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