2 * Kernel Probes (KProbes)
3 * arch/x86_64/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 * 2004-Oct Jim Keniston <kenistoj@us.ibm.com> and Prasanna S Panchamukhi
27 * <prasanna@in.ibm.com> adapted for x86_64
28 * 2005-Mar Roland McGrath <roland@redhat.com>
29 * Fixed to handle %rip-relative addressing mode correctly.
30 * 2005-May Rusty Lynch <rusty.lynch@intel.com>
31 * Added function return probes functionality
34 #include <linux/config.h>
35 #include <linux/kprobes.h>
36 #include <linux/ptrace.h>
37 #include <linux/string.h>
38 #include <linux/slab.h>
39 #include <linux/preempt.h>
41 #include <asm/cacheflush.h>
42 #include <asm/pgtable.h>
43 #include <asm/kdebug.h>
45 static DECLARE_MUTEX(kprobe_mutex
);
46 void jprobe_return_end(void);
48 DEFINE_PER_CPU(struct kprobe
*, current_kprobe
) = NULL
;
49 DEFINE_PER_CPU(struct kprobe_ctlblk
, kprobe_ctlblk
);
52 * returns non-zero if opcode modifies the interrupt flag.
54 static inline int is_IF_modifier(kprobe_opcode_t
*insn
)
59 case 0xcf: /* iret/iretd */
60 case 0x9d: /* popf/popfd */
64 if (*insn
>= 0x40 && *insn
<= 0x4f && *++insn
== 0xcf)
69 int __kprobes
arch_prepare_kprobe(struct kprobe
*p
)
71 /* insn: must be on special executable page on x86_64. */
73 p
->ainsn
.insn
= get_insn_slot();
82 * Determine if the instruction uses the %rip-relative addressing mode.
83 * If it does, return the address of the 32-bit displacement word.
84 * If not, return null.
86 static inline s32
*is_riprel(u8
*insn
)
88 #define W(row,b0,b1,b2,b3,b4,b5,b6,b7,b8,b9,ba,bb,bc,bd,be,bf) \
89 (((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \
90 (b4##UL << 0x4)|(b5##UL << 0x5)|(b6##UL << 0x6)|(b7##UL << 0x7) | \
91 (b8##UL << 0x8)|(b9##UL << 0x9)|(ba##UL << 0xa)|(bb##UL << 0xb) | \
92 (bc##UL << 0xc)|(bd##UL << 0xd)|(be##UL << 0xe)|(bf##UL << 0xf)) \
94 static const u64 onebyte_has_modrm
[256 / 64] = {
95 /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
96 /* ------------------------------- */
97 W(0x00, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0)| /* 00 */
98 W(0x10, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0)| /* 10 */
99 W(0x20, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0)| /* 20 */
100 W(0x30, 1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0), /* 30 */
101 W(0x40, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 40 */
102 W(0x50, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 50 */
103 W(0x60, 0,0,1,1,0,0,0,0,0,1,0,1,0,0,0,0)| /* 60 */
104 W(0x70, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 70 */
105 W(0x80, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 80 */
106 W(0x90, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 90 */
107 W(0xa0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* a0 */
108 W(0xb0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* b0 */
109 W(0xc0, 1,1,0,0,1,1,1,1,0,0,0,0,0,0,0,0)| /* c0 */
110 W(0xd0, 1,1,1,1,0,0,0,0,1,1,1,1,1,1,1,1)| /* d0 */
111 W(0xe0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* e0 */
112 W(0xf0, 0,0,0,0,0,0,1,1,0,0,0,0,0,0,1,1) /* f0 */
113 /* ------------------------------- */
114 /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
116 static const u64 twobyte_has_modrm
[256 / 64] = {
117 /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
118 /* ------------------------------- */
119 W(0x00, 1,1,1,1,0,0,0,0,0,0,0,0,0,1,0,1)| /* 0f */
120 W(0x10, 1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0)| /* 1f */
121 W(0x20, 1,1,1,1,1,0,1,0,1,1,1,1,1,1,1,1)| /* 2f */
122 W(0x30, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 3f */
123 W(0x40, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 4f */
124 W(0x50, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 5f */
125 W(0x60, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 6f */
126 W(0x70, 1,1,1,1,1,1,1,0,0,0,0,0,1,1,1,1), /* 7f */
127 W(0x80, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 8f */
128 W(0x90, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 9f */
129 W(0xa0, 0,0,0,1,1,1,1,1,0,0,0,1,1,1,1,1)| /* af */
130 W(0xb0, 1,1,1,1,1,1,1,1,0,0,1,1,1,1,1,1), /* bf */
131 W(0xc0, 1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0)| /* cf */
132 W(0xd0, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* df */
133 W(0xe0, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* ef */
134 W(0xf0, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0) /* ff */
135 /* ------------------------------- */
136 /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
141 /* Skip legacy instruction prefixes. */
161 /* Skip REX instruction prefix. */
162 if ((*insn
& 0xf0) == 0x40)
165 if (*insn
== 0x0f) { /* Two-byte opcode. */
167 need_modrm
= test_bit(*insn
, twobyte_has_modrm
);
168 } else { /* One-byte opcode. */
169 need_modrm
= test_bit(*insn
, onebyte_has_modrm
);
174 if ((modrm
& 0xc7) == 0x05) { /* %rip+disp32 addressing mode */
175 /* Displacement follows ModRM byte. */
176 return (s32
*) ++insn
;
180 /* No %rip-relative addressing mode here. */
184 void __kprobes
arch_copy_kprobe(struct kprobe
*p
)
187 memcpy(p
->ainsn
.insn
, p
->addr
, MAX_INSN_SIZE
);
188 ripdisp
= is_riprel(p
->ainsn
.insn
);
191 * The copied instruction uses the %rip-relative
192 * addressing mode. Adjust the displacement for the
193 * difference between the original location of this
194 * instruction and the location of the copy that will
195 * actually be run. The tricky bit here is making sure
196 * that the sign extension happens correctly in this
197 * calculation, since we need a signed 32-bit result to
198 * be sign-extended to 64 bits when it's added to the
199 * %rip value and yield the same 64-bit result that the
200 * sign-extension of the original signed 32-bit
201 * displacement would have given.
203 s64 disp
= (u8
*) p
->addr
+ *ripdisp
- (u8
*) p
->ainsn
.insn
;
204 BUG_ON((s64
) (s32
) disp
!= disp
); /* Sanity check. */
207 p
->opcode
= *p
->addr
;
210 void __kprobes
arch_arm_kprobe(struct kprobe
*p
)
212 *p
->addr
= BREAKPOINT_INSTRUCTION
;
213 flush_icache_range((unsigned long) p
->addr
,
214 (unsigned long) p
->addr
+ sizeof(kprobe_opcode_t
));
217 void __kprobes
arch_disarm_kprobe(struct kprobe
*p
)
219 *p
->addr
= p
->opcode
;
220 flush_icache_range((unsigned long) p
->addr
,
221 (unsigned long) p
->addr
+ sizeof(kprobe_opcode_t
));
224 void __kprobes
arch_remove_kprobe(struct kprobe
*p
)
227 free_insn_slot(p
->ainsn
.insn
);
231 static inline void save_previous_kprobe(struct kprobe_ctlblk
*kcb
)
233 kcb
->prev_kprobe
.kp
= kprobe_running();
234 kcb
->prev_kprobe
.status
= kcb
->kprobe_status
;
235 kcb
->prev_kprobe
.old_rflags
= kcb
->kprobe_old_rflags
;
236 kcb
->prev_kprobe
.saved_rflags
= kcb
->kprobe_saved_rflags
;
239 static inline void restore_previous_kprobe(struct kprobe_ctlblk
*kcb
)
241 __get_cpu_var(current_kprobe
) = kcb
->prev_kprobe
.kp
;
242 kcb
->kprobe_status
= kcb
->prev_kprobe
.status
;
243 kcb
->kprobe_old_rflags
= kcb
->prev_kprobe
.old_rflags
;
244 kcb
->kprobe_saved_rflags
= kcb
->prev_kprobe
.saved_rflags
;
247 static inline void set_current_kprobe(struct kprobe
*p
, struct pt_regs
*regs
,
248 struct kprobe_ctlblk
*kcb
)
250 __get_cpu_var(current_kprobe
) = p
;
251 kcb
->kprobe_saved_rflags
= kcb
->kprobe_old_rflags
252 = (regs
->eflags
& (TF_MASK
| IF_MASK
));
253 if (is_IF_modifier(p
->ainsn
.insn
))
254 kcb
->kprobe_saved_rflags
&= ~IF_MASK
;
257 static void __kprobes
prepare_singlestep(struct kprobe
*p
, struct pt_regs
*regs
)
259 regs
->eflags
|= TF_MASK
;
260 regs
->eflags
&= ~IF_MASK
;
261 /*single step inline if the instruction is an int3*/
262 if (p
->opcode
== BREAKPOINT_INSTRUCTION
)
263 regs
->rip
= (unsigned long)p
->addr
;
265 regs
->rip
= (unsigned long)p
->ainsn
.insn
;
268 /* Called with kretprobe_lock held */
269 void __kprobes
arch_prepare_kretprobe(struct kretprobe
*rp
,
270 struct pt_regs
*regs
)
272 unsigned long *sara
= (unsigned long *)regs
->rsp
;
273 struct kretprobe_instance
*ri
;
275 if ((ri
= get_free_rp_inst(rp
)) != NULL
) {
278 ri
->ret_addr
= (kprobe_opcode_t
*) *sara
;
280 /* Replace the return addr with trampoline addr */
281 *sara
= (unsigned long) &kretprobe_trampoline
;
289 int __kprobes
kprobe_handler(struct pt_regs
*regs
)
293 kprobe_opcode_t
*addr
= (kprobe_opcode_t
*)(regs
->rip
- sizeof(kprobe_opcode_t
));
294 struct kprobe_ctlblk
*kcb
;
297 * We don't want to be preempted for the entire
298 * duration of kprobe processing
301 kcb
= get_kprobe_ctlblk();
303 /* Check we're not actually recursing */
304 if (kprobe_running()) {
305 p
= get_kprobe(addr
);
307 if (kcb
->kprobe_status
== KPROBE_HIT_SS
&&
308 *p
->ainsn
.insn
== BREAKPOINT_INSTRUCTION
) {
309 regs
->eflags
&= ~TF_MASK
;
310 regs
->eflags
|= kcb
->kprobe_saved_rflags
;
312 } else if (kcb
->kprobe_status
== KPROBE_HIT_SSDONE
) {
313 /* TODO: Provide re-entrancy from
314 * post_kprobes_handler() and avoid exception
315 * stack corruption while single-stepping on
316 * the instruction of the new probe.
318 arch_disarm_kprobe(p
);
319 regs
->rip
= (unsigned long)p
->addr
;
320 reset_current_kprobe();
323 /* We have reentered the kprobe_handler(), since
324 * another probe was hit while within the
325 * handler. We here save the original kprobe
326 * variables and just single step on instruction
327 * of the new probe without calling any user
330 save_previous_kprobe(kcb
);
331 set_current_kprobe(p
, regs
, kcb
);
332 kprobes_inc_nmissed_count(p
);
333 prepare_singlestep(p
, regs
);
334 kcb
->kprobe_status
= KPROBE_REENTER
;
338 p
= __get_cpu_var(current_kprobe
);
339 if (p
->break_handler
&& p
->break_handler(p
, regs
)) {
346 p
= get_kprobe(addr
);
348 if (*addr
!= BREAKPOINT_INSTRUCTION
) {
350 * The breakpoint instruction was removed right
351 * after we hit it. Another cpu has removed
352 * either a probepoint or a debugger breakpoint
353 * at this address. In either case, no further
354 * handling of this interrupt is appropriate.
355 * Back up over the (now missing) int3 and run
356 * the original instruction.
358 regs
->rip
= (unsigned long)addr
;
361 /* Not one of ours: let kernel handle it */
365 set_current_kprobe(p
, regs
, kcb
);
366 kcb
->kprobe_status
= KPROBE_HIT_ACTIVE
;
368 if (p
->pre_handler
&& p
->pre_handler(p
, regs
))
369 /* handler has already set things up, so skip ss setup */
373 prepare_singlestep(p
, regs
);
374 kcb
->kprobe_status
= KPROBE_HIT_SS
;
378 preempt_enable_no_resched();
383 * For function-return probes, init_kprobes() establishes a probepoint
384 * here. When a retprobed function returns, this probe is hit and
385 * trampoline_probe_handler() runs, calling the kretprobe's handler.
387 void kretprobe_trampoline_holder(void)
389 asm volatile ( ".global kretprobe_trampoline\n"
390 "kretprobe_trampoline: \n"
395 * Called when we hit the probe point at kretprobe_trampoline
397 int __kprobes
trampoline_probe_handler(struct kprobe
*p
, struct pt_regs
*regs
)
399 struct kretprobe_instance
*ri
= NULL
;
400 struct hlist_head
*head
;
401 struct hlist_node
*node
, *tmp
;
402 unsigned long flags
, orig_ret_address
= 0;
403 unsigned long trampoline_address
=(unsigned long)&kretprobe_trampoline
;
405 spin_lock_irqsave(&kretprobe_lock
, flags
);
406 head
= kretprobe_inst_table_head(current
);
409 * It is possible to have multiple instances associated with a given
410 * task either because an multiple functions in the call path
411 * have a return probe installed on them, and/or more then one return
412 * return probe was registered for a target function.
414 * We can handle this because:
415 * - instances are always inserted at the head of the list
416 * - when multiple return probes are registered for the same
417 * function, the first instance's ret_addr will point to the
418 * real return address, and all the rest will point to
419 * kretprobe_trampoline
421 hlist_for_each_entry_safe(ri
, node
, tmp
, head
, hlist
) {
422 if (ri
->task
!= current
)
423 /* another task is sharing our hash bucket */
426 if (ri
->rp
&& ri
->rp
->handler
)
427 ri
->rp
->handler(ri
, regs
);
429 orig_ret_address
= (unsigned long)ri
->ret_addr
;
432 if (orig_ret_address
!= trampoline_address
)
434 * This is the real return address. Any other
435 * instances associated with this task are for
436 * other calls deeper on the call stack
441 BUG_ON(!orig_ret_address
|| (orig_ret_address
== trampoline_address
));
442 regs
->rip
= orig_ret_address
;
444 reset_current_kprobe();
445 spin_unlock_irqrestore(&kretprobe_lock
, flags
);
446 preempt_enable_no_resched();
449 * By returning a non-zero value, we are telling
450 * kprobe_handler() that we don't want the post_handler
451 * to run (and have re-enabled preemption)
457 * Called after single-stepping. p->addr is the address of the
458 * instruction whose first byte has been replaced by the "int 3"
459 * instruction. To avoid the SMP problems that can occur when we
460 * temporarily put back the original opcode to single-step, we
461 * single-stepped a copy of the instruction. The address of this
462 * copy is p->ainsn.insn.
464 * This function prepares to return from the post-single-step
465 * interrupt. We have to fix up the stack as follows:
467 * 0) Except in the case of absolute or indirect jump or call instructions,
468 * the new rip is relative to the copied instruction. We need to make
469 * it relative to the original instruction.
471 * 1) If the single-stepped instruction was pushfl, then the TF and IF
472 * flags are set in the just-pushed eflags, and may need to be cleared.
474 * 2) If the single-stepped instruction was a call, the return address
475 * that is atop the stack is the address following the copied instruction.
476 * We need to make it the address following the original instruction.
478 static void __kprobes
resume_execution(struct kprobe
*p
,
479 struct pt_regs
*regs
, struct kprobe_ctlblk
*kcb
)
481 unsigned long *tos
= (unsigned long *)regs
->rsp
;
482 unsigned long next_rip
= 0;
483 unsigned long copy_rip
= (unsigned long)p
->ainsn
.insn
;
484 unsigned long orig_rip
= (unsigned long)p
->addr
;
485 kprobe_opcode_t
*insn
= p
->ainsn
.insn
;
487 /*skip the REX prefix*/
488 if (*insn
>= 0x40 && *insn
<= 0x4f)
492 case 0x9c: /* pushfl */
493 *tos
&= ~(TF_MASK
| IF_MASK
);
494 *tos
|= kcb
->kprobe_old_rflags
;
496 case 0xc3: /* ret/lret */
500 regs
->eflags
&= ~TF_MASK
;
501 /* rip is already adjusted, no more changes required*/
503 case 0xe8: /* call relative - Fix return addr */
504 *tos
= orig_rip
+ (*tos
- copy_rip
);
507 if ((*insn
& 0x30) == 0x10) {
508 /* call absolute, indirect */
509 /* Fix return addr; rip is correct. */
510 next_rip
= regs
->rip
;
511 *tos
= orig_rip
+ (*tos
- copy_rip
);
512 } else if (((*insn
& 0x31) == 0x20) || /* jmp near, absolute indirect */
513 ((*insn
& 0x31) == 0x21)) { /* jmp far, absolute indirect */
514 /* rip is correct. */
515 next_rip
= regs
->rip
;
518 case 0xea: /* jmp absolute -- rip is correct */
519 next_rip
= regs
->rip
;
525 regs
->eflags
&= ~TF_MASK
;
527 regs
->rip
= next_rip
;
529 regs
->rip
= orig_rip
+ (regs
->rip
- copy_rip
);
533 int __kprobes
post_kprobe_handler(struct pt_regs
*regs
)
535 struct kprobe
*cur
= kprobe_running();
536 struct kprobe_ctlblk
*kcb
= get_kprobe_ctlblk();
541 if ((kcb
->kprobe_status
!= KPROBE_REENTER
) && cur
->post_handler
) {
542 kcb
->kprobe_status
= KPROBE_HIT_SSDONE
;
543 cur
->post_handler(cur
, regs
, 0);
546 resume_execution(cur
, regs
, kcb
);
547 regs
->eflags
|= kcb
->kprobe_saved_rflags
;
549 /* Restore the original saved kprobes variables and continue. */
550 if (kcb
->kprobe_status
== KPROBE_REENTER
) {
551 restore_previous_kprobe(kcb
);
554 reset_current_kprobe();
556 preempt_enable_no_resched();
559 * if somebody else is singlestepping across a probe point, eflags
560 * will have TF set, in which case, continue the remaining processing
561 * of do_debug, as if this is not a probe hit.
563 if (regs
->eflags
& TF_MASK
)
569 int __kprobes
kprobe_fault_handler(struct pt_regs
*regs
, int trapnr
)
571 struct kprobe
*cur
= kprobe_running();
572 struct kprobe_ctlblk
*kcb
= get_kprobe_ctlblk();
574 if (cur
->fault_handler
&& cur
->fault_handler(cur
, regs
, trapnr
))
577 if (kcb
->kprobe_status
& KPROBE_HIT_SS
) {
578 resume_execution(cur
, regs
, kcb
);
579 regs
->eflags
|= kcb
->kprobe_old_rflags
;
581 reset_current_kprobe();
582 preempt_enable_no_resched();
588 * Wrapper routine for handling exceptions.
590 int __kprobes
kprobe_exceptions_notify(struct notifier_block
*self
,
591 unsigned long val
, void *data
)
593 struct die_args
*args
= (struct die_args
*)data
;
594 int ret
= NOTIFY_DONE
;
598 if (kprobe_handler(args
->regs
))
602 if (post_kprobe_handler(args
->regs
))
607 /* kprobe_running() needs smp_processor_id() */
609 if (kprobe_running() &&
610 kprobe_fault_handler(args
->regs
, args
->trapnr
))
620 int __kprobes
setjmp_pre_handler(struct kprobe
*p
, struct pt_regs
*regs
)
622 struct jprobe
*jp
= container_of(p
, struct jprobe
, kp
);
624 struct kprobe_ctlblk
*kcb
= get_kprobe_ctlblk();
626 kcb
->jprobe_saved_regs
= *regs
;
627 kcb
->jprobe_saved_rsp
= (long *) regs
->rsp
;
628 addr
= (unsigned long)(kcb
->jprobe_saved_rsp
);
630 * As Linus pointed out, gcc assumes that the callee
631 * owns the argument space and could overwrite it, e.g.
632 * tailcall optimization. So, to be absolutely safe
633 * we also save and restore enough stack bytes to cover
636 memcpy(kcb
->jprobes_stack
, (kprobe_opcode_t
*)addr
,
637 MIN_STACK_SIZE(addr
));
638 regs
->eflags
&= ~IF_MASK
;
639 regs
->rip
= (unsigned long)(jp
->entry
);
643 void __kprobes
jprobe_return(void)
645 struct kprobe_ctlblk
*kcb
= get_kprobe_ctlblk();
647 asm volatile (" xchg %%rbx,%%rsp \n"
649 " .globl jprobe_return_end \n"
650 " jprobe_return_end: \n"
652 (kcb
->jprobe_saved_rsp
):"memory");
655 int __kprobes
longjmp_break_handler(struct kprobe
*p
, struct pt_regs
*regs
)
657 struct kprobe_ctlblk
*kcb
= get_kprobe_ctlblk();
658 u8
*addr
= (u8
*) (regs
->rip
- 1);
659 unsigned long stack_addr
= (unsigned long)(kcb
->jprobe_saved_rsp
);
660 struct jprobe
*jp
= container_of(p
, struct jprobe
, kp
);
662 if ((addr
> (u8
*) jprobe_return
) && (addr
< (u8
*) jprobe_return_end
)) {
663 if ((long *)regs
->rsp
!= kcb
->jprobe_saved_rsp
) {
664 struct pt_regs
*saved_regs
=
665 container_of(kcb
->jprobe_saved_rsp
,
666 struct pt_regs
, rsp
);
667 printk("current rsp %p does not match saved rsp %p\n",
668 (long *)regs
->rsp
, kcb
->jprobe_saved_rsp
);
669 printk("Saved registers for jprobe %p\n", jp
);
670 show_registers(saved_regs
);
671 printk("Current registers\n");
672 show_registers(regs
);
675 *regs
= kcb
->jprobe_saved_regs
;
676 memcpy((kprobe_opcode_t
*) stack_addr
, kcb
->jprobes_stack
,
677 MIN_STACK_SIZE(stack_addr
));
678 preempt_enable_no_resched();
684 static struct kprobe trampoline_p
= {
685 .addr
= (kprobe_opcode_t
*) &kretprobe_trampoline
,
686 .pre_handler
= trampoline_probe_handler
689 int __init
arch_init_kprobes(void)
691 return register_kprobe(&trampoline_p
);