arch/mips/kernel/ptrace.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 1992 Ross Biro
   7  * Copyright (C) Linus Torvalds
   8  * Copyright (C) 1994, 95, 96, 97, 98, 2000 Ralf Baechle
   9  * Copyright (C) 1996 David S. Miller
  10  * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
  11  * Copyright (C) 1999 MIPS Technologies, Inc.
  12  */
  13 #include <linux/config.h>
  14 #include <linux/kernel.h>
  15 #include <linux/sched.h>
  16 #include <linux/mm.h>
  17 #include <linux/errno.h>
  18 #include <linux/ptrace.h>
  19 #include <linux/smp.h>
  20 #include <linux/smp_lock.h>
  21 #include <linux/user.h>
  22
  23 #include <asm/mipsregs.h>
  24 #include <asm/pgtable.h>
  25 #include <asm/page.h>
  26 #include <asm/system.h>
  27 #include <asm/uaccess.h>
  28 #include <asm/bootinfo.h>
  29 #include <asm/cpu.h>
  30 #include <asm/fpu.h>
  31
  32 /*
  33  * Called by kernel/ptrace.c when detaching..
  34  *
  35  * Make sure single step bits etc are not set.
  36  */
  37 void ptrace_disable(struct task_struct *child)
  38 {
  39         /* Nothing to do.. */
  40 }
  41
  42 asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
  43 {
  44         struct task_struct *child;
  45         int ret;
  46
  47         lock_kernel();
  48 #if 0
  49         printk("ptrace(r=%d,pid=%d,addr=%08lx,data=%08lx)\n",
  50                (int) request, (int) pid, (unsigned long) addr,
  51                (unsigned long) data);
  52 #endif
  53         if (request == PTRACE_TRACEME) {
  54                 /* are we already being traced? */
  55                 if (current->ptrace & PT_PTRACED) {
  56                         ret = -EPERM;
  57                         goto out;
  58                 }
  59                 /* set the ptrace bit in the process flags. */
  60                 current->ptrace |= PT_PTRACED;
  61                 ret = 0;
  62                 goto out;
  63         }
  64         ret = -ESRCH;
  65         read_lock(&tasklist_lock);
  66         child = find_task_by_pid(pid);
  67         if (child)
  68                 get_task_struct(child);
  69         read_unlock(&tasklist_lock);
  70         if (!child)
  71                 goto out;
  72
  73         ret = -EPERM;
  74         if (pid == 1)           /* you may not mess with init */
  75                 goto out_tsk;
  76
  77         if (request == PTRACE_ATTACH) {
  78                 ret = ptrace_attach(child);
  79                 goto out_tsk;
  80         }
  81
  82         ret = ptrace_check_attach(child, request == PTRACE_KILL);
  83         if (ret < 0)
  84                 goto out_tsk;
  85
  86         switch (request) {
  87         case PTRACE_PEEKTEXT: /* read word at location addr. */
  88         case PTRACE_PEEKDATA: {
  89                 unsigned long tmp;
  90                 int copied;
  91
  92                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
  93                 ret = -EIO;
  94                 if (copied != sizeof(tmp))
  95                         break;
  96                 ret = put_user(tmp,(unsigned long *) data);
  97                 break;
  98                 }
  99
 100         /* Read the word at location addr in the USER area.  */
 101         case PTRACE_PEEKUSR: {
 102                 struct pt_regs *regs;
 103                 unsigned long tmp;
 104
 105                 regs = (struct pt_regs *) ((unsigned long) child +
 106                        KERNEL_STACK_SIZE - 32 - sizeof(struct pt_regs));
 107                 tmp = 0;  /* Default return value. */
 108
 109                 switch(addr) {
 110                 case 0 ... 31:
 111                         tmp = regs->regs[addr];
 112                         break;
 113                 case FPR_BASE ... FPR_BASE + 31:
 114                         if (child->used_math) {
 115                                 unsigned long long *fregs = get_fpu_regs(child);
 116                                 /*
 117                                  * The odd registers are actually the high
 118                                  * order bits of the values stored in the even
 119                                  * registers - unless we're using r2k_switch.S.
 120                                  */
 121                                 if (addr & 1)
 122                                         tmp = (unsigned long) (fregs[((addr & ~1) - 32)] >> 32);
 123                                 else
 124                                         tmp = (unsigned long) (fregs[(addr - 32)] & 0xffffffff);
 125                         } else {
 126                                 tmp = -1;       /* FP not yet used  */
 127                         }
 128                         break;
 129                 case PC:
 130                         tmp = regs->cp0_epc;
 131                         break;
 132                 case CAUSE:
 133                         tmp = regs->cp0_cause;
 134                         break;
 135                 case BADVADDR:
 136                         tmp = regs->cp0_badvaddr;
 137                         break;
 138                 case MMHI:
 139                         tmp = regs->hi;
 140                         break;
 141                 case MMLO:
 142                         tmp = regs->lo;
 143                         break;
 144                 case FPC_CSR:
 145                         if (!cpu_has_fpu)
 146                                 tmp = child->thread.fpu.soft.sr;
 147                         else
 148                                 tmp = child->thread.fpu.hard.control;
 149                         break;
 150                 case FPC_EIR: { /* implementation / version register */
 151                         unsigned long flags;
 152
 153                         if (!cpu_has_fpu)
 154                                 break;
 155
 156                         __save_flags(flags);
 157                         __enable_fpu();
 158                         __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
 159                         __restore_flags(flags);
 160                         break;
 161                 }
 162                 default:
 163                         tmp = 0;
 164                         ret = -EIO;
 165                         goto out_tsk;
 166                 }
 167                 ret = put_user(tmp, (unsigned long *) data);
 168                 break;
 169                 }
 170
 171         case PTRACE_POKETEXT: /* write the word at location addr. */
 172         case PTRACE_POKEDATA:
 173                 ret = 0;
 174                 if (access_process_vm(child, addr, &data, sizeof(data), 1)
 175                     == sizeof(data))
 176                         break;
 177                 ret = -EIO;
 178                 break;
 179
 180         case PTRACE_POKEUSR: {
 181                 struct pt_regs *regs;
 182                 ret = 0;
 183                 regs = (struct pt_regs *) ((unsigned long) child +
 184                        KERNEL_STACK_SIZE - 32 - sizeof(struct pt_regs));
 185
 186                 switch (addr) {
 187                 case 0 ... 31:
 188                         regs->regs[addr] = data;
 189                         break;
 190                 case FPR_BASE ... FPR_BASE + 31: {
 191                         unsigned long long *fregs;
 192                         fregs = (unsigned long long *)get_fpu_regs(child);
 193                         if (!child->used_math) {
 194                                 /* FP not yet used  */
 195                                 memset(&child->thread.fpu.hard, ~0,
 196                                        sizeof(child->thread.fpu.hard));
 197                                 child->thread.fpu.hard.control = 0;
 198                         }
 199                         /*
 200                          * The odd registers are actually the high order bits
 201                          * of the values stored in the even registers - unless
 202                          * we're using r2k_switch.S.
 203                          */
 204                         if (addr & 1) {
 205                                 fregs[(addr & ~1) - FPR_BASE] &= 0xffffffff;
 206                                 fregs[(addr & ~1) - FPR_BASE] |= ((unsigned long long) data) << 32;
 207                         } else {
 208                                 fregs[addr - FPR_BASE] &= ~0xffffffffLL;
 209                                 fregs[addr - FPR_BASE] |= data;
 210                         }
 211                         break;
 212                 }
 213                 case PC:
 214                         regs->cp0_epc = data;
 215                         break;
 216                 case MMHI:
 217                         regs->hi = data;
 218                         break;
 219                 case MMLO:
 220                         regs->lo = data;
 221                         break;
 222                 case FPC_CSR:
 223                         if (!cpu_has_fpu)
 224                                 child->thread.fpu.soft.sr = data;
 225                         else
 226                                 child->thread.fpu.hard.control = data;
 227                         break;
 228                 default:
 229                         /* The rest are not allowed. */
 230                         ret = -EIO;
 231                         break;
 232                 }
 233                 break;
 234                 }
 235
 236         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 237         case PTRACE_CONT: { /* restart after signal. */
 238                 ret = -EIO;
 239                 if ((unsigned long) data > _NSIG)
 240                         break;
 241                 if (request == PTRACE_SYSCALL)
 242                         child->ptrace |= PT_TRACESYS;
 243                 else
 244                         child->ptrace &= ~PT_TRACESYS;
 245                 child->exit_code = data;
 246                 wake_up_process(child);
 247                 ret = 0;
 248                 break;
 249                 }
 250
 251         /*
 252          * make the child exit.  Best I can do is send it a sigkill.
 253          * perhaps it should be put in the status that it wants to
 254          * exit.
 255          */
 256         case PTRACE_KILL:
 257                 ret = 0;
 258                 if (child->state == TASK_ZOMBIE)        /* already dead */
 259                         break;
 260                 child->exit_code = SIGKILL;
 261                 wake_up_process(child);
 262                 break;
 263
 264         case PTRACE_DETACH: /* detach a process that was attached. */
 265                 ret = ptrace_detach(child, data);
 266                 break;
 267
 268         case PTRACE_SETOPTIONS:
 269                 if (data & PTRACE_O_TRACESYSGOOD)
 270                         child->ptrace |= PT_TRACESYSGOOD;
 271                 else
 272                         child->ptrace &= ~PT_TRACESYSGOOD;
 273                 ret = 0;
 274                 break;
 275
 276         default:
 277                 ret = -EIO;
 278                 break;
 279         }
 280 out_tsk:
 281         free_task_struct(child);
 282 out:
 283         unlock_kernel();
 284         return ret;
 285 }
 286
 287 asmlinkage void syscall_trace(void)
 288 {
 289         if ((current->ptrace & (PT_PTRACED|PT_TRACESYS))
 290                         != (PT_PTRACED|PT_TRACESYS))
 291                 return;
 292         /* The 0x80 provides a way for the tracing parent to distinguish
 293            between a syscall stop and SIGTRAP delivery */
 294         current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 295                                         ? 0x80 : 0);
 296         current->state = TASK_STOPPED;
 297         notify_parent(current, SIGCHLD);
 298         schedule();
 299         /*
 300          * this isn't the same as continuing with a signal, but it will do
 301          * for normal use.  strace only continues with a signal if the
 302          * stopping signal is not SIGTRAP.  -brl
 303          */
 304         if (current->exit_code) {
 305                 send_sig(current->exit_code, current, 1);
 306                 current->exit_code = 0;
 307         }
 308 }