arch/sh/kernel/ptrace_32.c

   1 /*
   2  * SuperH process tracing
   3  *
   4  * Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
   5  * Copyright (C) 2002 - 2009  Paul Mundt
   6  *
   7  * Audit support by Yuichi Nakamura <ynakam@hitachisoft.jp>
   8  *
   9  * This file is subject to the terms and conditions of the GNU General Public
  10  * License.  See the file "COPYING" in the main directory of this archive
  11  * for more details.
  12  */
  13 #include <linux/kernel.h>
  14 #include <linux/sched.h>
  15 #include <linux/mm.h>
  16 #include <linux/smp.h>
  17 #include <linux/errno.h>
  18 #include <linux/ptrace.h>
  19 #include <linux/user.h>
  20 #include <linux/security.h>
  21 #include <linux/signal.h>
  22 #include <linux/io.h>
  23 #include <linux/audit.h>
  24 #include <linux/seccomp.h>
  25 #include <linux/tracehook.h>
  26 #include <linux/elf.h>
  27 #include <linux/regset.h>
  28 #include <linux/hw_breakpoint.h>
  29 #include <asm/uaccess.h>
  30 #include <asm/pgtable.h>
  31 #include <asm/system.h>
  32 #include <asm/processor.h>
  33 #include <asm/mmu_context.h>
  34 #include <asm/syscalls.h>
  35 #include <asm/fpu.h>
  36
  37 #define CREATE_TRACE_POINTS
  38 #include <trace/events/syscalls.h>
  39
  40 /*
  41  * This routine will get a word off of the process kernel stack.
  42  */
  43 static inline int get_stack_long(struct task_struct *task, int offset)
  44 {
  45         unsigned char *stack;
  46
  47         stack = (unsigned char *)task_pt_regs(task);
  48         stack += offset;
  49         return (*((int *)stack));
  50 }
  51
  52 /*
  53  * This routine will put a word on the process kernel stack.
  54  */
  55 static inline int put_stack_long(struct task_struct *task, int offset,
  56                                  unsigned long data)
  57 {
  58         unsigned char *stack;
  59
  60         stack = (unsigned char *)task_pt_regs(task);
  61         stack += offset;
  62         *(unsigned long *) stack = data;
  63         return 0;
  64 }
  65
  66 void ptrace_triggered(struct perf_event *bp, int nmi,
  67                       struct perf_sample_data *data, struct pt_regs *regs)
  68 {
  69         struct perf_event_attr attr;
  70
  71         /*
  72          * Disable the breakpoint request here since ptrace has defined a
  73          * one-shot behaviour for breakpoint exceptions.
  74          */
  75         attr = bp->attr;
  76         attr.disabled = true;
  77         modify_user_hw_breakpoint(bp, &attr);
  78 }
  79
  80 static int set_single_step(struct task_struct *tsk, unsigned long addr)
  81 {
  82         struct thread_struct *thread = &tsk->thread;
  83         struct perf_event *bp;
  84         struct perf_event_attr attr;
  85
  86         bp = thread->ptrace_bps[0];
  87         if (!bp) {
  88                 ptrace_breakpoint_init(&attr);
  89
  90                 attr.bp_addr = addr;
  91                 attr.bp_len = HW_BREAKPOINT_LEN_2;
  92                 attr.bp_type = HW_BREAKPOINT_R;
  93
  94                 bp = register_user_hw_breakpoint(&attr, ptrace_triggered, tsk);
  95                 if (IS_ERR(bp))
  96                         return PTR_ERR(bp);
  97
  98                 thread->ptrace_bps[0] = bp;
  99         } else {
 100                 int err;
 101
 102                 attr = bp->attr;
 103                 attr.bp_addr = addr;
 104                 err = modify_user_hw_breakpoint(bp, &attr);
 105                 if (unlikely(err))
 106                         return err;
 107         }
 108
 109         return 0;
 110 }
 111
 112 void user_enable_single_step(struct task_struct *child)
 113 {
 114         unsigned long pc = get_stack_long(child, offsetof(struct pt_regs, pc));
 115
 116         set_tsk_thread_flag(child, TIF_SINGLESTEP);
 117
 118         set_single_step(child, pc);
 119 }
 120
 121 void user_disable_single_step(struct task_struct *child)
 122 {
 123         clear_tsk_thread_flag(child, TIF_SINGLESTEP);
 124 }
 125
 126 /*
 127  * Called by kernel/ptrace.c when detaching..
 128  *
 129  * Make sure single step bits etc are not set.
 130  */
 131 void ptrace_disable(struct task_struct *child)
 132 {
 133         user_disable_single_step(child);
 134 }
 135
 136 static int genregs_get(struct task_struct *target,
 137                        const struct user_regset *regset,
 138                        unsigned int pos, unsigned int count,
 139                        void *kbuf, void __user *ubuf)
 140 {
 141         const struct pt_regs *regs = task_pt_regs(target);
 142         int ret;
 143
 144         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 145                                   regs->regs,
 146                                   0, 16 * sizeof(unsigned long));
 147         if (!ret)
 148                 /* PC, PR, SR, GBR, MACH, MACL, TRA */
 149                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 150                                           &regs->pc,
 151                                           offsetof(struct pt_regs, pc),
 152                                           sizeof(struct pt_regs));
 153         if (!ret)
 154                 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 155                                                sizeof(struct pt_regs), -1);
 156
 157         return ret;
 158 }
 159
 160 static int genregs_set(struct task_struct *target,
 161                        const struct user_regset *regset,
 162                        unsigned int pos, unsigned int count,
 163                        const void *kbuf, const void __user *ubuf)
 164 {
 165         struct pt_regs *regs = task_pt_regs(target);
 166         int ret;
 167
 168         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 169                                  regs->regs,
 170                                  0, 16 * sizeof(unsigned long));
 171         if (!ret && count > 0)
 172                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 173                                          &regs->pc,
 174                                          offsetof(struct pt_regs, pc),
 175                                          sizeof(struct pt_regs));
 176         if (!ret)
 177                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 178                                                 sizeof(struct pt_regs), -1);
 179
 180         return ret;
 181 }
 182
 183 #ifdef CONFIG_SH_FPU
 184 int fpregs_get(struct task_struct *target,
 185                const struct user_regset *regset,
 186                unsigned int pos, unsigned int count,
 187                void *kbuf, void __user *ubuf)
 188 {
 189         int ret;
 190
 191         ret = init_fpu(target);
 192         if (ret)
 193                 return ret;
 194
 195         if ((boot_cpu_data.flags & CPU_HAS_FPU))
 196                 return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 197                                            &target->thread.xstate->hardfpu, 0, -1);
 198
 199         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 200                                    &target->thread.xstate->softfpu, 0, -1);
 201 }
 202
 203 static int fpregs_set(struct task_struct *target,
 204                        const struct user_regset *regset,
 205                        unsigned int pos, unsigned int count,
 206                        const void *kbuf, const void __user *ubuf)
 207 {
 208         int ret;
 209
 210         ret = init_fpu(target);
 211         if (ret)
 212                 return ret;
 213
 214         set_stopped_child_used_math(target);
 215
 216         if ((boot_cpu_data.flags & CPU_HAS_FPU))
 217                 return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 218                                           &target->thread.xstate->hardfpu, 0, -1);
 219
 220         return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 221                                   &target->thread.xstate->softfpu, 0, -1);
 222 }
 223
 224 static int fpregs_active(struct task_struct *target,
 225                          const struct user_regset *regset)
 226 {
 227         return tsk_used_math(target) ? regset->n : 0;
 228 }
 229 #endif
 230
 231 #ifdef CONFIG_SH_DSP
 232 static int dspregs_get(struct task_struct *target,
 233                        const struct user_regset *regset,
 234                        unsigned int pos, unsigned int count,
 235                        void *kbuf, void __user *ubuf)
 236 {
 237         const struct pt_dspregs *regs =
 238                 (struct pt_dspregs *)&target->thread.dsp_status.dsp_regs;
 239         int ret;
 240
 241         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, regs,
 242                                   0, sizeof(struct pt_dspregs));
 243         if (!ret)
 244                 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 245                                                sizeof(struct pt_dspregs), -1);
 246
 247         return ret;
 248 }
 249
 250 static int dspregs_set(struct task_struct *target,
 251                        const struct user_regset *regset,
 252                        unsigned int pos, unsigned int count,
 253                        const void *kbuf, const void __user *ubuf)
 254 {
 255         struct pt_dspregs *regs =
 256                 (struct pt_dspregs *)&target->thread.dsp_status.dsp_regs;
 257         int ret;
 258
 259         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs,
 260                                  0, sizeof(struct pt_dspregs));
 261         if (!ret)
 262                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 263                                                 sizeof(struct pt_dspregs), -1);
 264
 265         return ret;
 266 }
 267
 268 static int dspregs_active(struct task_struct *target,
 269                           const struct user_regset *regset)
 270 {
 271         struct pt_regs *regs = task_pt_regs(target);
 272
 273         return regs->sr & SR_DSP ? regset->n : 0;
 274 }
 275 #endif
 276
 277 /*
 278  * These are our native regset flavours.
 279  */
 280 enum sh_regset {
 281         REGSET_GENERAL,
 282 #ifdef CONFIG_SH_FPU
 283         REGSET_FPU,
 284 #endif
 285 #ifdef CONFIG_SH_DSP
 286         REGSET_DSP,
 287 #endif
 288 };
 289
 290 static const struct user_regset sh_regsets[] = {
 291         /*
 292          * Format is:
 293          *      R0 --> R15
 294          *      PC, PR, SR, GBR, MACH, MACL, TRA
 295          */
 296         [REGSET_GENERAL] = {
 297                 .core_note_type = NT_PRSTATUS,
 298                 .n              = ELF_NGREG,
 299                 .size           = sizeof(long),
 300                 .align          = sizeof(long),
 301                 .get            = genregs_get,
 302                 .set            = genregs_set,
 303         },
 304
 305 #ifdef CONFIG_SH_FPU
 306         [REGSET_FPU] = {
 307                 .core_note_type = NT_PRFPREG,
 308                 .n              = sizeof(struct user_fpu_struct) / sizeof(long),
 309                 .size           = sizeof(long),
 310                 .align          = sizeof(long),
 311                 .get            = fpregs_get,
 312                 .set            = fpregs_set,
 313                 .active         = fpregs_active,
 314         },
 315 #endif
 316
 317 #ifdef CONFIG_SH_DSP
 318         [REGSET_DSP] = {
 319                 .n              = sizeof(struct pt_dspregs) / sizeof(long),
 320                 .size           = sizeof(long),
 321                 .align          = sizeof(long),
 322                 .get            = dspregs_get,
 323                 .set            = dspregs_set,
 324                 .active         = dspregs_active,
 325         },
 326 #endif
 327 };
 328
 329 static const struct user_regset_view user_sh_native_view = {
 330         .name           = "sh",
 331         .e_machine      = EM_SH,
 332         .regsets        = sh_regsets,
 333         .n              = ARRAY_SIZE(sh_regsets),
 334 };
 335
 336 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 337 {
 338         return &user_sh_native_view;
 339 }
 340
 341 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 342 {
 343         struct user * dummy = NULL;
 344         unsigned long __user *datap = (unsigned long __user *)data;
 345         int ret;
 346
 347         switch (request) {
 348         /* read the word at location addr in the USER area. */
 349         case PTRACE_PEEKUSR: {
 350                 unsigned long tmp;
 351
 352                 ret = -EIO;
 353                 if ((addr & 3) || addr < 0 ||
 354                     addr > sizeof(struct user) - 3)
 355                         break;
 356
 357                 if (addr < sizeof(struct pt_regs))
 358                         tmp = get_stack_long(child, addr);
 359                 else if (addr >= (long) &dummy->fpu &&
 360                          addr < (long) &dummy->u_fpvalid) {
 361                         if (!tsk_used_math(child)) {
 362                                 if (addr == (long)&dummy->fpu.fpscr)
 363                                         tmp = FPSCR_INIT;
 364                                 else
 365                                         tmp = 0;
 366                         } else
 367                                 tmp = ((long *)child->thread.xstate)
 368                                         [(addr - (long)&dummy->fpu) >> 2];
 369                 } else if (addr == (long) &dummy->u_fpvalid)
 370                         tmp = !!tsk_used_math(child);
 371                 else if (addr == PT_TEXT_ADDR)
 372                         tmp = child->mm->start_code;
 373                 else if (addr == PT_DATA_ADDR)
 374                         tmp = child->mm->start_data;
 375                 else if (addr == PT_TEXT_END_ADDR)
 376                         tmp = child->mm->end_code;
 377                 else if (addr == PT_TEXT_LEN)
 378                         tmp = child->mm->end_code - child->mm->start_code;
 379                 else
 380                         tmp = 0;
 381                 ret = put_user(tmp, datap);
 382                 break;
 383         }
 384
 385         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 386                 ret = -EIO;
 387                 if ((addr & 3) || addr < 0 ||
 388                     addr > sizeof(struct user) - 3)
 389                         break;
 390
 391                 if (addr < sizeof(struct pt_regs))
 392                         ret = put_stack_long(child, addr, data);
 393                 else if (addr >= (long) &dummy->fpu &&
 394                          addr < (long) &dummy->u_fpvalid) {
 395                         set_stopped_child_used_math(child);
 396                         ((long *)child->thread.xstate)
 397                                 [(addr - (long)&dummy->fpu) >> 2] = data;
 398                         ret = 0;
 399                 } else if (addr == (long) &dummy->u_fpvalid) {
 400                         conditional_stopped_child_used_math(data, child);
 401                         ret = 0;
 402                 }
 403                 break;
 404
 405         case PTRACE_GETREGS:
 406                 return copy_regset_to_user(child, &user_sh_native_view,
 407                                            REGSET_GENERAL,
 408                                            0, sizeof(struct pt_regs),
 409                                            (void __user *)data);
 410         case PTRACE_SETREGS:
 411                 return copy_regset_from_user(child, &user_sh_native_view,
 412                                              REGSET_GENERAL,
 413                                              0, sizeof(struct pt_regs),
 414                                              (const void __user *)data);
 415 #ifdef CONFIG_SH_FPU
 416         case PTRACE_GETFPREGS:
 417                 return copy_regset_to_user(child, &user_sh_native_view,
 418                                            REGSET_FPU,
 419                                            0, sizeof(struct user_fpu_struct),
 420                                            (void __user *)data);
 421         case PTRACE_SETFPREGS:
 422                 return copy_regset_from_user(child, &user_sh_native_view,
 423                                              REGSET_FPU,
 424                                              0, sizeof(struct user_fpu_struct),
 425                                              (const void __user *)data);
 426 #endif
 427 #ifdef CONFIG_SH_DSP
 428         case PTRACE_GETDSPREGS:
 429                 return copy_regset_to_user(child, &user_sh_native_view,
 430                                            REGSET_DSP,
 431                                            0, sizeof(struct pt_dspregs),
 432                                            (void __user *)data);
 433         case PTRACE_SETDSPREGS:
 434                 return copy_regset_from_user(child, &user_sh_native_view,
 435                                              REGSET_DSP,
 436                                              0, sizeof(struct pt_dspregs),
 437                                              (const void __user *)data);
 438 #endif
 439         default:
 440                 ret = ptrace_request(child, request, addr, data);
 441                 break;
 442         }
 443
 444         return ret;
 445 }
 446
 447 static inline int audit_arch(void)
 448 {
 449         int arch = EM_SH;
 450
 451 #ifdef CONFIG_CPU_LITTLE_ENDIAN
 452         arch |= __AUDIT_ARCH_LE;
 453 #endif
 454
 455         return arch;
 456 }
 457
 458 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
 459 {
 460         long ret = 0;
 461
 462         secure_computing(regs->regs[0]);
 463
 464         if (test_thread_flag(TIF_SYSCALL_TRACE) &&
 465             tracehook_report_syscall_entry(regs))
 466                 /*
 467                  * Tracing decided this syscall should not happen.
 468                  * We'll return a bogus call number to get an ENOSYS
 469                  * error, but leave the original number in regs->regs[0].
 470                  */
 471                 ret = -1L;
 472
 473         if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 474                 trace_sys_enter(regs, regs->regs[0]);
 475
 476         if (unlikely(current->audit_context))
 477                 audit_syscall_entry(audit_arch(), regs->regs[3],
 478                                     regs->regs[4], regs->regs[5],
 479                                     regs->regs[6], regs->regs[7]);
 480
 481         return ret ?: regs->regs[0];
 482 }
 483
 484 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
 485 {
 486         int step;
 487
 488         if (unlikely(current->audit_context))
 489                 audit_syscall_exit(AUDITSC_RESULT(regs->regs[0]),
 490                                    regs->regs[0]);
 491
 492         if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 493                 trace_sys_exit(regs, regs->regs[0]);
 494
 495         step = test_thread_flag(TIF_SINGLESTEP);
 496         if (step || test_thread_flag(TIF_SYSCALL_TRACE))
 497                 tracehook_report_syscall_exit(regs, step);
 498 }