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 2004-2010 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 */
  40static inline long
  41get_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 */
  77static inline int
  78put_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 */
 118int
 119is_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 */
 157static 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 */
 180static 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 */
 205enum bfin_regset {
 206        REGSET_GENERAL,
 207};
 208
 209static 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
 220static 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
 227const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 228{
 229        return &user_bfin_native_view;
 230}
 231
 232void 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
 240void 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
 248long 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
 396asmlinkage 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
 406asmlinkage 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}
 414