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