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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Kernel Probes (KProbes)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 *
18 * Copyright (C) IBM Corporation, 2002, 2004
19 *
20 * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
21 * Probes initial implementation ( includes contributions from
22 * Rusty Russell).
23 * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
24 * interface to access function arguments.
Masami Hiramatsud6be29b2008-01-30 13:31:21 +010025 * 2004-Oct Jim Keniston <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
26 * <prasanna@in.ibm.com> adapted for x86_64 from i386.
Linus Torvalds1da177e2005-04-16 15:20:36 -070027 * 2005-Mar Roland McGrath <roland@redhat.com>
28 * Fixed to handle %rip-relative addressing mode correctly.
Masami Hiramatsud6be29b2008-01-30 13:31:21 +010029 * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston
30 * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
31 * <prasanna@in.ibm.com> added function-return probes.
32 * 2005-May Rusty Lynch <rusty.lynch@intel.com>
Masami Hiramatsu3f33ab12012-03-05 22:32:22 +090033 * Added function return probes functionality
Masami Hiramatsud6be29b2008-01-30 13:31:21 +010034 * 2006-Feb Masami Hiramatsu <hiramatu@sdl.hitachi.co.jp> added
Masami Hiramatsu3f33ab12012-03-05 22:32:22 +090035 * kprobe-booster and kretprobe-booster for i386.
Masami Hiramatsuda07ab02008-01-30 13:31:21 +010036 * 2007-Dec Masami Hiramatsu <mhiramat@redhat.com> added kprobe-booster
Masami Hiramatsu3f33ab12012-03-05 22:32:22 +090037 * and kretprobe-booster for x86-64
Masami Hiramatsud6be29b2008-01-30 13:31:21 +010038 * 2007-Dec Masami Hiramatsu <mhiramat@redhat.com>, Arjan van de Ven
Masami Hiramatsu3f33ab12012-03-05 22:32:22 +090039 * <arjan@infradead.org> and Jim Keniston <jkenisto@us.ibm.com>
40 * unified x86 kprobes code.
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070042#include <linux/kprobes.h>
43#include <linux/ptrace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070044#include <linux/string.h>
45#include <linux/slab.h>
Quentin Barnesb506a9d2008-01-30 13:32:32 +010046#include <linux/hardirq.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070047#include <linux/preempt.h>
Prasanna S Panchamukhic28f8962006-03-26 01:38:23 -080048#include <linux/module.h>
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -070049#include <linux/kdebug.h>
Masami Hiramatsub46b3d72009-08-13 16:34:28 -040050#include <linux/kallsyms.h>
Masami Hiramatsuc0f7ac32010-02-25 08:34:46 -050051#include <linux/ftrace.h>
Ananth N Mavinakayanahalli9ec4b1f2005-06-27 15:17:01 -070052
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +010053#include <asm/cacheflush.h>
54#include <asm/desc.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070055#include <asm/pgtable.h>
Prasanna S Panchamukhic28f8962006-03-26 01:38:23 -080056#include <asm/uaccess.h>
Andi Kleen19d36cc2007-07-22 11:12:31 +020057#include <asm/alternative.h>
Masami Hiramatsub46b3d72009-08-13 16:34:28 -040058#include <asm/insn.h>
K.Prasad62edab92009-06-01 23:47:06 +053059#include <asm/debugreg.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070060
Masami Hiramatsuf6841992012-09-28 17:15:22 +090061#include "common.h"
Masami Hiramatsu3f33ab12012-03-05 22:32:22 +090062
Linus Torvalds1da177e2005-04-16 15:20:36 -070063void jprobe_return_end(void);
64
Ananth N Mavinakayanahallie7a510f2005-11-07 01:00:12 -080065DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
66DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
Linus Torvalds1da177e2005-04-16 15:20:36 -070067
H. Peter Anvin98272ed2009-10-12 14:14:10 -070068#define stack_addr(regs) ((unsigned long *)kernel_stack_pointer(regs))
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +010069
70#define W(row, b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, ba, bb, bc, bd, be, bf)\
71 (((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \
72 (b4##UL << 0x4)|(b5##UL << 0x5)|(b6##UL << 0x6)|(b7##UL << 0x7) | \
73 (b8##UL << 0x8)|(b9##UL << 0x9)|(ba##UL << 0xa)|(bb##UL << 0xb) | \
74 (bc##UL << 0xc)|(bd##UL << 0xd)|(be##UL << 0xe)|(bf##UL << 0xf)) \
75 << (row % 32))
76 /*
77 * Undefined/reserved opcodes, conditional jump, Opcode Extension
78 * Groups, and some special opcodes can not boost.
Linus Torvalds7115e3f2011-10-26 17:03:38 +020079 * This is non-const and volatile to keep gcc from statically
80 * optimizing it out, as variable_test_bit makes gcc think only
Masami Hiramatsuf6841992012-09-28 17:15:22 +090081 * *(unsigned long*) is used.
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +010082 */
Linus Torvalds7115e3f2011-10-26 17:03:38 +020083static volatile u32 twobyte_is_boostable[256 / 32] = {
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +010084 /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
85 /* ---------------------------------------------- */
86 W(0x00, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0) | /* 00 */
87 W(0x10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 10 */
88 W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 20 */
89 W(0x30, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 30 */
90 W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 40 */
91 W(0x50, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 50 */
92 W(0x60, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1) | /* 60 */
93 W(0x70, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1) , /* 70 */
94 W(0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 80 */
95 W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 90 */
96 W(0xa0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1) | /* a0 */
97 W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1) , /* b0 */
98 W(0xc0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1) | /* c0 */
99 W(0xd0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1) , /* d0 */
100 W(0xe0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1) | /* e0 */
101 W(0xf0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0, 1, 1, 1, 0) /* f0 */
102 /* ----------------------------------------------- */
103 /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
104};
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100105#undef W
106
Masami Hiramatsuf438d912007-10-16 01:27:49 -0700107struct kretprobe_blackpoint kretprobe_blacklist[] = {
108 {"__switch_to", }, /* This function switches only current task, but
109 doesn't switch kernel stack.*/
110 {NULL, NULL} /* Terminator */
111};
Masami Hiramatsu3f33ab12012-03-05 22:32:22 +0900112
Masami Hiramatsuf438d912007-10-16 01:27:49 -0700113const int kretprobe_blacklist_size = ARRAY_SIZE(kretprobe_blacklist);
114
Masami Hiramatsuc0f7ac32010-02-25 08:34:46 -0500115static void __kprobes __synthesize_relative_insn(void *from, void *to, u8 op)
Masami Hiramatsuaa470142008-01-30 13:31:21 +0100116{
Masami Hiramatsuc0f7ac32010-02-25 08:34:46 -0500117 struct __arch_relative_insn {
118 u8 op;
Masami Hiramatsuaa470142008-01-30 13:31:21 +0100119 s32 raddr;
Masami Hiramatsuf6841992012-09-28 17:15:22 +0900120 } __packed *insn;
Masami Hiramatsuc0f7ac32010-02-25 08:34:46 -0500121
122 insn = (struct __arch_relative_insn *)from;
123 insn->raddr = (s32)((long)(to) - ((long)(from) + 5));
124 insn->op = op;
125}
126
127/* Insert a jump instruction at address 'from', which jumps to address 'to'.*/
Masami Hiramatsu3f33ab12012-03-05 22:32:22 +0900128void __kprobes synthesize_reljump(void *from, void *to)
Masami Hiramatsuc0f7ac32010-02-25 08:34:46 -0500129{
130 __synthesize_relative_insn(from, to, RELATIVEJUMP_OPCODE);
Masami Hiramatsuaa470142008-01-30 13:31:21 +0100131}
132
Masami Hiramatsu3f33ab12012-03-05 22:32:22 +0900133/* Insert a call instruction at address 'from', which calls address 'to'.*/
134void __kprobes synthesize_relcall(void *from, void *to)
135{
136 __synthesize_relative_insn(from, to, RELATIVECALL_OPCODE);
137}
138
Masami Hiramatsuaa470142008-01-30 13:31:21 +0100139/*
Masami Hiramatsu567a9fd2010-06-29 14:53:50 +0900140 * Skip the prefixes of the instruction.
Harvey Harrison99309272008-01-30 13:32:14 +0100141 */
Masami Hiramatsu567a9fd2010-06-29 14:53:50 +0900142static kprobe_opcode_t *__kprobes skip_prefixes(kprobe_opcode_t *insn)
Harvey Harrison99309272008-01-30 13:32:14 +0100143{
Masami Hiramatsu567a9fd2010-06-29 14:53:50 +0900144 insn_attr_t attr;
145
146 attr = inat_get_opcode_attribute((insn_byte_t)*insn);
147 while (inat_is_legacy_prefix(attr)) {
148 insn++;
149 attr = inat_get_opcode_attribute((insn_byte_t)*insn);
150 }
Harvey Harrison99309272008-01-30 13:32:14 +0100151#ifdef CONFIG_X86_64
Masami Hiramatsu567a9fd2010-06-29 14:53:50 +0900152 if (inat_is_rex_prefix(attr))
153 insn++;
Harvey Harrison99309272008-01-30 13:32:14 +0100154#endif
Masami Hiramatsu567a9fd2010-06-29 14:53:50 +0900155 return insn;
Harvey Harrison99309272008-01-30 13:32:14 +0100156}
157
158/*
Masami Hiramatsud6be29b2008-01-30 13:31:21 +0100159 * Returns non-zero if opcode is boostable.
160 * RIP relative instructions are adjusted at copying time in 64 bits mode
Masami Hiramatsuaa470142008-01-30 13:31:21 +0100161 */
Masami Hiramatsu3f33ab12012-03-05 22:32:22 +0900162int __kprobes can_boost(kprobe_opcode_t *opcodes)
Masami Hiramatsuaa470142008-01-30 13:31:21 +0100163{
Masami Hiramatsuaa470142008-01-30 13:31:21 +0100164 kprobe_opcode_t opcode;
165 kprobe_opcode_t *orig_opcodes = opcodes;
166
Jaswinder Singh Rajputcde5edb2009-03-18 17:37:45 +0530167 if (search_exception_tables((unsigned long)opcodes))
Masami Hiramatsu30390882009-03-16 18:57:22 -0400168 return 0; /* Page fault may occur on this address. */
169
Masami Hiramatsuaa470142008-01-30 13:31:21 +0100170retry:
171 if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
172 return 0;
173 opcode = *(opcodes++);
174
175 /* 2nd-byte opcode */
176 if (opcode == 0x0f) {
177 if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
178 return 0;
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100179 return test_bit(*opcodes,
180 (unsigned long *)twobyte_is_boostable);
Masami Hiramatsuaa470142008-01-30 13:31:21 +0100181 }
182
183 switch (opcode & 0xf0) {
Masami Hiramatsud6be29b2008-01-30 13:31:21 +0100184#ifdef CONFIG_X86_64
Masami Hiramatsuaa470142008-01-30 13:31:21 +0100185 case 0x40:
186 goto retry; /* REX prefix is boostable */
Masami Hiramatsud6be29b2008-01-30 13:31:21 +0100187#endif
Masami Hiramatsuaa470142008-01-30 13:31:21 +0100188 case 0x60:
189 if (0x63 < opcode && opcode < 0x67)
190 goto retry; /* prefixes */
191 /* can't boost Address-size override and bound */
192 return (opcode != 0x62 && opcode != 0x67);
193 case 0x70:
194 return 0; /* can't boost conditional jump */
195 case 0xc0:
196 /* can't boost software-interruptions */
197 return (0xc1 < opcode && opcode < 0xcc) || opcode == 0xcf;
198 case 0xd0:
199 /* can boost AA* and XLAT */
200 return (opcode == 0xd4 || opcode == 0xd5 || opcode == 0xd7);
201 case 0xe0:
202 /* can boost in/out and absolute jmps */
203 return ((opcode & 0x04) || opcode == 0xea);
204 case 0xf0:
205 if ((opcode & 0x0c) == 0 && opcode != 0xf1)
206 goto retry; /* lock/rep(ne) prefix */
207 /* clear and set flags are boostable */
208 return (opcode == 0xf5 || (0xf7 < opcode && opcode < 0xfe));
209 default:
210 /* segment override prefixes are boostable */
211 if (opcode == 0x26 || opcode == 0x36 || opcode == 0x3e)
212 goto retry; /* prefixes */
213 /* CS override prefix and call are not boostable */
214 return (opcode != 0x2e && opcode != 0x9a);
215 }
216}
217
Masami Hiramatsu3f33ab12012-03-05 22:32:22 +0900218static unsigned long
219__recover_probed_insn(kprobe_opcode_t *buf, unsigned long addr)
Masami Hiramatsub46b3d72009-08-13 16:34:28 -0400220{
221 struct kprobe *kp;
Masami Hiramatsu86b4ce32012-03-05 22:32:09 +0900222
Masami Hiramatsub46b3d72009-08-13 16:34:28 -0400223 kp = get_kprobe((void *)addr);
Masami Hiramatsu86b4ce32012-03-05 22:32:09 +0900224 /* There is no probe, return original address */
Masami Hiramatsub46b3d72009-08-13 16:34:28 -0400225 if (!kp)
Masami Hiramatsu86b4ce32012-03-05 22:32:09 +0900226 return addr;
Masami Hiramatsub46b3d72009-08-13 16:34:28 -0400227
228 /*
229 * Basically, kp->ainsn.insn has an original instruction.
230 * However, RIP-relative instruction can not do single-stepping
Masami Hiramatsuc0f7ac32010-02-25 08:34:46 -0500231 * at different place, __copy_instruction() tweaks the displacement of
Masami Hiramatsub46b3d72009-08-13 16:34:28 -0400232 * that instruction. In that case, we can't recover the instruction
233 * from the kp->ainsn.insn.
234 *
235 * On the other hand, kp->opcode has a copy of the first byte of
236 * the probed instruction, which is overwritten by int3. And
237 * the instruction at kp->addr is not modified by kprobes except
238 * for the first byte, we can recover the original instruction
239 * from it and kp->opcode.
240 */
241 memcpy(buf, kp->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
242 buf[0] = kp->opcode;
Masami Hiramatsu86b4ce32012-03-05 22:32:09 +0900243 return (unsigned long)buf;
244}
245
Masami Hiramatsu86b4ce32012-03-05 22:32:09 +0900246/*
247 * Recover the probed instruction at addr for further analysis.
248 * Caller must lock kprobes by kprobe_mutex, or disable preemption
249 * for preventing to release referencing kprobes.
250 */
Masami Hiramatsu3f33ab12012-03-05 22:32:22 +0900251unsigned long recover_probed_instruction(kprobe_opcode_t *buf, unsigned long addr)
Masami Hiramatsu86b4ce32012-03-05 22:32:09 +0900252{
253 unsigned long __addr;
254
255 __addr = __recover_optprobed_insn(buf, addr);
256 if (__addr != addr)
257 return __addr;
258
259 return __recover_probed_insn(buf, addr);
Masami Hiramatsub46b3d72009-08-13 16:34:28 -0400260}
261
Masami Hiramatsub46b3d72009-08-13 16:34:28 -0400262/* Check if paddr is at an instruction boundary */
263static int __kprobes can_probe(unsigned long paddr)
264{
Masami Hiramatsu86b4ce32012-03-05 22:32:09 +0900265 unsigned long addr, __addr, offset = 0;
Masami Hiramatsub46b3d72009-08-13 16:34:28 -0400266 struct insn insn;
267 kprobe_opcode_t buf[MAX_INSN_SIZE];
268
Namhyung Kim6abded72010-09-15 10:04:29 +0900269 if (!kallsyms_lookup_size_offset(paddr, NULL, &offset))
Masami Hiramatsub46b3d72009-08-13 16:34:28 -0400270 return 0;
271
272 /* Decode instructions */
273 addr = paddr - offset;
274 while (addr < paddr) {
Masami Hiramatsub46b3d72009-08-13 16:34:28 -0400275 /*
276 * Check if the instruction has been modified by another
277 * kprobe, in which case we replace the breakpoint by the
278 * original instruction in our buffer.
Masami Hiramatsu86b4ce32012-03-05 22:32:09 +0900279 * Also, jump optimization will change the breakpoint to
280 * relative-jump. Since the relative-jump itself is
281 * normally used, we just go through if there is no kprobe.
Masami Hiramatsub46b3d72009-08-13 16:34:28 -0400282 */
Masami Hiramatsu86b4ce32012-03-05 22:32:09 +0900283 __addr = recover_probed_instruction(buf, addr);
284 kernel_insn_init(&insn, (void *)__addr);
Masami Hiramatsub46b3d72009-08-13 16:34:28 -0400285 insn_get_length(&insn);
Masami Hiramatsu86b4ce32012-03-05 22:32:09 +0900286
287 /*
288 * Another debugging subsystem might insert this breakpoint.
289 * In that case, we can't recover it.
290 */
291 if (insn.opcode.bytes[0] == BREAKPOINT_INSTRUCTION)
292 return 0;
Masami Hiramatsub46b3d72009-08-13 16:34:28 -0400293 addr += insn.length;
294 }
295
296 return (addr == paddr);
297}
298
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299/*
Masami Hiramatsud6be29b2008-01-30 13:31:21 +0100300 * Returns non-zero if opcode modifies the interrupt flag.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301 */
Andrew Morton86454192007-11-26 20:42:19 +0100302static int __kprobes is_IF_modifier(kprobe_opcode_t *insn)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303{
Masami Hiramatsu567a9fd2010-06-29 14:53:50 +0900304 /* Skip prefixes */
305 insn = skip_prefixes(insn);
306
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 switch (*insn) {
308 case 0xfa: /* cli */
309 case 0xfb: /* sti */
310 case 0xcf: /* iret/iretd */
311 case 0x9d: /* popf/popfd */
312 return 1;
313 }
Harvey Harrison99309272008-01-30 13:32:14 +0100314
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315 return 0;
316}
317
318/*
Masami Hiramatsuc0f7ac32010-02-25 08:34:46 -0500319 * Copy an instruction and adjust the displacement if the instruction
320 * uses the %rip-relative addressing mode.
Masami Hiramatsuaa470142008-01-30 13:31:21 +0100321 * If it does, Return the address of the 32-bit displacement word.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322 * If not, return null.
Harvey Harrison31f80e42008-01-30 13:32:16 +0100323 * Only applicable to 64-bit x86.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324 */
Masami Hiramatsu3f33ab12012-03-05 22:32:22 +0900325int __kprobes __copy_instruction(u8 *dest, u8 *src)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326{
Masami Hiramatsu89ae4652009-08-13 16:34:36 -0400327 struct insn insn;
Masami Hiramatsuc0f7ac32010-02-25 08:34:46 -0500328 kprobe_opcode_t buf[MAX_INSN_SIZE];
Masami Hiramatsu86b4ce32012-03-05 22:32:09 +0900329
Masami Hiramatsu46484682012-03-05 22:32:16 +0900330 kernel_insn_init(&insn, (void *)recover_probed_instruction(buf, (unsigned long)src));
Masami Hiramatsuc0f7ac32010-02-25 08:34:46 -0500331 insn_get_length(&insn);
Masami Hiramatsu86b4ce32012-03-05 22:32:09 +0900332 /* Another subsystem puts a breakpoint, failed to recover */
Masami Hiramatsu46484682012-03-05 22:32:16 +0900333 if (insn.opcode.bytes[0] == BREAKPOINT_INSTRUCTION)
Masami Hiramatsu86b4ce32012-03-05 22:32:09 +0900334 return 0;
Masami Hiramatsuc0f7ac32010-02-25 08:34:46 -0500335 memcpy(dest, insn.kaddr, insn.length);
336
337#ifdef CONFIG_X86_64
Masami Hiramatsu89ae4652009-08-13 16:34:36 -0400338 if (insn_rip_relative(&insn)) {
339 s64 newdisp;
340 u8 *disp;
Masami Hiramatsuc0f7ac32010-02-25 08:34:46 -0500341 kernel_insn_init(&insn, dest);
Masami Hiramatsu89ae4652009-08-13 16:34:36 -0400342 insn_get_displacement(&insn);
343 /*
344 * The copied instruction uses the %rip-relative addressing
345 * mode. Adjust the displacement for the difference between
346 * the original location of this instruction and the location
347 * of the copy that will actually be run. The tricky bit here
348 * is making sure that the sign extension happens correctly in
349 * this calculation, since we need a signed 32-bit result to
350 * be sign-extended to 64 bits when it's added to the %rip
351 * value and yield the same 64-bit result that the sign-
352 * extension of the original signed 32-bit displacement would
353 * have given.
354 */
Masami Hiramatsu46484682012-03-05 22:32:16 +0900355 newdisp = (u8 *) src + (s64) insn.displacement.value - (u8 *) dest;
Masami Hiramatsu89ae4652009-08-13 16:34:36 -0400356 BUG_ON((s64) (s32) newdisp != newdisp); /* Sanity check. */
Masami Hiramatsuc0f7ac32010-02-25 08:34:46 -0500357 disp = (u8 *) dest + insn_offset_displacement(&insn);
Masami Hiramatsu89ae4652009-08-13 16:34:36 -0400358 *(s32 *) disp = (s32) newdisp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359 }
Masami Hiramatsud6be29b2008-01-30 13:31:21 +0100360#endif
Masami Hiramatsuc0f7ac32010-02-25 08:34:46 -0500361 return insn.length;
Harvey Harrison31f80e42008-01-30 13:32:16 +0100362}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363
Keshavamurthy Anil Sf709b122006-01-09 20:52:44 -0800364static void __kprobes arch_copy_kprobe(struct kprobe *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365{
Masami Hiramatsu46484682012-03-05 22:32:16 +0900366 /* Copy an instruction with recovering if other optprobe modifies it.*/
367 __copy_instruction(p->ainsn.insn, p->addr);
Harvey Harrison31f80e42008-01-30 13:32:16 +0100368
Masami Hiramatsu46484682012-03-05 22:32:16 +0900369 /*
370 * __copy_instruction can modify the displacement of the instruction,
371 * but it doesn't affect boostable check.
372 */
373 if (can_boost(p->ainsn.insn))
Masami Hiramatsuaa470142008-01-30 13:31:21 +0100374 p->ainsn.boostable = 0;
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100375 else
Masami Hiramatsuaa470142008-01-30 13:31:21 +0100376 p->ainsn.boostable = -1;
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100377
Masami Hiramatsu46484682012-03-05 22:32:16 +0900378 /* Also, displacement change doesn't affect the first byte */
379 p->opcode = p->ainsn.insn[0];
Rusty Lynch7e1048b2005-06-23 00:09:25 -0700380}
381
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100382int __kprobes arch_prepare_kprobe(struct kprobe *p)
383{
Masami Hiramatsu4554dbc2010-02-02 16:49:18 -0500384 if (alternatives_text_reserved(p->addr, p->addr))
385 return -EINVAL;
386
Masami Hiramatsub46b3d72009-08-13 16:34:28 -0400387 if (!can_probe((unsigned long)p->addr))
388 return -EILSEQ;
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100389 /* insn: must be on special executable page on x86. */
390 p->ainsn.insn = get_insn_slot();
391 if (!p->ainsn.insn)
392 return -ENOMEM;
393 arch_copy_kprobe(p);
394 return 0;
395}
396
Prasanna S Panchamukhi0f2fbdc2005-09-06 15:19:28 -0700397void __kprobes arch_arm_kprobe(struct kprobe *p)
Rusty Lynch7e1048b2005-06-23 00:09:25 -0700398{
Andi Kleen19d36cc2007-07-22 11:12:31 +0200399 text_poke(p->addr, ((unsigned char []){BREAKPOINT_INSTRUCTION}), 1);
Rusty Lynch7e1048b2005-06-23 00:09:25 -0700400}
401
Prasanna S Panchamukhi0f2fbdc2005-09-06 15:19:28 -0700402void __kprobes arch_disarm_kprobe(struct kprobe *p)
Rusty Lynch7e1048b2005-06-23 00:09:25 -0700403{
Andi Kleen19d36cc2007-07-22 11:12:31 +0200404 text_poke(p->addr, &p->opcode, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405}
406
Ananth N Mavinakayanahalli0498b632006-01-09 20:52:46 -0800407void __kprobes arch_remove_kprobe(struct kprobe *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408{
Masami Hiramatsu12941562009-01-06 14:41:50 -0800409 if (p->ainsn.insn) {
410 free_insn_slot(p->ainsn.insn, (p->ainsn.boostable == 1));
411 p->ainsn.insn = NULL;
412 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413}
414
Prasanna S Panchamukhi3b602112006-04-18 22:22:00 -0700415static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
Prasanna S Panchamukhiaa3d7e32005-06-23 00:09:37 -0700416{
Ananth N Mavinakayanahallie7a510f2005-11-07 01:00:12 -0800417 kcb->prev_kprobe.kp = kprobe_running();
418 kcb->prev_kprobe.status = kcb->kprobe_status;
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100419 kcb->prev_kprobe.old_flags = kcb->kprobe_old_flags;
420 kcb->prev_kprobe.saved_flags = kcb->kprobe_saved_flags;
Prasanna S Panchamukhiaa3d7e32005-06-23 00:09:37 -0700421}
422
Prasanna S Panchamukhi3b602112006-04-18 22:22:00 -0700423static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
Prasanna S Panchamukhiaa3d7e32005-06-23 00:09:37 -0700424{
Christoph Lameterb76834b2010-12-06 11:16:25 -0600425 __this_cpu_write(current_kprobe, kcb->prev_kprobe.kp);
Ananth N Mavinakayanahallie7a510f2005-11-07 01:00:12 -0800426 kcb->kprobe_status = kcb->prev_kprobe.status;
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100427 kcb->kprobe_old_flags = kcb->prev_kprobe.old_flags;
428 kcb->kprobe_saved_flags = kcb->prev_kprobe.saved_flags;
Prasanna S Panchamukhiaa3d7e32005-06-23 00:09:37 -0700429}
430
Prasanna S Panchamukhi3b602112006-04-18 22:22:00 -0700431static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
Ananth N Mavinakayanahallie7a510f2005-11-07 01:00:12 -0800432 struct kprobe_ctlblk *kcb)
Prasanna S Panchamukhiaa3d7e32005-06-23 00:09:37 -0700433{
Christoph Lameterb76834b2010-12-06 11:16:25 -0600434 __this_cpu_write(current_kprobe, p);
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100435 kcb->kprobe_saved_flags = kcb->kprobe_old_flags
Glauber de Oliveira Costa053de042008-01-30 13:31:27 +0100436 = (regs->flags & (X86_EFLAGS_TF | X86_EFLAGS_IF));
Prasanna S Panchamukhiaa3d7e32005-06-23 00:09:37 -0700437 if (is_IF_modifier(p->ainsn.insn))
Glauber de Oliveira Costa053de042008-01-30 13:31:27 +0100438 kcb->kprobe_saved_flags &= ~X86_EFLAGS_IF;
Prasanna S Panchamukhiaa3d7e32005-06-23 00:09:37 -0700439}
440
Harvey Harrisone7b5e112008-01-30 13:31:43 +0100441static void __kprobes clear_btf(void)
Roland McGrath1ecc7982008-01-30 13:30:54 +0100442{
Peter Zijlstraea8e61b2010-03-25 14:51:51 +0100443 if (test_thread_flag(TIF_BLOCKSTEP)) {
444 unsigned long debugctl = get_debugctlmsr();
445
446 debugctl &= ~DEBUGCTLMSR_BTF;
447 update_debugctlmsr(debugctl);
448 }
Roland McGrath1ecc7982008-01-30 13:30:54 +0100449}
450
Harvey Harrisone7b5e112008-01-30 13:31:43 +0100451static void __kprobes restore_btf(void)
Roland McGrath1ecc7982008-01-30 13:30:54 +0100452{
Peter Zijlstraea8e61b2010-03-25 14:51:51 +0100453 if (test_thread_flag(TIF_BLOCKSTEP)) {
454 unsigned long debugctl = get_debugctlmsr();
455
456 debugctl |= DEBUGCTLMSR_BTF;
457 update_debugctlmsr(debugctl);
458 }
Roland McGrath1ecc7982008-01-30 13:30:54 +0100459}
460
Masami Hiramatsu3f33ab12012-03-05 22:32:22 +0900461void __kprobes
462arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs)
Rusty Lynch73649da2005-06-23 00:09:23 -0700463{
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100464 unsigned long *sara = stack_addr(regs);
Rusty Lynch73649da2005-06-23 00:09:23 -0700465
Christoph Hellwig4c4308c2007-05-08 00:34:14 -0700466 ri->ret_addr = (kprobe_opcode_t *) *sara;
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100467
Christoph Hellwig4c4308c2007-05-08 00:34:14 -0700468 /* Replace the return addr with trampoline addr */
469 *sara = (unsigned long) &kretprobe_trampoline;
Rusty Lynch73649da2005-06-23 00:09:23 -0700470}
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100471
Masami Hiramatsu3f33ab12012-03-05 22:32:22 +0900472static void __kprobes
473setup_singlestep(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb, int reenter)
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100474{
Masami Hiramatsuc0f7ac32010-02-25 08:34:46 -0500475 if (setup_detour_execution(p, regs, reenter))
476 return;
477
Masami Hiramatsu615d0eb2010-02-02 16:49:04 -0500478#if !defined(CONFIG_PREEMPT)
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100479 if (p->ainsn.boostable == 1 && !p->post_handler) {
480 /* Boost up -- we can execute copied instructions directly */
Masami Hiramatsu0f94eb62010-02-25 08:34:23 -0500481 if (!reenter)
482 reset_current_kprobe();
483 /*
484 * Reentering boosted probe doesn't reset current_kprobe,
485 * nor set current_kprobe, because it doesn't use single
486 * stepping.
487 */
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100488 regs->ip = (unsigned long)p->ainsn.insn;
489 preempt_enable_no_resched();
490 return;
491 }
492#endif
Masami Hiramatsu0f94eb62010-02-25 08:34:23 -0500493 if (reenter) {
494 save_previous_kprobe(kcb);
495 set_current_kprobe(p, regs, kcb);
496 kcb->kprobe_status = KPROBE_REENTER;
497 } else
498 kcb->kprobe_status = KPROBE_HIT_SS;
499 /* Prepare real single stepping */
500 clear_btf();
501 regs->flags |= X86_EFLAGS_TF;
502 regs->flags &= ~X86_EFLAGS_IF;
503 /* single step inline if the instruction is an int3 */
504 if (p->opcode == BREAKPOINT_INSTRUCTION)
505 regs->ip = (unsigned long)p->addr;
506 else
507 regs->ip = (unsigned long)p->ainsn.insn;
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100508}
509
Harvey Harrison40102d42008-01-30 13:32:02 +0100510/*
511 * We have reentered the kprobe_handler(), since another probe was hit while
512 * within the handler. We save the original kprobes variables and just single
513 * step on the instruction of the new probe without calling any user handlers.
514 */
Masami Hiramatsu3f33ab12012-03-05 22:32:22 +0900515static int __kprobes
516reenter_kprobe(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb)
Harvey Harrison40102d42008-01-30 13:32:02 +0100517{
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100518 switch (kcb->kprobe_status) {
519 case KPROBE_HIT_SSDONE:
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100520 case KPROBE_HIT_ACTIVE:
Abhishek Sagarfb8830e2008-01-30 13:33:13 +0100521 kprobes_inc_nmissed_count(p);
Masami Hiramatsu0f94eb62010-02-25 08:34:23 -0500522 setup_singlestep(p, regs, kcb, 1);
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100523 break;
524 case KPROBE_HIT_SS:
Masami Hiramatsue9afe9e2009-08-27 13:22:58 -0400525 /* A probe has been hit in the codepath leading up to, or just
526 * after, single-stepping of a probed instruction. This entire
527 * codepath should strictly reside in .kprobes.text section.
528 * Raise a BUG or we'll continue in an endless reentering loop
529 * and eventually a stack overflow.
530 */
531 printk(KERN_WARNING "Unrecoverable kprobe detected at %p.\n",
532 p->addr);
533 dump_kprobe(p);
534 BUG();
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100535 default:
536 /* impossible cases */
537 WARN_ON(1);
Abhishek Sagarfb8830e2008-01-30 13:33:13 +0100538 return 0;
Masami Hiramatsu59e87cd2008-01-30 13:32:02 +0100539 }
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100540
Masami Hiramatsu59e87cd2008-01-30 13:32:02 +0100541 return 1;
Harvey Harrison40102d42008-01-30 13:32:02 +0100542}
Rusty Lynch73649da2005-06-23 00:09:23 -0700543
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100544/*
545 * Interrupts are disabled on entry as trap3 is an interrupt gate and they
André Goddard Rosaaf901ca2009-11-14 13:09:05 -0200546 * remain disabled throughout this function.
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100547 */
548static int __kprobes kprobe_handler(struct pt_regs *regs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549{
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100550 kprobe_opcode_t *addr;
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100551 struct kprobe *p;
Ananth N Mavinakayanahallid217d542005-11-07 01:00:14 -0800552 struct kprobe_ctlblk *kcb;
553
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100554 addr = (kprobe_opcode_t *)(regs->ip - sizeof(kprobe_opcode_t));
Ananth N Mavinakayanahallid217d542005-11-07 01:00:14 -0800555 /*
556 * We don't want to be preempted for the entire
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100557 * duration of kprobe processing. We conditionally
558 * re-enable preemption at the end of this function,
559 * and also in reenter_kprobe() and setup_singlestep().
Ananth N Mavinakayanahallid217d542005-11-07 01:00:14 -0800560 */
561 preempt_disable();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100563 kcb = get_kprobe_ctlblk();
Harvey Harrisonb9760152008-01-30 13:32:19 +0100564 p = get_kprobe(addr);
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100565
Harvey Harrisonb9760152008-01-30 13:32:19 +0100566 if (p) {
Harvey Harrisonb9760152008-01-30 13:32:19 +0100567 if (kprobe_running()) {
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100568 if (reenter_kprobe(p, regs, kcb))
569 return 1;
Harvey Harrisonb9760152008-01-30 13:32:19 +0100570 } else {
571 set_current_kprobe(p, regs, kcb);
572 kcb->kprobe_status = KPROBE_HIT_ACTIVE;
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100573
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574 /*
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100575 * If we have no pre-handler or it returned 0, we
576 * continue with normal processing. If we have a
577 * pre-handler and it returned non-zero, it prepped
578 * for calling the break_handler below on re-entry
579 * for jprobe processing, so get out doing nothing
580 * more here.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581 */
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100582 if (!p->pre_handler || !p->pre_handler(p, regs))
Masami Hiramatsu0f94eb62010-02-25 08:34:23 -0500583 setup_singlestep(p, regs, kcb, 0);
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100584 return 1;
Harvey Harrisonb9760152008-01-30 13:32:19 +0100585 }
Masami Hiramatsu829e9242010-04-27 18:33:49 -0400586 } else if (*addr != BREAKPOINT_INSTRUCTION) {
587 /*
588 * The breakpoint instruction was removed right
589 * after we hit it. Another cpu has removed
590 * either a probepoint or a debugger breakpoint
591 * at this address. In either case, no further
592 * handling of this interrupt is appropriate.
593 * Back up over the (now missing) int3 and run
594 * the original instruction.
595 */
596 regs->ip = (unsigned long)addr;
597 preempt_enable_no_resched();
598 return 1;
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100599 } else if (kprobe_running()) {
Christoph Lameterb76834b2010-12-06 11:16:25 -0600600 p = __this_cpu_read(current_kprobe);
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100601 if (p->break_handler && p->break_handler(p, regs)) {
Masami Hiramatsue7dbfe32012-09-28 17:15:20 +0900602 if (!skip_singlestep(p, regs, kcb))
603 setup_singlestep(p, regs, kcb, 0);
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100604 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605 }
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100606 } /* else: not a kprobe fault; let the kernel handle it */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607
Ananth N Mavinakayanahallid217d542005-11-07 01:00:14 -0800608 preempt_enable_no_resched();
Abhishek Sagarf315dec2008-01-30 13:32:50 +0100609 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610}
611
612/*
Masami Hiramatsuda07ab02008-01-30 13:31:21 +0100613 * When a retprobed function returns, this code saves registers and
614 * calls trampoline_handler() runs, which calls the kretprobe's handler.
Rusty Lynch73649da2005-06-23 00:09:23 -0700615 */
Harvey Harrisonf1452d42008-02-14 15:23:53 -0800616static void __used __kprobes kretprobe_trampoline_holder(void)
Harvey Harrison10175792008-01-30 13:33:01 +0100617{
Masami Hiramatsud6be29b2008-01-30 13:31:21 +0100618 asm volatile (
619 ".global kretprobe_trampoline\n"
Masami Hiramatsuda07ab02008-01-30 13:31:21 +0100620 "kretprobe_trampoline: \n"
Masami Hiramatsud6be29b2008-01-30 13:31:21 +0100621#ifdef CONFIG_X86_64
Masami Hiramatsuda07ab02008-01-30 13:31:21 +0100622 /* We don't bother saving the ss register */
623 " pushq %rsp\n"
624 " pushfq\n"
Masami Hiramatsuf007ea22010-02-25 08:34:30 -0500625 SAVE_REGS_STRING
Masami Hiramatsuda07ab02008-01-30 13:31:21 +0100626 " movq %rsp, %rdi\n"
627 " call trampoline_handler\n"
628 /* Replace saved sp with true return address. */
629 " movq %rax, 152(%rsp)\n"
Masami Hiramatsuf007ea22010-02-25 08:34:30 -0500630 RESTORE_REGS_STRING
Masami Hiramatsuda07ab02008-01-30 13:31:21 +0100631 " popfq\n"
Masami Hiramatsud6be29b2008-01-30 13:31:21 +0100632#else
633 " pushf\n"
Masami Hiramatsuf007ea22010-02-25 08:34:30 -0500634 SAVE_REGS_STRING
Masami Hiramatsud6be29b2008-01-30 13:31:21 +0100635 " movl %esp, %eax\n"
636 " call trampoline_handler\n"
637 /* Move flags to cs */
Masami Hiramatsufee039a2009-03-23 10:14:52 -0400638 " movl 56(%esp), %edx\n"
639 " movl %edx, 52(%esp)\n"
Masami Hiramatsud6be29b2008-01-30 13:31:21 +0100640 /* Replace saved flags with true return address. */
Masami Hiramatsufee039a2009-03-23 10:14:52 -0400641 " movl %eax, 56(%esp)\n"
Masami Hiramatsuf007ea22010-02-25 08:34:30 -0500642 RESTORE_REGS_STRING
Masami Hiramatsud6be29b2008-01-30 13:31:21 +0100643 " popf\n"
644#endif
Masami Hiramatsuda07ab02008-01-30 13:31:21 +0100645 " ret\n");
Harvey Harrison10175792008-01-30 13:33:01 +0100646}
Rusty Lynch73649da2005-06-23 00:09:23 -0700647
648/*
Masami Hiramatsuda07ab02008-01-30 13:31:21 +0100649 * Called from kretprobe_trampoline
Rusty Lynch73649da2005-06-23 00:09:23 -0700650 */
Harvey Harrisonf1452d42008-02-14 15:23:53 -0800651static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
Rusty Lynch73649da2005-06-23 00:09:23 -0700652{
bibo,mao62c27be2006-10-02 02:17:33 -0700653 struct kretprobe_instance *ri = NULL;
bibo,mao99219a32006-10-02 02:17:35 -0700654 struct hlist_head *head, empty_rp;
Sasha Levinb67bfe02013-02-27 17:06:00 -0800655 struct hlist_node *tmp;
Ananth N Mavinakayanahalli991a51d2005-11-07 01:00:14 -0800656 unsigned long flags, orig_ret_address = 0;
Masami Hiramatsud6be29b2008-01-30 13:31:21 +0100657 unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline;
KUMANO Syuhei737480a2010-08-15 15:18:04 +0900658 kprobe_opcode_t *correct_ret_addr = NULL;
Rusty Lynch73649da2005-06-23 00:09:23 -0700659
bibo,mao99219a32006-10-02 02:17:35 -0700660 INIT_HLIST_HEAD(&empty_rp);
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700661 kretprobe_hash_lock(current, &head, &flags);
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100662 /* fixup registers */
Masami Hiramatsud6be29b2008-01-30 13:31:21 +0100663#ifdef CONFIG_X86_64
Masami Hiramatsuda07ab02008-01-30 13:31:21 +0100664 regs->cs = __KERNEL_CS;
Masami Hiramatsud6be29b2008-01-30 13:31:21 +0100665#else
666 regs->cs = __KERNEL_CS | get_kernel_rpl();
Masami Hiramatsufee039a2009-03-23 10:14:52 -0400667 regs->gs = 0;
Masami Hiramatsud6be29b2008-01-30 13:31:21 +0100668#endif
Masami Hiramatsuda07ab02008-01-30 13:31:21 +0100669 regs->ip = trampoline_address;
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100670 regs->orig_ax = ~0UL;
Rusty Lynch73649da2005-06-23 00:09:23 -0700671
Rusty Lynchba8af122005-06-27 15:17:10 -0700672 /*
673 * It is possible to have multiple instances associated with a given
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100674 * task either because multiple functions in the call path have
Frederik Schwarzer025dfda2008-10-16 19:02:37 +0200675 * return probes installed on them, and/or more than one
Rusty Lynchba8af122005-06-27 15:17:10 -0700676 * return probe was registered for a target function.
677 *
678 * We can handle this because:
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100679 * - instances are always pushed into the head of the list
Rusty Lynchba8af122005-06-27 15:17:10 -0700680 * - when multiple return probes are registered for the same
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100681 * function, the (chronologically) first instance's ret_addr
682 * will be the real return address, and all the rest will
683 * point to kretprobe_trampoline.
Rusty Lynchba8af122005-06-27 15:17:10 -0700684 */
Sasha Levinb67bfe02013-02-27 17:06:00 -0800685 hlist_for_each_entry_safe(ri, tmp, head, hlist) {
bibo,mao62c27be2006-10-02 02:17:33 -0700686 if (ri->task != current)
Rusty Lynchba8af122005-06-27 15:17:10 -0700687 /* another task is sharing our hash bucket */
bibo,mao62c27be2006-10-02 02:17:33 -0700688 continue;
Rusty Lynch73649da2005-06-23 00:09:23 -0700689
Rusty Lynchba8af122005-06-27 15:17:10 -0700690 orig_ret_address = (unsigned long)ri->ret_addr;
Rusty Lynchba8af122005-06-27 15:17:10 -0700691
692 if (orig_ret_address != trampoline_address)
693 /*
694 * This is the real return address. Any other
695 * instances associated with this task are for
696 * other calls deeper on the call stack
697 */
698 break;
Rusty Lynch73649da2005-06-23 00:09:23 -0700699 }
Rusty Lynchba8af122005-06-27 15:17:10 -0700700
Ananth N Mavinakayanahalli0f95b7f2007-05-08 00:28:27 -0700701 kretprobe_assert(ri, orig_ret_address, trampoline_address);
Rusty Lynchba8af122005-06-27 15:17:10 -0700702
KUMANO Syuhei737480a2010-08-15 15:18:04 +0900703 correct_ret_addr = ri->ret_addr;
Sasha Levinb67bfe02013-02-27 17:06:00 -0800704 hlist_for_each_entry_safe(ri, tmp, head, hlist) {
KUMANO Syuhei737480a2010-08-15 15:18:04 +0900705 if (ri->task != current)
706 /* another task is sharing our hash bucket */
707 continue;
708
709 orig_ret_address = (unsigned long)ri->ret_addr;
710 if (ri->rp && ri->rp->handler) {
Christoph Lameterb76834b2010-12-06 11:16:25 -0600711 __this_cpu_write(current_kprobe, &ri->rp->kp);
KUMANO Syuhei737480a2010-08-15 15:18:04 +0900712 get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE;
713 ri->ret_addr = correct_ret_addr;
714 ri->rp->handler(ri, regs);
Christoph Lameterb76834b2010-12-06 11:16:25 -0600715 __this_cpu_write(current_kprobe, NULL);
KUMANO Syuhei737480a2010-08-15 15:18:04 +0900716 }
717
718 recycle_rp_inst(ri, &empty_rp);
719
720 if (orig_ret_address != trampoline_address)
721 /*
722 * This is the real return address. Any other
723 * instances associated with this task are for
724 * other calls deeper on the call stack
725 */
726 break;
727 }
728
Srinivasa D Sef53d9c2008-07-25 01:46:04 -0700729 kretprobe_hash_unlock(current, &flags);
Rusty Lynchba8af122005-06-27 15:17:10 -0700730
Sasha Levinb67bfe02013-02-27 17:06:00 -0800731 hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
bibo,mao99219a32006-10-02 02:17:35 -0700732 hlist_del(&ri->hlist);
733 kfree(ri);
734 }
Masami Hiramatsuda07ab02008-01-30 13:31:21 +0100735 return (void *)orig_ret_address;
Rusty Lynch73649da2005-06-23 00:09:23 -0700736}
737
738/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700739 * Called after single-stepping. p->addr is the address of the
740 * instruction whose first byte has been replaced by the "int 3"
741 * instruction. To avoid the SMP problems that can occur when we
742 * temporarily put back the original opcode to single-step, we
743 * single-stepped a copy of the instruction. The address of this
744 * copy is p->ainsn.insn.
745 *
746 * This function prepares to return from the post-single-step
747 * interrupt. We have to fix up the stack as follows:
748 *
749 * 0) Except in the case of absolute or indirect jump or call instructions,
H. Peter Anvin65ea5b02008-01-30 13:30:56 +0100750 * the new ip is relative to the copied instruction. We need to make
Linus Torvalds1da177e2005-04-16 15:20:36 -0700751 * it relative to the original instruction.
752 *
753 * 1) If the single-stepped instruction was pushfl, then the TF and IF
H. Peter Anvin65ea5b02008-01-30 13:30:56 +0100754 * flags are set in the just-pushed flags, and may need to be cleared.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700755 *
756 * 2) If the single-stepped instruction was a call, the return address
757 * that is atop the stack is the address following the copied instruction.
758 * We need to make it the address following the original instruction.
Masami Hiramatsuaa470142008-01-30 13:31:21 +0100759 *
760 * If this is the first time we've single-stepped the instruction at
761 * this probepoint, and the instruction is boostable, boost it: add a
762 * jump instruction after the copied instruction, that jumps to the next
763 * instruction after the probepoint.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764 */
Masami Hiramatsu3f33ab12012-03-05 22:32:22 +0900765static void __kprobes
766resume_execution(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767{
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100768 unsigned long *tos = stack_addr(regs);
769 unsigned long copy_ip = (unsigned long)p->ainsn.insn;
770 unsigned long orig_ip = (unsigned long)p->addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700771 kprobe_opcode_t *insn = p->ainsn.insn;
772
Masami Hiramatsu567a9fd2010-06-29 14:53:50 +0900773 /* Skip prefixes */
774 insn = skip_prefixes(insn);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775
Glauber de Oliveira Costa053de042008-01-30 13:31:27 +0100776 regs->flags &= ~X86_EFLAGS_TF;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777 switch (*insn) {
Masami Hiramatsu0b0122f2007-12-18 18:05:58 +0100778 case 0x9c: /* pushfl */
Glauber de Oliveira Costa053de042008-01-30 13:31:27 +0100779 *tos &= ~(X86_EFLAGS_TF | X86_EFLAGS_IF);
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100780 *tos |= kcb->kprobe_old_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781 break;
Masami Hiramatsu0b0122f2007-12-18 18:05:58 +0100782 case 0xc2: /* iret/ret/lret */
783 case 0xc3:
Prasanna S Panchamukhi0b9e2ca2005-05-05 16:15:40 -0700784 case 0xca:
Masami Hiramatsu0b0122f2007-12-18 18:05:58 +0100785 case 0xcb:
786 case 0xcf:
787 case 0xea: /* jmp absolute -- ip is correct */
788 /* ip is already adjusted, no more changes required */
Masami Hiramatsuaa470142008-01-30 13:31:21 +0100789 p->ainsn.boostable = 1;
Masami Hiramatsu0b0122f2007-12-18 18:05:58 +0100790 goto no_change;
791 case 0xe8: /* call relative - Fix return addr */
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100792 *tos = orig_ip + (*tos - copy_ip);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793 break;
Harvey Harrisone7b5e112008-01-30 13:31:43 +0100794#ifdef CONFIG_X86_32
Masami Hiramatsud6be29b2008-01-30 13:31:21 +0100795 case 0x9a: /* call absolute -- same as call absolute, indirect */
796 *tos = orig_ip + (*tos - copy_ip);
797 goto no_change;
798#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799 case 0xff:
Satoshi Oshimadc49e342006-05-20 15:00:21 -0700800 if ((insn[1] & 0x30) == 0x10) {
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100801 /*
802 * call absolute, indirect
803 * Fix return addr; ip is correct.
804 * But this is not boostable
805 */
806 *tos = orig_ip + (*tos - copy_ip);
Masami Hiramatsu0b0122f2007-12-18 18:05:58 +0100807 goto no_change;
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100808 } else if (((insn[1] & 0x31) == 0x20) ||
809 ((insn[1] & 0x31) == 0x21)) {
810 /*
811 * jmp near and far, absolute indirect
812 * ip is correct. And this is boostable
813 */
Masami Hiramatsuaa470142008-01-30 13:31:21 +0100814 p->ainsn.boostable = 1;
Masami Hiramatsu0b0122f2007-12-18 18:05:58 +0100815 goto no_change;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700817 default:
818 break;
819 }
820
Masami Hiramatsuaa470142008-01-30 13:31:21 +0100821 if (p->ainsn.boostable == 0) {
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100822 if ((regs->ip > copy_ip) &&
823 (regs->ip - copy_ip) + 5 < MAX_INSN_SIZE) {
Masami Hiramatsuaa470142008-01-30 13:31:21 +0100824 /*
825 * These instructions can be executed directly if it
826 * jumps back to correct address.
827 */
Masami Hiramatsuc0f7ac32010-02-25 08:34:46 -0500828 synthesize_reljump((void *)regs->ip,
829 (void *)orig_ip + (regs->ip - copy_ip));
Masami Hiramatsuaa470142008-01-30 13:31:21 +0100830 p->ainsn.boostable = 1;
831 } else {
832 p->ainsn.boostable = -1;
833 }
834 }
835
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100836 regs->ip += orig_ip - copy_ip;
H. Peter Anvin65ea5b02008-01-30 13:30:56 +0100837
Masami Hiramatsu0b0122f2007-12-18 18:05:58 +0100838no_change:
Roland McGrath1ecc7982008-01-30 13:30:54 +0100839 restore_btf();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840}
841
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100842/*
843 * Interrupts are disabled on entry as trap1 is an interrupt gate and they
André Goddard Rosaaf901ca2009-11-14 13:09:05 -0200844 * remain disabled throughout this function.
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100845 */
846static int __kprobes post_kprobe_handler(struct pt_regs *regs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700847{
Ananth N Mavinakayanahallie7a510f2005-11-07 01:00:12 -0800848 struct kprobe *cur = kprobe_running();
849 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
850
851 if (!cur)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700852 return 0;
853
Yakov Lerneracb5b8a2008-03-16 03:21:21 -0500854 resume_execution(cur, regs, kcb);
855 regs->flags |= kcb->kprobe_saved_flags;
Yakov Lerneracb5b8a2008-03-16 03:21:21 -0500856
Ananth N Mavinakayanahallie7a510f2005-11-07 01:00:12 -0800857 if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
858 kcb->kprobe_status = KPROBE_HIT_SSDONE;
859 cur->post_handler(cur, regs, 0);
Prasanna S Panchamukhiaa3d7e32005-06-23 00:09:37 -0700860 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100862 /* Restore back the original saved kprobes variables and continue. */
Ananth N Mavinakayanahallie7a510f2005-11-07 01:00:12 -0800863 if (kcb->kprobe_status == KPROBE_REENTER) {
864 restore_previous_kprobe(kcb);
Prasanna S Panchamukhiaa3d7e32005-06-23 00:09:37 -0700865 goto out;
Prasanna S Panchamukhiaa3d7e32005-06-23 00:09:37 -0700866 }
Ananth N Mavinakayanahallie7a510f2005-11-07 01:00:12 -0800867 reset_current_kprobe();
Prasanna S Panchamukhiaa3d7e32005-06-23 00:09:37 -0700868out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700869 preempt_enable_no_resched();
870
871 /*
H. Peter Anvin65ea5b02008-01-30 13:30:56 +0100872 * if somebody else is singlestepping across a probe point, flags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700873 * will have TF set, in which case, continue the remaining processing
874 * of do_debug, as if this is not a probe hit.
875 */
Glauber de Oliveira Costa053de042008-01-30 13:31:27 +0100876 if (regs->flags & X86_EFLAGS_TF)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877 return 0;
878
879 return 1;
880}
881
Prasanna S Panchamukhi0f2fbdc2005-09-06 15:19:28 -0700882int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700883{
Ananth N Mavinakayanahallie7a510f2005-11-07 01:00:12 -0800884 struct kprobe *cur = kprobe_running();
885 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
886
Masami Hiramatsud6be29b2008-01-30 13:31:21 +0100887 switch (kcb->kprobe_status) {
Prasanna S Panchamukhic28f8962006-03-26 01:38:23 -0800888 case KPROBE_HIT_SS:
889 case KPROBE_REENTER:
890 /*
891 * We are here because the instruction being single
892 * stepped caused a page fault. We reset the current
H. Peter Anvin65ea5b02008-01-30 13:30:56 +0100893 * kprobe and the ip points back to the probe address
Prasanna S Panchamukhic28f8962006-03-26 01:38:23 -0800894 * and allow the page fault handler to continue as a
895 * normal page fault.
896 */
H. Peter Anvin65ea5b02008-01-30 13:30:56 +0100897 regs->ip = (unsigned long)cur->addr;
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100898 regs->flags |= kcb->kprobe_old_flags;
Prasanna S Panchamukhic28f8962006-03-26 01:38:23 -0800899 if (kcb->kprobe_status == KPROBE_REENTER)
900 restore_previous_kprobe(kcb);
901 else
902 reset_current_kprobe();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903 preempt_enable_no_resched();
Prasanna S Panchamukhic28f8962006-03-26 01:38:23 -0800904 break;
905 case KPROBE_HIT_ACTIVE:
906 case KPROBE_HIT_SSDONE:
907 /*
908 * We increment the nmissed count for accounting,
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100909 * we can also use npre/npostfault count for accounting
Prasanna S Panchamukhic28f8962006-03-26 01:38:23 -0800910 * these specific fault cases.
911 */
912 kprobes_inc_nmissed_count(cur);
913
914 /*
915 * We come here because instructions in the pre/post
916 * handler caused the page_fault, this could happen
917 * if handler tries to access user space by
918 * copy_from_user(), get_user() etc. Let the
919 * user-specified handler try to fix it first.
920 */
921 if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
922 return 1;
923
924 /*
925 * In case the user-specified fault handler returned
926 * zero, try to fix up.
927 */
Masami Hiramatsud6be29b2008-01-30 13:31:21 +0100928 if (fixup_exception(regs))
929 return 1;
Harvey Harrison6d485832008-01-30 13:31:41 +0100930
Prasanna S Panchamukhic28f8962006-03-26 01:38:23 -0800931 /*
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100932 * fixup routine could not handle it,
Prasanna S Panchamukhic28f8962006-03-26 01:38:23 -0800933 * Let do_page_fault() fix it.
934 */
935 break;
936 default:
937 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700938 }
939 return 0;
940}
941
942/*
943 * Wrapper routine for handling exceptions.
944 */
Masami Hiramatsu3f33ab12012-03-05 22:32:22 +0900945int __kprobes
946kprobe_exceptions_notify(struct notifier_block *self, unsigned long val, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700947{
Jan Engelhardtade1af72008-01-30 13:33:23 +0100948 struct die_args *args = data;
Ananth N Mavinakayanahalli66ff2d062005-11-07 01:00:07 -0800949 int ret = NOTIFY_DONE;
950
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100951 if (args->regs && user_mode_vm(args->regs))
bibo,mao2326c772006-03-26 01:38:21 -0800952 return ret;
953
Linus Torvalds1da177e2005-04-16 15:20:36 -0700954 switch (val) {
955 case DIE_INT3:
956 if (kprobe_handler(args->regs))
Ananth N Mavinakayanahalli66ff2d062005-11-07 01:00:07 -0800957 ret = NOTIFY_STOP;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700958 break;
959 case DIE_DEBUG:
K.Prasad62edab92009-06-01 23:47:06 +0530960 if (post_kprobe_handler(args->regs)) {
961 /*
962 * Reset the BS bit in dr6 (pointed by args->err) to
963 * denote completion of processing
964 */
965 (*(unsigned long *)ERR_PTR(args->err)) &= ~DR_STEP;
Ananth N Mavinakayanahalli66ff2d062005-11-07 01:00:07 -0800966 ret = NOTIFY_STOP;
K.Prasad62edab92009-06-01 23:47:06 +0530967 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700968 break;
969 case DIE_GPF:
Quentin Barnesb506a9d2008-01-30 13:32:32 +0100970 /*
971 * To be potentially processing a kprobe fault and to
972 * trust the result from kprobe_running(), we have
973 * be non-preemptible.
974 */
975 if (!preemptible() && kprobe_running() &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976 kprobe_fault_handler(args->regs, args->trapnr))
Ananth N Mavinakayanahalli66ff2d062005-11-07 01:00:07 -0800977 ret = NOTIFY_STOP;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700978 break;
979 default:
980 break;
981 }
Ananth N Mavinakayanahalli66ff2d062005-11-07 01:00:07 -0800982 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700983}
984
Prasanna S Panchamukhi0f2fbdc2005-09-06 15:19:28 -0700985int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700986{
987 struct jprobe *jp = container_of(p, struct jprobe, kp);
988 unsigned long addr;
Ananth N Mavinakayanahallie7a510f2005-11-07 01:00:12 -0800989 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700990
Ananth N Mavinakayanahallie7a510f2005-11-07 01:00:12 -0800991 kcb->jprobe_saved_regs = *regs;
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +0100992 kcb->jprobe_saved_sp = stack_addr(regs);
993 addr = (unsigned long)(kcb->jprobe_saved_sp);
994
Linus Torvalds1da177e2005-04-16 15:20:36 -0700995 /*
996 * As Linus pointed out, gcc assumes that the callee
997 * owns the argument space and could overwrite it, e.g.
998 * tailcall optimization. So, to be absolutely safe
999 * we also save and restore enough stack bytes to cover
1000 * the argument area.
1001 */
Ananth N Mavinakayanahallie7a510f2005-11-07 01:00:12 -08001002 memcpy(kcb->jprobes_stack, (kprobe_opcode_t *)addr,
Masami Hiramatsud6be29b2008-01-30 13:31:21 +01001003 MIN_STACK_SIZE(addr));
Glauber de Oliveira Costa053de042008-01-30 13:31:27 +01001004 regs->flags &= ~X86_EFLAGS_IF;
Peter Zijlstra58dfe882007-10-11 22:25:25 +02001005 trace_hardirqs_off();
H. Peter Anvin65ea5b02008-01-30 13:30:56 +01001006 regs->ip = (unsigned long)(jp->entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001007 return 1;
1008}
1009
Prasanna S Panchamukhi0f2fbdc2005-09-06 15:19:28 -07001010void __kprobes jprobe_return(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001011{
Ananth N Mavinakayanahallie7a510f2005-11-07 01:00:12 -08001012 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
1013
Masami Hiramatsud6be29b2008-01-30 13:31:21 +01001014 asm volatile (
1015#ifdef CONFIG_X86_64
1016 " xchg %%rbx,%%rsp \n"
1017#else
1018 " xchgl %%ebx,%%esp \n"
1019#endif
1020 " int3 \n"
1021 " .globl jprobe_return_end\n"
1022 " jprobe_return_end: \n"
1023 " nop \n"::"b"
1024 (kcb->jprobe_saved_sp):"memory");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001025}
1026
Prasanna S Panchamukhi0f2fbdc2005-09-06 15:19:28 -07001027int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001028{
Ananth N Mavinakayanahallie7a510f2005-11-07 01:00:12 -08001029 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
H. Peter Anvin65ea5b02008-01-30 13:30:56 +01001030 u8 *addr = (u8 *) (regs->ip - 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001031 struct jprobe *jp = container_of(p, struct jprobe, kp);
1032
Masami Hiramatsud6be29b2008-01-30 13:31:21 +01001033 if ((addr > (u8 *) jprobe_return) &&
1034 (addr < (u8 *) jprobe_return_end)) {
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +01001035 if (stack_addr(regs) != kcb->jprobe_saved_sp) {
Masami Hiramatsu29b6cd72007-12-18 18:05:58 +01001036 struct pt_regs *saved_regs = &kcb->jprobe_saved_regs;
Masami Hiramatsud6be29b2008-01-30 13:31:21 +01001037 printk(KERN_ERR
1038 "current sp %p does not match saved sp %p\n",
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +01001039 stack_addr(regs), kcb->jprobe_saved_sp);
Masami Hiramatsud6be29b2008-01-30 13:31:21 +01001040 printk(KERN_ERR "Saved registers for jprobe %p\n", jp);
Jan Beulich57da8b92012-05-09 08:47:37 +01001041 show_regs(saved_regs);
Masami Hiramatsud6be29b2008-01-30 13:31:21 +01001042 printk(KERN_ERR "Current registers\n");
Jan Beulich57da8b92012-05-09 08:47:37 +01001043 show_regs(regs);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001044 BUG();
1045 }
Ananth N Mavinakayanahallie7a510f2005-11-07 01:00:12 -08001046 *regs = kcb->jprobe_saved_regs;
Masami Hiramatsu8533bbe2008-01-30 13:31:21 +01001047 memcpy((kprobe_opcode_t *)(kcb->jprobe_saved_sp),
1048 kcb->jprobes_stack,
1049 MIN_STACK_SIZE(kcb->jprobe_saved_sp));
Ananth N Mavinakayanahallid217d542005-11-07 01:00:14 -08001050 preempt_enable_no_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001051 return 1;
1052 }
1053 return 0;
1054}
Rusty Lynchba8af122005-06-27 15:17:10 -07001055
Rusty Lynch67729262005-07-05 18:54:50 -07001056int __init arch_init_kprobes(void)
Rusty Lynchba8af122005-06-27 15:17:10 -07001057{
Masami Hiramatsu3f33ab12012-03-05 22:32:22 +09001058 return arch_init_optprobes();
Rusty Lynchba8af122005-06-27 15:17:10 -07001059}
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001060
1061int __kprobes arch_trampoline_kprobe(struct kprobe *p)
1062{
Ananth N Mavinakayanahallibf8f6e5b2007-05-08 00:34:16 -07001063 return 0;
1064}