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 */
get_user_reg(struct task_struct * task,int offset)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
put_user_reg(struct task_struct * task,int offset,long data)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 */
ptrace_disable(struct task_struct * child)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 */
ptrace_read_user(struct task_struct * tsk,unsigned long off,unsigned long __user * ret)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 */
ptrace_write_user(struct task_struct * tsk,unsigned long off,unsigned long val)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
arch_ptrace(struct task_struct * child,long request,unsigned long addr,unsigned long data)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
syscall_trace(int why,struct pt_regs * regs,int scno)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 }
150