arch/unicore32/kernel/ptrace.c

   1 /*
   2  * linux/arch/unicore32/kernel/ptrace.c
   3  *
   4  * Code specific to PKUnity SoC and UniCore ISA
   5  *
   6  * Copyright (C) 2001-2010 GUAN Xue-tao
   7  *
   8  * By Ross Biro 1/23/92
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  */
  14 #include <linux/kernel.h>
  15 #include <linux/ptrace.h>
  16 #include <linux/signal.h>
  17 #include <linux/uaccess.h>
  18
  19 /*
  20  * this routine will get a word off of the processes privileged stack.
  21  * the offset is how far from the base addr as stored in the THREAD.
  22  * this routine assumes that all the privileged stacks are in our
  23  * data space.
  24  */
  25 static inline long get_user_reg(struct task_struct *task, int offset)
  26 {
  27         return task_pt_regs(task)->uregs[offset];
  28 }
  29
  30 /*
  31  * this routine will put a word on the processes privileged stack.
  32  * the offset is how far from the base addr as stored in the THREAD.
  33  * this routine assumes that all the privileged stacks are in our
  34  * data space.
  35  */
  36 static inline int
  37 put_user_reg(struct task_struct *task, int offset, long data)
  38 {
  39         struct pt_regs newregs, *regs = task_pt_regs(task);
  40         int ret = -EINVAL;
  41
  42         newregs = *regs;
  43         newregs.uregs[offset] = data;
  44
  45         if (valid_user_regs(&newregs)) {
  46                 regs->uregs[offset] = data;
  47                 ret = 0;
  48         }
  49
  50         return ret;
  51 }
  52
  53 /*
  54  * Called by kernel/ptrace.c when detaching..
  55  */
  56 void ptrace_disable(struct task_struct *child)
  57 {
  58 }
  59
  60 /*
  61  * We actually access the pt_regs stored on the kernel stack.
  62  */
  63 static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
  64                             unsigned long __user *ret)
  65 {
  66         unsigned long tmp;
  67
  68         tmp = 0;
  69         if (off < sizeof(struct pt_regs))
  70                 tmp = get_user_reg(tsk, off >> 2);
  71
  72         return put_user(tmp, ret);
  73 }
  74
  75 /*
  76  * We actually access the pt_regs stored on the kernel stack.
  77  */
  78 static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
  79                              unsigned long val)
  80 {
  81         if (off >= sizeof(struct pt_regs))
  82                 return 0;
  83
  84         return put_user_reg(tsk, off >> 2, val);
  85 }
  86
  87 long arch_ptrace(struct task_struct *child, long request,
  88                  unsigned long addr, unsigned long data)
  89 {
  90         int ret;
  91         unsigned long __user *datap = (unsigned long __user *) data;
  92
  93         switch (request) {
  94         case PTRACE_PEEKUSR:
  95                 ret = ptrace_read_user(child, addr, datap);
  96                 break;
  97
  98         case PTRACE_POKEUSR:
  99                 ret = ptrace_write_user(child, addr, data);
 100                 break;
 101
 102         case PTRACE_GET_THREAD_AREA:
 103                 ret = put_user(task_pt_regs(child)->UCreg_16,
 104                                datap);
 105                 break;
 106
 107         default:
 108                 ret = ptrace_request(child, request, addr, data);
 109                 break;
 110         }
 111
 112         return ret;
 113 }
 114
 115 asmlinkage int syscall_trace(int why, struct pt_regs *regs, int scno)
 116 {
 117         unsigned long ip;
 118
 119         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 120                 return scno;
 121         if (!(current->ptrace & PT_PTRACED))
 122                 return scno;
 123
 124         /*
 125          * Save IP.  IP is used to denote syscall entry/exit:
 126          *  IP = 0 -> entry, = 1 -> exit
 127          */
 128         ip = regs->UCreg_ip;
 129         regs->UCreg_ip = why;
 130
 131         current_thread_info()->syscall = scno;
 132
 133         /* the 0x80 provides a way for the tracing parent to distinguish
 134            between a syscall stop and SIGTRAP delivery */
 135         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 136                                  ? 0x80 : 0));
 137         /*
 138          * this isn't the same as continuing with a signal, but it will do
 139          * for normal use.  strace only continues with a signal if the
 140          * stopping signal is not SIGTRAP.  -brl
 141          */
 142         if (current->exit_code) {
 143                 send_sig(current->exit_code, current, 1);
 144                 current->exit_code = 0;
 145         }
 146         regs->UCreg_ip = ip;
 147
 148         return current_thread_info()->syscall;
 149 }