LXR linux/arch/m68k/kernel/ptrace.c

   1/*
   2 *  linux/arch/m68k/kernel/ptrace.c
   3 *
   4 *  Copyright (C) 1994 by Hamish Macdonald
   5 *  Taken from linux/kernel/ptrace.c and modified for M680x0.
   6 *  linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
   7 *
   8 * This file is subject to the terms and conditions of the GNU General
   9 * Public License.  See the file COPYING in the main directory of
  10 * this archive for more details.
  11 */
  12
  13#include <linux/kernel.h>
  14#include <linux/sched.h>
  15#include <linux/sched/task_stack.h>
  16#include <linux/mm.h>
  17#include <linux/smp.h>
  18#include <linux/errno.h>
  19#include <linux/ptrace.h>
  20#include <linux/user.h>
  21#include <linux/signal.h>
  22#include <linux/tracehook.h>
  23
  24#include <linux/uaccess.h>
  25#include <asm/page.h>
  26#include <asm/processor.h>
  27
  28/*
  29 * does not yet catch signals sent when the child dies.
  30 * in exit.c or in signal.c.
  31 */
  32
  33/* determines which bits in the SR the user has access to. */
  34/* 1 = access 0 = no access */
  35#define SR_MASK 0x001f
  36
  37/* sets the trace bits. */
  38#define TRACE_BITS 0xC000
  39#define T1_BIT 0x8000
  40#define T0_BIT 0x4000
  41
  42/* Find the stack offset for a register, relative to thread.esp0. */
  43#define PT_REG(reg)     ((long)&((struct pt_regs *)0)->reg)
  44#define SW_REG(reg)     ((long)&((struct switch_stack *)0)->reg \
  45                         - sizeof(struct switch_stack))
  46/* Mapping from PT_xxx to the stack offset at which the register is
  47   saved.  Notice that usp has no stack-slot and needs to be treated
  48   specially (see get_reg/put_reg below). */
  49static const int regoff[] = {
  50        [0]     = PT_REG(d1),
  51        [1]     = PT_REG(d2),
  52        [2]     = PT_REG(d3),
  53        [3]     = PT_REG(d4),
  54        [4]     = PT_REG(d5),
  55        [5]     = SW_REG(d6),
  56        [6]     = SW_REG(d7),
  57        [7]     = PT_REG(a0),
  58        [8]     = PT_REG(a1),
  59        [9]     = PT_REG(a2),
  60        [10]    = SW_REG(a3),
  61        [11]    = SW_REG(a4),
  62        [12]    = SW_REG(a5),
  63        [13]    = SW_REG(a6),
  64        [14]    = PT_REG(d0),
  65        [15]    = -1,
  66        [16]    = PT_REG(orig_d0),
  67        [17]    = PT_REG(sr),
  68        [18]    = PT_REG(pc),
  69};
  70
  71/*
  72 * Get contents of register REGNO in task TASK.
  73 */
  74static inline long get_reg(struct task_struct *task, int regno)
  75{
  76        unsigned long *addr;
  77
  78        if (regno == PT_USP)
  79                addr = &task->thread.usp;
  80        else if (regno < ARRAY_SIZE(regoff))
  81                addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
  82        else
  83                return 0;
  84        /* Need to take stkadj into account. */
  85        if (regno == PT_SR || regno == PT_PC) {
  86                long stkadj = *(long *)(task->thread.esp0 + PT_REG(stkadj));
  87                addr = (unsigned long *) ((unsigned long)addr + stkadj);
  88                /* The sr is actually a 16 bit register.  */
  89                if (regno == PT_SR)
  90                        return *(unsigned short *)addr;
  91        }
  92        return *addr;
  93}
  94
  95/*
  96 * Write contents of register REGNO in task TASK.
  97 */
  98static inline int put_reg(struct task_struct *task, int regno,
  99                          unsigned long data)
 100{
 101        unsigned long *addr;
 102
 103        if (regno == PT_USP)
 104                addr = &task->thread.usp;
 105        else if (regno < ARRAY_SIZE(regoff))
 106                addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
 107        else
 108                return -1;
 109        /* Need to take stkadj into account. */
 110        if (regno == PT_SR || regno == PT_PC) {
 111                long stkadj = *(long *)(task->thread.esp0 + PT_REG(stkadj));
 112                addr = (unsigned long *) ((unsigned long)addr + stkadj);
 113                /* The sr is actually a 16 bit register.  */
 114                if (regno == PT_SR) {
 115                        *(unsigned short *)addr = data;
 116                        return 0;
 117                }
 118        }
 119        *addr = data;
 120        return 0;
 121}
 122
 123/*
 124 * Make sure the single step bit is not set.
 125 */
 126static inline void singlestep_disable(struct task_struct *child)
 127{
 128        unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS;
 129        put_reg(child, PT_SR, tmp);
 130        clear_tsk_thread_flag(child, TIF_DELAYED_TRACE);
 131}
 132
 133/*
 134 * Called by kernel/ptrace.c when detaching..
 135 */
 136void ptrace_disable(struct task_struct *child)
 137{
 138        singlestep_disable(child);
 139}
 140
 141void user_enable_single_step(struct task_struct *child)
 142{
 143        unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS;
 144        put_reg(child, PT_SR, tmp | T1_BIT);
 145        set_tsk_thread_flag(child, TIF_DELAYED_TRACE);
 146}
 147
 148#ifdef CONFIG_MMU
 149void user_enable_block_step(struct task_struct *child)
 150{
 151        unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS;
 152        put_reg(child, PT_SR, tmp | T0_BIT);
 153}
 154#endif
 155
 156void user_disable_single_step(struct task_struct *child)
 157{
 158        singlestep_disable(child);
 159}
 160
 161long arch_ptrace(struct task_struct *child, long request,
 162                 unsigned long addr, unsigned long data)
 163{
 164        unsigned long tmp;
 165        int i, ret = 0;
 166        int regno = addr >> 2; /* temporary hack. */
 167        unsigned long __user *datap = (unsigned long __user *) data;
 168
 169        switch (request) {
 170        /* read the word at location addr in the USER area. */
 171        case PTRACE_PEEKUSR:
 172                if (addr & 3)
 173                        goto out_eio;
 174
 175                if (regno >= 0 && regno < 19) {
 176                        tmp = get_reg(child, regno);
 177                } else if (regno >= 21 && regno < 49) {
 178                        tmp = child->thread.fp[regno - 21];
 179                        /* Convert internal fpu reg representation
 180                         * into long double format
 181                         */
 182                        if (FPU_IS_EMU && (regno < 45) && !(regno % 3))
 183                                tmp = ((tmp & 0xffff0000) << 15) |
 184                                      ((tmp & 0x0000ffff) << 16);
 185#ifndef CONFIG_MMU
 186                } else if (regno == 49) {
 187                        tmp = child->mm->start_code;
 188                } else if (regno == 50) {
 189                        tmp = child->mm->start_data;
 190                } else if (regno == 51) {
 191                        tmp = child->mm->end_code;
 192#endif
 193                } else
 194                        goto out_eio;
 195                ret = put_user(tmp, datap);
 196                break;
 197
 198        case PTRACE_POKEUSR:
 199        /* write the word at location addr in the USER area */
 200                if (addr & 3)
 201                        goto out_eio;
 202
 203                if (regno == PT_SR) {
 204                        data &= SR_MASK;
 205                        data |= get_reg(child, PT_SR) & ~SR_MASK;
 206                }
 207                if (regno >= 0 && regno < 19) {
 208                        if (put_reg(child, regno, data))
 209                                goto out_eio;
 210                } else if (regno >= 21 && regno < 48) {
 211                        /* Convert long double format
 212                         * into internal fpu reg representation
 213                         */
 214                        if (FPU_IS_EMU && (regno < 45) && !(regno % 3)) {
 215                                data <<= 15;
 216                                data = (data & 0xffff0000) |
 217                                       ((data & 0x0000ffff) >> 1);
 218                        }
 219                        child->thread.fp[regno - 21] = data;
 220                } else
 221                        goto out_eio;
 222                break;
 223
 224        case PTRACE_GETREGS:    /* Get all gp regs from the child. */
 225                for (i = 0; i < 19; i++) {
 226                        tmp = get_reg(child, i);
 227                        ret = put_user(tmp, datap);
 228                        if (ret)
 229                                break;
 230                        datap++;
 231                }
 232                break;
 233
 234        case PTRACE_SETREGS:    /* Set all gp regs in the child. */
 235                for (i = 0; i < 19; i++) {
 236                        ret = get_user(tmp, datap);
 237                        if (ret)
 238                                break;
 239                        if (i == PT_SR) {
 240                                tmp &= SR_MASK;
 241                                tmp |= get_reg(child, PT_SR) & ~SR_MASK;
 242                        }
 243                        put_reg(child, i, tmp);
 244                        datap++;
 245                }
 246                break;
 247
 248        case PTRACE_GETFPREGS:  /* Get the child FPU state. */
 249                if (copy_to_user(datap, &child->thread.fp,
 250                                 sizeof(struct user_m68kfp_struct)))
 251                        ret = -EFAULT;
 252                break;
 253
 254        case PTRACE_SETFPREGS:  /* Set the child FPU state. */
 255                if (copy_from_user(&child->thread.fp, datap,
 256                                   sizeof(struct user_m68kfp_struct)))
 257                        ret = -EFAULT;
 258                break;
 259
 260        case PTRACE_GET_THREAD_AREA:
 261                ret = put_user(task_thread_info(child)->tp_value, datap);
 262                break;
 263
 264        default:
 265                ret = ptrace_request(child, request, addr, data);
 266                break;
 267        }
 268
 269        return ret;
 270out_eio:
 271        return -EIO;
 272}
 273
 274asmlinkage void syscall_trace(void)
 275{
 276        ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 277                                 ? 0x80 : 0));
 278        /*
 279         * this isn't the same as continuing with a signal, but it will do
 280         * for normal use.  strace only continues with a signal if the
 281         * stopping signal is not SIGTRAP.  -brl
 282         */
 283        if (current->exit_code) {
 284                send_sig(current->exit_code, current, 1);
 285                current->exit_code = 0;
 286        }
 287}
 288
 289#if defined(CONFIG_COLDFIRE) || !defined(CONFIG_MMU)
 290asmlinkage int syscall_trace_enter(void)
 291{
 292        int ret = 0;
 293
 294        if (test_thread_flag(TIF_SYSCALL_TRACE))
 295                ret = tracehook_report_syscall_entry(task_pt_regs(current));
 296        return ret;
 297}
 298
 299asmlinkage void syscall_trace_leave(void)
 300{
 301        if (test_thread_flag(TIF_SYSCALL_TRACE))
 302                tracehook_report_syscall_exit(task_pt_regs(current), 0);
 303}
 304#endif /* CONFIG_COLDFIRE */
 305