arch/xtensa/kernel/ptrace.c

   1 // TODO some minor issues
   2 /*
   3  * This file is subject to the terms and conditions of the GNU General Public
   4  * License.  See the file "COPYING" in the main directory of this archive
   5  * for more details.
   6  *
   7  * Copyright (C) 2001 - 2005  Tensilica Inc.
   8  *
   9  * Joe Taylor   <joe@tensilica.com, joetylr@yahoo.com>
  10  * Chris Zankel <chris@zankel.net>
  11  * Scott Foehner<sfoehner@yahoo.com>,
  12  * Kevin Chea
  13  * Marc Gauthier<marc@tensilica.com> <marc@alumni.uwaterloo.ca>
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/sched.h>
  18 #include <linux/mm.h>
  19 #include <linux/errno.h>
  20 #include <linux/ptrace.h>
  21 #include <linux/smp.h>
  22 #include <linux/security.h>
  23 #include <linux/signal.h>
  24
  25 #include <asm/pgtable.h>
  26 #include <asm/page.h>
  27 #include <asm/system.h>
  28 #include <asm/uaccess.h>
  29 #include <asm/ptrace.h>
  30 #include <asm/elf.h>
  31
  32 #define TEST_KERNEL     // verify kernel operations FIXME: remove
  33
  34
  35 /*
  36  * Called by kernel/ptrace.c when detaching..
  37  *
  38  * Make sure single step bits etc are not set.
  39  */
  40
  41 void ptrace_disable(struct task_struct *child)
  42 {
  43         /* Nothing to do.. */
  44 }
  45
  46 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
  47 {
  48         int ret = -EPERM;
  49
  50         switch (request) {
  51         case PTRACE_PEEKTEXT: /* read word at location addr. */
  52         case PTRACE_PEEKDATA:
  53                 ret = generic_ptrace_peekdata(child, addr, data);
  54                 goto out;
  55
  56         /* Read the word at location addr in the USER area.  */
  57
  58         case PTRACE_PEEKUSR:
  59                 {
  60                 struct pt_regs *regs;
  61                 unsigned long tmp;
  62
  63                 regs = task_pt_regs(child);
  64                 tmp = 0;  /* Default return value. */
  65
  66                 switch(addr) {
  67
  68                 case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1:
  69                         {
  70                         int ar = addr - REG_AR_BASE - regs->windowbase * 4;
  71                         ar &= (XCHAL_NUM_AREGS - 1);
  72                         if (ar < 16 && ar + (regs->wmask >> 4) * 4 >= 0)
  73                                 tmp = regs->areg[ar];
  74                         else
  75                                 ret = -EIO;
  76                         break;
  77                         }
  78                 case REG_A_BASE ... REG_A_BASE + 15:
  79                         tmp = regs->areg[addr - REG_A_BASE];
  80                         break;
  81                 case REG_PC:
  82                         tmp = regs->pc;
  83                         break;
  84                 case REG_PS:
  85                         /* Note:  PS.EXCM is not set while user task is running;
  86                          * its being set in regs is for exception handling
  87                          * convenience.  */
  88                         tmp = (regs->ps & ~(1 << PS_EXCM_BIT));
  89                         break;
  90                 case REG_WB:
  91                         tmp = regs->windowbase;
  92                         break;
  93                 case REG_WS:
  94                         tmp = regs->windowstart;
  95                         break;
  96                 case REG_LBEG:
  97                         tmp = regs->lbeg;
  98                         break;
  99                 case REG_LEND:
 100                         tmp = regs->lend;
 101                         break;
 102                 case REG_LCOUNT:
 103                         tmp = regs->lcount;
 104                         break;
 105                 case REG_SAR:
 106                         tmp = regs->sar;
 107                         break;
 108                 case REG_DEPC:
 109                         tmp = regs->depc;
 110                         break;
 111                 case REG_EXCCAUSE:
 112                         tmp = regs->exccause;
 113                         break;
 114                 case REG_EXCVADDR:
 115                         tmp = regs->excvaddr;
 116                         break;
 117                 case SYSCALL_NR:
 118                         tmp = regs->syscall;
 119                         break;
 120                 default:
 121                         tmp = 0;
 122                         ret = -EIO;
 123                         goto out;
 124                 }
 125                 ret = put_user(tmp, (unsigned long *) data);
 126                 goto out;
 127                 }
 128
 129         case PTRACE_POKETEXT: /* write the word at location addr. */
 130         case PTRACE_POKEDATA:
 131                 if (access_process_vm(child, addr, &data, sizeof(data), 1)
 132                     == sizeof(data))
 133                         break;
 134                 ret = -EIO;
 135                 goto out;
 136
 137         case PTRACE_POKEUSR:
 138                 {
 139                 struct pt_regs *regs;
 140                 regs = task_pt_regs(child);
 141
 142                 switch (addr) {
 143                 case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1:
 144                         {
 145                         int ar = addr - REG_AR_BASE - regs->windowbase * 4;
 146                         if (ar < 16 && ar + (regs->wmask >> 4) * 4 >= 0)
 147                                 regs->areg[ar & (XCHAL_NUM_AREGS - 1)] = data;
 148                         else
 149                                 ret = -EIO;
 150                         break;
 151                         }
 152                 case REG_A_BASE ... REG_A_BASE + 15:
 153                         regs->areg[addr - REG_A_BASE] = data;
 154                         break;
 155                 case REG_PC:
 156                         regs->pc = data;
 157                         break;
 158                 case SYSCALL_NR:
 159                         regs->syscall = data;
 160                         break;
 161 #ifdef TEST_KERNEL
 162                 case REG_WB:
 163                         regs->windowbase = data;
 164                         break;
 165                 case REG_WS:
 166                         regs->windowstart = data;
 167                         break;
 168 #endif
 169
 170                 default:
 171                         /* The rest are not allowed. */
 172                         ret = -EIO;
 173                         break;
 174                 }
 175                 break;
 176                 }
 177
 178         /* continue and stop at next (return from) syscall */
 179         case PTRACE_SYSCALL:
 180         case PTRACE_CONT: /* restart after signal. */
 181         {
 182                 ret = -EIO;
 183                 if (!valid_signal(data))
 184                         break;
 185                 if (request == PTRACE_SYSCALL)
 186                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 187                 else
 188                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 189                 child->exit_code = data;
 190                 /* Make sure the single step bit is not set. */
 191                 child->ptrace &= ~PT_SINGLESTEP;
 192                 wake_up_process(child);
 193                 ret = 0;
 194                 break;
 195         }
 196
 197         /*
 198          * make the child exit.  Best I can do is send it a sigkill.
 199          * perhaps it should be put in the status that it wants to
 200          * exit.
 201          */
 202         case PTRACE_KILL:
 203                 ret = 0;
 204                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 205                         break;
 206                 child->exit_code = SIGKILL;
 207                 child->ptrace &= ~PT_SINGLESTEP;
 208                 wake_up_process(child);
 209                 break;
 210
 211         case PTRACE_SINGLESTEP:
 212                 ret = -EIO;
 213                 if (!valid_signal(data))
 214                         break;
 215                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 216                 child->ptrace |= PT_SINGLESTEP;
 217                 child->exit_code = data;
 218                 wake_up_process(child);
 219                 ret = 0;
 220                 break;
 221
 222         case PTRACE_GETREGS:
 223         {
 224                 /* 'data' points to user memory in which to write.
 225                  * Mainly due to the non-live register values, we
 226                  * reformat the register values into something more
 227                  * standard.  For convenience, we use the handy
 228                  * elf_gregset_t format. */
 229
 230                 xtensa_gregset_t format;
 231                 struct pt_regs *regs = task_pt_regs(child);
 232
 233                 do_copy_regs (&format, regs, child);
 234
 235                 /* Now, copy to user space nice and easy... */
 236                 ret = 0;
 237                 if (copy_to_user((void *)data, &format, sizeof(elf_gregset_t)))
 238                         ret = -EFAULT;
 239                 break;
 240         }
 241
 242         case PTRACE_SETREGS:
 243         {
 244                 /* 'data' points to user memory that contains the new
 245                  * values in the elf_gregset_t format. */
 246
 247                 xtensa_gregset_t format;
 248                 struct pt_regs *regs = task_pt_regs(child);
 249
 250                 if (copy_from_user(&format,(void *)data,sizeof(elf_gregset_t))){
 251                         ret = -EFAULT;
 252                         break;
 253                 }
 254
 255                 /* FIXME: Perhaps we want some sanity checks on
 256                  * these user-space values?  See ARM version.  Are
 257                  * debuggers a security concern? */
 258
 259                 do_restore_regs (&format, regs, child);
 260
 261                 ret = 0;
 262                 break;
 263         }
 264
 265         case PTRACE_GETFPREGS:
 266         {
 267                 /* 'data' points to user memory in which to write.
 268                  * For convenience, we use the handy
 269                  * elf_fpregset_t format. */
 270
 271                 elf_fpregset_t fpregs;
 272                 struct pt_regs *regs = task_pt_regs(child);
 273
 274                 do_save_fpregs (&fpregs, regs, child);
 275
 276                 /* Now, copy to user space nice and easy... */
 277                 ret = 0;
 278                 if (copy_to_user((void *)data, &fpregs, sizeof(elf_fpregset_t)))
 279                         ret = -EFAULT;
 280
 281                 break;
 282         }
 283
 284         case PTRACE_SETFPREGS:
 285         {
 286                 /* 'data' points to user memory that contains the new
 287                  * values in the elf_fpregset_t format.
 288                  */
 289                 elf_fpregset_t fpregs;
 290                 struct pt_regs *regs = task_pt_regs(child);
 291
 292                 ret = 0;
 293                 if (copy_from_user(&fpregs, (void *)data, sizeof(elf_fpregset_t))) {
 294                         ret = -EFAULT;
 295                         break;
 296                 }
 297
 298                 if (do_restore_fpregs (&fpregs, regs, child))
 299                         ret = -EIO;
 300                 break;
 301         }
 302
 303         case PTRACE_GETFPREGSIZE:
 304                 /* 'data' points to 'unsigned long' set to the size
 305                  * of elf_fpregset_t
 306                  */
 307                 ret = put_user(sizeof(elf_fpregset_t), (unsigned long *) data);
 308                 break;
 309
 310         case PTRACE_DETACH: /* detach a process that was attached. */
 311                 ret = ptrace_detach(child, data);
 312                 break;
 313
 314         default:
 315                 ret = ptrace_request(child, request, addr, data);
 316                 goto out;
 317         }
 318  out:
 319         return ret;
 320 }
 321
 322 void do_syscall_trace(void)
 323 {
 324         /*
 325          * The 0x80 provides a way for the tracing parent to distinguish
 326          * between a syscall stop and SIGTRAP delivery
 327          */
 328         ptrace_notify(SIGTRAP|((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));
 329
 330         /*
 331          * this isn't the same as continuing with a signal, but it will do
 332          * for normal use.  strace only continues with a signal if the
 333          * stopping signal is not SIGTRAP.  -brl
 334          */
 335         if (current->exit_code) {
 336                 send_sig(current->exit_code, current, 1);
 337                 current->exit_code = 0;
 338         }
 339 }
 340
 341 void do_syscall_trace_enter(struct pt_regs *regs)
 342 {
 343         if (test_thread_flag(TIF_SYSCALL_TRACE)
 344                         && (current->ptrace & PT_PTRACED))
 345                 do_syscall_trace();
 346
 347 #if 0
 348         if (unlikely(current->audit_context))
 349                 audit_syscall_entry(current, AUDIT_ARCH_XTENSA..);
 350 #endif
 351 }
 352
 353 void do_syscall_trace_leave(struct pt_regs *regs)
 354 {
 355         if ((test_thread_flag(TIF_SYSCALL_TRACE))
 356                         && (current->ptrace & PT_PTRACED))
 357                 do_syscall_trace();
 358 }
 359