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