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. */
46 static 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
77 long 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
135 asmlinkage 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
155 asmlinkage 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
166 void ptrace_disable(struct task_struct *child)
167 {
168 /* nothing to do */
169 }
170
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