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