1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 */
5
6#include <linux/audit.h>
7#include <linux/ptrace.h>
8#include <linux/sched.h>
9#include <linux/uaccess.h>
10#include <asm/ptrace-abi.h>
11
12#define CREATE_TRACE_POINTS
13#include <trace/events/syscalls.h>
14
15void user_enable_single_step(struct task_struct *child)
16{
17 set_tsk_thread_flag(tsk: child, TIF_SINGLESTEP);
18
19#ifdef SUBARCH_SET_SINGLESTEPPING
20 SUBARCH_SET_SINGLESTEPPING(child, 1);
21#endif
22}
23
24void user_disable_single_step(struct task_struct *child)
25{
26 clear_tsk_thread_flag(tsk: child, TIF_SINGLESTEP);
27
28#ifdef SUBARCH_SET_SINGLESTEPPING
29 SUBARCH_SET_SINGLESTEPPING(child, 0);
30#endif
31}
32
33/*
34 * Called by kernel/ptrace.c when detaching..
35 */
36void ptrace_disable(struct task_struct *child)
37{
38 user_disable_single_step(child);
39}
40
41long arch_ptrace(struct task_struct *child, long request,
42 unsigned long addr, unsigned long data)
43{
44 int i, ret;
45 unsigned long __user *p = (void __user *)data;
46 void __user *vp = p;
47
48 switch (request) {
49 /* read the word at location addr in the USER area. */
50 case PTRACE_PEEKUSR:
51 ret = peek_user(child, addr, data);
52 break;
53
54 /* write the word at location addr in the USER area */
55 case PTRACE_POKEUSR:
56 ret = poke_user(child, addr, data);
57 break;
58
59 case PTRACE_SYSEMU:
60 case PTRACE_SYSEMU_SINGLESTEP:
61 ret = -EIO;
62 break;
63
64#ifdef PTRACE_GETREGS
65 case PTRACE_GETREGS: { /* Get all gp regs from the child. */
66 if (!access_ok(p, MAX_REG_OFFSET)) {
67 ret = -EIO;
68 break;
69 }
70 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
71 __put_user(getreg(child, i), p);
72 p++;
73 }
74 ret = 0;
75 break;
76 }
77#endif
78#ifdef PTRACE_SETREGS
79 case PTRACE_SETREGS: { /* Set all gp regs in the child. */
80 unsigned long tmp = 0;
81 if (!access_ok(p, MAX_REG_OFFSET)) {
82 ret = -EIO;
83 break;
84 }
85 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
86 __get_user(tmp, p);
87 putreg(child, i, tmp);
88 p++;
89 }
90 ret = 0;
91 break;
92 }
93#endif
94 case PTRACE_GET_THREAD_AREA:
95 ret = ptrace_get_thread_area(child, addr, vp);
96 break;
97
98 case PTRACE_SET_THREAD_AREA:
99 ret = ptrace_set_thread_area(child, addr, vp);
100 break;
101
102 default:
103 ret = ptrace_request(child, request, addr, data);
104 if (ret == -EIO)
105 ret = subarch_ptrace(child, request, addr, data);
106 break;
107 }
108
109 return ret;
110}
111
112static void send_sigtrap(struct uml_pt_regs *regs, int error_code)
113{
114 /* Send us the fake SIGTRAP */
115 force_sig_fault(SIGTRAP, TRAP_BRKPT,
116 /* User-mode eip? */
117 addr: UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL);
118}
119
120/*
121 * XXX Check TIF_SINGLESTEP for singlestepping check and
122 * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
123 */
124int syscall_trace_enter(struct pt_regs *regs)
125{
126 audit_syscall_entry(major: UPT_SYSCALL_NR(&regs->regs),
127 a0: UPT_SYSCALL_ARG1(&regs->regs),
128 a1: UPT_SYSCALL_ARG2(&regs->regs),
129 a2: UPT_SYSCALL_ARG3(&regs->regs),
130 a3: UPT_SYSCALL_ARG4(&regs->regs));
131
132 if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
133 trace_sys_enter(regs, id: UPT_SYSCALL_NR(&regs->regs));
134
135 if (!test_thread_flag(TIF_SYSCALL_TRACE))
136 return 0;
137
138 return ptrace_report_syscall_entry(regs);
139}
140
141void syscall_trace_leave(struct pt_regs *regs)
142{
143 int ptraced = current->ptrace;
144
145 audit_syscall_exit(pt_regs: regs);
146
147 /* Fake a debug trap */
148 if (test_thread_flag(TIF_SINGLESTEP))
149 send_sigtrap(regs: &regs->regs, error_code: 0);
150
151 if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
152 trace_sys_exit(regs, ret: PT_REGS_SYSCALL_RET(regs));
153
154 if (!test_thread_flag(TIF_SYSCALL_TRACE))
155 return;
156
157 ptrace_report_syscall_exit(regs, step: 0);
158 /* force do_signal() --> is_syscall() */
159 if (ptraced & PT_PTRACED)
160 set_thread_flag(TIF_SIGPENDING);
161}
162

source code of linux/arch/um/kernel/ptrace.c