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 - 2008  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/slab.h>
  21 #include <linux/security.h>
  22 #include <linux/signal.h>
  23 #include <linux/io.h>
  24 #include <linux/audit.h>
  25 #include <linux/seccomp.h>
  26 #include <linux/tracehook.h>
  27 #include <linux/elf.h>
  28 #include <linux/regset.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
  36 /*
  37  * This routine will get a word off of the process kernel stack.
  38  */
  39 static inline int get_stack_long(struct task_struct *task, int offset)
  40 {
  41         unsigned char *stack;
  42
  43         stack = (unsigned char *)task_pt_regs(task);
  44         stack += offset;
  45         return (*((int *)stack));
  46 }
  47
  48 /*
  49  * This routine will put a word on the process kernel stack.
  50  */
  51 static inline int put_stack_long(struct task_struct *task, int offset,
  52                                  unsigned long data)
  53 {
  54         unsigned char *stack;
  55
  56         stack = (unsigned char *)task_pt_regs(task);
  57         stack += offset;
  58         *(unsigned long *) stack = data;
  59         return 0;
  60 }
  61
  62 void user_enable_single_step(struct task_struct *child)
  63 {
  64         /* Next scheduling will set up UBC */
  65         if (child->thread.ubc_pc == 0)
  66                 ubc_usercnt += 1;
  67
  68         child->thread.ubc_pc = get_stack_long(child,
  69                                 offsetof(struct pt_regs, pc));
  70
  71         set_tsk_thread_flag(child, TIF_SINGLESTEP);
  72 }
  73
  74 void user_disable_single_step(struct task_struct *child)
  75 {
  76         clear_tsk_thread_flag(child, TIF_SINGLESTEP);
  77
  78         /*
  79          * Ensure the UBC is not programmed at the next context switch.
  80          *
  81          * Normally this is not needed but there are sequences such as
  82          * singlestep, signal delivery, and continue that leave the
  83          * ubc_pc non-zero leading to spurious SIGTRAPs.
  84          */
  85         if (child->thread.ubc_pc != 0) {
  86                 ubc_usercnt -= 1;
  87                 child->thread.ubc_pc = 0;
  88         }
  89 }
  90
  91 /*
  92  * Called by kernel/ptrace.c when detaching..
  93  *
  94  * Make sure single step bits etc are not set.
  95  */
  96 void ptrace_disable(struct task_struct *child)
  97 {
  98         user_disable_single_step(child);
  99 }
 100
 101 static int genregs_get(struct task_struct *target,
 102                        const struct user_regset *regset,
 103                        unsigned int pos, unsigned int count,
 104                        void *kbuf, void __user *ubuf)
 105 {
 106         const struct pt_regs *regs = task_pt_regs(target);
 107         int ret;
 108
 109         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 110                                   regs->regs,
 111                                   0, 16 * sizeof(unsigned long));
 112         if (!ret)
 113                 /* PC, PR, SR, GBR, MACH, MACL, TRA */
 114                 ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 115                                           &regs->pc,
 116                                           offsetof(struct pt_regs, pc),
 117                                           sizeof(struct pt_regs));
 118         if (!ret)
 119                 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 120                                                sizeof(struct pt_regs), -1);
 121
 122         return ret;
 123 }
 124
 125 static int genregs_set(struct task_struct *target,
 126                        const struct user_regset *regset,
 127                        unsigned int pos, unsigned int count,
 128                        const void *kbuf, const void __user *ubuf)
 129 {
 130         struct pt_regs *regs = task_pt_regs(target);
 131         int ret;
 132
 133         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 134                                  regs->regs,
 135                                  0, 16 * sizeof(unsigned long));
 136         if (!ret && count > 0)
 137                 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 138                                          &regs->pc,
 139                                          offsetof(struct pt_regs, pc),
 140                                          sizeof(struct pt_regs));
 141         if (!ret)
 142                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 143                                                 sizeof(struct pt_regs), -1);
 144
 145         return ret;
 146 }
 147
 148 #ifdef CONFIG_SH_DSP
 149 static int dspregs_get(struct task_struct *target,
 150                        const struct user_regset *regset,
 151                        unsigned int pos, unsigned int count,
 152                        void *kbuf, void __user *ubuf)
 153 {
 154         const struct pt_dspregs *regs = task_pt_dspregs(target);
 155         int ret;
 156
 157         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, regs,
 158                                   0, sizeof(struct pt_dspregs));
 159         if (!ret)
 160                 ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 161                                                sizeof(struct pt_dspregs), -1);
 162
 163         return ret;
 164 }
 165
 166 static int dspregs_set(struct task_struct *target,
 167                        const struct user_regset *regset,
 168                        unsigned int pos, unsigned int count,
 169                        const void *kbuf, const void __user *ubuf)
 170 {
 171         struct pt_dspregs *regs = task_pt_dspregs(target);
 172         int ret;
 173
 174         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs,
 175                                  0, sizeof(struct pt_dspregs));
 176         if (!ret)
 177                 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 178                                                 sizeof(struct pt_dspregs), -1);
 179
 180         return ret;
 181 }
 182
 183 static int dspregs_active(struct task_struct *target,
 184                           const struct user_regset *regset)
 185 {
 186         struct pt_regs *regs = task_pt_regs(target);
 187
 188         return regs->sr & SR_DSP ? regset->n : 0;
 189 }
 190 #endif
 191
 192 /*
 193  * These are our native regset flavours.
 194  */
 195 enum sh_regset {
 196         REGSET_GENERAL,
 197 #ifdef CONFIG_SH_DSP
 198         REGSET_DSP,
 199 #endif
 200 };
 201
 202 static const struct user_regset sh_regsets[] = {
 203         /*
 204          * Format is:
 205          *      R0 --> R15
 206          *      PC, PR, SR, GBR, MACH, MACL, TRA
 207          */
 208         [REGSET_GENERAL] = {
 209                 .core_note_type = NT_PRSTATUS,
 210                 .n              = ELF_NGREG,
 211                 .size           = sizeof(long),
 212                 .align          = sizeof(long),
 213                 .get            = genregs_get,
 214                 .set            = genregs_set,
 215         },
 216
 217 #ifdef CONFIG_SH_DSP
 218         [REGSET_DSP] = {
 219                 .n              = sizeof(struct pt_dspregs) / sizeof(long),
 220                 .size           = sizeof(long),
 221                 .align          = sizeof(long),
 222                 .get            = dspregs_get,
 223                 .set            = dspregs_set,
 224                 .active         = dspregs_active,
 225         },
 226 #endif
 227 };
 228
 229 static const struct user_regset_view user_sh_native_view = {
 230         .name           = "sh",
 231         .e_machine      = EM_SH,
 232         .regsets        = sh_regsets,
 233         .n              = ARRAY_SIZE(sh_regsets),
 234 };
 235
 236 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 237 {
 238         return &user_sh_native_view;
 239 }
 240
 241 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 242 {
 243         struct user * dummy = NULL;
 244         unsigned long __user *datap = (unsigned long __user *)data;
 245         int ret;
 246
 247         switch (request) {
 248         /* read the word at location addr in the USER area. */
 249         case PTRACE_PEEKUSR: {
 250                 unsigned long tmp;
 251
 252                 ret = -EIO;
 253                 if ((addr & 3) || addr < 0 ||
 254                     addr > sizeof(struct user) - 3)
 255                         break;
 256
 257                 if (addr < sizeof(struct pt_regs))
 258                         tmp = get_stack_long(child, addr);
 259                 else if (addr >= (long) &dummy->fpu &&
 260                          addr < (long) &dummy->u_fpvalid) {
 261                         if (!tsk_used_math(child)) {
 262                                 if (addr == (long)&dummy->fpu.fpscr)
 263                                         tmp = FPSCR_INIT;
 264                                 else
 265                                         tmp = 0;
 266                         } else
 267                                 tmp = ((long *)&child->thread.fpu)
 268                                         [(addr - (long)&dummy->fpu) >> 2];
 269                 } else if (addr == (long) &dummy->u_fpvalid)
 270                         tmp = !!tsk_used_math(child);
 271                 else
 272                         tmp = 0;
 273                 ret = put_user(tmp, datap);
 274                 break;
 275         }
 276
 277         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 278                 ret = -EIO;
 279                 if ((addr & 3) || addr < 0 ||
 280                     addr > sizeof(struct user) - 3)
 281                         break;
 282
 283                 if (addr < sizeof(struct pt_regs))
 284                         ret = put_stack_long(child, addr, data);
 285                 else if (addr >= (long) &dummy->fpu &&
 286                          addr < (long) &dummy->u_fpvalid) {
 287                         set_stopped_child_used_math(child);
 288                         ((long *)&child->thread.fpu)
 289                                 [(addr - (long)&dummy->fpu) >> 2] = data;
 290                         ret = 0;
 291                 } else if (addr == (long) &dummy->u_fpvalid) {
 292                         conditional_stopped_child_used_math(data, child);
 293                         ret = 0;
 294                 }
 295                 break;
 296
 297         case PTRACE_GETREGS:
 298                 return copy_regset_to_user(child, &user_sh_native_view,
 299                                            REGSET_GENERAL,
 300                                            0, sizeof(struct pt_regs),
 301                                            (void __user *)data);
 302         case PTRACE_SETREGS:
 303                 return copy_regset_from_user(child, &user_sh_native_view,
 304                                              REGSET_GENERAL,
 305                                              0, sizeof(struct pt_regs),
 306                                              (const void __user *)data);
 307 #ifdef CONFIG_SH_DSP
 308         case PTRACE_GETDSPREGS:
 309                 return copy_regset_to_user(child, &user_sh_native_view,
 310                                            REGSET_DSP,
 311                                            0, sizeof(struct pt_dspregs),
 312                                            (void __user *)data);
 313         case PTRACE_SETDSPREGS:
 314                 return copy_regset_from_user(child, &user_sh_native_view,
 315                                              REGSET_DSP,
 316                                              0, sizeof(struct pt_dspregs),
 317                                              (const void __user *)data);
 318 #endif
 319 #ifdef CONFIG_BINFMT_ELF_FDPIC
 320         case PTRACE_GETFDPIC: {
 321                 unsigned long tmp = 0;
 322
 323                 switch (addr) {
 324                 case PTRACE_GETFDPIC_EXEC:
 325                         tmp = child->mm->context.exec_fdpic_loadmap;
 326                         break;
 327                 case PTRACE_GETFDPIC_INTERP:
 328                         tmp = child->mm->context.interp_fdpic_loadmap;
 329                         break;
 330                 default:
 331                         break;
 332                 }
 333
 334                 ret = 0;
 335                 if (put_user(tmp, datap)) {
 336                         ret = -EFAULT;
 337                         break;
 338                 }
 339                 break;
 340         }
 341 #endif
 342         default:
 343                 ret = ptrace_request(child, request, addr, data);
 344                 break;
 345         }
 346
 347         return ret;
 348 }
 349
 350 static inline int audit_arch(void)
 351 {
 352         int arch = EM_SH;
 353
 354 #ifdef CONFIG_CPU_LITTLE_ENDIAN
 355         arch |= __AUDIT_ARCH_LE;
 356 #endif
 357
 358         return arch;
 359 }
 360
 361 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
 362 {
 363         long ret = 0;
 364
 365         secure_computing(regs->regs[0]);
 366
 367         if (test_thread_flag(TIF_SYSCALL_TRACE) &&
 368             tracehook_report_syscall_entry(regs))
 369                 /*
 370                  * Tracing decided this syscall should not happen.
 371                  * We'll return a bogus call number to get an ENOSYS
 372                  * error, but leave the original number in regs->regs[0].
 373                  */
 374                 ret = -1L;
 375
 376         if (unlikely(current->audit_context))
 377                 audit_syscall_entry(audit_arch(), regs->regs[3],
 378                                     regs->regs[4], regs->regs[5],
 379                                     regs->regs[6], regs->regs[7]);
 380
 381         return ret ?: regs->regs[0];
 382 }
 383
 384 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
 385 {
 386         int step;
 387
 388         if (unlikely(current->audit_context))
 389                 audit_syscall_exit(AUDITSC_RESULT(regs->regs[0]),
 390                                    regs->regs[0]);
 391
 392         step = test_thread_flag(TIF_SINGLESTEP);
 393         if (step || test_thread_flag(TIF_SYSCALL_TRACE))
 394                 tracehook_report_syscall_exit(regs, step);
 395 }