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/config.h>
  21 #include <linux/kernel.h>
  22 #include <linux/sched.h>
  23 #include <linux/mm.h>
  24 #include <linux/smp.h>
  25 #include <linux/smp_lock.h>
  26 #include <linux/errno.h>
  27 #include <linux/ptrace.h>
  28 #include <linux/user.h>
  29 #include <linux/security.h>
  30 #include <linux/audit.h>
  31 #include <linux/seccomp.h>
  32 #include <linux/signal.h>
  33
  34 #include <asm/uaccess.h>
  35 #include <asm/page.h>
  36 #include <asm/pgtable.h>
  37 #include <asm/system.h>
  38 #include <asm/ptrace-common.h>
  39
  40 /*
  41  * does not yet catch signals sent when the child dies.
  42  * in exit.c or in signal.c.
  43  */
  44
  45 /*
  46  * Called by kernel/ptrace.c when detaching..
  47  *
  48  * Make sure single step bits etc are not set.
  49  */
  50 void ptrace_disable(struct task_struct *child)
  51 {
  52         /* make sure the single step bit is not set. */
  53         clear_single_step(child);
  54 }
  55
  56 int sys_ptrace(long request, long pid, long addr, long data)
  57 {
  58         struct task_struct *child;
  59         int ret = -EPERM;
  60
  61         lock_kernel();
  62         if (request == PTRACE_TRACEME) {
  63                 /* are we already being traced? */
  64                 if (current->ptrace & PT_PTRACED)
  65                         goto out;
  66                 ret = security_ptrace(current->parent, current);
  67                 if (ret)
  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                 unsigned long index;
 114                 unsigned long tmp;
 115
 116                 ret = -EIO;
 117                 /* convert to index and check */
 118                 index = (unsigned long) addr >> 3;
 119                 if ((addr & 7) || (index > PT_FPSCR))
 120                         break;
 121
 122                 if (index < PT_FPR0) {
 123                         tmp = get_reg(child, (int)index);
 124                 } else {
 125                         flush_fp_to_thread(child);
 126                         tmp = ((unsigned long *)child->thread.fpr)[index - PT_FPR0];
 127                 }
 128                 ret = put_user(tmp,(unsigned long __user *) data);
 129                 break;
 130         }
 131
 132         /* If I and D space are separate, this will have to be fixed. */
 133         case PTRACE_POKETEXT: /* write the word at location addr. */
 134         case PTRACE_POKEDATA:
 135                 ret = 0;
 136                 if (access_process_vm(child, addr, &data, sizeof(data), 1)
 137                                 == sizeof(data))
 138                         break;
 139                 ret = -EIO;
 140                 break;
 141
 142         /* write the word at location addr in the USER area */
 143         case PTRACE_POKEUSR: {
 144                 unsigned long index;
 145
 146                 ret = -EIO;
 147                 /* convert to index and check */
 148                 index = (unsigned long) addr >> 3;
 149                 if ((addr & 7) || (index > PT_FPSCR))
 150                         break;
 151
 152                 if (index == PT_ORIG_R3)
 153                         break;
 154                 if (index < PT_FPR0) {
 155                         ret = put_reg(child, index, data);
 156                 } else {
 157                         flush_fp_to_thread(child);
 158                         ((unsigned long *)child->thread.fpr)[index - PT_FPR0] = data;
 159                         ret = 0;
 160                 }
 161                 break;
 162         }
 163
 164         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 165         case PTRACE_CONT: { /* restart after signal. */
 166                 ret = -EIO;
 167                 if (!valid_signal(data))
 168                         break;
 169                 if (request == PTRACE_SYSCALL)
 170                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 171                 else
 172                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 173                 child->exit_code = data;
 174                 /* make sure the single step bit is not set. */
 175                 clear_single_step(child);
 176                 wake_up_process(child);
 177                 ret = 0;
 178                 break;
 179         }
 180
 181         /*
 182          * make the child exit.  Best I can do is send it a sigkill.
 183          * perhaps it should be put in the status that it wants to
 184          * exit.
 185          */
 186         case PTRACE_KILL: {
 187                 ret = 0;
 188                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 189                         break;
 190                 child->exit_code = SIGKILL;
 191                 /* make sure the single step bit is not set. */
 192                 clear_single_step(child);
 193                 wake_up_process(child);
 194                 break;
 195         }
 196
 197         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 198                 ret = -EIO;
 199                 if (!valid_signal(data))
 200                         break;
 201                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 202                 set_single_step(child);
 203                 child->exit_code = data;
 204                 /* give it a chance to run. */
 205                 wake_up_process(child);
 206                 ret = 0;
 207                 break;
 208         }
 209
 210         case PTRACE_GET_DEBUGREG: {
 211                 ret = -EINVAL;
 212                 /* We only support one DABR and no IABRS at the moment */
 213                 if (addr > 0)
 214                         break;
 215                 ret = put_user(child->thread.dabr,
 216                                (unsigned long __user *)data);
 217                 break;
 218         }
 219
 220         case PTRACE_SET_DEBUGREG:
 221                 ret = ptrace_set_debugreg(child, addr, data);
 222
 223         case PTRACE_DETACH:
 224                 ret = ptrace_detach(child, data);
 225                 break;
 226
 227         case PPC_PTRACE_GETREGS: { /* Get 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 = put_user(*reg, tmp);
 234                         if (ret)
 235                                 break;
 236                         reg++;
 237                         tmp++;
 238                 }
 239                 break;
 240         }
 241
 242         case PPC_PTRACE_SETREGS: { /* Set GPRs 0 - 31. */
 243                 int i;
 244                 unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
 245                 unsigned long __user *tmp = (unsigned long __user *)addr;
 246
 247                 for (i = 0; i < 32; i++) {
 248                         ret = get_user(*reg, tmp);
 249                         if (ret)
 250                                 break;
 251                         reg++;
 252                         tmp++;
 253                 }
 254                 break;
 255         }
 256
 257         case PPC_PTRACE_GETFPREGS: { /* Get FPRs 0 - 31. */
 258                 int i;
 259                 unsigned long *reg = &((unsigned long *)child->thread.fpr)[0];
 260                 unsigned long __user *tmp = (unsigned long __user *)addr;
 261
 262                 flush_fp_to_thread(child);
 263
 264                 for (i = 0; i < 32; i++) {
 265                         ret = put_user(*reg, tmp);
 266                         if (ret)
 267                                 break;
 268                         reg++;
 269                         tmp++;
 270                 }
 271                 break;
 272         }
 273
 274         case PPC_PTRACE_SETFPREGS: { /* Get FPRs 0 - 31. */
 275                 int i;
 276                 unsigned long *reg = &((unsigned long *)child->thread.fpr)[0];
 277                 unsigned long __user *tmp = (unsigned long __user *)addr;
 278
 279                 flush_fp_to_thread(child);
 280
 281                 for (i = 0; i < 32; i++) {
 282                         ret = get_user(*reg, tmp);
 283                         if (ret)
 284                                 break;
 285                         reg++;
 286                         tmp++;
 287                 }
 288                 break;
 289         }
 290
 291 #ifdef CONFIG_ALTIVEC
 292         case PTRACE_GETVRREGS:
 293                 /* Get the child altivec register state. */
 294                 flush_altivec_to_thread(child);
 295                 ret = get_vrregs((unsigned long __user *)data, child);
 296                 break;
 297
 298         case PTRACE_SETVRREGS:
 299                 /* Set the child altivec register state. */
 300                 flush_altivec_to_thread(child);
 301                 ret = set_vrregs(child, (unsigned long __user *)data);
 302                 break;
 303 #endif
 304
 305         default:
 306                 ret = ptrace_request(child, request, addr, data);
 307                 break;
 308         }
 309 out_tsk:
 310         put_task_struct(child);
 311 out:
 312         unlock_kernel();
 313         return ret;
 314 }
 315
 316 static void do_syscall_trace(void)
 317 {
 318         /* the 0x80 provides a way for the tracing parent to distinguish
 319            between a syscall stop and SIGTRAP delivery */
 320         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 321                                  ? 0x80 : 0));
 322
 323         /*
 324          * this isn't the same as continuing with a signal, but it will do
 325          * for normal use.  strace only continues with a signal if the
 326          * stopping signal is not SIGTRAP.  -brl
 327          */
 328         if (current->exit_code) {
 329                 send_sig(current->exit_code, current, 1);
 330                 current->exit_code = 0;
 331         }
 332 }
 333
 334 void do_syscall_trace_enter(struct pt_regs *regs)
 335 {
 336         secure_computing(regs->gpr[0]);
 337
 338         if (test_thread_flag(TIF_SYSCALL_TRACE)
 339             && (current->ptrace & PT_PTRACED))
 340                 do_syscall_trace();
 341
 342         if (unlikely(current->audit_context))
 343                 audit_syscall_entry(current,
 344                                     test_thread_flag(TIF_32BIT)?AUDIT_ARCH_PPC:AUDIT_ARCH_PPC64,
 345                                     regs->gpr[0],
 346                                     regs->gpr[3], regs->gpr[4],
 347                                     regs->gpr[5], regs->gpr[6]);
 348
 349 }
 350
 351 void do_syscall_trace_leave(struct pt_regs *regs)
 352 {
 353         if (unlikely(current->audit_context))
 354                 audit_syscall_exit(current,
 355                                    (regs->ccr&0x1000)?AUDITSC_FAILURE:AUDITSC_SUCCESS,
 356                                    regs->result);
 357
 358         if ((test_thread_flag(TIF_SYSCALL_TRACE)
 359              || test_thread_flag(TIF_SINGLESTEP))
 360             && (current->ptrace & PT_PTRACED))
 361                 do_syscall_trace();
 362 }