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