arch/mips/kernel/ptrace32.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  * Copyright (C) 2000 Ulf Carlsson
  13  *
  14  * At this time Linux/MIPS64 only supports syscall tracing, even for 32-bit
  15  * binaries.
  16  */
  17 #include <linux/compiler.h>
  18 #include <linux/kernel.h>
  19 #include <linux/sched.h>
  20 #include <linux/mm.h>
  21 #include <linux/errno.h>
  22 #include <linux/ptrace.h>
  23 #include <linux/smp.h>
  24 #include <linux/smp_lock.h>
  25 #include <linux/user.h>
  26 #include <linux/security.h>
  27 #include <linux/signal.h>
  28
  29 #include <asm/cpu.h>
  30 #include <asm/fpu.h>
  31 #include <asm/mipsregs.h>
  32 #include <asm/pgtable.h>
  33 #include <asm/page.h>
  34 #include <asm/system.h>
  35 #include <asm/uaccess.h>
  36 #include <asm/bootinfo.h>
  37
  38 /*
  39  * Tracing a 32-bit process with a 64-bit strace and vice versa will not
  40  * work.  I don't know how to fix this.
  41  */
  42 asmlinkage int sys32_ptrace(int request, int pid, int addr, int data)
  43 {
  44         struct task_struct *child;
  45         int ret;
  46
  47 #if 0
  48         printk("ptrace(r=%d,pid=%d,addr=%08lx,data=%08lx)\n",
  49                (int) request, (int) pid, (unsigned long) addr,
  50                (unsigned long) data);
  51 #endif
  52         lock_kernel();
  53         ret = -EPERM;
  54         if (request == PTRACE_TRACEME) {
  55                 /* are we already being traced? */
  56                 if (current->ptrace & PT_PTRACED)
  57                         goto out;
  58                 if ((ret = security_ptrace(current->parent, current)))
  59                         goto out;
  60                 /* set the ptrace bit in the process flags. */
  61                 current->ptrace |= PT_PTRACED;
  62                 ret = 0;
  63                 goto out;
  64         }
  65         ret = -ESRCH;
  66         read_lock(&tasklist_lock);
  67         child = find_task_by_pid(pid);
  68         if (child)
  69                 get_task_struct(child);
  70         read_unlock(&tasklist_lock);
  71         if (!child)
  72                 goto out;
  73
  74         ret = -EPERM;
  75         if (pid == 1)           /* you may not mess with init */
  76                 goto out_tsk;
  77
  78         if (request == PTRACE_ATTACH) {
  79                 ret = ptrace_attach(child);
  80                 goto out_tsk;
  81         }
  82
  83         ret = ptrace_check_attach(child, request == PTRACE_KILL);
  84         if (ret < 0)
  85                 goto out_tsk;
  86
  87         switch (request) {
  88         /* when I and D space are separate, these will need to be fixed. */
  89         case PTRACE_PEEKTEXT: /* read word at location addr. */
  90         case PTRACE_PEEKDATA: {
  91                 unsigned int tmp;
  92                 int copied;
  93
  94                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
  95                 ret = -EIO;
  96                 if (copied != sizeof(tmp))
  97                         break;
  98                 ret = put_user(tmp, (unsigned int *) (unsigned long) data);
  99                 break;
 100         }
 101
 102         /* Read the word at location addr in the USER area. */
 103         case PTRACE_PEEKUSR: {
 104                 struct pt_regs *regs;
 105                 unsigned int tmp;
 106
 107                 regs = (struct pt_regs *) ((unsigned long) child->thread_info +
 108                        THREAD_SIZE - 32 - sizeof(struct pt_regs));
 109                 ret = 0;  /* Default return value. */
 110
 111                 switch (addr) {
 112                 case 0 ... 31:
 113                         tmp = regs->regs[addr];
 114                         break;
 115                 case FPR_BASE ... FPR_BASE + 31:
 116                         if (tsk_used_math(child)) {
 117                                 fpureg_t *fregs = get_fpu_regs(child);
 118
 119                                 /*
 120                                  * The odd registers are actually the high
 121                                  * order bits of the values stored in the even
 122                                  * registers - unless we're using r2k_switch.S.
 123                                  */
 124                                 if (addr & 1)
 125                                         tmp = (unsigned long) (fregs[((addr & ~1) - 32)] >> 32);
 126                                 else
 127                                         tmp = (unsigned long) (fregs[(addr - 32)] & 0xffffffff);
 128                         } else {
 129                                 tmp = -1;       /* FP not yet used  */
 130                         }
 131                         break;
 132                 case PC:
 133                         tmp = regs->cp0_epc;
 134                         break;
 135                 case CAUSE:
 136                         tmp = regs->cp0_cause;
 137                         break;
 138                 case BADVADDR:
 139                         tmp = regs->cp0_badvaddr;
 140                         break;
 141                 case MMHI:
 142                         tmp = regs->hi;
 143                         break;
 144                 case MMLO:
 145                         tmp = regs->lo;
 146                         break;
 147                 case FPC_CSR:
 148                         if (cpu_has_fpu)
 149                                 tmp = child->thread.fpu.hard.fcr31;
 150                         else
 151                                 tmp = child->thread.fpu.soft.fcr31;
 152                         break;
 153                 case FPC_EIR: { /* implementation / version register */
 154                         unsigned int flags;
 155
 156                         if (!cpu_has_fpu)
 157                                 break;
 158
 159                         flags = read_c0_status();
 160                         __enable_fpu();
 161                         __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
 162                         write_c0_status(flags);
 163                         break;
 164                 }
 165                 default:
 166                         tmp = 0;
 167                         ret = -EIO;
 168                         goto out_tsk;
 169                 }
 170                 ret = put_user(tmp, (unsigned *) (unsigned long) data);
 171                 break;
 172         }
 173
 174         /* when I and D space are separate, this will have to be fixed. */
 175         case PTRACE_POKETEXT: /* write the word at location addr. */
 176         case PTRACE_POKEDATA:
 177                 ret = 0;
 178                 if (access_process_vm(child, addr, &data, sizeof(data), 1)
 179                     == sizeof(data))
 180                         break;
 181                 ret = -EIO;
 182                 break;
 183
 184         case PTRACE_POKEUSR: {
 185                 struct pt_regs *regs;
 186                 ret = 0;
 187                 regs = (struct pt_regs *) ((unsigned long) child->thread_info +
 188                        THREAD_SIZE - 32 - sizeof(struct pt_regs));
 189
 190                 switch (addr) {
 191                 case 0 ... 31:
 192                         regs->regs[addr] = data;
 193                         break;
 194                 case FPR_BASE ... FPR_BASE + 31: {
 195                         fpureg_t *fregs = get_fpu_regs(child);
 196
 197                         if (!tsk_used_math(child)) {
 198                                 /* FP not yet used  */
 199                                 memset(&child->thread.fpu.hard, ~0,
 200                                        sizeof(child->thread.fpu.hard));
 201                                 child->thread.fpu.hard.fcr31 = 0;
 202                         }
 203                         /*
 204                          * The odd registers are actually the high order bits
 205                          * of the values stored in the even registers - unless
 206                          * we're using r2k_switch.S.
 207                          */
 208                         if (addr & 1) {
 209                                 fregs[(addr & ~1) - FPR_BASE] &= 0xffffffff;
 210                                 fregs[(addr & ~1) - FPR_BASE] |= ((unsigned long long) data) << 32;
 211                         } else {
 212                                 fregs[addr - FPR_BASE] &= ~0xffffffffLL;
 213                                 /* Must cast, lest sign extension fill upper
 214                                    bits!  */
 215                                 fregs[addr - FPR_BASE] |= (unsigned int)data;
 216                         }
 217                         break;
 218                 }
 219                 case PC:
 220                         regs->cp0_epc = data;
 221                         break;
 222                 case MMHI:
 223                         regs->hi = data;
 224                         break;
 225                 case MMLO:
 226                         regs->lo = data;
 227                         break;
 228                 case FPC_CSR:
 229                         if (cpu_has_fpu)
 230                                 child->thread.fpu.hard.fcr31 = data;
 231                         else
 232                                 child->thread.fpu.soft.fcr31 = data;
 233                         break;
 234                 default:
 235                         /* The rest are not allowed. */
 236                         ret = -EIO;
 237                         break;
 238                 }
 239                 break;
 240                 }
 241
 242         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 243         case PTRACE_CONT: { /* restart after signal. */
 244                 ret = -EIO;
 245                 if (!valid_signal(data))
 246                         break;
 247                 if (request == PTRACE_SYSCALL) {
 248                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 249                 }
 250                 else {
 251                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 252                 }
 253                 child->exit_code = data;
 254                 wake_up_process(child);
 255                 ret = 0;
 256                 break;
 257         }
 258
 259         /*
 260          * make the child exit.  Best I can do is send it a sigkill.
 261          * perhaps it should be put in the status that it wants to
 262          * exit.
 263          */
 264         case PTRACE_KILL:
 265                 ret = 0;
 266                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 267                         break;
 268                 child->exit_code = SIGKILL;
 269                 wake_up_process(child);
 270                 break;
 271
 272         case PTRACE_DETACH: /* detach a process that was attached. */
 273                 ret = ptrace_detach(child, data);
 274                 break;
 275
 276         default:
 277                 ret = ptrace_request(child, request, addr, data);
 278                 break;
 279         }
 280
 281 out_tsk:
 282         put_task_struct(child);
 283 out:
 284         unlock_kernel();
 285         return ret;
 286 }