1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * OpenRISC ptrace.c
4 *
5 * Linux architectural port borrowing liberally from similar works of
6 * others. All original copyrights apply as per the original source
7 * declaration.
8 *
9 * Modifications for the OpenRISC architecture:
10 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
11 * Copyright (C) 2005 Gyorgy Jeney <nog@bsemi.com>
12 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
13 */
14
15 #include <linux/kernel.h>
16 #include <linux/sched.h>
17 #include <linux/sched/task_stack.h>
18 #include <linux/string.h>
19
20 #include <linux/mm.h>
21 #include <linux/errno.h>
22 #include <linux/ptrace.h>
23 #include <linux/audit.h>
24 #include <linux/regset.h>
25 #include <linux/tracehook.h>
26 #include <linux/elf.h>
27
28 #include <asm/thread_info.h>
29 #include <asm/page.h>
30
31 /*
32 * Copy the thread state to a regset that can be interpreted by userspace.
33 *
34 * It doesn't matter what our internal pt_regs structure looks like. The
35 * important thing is that we export a consistent view of the thread state
36 * to userspace. As such, we need to make sure that the regset remains
37 * ABI compatible as defined by the struct user_regs_struct:
38 *
39 * (Each item is a 32-bit word)
40 * r0 = 0 (exported for clarity)
41 * 31 GPRS r1-r31
42 * PC (Program counter)
43 * SR (Supervision register)
44 */
genregs_get(struct task_struct * target,const struct user_regset * regset,struct membuf to)45 static int genregs_get(struct task_struct *target,
46 const struct user_regset *regset,
47 struct membuf to)
48 {
49 const struct pt_regs *regs = task_pt_regs(target);
50
51 /* r0 */
52 membuf_zero(&to, 4);
53 membuf_write(&to, regs->gpr + 1, 31 * 4);
54 membuf_store(&to, regs->pc);
55 return membuf_store(&to, regs->sr);
56 }
57
58 /*
59 * Set the thread state from a regset passed in via ptrace
60 */
genregs_set(struct task_struct * target,const struct user_regset * regset,unsigned int pos,unsigned int count,const void * kbuf,const void __user * ubuf)61 static int genregs_set(struct task_struct *target,
62 const struct user_regset *regset,
63 unsigned int pos, unsigned int count,
64 const void *kbuf, const void __user * ubuf)
65 {
66 struct pt_regs *regs = task_pt_regs(target);
67 int ret;
68
69 /* ignore r0 */
70 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, 0, 4);
71 /* r1 - r31 */
72 if (!ret)
73 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
74 regs->gpr+1, 4, 4*32);
75 /* PC */
76 if (!ret)
77 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
78 ®s->pc, 4*32, 4*33);
79 /*
80 * Skip SR and padding... userspace isn't allowed to changes bits in
81 * the Supervision register
82 */
83 if (!ret)
84 ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
85 4*33, -1);
86
87 return ret;
88 }
89
90 /*
91 * Define the register sets available on OpenRISC under Linux
92 */
93 enum or1k_regset {
94 REGSET_GENERAL,
95 };
96
97 static const struct user_regset or1k_regsets[] = {
98 [REGSET_GENERAL] = {
99 .core_note_type = NT_PRSTATUS,
100 .n = ELF_NGREG,
101 .size = sizeof(long),
102 .align = sizeof(long),
103 .regset_get = genregs_get,
104 .set = genregs_set,
105 },
106 };
107
108 static const struct user_regset_view user_or1k_native_view = {
109 .name = "or1k",
110 .e_machine = EM_OPENRISC,
111 .regsets = or1k_regsets,
112 .n = ARRAY_SIZE(or1k_regsets),
113 };
114
task_user_regset_view(struct task_struct * task)115 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
116 {
117 return &user_or1k_native_view;
118 }
119
120 /*
121 * does not yet catch signals sent when the child dies.
122 * in exit.c or in signal.c.
123 */
124
125
126 /*
127 * Called by kernel/ptrace.c when detaching..
128 *
129 * Make sure the single step bit is not set.
130 */
ptrace_disable(struct task_struct * child)131 void ptrace_disable(struct task_struct *child)
132 {
133 pr_debug("ptrace_disable(): TODO\n");
134
135 user_disable_single_step(child);
136 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
137 }
138
arch_ptrace(struct task_struct * child,long request,unsigned long addr,unsigned long data)139 long arch_ptrace(struct task_struct *child, long request, unsigned long addr,
140 unsigned long data)
141 {
142 int ret;
143
144 switch (request) {
145 default:
146 ret = ptrace_request(child, request, addr, data);
147 break;
148 }
149
150 return ret;
151 }
152
153 /*
154 * Notification of system call entry/exit
155 * - triggered by current->work.syscall_trace
156 */
do_syscall_trace_enter(struct pt_regs * regs)157 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
158 {
159 long ret = 0;
160
161 if (test_thread_flag(TIF_SYSCALL_TRACE) &&
162 tracehook_report_syscall_entry(regs))
163 /*
164 * Tracing decided this syscall should not happen.
165 * We'll return a bogus call number to get an ENOSYS
166 * error, but leave the original number in <something>.
167 */
168 ret = -1L;
169
170 audit_syscall_entry(regs->gpr[11], regs->gpr[3], regs->gpr[4],
171 regs->gpr[5], regs->gpr[6]);
172
173 return ret ? : regs->gpr[11];
174 }
175
do_syscall_trace_leave(struct pt_regs * regs)176 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
177 {
178 int step;
179
180 audit_syscall_exit(regs);
181
182 step = test_thread_flag(TIF_SINGLESTEP);
183 if (step || test_thread_flag(TIF_SYSCALL_TRACE))
184 tracehook_report_syscall_exit(regs, step);
185 }
186
