root/arch/powerpc/kernel/signal_64.c

DEFINITIONS

1. sigcontext_vmx_regs
2. setup_sigcontext
3. setup_tm_sigcontexts
4. restore_sigcontext
5. restore_tm_sigcontexts
6. setup_trampoline
7. SYSCALL_DEFINE3
8. SYSCALL_DEFINE0
9. handle_rt_signal64

   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         /* Don't allow userspace to set the trap value */
 477         regs->trap = 0;
 478 
 479         /* These regs are not checkpointed; they can go in 'regs'. */
 480         err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]);
 481         err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]);
 482         err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]);
 483 
 484         /*
 485          * Force reload of FP/VEC.
 486          * This has to be done before copying stuff into tsk->thread.fpr/vr
 487          * for the reasons explained in the previous comment.
 488          */
 489         regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX);
 490 
 491 #ifdef CONFIG_ALTIVEC
 492         err |= __get_user(v_regs, &sc->v_regs);
 493         err |= __get_user(tm_v_regs, &tm_sc->v_regs);
 494         if (err)
 495                 return err;
 496         if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128)))
 497                 return -EFAULT;
 498         if (tm_v_regs && !access_ok(tm_v_regs, 34 * sizeof(vector128)))
 499                 return -EFAULT;
 500         /* Copy 33 vec registers (vr0..31 and vscr) from the stack */
 501         if (v_regs != NULL && tm_v_regs != NULL && (msr & MSR_VEC) != 0) {
 502                 err |= __copy_from_user(&tsk->thread.ckvr_state, v_regs,
 503                                         33 * sizeof(vector128));
 504                 err |= __copy_from_user(&tsk->thread.vr_state, tm_v_regs,
 505                                         33 * sizeof(vector128));
 506                 current->thread.used_vr = true;
 507         }
 508         else if (tsk->thread.used_vr) {
 509                 memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128));
 510                 memset(&tsk->thread.ckvr_state, 0, 33 * sizeof(vector128));
 511         }
 512         /* Always get VRSAVE back */
 513         if (v_regs != NULL && tm_v_regs != NULL) {
 514                 err |= __get_user(tsk->thread.ckvrsave,
 515                                   (u32 __user *)&v_regs[33]);
 516                 err |= __get_user(tsk->thread.vrsave,
 517                                   (u32 __user *)&tm_v_regs[33]);
 518         }
 519         else {
 520                 tsk->thread.vrsave = 0;
 521                 tsk->thread.ckvrsave = 0;
 522         }
 523         if (cpu_has_feature(CPU_FTR_ALTIVEC))
 524                 mtspr(SPRN_VRSAVE, tsk->thread.vrsave);
 525 #endif /* CONFIG_ALTIVEC */
 526         /* restore floating point */
 527         err |= copy_fpr_from_user(tsk, &tm_sc->fp_regs);
 528         err |= copy_ckfpr_from_user(tsk, &sc->fp_regs);
 529 #ifdef CONFIG_VSX
 530         /*
 531          * Get additional VSX data. Update v_regs to point after the
 532          * VMX data.  Copy VSX low doubleword from userspace to local
 533          * buffer for formatting, then into the taskstruct.
 534          */
 535         if (v_regs && ((msr & MSR_VSX) != 0)) {
 536                 v_regs += ELF_NVRREG;
 537                 tm_v_regs += ELF_NVRREG;
 538                 err |= copy_vsx_from_user(tsk, tm_v_regs);
 539                 err |= copy_ckvsx_from_user(tsk, v_regs);
 540                 tsk->thread.used_vsr = true;
 541         } else {
 542                 for (i = 0; i < 32 ; i++) {
 543                         tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
 544                         tsk->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
 545                 }
 546         }
 547 #endif
 548         tm_enable();
 549         /* Make sure the transaction is marked as failed */
 550         tsk->thread.tm_texasr |= TEXASR_FS;
 551 
 552         /*
 553          * Disabling preemption, since it is unsafe to be preempted
 554          * with MSR[TS] set without recheckpointing.
 555          */
 556         preempt_disable();
 557 
 558         /* pull in MSR TS bits from user context */
 559         regs->msr |= msr & MSR_TS_MASK;
 560 
 561         /*
 562          * Ensure that TM is enabled in regs->msr before we leave the signal
 563          * handler. It could be the case that (a) user disabled the TM bit
 564          * through the manipulation of the MSR bits in uc_mcontext or (b) the
 565          * TM bit was disabled because a sufficient number of context switches
 566          * happened whilst in the signal handler and load_tm overflowed,
 567          * disabling the TM bit. In either case we can end up with an illegal
 568          * TM state leading to a TM Bad Thing when we return to userspace.
 569          *
 570          * CAUTION:
 571          * After regs->MSR[TS] being updated, make sure that get_user(),
 572          * put_user() or similar functions are *not* called. These
 573          * functions can generate page faults which will cause the process
 574          * to be de-scheduled with MSR[TS] set but without calling
 575          * tm_recheckpoint(). This can cause a bug.
 576          */
 577         regs->msr |= MSR_TM;
 578 
 579         /* This loads the checkpointed FP/VEC state, if used */
 580         tm_recheckpoint(&tsk->thread);
 581 
 582         msr_check_and_set(msr & (MSR_FP | MSR_VEC));
 583         if (msr & MSR_FP) {
 584                 load_fp_state(&tsk->thread.fp_state);
 585                 regs->msr |= (MSR_FP | tsk->thread.fpexc_mode);
 586         }
 587         if (msr & MSR_VEC) {
 588                 load_vr_state(&tsk->thread.vr_state);
 589                 regs->msr |= MSR_VEC;
 590         }
 591 
 592         preempt_enable();
 593 
 594         return err;
 595 }
 596 #endif
 597 
 598 /*
 599  * Setup the trampoline code on the stack
 600  */
 601 static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp)
 602 {
 603         int i;
 604         long err = 0;
 605 
 606         /* addi r1, r1, __SIGNAL_FRAMESIZE  # Pop the dummy stackframe */
 607         err |= __put_user(PPC_INST_ADDI | __PPC_RT(R1) | __PPC_RA(R1) |
 608                           (__SIGNAL_FRAMESIZE & 0xffff), &tramp[0]);
 609         /* li r0, __NR_[rt_]sigreturn| */
 610         err |= __put_user(PPC_INST_ADDI | (syscall & 0xffff), &tramp[1]);
 611         /* sc */
 612         err |= __put_user(PPC_INST_SC, &tramp[2]);
 613 
 614         /* Minimal traceback info */
 615         for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++)
 616                 err |= __put_user(0, &tramp[i]);
 617 
 618         if (!err)
 619                 flush_icache_range((unsigned long) &tramp[0],
 620                            (unsigned long) &tramp[TRAMP_SIZE]);
 621 
 622         return err;
 623 }
 624 
 625 /*
 626  * Userspace code may pass a ucontext which doesn't include VSX added
 627  * at the end.  We need to check for this case.
 628  */
 629 #define UCONTEXTSIZEWITHOUTVSX \
 630                 (sizeof(struct ucontext) - 32*sizeof(long))
 631 
 632 /*
 633  * Handle {get,set,swap}_context operations
 634  */
 635 SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx,
 636                 struct ucontext __user *, new_ctx, long, ctx_size)
 637 {
 638         unsigned char tmp;
 639         sigset_t set;
 640         unsigned long new_msr = 0;
 641         int ctx_has_vsx_region = 0;
 642 
 643         if (new_ctx &&
 644             get_user(new_msr, &new_ctx->uc_mcontext.gp_regs[PT_MSR]))
 645                 return -EFAULT;
 646         /*
 647          * Check that the context is not smaller than the original
 648          * size (with VMX but without VSX)
 649          */
 650         if (ctx_size < UCONTEXTSIZEWITHOUTVSX)
 651                 return -EINVAL;
 652         /*
 653          * If the new context state sets the MSR VSX bits but
 654          * it doesn't provide VSX state.
 655          */
 656         if ((ctx_size < sizeof(struct ucontext)) &&
 657             (new_msr & MSR_VSX))
 658                 return -EINVAL;
 659         /* Does the context have enough room to store VSX data? */
 660         if (ctx_size >= sizeof(struct ucontext))
 661                 ctx_has_vsx_region = 1;
 662 
 663         if (old_ctx != NULL) {
 664                 if (!access_ok(old_ctx, ctx_size)
 665                     || setup_sigcontext(&old_ctx->uc_mcontext, current, 0, NULL, 0,
 666                                         ctx_has_vsx_region)
 667                     || __copy_to_user(&old_ctx->uc_sigmask,
 668                                       &current->blocked, sizeof(sigset_t)))
 669                         return -EFAULT;
 670         }
 671         if (new_ctx == NULL)
 672                 return 0;
 673         if (!access_ok(new_ctx, ctx_size)
 674             || __get_user(tmp, (u8 __user *) new_ctx)
 675             || __get_user(tmp, (u8 __user *) new_ctx + ctx_size - 1))
 676                 return -EFAULT;
 677 
 678         /*
 679          * If we get a fault copying the context into the kernel's
 680          * image of the user's registers, we can't just return -EFAULT
 681          * because the user's registers will be corrupted.  For instance
 682          * the NIP value may have been updated but not some of the
 683          * other registers.  Given that we have done the access_ok
 684          * and successfully read the first and last bytes of the region
 685          * above, this should only happen in an out-of-memory situation
 686          * or if another thread unmaps the region containing the context.
 687          * We kill the task with a SIGSEGV in this situation.
 688          */
 689 
 690         if (__copy_from_user(&set, &new_ctx->uc_sigmask, sizeof(set)))
 691                 do_exit(SIGSEGV);
 692         set_current_blocked(&set);
 693         if (restore_sigcontext(current, NULL, 0, &new_ctx->uc_mcontext))
 694                 do_exit(SIGSEGV);
 695 
 696         /* This returns like rt_sigreturn */
 697         set_thread_flag(TIF_RESTOREALL);
 698         return 0;
 699 }
 700 
 701 
 702 /*
 703  * Do a signal return; undo the signal stack.
 704  */
 705 
 706 SYSCALL_DEFINE0(rt_sigreturn)
 707 {
 708         struct pt_regs *regs = current_pt_regs();
 709         struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1];
 710         sigset_t set;
 711 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 712         unsigned long msr;
 713 #endif
 714 
 715         /* Always make any pending restarted system calls return -EINTR */
 716         current->restart_block.fn = do_no_restart_syscall;
 717 
 718         if (!access_ok(uc, sizeof(*uc)))
 719                 goto badframe;
 720 
 721         if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
 722                 goto badframe;
 723         set_current_blocked(&set);
 724 
 725 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 726         /*
 727          * If there is a transactional state then throw it away.
 728          * The purpose of a sigreturn is to destroy all traces of the
 729          * signal frame, this includes any transactional state created
 730          * within in. We only check for suspended as we can never be
 731          * active in the kernel, we are active, there is nothing better to
 732          * do than go ahead and Bad Thing later.
 733          * The cause is not important as there will never be a
 734          * recheckpoint so it's not user visible.
 735          */
 736         if (MSR_TM_SUSPENDED(mfmsr()))
 737                 tm_reclaim_current(0);
 738 
 739         /*
 740          * Disable MSR[TS] bit also, so, if there is an exception in the
 741          * code below (as a page fault in copy_ckvsx_to_user()), it does
 742          * not recheckpoint this task if there was a context switch inside
 743          * the exception.
 744          *
 745          * A major page fault can indirectly call schedule(). A reschedule
 746          * process in the middle of an exception can have a side effect
 747          * (Changing the CPU MSR[TS] state), since schedule() is called
 748          * with the CPU MSR[TS] disable and returns with MSR[TS]=Suspended
 749          * (switch_to() calls tm_recheckpoint() for the 'new' process). In
 750          * this case, the process continues to be the same in the CPU, but
 751          * the CPU state just changed.
 752          *
 753          * This can cause a TM Bad Thing, since the MSR in the stack will
 754          * have the MSR[TS]=0, and this is what will be used to RFID.
 755          *
 756          * Clearing MSR[TS] state here will avoid a recheckpoint if there
 757          * is any process reschedule in kernel space. The MSR[TS] state
 758          * does not need to be saved also, since it will be replaced with
 759          * the MSR[TS] that came from user context later, at
 760          * restore_tm_sigcontexts.
 761          */
 762         regs->msr &= ~MSR_TS_MASK;
 763 
 764         if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR]))
 765                 goto badframe;
 766         if (MSR_TM_ACTIVE(msr)) {
 767                 /* We recheckpoint on return. */
 768                 struct ucontext __user *uc_transact;
 769 
 770                 /* Trying to start TM on non TM system */
 771                 if (!cpu_has_feature(CPU_FTR_TM))
 772                         goto badframe;
 773 
 774                 if (__get_user(uc_transact, &uc->uc_link))
 775                         goto badframe;
 776                 if (restore_tm_sigcontexts(current, &uc->uc_mcontext,
 777                                            &uc_transact->uc_mcontext))
 778                         goto badframe;
 779         } else
 780 #endif
 781         {
 782                 /*
 783                  * Fall through, for non-TM restore
 784                  *
 785                  * Unset MSR[TS] on the thread regs since MSR from user
 786                  * context does not have MSR active, and recheckpoint was
 787                  * not called since restore_tm_sigcontexts() was not called
 788                  * also.
 789                  *
 790                  * If not unsetting it, the code can RFID to userspace with
 791                  * MSR[TS] set, but without CPU in the proper state,
 792                  * causing a TM bad thing.
 793                  */
 794                 current->thread.regs->msr &= ~MSR_TS_MASK;
 795                 if (restore_sigcontext(current, NULL, 1, &uc->uc_mcontext))
 796                         goto badframe;
 797         }
 798 
 799         if (restore_altstack(&uc->uc_stack))
 800                 goto badframe;
 801 
 802         set_thread_flag(TIF_RESTOREALL);
 803         return 0;
 804 
 805 badframe:
 806         if (show_unhandled_signals)
 807                 printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32,
 808                                    current->comm, current->pid, "rt_sigreturn",
 809                                    (long)uc, regs->nip, regs->link);
 810 
 811         force_sig(SIGSEGV);
 812         return 0;
 813 }
 814 
 815 int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
 816                 struct task_struct *tsk)
 817 {
 818         struct rt_sigframe __user *frame;
 819         unsigned long newsp = 0;
 820         long err = 0;
 821         struct pt_regs *regs = tsk->thread.regs;
 822 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 823         /* Save the thread's msr before get_tm_stackpointer() changes it */
 824         unsigned long msr = regs->msr;
 825 #endif
 826 
 827         BUG_ON(tsk != current);
 828 
 829         frame = get_sigframe(ksig, get_tm_stackpointer(tsk), sizeof(*frame), 0);
 830         if (unlikely(frame == NULL))
 831                 goto badframe;
 832 
 833         err |= __put_user(&frame->info, &frame->pinfo);
 834         err |= __put_user(&frame->uc, &frame->puc);
 835         err |= copy_siginfo_to_user(&frame->info, &ksig->info);
 836         if (err)
 837                 goto badframe;
 838 
 839         /* Create the ucontext.  */
 840         err |= __put_user(0, &frame->uc.uc_flags);
 841         err |= __save_altstack(&frame->uc.uc_stack, regs->gpr[1]);
 842 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 843         if (MSR_TM_ACTIVE(msr)) {
 844                 /* The ucontext_t passed to userland points to the second
 845                  * ucontext_t (for transactional state) with its uc_link ptr.
 846                  */
 847                 err |= __put_user(&frame->uc_transact, &frame->uc.uc_link);
 848                 err |= setup_tm_sigcontexts(&frame->uc.uc_mcontext,
 849                                             &frame->uc_transact.uc_mcontext,
 850                                             tsk, ksig->sig, NULL,
 851                                             (unsigned long)ksig->ka.sa.sa_handler,
 852                                             msr);
 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 }