1/*
2 * OpenRISC ptrace.c
3 *
4 * Linux architectural port borrowing liberally from similar works of
5 * others.  All original copyrights apply as per the original source
6 * declaration.
7 *
8 * Modifications for the OpenRISC architecture:
9 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
10 * Copyright (C) 2005 Gyorgy Jeney <nog@bsemi.com>
11 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
12 *
13 *      This program is free software; you can redistribute it and/or
14 *      modify it under the terms of the GNU General Public License
15 *      as published by the Free Software Foundation; either version
16 *      2 of the License, or (at your option) any later version.
17 */
18
19#include <stddef.h>
20#include <linux/kernel.h>
21#include <linux/sched.h>
22#include <linux/string.h>
23
24#include <linux/mm.h>
25#include <linux/errno.h>
26#include <linux/ptrace.h>
27#include <linux/audit.h>
28#include <linux/regset.h>
29#include <linux/tracehook.h>
30#include <linux/elf.h>
31
32#include <asm/thread_info.h>
33#include <asm/segment.h>
34#include <asm/page.h>
35#include <asm/pgtable.h>
36
37/*
38 * Copy the thread state to a regset that can be interpreted by userspace.
39 *
40 * It doesn't matter what our internal pt_regs structure looks like.  The
41 * important thing is that we export a consistent view of the thread state
42 * to userspace.  As such, we need to make sure that the regset remains
43 * ABI compatible as defined by the struct user_regs_struct:
44 *
45 * (Each item is a 32-bit word)
46 * r0 = 0 (exported for clarity)
47 * 31 GPRS r1-r31
48 * PC (Program counter)
49 * SR (Supervision register)
50 */
51static int genregs_get(struct task_struct *target,
52		       const struct user_regset *regset,
53		       unsigned int pos, unsigned int count,
54		       void *kbuf, void __user * ubuf)
55{
56	const struct pt_regs *regs = task_pt_regs(target);
57	int ret;
58
59	/* r0 */
60	ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf, 0, 4);
61
62	if (!ret)
63		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
64					  regs->gpr+1, 4, 4*32);
65	if (!ret)
66		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
67				  &regs->pc, 4*32, 4*33);
68	if (!ret)
69		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
70					  &regs->sr, 4*33, 4*34);
71	if (!ret)
72		ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
73					       4*34, -1);
74
75	return ret;
76}
77
78/*
79 * Set the thread state from a regset passed in via ptrace
80 */
81static int genregs_set(struct task_struct *target,
82		       const struct user_regset *regset,
83		       unsigned int pos, unsigned int count,
84		       const void *kbuf, const void __user * ubuf)
85{
86	struct pt_regs *regs = task_pt_regs(target);
87	int ret;
88
89	/* ignore r0 */
90	ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, 0, 4);
91	/* r1 - r31 */
92	if (!ret)
93		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
94					 regs->gpr+1, 4, 4*32);
95	/* PC */
96	if (!ret)
97		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
98				 &regs->pc, 4*32, 4*33);
99	/*
100	 * Skip SR and padding... userspace isn't allowed to changes bits in
101	 * the Supervision register
102	 */
103	if (!ret)
104		ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
105						4*33, -1);
106
107	return ret;
108}
109
110/*
111 * Define the register sets available on OpenRISC under Linux
112 */
113enum or1k_regset {
114	REGSET_GENERAL,
115};
116
117static const struct user_regset or1k_regsets[] = {
118	[REGSET_GENERAL] = {
119			    .core_note_type = NT_PRSTATUS,
120			    .n = ELF_NGREG,
121			    .size = sizeof(long),
122			    .align = sizeof(long),
123			    .get = genregs_get,
124			    .set = genregs_set,
125			    },
126};
127
128static const struct user_regset_view user_or1k_native_view = {
129	.name = "or1k",
130	.e_machine = EM_OPENRISC,
131	.regsets = or1k_regsets,
132	.n = ARRAY_SIZE(or1k_regsets),
133};
134
135const struct user_regset_view *task_user_regset_view(struct task_struct *task)
136{
137	return &user_or1k_native_view;
138}
139
140/*
141 * does not yet catch signals sent when the child dies.
142 * in exit.c or in signal.c.
143 */
144
145
146/*
147 * Called by kernel/ptrace.c when detaching..
148 *
149 * Make sure the single step bit is not set.
150 */
151void ptrace_disable(struct task_struct *child)
152{
153	pr_debug("ptrace_disable(): TODO\n");
154
155	user_disable_single_step(child);
156	clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
157}
158
159long arch_ptrace(struct task_struct *child, long request, unsigned long addr,
160		 unsigned long data)
161{
162	int ret;
163
164	switch (request) {
165	default:
166		ret = ptrace_request(child, request, addr, data);
167		break;
168	}
169
170	return ret;
171}
172
173/*
174 * Notification of system call entry/exit
175 * - triggered by current->work.syscall_trace
176 */
177asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
178{
179	long ret = 0;
180
181	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
182	    tracehook_report_syscall_entry(regs))
183		/*
184		 * Tracing decided this syscall should not happen.
185		 * We'll return a bogus call number to get an ENOSYS
186		 * error, but leave the original number in <something>.
187		 */
188		ret = -1L;
189
190	audit_syscall_entry(regs->gpr[11], regs->gpr[3], regs->gpr[4],
191			    regs->gpr[5], regs->gpr[6]);
192
193	return ret ? : regs->gpr[11];
194}
195
196asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
197{
198	int step;
199
200	audit_syscall_exit(regs);
201
202	step = test_thread_flag(TIF_SINGLESTEP);
203	if (step || test_thread_flag(TIF_SYSCALL_TRACE))
204		tracehook_report_syscall_exit(regs, step);
205}
206