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   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/config.h>
  18 #include <linux/compiler.h>
  19 #include <linux/kernel.h>
  20 #include <linux/sched.h>
  21 #include <linux/mm.h>
  22 #include <linux/errno.h>
  23 #include <linux/ptrace.h>
  24 #include <linux/audit.h>
  25 #include <linux/smp.h>
  26 #include <linux/smp_lock.h>
  27 #include <linux/user.h>
  28 #include <linux/security.h>
  29 #include <linux/signal.h>
  30
  31 #include <asm/byteorder.h>
  32 #include <asm/cpu.h>
  33 #include <asm/fpu.h>
  34 #include <asm/mipsregs.h>
  35 #include <asm/pgtable.h>
  36 #include <asm/page.h>
  37 #include <asm/system.h>
  38 #include <asm/uaccess.h>
  39 #include <asm/bootinfo.h>
  40
  41 /*
  42  * Called by kernel/ptrace.c when detaching..
  43  *
  44  * Make sure single step bits etc are not set.
  45  */
  46 void ptrace_disable(struct task_struct *child)
  47 {
  48         /* Nothing to do.. */
  49 }
  50
  51 asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
  52 {
  53         struct task_struct *child;
  54         int ret;
  55
  56 #if 0
  57         printk("ptrace(r=%d,pid=%d,addr=%08lx,data=%08lx)\n",
  58                (int) request, (int) pid, (unsigned long) addr,
  59                (unsigned long) data);
  60 #endif
  61         lock_kernel();
  62         ret = -EPERM;
  63         if (request == PTRACE_TRACEME) {
  64                 /* are we already being traced? */
  65                 if (current->ptrace & PT_PTRACED)
  66                         goto out;
  67                 if ((ret = security_ptrace(current->parent, current)))
  68                         goto out;
  69                 /* set the ptrace bit in the process flags. */
  70                 current->ptrace |= PT_PTRACED;
  71                 ret = 0;
  72                 goto out;
  73         }
  74         ret = -ESRCH;
  75         read_lock(&tasklist_lock);
  76         child = find_task_by_pid(pid);
  77         if (child)
  78                 get_task_struct(child);
  79         read_unlock(&tasklist_lock);
  80         if (!child)
  81                 goto out;
  82
  83         ret = -EPERM;
  84         if (pid == 1)           /* you may not mess with init */
  85                 goto out_tsk;
  86
  87         if (request == PTRACE_ATTACH) {
  88                 ret = ptrace_attach(child);
  89                 goto out_tsk;
  90         }
  91
  92         ret = ptrace_check_attach(child, request == PTRACE_KILL);
  93         if (ret < 0)
  94                 goto out_tsk;
  95
  96         switch (request) {
  97         /* when I and D space are separate, these will need to be fixed. */
  98         case PTRACE_PEEKTEXT: /* read word at location addr. */
  99         case PTRACE_PEEKDATA: {
 100                 unsigned long tmp;
 101                 int copied;
 102
 103                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 104                 ret = -EIO;
 105                 if (copied != sizeof(tmp))
 106                         break;
 107                 ret = put_user(tmp,(unsigned long __user *) data);
 108                 break;
 109         }
 110
 111         /* Read the word at location addr in the USER area. */
 112         case PTRACE_PEEKUSR: {
 113                 struct pt_regs *regs;
 114                 unsigned long tmp = 0;
 115
 116                 regs = (struct pt_regs *) ((unsigned long) child->thread_info +
 117                        THREAD_SIZE - 32 - sizeof(struct pt_regs));
 118                 ret = 0;  /* Default return value. */
 119
 120                 switch (addr) {
 121                 case 0 ... 31:
 122                         tmp = regs->regs[addr];
 123                         break;
 124                 case FPR_BASE ... FPR_BASE + 31:
 125                         if (tsk_used_math(child)) {
 126                                 fpureg_t *fregs = get_fpu_regs(child);
 127
 128 #ifdef CONFIG_32BIT
 129                                 /*
 130                                  * The odd registers are actually the high
 131                                  * order bits of the values stored in the even
 132                                  * registers - unless we're using r2k_switch.S.
 133                                  */
 134                                 if (addr & 1)
 135                                         tmp = (unsigned long) (fregs[((addr & ~1) - 32)] >> 32);
 136                                 else
 137                                         tmp = (unsigned long) (fregs[(addr - 32)] & 0xffffffff);
 138 #endif
 139 #ifdef CONFIG_64BIT
 140                                 tmp = fregs[addr - FPR_BASE];
 141 #endif
 142                         } else {
 143                                 tmp = -1;       /* FP not yet used  */
 144                         }
 145                         break;
 146                 case PC:
 147                         tmp = regs->cp0_epc;
 148                         break;
 149                 case CAUSE:
 150                         tmp = regs->cp0_cause;
 151                         break;
 152                 case BADVADDR:
 153                         tmp = regs->cp0_badvaddr;
 154                         break;
 155                 case MMHI:
 156                         tmp = regs->hi;
 157                         break;
 158                 case MMLO:
 159                         tmp = regs->lo;
 160                         break;
 161                 case FPC_CSR:
 162                         if (cpu_has_fpu)
 163                                 tmp = child->thread.fpu.hard.fcr31;
 164                         else
 165                                 tmp = child->thread.fpu.soft.fcr31;
 166                         break;
 167                 case FPC_EIR: { /* implementation / version register */
 168                         unsigned int flags;
 169
 170                         if (!cpu_has_fpu)
 171                                 break;
 172
 173                         flags = read_c0_status();
 174                         __enable_fpu();
 175                         __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
 176                         write_c0_status(flags);
 177                         break;
 178                 }
 179                 default:
 180                         tmp = 0;
 181                         ret = -EIO;
 182                         goto out_tsk;
 183                 }
 184                 ret = put_user(tmp, (unsigned long __user *) data);
 185                 break;
 186         }
 187
 188         /* when I and D space are separate, this will have to be fixed. */
 189         case PTRACE_POKETEXT: /* write the word at location addr. */
 190         case PTRACE_POKEDATA:
 191                 ret = 0;
 192                 if (access_process_vm(child, addr, &data, sizeof(data), 1)
 193                     == sizeof(data))
 194                         break;
 195                 ret = -EIO;
 196                 break;
 197
 198         case PTRACE_POKEUSR: {
 199                 struct pt_regs *regs;
 200                 ret = 0;
 201                 regs = (struct pt_regs *) ((unsigned long) child->thread_info +
 202                        THREAD_SIZE - 32 - sizeof(struct pt_regs));
 203
 204                 switch (addr) {
 205                 case 0 ... 31:
 206                         regs->regs[addr] = data;
 207                         break;
 208                 case FPR_BASE ... FPR_BASE + 31: {
 209                         fpureg_t *fregs = get_fpu_regs(child);
 210
 211                         if (!tsk_used_math(child)) {
 212                                 /* FP not yet used  */
 213                                 memset(&child->thread.fpu.hard, ~0,
 214                                        sizeof(child->thread.fpu.hard));
 215                                 child->thread.fpu.hard.fcr31 = 0;
 216                         }
 217 #ifdef CONFIG_32BIT
 218                         /*
 219                          * The odd registers are actually the high order bits
 220                          * of the values stored in the even registers - unless
 221                          * we're using r2k_switch.S.
 222                          */
 223                         if (addr & 1) {
 224                                 fregs[(addr & ~1) - FPR_BASE] &= 0xffffffff;
 225                                 fregs[(addr & ~1) - FPR_BASE] |= ((unsigned long long) data) << 32;
 226                         } else {
 227                                 fregs[addr - FPR_BASE] &= ~0xffffffffLL;
 228                                 fregs[addr - FPR_BASE] |= data;
 229                         }
 230 #endif
 231 #ifdef CONFIG_64BIT
 232                         fregs[addr - FPR_BASE] = data;
 233 #endif
 234                         break;
 235                 }
 236                 case PC:
 237                         regs->cp0_epc = data;
 238                         break;
 239                 case MMHI:
 240                         regs->hi = data;
 241                         break;
 242                 case MMLO:
 243                         regs->lo = data;
 244                         break;
 245                 case FPC_CSR:
 246                         if (cpu_has_fpu)
 247                                 child->thread.fpu.hard.fcr31 = data;
 248                         else
 249                                 child->thread.fpu.soft.fcr31 = data;
 250                         break;
 251                 default:
 252                         /* The rest are not allowed. */
 253                         ret = -EIO;
 254                         break;
 255                 }
 256                 break;
 257                 }
 258
 259         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 260         case PTRACE_CONT: { /* restart after signal. */
 261                 ret = -EIO;
 262                 if (!valid_signal(data))
 263                         break;
 264                 if (request == PTRACE_SYSCALL) {
 265                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 266                 }
 267                 else {
 268                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 269                 }
 270                 child->exit_code = data;
 271                 wake_up_process(child);
 272                 ret = 0;
 273                 break;
 274         }
 275
 276         /*
 277          * make the child exit.  Best I can do is send it a sigkill.
 278          * perhaps it should be put in the status that it wants to
 279          * exit.
 280          */
 281         case PTRACE_KILL:
 282                 ret = 0;
 283                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 284                         break;
 285                 child->exit_code = SIGKILL;
 286                 wake_up_process(child);
 287                 break;
 288
 289         case PTRACE_DETACH: /* detach a process that was attached. */
 290                 ret = ptrace_detach(child, data);
 291                 break;
 292
 293         case PTRACE_GET_THREAD_AREA:
 294                 ret = put_user(child->thread_info->tp_value,
 295                                 (unsigned long __user *) data);
 296                 break;
 297
 298         default:
 299                 ret = ptrace_request(child, request, addr, data);
 300                 break;
 301         }
 302
 303 out_tsk:
 304         put_task_struct(child);
 305 out:
 306         unlock_kernel();
 307         return ret;
 308 }
 309
 310 static inline int audit_arch(void)
 311 {
 312         int arch = EM_MIPS;
 313 #ifdef CONFIG_64BIT
 314         arch |=  __AUDIT_ARCH_64BIT;
 315 #endif
 316 #if defined(__LITTLE_ENDIAN)
 317         arch |=  __AUDIT_ARCH_LE;
 318 #endif
 319         return arch;
 320 }
 321
 322 /*
 323  * Notification of system call entry/exit
 324  * - triggered by current->work.syscall_trace
 325  */
 326 asmlinkage void do_syscall_trace(struct pt_regs *regs, int entryexit)
 327 {
 328         if (unlikely(current->audit_context) && entryexit)
 329                 audit_syscall_exit(current, AUDITSC_RESULT(regs->regs[2]),
 330                                    regs->regs[2]);
 331
 332         if (!(current->ptrace & PT_PTRACED))
 333                 goto out;
 334         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 335                 goto out;
 336
 337         /* The 0x80 provides a way for the tracing parent to distinguish
 338            between a syscall stop and SIGTRAP delivery */
 339         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ?
 340                                  0x80 : 0));
 341
 342         /*
 343          * this isn't the same as continuing with a signal, but it will do
 344          * for normal use.  strace only continues with a signal if the
 345          * stopping signal is not SIGTRAP.  -brl
 346          */
 347         if (current->exit_code) {
 348                 send_sig(current->exit_code, current, 1);
 349                 current->exit_code = 0;
 350         }
 351  out:
 352         if (unlikely(current->audit_context) && !entryexit)
 353                 audit_syscall_entry(current, audit_arch(), regs->regs[2],
 354                                     regs->regs[4], regs->regs[5],
 355                                     regs->regs[6], regs->regs[7]);
 356 }