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 {
 197         /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the
 198          * process never used altivec yet (MSR_VEC is zero in pt_regs of
 199          * the context). This is very important because we must ensure we
 200          * don't lose the VRSAVE content that may have been set prior to
 201          * the process doing its first vector operation
 202          * Userland shall check AT_HWCAP to know wether it can rely on the
 203          * v_regs pointer or not.
 204          */
 205 #ifdef CONFIG_ALTIVEC
 206         elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc);
 207         elf_vrreg_t __user *tm_v_regs = sigcontext_vmx_regs(tm_sc);
 208 #endif
 209         struct pt_regs *regs = tsk->thread.regs;
 210         unsigned long msr = tsk->thread.regs->msr;
 211         long err = 0;
 212
 213         BUG_ON(tsk != current);
 214
 215         BUG_ON(!MSR_TM_ACTIVE(regs->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         /* Remove TM bits from thread's MSR.  The MSR in the sigcontext
 226          * just indicates to userland that we were doing a transaction, but we
 227          * don't want to return in transactional state.  This also ensures
 228          * that flush_fp_to_thread won't set TIF_RESTORE_TM again.
 229          */
 230         regs->msr &= ~MSR_TS_MASK;
 231
 232 #ifdef CONFIG_ALTIVEC
 233         err |= __put_user(v_regs, &sc->v_regs);
 234         err |= __put_user(tm_v_regs, &tm_sc->v_regs);
 235
 236         /* save altivec registers */
 237         if (tsk->thread.used_vr) {
 238                 /* Copy 33 vec registers (vr0..31 and vscr) to the stack */
 239                 err |= __copy_to_user(v_regs, &tsk->thread.ckvr_state,
 240                                       33 * sizeof(vector128));
 241                 /* If VEC was enabled there are transactional VRs valid too,
 242                  * else they're a copy of the checkpointed VRs.
 243                  */
 244                 if (msr & MSR_VEC)
 245                         err |= __copy_to_user(tm_v_regs,
 246                                               &tsk->thread.vr_state,
 247                                               33 * sizeof(vector128));
 248                 else
 249                         err |= __copy_to_user(tm_v_regs,
 250                                               &tsk->thread.ckvr_state,
 251                                               33 * sizeof(vector128));
 252
 253                 /* set MSR_VEC in the MSR value in the frame to indicate
 254                  * that sc->v_reg contains valid data.
 255                  */
 256                 msr |= MSR_VEC;
 257         }
 258         /* We always copy to/from vrsave, it's 0 if we don't have or don't
 259          * use altivec.
 260          */
 261         if (cpu_has_feature(CPU_FTR_ALTIVEC))
 262                 tsk->thread.ckvrsave = mfspr(SPRN_VRSAVE);
 263         err |= __put_user(tsk->thread.ckvrsave, (u32 __user *)&v_regs[33]);
 264         if (msr & MSR_VEC)
 265                 err |= __put_user(tsk->thread.vrsave,
 266                                   (u32 __user *)&tm_v_regs[33]);
 267         else
 268                 err |= __put_user(tsk->thread.ckvrsave,
 269                                   (u32 __user *)&tm_v_regs[33]);
 270
 271 #else /* CONFIG_ALTIVEC */
 272         err |= __put_user(0, &sc->v_regs);
 273         err |= __put_user(0, &tm_sc->v_regs);
 274 #endif /* CONFIG_ALTIVEC */
 275
 276         /* copy fpr regs and fpscr */
 277         err |= copy_ckfpr_to_user(&sc->fp_regs, tsk);
 278         if (msr & MSR_FP)
 279                 err |= copy_fpr_to_user(&tm_sc->fp_regs, tsk);
 280         else
 281                 err |= copy_ckfpr_to_user(&tm_sc->fp_regs, tsk);
 282
 283 #ifdef CONFIG_VSX
 284         /*
 285          * Copy VSX low doubleword to local buffer for formatting,
 286          * then out to userspace.  Update v_regs to point after the
 287          * VMX data.
 288          */
 289         if (tsk->thread.used_vsr) {
 290                 v_regs += ELF_NVRREG;
 291                 tm_v_regs += ELF_NVRREG;
 292
 293                 err |= copy_ckvsx_to_user(v_regs, tsk);
 294
 295                 if (msr & MSR_VSX)
 296                         err |= copy_vsx_to_user(tm_v_regs, tsk);
 297                 else
 298                         err |= copy_ckvsx_to_user(tm_v_regs, tsk);
 299
 300                 /* set MSR_VSX in the MSR value in the frame to
 301                  * indicate that sc->vs_reg) contains valid data.
 302                  */
 303                 msr |= MSR_VSX;
 304         }
 305 #endif /* CONFIG_VSX */
 306
 307         err |= __put_user(&sc->gp_regs, &sc->regs);
 308         err |= __put_user(&tm_sc->gp_regs, &tm_sc->regs);
 309         WARN_ON(!FULL_REGS(regs));
 310         err |= __copy_to_user(&tm_sc->gp_regs, regs, GP_REGS_SIZE);
 311         err |= __copy_to_user(&sc->gp_regs,
 312                               &tsk->thread.ckpt_regs, GP_REGS_SIZE);
 313         err |= __put_user(msr, &tm_sc->gp_regs[PT_MSR]);
 314         err |= __put_user(msr, &sc->gp_regs[PT_MSR]);
 315         err |= __put_user(signr, &sc->signal);
 316         err |= __put_user(handler, &sc->handler);
 317         if (set != NULL)
 318                 err |=  __put_user(set->sig[0], &sc->oldmask);
 319
 320         return err;
 321 }
 322 #endif
 323
 324 /*
 325  * Restore the sigcontext from the signal frame.
 326  */
 327
 328 static long restore_sigcontext(struct task_struct *tsk, sigset_t *set, int sig,
 329                               struct sigcontext __user *sc)
 330 {
 331 #ifdef CONFIG_ALTIVEC
 332         elf_vrreg_t __user *v_regs;
 333 #endif
 334         unsigned long err = 0;
 335         unsigned long save_r13 = 0;
 336         unsigned long msr;
 337         struct pt_regs *regs = tsk->thread.regs;
 338 #ifdef CONFIG_VSX
 339         int i;
 340 #endif
 341
 342         BUG_ON(tsk != current);
 343
 344         /* If this is not a signal return, we preserve the TLS in r13 */
 345         if (!sig)
 346                 save_r13 = regs->gpr[13];
 347
 348         /* copy the GPRs */
 349         err |= __copy_from_user(regs->gpr, sc->gp_regs, sizeof(regs->gpr));
 350         err |= __get_user(regs->nip, &sc->gp_regs[PT_NIP]);
 351         /* get MSR separately, transfer the LE bit if doing signal return */
 352         err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
 353         if (sig)
 354                 regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);
 355         err |= __get_user(regs->orig_gpr3, &sc->gp_regs[PT_ORIG_R3]);
 356         err |= __get_user(regs->ctr, &sc->gp_regs[PT_CTR]);
 357         err |= __get_user(regs->link, &sc->gp_regs[PT_LNK]);
 358         err |= __get_user(regs->xer, &sc->gp_regs[PT_XER]);
 359         err |= __get_user(regs->ccr, &sc->gp_regs[PT_CCR]);
 360         /* skip SOFTE */
 361         regs->trap = 0;
 362         err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]);
 363         err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]);
 364         err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]);
 365
 366         if (!sig)
 367                 regs->gpr[13] = save_r13;
 368         if (set != NULL)
 369                 err |=  __get_user(set->sig[0], &sc->oldmask);
 370
 371         /*
 372          * Force reload of FP/VEC.
 373          * This has to be done before copying stuff into tsk->thread.fpr/vr
 374          * for the reasons explained in the previous comment.
 375          */
 376         regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX);
 377
 378 #ifdef CONFIG_ALTIVEC
 379         err |= __get_user(v_regs, &sc->v_regs);
 380         if (err)
 381                 return err;
 382         if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128)))
 383                 return -EFAULT;
 384         /* Copy 33 vec registers (vr0..31 and vscr) from the stack */
 385         if (v_regs != NULL && (msr & MSR_VEC) != 0) {
 386                 err |= __copy_from_user(&tsk->thread.vr_state, v_regs,
 387                                         33 * sizeof(vector128));
 388                 tsk->thread.used_vr = true;
 389         } else if (tsk->thread.used_vr) {
 390                 memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128));
 391         }
 392         /* Always get VRSAVE back */
 393         if (v_regs != NULL)
 394                 err |= __get_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33]);
 395         else
 396                 tsk->thread.vrsave = 0;
 397         if (cpu_has_feature(CPU_FTR_ALTIVEC))
 398                 mtspr(SPRN_VRSAVE, tsk->thread.vrsave);
 399 #endif /* CONFIG_ALTIVEC */
 400         /* restore floating point */
 401         err |= copy_fpr_from_user(tsk, &sc->fp_regs);
 402 #ifdef CONFIG_VSX
 403         /*
 404          * Get additional VSX data. Update v_regs to point after the
 405          * VMX data.  Copy VSX low doubleword from userspace to local
 406          * buffer for formatting, then into the taskstruct.
 407          */
 408         v_regs += ELF_NVRREG;
 409         if ((msr & MSR_VSX) != 0) {
 410                 err |= copy_vsx_from_user(tsk, v_regs);
 411                 tsk->thread.used_vsr = true;
 412         } else {
 413                 for (i = 0; i < 32 ; i++)
 414                         tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
 415         }
 416 #endif
 417         return err;
 418 }
 419
 420 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 421 /*
 422  * Restore the two sigcontexts from the frame of a transactional processes.
 423  */
 424
 425 static long restore_tm_sigcontexts(struct task_struct *tsk,
 426                                    struct sigcontext __user *sc,
 427                                    struct sigcontext __user *tm_sc)
 428 {
 429 #ifdef CONFIG_ALTIVEC
 430         elf_vrreg_t __user *v_regs, *tm_v_regs;
 431 #endif
 432         unsigned long err = 0;
 433         unsigned long msr;
 434         struct pt_regs *regs = tsk->thread.regs;
 435 #ifdef CONFIG_VSX
 436         int i;
 437 #endif
 438
 439         BUG_ON(tsk != current);
 440
 441         if (tm_suspend_disabled)
 442                 return -EINVAL;
 443
 444         /* copy the GPRs */
 445         err |= __copy_from_user(regs->gpr, tm_sc->gp_regs, sizeof(regs->gpr));
 446         err |= __copy_from_user(&tsk->thread.ckpt_regs, sc->gp_regs,
 447                                 sizeof(regs->gpr));
 448
 449         /*
 450          * TFHAR is restored from the checkpointed 'wound-back' ucontext's NIP.
 451          * TEXASR was set by the signal delivery reclaim, as was TFIAR.
 452          * Users doing anything abhorrent like thread-switching w/ signals for
 453          * TM-Suspended code will have to back TEXASR/TFIAR up themselves.
 454          * For the case of getting a signal and simply returning from it,
 455          * we don't need to re-copy them here.
 456          */
 457         err |= __get_user(regs->nip, &tm_sc->gp_regs[PT_NIP]);
 458         err |= __get_user(tsk->thread.tm_tfhar, &sc->gp_regs[PT_NIP]);
 459
 460         /* get MSR separately, transfer the LE bit if doing signal return */
 461         err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
 462         /* Don't allow reserved mode. */
 463         if (MSR_TM_RESV(msr))
 464                 return -EINVAL;
 465
 466         /* pull in MSR LE from user context */
 467         regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);
 468
 469         /* The following non-GPR non-FPR non-VR state is also checkpointed: */
 470         err |= __get_user(regs->ctr, &tm_sc->gp_regs[PT_CTR]);
 471         err |= __get_user(regs->link, &tm_sc->gp_regs[PT_LNK]);
 472         err |= __get_user(regs->xer, &tm_sc->gp_regs[PT_XER]);
 473         err |= __get_user(regs->ccr, &tm_sc->gp_regs[PT_CCR]);
 474         err |= __get_user(tsk->thread.ckpt_regs.ctr,
 475                           &sc->gp_regs[PT_CTR]);
 476         err |= __get_user(tsk->thread.ckpt_regs.link,
 477                           &sc->gp_regs[PT_LNK]);
 478         err |= __get_user(tsk->thread.ckpt_regs.xer,
 479                           &sc->gp_regs[PT_XER]);
 480         err |= __get_user(tsk->thread.ckpt_regs.ccr,
 481                           &sc->gp_regs[PT_CCR]);
 482
 483         /* These regs are not checkpointed; they can go in 'regs'. */
 484         err |= __get_user(regs->trap, &sc->gp_regs[PT_TRAP]);
 485         err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]);
 486         err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]);
 487         err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]);
 488
 489         /*
 490          * Force reload of FP/VEC.
 491          * This has to be done before copying stuff into tsk->thread.fpr/vr
 492          * for the reasons explained in the previous comment.
 493          */
 494         regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX);
 495
 496 #ifdef CONFIG_ALTIVEC
 497         err |= __get_user(v_regs, &sc->v_regs);
 498         err |= __get_user(tm_v_regs, &tm_sc->v_regs);
 499         if (err)
 500                 return err;
 501         if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128)))
 502                 return -EFAULT;
 503         if (tm_v_regs && !access_ok(tm_v_regs, 34 * sizeof(vector128)))
 504                 return -EFAULT;
 505         /* Copy 33 vec registers (vr0..31 and vscr) from the stack */
 506         if (v_regs != NULL && tm_v_regs != NULL && (msr & MSR_VEC) != 0) {
 507                 err |= __copy_from_user(&tsk->thread.ckvr_state, v_regs,
 508                                         33 * sizeof(vector128));
 509                 err |= __copy_from_user(&tsk->thread.vr_state, tm_v_regs,
 510                                         33 * sizeof(vector128));
 511                 current->thread.used_vr = true;
 512         }
 513         else if (tsk->thread.used_vr) {
 514                 memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128));
 515                 memset(&tsk->thread.ckvr_state, 0, 33 * sizeof(vector128));
 516         }
 517         /* Always get VRSAVE back */
 518         if (v_regs != NULL && tm_v_regs != NULL) {
 519                 err |= __get_user(tsk->thread.ckvrsave,
 520                                   (u32 __user *)&v_regs[33]);
 521                 err |= __get_user(tsk->thread.vrsave,
 522                                   (u32 __user *)&tm_v_regs[33]);
 523         }
 524         else {
 525                 tsk->thread.vrsave = 0;
 526                 tsk->thread.ckvrsave = 0;
 527         }
 528         if (cpu_has_feature(CPU_FTR_ALTIVEC))
 529                 mtspr(SPRN_VRSAVE, tsk->thread.vrsave);
 530 #endif /* CONFIG_ALTIVEC */
 531         /* restore floating point */
 532         err |= copy_fpr_from_user(tsk, &tm_sc->fp_regs);
 533         err |= copy_ckfpr_from_user(tsk, &sc->fp_regs);
 534 #ifdef CONFIG_VSX
 535         /*
 536          * Get additional VSX data. Update v_regs to point after the
 537          * VMX data.  Copy VSX low doubleword from userspace to local
 538          * buffer for formatting, then into the taskstruct.
 539          */
 540         if (v_regs && ((msr & MSR_VSX) != 0)) {
 541                 v_regs += ELF_NVRREG;
 542                 tm_v_regs += ELF_NVRREG;
 543                 err |= copy_vsx_from_user(tsk, tm_v_regs);
 544                 err |= copy_ckvsx_from_user(tsk, v_regs);
 545                 tsk->thread.used_vsr = true;
 546         } else {
 547                 for (i = 0; i < 32 ; i++) {
 548                         tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
 549                         tsk->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
 550                 }
 551         }
 552 #endif
 553         tm_enable();
 554         /* Make sure the transaction is marked as failed */
 555         tsk->thread.tm_texasr |= TEXASR_FS;
 556
 557         /*
 558          * Disabling preemption, since it is unsafe to be preempted
 559          * with MSR[TS] set without recheckpointing.
 560          */
 561         preempt_disable();
 562
 563         /* pull in MSR TS bits from user context */
 564         regs->msr |= msr & MSR_TS_MASK;
 565
 566         /*
 567          * Ensure that TM is enabled in regs->msr before we leave the signal
 568          * handler. It could be the case that (a) user disabled the TM bit
 569          * through the manipulation of the MSR bits in uc_mcontext or (b) the
 570          * TM bit was disabled because a sufficient number of context switches
 571          * happened whilst in the signal handler and load_tm overflowed,
 572          * disabling the TM bit. In either case we can end up with an illegal
 573          * TM state leading to a TM Bad Thing when we return to userspace.
 574          *
 575          * CAUTION:
 576          * After regs->MSR[TS] being updated, make sure that get_user(),
 577          * put_user() or similar functions are *not* called. These
 578          * functions can generate page faults which will cause the process
 579          * to be de-scheduled with MSR[TS] set but without calling
 580          * tm_recheckpoint(). This can cause a bug.
 581          */
 582         regs->msr |= MSR_TM;
 583
 584         /* This loads the checkpointed FP/VEC state, if used */
 585         tm_recheckpoint(&tsk->thread);
 586
 587         msr_check_and_set(msr & (MSR_FP | MSR_VEC));
 588         if (msr & MSR_FP) {
 589                 load_fp_state(&tsk->thread.fp_state);
 590                 regs->msr |= (MSR_FP | tsk->thread.fpexc_mode);
 591         }
 592         if (msr & MSR_VEC) {
 593                 load_vr_state(&tsk->thread.vr_state);
 594                 regs->msr |= MSR_VEC;
 595         }
 596
 597         preempt_enable();
 598
 599         return err;
 600 }
 601 #endif
 602
 603 /*
 604  * Setup the trampoline code on the stack
 605  */
 606 static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp)
 607 {
 608         int i;
 609         long err = 0;
 610
 611         /* addi r1, r1, __SIGNAL_FRAMESIZE  # Pop the dummy stackframe */
 612         err |= __put_user(PPC_INST_ADDI | __PPC_RT(R1) | __PPC_RA(R1) |
 613                           (__SIGNAL_FRAMESIZE & 0xffff), &tramp[0]);
 614         /* li r0, __NR_[rt_]sigreturn| */
 615         err |= __put_user(PPC_INST_ADDI | (syscall & 0xffff), &tramp[1]);
 616         /* sc */
 617         err |= __put_user(PPC_INST_SC, &tramp[2]);
 618
 619         /* Minimal traceback info */
 620         for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++)
 621                 err |= __put_user(0, &tramp[i]);
 622
 623         if (!err)
 624                 flush_icache_range((unsigned long) &tramp[0],
 625                            (unsigned long) &tramp[TRAMP_SIZE]);
 626
 627         return err;
 628 }
 629
 630 /*
 631  * Userspace code may pass a ucontext which doesn't include VSX added
 632  * at the end.  We need to check for this case.
 633  */
 634 #define UCONTEXTSIZEWITHOUTVSX \
 635                 (sizeof(struct ucontext) - 32*sizeof(long))
 636
 637 /*
 638  * Handle {get,set,swap}_context operations
 639  */
 640 SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx,
 641                 struct ucontext __user *, new_ctx, long, ctx_size)
 642 {
 643         unsigned char tmp;
 644         sigset_t set;
 645         unsigned long new_msr = 0;
 646         int ctx_has_vsx_region = 0;
 647
 648         if (new_ctx &&
 649             get_user(new_msr, &new_ctx->uc_mcontext.gp_regs[PT_MSR]))
 650                 return -EFAULT;
 651         /*
 652          * Check that the context is not smaller than the original
 653          * size (with VMX but without VSX)
 654          */
 655         if (ctx_size < UCONTEXTSIZEWITHOUTVSX)
 656                 return -EINVAL;
 657         /*
 658          * If the new context state sets the MSR VSX bits but
 659          * it doesn't provide VSX state.
 660          */
 661         if ((ctx_size < sizeof(struct ucontext)) &&
 662             (new_msr & MSR_VSX))
 663                 return -EINVAL;
 664         /* Does the context have enough room to store VSX data? */
 665         if (ctx_size >= sizeof(struct ucontext))
 666                 ctx_has_vsx_region = 1;
 667
 668         if (old_ctx != NULL) {
 669                 if (!access_ok(old_ctx, ctx_size)
 670                     || setup_sigcontext(&old_ctx->uc_mcontext, current, 0, NULL, 0,
 671                                         ctx_has_vsx_region)
 672                     || __copy_to_user(&old_ctx->uc_sigmask,
 673                                       &current->blocked, sizeof(sigset_t)))
 674                         return -EFAULT;
 675         }
 676         if (new_ctx == NULL)
 677                 return 0;
 678         if (!access_ok(new_ctx, ctx_size)
 679             || __get_user(tmp, (u8 __user *) new_ctx)
 680             || __get_user(tmp, (u8 __user *) new_ctx + ctx_size - 1))
 681                 return -EFAULT;
 682
 683         /*
 684          * If we get a fault copying the context into the kernel's
 685          * image of the user's registers, we can't just return -EFAULT
 686          * because the user's registers will be corrupted.  For instance
 687          * the NIP value may have been updated but not some of the
 688          * other registers.  Given that we have done the access_ok
 689          * and successfully read the first and last bytes of the region
 690          * above, this should only happen in an out-of-memory situation
 691          * or if another thread unmaps the region containing the context.
 692          * We kill the task with a SIGSEGV in this situation.
 693          */
 694
 695         if (__copy_from_user(&set, &new_ctx->uc_sigmask, sizeof(set)))
 696                 do_exit(SIGSEGV);
 697         set_current_blocked(&set);
 698         if (restore_sigcontext(current, NULL, 0, &new_ctx->uc_mcontext))
 699                 do_exit(SIGSEGV);
 700
 701         /* This returns like rt_sigreturn */
 702         set_thread_flag(TIF_RESTOREALL);
 703         return 0;
 704 }
 705
 706
 707 /*
 708  * Do a signal return; undo the signal stack.
 709  */
 710
 711 SYSCALL_DEFINE0(rt_sigreturn)
 712 {
 713         struct pt_regs *regs = current_pt_regs();
 714         struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1];
 715         sigset_t set;
 716 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 717         unsigned long msr;
 718 #endif
 719
 720         /* Always make any pending restarted system calls return -EINTR */
 721         current->restart_block.fn = do_no_restart_syscall;
 722
 723         if (!access_ok(uc, sizeof(*uc)))
 724                 goto badframe;
 725
 726         if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
 727                 goto badframe;
 728         set_current_blocked(&set);
 729
 730 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 731         /*
 732          * If there is a transactional state then throw it away.
 733          * The purpose of a sigreturn is to destroy all traces of the
 734          * signal frame, this includes any transactional state created
 735          * within in. We only check for suspended as we can never be
 736          * active in the kernel, we are active, there is nothing better to
 737          * do than go ahead and Bad Thing later.
 738          * The cause is not important as there will never be a
 739          * recheckpoint so it's not user visible.
 740          */
 741         if (MSR_TM_SUSPENDED(mfmsr()))
 742                 tm_reclaim_current(0);
 743
 744         /*
 745          * Disable MSR[TS] bit also, so, if there is an exception in the
 746          * code below (as a page fault in copy_ckvsx_to_user()), it does
 747          * not recheckpoint this task if there was a context switch inside
 748          * the exception.
 749          *
 750          * A major page fault can indirectly call schedule(). A reschedule
 751          * process in the middle of an exception can have a side effect
 752          * (Changing the CPU MSR[TS] state), since schedule() is called
 753          * with the CPU MSR[TS] disable and returns with MSR[TS]=Suspended
 754          * (switch_to() calls tm_recheckpoint() for the 'new' process). In
 755          * this case, the process continues to be the same in the CPU, but
 756          * the CPU state just changed.
 757          *
 758          * This can cause a TM Bad Thing, since the MSR in the stack will
 759          * have the MSR[TS]=0, and this is what will be used to RFID.
 760          *
 761          * Clearing MSR[TS] state here will avoid a recheckpoint if there
 762          * is any process reschedule in kernel space. The MSR[TS] state
 763          * does not need to be saved also, since it will be replaced with
 764          * the MSR[TS] that came from user context later, at
 765          * restore_tm_sigcontexts.
 766          */
 767         regs->msr &= ~MSR_TS_MASK;
 768
 769         if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR]))
 770                 goto badframe;
 771         if (MSR_TM_ACTIVE(msr)) {
 772                 /* We recheckpoint on return. */
 773                 struct ucontext __user *uc_transact;
 774
 775                 /* Trying to start TM on non TM system */
 776                 if (!cpu_has_feature(CPU_FTR_TM))
 777                         goto badframe;
 778
 779                 if (__get_user(uc_transact, &uc->uc_link))
 780                         goto badframe;
 781                 if (restore_tm_sigcontexts(current, &uc->uc_mcontext,
 782                                            &uc_transact->uc_mcontext))
 783                         goto badframe;
 784         } else
 785 #endif
 786         {
 787                 /*
 788                  * Fall through, for non-TM restore
 789                  *
 790                  * Unset MSR[TS] on the thread regs since MSR from user
 791                  * context does not have MSR active, and recheckpoint was
 792                  * not called since restore_tm_sigcontexts() was not called
 793                  * also.
 794                  *
 795                  * If not unsetting it, the code can RFID to userspace with
 796                  * MSR[TS] set, but without CPU in the proper state,
 797                  * causing a TM bad thing.
 798                  */
 799                 current->thread.regs->msr &= ~MSR_TS_MASK;
 800                 if (restore_sigcontext(current, NULL, 1, &uc->uc_mcontext))
 801                         goto badframe;
 802         }
 803
 804         if (restore_altstack(&uc->uc_stack))
 805                 goto badframe;
 806
 807         set_thread_flag(TIF_RESTOREALL);
 808         return 0;
 809
 810 badframe:
 811         if (show_unhandled_signals)
 812                 printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32,
 813                                    current->comm, current->pid, "rt_sigreturn",
 814                                    (long)uc, regs->nip, regs->link);
 815
 816         force_sig(SIGSEGV);
 817         return 0;
 818 }
 819
 820 int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
 821                 struct task_struct *tsk)
 822 {
 823         struct rt_sigframe __user *frame;
 824         unsigned long newsp = 0;
 825         long err = 0;
 826         struct pt_regs *regs = tsk->thread.regs;
 827
 828         BUG_ON(tsk != current);
 829
 830         frame = get_sigframe(ksig, get_tm_stackpointer(tsk), sizeof(*frame), 0);
 831         if (unlikely(frame == NULL))
 832                 goto badframe;
 833
 834         err |= __put_user(&frame->info, &frame->pinfo);
 835         err |= __put_user(&frame->uc, &frame->puc);
 836         err |= copy_siginfo_to_user(&frame->info, &ksig->info);
 837         if (err)
 838                 goto badframe;
 839
 840         /* Create the ucontext.  */
 841         err |= __put_user(0, &frame->uc.uc_flags);
 842         err |= __save_altstack(&frame->uc.uc_stack, regs->gpr[1]);
 843 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 844         if (MSR_TM_ACTIVE(regs->msr)) {
 845                 /* The ucontext_t passed to userland points to the second
 846                  * ucontext_t (for transactional state) with its uc_link ptr.
 847                  */
 848                 err |= __put_user(&frame->uc_transact, &frame->uc.uc_link);
 849                 err |= setup_tm_sigcontexts(&frame->uc.uc_mcontext,
 850                                             &frame->uc_transact.uc_mcontext,
 851                                             tsk, ksig->sig, NULL,
 852                                             (unsigned long)ksig->ka.sa.sa_handler);
 853         } else
 854 #endif
 855         {
 856                 err |= __put_user(0, &frame->uc.uc_link);
 857                 err |= setup_sigcontext(&frame->uc.uc_mcontext, tsk, ksig->sig,
 858                                         NULL, (unsigned long)ksig->ka.sa.sa_handler,
 859                                         1);
 860         }
 861         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 862         if (err)
 863                 goto badframe;
 864
 865         /* Make sure signal handler doesn't get spurious FP exceptions */
 866         tsk->thread.fp_state.fpscr = 0;
 867
 868         /* Set up to return from userspace. */
 869         if (vdso64_rt_sigtramp && tsk->mm->context.vdso_base) {
 870                 regs->link = tsk->mm->context.vdso_base + vdso64_rt_sigtramp;
 871         } else {
 872                 err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]);
 873                 if (err)
 874                         goto badframe;
 875                 regs->link = (unsigned long) &frame->tramp[0];
 876         }
 877
 878         /* Allocate a dummy caller frame for the signal handler. */
 879         newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE;
 880         err |= put_user(regs->gpr[1], (unsigned long __user *)newsp);
 881
 882         /* Set up "regs" so we "return" to the signal handler. */
 883         if (is_elf2_task()) {
 884                 regs->nip = (unsigned long) ksig->ka.sa.sa_handler;
 885                 regs->gpr[12] = regs->nip;
 886         } else {
 887                 /* Handler is *really* a pointer to the function descriptor for
 888                  * the signal routine.  The first entry in the function
 889                  * descriptor is the entry address of signal and the second
 890                  * entry is the TOC value we need to use.
 891                  */
 892                 func_descr_t __user *funct_desc_ptr =
 893                         (func_descr_t __user *) ksig->ka.sa.sa_handler;
 894
 895                 err |= get_user(regs->nip, &funct_desc_ptr->entry);
 896                 err |= get_user(regs->gpr[2], &funct_desc_ptr->toc);
 897         }
 898
 899         /* enter the signal handler in native-endian mode */
 900         regs->msr &= ~MSR_LE;
 901         regs->msr |= (MSR_KERNEL & MSR_LE);
 902         regs->gpr[1] = newsp;
 903         regs->gpr[3] = ksig->sig;
 904         regs->result = 0;
 905         if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
 906                 err |= get_user(regs->gpr[4], (unsigned long __user *)&frame->pinfo);
 907                 err |= get_user(regs->gpr[5], (unsigned long __user *)&frame->puc);
 908                 regs->gpr[6] = (unsigned long) frame;
 909         } else {
 910                 regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext;
 911         }
 912         if (err)
 913                 goto badframe;
 914
 915         return 0;
 916
 917 badframe:
 918         if (show_unhandled_signals)
 919                 printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32,
 920                                    tsk->comm, tsk->pid, "setup_rt_frame",
 921                                    (long)frame, regs->nip, regs->link);
 922
 923         return 1;
 924 }