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/uaccess.h>
  28 #include <asm/ptrace.h>
  29 #include <asm/elf.h>
  30 #include <asm/coprocessor.h>
  31
  32
  33 void user_enable_single_step(struct task_struct *child)
  34 {
  35         child->ptrace |= PT_SINGLESTEP;
  36 }
  37
  38 void user_disable_single_step(struct task_struct *child)
  39 {
  40         child->ptrace &= ~PT_SINGLESTEP;
  41 }
  42
  43 /*
  44  * Called by kernel/ptrace.c when detaching to disable single stepping.
  45  */
  46
  47 void ptrace_disable(struct task_struct *child)
  48 {
  49         /* Nothing to do.. */
  50 }
  51
  52 int ptrace_getregs(struct task_struct *child, void __user *uregs)
  53 {
  54         struct pt_regs *regs = task_pt_regs(child);
  55         xtensa_gregset_t __user *gregset = uregs;
  56         unsigned long wb = regs->windowbase;
  57         int i;
  58
  59         if (!access_ok(VERIFY_WRITE, uregs, sizeof(xtensa_gregset_t)))
  60                 return -EIO;
  61
  62         __put_user(regs->pc, &gregset->pc);
  63         __put_user(regs->ps & ~(1 << PS_EXCM_BIT), &gregset->ps);
  64         __put_user(regs->lbeg, &gregset->lbeg);
  65         __put_user(regs->lend, &gregset->lend);
  66         __put_user(regs->lcount, &gregset->lcount);
  67         __put_user(regs->windowstart, &gregset->windowstart);
  68         __put_user(regs->windowbase, &gregset->windowbase);
  69         __put_user(regs->threadptr, &gregset->threadptr);
  70
  71         for (i = 0; i < XCHAL_NUM_AREGS; i++)
  72                 __put_user(regs->areg[i],
  73                                 gregset->a + ((wb * 4 + i) % XCHAL_NUM_AREGS));
  74
  75         return 0;
  76 }
  77
  78 int ptrace_setregs(struct task_struct *child, void __user *uregs)
  79 {
  80         struct pt_regs *regs = task_pt_regs(child);
  81         xtensa_gregset_t *gregset = uregs;
  82         const unsigned long ps_mask = PS_CALLINC_MASK | PS_OWB_MASK;
  83         unsigned long ps;
  84         unsigned long wb, ws;
  85
  86         if (!access_ok(VERIFY_WRITE, uregs, sizeof(xtensa_gregset_t)))
  87                 return -EIO;
  88
  89         __get_user(regs->pc, &gregset->pc);
  90         __get_user(ps, &gregset->ps);
  91         __get_user(regs->lbeg, &gregset->lbeg);
  92         __get_user(regs->lend, &gregset->lend);
  93         __get_user(regs->lcount, &gregset->lcount);
  94         __get_user(ws, &gregset->windowstart);
  95         __get_user(wb, &gregset->windowbase);
  96         __get_user(regs->threadptr, &gregset->threadptr);
  97
  98         regs->ps = (regs->ps & ~ps_mask) | (ps & ps_mask) | (1 << PS_EXCM_BIT);
  99
 100         if (wb >= XCHAL_NUM_AREGS / 4)
 101                 return -EFAULT;
 102
 103         if (wb != regs->windowbase || ws != regs->windowstart) {
 104                 unsigned long rotws, wmask;
 105
 106                 rotws = (((ws | (ws << WSBITS)) >> wb) &
 107                                 ((1 << WSBITS) - 1)) & ~1;
 108                 wmask = ((rotws ? WSBITS + 1 - ffs(rotws) : 0) << 4) |
 109                         (rotws & 0xF) | 1;
 110                 regs->windowbase = wb;
 111                 regs->windowstart = ws;
 112                 regs->wmask = wmask;
 113         }
 114
 115         if (wb != 0 &&  __copy_from_user(regs->areg + XCHAL_NUM_AREGS - wb * 4,
 116                                 gregset->a, wb * 16))
 117                 return -EFAULT;
 118
 119         if (__copy_from_user(regs->areg, gregset->a + wb * 4,
 120                                 (WSBITS - wb) * 16))
 121                 return -EFAULT;
 122
 123         return 0;
 124 }
 125
 126
 127 int ptrace_getxregs(struct task_struct *child, void __user *uregs)
 128 {
 129         struct pt_regs *regs = task_pt_regs(child);
 130         struct thread_info *ti = task_thread_info(child);
 131         elf_xtregs_t __user *xtregs = uregs;
 132         int ret = 0;
 133
 134         if (!access_ok(VERIFY_WRITE, uregs, sizeof(elf_xtregs_t)))
 135                 return -EIO;
 136
 137 #if XTENSA_HAVE_COPROCESSORS
 138         /* Flush all coprocessor registers to memory. */
 139         coprocessor_flush_all(ti);
 140         ret |= __copy_to_user(&xtregs->cp0, &ti->xtregs_cp,
 141                               sizeof(xtregs_coprocessor_t));
 142 #endif
 143         ret |= __copy_to_user(&xtregs->opt, &regs->xtregs_opt,
 144                               sizeof(xtregs->opt));
 145         ret |= __copy_to_user(&xtregs->user,&ti->xtregs_user,
 146                               sizeof(xtregs->user));
 147
 148         return ret ? -EFAULT : 0;
 149 }
 150
 151 int ptrace_setxregs(struct task_struct *child, void __user *uregs)
 152 {
 153         struct thread_info *ti = task_thread_info(child);
 154         struct pt_regs *regs = task_pt_regs(child);
 155         elf_xtregs_t *xtregs = uregs;
 156         int ret = 0;
 157
 158         if (!access_ok(VERIFY_READ, uregs, sizeof(elf_xtregs_t)))
 159                 return -EFAULT;
 160
 161 #if XTENSA_HAVE_COPROCESSORS
 162         /* Flush all coprocessors before we overwrite them. */
 163         coprocessor_flush_all(ti);
 164         coprocessor_release_all(ti);
 165
 166         ret |= __copy_from_user(&ti->xtregs_cp, &xtregs->cp0,
 167                                 sizeof(xtregs_coprocessor_t));
 168 #endif
 169         ret |= __copy_from_user(&regs->xtregs_opt, &xtregs->opt,
 170                                 sizeof(xtregs->opt));
 171         ret |= __copy_from_user(&ti->xtregs_user, &xtregs->user,
 172                                 sizeof(xtregs->user));
 173
 174         return ret ? -EFAULT : 0;
 175 }
 176
 177 int ptrace_peekusr(struct task_struct *child, long regno, long __user *ret)
 178 {
 179         struct pt_regs *regs;
 180         unsigned long tmp;
 181
 182         regs = task_pt_regs(child);
 183         tmp = 0;  /* Default return value. */
 184
 185         switch(regno) {
 186
 187                 case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1:
 188                         tmp = regs->areg[regno - REG_AR_BASE];
 189                         break;
 190
 191                 case REG_A_BASE ... REG_A_BASE + 15:
 192                         tmp = regs->areg[regno - REG_A_BASE];
 193                         break;
 194
 195                 case REG_PC:
 196                         tmp = regs->pc;
 197                         break;
 198
 199                 case REG_PS:
 200                         /* Note:  PS.EXCM is not set while user task is running;
 201                          * its being set in regs is for exception handling
 202                          * convenience.  */
 203                         tmp = (regs->ps & ~(1 << PS_EXCM_BIT));
 204                         break;
 205
 206                 case REG_WB:
 207                         break;          /* tmp = 0 */
 208
 209                 case REG_WS:
 210                 {
 211                         unsigned long wb = regs->windowbase;
 212                         unsigned long ws = regs->windowstart;
 213                         tmp = ((ws>>wb) | (ws<<(WSBITS-wb))) & ((1<<WSBITS)-1);
 214                         break;
 215                 }
 216                 case REG_LBEG:
 217                         tmp = regs->lbeg;
 218                         break;
 219
 220                 case REG_LEND:
 221                         tmp = regs->lend;
 222                         break;
 223
 224                 case REG_LCOUNT:
 225                         tmp = regs->lcount;
 226                         break;
 227
 228                 case REG_SAR:
 229                         tmp = regs->sar;
 230                         break;
 231
 232                 case SYSCALL_NR:
 233                         tmp = regs->syscall;
 234                         break;
 235
 236                 default:
 237                         return -EIO;
 238         }
 239         return put_user(tmp, ret);
 240 }
 241
 242 int ptrace_pokeusr(struct task_struct *child, long regno, long val)
 243 {
 244         struct pt_regs *regs;
 245         regs = task_pt_regs(child);
 246
 247         switch (regno) {
 248                 case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1:
 249                         regs->areg[regno - REG_AR_BASE] = val;
 250                         break;
 251
 252                 case REG_A_BASE ... REG_A_BASE + 15:
 253                         regs->areg[regno - REG_A_BASE] = val;
 254                         break;
 255
 256                 case REG_PC:
 257                         regs->pc = val;
 258                         break;
 259
 260                 case SYSCALL_NR:
 261                         regs->syscall = val;
 262                         break;
 263
 264                 default:
 265                         return -EIO;
 266         }
 267         return 0;
 268 }
 269
 270 long arch_ptrace(struct task_struct *child, long request,
 271                  unsigned long addr, unsigned long data)
 272 {
 273         int ret = -EPERM;
 274         void __user *datap = (void __user *) data;
 275
 276         switch (request) {
 277         case PTRACE_PEEKTEXT:   /* read word at location addr. */
 278         case PTRACE_PEEKDATA:
 279                 ret = generic_ptrace_peekdata(child, addr, data);
 280                 break;
 281
 282         case PTRACE_PEEKUSR:    /* read register specified by addr. */
 283                 ret = ptrace_peekusr(child, addr, datap);
 284                 break;
 285
 286         case PTRACE_POKETEXT:   /* write the word at location addr. */
 287         case PTRACE_POKEDATA:
 288                 ret = generic_ptrace_pokedata(child, addr, data);
 289                 break;
 290
 291         case PTRACE_POKEUSR:    /* write register specified by addr. */
 292                 ret = ptrace_pokeusr(child, addr, data);
 293                 break;
 294
 295         case PTRACE_GETREGS:
 296                 ret = ptrace_getregs(child, datap);
 297                 break;
 298
 299         case PTRACE_SETREGS:
 300                 ret = ptrace_setregs(child, datap);
 301                 break;
 302
 303         case PTRACE_GETXTREGS:
 304                 ret = ptrace_getxregs(child, datap);
 305                 break;
 306
 307         case PTRACE_SETXTREGS:
 308                 ret = ptrace_setxregs(child, datap);
 309                 break;
 310
 311         default:
 312                 ret = ptrace_request(child, request, addr, data);
 313                 break;
 314         }
 315
 316         return ret;
 317 }
 318
 319 void do_syscall_trace(void)
 320 {
 321         /*
 322          * The 0x80 provides a way for the tracing parent to distinguish
 323          * between a syscall stop and SIGTRAP delivery
 324          */
 325         ptrace_notify(SIGTRAP|((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));
 326
 327         /*
 328          * this isn't the same as continuing with a signal, but it will do
 329          * for normal use.  strace only continues with a signal if the
 330          * stopping signal is not SIGTRAP.  -brl
 331          */
 332         if (current->exit_code) {
 333                 send_sig(current->exit_code, current, 1);
 334                 current->exit_code = 0;
 335         }
 336 }
 337
 338 void do_syscall_trace_enter(struct pt_regs *regs)
 339 {
 340         if (test_thread_flag(TIF_SYSCALL_TRACE)
 341                         && (current->ptrace & PT_PTRACED))
 342                 do_syscall_trace();
 343
 344 #if 0
 345         audit_syscall_entry(...);
 346 #endif
 347 }
 348
 349 void do_syscall_trace_leave(struct pt_regs *regs)
 350 {
 351         if ((test_thread_flag(TIF_SYSCALL_TRACE))
 352                         && (current->ptrace & PT_PTRACED))
 353                 do_syscall_trace();
 354 }