure the transaction is marked as failed */ 559 tsk->thread.tm_texasr |= TEXASR_FS; 560 561 /* 562 * Disabling preemption, since it is unsafe to be preempted 563 * with MSR[TS] set without recheckpointing. 564 */ 565 preempt_disable(); 566 567 /* pull in MSR TS bits from user context */ 568 regs_set_return_msr(regs, regs->msr | (msr & MSR_TS_MASK)); 569 570 /* 571 * Ensure that TM is enabled in regs->msr before we leave the signal 572 * handler. It could be the case that (a) user disabled the TM bit 573 * through the manipulation of the MSR bits in uc_mcontext or (b) the 574 * TM bit was disabled because a sufficient number of context switches 575 * happened whilst in the signal handler and load_tm overflowed, 576 * disabling the TM bit. In either case we can end up with an illegal 577 * TM state leading to a TM Bad Thing when we return to userspace. 578 * 579 * CAUTION: 580 * After regs->MSR[TS] being updated, make sure that get_user(), 581 * put_user() or similar functions are *not* called. These 582 * functions can generate page faults which will cause the process 583 * to be de-scheduled with MSR[TS] set but without calling 584 * tm_recheckpoint(). This can cause a bug. 585 */ 586 regs_set_return_msr(regs, regs->msr | MSR_TM); 587 588 /* This loads the checkpointed FP/VEC state, if used */ 589 tm_recheckpoint(&tsk->thread); 590 591 msr_check_and_set(msr & (MSR_FP | MSR_VEC)); 592 if (msr & MSR_FP) { 593 load_fp_state(&tsk->thread.fp_state); 594 regs_set_return_msr(regs, regs->msr | (MSR_FP | tsk->thread.fpexc_mode)); 595 } 596 if (msr & MSR_VEC) { 597 load_vr_state(&tsk->thread.vr_state); 598 regs_set_return_msr(regs, regs->msr | MSR_VEC); 599 } 600 601 preempt_enable(); 602 603 return err; 604 } 605 #else /* !CONFIG_PPC_TRANSACTIONAL_MEM */ 606 static long restore_tm_sigcontexts(struct task_struct *tsk, struct sigcontext __user *sc, 607 struct sigcontext __user *tm_sc) 608 { 609 return -EINVAL; 610 } 611 #endif 612 613 /* 614 * Setup the trampoline code on the stack 615 */ 616 static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp) 617 { 618 int i; 619 long err = 0; 620 621 /* Call the handler and pop the dummy stackframe*/ 622 err |= __put_user(PPC_RAW_BCTRL(), &tramp[0]); 623 err |= __put_user(PPC_RAW_ADDI(_R1, _R1, __SIGNAL_FRAMESIZE), &tramp[1]); 624 625 err |= __put_user(PPC_RAW_LI(_R0, syscall), &tramp[2]); 626 err |= __put_user(PPC_RAW_SC(), &tramp[3]); 627 628 /* Minimal traceback info */ 629 for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++) 630 err |= __put_user(0, &tramp[i]); 631 632 if (!err) 633 flush_icache_range((unsigned long) &tramp[0], 634 (unsigned long) &tramp[TRAMP_SIZE]); 635 636 return err; 637 } 638 639 /* 640 * Userspace code may pass a ucontext which doesn't include VSX added 641 * at the end. We need to check for this case. 642 */ 643 #define UCONTEXTSIZEWITHOUTVSX \ 644 (sizeof(struct ucontext) - 32*sizeof(long)) 645 646 /* 647 * Handle {get,set,swap}_context operations 648 */ 649 SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx, 650 struct ucontext __user *, new_ctx, long, ctx_size) 651 { 652 sigset_t set; 653 unsigned long new_msr = 0; 654 int ctx_has_vsx_region = 0; 655 656 if (new_ctx && 657 get_user(new_msr, &new_ctx->uc_mcontext.gp_regs[PT_MSR])) 658 return -EFAULT; 659 /* 660 * Check that the context is not smaller than the original 661 * size (with VMX but without VSX) 662 */ 663 if (ctx_size < UCONTEXTSIZEWITHOUTVSX) 664 return -EINVAL; 665 /* 666 * If the new context state sets the MSR VSX bits but 667 * it doesn't provide VSX state. 668 */ 669 if ((ctx_size < sizeof(struct ucontext)) && 670 (new_msr & MSR_VSX)) 671 return -EINVAL; 672 /* Does the context have enough room to store VSX data? */ 673 if (ctx_size >= sizeof(struct ucontext)) 674 ctx_has_vsx_region = 1; 675 676 if (old_ctx != NULL) { 677 prepare_setup_sigcontext(current); 678 if (!user_write_access_begin(old_ctx, ctx_size)) 679 return -EFAULT; 680 681 unsafe_setup_sigcontext(&old_ctx->uc_mcontext, current, 0, NULL, 682 0, ctx_has_vsx_region, efault_out); 683 unsafe_copy_to_user(&old_ctx->uc_sigmask, ¤t->blocked, 684 sizeof(sigset_t), efault_out); 685 686 user_write_access_end(); 687 } 688 if (new_ctx == NULL) 689 return 0; 690 if (!access_ok(new_ctx, ctx_size) || 691 fault_in_pages_readable((u8 __user *)new_ctx, ctx_size)) 692 return -EFAULT; 693 694 /* 695 * If we get a fault copying the context into the kernel's 696 * image of the user's registers, we can't just return -EFAULT 697 * because the user's registers will be corrupted. For instance 698 * the NIP value may have been updated but not some of the 699 * other registers. Given that we have done the access_ok 700 * and successfully read the first and last bytes of the region 701 * above, this should only happen in an out-of-memory situation 702 * or if another thread unmaps the region containing the context. 703 * We kill the task with a SIGSEGV in this situation. 704 */ 705 706 if (__get_user_sigset(&set, &new_ctx->uc_sigmask)) 707 do_exit(SIGSEGV); 708 set_current_blocked(&set); 709 710 if (!user_read_access_begin(new_ctx, ctx_size)) 711 return -EFAULT; 712 if (__unsafe_restore_sigcontext(current, NULL, 0, &new_ctx->uc_mcontext)) { 713 user_read_access_end(); 714 do_exit(SIGSEGV); 715 } 716 user_read_access_end(); 717 718 /* This returns like rt_sigreturn */ 719 set_thread_flag(TIF_RESTOREALL); 720 721 return 0; 722 723 efault_out: 724 user_write_access_end(); 725 return -EFAULT; 726 } 727 728 729 /* 730 * Do a signal return; undo the signal stack. 731 */ 732 733 SYSCALL_DEFINE0(rt_sigreturn) 734 { 735 struct pt_regs *regs = current_pt_regs(); 736 struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1]; 737 sigset_t set; 738 unsigned long msr; 739 740 /* Always make any pending restarted system calls return -EINTR */ 741 current->restart_block.fn = do_no_restart_syscall; 742 743 if (!access_ok(uc, sizeof(*uc))) 744 goto badframe; 745 746 if (__get_user_sigset(&set, &uc->uc_sigmask)) 747 goto badframe; 748 set_current_blocked(&set); 749 750 if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM)) { 751 /* 752 * If there is a transactional state then throw it away. 753 * The purpose of a sigreturn is to destroy all traces of the 754 * signal frame, this includes any transactional state created 755 * within in. We only check for suspended as we can never be 756 * active in the kernel, we are active, there is nothing better to 757 * do than go ahead and Bad Thing later. 758 * The cause is not important as there will never be a 759 * recheckpoint so it's not user visible. 760 */ 761 if (MSR_TM_SUSPENDED(mfmsr())) 762 tm_reclaim_current(0); 763 764 /* 765 * Disable MSR[TS] bit also, so, if there is an exception in the 766 * code below (as a page fault in copy_ckvsx_to_user()), it does 767 * not recheckpoint this task if there was a context switch inside 768 * the exception. 769 * 770 * A major page fault can indirectly call schedule(). A reschedule 771 * process in the middle of an exception can have a side effect 772 * (Changing the CPU MSR[TS] state), since schedule() is called 773 * with the CPU MSR[TS] disable and returns with MSR[TS]=Suspended 774 * (switch_to() calls tm_recheckpoint() for the 'new' process). In 775 * this case, the process continues to be the same in the CPU, but 776 * the CPU state just changed. 777 * 778 * This can cause a TM Bad Thing, since the MSR in the stack will 779 * have the MSR[TS]=0, and this is what will be used to RFID. 780 * 781 * Clearing MSR[TS] state here will avoid a recheckpoint if there 782 * is any process reschedule in kernel space. The MSR[TS] state 783 * does not need to be saved also, since it will be replaced with 784 * the MSR[TS] that came from user context later, at 785 * restore_tm_sigcontexts. 786 */ 787 regs_set_return_msr(regs, regs->msr & ~MSR_TS_MASK); 788 789 if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR])) 790 goto badframe; 791 } 792 793 if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM) && MSR_TM_ACTIVE(msr)) { 794 /* We recheckpoint on return. */ 795 struct ucontext __user *uc_transact; 796 797 /* Trying to start TM on non TM system */ 798 if (!cpu_has_feature(CPU_FTR_TM)) 799 goto badframe; 800 801 if (__get_user(uc_transact, &uc->uc_link)) 802 goto badframe; 803 if (restore_tm_sigcontexts(current, &uc->uc_mcontext, 804 &uc_transact->uc_mcontext)) 805 goto badframe; 806 } else { 807 /* 808 * Fall through, for non-TM restore 809 * 810 * Unset MSR[TS] on the thread regs since MSR from user 811 * context does not have MSR active, and recheckpoint was 812 * not called since restore_tm_sigcontexts() was not called 813 * also. 814 * 815 * If not unsetting it, the code can RFID to userspace with 816 * MSR[TS] set, but without CPU in the proper state, 817 * causing a TM bad thing. 818 */ 819 regs_set_return_msr(current->thread.regs, 820 current->thread.regs->msr & ~MSR_TS_MASK); 821 if (!user_read_access_begin(&uc->uc_mcontext, sizeof(uc->uc_mcontext))) 822 goto badframe; 823 824 unsafe_restore_sigcontext(current, NULL, 1, &uc->uc_mcontext, 825 badframe_block); 826 827 user_read_access_end(); 828 } 829 830 if (restore_altstack(&uc->uc_stack)) 831 goto badframe; 832 833 set_thread_flag(TIF_RESTOREALL); 834 835 return 0; 836 837 badframe_block: 838 user_read_access_end(); 839 badframe: 840 signal_fault(current, regs, "rt_sigreturn", uc); 841 842 force_sig(SIGSEGV); 843 return 0; 844 } 845 846 int handle_rt_signal64(struct ksignal *ksig, sigset_t *set, 847 struct task_struct *tsk) 848 { 849 struct rt_sigframe __user *frame; 850 unsigned long newsp = 0; 851 long err = 0; 852 struct pt_regs *regs = tsk->thread.regs; 853 /* Save the thread's msr before get_tm_stackpointer() changes it */ 854 unsigned long msr = regs->msr; 855 856 frame = get_sigframe(ksig, tsk, sizeof(*frame), 0); 857 858 /* 859 * This only applies when calling unsafe_setup_sigcontext() and must be 860 * called before opening the uaccess window. 861 */ 862 if (!MSR_TM_ACTIVE(msr)) 863 prepare_setup_sigcontext(tsk); 864 865 if (!user_write_access_begin(frame, sizeof(*frame))) 866 goto badframe; 867 868 unsafe_put_user(&frame->info, &frame->pinfo, badframe_block); 869 unsafe_put_user(&frame->uc, &frame->puc, badframe_block); 870 871 /* Create the ucontext. */ 872 unsafe_put_user(0, &frame->uc.uc_flags, badframe_block); 873 unsafe_save_altstack(&frame->uc.uc_stack, regs->gpr[1], badframe_block); 874 875 if (MSR_TM_ACTIVE(msr)) { 876 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM 877 /* The ucontext_t passed to userland points to the second 878 * ucontext_t (for transactional state) with its uc_link ptr. 879 */ 880 unsafe_put_user(&frame->uc_transact, &frame->uc.uc_link, badframe_block); 881 882 user_write_access_end(); 883 884 err |= setup_tm_sigcontexts(&frame->uc.uc_mcontext, 885 &frame->uc_transact.uc_mcontext, 886 tsk, ksig->sig, NULL, 887 (unsigned long)ksig->ka.sa.sa_handler, 888 msr); 889 890 if (!user_write_access_begin(&frame->uc.uc_sigmask, 891 sizeof(frame->uc.uc_sigmask))) 892 goto badframe; 893 894 #endif 895 } else { 896 unsafe_put_user(0, &frame->uc.uc_link, badframe_block); 897 unsafe_setup_sigcontext(&frame->uc.uc_mcontext, tsk, ksig->sig, 898 NULL, (unsigned long)ksig->ka.sa.sa_handler, 899 1, badframe_block); 900 } 901 902 unsafe_copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set), badframe_block); 903 user_write_access_end(); 904 905 /* Save the siginfo outside of the unsafe block. */ 906 if (copy_siginfo_to_user(&frame->info, &ksig->info)) 907 goto badframe; 908 909 /* Make sure signal handler doesn't get spurious FP exceptions */ 910 tsk->thread.fp_state.fpscr = 0; 911 912 /* Set up to return from userspace. */ 913 if (tsk->mm->context.vdso) { 914 regs_set_return_ip(regs, VDSO64_SYMBOL(tsk->mm->context.vdso, sigtramp_rt64)); 915 } else { 916 err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]); 917 if (err) 918 goto badframe; 919 regs_set_return_ip(regs, (unsigned long) &frame->tramp[0]); 920 } 921 922 /* Allocate a dummy caller frame for the signal handler. */ 923 newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE; 924 err |= put_user(regs->gpr[1], (unsigned long __user *)newsp); 925 926 /* Set up "regs" so we "return" to the signal handler. */ 927 if (is_elf2_task()) { 928 regs->ctr = (unsigned long) ksig->ka.sa.sa_handler; 929 regs->gpr[12] = regs->ctr; 930 } else { 931 /* Handler is *really* a pointer to the function descriptor for 932 * the signal routine. The first entry in the function 933 * descriptor is the entry address of signal and the second 934 * entry is the TOC value we need to use. 935 */ 936 func_descr_t __user *funct_desc_ptr = 937 (func_descr_t __user *) ksig->ka.sa.sa_handler; 938 939 err |= get_user(regs->ctr, &funct_desc_ptr->entry); 940 err |= get_user(regs->gpr[2], &funct_desc_ptr->toc); 941 } 942 943 /* enter the signal handler in native-endian mode */ 944 regs_set_return_msr(regs, (regs->msr & ~MSR_LE) | (MSR_KERNEL & MSR_LE)); 945 regs->gpr[1] = newsp; 946 regs->gpr[3] = ksig->sig; 947 regs->result = 0; 948 if (ksig->ka.sa.sa_flags & SA_SIGINFO) { 949 regs->gpr[4] = (unsigned long)&frame->info; 950 regs->gpr[5] = (unsigned long)&frame->uc; 951 regs->gpr[6] = (unsigned long) frame; 952 } else { 953 regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext; 954 } 955 if (err) 956 goto badframe; 957 958 return 0; 959 960 badframe_block: 961 user_write_access_end(); 962 badframe: 963 signal_fault(current, regs, "handle_rt_signal64", frame); 964 965 return 1; 966 } 967