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/sched/task_stack.h>
  11 #include <linux/mm.h>
  12 #include <linux/smp.h>
  13 #include <linux/elf.h>
  14 #include <linux/errno.h>
  15 #include <linux/ptrace.h>
  16 #include <linux/user.h>
  17 #include <linux/regset.h>
  18 #include <linux/signal.h>
  19 #include <linux/tracehook.h>
  20 #include <linux/uaccess.h>
  21
  22 #include <asm/page.h>
  23 #include <asm/pgtable.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         bool valid;
 122         struct vm_area_struct *vma;
 123         struct sram_list_struct *sraml;
 124
 125         /* overflow */
 126         if (start + len < start)
 127                 return -EIO;
 128
 129         down_read(&child->mm->mmap_sem);
 130         vma = find_vma(child->mm, start);
 131         valid = vma && start >= vma->vm_start && start + len <= vma->vm_end;
 132         up_read(&child->mm->mmap_sem);
 133         if (valid)
 134                 return 0;
 135
 136         for (sraml = child->mm->context.sram_list; sraml; sraml = sraml->next)
 137                 if (start >= (unsigned long)sraml->addr
 138                     && start + len < (unsigned long)sraml->addr + sraml->length)
 139                         return 0;
 140
 141         if (start >= FIXED_CODE_START && start + len < FIXED_CODE_END)
 142                 return 0;
 143
 144 #ifdef CONFIG_APP_STACK_L1
 145         if (child->mm->context.l1_stack_save)
 146                 if (start >= (unsigned long)l1_stack_base &&
 147                         start + len < (unsigned long)l1_stack_base + l1_stack_len)
 148                         return 0;
 149 #endif
 150
 151         return -EIO;
 152 }
 153
 154 /*
 155  * retrieve the contents of Blackfin userspace general registers
 156  */
 157 static int genregs_get(struct task_struct *target,
 158                        const struct user_regset *regset,
 159                        unsigned int pos, unsigned int count,
 160                        void *kbuf, void __user *ubuf)
 161 {
 162         struct pt_regs *regs = task_pt_regs(target);
 163         int ret;
 164
 165         /* This sucks ... */
 166         regs->usp = target->thread.usp;
 167
 168         ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 169                                   regs, 0, sizeof(*regs));
 170         if (ret < 0)
 171                 return ret;
 172
 173         return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
 174                                         sizeof(*regs), -1);
 175 }
 176
 177 /*
 178  * update the contents of the Blackfin userspace general registers
 179  */
 180 static int genregs_set(struct task_struct *target,
 181                        const struct user_regset *regset,
 182                        unsigned int pos, unsigned int count,
 183                        const void *kbuf, const void __user *ubuf)
 184 {
 185         struct pt_regs *regs = task_pt_regs(target);
 186         int ret;
 187
 188         /* Don't let people set SYSCFG (it's at the end of pt_regs) */
 189         ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 190                                  regs, 0, PT_SYSCFG);
 191         if (ret < 0)
 192                 return ret;
 193
 194         /* This sucks ... */
 195         target->thread.usp = regs->usp;
 196         /* regs->retx = regs->pc; */
 197
 198         return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
 199                                         PT_SYSCFG, -1);
 200 }
 201
 202 /*
 203  * Define the register sets available on the Blackfin under Linux
 204  */
 205 enum bfin_regset {
 206         REGSET_GENERAL,
 207 };
 208
 209 static const struct user_regset bfin_regsets[] = {
 210         [REGSET_GENERAL] = {
 211                 .core_note_type = NT_PRSTATUS,
 212                 .n              = sizeof(struct pt_regs) / sizeof(long),
 213                 .size           = sizeof(long),
 214                 .align          = sizeof(long),
 215                 .get            = genregs_get,
 216                 .set            = genregs_set,
 217         },
 218 };
 219
 220 static const struct user_regset_view user_bfin_native_view = {
 221         .name      = "Blackfin",
 222         .e_machine = EM_BLACKFIN,
 223         .regsets   = bfin_regsets,
 224         .n         = ARRAY_SIZE(bfin_regsets),
 225 };
 226
 227 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 228 {
 229         return &user_bfin_native_view;
 230 }
 231
 232 void user_enable_single_step(struct task_struct *child)
 233 {
 234         struct pt_regs *regs = task_pt_regs(child);
 235         regs->syscfg |= SYSCFG_SSSTEP;
 236
 237         set_tsk_thread_flag(child, TIF_SINGLESTEP);
 238 }
 239
 240 void user_disable_single_step(struct task_struct *child)
 241 {
 242         struct pt_regs *regs = task_pt_regs(child);
 243         regs->syscfg &= ~SYSCFG_SSSTEP;
 244
 245         clear_tsk_thread_flag(child, TIF_SINGLESTEP);
 246 }
 247
 248 long arch_ptrace(struct task_struct *child, long request,
 249                  unsigned long addr, unsigned long data)
 250 {
 251         int ret;
 252         unsigned long __user *datap = (unsigned long __user *)data;
 253         void *paddr = (void *)addr;
 254
 255         switch (request) {
 256                 /* when I and D space are separate, these will need to be fixed. */
 257         case PTRACE_PEEKDATA:
 258                 pr_debug("ptrace: PEEKDATA\n");
 259                 /* fall through */
 260         case PTRACE_PEEKTEXT:   /* read word at location addr. */
 261                 {
 262                         unsigned long tmp = 0;
 263                         int copied = 0, to_copy = sizeof(tmp);
 264
 265                         ret = -EIO;
 266                         pr_debug("ptrace: PEEKTEXT at addr 0x%08lx + %i\n", addr, to_copy);
 267                         if (is_user_addr_valid(child, addr, to_copy) < 0)
 268                                 break;
 269                         pr_debug("ptrace: user address is valid\n");
 270
 271                         switch (bfin_mem_access_type(addr, to_copy)) {
 272                         case BFIN_MEM_ACCESS_CORE:
 273                         case BFIN_MEM_ACCESS_CORE_ONLY:
 274                                 copied = ptrace_access_vm(child, addr, &tmp,
 275                                                            to_copy, FOLL_FORCE);
 276                                 if (copied)
 277                                         break;
 278
 279                                 /* hrm, why didn't that work ... maybe no mapping */
 280                                 if (addr >= FIXED_CODE_START &&
 281                                     addr + to_copy <= FIXED_CODE_END) {
 282                                         copy_from_user_page(0, 0, 0, &tmp, paddr, to_copy);
 283                                         copied = to_copy;
 284                                 } else if (addr >= BOOT_ROM_START) {
 285                                         memcpy(&tmp, paddr, to_copy);
 286                                         copied = to_copy;
 287                                 }
 288
 289                                 break;
 290                         case BFIN_MEM_ACCESS_DMA:
 291                                 if (safe_dma_memcpy(&tmp, paddr, to_copy))
 292                                         copied = to_copy;
 293                                 break;
 294                         case BFIN_MEM_ACCESS_ITEST:
 295                                 if (isram_memcpy(&tmp, paddr, to_copy))
 296                                         copied = to_copy;
 297                                 break;
 298                         default:
 299                                 copied = 0;
 300                                 break;
 301                         }
 302
 303                         pr_debug("ptrace: copied size %d [0x%08lx]\n", copied, tmp);
 304                         if (copied == to_copy)
 305                                 ret = put_user(tmp, datap);
 306                         break;
 307                 }
 308
 309                 /* when I and D space are separate, this will have to be fixed. */
 310         case PTRACE_POKEDATA:
 311                 pr_debug("ptrace: PTRACE_PEEKDATA\n");
 312                 /* fall through */
 313         case PTRACE_POKETEXT:   /* write the word at location addr. */
 314                 {
 315                         int copied = 0, to_copy = sizeof(data);
 316
 317                         ret = -EIO;
 318                         pr_debug("ptrace: POKETEXT at addr 0x%08lx + %i bytes %lx\n",
 319                                  addr, to_copy, data);
 320                         if (is_user_addr_valid(child, addr, to_copy) < 0)
 321                                 break;
 322                         pr_debug("ptrace: user address is valid\n");
 323
 324                         switch (bfin_mem_access_type(addr, to_copy)) {
 325                         case BFIN_MEM_ACCESS_CORE:
 326                         case BFIN_MEM_ACCESS_CORE_ONLY:
 327                                 copied = ptrace_access_vm(child, addr, &data,
 328                                                            to_copy,
 329                                                            FOLL_FORCE | FOLL_WRITE);
 330                                 break;
 331                         case BFIN_MEM_ACCESS_DMA:
 332                                 if (safe_dma_memcpy(paddr, &data, to_copy))
 333                                         copied = to_copy;
 334                                 break;
 335                         case BFIN_MEM_ACCESS_ITEST:
 336                                 if (isram_memcpy(paddr, &data, to_copy))
 337                                         copied = to_copy;
 338                                 break;
 339                         default:
 340                                 copied = 0;
 341                                 break;
 342                         }
 343
 344                         pr_debug("ptrace: copied size %d\n", copied);
 345                         if (copied == to_copy)
 346                                 ret = 0;
 347                         break;
 348                 }
 349
 350         case PTRACE_PEEKUSR:
 351                 switch (addr) {
 352 #ifdef CONFIG_BINFMT_ELF_FDPIC  /* backwards compat */
 353                 case PT_FDPIC_EXEC:
 354                         request = PTRACE_GETFDPIC;
 355                         addr = PTRACE_GETFDPIC_EXEC;
 356                         goto case_default;
 357                 case PT_FDPIC_INTERP:
 358                         request = PTRACE_GETFDPIC;
 359                         addr = PTRACE_GETFDPIC_INTERP;
 360                         goto case_default;
 361 #endif
 362                 default:
 363                         ret = get_reg(child, addr, datap);
 364                 }
 365                 pr_debug("ptrace: PEEKUSR reg %li with %#lx = %i\n", addr, data, ret);
 366                 break;
 367
 368         case PTRACE_POKEUSR:
 369                 ret = put_reg(child, addr, data);
 370                 pr_debug("ptrace: POKEUSR reg %li with %li = %i\n", addr, data, ret);
 371                 break;
 372
 373         case PTRACE_GETREGS:
 374                 pr_debug("ptrace: PTRACE_GETREGS\n");
 375                 return copy_regset_to_user(child, &user_bfin_native_view,
 376                                            REGSET_GENERAL,
 377                                            0, sizeof(struct pt_regs),
 378                                            datap);
 379
 380         case PTRACE_SETREGS:
 381                 pr_debug("ptrace: PTRACE_SETREGS\n");
 382                 return copy_regset_from_user(child, &user_bfin_native_view,
 383                                              REGSET_GENERAL,
 384                                              0, sizeof(struct pt_regs),
 385                                              datap);
 386
 387         case_default:
 388         default:
 389                 ret = ptrace_request(child, request, addr, data);
 390                 break;
 391         }
 392
 393         return ret;
 394 }
 395
 396 asmlinkage int syscall_trace_enter(struct pt_regs *regs)
 397 {
 398         int ret = 0;
 399
 400         if (test_thread_flag(TIF_SYSCALL_TRACE))
 401                 ret = tracehook_report_syscall_entry(regs);
 402
 403         return ret;
 404 }
 405
 406 asmlinkage void syscall_trace_leave(struct pt_regs *regs)
 407 {
 408         int step;
 409
 410         step = test_thread_flag(TIF_SINGLESTEP);
 411         if (step || test_thread_flag(TIF_SYSCALL_TRACE))
 412                 tracehook_report_syscall_exit(regs, step);
 413 }