arch/powerpc/kernel/signal_64.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  PowerPC version
   4  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
   5  *
   6  *  Derived from "arch/i386/kernel/signal.c"
   7  *    Copyright (C) 1991, 1992 Linus Torvalds
   8  *    1997-11-28  Modified for POSIX.1b signals by Richard Henderson
   9  */
  10
  11 #include <linux/sched.h>
  12 #include <linux/mm.h>
  13 #include <linux/smp.h>
  14 #include <linux/kernel.h>
  15 #include <linux/signal.h>
  16 #include <linux/errno.h>
  17 #include <linux/wait.h>
  18 #include <linux/unistd.h>
  19 #include <linux/stddef.h>
  20 #include <linux/elf.h>
  21 #include <linux/ptrace.h>
  22 #include <linux/ratelimit.h>
  23 #include <linux/syscalls.h>
  24
  25 #include <asm/sigcontext.h>
  26 #include <asm/ucontext.h>
  27 #include <linux/uaccess.h>
  28 #include <asm/pgtable.h>
  29 #include <asm/unistd.h>
  30 #include <asm/cacheflush.h>
  31 #include <asm/syscalls.h>
  32 #include <asm/vdso.h>
  33 #include <asm/switch_to.h>
  34 #include <asm/tm.h>
  35 #include <asm/asm-prototypes.h>
  36
  37 #include "signal.h"
  38
  39
  40 #define GP_REGS_SIZE    min(sizeof(elf_gregset_t), sizeof(struct pt_regs))
  41 #define FP_REGS_SIZE    sizeof(elf_fpregset_t)
  42
  43 #define TRAMP_TRACEBACK 3
  44 #define TRAMP_SIZE      6
  45
  46 /*
  47  * When we have signals to deliver, we set up on the user stack,
  48  * going down from the original stack pointer:
  49  *      1) a rt_sigframe struct which contains the ucontext
  50  *      2) a gap of __SIGNAL_FRAMESIZE bytes which acts as a dummy caller
  51  *         frame for the signal handler.
  52  */
  53
  54 struct rt_sigframe {
  55         /* sys_rt_sigreturn requires the ucontext be the first field */
  56         struct ucontext uc;
  57 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
  58         struct ucontext uc_transact;
  59 #endif
  60         unsigned long _unused[2];
  61         unsigned int tramp[TRAMP_SIZE];
  62         struct siginfo __user *pinfo;
  63         void __user *puc;
  64         struct siginfo info;
  65         /* New 64 bit little-endian ABI allows redzone of 512 bytes below sp */
  66         char abigap[USER_REDZONE_SIZE];
  67 } __attribute__ ((aligned (16)));
  68
  69 static const char fmt32[] = KERN_INFO \
  70         "%s[%d]: bad frame in %s: %08lx nip %08lx lr %08lx\n";
  71 static const char fmt64[] = KERN_INFO \
  72         "%s[%d]: bad frame in %s: %016lx nip %016lx lr %016lx\n";
  73
  74 /*
  75  * This computes a quad word aligned pointer inside the vmx_reserve array
  76  * element. For historical reasons sigcontext might not be quad word aligned,
  77  * but the location we write the VMX regs to must be. See the comment in
  78  * sigcontext for more detail.
  79  */
  80 #ifdef CONFIG_ALTIVEC
  81 static elf_vrreg_t __user *sigcontext_vmx_regs(struct sigcontext __user *sc)
  82 {
  83         return (elf_vrreg_t __user *) (((unsigned long)sc->vmx_reserve + 15) & ~0xful);
  84 }
  85 #endif
  86
  87 /*
  88  * Set up the sigcontext for the signal frame.
  89  */
  90
  91 static long setup_sigcontext(struct sigcontext __user *sc,
  92                 struct task_struct *tsk, int signr, sigset_t *set,
  93                 unsigned long handler, int ctx_has_vsx_region)
  94 {
  95         /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the
  96          * process never used altivec yet (MSR_VEC is zero in pt_regs of
  97          * the context). This is very important because we must ensure we
  98          * don't lose the VRSAVE content that may have been set prior to
  99          * the process doing its first vector operation
 100          * Userland shall check AT_HWCAP to know whether it can rely on the
 101          * v_regs pointer or not
 102          */
 103 #ifdef CONFIG_ALTIVEC
 104         elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc);
 105         unsigned long vrsave;
 106 #endif
 107         struct pt_regs *regs = tsk->thread.regs;
 108         unsigned long msr = regs->msr;
 109         long err = 0;
 110         /* Force usr to alway see softe as 1 (interrupts enabled) */
 111         unsigned long softe = 0x1;
 112
 113         BUG_ON(tsk != current);
 114
 115 #ifdef CONFIG_ALTIVEC
 116         err |= __put_user(v_regs, &sc->v_regs);
 117
 118         /* save altivec registers */
 119         if (tsk->thread.used_vr) {
 120                 flush_altivec_to_thread(tsk);
 121                 /* Copy 33 vec registers (vr0..31 and vscr) to the stack */
 122                 err |= __copy_to_user(v_regs, &tsk->thread.vr_state,
 123                                       33 * sizeof(vector128));
 124                 /* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg)
 125                  * contains valid data.
 126                  */
 127                 msr |= MSR_VEC;
 128         }
 129         /* We always copy to/from vrsave, it's 0 if we don't have or don't
 130          * use altivec.
 131          */
 132         vrsave = 0;
 133         if (cpu_has_feature(CPU_FTR_ALTIVEC)) {
 134                 vrsave = mfspr(SPRN_VRSAVE);
 135                 tsk->thread.vrsave = vrsave;
 136         }
 137
 138         err |= __put_user(vrsave, (u32 __user *)&v_regs[33]);
 139 #else /* CONFIG_ALTIVEC */
 140         err |= __put_user(0, &sc->v_regs);
 141 #endif /* CONFIG_ALTIVEC */
 142         flush_fp_to_thread(tsk);
 143         /* copy fpr regs and fpscr */
 144         err |= copy_fpr_to_user(&sc->fp_regs, tsk);
 145
 146         /*
 147          * Clear the MSR VSX bit to indicate there is no valid state attached
 148          * to this context, except in the specific case below where we set it.
 149          */
 150         msr &= ~MSR_VSX;
 151 #ifdef CONFIG_VSX
 152         /*
 153          * Copy VSX low doubleword to local buffer for formatting,
 154          * then out to userspace.  Update v_regs to point after the
 155          * VMX data.
 156          */
 157         if (tsk->thread.used_vsr && ctx_has_vsx_region) {
 158                 flush_vsx_to_thread(tsk);
 159                 v_regs += ELF_NVRREG;
 160                 err |= copy_vsx_to_user(v_regs, tsk);
 161                 /* set MSR_VSX in the MSR value in the frame to
 162                  * indicate that sc->vs_reg) contains valid data.
 163                  */
 164                 msr |= MSR_VSX;
 165         }
 166 #endif /* CONFIG_VSX */
 167         err |= __put_user(&sc->gp_regs, &sc->regs);
 168         WARN_ON(!FULL_REGS(regs));
 169         err |= __copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE);
 170         err |= __put_user(msr, &sc->gp_regs[PT_MSR]);
 171         err |= __put_user(softe, &sc->gp_regs[PT_SOFTE]);
 172         err |= __put_user(signr, &sc->signal);
 173         err |= __put_user(handler, &sc->handler);
 174         if (set != NULL)
 175                 err |=  __put_user(set->sig[0], &sc->oldmask);
 176
 177         return err;
 178 }
 179
 180 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 181 /*
 182  * As above, but Transactional Memory is in use, so deliver sigcontexts
 183  * containing checkpointed and transactional register states.
 184  *
 185  * To do this, we treclaim (done before entering here) to gather both sets of
 186  * registers and set up the 'normal' sigcontext registers with rolled-back
 187  * register values such that a simple signal handler sees a correct
 188  * checkpointed register state.  If interested, a TM-aware sighandler can
 189  * examine the transactional registers in the 2nd sigcontext to determine the
 190  * real origin of the signal.
 191  */
 192 static long setup_tm_sigcontexts(struct sigcontext __user *sc,
 193                                  struct sigcontext __user *tm_sc,
 194                                  struct task_struct *tsk,
 195                                  int signr, sigset_t *set, unsigned long handler,
 196                                  unsigned long msr)
 197 {
 198         /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the
 199          * process never used altivec yet (MSR_VEC is zero in pt_regs of
 200          * the context). This is very important because we must ensure we
 201          * don't lose the VRSAVE content that may have been set prior to
 202          * the process doing its first vector operation
 203          * Userland shall check AT_HWCAP to know wether it can rely on the
 204          * v_regs pointer or not.
 205          */
 206 #ifdef CONFIG_ALTIVEC
 207         elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc);
 208         elf_vrreg_t __user *tm_v_regs = sigcontext_vmx_regs(tm_sc);
 209 #endif
 210         struct pt_regs *regs = tsk->thread.regs;
 211         long err = 0;
 212
 213         BUG_ON(tsk != current);
 214
 215         BUG_ON(!MSR_TM_ACTIVE(msr));
 216
 217         WARN_ON(tm_suspend_disabled);
 218
 219         /* Restore checkpointed FP, VEC, and VSX bits from ckpt_regs as
 220          * it contains the correct FP, VEC, VSX state after we treclaimed
 221          * the transaction and giveup_all() was called on reclaiming.
 222          */
 223         msr |= tsk->thread.ckpt_regs.msr & (MSR_FP | MSR_VEC | MSR_VSX);
 224
 225 #ifdef CONFIG_ALTIVEC
 226         err |= __put_user(v_regs, &sc->v_regs);
 227         err |= __put_user(tm_v_regs, &tm_sc->v_regs);
 228
 229         /* save altivec registers */
 230         if (tsk->thread.used_vr) {
 231                 /* Copy 33 vec registers (vr0..31 and vscr) to the stack */
 232                 err |= __copy_to_user(v_regs, &tsk->thread.ckvr_state,
 233                                       33 * sizeof(vector128));
 234                 /* If VEC was enabled there are transactional VRs valid too,
 235                  * else they're a copy of the checkpointed VRs.
 236                  */
 237                 if (msr & MSR_VEC)
 238                         err |= __copy_to_user(tm_v_regs,
 239                                               &tsk->thread.vr_state,
 240                                               33 * sizeof(vector128));
 241                 else
 242                         err |= __copy_to_user(tm_v_regs,
 243                                               &tsk->thread.ckvr_state,
 244                                               33 * sizeof(vector128));
 245
 246                 /* set MSR_VEC in the MSR value in the frame to indicate
 247                  * that sc->v_reg contains valid data.
 248                  */
 249                 msr |= MSR_VEC;
 250         }
 251         /* We always copy to/from vrsave, it's 0 if we don't have or don't
 252          * use altivec.
 253          */
 254         if (cpu_has_feature(CPU_FTR_ALTIVEC))
 255                 tsk->thread.ckvrsave = mfspr(SPRN_VRSAVE);
 256         err |= __put_user(tsk->thread.ckvrsave, (u32 __user *)&v_regs[33]);
 257         if (msr & MSR_VEC)
 258                 err |= __put_user(tsk->thread.vrsave,
 259                                   (u32 __user *)&tm_v_regs[33]);
 260         else
 261                 err |= __put_user(tsk->thread.ckvrsave,
 262                                   (u32 __user *)&tm_v_regs[33]);
 263
 264 #else /* CONFIG_ALTIVEC */
 265         err |= __put_user(0, &sc->v_regs);
 266         err |= __put_user(0, &tm_sc->v_regs);
 267 #endif /* CONFIG_ALTIVEC */
 268
 269         /* copy fpr regs and fpscr */
 270         err |= copy_ckfpr_to_user(&sc->fp_regs, tsk);
 271         if (msr & MSR_FP)
 272                 err |= copy_fpr_to_user(&tm_sc->fp_regs, tsk);
 273         else
 274                 err |= copy_ckfpr_to_user(&tm_sc->fp_regs, tsk);
 275
 276 #ifdef CONFIG_VSX
 277         /*
 278          * Copy VSX low doubleword to local buffer for formatting,
 279          * then out to userspace.  Update v_regs to point after the
 280          * VMX data.
 281          */
 282         if (tsk->thread.used_vsr) {
 283                 v_regs += ELF_NVRREG;
 284                 tm_v_regs += ELF_NVRREG;
 285
 286                 err |= copy_ckvsx_to_user(v_regs, tsk);
 287
 288                 if (msr & MSR_VSX)
 289                         err |= copy_vsx_to_user(tm_v_regs, tsk);
 290                 else
 291                         err |= copy_ckvsx_to_user(tm_v_regs, tsk);
 292
 293                 /* set MSR_VSX in the MSR value in the frame to
 294                  * indicate that sc->vs_reg) contains valid data.
 295                  */
 296                 msr |= MSR_VSX;
 297         }
 298 #endif /* CONFIG_VSX */
 299
 300         err |= __put_user(&sc->gp_regs, &sc->regs);
 301         err |= __put_user(&tm_sc->gp_regs, &tm_sc->regs);
 302         WARN_ON(!FULL_REGS(regs));
 303         err |= __copy_to_user(&tm_sc->gp_regs, regs, GP_REGS_SIZE);
 304         err |= __copy_to_user(&sc->gp_regs,
 305                               &tsk->thread.ckpt_regs, GP_REGS_SIZE);
 306         err |= __put_user(msr, &tm_sc->gp_regs[PT_MSR]);
 307         err |= __put_user(msr, &sc->gp_regs[PT_MSR]);
 308         err |= __put_user(signr, &sc->signal);
 309         err |= __put_user(handler, &sc->handler);
 310         if (set != NULL)
 311                 err |=  __put_user(set->sig[0], &sc->oldmask);
 312
 313         return err;
 314 }
 315 #endif
 316
 317 /*
 318  * Restore the sigcontext from the signal frame.
 319  */
 320
 321 static long restore_sigcontext(struct task_struct *tsk, sigset_t *set, int sig,
 322                               struct sigcontext __user *sc)
 323 {
 324 #ifdef CONFIG_ALTIVEC
 325         elf_vrreg_t __user *v_regs;
 326 #endif
 327         unsigned long err = 0;
 328         unsigned long save_r13 = 0;
 329         unsigned long msr;
 330         struct pt_regs *regs = tsk->thread.regs;
 331 #ifdef CONFIG_VSX
 332         int i;
 333 #endif
 334
 335         BUG_ON(tsk != current);
 336
 337         /* If this is not a signal return, we preserve the TLS in r13 */
 338         if (!sig)
 339                 save_r13 = regs->gpr[13];
 340
 341         /* copy the GPRs */
 342         err |= __copy_from_user(regs->gpr, sc->gp_regs, sizeof(regs->gpr));
 343         err |= __get_user(regs->nip, &sc->gp_regs[PT_NIP]);
 344         /* get MSR separately, transfer the LE bit if doing signal return */
 345         err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
 346         if (sig)
 347                 regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);
 348         err |= __get_user(regs->orig_gpr3, &sc->gp_regs[PT_ORIG_R3]);
 349         err |= __get_user(regs->ctr, &sc->gp_regs[PT_CTR]);
 350         err |= __get_user(regs->link, &sc->gp_regs[PT_LNK]);
 351         err |= __get_user(regs->xer, &sc->gp_regs[PT_XER]);
 352         err |= __get_user(regs->ccr, &sc->gp_regs[PT_CCR]);
 353         /* skip SOFTE */
 354         regs->trap = 0;
 355         err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]);
 356         err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]);
 357         err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]);
 358
 359         if (!sig)
 360                 regs->gpr[13] = save_r13;
 361         if (set != NULL)
 362                 err |=  __get_user(set->sig[0], &sc->oldmask);
 363
 364         /*
 365          * Force reload of FP/VEC.
 366          * This has to be done before copying stuff into tsk->thread.fpr/vr
 367          * for the reasons explained in the previous comment.
 368          */
 369         regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX);
 370
 371 #ifdef CONFIG_ALTIVEC
 372         err |= __get_user(v_regs, &sc->v_regs);
 373         if (err)
 374                 return err;
 375         if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128)))
 376                 return -EFAULT;
 377         /* Copy 33 vec registers (vr0..31 and vscr) from the stack */
 378         if (v_regs != NULL && (msr & MSR_VEC) != 0) {
 379                 err |= __copy_from_user(&tsk->thread.vr_state, v_regs,
 380                                         33 * sizeof(vector128));
 381                 tsk->thread.used_vr = true;
 382         } else if (tsk->thread.used_vr) {
 383                 memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128));
 384         }
 385         /* Always get VRSAVE back */
 386         if (v_regs != NULL)
 387                 err |= __get_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33]);
 388         else
 389                 tsk->thread.vrsave = 0;
 390         if (cpu_has_feature(CPU_FTR_ALTIVEC))
 391                 mtspr(SPRN_VRSAVE, tsk->thread.vrsave);
 392 #endif /* CONFIG_ALTIVEC */
 393         /* restore floating point */
 394         err |= copy_fpr_from_user(tsk, &sc->fp_regs);
 395 #ifdef CONFIG_VSX
 396         /*
 397          * Get additional VSX data. Update v_regs to point after the
 398          * VMX data.  Copy VSX low doubleword from userspace to local
 399          * buffer for formatting, then into the taskstruct.
 400          */
 401         v_regs += ELF_NVRREG;
 402         if ((msr & MSR_VSX) != 0) {
 403                 err |= copy_vsx_from_user(tsk, v_regs);
 404                 tsk->thread.used_vsr = true;
 405         } else {
 406                 for (i = 0; i < 32 ; i++)
 407                         tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
 408         }
 409 #endif
 410         return err;
 411 }
 412
 413 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 414 /*
 415  * Restore the two sigcontexts from the frame of a transactional processes.
 416  */
 417
 418 static long restore_tm_sigcontexts(struct task_struct *tsk,
 419                                    struct sigcontext __user *sc,
 420                                    struct sigcontext __user *tm_sc)
 421 {
 422 #ifdef CONFIG_ALTIVEC
 423         elf_vrreg_t __user *v_regs, *tm_v_regs;
 424 #endif
 425         unsigned long err = 0;
 426         unsigned long msr;
 427         struct pt_regs *regs = tsk->thread.regs;
 428 #ifdef CONFIG_VSX
 429         int i;
 430 #endif
 431
 432         BUG_ON(tsk != current);
 433
 434         if (tm_suspend_disabled)
 435                 return -EINVAL;
 436
 437         /* copy the GPRs */
 438         err |= __copy_from_user(regs->gpr, tm_sc->gp_regs, sizeof(regs->gpr));
 439         err |= __copy_from_user(&tsk->thread.ckpt_regs, sc->gp_regs,
 440                                 sizeof(regs->gpr));
 441
 442         /*
 443          * TFHAR is restored from the checkpointed 'wound-back' ucontext's NIP.
 444          * TEXASR was set by the signal delivery reclaim, as was TFIAR.
 445          * Users doing anything abhorrent like thread-switching w/ signals for
 446          * TM-Suspended code will have to back TEXASR/TFIAR up themselves.
 447          * For the case of getting a signal and simply returning from it,
 448          * we don't need to re-copy them here.
 449          */
 450         err |= __get_user(regs->nip, &tm_sc->gp_regs[PT_NIP]);
 451         err |= __get_user(tsk->thread.tm_tfhar, &sc->gp_regs[PT_NIP]);
 452
 453         /* get MSR separately, transfer the LE bit if doing signal return */
 454         err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
 455         /* Don't allow reserved mode. */
 456         if (MSR_TM_RESV(msr))
 457                 return -EINVAL;
 458
 459         /* pull in MSR LE from user context */
 460         regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);
 461
 462         /* The following non-GPR non-FPR non-VR state is also checkpointed: */
 463         err |= __get_user(regs->ctr, &tm_sc->gp_regs[PT_CTR]);
 464         err |= __get_user(regs->link, &tm_sc->gp_regs[PT_LNK]);
 465         err |= __get_user(regs->xer, &tm_sc->gp_regs[PT_XER]);
 466         err |= __get_user(regs->ccr, &tm_sc->gp_regs[PT_CCR]);
 467         err |= __get_user(tsk->thread.ckpt_regs.ctr,
 468                           &sc->gp_regs[PT_CTR]);
 469         err |= __get_user(tsk->thread.ckpt_regs.link,
 470                           &sc->gp_regs[PT_LNK]);
 471         err |= __get_user(tsk->thread.ckpt_regs.xer,
 472                           &sc->gp_regs[PT_XER]);
 473         err |= __get_user(tsk->thread.ckpt_regs.ccr,
 474                           &sc->gp_regs[PT_CCR]);
 475
 476         /* These regs are not checkpointed; they can go in 'regs'. */
 477         err |= __get_user(regs->trap, &sc->gp_regs[PT_TRAP]);
 478         err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]);
 479         err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]);
 480         err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]);
 481
 482         /*
 483          * Force reload of FP/VEC.
 484          * This has to be done before copying stuff into tsk->thread.fpr/vr
 485          * for the reasons explained in the previous comment.
 486          */
 487         regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX);
 488
 489 #ifdef CONFIG_ALTIVEC
 490         err |= __get_user(v_regs, &sc->v_regs);
 491         err |= __get_user(tm_v_regs, &tm_sc->v_regs);
 492         if (err)
 493                 return err;
 494         if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128)))
 495                 return -EFAULT;
 496         if (tm_v_regs && !access_ok(tm_v_regs, 34 * sizeof(vector128)))
 497                 return -EFAULT;
 498         /* Copy 33 vec registers (vr0..31 and vscr) from the stack */
 499         if (v_regs != NULL && tm_v_regs != NULL && (msr & MSR_VEC) != 0) {
 500                 err |= __copy_from_user(&tsk->thread.ckvr_state, v_regs,
 501                                         33 * sizeof(vector128));
 502                 err |= __copy_from_user(&tsk->thread.vr_state, tm_v_regs,
 503                                         33 * sizeof(vector128));
 504                 current->thread.used_vr = true;
 505         }
 506         else if (tsk->thread.used_vr) {
 507                 memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128));
 508                 memset(&tsk->thread.ckvr_state, 0, 33 * sizeof(vector128));
 509         }
 510         /* Always get VRSAVE back */
 511         if (v_regs != NULL && tm_v_regs != NULL) {
 512                 err |= __get_user(tsk->thread.ckvrsave,
 513                                   (u32 __user *)&v_regs[33]);
 514                 err |= __get_user(tsk->thread.vrsave,
 515                                   (u32 __user *)&tm_v_regs[33]);
 516         }
 517         else {
 518                 tsk->thread.vrsave = 0;
 519                 tsk->thread.ckvrsave = 0;
 520         }
 521         if (cpu_has_feature(CPU_FTR_ALTIVEC))
 522                 mtspr(SPRN_VRSAVE, tsk->thread.vrsave);
 523 #endif /* CONFIG_ALTIVEC */
 524         /* restore floating point */
 525         err |= copy_fpr_from_user(tsk, &tm_sc->fp_regs);
 526         err |= copy_ckfpr_from_user(tsk, &sc->fp_regs);
 527 #ifdef CONFIG_VSX
 528         /*
 529          * Get additional VSX data. Update v_regs to point after the
 530          * VMX data.  Copy VSX low doubleword from userspace to local
 531          * buffer for formatting, then into the taskstruct.
 532          */
 533         if (v_regs && ((msr & MSR_VSX) != 0)) {
 534                 v_regs += ELF_NVRREG;
 535                 tm_v_regs += ELF_NVRREG;
 536                 err |= copy_vsx_from_user(tsk, tm_v_regs);
 537                 err |= copy_ckvsx_from_user(tsk, v_regs);
 538                 tsk->thread.used_vsr = true;
 539         } else {
 540                 for (i = 0; i < 32 ; i++) {
 541                         tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
 542                         tsk->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
 543                 }
 544         }
 545 #endif
 546         tm_enable();
 547         /* Make sure the transaction is marked as failed */
 548         tsk->thread.tm_texasr |= TEXASR_FS;
 549
 550         /*
 551          * Disabling preemption, since it is unsafe to be preempted
 552          * with MSR[TS] set without recheckpointing.
 553          */
 554         preempt_disable();
 555
 556         /* pull in MSR TS bits from user context */
 557         regs->msr |= msr & MSR_TS_MASK;
 558
 559         /*
 560          * Ensure that TM is enabled in regs->msr before we leave the signal
 561          * handler. It could be the case that (a) user disabled the TM bit
 562          * through the manipulation of the MSR bits in uc_mcontext or (b) the
 563          * TM bit was disabled because a sufficient number of context switches
 564          * happened whilst in the signal handler and load_tm overflowed,
 565          * disabling the TM bit. In either case we can end up with an illegal
 566          * TM state leading to a TM Bad Thing when we return to userspace.
 567          *
 568          * CAUTION:
 569          * After regs->MSR[TS] being updated, make sure that get_user(),
 570          * put_user() or similar functions are *not* called. These
 571          * functions can generate page faults which will cause the process
 572          * to be de-scheduled with MSR[TS] set but without calling
 573          * tm_recheckpoint(). This can cause a bug.
 574          */
 575         regs->msr |= MSR_TM;
 576
 577         /* This loads the checkpointed FP/VEC state, if used */
 578         tm_recheckpoint(&tsk->thread);
 579
 580         msr_check_and_set(msr & (MSR_FP | MSR_VEC));
 581         if (msr & MSR_FP) {
 582                 load_fp_state(&tsk->thread.fp_state);
 583                 regs->msr |= (MSR_FP | tsk->thread.fpexc_mode);
 584         }
 585         if (msr & MSR_VEC) {
 586                 load_vr_state(&tsk->thread.vr_state);
 587                 regs->msr |= MSR_VEC;
 588         }
 589
 590         preempt_enable();
 591
 592         return err;
 593 }
 594 #endif
 595
 596 /*
 597  * Setup the trampoline code on the stack
 598  */
 599 static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp)
 600 {
 601         int i;
 602         long err = 0;
 603
 604         /* addi r1, r1, __SIGNAL_FRAMESIZE  # Pop the dummy stackframe */
 605         err |= __put_user(PPC_INST_ADDI | __PPC_RT(R1) | __PPC_RA(R1) |
 606                           (__SIGNAL_FRAMESIZE & 0xffff), &tramp[0]);
 607         /* li r0, __NR_[rt_]sigreturn| */
 608         err |= __put_user(PPC_INST_ADDI | (syscall & 0xffff), &tramp[1]);
 609         /* sc */
 610         err |= __put_user(PPC_INST_SC, &tramp[2]);
 611
 612         /* Minimal traceback info */
 613         for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++)
 614                 err |= __put_user(0, &tramp[i]);
 615
 616         if (!err)
 617                 flush_icache_range((unsigned long) &tramp[0],
 618                            (unsigned long) &tramp[TRAMP_SIZE]);
 619
 620         return err;
 621 }
 622
 623 /*
 624  * Userspace code may pass a ucontext which doesn't include VSX added
 625  * at the end.  We need to check for this case.
 626  */
 627 #define UCONTEXTSIZEWITHOUTVSX \
 628                 (sizeof(struct ucontext) - 32*sizeof(long))
 629
 630 /*
 631  * Handle {get,set,swap}_context operations
 632  */
 633 SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx,
 634                 struct ucontext __user *, new_ctx, long, ctx_size)
 635 {
 636         unsigned char tmp;
 637         sigset_t set;
 638         unsigned long new_msr = 0;
 639         int ctx_has_vsx_region = 0;
 640
 641         if (new_ctx &&
 642             get_user(new_msr, &new_ctx->uc_mcontext.gp_regs[PT_MSR]))
 643                 return -EFAULT;
 644         /*
 645          * Check that the context is not smaller than the original
 646          * size (with VMX but without VSX)
 647          */
 648         if (ctx_size < UCONTEXTSIZEWITHOUTVSX)
 649                 return -EINVAL;
 650         /*
 651          * If the new context state sets the MSR VSX bits but
 652          * it doesn't provide VSX state.
 653          */
 654         if ((ctx_size < sizeof(struct ucontext)) &&
 655             (new_msr & MSR_VSX))
 656                 return -EINVAL;
 657         /* Does the context have enough room to store VSX data? */
 658         if (ctx_size >= sizeof(struct ucontext))
 659                 ctx_has_vsx_region = 1;
 660
 661         if (old_ctx != NULL) {
 662                 if (!access_ok(old_ctx, ctx_size)
 663                     || setup_sigcontext(&old_ctx->uc_mcontext, current, 0, NULL, 0,
 664                                         ctx_has_vsx_region)
 665                     || __copy_to_user(&old_ctx->uc_sigmask,
 666                                       &current->blocked, sizeof(sigset_t)))
 667                         return -EFAULT;
 668         }
 669         if (new_ctx == NULL)
 670                 return 0;
 671         if (!access_ok(new_ctx, ctx_size)
 672             || __get_user(tmp, (u8 __user *) new_ctx)
 673             || __get_user(tmp, (u8 __user *) new_ctx + ctx_size - 1))
 674                 return -EFAULT;
 675
 676         /*
 677          * If we get a fault copying the context into the kernel's
 678          * image of the user's registers, we can't just return -EFAULT
 679          * because the user's registers will be corrupted.  For instance
 680          * the NIP value may have been updated but not some of the
 681          * other registers.  Given that we have done the access_ok
 682          * and successfully read the first and last bytes of the region
 683          * above, this should only happen in an out-of-memory situation
 684          * or if another thread unmaps the region containing the context.
 685          * We kill the task with a SIGSEGV in this situation.
 686          */
 687
 688         if (__copy_from_user(&set, &new_ctx->uc_sigmask, sizeof(set)))
 689                 do_exit(SIGSEGV);
 690         set_current_blocked(&set);
 691         if (restore_sigcontext(current, NULL, 0, &new_ctx->uc_mcontext))
 692                 do_exit(SIGSEGV);
 693
 694         /* This returns like rt_sigreturn */
 695         set_thread_flag(TIF_RESTOREALL);
 696         return 0;
 697 }
 698
 699
 700 /*
 701  * Do a signal return; undo the signal stack.
 702  */
 703
 704 SYSCALL_DEFINE0(rt_sigreturn)
 705 {
 706         struct pt_regs *regs = current_pt_regs();
 707         struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1];
 708         sigset_t set;
 709 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 710         unsigned long msr;
 711 #endif
 712
 713         /* Always make any pending restarted system calls return -EINTR */
 714         current->restart_block.fn = do_no_restart_syscall;
 715
 716         if (!access_ok(uc, sizeof(*uc)))
 717                 goto badframe;
 718
 719         if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
 720                 goto badframe;
 721         set_current_blocked(&set);
 722
 723 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 724         /*
 725          * If there is a transactional state then throw it away.
 726          * The purpose of a sigreturn is to destroy all traces of the
 727          * signal frame, this includes any transactional state created
 728          * within in. We only check for suspended as we can never be
 729          * active in the kernel, we are active, there is nothing better to
 730          * do than go ahead and Bad Thing later.
 731          * The cause is not important as there will never be a
 732          * recheckpoint so it's not user visible.
 733          */
 734         if (MSR_TM_SUSPENDED(mfmsr()))
 735                 tm_reclaim_current(0);
 736
 737         /*
 738          * Disable MSR[TS] bit also, so, if there is an exception in the
 739          * code below (as a page fault in copy_ckvsx_to_user()), it does
 740          * not recheckpoint this task if there was a context switch inside
 741          * the exception.
 742          *
 743          * A major page fault can indirectly call schedule(). A reschedule
 744          * process in the middle of an exception can have a side effect
 745          * (Changing the CPU MSR[TS] state), since schedule() is called
 746          * with the CPU MSR[TS] disable and returns with MSR[TS]=Suspended
 747          * (switch_to() calls tm_recheckpoint() for the 'new' process). In
 748          * this case, the process continues to be the same in the CPU, but
 749          * the CPU state just changed.
 750          *
 751          * This can cause a TM Bad Thing, since the MSR in the stack will
 752          * have the MSR[TS]=0, and this is what will be used to RFID.
 753          *
 754          * Clearing MSR[TS] state here will avoid a recheckpoint if there
 755          * is any process reschedule in kernel space. The MSR[TS] state
 756          * does not need to be saved also, since it will be replaced with
 757          * the MSR[TS] that came from user context later, at
 758          * restore_tm_sigcontexts.
 759          */
 760         regs->msr &= ~MSR_TS_MASK;
 761
 762         if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR]))
 763                 goto badframe;
 764         if (MSR_TM_ACTIVE(msr)) {
 765                 /* We recheckpoint on return. */
 766                 struct ucontext __user *uc_transact;
 767
 768                 /* Trying to start TM on non TM system */
 769                 if (!cpu_has_feature(CPU_FTR_TM))
 770                         goto badframe;
 771
 772                 if (__get_user(uc_transact, &uc->uc_link))
 773                         goto badframe;
 774                 if (restore_tm_sigcontexts(current, &uc->uc_mcontext,
 775                                            &uc_transact->uc_mcontext))
 776                         goto badframe;
 777         } else
 778 #endif
 779         {
 780                 /*
 781                  * Fall through, for non-TM restore
 782                  *
 783                  * Unset MSR[TS] on the thread regs since MSR from user
 784                  * context does not have MSR active, and recheckpoint was
 785                  * not called since restore_tm_sigcontexts() was not called
 786                  * also.
 787                  *
 788                  * If not unsetting it, the code can RFID to userspace with
 789                  * MSR[TS] set, but without CPU in the proper state,
 790                  * causing a TM bad thing.
 791                  */
 792                 current->thread.regs->msr &= ~MSR_TS_MASK;
 793                 if (restore_sigcontext(current, NULL, 1, &uc->uc_mcontext))
 794                         goto badframe;
 795         }
 796
 797         if (restore_altstack(&uc->uc_stack))
 798                 goto badframe;
 799
 800         set_thread_flag(TIF_RESTOREALL);
 801         return 0;
 802
 803 badframe:
 804         if (show_unhandled_signals)
 805                 printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32,
 806                                    current->comm, current->pid, "rt_sigreturn",
 807                                    (long)uc, regs->nip, regs->link);
 808
 809         force_sig(SIGSEGV);
 810         return 0;
 811 }
 812
 813 int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
 814                 struct task_struct *tsk)
 815 {
 816         struct rt_sigframe __user *frame;
 817         unsigned long newsp = 0;
 818         long err = 0;
 819         struct pt_regs *regs = tsk->thread.regs;
 820 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 821         /* Save the thread's msr before get_tm_stackpointer() changes it */
 822         unsigned long msr = regs->msr;
 823 #endif
 824
 825         BUG_ON(tsk != current);
 826
 827         frame = get_sigframe(ksig, get_tm_stackpointer(tsk), sizeof(*frame), 0);
 828         if (unlikely(frame == NULL))
 829                 goto badframe;
 830
 831         err |= __put_user(&frame->info, &frame->pinfo);
 832         err |= __put_user(&frame->uc, &frame->puc);
 833         err |= copy_siginfo_to_user(&frame->info, &ksig->info);
 834         if (err)
 835                 goto badframe;
 836
 837         /* Create the ucontext.  */
 838         err |= __put_user(0, &frame->uc.uc_flags);
 839         err |= __save_altstack(&frame->uc.uc_stack, regs->gpr[1]);
 840 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 841         if (MSR_TM_ACTIVE(msr)) {
 842                 /* The ucontext_t passed to userland points to the second
 843                  * ucontext_t (for transactional state) with its uc_link ptr.
 844                  */
 845                 err |= __put_user(&frame->uc_transact, &frame->uc.uc_link);
 846                 err |= setup_tm_sigcontexts(&frame->uc.uc_mcontext,
 847                                             &frame->uc_transact.uc_mcontext,
 848                                             tsk, ksig->sig, NULL,
 849                                             (unsigned long)ksig->ka.sa.sa_handler,
 850                                             msr);
 851         } else
 852 #endif
 853         {
 854                 err |= __put_user(0, &frame->uc.uc_link);
 855                 err |= setup_sigcontext(&frame->uc.uc_mcontext, tsk, ksig->sig,
 856                                         NULL, (unsigned long)ksig->ka.sa.sa_handler,
 857                                         1);
 858         }
 859         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 860         if (err)
 861                 goto badframe;
 862
 863         /* Make sure signal handler doesn't get spurious FP exceptions */
 864         tsk->thread.fp_state.fpscr = 0;
 865
 866         /* Set up to return from userspace. */
 867         if (vdso64_rt_sigtramp && tsk->mm->context.vdso_base) {
 868                 regs->link = tsk->mm->context.vdso_base + vdso64_rt_sigtramp;
 869         } else {
 870                 err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]);
 871                 if (err)
 872                         goto badframe;
 873                 regs->link = (unsigned long) &frame->tramp[0];
 874         }
 875
 876         /* Allocate a dummy caller frame for the signal handler. */
 877         newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE;
 878         err |= put_user(regs->gpr[1], (unsigned long __user *)newsp);
 879
 880         /* Set up "regs" so we "return" to the signal handler. */
 881         if (is_elf2_task()) {
 882                 regs->nip = (unsigned long) ksig->ka.sa.sa_handler;
 883                 regs->gpr[12] = regs->nip;
 884         } else {
 885                 /* Handler is *really* a pointer to the function descriptor for
 886                  * the signal routine.  The first entry in the function
 887                  * descriptor is the entry address of signal and the second
 888                  * entry is the TOC value we need to use.
 889                  */
 890                 func_descr_t __user *funct_desc_ptr =
 891                         (func_descr_t __user *) ksig->ka.sa.sa_handler;
 892
 893                 err |= get_user(regs->nip, &funct_desc_ptr->entry);
 894                 err |= get_user(regs->gpr[2], &funct_desc_ptr->toc);
 895         }
 896
 897         /* enter the signal handler in native-endian mode */
 898         regs->msr &= ~MSR_LE;
 899         regs->msr |= (MSR_KERNEL & MSR_LE);
 900         regs->gpr[1] = newsp;
 901         regs->gpr[3] = ksig->sig;
 902         regs->result = 0;
 903         if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
 904                 err |= get_user(regs->gpr[4], (unsigned long __user *)&frame->pinfo);
 905                 err |= get_user(regs->gpr[5], (unsigned long __user *)&frame->puc);
 906                 regs->gpr[6] = (unsigned long) frame;
 907         } else {
 908                 regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext;
 909         }
 910         if (err)
 911                 goto badframe;
 912
 913         return 0;
 914
 915 badframe:
 916         if (show_unhandled_signals)
 917                 printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32,
 918                                    tsk->comm, tsk->pid, "setup_rt_frame",
 919                                    (long)frame, regs->nip, regs->link);
 920
 921         return 1;
 922 }