LXR linux/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 2004-2009 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/errno.h>
  13#include <linux/ptrace.h>
  14#include <linux/user.h>
  15#include <linux/signal.h>
  16#include <linux/uaccess.h>
  17
  18#include <asm/page.h>
  19#include <asm/pgtable.h>
  20#include <asm/system.h>
  21#include <asm/processor.h>
  22#include <asm/asm-offsets.h>
  23#include <asm/dma.h>
  24#include <asm/fixed_code.h>
  25#include <asm/cacheflush.h>
  26#include <asm/mem_map.h>
  27
  28#define TEXT_OFFSET 0
  29/*
  30 * does not yet catch signals sent when the child dies.
  31 * in exit.c or in signal.c.
  32 */
  33
  34/* determines which bits in the SYSCFG reg the user has access to. */
  35/* 1 = access 0 = no access */
  36#define SYSCFG_MASK 0x0007      /* SYSCFG reg */
  37/* sets the trace bits. */
  38#define TRACE_BITS 0x0001
  39
  40/* Find the stack offset for a register, relative to thread.esp0. */
  41#define PT_REG(reg)     ((long)&((struct pt_regs *)0)->reg)
  42
  43/*
  44 * Get the address of the live pt_regs for the specified task.
  45 * These are saved onto the top kernel stack when the process
  46 * is not running.
  47 *
  48 * Note: if a user thread is execve'd from kernel space, the
  49 * kernel stack will not be empty on entry to the kernel, so
  50 * ptracing these tasks will fail.
  51 */
  52static inline struct pt_regs *get_user_regs(struct task_struct *task)
  53{
  54        return (struct pt_regs *)
  55            ((unsigned long)task_stack_page(task) +
  56             (THREAD_SIZE - sizeof(struct pt_regs)));
  57}
  58
  59/*
  60 * Get all user integer registers.
  61 */
  62static inline int ptrace_getregs(struct task_struct *tsk, void __user *uregs)
  63{
  64        struct pt_regs regs;
  65        memcpy(&regs, get_user_regs(tsk), sizeof(regs));
  66        regs.usp = tsk->thread.usp;
  67        return copy_to_user(uregs, &regs, sizeof(struct pt_regs)) ? -EFAULT : 0;
  68}
  69
  70/* Mapping from PT_xxx to the stack offset at which the register is
  71 * saved.  Notice that usp has no stack-slot and needs to be treated
  72 * specially (see get_reg/put_reg below).
  73 */
  74
  75/*
  76 * Get contents of register REGNO in task TASK.
  77 */
  78static inline long get_reg(struct task_struct *task, int regno)
  79{
  80        unsigned char *reg_ptr;
  81
  82        struct pt_regs *regs =
  83            (struct pt_regs *)((unsigned long)task_stack_page(task) +
  84                               (THREAD_SIZE - sizeof(struct pt_regs)));
  85        reg_ptr = (char *)regs;
  86
  87        switch (regno) {
  88        case PT_USP:
  89                return task->thread.usp;
  90        default:
  91                if (regno <= 216)
  92                        return *(long *)(reg_ptr + regno);
  93        }
  94        /* slight mystery ... never seems to come here but kernel misbehaves without this code! */
  95
  96        printk(KERN_WARNING "Request to get for unknown register %d\n", regno);
  97        return 0;
  98}
  99
 100/*
 101 * Write contents of register REGNO in task TASK.
 102 */
 103static inline int
 104put_reg(struct task_struct *task, int regno, unsigned long data)
 105{
 106        char *reg_ptr;
 107
 108        struct pt_regs *regs =
 109            (struct pt_regs *)((unsigned long)task_stack_page(task) +
 110                               (THREAD_SIZE - sizeof(struct pt_regs)));
 111        reg_ptr = (char *)regs;
 112
 113        switch (regno) {
 114        case PT_PC:
 115                /*********************************************************************/
 116                /* At this point the kernel is most likely in exception.             */
 117                /* The RETX register will be used to populate the pc of the process. */
 118                /*********************************************************************/
 119                regs->retx = data;
 120                regs->pc = data;
 121                break;
 122        case PT_RETX:
 123                break;          /* regs->retx = data; break; */
 124        case PT_USP:
 125                regs->usp = data;
 126                task->thread.usp = data;
 127                break;
 128        default:
 129                if (regno <= 216)
 130                        *(long *)(reg_ptr + regno) = data;
 131        }
 132        return 0;
 133}
 134
 135/*
 136 * check that an address falls within the bounds of the target process's memory mappings
 137 */
 138static inline int is_user_addr_valid(struct task_struct *child,
 139                                     unsigned long start, unsigned long len)
 140{
 141        struct vm_area_struct *vma;
 142        struct sram_list_struct *sraml;
 143
 144        /* overflow */
 145        if (start + len < start)
 146                return -EIO;
 147
 148        vma = find_vma(child->mm, start);
 149        if (vma && start >= vma->vm_start && start + len <= vma->vm_end)
 150                        return 0;
 151
 152        for (sraml = child->mm->context.sram_list; sraml; sraml = sraml->next)
 153                if (start >= (unsigned long)sraml->addr
 154                    && start + len < (unsigned long)sraml->addr + sraml->length)
 155                        return 0;
 156
 157        if (start >= FIXED_CODE_START && start + len < FIXED_CODE_END)
 158                return 0;
 159
 160        return -EIO;
 161}
 162
 163void ptrace_enable(struct task_struct *child)
 164{
 165        unsigned long tmp;
 166        tmp = get_reg(child, PT_SYSCFG) | (TRACE_BITS);
 167        put_reg(child, PT_SYSCFG, tmp);
 168}
 169
 170/*
 171 * Called by kernel/ptrace.c when detaching..
 172 *
 173 * Make sure the single step bit is not set.
 174 */
 175void ptrace_disable(struct task_struct *child)
 176{
 177        unsigned long tmp;
 178        /* make sure the single step bit is not set. */
 179        tmp = get_reg(child, PT_SYSCFG) & ~TRACE_BITS;
 180        put_reg(child, PT_SYSCFG, tmp);
 181}
 182
 183long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 184{
 185        int ret;
 186        unsigned long __user *datap = (unsigned long __user *)data;
 187        void *paddr = (void *)addr;
 188
 189        switch (request) {
 190                /* when I and D space are separate, these will need to be fixed. */
 191        case PTRACE_PEEKDATA:
 192                pr_debug("ptrace: PEEKDATA\n");
 193                /* fall through */
 194        case PTRACE_PEEKTEXT:   /* read word at location addr. */
 195                {
 196                        unsigned long tmp = 0;
 197                        int copied = 0, to_copy = sizeof(tmp);
 198
 199                        ret = -EIO;
 200                        pr_debug("ptrace: PEEKTEXT at addr 0x%08lx + %i\n", addr, to_copy);
 201                        if (is_user_addr_valid(child, addr, to_copy) < 0)
 202                                break;
 203                        pr_debug("ptrace: user address is valid\n");
 204
 205                        switch (bfin_mem_access_type(addr, to_copy)) {
 206                        case BFIN_MEM_ACCESS_CORE:
 207                        case BFIN_MEM_ACCESS_CORE_ONLY:
 208                                copied = access_process_vm(child, addr, &tmp,
 209                                                           to_copy, 0);
 210                                if (copied)
 211                                        break;
 212
 213                                /* hrm, why didn't that work ... maybe no mapping */
 214                                if (addr >= FIXED_CODE_START &&
 215                                    addr + to_copy <= FIXED_CODE_END) {
 216                                        copy_from_user_page(0, 0, 0, &tmp, paddr, to_copy);
 217                                        copied = to_copy;
 218                                } else if (addr >= BOOT_ROM_START) {
 219                                        memcpy(&tmp, paddr, to_copy);
 220                                        copied = to_copy;
 221                                }
 222
 223                                break;
 224                        case BFIN_MEM_ACCESS_DMA:
 225                                if (safe_dma_memcpy(&tmp, paddr, to_copy))
 226                                        copied = to_copy;
 227                                break;
 228                        case BFIN_MEM_ACCESS_ITEST:
 229                                if (isram_memcpy(&tmp, paddr, to_copy))
 230                                        copied = to_copy;
 231                                break;
 232                        default:
 233                                copied = 0;
 234                                break;
 235                        }
 236
 237                        pr_debug("ptrace: copied size %d [0x%08lx]\n", copied, tmp);
 238                        if (copied == to_copy)
 239                                ret = put_user(tmp, datap);
 240                        break;
 241                }
 242
 243                /* read the word at location addr in the USER area. */
 244        case PTRACE_PEEKUSR:
 245                {
 246                        unsigned long tmp;
 247                        ret = -EIO;
 248                        tmp = 0;
 249                        if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
 250                                printk(KERN_WARNING "ptrace error : PEEKUSR : temporarily returning "
 251                                                    "0 - %x sizeof(pt_regs) is %lx\n",
 252                                     (int)addr, sizeof(struct pt_regs));
 253                                break;
 254                        }
 255                        if (addr == sizeof(struct pt_regs)) {
 256                                /* PT_TEXT_ADDR */
 257                                tmp = child->mm->start_code + TEXT_OFFSET;
 258                        } else if (addr == (sizeof(struct pt_regs) + 4)) {
 259                                /* PT_TEXT_END_ADDR */
 260                                tmp = child->mm->end_code;
 261                        } else if (addr == (sizeof(struct pt_regs) + 8)) {
 262                                /* PT_DATA_ADDR */
 263                                tmp = child->mm->start_data;
 264#ifdef CONFIG_BINFMT_ELF_FDPIC
 265                        } else if (addr == (sizeof(struct pt_regs) + 12)) {
 266                                goto case_PTRACE_GETFDPIC_EXEC;
 267                        } else if (addr == (sizeof(struct pt_regs) + 16)) {
 268                                goto case_PTRACE_GETFDPIC_INTERP;
 269#endif
 270                        } else {
 271                                tmp = get_reg(child, addr);
 272                        }
 273                        ret = put_user(tmp, datap);
 274                        break;
 275                }
 276
 277#ifdef CONFIG_BINFMT_ELF_FDPIC
 278        case PTRACE_GETFDPIC: {
 279                unsigned long tmp = 0;
 280
 281                switch (addr) {
 282                case_PTRACE_GETFDPIC_EXEC:
 283                case PTRACE_GETFDPIC_EXEC:
 284                        tmp = child->mm->context.exec_fdpic_loadmap;
 285                        break;
 286                case_PTRACE_GETFDPIC_INTERP:
 287                case PTRACE_GETFDPIC_INTERP:
 288                        tmp = child->mm->context.interp_fdpic_loadmap;
 289                        break;
 290                default:
 291                        break;
 292                }
 293
 294                ret = put_user(tmp, datap);
 295                break;
 296        }
 297#endif
 298
 299                /* when I and D space are separate, this will have to be fixed. */
 300        case PTRACE_POKEDATA:
 301                pr_debug("ptrace: PTRACE_PEEKDATA\n");
 302                /* fall through */
 303        case PTRACE_POKETEXT:   /* write the word at location addr. */
 304                {
 305                        int copied = 0, to_copy = sizeof(data);
 306
 307                        ret = -EIO;
 308                        pr_debug("ptrace: POKETEXT at addr 0x%08lx + %i bytes %lx\n",
 309                                 addr, to_copy, data);
 310                        if (is_user_addr_valid(child, addr, to_copy) < 0)
 311                                break;
 312                        pr_debug("ptrace: user address is valid\n");
 313
 314                        switch (bfin_mem_access_type(addr, to_copy)) {
 315                        case BFIN_MEM_ACCESS_CORE:
 316                        case BFIN_MEM_ACCESS_CORE_ONLY:
 317                                copied = access_process_vm(child, addr, &data,
 318                                                           to_copy, 1);
 319                                if (copied)
 320                                        break;
 321
 322                                /* hrm, why didn't that work ... maybe no mapping */
 323                                if (addr >= FIXED_CODE_START &&
 324                                    addr + to_copy <= FIXED_CODE_END) {
 325                                        copy_to_user_page(0, 0, 0, paddr, &data, to_copy);
 326                                        copied = to_copy;
 327                                } else if (addr >= BOOT_ROM_START) {
 328                                        memcpy(paddr, &data, to_copy);
 329                                        copied = to_copy;
 330                                }
 331
 332                                break;
 333                        case BFIN_MEM_ACCESS_DMA:
 334                                if (safe_dma_memcpy(paddr, &data, to_copy))
 335                                        copied = to_copy;
 336                                break;
 337                        case BFIN_MEM_ACCESS_ITEST:
 338                                if (isram_memcpy(paddr, &data, to_copy))
 339                                        copied = to_copy;
 340                                break;
 341                        default:
 342                                copied = 0;
 343                                break;
 344                        }
 345
 346                        pr_debug("ptrace: copied size %d\n", copied);
 347                        if (copied == to_copy)
 348                                ret = 0;
 349                        break;
 350                }
 351
 352        case PTRACE_POKEUSR:    /* write the word at location addr in the USER area */
 353                ret = -EIO;
 354                if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
 355                        printk(KERN_WARNING "ptrace error : POKEUSR: temporarily returning 0\n");
 356                        break;
 357                }
 358
 359                if (addr >= (sizeof(struct pt_regs))) {
 360                        ret = 0;
 361                        break;
 362                }
 363                if (addr == PT_SYSCFG) {
 364                        data &= SYSCFG_MASK;
 365                        data |= get_reg(child, PT_SYSCFG);
 366                }
 367                ret = put_reg(child, addr, data);
 368                break;
 369
 370        case PTRACE_SYSCALL:    /* continue and stop at next (return from) syscall */
 371        case PTRACE_CONT:       /* restart after signal. */
 372                pr_debug("ptrace: syscall/cont\n");
 373
 374                ret = -EIO;
 375                if (!valid_signal(data))
 376                        break;
 377                if (request == PTRACE_SYSCALL)
 378                        set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 379                else
 380                        clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 381                child->exit_code = data;
 382                ptrace_disable(child);
 383                pr_debug("ptrace: before wake_up_process\n");
 384                wake_up_process(child);
 385                ret = 0;
 386                break;
 387
 388        /*
 389         * make the child exit.  Best I can do is send it a sigkill.
 390         * perhaps it should be put in the status that it wants to
 391         * exit.
 392         */
 393        case PTRACE_KILL:
 394                ret = 0;
 395                if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 396                        break;
 397                child->exit_code = SIGKILL;
 398                ptrace_disable(child);
 399                wake_up_process(child);
 400                break;
 401
 402        case PTRACE_SINGLESTEP: /* set the trap flag. */
 403                pr_debug("ptrace: single step\n");
 404                ret = -EIO;
 405                if (!valid_signal(data))
 406                        break;
 407                clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 408                ptrace_enable(child);
 409                child->exit_code = data;
 410                wake_up_process(child);
 411                ret = 0;
 412                break;
 413
 414        case PTRACE_GETREGS:
 415                /* Get all gp regs from the child. */
 416                ret = ptrace_getregs(child, datap);
 417                break;
 418
 419        case PTRACE_SETREGS:
 420                printk(KERN_WARNING "ptrace: SETREGS: **** NOT IMPLEMENTED ***\n");
 421                /* Set all gp regs in the child. */
 422                ret = 0;
 423                break;
 424
 425        default:
 426                ret = ptrace_request(child, request, addr, data);
 427                break;
 428        }
 429
 430        return ret;
 431}
 432
 433asmlinkage void syscall_trace(void)
 434{
 435        if (!test_thread_flag(TIF_SYSCALL_TRACE))
 436                return;
 437
 438        if (!(current->ptrace & PT_PTRACED))
 439                return;
 440
 441        /* the 0x80 provides a way for the tracing parent to distinguish
 442         * between a syscall stop and SIGTRAP delivery
 443         */
 444        ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 445                                 ? 0x80 : 0));
 446
 447        /*
 448         * this isn't the same as continuing with a signal, but it will do
 449         * for normal use.  strace only continues with a signal if the
 450         * stopping signal is not SIGTRAP.  -brl
 451         */
 452        if (current->exit_code) {
 453                send_sig(current->exit_code, current, 1);
 454                current->exit_code = 0;
 455        }
 456}
 457