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 - 2007  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 #include <asm/coprocessor.h>
  32
  33 /*
  34  * Called by kernel/ptrace.c when detaching to disable single stepping.
  35  */
  36
  37 void ptrace_disable(struct task_struct *child)
  38 {
  39         /* Nothing to do.. */
  40 }
  41
  42 int ptrace_getregs(struct task_struct *child, void __user *uregs)
  43 {
  44         struct pt_regs *regs = task_pt_regs(child);
  45         xtensa_gregset_t __user *gregset = uregs;
  46         unsigned long wm = regs->wmask;
  47         unsigned long wb = regs->windowbase;
  48         int live, i;
  49
  50         if (!access_ok(VERIFY_WRITE, uregs, sizeof(xtensa_gregset_t)))
  51                 return -EIO;
  52
  53         __put_user(regs->pc, &gregset->pc);
  54         __put_user(regs->ps & ~(1 << PS_EXCM_BIT), &gregset->ps);
  55         __put_user(regs->lbeg, &gregset->lbeg);
  56         __put_user(regs->lend, &gregset->lend);
  57         __put_user(regs->lcount, &gregset->lcount);
  58         __put_user(regs->windowstart, &gregset->windowstart);
  59         __put_user(regs->windowbase, &gregset->windowbase);
  60
  61         live = (wm & 2) ? 4 : (wm & 4) ? 8 : (wm & 8) ? 12 : 16;
  62
  63         for (i = 0; i < live; i++)
  64                 __put_user(regs->areg[i],gregset->a+((wb*4+i)%XCHAL_NUM_AREGS));
  65         for (i = XCHAL_NUM_AREGS - (wm >> 4) * 4; i < XCHAL_NUM_AREGS; i++)
  66                 __put_user(regs->areg[i],gregset->a+((wb*4+i)%XCHAL_NUM_AREGS));
  67
  68         return 0;
  69 }
  70
  71 int ptrace_setregs(struct task_struct *child, void __user *uregs)
  72 {
  73         struct pt_regs *regs = task_pt_regs(child);
  74         xtensa_gregset_t *gregset = uregs;
  75         const unsigned long ps_mask = PS_CALLINC_MASK | PS_OWB_MASK;
  76         unsigned long ps;
  77         unsigned long wb;
  78
  79         if (!access_ok(VERIFY_WRITE, uregs, sizeof(xtensa_gregset_t)))
  80                 return -EIO;
  81
  82         __get_user(regs->pc, &gregset->pc);
  83         __get_user(ps, &gregset->ps);
  84         __get_user(regs->lbeg, &gregset->lbeg);
  85         __get_user(regs->lend, &gregset->lend);
  86         __get_user(regs->lcount, &gregset->lcount);
  87         __get_user(regs->windowstart, &gregset->windowstart);
  88         __get_user(wb, &gregset->windowbase);
  89
  90         regs->ps = (regs->ps & ~ps_mask) | (ps & ps_mask) | (1 << PS_EXCM_BIT);
  91
  92         if (wb >= XCHAL_NUM_AREGS / 4)
  93                 return -EFAULT;
  94
  95         regs->windowbase = wb;
  96
  97         if (wb != 0 &&  __copy_from_user(regs->areg + XCHAL_NUM_AREGS - wb * 4,
  98                                          gregset->a, wb * 16))
  99                 return -EFAULT;
 100
 101         if (__copy_from_user(regs->areg, gregset->a + wb*4, (WSBITS-wb) * 16))
 102                 return -EFAULT;
 103
 104         return 0;
 105 }
 106
 107
 108 int ptrace_getxregs(struct task_struct *child, void __user *uregs)
 109 {
 110         struct pt_regs *regs = task_pt_regs(child);
 111         struct thread_info *ti = task_thread_info(child);
 112         elf_xtregs_t __user *xtregs = uregs;
 113         int ret = 0;
 114
 115         if (!access_ok(VERIFY_WRITE, uregs, sizeof(elf_xtregs_t)))
 116                 return -EIO;
 117
 118 #if XTENSA_HAVE_COPROCESSORS
 119         /* Flush all coprocessor registers to memory. */
 120         coprocessor_flush_all(ti);
 121         ret |= __copy_to_user(&xtregs->cp0, &ti->xtregs_cp,
 122                               sizeof(xtregs_coprocessor_t));
 123 #endif
 124         ret |= __copy_to_user(&xtregs->opt, &regs->xtregs_opt,
 125                               sizeof(xtregs->opt));
 126         ret |= __copy_to_user(&xtregs->user,&ti->xtregs_user,
 127                               sizeof(xtregs->user));
 128
 129         return ret ? -EFAULT : 0;
 130 }
 131
 132 int ptrace_setxregs(struct task_struct *child, void __user *uregs)
 133 {
 134         struct thread_info *ti = task_thread_info(child);
 135         struct pt_regs *regs = task_pt_regs(child);
 136         elf_xtregs_t *xtregs = uregs;
 137         int ret = 0;
 138
 139         if (!access_ok(VERIFY_READ, uregs, sizeof(elf_xtregs_t)))
 140                 return -EFAULT;
 141
 142 #if XTENSA_HAVE_COPROCESSORS
 143         /* Flush all coprocessors before we overwrite them. */
 144         coprocessor_flush_all(ti);
 145         coprocessor_release_all(ti);
 146
 147         ret |= __copy_from_user(&ti->xtregs_cp, &xtregs->cp0,
 148                                 sizeof(xtregs_coprocessor_t));
 149 #endif
 150         ret |= __copy_from_user(&regs->xtregs_opt, &xtregs->opt,
 151                                 sizeof(xtregs->opt));
 152         ret |= __copy_from_user(&ti->xtregs_user, &xtregs->user,
 153                                 sizeof(xtregs->user));
 154
 155         return ret ? -EFAULT : 0;
 156 }
 157
 158 int ptrace_peekusr(struct task_struct *child, long regno, long __user *ret)
 159 {
 160         struct pt_regs *regs;
 161         unsigned long tmp;
 162
 163         regs = task_pt_regs(child);
 164         tmp = 0;  /* Default return value. */
 165
 166         switch(regno) {
 167
 168                 case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1:
 169                         tmp = regs->areg[regno - REG_AR_BASE];
 170                         break;
 171
 172                 case REG_A_BASE ... REG_A_BASE + 15:
 173                         tmp = regs->areg[regno - REG_A_BASE];
 174                         break;
 175
 176                 case REG_PC:
 177                         tmp = regs->pc;
 178                         break;
 179
 180                 case REG_PS:
 181                         /* Note:  PS.EXCM is not set while user task is running;
 182                          * its being set in regs is for exception handling
 183                          * convenience.  */
 184                         tmp = (regs->ps & ~(1 << PS_EXCM_BIT));
 185                         break;
 186
 187                 case REG_WB:
 188                         break;          /* tmp = 0 */
 189
 190                 case REG_WS:
 191                 {
 192                         unsigned long wb = regs->windowbase;
 193                         unsigned long ws = regs->windowstart;
 194                         tmp = ((ws>>wb) | (ws<<(WSBITS-wb))) & ((1<<WSBITS)-1);
 195                         break;
 196                 }
 197                 case REG_LBEG:
 198                         tmp = regs->lbeg;
 199                         break;
 200
 201                 case REG_LEND:
 202                         tmp = regs->lend;
 203                         break;
 204
 205                 case REG_LCOUNT:
 206                         tmp = regs->lcount;
 207                         break;
 208
 209                 case REG_SAR:
 210                         tmp = regs->sar;
 211                         break;
 212
 213                 case SYSCALL_NR:
 214                         tmp = regs->syscall;
 215                         break;
 216
 217                 default:
 218                         return -EIO;
 219         }
 220         return put_user(tmp, ret);
 221 }
 222
 223 int ptrace_pokeusr(struct task_struct *child, long regno, long val)
 224 {
 225         struct pt_regs *regs;
 226         regs = task_pt_regs(child);
 227
 228         switch (regno) {
 229                 case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1:
 230                         regs->areg[regno - REG_AR_BASE] = val;
 231                         break;
 232
 233                 case REG_A_BASE ... REG_A_BASE + 15:
 234                         regs->areg[regno - REG_A_BASE] = val;
 235                         break;
 236
 237                 case REG_PC:
 238                         regs->pc = val;
 239                         break;
 240
 241                 case SYSCALL_NR:
 242                         regs->syscall = val;
 243                         break;
 244
 245                 default:
 246                         return -EIO;
 247         }
 248         return 0;
 249 }
 250
 251 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 252 {
 253         int ret = -EPERM;
 254
 255         switch (request) {
 256         case PTRACE_PEEKTEXT:   /* read word at location addr. */
 257         case PTRACE_PEEKDATA:
 258                 ret = generic_ptrace_peekdata(child, addr, data);
 259                 break;
 260
 261         case PTRACE_PEEKUSR:    /* read register specified by addr. */
 262                 ret = ptrace_peekusr(child, addr, (void __user *) data);
 263                 break;
 264
 265         case PTRACE_POKETEXT:   /* write the word at location addr. */
 266         case PTRACE_POKEDATA:
 267                 ret = generic_ptrace_pokedata(child, addr, data);
 268                 break;
 269
 270         case PTRACE_POKEUSR:    /* write register specified by addr. */
 271                 ret = ptrace_pokeusr(child, addr, data);
 272                 break;
 273
 274         /* continue and stop at next (return from) syscall */
 275
 276         case PTRACE_SYSCALL:
 277         case PTRACE_CONT: /* restart after signal. */
 278         {
 279                 ret = -EIO;
 280                 if (!valid_signal(data))
 281                         break;
 282                 if (request == PTRACE_SYSCALL)
 283                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 284                 else
 285                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 286                 child->exit_code = data;
 287                 /* Make sure the single step bit is not set. */
 288                 child->ptrace &= ~PT_SINGLESTEP;
 289                 wake_up_process(child);
 290                 ret = 0;
 291                 break;
 292         }
 293
 294         /*
 295          * make the child exit.  Best I can do is send it a sigkill.
 296          * perhaps it should be put in the status that it wants to
 297          * exit.
 298          */
 299         case PTRACE_KILL:
 300                 ret = 0;
 301                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 302                         break;
 303                 child->exit_code = SIGKILL;
 304                 child->ptrace &= ~PT_SINGLESTEP;
 305                 wake_up_process(child);
 306                 break;
 307
 308         case PTRACE_SINGLESTEP:
 309                 ret = -EIO;
 310                 if (!valid_signal(data))
 311                         break;
 312                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 313                 child->ptrace |= PT_SINGLESTEP;
 314                 child->exit_code = data;
 315                 wake_up_process(child);
 316                 ret = 0;
 317                 break;
 318
 319         case PTRACE_GETREGS:
 320                 ret = ptrace_getregs(child, (void __user *) data);
 321                 break;
 322
 323         case PTRACE_SETREGS:
 324                 ret = ptrace_setregs(child, (void __user *) data);
 325                 break;
 326
 327         case PTRACE_GETXTREGS:
 328                 ret = ptrace_getxregs(child, (void __user *) data);
 329                 break;
 330
 331         case PTRACE_SETXTREGS:
 332                 ret = ptrace_setxregs(child, (void __user *) data);
 333                 break;
 334
 335         default:
 336                 ret = ptrace_request(child, request, addr, data);
 337                 break;
 338         }
 339
 340         return ret;
 341 }
 342
 343 void do_syscall_trace(void)
 344 {
 345         /*
 346          * The 0x80 provides a way for the tracing parent to distinguish
 347          * between a syscall stop and SIGTRAP delivery
 348          */
 349         ptrace_notify(SIGTRAP|((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));
 350
 351         /*
 352          * this isn't the same as continuing with a signal, but it will do
 353          * for normal use.  strace only continues with a signal if the
 354          * stopping signal is not SIGTRAP.  -brl
 355          */
 356         if (current->exit_code) {
 357                 send_sig(current->exit_code, current, 1);
 358                 current->exit_code = 0;
 359         }
 360 }
 361
 362 void do_syscall_trace_enter(struct pt_regs *regs)
 363 {
 364         if (test_thread_flag(TIF_SYSCALL_TRACE)
 365                         && (current->ptrace & PT_PTRACED))
 366                 do_syscall_trace();
 367
 368 #if 0
 369         if (unlikely(current->audit_context))
 370                 audit_syscall_entry(current, AUDIT_ARCH_XTENSA..);
 371 #endif
 372 }
 373
 374 void do_syscall_trace_leave(struct pt_regs *regs)
 375 {
 376         if ((test_thread_flag(TIF_SYSCALL_TRACE))
 377                         && (current->ptrace & PT_PTRACED))
 378                 do_syscall_trace();
 379 }
 380