arch/blackfin/kernel/ptrace.c

   1 /*
   2  * linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
   3  * these modifications are Copyright 2004-2010 Analog Devices Inc.
   4  *
   5  * Licensed under the GPL-2
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/sched.h>
  10 #include <linux/mm.h>
  11 #include <linux/smp.h>
  12 #include <linux/elf.h>
  13 #include <linux/errno.h>
  14 #include <linux/ptrace.h>
  15 #include <linux/user.h>
  16 #include <linux/regset.h>
  17 #include <linux/signal.h>
  18 #include <linux/tracehook.h>
  19 #include <linux/uaccess.h>
  20
  21 #include <asm/page.h>
  22 #include <asm/pgtable.h>
  23 #include <asm/system.h>
  24 #include <asm/processor.h>
  25 #include <asm/asm-offsets.h>
  26 #include <asm/dma.h>
  27 #include <asm/fixed_code.h>
  28 #include <asm/cacheflush.h>
  29 #include <asm/mem_map.h>
  30 #include <asm/mmu_context.h>
  31
  32 /*
  33  * does not yet catch signals sent when the child dies.
  34  * in exit.c or in signal.c.
  35  */
  36
  37 /*
  38  * Get contents of register REGNO in task TASK.
  39  */
  40 static inline long
  41 get_reg(struct task_struct *task, unsigned long regno,
  42         unsigned long __user *datap)
  43 {
  44         long tmp;
  45         struct pt_regs *regs = task_pt_regs(task);
  46
  47         if (regno & 3 || regno > PT_LAST_PSEUDO)
  48                 return -EIO;
  49
  50         switch (regno) {
  51         case PT_TEXT_ADDR:
  52                 tmp = task->mm->start_code;
  53                 break;
  54         case PT_TEXT_END_ADDR:
  55                 tmp = task->mm->end_code;
  56                 break;
  57         case PT_DATA_ADDR:
  58                 tmp = task->mm->start_data;
  59                 break;
  60         case PT_USP:
  61                 tmp = task->thread.usp;
  62                 break;
  63         default:
  64                 if (regno < sizeof(*regs)) {
  65                         void *reg_ptr = regs;
  66                         tmp = *(long *)(reg_ptr + regno);
  67                 } else
  68                         return -EIO;
  69         }
  70
  71         return put_user(tmp, datap);
  72 }
  73
  74 /*
  75  * Write contents of register REGNO in task TASK.
  76  */
  77 static inline int
  78 put_reg(struct task_struct *task, unsigned long regno, unsigned long data)
  79 {
  80         struct pt_regs *regs = task_pt_regs(task);
  81
  82         if (regno & 3 || regno > PT_LAST_PSEUDO)
  83                 return -EIO;
  84
  85         switch (regno) {
  86         case PT_PC:
  87                 /*********************************************************************/
  88                 /* At this point the kernel is most likely in exception.             */
  89                 /* The RETX register will be used to populate the pc of the process. */
  90                 /*********************************************************************/
  91                 regs->retx = data;
  92                 regs->pc = data;
  93                 break;
  94         case PT_RETX:
  95                 break;          /* regs->retx = data; break; */
  96         case PT_USP:
  97                 regs->usp = data;
  98                 task->thread.usp = data;
  99                 break;
 100         case PT_SYSCFG: /* don't let userspace screw with this */
 101                 if ((data & ~1) != 0x6)
 102                         pr_warning("ptrace: ignore syscfg write of %#lx\n", data);
 103                 break;          /* regs->syscfg = data; break; */
 104         default:
 105                 if (regno < sizeof(*regs)) {
 106                         void *reg_offset = regs;
 107                         *(long *)(reg_offset + regno) = data;
 108                 }
 109                 /* Ignore writes to pseudo registers */
 110         }
 111
 112         return 0;
 113 }
 114
 115 /*
 116  * check that an address falls within the bounds of the target process's memory mappings
 117  */
 118 int
 119 is_user_addr_valid(struct task_struct *child, unsigned long start, unsigned long len)
 120 {
 121         struct vm_area_struct *vma;
 122         struct sram_list_struct *sraml;
 123
 124         /* overflow */
 125         if (start + len < start)
 126                 return -EIO;
 127
 128         vma = find_vma(child->mm, start);
 129         if (vma && start >= vma->vm_start && start + len <= vma->vm_end)
 130                         return 0;
 131
 132         for (sraml = child->mm->context.sram_list; sraml; sraml = sraml->next)
 133                 if (start >= (unsigned long)sraml->addr
 134                     && start + len < (unsigned long)sraml->addr + sraml->length)
 135                         return 0;
 136
 137         if (start >= FIXED_CODE_START && start + len < FIXED_CODE_END)
 138                 return 0;
 139
 140 #ifdef CONFIG_APP_STACK_L1
 141         if (child->mm->context.l1_stack_save)
 142                 if (start >= (unsigned long)l1_stack_base &&
 143                         start + len < (unsigned long)l1_stack_base + l1_stack_len)
 144                         return 0;
 145 #endif
 146
 147         return -EIO;
 148 }
 149
 150 /*
 151  * retrieve the contents of Blackfin userspace general registers
 152  */
 153 static int genregs_get(struct task_struct *target,
 154                        const struct user_regset *regset,
 155                        unsigned int pos, unsigned int count,
 156                        void *kbuf, void __user *ubuf)
 157 {
 158         struct pt_regs *regs = task_pt_regs(target);
 159         int ret;
 160
 161         /* This sucks ... */
 162         regs->usp = target->thread.usp;
 163
 164         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 165                                   regs, 0, sizeof(*regs));
 166         if (ret < 0)
 167                 return ret;
 168
 169         return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 170                                         sizeof(*regs), -1);
 171 }
 172
 173 /*
 174  * update the contents of the Blackfin userspace general registers
 175  */
 176 static int genregs_set(struct task_struct *target,
 177                        const struct user_regset *regset,
 178                        unsigned int pos, unsigned int count,
 179                        const void *kbuf, const void __user *ubuf)
 180 {
 181         struct pt_regs *regs = task_pt_regs(target);
 182         int ret;
 183
 184         /* Don't let people set SYSCFG (it's at the end of pt_regs) */
 185         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 186                                  regs, 0, PT_SYSCFG);
 187         if (ret < 0)
 188                 return ret;
 189
 190         /* This sucks ... */
 191         target->thread.usp = regs->usp;
 192         /* regs->retx = regs->pc; */
 193
 194         return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 195                                         PT_SYSCFG, -1);
 196 }
 197
 198 /*
 199  * Define the register sets available on the Blackfin under Linux
 200  */
 201 enum bfin_regset {
 202         REGSET_GENERAL,
 203 };
 204
 205 static const struct user_regset bfin_regsets[] = {
 206         [REGSET_GENERAL] = {
 207                 .core_note_type = NT_PRSTATUS,
 208                 .n              = sizeof(struct pt_regs) / sizeof(long),
 209                 .size           = sizeof(long),
 210                 .align          = sizeof(long),
 211                 .get            = genregs_get,
 212                 .set            = genregs_set,
 213         },
 214 };
 215
 216 static const struct user_regset_view user_bfin_native_view = {
 217         .name      = "Blackfin",
 218         .e_machine = EM_BLACKFIN,
 219         .regsets   = bfin_regsets,
 220         .n         = ARRAY_SIZE(bfin_regsets),
 221 };
 222
 223 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 224 {
 225         return &user_bfin_native_view;
 226 }
 227
 228 void user_enable_single_step(struct task_struct *child)
 229 {
 230         struct pt_regs *regs = task_pt_regs(child);
 231         regs->syscfg |= SYSCFG_SSSTEP;
 232
 233         set_tsk_thread_flag(child, TIF_SINGLESTEP);
 234 }
 235
 236 void user_disable_single_step(struct task_struct *child)
 237 {
 238         struct pt_regs *regs = task_pt_regs(child);
 239         regs->syscfg &= ~SYSCFG_SSSTEP;
 240
 241         clear_tsk_thread_flag(child, TIF_SINGLESTEP);
 242 }
 243
 244 long arch_ptrace(struct task_struct *child, long request,
 245                  unsigned long addr, unsigned long data)
 246 {
 247         int ret;
 248         unsigned long __user *datap = (unsigned long __user *)data;
 249         void *paddr = (void *)addr;
 250
 251         switch (request) {
 252                 /* when I and D space are separate, these will need to be fixed. */
 253         case PTRACE_PEEKDATA:
 254                 pr_debug("ptrace: PEEKDATA\n");
 255                 /* fall through */
 256         case PTRACE_PEEKTEXT:   /* read word at location addr. */
 257                 {
 258                         unsigned long tmp = 0;
 259                         int copied = 0, to_copy = sizeof(tmp);
 260
 261                         ret = -EIO;
 262                         pr_debug("ptrace: PEEKTEXT at addr 0x%08lx + %i\n", addr, to_copy);
 263                         if (is_user_addr_valid(child, addr, to_copy) < 0)
 264                                 break;
 265                         pr_debug("ptrace: user address is valid\n");
 266
 267                         switch (bfin_mem_access_type(addr, to_copy)) {
 268                         case BFIN_MEM_ACCESS_CORE:
 269                         case BFIN_MEM_ACCESS_CORE_ONLY:
 270                                 copied = access_process_vm(child, addr, &tmp,
 271                                                            to_copy, 0);
 272                                 if (copied)
 273                                         break;
 274
 275                                 /* hrm, why didn't that work ... maybe no mapping */
 276                                 if (addr >= FIXED_CODE_START &&
 277                                     addr + to_copy <= FIXED_CODE_END) {
 278                                         copy_from_user_page(0, 0, 0, &tmp, paddr, to_copy);
 279                                         copied = to_copy;
 280                                 } else if (addr >= BOOT_ROM_START) {
 281                                         memcpy(&tmp, paddr, to_copy);
 282                                         copied = to_copy;
 283                                 }
 284
 285                                 break;
 286                         case BFIN_MEM_ACCESS_DMA:
 287                                 if (safe_dma_memcpy(&tmp, paddr, to_copy))
 288                                         copied = to_copy;
 289                                 break;
 290                         case BFIN_MEM_ACCESS_ITEST:
 291                                 if (isram_memcpy(&tmp, paddr, to_copy))
 292                                         copied = to_copy;
 293                                 break;
 294                         default:
 295                                 copied = 0;
 296                                 break;
 297                         }
 298
 299                         pr_debug("ptrace: copied size %d [0x%08lx]\n", copied, tmp);
 300                         if (copied == to_copy)
 301                                 ret = put_user(tmp, datap);
 302                         break;
 303                 }
 304
 305                 /* when I and D space are separate, this will have to be fixed. */
 306         case PTRACE_POKEDATA:
 307                 pr_debug("ptrace: PTRACE_PEEKDATA\n");
 308                 /* fall through */
 309         case PTRACE_POKETEXT:   /* write the word at location addr. */
 310                 {
 311                         int copied = 0, to_copy = sizeof(data);
 312
 313                         ret = -EIO;
 314                         pr_debug("ptrace: POKETEXT at addr 0x%08lx + %i bytes %lx\n",
 315                                  addr, to_copy, data);
 316                         if (is_user_addr_valid(child, addr, to_copy) < 0)
 317                                 break;
 318                         pr_debug("ptrace: user address is valid\n");
 319
 320                         switch (bfin_mem_access_type(addr, to_copy)) {
 321                         case BFIN_MEM_ACCESS_CORE:
 322                         case BFIN_MEM_ACCESS_CORE_ONLY:
 323                                 copied = access_process_vm(child, addr, &data,
 324                                                            to_copy, 1);
 325                                 break;
 326                         case BFIN_MEM_ACCESS_DMA:
 327                                 if (safe_dma_memcpy(paddr, &data, to_copy))
 328                                         copied = to_copy;
 329                                 break;
 330                         case BFIN_MEM_ACCESS_ITEST:
 331                                 if (isram_memcpy(paddr, &data, to_copy))
 332                                         copied = to_copy;
 333                                 break;
 334                         default:
 335                                 copied = 0;
 336                                 break;
 337                         }
 338
 339                         pr_debug("ptrace: copied size %d\n", copied);
 340                         if (copied == to_copy)
 341                                 ret = 0;
 342                         break;
 343                 }
 344
 345         case PTRACE_PEEKUSR:
 346                 switch (addr) {
 347 #ifdef CONFIG_BINFMT_ELF_FDPIC  /* backwards compat */
 348                 case PT_FDPIC_EXEC:
 349                         request = PTRACE_GETFDPIC;
 350                         addr = PTRACE_GETFDPIC_EXEC;
 351                         goto case_default;
 352                 case PT_FDPIC_INTERP:
 353                         request = PTRACE_GETFDPIC;
 354                         addr = PTRACE_GETFDPIC_INTERP;
 355                         goto case_default;
 356 #endif
 357                 default:
 358                         ret = get_reg(child, addr, datap);
 359                 }
 360                 pr_debug("ptrace: PEEKUSR reg %li with %#lx = %i\n", addr, data, ret);
 361                 break;
 362
 363         case PTRACE_POKEUSR:
 364                 ret = put_reg(child, addr, data);
 365                 pr_debug("ptrace: POKEUSR reg %li with %li = %i\n", addr, data, ret);
 366                 break;
 367
 368         case PTRACE_GETREGS:
 369                 pr_debug("ptrace: PTRACE_GETREGS\n");
 370                 return copy_regset_to_user(child, &user_bfin_native_view,
 371                                            REGSET_GENERAL,
 372                                            0, sizeof(struct pt_regs),
 373                                            datap);
 374
 375         case PTRACE_SETREGS:
 376                 pr_debug("ptrace: PTRACE_SETREGS\n");
 377                 return copy_regset_from_user(child, &user_bfin_native_view,
 378                                              REGSET_GENERAL,
 379                                              0, sizeof(struct pt_regs),
 380                                              datap);
 381
 382         case_default:
 383         default:
 384                 ret = ptrace_request(child, request, addr, data);
 385                 break;
 386         }
 387
 388         return ret;
 389 }
 390
 391 asmlinkage int syscall_trace_enter(struct pt_regs *regs)
 392 {
 393         int ret = 0;
 394
 395         if (test_thread_flag(TIF_SYSCALL_TRACE))
 396                 ret = tracehook_report_syscall_entry(regs);
 397
 398         return ret;
 399 }
 400
 401 asmlinkage void syscall_trace_leave(struct pt_regs *regs)
 402 {
 403         int step;
 404
 405         step = test_thread_flag(TIF_SINGLESTEP);
 406         if (step || test_thread_flag(TIF_SYSCALL_TRACE))
 407                 tracehook_report_syscall_exit(regs, step);
 408 }