arch/sh/kernel/ptrace_64.c

   1 /*
   2  * arch/sh/kernel/ptrace_64.c
   3  *
   4  * Copyright (C) 2000, 2001  Paolo Alberelli
   5  * Copyright (C) 2003 - 2008  Paul Mundt
   6  *
   7  * Started from SH3/4 version:
   8  *   SuperH version:   Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
   9  *
  10  *   Original x86 implementation:
  11  *      By Ross Biro 1/23/92
  12  *      edited by Linus Torvalds
  13  *
  14  * This file is subject to the terms and conditions of the GNU General Public
  15  * License.  See the file "COPYING" in the main directory of this archive
  16  * for more details.
  17  */
  18 #include <linux/kernel.h>
  19 #include <linux/rwsem.h>
  20 #include <linux/sched.h>
  21 #include <linux/mm.h>
  22 #include <linux/smp.h>
  23 #include <linux/smp_lock.h>
  24 #include <linux/errno.h>
  25 #include <linux/ptrace.h>
  26 #include <linux/user.h>
  27 #include <linux/signal.h>
  28 #include <linux/syscalls.h>
  29 #include <linux/audit.h>
  30 #include <linux/seccomp.h>
  31 #include <linux/tracehook.h>
  32 #include <linux/elf.h>
  33 #include <linux/regset.h>
  34 #include <asm/io.h>
  35 #include <asm/uaccess.h>
  36 #include <asm/pgtable.h>
  37 #include <asm/system.h>
  38 #include <asm/processor.h>
  39 #include <asm/mmu_context.h>
  40 #include <asm/syscalls.h>
  41 #include <asm/fpu.h>
  42
  43 #define CREATE_TRACE_POINTS
  44 #include <trace/events/syscalls.h>
  45
  46 /* This mask defines the bits of the SR which the user is not allowed to
  47    change, which are everything except S, Q, M, PR, SZ, FR. */
  48 #define SR_MASK      (0xffff8cfd)
  49
  50 /*
  51  * does not yet catch signals sent when the child dies.
  52  * in exit.c or in signal.c.
  53  */
  54
  55 /*
  56  * This routine will get a word from the user area in the process kernel stack.
  57  */
  58 static inline int get_stack_long(struct task_struct *task, int offset)
  59 {
  60         unsigned char *stack;
  61
  62         stack = (unsigned char *)(task->thread.uregs);
  63         stack += offset;
  64         return (*((int *)stack));
  65 }
  66
  67 static inline unsigned long
  68 get_fpu_long(struct task_struct *task, unsigned long addr)
  69 {
  70         unsigned long tmp;
  71         struct pt_regs *regs;
  72         regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;
  73
  74         if (!tsk_used_math(task)) {
  75                 if (addr == offsetof(struct user_fpu_struct, fpscr)) {
  76                         tmp = FPSCR_INIT;
  77                 } else {
  78                         tmp = 0xffffffffUL; /* matches initial value in fpu.c */
  79                 }
  80                 return tmp;
  81         }
  82
  83         if (last_task_used_math == task) {
  84                 enable_fpu();
  85                 save_fpu(task);
  86                 disable_fpu();
  87                 last_task_used_math = 0;
  88                 regs->sr |= SR_FD;
  89         }
  90
  91         tmp = ((long *)&task->thread.fpu)[addr / sizeof(unsigned long)];
  92         return tmp;
  93 }
  94
  95 /*
  96  * This routine will put a word into the user area in the process kernel stack.
  97  */
  98 static inline int put_stack_long(struct task_struct *task, int offset,
  99                                  unsigned long data)
 100 {
 101         unsigned char *stack;
 102
 103         stack = (unsigned char *)(task->thread.uregs);
 104         stack += offset;
 105         *(unsigned long *) stack = data;
 106         return 0;
 107 }
 108
 109 static inline int
 110 put_fpu_long(struct task_struct *task, unsigned long addr, unsigned long data)
 111 {
 112         struct pt_regs *regs;
 113
 114         regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;
 115
 116         if (!tsk_used_math(task)) {
 117                 fpinit(&task->thread.fpu.hard);
 118                 set_stopped_child_used_math(task);
 119         } else if (last_task_used_math == task) {
 120                 enable_fpu();
 121                 save_fpu(task);
 122                 disable_fpu();
 123                 last_task_used_math = 0;
 124                 regs->sr |= SR_FD;
 125         }
 126
 127         ((long *)&task->thread.fpu)[addr / sizeof(unsigned long)] = data;
 128         return 0;
 129 }
 130
 131 void user_enable_single_step(struct task_struct *child)
 132 {
 133         struct pt_regs *regs = child->thread.uregs;
 134
 135         regs->sr |= SR_SSTEP;   /* auto-resetting upon exception */
 136 }
 137
 138 void user_disable_single_step(struct task_struct *child)
 139 {
 140         struct pt_regs *regs = child->thread.uregs;
 141
 142         regs->sr &= ~SR_SSTEP;
 143 }
 144
 145 static int genregs_get(struct task_struct *target,
 146                        const struct user_regset *regset,
 147                        unsigned int pos, unsigned int count,
 148                        void *kbuf, void __user *ubuf)
 149 {
 150         const struct pt_regs *regs = task_pt_regs(target);
 151         int ret;
 152
 153         /* PC, SR, SYSCALL */
 154         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 155                                   &regs->pc,
 156                                   0, 3 * sizeof(unsigned long long));
 157
 158         /* R1 -> R63 */
 159         if (!ret)
 160                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 161                                           regs->regs,
 162                                           offsetof(struct pt_regs, regs[0]),
 163                                           63 * sizeof(unsigned long long));
 164         /* TR0 -> TR7 */
 165         if (!ret)
 166                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 167                                           regs->tregs,
 168                                           offsetof(struct pt_regs, tregs[0]),
 169                                           8 * sizeof(unsigned long long));
 170
 171         if (!ret)
 172                 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 173                                                sizeof(struct pt_regs), -1);
 174
 175         return ret;
 176 }
 177
 178 static int genregs_set(struct task_struct *target,
 179                        const struct user_regset *regset,
 180                        unsigned int pos, unsigned int count,
 181                        const void *kbuf, const void __user *ubuf)
 182 {
 183         struct pt_regs *regs = task_pt_regs(target);
 184         int ret;
 185
 186         /* PC, SR, SYSCALL */
 187         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 188                                  &regs->pc,
 189                                  0, 3 * sizeof(unsigned long long));
 190
 191         /* R1 -> R63 */
 192         if (!ret && count > 0)
 193                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 194                                          regs->regs,
 195                                          offsetof(struct pt_regs, regs[0]),
 196                                          63 * sizeof(unsigned long long));
 197
 198         /* TR0 -> TR7 */
 199         if (!ret && count > 0)
 200                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 201                                          regs->tregs,
 202                                          offsetof(struct pt_regs, tregs[0]),
 203                                          8 * sizeof(unsigned long long));
 204
 205         if (!ret)
 206                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 207                                                 sizeof(struct pt_regs), -1);
 208
 209         return ret;
 210 }
 211
 212 #ifdef CONFIG_SH_FPU
 213 int fpregs_get(struct task_struct *target,
 214                const struct user_regset *regset,
 215                unsigned int pos, unsigned int count,
 216                void *kbuf, void __user *ubuf)
 217 {
 218         int ret;
 219
 220         ret = init_fpu(target);
 221         if (ret)
 222                 return ret;
 223
 224         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 225                                    &target->thread.fpu.hard, 0, -1);
 226 }
 227
 228 static int fpregs_set(struct task_struct *target,
 229                        const struct user_regset *regset,
 230                        unsigned int pos, unsigned int count,
 231                        const void *kbuf, const void __user *ubuf)
 232 {
 233         int ret;
 234
 235         ret = init_fpu(target);
 236         if (ret)
 237                 return ret;
 238
 239         set_stopped_child_used_math(target);
 240
 241         return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 242                                   &target->thread.fpu.hard, 0, -1);
 243 }
 244
 245 static int fpregs_active(struct task_struct *target,
 246                          const struct user_regset *regset)
 247 {
 248         return tsk_used_math(target) ? regset->n : 0;
 249 }
 250 #endif
 251
 252 /*
 253  * These are our native regset flavours.
 254  */
 255 enum sh_regset {
 256         REGSET_GENERAL,
 257 #ifdef CONFIG_SH_FPU
 258         REGSET_FPU,
 259 #endif
 260 };
 261
 262 static const struct user_regset sh_regsets[] = {
 263         /*
 264          * Format is:
 265          *      PC, SR, SYSCALL,
 266          *      R1 --> R63,
 267          *      TR0 --> TR7,
 268          */
 269         [REGSET_GENERAL] = {
 270                 .core_note_type = NT_PRSTATUS,
 271                 .n              = ELF_NGREG,
 272                 .size           = sizeof(long long),
 273                 .align          = sizeof(long long),
 274                 .get            = genregs_get,
 275                 .set            = genregs_set,
 276         },
 277
 278 #ifdef CONFIG_SH_FPU
 279         [REGSET_FPU] = {
 280                 .core_note_type = NT_PRFPREG,
 281                 .n              = sizeof(struct user_fpu_struct) /
 282                                   sizeof(long long),
 283                 .size           = sizeof(long long),
 284                 .align          = sizeof(long long),
 285                 .get            = fpregs_get,
 286                 .set            = fpregs_set,
 287                 .active         = fpregs_active,
 288         },
 289 #endif
 290 };
 291
 292 static const struct user_regset_view user_sh64_native_view = {
 293         .name           = "sh64",
 294         .e_machine      = EM_SH,
 295         .regsets        = sh_regsets,
 296         .n              = ARRAY_SIZE(sh_regsets),
 297 };
 298
 299 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 300 {
 301         return &user_sh64_native_view;
 302 }
 303
 304 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 305 {
 306         int ret;
 307
 308         switch (request) {
 309         /* read the word at location addr in the USER area. */
 310         case PTRACE_PEEKUSR: {
 311                 unsigned long tmp;
 312
 313                 ret = -EIO;
 314                 if ((addr & 3) || addr < 0)
 315                         break;
 316
 317                 if (addr < sizeof(struct pt_regs))
 318                         tmp = get_stack_long(child, addr);
 319                 else if ((addr >= offsetof(struct user, fpu)) &&
 320                          (addr <  offsetof(struct user, u_fpvalid))) {
 321                         tmp = get_fpu_long(child, addr - offsetof(struct user, fpu));
 322                 } else if (addr == offsetof(struct user, u_fpvalid)) {
 323                         tmp = !!tsk_used_math(child);
 324                 } else {
 325                         break;
 326                 }
 327                 ret = put_user(tmp, (unsigned long *)data);
 328                 break;
 329         }
 330
 331         case PTRACE_POKEUSR:
 332                 /* write the word at location addr in the USER area. We must
 333                    disallow any changes to certain SR bits or u_fpvalid, since
 334                    this could crash the kernel or result in a security
 335                    loophole. */
 336                 ret = -EIO;
 337                 if ((addr & 3) || addr < 0)
 338                         break;
 339
 340                 if (addr < sizeof(struct pt_regs)) {
 341                         /* Ignore change of top 32 bits of SR */
 342                         if (addr == offsetof (struct pt_regs, sr)+4)
 343                         {
 344                                 ret = 0;
 345                                 break;
 346                         }
 347                         /* If lower 32 bits of SR, ignore non-user bits */
 348                         if (addr == offsetof (struct pt_regs, sr))
 349                         {
 350                                 long cursr = get_stack_long(child, addr);
 351                                 data &= ~(SR_MASK);
 352                                 data |= (cursr & SR_MASK);
 353                         }
 354                         ret = put_stack_long(child, addr, data);
 355                 }
 356                 else if ((addr >= offsetof(struct user, fpu)) &&
 357                          (addr <  offsetof(struct user, u_fpvalid))) {
 358                         ret = put_fpu_long(child, addr - offsetof(struct user, fpu), data);
 359                 }
 360                 break;
 361
 362         case PTRACE_GETREGS:
 363                 return copy_regset_to_user(child, &user_sh64_native_view,
 364                                            REGSET_GENERAL,
 365                                            0, sizeof(struct pt_regs),
 366                                            (void __user *)data);
 367         case PTRACE_SETREGS:
 368                 return copy_regset_from_user(child, &user_sh64_native_view,
 369                                              REGSET_GENERAL,
 370                                              0, sizeof(struct pt_regs),
 371                                              (const void __user *)data);
 372 #ifdef CONFIG_SH_FPU
 373         case PTRACE_GETFPREGS:
 374                 return copy_regset_to_user(child, &user_sh64_native_view,
 375                                            REGSET_FPU,
 376                                            0, sizeof(struct user_fpu_struct),
 377                                            (void __user *)data);
 378         case PTRACE_SETFPREGS:
 379                 return copy_regset_from_user(child, &user_sh64_native_view,
 380                                              REGSET_FPU,
 381                                              0, sizeof(struct user_fpu_struct),
 382                                              (const void __user *)data);
 383 #endif
 384         default:
 385                 ret = ptrace_request(child, request, addr, data);
 386                 break;
 387         }
 388
 389         return ret;
 390 }
 391
 392 asmlinkage int sh64_ptrace(long request, long pid, long addr, long data)
 393 {
 394 #define WPC_DBRMODE 0x0d104008
 395         static int first_call = 1;
 396
 397         lock_kernel();
 398         if (first_call) {
 399                 /* Set WPC.DBRMODE to 0.  This makes all debug events get
 400                  * delivered through RESVEC, i.e. into the handlers in entry.S.
 401                  * (If the kernel was downloaded using a remote gdb, WPC.DBRMODE
 402                  * would normally be left set to 1, which makes debug events get
 403                  * delivered through DBRVEC, i.e. into the remote gdb's
 404                  * handlers.  This prevents ptrace getting them, and confuses
 405                  * the remote gdb.) */
 406                 printk("DBRMODE set to 0 to permit native debugging\n");
 407                 poke_real_address_q(WPC_DBRMODE, 0);
 408                 first_call = 0;
 409         }
 410         unlock_kernel();
 411
 412         return sys_ptrace(request, pid, addr, data);
 413 }
 414
 415 static inline int audit_arch(void)
 416 {
 417         int arch = EM_SH;
 418
 419 #ifdef CONFIG_64BIT
 420         arch |= __AUDIT_ARCH_64BIT;
 421 #endif
 422 #ifdef CONFIG_CPU_LITTLE_ENDIAN
 423         arch |= __AUDIT_ARCH_LE;
 424 #endif
 425
 426         return arch;
 427 }
 428
 429 asmlinkage long long do_syscall_trace_enter(struct pt_regs *regs)
 430 {
 431         long long ret = 0;
 432
 433         secure_computing(regs->regs[9]);
 434
 435         if (test_thread_flag(TIF_SYSCALL_TRACE) &&
 436             tracehook_report_syscall_entry(regs))
 437                 /*
 438                  * Tracing decided this syscall should not happen.
 439                  * We'll return a bogus call number to get an ENOSYS
 440                  * error, but leave the original number in regs->regs[0].
 441                  */
 442                 ret = -1LL;
 443
 444         if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 445                 trace_sys_enter(regs, regs->regs[9]);
 446
 447         if (unlikely(current->audit_context))
 448                 audit_syscall_entry(audit_arch(), regs->regs[1],
 449                                     regs->regs[2], regs->regs[3],
 450                                     regs->regs[4], regs->regs[5]);
 451
 452         return ret ?: regs->regs[9];
 453 }
 454
 455 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
 456 {
 457         if (unlikely(current->audit_context))
 458                 audit_syscall_exit(AUDITSC_RESULT(regs->regs[9]),
 459                                    regs->regs[9]);
 460
 461         if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 462                 trace_sys_exit(regs, regs->regs[9]);
 463
 464         if (test_thread_flag(TIF_SYSCALL_TRACE))
 465                 tracehook_report_syscall_exit(regs, 0);
 466 }
 467
 468 /* Called with interrupts disabled */
 469 asmlinkage void do_single_step(unsigned long long vec, struct pt_regs *regs)
 470 {
 471         /* This is called after a single step exception (DEBUGSS).
 472            There is no need to change the PC, as it is a post-execution
 473            exception, as entry.S does not do anything to the PC for DEBUGSS.
 474            We need to clear the Single Step setting in SR to avoid
 475            continually stepping. */
 476         local_irq_enable();
 477         regs->sr &= ~SR_SSTEP;
 478         force_sig(SIGTRAP, current);
 479 }
 480
 481 /* Called with interrupts disabled */
 482 asmlinkage void do_software_break_point(unsigned long long vec,
 483                                         struct pt_regs *regs)
 484 {
 485         /* We need to forward step the PC, to counteract the backstep done
 486            in signal.c. */
 487         local_irq_enable();
 488         force_sig(SIGTRAP, current);
 489         regs->pc += 4;
 490 }
 491
 492 /*
 493  * Called by kernel/ptrace.c when detaching..
 494  *
 495  * Make sure single step bits etc are not set.
 496  */
 497 void ptrace_disable(struct task_struct *child)
 498 {
 499         user_disable_single_step(child);
 500 }