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/pgtable.h>
  27#include <asm/processor.h>
  28
  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 SR the user has access to. */
  35/* 1 = access 0 = no access */
  36#define SR_MASK 0x001f
  37
  38/* sets the trace bits. */
  39#define TRACE_BITS 0xC000
  40#define T1_BIT 0x8000
  41#define T0_BIT 0x4000
  42
  43/* Find the stack offset for a register, relative to thread.esp0. */
  44#define PT_REG(reg)     ((long)&((struct pt_regs *)0)->reg)
  45#define SW_REG(reg)     ((long)&((struct switch_stack *)0)->reg \
  46                         - sizeof(struct switch_stack))
  47/* Mapping from PT_xxx to the stack offset at which the register is
  48   saved.  Notice that usp has no stack-slot and needs to be treated
  49   specially (see get_reg/put_reg below). */
  50static const int regoff[] = {
  51        [0]     = PT_REG(d1),
  52        [1]     = PT_REG(d2),
  53        [2]     = PT_REG(d3),
  54        [3]     = PT_REG(d4),
  55        [4]     = PT_REG(d5),
  56        [5]     = SW_REG(d6),
  57        [6]     = SW_REG(d7),
  58        [7]     = PT_REG(a0),
  59        [8]     = PT_REG(a1),
  60        [9]     = PT_REG(a2),
  61        [10]    = SW_REG(a3),
  62        [11]    = SW_REG(a4),
  63        [12]    = SW_REG(a5),
  64        [13]    = SW_REG(a6),
  65        [14]    = PT_REG(d0),
  66        [15]    = -1,
  67        [16]    = PT_REG(orig_d0),
  68        [17]    = PT_REG(sr),
  69        [18]    = PT_REG(pc),
  70};
  71
  72/*
  73 * Get contents of register REGNO in task TASK.
  74 */
  75static inline long get_reg(struct task_struct *task, int regno)
  76{
  77        unsigned long *addr;
  78
  79        if (regno == PT_USP)
  80                addr = &task->thread.usp;
  81        else if (regno < ARRAY_SIZE(regoff))
  82                addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
  83        else
  84                return 0;
  85        /* Need to take stkadj into account. */
  86        if (regno == PT_SR || regno == PT_PC) {
  87                long stkadj = *(long *)(task->thread.esp0 + PT_REG(stkadj));
  88                addr = (unsigned long *) ((unsigned long)addr + stkadj);
  89                /* The sr is actually a 16 bit register.  */
  90                if (regno == PT_SR)
  91                        return *(unsigned short *)addr;
  92        }
  93        return *addr;
  94}
  95
  96/*
  97 * Write contents of register REGNO in task TASK.
  98 */
  99static inline int put_reg(struct task_struct *task, int regno,
 100                          unsigned long data)
 101{
 102        unsigned long *addr;
 103
 104        if (regno == PT_USP)
 105                addr = &task->thread.usp;
 106        else if (regno < ARRAY_SIZE(regoff))
 107                addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
 108        else
 109                return -1;
 110        /* Need to take stkadj into account. */
 111        if (regno == PT_SR || regno == PT_PC) {
 112                long stkadj = *(long *)(task->thread.esp0 + PT_REG(stkadj));
 113                addr = (unsigned long *) ((unsigned long)addr + stkadj);
 114                /* The sr is actually a 16 bit register.  */
 115                if (regno == PT_SR) {
 116                        *(unsigned short *)addr = data;
 117                        return 0;
 118                }
 119        }
 120        *addr = data;
 121        return 0;
 122}
 123
 124/*
 125 * Make sure the single step bit is not set.
 126 */
 127static inline void singlestep_disable(struct task_struct *child)
 128{
 129        unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS;
 130        put_reg(child, PT_SR, tmp);
 131        clear_tsk_thread_flag(child, TIF_DELAYED_TRACE);
 132}
 133
 134/*
 135 * Called by kernel/ptrace.c when detaching..
 136 */
 137void ptrace_disable(struct task_struct *child)
 138{
 139        singlestep_disable(child);
 140}
 141
 142void user_enable_single_step(struct task_struct *child)
 143{
 144        unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS;
 145        put_reg(child, PT_SR, tmp | T1_BIT);
 146        set_tsk_thread_flag(child, TIF_DELAYED_TRACE);
 147}
 148
 149#ifdef CONFIG_MMU
 150void user_enable_block_step(struct task_struct *child)
 151{
 152        unsigned long tmp = get_reg(child, PT_SR) & ~TRACE_BITS;
 153        put_reg(child, PT_SR, tmp | T0_BIT);
 154}
 155#endif
 156
 157void user_disable_single_step(struct task_struct *child)
 158{
 159        singlestep_disable(child);
 160}
 161
 162long arch_ptrace(struct task_struct *child, long request,
 163                 unsigned long addr, unsigned long data)
 164{
 165        unsigned long tmp;
 166        int i, ret = 0;
 167        int regno = addr >> 2; /* temporary hack. */
 168        unsigned long __user *datap = (unsigned long __user *) data;
 169
 170        switch (request) {
 171        /* read the word at location addr in the USER area. */
 172        case PTRACE_PEEKUSR:
 173                if (addr & 3)
 174                        goto out_eio;
 175
 176                if (regno >= 0 && regno < 19) {
 177                        tmp = get_reg(child, regno);
 178                } else if (regno >= 21 && regno < 49) {
 179                        tmp = child->thread.fp[regno - 21];
 180                        /* Convert internal fpu reg representation
 181                         * into long double format
 182                         */
 183                        if (FPU_IS_EMU && (regno < 45) && !(regno % 3))
 184                                tmp = ((tmp & 0xffff0000) << 15) |
 185                                      ((tmp & 0x0000ffff) << 16);
 186#ifndef CONFIG_MMU
 187                } else if (regno == 49) {
 188                        tmp = child->mm->start_code;
 189                } else if (regno == 50) {
 190                        tmp = child->mm->start_data;
 191                } else if (regno == 51) {
 192                        tmp = child->mm->end_code;
 193#endif
 194                } else
 195                        goto out_eio;
 196                ret = put_user(tmp, datap);
 197                break;
 198
 199        case PTRACE_POKEUSR:
 200        /* write the word at location addr in the USER area */
 201                if (addr & 3)
 202                        goto out_eio;
 203
 204                if (regno == PT_SR) {
 205                        data &= SR_MASK;
 206                        data |= get_reg(child, PT_SR) & ~SR_MASK;
 207                }
 208                if (regno >= 0 && regno < 19) {
 209                        if (put_reg(child, regno, data))
 210                                goto out_eio;
 211                } else if (regno >= 21 && regno < 48) {
 212                        /* Convert long double format
 213                         * into internal fpu reg representation
 214                         */
 215                        if (FPU_IS_EMU && (regno < 45) && !(regno % 3)) {
 216                                data <<= 15;
 217                                data = (data & 0xffff0000) |
 218                                       ((data & 0x0000ffff) >> 1);
 219                        }
 220                        child->thread.fp[regno - 21] = data;
 221                } else
 222                        goto out_eio;
 223                break;
 224
 225        case PTRACE_GETREGS:    /* Get all gp regs from the child. */
 226                for (i = 0; i < 19; i++) {
 227                        tmp = get_reg(child, i);
 228                        ret = put_user(tmp, datap);
 229                        if (ret)
 230                                break;
 231                        datap++;
 232                }
 233                break;
 234
 235        case PTRACE_SETREGS:    /* Set all gp regs in the child. */
 236                for (i = 0; i < 19; i++) {
 237                        ret = get_user(tmp, datap);
 238                        if (ret)
 239                                break;
 240                        if (i == PT_SR) {
 241                                tmp &= SR_MASK;
 242                                tmp |= get_reg(child, PT_SR) & ~SR_MASK;
 243                        }
 244                        put_reg(child, i, tmp);
 245                        datap++;
 246                }
 247                break;
 248
 249        case PTRACE_GETFPREGS:  /* Get the child FPU state. */
 250                if (copy_to_user(datap, &child->thread.fp,
 251                                 sizeof(struct user_m68kfp_struct)))
 252                        ret = -EFAULT;
 253                break;
 254
 255        case PTRACE_SETFPREGS:  /* Set the child FPU state. */
 256                if (copy_from_user(&child->thread.fp, datap,
 257                                   sizeof(struct user_m68kfp_struct)))
 258                        ret = -EFAULT;
 259                break;
 260
 261        case PTRACE_GET_THREAD_AREA:
 262                ret = put_user(task_thread_info(child)->tp_value, datap);
 263                break;
 264
 265        default:
 266                ret = ptrace_request(child, request, addr, data);
 267                break;
 268        }
 269
 270        return ret;
 271out_eio:
 272        return -EIO;
 273}
 274
 275asmlinkage void syscall_trace(void)
 276{
 277        ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 278                                 ? 0x80 : 0));
 279        /*
 280         * this isn't the same as continuing with a signal, but it will do
 281         * for normal use.  strace only continues with a signal if the
 282         * stopping signal is not SIGTRAP.  -brl
 283         */
 284        if (current->exit_code) {
 285                send_sig(current->exit_code, current, 1);
 286                current->exit_code = 0;
 287        }
 288}
 289
 290#if defined(CONFIG_COLDFIRE) || !defined(CONFIG_MMU)
 291asmlinkage int syscall_trace_enter(void)
 292{
 293        int ret = 0;
 294
 295        if (test_thread_flag(TIF_SYSCALL_TRACE))
 296                ret = tracehook_report_syscall_entry(task_pt_regs(current));
 297        return ret;
 298}
 299
 300asmlinkage void syscall_trace_leave(void)
 301{
 302        if (test_thread_flag(TIF_SYSCALL_TRACE))
 303                tracehook_report_syscall_exit(task_pt_regs(current), 0);
 304}
 305#endif /* CONFIG_COLDFIRE */
 306