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 #include <linux/signal.h>
  32
  33 #include <asm/uaccess.h>
  34 #include <asm/page.h>
  35 #include <asm/pgtable.h>
  36 #include <asm/system.h>
  37 #include <asm/ptrace-common.h>
  38
  39 /*
  40  * does not yet catch signals sent when the child dies.
  41  * in exit.c or in signal.c.
  42  */
  43
  44 /*
  45  * Called by kernel/ptrace.c when detaching..
  46  *
  47  * Make sure single step bits etc are not set.
  48  */
  49 void ptrace_disable(struct task_struct *child)
  50 {
  51         /* make sure the single step bit is not set. */
  52         clear_single_step(child);
  53 }
  54
  55 int sys_ptrace(long request, long pid, long addr, long data)
  56 {
  57         struct task_struct *child;
  58         int ret = -EPERM;
  59
  60         lock_kernel();
  61         if (request == PTRACE_TRACEME) {
  62                 /* are we already being traced? */
  63                 if (current->ptrace & PT_PTRACED)
  64                         goto out;
  65                 ret = security_ptrace(current->parent, current);
  66                 if (ret)
  67                         goto out;
  68                 /* set the ptrace bit in the process flags. */
  69                 current->ptrace |= PT_PTRACED;
  70                 ret = 0;
  71                 goto out;
  72         }
  73         ret = -ESRCH;
  74         read_lock(&tasklist_lock);
  75         child = find_task_by_pid(pid);
  76         if (child)
  77                 get_task_struct(child);
  78         read_unlock(&tasklist_lock);
  79         if (!child)
  80                 goto out;
  81
  82         ret = -EPERM;
  83         if (pid == 1)           /* you may not mess with init */
  84                 goto out_tsk;
  85
  86         if (request == PTRACE_ATTACH) {
  87                 ret = ptrace_attach(child);
  88                 goto out_tsk;
  89         }
  90
  91         ret = ptrace_check_attach(child, request == PTRACE_KILL);
  92         if (ret < 0)
  93                 goto out_tsk;
  94
  95         switch (request) {
  96         /* when I and D space are separate, these will need to be fixed. */
  97         case PTRACE_PEEKTEXT: /* read word at location addr. */
  98         case PTRACE_PEEKDATA: {
  99                 unsigned long tmp;
 100                 int copied;
 101
 102                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 103                 ret = -EIO;
 104                 if (copied != sizeof(tmp))
 105                         break;
 106                 ret = put_user(tmp,(unsigned long __user *) data);
 107                 break;
 108         }
 109
 110         /* read the word at location addr in the USER area. */
 111         case PTRACE_PEEKUSR: {
 112                 unsigned long index;
 113                 unsigned long tmp;
 114
 115                 ret = -EIO;
 116                 /* convert to index and check */
 117                 index = (unsigned long) addr >> 3;
 118                 if ((addr & 7) || (index > PT_FPSCR))
 119                         break;
 120
 121                 if (index < PT_FPR0) {
 122                         tmp = get_reg(child, (int)index);
 123                 } else {
 124                         flush_fp_to_thread(child);
 125                         tmp = ((unsigned long *)child->thread.fpr)[index - PT_FPR0];
 126                 }
 127                 ret = put_user(tmp,(unsigned long __user *) data);
 128                 break;
 129         }
 130
 131         /* If I and D space are separate, this will have to be fixed. */
 132         case PTRACE_POKETEXT: /* write the word at location addr. */
 133         case PTRACE_POKEDATA:
 134                 ret = 0;
 135                 if (access_process_vm(child, addr, &data, sizeof(data), 1)
 136                                 == sizeof(data))
 137                         break;
 138                 ret = -EIO;
 139                 break;
 140
 141         /* write the word at location addr in the USER area */
 142         case PTRACE_POKEUSR: {
 143                 unsigned long index;
 144
 145                 ret = -EIO;
 146                 /* convert to index and check */
 147                 index = (unsigned long) addr >> 3;
 148                 if ((addr & 7) || (index > PT_FPSCR))
 149                         break;
 150
 151                 if (index == PT_ORIG_R3)
 152                         break;
 153                 if (index < PT_FPR0) {
 154                         ret = put_reg(child, index, data);
 155                 } else {
 156                         flush_fp_to_thread(child);
 157                         ((unsigned long *)child->thread.fpr)[index - PT_FPR0] = data;
 158                         ret = 0;
 159                 }
 160                 break;
 161         }
 162
 163         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 164         case PTRACE_CONT: { /* restart after signal. */
 165                 ret = -EIO;
 166                 if (!valid_signal(data))
 167                         break;
 168                 if (request == PTRACE_SYSCALL)
 169                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 170                 else
 171                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 172                 child->exit_code = data;
 173                 /* make sure the single step bit is not set. */
 174                 clear_single_step(child);
 175                 wake_up_process(child);
 176                 ret = 0;
 177                 break;
 178         }
 179
 180         /*
 181          * make the child exit.  Best I can do is send it a sigkill.
 182          * perhaps it should be put in the status that it wants to
 183          * exit.
 184          */
 185         case PTRACE_KILL: {
 186                 ret = 0;
 187                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 188                         break;
 189                 child->exit_code = SIGKILL;
 190                 /* make sure the single step bit is not set. */
 191                 clear_single_step(child);
 192                 wake_up_process(child);
 193                 break;
 194         }
 195
 196         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 197                 ret = -EIO;
 198                 if (!valid_signal(data))
 199                         break;
 200                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 201                 set_single_step(child);
 202                 child->exit_code = data;
 203                 /* give it a chance to run. */
 204                 wake_up_process(child);
 205                 ret = 0;
 206                 break;
 207         }
 208
 209         case PTRACE_DETACH:
 210                 ret = ptrace_detach(child, data);
 211                 break;
 212
 213         case PPC_PTRACE_GETREGS: { /* Get GPRs 0 - 31. */
 214                 int i;
 215                 unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
 216                 unsigned long __user *tmp = (unsigned long __user *)addr;
 217
 218                 for (i = 0; i < 32; i++) {
 219                         ret = put_user(*reg, tmp);
 220                         if (ret)
 221                                 break;
 222                         reg++;
 223                         tmp++;
 224                 }
 225                 break;
 226         }
 227
 228         case PPC_PTRACE_SETREGS: { /* Set GPRs 0 - 31. */
 229                 int i;
 230                 unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
 231                 unsigned long __user *tmp = (unsigned long __user *)addr;
 232
 233                 for (i = 0; i < 32; i++) {
 234                         ret = get_user(*reg, tmp);
 235                         if (ret)
 236                                 break;
 237                         reg++;
 238                         tmp++;
 239                 }
 240                 break;
 241         }
 242
 243         case PPC_PTRACE_GETFPREGS: { /* Get FPRs 0 - 31. */
 244                 int i;
 245                 unsigned long *reg = &((unsigned long *)child->thread.fpr)[0];
 246                 unsigned long __user *tmp = (unsigned long __user *)addr;
 247
 248                 flush_fp_to_thread(child);
 249
 250                 for (i = 0; i < 32; i++) {
 251                         ret = put_user(*reg, tmp);
 252                         if (ret)
 253                                 break;
 254                         reg++;
 255                         tmp++;
 256                 }
 257                 break;
 258         }
 259
 260         case PPC_PTRACE_SETFPREGS: { /* Get FPRs 0 - 31. */
 261                 int i;
 262                 unsigned long *reg = &((unsigned long *)child->thread.fpr)[0];
 263                 unsigned long __user *tmp = (unsigned long __user *)addr;
 264
 265                 flush_fp_to_thread(child);
 266
 267                 for (i = 0; i < 32; i++) {
 268                         ret = get_user(*reg, tmp);
 269                         if (ret)
 270                                 break;
 271                         reg++;
 272                         tmp++;
 273                 }
 274                 break;
 275         }
 276
 277         default:
 278                 ret = ptrace_request(child, request, addr, data);
 279                 break;
 280         }
 281 out_tsk:
 282         put_task_struct(child);
 283 out:
 284         unlock_kernel();
 285         return ret;
 286 }
 287
 288 static void do_syscall_trace(void)
 289 {
 290         /* the 0x80 provides a way for the tracing parent to distinguish
 291            between a syscall stop and SIGTRAP delivery */
 292         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 293                                  ? 0x80 : 0));
 294
 295         /*
 296          * this isn't the same as continuing with a signal, but it will do
 297          * for normal use.  strace only continues with a signal if the
 298          * stopping signal is not SIGTRAP.  -brl
 299          */
 300         if (current->exit_code) {
 301                 send_sig(current->exit_code, current, 1);
 302                 current->exit_code = 0;
 303         }
 304 }
 305
 306 void do_syscall_trace_enter(struct pt_regs *regs)
 307 {
 308         if (unlikely(current->audit_context))
 309                 audit_syscall_entry(current, regs->gpr[0],
 310                                     regs->gpr[3], regs->gpr[4],
 311                                     regs->gpr[5], regs->gpr[6]);
 312
 313         if (test_thread_flag(TIF_SYSCALL_TRACE)
 314             && (current->ptrace & PT_PTRACED))
 315                 do_syscall_trace();
 316 }
 317
 318 void do_syscall_trace_leave(struct pt_regs *regs)
 319 {
 320         secure_computing(regs->gpr[0]);
 321
 322         if (unlikely(current->audit_context))
 323                 audit_syscall_exit(current, regs->result);
 324
 325         if ((test_thread_flag(TIF_SYSCALL_TRACE)
 326              || test_thread_flag(TIF_SINGLESTEP))
 327             && (current->ptrace & PT_PTRACED))
 328                 do_syscall_trace();
 329 }