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