arch/m68knommu/kernel/ptrace.c

   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 #include <linux/tracehook.h>
  22
  23 #include <asm/uaccess.h>
  24 #include <asm/page.h>
  25 #include <asm/pgtable.h>
  26 #include <asm/system.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 0x8000
  40
  41 /* Find the stack offset for a register, relative to thread.esp0. */
  42 #define PT_REG(reg)     ((long)&((struct pt_regs *)0)->reg)
  43 #define SW_REG(reg)     ((long)&((struct switch_stack *)0)->reg \
  44                          - sizeof(struct switch_stack))
  45 /* Mapping from PT_xxx to the stack offset at which the register is
  46    saved.  Notice that usp has no stack-slot and needs to be treated
  47    specially (see get_reg/put_reg below). */
  48 static int regoff[] = {
  49         PT_REG(d1), PT_REG(d2), PT_REG(d3), PT_REG(d4),
  50         PT_REG(d5), SW_REG(d6), SW_REG(d7), PT_REG(a0),
  51         PT_REG(a1), PT_REG(a2), SW_REG(a3), SW_REG(a4),
  52         SW_REG(a5), SW_REG(a6), PT_REG(d0), -1,
  53         PT_REG(orig_d0), PT_REG(sr), PT_REG(pc),
  54 };
  55
  56 /*
  57  * Get contents of register REGNO in task TASK.
  58  */
  59 static inline long get_reg(struct task_struct *task, int regno)
  60 {
  61         unsigned long *addr;
  62
  63         if (regno == PT_USP)
  64                 addr = &task->thread.usp;
  65         else if (regno < ARRAY_SIZE(regoff))
  66                 addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
  67         else
  68                 return 0;
  69         return *addr;
  70 }
  71
  72 /*
  73  * Write contents of register REGNO in task TASK.
  74  */
  75 static inline int put_reg(struct task_struct *task, int regno,
  76                           unsigned long data)
  77 {
  78         unsigned long *addr;
  79
  80         if (regno == PT_USP)
  81                 addr = &task->thread.usp;
  82         else if (regno < ARRAY_SIZE(regoff))
  83                 addr = (unsigned long *) (task->thread.esp0 + regoff[regno]);
  84         else
  85                 return -1;
  86         *addr = data;
  87         return 0;
  88 }
  89
  90 void user_enable_single_step(struct task_struct *task)
  91 {
  92         unsigned long srflags;
  93         srflags = get_reg(task, PT_SR) | (TRACE_BITS << 16);
  94         put_reg(task, PT_SR, srflags);
  95 }
  96
  97 void user_disable_single_step(struct task_struct *task)
  98 {
  99         unsigned long srflags;
 100         srflags = get_reg(task, PT_SR) & ~(TRACE_BITS << 16);
 101         put_reg(task, PT_SR, srflags);
 102 }
 103
 104 /*
 105  * Called by kernel/ptrace.c when detaching..
 106  *
 107  * Make sure the single step bit is not set.
 108  */
 109 void ptrace_disable(struct task_struct *child)
 110 {
 111         /* make sure the single step bit is not set. */
 112         user_disable_single_step(child);
 113 }
 114
 115 long arch_ptrace(struct task_struct *child, long request,
 116                  unsigned long addr, unsigned long data)
 117 {
 118         int ret;
 119
 120         switch (request) {
 121                 /* read the word at location addr in the USER area. */
 122                 case PTRACE_PEEKUSR: {
 123                         unsigned long tmp;
 124
 125                         ret = -EIO;
 126                         if ((addr & 3) || addr < 0 ||
 127                             addr > sizeof(struct user) - 3)
 128                                 break;
 129
 130                         tmp = 0;  /* Default return condition */
 131                         addr = addr >> 2; /* temporary hack. */
 132                         ret = -EIO;
 133                         if (addr < 19) {
 134                                 tmp = get_reg(child, addr);
 135                                 if (addr == PT_SR)
 136                                         tmp >>= 16;
 137                         } else if (addr >= 21 && addr < 49) {
 138                                 tmp = child->thread.fp[addr - 21];
 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                 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 152                         ret = -EIO;
 153                         if ((addr & 3) || addr < 0 ||
 154                             addr > sizeof(struct user) - 3)
 155                                 break;
 156
 157                         addr = addr >> 2; /* temporary hack. */
 158
 159                         if (addr == PT_SR) {
 160                                 data &= SR_MASK;
 161                                 data <<= 16;
 162                                 data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 163                         }
 164                         if (addr < 19) {
 165                                 if (put_reg(child, addr, data))
 166                                         break;
 167                                 ret = 0;
 168                                 break;
 169                         }
 170                         if (addr >= 21 && addr < 48)
 171                         {
 172                                 child->thread.fp[addr - 21] = data;
 173                                 ret = 0;
 174                         }
 175                         break;
 176
 177                 case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 178                         int i;
 179                         unsigned long tmp;
 180                         for (i = 0; i < 19; i++) {
 181                             tmp = get_reg(child, i);
 182                             if (i == PT_SR)
 183                                 tmp >>= 16;
 184                             if (put_user(tmp, (unsigned long *) data)) {
 185                                 ret = -EFAULT;
 186                                 break;
 187                             }
 188                             data += sizeof(unsigned long);
 189                         }
 190                         ret = 0;
 191                         break;
 192                 }
 193
 194                 case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 195                         int i;
 196                         unsigned long tmp;
 197                         for (i = 0; i < 19; i++) {
 198                             if (get_user(tmp, (unsigned long *) data)) {
 199                                 ret = -EFAULT;
 200                                 break;
 201                             }
 202                             if (i == PT_SR) {
 203                                 tmp &= SR_MASK;
 204                                 tmp <<= 16;
 205                                 tmp |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
 206                             }
 207                             put_reg(child, i, tmp);
 208                             data += sizeof(unsigned long);
 209                         }
 210                         ret = 0;
 211                         break;
 212                 }
 213
 214 #ifdef PTRACE_GETFPREGS
 215                 case PTRACE_GETFPREGS: { /* Get the child FPU state. */
 216                         ret = 0;
 217                         if (copy_to_user((void *)data, &child->thread.fp,
 218                                          sizeof(struct user_m68kfp_struct)))
 219                                 ret = -EFAULT;
 220                         break;
 221                 }
 222 #endif
 223
 224 #ifdef PTRACE_SETFPREGS
 225                 case PTRACE_SETFPREGS: { /* Set the child FPU state. */
 226                         ret = 0;
 227                         if (copy_from_user(&child->thread.fp, (void *)data,
 228                                            sizeof(struct user_m68kfp_struct)))
 229                                 ret = -EFAULT;
 230                         break;
 231                 }
 232 #endif
 233
 234         case PTRACE_GET_THREAD_AREA:
 235                 ret = put_user(task_thread_info(child)->tp_value,
 236                                (unsigned long __user *)data);
 237                 break;
 238
 239                 default:
 240                         ret = ptrace_request(child, request, addr, data);
 241                         break;
 242         }
 243         return ret;
 244 }
 245
 246 asmlinkage int syscall_trace_enter(void)
 247 {
 248         int ret = 0;
 249
 250         if (test_thread_flag(TIF_SYSCALL_TRACE))
 251                 ret = tracehook_report_syscall_entry(task_pt_regs(current));
 252         return ret;
 253 }
 254
 255 asmlinkage void syscall_trace_leave(void)
 256 {
 257         if (test_thread_flag(TIF_SYSCALL_TRACE))
 258                 tracehook_report_syscall_exit(task_pt_regs(current), 0);
 259 }