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 #include <linux/tracehook.h>
37
38 #include <linux/errno.h>
39 #include <asm/processor.h>
40 #include <linux/uaccess.h>
41 #include <asm/asm-offsets.h>
42 #include <asm/cacheflush.h>
43 #include <asm/syscall.h>
44 #include <linux/io.h>
45
46 /* Returns the address where the register at REG_OFFS in P is stashed away. */
47 static microblaze_reg_t *reg_save_addr(unsigned reg_offs,
48 struct task_struct *t)
49 {
50 struct pt_regs *regs;
51
52 /*
53 * Three basic cases:
54 *
55 * (1) A register normally saved before calling the scheduler, is
56 * available in the kernel entry pt_regs structure at the top
57 * of the kernel stack. The kernel trap/irq exit path takes
58 * care to save/restore almost all registers for ptrace'd
59 * processes.
60 *
61 * (2) A call-clobbered register, where the process P entered the
62 * kernel via [syscall] trap, is not stored anywhere; that's
63 * OK, because such registers are not expected to be preserved
64 * when the trap returns anyway (so we don't actually bother to
65 * test for this case).
66 *
67 * (3) A few registers not used at all by the kernel, and so
68 * normally never saved except by context-switches, are in the
69 * context switch state.
70 */
71
72 /* Register saved during kernel entry (or not available). */
73 regs = task_pt_regs(t);
74
75 return (microblaze_reg_t *)((char *)regs + reg_offs);
76 }
77
78 long arch_ptrace(struct task_struct *child, long request,
79 unsigned long addr, unsigned long data)
80 {
81 int rval;
82 unsigned long val = 0;
83
84 switch (request) {
85 /* Read/write the word at location ADDR in the registers. */
86 case PTRACE_PEEKUSR:
87 case PTRACE_POKEUSR:
88 pr_debug("PEEKUSR/POKEUSR : 0x%08lx\n", addr);
89 rval = 0;
90 if (addr >= PT_SIZE && request == PTRACE_PEEKUSR) {
91 /*
92 * Special requests that don't actually correspond
93 * to offsets in struct pt_regs.
94 */
95 if (addr == PT_TEXT_ADDR) {
96 val = child->mm->start_code;
97 } else if (addr == PT_DATA_ADDR) {
98 val = child->mm->start_data;
99 } else if (addr == PT_TEXT_LEN) {
100 val = child->mm->end_code
101 - child->mm->start_code;
102 } else {
103 rval = -EIO;
104 }
105 } else if (addr < PT_SIZE && (addr & 0x3) == 0) {
106 microblaze_reg_t *reg_addr = reg_save_addr(addr, child);
107 if (request == PTRACE_PEEKUSR)
108 val = *reg_addr;
109 else {
110 #if 1
111 *reg_addr = data;
112 #else
113 /* MS potential problem on WB system
114 * Be aware that reg_addr is virtual address
115 * virt_to_phys conversion is necessary.
116 * This could be sensible solution.
117 */
118 u32 paddr = virt_to_phys((u32)reg_addr);
119 invalidate_icache_range(paddr, paddr + 4);
120 *reg_addr = data;
121 flush_dcache_range(paddr, paddr + 4);
122 #endif
123 }
124 } else
125 rval = -EIO;
126
127 if (rval == 0 && request == PTRACE_PEEKUSR)
128 rval = put_user(val, (unsigned long __user *)data);
129 break;
130 default:
131 rval = ptrace_request(child, request, addr, data);
132 }
133 return rval;
134 }
135
136 asmlinkage unsigned long do_syscall_trace_enter(struct pt_regs *regs)
137 {
138 unsigned long ret = 0;
139
140 secure_computing_strict(regs->r12);
141
142 if (test_thread_flag(TIF_SYSCALL_TRACE) &&
143 tracehook_report_syscall_entry(regs))
144 /*
145 * Tracing decided this syscall should not happen.
146 * We'll return a bogus call number to get an ENOSYS
147 * error, but leave the original number in regs->regs[0].
148 */
149 ret = -1L;
150
151 audit_syscall_entry(regs->r12, regs->r5, regs->r6, regs->r7, regs->r8);
152
153 return ret ?: regs->r12;
154 }
155
156 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
157 {
158 int step;
159
160 audit_syscall_exit(regs);
161
162 step = test_thread_flag(TIF_SINGLESTEP);
163 if (step || test_thread_flag(TIF_SYSCALL_TRACE))
164 tracehook_report_syscall_exit(regs, step);
165 }
166
167 void ptrace_disable(struct task_struct *child)
168 {
169 /* nothing to do */
170 }