1/*
2 * `ptrace' system call
3 *
4 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
5 * Copyright (C) 2007-2009 PetaLogix
6 * Copyright (C) 2004-2007 John Williams <john.williams@petalogix.com>
7 *
8 * derived from arch/v850/kernel/ptrace.c
9 *
10 * Copyright (C) 2002,03 NEC Electronics Corporation
11 * Copyright (C) 2002,03 Miles Bader <miles@gnu.org>
12 *
13 * Derived from arch/mips/kernel/ptrace.c:
14 *
15 * Copyright (C) 1992 Ross Biro
16 * Copyright (C) Linus Torvalds
17 * Copyright (C) 1994, 95, 96, 97, 98, 2000 Ralf Baechle
18 * Copyright (C) 1996 David S. Miller
19 * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
20 * Copyright (C) 1999 MIPS Technologies, Inc.
21 *
22 * This file is subject to the terms and conditions of the GNU General
23 * Public License. See the file COPYING in the main directory of this
24 * archive for more details.
25 */
26
27#include <linux/kernel.h>
28#include <linux/mm.h>
29#include <linux/sched.h>
30#include <linux/sched/task_stack.h>
31#include <linux/ptrace.h>
32#include <linux/signal.h>
33#include <linux/elf.h>
34#include <linux/audit.h>
35#include <linux/seccomp.h>
36
37#include <linux/errno.h>
38#include <asm/processor.h>
39#include <linux/uaccess.h>
40#include <asm/asm-offsets.h>
41#include <asm/cacheflush.h>
42#include <asm/syscall.h>
43#include <linux/io.h>
44
45/* Returns the address where the register at REG_OFFS in P is stashed away. */
46static microblaze_reg_t *reg_save_addr(unsigned reg_offs,
47					struct task_struct *t)
48{
49	struct pt_regs *regs;
50
51	/*
52	 * Three basic cases:
53	 *
54	 * (1)	A register normally saved before calling the scheduler, is
55	 *	available in the kernel entry pt_regs structure at the top
56	 *	of the kernel stack. The kernel trap/irq exit path takes
57	 *	care to save/restore almost all registers for ptrace'd
58	 *	processes.
59	 *
60	 * (2)	A call-clobbered register, where the process P entered the
61	 *	kernel via [syscall] trap, is not stored anywhere; that's
62	 *	OK, because such registers are not expected to be preserved
63	 *	when the trap returns anyway (so we don't actually bother to
64	 *	test for this case).
65	 *
66	 * (3)	A few registers not used at all by the kernel, and so
67	 *	normally never saved except by context-switches, are in the
68	 *	context switch state.
69	 */
70
71	/* Register saved during kernel entry (or not available). */
72	regs = task_pt_regs(t);
73
74	return (microblaze_reg_t *)((char *)regs + reg_offs);
75}
76
77long arch_ptrace(struct task_struct *child, long request,
78		 unsigned long addr, unsigned long data)
79{
80	int rval;
81	unsigned long val = 0;
82
83	switch (request) {
84	/* Read/write the word at location ADDR in the registers. */
85	case PTRACE_PEEKUSR:
86	case PTRACE_POKEUSR:
87		pr_debug("PEEKUSR/POKEUSR : 0x%08lx\n", addr);
88		rval = 0;
89		if (addr >= PT_SIZE && request == PTRACE_PEEKUSR) {
90			/*
91			 * Special requests that don't actually correspond
92			 * to offsets in struct pt_regs.
93			 */
94			if (addr == PT_TEXT_ADDR) {
95				val = child->mm->start_code;
96			} else if (addr == PT_DATA_ADDR) {
97				val = child->mm->start_data;
98			} else if (addr == PT_TEXT_LEN) {
99				val = child->mm->end_code
100					- child->mm->start_code;
101			} else {
102				rval = -EIO;
103			}
104		} else if (addr < PT_SIZE && (addr & 0x3) == 0) {
105			microblaze_reg_t *reg_addr = reg_save_addr(addr, child);
106			if (request == PTRACE_PEEKUSR)
107				val = *reg_addr;
108			else {
109#if 1
110				*reg_addr = data;
111#else
112				/* MS potential problem on WB system
113				 * Be aware that reg_addr is virtual address
114				 * virt_to_phys conversion is necessary.
115				 * This could be sensible solution.
116				 */
117				u32 paddr = virt_to_phys((u32)reg_addr);
118				invalidate_icache_range(paddr, paddr + 4);
119				*reg_addr = data;
120				flush_dcache_range(paddr, paddr + 4);
121#endif
122			}
123		} else
124			rval = -EIO;
125
126		if (rval == 0 && request == PTRACE_PEEKUSR)
127			rval = put_user(val, (unsigned long __user *)data);
128		break;
129	default:
130		rval = ptrace_request(child, request, addr, data);
131	}
132	return rval;
133}
134
135asmlinkage unsigned long do_syscall_trace_enter(struct pt_regs *regs)
136{
137	unsigned long ret = 0;
138
139	secure_computing_strict(regs->r12);
140
141	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
142	    ptrace_report_syscall_entry(regs))
143		/*
144		 * Tracing decided this syscall should not happen.
145		 * We'll return a bogus call number to get an ENOSYS
146		 * error, but leave the original number in regs->regs[0].
147		 */
148		ret = -1L;
149
150	audit_syscall_entry(regs->r12, regs->r5, regs->r6, regs->r7, regs->r8);
151
152	return ret ?: regs->r12;
153}
154
155asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
156{
157	int step;
158
159	audit_syscall_exit(regs);
160
161	step = test_thread_flag(TIF_SINGLESTEP);
162	if (step || test_thread_flag(TIF_SYSCALL_TRACE))
163		ptrace_report_syscall_exit(regs, step);
164}
165
166void ptrace_disable(struct task_struct *child)
167{
168	/* nothing to do */
169}
170