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 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs);
31
32 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs);
33
34 /*
35 * Copy the thread state to a regset that can be interpreted by userspace.
36 *
37 * It doesn't matter what our internal pt_regs structure looks like. The
38 * important thing is that we export a consistent view of the thread state
39 * to userspace. As such, we need to make sure that the regset remains
40 * ABI compatible as defined by the struct user_regs_struct:
41 *
42 * (Each item is a 32-bit word)
43 * r0 = 0 (exported for clarity)
44 * 31 GPRS r1-r31
45 * PC (Program counter)
46 * SR (Supervision register)
47 */
48 static int genregs_get(struct task_struct *target,
49 const struct user_regset *regset,
50 struct membuf to)
51 {
52 const struct pt_regs *regs = task_pt_regs(target);
53
54 /* r0 */
55 membuf_zero(&to, 4);
56 membuf_write(&to, regs->gpr + 1, 31 * 4);
57 membuf_store(&to, regs->pc);
58 return membuf_store(&to, regs->sr);
59 }
60
61 /*
62 * Set the thread state from a regset passed in via ptrace
63 */
64 static int genregs_set(struct task_struct *target,
65 const struct user_regset *regset,
66 unsigned int pos, unsigned int count,
67 const void *kbuf, const void __user * ubuf)
68 {
69 struct pt_regs *regs = task_pt_regs(target);
70 int ret;
71
72 /* ignore r0 */
73 user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, 0, 4);
74 /* r1 - r31 */
75 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
76 regs->gpr+1, 4, 4*32);
77 /* PC */
78 if (!ret)
79 ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
80 ®s->pc, 4*32, 4*33);
81 /*
82 * Skip SR and padding... userspace isn't allowed to changes bits in
83 * the Supervision register
84 */
85 if (!ret)
86 user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, 4*33, -1);
87
88 return ret;
89 }
90
91 #ifdef CONFIG_FPU
92 /*
93 * As OpenRISC shares GPRs and floating point registers we don't need to export
94 * the floating point registers again. So here we only export the fpcsr special
95 * purpose register.
96 */
97 static int fpregs_get(struct task_struct *target,
98 const struct user_regset *regset,
99 struct membuf to)
100 {
101 return membuf_store(&to, target->thread.fpcsr);
102 }
103
104 static int fpregs_set(struct task_struct *target,
105 const struct user_regset *regset,
106 unsigned int pos, unsigned int count,
107 const void *kbuf, const void __user *ubuf)
108 {
109 /* FPCSR */
110 return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
111 &target->thread.fpcsr, 0, 4);
112 }
113 #endif
114
115 /*
116 * Define the register sets available on OpenRISC under Linux
117 */
118 enum or1k_regset {
119 REGSET_GENERAL,
120 #ifdef CONFIG_FPU
121 REGSET_FPU,
122 #endif
123 };
124
125 static const struct user_regset or1k_regsets[] = {
126 [REGSET_GENERAL] = {
127 .core_note_type = NT_PRSTATUS,
128 .n = ELF_NGREG,
129 .size = sizeof(long),
130 .align = sizeof(long),
131 .regset_get = genregs_get,
132 .set = genregs_set,
133 },
134 #ifdef CONFIG_FPU
135 [REGSET_FPU] = {
136 .core_note_type = NT_PRFPREG,
137 .n = sizeof(struct __or1k_fpu_state) / sizeof(long),
138 .size = sizeof(long),
139 .align = sizeof(long),
140 .regset_get = fpregs_get,
141 .set = fpregs_set,
142 },
143 #endif
144 };
145
146 static const struct user_regset_view user_or1k_native_view = {
147 .name = "or1k",
148 .e_machine = EM_OPENRISC,
149 .regsets = or1k_regsets,
150 .n = ARRAY_SIZE(or1k_regsets),
151 };
152
153 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
154 {
155 return &user_or1k_native_view;
156 }
157
158 /*
159 * does not yet catch signals sent when the child dies.
160 * in exit.c or in signal.c.
161 */
162
163
164 /*
165 * Called by kernel/ptrace.c when detaching..
166 *
167 * Make sure the single step bit is not set.
168 */
169 void ptrace_disable(struct task_struct *child)
170 {
171 pr_debug("ptrace_disable(): TODO\n");
172
173 user_disable_single_step(child);
174 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
175 }
176
177 long arch_ptrace(struct task_struct *child, long request, unsigned long addr,
178 unsigned long data)
179 {
180 int ret;
181
182 switch (request) {
183 default:
184 ret = ptrace_request(child, request, addr, data);
185 break;
186 }
187
188 return ret;
189 }
190
191 /*
192 * Notification of system call entry/exit
193 * - triggered by current->work.syscall_trace
194 */
195 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
196 {
197 long ret = 0;
198
199 if (test_thread_flag(TIF_SYSCALL_TRACE) &&
200 ptrace_report_syscall_entry(regs))
201 /*
202 * Tracing decided this syscall should not happen.
203 * We'll return a bogus call number to get an ENOSYS
204 * error, but leave the original number in <something>.
205 */
206 ret = -1L;
207
208 audit_syscall_entry(regs->gpr[11], regs->gpr[3], regs->gpr[4],
209 regs->gpr[5], regs->gpr[6]);
210
211 return ret ? : regs->gpr[11];
212 }
213
214 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
215 {
216 int step;
217
218 audit_syscall_exit(regs);
219
220 step = test_thread_flag(TIF_SINGLESTEP);
221 if (step || test_thread_flag(TIF_SYSCALL_TRACE))
222 ptrace_report_syscall_exit(regs, step);
223 }
224
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