arch/powerpc/kernel/signal_64.c

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