arch/tile/kernel/ptrace.c

   1 /*
   2  * Copyright 2010 Tilera Corporation. All Rights Reserved.
   3  *
   4  *   This program is free software; you can redistribute it and/or
   5  *   modify it under the terms of the GNU General Public License
   6  *   as published by the Free Software Foundation, version 2.
   7  *
   8  *   This program is distributed in the hope that it will be useful, but
   9  *   WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  11  *   NON INFRINGEMENT.  See the GNU General Public License for
  12  *   more details.
  13  *
  14  * Copied from i386: Ross Biro 1/23/92
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/ptrace.h>
  19 #include <linux/kprobes.h>
  20 #include <linux/compat.h>
  21 #include <linux/uaccess.h>
  22 #include <asm/traps.h>
  23
  24 void user_enable_single_step(struct task_struct *child)
  25 {
  26         set_tsk_thread_flag(child, TIF_SINGLESTEP);
  27 }
  28
  29 void user_disable_single_step(struct task_struct *child)
  30 {
  31         clear_tsk_thread_flag(child, TIF_SINGLESTEP);
  32 }
  33
  34 /*
  35  * Called by kernel/ptrace.c when detaching..
  36  */
  37 void ptrace_disable(struct task_struct *child)
  38 {
  39         clear_tsk_thread_flag(child, TIF_SINGLESTEP);
  40
  41         /*
  42          * These two are currently unused, but will be set by arch_ptrace()
  43          * and used in the syscall assembly when we do support them.
  44          */
  45         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
  46 }
  47
  48 long arch_ptrace(struct task_struct *child, long request,
  49                  unsigned long addr, unsigned long data)
  50 {
  51         unsigned long __user *datap = (long __user __force *)data;
  52         unsigned long tmp;
  53         long ret = -EIO;
  54         char *childreg;
  55         struct pt_regs copyregs;
  56         int ex1_offset;
  57
  58         switch (request) {
  59
  60         case PTRACE_PEEKUSR:  /* Read register from pt_regs. */
  61                 if (addr >= PTREGS_SIZE)
  62                         break;
  63                 childreg = (char *)task_pt_regs(child) + addr;
  64 #ifdef CONFIG_COMPAT
  65                 if (is_compat_task()) {
  66                         if (addr & (sizeof(compat_long_t)-1))
  67                                 break;
  68                         ret = put_user(*(compat_long_t *)childreg,
  69                                        (compat_long_t __user *)datap);
  70                 } else
  71 #endif
  72                 {
  73                         if (addr & (sizeof(long)-1))
  74                                 break;
  75                         ret = put_user(*(long *)childreg, datap);
  76                 }
  77                 break;
  78
  79         case PTRACE_POKEUSR:  /* Write register in pt_regs. */
  80                 if (addr >= PTREGS_SIZE)
  81                         break;
  82                 childreg = (char *)task_pt_regs(child) + addr;
  83
  84                 /* Guard against overwrites of the privilege level. */
  85                 ex1_offset = PTREGS_OFFSET_EX1;
  86 #if defined(CONFIG_COMPAT) && defined(__BIG_ENDIAN)
  87                 if (is_compat_task())   /* point at low word */
  88                         ex1_offset += sizeof(compat_long_t);
  89 #endif
  90                 if (addr == ex1_offset)
  91                         data = PL_ICS_EX1(USER_PL, EX1_ICS(data));
  92
  93 #ifdef CONFIG_COMPAT
  94                 if (is_compat_task()) {
  95                         if (addr & (sizeof(compat_long_t)-1))
  96                                 break;
  97                         *(compat_long_t *)childreg = data;
  98                 } else
  99 #endif
 100                 {
 101                         if (addr & (sizeof(long)-1))
 102                                 break;
 103                         *(long *)childreg = data;
 104                 }
 105                 ret = 0;
 106                 break;
 107
 108         case PTRACE_GETREGS:  /* Get all registers from the child. */
 109                 if (copy_to_user(datap, task_pt_regs(child),
 110                                  sizeof(struct pt_regs)) == 0) {
 111                         ret = 0;
 112                 }
 113                 break;
 114
 115         case PTRACE_SETREGS:  /* Set all registers in the child. */
 116                 if (copy_from_user(&copyregs, datap,
 117                                    sizeof(struct pt_regs)) == 0) {
 118                         copyregs.ex1 =
 119                                 PL_ICS_EX1(USER_PL, EX1_ICS(copyregs.ex1));
 120                         *task_pt_regs(child) = copyregs;
 121                         ret = 0;
 122                 }
 123                 break;
 124
 125         case PTRACE_GETFPREGS:  /* Get the child FPU state. */
 126         case PTRACE_SETFPREGS:  /* Set the child FPU state. */
 127                 break;
 128
 129         case PTRACE_SETOPTIONS:
 130                 /* Support TILE-specific ptrace options. */
 131                 child->ptrace &= ~PT_TRACE_MASK_TILE;
 132                 tmp = data & PTRACE_O_MASK_TILE;
 133                 data &= ~PTRACE_O_MASK_TILE;
 134                 ret = ptrace_request(child, request, addr, data);
 135                 if (tmp & PTRACE_O_TRACEMIGRATE)
 136                         child->ptrace |= PT_TRACE_MIGRATE;
 137                 break;
 138
 139         default:
 140 #ifdef CONFIG_COMPAT
 141                 if (task_thread_info(current)->status & TS_COMPAT) {
 142                         ret = compat_ptrace_request(child, request,
 143                                                     addr, data);
 144                         break;
 145                 }
 146 #endif
 147                 ret = ptrace_request(child, request, addr, data);
 148                 break;
 149         }
 150
 151         return ret;
 152 }
 153
 154 #ifdef CONFIG_COMPAT
 155 /* Not used; we handle compat issues in arch_ptrace() directly. */
 156 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
 157                                compat_ulong_t addr, compat_ulong_t data)
 158 {
 159         BUG();
 160 }
 161 #endif
 162
 163 void do_syscall_trace(void)
 164 {
 165         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 166                 return;
 167
 168         if (!(current->ptrace & PT_PTRACED))
 169                 return;
 170
 171         /*
 172          * The 0x80 provides a way for the tracing parent to distinguish
 173          * between a syscall stop and SIGTRAP delivery
 174          */
 175         ptrace_notify(SIGTRAP|((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));
 176
 177         /*
 178          * this isn't the same as continuing with a signal, but it will do
 179          * for normal use.  strace only continues with a signal if the
 180          * stopping signal is not SIGTRAP.  -brl
 181          */
 182         if (current->exit_code) {
 183                 send_sig(current->exit_code, current, 1);
 184                 current->exit_code = 0;
 185         }
 186 }
 187
 188 void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code)
 189 {
 190         struct siginfo info;
 191
 192         memset(&info, 0, sizeof(info));
 193         info.si_signo = SIGTRAP;
 194         info.si_code  = TRAP_BRKPT;
 195         info.si_addr  = (void __user *) regs->pc;
 196
 197         /* Send us the fakey SIGTRAP */
 198         force_sig_info(SIGTRAP, &info, tsk);
 199 }
 200
 201 /* Handle synthetic interrupt delivered only by the simulator. */
 202 void __kprobes do_breakpoint(struct pt_regs* regs, int fault_num)
 203 {
 204         send_sigtrap(current, regs, fault_num);
 205 }