arch/powerpc/kernel/signal_64.c

   1 /*
   2  *  PowerPC version
   3  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
   4  *
   5  *  Derived from "arch/i386/kernel/signal.c"
   6  *    Copyright (C) 1991, 1992 Linus Torvalds
   7  *    1997-11-28  Modified for POSIX.1b signals by Richard Henderson
   8  *
   9  *  This program is free software; you can redistribute it and/or
  10  *  modify it under the terms of the GNU General Public License
  11  *  as published by the Free Software Foundation; either version
  12  *  2 of the License, or (at your option) any later version.
  13  */
  14
  15 #include <linux/sched.h>
  16 #include <linux/mm.h>
  17 #include <linux/smp.h>
  18 #include <linux/kernel.h>
  19 #include <linux/signal.h>
  20 #include <linux/errno.h>
  21 #include <linux/wait.h>
  22 #include <linux/unistd.h>
  23 #include <linux/stddef.h>
  24 #include <linux/elf.h>
  25 #include <linux/ptrace.h>
  26 #include <linux/ratelimit.h>
  27
  28 #include <asm/sigcontext.h>
  29 #include <asm/ucontext.h>
  30 #include <asm/uaccess.h>
  31 #include <asm/pgtable.h>
  32 #include <asm/unistd.h>
  33 #include <asm/cacheflush.h>
  34 #include <asm/syscalls.h>
  35 #include <asm/vdso.h>
  36 #include <asm/switch_to.h>
  37 #include <asm/tm.h>
  38
  39 #include "signal.h"
  40
  41
  42 #define GP_REGS_SIZE    min(sizeof(elf_gregset_t), sizeof(struct pt_regs))
  43 #define FP_REGS_SIZE    sizeof(elf_fpregset_t)
  44
  45 #define TRAMP_TRACEBACK 3
  46 #define TRAMP_SIZE      6
  47
  48 /*
  49  * When we have signals to deliver, we set up on the user stack,
  50  * going down from the original stack pointer:
  51  *      1) a rt_sigframe struct which contains the ucontext
  52  *      2) a gap of __SIGNAL_FRAMESIZE bytes which acts as a dummy caller
  53  *         frame for the signal handler.
  54  */
  55
  56 struct rt_sigframe {
  57         /* sys_rt_sigreturn requires the ucontext be the first field */
  58         struct ucontext uc;
  59 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
  60         struct ucontext uc_transact;
  61 #endif
  62         unsigned long _unused[2];
  63         unsigned int tramp[TRAMP_SIZE];
  64         struct siginfo __user *pinfo;
  65         void __user *puc;
  66         struct siginfo info;
  67         /* New 64 bit little-endian ABI allows redzone of 512 bytes below sp */
  68         char abigap[USER_REDZONE_SIZE];
  69 } __attribute__ ((aligned (16)));
  70
  71 static const char fmt32[] = KERN_INFO \
  72         "%s[%d]: bad frame in %s: %08lx nip %08lx lr %08lx\n";
  73 static const char fmt64[] = KERN_INFO \
  74         "%s[%d]: bad frame in %s: %016lx nip %016lx lr %016lx\n";
  75
  76 /*
  77  * This computes a quad word aligned pointer inside the vmx_reserve array
  78  * element. For historical reasons sigcontext might not be quad word aligned,
  79  * but the location we write the VMX regs to must be. See the comment in
  80  * sigcontext for more detail.
  81  */
  82 #ifdef CONFIG_ALTIVEC
  83 static elf_vrreg_t __user *sigcontext_vmx_regs(struct sigcontext __user *sc)
  84 {
  85         return (elf_vrreg_t __user *) (((unsigned long)sc->vmx_reserve + 15) & ~0xful);
  86 }
  87 #endif
  88
  89 /*
  90  * Set up the sigcontext for the signal frame.
  91  */
  92
  93 static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
  94                  int signr, sigset_t *set, unsigned long handler,
  95                  int ctx_has_vsx_region)
  96 {
  97         /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the
  98          * process never used altivec yet (MSR_VEC is zero in pt_regs of
  99          * the context). This is very important because we must ensure we
 100          * don't lose the VRSAVE content that may have been set prior to
 101          * the process doing its first vector operation
 102          * Userland shall check AT_HWCAP to know whether it can rely on the
 103          * v_regs pointer or not
 104          */
 105 #ifdef CONFIG_ALTIVEC
 106         elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc);
 107 #endif
 108         unsigned long msr = regs->msr;
 109         long err = 0;
 110
 111 #ifdef CONFIG_ALTIVEC
 112         err |= __put_user(v_regs, &sc->v_regs);
 113
 114         /* save altivec registers */
 115         if (current->thread.used_vr) {
 116                 flush_altivec_to_thread(current);
 117                 /* Copy 33 vec registers (vr0..31 and vscr) to the stack */
 118                 err |= __copy_to_user(v_regs, &current->thread.vr_state,
 119                                       33 * sizeof(vector128));
 120                 /* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg)
 121                  * contains valid data.
 122                  */
 123                 msr |= MSR_VEC;
 124         }
 125         /* We always copy to/from vrsave, it's 0 if we don't have or don't
 126          * use altivec.
 127          */
 128         if (cpu_has_feature(CPU_FTR_ALTIVEC))
 129                 current->thread.vrsave = mfspr(SPRN_VRSAVE);
 130         err |= __put_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
 131 #else /* CONFIG_ALTIVEC */
 132         err |= __put_user(0, &sc->v_regs);
 133 #endif /* CONFIG_ALTIVEC */
 134         flush_fp_to_thread(current);
 135         /* copy fpr regs and fpscr */
 136         err |= copy_fpr_to_user(&sc->fp_regs, current);
 137
 138         /*
 139          * Clear the MSR VSX bit to indicate there is no valid state attached
 140          * to this context, except in the specific case below where we set it.
 141          */
 142         msr &= ~MSR_VSX;
 143 #ifdef CONFIG_VSX
 144         /*
 145          * Copy VSX low doubleword to local buffer for formatting,
 146          * then out to userspace.  Update v_regs to point after the
 147          * VMX data.
 148          */
 149         if (current->thread.used_vsr && ctx_has_vsx_region) {
 150                 __giveup_vsx(current);
 151                 v_regs += ELF_NVRREG;
 152                 err |= copy_vsx_to_user(v_regs, current);
 153                 /* set MSR_VSX in the MSR value in the frame to
 154                  * indicate that sc->vs_reg) contains valid data.
 155                  */
 156                 msr |= MSR_VSX;
 157         }
 158 #endif /* CONFIG_VSX */
 159         err |= __put_user(&sc->gp_regs, &sc->regs);
 160         WARN_ON(!FULL_REGS(regs));
 161         err |= __copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE);
 162         err |= __put_user(msr, &sc->gp_regs[PT_MSR]);
 163         err |= __put_user(signr, &sc->signal);
 164         err |= __put_user(handler, &sc->handler);
 165         if (set != NULL)
 166                 err |=  __put_user(set->sig[0], &sc->oldmask);
 167
 168         return err;
 169 }
 170
 171 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 172 /*
 173  * As above, but Transactional Memory is in use, so deliver sigcontexts
 174  * containing checkpointed and transactional register states.
 175  *
 176  * To do this, we treclaim (done before entering here) to gather both sets of
 177  * registers and set up the 'normal' sigcontext registers with rolled-back
 178  * register values such that a simple signal handler sees a correct
 179  * checkpointed register state.  If interested, a TM-aware sighandler can
 180  * examine the transactional registers in the 2nd sigcontext to determine the
 181  * real origin of the signal.
 182  */
 183 static long setup_tm_sigcontexts(struct sigcontext __user *sc,
 184                                  struct sigcontext __user *tm_sc,
 185                                  struct pt_regs *regs,
 186                                  int signr, sigset_t *set, unsigned long handler)
 187 {
 188         /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the
 189          * process never used altivec yet (MSR_VEC is zero in pt_regs of
 190          * the context). This is very important because we must ensure we
 191          * don't lose the VRSAVE content that may have been set prior to
 192          * the process doing its first vector operation
 193          * Userland shall check AT_HWCAP to know wether it can rely on the
 194          * v_regs pointer or not.
 195          */
 196 #ifdef CONFIG_ALTIVEC
 197         elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc);
 198         elf_vrreg_t __user *tm_v_regs = sigcontext_vmx_regs(tm_sc);
 199 #endif
 200         unsigned long msr = regs->msr;
 201         long err = 0;
 202
 203         BUG_ON(!MSR_TM_ACTIVE(regs->msr));
 204
 205         /* Remove TM bits from thread's MSR.  The MSR in the sigcontext
 206          * just indicates to userland that we were doing a transaction, but we
 207          * don't want to return in transactional state.  This also ensures
 208          * that flush_fp_to_thread won't set TIF_RESTORE_TM again.
 209          */
 210         regs->msr &= ~MSR_TS_MASK;
 211
 212         flush_fp_to_thread(current);
 213
 214 #ifdef CONFIG_ALTIVEC
 215         err |= __put_user(v_regs, &sc->v_regs);
 216         err |= __put_user(tm_v_regs, &tm_sc->v_regs);
 217
 218         /* save altivec registers */
 219         if (current->thread.used_vr) {
 220                 flush_altivec_to_thread(current);
 221                 /* Copy 33 vec registers (vr0..31 and vscr) to the stack */
 222                 err |= __copy_to_user(v_regs, &current->thread.vr_state,
 223                                       33 * sizeof(vector128));
 224                 /* If VEC was enabled there are transactional VRs valid too,
 225                  * else they're a copy of the checkpointed VRs.
 226                  */
 227                 if (msr & MSR_VEC)
 228                         err |= __copy_to_user(tm_v_regs,
 229                                               &current->thread.transact_vr,
 230                                               33 * sizeof(vector128));
 231                 else
 232                         err |= __copy_to_user(tm_v_regs,
 233                                               &current->thread.vr_state,
 234                                               33 * sizeof(vector128));
 235
 236                 /* set MSR_VEC in the MSR value in the frame to indicate
 237                  * that sc->v_reg contains valid data.
 238                  */
 239                 msr |= MSR_VEC;
 240         }
 241         /* We always copy to/from vrsave, it's 0 if we don't have or don't
 242          * use altivec.
 243          */
 244         if (cpu_has_feature(CPU_FTR_ALTIVEC))
 245                 current->thread.vrsave = mfspr(SPRN_VRSAVE);
 246         err |= __put_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
 247         if (msr & MSR_VEC)
 248                 err |= __put_user(current->thread.transact_vrsave,
 249                                   (u32 __user *)&tm_v_regs[33]);
 250         else
 251                 err |= __put_user(current->thread.vrsave,
 252                                   (u32 __user *)&tm_v_regs[33]);
 253
 254 #else /* CONFIG_ALTIVEC */
 255         err |= __put_user(0, &sc->v_regs);
 256         err |= __put_user(0, &tm_sc->v_regs);
 257 #endif /* CONFIG_ALTIVEC */
 258
 259         /* copy fpr regs and fpscr */
 260         err |= copy_fpr_to_user(&sc->fp_regs, current);
 261         if (msr & MSR_FP)
 262                 err |= copy_transact_fpr_to_user(&tm_sc->fp_regs, current);
 263         else
 264                 err |= copy_fpr_to_user(&tm_sc->fp_regs, current);
 265
 266 #ifdef CONFIG_VSX
 267         /*
 268          * Copy VSX low doubleword to local buffer for formatting,
 269          * then out to userspace.  Update v_regs to point after the
 270          * VMX data.
 271          */
 272         if (current->thread.used_vsr) {
 273                 __giveup_vsx(current);
 274                 v_regs += ELF_NVRREG;
 275                 tm_v_regs += ELF_NVRREG;
 276
 277                 err |= copy_vsx_to_user(v_regs, current);
 278
 279                 if (msr & MSR_VSX)
 280                         err |= copy_transact_vsx_to_user(tm_v_regs, current);
 281                 else
 282                         err |= copy_vsx_to_user(tm_v_regs, current);
 283
 284                 /* set MSR_VSX in the MSR value in the frame to
 285                  * indicate that sc->vs_reg) contains valid data.
 286                  */
 287                 msr |= MSR_VSX;
 288         }
 289 #endif /* CONFIG_VSX */
 290
 291         err |= __put_user(&sc->gp_regs, &sc->regs);
 292         err |= __put_user(&tm_sc->gp_regs, &tm_sc->regs);
 293         WARN_ON(!FULL_REGS(regs));
 294         err |= __copy_to_user(&tm_sc->gp_regs, regs, GP_REGS_SIZE);
 295         err |= __copy_to_user(&sc->gp_regs,
 296                               &current->thread.ckpt_regs, GP_REGS_SIZE);
 297         err |= __put_user(msr, &tm_sc->gp_regs[PT_MSR]);
 298         err |= __put_user(msr, &sc->gp_regs[PT_MSR]);
 299         err |= __put_user(signr, &sc->signal);
 300         err |= __put_user(handler, &sc->handler);
 301         if (set != NULL)
 302                 err |=  __put_user(set->sig[0], &sc->oldmask);
 303
 304         return err;
 305 }
 306 #endif
 307
 308 /*
 309  * Restore the sigcontext from the signal frame.
 310  */
 311
 312 static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig,
 313                               struct sigcontext __user *sc)
 314 {
 315 #ifdef CONFIG_ALTIVEC
 316         elf_vrreg_t __user *v_regs;
 317 #endif
 318         unsigned long err = 0;
 319         unsigned long save_r13 = 0;
 320         unsigned long msr;
 321 #ifdef CONFIG_VSX
 322         int i;
 323 #endif
 324
 325         /* If this is not a signal return, we preserve the TLS in r13 */
 326         if (!sig)
 327                 save_r13 = regs->gpr[13];
 328
 329         /* copy the GPRs */
 330         err |= __copy_from_user(regs->gpr, sc->gp_regs, sizeof(regs->gpr));
 331         err |= __get_user(regs->nip, &sc->gp_regs[PT_NIP]);
 332         /* get MSR separately, transfer the LE bit if doing signal return */
 333         err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
 334         if (sig)
 335                 regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);
 336         err |= __get_user(regs->orig_gpr3, &sc->gp_regs[PT_ORIG_R3]);
 337         err |= __get_user(regs->ctr, &sc->gp_regs[PT_CTR]);
 338         err |= __get_user(regs->link, &sc->gp_regs[PT_LNK]);
 339         err |= __get_user(regs->xer, &sc->gp_regs[PT_XER]);
 340         err |= __get_user(regs->ccr, &sc->gp_regs[PT_CCR]);
 341         /* skip SOFTE */
 342         regs->trap = 0;
 343         err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]);
 344         err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]);
 345         err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]);
 346
 347         if (!sig)
 348                 regs->gpr[13] = save_r13;
 349         if (set != NULL)
 350                 err |=  __get_user(set->sig[0], &sc->oldmask);
 351
 352         /*
 353          * Do this before updating the thread state in
 354          * current->thread.fpr/vr.  That way, if we get preempted
 355          * and another task grabs the FPU/Altivec, it won't be
 356          * tempted to save the current CPU state into the thread_struct
 357          * and corrupt what we are writing there.
 358          */
 359         discard_lazy_cpu_state();
 360
 361         /*
 362          * Force reload of FP/VEC.
 363          * This has to be done before copying stuff into current->thread.fpr/vr
 364          * for the reasons explained in the previous comment.
 365          */
 366         regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX);
 367
 368 #ifdef CONFIG_ALTIVEC
 369         err |= __get_user(v_regs, &sc->v_regs);
 370         if (err)
 371                 return err;
 372         if (v_regs && !access_ok(VERIFY_READ, v_regs, 34 * sizeof(vector128)))
 373                 return -EFAULT;
 374         /* Copy 33 vec registers (vr0..31 and vscr) from the stack */
 375         if (v_regs != NULL && (msr & MSR_VEC) != 0)
 376                 err |= __copy_from_user(&current->thread.vr_state, v_regs,
 377                                         33 * sizeof(vector128));
 378         else if (current->thread.used_vr)
 379                 memset(&current->thread.vr_state, 0, 33 * sizeof(vector128));
 380         /* Always get VRSAVE back */
 381         if (v_regs != NULL)
 382                 err |= __get_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
 383         else
 384                 current->thread.vrsave = 0;
 385         if (cpu_has_feature(CPU_FTR_ALTIVEC))
 386                 mtspr(SPRN_VRSAVE, current->thread.vrsave);
 387 #endif /* CONFIG_ALTIVEC */
 388         /* restore floating point */
 389         err |= copy_fpr_from_user(current, &sc->fp_regs);
 390 #ifdef CONFIG_VSX
 391         /*
 392          * Get additional VSX data. Update v_regs to point after the
 393          * VMX data.  Copy VSX low doubleword from userspace to local
 394          * buffer for formatting, then into the taskstruct.
 395          */
 396         v_regs += ELF_NVRREG;
 397         if ((msr & MSR_VSX) != 0)
 398                 err |= copy_vsx_from_user(current, v_regs);
 399         else
 400                 for (i = 0; i < 32 ; i++)
 401                         current->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
 402 #endif
 403         return err;
 404 }
 405
 406 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 407 /*
 408  * Restore the two sigcontexts from the frame of a transactional processes.
 409  */
 410
 411 static long restore_tm_sigcontexts(struct pt_regs *regs,
 412                                    struct sigcontext __user *sc,
 413                                    struct sigcontext __user *tm_sc)
 414 {
 415 #ifdef CONFIG_ALTIVEC
 416         elf_vrreg_t __user *v_regs, *tm_v_regs;
 417 #endif
 418         unsigned long err = 0;
 419         unsigned long msr;
 420 #ifdef CONFIG_VSX
 421         int i;
 422 #endif
 423         /* copy the GPRs */
 424         err |= __copy_from_user(regs->gpr, tm_sc->gp_regs, sizeof(regs->gpr));
 425         err |= __copy_from_user(&current->thread.ckpt_regs, sc->gp_regs,
 426                                 sizeof(regs->gpr));
 427
 428         /*
 429          * TFHAR is restored from the checkpointed 'wound-back' ucontext's NIP.
 430          * TEXASR was set by the signal delivery reclaim, as was TFIAR.
 431          * Users doing anything abhorrent like thread-switching w/ signals for
 432          * TM-Suspended code will have to back TEXASR/TFIAR up themselves.
 433          * For the case of getting a signal and simply returning from it,
 434          * we don't need to re-copy them here.
 435          */
 436         err |= __get_user(regs->nip, &tm_sc->gp_regs[PT_NIP]);
 437         err |= __get_user(current->thread.tm_tfhar, &sc->gp_regs[PT_NIP]);
 438
 439         /* get MSR separately, transfer the LE bit if doing signal return */
 440         err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
 441         /* pull in MSR TM from user context */
 442         regs->msr = (regs->msr & ~MSR_TS_MASK) | (msr & MSR_TS_MASK);
 443
 444         /* pull in MSR LE from user context */
 445         regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);
 446
 447         /* The following non-GPR non-FPR non-VR state is also checkpointed: */
 448         err |= __get_user(regs->ctr, &tm_sc->gp_regs[PT_CTR]);
 449         err |= __get_user(regs->link, &tm_sc->gp_regs[PT_LNK]);
 450         err |= __get_user(regs->xer, &tm_sc->gp_regs[PT_XER]);
 451         err |= __get_user(regs->ccr, &tm_sc->gp_regs[PT_CCR]);
 452         err |= __get_user(current->thread.ckpt_regs.ctr,
 453                           &sc->gp_regs[PT_CTR]);
 454         err |= __get_user(current->thread.ckpt_regs.link,
 455                           &sc->gp_regs[PT_LNK]);
 456         err |= __get_user(current->thread.ckpt_regs.xer,
 457                           &sc->gp_regs[PT_XER]);
 458         err |= __get_user(current->thread.ckpt_regs.ccr,
 459                           &sc->gp_regs[PT_CCR]);
 460
 461         /* These regs are not checkpointed; they can go in 'regs'. */
 462         err |= __get_user(regs->trap, &sc->gp_regs[PT_TRAP]);
 463         err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]);
 464         err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]);
 465         err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]);
 466
 467         /*
 468          * Do this before updating the thread state in
 469          * current->thread.fpr/vr.  That way, if we get preempted
 470          * and another task grabs the FPU/Altivec, it won't be
 471          * tempted to save the current CPU state into the thread_struct
 472          * and corrupt what we are writing there.
 473          */
 474         discard_lazy_cpu_state();
 475
 476         /*
 477          * Force reload of FP/VEC.
 478          * This has to be done before copying stuff into current->thread.fpr/vr
 479          * for the reasons explained in the previous comment.
 480          */
 481         regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX);
 482
 483 #ifdef CONFIG_ALTIVEC
 484         err |= __get_user(v_regs, &sc->v_regs);
 485         err |= __get_user(tm_v_regs, &tm_sc->v_regs);
 486         if (err)
 487                 return err;
 488         if (v_regs && !access_ok(VERIFY_READ, v_regs, 34 * sizeof(vector128)))
 489                 return -EFAULT;
 490         if (tm_v_regs && !access_ok(VERIFY_READ,
 491                                     tm_v_regs, 34 * sizeof(vector128)))
 492                 return -EFAULT;
 493         /* Copy 33 vec registers (vr0..31 and vscr) from the stack */
 494         if (v_regs != NULL && tm_v_regs != NULL && (msr & MSR_VEC) != 0) {
 495                 err |= __copy_from_user(&current->thread.vr_state, v_regs,
 496                                         33 * sizeof(vector128));
 497                 err |= __copy_from_user(&current->thread.transact_vr, tm_v_regs,
 498                                         33 * sizeof(vector128));
 499         }
 500         else if (current->thread.used_vr) {
 501                 memset(&current->thread.vr_state, 0, 33 * sizeof(vector128));
 502                 memset(&current->thread.transact_vr, 0, 33 * sizeof(vector128));
 503         }
 504         /* Always get VRSAVE back */
 505         if (v_regs != NULL && tm_v_regs != NULL) {
 506                 err |= __get_user(current->thread.vrsave,
 507                                   (u32 __user *)&v_regs[33]);
 508                 err |= __get_user(current->thread.transact_vrsave,
 509                                   (u32 __user *)&tm_v_regs[33]);
 510         }
 511         else {
 512                 current->thread.vrsave = 0;
 513                 current->thread.transact_vrsave = 0;
 514         }
 515         if (cpu_has_feature(CPU_FTR_ALTIVEC))
 516                 mtspr(SPRN_VRSAVE, current->thread.vrsave);
 517 #endif /* CONFIG_ALTIVEC */
 518         /* restore floating point */
 519         err |= copy_fpr_from_user(current, &sc->fp_regs);
 520         err |= copy_transact_fpr_from_user(current, &tm_sc->fp_regs);
 521 #ifdef CONFIG_VSX
 522         /*
 523          * Get additional VSX data. Update v_regs to point after the
 524          * VMX data.  Copy VSX low doubleword from userspace to local
 525          * buffer for formatting, then into the taskstruct.
 526          */
 527         if (v_regs && ((msr & MSR_VSX) != 0)) {
 528                 v_regs += ELF_NVRREG;
 529                 tm_v_regs += ELF_NVRREG;
 530                 err |= copy_vsx_from_user(current, v_regs);
 531                 err |= copy_transact_vsx_from_user(current, tm_v_regs);
 532         } else {
 533                 for (i = 0; i < 32 ; i++) {
 534                         current->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
 535                         current->thread.transact_fp.fpr[i][TS_VSRLOWOFFSET] = 0;
 536                 }
 537         }
 538 #endif
 539         tm_enable();
 540         /* Make sure the transaction is marked as failed */
 541         current->thread.tm_texasr |= TEXASR_FS;
 542         /* This loads the checkpointed FP/VEC state, if used */
 543         tm_recheckpoint(&current->thread, msr);
 544
 545         /* This loads the speculative FP/VEC state, if used */
 546         if (msr & MSR_FP) {
 547                 do_load_up_transact_fpu(&current->thread);
 548                 regs->msr |= (MSR_FP | current->thread.fpexc_mode);
 549         }
 550 #ifdef CONFIG_ALTIVEC
 551         if (msr & MSR_VEC) {
 552                 do_load_up_transact_altivec(&current->thread);
 553                 regs->msr |= MSR_VEC;
 554         }
 555 #endif
 556
 557         return err;
 558 }
 559 #endif
 560
 561 /*
 562  * Setup the trampoline code on the stack
 563  */
 564 static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp)
 565 {
 566         int i;
 567         long err = 0;
 568
 569         /* addi r1, r1, __SIGNAL_FRAMESIZE  # Pop the dummy stackframe */
 570         err |= __put_user(0x38210000UL | (__SIGNAL_FRAMESIZE & 0xffff), &tramp[0]);
 571         /* li r0, __NR_[rt_]sigreturn| */
 572         err |= __put_user(0x38000000UL | (syscall & 0xffff), &tramp[1]);
 573         /* sc */
 574         err |= __put_user(0x44000002UL, &tramp[2]);
 575
 576         /* Minimal traceback info */
 577         for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++)
 578                 err |= __put_user(0, &tramp[i]);
 579
 580         if (!err)
 581                 flush_icache_range((unsigned long) &tramp[0],
 582                            (unsigned long) &tramp[TRAMP_SIZE]);
 583
 584         return err;
 585 }
 586
 587 /*
 588  * Userspace code may pass a ucontext which doesn't include VSX added
 589  * at the end.  We need to check for this case.
 590  */
 591 #define UCONTEXTSIZEWITHOUTVSX \
 592                 (sizeof(struct ucontext) - 32*sizeof(long))
 593
 594 /*
 595  * Handle {get,set,swap}_context operations
 596  */
 597 int sys_swapcontext(struct ucontext __user *old_ctx,
 598                     struct ucontext __user *new_ctx,
 599                     long ctx_size, long r6, long r7, long r8, struct pt_regs *regs)
 600 {
 601         unsigned char tmp;
 602         sigset_t set;
 603         unsigned long new_msr = 0;
 604         int ctx_has_vsx_region = 0;
 605
 606         if (new_ctx &&
 607             get_user(new_msr, &new_ctx->uc_mcontext.gp_regs[PT_MSR]))
 608                 return -EFAULT;
 609         /*
 610          * Check that the context is not smaller than the original
 611          * size (with VMX but without VSX)
 612          */
 613         if (ctx_size < UCONTEXTSIZEWITHOUTVSX)
 614                 return -EINVAL;
 615         /*
 616          * If the new context state sets the MSR VSX bits but
 617          * it doesn't provide VSX state.
 618          */
 619         if ((ctx_size < sizeof(struct ucontext)) &&
 620             (new_msr & MSR_VSX))
 621                 return -EINVAL;
 622         /* Does the context have enough room to store VSX data? */
 623         if (ctx_size >= sizeof(struct ucontext))
 624                 ctx_has_vsx_region = 1;
 625
 626         if (old_ctx != NULL) {
 627                 if (!access_ok(VERIFY_WRITE, old_ctx, ctx_size)
 628                     || setup_sigcontext(&old_ctx->uc_mcontext, regs, 0, NULL, 0,
 629                                         ctx_has_vsx_region)
 630                     || __copy_to_user(&old_ctx->uc_sigmask,
 631                                       &current->blocked, sizeof(sigset_t)))
 632                         return -EFAULT;
 633         }
 634         if (new_ctx == NULL)
 635                 return 0;
 636         if (!access_ok(VERIFY_READ, new_ctx, ctx_size)
 637             || __get_user(tmp, (u8 __user *) new_ctx)
 638             || __get_user(tmp, (u8 __user *) new_ctx + ctx_size - 1))
 639                 return -EFAULT;
 640
 641         /*
 642          * If we get a fault copying the context into the kernel's
 643          * image of the user's registers, we can't just return -EFAULT
 644          * because the user's registers will be corrupted.  For instance
 645          * the NIP value may have been updated but not some of the
 646          * other registers.  Given that we have done the access_ok
 647          * and successfully read the first and last bytes of the region
 648          * above, this should only happen in an out-of-memory situation
 649          * or if another thread unmaps the region containing the context.
 650          * We kill the task with a SIGSEGV in this situation.
 651          */
 652
 653         if (__copy_from_user(&set, &new_ctx->uc_sigmask, sizeof(set)))
 654                 do_exit(SIGSEGV);
 655         set_current_blocked(&set);
 656         if (restore_sigcontext(regs, NULL, 0, &new_ctx->uc_mcontext))
 657                 do_exit(SIGSEGV);
 658
 659         /* This returns like rt_sigreturn */
 660         set_thread_flag(TIF_RESTOREALL);
 661         return 0;
 662 }
 663
 664
 665 /*
 666  * Do a signal return; undo the signal stack.
 667  */
 668
 669 int sys_rt_sigreturn(unsigned long r3, unsigned long r4, unsigned long r5,
 670                      unsigned long r6, unsigned long r7, unsigned long r8,
 671                      struct pt_regs *regs)
 672 {
 673         struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1];
 674         sigset_t set;
 675 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 676         unsigned long msr;
 677 #endif
 678
 679         /* Always make any pending restarted system calls return -EINTR */
 680         current->restart_block.fn = do_no_restart_syscall;
 681
 682         if (!access_ok(VERIFY_READ, uc, sizeof(*uc)))
 683                 goto badframe;
 684
 685         if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
 686                 goto badframe;
 687         set_current_blocked(&set);
 688 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 689         if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR]))
 690                 goto badframe;
 691         if (MSR_TM_ACTIVE(msr)) {
 692                 /* We recheckpoint on return. */
 693                 struct ucontext __user *uc_transact;
 694                 if (__get_user(uc_transact, &uc->uc_link))
 695                         goto badframe;
 696                 if (restore_tm_sigcontexts(regs, &uc->uc_mcontext,
 697                                            &uc_transact->uc_mcontext))
 698                         goto badframe;
 699         }
 700         else
 701         /* Fall through, for non-TM restore */
 702 #endif
 703         if (restore_sigcontext(regs, NULL, 1, &uc->uc_mcontext))
 704                 goto badframe;
 705
 706         if (restore_altstack(&uc->uc_stack))
 707                 goto badframe;
 708
 709         set_thread_flag(TIF_RESTOREALL);
 710         return 0;
 711
 712 badframe:
 713         if (show_unhandled_signals)
 714                 printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32,
 715                                    current->comm, current->pid, "rt_sigreturn",
 716                                    (long)uc, regs->nip, regs->link);
 717
 718         force_sig(SIGSEGV, current);
 719         return 0;
 720 }
 721
 722 int handle_rt_signal64(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
 723 {
 724         struct rt_sigframe __user *frame;
 725         unsigned long newsp = 0;
 726         long err = 0;
 727
 728         frame = get_sigframe(ksig, get_tm_stackpointer(regs), sizeof(*frame), 0);
 729         if (unlikely(frame == NULL))
 730                 goto badframe;
 731
 732         err |= __put_user(&frame->info, &frame->pinfo);
 733         err |= __put_user(&frame->uc, &frame->puc);
 734         err |= copy_siginfo_to_user(&frame->info, &ksig->info);
 735         if (err)
 736                 goto badframe;
 737
 738         /* Create the ucontext.  */
 739         err |= __put_user(0, &frame->uc.uc_flags);
 740         err |= __save_altstack(&frame->uc.uc_stack, regs->gpr[1]);
 741 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 742         if (MSR_TM_ACTIVE(regs->msr)) {
 743                 /* The ucontext_t passed to userland points to the second
 744                  * ucontext_t (for transactional state) with its uc_link ptr.
 745                  */
 746                 err |= __put_user(&frame->uc_transact, &frame->uc.uc_link);
 747                 err |= setup_tm_sigcontexts(&frame->uc.uc_mcontext,
 748                                             &frame->uc_transact.uc_mcontext,
 749                                             regs, ksig->sig,
 750                                             NULL,
 751                                             (unsigned long)ksig->ka.sa.sa_handler);
 752         } else
 753 #endif
 754         {
 755                 err |= __put_user(0, &frame->uc.uc_link);
 756                 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, ksig->sig,
 757                                         NULL, (unsigned long)ksig->ka.sa.sa_handler,
 758                                         1);
 759         }
 760         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 761         if (err)
 762                 goto badframe;
 763
 764         /* Make sure signal handler doesn't get spurious FP exceptions */
 765         current->thread.fp_state.fpscr = 0;
 766
 767         /* Set up to return from userspace. */
 768         if (vdso64_rt_sigtramp && current->mm->context.vdso_base) {
 769                 regs->link = current->mm->context.vdso_base + vdso64_rt_sigtramp;
 770         } else {
 771                 err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]);
 772                 if (err)
 773                         goto badframe;
 774                 regs->link = (unsigned long) &frame->tramp[0];
 775         }
 776
 777         /* Allocate a dummy caller frame for the signal handler. */
 778         newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE;
 779         err |= put_user(regs->gpr[1], (unsigned long __user *)newsp);
 780
 781         /* Set up "regs" so we "return" to the signal handler. */
 782         if (is_elf2_task()) {
 783                 regs->nip = (unsigned long) ksig->ka.sa.sa_handler;
 784                 regs->gpr[12] = regs->nip;
 785         } else {
 786                 /* Handler is *really* a pointer to the function descriptor for
 787                  * the signal routine.  The first entry in the function
 788                  * descriptor is the entry address of signal and the second
 789                  * entry is the TOC value we need to use.
 790                  */
 791                 func_descr_t __user *funct_desc_ptr =
 792                         (func_descr_t __user *) ksig->ka.sa.sa_handler;
 793
 794                 err |= get_user(regs->nip, &funct_desc_ptr->entry);
 795                 err |= get_user(regs->gpr[2], &funct_desc_ptr->toc);
 796         }
 797
 798         /* enter the signal handler in native-endian mode */
 799         regs->msr &= ~MSR_LE;
 800         regs->msr |= (MSR_KERNEL & MSR_LE);
 801         regs->gpr[1] = newsp;
 802         regs->gpr[3] = ksig->sig;
 803         regs->result = 0;
 804         if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
 805                 err |= get_user(regs->gpr[4], (unsigned long __user *)&frame->pinfo);
 806                 err |= get_user(regs->gpr[5], (unsigned long __user *)&frame->puc);
 807                 regs->gpr[6] = (unsigned long) frame;
 808         } else {
 809                 regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext;
 810         }
 811         if (err)
 812                 goto badframe;
 813
 814         return 0;
 815
 816 badframe:
 817         if (show_unhandled_signals)
 818                 printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32,
 819                                    current->comm, current->pid, "setup_rt_frame",
 820                                    (long)frame, regs->nip, regs->link);
 821
 822         return 1;
 823 }