arch/sh/kernel/ptrace_32.c

   1 /*
   2  * linux/arch/sh/kernel/ptrace.c
   3  *
   4  * Original x86 implementation:
   5  *      By Ross Biro 1/23/92
   6  *      edited by Linus Torvalds
   7  *
   8  * SuperH version:   Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
   9  * Audit support: Yuichi Nakamura <ynakam@hitachisoft.jp>
  10  */
  11 #include <linux/kernel.h>
  12 #include <linux/sched.h>
  13 #include <linux/mm.h>
  14 #include <linux/smp.h>
  15 #include <linux/errno.h>
  16 #include <linux/ptrace.h>
  17 #include <linux/user.h>
  18 #include <linux/slab.h>
  19 #include <linux/security.h>
  20 #include <linux/signal.h>
  21 #include <linux/io.h>
  22 #include <linux/audit.h>
  23 #include <asm/uaccess.h>
  24 #include <asm/pgtable.h>
  25 #include <asm/system.h>
  26 #include <asm/processor.h>
  27 #include <asm/mmu_context.h>
  28
  29 /*
  30  * does not yet catch signals sent when the child dies.
  31  * in exit.c or in signal.c.
  32  */
  33
  34 /*
  35  * This routine will get a word off of the process kernel stack.
  36  */
  37 static inline int get_stack_long(struct task_struct *task, int offset)
  38 {
  39         unsigned char *stack;
  40
  41         stack = (unsigned char *)task_pt_regs(task);
  42         stack += offset;
  43         return (*((int *)stack));
  44 }
  45
  46 /*
  47  * This routine will put a word on the process kernel stack.
  48  */
  49 static inline int put_stack_long(struct task_struct *task, int offset,
  50                                  unsigned long data)
  51 {
  52         unsigned char *stack;
  53
  54         stack = (unsigned char *)task_pt_regs(task);
  55         stack += offset;
  56         *(unsigned long *) stack = data;
  57         return 0;
  58 }
  59
  60 static void ptrace_disable_singlestep(struct task_struct *child)
  61 {
  62         clear_tsk_thread_flag(child, TIF_SINGLESTEP);
  63
  64         /*
  65          * Ensure the UBC is not programmed at the next context switch.
  66          *
  67          * Normally this is not needed but there are sequences such as
  68          * singlestep, signal delivery, and continue that leave the
  69          * ubc_pc non-zero leading to spurious SIGTRAPs.
  70          */
  71         if (child->thread.ubc_pc != 0) {
  72                 ubc_usercnt -= 1;
  73                 child->thread.ubc_pc = 0;
  74         }
  75 }
  76
  77 /*
  78  * Called by kernel/ptrace.c when detaching..
  79  *
  80  * Make sure single step bits etc are not set.
  81  */
  82 void ptrace_disable(struct task_struct *child)
  83 {
  84         ptrace_disable_singlestep(child);
  85 }
  86
  87 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
  88 {
  89         struct user * dummy = NULL;
  90         int ret;
  91
  92         switch (request) {
  93         /* when I and D space are separate, these will need to be fixed. */
  94         case PTRACE_PEEKTEXT: /* read word at location addr. */
  95         case PTRACE_PEEKDATA:
  96                 ret = generic_ptrace_peekdata(child, addr, data);
  97                 break;
  98
  99         /* read the word at location addr in the USER area. */
 100         case PTRACE_PEEKUSR: {
 101                 unsigned long tmp;
 102
 103                 ret = -EIO;
 104                 if ((addr & 3) || addr < 0 ||
 105                     addr > sizeof(struct user) - 3)
 106                         break;
 107
 108                 if (addr < sizeof(struct pt_regs))
 109                         tmp = get_stack_long(child, addr);
 110                 else if (addr >= (long) &dummy->fpu &&
 111                          addr < (long) &dummy->u_fpvalid) {
 112                         if (!tsk_used_math(child)) {
 113                                 if (addr == (long)&dummy->fpu.fpscr)
 114                                         tmp = FPSCR_INIT;
 115                                 else
 116                                         tmp = 0;
 117                         } else
 118                                 tmp = ((long *)&child->thread.fpu)
 119                                         [(addr - (long)&dummy->fpu) >> 2];
 120                 } else if (addr == (long) &dummy->u_fpvalid)
 121                         tmp = !!tsk_used_math(child);
 122                 else
 123                         tmp = 0;
 124                 ret = put_user(tmp, (unsigned long __user *)data);
 125                 break;
 126         }
 127
 128         /* when I and D space are separate, this will have to be fixed. */
 129         case PTRACE_POKETEXT: /* write the word at location addr. */
 130         case PTRACE_POKEDATA:
 131                 ret = generic_ptrace_pokedata(child, addr, data);
 132                 break;
 133
 134         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 135                 ret = -EIO;
 136                 if ((addr & 3) || addr < 0 ||
 137                     addr > sizeof(struct user) - 3)
 138                         break;
 139
 140                 if (addr < sizeof(struct pt_regs))
 141                         ret = put_stack_long(child, addr, data);
 142                 else if (addr >= (long) &dummy->fpu &&
 143                          addr < (long) &dummy->u_fpvalid) {
 144                         set_stopped_child_used_math(child);
 145                         ((long *)&child->thread.fpu)
 146                                 [(addr - (long)&dummy->fpu) >> 2] = data;
 147                         ret = 0;
 148                 } else if (addr == (long) &dummy->u_fpvalid) {
 149                         conditional_stopped_child_used_math(data, child);
 150                         ret = 0;
 151                 }
 152                 break;
 153
 154         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 155         case PTRACE_CONT: { /* restart after signal. */
 156                 ret = -EIO;
 157                 if (!valid_signal(data))
 158                         break;
 159                 if (request == PTRACE_SYSCALL)
 160                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 161                 else
 162                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 163
 164                 ptrace_disable_singlestep(child);
 165
 166                 child->exit_code = data;
 167                 wake_up_process(child);
 168                 ret = 0;
 169                 break;
 170         }
 171
 172 /*
 173  * make the child exit.  Best I can do is send it a sigkill.
 174  * perhaps it should be put in the status that it wants to
 175  * exit.
 176  */
 177         case PTRACE_KILL: {
 178                 ret = 0;
 179                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 180                         break;
 181                 ptrace_disable_singlestep(child);
 182                 child->exit_code = SIGKILL;
 183                 wake_up_process(child);
 184                 break;
 185         }
 186
 187         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 188                 long pc;
 189                 struct pt_regs *regs = NULL;
 190
 191                 ret = -EIO;
 192                 if (!valid_signal(data))
 193                         break;
 194                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 195                 if ((child->ptrace & PT_DTRACE) == 0) {
 196                         /* Spurious delayed TF traps may occur */
 197                         child->ptrace |= PT_DTRACE;
 198                 }
 199
 200                 pc = get_stack_long(child, (long)&regs->pc);
 201
 202                 /* Next scheduling will set up UBC */
 203                 if (child->thread.ubc_pc == 0)
 204                         ubc_usercnt += 1;
 205                 child->thread.ubc_pc = pc;
 206
 207                 set_tsk_thread_flag(child, TIF_SINGLESTEP);
 208                 child->exit_code = data;
 209                 /* give it a chance to run. */
 210                 wake_up_process(child);
 211                 ret = 0;
 212                 break;
 213         }
 214
 215 #ifdef CONFIG_SH_DSP
 216         case PTRACE_GETDSPREGS: {
 217                 unsigned long dp;
 218
 219                 ret = -EIO;
 220                 dp = ((unsigned long) child) + THREAD_SIZE -
 221                          sizeof(struct pt_dspregs);
 222                 if (*((int *) (dp - 4)) == SR_FD) {
 223                         copy_to_user((void *)addr, (void *) dp,
 224                                 sizeof(struct pt_dspregs));
 225                         ret = 0;
 226                 }
 227                 break;
 228         }
 229
 230         case PTRACE_SETDSPREGS: {
 231                 unsigned long dp;
 232
 233                 ret = -EIO;
 234                 dp = ((unsigned long) child) + THREAD_SIZE -
 235                          sizeof(struct pt_dspregs);
 236                 if (*((int *) (dp - 4)) == SR_FD) {
 237                         copy_from_user((void *) dp, (void *)addr,
 238                                 sizeof(struct pt_dspregs));
 239                         ret = 0;
 240                 }
 241                 break;
 242         }
 243 #endif
 244         default:
 245                 ret = ptrace_request(child, request, addr, data);
 246                 break;
 247         }
 248
 249         return ret;
 250 }
 251
 252 asmlinkage void do_syscall_trace(struct pt_regs *regs, int entryexit)
 253 {
 254         struct task_struct *tsk = current;
 255
 256         if (unlikely(current->audit_context) && entryexit)
 257                 audit_syscall_exit(AUDITSC_RESULT(regs->regs[0]),
 258                                    regs->regs[0]);
 259
 260         if (!test_thread_flag(TIF_SYSCALL_TRACE) &&
 261             !test_thread_flag(TIF_SINGLESTEP))
 262                 goto out;
 263         if (!(tsk->ptrace & PT_PTRACED))
 264                 goto out;
 265
 266         /* the 0x80 provides a way for the tracing parent to distinguish
 267            between a syscall stop and SIGTRAP delivery */
 268         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) &&
 269                                  !test_thread_flag(TIF_SINGLESTEP) ? 0x80 : 0));
 270
 271         /*
 272          * this isn't the same as continuing with a signal, but it will do
 273          * for normal use.  strace only continues with a signal if the
 274          * stopping signal is not SIGTRAP.  -brl
 275          */
 276         if (tsk->exit_code) {
 277                 send_sig(tsk->exit_code, tsk, 1);
 278                 tsk->exit_code = 0;
 279         }
 280
 281 out:
 282         if (unlikely(current->audit_context) && !entryexit)
 283                 audit_syscall_entry(AUDIT_ARCH_SH, regs->regs[3],
 284                                     regs->regs[4], regs->regs[5],
 285                                     regs->regs[6], regs->regs[7]);
 286
 287 }