linux/arch/m68knommu/kernel/ptrace.c
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   1/*
   2 *  linux/arch/m68knommu/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/mm.h>
  16#include <linux/smp.h>
  17#include <linux/errno.h>
  18#include <linux/ptrace.h>
  19#include <linux/user.h>
  20#include <linux/signal.h>
  21
  22#include <asm/uaccess.h>
  23#include <asm/page.h>
  24#include <asm/pgtable.h>
  25#include <asm/system.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 0x8000
  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#define SW_REG(reg)     ((long)&((struct switch_stack *)0)->reg \
  43                         - sizeof(struct switch_stack))
  44/* Mapping from PT_xxx to the stack offset at which the register is
  45   saved.  Notice that usp has no stack-slot and needs to be treated
  46   specially (see get_reg/put_reg below). */
  47static int regoff[] = {
  48        PT_REG(d1), PT_REG(d2), PT_REG(d3), PT_REG(d4),
  49        PT_REG(d5), SW_REG(d6), SW_REG(d7), PT_REG(a0),
  50        PT_REG(a1), PT_REG(a2), SW_REG(a3), SW_REG(a4),
  51        SW_REG(a5), SW_REG(a6), PT_REG(d0), -1,
  52        PT_REG(orig_d0), PT_REG(sr), PT_REG(pc),
  53};
  54
  55/*
  56 * Get contents of register REGNO in task TASK.
  57 */
  58static inline long get_reg(struct task_struct *task, int regno)
  59{
  60        unsigned long *addr;
  61
  62        if (regno == PT_USP)
  63                addr = &task->thread.usp;
  64        else if (regno < ARRAY_SIZE(regoff))
  65                addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
  66        else
  67                return 0;
  68        return *addr;
  69}
  70
  71/*
  72 * Write contents of register REGNO in task TASK.
  73 */
  74static inline int put_reg(struct task_struct *task, int regno,
  75                          unsigned long data)
  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 -1;
  85        *addr = data;
  86        return 0;
  87}
  88
  89/*
  90 * Called by kernel/ptrace.c when detaching..
  91 *
  92 * Make sure the single step bit is not set.
  93 */
  94void ptrace_disable(struct task_struct *child)
  95{
  96        unsigned long tmp;
  97        /* make sure the single step bit is not set. */
  98        tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
  99        put_reg(child, PT_SR, tmp);
 100}
 101
 102long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 103{
 104        int ret;
 105
 106        switch (request) {
 107                /* when I and D space are separate, these will need to be fixed. */
 108                case PTRACE_PEEKTEXT: /* read word at location addr. */ 
 109                case PTRACE_PEEKDATA:
 110                        ret = generic_ptrace_peekdata(child, addr, data);
 111                        break;
 112
 113                /* read the word at location addr in the USER area. */
 114                case PTRACE_PEEKUSR: {
 115                        unsigned long tmp;
 116                        
 117                        ret = -EIO;
 118                        if ((addr & 3) || addr < 0 ||
 119                            addr > sizeof(struct user) - 3)
 120                                break;
 121                        
 122                        tmp = 0;  /* Default return condition */
 123                        addr = addr >> 2; /* temporary hack. */
 124                        ret = -EIO;
 125                        if (addr < 19) {
 126                                tmp = get_reg(child, addr);
 127                                if (addr == PT_SR)
 128                                        tmp >>= 16;
 129                        } else if (addr >= 21 && addr < 49) {
 130                                tmp = child->thread.fp[addr - 21];
 131#ifdef CONFIG_M68KFPU_EMU
 132                                /* Convert internal fpu reg representation
 133                                 * into long double format
 134                                 */
 135                                if (FPU_IS_EMU && (addr < 45) && !(addr % 3))
 136                                        tmp = ((tmp & 0xffff0000) << 15) |
 137                                              ((tmp & 0x0000ffff) << 16);
 138#endif
 139                        } else if (addr == 49) {
 140                                tmp = child->mm->start_code;
 141                        } else if (addr == 50) {
 142                                tmp = child->mm->start_data;
 143                        } else if (addr == 51) {
 144                                tmp = child->mm->end_code;
 145                        } else
 146                                break;
 147                        ret = put_user(tmp,(unsigned long *) data);
 148                        break;
 149                }
 150
 151                /* when I and D space are separate, this will have to be fixed. */
 152                case PTRACE_POKETEXT: /* write the word at location addr. */
 153                case PTRACE_POKEDATA:
 154                        ret = generic_ptrace_pokedata(child, addr, data);
 155                        break;
 156
 157                case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 158                        ret = -EIO;
 159                        if ((addr & 3) || addr < 0 ||
 160                            addr > sizeof(struct user) - 3)
 161                                break;
 162
 163                        addr = addr >> 2; /* temporary hack. */
 164                            
 165                        if (addr == PT_SR) {
 166                                data &= SR_MASK;
 167                                data <<= 16;
 168                                data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 169                        }
 170                        if (addr < 19) {
 171                                if (put_reg(child, addr, data))
 172                                        break;
 173                                ret = 0;
 174                                break;
 175                        }
 176                        if (addr >= 21 && addr < 48)
 177                        {
 178#ifdef CONFIG_M68KFPU_EMU
 179                                /* Convert long double format
 180                                 * into internal fpu reg representation
 181                                 */
 182                                if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) {
 183                                        data = (unsigned long)data << 15;
 184                                        data = (data & 0xffff0000) |
 185                                               ((data & 0x0000ffff) >> 1);
 186                                }
 187#endif
 188                                child->thread.fp[addr - 21] = data;
 189                                ret = 0;
 190                        }
 191                        break;
 192
 193                case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 194                case PTRACE_CONT: { /* restart after signal. */
 195                        long tmp;
 196
 197                        ret = -EIO;
 198                        if (!valid_signal(data))
 199                                break;
 200                        if (request == PTRACE_SYSCALL)
 201                                set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 202                        else
 203                                clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 204                        child->exit_code = data;
 205                        /* make sure the single step bit is not set. */
 206                        tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 207                        put_reg(child, PT_SR, tmp);
 208                        wake_up_process(child);
 209                        ret = 0;
 210                        break;
 211                }
 212
 213                /*
 214                 * make the child exit.  Best I can do is send it a sigkill. 
 215                 * perhaps it should be put in the status that it wants to 
 216                 * exit.
 217                 */
 218                case PTRACE_KILL: {
 219                        long tmp;
 220
 221                        ret = 0;
 222                        if (child->exit_state == EXIT_ZOMBIE) /* already dead */
 223                                break;
 224                        child->exit_code = SIGKILL;
 225                        /* make sure the single step bit is not set. */
 226                        tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
 227                        put_reg(child, PT_SR, tmp);
 228                        wake_up_process(child);
 229                        break;
 230                }
 231
 232                case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 233                        long tmp;
 234
 235                        ret = -EIO;
 236                        if (!valid_signal(data))
 237                                break;
 238                        clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 239                        tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16);
 240                        put_reg(child, PT_SR, tmp);
 241
 242                        child->exit_code = data;
 243                        /* give it a chance to run. */
 244                        wake_up_process(child);
 245                        ret = 0;
 246                        break;
 247                }
 248
 249                case PTRACE_DETACH:     /* detach a process that was attached. */
 250                        ret = ptrace_detach(child, data);
 251                        break;
 252
 253                case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 254                        int i;
 255                        unsigned long tmp;
 256                        for (i = 0; i < 19; i++) {
 257                            tmp = get_reg(child, i);
 258                            if (i == PT_SR)
 259                                tmp >>= 16;
 260                            if (put_user(tmp, (unsigned long *) data)) {
 261                                ret = -EFAULT;
 262                                break;
 263                            }
 264                            data += sizeof(long);
 265                        }
 266                        ret = 0;
 267                        break;
 268                }
 269
 270                case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 271                        int i;
 272                        unsigned long tmp;
 273                        for (i = 0; i < 19; i++) {
 274                            if (get_user(tmp, (unsigned long *) data)) {
 275                                ret = -EFAULT;
 276                                break;
 277                            }
 278                            if (i == PT_SR) {
 279                                tmp &= SR_MASK;
 280                                tmp <<= 16;
 281                                tmp |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 282                            }
 283                            put_reg(child, i, tmp);
 284                            data += sizeof(long);
 285                        }
 286                        ret = 0;
 287                        break;
 288                }
 289
 290#ifdef PTRACE_GETFPREGS
 291                case PTRACE_GETFPREGS: { /* Get the child FPU state. */
 292                        ret = 0;
 293                        if (copy_to_user((void *)data, &child->thread.fp,
 294                                         sizeof(struct user_m68kfp_struct)))
 295                                ret = -EFAULT;
 296                        break;
 297                }
 298#endif
 299
 300#ifdef PTRACE_SETFPREGS
 301                case PTRACE_SETFPREGS: { /* Set the child FPU state. */
 302                        ret = 0;
 303                        if (copy_from_user(&child->thread.fp, (void *)data,
 304                                           sizeof(struct user_m68kfp_struct)))
 305                                ret = -EFAULT;
 306                        break;
 307                }
 308#endif
 309
 310                default:
 311                        ret = -EIO;
 312                        break;
 313        }
 314        return ret;
 315}
 316
 317asmlinkage void syscall_trace(void)
 318{
 319        if (!test_thread_flag(TIF_SYSCALL_TRACE))
 320                return;
 321        if (!(current->ptrace & PT_PTRACED))
 322                return;
 323        ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 324                                 ? 0x80 : 0));
 325        /*
 326         * this isn't the same as continuing with a signal, but it will do
 327         * for normal use.  strace only continues with a signal if the
 328         * stopping signal is not SIGTRAP.  -brl
 329         */
 330        if (current->exit_code) {
 331                send_sig(current->exit_code, current, 1);
 332                current->exit_code = 0;
 333        }
 334}
 335
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