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 /*
  49  * Get registers from task and ready the result for userspace.
  50  * Note that we localize the API issues to getregs() and putregs() at
  51  * some cost in performance, e.g. we need a full pt_regs copy for
  52  * PEEKUSR, and two copies for POKEUSR.  But in general we expect
  53  * GETREGS/PUTREGS to be the API of choice anyway.
  54  */
  55 static char *getregs(struct task_struct *child, struct pt_regs *uregs)
  56 {
  57         *uregs = *task_pt_regs(child);
  58
  59         /* Set up flags ABI bits. */
  60         uregs->flags = 0;
  61 #ifdef CONFIG_COMPAT
  62         if (task_thread_info(child)->status & TS_COMPAT)
  63                 uregs->flags |= PT_FLAGS_COMPAT;
  64 #endif
  65
  66         return (char *)uregs;
  67 }
  68
  69 /* Put registers back to task. */
  70 static void putregs(struct task_struct *child, struct pt_regs *uregs)
  71 {
  72         struct pt_regs *regs = task_pt_regs(child);
  73
  74         /* Don't allow overwriting the kernel-internal flags word. */
  75         uregs->flags = regs->flags;
  76
  77         /* Only allow setting the ICS bit in the ex1 word. */
  78         uregs->ex1 = PL_ICS_EX1(USER_PL, EX1_ICS(uregs->ex1));
  79
  80         *regs = *uregs;
  81 }
  82
  83 long arch_ptrace(struct task_struct *child, long request,
  84                  unsigned long addr, unsigned long data)
  85 {
  86         unsigned long __user *datap = (long __user __force *)data;
  87         unsigned long tmp;
  88         long ret = -EIO;
  89         char *childreg;
  90         struct pt_regs copyregs;
  91
  92         switch (request) {
  93
  94         case PTRACE_PEEKUSR:  /* Read register from pt_regs. */
  95                 if (addr >= PTREGS_SIZE)
  96                         break;
  97                 childreg = getregs(child, &copyregs) + addr;
  98 #ifdef CONFIG_COMPAT
  99                 if (is_compat_task()) {
 100                         if (addr & (sizeof(compat_long_t)-1))
 101                                 break;
 102                         ret = put_user(*(compat_long_t *)childreg,
 103                                        (compat_long_t __user *)datap);
 104                 } else
 105 #endif
 106                 {
 107                         if (addr & (sizeof(long)-1))
 108                                 break;
 109                         ret = put_user(*(long *)childreg, datap);
 110                 }
 111                 break;
 112
 113         case PTRACE_POKEUSR:  /* Write register in pt_regs. */
 114                 if (addr >= PTREGS_SIZE)
 115                         break;
 116                 childreg = getregs(child, &copyregs) + addr;
 117 #ifdef CONFIG_COMPAT
 118                 if (is_compat_task()) {
 119                         if (addr & (sizeof(compat_long_t)-1))
 120                                 break;
 121                         *(compat_long_t *)childreg = data;
 122                 } else
 123 #endif
 124                 {
 125                         if (addr & (sizeof(long)-1))
 126                                 break;
 127                         *(long *)childreg = data;
 128                 }
 129                 putregs(child, &copyregs);
 130                 ret = 0;
 131                 break;
 132
 133         case PTRACE_GETREGS:  /* Get all registers from the child. */
 134                 if (copy_to_user(datap, getregs(child, &copyregs),
 135                                  sizeof(struct pt_regs)) == 0) {
 136                         ret = 0;
 137                 }
 138                 break;
 139
 140         case PTRACE_SETREGS:  /* Set all registers in the child. */
 141                 if (copy_from_user(&copyregs, datap,
 142                                    sizeof(struct pt_regs)) == 0) {
 143                         putregs(child, &copyregs);
 144                         ret = 0;
 145                 }
 146                 break;
 147
 148         case PTRACE_GETFPREGS:  /* Get the child FPU state. */
 149         case PTRACE_SETFPREGS:  /* Set the child FPU state. */
 150                 break;
 151
 152         case PTRACE_SETOPTIONS:
 153                 /* Support TILE-specific ptrace options. */
 154                 child->ptrace &= ~PT_TRACE_MASK_TILE;
 155                 tmp = data & PTRACE_O_MASK_TILE;
 156                 data &= ~PTRACE_O_MASK_TILE;
 157                 ret = ptrace_request(child, request, addr, data);
 158                 if (tmp & PTRACE_O_TRACEMIGRATE)
 159                         child->ptrace |= PT_TRACE_MIGRATE;
 160                 break;
 161
 162         default:
 163 #ifdef CONFIG_COMPAT
 164                 if (task_thread_info(current)->status & TS_COMPAT) {
 165                         ret = compat_ptrace_request(child, request,
 166                                                     addr, data);
 167                         break;
 168                 }
 169 #endif
 170                 ret = ptrace_request(child, request, addr, data);
 171                 break;
 172         }
 173
 174         return ret;
 175 }
 176
 177 #ifdef CONFIG_COMPAT
 178 /* Not used; we handle compat issues in arch_ptrace() directly. */
 179 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
 180                                compat_ulong_t addr, compat_ulong_t data)
 181 {
 182         BUG();
 183 }
 184 #endif
 185
 186 void do_syscall_trace(void)
 187 {
 188         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 189                 return;
 190
 191         if (!(current->ptrace & PT_PTRACED))
 192                 return;
 193
 194         /*
 195          * The 0x80 provides a way for the tracing parent to distinguish
 196          * between a syscall stop and SIGTRAP delivery
 197          */
 198         ptrace_notify(SIGTRAP|((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));
 199
 200         /*
 201          * this isn't the same as continuing with a signal, but it will do
 202          * for normal use.  strace only continues with a signal if the
 203          * stopping signal is not SIGTRAP.  -brl
 204          */
 205         if (current->exit_code) {
 206                 send_sig(current->exit_code, current, 1);
 207                 current->exit_code = 0;
 208         }
 209 }
 210
 211 void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code)
 212 {
 213         struct siginfo info;
 214
 215         memset(&info, 0, sizeof(info));
 216         info.si_signo = SIGTRAP;
 217         info.si_code  = TRAP_BRKPT;
 218         info.si_addr  = (void __user *) regs->pc;
 219
 220         /* Send us the fakey SIGTRAP */
 221         force_sig_info(SIGTRAP, &info, tsk);
 222 }
 223
 224 /* Handle synthetic interrupt delivered only by the simulator. */
 225 void __kprobes do_breakpoint(struct pt_regs* regs, int fault_num)
 226 {
 227         send_sigtrap(current, regs, fault_num);
 228 }