2 * Dynamic Binary Instrumentation Module based on KProbes
3 * modules/kprobe/arch/asm-arm/dbi_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) Samsung Electronics, 2006-2010
21 * 2006-2007 Ekaterina Gorelkina <e.gorelkina@samsung.com>: initial implementation for ARM/MIPS
22 * 2008-2009 Alexey Gerenkov <a.gerenkov@samsung.com> User-Space
23 * Probes initial implementation; Support x86.
24 * 2010 Ekaterina Gorelkina <e.gorelkina@samsung.com>: redesign module for separating core and arch parts
25 * 2010-2011 Alexander Shirshikov <a.shirshikov@samsung.com>: initial implementation for Thumb
26 * 2012 Stanislav Andreev <s.andreev@samsung.com>: added time debug profiling support; BUG() message fix
27 * 2012 Stanislav Andreev <s.andreev@samsung.com>: redesign of kprobe functionality -
28 * kprobe_handler() now called via undefined instruction hooks
29 * 2012 Stanislav Andreev <s.andreev@samsung.com>: hash tables search implemented for uprobes
32 #include <linux/module.h>
35 #include "dbi_kprobes.h"
36 #include "dbi_kprobes_arm.h"
37 #include "dbi_kprobes_thumb.h"
38 #include "../dbi_kprobes.h"
39 #include "../../dbi_kprobes.h"
41 #include "../../dbi_kdebug.h"
42 #include "../../dbi_insn_slots.h"
43 #include "../../dbi_kprobes_deps.h"
46 #include <asm/cacheflush.h>
48 #ifdef TRAP_OVERHEAD_DEBUG
49 #include <linux/pid.h>
50 #include <linux/signal.h>
54 #include <linux/time.h>
57 #include <asm/traps.h>
58 #include <asm/ptrace.h>
59 #include <linux/list.h>
60 #include <linux/hash.h>
62 #define SUPRESS_BUG_MESSAGES
64 extern struct kprobe * per_cpu__current_kprobe;
65 extern struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
67 static void (*__swap_register_undef_hook)(struct undef_hook *hook);
68 static void (*__swap_unregister_undef_hook)(struct undef_hook *hook);
71 unsigned long swap_sum_time = 0;
72 unsigned long swap_sum_hit = 0;
73 EXPORT_SYMBOL_GPL (swap_sum_time);
74 EXPORT_SYMBOL_GPL (swap_sum_hit);
77 static unsigned int arr_traps_template[] = {
78 0xe1a0c00d, // mov ip, sp
79 0xe92dd800, // stmdb sp!, {fp, ip, lr, pc}
80 0xe24cb004, // sub fp, ip, #4 ; 0x4
82 0xe3500000, // cmp r0, #0 ; 0x0
83 0xe89da800, // ldmia sp, {fp, sp, pc}
89 static struct kprobe trampoline_p =
91 .addr = (kprobe_opcode_t *) & kretprobe_trampoline,
92 .pre_handler = trampoline_probe_handler
95 int prep_pc_dep_insn_execbuf(kprobe_opcode_t *insns, kprobe_opcode_t insn, int uregs)
103 for (i = 0; i < 13; i++, reg_mask <<= 1)
105 if (!(insn & reg_mask))
111 for (i = 0; i < 13; i++)
113 if ((uregs & 0x1) && (ARM_INSN_REG_RN (insn) == i))
115 if ((uregs & 0x2) && (ARM_INSN_REG_RD (insn) == i))
117 if ((uregs & 0x4) && (ARM_INSN_REG_RS (insn) == i))
119 if ((uregs & 0x8) && (ARM_INSN_REG_RM (insn) == i))
126 DBPRINTF ("there are no free register %x in insn %lx!", uregs, insn);
129 DBPRINTF ("prep_pc_dep_insn_execbuf: using R%d, changing regs %x", i, uregs);
131 // set register to save
132 ARM_INSN_REG_SET_RD (insns[0], i);
133 // set register to load address to
134 ARM_INSN_REG_SET_RD (insns[1], i);
135 // set instruction to execute and patch it
138 ARM_INSN_REG_CLEAR_MR (insn, 15);
139 ARM_INSN_REG_SET_MR (insn, i);
143 if ((uregs & 0x1) && (ARM_INSN_REG_RN (insn) == 15))
144 ARM_INSN_REG_SET_RN (insn, i);
145 if ((uregs & 0x2) && (ARM_INSN_REG_RD (insn) == 15))
146 ARM_INSN_REG_SET_RD (insn, i);
147 if ((uregs & 0x4) && (ARM_INSN_REG_RS (insn) == 15))
148 ARM_INSN_REG_SET_RS (insn, i);
149 if ((uregs & 0x8) && (ARM_INSN_REG_RM (insn) == 15))
150 ARM_INSN_REG_SET_RM (insn, i);
152 insns[UPROBES_TRAMP_INSN_IDX] = insn;
153 // set register to restore
154 ARM_INSN_REG_SET_RD (insns[3], i);
157 EXPORT_SYMBOL_GPL(prep_pc_dep_insn_execbuf);
159 int arch_check_insn_arm(struct arch_specific_insn *ainsn)
163 // check instructions that can change PC by nature
165 // ARM_INSN_MATCH (UNDEF, ainsn->insn_arm[0]) ||
166 ARM_INSN_MATCH (AUNDEF, ainsn->insn_arm[0]) ||
167 ARM_INSN_MATCH (SWI, ainsn->insn_arm[0]) ||
168 ARM_INSN_MATCH (BREAK, ainsn->insn_arm[0]) ||
169 ARM_INSN_MATCH (BL, ainsn->insn_arm[0]) ||
170 ARM_INSN_MATCH (BLX1, ainsn->insn_arm[0]) ||
171 ARM_INSN_MATCH (BLX2, ainsn->insn_arm[0]) ||
172 ARM_INSN_MATCH (BX, ainsn->insn_arm[0]) ||
173 ARM_INSN_MATCH (BXJ, ainsn->insn_arm[0]))
175 DBPRINTF ("Bad insn arch_check_insn_arm: %lx\n", ainsn->insn_arm[0]);
178 #ifndef CONFIG_CPU_V7
179 // check instructions that can write result to PC
180 else if ((ARM_INSN_MATCH (DPIS, ainsn->insn_arm[0]) ||
181 ARM_INSN_MATCH (DPRS, ainsn->insn_arm[0]) ||
182 ARM_INSN_MATCH (DPI, ainsn->insn_arm[0]) ||
183 ARM_INSN_MATCH (LIO, ainsn->insn_arm[0]) ||
184 ARM_INSN_MATCH (LRO, ainsn->insn_arm[0])) &&
185 (ARM_INSN_REG_RD (ainsn->insn_arm[0]) == 15))
187 DBPRINTF ("Bad arch_check_insn_arm: %lx\n", ainsn->insn_arm[0]);
190 #endif // CONFIG_CPU_V7
191 // check special instruction loads store multiple registers
192 else if ((ARM_INSN_MATCH (LM, ainsn->insn_arm[0]) || ARM_INSN_MATCH (SM, ainsn->insn_arm[0])) &&
193 // store pc or load to pc
194 (ARM_INSN_REG_MR (ainsn->insn_arm[0], 15) ||
195 // store/load with pc update
196 ((ARM_INSN_REG_RN (ainsn->insn_arm[0]) == 15) && (ainsn->insn_arm[0] & 0x200000))))
198 DBPRINTF ("Bad insn arch_check_insn_arm: %lx\n", ainsn->insn_arm[0]);
203 EXPORT_SYMBOL_GPL(arch_check_insn_arm);
205 int arch_prepare_kretprobe (struct kretprobe *p)
207 DBPRINTF("Warrning: arch_prepare_kretprobe is not implemented\n");
211 int arch_prepare_kprobe (struct kprobe *p)
213 kprobe_opcode_t insns[KPROBES_TRAMP_LEN];
214 int uregs, pc_dep, ret = 0;
215 kprobe_opcode_t insn[MAX_INSN_SIZE];
216 struct arch_specific_insn ainsn;
218 /* insn: must be on special executable page on i386. */
219 p->ainsn.insn = get_insn_slot(NULL, &kprobe_insn_pages, 0);
223 memcpy (insn, p->addr, MAX_INSN_SIZE * sizeof (kprobe_opcode_t));
224 ainsn.insn_arm = ainsn.insn = insn;
225 ret = arch_check_insn_arm (&ainsn);
228 p->opcode = *p->addr;
232 if(ARM_INSN_MATCH (DPIS, insn[0]) || ARM_INSN_MATCH (LRO, insn[0]) ||
233 ARM_INSN_MATCH (SRO, insn[0]))
236 if( (ARM_INSN_REG_RN (insn[0]) == 15) || (ARM_INSN_REG_RM (insn[0]) == 15) ||
237 (ARM_INSN_MATCH (SRO, insn[0]) && (ARM_INSN_REG_RD (insn[0]) == 15)) )
239 DBPRINTF ("Unboostable insn %lx, DPIS/LRO/SRO\n", insn[0]);
244 else if(ARM_INSN_MATCH (DPI, insn[0]) || ARM_INSN_MATCH (LIO, insn[0]) ||
245 ARM_INSN_MATCH (SIO, insn[0]))
248 if ((ARM_INSN_REG_RN (insn[0]) == 15) || (ARM_INSN_MATCH (SIO, insn[0]) &&
249 (ARM_INSN_REG_RD (insn[0]) == 15)))
252 DBPRINTF ("Unboostable insn %lx/%p, DPI/LIO/SIO\n", insn[0], p);
256 else if(ARM_INSN_MATCH (DPRS, insn[0]))
259 if ((ARM_INSN_REG_RN (insn[0]) == 15) || (ARM_INSN_REG_RM (insn[0]) == 15) ||
260 (ARM_INSN_REG_RS (insn[0]) == 15))
263 DBPRINTF ("Unboostable insn %lx, DPRS\n", insn[0]);
267 else if(ARM_INSN_MATCH (SM, insn[0]))
270 if (ARM_INSN_REG_MR (insn[0], 15))
272 DBPRINTF ("Unboostable insn %lx, SM\n", insn[0]);
276 // check instructions that can write result to SP andu uses PC
277 if (pc_dep && (ARM_INSN_REG_RD (ainsn.insn[0]) == 13))
279 free_insn_slot(&kprobe_insn_pages, NULL, p->ainsn.insn);
286 memcpy (insns, pc_dep_insn_execbuf, sizeof (insns));
287 if (prep_pc_dep_insn_execbuf (insns, insn[0], uregs) != 0)
289 DBPRINTF ("failed to prepare exec buffer for insn %lx!", insn[0]);
290 free_insn_slot(&kprobe_insn_pages, NULL, p->ainsn.insn);
293 insns[6] = (kprobe_opcode_t) (p->addr + 2);
297 memcpy (insns, gen_insn_execbuf, sizeof (insns));
298 insns[KPROBES_TRAMP_INSN_IDX] = insn[0];
300 insns[7] = (kprobe_opcode_t) (p->addr + 1);
301 DBPRINTF ("arch_prepare_kprobe: insn %lx", insn[0]);
302 DBPRINTF ("arch_prepare_kprobe: to %p - %lx %lx %lx %lx %lx %lx %lx %lx %lx",
303 p->ainsn.insn, insns[0], insns[1], insns[2], insns[3], insns[4],
304 insns[5], insns[6], insns[7], insns[8]);
305 memcpy (p->ainsn.insn, insns, sizeof(insns));
306 flush_icache_range((long unsigned)p->ainsn.insn, (long unsigned)(p->ainsn.insn) + sizeof(insns));
314 free_insn_slot(&kprobe_insn_pages, NULL, p->ainsn.insn);
315 printk("arch_prepare_kprobe: instruction 0x%lx not instrumentation, addr=0x%p\n", insn[0], p->addr);
321 static unsigned int arch_construct_brunch (unsigned int base, unsigned int addr, int link)
323 kprobe_opcode_t insn;
324 unsigned int bpi = (unsigned int) base - (unsigned int) addr - 8;
327 DBPRINTF ("base=%x addr=%x base-addr-8=%x\n", base, addr, bpi);
328 if (abs (insn & 0xffffff) > 0xffffff)
330 DBPRINTF ("ERROR: kprobe address out of range\n");
333 insn = insn & 0xffffff;
334 insn = insn | ((link != 0) ? 0xeb000000 : 0xea000000);
335 DBPRINTF ("insn=%lX\n", insn);
336 return (unsigned int) insn;
339 int arch_prepare_uretprobe (struct kretprobe *p, struct task_struct *task)
341 DBPRINTF("Warrning: arch_prepare_uretprobe is not implemented\n");
344 EXPORT_SYMBOL_GPL(arch_prepare_uretprobe);
346 void prepare_singlestep (struct kprobe *p, struct pt_regs *regs)
349 regs->ARM_pc = (unsigned long)p->ss_addr;
352 regs->ARM_pc = (unsigned long)p->ainsn.insn;
355 EXPORT_SYMBOL_GPL(prepare_singlestep);
357 void save_previous_kprobe(struct kprobe_ctlblk *kcb, struct kprobe *p_run)
360 panic("arm_save_previous_kprobe: p_run == NULL\n");
363 if (kcb->prev_kprobe.kp != NULL) {
364 DBPRINTF ("no space to save new probe[]: task = %d/%s", current->pid, current->comm);
367 kcb->prev_kprobe.kp = p_run;
368 kcb->prev_kprobe.status = kcb->kprobe_status;
371 void restore_previous_kprobe(struct kprobe_ctlblk *kcb)
373 set_current_kprobe(kcb->prev_kprobe.kp, NULL, NULL);
374 kcb->kprobe_status = kcb->prev_kprobe.status;
375 kcb->prev_kprobe.kp = NULL;
376 kcb->prev_kprobe.status = 0;
379 void set_current_kprobe(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb)
381 __get_cpu_var(current_kprobe) = p;
382 DBPRINTF ("set_current_kprobe: p=%p addr=%p\n", p, p->addr);
384 EXPORT_SYMBOL_GPL(set_current_kprobe);
386 #ifdef TRAP_OVERHEAD_DEBUG
387 static unsigned long trap_handler_counter_debug = 0;
388 #define SAMPLING_COUNTER 100000
391 static int kprobe_handler(struct pt_regs *regs)
394 char *msg_out = NULL;
395 kprobe_opcode_t *addr = (kprobe_opcode_t *) (regs->ARM_pc);
397 struct kprobe *p = NULL, *p_run = NULL;
398 int ret = 0, reenter = 0;
399 kprobe_opcode_t *ssaddr = NULL;
400 struct kprobe_ctlblk *kcb;
402 #ifdef SUPRESS_BUG_MESSAGES
403 int swap_oops_in_progress;
404 // oops_in_progress used to avoid BUG() messages that slow down kprobe_handler() execution
405 swap_oops_in_progress = oops_in_progress;
406 oops_in_progress = 1;
408 #ifdef TRAP_OVERHEAD_DEBUG
409 trap_handler_counter_debug++;
410 if ( trap_handler_counter_debug < SAMPLING_COUNTER ) {
414 // XXX NOTE - user must care about catching signal via signal handler to avoid hanging!
415 printk("Trap %ld reached - send SIGUSR1\n", trap_handler_counter_debug);
416 kill_pid(get_task_pid(current, PIDTYPE_PID), SIGUSR1, 1);
417 trap_handler_counter_debug = 0;
422 #ifdef OVERHEAD_DEBUG
423 struct timeval swap_tv1;
424 struct timeval swap_tv2;
425 #define USEC_IN_SEC_NUM 1000000
426 do_gettimeofday(&swap_tv1);
430 p = get_kprobe(addr, 0);
432 /* We're in an interrupt, but this is clear and BUG()-safe. */
433 kcb = get_kprobe_ctlblk ();
435 /* Check we're not actually recursing */
436 // TODO: event is not saving in trace
437 p_run = kprobe_running();
443 if (addr == (kprobe_opcode_t *)kretprobe_trampoline) {
444 save_previous_kprobe(kcb, p_run);
445 kcb->kprobe_status = KPROBE_REENTER;
448 /* We have reentered the kprobe_handler(), since
449 * another probe was hit while within the handler.
450 * We here save the original kprobes variables and
451 * just single step on the instruction of the new probe
452 * without calling any user handlers.
454 kprobes_inc_nmissed_count (p);
455 prepare_singlestep (p, regs);
463 DBPRINTF ("kprobe_running !!! p = 0x%p p->break_handler = 0x%p", p, p->break_handler);
464 /*if (p->break_handler && p->break_handler(p, regs)) {
465 DBPRINTF("kprobe_running !!! goto ss");
468 DBPRINTF ("unknown uprobe at %p cur at %p/%p\n", addr, p->addr, p->ainsn.insn);
469 ssaddr = p->ainsn.insn + KPROBES_TRAMP_SS_BREAK_IDX;
470 if (addr == ssaddr) {
471 regs->ARM_pc = (unsigned long) (p->addr + 1);
472 DBPRINTF ("finish step at %p cur at %p/%p, redirect to %lx\n", addr, p->addr, p->ainsn.insn, regs->ARM_pc);
473 if (kcb->kprobe_status == KPROBE_REENTER) {
474 restore_previous_kprobe(kcb);
476 reset_current_kprobe();
479 DBPRINTF ("kprobe_running !!! goto no");
481 /* If it's not ours, can't be delete race, (we hold lock). */
482 DBPRINTF ("no_kprobe");
489 /* Not one of ours: let kernel handle it */
490 DBPRINTF ("no_kprobe");
494 set_current_kprobe(p, NULL, NULL);
496 kcb->kprobe_status = KPROBE_HIT_ACTIVE;
498 if (p->pre_handler) {
499 ret = p->pre_handler (p, regs);
500 if(p->pre_handler != trampoline_probe_handler) {
501 reset_current_kprobe();
506 /* handler has already set things up, so skip ss setup */
512 msg_out = "no_kprobe\n";
513 err_out = 1; // return with death
517 preempt_enable_no_resched();
518 #ifdef OVERHEAD_DEBUG
519 do_gettimeofday(&swap_tv2);
521 swap_sum_time += ((swap_tv2.tv_sec - swap_tv1.tv_sec) * USEC_IN_SEC_NUM +
522 (swap_tv2.tv_usec - swap_tv1.tv_usec));
524 #ifdef SUPRESS_BUG_MESSAGES
525 oops_in_progress = swap_oops_in_progress;
535 int kprobe_trap_handler(struct pt_regs *regs, unsigned int instr)
539 local_irq_save(flags);
540 ret = kprobe_handler(regs);
541 local_irq_restore(flags);
545 int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
547 struct jprobe *jp = container_of(p, struct jprobe, kp);
548 kprobe_pre_entry_handler_t pre_entry = (kprobe_pre_entry_handler_t)jp->pre_entry;
549 entry_point_t entry = (entry_point_t)jp->entry;
550 pre_entry = (kprobe_pre_entry_handler_t)jp->pre_entry;
553 panic("setjmp_pre_handler: p->tgid == 0");
556 if (((unsigned long)p->addr == sched_addr) && sched_rp) {
557 struct thread_info *tinfo = (struct thread_info *)regs->ARM_r2;
558 patch_suspended_task(sched_rp, tinfo->task);
562 p->ss_addr = (void *)pre_entry (jp->priv_arg, regs);
566 entry(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2,
567 regs->ARM_r3, regs->ARM_r4, regs->ARM_r5);
572 prepare_singlestep(p, regs);
577 void dbi_jprobe_return (void)
581 void dbi_arch_uprobe_return (void)
584 EXPORT_SYMBOL_GPL(dbi_arch_uprobe_return);
586 int longjmp_break_handler (struct kprobe *p, struct pt_regs *regs)
589 //kprobe_opcode_t insn = BREAKPOINT_INSTRUCTION;
590 kprobe_opcode_t insns[2];
594 insns[0] = BREAKPOINT_INSTRUCTION;
595 insns[1] = p->opcode;
596 //p->opcode = *p->addr;
597 if (read_proc_vm_atomic (current, (unsigned long) (p->addr), &(p->opcode), sizeof (p->opcode)) < sizeof (p->opcode))
599 printk ("ERROR[%lu]: failed to read vm of proc %s/%u addr %p.", nCount, current->comm, current->pid, p->addr);
602 //*p->addr = BREAKPOINT_INSTRUCTION;
603 //*(p->addr+1) = p->opcode;
604 if (write_proc_vm_atomic (current, (unsigned long) (p->addr), insns, sizeof (insns)) < sizeof (insns))
606 printk ("ERROR[%lu]: failed to write vm of proc %s/%u addr %p.", nCount, current->comm, current->pid, p->addr);
612 DBPRINTF ("p->opcode = 0x%lx *p->addr = 0x%lx p->addr = 0x%p\n", p->opcode, *p->addr, p->addr);
613 *(p->addr + 1) = p->opcode;
614 p->opcode = *p->addr;
615 *p->addr = BREAKPOINT_INSTRUCTION;
617 flush_icache_range ((unsigned int) p->addr, (unsigned int) (((unsigned int) p->addr) + (sizeof (kprobe_opcode_t) * 2)));
620 reset_current_kprobe();
626 EXPORT_SYMBOL_GPL(longjmp_break_handler);
628 void arch_arm_kprobe (struct kprobe *p)
630 *p->addr = BREAKPOINT_INSTRUCTION;
631 flush_icache_range ((unsigned long) p->addr, (unsigned long) p->addr + sizeof (kprobe_opcode_t));
634 void arch_disarm_kprobe (struct kprobe *p)
636 *p->addr = p->opcode;
637 flush_icache_range ((unsigned long) p->addr, (unsigned long) p->addr + sizeof (kprobe_opcode_t));
641 int trampoline_probe_handler (struct kprobe *p, struct pt_regs *regs)
643 struct kretprobe_instance *ri = NULL;
644 struct hlist_head *head;
645 struct hlist_node *node, *tmp;
646 unsigned long flags, orig_ret_address = 0;
647 unsigned long trampoline_address = (unsigned long) &kretprobe_trampoline;
649 struct kretprobe *crp = NULL;
650 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk ();
655 // in case of user space retprobe trampoline is at the Nth instruction of US tramp
656 if (!thumb_mode( regs ))
657 trampoline_address = (unsigned long)(p->ainsn.insn + UPROBES_TRAMP_RET_BREAK_IDX);
659 trampoline_address = (unsigned long)(p->ainsn.insn) + 0x1b;
662 spin_lock_irqsave (&kretprobe_lock, flags);
665 * We are using different hash keys (current and mm) for finding kernel
666 * space and user space probes. Kernel space probes can change mm field in
667 * task_struct. User space probes can be shared between threads of one
668 * process so they have different current but same mm.
671 head = kretprobe_inst_table_head(current->mm);
673 head = kretprobe_inst_table_head(current);
677 * It is possible to have multiple instances associated with a given
678 * task either because an multiple functions in the call path
679 * have a return probe installed on them, and/or more then one
680 * return probe was registered for a target function.
682 * We can handle this because:
683 * - instances are always inserted at the head of the list
684 * - when multiple return probes are registered for the same
685 * function, the first instance's ret_addr will point to the
686 * real return address, and all the rest will point to
687 * kretprobe_trampoline
689 hlist_for_each_entry_safe (ri, node, tmp, head, hlist)
691 if (ri->task != current)
692 /* another task is sharing our hash bucket */
694 if (ri->rp && ri->rp->handler){
695 ri->rp->handler (ri, regs, ri->rp->priv_arg);
698 orig_ret_address = (unsigned long) ri->ret_addr;
699 recycle_rp_inst (ri);
700 if (orig_ret_address != trampoline_address)
702 * This is the real return address. Any other
703 * instances associated with this task are for
704 * other calls deeper on the call stack
708 kretprobe_assert (ri, orig_ret_address, trampoline_address);
709 //BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address));
710 //E.G. Check this code in case of __switch_to function instrumentation -- currently this code generates dump in this case
711 //if (trampoline_address != (unsigned long) &kretprobe_trampoline){
712 //if (ri->rp2) BUG_ON (ri->rp2->kp.tgid == 0);
713 //if (ri->rp) BUG_ON (ri->rp->kp.tgid == 0);
714 //else if (ri->rp2) BUG_ON (ri->rp2->kp.tgid == 0);
716 if ((ri->rp && ri->rp->kp.tgid) || (ri->rp2 && ri->rp2->kp.tgid))
717 BUG_ON (trampoline_address == (unsigned long) &kretprobe_trampoline);
719 regs->uregs[14] = orig_ret_address;
720 DBPRINTF ("regs->uregs[14] = 0x%lx\n", regs->uregs[14]);
721 DBPRINTF ("regs->uregs[15] = 0x%lx\n", regs->uregs[15]);
723 if (trampoline_address != (unsigned long) &kretprobe_trampoline)
725 regs->uregs[15] = orig_ret_address;
727 if (!thumb_mode( regs )) regs->uregs[15] += 4;
728 else regs->uregs[15] += 2;
731 DBPRINTF ("regs->uregs[15] = 0x%lx\n", regs->uregs[15]);
733 if(p){ // ARM, MIPS, X86 user space
734 if (thumb_mode( regs ) && !(regs->uregs[14] & 0x01))
736 regs->ARM_cpsr &= 0xFFFFFFDF;
738 if (user_mode( regs ) && (regs->uregs[14] & 0x01))
740 regs->ARM_cpsr |= 0x20;
744 //TODO: test - enter function, delete us retprobe, exit function
745 // for user space retprobes only - deferred deletion
747 if (trampoline_address != (unsigned long) &kretprobe_trampoline)
749 // if we are not at the end of the list and current retprobe should be disarmed
752 struct hlist_node *current_node = node;
754 /*sprintf(die_msg, "deferred disarm p->addr = %p [%lx %lx %lx]\n",
755 crp->kp.addr, *kaddrs[0], *kaddrs[1], *kaddrs[2]);
756 DIE(die_msg, regs); */
757 // look for other instances for the same retprobe
758 hlist_for_each_entry_safe (ri, node, tmp, head, hlist)
761 * Trying to find another retprobe instance associated with
764 if (ri->rp2 == crp && node != current_node)
770 // if there are no more instances for this retprobe
772 struct kprobe *is_p = &crp->kp;
773 DBPRINTF ("defered retprobe deletion p->addr = %p", crp->kp.addr);
775 If there is no any retprobe instances of this retprobe
776 we can free the resources related to the probe.
778 if (!(hlist_unhashed(&is_p->is_hlist_arm))) {
779 hlist_del_rcu(&is_p->is_hlist_arm);
781 if (!(hlist_unhashed(&is_p->is_hlist_thumb))) {
782 hlist_del_rcu(&is_p->is_hlist_thumb);
785 dbi_unregister_kprobe(&crp->kp, current);
788 hlist_del(current_node);
792 if (kcb->kprobe_status == KPROBE_REENTER) {
793 restore_previous_kprobe(kcb);
795 reset_current_kprobe();
799 spin_unlock_irqrestore (&kretprobe_lock, flags);
802 * By returning a non-zero value, we are telling
803 * kprobe_handler() that we don't want the post_handler
804 * to run (and have re-enabled preemption)
809 EXPORT_SYMBOL_GPL(trampoline_probe_handler);
811 void __arch_prepare_kretprobe (struct kretprobe *rp, struct pt_regs *regs)
813 struct kretprobe_instance *ri;
815 DBPRINTF ("start\n");
816 //TODO: test - remove retprobe after func entry but before its exit
817 if ((ri = get_free_rp_inst (rp)) != NULL)
822 ri->ret_addr = (kprobe_opcode_t *) regs->uregs[14];
823 ri->sp = (kprobe_opcode_t *)regs->ARM_sp; //uregs[13];
826 if (!thumb_mode( regs ))
827 regs->uregs[14] = (unsigned long) (rp->kp.ainsn.insn + UPROBES_TRAMP_RET_BREAK_IDX);
829 regs->uregs[14] = (unsigned long) (rp->kp.ainsn.insn) + 0x1b;
831 else /* Replace the return addr with trampoline addr */
832 regs->uregs[14] = (unsigned long) &kretprobe_trampoline;
834 // DBPRINTF ("ret addr set to %p->%lx\n", ri->ret_addr, regs->uregs[14]);
838 DBPRINTF ("WARNING: missed retprobe %p\n", rp->kp.addr);
844 int asm_init_module_dependencies(void)
846 //No module dependencies
850 void swap_register_undef_hook(struct undef_hook *hook)
852 __swap_register_undef_hook(hook);
854 EXPORT_SYMBOL_GPL(swap_register_undef_hook);
856 void swap_unregister_undef_hook(struct undef_hook *hook)
858 __swap_unregister_undef_hook(hook);
860 EXPORT_SYMBOL_GPL(swap_unregister_undef_hook);
862 // kernel probes hook
863 static struct undef_hook undef_ho_k = {
864 .instr_mask = 0xffffffff,
865 .instr_val = BREAKPOINT_INSTRUCTION,
866 .cpsr_mask = MODE_MASK,
867 .cpsr_val = SVC_MODE,
868 .fn = kprobe_trap_handler
871 int __init arch_init_kprobes (void)
873 unsigned int do_bp_handler = 0;
876 if (arch_init_module_dependencies())
878 DBPRINTF ("Unable to init module dependencies\n");
882 do_bp_handler = swap_ksyms("do_undefinstr");
883 if (do_bp_handler == 0) {
884 DBPRINTF("no do_undefinstr symbol found!");
887 arr_traps_template[NOTIFIER_CALL_CHAIN_INDEX] = arch_construct_brunch ((unsigned int)kprobe_handler, do_bp_handler + NOTIFIER_CALL_CHAIN_INDEX * 4, 1);
888 // Register hooks (kprobe_handler)
889 __swap_register_undef_hook = swap_ksyms("register_undef_hook");
890 if (__swap_register_undef_hook == NULL) {
891 printk("no register_undef_hook symbol found!\n");
895 // Unregister hooks (kprobe_handler)
896 __swap_unregister_undef_hook = swap_ksyms("unregister_undef_hook");
897 if (__swap_unregister_undef_hook == NULL) {
898 printk("no unregister_undef_hook symbol found!\n");
902 swap_register_undef_hook(&undef_ho_k);
903 if ((ret = dbi_register_kprobe (&trampoline_p)) != 0) {
904 //dbi_unregister_jprobe(&do_exit_p, 0);
910 void __exit dbi_arch_exit_kprobes (void)
912 swap_unregister_undef_hook(&undef_ho_k);
915 //EXPORT_SYMBOL_GPL (dbi_arch_uprobe_return);
916 //EXPORT_SYMBOL_GPL (dbi_arch_exit_kprobes);