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 #include <linux/pagemap.h>
  25
  26 #include <asm/sigcontext.h>
  27 #include <asm/ucontext.h>
  28 #include <linux/uaccess.h>
  29 #include <asm/unistd.h>
  30 #include <asm/cacheflush.h>
  31 #include <asm/syscalls.h>
  32 #include <asm/vdso.h>
  33 #include <asm/switch_to.h>
  34 #include <asm/tm.h>
  35 #include <asm/asm-prototypes.h>
  36
  37 #include "signal.h"
  38
  39
  40 #define GP_REGS_SIZE    min(sizeof(elf_gregset_t), sizeof(struct pt_regs))
  41 #define FP_REGS_SIZE    sizeof(elf_fpregset_t)
  42
  43 #define TRAMP_TRACEBACK 4
  44 #define TRAMP_SIZE      7
  45
  46 /*
  47  * When we have signals to deliver, we set up on the user stack,
  48  * going down from the original stack pointer:
  49  *      1) a rt_sigframe struct which contains the ucontext
  50  *      2) a gap of __SIGNAL_FRAMESIZE bytes which acts as a dummy caller
  51  *         frame for the signal handler.
  52  */
  53
  54 struct rt_sigframe {
  55         /* sys_rt_sigreturn requires the ucontext be the first field */
  56         struct ucontext uc;
  57 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
  58         struct ucontext uc_transact;
  59 #endif
  60         unsigned long _unused[2];
  61         unsigned int tramp[TRAMP_SIZE];
  62         struct siginfo __user *pinfo;
  63         void __user *puc;
  64         struct siginfo info;
  65         /* New 64 bit little-endian ABI allows redzone of 512 bytes below sp */
  66         char abigap[USER_REDZONE_SIZE];
  67 } __attribute__ ((aligned (16)));
  68
  69 /*
  70  * This computes a quad word aligned pointer inside the vmx_reserve array
  71  * element. For historical reasons sigcontext might not be quad word aligned,
  72  * but the location we write the VMX regs to must be. See the comment in
  73  * sigcontext for more detail.
  74  */
  75 #ifdef CONFIG_ALTIVEC
  76 static elf_vrreg_t __user *sigcontext_vmx_regs(struct sigcontext __user *sc)
  77 {
  78         return (elf_vrreg_t __user *) (((unsigned long)sc->vmx_reserve + 15) & ~0xful);
  79 }
  80 #endif
  81
  82 /*
  83  * Set up the sigcontext for the signal frame.
  84  */
  85
  86 static long setup_sigcontext(struct sigcontext __user *sc,
  87                 struct task_struct *tsk, int signr, sigset_t *set,
  88                 unsigned long handler, int ctx_has_vsx_region)
  89 {
  90         /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the
  91          * process never used altivec yet (MSR_VEC is zero in pt_regs of
  92          * the context). This is very important because we must ensure we
  93          * don't lose the VRSAVE content that may have been set prior to
  94          * the process doing its first vector operation
  95          * Userland shall check AT_HWCAP to know whether it can rely on the
  96          * v_regs pointer or not
  97          */
  98 #ifdef CONFIG_ALTIVEC
  99         elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc);
 100         unsigned long vrsave;
 101 #endif
 102         struct pt_regs *regs = tsk->thread.regs;
 103         unsigned long msr = regs->msr;
 104         long err = 0;
 105         /* Force usr to alway see softe as 1 (interrupts enabled) */
 106         unsigned long softe = 0x1;
 107
 108         BUG_ON(tsk != current);
 109
 110 #ifdef CONFIG_ALTIVEC
 111         err |= __put_user(v_regs, &sc->v_regs);
 112
 113         /* save altivec registers */
 114         if (tsk->thread.used_vr) {
 115                 flush_altivec_to_thread(tsk);
 116                 /* Copy 33 vec registers (vr0..31 and vscr) to the stack */
 117                 err |= __copy_to_user(v_regs, &tsk->thread.vr_state,
 118                                       33 * sizeof(vector128));
 119                 /* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg)
 120                  * contains valid data.
 121                  */
 122                 msr |= MSR_VEC;
 123         }
 124         /* We always copy to/from vrsave, it's 0 if we don't have or don't
 125          * use altivec.
 126          */
 127         vrsave = 0;
 128         if (cpu_has_feature(CPU_FTR_ALTIVEC)) {
 129                 vrsave = mfspr(SPRN_VRSAVE);
 130                 tsk->thread.vrsave = vrsave;
 131         }
 132
 133         err |= __put_user(vrsave, (u32 __user *)&v_regs[33]);
 134 #else /* CONFIG_ALTIVEC */
 135         err |= __put_user(0, &sc->v_regs);
 136 #endif /* CONFIG_ALTIVEC */
 137         flush_fp_to_thread(tsk);
 138         /* copy fpr regs and fpscr */
 139         err |= copy_fpr_to_user(&sc->fp_regs, tsk);
 140
 141         /*
 142          * Clear the MSR VSX bit to indicate there is no valid state attached
 143          * to this context, except in the specific case below where we set it.
 144          */
 145         msr &= ~MSR_VSX;
 146 #ifdef CONFIG_VSX
 147         /*
 148          * Copy VSX low doubleword to local buffer for formatting,
 149          * then out to userspace.  Update v_regs to point after the
 150          * VMX data.
 151          */
 152         if (tsk->thread.used_vsr && ctx_has_vsx_region) {
 153                 flush_vsx_to_thread(tsk);
 154                 v_regs += ELF_NVRREG;
 155                 err |= copy_vsx_to_user(v_regs, tsk);
 156                 /* set MSR_VSX in the MSR value in the frame to
 157                  * indicate that sc->vs_reg) contains valid data.
 158                  */
 159                 msr |= MSR_VSX;
 160         }
 161 #endif /* CONFIG_VSX */
 162         err |= __put_user(&sc->gp_regs, &sc->regs);
 163         WARN_ON(!FULL_REGS(regs));
 164         err |= __copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE);
 165         err |= __put_user(msr, &sc->gp_regs[PT_MSR]);
 166         err |= __put_user(softe, &sc->gp_regs[PT_SOFTE]);
 167         err |= __put_user(signr, &sc->signal);
 168         err |= __put_user(handler, &sc->handler);
 169         if (set != NULL)
 170                 err |=  __put_user(set->sig[0], &sc->oldmask);
 171
 172         return err;
 173 }
 174
 175 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 176 /*
 177  * As above, but Transactional Memory is in use, so deliver sigcontexts
 178  * containing checkpointed and transactional register states.
 179  *
 180  * To do this, we treclaim (done before entering here) to gather both sets of
 181  * registers and set up the 'normal' sigcontext registers with rolled-back
 182  * register values such that a simple signal handler sees a correct
 183  * checkpointed register state.  If interested, a TM-aware sighandler can
 184  * examine the transactional registers in the 2nd sigcontext to determine the
 185  * real origin of the signal.
 186  */
 187 static long setup_tm_sigcontexts(struct sigcontext __user *sc,
 188                                  struct sigcontext __user *tm_sc,
 189                                  struct task_struct *tsk,
 190                                  int signr, sigset_t *set, unsigned long handler,
 191                                  unsigned long msr)
 192 {
 193         /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the
 194          * process never used altivec yet (MSR_VEC is zero in pt_regs of
 195          * the context). This is very important because we must ensure we
 196          * don't lose the VRSAVE content that may have been set prior to
 197          * the process doing its first vector operation
 198          * Userland shall check AT_HWCAP to know wether it can rely on the
 199          * v_regs pointer or not.
 200          */
 201 #ifdef CONFIG_ALTIVEC
 202         elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc);
 203         elf_vrreg_t __user *tm_v_regs = sigcontext_vmx_regs(tm_sc);
 204 #endif
 205         struct pt_regs *regs = tsk->thread.regs;
 206         long err = 0;
 207
 208         BUG_ON(tsk != current);
 209
 210         BUG_ON(!MSR_TM_ACTIVE(msr));
 211
 212         WARN_ON(tm_suspend_disabled);
 213
 214         /* Restore checkpointed FP, VEC, and VSX bits from ckpt_regs as
 215          * it contains the correct FP, VEC, VSX state after we treclaimed
 216          * the transaction and giveup_all() was called on reclaiming.
 217          */
 218         msr |= tsk->thread.ckpt_regs.msr & (MSR_FP | MSR_VEC | MSR_VSX);
 219
 220 #ifdef CONFIG_ALTIVEC
 221         err |= __put_user(v_regs, &sc->v_regs);
 222         err |= __put_user(tm_v_regs, &tm_sc->v_regs);
 223
 224         /* save altivec registers */
 225         if (tsk->thread.used_vr) {
 226                 /* Copy 33 vec registers (vr0..31 and vscr) to the stack */
 227                 err |= __copy_to_user(v_regs, &tsk->thread.ckvr_state,
 228                                       33 * sizeof(vector128));
 229                 /* If VEC was enabled there are transactional VRs valid too,
 230                  * else they're a copy of the checkpointed VRs.
 231                  */
 232                 if (msr & MSR_VEC)
 233                         err |= __copy_to_user(tm_v_regs,
 234                                               &tsk->thread.vr_state,
 235                                               33 * sizeof(vector128));
 236                 else
 237                         err |= __copy_to_user(tm_v_regs,
 238                                               &tsk->thread.ckvr_state,
 239                                               33 * sizeof(vector128));
 240
 241                 /* set MSR_VEC in the MSR value in the frame to indicate
 242                  * that sc->v_reg contains valid data.
 243                  */
 244                 msr |= MSR_VEC;
 245         }
 246         /* We always copy to/from vrsave, it's 0 if we don't have or don't
 247          * use altivec.
 248          */
 249         if (cpu_has_feature(CPU_FTR_ALTIVEC))
 250                 tsk->thread.ckvrsave = mfspr(SPRN_VRSAVE);
 251         err |= __put_user(tsk->thread.ckvrsave, (u32 __user *)&v_regs[33]);
 252         if (msr & MSR_VEC)
 253                 err |= __put_user(tsk->thread.vrsave,
 254                                   (u32 __user *)&tm_v_regs[33]);
 255         else
 256                 err |= __put_user(tsk->thread.ckvrsave,
 257                                   (u32 __user *)&tm_v_regs[33]);
 258
 259 #else /* CONFIG_ALTIVEC */
 260         err |= __put_user(0, &sc->v_regs);
 261         err |= __put_user(0, &tm_sc->v_regs);
 262 #endif /* CONFIG_ALTIVEC */
 263
 264         /* copy fpr regs and fpscr */
 265         err |= copy_ckfpr_to_user(&sc->fp_regs, tsk);
 266         if (msr & MSR_FP)
 267                 err |= copy_fpr_to_user(&tm_sc->fp_regs, tsk);
 268         else
 269                 err |= copy_ckfpr_to_user(&tm_sc->fp_regs, tsk);
 270
 271 #ifdef CONFIG_VSX
 272         /*
 273          * Copy VSX low doubleword to local buffer for formatting,
 274          * then out to userspace.  Update v_regs to point after the
 275          * VMX data.
 276          */
 277         if (tsk->thread.used_vsr) {
 278                 v_regs += ELF_NVRREG;
 279                 tm_v_regs += ELF_NVRREG;
 280
 281                 err |= copy_ckvsx_to_user(v_regs, tsk);
 282
 283                 if (msr & MSR_VSX)
 284                         err |= copy_vsx_to_user(tm_v_regs, tsk);
 285                 else
 286                         err |= copy_ckvsx_to_user(tm_v_regs, tsk);
 287
 288                 /* set MSR_VSX in the MSR value in the frame to
 289                  * indicate that sc->vs_reg) contains valid data.
 290                  */
 291                 msr |= MSR_VSX;
 292         }
 293 #endif /* CONFIG_VSX */
 294
 295         err |= __put_user(&sc->gp_regs, &sc->regs);
 296         err |= __put_user(&tm_sc->gp_regs, &tm_sc->regs);
 297         WARN_ON(!FULL_REGS(regs));
 298         err |= __copy_to_user(&tm_sc->gp_regs, regs, GP_REGS_SIZE);
 299         err |= __copy_to_user(&sc->gp_regs,
 300                               &tsk->thread.ckpt_regs, GP_REGS_SIZE);
 301         err |= __put_user(msr, &tm_sc->gp_regs[PT_MSR]);
 302         err |= __put_user(msr, &sc->gp_regs[PT_MSR]);
 303         err |= __put_user(signr, &sc->signal);
 304         err |= __put_user(handler, &sc->handler);
 305         if (set != NULL)
 306                 err |=  __put_user(set->sig[0], &sc->oldmask);
 307
 308         return err;
 309 }
 310 #endif
 311
 312 /*
 313  * Restore the sigcontext from the signal frame.
 314  */
 315
 316 static long restore_sigcontext(struct task_struct *tsk, sigset_t *set, int sig,
 317                               struct sigcontext __user *sc)
 318 {
 319 #ifdef CONFIG_ALTIVEC
 320         elf_vrreg_t __user *v_regs;
 321 #endif
 322         unsigned long err = 0;
 323         unsigned long save_r13 = 0;
 324         unsigned long msr;
 325         struct pt_regs *regs = tsk->thread.regs;
 326 #ifdef CONFIG_VSX
 327         int i;
 328 #endif
 329
 330         BUG_ON(tsk != current);
 331
 332         /* If this is not a signal return, we preserve the TLS in r13 */
 333         if (!sig)
 334                 save_r13 = regs->gpr[13];
 335
 336         /* copy the GPRs */
 337         err |= __copy_from_user(regs->gpr, sc->gp_regs, sizeof(regs->gpr));
 338         err |= __get_user(regs->nip, &sc->gp_regs[PT_NIP]);
 339         /* get MSR separately, transfer the LE bit if doing signal return */
 340         err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
 341         if (sig)
 342                 regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);
 343         err |= __get_user(regs->orig_gpr3, &sc->gp_regs[PT_ORIG_R3]);
 344         err |= __get_user(regs->ctr, &sc->gp_regs[PT_CTR]);
 345         err |= __get_user(regs->link, &sc->gp_regs[PT_LNK]);
 346         err |= __get_user(regs->xer, &sc->gp_regs[PT_XER]);
 347         err |= __get_user(regs->ccr, &sc->gp_regs[PT_CCR]);
 348         /* Don't allow userspace to set SOFTE */
 349         set_trap_norestart(regs);
 350         err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]);
 351         err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]);
 352         err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]);
 353
 354         if (!sig)
 355                 regs->gpr[13] = save_r13;
 356         if (set != NULL)
 357                 err |=  __get_user(set->sig[0], &sc->oldmask);
 358
 359         /*
 360          * Force reload of FP/VEC.
 361          * This has to be done before copying stuff into tsk->thread.fpr/vr
 362          * for the reasons explained in the previous comment.
 363          */
 364         regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX);
 365
 366 #ifdef CONFIG_ALTIVEC
 367         err |= __get_user(v_regs, &sc->v_regs);
 368         if (err)
 369                 return err;
 370         if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128)))
 371                 return -EFAULT;
 372         /* Copy 33 vec registers (vr0..31 and vscr) from the stack */
 373         if (v_regs != NULL && (msr & MSR_VEC) != 0) {
 374                 err |= __copy_from_user(&tsk->thread.vr_state, v_regs,
 375                                         33 * sizeof(vector128));
 376                 tsk->thread.used_vr = true;
 377         } else if (tsk->thread.used_vr) {
 378                 memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128));
 379         }
 380         /* Always get VRSAVE back */
 381         if (v_regs != NULL)
 382                 err |= __get_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33]);
 383         else
 384                 tsk->thread.vrsave = 0;
 385         if (cpu_has_feature(CPU_FTR_ALTIVEC))
 386                 mtspr(SPRN_VRSAVE, tsk->thread.vrsave);
 387 #endif /* CONFIG_ALTIVEC */
 388         /* restore floating point */
 389         err |= copy_fpr_from_user(tsk, &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(tsk, v_regs);
 399                 tsk->thread.used_vsr = true;
 400         } else {
 401                 for (i = 0; i < 32 ; i++)
 402                         tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
 403         }
 404 #endif
 405         return err;
 406 }
 407
 408 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 409 /*
 410  * Restore the two sigcontexts from the frame of a transactional processes.
 411  */
 412
 413 static long restore_tm_sigcontexts(struct task_struct *tsk,
 414                                    struct sigcontext __user *sc,
 415                                    struct sigcontext __user *tm_sc)
 416 {
 417 #ifdef CONFIG_ALTIVEC
 418         elf_vrreg_t __user *v_regs, *tm_v_regs;
 419 #endif
 420         unsigned long err = 0;
 421         unsigned long msr;
 422         struct pt_regs *regs = tsk->thread.regs;
 423 #ifdef CONFIG_VSX
 424         int i;
 425 #endif
 426
 427         BUG_ON(tsk != current);
 428
 429         if (tm_suspend_disabled)
 430                 return -EINVAL;
 431
 432         /* copy the GPRs */
 433         err |= __copy_from_user(regs->gpr, tm_sc->gp_regs, sizeof(regs->gpr));
 434         err |= __copy_from_user(&tsk->thread.ckpt_regs, sc->gp_regs,
 435                                 sizeof(regs->gpr));
 436
 437         /*
 438          * TFHAR is restored from the checkpointed 'wound-back' ucontext's NIP.
 439          * TEXASR was set by the signal delivery reclaim, as was TFIAR.
 440          * Users doing anything abhorrent like thread-switching w/ signals for
 441          * TM-Suspended code will have to back TEXASR/TFIAR up themselves.
 442          * For the case of getting a signal and simply returning from it,
 443          * we don't need to re-copy them here.
 444          */
 445         err |= __get_user(regs->nip, &tm_sc->gp_regs[PT_NIP]);
 446         err |= __get_user(tsk->thread.tm_tfhar, &sc->gp_regs[PT_NIP]);
 447
 448         /* get MSR separately, transfer the LE bit if doing signal return */
 449         err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
 450         /* Don't allow reserved mode. */
 451         if (MSR_TM_RESV(msr))
 452                 return -EINVAL;
 453
 454         /* pull in MSR LE from user context */
 455         regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);
 456
 457         /* The following non-GPR non-FPR non-VR state is also checkpointed: */
 458         err |= __get_user(regs->ctr, &tm_sc->gp_regs[PT_CTR]);
 459         err |= __get_user(regs->link, &tm_sc->gp_regs[PT_LNK]);
 460         err |= __get_user(regs->xer, &tm_sc->gp_regs[PT_XER]);
 461         err |= __get_user(regs->ccr, &tm_sc->gp_regs[PT_CCR]);
 462         err |= __get_user(tsk->thread.ckpt_regs.ctr,
 463                           &sc->gp_regs[PT_CTR]);
 464         err |= __get_user(tsk->thread.ckpt_regs.link,
 465                           &sc->gp_regs[PT_LNK]);
 466         err |= __get_user(tsk->thread.ckpt_regs.xer,
 467                           &sc->gp_regs[PT_XER]);
 468         err |= __get_user(tsk->thread.ckpt_regs.ccr,
 469                           &sc->gp_regs[PT_CCR]);
 470         /* Don't allow userspace to set SOFTE */
 471         set_trap_norestart(regs);
 472         /* These regs are not checkpointed; they can go in 'regs'. */
 473         err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]);
 474         err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]);
 475         err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]);
 476
 477         /*
 478          * Force reload of FP/VEC.
 479          * This has to be done before copying stuff into tsk->thread.fpr/vr
 480          * for the reasons explained in the previous comment.
 481          */
 482         regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX);
 483
 484 #ifdef CONFIG_ALTIVEC
 485         err |= __get_user(v_regs, &sc->v_regs);
 486         err |= __get_user(tm_v_regs, &tm_sc->v_regs);
 487         if (err)
 488                 return err;
 489         if (v_regs && !access_ok(v_regs, 34 * sizeof(vector128)))
 490                 return -EFAULT;
 491         if (tm_v_regs && !access_ok(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(&tsk->thread.ckvr_state, v_regs,
 496                                         33 * sizeof(vector128));
 497                 err |= __copy_from_user(&tsk->thread.vr_state, tm_v_regs,
 498                                         33 * sizeof(vector128));
 499                 current->thread.used_vr = true;
 500         }
 501         else if (tsk->thread.used_vr) {
 502                 memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128));
 503                 memset(&tsk->thread.ckvr_state, 0, 33 * sizeof(vector128));
 504         }
 505         /* Always get VRSAVE back */
 506         if (v_regs != NULL && tm_v_regs != NULL) {
 507                 err |= __get_user(tsk->thread.ckvrsave,
 508                                   (u32 __user *)&v_regs[33]);
 509                 err |= __get_user(tsk->thread.vrsave,
 510                                   (u32 __user *)&tm_v_regs[33]);
 511         }
 512         else {
 513                 tsk->thread.vrsave = 0;
 514                 tsk->thread.ckvrsave = 0;
 515         }
 516         if (cpu_has_feature(CPU_FTR_ALTIVEC))
 517                 mtspr(SPRN_VRSAVE, tsk->thread.vrsave);
 518 #endif /* CONFIG_ALTIVEC */
 519         /* restore floating point */
 520         err |= copy_fpr_from_user(tsk, &tm_sc->fp_regs);
 521         err |= copy_ckfpr_from_user(tsk, &sc->fp_regs);
 522 #ifdef CONFIG_VSX
 523         /*
 524          * Get additional VSX data. Update v_regs to point after the
 525          * VMX data.  Copy VSX low doubleword from userspace to local
 526          * buffer for formatting, then into the taskstruct.
 527          */
 528         if (v_regs && ((msr & MSR_VSX) != 0)) {
 529                 v_regs += ELF_NVRREG;
 530                 tm_v_regs += ELF_NVRREG;
 531                 err |= copy_vsx_from_user(tsk, tm_v_regs);
 532                 err |= copy_ckvsx_from_user(tsk, v_regs);
 533                 tsk->thread.used_vsr = true;
 534         } else {
 535                 for (i = 0; i < 32 ; i++) {
 536                         tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
 537                         tsk->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
 538                 }
 539         }
 540 #endif
 541         tm_enable();
 542         /* Make sure the transaction is marked as failed */
 543         tsk->thread.tm_texasr |= TEXASR_FS;
 544
 545         /*
 546          * Disabling preemption, since it is unsafe to be preempted
 547          * with MSR[TS] set without recheckpointing.
 548          */
 549         preempt_disable();
 550
 551         /* pull in MSR TS bits from user context */
 552         regs->msr |= msr & MSR_TS_MASK;
 553
 554         /*
 555          * Ensure that TM is enabled in regs->msr before we leave the signal
 556          * handler. It could be the case that (a) user disabled the TM bit
 557          * through the manipulation of the MSR bits in uc_mcontext or (b) the
 558          * TM bit was disabled because a sufficient number of context switches
 559          * happened whilst in the signal handler and load_tm overflowed,
 560          * disabling the TM bit. In either case we can end up with an illegal
 561          * TM state leading to a TM Bad Thing when we return to userspace.
 562          *
 563          * CAUTION:
 564          * After regs->MSR[TS] being updated, make sure that get_user(),
 565          * put_user() or similar functions are *not* called. These
 566          * functions can generate page faults which will cause the process
 567          * to be de-scheduled with MSR[TS] set but without calling
 568          * tm_recheckpoint(). This can cause a bug.
 569          */
 570         regs->msr |= MSR_TM;
 571
 572         /* This loads the checkpointed FP/VEC state, if used */
 573         tm_recheckpoint(&tsk->thread);
 574
 575         msr_check_and_set(msr & (MSR_FP | MSR_VEC));
 576         if (msr & MSR_FP) {
 577                 load_fp_state(&tsk->thread.fp_state);
 578                 regs->msr |= (MSR_FP | tsk->thread.fpexc_mode);
 579         }
 580         if (msr & MSR_VEC) {
 581                 load_vr_state(&tsk->thread.vr_state);
 582                 regs->msr |= MSR_VEC;
 583         }
 584
 585         preempt_enable();
 586
 587         return err;
 588 }
 589 #endif
 590
 591 /*
 592  * Setup the trampoline code on the stack
 593  */
 594 static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp)
 595 {
 596         int i;
 597         long err = 0;
 598
 599         /* bctrl # call the handler */
 600         err |= __put_user(PPC_INST_BCTRL, &tramp[0]);
 601         /* addi r1, r1, __SIGNAL_FRAMESIZE  # Pop the dummy stackframe */
 602         err |= __put_user(PPC_INST_ADDI | __PPC_RT(R1) | __PPC_RA(R1) |
 603                           (__SIGNAL_FRAMESIZE & 0xffff), &tramp[1]);
 604         /* li r0, __NR_[rt_]sigreturn| */
 605         err |= __put_user(PPC_INST_ADDI | (syscall & 0xffff), &tramp[2]);
 606         /* sc */
 607         err |= __put_user(PPC_INST_SC, &tramp[3]);
 608
 609         /* Minimal traceback info */
 610         for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++)
 611                 err |= __put_user(0, &tramp[i]);
 612
 613         if (!err)
 614                 flush_icache_range((unsigned long) &tramp[0],
 615                            (unsigned long) &tramp[TRAMP_SIZE]);
 616
 617         return err;
 618 }
 619
 620 /*
 621  * Userspace code may pass a ucontext which doesn't include VSX added
 622  * at the end.  We need to check for this case.
 623  */
 624 #define UCONTEXTSIZEWITHOUTVSX \
 625                 (sizeof(struct ucontext) - 32*sizeof(long))
 626
 627 /*
 628  * Handle {get,set,swap}_context operations
 629  */
 630 SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx,
 631                 struct ucontext __user *, new_ctx, long, ctx_size)
 632 {
 633         sigset_t set;
 634         unsigned long new_msr = 0;
 635         int ctx_has_vsx_region = 0;
 636
 637         if (new_ctx &&
 638             get_user(new_msr, &new_ctx->uc_mcontext.gp_regs[PT_MSR]))
 639                 return -EFAULT;
 640         /*
 641          * Check that the context is not smaller than the original
 642          * size (with VMX but without VSX)
 643          */
 644         if (ctx_size < UCONTEXTSIZEWITHOUTVSX)
 645                 return -EINVAL;
 646         /*
 647          * If the new context state sets the MSR VSX bits but
 648          * it doesn't provide VSX state.
 649          */
 650         if ((ctx_size < sizeof(struct ucontext)) &&
 651             (new_msr & MSR_VSX))
 652                 return -EINVAL;
 653         /* Does the context have enough room to store VSX data? */
 654         if (ctx_size >= sizeof(struct ucontext))
 655                 ctx_has_vsx_region = 1;
 656
 657         if (old_ctx != NULL) {
 658                 if (!access_ok(old_ctx, ctx_size)
 659                     || setup_sigcontext(&old_ctx->uc_mcontext, current, 0, NULL, 0,
 660                                         ctx_has_vsx_region)
 661                     || __copy_to_user(&old_ctx->uc_sigmask,
 662                                       &current->blocked, sizeof(sigset_t)))
 663                         return -EFAULT;
 664         }
 665         if (new_ctx == NULL)
 666                 return 0;
 667         if (!access_ok(new_ctx, ctx_size) ||
 668             fault_in_pages_readable((u8 __user *)new_ctx, ctx_size))
 669                 return -EFAULT;
 670
 671         /*
 672          * If we get a fault copying the context into the kernel's
 673          * image of the user's registers, we can't just return -EFAULT
 674          * because the user's registers will be corrupted.  For instance
 675          * the NIP value may have been updated but not some of the
 676          * other registers.  Given that we have done the access_ok
 677          * and successfully read the first and last bytes of the region
 678          * above, this should only happen in an out-of-memory situation
 679          * or if another thread unmaps the region containing the context.
 680          * We kill the task with a SIGSEGV in this situation.
 681          */
 682
 683         if (__copy_from_user(&set, &new_ctx->uc_sigmask, sizeof(set)))
 684                 do_exit(SIGSEGV);
 685         set_current_blocked(&set);
 686         if (restore_sigcontext(current, NULL, 0, &new_ctx->uc_mcontext))
 687                 do_exit(SIGSEGV);
 688
 689         /* This returns like rt_sigreturn */
 690         set_thread_flag(TIF_RESTOREALL);
 691         return 0;
 692 }
 693
 694
 695 /*
 696  * Do a signal return; undo the signal stack.
 697  */
 698
 699 SYSCALL_DEFINE0(rt_sigreturn)
 700 {
 701         struct pt_regs *regs = current_pt_regs();
 702         struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1];
 703         sigset_t set;
 704 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 705         unsigned long msr;
 706 #endif
 707
 708         /* Always make any pending restarted system calls return -EINTR */
 709         current->restart_block.fn = do_no_restart_syscall;
 710
 711         if (!access_ok(uc, sizeof(*uc)))
 712                 goto badframe;
 713
 714         if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
 715                 goto badframe;
 716         set_current_blocked(&set);
 717
 718 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 719         /*
 720          * If there is a transactional state then throw it away.
 721          * The purpose of a sigreturn is to destroy all traces of the
 722          * signal frame, this includes any transactional state created
 723          * within in. We only check for suspended as we can never be
 724          * active in the kernel, we are active, there is nothing better to
 725          * do than go ahead and Bad Thing later.
 726          * The cause is not important as there will never be a
 727          * recheckpoint so it's not user visible.
 728          */
 729         if (MSR_TM_SUSPENDED(mfmsr()))
 730                 tm_reclaim_current(0);
 731
 732         /*
 733          * Disable MSR[TS] bit also, so, if there is an exception in the
 734          * code below (as a page fault in copy_ckvsx_to_user()), it does
 735          * not recheckpoint this task if there was a context switch inside
 736          * the exception.
 737          *
 738          * A major page fault can indirectly call schedule(). A reschedule
 739          * process in the middle of an exception can have a side effect
 740          * (Changing the CPU MSR[TS] state), since schedule() is called
 741          * with the CPU MSR[TS] disable and returns with MSR[TS]=Suspended
 742          * (switch_to() calls tm_recheckpoint() for the 'new' process). In
 743          * this case, the process continues to be the same in the CPU, but
 744          * the CPU state just changed.
 745          *
 746          * This can cause a TM Bad Thing, since the MSR in the stack will
 747          * have the MSR[TS]=0, and this is what will be used to RFID.
 748          *
 749          * Clearing MSR[TS] state here will avoid a recheckpoint if there
 750          * is any process reschedule in kernel space. The MSR[TS] state
 751          * does not need to be saved also, since it will be replaced with
 752          * the MSR[TS] that came from user context later, at
 753          * restore_tm_sigcontexts.
 754          */
 755         regs->msr &= ~MSR_TS_MASK;
 756
 757         if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR]))
 758                 goto badframe;
 759         if (MSR_TM_ACTIVE(msr)) {
 760                 /* We recheckpoint on return. */
 761                 struct ucontext __user *uc_transact;
 762
 763                 /* Trying to start TM on non TM system */
 764                 if (!cpu_has_feature(CPU_FTR_TM))
 765                         goto badframe;
 766
 767                 if (__get_user(uc_transact, &uc->uc_link))
 768                         goto badframe;
 769                 if (restore_tm_sigcontexts(current, &uc->uc_mcontext,
 770                                            &uc_transact->uc_mcontext))
 771                         goto badframe;
 772         } else
 773 #endif
 774         {
 775                 /*
 776                  * Fall through, for non-TM restore
 777                  *
 778                  * Unset MSR[TS] on the thread regs since MSR from user
 779                  * context does not have MSR active, and recheckpoint was
 780                  * not called since restore_tm_sigcontexts() was not called
 781                  * also.
 782                  *
 783                  * If not unsetting it, the code can RFID to userspace with
 784                  * MSR[TS] set, but without CPU in the proper state,
 785                  * causing a TM bad thing.
 786                  */
 787                 current->thread.regs->msr &= ~MSR_TS_MASK;
 788                 if (restore_sigcontext(current, NULL, 1, &uc->uc_mcontext))
 789                         goto badframe;
 790         }
 791
 792         if (restore_altstack(&uc->uc_stack))
 793                 goto badframe;
 794
 795         set_thread_flag(TIF_RESTOREALL);
 796         return 0;
 797
 798 badframe:
 799         signal_fault(current, regs, "rt_sigreturn", uc);
 800
 801         force_sig(SIGSEGV);
 802         return 0;
 803 }
 804
 805 int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
 806                 struct task_struct *tsk)
 807 {
 808         struct rt_sigframe __user *frame;
 809         unsigned long newsp = 0;
 810         long err = 0;
 811         struct pt_regs *regs = tsk->thread.regs;
 812 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 813         /* Save the thread's msr before get_tm_stackpointer() changes it */
 814         unsigned long msr = regs->msr;
 815 #endif
 816
 817         frame = get_sigframe(ksig, tsk, sizeof(*frame), 0);
 818         if (!access_ok(frame, sizeof(*frame)))
 819                 goto badframe;
 820
 821         err |= __put_user(&frame->info, &frame->pinfo);
 822         err |= __put_user(&frame->uc, &frame->puc);
 823         err |= copy_siginfo_to_user(&frame->info, &ksig->info);
 824         if (err)
 825                 goto badframe;
 826
 827         /* Create the ucontext.  */
 828         err |= __put_user(0, &frame->uc.uc_flags);
 829         err |= __save_altstack(&frame->uc.uc_stack, regs->gpr[1]);
 830 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 831         if (MSR_TM_ACTIVE(msr)) {
 832                 /* The ucontext_t passed to userland points to the second
 833                  * ucontext_t (for transactional state) with its uc_link ptr.
 834                  */
 835                 err |= __put_user(&frame->uc_transact, &frame->uc.uc_link);
 836                 err |= setup_tm_sigcontexts(&frame->uc.uc_mcontext,
 837                                             &frame->uc_transact.uc_mcontext,
 838                                             tsk, ksig->sig, NULL,
 839                                             (unsigned long)ksig->ka.sa.sa_handler,
 840                                             msr);
 841         } else
 842 #endif
 843         {
 844                 err |= __put_user(0, &frame->uc.uc_link);
 845                 err |= setup_sigcontext(&frame->uc.uc_mcontext, tsk, ksig->sig,
 846                                         NULL, (unsigned long)ksig->ka.sa.sa_handler,
 847                                         1);
 848         }
 849         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 850         if (err)
 851                 goto badframe;
 852
 853         /* Make sure signal handler doesn't get spurious FP exceptions */
 854         tsk->thread.fp_state.fpscr = 0;
 855
 856         /* Set up to return from userspace. */
 857         if (tsk->mm->context.vdso) {
 858                 regs->nip = VDSO64_SYMBOL(tsk->mm->context.vdso, sigtramp_rt64);
 859         } else {
 860                 err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]);
 861                 if (err)
 862                         goto badframe;
 863                 regs->nip = (unsigned long) &frame->tramp[0];
 864         }
 865
 866         /* Allocate a dummy caller frame for the signal handler. */
 867         newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE;
 868         err |= put_user(regs->gpr[1], (unsigned long __user *)newsp);
 869
 870         /* Set up "regs" so we "return" to the signal handler. */
 871         if (is_elf2_task()) {
 872                 regs->ctr = (unsigned long) ksig->ka.sa.sa_handler;
 873                 regs->gpr[12] = regs->ctr;
 874         } else {
 875                 /* Handler is *really* a pointer to the function descriptor for
 876                  * the signal routine.  The first entry in the function
 877                  * descriptor is the entry address of signal and the second
 878                  * entry is the TOC value we need to use.
 879                  */
 880                 func_descr_t __user *funct_desc_ptr =
 881                         (func_descr_t __user *) ksig->ka.sa.sa_handler;
 882
 883                 err |= get_user(regs->ctr, &funct_desc_ptr->entry);
 884                 err |= get_user(regs->gpr[2], &funct_desc_ptr->toc);
 885         }
 886
 887         /* enter the signal handler in native-endian mode */
 888         regs->msr &= ~MSR_LE;
 889         regs->msr |= (MSR_KERNEL & MSR_LE);
 890         regs->gpr[1] = newsp;
 891         regs->gpr[3] = ksig->sig;
 892         regs->result = 0;
 893         if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
 894                 err |= get_user(regs->gpr[4], (unsigned long __user *)&frame->pinfo);
 895                 err |= get_user(regs->gpr[5], (unsigned long __user *)&frame->puc);
 896                 regs->gpr[6] = (unsigned long) frame;
 897         } else {
 898                 regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext;
 899         }
 900         if (err)
 901                 goto badframe;
 902
 903         return 0;
 904
 905 badframe:
 906         signal_fault(current, regs, "handle_rt_signal64", frame);
 907
 908         return 1;
 909 }