arch/sh64/kernel/ptrace.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * arch/sh64/kernel/ptrace.c
   7  *
   8  * Copyright (C) 2000, 2001  Paolo Alberelli
   9  * Copyright (C) 2003  Paul Mundt
  10  *
  11  * Started from SH3/4 version:
  12  *   SuperH version:   Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
  13  *
  14  *   Original x86 implementation:
  15  *      By Ross Biro 1/23/92
  16  *      edited by Linus Torvalds
  17  *
  18  */
  19
  20 #include <linux/config.h>
  21 #include <linux/kernel.h>
  22 #include <linux/rwsem.h>
  23 #include <linux/sched.h>
  24 #include <linux/mm.h>
  25 #include <linux/smp.h>
  26 #include <linux/smp_lock.h>
  27 #include <linux/errno.h>
  28 #include <linux/ptrace.h>
  29 #include <linux/user.h>
  30 #include <linux/signal.h>
  31 #include <linux/syscalls.h>
  32
  33 #include <asm/io.h>
  34 #include <asm/uaccess.h>
  35 #include <asm/pgtable.h>
  36 #include <asm/system.h>
  37 #include <asm/processor.h>
  38 #include <asm/mmu_context.h>
  39
  40 /* This mask defines the bits of the SR which the user is not allowed to
  41    change, which are everything except S, Q, M, PR, SZ, FR. */
  42 #define SR_MASK      (0xffff8cfd)
  43
  44 /*
  45  * does not yet catch signals sent when the child dies.
  46  * in exit.c or in signal.c.
  47  */
  48
  49 /*
  50  * This routine will get a word from the user area in the process kernel stack.
  51  */
  52 static inline int get_stack_long(struct task_struct *task, int offset)
  53 {
  54         unsigned char *stack;
  55
  56         stack = (unsigned char *)(task->thread.uregs);
  57         stack += offset;
  58         return (*((int *)stack));
  59 }
  60
  61 static inline unsigned long
  62 get_fpu_long(struct task_struct *task, unsigned long addr)
  63 {
  64         unsigned long tmp;
  65         struct pt_regs *regs;
  66         regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;
  67
  68         if (!tsk_used_math(task)) {
  69                 if (addr == offsetof(struct user_fpu_struct, fpscr)) {
  70                         tmp = FPSCR_INIT;
  71                 } else {
  72                         tmp = 0xffffffffUL; /* matches initial value in fpu.c */
  73                 }
  74                 return tmp;
  75         }
  76
  77         if (last_task_used_math == task) {
  78                 grab_fpu();
  79                 fpsave(&task->thread.fpu.hard);
  80                 release_fpu();
  81                 last_task_used_math = 0;
  82                 regs->sr |= SR_FD;
  83         }
  84
  85         tmp = ((long *)&task->thread.fpu)[addr / sizeof(unsigned long)];
  86         return tmp;
  87 }
  88
  89 /*
  90  * This routine will put a word into the user area in the process kernel stack.
  91  */
  92 static inline int put_stack_long(struct task_struct *task, int offset,
  93                                  unsigned long data)
  94 {
  95         unsigned char *stack;
  96
  97         stack = (unsigned char *)(task->thread.uregs);
  98         stack += offset;
  99         *(unsigned long *) stack = data;
 100         return 0;
 101 }
 102
 103 static inline int
 104 put_fpu_long(struct task_struct *task, unsigned long addr, unsigned long data)
 105 {
 106         struct pt_regs *regs;
 107
 108         regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;
 109
 110         if (!tsk_used_math(task)) {
 111                 fpinit(&task->thread.fpu.hard);
 112                 set_stopped_child_used_math(task);
 113         } else if (last_task_used_math == task) {
 114                 grab_fpu();
 115                 fpsave(&task->thread.fpu.hard);
 116                 release_fpu();
 117                 last_task_used_math = 0;
 118                 regs->sr |= SR_FD;
 119         }
 120
 121         ((long *)&task->thread.fpu)[addr / sizeof(unsigned long)] = data;
 122         return 0;
 123 }
 124
 125
 126 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 127 {
 128         int ret;
 129
 130         switch (request) {
 131         /* when I and D space are separate, these will need to be fixed. */
 132         case PTRACE_PEEKTEXT: /* read word at location addr. */
 133         case PTRACE_PEEKDATA: {
 134                 unsigned long tmp;
 135                 int copied;
 136
 137                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 138                 ret = -EIO;
 139                 if (copied != sizeof(tmp))
 140                         break;
 141                 ret = put_user(tmp,(unsigned long *) data);
 142                 break;
 143         }
 144
 145         /* read the word at location addr in the USER area. */
 146         case PTRACE_PEEKUSR: {
 147                 unsigned long tmp;
 148
 149                 ret = -EIO;
 150                 if ((addr & 3) || addr < 0)
 151                         break;
 152
 153                 if (addr < sizeof(struct pt_regs))
 154                         tmp = get_stack_long(child, addr);
 155                 else if ((addr >= offsetof(struct user, fpu)) &&
 156                          (addr <  offsetof(struct user, u_fpvalid))) {
 157                         tmp = get_fpu_long(child, addr - offsetof(struct user, fpu));
 158                 } else if (addr == offsetof(struct user, u_fpvalid)) {
 159                         tmp = !!tsk_used_math(child);
 160                 } else {
 161                         break;
 162                 }
 163                 ret = put_user(tmp, (unsigned long *)data);
 164                 break;
 165         }
 166
 167         /* when I and D space are separate, this will have to be fixed. */
 168         case PTRACE_POKETEXT: /* write the word at location addr. */
 169         case PTRACE_POKEDATA:
 170                 ret = 0;
 171                 if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
 172                         break;
 173                 ret = -EIO;
 174                 break;
 175
 176         case PTRACE_POKEUSR:
 177                 /* write the word at location addr in the USER area. We must
 178                    disallow any changes to certain SR bits or u_fpvalid, since
 179                    this could crash the kernel or result in a security
 180                    loophole. */
 181                 ret = -EIO;
 182                 if ((addr & 3) || addr < 0)
 183                         break;
 184
 185                 if (addr < sizeof(struct pt_regs)) {
 186                         /* Ignore change of top 32 bits of SR */
 187                         if (addr == offsetof (struct pt_regs, sr)+4)
 188                         {
 189                                 ret = 0;
 190                                 break;
 191                         }
 192                         /* If lower 32 bits of SR, ignore non-user bits */
 193                         if (addr == offsetof (struct pt_regs, sr))
 194                         {
 195                                 long cursr = get_stack_long(child, addr);
 196                                 data &= ~(SR_MASK);
 197                                 data |= (cursr & SR_MASK);
 198                         }
 199                         ret = put_stack_long(child, addr, data);
 200                 }
 201                 else if ((addr >= offsetof(struct user, fpu)) &&
 202                          (addr <  offsetof(struct user, u_fpvalid))) {
 203                         ret = put_fpu_long(child, addr - offsetof(struct user, fpu), data);
 204                 }
 205                 break;
 206
 207         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 208         case PTRACE_CONT: { /* restart after signal. */
 209                 ret = -EIO;
 210                 if (!valid_signal(data))
 211                         break;
 212                 if (request == PTRACE_SYSCALL)
 213                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 214                 else
 215                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 216                 child->exit_code = data;
 217                 wake_up_process(child);
 218                 ret = 0;
 219                 break;
 220         }
 221
 222 /*
 223  * make the child exit.  Best I can do is send it a sigkill.
 224  * perhaps it should be put in the status that it wants to
 225  * exit.
 226  */
 227         case PTRACE_KILL: {
 228                 ret = 0;
 229                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 230                         break;
 231                 child->exit_code = SIGKILL;
 232                 wake_up_process(child);
 233                 break;
 234         }
 235
 236         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 237                 struct pt_regs *regs;
 238
 239                 ret = -EIO;
 240                 if (!valid_signal(data))
 241                         break;
 242                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 243                 if ((child->ptrace & PT_DTRACE) == 0) {
 244                         /* Spurious delayed TF traps may occur */
 245                         child->ptrace |= PT_DTRACE;
 246                 }
 247
 248                 regs = child->thread.uregs;
 249
 250                 regs->sr |= SR_SSTEP;   /* auto-resetting upon exception */
 251
 252                 child->exit_code = data;
 253                 /* give it a chance to run. */
 254                 wake_up_process(child);
 255                 ret = 0;
 256                 break;
 257         }
 258
 259         case PTRACE_DETACH: /* detach a process that was attached. */
 260                 ret = ptrace_detach(child, data);
 261                 break;
 262
 263         default:
 264                 ret = ptrace_request(child, request, addr, data);
 265                 break;
 266         }
 267         return ret;
 268 }
 269
 270 asmlinkage int sh64_ptrace(long request, long pid, long addr, long data)
 271 {
 272         extern void poke_real_address_q(unsigned long long addr, unsigned long long data);
 273 #define WPC_DBRMODE 0x0d104008
 274         static int first_call = 1;
 275
 276         lock_kernel();
 277         if (first_call) {
 278                 /* Set WPC.DBRMODE to 0.  This makes all debug events get
 279                  * delivered through RESVEC, i.e. into the handlers in entry.S.
 280                  * (If the kernel was downloaded using a remote gdb, WPC.DBRMODE
 281                  * would normally be left set to 1, which makes debug events get
 282                  * delivered through DBRVEC, i.e. into the remote gdb's
 283                  * handlers.  This prevents ptrace getting them, and confuses
 284                  * the remote gdb.) */
 285                 printk("DBRMODE set to 0 to permit native debugging\n");
 286                 poke_real_address_q(WPC_DBRMODE, 0);
 287                 first_call = 0;
 288         }
 289         unlock_kernel();
 290
 291         return sys_ptrace(request, pid, addr, data);
 292 }
 293
 294 asmlinkage void syscall_trace(void)
 295 {
 296         struct task_struct *tsk = current;
 297
 298         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 299                 return;
 300         if (!(tsk->ptrace & PT_PTRACED))
 301                 return;
 302
 303         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 304                                  ? 0x80 : 0));
 305         /*
 306          * this isn't the same as continuing with a signal, but it will do
 307          * for normal use.  strace only continues with a signal if the
 308          * stopping signal is not SIGTRAP.  -brl
 309          */
 310         if (tsk->exit_code) {
 311                 send_sig(tsk->exit_code, tsk, 1);
 312                 tsk->exit_code = 0;
 313         }
 314 }
 315
 316 /* Called with interrupts disabled */
 317 asmlinkage void do_single_step(unsigned long long vec, struct pt_regs *regs)
 318 {
 319         /* This is called after a single step exception (DEBUGSS).
 320            There is no need to change the PC, as it is a post-execution
 321            exception, as entry.S does not do anything to the PC for DEBUGSS.
 322            We need to clear the Single Step setting in SR to avoid
 323            continually stepping. */
 324         local_irq_enable();
 325         regs->sr &= ~SR_SSTEP;
 326         force_sig(SIGTRAP, current);
 327 }
 328
 329 /* Called with interrupts disabled */
 330 asmlinkage void do_software_break_point(unsigned long long vec,
 331                                         struct pt_regs *regs)
 332 {
 333         /* We need to forward step the PC, to counteract the backstep done
 334            in signal.c. */
 335         local_irq_enable();
 336         force_sig(SIGTRAP, current);
 337         regs->pc += 4;
 338 }
 339
 340 /*
 341  * Called by kernel/ptrace.c when detaching..
 342  *
 343  * Make sure single step bits etc are not set.
 344  */
 345 void ptrace_disable(struct task_struct *child)
 346 {
 347         /* nothing to do.. */
 348 }