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.xstate)[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                 init_fpu(task);
 118         } else if (last_task_used_math == task) {
 119                 enable_fpu();
 120                 save_fpu(task);
 121                 disable_fpu();
 122                 last_task_used_math = 0;
 123                 regs->sr |= SR_FD;
 124         }
 125
 126         ((long *)task->thread.xstate)[addr / sizeof(unsigned long)] = data;
 127         return 0;
 128 }
 129
 130 void user_enable_single_step(struct task_struct *child)
 131 {
 132         struct pt_regs *regs = child->thread.uregs;
 133
 134         regs->sr |= SR_SSTEP;   /* auto-resetting upon exception */
 135 }
 136
 137 void user_disable_single_step(struct task_struct *child)
 138 {
 139         struct pt_regs *regs = child->thread.uregs;
 140
 141         regs->sr &= ~SR_SSTEP;
 142 }
 143
 144 static int genregs_get(struct task_struct *target,
 145                        const struct user_regset *regset,
 146                        unsigned int pos, unsigned int count,
 147                        void *kbuf, void __user *ubuf)
 148 {
 149         const struct pt_regs *regs = task_pt_regs(target);
 150         int ret;
 151
 152         /* PC, SR, SYSCALL */
 153         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 154                                   &regs->pc,
 155                                   0, 3 * sizeof(unsigned long long));
 156
 157         /* R1 -> R63 */
 158         if (!ret)
 159                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 160                                           regs->regs,
 161                                           offsetof(struct pt_regs, regs[0]),
 162                                           63 * sizeof(unsigned long long));
 163         /* TR0 -> TR7 */
 164         if (!ret)
 165                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 166                                           regs->tregs,
 167                                           offsetof(struct pt_regs, tregs[0]),
 168                                           8 * sizeof(unsigned long long));
 169
 170         if (!ret)
 171                 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 172                                                sizeof(struct pt_regs), -1);
 173
 174         return ret;
 175 }
 176
 177 static int genregs_set(struct task_struct *target,
 178                        const struct user_regset *regset,
 179                        unsigned int pos, unsigned int count,
 180                        const void *kbuf, const void __user *ubuf)
 181 {
 182         struct pt_regs *regs = task_pt_regs(target);
 183         int ret;
 184
 185         /* PC, SR, SYSCALL */
 186         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 187                                  &regs->pc,
 188                                  0, 3 * sizeof(unsigned long long));
 189
 190         /* R1 -> R63 */
 191         if (!ret && count > 0)
 192                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 193                                          regs->regs,
 194                                          offsetof(struct pt_regs, regs[0]),
 195                                          63 * sizeof(unsigned long long));
 196
 197         /* TR0 -> TR7 */
 198         if (!ret && count > 0)
 199                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 200                                          regs->tregs,
 201                                          offsetof(struct pt_regs, tregs[0]),
 202                                          8 * sizeof(unsigned long long));
 203
 204         if (!ret)
 205                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 206                                                 sizeof(struct pt_regs), -1);
 207
 208         return ret;
 209 }
 210
 211 #ifdef CONFIG_SH_FPU
 212 int fpregs_get(struct task_struct *target,
 213                const struct user_regset *regset,
 214                unsigned int pos, unsigned int count,
 215                void *kbuf, void __user *ubuf)
 216 {
 217         int ret;
 218
 219         ret = init_fpu(target);
 220         if (ret)
 221                 return ret;
 222
 223         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 224                                    &target->thread.xstate->hardfpu, 0, -1);
 225 }
 226
 227 static int fpregs_set(struct task_struct *target,
 228                        const struct user_regset *regset,
 229                        unsigned int pos, unsigned int count,
 230                        const void *kbuf, const void __user *ubuf)
 231 {
 232         int ret;
 233
 234         ret = init_fpu(target);
 235         if (ret)
 236                 return ret;
 237
 238         set_stopped_child_used_math(target);
 239
 240         return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 241                                   &target->thread.xstate->hardfpu, 0, -1);
 242 }
 243
 244 static int fpregs_active(struct task_struct *target,
 245                          const struct user_regset *regset)
 246 {
 247         return tsk_used_math(target) ? regset->n : 0;
 248 }
 249 #endif
 250
 251 /*
 252  * These are our native regset flavours.
 253  */
 254 enum sh_regset {
 255         REGSET_GENERAL,
 256 #ifdef CONFIG_SH_FPU
 257         REGSET_FPU,
 258 #endif
 259 };
 260
 261 static const struct user_regset sh_regsets[] = {
 262         /*
 263          * Format is:
 264          *      PC, SR, SYSCALL,
 265          *      R1 --> R63,
 266          *      TR0 --> TR7,
 267          */
 268         [REGSET_GENERAL] = {
 269                 .core_note_type = NT_PRSTATUS,
 270                 .n              = ELF_NGREG,
 271                 .size           = sizeof(long long),
 272                 .align          = sizeof(long long),
 273                 .get            = genregs_get,
 274                 .set            = genregs_set,
 275         },
 276
 277 #ifdef CONFIG_SH_FPU
 278         [REGSET_FPU] = {
 279                 .core_note_type = NT_PRFPREG,
 280                 .n              = sizeof(struct user_fpu_struct) /
 281                                   sizeof(long long),
 282                 .size           = sizeof(long long),
 283                 .align          = sizeof(long long),
 284                 .get            = fpregs_get,
 285                 .set            = fpregs_set,
 286                 .active         = fpregs_active,
 287         },
 288 #endif
 289 };
 290
 291 static const struct user_regset_view user_sh64_native_view = {
 292         .name           = "sh64",
 293         .e_machine      = EM_SH,
 294         .regsets        = sh_regsets,
 295         .n              = ARRAY_SIZE(sh_regsets),
 296 };
 297
 298 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 299 {
 300         return &user_sh64_native_view;
 301 }
 302
 303 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 304 {
 305         int ret;
 306
 307         switch (request) {
 308         /* read the word at location addr in the USER area. */
 309         case PTRACE_PEEKUSR: {
 310                 unsigned long tmp;
 311
 312                 ret = -EIO;
 313                 if ((addr & 3) || addr < 0)
 314                         break;
 315
 316                 if (addr < sizeof(struct pt_regs))
 317                         tmp = get_stack_long(child, addr);
 318                 else if ((addr >= offsetof(struct user, fpu)) &&
 319                          (addr <  offsetof(struct user, u_fpvalid))) {
 320                         tmp = get_fpu_long(child, addr - offsetof(struct user, fpu));
 321                 } else if (addr == offsetof(struct user, u_fpvalid)) {
 322                         tmp = !!tsk_used_math(child);
 323                 } else {
 324                         break;
 325                 }
 326                 ret = put_user(tmp, (unsigned long *)data);
 327                 break;
 328         }
 329
 330         case PTRACE_POKEUSR:
 331                 /* write the word at location addr in the USER area. We must
 332                    disallow any changes to certain SR bits or u_fpvalid, since
 333                    this could crash the kernel or result in a security
 334                    loophole. */
 335                 ret = -EIO;
 336                 if ((addr & 3) || addr < 0)
 337                         break;
 338
 339                 if (addr < sizeof(struct pt_regs)) {
 340                         /* Ignore change of top 32 bits of SR */
 341                         if (addr == offsetof (struct pt_regs, sr)+4)
 342                         {
 343                                 ret = 0;
 344                                 break;
 345                         }
 346                         /* If lower 32 bits of SR, ignore non-user bits */
 347                         if (addr == offsetof (struct pt_regs, sr))
 348                         {
 349                                 long cursr = get_stack_long(child, addr);
 350                                 data &= ~(SR_MASK);
 351                                 data |= (cursr & SR_MASK);
 352                         }
 353                         ret = put_stack_long(child, addr, data);
 354                 }
 355                 else if ((addr >= offsetof(struct user, fpu)) &&
 356                          (addr <  offsetof(struct user, u_fpvalid))) {
 357                         ret = put_fpu_long(child, addr - offsetof(struct user, fpu), data);
 358                 }
 359                 break;
 360
 361         case PTRACE_GETREGS:
 362                 return copy_regset_to_user(child, &user_sh64_native_view,
 363                                            REGSET_GENERAL,
 364                                            0, sizeof(struct pt_regs),
 365                                            (void __user *)data);
 366         case PTRACE_SETREGS:
 367                 return copy_regset_from_user(child, &user_sh64_native_view,
 368                                              REGSET_GENERAL,
 369                                              0, sizeof(struct pt_regs),
 370                                              (const void __user *)data);
 371 #ifdef CONFIG_SH_FPU
 372         case PTRACE_GETFPREGS:
 373                 return copy_regset_to_user(child, &user_sh64_native_view,
 374                                            REGSET_FPU,
 375                                            0, sizeof(struct user_fpu_struct),
 376                                            (void __user *)data);
 377         case PTRACE_SETFPREGS:
 378                 return copy_regset_from_user(child, &user_sh64_native_view,
 379                                              REGSET_FPU,
 380                                              0, sizeof(struct user_fpu_struct),
 381                                              (const void __user *)data);
 382 #endif
 383         default:
 384                 ret = ptrace_request(child, request, addr, data);
 385                 break;
 386         }
 387
 388         return ret;
 389 }
 390
 391 asmlinkage int sh64_ptrace(long request, long pid, long addr, long data)
 392 {
 393 #define WPC_DBRMODE 0x0d104008
 394         static int first_call = 1;
 395
 396         lock_kernel();
 397         if (first_call) {
 398                 /* Set WPC.DBRMODE to 0.  This makes all debug events get
 399                  * delivered through RESVEC, i.e. into the handlers in entry.S.
 400                  * (If the kernel was downloaded using a remote gdb, WPC.DBRMODE
 401                  * would normally be left set to 1, which makes debug events get
 402                  * delivered through DBRVEC, i.e. into the remote gdb's
 403                  * handlers.  This prevents ptrace getting them, and confuses
 404                  * the remote gdb.) */
 405                 printk("DBRMODE set to 0 to permit native debugging\n");
 406                 poke_real_address_q(WPC_DBRMODE, 0);
 407                 first_call = 0;
 408         }
 409         unlock_kernel();
 410
 411         return sys_ptrace(request, pid, addr, data);
 412 }
 413
 414 static inline int audit_arch(void)
 415 {
 416         int arch = EM_SH;
 417
 418 #ifdef CONFIG_64BIT
 419         arch |= __AUDIT_ARCH_64BIT;
 420 #endif
 421 #ifdef CONFIG_CPU_LITTLE_ENDIAN
 422         arch |= __AUDIT_ARCH_LE;
 423 #endif
 424
 425         return arch;
 426 }
 427
 428 asmlinkage long long do_syscall_trace_enter(struct pt_regs *regs)
 429 {
 430         long long ret = 0;
 431
 432         secure_computing(regs->regs[9]);
 433
 434         if (test_thread_flag(TIF_SYSCALL_TRACE) &&
 435             tracehook_report_syscall_entry(regs))
 436                 /*
 437                  * Tracing decided this syscall should not happen.
 438                  * We'll return a bogus call number to get an ENOSYS
 439                  * error, but leave the original number in regs->regs[0].
 440                  */
 441                 ret = -1LL;
 442
 443         if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 444                 trace_sys_enter(regs, regs->regs[9]);
 445
 446         if (unlikely(current->audit_context))
 447                 audit_syscall_entry(audit_arch(), regs->regs[1],
 448                                     regs->regs[2], regs->regs[3],
 449                                     regs->regs[4], regs->regs[5]);
 450
 451         return ret ?: regs->regs[9];
 452 }
 453
 454 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
 455 {
 456         if (unlikely(current->audit_context))
 457                 audit_syscall_exit(AUDITSC_RESULT(regs->regs[9]),
 458                                    regs->regs[9]);
 459
 460         if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 461                 trace_sys_exit(regs, regs->regs[9]);
 462
 463         if (test_thread_flag(TIF_SYSCALL_TRACE))
 464                 tracehook_report_syscall_exit(regs, 0);
 465 }
 466
 467 /* Called with interrupts disabled */
 468 asmlinkage void do_single_step(unsigned long long vec, struct pt_regs *regs)
 469 {
 470         /* This is called after a single step exception (DEBUGSS).
 471            There is no need to change the PC, as it is a post-execution
 472            exception, as entry.S does not do anything to the PC for DEBUGSS.
 473            We need to clear the Single Step setting in SR to avoid
 474            continually stepping. */
 475         local_irq_enable();
 476         regs->sr &= ~SR_SSTEP;
 477         force_sig(SIGTRAP, current);
 478 }
 479
 480 /* Called with interrupts disabled */
 481 BUILD_TRAP_HANDLER(breakpoint)
 482 {
 483         TRAP_HANDLER_DECL;
 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 }