2 * Kernel Probes (KProbes)
3 * arch/ia64/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
20 * Copyright (C) Intel Corporation, 2005
22 * 2005-Apr Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy
23 * <anil.s.keshavamurthy@intel.com> adapted from i386
26 #include <linux/config.h>
27 #include <linux/kprobes.h>
28 #include <linux/ptrace.h>
29 #include <linux/string.h>
30 #include <linux/slab.h>
31 #include <linux/preempt.h>
32 #include <linux/moduleloader.h>
34 #include <asm/pgtable.h>
35 #include <asm/kdebug.h>
36 #include <asm/sections.h>
38 extern void jprobe_inst_return(void);
40 DEFINE_PER_CPU(struct kprobe
*, current_kprobe
) = NULL
;
41 DEFINE_PER_CPU(struct kprobe_ctlblk
, kprobe_ctlblk
);
43 enum instruction_type
{A
, I
, M
, F
, B
, L
, X
, u
};
44 static enum instruction_type bundle_encoding
[32][3] = {
80 * In this function we check to see if the instruction
81 * is IP relative instruction and update the kprobe
82 * inst flag accordingly
84 static void __kprobes
update_kprobe_inst_flag(uint
template, uint slot
,
86 unsigned long kprobe_inst
,
89 p
->ainsn
.inst_flag
= 0;
90 p
->ainsn
.target_br_reg
= 0;
92 /* Check for Break instruction
93 * Bits 37:40 Major opcode to be zero
94 * Bits 27:32 X6 to be zero
95 * Bits 32:35 X3 to be zero
97 if ((!major_opcode
) && (!((kprobe_inst
>> 27) & 0x1FF)) ) {
98 /* is a break instruction */
99 p
->ainsn
.inst_flag
|= INST_FLAG_BREAK_INST
;
103 if (bundle_encoding
[template][slot
] == B
) {
104 switch (major_opcode
) {
105 case INDIRECT_CALL_OPCODE
:
106 p
->ainsn
.inst_flag
|= INST_FLAG_FIX_BRANCH_REG
;
107 p
->ainsn
.target_br_reg
= ((kprobe_inst
>> 6) & 0x7);
109 case IP_RELATIVE_PREDICT_OPCODE
:
110 case IP_RELATIVE_BRANCH_OPCODE
:
111 p
->ainsn
.inst_flag
|= INST_FLAG_FIX_RELATIVE_IP_ADDR
;
113 case IP_RELATIVE_CALL_OPCODE
:
114 p
->ainsn
.inst_flag
|= INST_FLAG_FIX_RELATIVE_IP_ADDR
;
115 p
->ainsn
.inst_flag
|= INST_FLAG_FIX_BRANCH_REG
;
116 p
->ainsn
.target_br_reg
= ((kprobe_inst
>> 6) & 0x7);
119 } else if (bundle_encoding
[template][slot
] == X
) {
120 switch (major_opcode
) {
121 case LONG_CALL_OPCODE
:
122 p
->ainsn
.inst_flag
|= INST_FLAG_FIX_BRANCH_REG
;
123 p
->ainsn
.target_br_reg
= ((kprobe_inst
>> 6) & 0x7);
131 * In this function we check to see if the instruction
132 * on which we are inserting kprobe is supported.
133 * Returns 0 if supported
134 * Returns -EINVAL if unsupported
136 static int __kprobes
unsupported_inst(uint
template, uint slot
,
138 unsigned long kprobe_inst
,
141 unsigned long addr
= (unsigned long)p
->addr
;
143 if (bundle_encoding
[template][slot
] == I
) {
144 switch (major_opcode
) {
145 case 0x0: //I_UNIT_MISC_OPCODE:
147 * Check for Integer speculation instruction
148 * - Bit 33-35 to be equal to 0x1
150 if (((kprobe_inst
>> 33) & 0x7) == 1) {
152 "Kprobes on speculation inst at <0x%lx> not supported\n",
158 * IP relative mov instruction
159 * - Bit 27-35 to be equal to 0x30
161 if (((kprobe_inst
>> 27) & 0x1FF) == 0x30) {
163 "Kprobes on \"mov r1=ip\" at <0x%lx> not supported\n",
175 * In this function we check to see if the instruction
176 * (qp) cmpx.crel.ctype p1,p2=r2,r3
177 * on which we are inserting kprobe is cmp instruction
180 static uint __kprobes
is_cmp_ctype_unc_inst(uint
template, uint slot
,
182 unsigned long kprobe_inst
)
187 if (!((bundle_encoding
[template][slot
] == I
) ||
188 (bundle_encoding
[template][slot
] == M
)))
191 if (!((major_opcode
== 0xC) || (major_opcode
== 0xD) ||
192 (major_opcode
== 0xE)))
195 cmp_inst
.l
= kprobe_inst
;
196 if ((cmp_inst
.f
.x2
== 0) || (cmp_inst
.f
.x2
== 1)) {
197 /* Integere compare - Register Register (A6 type)*/
198 if ((cmp_inst
.f
.tb
== 0) && (cmp_inst
.f
.ta
== 0)
199 &&(cmp_inst
.f
.c
== 1))
201 } else if ((cmp_inst
.f
.x2
== 2)||(cmp_inst
.f
.x2
== 3)) {
202 /* Integere compare - Immediate Register (A8 type)*/
203 if ((cmp_inst
.f
.ta
== 0) &&(cmp_inst
.f
.c
== 1))
211 * In this function we override the bundle with
212 * the break instruction at the given slot.
214 static void __kprobes
prepare_break_inst(uint
template, uint slot
,
216 unsigned long kprobe_inst
,
219 unsigned long break_inst
= BREAK_INST
;
220 bundle_t
*bundle
= &p
->ainsn
.insn
.bundle
;
223 * Copy the original kprobe_inst qualifying predicate(qp)
224 * to the break instruction iff !is_cmp_ctype_unc_inst
225 * because for cmp instruction with ctype equal to unc,
226 * which is a special instruction always needs to be
227 * executed regradless of qp
229 if (!is_cmp_ctype_unc_inst(template, slot
, major_opcode
, kprobe_inst
))
230 break_inst
|= (0x3f & kprobe_inst
);
234 bundle
->quad0
.slot0
= break_inst
;
237 bundle
->quad0
.slot1_p0
= break_inst
;
238 bundle
->quad1
.slot1_p1
= break_inst
>> (64-46);
241 bundle
->quad1
.slot2
= break_inst
;
246 * Update the instruction flag, so that we can
247 * emulate the instruction properly after we
248 * single step on original instruction
250 update_kprobe_inst_flag(template, slot
, major_opcode
, kprobe_inst
, p
);
253 static inline void get_kprobe_inst(bundle_t
*bundle
, uint slot
,
254 unsigned long *kprobe_inst
, uint
*major_opcode
)
256 unsigned long kprobe_inst_p0
, kprobe_inst_p1
;
257 unsigned int template;
259 template = bundle
->quad0
.template;
263 *major_opcode
= (bundle
->quad0
.slot0
>> SLOT0_OPCODE_SHIFT
);
264 *kprobe_inst
= bundle
->quad0
.slot0
;
267 *major_opcode
= (bundle
->quad1
.slot1_p1
>> SLOT1_p1_OPCODE_SHIFT
);
268 kprobe_inst_p0
= bundle
->quad0
.slot1_p0
;
269 kprobe_inst_p1
= bundle
->quad1
.slot1_p1
;
270 *kprobe_inst
= kprobe_inst_p0
| (kprobe_inst_p1
<< (64-46));
273 *major_opcode
= (bundle
->quad1
.slot2
>> SLOT2_OPCODE_SHIFT
);
274 *kprobe_inst
= bundle
->quad1
.slot2
;
279 /* Returns non-zero if the addr is in the Interrupt Vector Table */
280 static inline int in_ivt_functions(unsigned long addr
)
282 return (addr
>= (unsigned long)__start_ivt_text
283 && addr
< (unsigned long)__end_ivt_text
);
286 static int __kprobes
valid_kprobe_addr(int template, int slot
,
289 if ((slot
> 2) || ((bundle_encoding
[template][1] == L
) && slot
> 1)) {
290 printk(KERN_WARNING
"Attempting to insert unaligned kprobe "
295 if (in_ivt_functions(addr
)) {
296 printk(KERN_WARNING
"Kprobes can't be inserted inside "
297 "IVT functions at 0x%lx\n", addr
);
301 if (slot
== 1 && bundle_encoding
[template][1] != L
) {
302 printk(KERN_WARNING
"Inserting kprobes on slot #1 "
303 "is not supported\n");
310 static inline void save_previous_kprobe(struct kprobe_ctlblk
*kcb
)
312 kcb
->prev_kprobe
.kp
= kprobe_running();
313 kcb
->prev_kprobe
.status
= kcb
->kprobe_status
;
316 static inline void restore_previous_kprobe(struct kprobe_ctlblk
*kcb
)
318 __get_cpu_var(current_kprobe
) = kcb
->prev_kprobe
.kp
;
319 kcb
->kprobe_status
= kcb
->prev_kprobe
.status
;
322 static inline void set_current_kprobe(struct kprobe
*p
,
323 struct kprobe_ctlblk
*kcb
)
325 __get_cpu_var(current_kprobe
) = p
;
328 static void kretprobe_trampoline(void)
333 * At this point the target function has been tricked into
334 * returning into our trampoline. Lookup the associated instance
336 * - call the handler function
337 * - cleanup by marking the instance as unused
338 * - long jump back to the original return address
340 int __kprobes
trampoline_probe_handler(struct kprobe
*p
, struct pt_regs
*regs
)
342 struct kretprobe_instance
*ri
= NULL
;
343 struct hlist_head
*head
;
344 struct hlist_node
*node
, *tmp
;
345 unsigned long flags
, orig_ret_address
= 0;
346 unsigned long trampoline_address
=
347 ((struct fnptr
*)kretprobe_trampoline
)->ip
;
349 spin_lock_irqsave(&kretprobe_lock
, flags
);
350 head
= kretprobe_inst_table_head(current
);
353 * It is possible to have multiple instances associated with a given
354 * task either because an multiple functions in the call path
355 * have a return probe installed on them, and/or more then one return
356 * return probe was registered for a target function.
358 * We can handle this because:
359 * - instances are always inserted at the head of the list
360 * - when multiple return probes are registered for the same
361 * function, the first instance's ret_addr will point to the
362 * real return address, and all the rest will point to
363 * kretprobe_trampoline
365 hlist_for_each_entry_safe(ri
, node
, tmp
, head
, hlist
) {
366 if (ri
->task
!= current
)
367 /* another task is sharing our hash bucket */
370 if (ri
->rp
&& ri
->rp
->handler
)
371 ri
->rp
->handler(ri
, regs
);
373 orig_ret_address
= (unsigned long)ri
->ret_addr
;
376 if (orig_ret_address
!= trampoline_address
)
378 * This is the real return address. Any other
379 * instances associated with this task are for
380 * other calls deeper on the call stack
385 BUG_ON(!orig_ret_address
|| (orig_ret_address
== trampoline_address
));
386 regs
->cr_iip
= orig_ret_address
;
388 reset_current_kprobe();
389 spin_unlock_irqrestore(&kretprobe_lock
, flags
);
390 preempt_enable_no_resched();
393 * By returning a non-zero value, we are telling
394 * kprobe_handler() that we don't want the post_handler
395 * to run (and have re-enabled preemption)
400 /* Called with kretprobe_lock held */
401 void __kprobes
arch_prepare_kretprobe(struct kretprobe
*rp
,
402 struct pt_regs
*regs
)
404 struct kretprobe_instance
*ri
;
406 if ((ri
= get_free_rp_inst(rp
)) != NULL
) {
409 ri
->ret_addr
= (kprobe_opcode_t
*)regs
->b0
;
411 /* Replace the return addr with trampoline addr */
412 regs
->b0
= ((struct fnptr
*)kretprobe_trampoline
)->ip
;
420 int __kprobes
arch_prepare_kprobe(struct kprobe
*p
)
422 unsigned long addr
= (unsigned long) p
->addr
;
423 unsigned long *kprobe_addr
= (unsigned long *)(addr
& ~0xFULL
);
424 unsigned long kprobe_inst
=0;
425 unsigned int slot
= addr
& 0xf, template, major_opcode
= 0;
426 bundle_t
*bundle
= &p
->ainsn
.insn
.bundle
;
428 memcpy(&p
->opcode
.bundle
, kprobe_addr
, sizeof(bundle_t
));
429 memcpy(&p
->ainsn
.insn
.bundle
, kprobe_addr
, sizeof(bundle_t
));
431 template = bundle
->quad0
.template;
433 if(valid_kprobe_addr(template, slot
, addr
))
436 /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
437 if (slot
== 1 && bundle_encoding
[template][1] == L
)
440 /* Get kprobe_inst and major_opcode from the bundle */
441 get_kprobe_inst(bundle
, slot
, &kprobe_inst
, &major_opcode
);
443 if (unsupported_inst(template, slot
, major_opcode
, kprobe_inst
, p
))
446 prepare_break_inst(template, slot
, major_opcode
, kprobe_inst
, p
);
451 void __kprobes
arch_arm_kprobe(struct kprobe
*p
)
453 unsigned long addr
= (unsigned long)p
->addr
;
454 unsigned long arm_addr
= addr
& ~0xFULL
;
456 memcpy((char *)arm_addr
, &p
->ainsn
.insn
.bundle
, sizeof(bundle_t
));
457 flush_icache_range(arm_addr
, arm_addr
+ sizeof(bundle_t
));
460 void __kprobes
arch_disarm_kprobe(struct kprobe
*p
)
462 unsigned long addr
= (unsigned long)p
->addr
;
463 unsigned long arm_addr
= addr
& ~0xFULL
;
465 /* p->opcode contains the original unaltered bundle */
466 memcpy((char *) arm_addr
, (char *) &p
->opcode
.bundle
, sizeof(bundle_t
));
467 flush_icache_range(arm_addr
, arm_addr
+ sizeof(bundle_t
));
470 void __kprobes
arch_remove_kprobe(struct kprobe
*p
)
475 * We are resuming execution after a single step fault, so the pt_regs
476 * structure reflects the register state after we executed the instruction
477 * located in the kprobe (p->ainsn.insn.bundle). We still need to adjust
478 * the ip to point back to the original stack address. To set the IP address
479 * to original stack address, handle the case where we need to fixup the
480 * relative IP address and/or fixup branch register.
482 static void __kprobes
resume_execution(struct kprobe
*p
, struct pt_regs
*regs
)
484 unsigned long bundle_addr
= ((unsigned long) (&p
->opcode
.bundle
)) & ~0xFULL
;
485 unsigned long resume_addr
= (unsigned long)p
->addr
& ~0xFULL
;
486 unsigned long template;
487 int slot
= ((unsigned long)p
->addr
& 0xf);
489 template = p
->opcode
.bundle
.quad0
.template;
491 if (slot
== 1 && bundle_encoding
[template][1] == L
)
494 if (p
->ainsn
.inst_flag
) {
496 if (p
->ainsn
.inst_flag
& INST_FLAG_FIX_RELATIVE_IP_ADDR
) {
497 /* Fix relative IP address */
498 regs
->cr_iip
= (regs
->cr_iip
- bundle_addr
) + resume_addr
;
501 if (p
->ainsn
.inst_flag
& INST_FLAG_FIX_BRANCH_REG
) {
503 * Fix target branch register, software convention is
504 * to use either b0 or b6 or b7, so just checking
505 * only those registers
507 switch (p
->ainsn
.target_br_reg
) {
509 if ((regs
->b0
== bundle_addr
) ||
510 (regs
->b0
== bundle_addr
+ 0x10)) {
511 regs
->b0
= (regs
->b0
- bundle_addr
) +
516 if ((regs
->b6
== bundle_addr
) ||
517 (regs
->b6
== bundle_addr
+ 0x10)) {
518 regs
->b6
= (regs
->b6
- bundle_addr
) +
523 if ((regs
->b7
== bundle_addr
) ||
524 (regs
->b7
== bundle_addr
+ 0x10)) {
525 regs
->b7
= (regs
->b7
- bundle_addr
) +
535 if (regs
->cr_iip
== bundle_addr
+ 0x10) {
536 regs
->cr_iip
= resume_addr
+ 0x10;
539 if (regs
->cr_iip
== bundle_addr
) {
540 regs
->cr_iip
= resume_addr
;
545 /* Turn off Single Step bit */
546 ia64_psr(regs
)->ss
= 0;
549 static void __kprobes
prepare_ss(struct kprobe
*p
, struct pt_regs
*regs
)
551 unsigned long bundle_addr
= (unsigned long) &p
->opcode
.bundle
;
552 unsigned long slot
= (unsigned long)p
->addr
& 0xf;
554 /* single step inline if break instruction */
555 if (p
->ainsn
.inst_flag
== INST_FLAG_BREAK_INST
)
556 regs
->cr_iip
= (unsigned long)p
->addr
& ~0xFULL
;
558 regs
->cr_iip
= bundle_addr
& ~0xFULL
;
563 ia64_psr(regs
)->ri
= slot
;
565 /* turn on single stepping */
566 ia64_psr(regs
)->ss
= 1;
569 static int __kprobes
is_ia64_break_inst(struct pt_regs
*regs
)
571 unsigned int slot
= ia64_psr(regs
)->ri
;
572 unsigned int template, major_opcode
;
573 unsigned long kprobe_inst
;
574 unsigned long *kprobe_addr
= (unsigned long *)regs
->cr_iip
;
577 memcpy(&bundle
, kprobe_addr
, sizeof(bundle_t
));
578 template = bundle
.quad0
.template;
580 /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
581 if (slot
== 1 && bundle_encoding
[template][1] == L
)
584 /* Get Kprobe probe instruction at given slot*/
585 get_kprobe_inst(&bundle
, slot
, &kprobe_inst
, &major_opcode
);
587 /* For break instruction,
588 * Bits 37:40 Major opcode to be zero
589 * Bits 27:32 X6 to be zero
590 * Bits 32:35 X3 to be zero
592 if (major_opcode
|| ((kprobe_inst
>> 27) & 0x1FF) ) {
593 /* Not a break instruction */
597 /* Is a break instruction */
601 static int __kprobes
pre_kprobes_handler(struct die_args
*args
)
605 struct pt_regs
*regs
= args
->regs
;
606 kprobe_opcode_t
*addr
= (kprobe_opcode_t
*)instruction_pointer(regs
);
607 struct kprobe_ctlblk
*kcb
;
610 * We don't want to be preempted for the entire
611 * duration of kprobe processing
614 kcb
= get_kprobe_ctlblk();
616 /* Handle recursion cases */
617 if (kprobe_running()) {
618 p
= get_kprobe(addr
);
620 if ((kcb
->kprobe_status
== KPROBE_HIT_SS
) &&
621 (p
->ainsn
.inst_flag
== INST_FLAG_BREAK_INST
)) {
622 ia64_psr(regs
)->ss
= 0;
625 /* We have reentered the pre_kprobe_handler(), since
626 * another probe was hit while within the handler.
627 * We here save the original kprobes variables and
628 * just single step on the instruction of the new probe
629 * without calling any user handlers.
631 save_previous_kprobe(kcb
);
632 set_current_kprobe(p
, kcb
);
633 kprobes_inc_nmissed_count(p
);
635 kcb
->kprobe_status
= KPROBE_REENTER
;
637 } else if (args
->err
== __IA64_BREAK_JPROBE
) {
639 * jprobe instrumented function just completed
641 p
= __get_cpu_var(current_kprobe
);
642 if (p
->break_handler
&& p
->break_handler(p
, regs
)) {
651 p
= get_kprobe(addr
);
653 if (!is_ia64_break_inst(regs
)) {
655 * The breakpoint instruction was removed right
656 * after we hit it. Another cpu has removed
657 * either a probepoint or a debugger breakpoint
658 * at this address. In either case, no further
659 * handling of this interrupt is appropriate.
665 /* Not one of our break, let kernel handle it */
669 set_current_kprobe(p
, kcb
);
670 kcb
->kprobe_status
= KPROBE_HIT_ACTIVE
;
672 if (p
->pre_handler
&& p
->pre_handler(p
, regs
))
674 * Our pre-handler is specifically requesting that we just
675 * do a return. This is used for both the jprobe pre-handler
676 * and the kretprobe trampoline
682 kcb
->kprobe_status
= KPROBE_HIT_SS
;
686 preempt_enable_no_resched();
690 static int __kprobes
post_kprobes_handler(struct pt_regs
*regs
)
692 struct kprobe
*cur
= kprobe_running();
693 struct kprobe_ctlblk
*kcb
= get_kprobe_ctlblk();
698 if ((kcb
->kprobe_status
!= KPROBE_REENTER
) && cur
->post_handler
) {
699 kcb
->kprobe_status
= KPROBE_HIT_SSDONE
;
700 cur
->post_handler(cur
, regs
, 0);
703 resume_execution(cur
, regs
);
705 /*Restore back the original saved kprobes variables and continue. */
706 if (kcb
->kprobe_status
== KPROBE_REENTER
) {
707 restore_previous_kprobe(kcb
);
710 reset_current_kprobe();
713 preempt_enable_no_resched();
717 static int __kprobes
kprobes_fault_handler(struct pt_regs
*regs
, int trapnr
)
719 struct kprobe
*cur
= kprobe_running();
720 struct kprobe_ctlblk
*kcb
= get_kprobe_ctlblk();
722 if (cur
->fault_handler
&& cur
->fault_handler(cur
, regs
, trapnr
))
725 if (kcb
->kprobe_status
& KPROBE_HIT_SS
) {
726 resume_execution(cur
, regs
);
727 reset_current_kprobe();
728 preempt_enable_no_resched();
734 int __kprobes
kprobe_exceptions_notify(struct notifier_block
*self
,
735 unsigned long val
, void *data
)
737 struct die_args
*args
= (struct die_args
*)data
;
738 int ret
= NOTIFY_DONE
;
742 /* err is break number from ia64_bad_break() */
743 if (args
->err
== 0x80200 || args
->err
== 0x80300 || args
->err
== 0)
744 if (pre_kprobes_handler(args
))
748 /* err is vector number from ia64_fault() */
750 if (post_kprobes_handler(args
->regs
))
754 /* kprobe_running() needs smp_processor_id() */
756 if (kprobe_running() &&
757 kprobes_fault_handler(args
->regs
, args
->trapnr
))
766 int __kprobes
setjmp_pre_handler(struct kprobe
*p
, struct pt_regs
*regs
)
768 struct jprobe
*jp
= container_of(p
, struct jprobe
, kp
);
769 unsigned long addr
= ((struct fnptr
*)(jp
->entry
))->ip
;
770 struct kprobe_ctlblk
*kcb
= get_kprobe_ctlblk();
772 /* save architectural state */
773 kcb
->jprobe_saved_regs
= *regs
;
775 /* after rfi, execute the jprobe instrumented function */
776 regs
->cr_iip
= addr
& ~0xFULL
;
777 ia64_psr(regs
)->ri
= addr
& 0xf;
778 regs
->r1
= ((struct fnptr
*)(jp
->entry
))->gp
;
781 * fix the return address to our jprobe_inst_return() function
782 * in the jprobes.S file
784 regs
->b0
= ((struct fnptr
*)(jprobe_inst_return
))->ip
;
789 int __kprobes
longjmp_break_handler(struct kprobe
*p
, struct pt_regs
*regs
)
791 struct kprobe_ctlblk
*kcb
= get_kprobe_ctlblk();
793 *regs
= kcb
->jprobe_saved_regs
;
794 preempt_enable_no_resched();
798 static struct kprobe trampoline_p
= {
799 .pre_handler
= trampoline_probe_handler
802 int __init
arch_init_kprobes(void)
805 (kprobe_opcode_t
*)((struct fnptr
*)kretprobe_trampoline
)->ip
;
806 return register_kprobe(&trampoline_p
);