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/spinlock.h>
30 #include <linux/string.h>
31 #include <linux/slab.h>
32 #include <linux/preempt.h>
33 #include <linux/moduleloader.h>
35 #include <asm/pgtable.h>
36 #include <asm/kdebug.h>
37 #include <asm/sections.h>
39 extern void jprobe_inst_return(void);
41 /* kprobe_status settings */
42 #define KPROBE_HIT_ACTIVE 0x00000001
43 #define KPROBE_HIT_SS 0x00000002
45 static struct kprobe
*current_kprobe
, *kprobe_prev
;
46 static unsigned long kprobe_status
, kprobe_status_prev
;
47 static struct pt_regs jprobe_saved_regs
;
49 enum instruction_type
{A
, I
, M
, F
, B
, L
, X
, u
};
50 static enum instruction_type bundle_encoding
[32][3] = {
86 * In this function we check to see if the instruction
87 * is IP relative instruction and update the kprobe
88 * inst flag accordingly
90 static void __kprobes
update_kprobe_inst_flag(uint
template, uint slot
,
92 unsigned long kprobe_inst
,
95 p
->ainsn
.inst_flag
= 0;
96 p
->ainsn
.target_br_reg
= 0;
98 if (bundle_encoding
[template][slot
] == B
) {
99 switch (major_opcode
) {
100 case INDIRECT_CALL_OPCODE
:
101 p
->ainsn
.inst_flag
|= INST_FLAG_FIX_BRANCH_REG
;
102 p
->ainsn
.target_br_reg
= ((kprobe_inst
>> 6) & 0x7);
104 case IP_RELATIVE_PREDICT_OPCODE
:
105 case IP_RELATIVE_BRANCH_OPCODE
:
106 p
->ainsn
.inst_flag
|= INST_FLAG_FIX_RELATIVE_IP_ADDR
;
108 case IP_RELATIVE_CALL_OPCODE
:
109 p
->ainsn
.inst_flag
|= INST_FLAG_FIX_RELATIVE_IP_ADDR
;
110 p
->ainsn
.inst_flag
|= INST_FLAG_FIX_BRANCH_REG
;
111 p
->ainsn
.target_br_reg
= ((kprobe_inst
>> 6) & 0x7);
114 } else if (bundle_encoding
[template][slot
] == X
) {
115 switch (major_opcode
) {
116 case LONG_CALL_OPCODE
:
117 p
->ainsn
.inst_flag
|= INST_FLAG_FIX_BRANCH_REG
;
118 p
->ainsn
.target_br_reg
= ((kprobe_inst
>> 6) & 0x7);
126 * In this function we check to see if the instruction
127 * on which we are inserting kprobe is supported.
128 * Returns 0 if supported
129 * Returns -EINVAL if unsupported
131 static int __kprobes
unsupported_inst(uint
template, uint slot
,
133 unsigned long kprobe_inst
,
136 unsigned long addr
= (unsigned long)p
->addr
;
138 if (bundle_encoding
[template][slot
] == I
) {
139 switch (major_opcode
) {
140 case 0x0: //I_UNIT_MISC_OPCODE:
142 * Check for Integer speculation instruction
143 * - Bit 33-35 to be equal to 0x1
145 if (((kprobe_inst
>> 33) & 0x7) == 1) {
147 "Kprobes on speculation inst at <0x%lx> not supported\n",
153 * IP relative mov instruction
154 * - Bit 27-35 to be equal to 0x30
156 if (((kprobe_inst
>> 27) & 0x1FF) == 0x30) {
158 "Kprobes on \"mov r1=ip\" at <0x%lx> not supported\n",
170 * In this function we check to see if the instruction
171 * (qp) cmpx.crel.ctype p1,p2=r2,r3
172 * on which we are inserting kprobe is cmp instruction
175 static uint __kprobes
is_cmp_ctype_unc_inst(uint
template, uint slot
,
177 unsigned long kprobe_inst
)
182 if (!((bundle_encoding
[template][slot
] == I
) ||
183 (bundle_encoding
[template][slot
] == M
)))
186 if (!((major_opcode
== 0xC) || (major_opcode
== 0xD) ||
187 (major_opcode
== 0xE)))
190 cmp_inst
.l
= kprobe_inst
;
191 if ((cmp_inst
.f
.x2
== 0) || (cmp_inst
.f
.x2
== 1)) {
192 /* Integere compare - Register Register (A6 type)*/
193 if ((cmp_inst
.f
.tb
== 0) && (cmp_inst
.f
.ta
== 0)
194 &&(cmp_inst
.f
.c
== 1))
196 } else if ((cmp_inst
.f
.x2
== 2)||(cmp_inst
.f
.x2
== 3)) {
197 /* Integere compare - Immediate Register (A8 type)*/
198 if ((cmp_inst
.f
.ta
== 0) &&(cmp_inst
.f
.c
== 1))
206 * In this function we override the bundle with
207 * the break instruction at the given slot.
209 static void __kprobes
prepare_break_inst(uint
template, uint slot
,
211 unsigned long kprobe_inst
,
214 unsigned long break_inst
= BREAK_INST
;
215 bundle_t
*bundle
= &p
->ainsn
.insn
.bundle
;
218 * Copy the original kprobe_inst qualifying predicate(qp)
219 * to the break instruction iff !is_cmp_ctype_unc_inst
220 * because for cmp instruction with ctype equal to unc,
221 * which is a special instruction always needs to be
222 * executed regradless of qp
224 if (!is_cmp_ctype_unc_inst(template, slot
, major_opcode
, kprobe_inst
))
225 break_inst
|= (0x3f & kprobe_inst
);
229 bundle
->quad0
.slot0
= break_inst
;
232 bundle
->quad0
.slot1_p0
= break_inst
;
233 bundle
->quad1
.slot1_p1
= break_inst
>> (64-46);
236 bundle
->quad1
.slot2
= break_inst
;
241 * Update the instruction flag, so that we can
242 * emulate the instruction properly after we
243 * single step on original instruction
245 update_kprobe_inst_flag(template, slot
, major_opcode
, kprobe_inst
, p
);
248 static inline void get_kprobe_inst(bundle_t
*bundle
, uint slot
,
249 unsigned long *kprobe_inst
, uint
*major_opcode
)
251 unsigned long kprobe_inst_p0
, kprobe_inst_p1
;
252 unsigned int template;
254 template = bundle
->quad0
.template;
258 *major_opcode
= (bundle
->quad0
.slot0
>> SLOT0_OPCODE_SHIFT
);
259 *kprobe_inst
= bundle
->quad0
.slot0
;
262 *major_opcode
= (bundle
->quad1
.slot1_p1
>> SLOT1_p1_OPCODE_SHIFT
);
263 kprobe_inst_p0
= bundle
->quad0
.slot1_p0
;
264 kprobe_inst_p1
= bundle
->quad1
.slot1_p1
;
265 *kprobe_inst
= kprobe_inst_p0
| (kprobe_inst_p1
<< (64-46));
268 *major_opcode
= (bundle
->quad1
.slot2
>> SLOT2_OPCODE_SHIFT
);
269 *kprobe_inst
= bundle
->quad1
.slot2
;
274 /* Returns non-zero if the addr is in the Interrupt Vector Table */
275 static inline int in_ivt_functions(unsigned long addr
)
277 return (addr
>= (unsigned long)__start_ivt_text
278 && addr
< (unsigned long)__end_ivt_text
);
281 static int __kprobes
valid_kprobe_addr(int template, int slot
,
284 if ((slot
> 2) || ((bundle_encoding
[template][1] == L
) && slot
> 1)) {
285 printk(KERN_WARNING
"Attempting to insert unaligned kprobe "
290 if (in_ivt_functions(addr
)) {
291 printk(KERN_WARNING
"Kprobes can't be inserted inside "
292 "IVT functions at 0x%lx\n", addr
);
296 if (slot
== 1 && bundle_encoding
[template][1] != L
) {
297 printk(KERN_WARNING
"Inserting kprobes on slot #1 "
298 "is not supported\n");
305 static inline void save_previous_kprobe(void)
307 kprobe_prev
= current_kprobe
;
308 kprobe_status_prev
= kprobe_status
;
311 static inline void restore_previous_kprobe(void)
313 current_kprobe
= kprobe_prev
;
314 kprobe_status
= kprobe_status_prev
;
317 static inline void set_current_kprobe(struct kprobe
*p
)
322 static void kretprobe_trampoline(void)
327 * At this point the target function has been tricked into
328 * returning into our trampoline. Lookup the associated instance
330 * - call the handler function
331 * - cleanup by marking the instance as unused
332 * - long jump back to the original return address
334 int __kprobes
trampoline_probe_handler(struct kprobe
*p
, struct pt_regs
*regs
)
336 struct kretprobe_instance
*ri
= NULL
;
337 struct hlist_head
*head
;
338 struct hlist_node
*node
, *tmp
;
339 unsigned long orig_ret_address
= 0;
340 unsigned long trampoline_address
=
341 ((struct fnptr
*)kretprobe_trampoline
)->ip
;
343 head
= kretprobe_inst_table_head(current
);
346 * It is possible to have multiple instances associated with a given
347 * task either because an multiple functions in the call path
348 * have a return probe installed on them, and/or more then one return
349 * return probe was registered for a target function.
351 * We can handle this because:
352 * - instances are always inserted at the head of the list
353 * - when multiple return probes are registered for the same
354 * function, the first instance's ret_addr will point to the
355 * real return address, and all the rest will point to
356 * kretprobe_trampoline
358 hlist_for_each_entry_safe(ri
, node
, tmp
, head
, hlist
) {
359 if (ri
->task
!= current
)
360 /* another task is sharing our hash bucket */
363 if (ri
->rp
&& ri
->rp
->handler
)
364 ri
->rp
->handler(ri
, regs
);
366 orig_ret_address
= (unsigned long)ri
->ret_addr
;
369 if (orig_ret_address
!= trampoline_address
)
371 * This is the real return address. Any other
372 * instances associated with this task are for
373 * other calls deeper on the call stack
378 BUG_ON(!orig_ret_address
|| (orig_ret_address
== trampoline_address
));
379 regs
->cr_iip
= orig_ret_address
;
382 preempt_enable_no_resched();
385 * By returning a non-zero value, we are telling
386 * kprobe_handler() that we have handled unlocking
387 * and re-enabling preemption.
392 void __kprobes
arch_prepare_kretprobe(struct kretprobe
*rp
,
393 struct pt_regs
*regs
)
395 struct kretprobe_instance
*ri
;
397 if ((ri
= get_free_rp_inst(rp
)) != NULL
) {
400 ri
->ret_addr
= (kprobe_opcode_t
*)regs
->b0
;
402 /* Replace the return addr with trampoline addr */
403 regs
->b0
= ((struct fnptr
*)kretprobe_trampoline
)->ip
;
411 int __kprobes
arch_prepare_kprobe(struct kprobe
*p
)
413 unsigned long addr
= (unsigned long) p
->addr
;
414 unsigned long *kprobe_addr
= (unsigned long *)(addr
& ~0xFULL
);
415 unsigned long kprobe_inst
=0;
416 unsigned int slot
= addr
& 0xf, template, major_opcode
= 0;
417 bundle_t
*bundle
= &p
->ainsn
.insn
.bundle
;
419 memcpy(&p
->opcode
.bundle
, kprobe_addr
, sizeof(bundle_t
));
420 memcpy(&p
->ainsn
.insn
.bundle
, kprobe_addr
, sizeof(bundle_t
));
422 template = bundle
->quad0
.template;
424 if(valid_kprobe_addr(template, slot
, addr
))
427 /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
428 if (slot
== 1 && bundle_encoding
[template][1] == L
)
431 /* Get kprobe_inst and major_opcode from the bundle */
432 get_kprobe_inst(bundle
, slot
, &kprobe_inst
, &major_opcode
);
434 if (unsupported_inst(template, slot
, major_opcode
, kprobe_inst
, p
))
437 prepare_break_inst(template, slot
, major_opcode
, kprobe_inst
, p
);
442 void __kprobes
arch_arm_kprobe(struct kprobe
*p
)
444 unsigned long addr
= (unsigned long)p
->addr
;
445 unsigned long arm_addr
= addr
& ~0xFULL
;
447 memcpy((char *)arm_addr
, &p
->ainsn
.insn
.bundle
, sizeof(bundle_t
));
448 flush_icache_range(arm_addr
, arm_addr
+ sizeof(bundle_t
));
451 void __kprobes
arch_disarm_kprobe(struct kprobe
*p
)
453 unsigned long addr
= (unsigned long)p
->addr
;
454 unsigned long arm_addr
= addr
& ~0xFULL
;
456 /* p->opcode contains the original unaltered bundle */
457 memcpy((char *) arm_addr
, (char *) &p
->opcode
.bundle
, sizeof(bundle_t
));
458 flush_icache_range(arm_addr
, arm_addr
+ sizeof(bundle_t
));
461 void __kprobes
arch_remove_kprobe(struct kprobe
*p
)
466 * We are resuming execution after a single step fault, so the pt_regs
467 * structure reflects the register state after we executed the instruction
468 * located in the kprobe (p->ainsn.insn.bundle). We still need to adjust
469 * the ip to point back to the original stack address. To set the IP address
470 * to original stack address, handle the case where we need to fixup the
471 * relative IP address and/or fixup branch register.
473 static void __kprobes
resume_execution(struct kprobe
*p
, struct pt_regs
*regs
)
475 unsigned long bundle_addr
= ((unsigned long) (&p
->opcode
.bundle
)) & ~0xFULL
;
476 unsigned long resume_addr
= (unsigned long)p
->addr
& ~0xFULL
;
477 unsigned long template;
478 int slot
= ((unsigned long)p
->addr
& 0xf);
480 template = p
->opcode
.bundle
.quad0
.template;
482 if (slot
== 1 && bundle_encoding
[template][1] == L
)
485 if (p
->ainsn
.inst_flag
) {
487 if (p
->ainsn
.inst_flag
& INST_FLAG_FIX_RELATIVE_IP_ADDR
) {
488 /* Fix relative IP address */
489 regs
->cr_iip
= (regs
->cr_iip
- bundle_addr
) + resume_addr
;
492 if (p
->ainsn
.inst_flag
& INST_FLAG_FIX_BRANCH_REG
) {
494 * Fix target branch register, software convention is
495 * to use either b0 or b6 or b7, so just checking
496 * only those registers
498 switch (p
->ainsn
.target_br_reg
) {
500 if ((regs
->b0
== bundle_addr
) ||
501 (regs
->b0
== bundle_addr
+ 0x10)) {
502 regs
->b0
= (regs
->b0
- bundle_addr
) +
507 if ((regs
->b6
== bundle_addr
) ||
508 (regs
->b6
== bundle_addr
+ 0x10)) {
509 regs
->b6
= (regs
->b6
- bundle_addr
) +
514 if ((regs
->b7
== bundle_addr
) ||
515 (regs
->b7
== bundle_addr
+ 0x10)) {
516 regs
->b7
= (regs
->b7
- bundle_addr
) +
526 if (regs
->cr_iip
== bundle_addr
+ 0x10) {
527 regs
->cr_iip
= resume_addr
+ 0x10;
530 if (regs
->cr_iip
== bundle_addr
) {
531 regs
->cr_iip
= resume_addr
;
536 /* Turn off Single Step bit */
537 ia64_psr(regs
)->ss
= 0;
540 static void __kprobes
prepare_ss(struct kprobe
*p
, struct pt_regs
*regs
)
542 unsigned long bundle_addr
= (unsigned long) &p
->opcode
.bundle
;
543 unsigned long slot
= (unsigned long)p
->addr
& 0xf;
545 /* Update instruction pointer (IIP) and slot number (IPSR.ri) */
546 regs
->cr_iip
= bundle_addr
& ~0xFULL
;
551 ia64_psr(regs
)->ri
= slot
;
553 /* turn on single stepping */
554 ia64_psr(regs
)->ss
= 1;
557 static int __kprobes
is_ia64_break_inst(struct pt_regs
*regs
)
559 unsigned int slot
= ia64_psr(regs
)->ri
;
560 unsigned int template, major_opcode
;
561 unsigned long kprobe_inst
;
562 unsigned long *kprobe_addr
= (unsigned long *)regs
->cr_iip
;
565 memcpy(&bundle
, kprobe_addr
, sizeof(bundle_t
));
566 template = bundle
.quad0
.template;
568 /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
569 if (slot
== 1 && bundle_encoding
[template][1] == L
)
572 /* Get Kprobe probe instruction at given slot*/
573 get_kprobe_inst(&bundle
, slot
, &kprobe_inst
, &major_opcode
);
575 /* For break instruction,
576 * Bits 37:40 Major opcode to be zero
577 * Bits 27:32 X6 to be zero
578 * Bits 32:35 X3 to be zero
580 if (major_opcode
|| ((kprobe_inst
>> 27) & 0x1FF) ) {
581 /* Not a break instruction */
585 /* Is a break instruction */
589 static int __kprobes
pre_kprobes_handler(struct die_args
*args
)
593 struct pt_regs
*regs
= args
->regs
;
594 kprobe_opcode_t
*addr
= (kprobe_opcode_t
*)instruction_pointer(regs
);
598 /* Handle recursion cases */
599 if (kprobe_running()) {
600 p
= get_kprobe(addr
);
602 if (kprobe_status
== KPROBE_HIT_SS
) {
606 /* We have reentered the pre_kprobe_handler(), since
607 * another probe was hit while within the handler.
608 * We here save the original kprobes variables and
609 * just single step on the instruction of the new probe
610 * without calling any user handlers.
612 save_previous_kprobe();
613 set_current_kprobe(p
);
616 kprobe_status
= KPROBE_REENTER
;
618 } else if (args
->err
== __IA64_BREAK_JPROBE
) {
620 * jprobe instrumented function just completed
623 if (p
->break_handler
&& p
->break_handler(p
, regs
)) {
633 p
= get_kprobe(addr
);
636 if (!is_ia64_break_inst(regs
)) {
638 * The breakpoint instruction was removed right
639 * after we hit it. Another cpu has removed
640 * either a probepoint or a debugger breakpoint
641 * at this address. In either case, no further
642 * handling of this interrupt is appropriate.
648 /* Not one of our break, let kernel handle it */
652 kprobe_status
= KPROBE_HIT_ACTIVE
;
653 set_current_kprobe(p
);
655 if (p
->pre_handler
&& p
->pre_handler(p
, regs
))
657 * Our pre-handler is specifically requesting that we just
658 * do a return. This is used for both the jprobe pre-handler
659 * and the kretprobe trampoline
665 kprobe_status
= KPROBE_HIT_SS
;
669 preempt_enable_no_resched();
673 static int __kprobes
post_kprobes_handler(struct pt_regs
*regs
)
675 if (!kprobe_running())
678 if ((kprobe_status
!= KPROBE_REENTER
) && current_kprobe
->post_handler
) {
679 kprobe_status
= KPROBE_HIT_SSDONE
;
680 current_kprobe
->post_handler(current_kprobe
, regs
, 0);
683 resume_execution(current_kprobe
, regs
);
685 /*Restore back the original saved kprobes variables and continue. */
686 if (kprobe_status
== KPROBE_REENTER
) {
687 restore_previous_kprobe();
694 preempt_enable_no_resched();
698 static int __kprobes
kprobes_fault_handler(struct pt_regs
*regs
, int trapnr
)
700 if (!kprobe_running())
703 if (current_kprobe
->fault_handler
&&
704 current_kprobe
->fault_handler(current_kprobe
, regs
, trapnr
))
707 if (kprobe_status
& KPROBE_HIT_SS
) {
708 resume_execution(current_kprobe
, regs
);
710 preempt_enable_no_resched();
716 int __kprobes
kprobe_exceptions_notify(struct notifier_block
*self
,
717 unsigned long val
, void *data
)
719 struct die_args
*args
= (struct die_args
*)data
;
722 if (pre_kprobes_handler(args
))
726 if (post_kprobes_handler(args
->regs
))
730 if (kprobes_fault_handler(args
->regs
, args
->trapnr
))
738 int __kprobes
setjmp_pre_handler(struct kprobe
*p
, struct pt_regs
*regs
)
740 struct jprobe
*jp
= container_of(p
, struct jprobe
, kp
);
741 unsigned long addr
= ((struct fnptr
*)(jp
->entry
))->ip
;
743 /* save architectural state */
744 jprobe_saved_regs
= *regs
;
746 /* after rfi, execute the jprobe instrumented function */
747 regs
->cr_iip
= addr
& ~0xFULL
;
748 ia64_psr(regs
)->ri
= addr
& 0xf;
749 regs
->r1
= ((struct fnptr
*)(jp
->entry
))->gp
;
752 * fix the return address to our jprobe_inst_return() function
753 * in the jprobes.S file
755 regs
->b0
= ((struct fnptr
*)(jprobe_inst_return
))->ip
;
760 int __kprobes
longjmp_break_handler(struct kprobe
*p
, struct pt_regs
*regs
)
762 *regs
= jprobe_saved_regs
;
766 static struct kprobe trampoline_p
= {
767 .pre_handler
= trampoline_probe_handler
770 int __init
arch_init_kprobes(void)
773 (kprobe_opcode_t
*)((struct fnptr
*)kretprobe_trampoline
)->ip
;
774 return register_kprobe(&trampoline_p
);