2 * Kernel Probes (KProbes)
3 * arch/i386/kernel/kprobes.c
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19 * Copyright (C) IBM Corporation, 2002, 2004
21 * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
22 * Probes initial implementation ( includes contributions from
24 * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
25 * interface to access function arguments.
26 * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston
27 * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
28 * <prasanna@in.ibm.com> added function-return probes.
31 #include <linux/kprobes.h>
32 #include <linux/ptrace.h>
33 #include <linux/preempt.h>
34 #include <asm/cacheflush.h>
35 #include <asm/kdebug.h>
37 #include <asm/uaccess.h>
39 void jprobe_return_end(void);
41 DEFINE_PER_CPU(struct kprobe
*, current_kprobe
) = NULL
;
42 DEFINE_PER_CPU(struct kprobe_ctlblk
, kprobe_ctlblk
);
44 /* insert a jmp code */
45 static __always_inline
void set_jmp_op(void *from
, void *to
)
47 struct __arch_jmp_op
{
50 } __attribute__((packed
)) *jop
;
51 jop
= (struct __arch_jmp_op
*)from
;
52 jop
->raddr
= (long)(to
) - ((long)(from
) + 5);
53 jop
->op
= RELATIVEJUMP_INSTRUCTION
;
57 * returns non-zero if opcodes can be boosted.
59 static __always_inline
int can_boost(kprobe_opcode_t
*opcodes
)
61 #define W(row,b0,b1,b2,b3,b4,b5,b6,b7,b8,b9,ba,bb,bc,bd,be,bf) \
62 (((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \
63 (b4##UL << 0x4)|(b5##UL << 0x5)|(b6##UL << 0x6)|(b7##UL << 0x7) | \
64 (b8##UL << 0x8)|(b9##UL << 0x9)|(ba##UL << 0xa)|(bb##UL << 0xb) | \
65 (bc##UL << 0xc)|(bd##UL << 0xd)|(be##UL << 0xe)|(bf##UL << 0xf)) \
68 * Undefined/reserved opcodes, conditional jump, Opcode Extension
69 * Groups, and some special opcodes can not be boost.
71 static const unsigned long twobyte_is_boostable
[256 / 32] = {
72 /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
73 /* ------------------------------- */
74 W(0x00, 0,0,1,1,0,0,1,0,1,1,0,0,0,0,0,0)| /* 00 */
75 W(0x10, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 10 */
76 W(0x20, 1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0)| /* 20 */
77 W(0x30, 0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 30 */
78 W(0x40, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 40 */
79 W(0x50, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 50 */
80 W(0x60, 1,1,1,1,1,1,1,1,1,1,1,1,0,0,1,1)| /* 60 */
81 W(0x70, 0,0,0,0,1,1,1,1,0,0,0,0,0,0,1,1), /* 70 */
82 W(0x80, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 80 */
83 W(0x90, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1), /* 90 */
84 W(0xa0, 1,1,0,1,1,1,0,0,1,1,0,1,1,1,0,1)| /* a0 */
85 W(0xb0, 1,1,1,1,1,1,1,1,0,0,0,1,1,1,1,1), /* b0 */
86 W(0xc0, 1,1,0,0,0,0,0,0,1,1,1,1,1,1,1,1)| /* c0 */
87 W(0xd0, 0,1,1,1,0,1,0,0,1,1,0,1,1,1,0,1), /* d0 */
88 W(0xe0, 0,1,1,0,0,1,0,0,1,1,0,1,1,1,0,1)| /* e0 */
89 W(0xf0, 0,1,1,1,0,1,0,0,1,1,1,0,1,1,1,0) /* f0 */
90 /* ------------------------------- */
91 /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
94 kprobe_opcode_t opcode
;
95 kprobe_opcode_t
*orig_opcodes
= opcodes
;
97 if (opcodes
- orig_opcodes
> MAX_INSN_SIZE
- 1)
99 opcode
= *(opcodes
++);
101 /* 2nd-byte opcode */
102 if (opcode
== 0x0f) {
103 if (opcodes
- orig_opcodes
> MAX_INSN_SIZE
- 1)
105 return test_bit(*opcodes
, twobyte_is_boostable
);
108 switch (opcode
& 0xf0) {
110 if (0x63 < opcode
&& opcode
< 0x67)
111 goto retry
; /* prefixes */
112 /* can't boost Address-size override and bound */
113 return (opcode
!= 0x62 && opcode
!= 0x67);
115 return 0; /* can't boost conditional jump */
117 /* can't boost software-interruptions */
118 return (0xc1 < opcode
&& opcode
< 0xcc) || opcode
== 0xcf;
120 /* can boost AA* and XLAT */
121 return (opcode
== 0xd4 || opcode
== 0xd5 || opcode
== 0xd7);
123 /* can boost in/out and absolute jmps */
124 return ((opcode
& 0x04) || opcode
== 0xea);
126 if ((opcode
& 0x0c) == 0 && opcode
!= 0xf1)
127 goto retry
; /* lock/rep(ne) prefix */
128 /* clear and set flags can be boost */
129 return (opcode
== 0xf5 || (0xf7 < opcode
&& opcode
< 0xfe));
131 if (opcode
== 0x26 || opcode
== 0x36 || opcode
== 0x3e)
132 goto retry
; /* prefixes */
133 /* can't boost CS override and call */
134 return (opcode
!= 0x2e && opcode
!= 0x9a);
139 * returns non-zero if opcode modifies the interrupt flag.
141 static int __kprobes
is_IF_modifier(kprobe_opcode_t opcode
)
146 case 0xcf: /* iret/iretd */
147 case 0x9d: /* popf/popfd */
153 int __kprobes
arch_prepare_kprobe(struct kprobe
*p
)
155 /* insn: must be on special executable page on i386. */
156 p
->ainsn
.insn
= get_insn_slot();
160 memcpy(p
->ainsn
.insn
, p
->addr
, MAX_INSN_SIZE
* sizeof(kprobe_opcode_t
));
161 p
->opcode
= *p
->addr
;
162 if (can_boost(p
->addr
)) {
163 p
->ainsn
.boostable
= 0;
165 p
->ainsn
.boostable
= -1;
170 void __kprobes
arch_arm_kprobe(struct kprobe
*p
)
172 *p
->addr
= BREAKPOINT_INSTRUCTION
;
173 flush_icache_range((unsigned long) p
->addr
,
174 (unsigned long) p
->addr
+ sizeof(kprobe_opcode_t
));
177 void __kprobes
arch_disarm_kprobe(struct kprobe
*p
)
179 *p
->addr
= p
->opcode
;
180 flush_icache_range((unsigned long) p
->addr
,
181 (unsigned long) p
->addr
+ sizeof(kprobe_opcode_t
));
184 void __kprobes
arch_remove_kprobe(struct kprobe
*p
)
186 mutex_lock(&kprobe_mutex
);
187 free_insn_slot(p
->ainsn
.insn
);
188 mutex_unlock(&kprobe_mutex
);
191 static void __kprobes
save_previous_kprobe(struct kprobe_ctlblk
*kcb
)
193 kcb
->prev_kprobe
.kp
= kprobe_running();
194 kcb
->prev_kprobe
.status
= kcb
->kprobe_status
;
195 kcb
->prev_kprobe
.old_eflags
= kcb
->kprobe_old_eflags
;
196 kcb
->prev_kprobe
.saved_eflags
= kcb
->kprobe_saved_eflags
;
199 static void __kprobes
restore_previous_kprobe(struct kprobe_ctlblk
*kcb
)
201 __get_cpu_var(current_kprobe
) = kcb
->prev_kprobe
.kp
;
202 kcb
->kprobe_status
= kcb
->prev_kprobe
.status
;
203 kcb
->kprobe_old_eflags
= kcb
->prev_kprobe
.old_eflags
;
204 kcb
->kprobe_saved_eflags
= kcb
->prev_kprobe
.saved_eflags
;
207 static void __kprobes
set_current_kprobe(struct kprobe
*p
, struct pt_regs
*regs
,
208 struct kprobe_ctlblk
*kcb
)
210 __get_cpu_var(current_kprobe
) = p
;
211 kcb
->kprobe_saved_eflags
= kcb
->kprobe_old_eflags
212 = (regs
->eflags
& (TF_MASK
| IF_MASK
));
213 if (is_IF_modifier(p
->opcode
))
214 kcb
->kprobe_saved_eflags
&= ~IF_MASK
;
217 static void __kprobes
prepare_singlestep(struct kprobe
*p
, struct pt_regs
*regs
)
219 regs
->eflags
|= TF_MASK
;
220 regs
->eflags
&= ~IF_MASK
;
221 /*single step inline if the instruction is an int3*/
222 if (p
->opcode
== BREAKPOINT_INSTRUCTION
)
223 regs
->eip
= (unsigned long)p
->addr
;
225 regs
->eip
= (unsigned long)p
->ainsn
.insn
;
228 /* Called with kretprobe_lock held */
229 void __kprobes
arch_prepare_kretprobe(struct kretprobe
*rp
,
230 struct pt_regs
*regs
)
232 unsigned long *sara
= (unsigned long *)®s
->esp
;
233 struct kretprobe_instance
*ri
;
235 if ((ri
= get_free_rp_inst(rp
)) != NULL
) {
238 ri
->ret_addr
= (kprobe_opcode_t
*) *sara
;
240 /* Replace the return addr with trampoline addr */
241 *sara
= (unsigned long) &kretprobe_trampoline
;
250 * Interrupts are disabled on entry as trap3 is an interrupt gate and they
251 * remain disabled thorough out this function.
253 static int __kprobes
kprobe_handler(struct pt_regs
*regs
)
257 kprobe_opcode_t
*addr
;
258 struct kprobe_ctlblk
*kcb
;
259 #ifdef CONFIG_PREEMPT
260 unsigned pre_preempt_count
= preempt_count();
262 unsigned pre_preempt_count
= 1;
265 addr
= (kprobe_opcode_t
*)(regs
->eip
- sizeof(kprobe_opcode_t
));
268 * We don't want to be preempted for the entire
269 * duration of kprobe processing
272 kcb
= get_kprobe_ctlblk();
274 /* Check we're not actually recursing */
275 if (kprobe_running()) {
276 p
= get_kprobe(addr
);
278 if (kcb
->kprobe_status
== KPROBE_HIT_SS
&&
279 *p
->ainsn
.insn
== BREAKPOINT_INSTRUCTION
) {
280 regs
->eflags
&= ~TF_MASK
;
281 regs
->eflags
|= kcb
->kprobe_saved_eflags
;
284 /* We have reentered the kprobe_handler(), since
285 * another probe was hit while within the handler.
286 * We here save the original kprobes variables and
287 * just single step on the instruction of the new probe
288 * without calling any user handlers.
290 save_previous_kprobe(kcb
);
291 set_current_kprobe(p
, regs
, kcb
);
292 kprobes_inc_nmissed_count(p
);
293 prepare_singlestep(p
, regs
);
294 kcb
->kprobe_status
= KPROBE_REENTER
;
297 if (*addr
!= BREAKPOINT_INSTRUCTION
) {
298 /* The breakpoint instruction was removed by
299 * another cpu right after we hit, no further
300 * handling of this interrupt is appropriate
302 regs
->eip
-= sizeof(kprobe_opcode_t
);
306 p
= __get_cpu_var(current_kprobe
);
307 if (p
->break_handler
&& p
->break_handler(p
, regs
)) {
314 p
= get_kprobe(addr
);
316 if (*addr
!= BREAKPOINT_INSTRUCTION
) {
318 * The breakpoint instruction was removed right
319 * after we hit it. Another cpu has removed
320 * either a probepoint or a debugger breakpoint
321 * at this address. In either case, no further
322 * handling of this interrupt is appropriate.
323 * Back up over the (now missing) int3 and run
324 * the original instruction.
326 regs
->eip
-= sizeof(kprobe_opcode_t
);
329 /* Not one of ours: let kernel handle it */
333 set_current_kprobe(p
, regs
, kcb
);
334 kcb
->kprobe_status
= KPROBE_HIT_ACTIVE
;
336 if (p
->pre_handler
&& p
->pre_handler(p
, regs
))
337 /* handler has already set things up, so skip ss setup */
341 if (pre_preempt_count
&& p
->ainsn
.boostable
== 1 && !p
->post_handler
){
342 /* Boost up -- we can execute copied instructions directly */
343 reset_current_kprobe();
344 regs
->eip
= (unsigned long)p
->ainsn
.insn
;
345 preempt_enable_no_resched();
348 prepare_singlestep(p
, regs
);
349 kcb
->kprobe_status
= KPROBE_HIT_SS
;
353 preempt_enable_no_resched();
358 * For function-return probes, init_kprobes() establishes a probepoint
359 * here. When a retprobed function returns, this probe is hit and
360 * trampoline_probe_handler() runs, calling the kretprobe's handler.
362 void __kprobes
kretprobe_trampoline_holder(void)
364 asm volatile ( ".global kretprobe_trampoline\n"
365 "kretprobe_trampoline: \n"
367 /* skip cs, eip, orig_eax, es, ds */
377 " call trampoline_handler\n"
378 /* move eflags to cs */
379 " movl 48(%esp), %edx\n"
380 " movl %edx, 44(%esp)\n"
381 /* save true return address on eflags */
382 " movl %eax, 48(%esp)\n"
390 /* skip eip, orig_eax, es, ds */
397 * Called from kretprobe_trampoline
399 fastcall
void *__kprobes
trampoline_handler(struct pt_regs
*regs
)
401 struct kretprobe_instance
*ri
= NULL
;
402 struct hlist_head
*head
;
403 struct hlist_node
*node
, *tmp
;
404 unsigned long flags
, orig_ret_address
= 0;
405 unsigned long trampoline_address
=(unsigned long)&kretprobe_trampoline
;
407 spin_lock_irqsave(&kretprobe_lock
, flags
);
408 head
= kretprobe_inst_table_head(current
);
411 * It is possible to have multiple instances associated with a given
412 * task either because an multiple functions in the call path
413 * have a return probe installed on them, and/or more then one return
414 * return probe was registered for a target function.
416 * We can handle this because:
417 * - instances are always inserted at the head of the list
418 * - when multiple return probes are registered for the same
419 * function, the first instance's ret_addr will point to the
420 * real return address, and all the rest will point to
421 * kretprobe_trampoline
423 hlist_for_each_entry_safe(ri
, node
, tmp
, head
, hlist
) {
424 if (ri
->task
!= current
)
425 /* another task is sharing our hash bucket */
428 if (ri
->rp
&& ri
->rp
->handler
){
429 __get_cpu_var(current_kprobe
) = &ri
->rp
->kp
;
430 ri
->rp
->handler(ri
, regs
);
431 __get_cpu_var(current_kprobe
) = NULL
;
434 orig_ret_address
= (unsigned long)ri
->ret_addr
;
437 if (orig_ret_address
!= trampoline_address
)
439 * This is the real return address. Any other
440 * instances associated with this task are for
441 * other calls deeper on the call stack
446 BUG_ON(!orig_ret_address
|| (orig_ret_address
== trampoline_address
));
448 spin_unlock_irqrestore(&kretprobe_lock
, flags
);
450 return (void*)orig_ret_address
;
454 * Called after single-stepping. p->addr is the address of the
455 * instruction whose first byte has been replaced by the "int 3"
456 * instruction. To avoid the SMP problems that can occur when we
457 * temporarily put back the original opcode to single-step, we
458 * single-stepped a copy of the instruction. The address of this
459 * copy is p->ainsn.insn.
461 * This function prepares to return from the post-single-step
462 * interrupt. We have to fix up the stack as follows:
464 * 0) Except in the case of absolute or indirect jump or call instructions,
465 * the new eip is relative to the copied instruction. We need to make
466 * it relative to the original instruction.
468 * 1) If the single-stepped instruction was pushfl, then the TF and IF
469 * flags are set in the just-pushed eflags, and may need to be cleared.
471 * 2) If the single-stepped instruction was a call, the return address
472 * that is atop the stack is the address following the copied instruction.
473 * We need to make it the address following the original instruction.
475 * This function also checks instruction size for preparing direct execution.
477 static void __kprobes
resume_execution(struct kprobe
*p
,
478 struct pt_regs
*regs
, struct kprobe_ctlblk
*kcb
)
480 unsigned long *tos
= (unsigned long *)®s
->esp
;
481 unsigned long copy_eip
= (unsigned long)p
->ainsn
.insn
;
482 unsigned long orig_eip
= (unsigned long)p
->addr
;
484 regs
->eflags
&= ~TF_MASK
;
485 switch (p
->ainsn
.insn
[0]) {
486 case 0x9c: /* pushfl */
487 *tos
&= ~(TF_MASK
| IF_MASK
);
488 *tos
|= kcb
->kprobe_old_eflags
;
490 case 0xc2: /* iret/ret/lret */
495 case 0xea: /* jmp absolute -- eip is correct */
496 /* eip is already adjusted, no more changes required */
497 p
->ainsn
.boostable
= 1;
499 case 0xe8: /* call relative - Fix return addr */
500 *tos
= orig_eip
+ (*tos
- copy_eip
);
502 case 0x9a: /* call absolute -- same as call absolute, indirect */
503 *tos
= orig_eip
+ (*tos
- copy_eip
);
506 if ((p
->ainsn
.insn
[1] & 0x30) == 0x10) {
508 * call absolute, indirect
509 * Fix return addr; eip is correct.
510 * But this is not boostable
512 *tos
= orig_eip
+ (*tos
- copy_eip
);
514 } else if (((p
->ainsn
.insn
[1] & 0x31) == 0x20) || /* jmp near, absolute indirect */
515 ((p
->ainsn
.insn
[1] & 0x31) == 0x21)) { /* jmp far, absolute indirect */
516 /* eip is correct. And this is boostable */
517 p
->ainsn
.boostable
= 1;
524 if (p
->ainsn
.boostable
== 0) {
525 if ((regs
->eip
> copy_eip
) &&
526 (regs
->eip
- copy_eip
) + 5 < MAX_INSN_SIZE
) {
528 * These instructions can be executed directly if it
529 * jumps back to correct address.
531 set_jmp_op((void *)regs
->eip
,
532 (void *)orig_eip
+ (regs
->eip
- copy_eip
));
533 p
->ainsn
.boostable
= 1;
535 p
->ainsn
.boostable
= -1;
539 regs
->eip
= orig_eip
+ (regs
->eip
- copy_eip
);
546 * Interrupts are disabled on entry as trap1 is an interrupt gate and they
547 * remain disabled thoroughout this function.
549 static int __kprobes
post_kprobe_handler(struct pt_regs
*regs
)
551 struct kprobe
*cur
= kprobe_running();
552 struct kprobe_ctlblk
*kcb
= get_kprobe_ctlblk();
557 if ((kcb
->kprobe_status
!= KPROBE_REENTER
) && cur
->post_handler
) {
558 kcb
->kprobe_status
= KPROBE_HIT_SSDONE
;
559 cur
->post_handler(cur
, regs
, 0);
562 resume_execution(cur
, regs
, kcb
);
563 regs
->eflags
|= kcb
->kprobe_saved_eflags
;
565 /*Restore back the original saved kprobes variables and continue. */
566 if (kcb
->kprobe_status
== KPROBE_REENTER
) {
567 restore_previous_kprobe(kcb
);
570 reset_current_kprobe();
572 preempt_enable_no_resched();
575 * if somebody else is singlestepping across a probe point, eflags
576 * will have TF set, in which case, continue the remaining processing
577 * of do_debug, as if this is not a probe hit.
579 if (regs
->eflags
& TF_MASK
)
585 static int __kprobes
kprobe_fault_handler(struct pt_regs
*regs
, int trapnr
)
587 struct kprobe
*cur
= kprobe_running();
588 struct kprobe_ctlblk
*kcb
= get_kprobe_ctlblk();
590 switch(kcb
->kprobe_status
) {
594 * We are here because the instruction being single
595 * stepped caused a page fault. We reset the current
596 * kprobe and the eip points back to the probe address
597 * and allow the page fault handler to continue as a
600 regs
->eip
= (unsigned long)cur
->addr
;
601 regs
->eflags
|= kcb
->kprobe_old_eflags
;
602 if (kcb
->kprobe_status
== KPROBE_REENTER
)
603 restore_previous_kprobe(kcb
);
605 reset_current_kprobe();
606 preempt_enable_no_resched();
608 case KPROBE_HIT_ACTIVE
:
609 case KPROBE_HIT_SSDONE
:
611 * We increment the nmissed count for accounting,
612 * we can also use npre/npostfault count for accouting
613 * these specific fault cases.
615 kprobes_inc_nmissed_count(cur
);
618 * We come here because instructions in the pre/post
619 * handler caused the page_fault, this could happen
620 * if handler tries to access user space by
621 * copy_from_user(), get_user() etc. Let the
622 * user-specified handler try to fix it first.
624 if (cur
->fault_handler
&& cur
->fault_handler(cur
, regs
, trapnr
))
628 * In case the user-specified fault handler returned
629 * zero, try to fix up.
631 if (fixup_exception(regs
))
635 * fixup_exception() could not handle it,
636 * Let do_page_fault() fix it.
646 * Wrapper routine to for handling exceptions.
648 int __kprobes
kprobe_exceptions_notify(struct notifier_block
*self
,
649 unsigned long val
, void *data
)
651 struct die_args
*args
= (struct die_args
*)data
;
652 int ret
= NOTIFY_DONE
;
654 if (args
->regs
&& user_mode_vm(args
->regs
))
659 if (kprobe_handler(args
->regs
))
663 if (post_kprobe_handler(args
->regs
))
668 /* kprobe_running() needs smp_processor_id() */
670 if (kprobe_running() &&
671 kprobe_fault_handler(args
->regs
, args
->trapnr
))
681 int __kprobes
setjmp_pre_handler(struct kprobe
*p
, struct pt_regs
*regs
)
683 struct jprobe
*jp
= container_of(p
, struct jprobe
, kp
);
685 struct kprobe_ctlblk
*kcb
= get_kprobe_ctlblk();
687 kcb
->jprobe_saved_regs
= *regs
;
688 kcb
->jprobe_saved_esp
= ®s
->esp
;
689 addr
= (unsigned long)(kcb
->jprobe_saved_esp
);
692 * TBD: As Linus pointed out, gcc assumes that the callee
693 * owns the argument space and could overwrite it, e.g.
694 * tailcall optimization. So, to be absolutely safe
695 * we also save and restore enough stack bytes to cover
698 memcpy(kcb
->jprobes_stack
, (kprobe_opcode_t
*)addr
,
699 MIN_STACK_SIZE(addr
));
700 regs
->eflags
&= ~IF_MASK
;
701 regs
->eip
= (unsigned long)(jp
->entry
);
705 void __kprobes
jprobe_return(void)
707 struct kprobe_ctlblk
*kcb
= get_kprobe_ctlblk();
709 asm volatile (" xchgl %%ebx,%%esp \n"
711 " .globl jprobe_return_end \n"
712 " jprobe_return_end: \n"
714 (kcb
->jprobe_saved_esp
):"memory");
717 int __kprobes
longjmp_break_handler(struct kprobe
*p
, struct pt_regs
*regs
)
719 struct kprobe_ctlblk
*kcb
= get_kprobe_ctlblk();
720 u8
*addr
= (u8
*) (regs
->eip
- 1);
721 unsigned long stack_addr
= (unsigned long)(kcb
->jprobe_saved_esp
);
722 struct jprobe
*jp
= container_of(p
, struct jprobe
, kp
);
724 if ((addr
> (u8
*) jprobe_return
) && (addr
< (u8
*) jprobe_return_end
)) {
725 if (®s
->esp
!= kcb
->jprobe_saved_esp
) {
726 struct pt_regs
*saved_regs
=
727 container_of(kcb
->jprobe_saved_esp
,
728 struct pt_regs
, esp
);
729 printk("current esp %p does not match saved esp %p\n",
730 ®s
->esp
, kcb
->jprobe_saved_esp
);
731 printk("Saved registers for jprobe %p\n", jp
);
732 show_registers(saved_regs
);
733 printk("Current registers\n");
734 show_registers(regs
);
737 *regs
= kcb
->jprobe_saved_regs
;
738 memcpy((kprobe_opcode_t
*) stack_addr
, kcb
->jprobes_stack
,
739 MIN_STACK_SIZE(stack_addr
));
740 preempt_enable_no_resched();
746 int __init
arch_init_kprobes(void)