1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * linux/arch/unicore32/kernel/ptrace.c
4 *
5 * Code specific to PKUnity SoC and UniCore ISA
6 *
7 * Copyright (C) 2001-2010 GUAN Xue-tao
8 *
9 * By Ross Biro 1/23/92
10 */
11 #include <linux/kernel.h>
12 #include <linux/ptrace.h>
13 #include <linux/signal.h>
14 #include <linux/uaccess.h>
15 #include <linux/sched/task_stack.h>
16
17 /*
18 * this routine will get a word off of the processes privileged stack.
19 * the offset is how far from the base addr as stored in the THREAD.
20 * this routine assumes that all the privileged stacks are in our
21 * data space.
22 */
get_user_reg(struct task_struct * task,int offset)23 static inline long get_user_reg(struct task_struct *task, int offset)
24 {
25 return task_pt_regs(task)->uregs[offset];
26 }
27
28 /*
29 * this routine will put a word on the processes privileged stack.
30 * the offset is how far from the base addr as stored in the THREAD.
31 * this routine assumes that all the privileged stacks are in our
32 * data space.
33 */
34 static inline int
put_user_reg(struct task_struct * task,int offset,long data)35 put_user_reg(struct task_struct *task, int offset, long data)
36 {
37 struct pt_regs newregs, *regs = task_pt_regs(task);
38 int ret = -EINVAL;
39
40 newregs = *regs;
41 newregs.uregs[offset] = data;
42
43 if (valid_user_regs(&newregs)) {
44 regs->uregs[offset] = data;
45 ret = 0;
46 }
47
48 return ret;
49 }
50
51 /*
52 * Called by kernel/ptrace.c when detaching..
53 */
ptrace_disable(struct task_struct * child)54 void ptrace_disable(struct task_struct *child)
55 {
56 }
57
58 /*
59 * We actually access the pt_regs stored on the kernel stack.
60 */
ptrace_read_user(struct task_struct * tsk,unsigned long off,unsigned long __user * ret)61 static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
62 unsigned long __user *ret)
63 {
64 unsigned long tmp;
65
66 tmp = 0;
67 if (off < sizeof(struct pt_regs))
68 tmp = get_user_reg(tsk, off >> 2);
69
70 return put_user(tmp, ret);
71 }
72
73 /*
74 * We actually access the pt_regs stored on the kernel stack.
75 */
ptrace_write_user(struct task_struct * tsk,unsigned long off,unsigned long val)76 static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
77 unsigned long val)
78 {
79 if (off >= sizeof(struct pt_regs))
80 return 0;
81
82 return put_user_reg(tsk, off >> 2, val);
83 }
84
arch_ptrace(struct task_struct * child,long request,unsigned long addr,unsigned long data)85 long arch_ptrace(struct task_struct *child, long request,
86 unsigned long addr, unsigned long data)
87 {
88 int ret;
89 unsigned long __user *datap = (unsigned long __user *) data;
90
91 switch (request) {
92 case PTRACE_PEEKUSR:
93 ret = ptrace_read_user(child, addr, datap);
94 break;
95
96 case PTRACE_POKEUSR:
97 ret = ptrace_write_user(child, addr, data);
98 break;
99
100 case PTRACE_GET_THREAD_AREA:
101 ret = put_user(task_pt_regs(child)->UCreg_16,
102 datap);
103 break;
104
105 default:
106 ret = ptrace_request(child, request, addr, data);
107 break;
108 }
109
110 return ret;
111 }
112
syscall_trace(int why,struct pt_regs * regs,int scno)113 asmlinkage int syscall_trace(int why, struct pt_regs *regs, int scno)
114 {
115 unsigned long ip;
116
117 if (!test_thread_flag(TIF_SYSCALL_TRACE))
118 return scno;
119 if (!(current->ptrace & PT_PTRACED))
120 return scno;
121
122 /*
123 * Save IP. IP is used to denote syscall entry/exit:
124 * IP = 0 -> entry, = 1 -> exit
125 */
126 ip = regs->UCreg_ip;
127 regs->UCreg_ip = why;
128
129 current_thread_info()->syscall = scno;
130
131 /* the 0x80 provides a way for the tracing parent to distinguish
132 between a syscall stop and SIGTRAP delivery */
133 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
134 ? 0x80 : 0));
135 /*
136 * this isn't the same as continuing with a signal, but it will do
137 * for normal use. strace only continues with a signal if the
138 * stopping signal is not SIGTRAP. -brl
139 */
140 if (current->exit_code) {
141 send_sig(current->exit_code, current, 1);
142 current->exit_code = 0;
143 }
144 regs->UCreg_ip = ip;
145
146 return current_thread_info()->syscall;
147 }
148