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