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 XTENSA_HAVE_COPROCESSORS
 140         /* Flush all coprocessors before we overwrite them. */
 141         coprocessor_flush_all(ti);
 142         coprocessor_release_all(ti);
 143
 144         ret |= __copy_from_user(&ti->xtregs_cp, &xtregs->cp0,
 145                                 sizeof(xtregs_coprocessor_t));
 146 #endif
 147         ret |= __copy_from_user(&regs->xtregs_opt, &xtregs->opt,
 148                                 sizeof(xtregs->opt));
 149         ret |= __copy_from_user(&ti->xtregs_user, &xtregs->user,
 150                                 sizeof(xtregs->user));
 151
 152         return ret ? -EFAULT : 0;
 153 }
 154
 155 int ptrace_peekusr(struct task_struct *child, long regno, long __user *ret)
 156 {
 157         struct pt_regs *regs;
 158         unsigned long tmp;
 159
 160         regs = task_pt_regs(child);
 161         tmp = 0;  /* Default return value. */
 162
 163         switch(regno) {
 164
 165                 case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1:
 166                         tmp = regs->areg[regno - REG_AR_BASE];
 167                         break;
 168
 169                 case REG_A_BASE ... REG_A_BASE + 15:
 170                         tmp = regs->areg[regno - REG_A_BASE];
 171                         break;
 172
 173                 case REG_PC:
 174                         tmp = regs->pc;
 175                         break;
 176
 177                 case REG_PS:
 178                         /* Note:  PS.EXCM is not set while user task is running;
 179                          * its being set in regs is for exception handling
 180                          * convenience.  */
 181                         tmp = (regs->ps & ~(1 << PS_EXCM_BIT));
 182                         break;
 183
 184                 case REG_WB:
 185                         break;          /* tmp = 0 */
 186
 187                 case REG_WS:
 188                 {
 189                         unsigned long wb = regs->windowbase;
 190                         unsigned long ws = regs->windowstart;
 191                         tmp = ((ws>>wb) | (ws<<(WSBITS-wb))) & ((1<<WSBITS)-1);
 192                         break;
 193                 }
 194                 case REG_LBEG:
 195                         tmp = regs->lbeg;
 196                         break;
 197
 198                 case REG_LEND:
 199                         tmp = regs->lend;
 200                         break;
 201
 202                 case REG_LCOUNT:
 203                         tmp = regs->lcount;
 204                         break;
 205
 206                 case REG_SAR:
 207                         tmp = regs->sar;
 208                         break;
 209
 210                 case SYSCALL_NR:
 211                         tmp = regs->syscall;
 212                         break;
 213
 214                 default:
 215                         return -EIO;
 216         }
 217         return put_user(tmp, ret);
 218 }
 219
 220 int ptrace_pokeusr(struct task_struct *child, long regno, long val)
 221 {
 222         struct pt_regs *regs;
 223         regs = task_pt_regs(child);
 224
 225         switch (regno) {
 226                 case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1:
 227                         regs->areg[regno - REG_AR_BASE] = val;
 228                         break;
 229
 230                 case REG_A_BASE ... REG_A_BASE + 15:
 231                         regs->areg[regno - REG_A_BASE] = val;
 232                         break;
 233
 234                 case REG_PC:
 235                         regs->pc = val;
 236                         break;
 237
 238                 case SYSCALL_NR:
 239                         regs->syscall = val;
 240                         break;
 241
 242                 default:
 243                         return -EIO;
 244         }
 245         return 0;
 246 }
 247
 248 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 249 {
 250         int ret = -EPERM;
 251
 252         switch (request) {
 253         case PTRACE_PEEKTEXT:   /* read word at location addr. */
 254         case PTRACE_PEEKDATA:
 255                 ret = generic_ptrace_peekdata(child, addr, data);
 256                 break;
 257
 258         case PTRACE_PEEKUSR:    /* read register specified by addr. */
 259                 ret = ptrace_peekusr(child, addr, (void __user *) data);
 260                 break;
 261
 262         case PTRACE_POKETEXT:   /* write the word at location addr. */
 263         case PTRACE_POKEDATA:
 264                 ret = generic_ptrace_pokedata(child, addr, data);
 265                 break;
 266
 267         case PTRACE_POKEUSR:    /* write register specified by addr. */
 268                 ret = ptrace_pokeusr(child, addr, data);
 269                 break;
 270
 271         /* continue and stop at next (return from) syscall */
 272
 273         case PTRACE_SYSCALL:
 274         case PTRACE_CONT: /* restart after signal. */
 275         {
 276                 ret = -EIO;
 277                 if (!valid_signal(data))
 278                         break;
 279                 if (request == PTRACE_SYSCALL)
 280                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 281                 else
 282                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 283                 child->exit_code = data;
 284                 /* Make sure the single step bit is not set. */
 285                 child->ptrace &= ~PT_SINGLESTEP;
 286                 wake_up_process(child);
 287                 ret = 0;
 288                 break;
 289         }
 290
 291         /*
 292          * make the child exit.  Best I can do is send it a sigkill.
 293          * perhaps it should be put in the status that it wants to
 294          * exit.
 295          */
 296         case PTRACE_KILL:
 297                 ret = 0;
 298                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 299                         break;
 300                 child->exit_code = SIGKILL;
 301                 child->ptrace &= ~PT_SINGLESTEP;
 302                 wake_up_process(child);
 303                 break;
 304
 305         case PTRACE_SINGLESTEP:
 306                 ret = -EIO;
 307                 if (!valid_signal(data))
 308                         break;
 309                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 310                 child->ptrace |= PT_SINGLESTEP;
 311                 child->exit_code = data;
 312                 wake_up_process(child);
 313                 ret = 0;
 314                 break;
 315
 316         case PTRACE_GETREGS:
 317                 ret = ptrace_getregs(child, (void __user *) data);
 318                 break;
 319
 320         case PTRACE_SETREGS:
 321                 ret = ptrace_setregs(child, (void __user *) data);
 322                 break;
 323
 324         case PTRACE_GETXTREGS:
 325                 ret = ptrace_getxregs(child, (void __user *) data);
 326                 break;
 327
 328         case PTRACE_SETXTREGS:
 329                 ret = ptrace_setxregs(child, (void __user *) data);
 330                 break;
 331
 332         default:
 333                 ret = ptrace_request(child, request, addr, data);
 334                 break;
 335         }
 336
 337         return ret;
 338 }
 339
 340 void do_syscall_trace(void)
 341 {
 342         /*
 343          * The 0x80 provides a way for the tracing parent to distinguish
 344          * between a syscall stop and SIGTRAP delivery
 345          */
 346         ptrace_notify(SIGTRAP|((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));
 347
 348         /*
 349          * this isn't the same as continuing with a signal, but it will do
 350          * for normal use.  strace only continues with a signal if the
 351          * stopping signal is not SIGTRAP.  -brl
 352          */
 353         if (current->exit_code) {
 354                 send_sig(current->exit_code, current, 1);
 355                 current->exit_code = 0;
 356         }
 357 }
 358
 359 void do_syscall_trace_enter(struct pt_regs *regs)
 360 {
 361         if (test_thread_flag(TIF_SYSCALL_TRACE)
 362                         && (current->ptrace & PT_PTRACED))
 363                 do_syscall_trace();
 364
 365 #if 0
 366         if (unlikely(current->audit_context))
 367                 audit_syscall_entry(current, AUDIT_ARCH_XTENSA..);
 368 #endif
 369 }
 370
 371 void do_syscall_trace_leave(struct pt_regs *regs)
 372 {
 373         if ((test_thread_flag(TIF_SYSCALL_TRACE))
 374                         && (current->ptrace & PT_PTRACED))
 375                 do_syscall_trace();
 376 }
 377