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 unsigned long get_min_sigframe_size_64(void) 70 { 71 return sizeof(struct rt_sigframe) + __SIGNAL_FRAMESIZE; 72 } 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 static void prepare_setup_sigcontext(struct task_struct *tsk) 88 { 89 #ifdef CONFIG_ALTIVEC 90 /* save altivec registers */ 91 if (tsk->thread.used_vr) 92 flush_altivec_to_thread(tsk); 93 if (cpu_has_feature(CPU_FTR_ALTIVEC)) 94 tsk->thread.vrsave = mfspr(SPRN_VRSAVE); 95 #endif /* CONFIG_ALTIVEC */ 96 97 flush_fp_to_thread(tsk); 98 99 #ifdef CONFIG_VSX 100 if (tsk->thread.used_vsr) 101 flush_vsx_to_thread(tsk); 102 #endif /* CONFIG_VSX */ 103 } 104 105 /* 106 * Set up the sigcontext for the signal frame. 107 */ 108 109 #define unsafe_setup_sigcontext(sc, tsk, signr, set, handler, ctx_has_vsx_region, label)\ 110 do { \ 111 if (__unsafe_setup_sigcontext(sc, tsk, signr, set, handler, ctx_has_vsx_region))\ 112 goto label; \ 113 } while (0) 114 static long notrace __unsafe_setup_sigcontext(struct sigcontext __user *sc, 115 struct task_struct *tsk, int signr, sigset_t *set, 116 unsigned long handler, int ctx_has_vsx_region) 117 { 118 /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the 119 * process never used altivec yet (MSR_VEC is zero in pt_regs of 120 * the context). This is very important because we must ensure we 121 * don't lose the VRSAVE content that may have been set prior to 122 * the process doing its first vector operation 123 * Userland shall check AT_HWCAP to know whether it can rely on the 124 * v_regs pointer or not 125 */ 126 #ifdef CONFIG_ALTIVEC 127 elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc); 128 #endif 129 struct pt_regs *regs = tsk->thread.regs; 130 unsigned long msr = regs->msr; 131 /* Force usr to always see softe as 1 (interrupts enabled) */ 132 unsigned long softe = 0x1; 133 134 BUG_ON(tsk != current); 135 136 #ifdef CONFIG_ALTIVEC 137 unsafe_put_user(v_regs, &sc->v_regs, efault_out); 138 139 /* save altivec registers */ 140 if (tsk->thread.used_vr) { 141 /* Copy 33 vec registers (vr0..31 and vscr) to the stack */ 142 unsafe_copy_to_user(v_regs, &tsk->thread.vr_state, 143 33 * sizeof(vector128), efault_out); 144 /* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg) 145 * contains valid data. 146 */ 147 msr |= MSR_VEC; 148 } 149 /* We always copy to/from vrsave, it's 0 if we don't have or don't 150 * use altivec. 151 */ 152 unsafe_put_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33], efault_out); 153 #else /* CONFIG_ALTIVEC */ 154 unsafe_put_user(0, &sc->v_regs, efault_out); 155 #endif /* CONFIG_ALTIVEC */ 156 /* copy fpr regs and fpscr */ 157 unsafe_copy_fpr_to_user(&sc->fp_regs, tsk, efault_out); 158 159 /* 160 * Clear the MSR VSX bit to indicate there is no valid state attached 161 * to this context, except in the specific case below where we set it. 162 */ 163 msr &= ~MSR_VSX; 164 #ifdef CONFIG_VSX 165 /* 166 * Copy VSX low doubleword to local buffer for formatting, 167 * then out to userspace. Update v_regs to point after the 168 * VMX data. 169 */ 170 if (tsk->thread.used_vsr && ctx_has_vsx_region) { 171 v_regs += ELF_NVRREG; 172 unsafe_copy_vsx_to_user(v_regs, tsk, efault_out); 173 /* set MSR_VSX in the MSR value in the frame to 174 * indicate that sc->vs_reg) contains valid data. 175 */ 176 msr |= MSR_VSX; 177 } 178 #endif /* CONFIG_VSX */ 179 unsafe_put_user(&sc->gp_regs, &sc->regs, efault_out); 180 unsafe_copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE, efault_out); 181 unsafe_put_user(msr, &sc->gp_regs[PT_MSR], efault_out); 182 unsafe_put_user(softe, &sc->gp_regs[PT_SOFTE], efault_out); 183 unsafe_put_user(signr, &sc->signal, efault_out); 184 unsafe_put_user(handler, &sc->handler, efault_out); 185 if (set != NULL) 186 unsafe_put_user(set->sig[0], &sc->oldmask, efault_out); 187 188 return 0; 189 190 efault_out: 191 return -EFAULT; 192 } 193 194 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM 195 /* 196 * As above, but Transactional Memory is in use, so deliver sigcontexts 197 * containing checkpointed and transactional register states. 198 * 199 * To do this, we treclaim (done before entering here) to gather both sets of 200 * registers and set up the 'normal' sigcontext registers with rolled-back 201 * register values such that a simple signal handler sees a correct 202 * checkpointed register state. If interested, a TM-aware sighandler can 203 * examine the transactional registers in the 2nd sigcontext to determine the 204 * real origin of the signal. 205 */ 206 static long setup_tm_sigcontexts(struct sigcontext __user *sc, 207 struct sigcontext __user *tm_sc, 208 struct task_struct *tsk, 209 int signr, sigset_t *set, unsigned long handler, 210 unsigned long msr) 211 { 212 /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the 213 * process never used altivec yet (MSR_VEC is zero in pt_regs of 214 * the context). This is very important because we must ensure we 215 * don't lose the VRSAVE content that may have been set prior to 216 * the process doing its first vector operation 217 * Userland shall check AT_HWCAP to know wether it can rely on the 218 * v_regs pointer or not. 219 */ 220 #ifdef CONFIG_ALTIVEC 221 elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc); 222 elf_vrreg_t __user *tm_v_regs = sigcontext_vmx_regs(tm_sc); 223 #endif 224 struct pt_regs *regs = tsk->thread.regs; 225 long err = 0; 226 227 BUG_ON(tsk != current); 228 229 BUG_ON(!MSR_TM_ACTIVE(msr)); 230 231 WARN_ON(tm_suspend_disabled); 232 233 /* Restore checkpointed FP, VEC, and VSX bits from ckpt_regs as 234 * it contains the correct FP, VEC, VSX state after we treclaimed 235 * the transaction and giveup_all() was called on reclaiming. 236 */ 237 msr |= tsk->thread.ckpt_regs.msr & (MSR_FP | MSR_VEC | MSR_VSX); 238 239 #ifdef CONFIG_ALTIVEC 240 err |= __put_user(v_regs, &sc->v_regs); 241 err |= __put_user(tm_v_regs, &tm_sc->v_regs); 242 243 /* save altivec registers */ 244 if (tsk->thread.used_vr) { 245 /* Copy 33 vec registers (vr0..31 and vscr) to the stack */ 246 err |= __copy_to_user(v_regs, &tsk->thread.ckvr_state, 247 33 * sizeof(vector128)); 248 /* If VEC was enabled there are transactional VRs valid too, 249 * else they're a copy of the checkpointed VRs. 250 */ 251 if (msr & MSR_VEC) 252 err |= __copy_to_user(tm_v_regs, 253 &tsk->thread.vr_state, 254 33 * sizeof(vector128)); 255 else 256 err |= __copy_to_user(tm_v_regs, 257 &tsk->thread.ckvr_state, 258 33 * sizeof(vector128)); 259 260 /* set MSR_VEC in the MSR value in the frame to indicate 261 * that sc->v_reg contains valid data. 262 */ 263 msr |= MSR_VEC; 264 } 265 /* We always copy to/from vrsave, it's 0 if we don't have or don't 266 * use altivec. 267 */ 268 if (cpu_has_feature(CPU_FTR_ALTIVEC)) 269 tsk->thread.ckvrsave = mfspr(SPRN_VRSAVE); 270 err |= __put_user(tsk->thread.ckvrsave, (u32 __user *)&v_regs[33]); 271 if (msr & MSR_VEC) 272 err |= __put_user(tsk->thread.vrsave, 273 (u32 __user *)&tm_v_regs[33]); 274 else 275 err |= __put_user(tsk->thread.ckvrsave, 276 (u32 __user *)&tm_v_regs[33]); 277 278 #else /* CONFIG_ALTIVEC */ 279 err |= __put_user(0, &sc->v_regs); 280 err |= __put_user(0, &tm_sc->v_regs); 281 #endif /* CONFIG_ALTIVEC */ 282 283 /* copy fpr regs and fpscr */ 284 err |= copy_ckfpr_to_user(&sc->fp_regs, tsk); 285 if (msr & MSR_FP) 286 err |= copy_fpr_to_user(&tm_sc->fp_regs, tsk); 287 else 288 err |= copy_ckfpr_to_user(&tm_sc->fp_regs, tsk); 289 290 #ifdef CONFIG_VSX 291 /* 292 * Copy VSX low doubleword to local buffer for formatting, 293 * then out to userspace. Update v_regs to point after the 294 * VMX data. 295 */ 296 if (tsk->thread.used_vsr) { 297 v_regs += ELF_NVRREG; 298 tm_v_regs += ELF_NVRREG; 299 300 err |= copy_ckvsx_to_user(v_regs, tsk); 301 302 if (msr & MSR_VSX) 303 err |= copy_vsx_to_user(tm_v_regs, tsk); 304 else 305 err |= copy_ckvsx_to_user(tm_v_regs, tsk); 306 307 /* set MSR_VSX in the MSR value in the frame to 308 * indicate that sc->vs_reg) contains valid data. 309 */ 310 msr |= MSR_VSX; 311 } 312 #endif /* CONFIG_VSX */ 313 314 err |= __put_user(&sc->gp_regs, &sc->regs); 315 err |= __put_user(&tm_sc->gp_regs, &tm_sc->regs); 316 err |= __copy_to_user(&tm_sc->gp_regs, regs, GP_REGS_SIZE); 317 err |= __copy_to_user(&sc->gp_regs, 318 &tsk->thread.ckpt_regs, GP_REGS_SIZE); 319 err |= __put_user(msr, &tm_sc->gp_regs[PT_MSR]); 320 err |= __put_user(msr, &sc->gp_regs[PT_MSR]); 321 err |= __put_user(signr, &sc->signal); 322 err |= __put_user(handler, &sc->handler); 323 if (set != NULL) 324 err |= __put_user(set->sig[0], &sc->oldmask); 325 326 return err; 327 } 328 #endif 329 330 /* 331 * Restore the sigcontext from the signal frame. 332 */ 333 #define unsafe_restore_sigcontext(tsk, set, sig, sc, label) do { \ 334 if (__unsafe_restore_sigcontext(tsk, set, sig, sc)) \ 335 goto label; \ 336 } while (0) 337 static long notrace __unsafe_restore_sigcontext(struct task_struct *tsk, sigset_t *set, 338 int sig, struct sigcontext __user *sc) 339 { 340 #ifdef CONFIG_ALTIVEC 341 elf_vrreg_t __user *v_regs; 342 #endif 343 unsigned long save_r13 = 0; 344 unsigned long msr; 345 struct pt_regs *regs = tsk->thread.regs; 346 #ifdef CONFIG_VSX 347 int i; 348 #endif 349 350 BUG_ON(tsk != current); 351 352 /* If this is not a signal return, we preserve the TLS in r13 */ 353 if (!sig) 354 save_r13 = regs->gpr[13]; 355 356 /* copy the GPRs */ 357 unsafe_copy_from_user(regs->gpr, sc->gp_regs, sizeof(regs->gpr), efault_out); 358 unsafe_get_user(regs->nip, &sc->gp_regs[PT_NIP], efault_out); 359 /* get MSR separately, transfer the LE bit if doing signal return */ 360 unsafe_get_user(msr, &sc->gp_regs[PT_MSR], efault_out); 361 if (sig) 362 regs_set_return_msr(regs, (regs->msr & ~MSR_LE) | (msr & MSR_LE)); 363 unsafe_get_user(regs->orig_gpr3, &sc->gp_regs[PT_ORIG_R3], efault_out); 364 unsafe_get_user(regs->ctr, &sc->gp_regs[PT_CTR], efault_out); 365 unsafe_get_user(regs->link, &sc->gp_regs[PT_LNK], efault_out); 366 unsafe_get_user(regs->xer, &sc->gp_regs[PT_XER], efault_out); 367 unsafe_get_user(regs->ccr, &sc->gp_regs[PT_CCR], efault_out); 368 /* Don't allow userspace to set SOFTE */ 369 set_trap_norestart(regs); 370 unsafe_get_user(regs->dar, &sc->gp_regs[PT_DAR], efault_out); 371 unsafe_get_user(regs->dsisr, &sc->gp_regs[PT_DSISR], efault_out); 372 unsafe_get_user(regs->result, &sc->gp_regs[PT_RESULT], efault_out); 373 374 if (!sig) 375 regs->gpr[13] = save_r13; 376 if (set != NULL) 377 unsafe_get_user(set->sig[0], &sc->oldmask, efault_out); 378 379 /* 380 * Force reload of FP/VEC/VSX so userspace sees any changes. 381 * Clear these bits from the user process' MSR before copying into the 382 * thread struct. If we are rescheduled or preempted and another task 383 * uses FP/VEC/VSX, and this process has the MSR bits set, then the 384 * context switch code will save the current CPU state into the 385 * thread_struct - possibly overwriting the data we are updating here. 386 */ 387 regs_set_return_msr(regs, regs->msr & ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX)); 388 389 #ifdef CONFIG_ALTIVEC 390 unsafe_get_user(v_regs, &sc->v_regs, efault_out); 391 if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128))) 392 return -EFAULT; 393 /* Copy 33 vec registers (vr0..31 and vscr) from the stack */ 394 if (v_regs != NULL && (msr & MSR_VEC) != 0) { 395 unsafe_copy_from_user(&tsk->thread.vr_state, v_regs, 396 33 * sizeof(vector128), efault_out); 397 tsk->thread.used_vr = true; 398 } else if (tsk->thread.used_vr) { 399 memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128)); 400 } 401 /* Always get VRSAVE back */ 402 if (v_regs != NULL) 403 unsafe_get_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33], efault_out); 404 else 405 tsk->thread.vrsave = 0; 406 if (cpu_has_feature(CPU_FTR_ALTIVEC)) 407 mtspr(SPRN_VRSAVE, tsk->thread.vrsave); 408 #endif /* CONFIG_ALTIVEC */ 409 /* restore floating point */ 410 unsafe_copy_fpr_from_user(tsk, &sc->fp_regs, efault_out); 411 #ifdef CONFIG_VSX 412 /* 413 * Get additional VSX data. Update v_regs to point after the 414 * VMX data. Copy VSX low doubleword from userspace to local 415 * buffer for formatting, then into the taskstruct. 416 */ 417 v_regs += ELF_NVRREG; 418 if ((msr & MSR_VSX) != 0) { 419 unsafe_copy_vsx_from_user(tsk, v_regs, efault_out); 420 tsk->thread.used_vsr = true; 421 } else { 422 for (i = 0; i < 32 ; i++) 423 tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0; 424 } 425 #endif 426 return 0; 427 428 efault_out: 429 return -EFAULT; 430 } 431 432 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM 433 /* 434 * Restore the two sigcontexts from the frame of a transactional processes. 435 */ 436 437 static long restore_tm_sigcontexts(struct task_struct *tsk, 438 struct sigcontext __user *sc, 439 struct sigcontext __user *tm_sc) 440 { 441 #ifdef CONFIG_ALTIVEC 442 elf_vrreg_t __user *v_regs, *tm_v_regs; 443 #endif 444 unsigned long err = 0; 445 unsigned long msr; 446 struct pt_regs *regs = tsk->thread.regs; 447 #ifdef CONFIG_VSX 448 int i; 449 #endif 450 451 BUG_ON(tsk != current); 452 453 if (tm_suspend_disabled) 454 return -EINVAL; 455 456 /* copy the GPRs */ 457 err |= __copy_from_user(regs->gpr, tm_sc->gp_regs, sizeof(regs->gpr)); 458 err |= __copy_from_user(&tsk->thread.ckpt_regs, sc->gp_regs, 459 sizeof(regs->gpr)); 460 461 /* 462 * TFHAR is restored from the checkpointed 'wound-back' ucontext's NIP. 463 * TEXASR was set by the signal delivery reclaim, as was TFIAR. 464 * Users doing anything abhorrent like thread-switching w/ signals for 465 * TM-Suspended code will have to back TEXASR/TFIAR up themselves. 466 * For the case of getting a signal and simply returning from it, 467 * we don't need to re-copy them here. 468 */ 469 err |= __get_user(regs->nip, &tm_sc->gp_regs[PT_NIP]); 470 err |= __get_user(tsk->thread.tm_tfhar, &sc->gp_regs[PT_NIP]); 471 472 /* get MSR separately, transfer the LE bit if doing signal return */ 473 err |= __get_user(msr, &sc->gp_regs[PT_MSR]); 474 /* Don't allow reserved mode. */ 475 if (MSR_TM_RESV(msr)) 476 return -EINVAL; 477 478 /* pull in MSR LE from user context */ 479 regs_set_return_msr(regs, (regs->msr & ~MSR_LE) | (msr & MSR_LE)); 480 481 /* The following non-GPR non-FPR non-VR state is also checkpointed: */ 482 err |= __get_user(regs->ctr, &tm_sc->gp_regs[PT_CTR]); 483 err |= __get_user(regs->link, &tm_sc->gp_regs[PT_LNK]); 484 err |= __get_user(regs->xer, &tm_sc->gp_regs[PT_XER]); 485 err |= __get_user(regs->ccr, &tm_sc->gp_regs[PT_CCR]); 486 err |= __get_user(tsk->thread.ckpt_regs.ctr, 487 &sc->gp_regs[PT_CTR]); 488 err |= __get_user(tsk->thread.ckpt_regs.link, 489 &sc->gp_regs[PT_LNK]); 490 err |= __get_user(tsk->thread.ckpt_regs.xer, 491 &sc->gp_regs[PT_XER]); 492 err |= __get_user(tsk->thread.ckpt_regs.ccr, 493 &sc->gp_regs[PT_CCR]); 494 /* Don't allow userspace to set SOFTE */ 495 set_trap_norestart(regs); 496 /* These regs are not checkpointed; they can go in 'regs'. */ 497 err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]); 498 err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]); 499 err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]); 500 501 /* 502 * Force reload of FP/VEC. 503 * This has to be done before copying stuff into tsk->thread.fpr/vr 504 * for the reasons explained in the previous comment. 505 */ 506 regs_set_return_msr(regs, regs->msr & ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX)); 507 508 #ifdef CONFIG_ALTIVEC 509 err |= __get_user(v_regs, &sc->v_regs); 510 err |= __get_user(tm_v_regs, &tm_sc->v_regs); 511 if (err) 512 return err; 513 if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128))) 514 return -EFAULT; 515 if (tm_v_regs && !access_ok(tm_v_regs, 34 * sizeof(vector128))) 516 return -EFAULT; 517 /* Copy 33 vec registers (vr0..31 and vscr) from the stack */ 518 if (v_regs != NULL && tm_v_regs != NULL && (msr & MSR_VEC) != 0) { 519 err |= __copy_from_user(&tsk->thread.ckvr_state, v_regs, 520 33 * sizeof(vector128)); 521 err |= __copy_from_user(&tsk->thread.vr_state, tm_v_regs, 522 33 * sizeof(vector128)); 523 current->thread.used_vr = true; 524 } 525 else if (tsk->thread.used_vr) { 526 memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128)); 527 memset(&tsk->thread.ckvr_state, 0, 33 * sizeof(vector128)); 528 } 529 /* Always get VRSAVE back */ 530 if (v_regs != NULL && tm_v_regs != NULL) { 531 err |= __get_user(tsk->thread.ckvrsave, 532 (u32 __user *)&v_regs[33]); 533 err |= __get_user(tsk->thread.vrsave, 534 (u32 __user *)&tm_v_regs[33]); 535 } 536 else { 537 tsk->thread.vrsave = 0; 538 tsk->thread.ckvrsave = 0; 539 } 540 if (cpu_has_feature(CPU_FTR_ALTIVEC)) 541 mtspr(SPRN_VRSAVE, tsk->thread.vrsave); 542 #endif /* CONFIG_ALTIVEC */ 543 /* restore floating point */ 544 err |= copy_fpr_from_user(tsk, &tm_sc->fp_regs); 545 err |= copy_ckfpr_from_user(tsk, &sc->fp_regs); 546 #ifdef CONFIG_VSX 547 /* 548 * Get additional VSX data. Update v_regs to point after the 549 * VMX data. Copy VSX low doubleword from userspace to local 550 * buffer for formatting, then into the taskstruct. 551 */ 552 if (v_regs && ((msr & MSR_VSX) != 0)) { 553 v_regs += ELF_NVRREG; 554 tm_v_regs += ELF_NVRREG; 555 err |= copy_vsx_from_user(tsk, tm_v_regs); 556 err |= copy_ckvsx_from_user(tsk, v_regs); 557 tsk->thread.used_vsr = true; 558 } else { 559 for (i = 0; i < 32 ; i++) { 560 tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0; 561 tsk->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET] = 0; 562 } 563 } 564 #endif 565 tm_enable(); 566 /* Make sure the transaction is marked as failed */ 567 tsk->thread.tm_texasr |= TEXASR_FS; 568 569 /* 570 * Disabling preemption, since it is unsafe to be preempted 571 * with MSR[TS] set without recheckpointing. 572 */ 573 preempt_disable(); 574 575 /* pull in MSR TS bits from user context */ 576 regs_set_return_msr(regs, regs->msr | (msr & MSR_TS_MASK)); 577 578 /* 579 * Ensure that TM is enabled in regs->msr before we leave the signal 580 * handler. It could be the case that (a) user disabled the TM bit 581 * through the manipulation of the MSR bits in uc_mcontext or (b) the 582 * TM bit was disabled because a sufficient number of context switches 583 * happened whilst in the signal handler and load_tm overflowed, 584 * disabling the TM bit. In either case we can end up with an illegal 585 * TM state leading to a TM Bad Thing when we return to userspace. 586 * 587 * CAUTION: 588 * After regs->MSR[TS] being updated, make sure that get_user(), 589 * put_user() or similar functions are *not* called. These 590 * functions can generate page faults which will cause the process 591 * to be de-scheduled with MSR[TS] set but without calling 592 * tm_recheckpoint(). This can cause a bug. 593 */ 594 regs_set_return_msr(regs, regs->msr | MSR_TM); 595 596 /* This loads the checkpointed FP/VEC state, if used */ 597 tm_recheckpoint(&tsk->thread); 598 599 msr_check_and_set(msr & (MSR_FP | MSR_VEC)); 600 if (msr & MSR_FP) { 601 load_fp_state(&tsk->thread.fp_state); 602 regs_set_return_msr(regs, regs->msr | (MSR_FP | tsk->thread.fpexc_mode)); 603 } 604 if (msr & MSR_VEC) { 605 load_vr_state(&tsk->thread.vr_state); 606 regs_set_return_msr(regs, regs->msr | MSR_VEC); 607 } 608 609 preempt_enable(); 610 611 return err; 612 } 613 #else /* !CONFIG_PPC_TRANSACTIONAL_MEM */ 614 static long restore_tm_sigcontexts(struct task_struct *tsk, struct sigcontext __user *sc, 615 struct sigcontext __user *tm_sc) 616 { 617 return -EINVAL; 618 } 619 #endif 620 621 /* 622 * Setup the trampoline code on the stack 623 */ 624 static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp) 625 { 626 int i; 627 628 scoped_user_write_access_size(tramp, TRAMP_SIZE * sizeof(*tramp), efault) { 629 /* Call the handler and pop the dummy stackframe*/ 630 unsafe_put_user(PPC_RAW_BCTRL(), &tramp[0], efault); 631 unsafe_put_user(PPC_RAW_ADDI(_R1, _R1, __SIGNAL_FRAMESIZE), &tramp[1], efault); 632 633 unsafe_put_user(PPC_RAW_LI(_R0, syscall), &tramp[2], efault); 634 unsafe_put_user(PPC_RAW_SC(), &tramp[3], efault); 635 636 /* Minimal traceback info */ 637 for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++) 638 unsafe_put_user(0, &tramp[i], efault); 639 } 640 641 flush_icache_range((unsigned long) &tramp[0], 642 (unsigned long) &tramp[TRAMP_SIZE]); 643 644 return 0; 645 646 efault: 647 return -EFAULT; 648 } 649 650 /* 651 * Userspace code may pass a ucontext which doesn't include VSX added 652 * at the end. We need to check for this case. 653 */ 654 #define UCONTEXTSIZEWITHOUTVSX \ 655 (sizeof(struct ucontext) - 32*sizeof(long)) 656 657 /* 658 * Handle {get,set,swap}_context operations 659 */ 660 SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx, 661 struct ucontext __user *, new_ctx, long, ctx_size) 662 { 663 sigset_t set; 664 unsigned long new_msr = 0; 665 int ctx_has_vsx_region = 0; 666 667 if (new_ctx && 668 get_user(new_msr, &new_ctx->uc_mcontext.gp_regs[PT_MSR])) 669 return -EFAULT; 670 /* 671 * Check that the context is not smaller than the original 672 * size (with VMX but without VSX) 673 */ 674 if (ctx_size < UCONTEXTSIZEWITHOUTVSX) 675 return -EINVAL; 676 /* 677 * If the new context state sets the MSR VSX bits but 678 * it doesn't provide VSX state. 679 */ 680 if ((ctx_size < sizeof(struct ucontext)) && 681 (new_msr & MSR_VSX)) 682 return -EINVAL; 683 /* Does the context have enough room to store VSX data? */ 684 if (ctx_size >= sizeof(struct ucontext)) 685 ctx_has_vsx_region = 1; 686 687 if (old_ctx != NULL) { 688 prepare_setup_sigcontext(current); 689 if (!user_write_access_begin(old_ctx, ctx_size)) 690 return -EFAULT; 691 692 unsafe_setup_sigcontext(&old_ctx->uc_mcontext, current, 0, NULL, 693 0, ctx_has_vsx_region, efault_out); 694 unsafe_copy_to_user(&old_ctx->uc_sigmask, ¤t->blocked, 695 sizeof(sigset_t), efault_out); 696 697 user_write_access_end(); 698 } 699 if (new_ctx == NULL) 700 return 0; 701 if (!access_ok(new_ctx, ctx_size) || 702 fault_in_readable((char __user *)new_ctx, ctx_size)) 703 return -EFAULT; 704 705 /* 706 * If we get a fault copying the context into the kernel's 707 * image of the user's registers, we can't just return -EFAULT 708 * because the user's registers will be corrupted. For instance 709 * the NIP value may have been updated but not some of the 710 * other registers. Given that we have done the access_ok 711 * and successfully read the first and last bytes of the region 712 * above, this should only happen in an out-of-memory situation 713 * or if another thread unmaps the region containing the context. 714 * We kill the task with a SIGSEGV in this situation. 715 */ 716 717 if (get_user_sigset(&set, &new_ctx->uc_sigmask)) { 718 force_exit_sig(SIGSEGV); 719 return -EFAULT; 720 } 721 set_current_blocked(&set); 722 723 if (!user_read_access_begin(new_ctx, ctx_size)) 724 return -EFAULT; 725 if (__unsafe_restore_sigcontext(current, NULL, 0, &new_ctx->uc_mcontext)) { 726 user_read_access_end(); 727 force_exit_sig(SIGSEGV); 728 return -EFAULT; 729 } 730 user_read_access_end(); 731 732 /* This returns like rt_sigreturn */ 733 set_thread_flag(TIF_RESTOREALL); 734 735 return 0; 736 737 efault_out: 738 user_write_access_end(); 739 return -EFAULT; 740 } 741 742 743 /* 744 * Do a signal return; undo the signal stack. 745 */ 746 747 SYSCALL_DEFINE0(rt_sigreturn) 748 { 749 struct pt_regs *regs = current_pt_regs(); 750 struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1]; 751 sigset_t set; 752 unsigned long msr; 753 754 /* Always make any pending restarted system calls return -EINTR */ 755 current->restart_block.fn = do_no_restart_syscall; 756 757 if (!access_ok(uc, sizeof(*uc))) 758 goto badframe; 759 760 if (get_user_sigset(&set, &uc->uc_sigmask)) 761 goto badframe; 762 set_current_blocked(&set); 763 764 if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM)) { 765 /* 766 * If there is a transactional state then throw it away. 767 * The purpose of a sigreturn is to destroy all traces of the 768 * signal frame, this includes any transactional state created 769 * within in. We only check for suspended as we can never be 770 * active in the kernel, we are active, there is nothing better to 771 * do than go ahead and Bad Thing later. 772 * The cause is not important as there will never be a 773 * recheckpoint so it's not user visible. 774 */ 775 if (MSR_TM_SUSPENDED(mfmsr())) 776 tm_reclaim_current(0); 777 778 /* 779 * Disable MSR[TS] bit also, so, if there is an exception in the 780 * code below (as a page fault in copy_ckvsx_to_user()), it does 781 * not recheckpoint this task if there was a context switch inside 782 * the exception. 783 * 784 * A major page fault can indirectly call schedule(). A reschedule 785 * process in the middle of an exception can have a side effect 786 * (Changing the CPU MSR[TS] state), since schedule() is called 787 * with the CPU MSR[TS] disable and returns with MSR[TS]=Suspended 788 * (switch_to() calls tm_recheckpoint() for the 'new' process). In 789 * this case, the process continues to be the same in the CPU, but 790 * the CPU state just changed. 791 * 792 * This can cause a TM Bad Thing, since the MSR in the stack will 793 * have the MSR[TS]=0, and this is what will be used to RFID. 794 * 795 * Clearing MSR[TS] state here will avoid a recheckpoint if there 796 * is any process reschedule in kernel space. The MSR[TS] state 797 * does not need to be saved also, since it will be replaced with 798 * the MSR[TS] that came from user context later, at 799 * restore_tm_sigcontexts. 800 */ 801 regs_set_return_msr(regs, regs->msr & ~MSR_TS_MASK); 802 803 if (get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR])) 804 goto badframe; 805 } 806 807 if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM) && MSR_TM_ACTIVE(msr)) { 808 /* We recheckpoint on return. */ 809 struct ucontext __user *uc_transact; 810 811 /* Trying to start TM on non TM system */ 812 if (!cpu_has_feature(CPU_FTR_TM)) 813 goto badframe; 814 815 if (get_user(uc_transact, &uc->uc_link)) 816 goto badframe; 817 if (restore_tm_sigcontexts(current, &uc->uc_mcontext, 818 &uc_transact->uc_mcontext)) 819 goto badframe; 820 } else { 821 /* 822 * Fall through, for non-TM restore 823 * 824 * Unset MSR[TS] on the thread regs since MSR from user 825 * context does not have MSR active, and recheckpoint was 826 * not called since restore_tm_sigcontexts() was not called 827 * also. 828 * 829 * If not unsetting it, the code can RFID to userspace with 830 * MSR[TS] set, but without CPU in the proper state, 831 * causing a TM bad thing. 832 */ 833 regs_set_return_msr(current->thread.regs, 834 current->thread.regs->msr & ~MSR_TS_MASK); 835 if (!user_read_access_begin(&uc->uc_mcontext, sizeof(uc->uc_mcontext))) 836 goto badframe; 837 838 unsafe_restore_sigcontext(current, NULL, 1, &uc->uc_mcontext, 839 badframe_block); 840 841 user_read_access_end(); 842 } 843 844 if (restore_altstack(&uc->uc_stack)) 845 goto badframe; 846 847 set_thread_flag(TIF_RESTOREALL); 848 849 return 0; 850 851 badframe_block: 852 user_read_access_end(); 853 badframe: 854 signal_fault(current, regs, "rt_sigreturn", uc); 855 856 force_sig(SIGSEGV); 857 return 0; 858 } 859 860 int handle_rt_signal64(struct ksignal *ksig, sigset_t *set, 861 struct task_struct *tsk) 862 { 863 struct rt_sigframe __user *frame; 864 unsigned long newsp = 0; 865 long err = 0; 866 struct pt_regs *regs = tsk->thread.regs; 867 /* Save the thread's msr before get_tm_stackpointer() changes it */ 868 unsigned long msr = regs->msr; 869 870 frame = get_sigframe(ksig, tsk, sizeof(*frame), 0); 871 872 /* 873 * This only applies when calling unsafe_setup_sigcontext() and must be 874 * called before opening the uaccess window. 875 */ 876 if (!MSR_TM_ACTIVE(msr)) 877 prepare_setup_sigcontext(tsk); 878 879 if (!user_write_access_begin(frame, sizeof(*frame))) 880 goto badframe; 881 882 unsafe_put_user(&frame->info, &frame->pinfo, badframe_block); 883 unsafe_put_user(&frame->uc, &frame->puc, badframe_block); 884 885 /* Create the ucontext. */ 886 unsafe_put_user(0, &frame->uc.uc_flags, badframe_block); 887 unsafe_save_altstack(&frame->uc.uc_stack, regs->gpr[1], badframe_block); 888 889 if (MSR_TM_ACTIVE(msr)) { 890 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM 891 /* The ucontext_t passed to userland points to the second 892 * ucontext_t (for transactional state) with its uc_link ptr. 893 */ 894 unsafe_put_user(&frame->uc_transact, &frame->uc.uc_link, badframe_block); 895 896 user_write_access_end(); 897 898 err |= setup_tm_sigcontexts(&frame->uc.uc_mcontext, 899 &frame->uc_transact.uc_mcontext, 900 tsk, ksig->sig, NULL, 901 (unsigned long)ksig->ka.sa.sa_handler, 902 msr); 903 904 if (!user_write_access_begin(&frame->uc.uc_sigmask, 905 sizeof(frame->uc.uc_sigmask))) 906 goto badframe; 907 908 #endif 909 } else { 910 unsafe_put_user(0, &frame->uc.uc_link, badframe_block); 911 unsafe_setup_sigcontext(&frame->uc.uc_mcontext, tsk, ksig->sig, 912 NULL, (unsigned long)ksig->ka.sa.sa_handler, 913 1, badframe_block); 914 } 915 916 unsafe_copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set), badframe_block); 917 user_write_access_end(); 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 /* Make sure signal handler doesn't get spurious FP exceptions */ 924 tsk->thread.fp_state.fpscr = 0; 925 926 /* Set up to return from userspace. */ 927 if (tsk->mm->context.vdso) { 928 regs_set_return_ip(regs, VDSO64_SYMBOL(tsk->mm->context.vdso, sigtramp_rt64)); 929 } else { 930 err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]); 931 if (err) 932 goto badframe; 933 regs_set_return_ip(regs, (unsigned long) &frame->tramp[0]); 934 } 935 936 /* Allocate a dummy caller frame for the signal handler. */ 937 newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE; 938 err |= put_user(regs->gpr[1], (unsigned long __user *)newsp); 939 940 /* Set up "regs" so we "return" to the signal handler. */ 941 if (is_elf2_task()) { 942 regs->ctr = (unsigned long) ksig->ka.sa.sa_handler; 943 regs->gpr[12] = regs->ctr; 944 } else { 945 /* Handler is *really* a pointer to the function descriptor for 946 * the signal routine. The first entry in the function 947 * descriptor is the entry address of signal and the second 948 * entry is the TOC value we need to use. 949 */ 950 struct func_desc __user *ptr = 951 (struct func_desc __user *)ksig->ka.sa.sa_handler; 952 953 err |= get_user(regs->ctr, &ptr->addr); 954 err |= get_user(regs->gpr[2], &ptr->toc); 955 } 956 957 /* enter the signal handler in native-endian mode */ 958 regs_set_return_msr(regs, (regs->msr & ~MSR_LE) | (MSR_KERNEL & MSR_LE)); 959 regs->gpr[1] = newsp; 960 regs->gpr[3] = ksig->sig; 961 regs->result = 0; 962 if (ksig->ka.sa.sa_flags & SA_SIGINFO) { 963 regs->gpr[4] = (unsigned long)&frame->info; 964 regs->gpr[5] = (unsigned long)&frame->uc; 965 regs->gpr[6] = (unsigned long) frame; 966 } else { 967 regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext; 968 } 969 if (err) 970 goto badframe; 971 972 return 0; 973 974 badframe_block: 975 user_write_access_end(); 976 badframe: 977 signal_fault(current, regs, "handle_rt_signal64", frame); 978 979 return 1; 980 } 981