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         bool valid;
 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         down_read(&child->mm->mmap_sem);
 129         vma = find_vma(child->mm, start);
 130         valid = vma && start >= vma->vm_start && start + len <= vma->vm_end;
 131         up_read(&child->mm->mmap_sem);
 132         if (valid)
 133                 return 0;
 134
 135         for (sraml = child->mm->context.sram_list; sraml; sraml = sraml->next)
 136                 if (start >= (unsigned long)sraml->addr
 137                     && start + len < (unsigned long)sraml->addr + sraml->length)
 138                         return 0;
 139
 140         if (start >= FIXED_CODE_START && start + len < FIXED_CODE_END)
 141                 return 0;
 142
 143 #ifdef CONFIG_APP_STACK_L1
 144         if (child->mm->context.l1_stack_save)
 145                 if (start >= (unsigned long)l1_stack_base &&
 146                         start + len < (unsigned long)l1_stack_base + l1_stack_len)
 147                         return 0;
 148 #endif
 149
 150         return -EIO;
 151 }
 152
 153 /*
 154  * retrieve the contents of Blackfin userspace general registers
 155  */
 156 static int genregs_get(struct task_struct *target,
 157                        const struct user_regset *regset,
 158                        unsigned int pos, unsigned int count,
 159                        void *kbuf, void __user *ubuf)
 160 {
 161         struct pt_regs *regs = task_pt_regs(target);
 162         int ret;
 163
 164         /* This sucks ... */
 165         regs->usp = target->thread.usp;
 166
 167         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 168                                   regs, 0, sizeof(*regs));
 169         if (ret < 0)
 170                 return ret;
 171
 172         return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 173                                         sizeof(*regs), -1);
 174 }
 175
 176 /*
 177  * update the contents of the Blackfin userspace general registers
 178  */
 179 static int genregs_set(struct task_struct *target,
 180                        const struct user_regset *regset,
 181                        unsigned int pos, unsigned int count,
 182                        const void *kbuf, const void __user *ubuf)
 183 {
 184         struct pt_regs *regs = task_pt_regs(target);
 185         int ret;
 186
 187         /* Don't let people set SYSCFG (it's at the end of pt_regs) */
 188         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 189                                  regs, 0, PT_SYSCFG);
 190         if (ret < 0)
 191                 return ret;
 192
 193         /* This sucks ... */
 194         target->thread.usp = regs->usp;
 195         /* regs->retx = regs->pc; */
 196
 197         return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 198                                         PT_SYSCFG, -1);
 199 }
 200
 201 /*
 202  * Define the register sets available on the Blackfin under Linux
 203  */
 204 enum bfin_regset {
 205         REGSET_GENERAL,
 206 };
 207
 208 static const struct user_regset bfin_regsets[] = {
 209         [REGSET_GENERAL] = {
 210                 .core_note_type = NT_PRSTATUS,
 211                 .n              = sizeof(struct pt_regs) / sizeof(long),
 212                 .size           = sizeof(long),
 213                 .align          = sizeof(long),
 214                 .get            = genregs_get,
 215                 .set            = genregs_set,
 216         },
 217 };
 218
 219 static const struct user_regset_view user_bfin_native_view = {
 220         .name      = "Blackfin",
 221         .e_machine = EM_BLACKFIN,
 222         .regsets   = bfin_regsets,
 223         .n         = ARRAY_SIZE(bfin_regsets),
 224 };
 225
 226 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 227 {
 228         return &user_bfin_native_view;
 229 }
 230
 231 void user_enable_single_step(struct task_struct *child)
 232 {
 233         struct pt_regs *regs = task_pt_regs(child);
 234         regs->syscfg |= SYSCFG_SSSTEP;
 235
 236         set_tsk_thread_flag(child, TIF_SINGLESTEP);
 237 }
 238
 239 void user_disable_single_step(struct task_struct *child)
 240 {
 241         struct pt_regs *regs = task_pt_regs(child);
 242         regs->syscfg &= ~SYSCFG_SSSTEP;
 243
 244         clear_tsk_thread_flag(child, TIF_SINGLESTEP);
 245 }
 246
 247 long arch_ptrace(struct task_struct *child, long request,
 248                  unsigned long addr, unsigned long data)
 249 {
 250         int ret;
 251         unsigned long __user *datap = (unsigned long __user *)data;
 252         void *paddr = (void *)addr;
 253
 254         switch (request) {
 255                 /* when I and D space are separate, these will need to be fixed. */
 256         case PTRACE_PEEKDATA:
 257                 pr_debug("ptrace: PEEKDATA\n");
 258                 /* fall through */
 259         case PTRACE_PEEKTEXT:   /* read word at location addr. */
 260                 {
 261                         unsigned long tmp = 0;
 262                         int copied = 0, to_copy = sizeof(tmp);
 263
 264                         ret = -EIO;
 265                         pr_debug("ptrace: PEEKTEXT at addr 0x%08lx + %i\n", addr, to_copy);
 266                         if (is_user_addr_valid(child, addr, to_copy) < 0)
 267                                 break;
 268                         pr_debug("ptrace: user address is valid\n");
 269
 270                         switch (bfin_mem_access_type(addr, to_copy)) {
 271                         case BFIN_MEM_ACCESS_CORE:
 272                         case BFIN_MEM_ACCESS_CORE_ONLY:
 273                                 copied = ptrace_access_vm(child, addr, &tmp,
 274                                                            to_copy, FOLL_FORCE);
 275                                 if (copied)
 276                                         break;
 277
 278                                 /* hrm, why didn't that work ... maybe no mapping */
 279                                 if (addr >= FIXED_CODE_START &&
 280                                     addr + to_copy <= FIXED_CODE_END) {
 281                                         copy_from_user_page(0, 0, 0, &tmp, paddr, to_copy);
 282                                         copied = to_copy;
 283                                 } else if (addr >= BOOT_ROM_START) {
 284                                         memcpy(&tmp, paddr, to_copy);
 285                                         copied = to_copy;
 286                                 }
 287
 288                                 break;
 289                         case BFIN_MEM_ACCESS_DMA:
 290                                 if (safe_dma_memcpy(&tmp, paddr, to_copy))
 291                                         copied = to_copy;
 292                                 break;
 293                         case BFIN_MEM_ACCESS_ITEST:
 294                                 if (isram_memcpy(&tmp, paddr, to_copy))
 295                                         copied = to_copy;
 296                                 break;
 297                         default:
 298                                 copied = 0;
 299                                 break;
 300                         }
 301
 302                         pr_debug("ptrace: copied size %d [0x%08lx]\n", copied, tmp);
 303                         if (copied == to_copy)
 304                                 ret = put_user(tmp, datap);
 305                         break;
 306                 }
 307
 308                 /* when I and D space are separate, this will have to be fixed. */
 309         case PTRACE_POKEDATA:
 310                 pr_debug("ptrace: PTRACE_PEEKDATA\n");
 311                 /* fall through */
 312         case PTRACE_POKETEXT:   /* write the word at location addr. */
 313                 {
 314                         int copied = 0, to_copy = sizeof(data);
 315
 316                         ret = -EIO;
 317                         pr_debug("ptrace: POKETEXT at addr 0x%08lx + %i bytes %lx\n",
 318                                  addr, to_copy, data);
 319                         if (is_user_addr_valid(child, addr, to_copy) < 0)
 320                                 break;
 321                         pr_debug("ptrace: user address is valid\n");
 322
 323                         switch (bfin_mem_access_type(addr, to_copy)) {
 324                         case BFIN_MEM_ACCESS_CORE:
 325                         case BFIN_MEM_ACCESS_CORE_ONLY:
 326                                 copied = ptrace_access_vm(child, addr, &data,
 327                                                            to_copy,
 328                                                            FOLL_FORCE | FOLL_WRITE);
 329                                 break;
 330                         case BFIN_MEM_ACCESS_DMA:
 331                                 if (safe_dma_memcpy(paddr, &data, to_copy))
 332                                         copied = to_copy;
 333                                 break;
 334                         case BFIN_MEM_ACCESS_ITEST:
 335                                 if (isram_memcpy(paddr, &data, to_copy))
 336                                         copied = to_copy;
 337                                 break;
 338                         default:
 339                                 copied = 0;
 340                                 break;
 341                         }
 342
 343                         pr_debug("ptrace: copied size %d\n", copied);
 344                         if (copied == to_copy)
 345                                 ret = 0;
 346                         break;
 347                 }
 348
 349         case PTRACE_PEEKUSR:
 350                 switch (addr) {
 351 #ifdef CONFIG_BINFMT_ELF_FDPIC  /* backwards compat */
 352                 case PT_FDPIC_EXEC:
 353                         request = PTRACE_GETFDPIC;
 354                         addr = PTRACE_GETFDPIC_EXEC;
 355                         goto case_default;
 356                 case PT_FDPIC_INTERP:
 357                         request = PTRACE_GETFDPIC;
 358                         addr = PTRACE_GETFDPIC_INTERP;
 359                         goto case_default;
 360 #endif
 361                 default:
 362                         ret = get_reg(child, addr, datap);
 363                 }
 364                 pr_debug("ptrace: PEEKUSR reg %li with %#lx = %i\n", addr, data, ret);
 365                 break;
 366
 367         case PTRACE_POKEUSR:
 368                 ret = put_reg(child, addr, data);
 369                 pr_debug("ptrace: POKEUSR reg %li with %li = %i\n", addr, data, ret);
 370                 break;
 371
 372         case PTRACE_GETREGS:
 373                 pr_debug("ptrace: PTRACE_GETREGS\n");
 374                 return copy_regset_to_user(child, &user_bfin_native_view,
 375                                            REGSET_GENERAL,
 376                                            0, sizeof(struct pt_regs),
 377                                            datap);
 378
 379         case PTRACE_SETREGS:
 380                 pr_debug("ptrace: PTRACE_SETREGS\n");
 381                 return copy_regset_from_user(child, &user_bfin_native_view,
 382                                              REGSET_GENERAL,
 383                                              0, sizeof(struct pt_regs),
 384                                              datap);
 385
 386         case_default:
 387         default:
 388                 ret = ptrace_request(child, request, addr, data);
 389                 break;
 390         }
 391
 392         return ret;
 393 }
 394
 395 asmlinkage int syscall_trace_enter(struct pt_regs *regs)
 396 {
 397         int ret = 0;
 398
 399         if (test_thread_flag(TIF_SYSCALL_TRACE))
 400                 ret = tracehook_report_syscall_entry(regs);
 401
 402         return ret;
 403 }
 404
 405 asmlinkage void syscall_trace_leave(struct pt_regs *regs)
 406 {
 407         int step;
 408
 409         step = test_thread_flag(TIF_SINGLESTEP);
 410         if (step || test_thread_flag(TIF_SYSCALL_TRACE))
 411                 tracehook_report_syscall_exit(regs, step);
 412 }