arch/ppc64/kernel/ptrace.c

   1 /*
   2  *  linux/arch/ppc64/kernel/ptrace.c
   3  *
   4  *  PowerPC version
   5  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
   6  *
   7  *  Derived from "arch/m68k/kernel/ptrace.c"
   8  *  Copyright (C) 1994 by Hamish Macdonald
   9  *  Taken from linux/kernel/ptrace.c and modified for M680x0.
  10  *  linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
  11  *
  12  * Modified by Cort Dougan (cort@hq.fsmlabs.com)
  13  * and Paul Mackerras (paulus@linuxcare.com.au).
  14  *
  15  * This file is subject to the terms and conditions of the GNU General
  16  * Public License.  See the file README.legal in the main directory of
  17  * this archive for more details.
  18  */
  19
  20 #include <linux/kernel.h>
  21 #include <linux/sched.h>
  22 #include <linux/mm.h>
  23 #include <linux/smp.h>
  24 #include <linux/smp_lock.h>
  25 #include <linux/errno.h>
  26 #include <linux/ptrace.h>
  27 #include <linux/user.h>
  28 #include <linux/security.h>
  29 #include <linux/audit.h>
  30 #include <linux/seccomp.h>
  31
  32 #include <asm/uaccess.h>
  33 #include <asm/page.h>
  34 #include <asm/pgtable.h>
  35 #include <asm/system.h>
  36 #include <asm/ptrace-common.h>
  37
  38 /*
  39  * does not yet catch signals sent when the child dies.
  40  * in exit.c or in signal.c.
  41  */
  42
  43 /*
  44  * Called by kernel/ptrace.c when detaching..
  45  *
  46  * Make sure single step bits etc are not set.
  47  */
  48 void ptrace_disable(struct task_struct *child)
  49 {
  50         /* make sure the single step bit is not set. */
  51         clear_single_step(child);
  52 }
  53
  54 int sys_ptrace(long request, long pid, long addr, long data)
  55 {
  56         struct task_struct *child;
  57         int ret = -EPERM;
  58
  59         lock_kernel();
  60         if (request == PTRACE_TRACEME) {
  61                 /* are we already being traced? */
  62                 if (current->ptrace & PT_PTRACED)
  63                         goto out;
  64                 ret = security_ptrace(current->parent, current);
  65                 if (ret)
  66                         goto out;
  67                 /* set the ptrace bit in the process flags. */
  68                 current->ptrace |= PT_PTRACED;
  69                 ret = 0;
  70                 goto out;
  71         }
  72         ret = -ESRCH;
  73         read_lock(&tasklist_lock);
  74         child = find_task_by_pid(pid);
  75         if (child)
  76                 get_task_struct(child);
  77         read_unlock(&tasklist_lock);
  78         if (!child)
  79                 goto out;
  80
  81         ret = -EPERM;
  82         if (pid == 1)           /* you may not mess with init */
  83                 goto out_tsk;
  84
  85         if (request == PTRACE_ATTACH) {
  86                 ret = ptrace_attach(child);
  87                 goto out_tsk;
  88         }
  89
  90         ret = ptrace_check_attach(child, request == PTRACE_KILL);
  91         if (ret < 0)
  92                 goto out_tsk;
  93
  94         switch (request) {
  95         /* when I and D space are separate, these will need to be fixed. */
  96         case PTRACE_PEEKTEXT: /* read word at location addr. */
  97         case PTRACE_PEEKDATA: {
  98                 unsigned long tmp;
  99                 int copied;
 100
 101                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 102                 ret = -EIO;
 103                 if (copied != sizeof(tmp))
 104                         break;
 105                 ret = put_user(tmp,(unsigned long __user *) data);
 106                 break;
 107         }
 108
 109         /* read the word at location addr in the USER area. */
 110         case PTRACE_PEEKUSR: {
 111                 unsigned long index;
 112                 unsigned long tmp;
 113
 114                 ret = -EIO;
 115                 /* convert to index and check */
 116                 index = (unsigned long) addr >> 3;
 117                 if ((addr & 7) || (index > PT_FPSCR))
 118                         break;
 119
 120                 if (index < PT_FPR0) {
 121                         tmp = get_reg(child, (int)index);
 122                 } else {
 123                         flush_fp_to_thread(child);
 124                         tmp = ((unsigned long *)child->thread.fpr)[index - PT_FPR0];
 125                 }
 126                 ret = put_user(tmp,(unsigned long __user *) data);
 127                 break;
 128         }
 129
 130         /* If I and D space are separate, this will have to be fixed. */
 131         case PTRACE_POKETEXT: /* write the word at location addr. */
 132         case PTRACE_POKEDATA:
 133                 ret = 0;
 134                 if (access_process_vm(child, addr, &data, sizeof(data), 1)
 135                                 == sizeof(data))
 136                         break;
 137                 ret = -EIO;
 138                 break;
 139
 140         /* write the word at location addr in the USER area */
 141         case PTRACE_POKEUSR: {
 142                 unsigned long index;
 143
 144                 ret = -EIO;
 145                 /* convert to index and check */
 146                 index = (unsigned long) addr >> 3;
 147                 if ((addr & 7) || (index > PT_FPSCR))
 148                         break;
 149
 150                 if (index == PT_ORIG_R3)
 151                         break;
 152                 if (index < PT_FPR0) {
 153                         ret = put_reg(child, index, data);
 154                 } else {
 155                         flush_fp_to_thread(child);
 156                         ((unsigned long *)child->thread.fpr)[index - PT_FPR0] = data;
 157                         ret = 0;
 158                 }
 159                 break;
 160         }
 161
 162         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 163         case PTRACE_CONT: { /* restart after signal. */
 164                 ret = -EIO;
 165                 if ((unsigned long) data > _NSIG)
 166                         break;
 167                 if (request == PTRACE_SYSCALL)
 168                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 169                 else
 170                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 171                 child->exit_code = data;
 172                 /* make sure the single step bit is not set. */
 173                 clear_single_step(child);
 174                 wake_up_process(child);
 175                 ret = 0;
 176                 break;
 177         }
 178
 179         /*
 180          * make the child exit.  Best I can do is send it a sigkill.
 181          * perhaps it should be put in the status that it wants to
 182          * exit.
 183          */
 184         case PTRACE_KILL: {
 185                 ret = 0;
 186                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 187                         break;
 188                 child->exit_code = SIGKILL;
 189                 /* make sure the single step bit is not set. */
 190                 clear_single_step(child);
 191                 wake_up_process(child);
 192                 break;
 193         }
 194
 195         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 196                 ret = -EIO;
 197                 if ((unsigned long) data > _NSIG)
 198                         break;
 199                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 200                 set_single_step(child);
 201                 child->exit_code = data;
 202                 /* give it a chance to run. */
 203                 wake_up_process(child);
 204                 ret = 0;
 205                 break;
 206         }
 207
 208         case PTRACE_DETACH:
 209                 ret = ptrace_detach(child, data);
 210                 break;
 211
 212         case PPC_PTRACE_GETREGS: { /* Get GPRs 0 - 31. */
 213                 int i;
 214                 unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
 215                 unsigned long __user *tmp = (unsigned long __user *)addr;
 216
 217                 for (i = 0; i < 32; i++) {
 218                         ret = put_user(*reg, tmp);
 219                         if (ret)
 220                                 break;
 221                         reg++;
 222                         tmp++;
 223                 }
 224                 break;
 225         }
 226
 227         case PPC_PTRACE_SETREGS: { /* Set GPRs 0 - 31. */
 228                 int i;
 229                 unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
 230                 unsigned long __user *tmp = (unsigned long __user *)addr;
 231
 232                 for (i = 0; i < 32; i++) {
 233                         ret = get_user(*reg, tmp);
 234                         if (ret)
 235                                 break;
 236                         reg++;
 237                         tmp++;
 238                 }
 239                 break;
 240         }
 241
 242         case PPC_PTRACE_GETFPREGS: { /* Get FPRs 0 - 31. */
 243                 int i;
 244                 unsigned long *reg = &((unsigned long *)child->thread.fpr)[0];
 245                 unsigned long __user *tmp = (unsigned long __user *)addr;
 246
 247                 flush_fp_to_thread(child);
 248
 249                 for (i = 0; i < 32; i++) {
 250                         ret = put_user(*reg, tmp);
 251                         if (ret)
 252                                 break;
 253                         reg++;
 254                         tmp++;
 255                 }
 256                 break;
 257         }
 258
 259         case PPC_PTRACE_SETFPREGS: { /* Get FPRs 0 - 31. */
 260                 int i;
 261                 unsigned long *reg = &((unsigned long *)child->thread.fpr)[0];
 262                 unsigned long __user *tmp = (unsigned long __user *)addr;
 263
 264                 flush_fp_to_thread(child);
 265
 266                 for (i = 0; i < 32; i++) {
 267                         ret = get_user(*reg, tmp);
 268                         if (ret)
 269                                 break;
 270                         reg++;
 271                         tmp++;
 272                 }
 273                 break;
 274         }
 275
 276         default:
 277                 ret = ptrace_request(child, request, addr, data);
 278                 break;
 279         }
 280 out_tsk:
 281         put_task_struct(child);
 282 out:
 283         unlock_kernel();
 284         return ret;
 285 }
 286
 287 static void do_syscall_trace(void)
 288 {
 289         /* the 0x80 provides a way for the tracing parent to distinguish
 290            between a syscall stop and SIGTRAP delivery */
 291         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 292                                  ? 0x80 : 0));
 293
 294         /*
 295          * this isn't the same as continuing with a signal, but it will do
 296          * for normal use.  strace only continues with a signal if the
 297          * stopping signal is not SIGTRAP.  -brl
 298          */
 299         if (current->exit_code) {
 300                 send_sig(current->exit_code, current, 1);
 301                 current->exit_code = 0;
 302         }
 303 }
 304
 305 void do_syscall_trace_enter(struct pt_regs *regs)
 306 {
 307         if (unlikely(current->audit_context))
 308                 audit_syscall_entry(current, regs->gpr[0],
 309                                     regs->gpr[3], regs->gpr[4],
 310                                     regs->gpr[5], regs->gpr[6]);
 311
 312         if (test_thread_flag(TIF_SYSCALL_TRACE)
 313             && (current->ptrace & PT_PTRACED))
 314                 do_syscall_trace();
 315 }
 316
 317 void do_syscall_trace_leave(struct pt_regs *regs)
 318 {
 319         secure_computing(regs->gpr[0]);
 320
 321         if (unlikely(current->audit_context))
 322                 audit_syscall_exit(current, regs->result);
 323
 324         if ((test_thread_flag(TIF_SYSCALL_TRACE)
 325              || test_thread_flag(TIF_SINGLESTEP))
 326             && (current->ptrace & PT_PTRACED))
 327                 do_syscall_trace();
 328 }