1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
|
/*
* Userspace Probes (UProbes)
* arch/s390/uprobes/uprobes_s390.c
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright (C) IBM Corporation, 2006
*/
/*
* In versions of uprobes built in the SystemTap runtime, this file
* is #included at the end of uprobes.c.
*/
#include <linux/uaccess.h>
/* adapted from s390/kernel/kprobes.c is_prohibited_opcode() */
/* TODO More instructions?? Should floating point inst be added?? */
static int prohibited_opcode(uprobe_opcode_t *instruction)
{
switch (*(__u8 *) instruction) {
case 0x0c: /* bassm */
case 0x0b: /* bsm */
case 0x83: /* diag */
case 0x44: /* ex */
return -EINVAL;
}
switch (*(__u16 *) instruction) {
case 0x0101: /* pr */
case 0xb25a: /* bsa */
case 0xb240: /* bakr */
case 0xb258: /* bsg */
case 0xb218: /* pc */
case 0xb228: /* pt */
return -EINVAL;
}
return 0;
}
static
int arch_validate_probed_insn(struct uprobe_probept *ppt,
struct task_struct *tsk)
{
if (ppt->vaddr & 0x01) {
printk("Attempt to register uprobe at an unaligned address\n");
return -EPERM;
}
/* Make sure the probe isn't going on a difficult instruction */
if (prohibited_opcode((uprobe_opcode_t *) ppt->insn))
return -EPERM;
return 0;
}
/*
* Get an instruction slot from the process's SSOL area, containing the
* instruction at ppt's probepoint. Point the psw.addr at that slot, in
* preparation for single-stepping out of line.
*/
static
void uprobe_pre_ssout(struct uprobe_task *utask, struct uprobe_probept *ppt,
struct pt_regs *regs)
{
struct uprobe_ssol_slot *slot;
slot = uprobe_get_insn_slot(ppt);
if (!slot) {
utask->doomed = 1;
return;
}
regs->psw.addr = (long)slot->insn;
utask->singlestep_addr = regs->psw.addr;
}
static
void uprobe_post_ssout(struct uprobe_task *utask, struct uprobe_probept *ppt,
struct pt_regs *regs)
{
int ilen, fixup, reg;
unsigned long copy_ins_addr = utask->singlestep_addr;
unsigned long orig_ins_addr = ppt->vaddr;
up_read(&ppt->slot->rwsem);
/* default fixup method */
fixup = FIXUP_PSW_NORMAL;;
/* get r1 operand */
reg = (*ppt->insn & 0xf0) >> 4;
/* save the instruction length (pop 5-5) in bytes */
switch (*(__u8 *) (ppt->insn) >> 6) {
case 0:
ilen = 2;
break;
case 1:
case 2:
ilen = 4;
break;
case 3:
ilen = 6;
break;
default:
ilen = 0;
BUG();
}
switch (*(__u8 *) ppt->insn) {
case 0x05: /* balr */
case 0x0d: /* basr */
fixup = FIXUP_RETURN_REGISTER;
/* if r2 = 0, no branch will be taken */
if ((*ppt->insn & 0x0f) == 0)
fixup |= FIXUP_BRANCH_NOT_TAKEN;
break;
case 0x06: /* bctr */
case 0x07: /* bcr */
fixup = FIXUP_BRANCH_NOT_TAKEN;
break;
case 0x45: /* bal */
case 0x4d: /* bas */
fixup = FIXUP_RETURN_REGISTER;
break;
case 0x47: /* bc */
case 0x46: /* bct */
case 0x86: /* bxh */
case 0x87: /* bxle */
fixup = FIXUP_BRANCH_NOT_TAKEN;
break;
case 0x82: /* lpsw */
fixup = FIXUP_NOT_REQUIRED;
break;
case 0xb2: /* lpswe */
if (*(((__u8 *) ppt->insn) + 1) == 0xb2) {
fixup = FIXUP_NOT_REQUIRED;
}
break;
case 0xa7: /* bras */
if ((*ppt->insn & 0x0f) == 0x05) {
fixup |= FIXUP_RETURN_REGISTER;
}
break;
case 0xc0:
if ((*ppt->insn & 0x0f) == 0x00 /* larl */
|| (*ppt->insn & 0x0f) == 0x05) /* brasl */
fixup |= FIXUP_RETURN_REGISTER;
break;
case 0xeb:
if (*(((__u8 *) ppt->insn) + 5 ) == 0x44 || /* bxhg */
*(((__u8 *) ppt->insn) + 5) == 0x45) {/* bxleg */
fixup = FIXUP_BRANCH_NOT_TAKEN;
}
break;
case 0xe3: /* bctg */
if (*(((__u8 *) ppt->insn) + 5) == 0x46) {
fixup = FIXUP_BRANCH_NOT_TAKEN;
}
break;
}
/* do the fixup and adjust psw as needed */
regs->psw.addr &= PSW_ADDR_INSN;
if (fixup & FIXUP_PSW_NORMAL)
regs->psw.addr = orig_ins_addr + regs->psw.addr -
copy_ins_addr;
if (fixup & FIXUP_BRANCH_NOT_TAKEN)
if (regs->psw.addr - copy_ins_addr == ilen)
regs->psw.addr = orig_ins_addr + ilen;
if (fixup & FIXUP_RETURN_REGISTER)
regs->gprs[reg] = (orig_ins_addr + (regs->gprs[reg] -
copy_ins_addr)) | PSW_ADDR_AMODE;
regs->psw.addr |= PSW_ADDR_AMODE;
}
/*
* Replace the return address with the trampoline address. Returns
* the original return address.
*/
static
unsigned long arch_hijack_uret_addr(unsigned long trampoline_address,
struct pt_regs *regs, struct uprobe_task *utask)
{
unsigned long orig_ret_addr;
#ifdef CONFIG_COMPAT
if (test_tsk_thread_flag(utask->tsk, TIF_31BIT))
orig_ret_addr = regs->gprs[14]&0x7FFFFFFFUL;
else
#endif
orig_ret_addr = regs->gprs[14];
regs->gprs[14] = trampoline_address;
return orig_ret_addr;
}
|
