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 WARN_ON(!FULL_REGS(regs)); 176 unsafe_copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE, efault_out); 177 unsafe_put_user(msr, &sc->gp_regs[PT_MSR], efault_out); 178 unsafe_put_user(softe, &sc->gp_regs[PT_SOFTE], efault_out); 179 unsafe_put_user(signr, &sc->signal, efault_out); 180 unsafe_put_user(handler, &sc->handler, efault_out); 181 if (set != NULL) 182 unsafe_put_user(set->sig[0], &sc->oldmask, efault_out); 183 184 return 0; 185 186 efault_out: 187 return -EFAULT; 188 } 189 190 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM 191 /* 192 * As above, but Transactional Memory is in use, so deliver sigcontexts 193 * containing checkpointed and transactional register states. 194 * 195 * To do this, we treclaim (done before entering here) to gather both sets of 196 * registers and set up the 'normal' sigcontext registers with rolled-back 197 * register values such that a simple signal handler sees a correct 198 * checkpointed register state. If interested, a TM-aware sighandler can 199 * examine the transactional registers in the 2nd sigcontext to determine the 200 * real origin of the signal. 201 */ 202 static long setup_tm_sigcontexts(struct sigcontext __user *sc, 203 struct sigcontext __user *tm_sc, 204 struct task_struct *tsk, 205 int signr, sigset_t *set, unsigned long handler, 206 unsigned long msr) 207 { 208 /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the 209 * process never used altivec yet (MSR_VEC is zero in pt_regs of 210 * the context). This is very important because we must ensure we 211 * don't lose the VRSAVE content that may have been set prior to 212 * the process doing its first vector operation 213 * Userland shall check AT_HWCAP to know wether it can rely on the 214 * v_regs pointer or not. 215 */ 216 #ifdef CONFIG_ALTIVEC 217 elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc); 218 elf_vrreg_t __user *tm_v_regs = sigcontext_vmx_regs(tm_sc); 219 #endif 220 struct pt_regs *regs = tsk->thread.regs; 221 long err = 0; 222 223 BUG_ON(tsk != current); 224 225 BUG_ON(!MSR_TM_ACTIVE(msr)); 226 227 WARN_ON(tm_suspend_disabled); 228 229 /* Restore checkpointed FP, VEC, and VSX bits from ckpt_regs as 230 * it contains the correct FP, VEC, VSX state after we treclaimed 231 * the transaction and giveup_all() was called on reclaiming. 232 */ 233 msr |= tsk->thread.ckpt_regs.msr & (MSR_FP | MSR_VEC | MSR_VSX); 234 235 #ifdef CONFIG_ALTIVEC 236 err |= __put_user(v_regs, &sc->v_regs); 237 err |= __put_user(tm_v_regs, &tm_sc->v_regs); 238 239 /* save altivec registers */ 240 if (tsk->thread.used_vr) { 241 /* Copy 33 vec registers (vr0..31 and vscr) to the stack */ 242 err |= __copy_to_user(v_regs, &tsk->thread.ckvr_state, 243 33 * sizeof(vector128)); 244 /* If VEC was enabled there are transactional VRs valid too, 245 * else they're a copy of the checkpointed VRs. 246 */ 247 if (msr & MSR_VEC) 248 err |= __copy_to_user(tm_v_regs, 249 &tsk->thread.vr_state, 250 33 * sizeof(vector128)); 251 else 252 err |= __copy_to_user(tm_v_regs, 253 &tsk->thread.ckvr_state, 254 33 * sizeof(vector128)); 255 256 /* set MSR_VEC in the MSR value in the frame to indicate 257 * that sc->v_reg contains valid data. 258 */ 259 msr |= MSR_VEC; 260 } 261 /* We always copy to/from vrsave, it's 0 if we don't have or don't 262 * use altivec. 263 */ 264 if (cpu_has_feature(CPU_FTR_ALTIVEC)) 265 tsk->thread.ckvrsave = mfspr(SPRN_VRSAVE); 266 err |= __put_user(tsk->thread.ckvrsave, (u32 __user *)&v_regs[33]); 267 if (msr & MSR_VEC) 268 err |= __put_user(tsk->thread.vrsave, 269 (u32 __user *)&tm_v_regs[33]); 270 else 271 err |= __put_user(tsk->thread.ckvrsave, 272 (u32 __user *)&tm_v_regs[33]); 273 274 #else /* CONFIG_ALTIVEC */ 275 err |= __put_user(0, &sc->v_regs); 276 err |= __put_user(0, &tm_sc->v_regs); 277 #endif /* CONFIG_ALTIVEC */ 278 279 /* copy fpr regs and fpscr */ 280 err |= copy_ckfpr_to_user(&sc->fp_regs, tsk); 281 if (msr & MSR_FP) 282 err |= copy_fpr_to_user(&tm_sc->fp_regs, tsk); 283 else 284 err |= copy_ckfpr_to_user(&tm_sc->fp_regs, tsk); 285 286 #ifdef CONFIG_VSX 287 /* 288 * Copy VSX low doubleword to local buffer for formatting, 289 * then out to userspace. Update v_regs to point after the 290 * VMX data. 291 */ 292 if (tsk->thread.used_vsr) { 293 v_regs += ELF_NVRREG; 294 tm_v_regs += ELF_NVRREG; 295 296 err |= copy_ckvsx_to_user(v_regs, tsk); 297 298 if (msr & MSR_VSX) 299 err |= copy_vsx_to_user(tm_v_regs, tsk); 300 else 301 err |= copy_ckvsx_to_user(tm_v_regs, tsk); 302 303 /* set MSR_VSX in the MSR value in the frame to 304 * indicate that sc->vs_reg) contains valid data. 305 */ 306 msr |= MSR_VSX; 307 } 308 #endif /* CONFIG_VSX */ 309 310 err |= __put_user(&sc->gp_regs, &sc->regs); 311 err |= __put_user(&tm_sc->gp_regs, &tm_sc->regs); 312 WARN_ON(!FULL_REGS(regs)); 313 err |= __copy_to_user(&tm_sc->gp_regs, regs, GP_REGS_SIZE); 314 err |= __copy_to_user(&sc->gp_regs, 315 &tsk->thread.ckpt_regs, GP_REGS_SIZE); 316 err |= __put_user(msr, &tm_sc->gp_regs[PT_MSR]); 317 err |= __put_user(msr, &sc->gp_regs[PT_MSR]); 318 err |= __put_user(signr, &sc->signal); 319 err |= __put_user(handler, &sc->handler); 320 if (set != NULL) 321 err |= __put_user(set->sig[0], &sc->oldmask); 322 323 return err; 324 } 325 #endif 326 327 /* 328 * Restore the sigcontext from the signal frame. 329 */ 330 #define unsafe_restore_sigcontext(tsk, set, sig, sc, label) do { \ 331 if (__unsafe_restore_sigcontext(tsk, set, sig, sc)) \ 332 goto label; \ 333 } while (0) 334 static long notrace __unsafe_restore_sigcontext(struct task_struct *tsk, sigset_t *set, 335 int sig, struct sigcontext __user *sc) 336 { 337 #ifdef CONFIG_ALTIVEC 338 elf_vrreg_t __user *v_regs; 339 #endif 340 unsigned long save_r13 = 0; 341 unsigned long msr; 342 struct pt_regs *regs = tsk->thread.regs; 343 #ifdef CONFIG_VSX 344 int i; 345 #endif 346 347 BUG_ON(tsk != current); 348 349 /* If this is not a signal return, we preserve the TLS in r13 */ 350 if (!sig) 351 save_r13 = regs->gpr[13]; 352 353 /* copy the GPRs */ 354 unsafe_copy_from_user(regs->gpr, sc->gp_regs, sizeof(regs->gpr), efault_out); 355 unsafe_get_user(regs->nip, &sc->gp_regs[PT_NIP], efault_out); 356 /* get MSR separately, transfer the LE bit if doing signal return */ 357 unsafe_get_user(msr, &sc->gp_regs[PT_MSR], efault_out); 358 if (sig) 359 regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE); 360 unsafe_get_user(regs->orig_gpr3, &sc->gp_regs[PT_ORIG_R3], efault_out); 361 unsafe_get_user(regs->ctr, &sc->gp_regs[PT_CTR], efault_out); 362 unsafe_get_user(regs->link, &sc->gp_regs[PT_LNK], efault_out); 363 unsafe_get_user(regs->xer, &sc->gp_regs[PT_XER], efault_out); 364 unsafe_get_user(regs->ccr, &sc->gp_regs[PT_CCR], efault_out); 365 /* Don't allow userspace to set SOFTE */ 366 set_trap_norestart(regs); 367 unsafe_get_user(regs->dar, &sc->gp_regs[PT_DAR], efault_out); 368 unsafe_get_user(regs->dsisr, &sc->gp_regs[PT_DSISR], efault_out); 369 unsafe_get_user(regs->result, &sc->gp_regs[PT_RESULT], efault_out); 370 371 if (!sig) 372 regs->gpr[13] = save_r13; 373 if (set != NULL) 374 unsafe_get_user(set->sig[0], &sc->oldmask, efault_out); 375 376 /* 377 * Force reload of FP/VEC. 378 * This has to be done before copying stuff into tsk->thread.fpr/vr 379 * for the reasons explained in the previous comment. 380 */ 381 regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX); 382 383 #ifdef CONFIG_ALTIVEC 384 unsafe_get_user(v_regs, &sc->v_regs, efault_out); 385 if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128))) 386 return -EFAULT; 387 /* Copy 33 vec registers (vr0..31 and vscr) from the stack */ 388 if (v_regs != NULL && (msr & MSR_VEC) != 0) { 389 unsafe_copy_from_user(&tsk->thread.vr_state, v_regs, 390 33 * sizeof(vector128), efault_out); 391 tsk->thread.used_vr = true; 392 } else if (tsk->thread.used_vr) { 393 memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128)); 394 } 395 /* Always get VRSAVE back */ 396 if (v_regs != NULL) 397 unsafe_get_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33], efault_out); 398 else 399 tsk->thread.vrsave = 0; 400 if (cpu_has_feature(CPU_FTR_ALTIVEC)) 401 mtspr(SPRN_VRSAVE, tsk->thread.vrsave); 402 #endif /* CONFIG_ALTIVEC */ 403 /* restore floating point */ 404 unsafe_copy_fpr_from_user(tsk, &sc->fp_regs, efault_out); 405 #ifdef CONFIG_VSX 406 /* 407 * Get additional VSX data. Update v_regs to point after the 408 * VMX data. Copy VSX low doubleword from userspace to local 409 * buffer for formatting, then into the taskstruct. 410 */ 411 v_regs += ELF_NVRREG; 412 if ((msr & MSR_VSX) != 0) { 413 unsafe_copy_vsx_from_user(tsk, v_regs, efault_out); 414 tsk->thread.used_vsr = true; 415 } else { 416 for (i = 0; i < 32 ; i++) 417 tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0; 418 } 419 #endif 420 return 0; 421 422 efault_out: 423 return -EFAULT; 424 } 425 426 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM 427 /* 428 * Restore the two sigcontexts from the frame of a transactional processes. 429 */ 430 431 static long restore_tm_sigcontexts(struct task_struct *tsk, 432 struct sigcontext __user *sc, 433 struct sigcontext __user *tm_sc) 434 { 435 #ifdef CONFIG_ALTIVEC 436 elf_vrreg_t __user *v_regs, *tm_v_regs; 437 #endif 438 unsigned long err = 0; 439 unsigned long msr; 440 struct pt_regs *regs = tsk->thread.regs; 441 #ifdef CONFIG_VSX 442 int i; 443 #endif 444 445 BUG_ON(tsk != current); 446 447 if (tm_suspend_disabled) 448 return -EINVAL; 449 450 /* copy the GPRs */ 451 err |= __copy_from_user(regs->gpr, tm_sc->gp_regs, sizeof(regs->gpr)); 452 err |= __copy_from_user(&tsk->thread.ckpt_regs, sc->gp_regs, 453 sizeof(regs->gpr)); 454 455 /* 456 * TFHAR is restored from the checkpointed 'wound-back' ucontext's NIP. 457 * TEXASR was set by the signal delivery reclaim, as was TFIAR. 458 * Users doing anything abhorrent like thread-switching w/ signals for 459 * TM-Suspended code will have to back TEXASR/TFIAR up themselves. 460 * For the case of getting a signal and simply returning from it, 461 * we don't need to re-copy them here. 462 */ 463 err |= __get_user(regs->nip, &tm_sc->gp_regs[PT_NIP]); 464 err |= __get_user(tsk->thread.tm_tfhar, &sc->gp_regs[PT_NIP]); 465 466 /* get MSR separately, transfer the LE bit if doing signal return */ 467 err |= __get_user(msr, &sc->gp_regs[PT_MSR]); 468 /* Don't allow reserved mode. */ 469 if (MSR_TM_RESV(msr)) 470 return -EINVAL; 471 472 /* pull in MSR LE from user context */ 473 regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE); 474 475 /* The following non-GPR non-FPR non-VR state is also checkpointed: */ 476 err |= __get_user(regs->ctr, &tm_sc->gp_regs[PT_CTR]); 477 err |= __get_user(regs->link, &tm_sc->gp_regs[PT_LNK]); 478 err |= __get_user(regs->xer, &tm_sc->gp_regs[PT_XER]); 479 err |= __get_user(regs->ccr, &tm_sc->gp_regs[PT_CCR]); 480 err |= __get_user(tsk->thread.ckpt_regs.ctr, 481 &sc->gp_regs[PT_CTR]); 482 err |= __get_user(tsk->thread.ckpt_regs.link, 483 &sc->gp_regs[PT_LNK]); 484 err |= __get_user(tsk->thread.ckpt_regs.xer, 485 &sc->gp_regs[PT_XER]); 486 err |= __get_user(tsk->thread.ckpt_regs.ccr, 487 &sc->gp_regs[PT_CCR]); 488 /* Don't allow userspace to set SOFTE */ 489 set_trap_norestart(regs); 490 /* These regs are not checkpointed; they can go in 'regs'. */ 491 err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]); 492 err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]); 493 err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]); 494 495 /* 496 * Force reload of FP/VEC. 497 * This has to be done before copying stuff into tsk->thread.fpr/vr 498 * for the reasons explained in the previous comment. 499 */ 500 regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX); 501 502 #ifdef CONFIG_ALTIVEC 503 err |= __get_user(v_regs, &sc->v_regs); 504 err |= __get_user(tm_v_regs, &tm_sc->v_regs); 505 if (err) 506 return err; 507 if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128))) 508 return -EFAULT; 509 if (tm_v_regs && !access_ok(tm_v_regs, 34 * sizeof(vector128))) 510 return -EFAULT; 511 /* Copy 33 vec registers (vr0..31 and vscr) from the stack */ 512 if (v_regs != NULL && tm_v_regs != NULL && (msr & MSR_VEC) != 0) { 513 err |= __copy_from_user(&tsk->thread.ckvr_state, v_regs, 514 33 * sizeof(vector128)); 515 err |= __copy_from_user(&tsk->thread.vr_state, tm_v_regs, 516 33 * sizeof(vector128)); 517 current->thread.used_vr = true; 518 } 519 else if (tsk->thread.used_vr) { 520 memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128)); 521 memset(&tsk->thread.ckvr_state, 0, 33 * sizeof(vector128)); 522 } 523 /* Always get VRSAVE back */ 524 if (v_regs != NULL && tm_v_regs != NULL) { 525 err |= __get_user(tsk->thread.ckvrsave, 526 (u32 __user *)&v_regs[33]); 527 err |= __get_user(tsk->thread.vrsave, 528 (u32 __user *)&tm_v_regs[33]); 529 } 530 else { 531 tsk->thread.vrsave = 0; 532 tsk->thread.ckvrsave = 0; 533 } 534 if (cpu_has_feature(CPU_FTR_ALTIVEC)) 535 mtspr(SPRN_VRSAVE, tsk->thread.vrsave); 536 #endif /* CONFIG_ALTIVEC */ 537 /* restore floating point */ 538 err |= copy_fpr_from_user(tsk, &tm_sc->fp_regs); 539 err |= copy_ckfpr_from_user(tsk, &sc->fp_regs); 540 #ifdef CONFIG_VSX 541 /* 542 * Get additional VSX data. Update v_regs to point after the 543 * VMX data. Copy VSX low doubleword from userspace to local 544 * buffer for formatting, then into the taskstruct. 545 */ 546 if (v_regs && ((msr & MSR_VSX) != 0)) { 547 v_regs += ELF_NVRREG; 548 tm_v_regs += ELF_NVRREG; 549 err |= copy_vsx_from_user(tsk, tm_v_regs); 550 err |= copy_ckvsx_from_user(tsk, v_regs); 551 tsk->thread.used_vsr = true; 552 } else { 553 for (i = 0; i < 32 ; i++) { 554 tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0; 555 tsk->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET] = 0; 556 } 557 } 558 #endif 559 tm_enable(); 560 /* Make sure the transaction is marked as failed */ 561 tsk->thread.tm_texasr |= TEXASR_FS; 562 563 /* 564 * Disabling preemption, since it is unsafe to be preempted 565 * with MSR[TS] set without recheckpointing. 566 */ 567 preempt_disable(); 568 569 /* pull in MSR TS bits from user context */ 570 regs->msr |= msr & MSR_TS_MASK; 571 572 /* 573 * Ensure that TM is enabled in regs->msr before we leave the signal 574 * handler. It could be the case that (a) user disabled the TM bit 575 * through the manipulation of the MSR bits in uc_mcontext or (b) the 576 * TM bit was disabled because a sufficient number of context switches 577 * happened whilst in the signal handler and load_tm overflowed, 578 * disabling the TM bit. In either case we can end up with an illegal 579 * TM state leading to a TM Bad Thing when we return to userspace. 580 * 581 * CAUTION: 582 * After regs->MSR[TS] being updated, make sure that get_user(), 583 * put_user() or similar functions are *not* called. These 584 * functions can generate page faults which will cause the process 585 * to be de-scheduled with MSR[TS] set but without calling 586 * tm_recheckpoint(). This can cause a bug. 587 */ 588 regs->msr |= MSR_TM; 589 590 /* This loads the checkpointed FP/VEC state, if used */ 591 tm_recheckpoint(&tsk->thread); 592 593 msr_check_and_set(msr & (MSR_FP | MSR_VEC)); 594 if (msr & MSR_FP) { 595 load_fp_state(&tsk->thread.fp_state); 596 regs->msr |= (MSR_FP | tsk->thread.fpexc_mode); 597 } 598 if (msr & MSR_VEC) { 599 load_vr_state(&tsk->thread.vr_state); 600 regs->msr |= MSR_VEC; 601 } 602 603 preempt_enable(); 604 605 return err; 606 } 607 #else /* !CONFIG_PPC_TRANSACTIONAL_MEM */ 608 static long restore_tm_sigcontexts(struct task_struct *tsk, struct sigcontext __user *sc, 609 struct sigcontext __user *tm_sc) 610 { 611 return -EINVAL; 612 } 613 #endif 614 615 /* 616 * Setup the trampoline code on the stack 617 */ 618 static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp) 619 { 620 int i; 621 long err = 0; 622 623 /* bctrl # call the handler */ 624 err |= __put_user(PPC_INST_BCTRL, &tramp[0]); 625 /* addi r1, r1, __SIGNAL_FRAMESIZE # Pop the dummy stackframe */ 626 err |= __put_user(PPC_INST_ADDI | __PPC_RT(R1) | __PPC_RA(R1) | 627 (__SIGNAL_FRAMESIZE & 0xffff), &tramp[1]); 628 /* li r0, __NR_[rt_]sigreturn| */ 629 err |= __put_user(PPC_INST_ADDI | (syscall & 0xffff), &tramp[2]); 630 /* sc */ 631 err |= __put_user(PPC_INST_SC, &tramp[3]); 632 633 /* Minimal traceback info */ 634 for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++) 635 err |= __put_user(0, &tramp[i]); 636 637 if (!err) 638 flush_icache_range((unsigned long) &tramp[0], 639 (unsigned long) &tramp[TRAMP_SIZE]); 640 641 return err; 642 } 643 644 /* 645 * Userspace code may pass a ucontext which doesn't include VSX added 646 * at the end. We need to check for this case. 647 */ 648 #define UCONTEXTSIZEWITHOUTVSX \ 649 (sizeof(struct ucontext) - 32*sizeof(long)) 650 651 /* 652 * Handle {get,set,swap}_context operations 653 */ 654 SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx, 655 struct ucontext __user *, new_ctx, long, ctx_size) 656 { 657 sigset_t set; 658 unsigned long new_msr = 0; 659 int ctx_has_vsx_region = 0; 660 661 if (new_ctx && 662 get_user(new_msr, &new_ctx->uc_mcontext.gp_regs[PT_MSR])) 663 return -EFAULT; 664 /* 665 * Check that the context is not smaller than the original 666 * size (with VMX but without VSX) 667 */ 668 if (ctx_size < UCONTEXTSIZEWITHOUTVSX) 669 return -EINVAL; 670 /* 671 * If the new context state sets the MSR VSX bits but 672 * it doesn't provide VSX state. 673 */ 674 if ((ctx_size < sizeof(struct ucontext)) && 675 (new_msr & MSR_VSX)) 676 return -EINVAL; 677 /* Does the context have enough room to store VSX data? */ 678 if (ctx_size >= sizeof(struct ucontext)) 679 ctx_has_vsx_region = 1; 680 681 if (old_ctx != NULL) { 682 prepare_setup_sigcontext(current); 683 if (!user_write_access_begin(old_ctx, ctx_size)) 684 return -EFAULT; 685 686 unsafe_setup_sigcontext(&old_ctx->uc_mcontext, current, 0, NULL, 687 0, ctx_has_vsx_region, efault_out); 688 unsafe_copy_to_user(&old_ctx->uc_sigmask, ¤t->blocked, 689 sizeof(sigset_t), efault_out); 690 691 user_write_access_end(); 692 } 693 if (new_ctx == NULL) 694 return 0; 695 if (!access_ok(new_ctx, ctx_size) || 696 fault_in_pages_readable((u8 __user *)new_ctx, ctx_size)) 697 return -EFAULT; 698 699 /* 700 * If we get a fault copying the context into the kernel's 701 * image of the user's registers, we can't just return -EFAULT 702 * because the user's registers will be corrupted. For instance 703 * the NIP value may have been updated but not some of the 704 * other registers. Given that we have done the access_ok 705 * and successfully read the first and last bytes of the region 706 * above, this should only happen in an out-of-memory situation 707 * or if another thread unmaps the region containing the context. 708 * We kill the task with a SIGSEGV in this situation. 709 */ 710 711 if (__copy_from_user(&set, &new_ctx->uc_sigmask, sizeof(set))) 712 do_exit(SIGSEGV); 713 set_current_blocked(&set); 714 715 if (!user_read_access_begin(new_ctx, ctx_size)) 716 return -EFAULT; 717 if (__unsafe_restore_sigcontext(current, NULL, 0, &new_ctx->uc_mcontext)) { 718 user_read_access_end(); 719 do_exit(SIGSEGV); 720 } 721 user_read_access_end(); 722 723 /* This returns like rt_sigreturn */ 724 set_thread_flag(TIF_RESTOREALL); 725 return 0; 726 727 efault_out: 728 user_write_access_end(); 729 return -EFAULT; 730 } 731 732 733 /* 734 * Do a signal return; undo the signal stack. 735 */ 736 737 SYSCALL_DEFINE0(rt_sigreturn) 738 { 739 struct pt_regs *regs = current_pt_regs(); 740 struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1]; 741 sigset_t set; 742 unsigned long msr; 743 744 /* Always make any pending restarted system calls return -EINTR */ 745 current->restart_block.fn = do_no_restart_syscall; 746 747 if (!access_ok(uc, sizeof(*uc))) 748 goto badframe; 749 750 if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set))) 751 goto badframe; 752 set_current_blocked(&set); 753 754 if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM)) { 755 /* 756 * If there is a transactional state then throw it away. 757 * The purpose of a sigreturn is to destroy all traces of the 758 * signal frame, this includes any transactional state created 759 * within in. We only check for suspended as we can never be 760 * active in the kernel, we are active, there is nothing better to 761 * do than go ahead and Bad Thing later. 762 * The cause is not important as there will never be a 763 * recheckpoint so it's not user visible. 764 */ 765 if (MSR_TM_SUSPENDED(mfmsr())) 766 tm_reclaim_current(0); 767 768 /* 769 * Disable MSR[TS] bit also, so, if there is an exception in the 770 * code below (as a page fault in copy_ckvsx_to_user()), it does 771 * not recheckpoint this task if there was a context switch inside 772 * the exception. 773 * 774 * A major page fault can indirectly call schedule(). A reschedule 775 * process in the middle of an exception can have a side effect 776 * (Changing the CPU MSR[TS] state), since schedule() is called 777 * with the CPU MSR[TS] disable and returns with MSR[TS]=Suspended 778 * (switch_to() calls tm_recheckpoint() for the 'new' process). In 779 * this case, the process continues to be the same in the CPU, but 780 * the CPU state just changed. 781 * 782 * This can cause a TM Bad Thing, since the MSR in the stack will 783 * have the MSR[TS]=0, and this is what will be used to RFID. 784 * 785 * Clearing MSR[TS] state here will avoid a recheckpoint if there 786 * is any process reschedule in kernel space. The MSR[TS] state 787 * does not need to be saved also, since it will be replaced with 788 * the MSR[TS] that came from user context later, at 789 * restore_tm_sigcontexts. 790 */ 791 regs->msr &= ~MSR_TS_MASK; 792 793 if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR])) 794 goto badframe; 795 } 796 797 if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM) && MSR_TM_ACTIVE(msr)) { 798 /* We recheckpoint on return. */ 799 struct ucontext __user *uc_transact; 800 801 /* Trying to start TM on non TM system */ 802 if (!cpu_has_feature(CPU_FTR_TM)) 803 goto badframe; 804 805 if (__get_user(uc_transact, &uc->uc_link)) 806 goto badframe; 807 if (restore_tm_sigcontexts(current, &uc->uc_mcontext, 808 &uc_transact->uc_mcontext)) 809 goto badframe; 810 } else { 811 /* 812 * Fall through, for non-TM restore 813 * 814 * Unset MSR[TS] on the thread regs since MSR from user 815 * context does not have MSR active, and recheckpoint was 816 * not called since restore_tm_sigcontexts() was not called 817 * also. 818 * 819 * If not unsetting it, the code can RFID to userspace with 820 * MSR[TS] set, but without CPU in the proper state, 821 * causing a TM bad thing. 822 */ 823 current->thread.regs->msr &= ~MSR_TS_MASK; 824 if (!user_read_access_begin(&uc->uc_mcontext, sizeof(uc->uc_mcontext))) 825 return -EFAULT; 826 if (__unsafe_restore_sigcontext(current, NULL, 1, &uc->uc_mcontext)) { 827 user_read_access_end(); 828 goto badframe; 829 } 830 user_read_access_end(); 831 } 832 833 if (restore_altstack(&uc->uc_stack)) 834 goto badframe; 835 836 set_thread_flag(TIF_RESTOREALL); 837 return 0; 838 839 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 /* Make sure signal handler doesn't get spurious FP exceptions */ 906 tsk->thread.fp_state.fpscr = 0; 907 908 /* Set up to return from userspace. */ 909 if (tsk->mm->context.vdso) { 910 regs->nip = VDSO64_SYMBOL(tsk->mm->context.vdso, sigtramp_rt64); 911 } else { 912 err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]); 913 if (err) 914 goto badframe; 915 regs->nip = (unsigned long) &frame->tramp[0]; 916 } 917 918 919 /* Save the siginfo outside of the unsafe block. */ 920 if (copy_siginfo_to_user(&frame->info, &ksig->info)) 921 goto badframe; 922 923 /* Allocate a dummy caller frame for the signal handler. */ 924 newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE; 925 err |= put_user(regs->gpr[1], (unsigned long __user *)newsp); 926 927 /* Set up "regs" so we "return" to the signal handler. */ 928 if (is_elf2_task()) { 929 regs->ctr = (unsigned long) ksig->ka.sa.sa_handler; 930 regs->gpr[12] = regs->ctr; 931 } else { 932 /* Handler is *really* a pointer to the function descriptor for 933 * the signal routine. The first entry in the function 934 * descriptor is the entry address of signal and the second 935 * entry is the TOC value we need to use. 936 */ 937 func_descr_t __user *funct_desc_ptr = 938 (func_descr_t __user *) ksig->ka.sa.sa_handler; 939 940 err |= get_user(regs->ctr, &funct_desc_ptr->entry); 941 err |= get_user(regs->gpr[2], &funct_desc_ptr->toc); 942 } 943 944 /* enter the signal handler in native-endian mode */ 945 regs->msr &= ~MSR_LE; 946 regs->msr |= (MSR_KERNEL & MSR_LE); 947 regs->gpr[1] = newsp; 948 regs->gpr[3] = ksig->sig; 949 regs->result = 0; 950 if (ksig->ka.sa.sa_flags & SA_SIGINFO) { 951 err |= get_user(regs->gpr[4], (unsigned long __user *)&frame->pinfo); 952 err |= get_user(regs->gpr[5], (unsigned long __user *)&frame->puc); 953 regs->gpr[6] = (unsigned long) frame; 954 } else { 955 regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext; 956 } 957 if (err) 958 goto badframe; 959 960 return 0; 961 962 badframe_block: 963 user_write_access_end(); 964 badframe: 965 signal_fault(current, regs, "handle_rt_signal64", frame); 966 967 return 1; 968 } 969