1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Kernel Probes (KProbes)
4 * arch/ia64/kernel/kprobes.c
6 * Copyright (C) IBM Corporation, 2002, 2004
7 * Copyright (C) Intel Corporation, 2005
9 * 2005-Apr Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy
10 * <anil.s.keshavamurthy@intel.com> adapted from i386
13 #include <linux/kprobes.h>
14 #include <linux/ptrace.h>
15 #include <linux/string.h>
16 #include <linux/slab.h>
17 #include <linux/preempt.h>
18 #include <linux/extable.h>
19 #include <linux/kdebug.h>
21 #include <asm/pgtable.h>
22 #include <asm/sections.h>
23 #include <asm/exception.h>
25 DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
26 DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
28 struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
30 enum instruction_type {A, I, M, F, B, L, X, u};
31 static enum instruction_type bundle_encoding[32][3] = {
66 /* Insert a long branch code */
67 static void __kprobes set_brl_inst(void *from, void *to)
69 s64 rel = ((s64) to - (s64) from) >> 4;
71 brl = (bundle_t *) ((u64) from & ~0xf);
72 brl->quad0.template = 0x05; /* [MLX](stop) */
73 brl->quad0.slot0 = NOP_M_INST; /* nop.m 0x0 */
74 brl->quad0.slot1_p0 = ((rel >> 20) & 0x7fffffffff) << 2;
75 brl->quad1.slot1_p1 = (((rel >> 20) & 0x7fffffffff) << 2) >> (64 - 46);
76 /* brl.cond.sptk.many.clr rel<<4 (qp=0) */
77 brl->quad1.slot2 = BRL_INST(rel >> 59, rel & 0xfffff);
81 * In this function we check to see if the instruction
82 * is IP relative instruction and update the kprobe
83 * inst flag accordingly
85 static void __kprobes update_kprobe_inst_flag(uint template, uint slot,
87 unsigned long kprobe_inst,
90 p->ainsn.inst_flag = 0;
91 p->ainsn.target_br_reg = 0;
94 /* Check for Break instruction
95 * Bits 37:40 Major opcode to be zero
96 * Bits 27:32 X6 to be zero
97 * Bits 32:35 X3 to be zero
99 if ((!major_opcode) && (!((kprobe_inst >> 27) & 0x1FF)) ) {
100 /* is a break instruction */
101 p->ainsn.inst_flag |= INST_FLAG_BREAK_INST;
105 if (bundle_encoding[template][slot] == B) {
106 switch (major_opcode) {
107 case INDIRECT_CALL_OPCODE:
108 p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
109 p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
111 case IP_RELATIVE_PREDICT_OPCODE:
112 case IP_RELATIVE_BRANCH_OPCODE:
113 p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
115 case IP_RELATIVE_CALL_OPCODE:
116 p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
117 p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
118 p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
121 } else if (bundle_encoding[template][slot] == X) {
122 switch (major_opcode) {
123 case LONG_CALL_OPCODE:
124 p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
125 p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
133 * In this function we check to see if the instruction
134 * (qp) cmpx.crel.ctype p1,p2=r2,r3
135 * on which we are inserting kprobe is cmp instruction
138 static uint __kprobes is_cmp_ctype_unc_inst(uint template, uint slot,
140 unsigned long kprobe_inst)
145 if (!((bundle_encoding[template][slot] == I) ||
146 (bundle_encoding[template][slot] == M)))
149 if (!((major_opcode == 0xC) || (major_opcode == 0xD) ||
150 (major_opcode == 0xE)))
153 cmp_inst.l = kprobe_inst;
154 if ((cmp_inst.f.x2 == 0) || (cmp_inst.f.x2 == 1)) {
155 /* Integer compare - Register Register (A6 type)*/
156 if ((cmp_inst.f.tb == 0) && (cmp_inst.f.ta == 0)
157 &&(cmp_inst.f.c == 1))
159 } else if ((cmp_inst.f.x2 == 2)||(cmp_inst.f.x2 == 3)) {
160 /* Integer compare - Immediate Register (A8 type)*/
161 if ((cmp_inst.f.ta == 0) &&(cmp_inst.f.c == 1))
169 * In this function we check to see if the instruction
170 * on which we are inserting kprobe is supported.
171 * Returns qp value if supported
172 * Returns -EINVAL if unsupported
174 static int __kprobes unsupported_inst(uint template, uint slot,
176 unsigned long kprobe_inst,
181 qp = kprobe_inst & 0x3f;
182 if (is_cmp_ctype_unc_inst(template, slot, major_opcode, kprobe_inst)) {
183 if (slot == 1 && qp) {
184 printk(KERN_WARNING "Kprobes on cmp unc "
185 "instruction on slot 1 at <0x%lx> "
186 "is not supported\n", addr);
192 else if (bundle_encoding[template][slot] == I) {
193 if (major_opcode == 0) {
195 * Check for Integer speculation instruction
196 * - Bit 33-35 to be equal to 0x1
198 if (((kprobe_inst >> 33) & 0x7) == 1) {
200 "Kprobes on speculation inst at <0x%lx> not supported\n",
205 * IP relative mov instruction
206 * - Bit 27-35 to be equal to 0x30
208 if (((kprobe_inst >> 27) & 0x1FF) == 0x30) {
210 "Kprobes on \"mov r1=ip\" at <0x%lx> not supported\n",
216 else if ((major_opcode == 5) && !(kprobe_inst & (0xFUl << 33)) &&
217 (kprobe_inst & (0x1UL << 12))) {
218 /* test bit instructions, tbit,tnat,tf
219 * bit 33-36 to be equal to 0
220 * bit 12 to be equal to 1
222 if (slot == 1 && qp) {
223 printk(KERN_WARNING "Kprobes on test bit "
224 "instruction on slot at <0x%lx> "
225 "is not supported\n", addr);
231 else if (bundle_encoding[template][slot] == B) {
232 if (major_opcode == 7) {
233 /* IP-Relative Predict major code is 7 */
234 printk(KERN_WARNING "Kprobes on IP-Relative"
235 "Predict is not supported\n");
238 else if (major_opcode == 2) {
239 /* Indirect Predict, major code is 2
240 * bit 27-32 to be equal to 10 or 11
242 int x6=(kprobe_inst >> 27) & 0x3F;
243 if ((x6 == 0x10) || (x6 == 0x11)) {
244 printk(KERN_WARNING "Kprobes on "
245 "Indirect Predict is not supported\n");
250 /* kernel does not use float instruction, here for safety kprobe
251 * will judge whether it is fcmp/flass/float approximation instruction
253 else if (unlikely(bundle_encoding[template][slot] == F)) {
254 if ((major_opcode == 4 || major_opcode == 5) &&
255 (kprobe_inst & (0x1 << 12))) {
256 /* fcmp/fclass unc instruction */
257 if (slot == 1 && qp) {
258 printk(KERN_WARNING "Kprobes on fcmp/fclass "
259 "instruction on slot at <0x%lx> "
260 "is not supported\n", addr);
266 if ((major_opcode == 0 || major_opcode == 1) &&
267 (kprobe_inst & (0x1UL << 33))) {
268 /* float Approximation instruction */
269 if (slot == 1 && qp) {
270 printk(KERN_WARNING "Kprobes on float Approx "
271 "instr at <0x%lx> is not supported\n",
282 * In this function we override the bundle with
283 * the break instruction at the given slot.
285 static void __kprobes prepare_break_inst(uint template, uint slot,
287 unsigned long kprobe_inst,
291 unsigned long break_inst = BREAK_INST;
292 bundle_t *bundle = &p->opcode.bundle;
295 * Copy the original kprobe_inst qualifying predicate(qp)
296 * to the break instruction
302 bundle->quad0.slot0 = break_inst;
305 bundle->quad0.slot1_p0 = break_inst;
306 bundle->quad1.slot1_p1 = break_inst >> (64-46);
309 bundle->quad1.slot2 = break_inst;
314 * Update the instruction flag, so that we can
315 * emulate the instruction properly after we
316 * single step on original instruction
318 update_kprobe_inst_flag(template, slot, major_opcode, kprobe_inst, p);
321 static void __kprobes get_kprobe_inst(bundle_t *bundle, uint slot,
322 unsigned long *kprobe_inst, uint *major_opcode)
324 unsigned long kprobe_inst_p0, kprobe_inst_p1;
325 unsigned int template;
327 template = bundle->quad0.template;
331 *major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT);
332 *kprobe_inst = bundle->quad0.slot0;
335 *major_opcode = (bundle->quad1.slot1_p1 >> SLOT1_p1_OPCODE_SHIFT);
336 kprobe_inst_p0 = bundle->quad0.slot1_p0;
337 kprobe_inst_p1 = bundle->quad1.slot1_p1;
338 *kprobe_inst = kprobe_inst_p0 | (kprobe_inst_p1 << (64-46));
341 *major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT);
342 *kprobe_inst = bundle->quad1.slot2;
347 /* Returns non-zero if the addr is in the Interrupt Vector Table */
348 static int __kprobes in_ivt_functions(unsigned long addr)
350 return (addr >= (unsigned long)__start_ivt_text
351 && addr < (unsigned long)__end_ivt_text);
354 static int __kprobes valid_kprobe_addr(int template, int slot,
357 if ((slot > 2) || ((bundle_encoding[template][1] == L) && slot > 1)) {
358 printk(KERN_WARNING "Attempting to insert unaligned kprobe "
363 if (in_ivt_functions(addr)) {
364 printk(KERN_WARNING "Kprobes can't be inserted inside "
365 "IVT functions at 0x%lx\n", addr);
372 static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
375 i = atomic_add_return(1, &kcb->prev_kprobe_index);
376 kcb->prev_kprobe[i-1].kp = kprobe_running();
377 kcb->prev_kprobe[i-1].status = kcb->kprobe_status;
380 static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
383 i = atomic_read(&kcb->prev_kprobe_index);
384 __this_cpu_write(current_kprobe, kcb->prev_kprobe[i-1].kp);
385 kcb->kprobe_status = kcb->prev_kprobe[i-1].status;
386 atomic_sub(1, &kcb->prev_kprobe_index);
389 static void __kprobes set_current_kprobe(struct kprobe *p,
390 struct kprobe_ctlblk *kcb)
392 __this_cpu_write(current_kprobe, p);
395 static void kretprobe_trampoline(void)
400 * At this point the target function has been tricked into
401 * returning into our trampoline. Lookup the associated instance
403 * - call the handler function
404 * - cleanup by marking the instance as unused
405 * - long jump back to the original return address
407 int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
409 struct kretprobe_instance *ri = NULL;
410 struct hlist_head *head, empty_rp;
411 struct hlist_node *tmp;
412 unsigned long flags, orig_ret_address = 0;
413 unsigned long trampoline_address =
414 (unsigned long)dereference_function_descriptor(kretprobe_trampoline);
416 INIT_HLIST_HEAD(&empty_rp);
417 kretprobe_hash_lock(current, &head, &flags);
420 * It is possible to have multiple instances associated with a given
421 * task either because an multiple functions in the call path
422 * have a return probe installed on them, and/or more than one return
423 * return probe was registered for a target function.
425 * We can handle this because:
426 * - instances are always inserted at the head of the list
427 * - when multiple return probes are registered for the same
428 * function, the first instance's ret_addr will point to the
429 * real return address, and all the rest will point to
430 * kretprobe_trampoline
432 hlist_for_each_entry_safe(ri, tmp, head, hlist) {
433 if (ri->task != current)
434 /* another task is sharing our hash bucket */
437 orig_ret_address = (unsigned long)ri->ret_addr;
438 if (orig_ret_address != trampoline_address)
440 * This is the real return address. Any other
441 * instances associated with this task are for
442 * other calls deeper on the call stack
447 regs->cr_iip = orig_ret_address;
449 hlist_for_each_entry_safe(ri, tmp, head, hlist) {
450 if (ri->task != current)
451 /* another task is sharing our hash bucket */
454 if (ri->rp && ri->rp->handler)
455 ri->rp->handler(ri, regs);
457 orig_ret_address = (unsigned long)ri->ret_addr;
458 recycle_rp_inst(ri, &empty_rp);
460 if (orig_ret_address != trampoline_address)
462 * This is the real return address. Any other
463 * instances associated with this task are for
464 * other calls deeper on the call stack
468 kretprobe_assert(ri, orig_ret_address, trampoline_address);
470 kretprobe_hash_unlock(current, &flags);
472 hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
473 hlist_del(&ri->hlist);
477 * By returning a non-zero value, we are telling
478 * kprobe_handler() that we don't want the post_handler
479 * to run (and have re-enabled preemption)
484 void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
485 struct pt_regs *regs)
487 ri->ret_addr = (kprobe_opcode_t *)regs->b0;
489 /* Replace the return addr with trampoline addr */
490 regs->b0 = (unsigned long)dereference_function_descriptor(kretprobe_trampoline);
493 /* Check the instruction in the slot is break */
494 static int __kprobes __is_ia64_break_inst(bundle_t *bundle, uint slot)
496 unsigned int major_opcode;
497 unsigned int template = bundle->quad0.template;
498 unsigned long kprobe_inst;
500 /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
501 if (slot == 1 && bundle_encoding[template][1] == L)
504 /* Get Kprobe probe instruction at given slot*/
505 get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
507 /* For break instruction,
508 * Bits 37:40 Major opcode to be zero
509 * Bits 27:32 X6 to be zero
510 * Bits 32:35 X3 to be zero
512 if (major_opcode || ((kprobe_inst >> 27) & 0x1FF)) {
513 /* Not a break instruction */
517 /* Is a break instruction */
522 * In this function, we check whether the target bundle modifies IP or
523 * it triggers an exception. If so, it cannot be boostable.
525 static int __kprobes can_boost(bundle_t *bundle, uint slot,
526 unsigned long bundle_addr)
528 unsigned int template = bundle->quad0.template;
531 if (search_exception_tables(bundle_addr + slot) ||
532 __is_ia64_break_inst(bundle, slot))
533 return 0; /* exception may occur in this bundle*/
534 } while ((++slot) < 3);
536 if (template >= 0x10 /* including B unit */ ||
537 template == 0x04 /* including X unit */ ||
538 template == 0x06) /* undefined */
544 /* Prepare long jump bundle and disables other boosters if need */
545 static void __kprobes prepare_booster(struct kprobe *p)
547 unsigned long addr = (unsigned long)p->addr & ~0xFULL;
548 unsigned int slot = (unsigned long)p->addr & 0xf;
549 struct kprobe *other_kp;
551 if (can_boost(&p->ainsn.insn[0].bundle, slot, addr)) {
552 set_brl_inst(&p->ainsn.insn[1].bundle, (bundle_t *)addr + 1);
553 p->ainsn.inst_flag |= INST_FLAG_BOOSTABLE;
556 /* disables boosters in previous slots */
557 for (; addr < (unsigned long)p->addr; addr++) {
558 other_kp = get_kprobe((void *)addr);
560 other_kp->ainsn.inst_flag &= ~INST_FLAG_BOOSTABLE;
564 int __kprobes arch_prepare_kprobe(struct kprobe *p)
566 unsigned long addr = (unsigned long) p->addr;
567 unsigned long *kprobe_addr = (unsigned long *)(addr & ~0xFULL);
568 unsigned long kprobe_inst=0;
569 unsigned int slot = addr & 0xf, template, major_opcode = 0;
573 bundle = &((kprobe_opcode_t *)kprobe_addr)->bundle;
574 template = bundle->quad0.template;
576 if(valid_kprobe_addr(template, slot, addr))
579 /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
580 if (slot == 1 && bundle_encoding[template][1] == L)
583 /* Get kprobe_inst and major_opcode from the bundle */
584 get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
586 qp = unsupported_inst(template, slot, major_opcode, kprobe_inst, addr);
590 p->ainsn.insn = get_insn_slot();
593 memcpy(&p->opcode, kprobe_addr, sizeof(kprobe_opcode_t));
594 memcpy(p->ainsn.insn, kprobe_addr, sizeof(kprobe_opcode_t));
596 prepare_break_inst(template, slot, major_opcode, kprobe_inst, p, qp);
603 void __kprobes arch_arm_kprobe(struct kprobe *p)
605 unsigned long arm_addr;
606 bundle_t *src, *dest;
608 arm_addr = ((unsigned long)p->addr) & ~0xFUL;
609 dest = &((kprobe_opcode_t *)arm_addr)->bundle;
610 src = &p->opcode.bundle;
612 flush_icache_range((unsigned long)p->ainsn.insn,
613 (unsigned long)p->ainsn.insn +
614 sizeof(kprobe_opcode_t) * MAX_INSN_SIZE);
616 switch (p->ainsn.slot) {
618 dest->quad0.slot0 = src->quad0.slot0;
621 dest->quad1.slot1_p1 = src->quad1.slot1_p1;
624 dest->quad1.slot2 = src->quad1.slot2;
627 flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
630 void __kprobes arch_disarm_kprobe(struct kprobe *p)
632 unsigned long arm_addr;
633 bundle_t *src, *dest;
635 arm_addr = ((unsigned long)p->addr) & ~0xFUL;
636 dest = &((kprobe_opcode_t *)arm_addr)->bundle;
637 /* p->ainsn.insn contains the original unaltered kprobe_opcode_t */
638 src = &p->ainsn.insn->bundle;
639 switch (p->ainsn.slot) {
641 dest->quad0.slot0 = src->quad0.slot0;
644 dest->quad1.slot1_p1 = src->quad1.slot1_p1;
647 dest->quad1.slot2 = src->quad1.slot2;
650 flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
653 void __kprobes arch_remove_kprobe(struct kprobe *p)
656 free_insn_slot(p->ainsn.insn,
657 p->ainsn.inst_flag & INST_FLAG_BOOSTABLE);
658 p->ainsn.insn = NULL;
662 * We are resuming execution after a single step fault, so the pt_regs
663 * structure reflects the register state after we executed the instruction
664 * located in the kprobe (p->ainsn.insn->bundle). We still need to adjust
665 * the ip to point back to the original stack address. To set the IP address
666 * to original stack address, handle the case where we need to fixup the
667 * relative IP address and/or fixup branch register.
669 static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
671 unsigned long bundle_addr = (unsigned long) (&p->ainsn.insn->bundle);
672 unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL;
673 unsigned long template;
674 int slot = ((unsigned long)p->addr & 0xf);
676 template = p->ainsn.insn->bundle.quad0.template;
678 if (slot == 1 && bundle_encoding[template][1] == L)
681 if (p->ainsn.inst_flag & ~INST_FLAG_BOOSTABLE) {
683 if (p->ainsn.inst_flag & INST_FLAG_FIX_RELATIVE_IP_ADDR) {
684 /* Fix relative IP address */
685 regs->cr_iip = (regs->cr_iip - bundle_addr) +
689 if (p->ainsn.inst_flag & INST_FLAG_FIX_BRANCH_REG) {
691 * Fix target branch register, software convention is
692 * to use either b0 or b6 or b7, so just checking
693 * only those registers
695 switch (p->ainsn.target_br_reg) {
697 if ((regs->b0 == bundle_addr) ||
698 (regs->b0 == bundle_addr + 0x10)) {
699 regs->b0 = (regs->b0 - bundle_addr) +
704 if ((regs->b6 == bundle_addr) ||
705 (regs->b6 == bundle_addr + 0x10)) {
706 regs->b6 = (regs->b6 - bundle_addr) +
711 if ((regs->b7 == bundle_addr) ||
712 (regs->b7 == bundle_addr + 0x10)) {
713 regs->b7 = (regs->b7 - bundle_addr) +
723 if (regs->cr_iip == bundle_addr + 0x10) {
724 regs->cr_iip = resume_addr + 0x10;
727 if (regs->cr_iip == bundle_addr) {
728 regs->cr_iip = resume_addr;
733 /* Turn off Single Step bit */
734 ia64_psr(regs)->ss = 0;
737 static void __kprobes prepare_ss(struct kprobe *p, struct pt_regs *regs)
739 unsigned long bundle_addr = (unsigned long) &p->ainsn.insn->bundle;
740 unsigned long slot = (unsigned long)p->addr & 0xf;
742 /* single step inline if break instruction */
743 if (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)
744 regs->cr_iip = (unsigned long)p->addr & ~0xFULL;
746 regs->cr_iip = bundle_addr & ~0xFULL;
751 ia64_psr(regs)->ri = slot;
753 /* turn on single stepping */
754 ia64_psr(regs)->ss = 1;
757 static int __kprobes is_ia64_break_inst(struct pt_regs *regs)
759 unsigned int slot = ia64_psr(regs)->ri;
760 unsigned long *kprobe_addr = (unsigned long *)regs->cr_iip;
763 memcpy(&bundle, kprobe_addr, sizeof(bundle_t));
765 return __is_ia64_break_inst(&bundle, slot);
768 static int __kprobes pre_kprobes_handler(struct die_args *args)
772 struct pt_regs *regs = args->regs;
773 kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);
774 struct kprobe_ctlblk *kcb;
777 * We don't want to be preempted for the entire
778 * duration of kprobe processing
781 kcb = get_kprobe_ctlblk();
783 /* Handle recursion cases */
784 if (kprobe_running()) {
785 p = get_kprobe(addr);
787 if ((kcb->kprobe_status == KPROBE_HIT_SS) &&
788 (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)) {
789 ia64_psr(regs)->ss = 0;
792 /* We have reentered the pre_kprobe_handler(), since
793 * another probe was hit while within the handler.
794 * We here save the original kprobes variables and
795 * just single step on the instruction of the new probe
796 * without calling any user handlers.
798 save_previous_kprobe(kcb);
799 set_current_kprobe(p, kcb);
800 kprobes_inc_nmissed_count(p);
802 kcb->kprobe_status = KPROBE_REENTER;
804 } else if (!is_ia64_break_inst(regs)) {
805 /* The breakpoint instruction was removed by
806 * another cpu right after we hit, no further
807 * handling of this interrupt is appropriate
817 p = get_kprobe(addr);
819 if (!is_ia64_break_inst(regs)) {
821 * The breakpoint instruction was removed right
822 * after we hit it. Another cpu has removed
823 * either a probepoint or a debugger breakpoint
824 * at this address. In either case, no further
825 * handling of this interrupt is appropriate.
831 /* Not one of our break, let kernel handle it */
835 set_current_kprobe(p, kcb);
836 kcb->kprobe_status = KPROBE_HIT_ACTIVE;
838 if (p->pre_handler && p->pre_handler(p, regs)) {
839 reset_current_kprobe();
840 preempt_enable_no_resched();
844 #if !defined(CONFIG_PREEMPT)
845 if (p->ainsn.inst_flag == INST_FLAG_BOOSTABLE && !p->post_handler) {
846 /* Boost up -- we can execute copied instructions directly */
847 ia64_psr(regs)->ri = p->ainsn.slot;
848 regs->cr_iip = (unsigned long)&p->ainsn.insn->bundle & ~0xFULL;
849 /* turn single stepping off */
850 ia64_psr(regs)->ss = 0;
852 reset_current_kprobe();
853 preempt_enable_no_resched();
858 kcb->kprobe_status = KPROBE_HIT_SS;
862 preempt_enable_no_resched();
866 static int __kprobes post_kprobes_handler(struct pt_regs *regs)
868 struct kprobe *cur = kprobe_running();
869 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
874 if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
875 kcb->kprobe_status = KPROBE_HIT_SSDONE;
876 cur->post_handler(cur, regs, 0);
879 resume_execution(cur, regs);
881 /*Restore back the original saved kprobes variables and continue. */
882 if (kcb->kprobe_status == KPROBE_REENTER) {
883 restore_previous_kprobe(kcb);
886 reset_current_kprobe();
889 preempt_enable_no_resched();
893 int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
895 struct kprobe *cur = kprobe_running();
896 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
899 switch(kcb->kprobe_status) {
903 * We are here because the instruction being single
904 * stepped caused a page fault. We reset the current
905 * kprobe and the instruction pointer points back to
906 * the probe address and allow the page fault handler
907 * to continue as a normal page fault.
909 regs->cr_iip = ((unsigned long)cur->addr) & ~0xFULL;
910 ia64_psr(regs)->ri = ((unsigned long)cur->addr) & 0xf;
911 if (kcb->kprobe_status == KPROBE_REENTER)
912 restore_previous_kprobe(kcb);
914 reset_current_kprobe();
915 preempt_enable_no_resched();
917 case KPROBE_HIT_ACTIVE:
918 case KPROBE_HIT_SSDONE:
920 * We increment the nmissed count for accounting,
921 * we can also use npre/npostfault count for accounting
922 * these specific fault cases.
924 kprobes_inc_nmissed_count(cur);
927 * We come here because instructions in the pre/post
928 * handler caused the page_fault, this could happen
929 * if handler tries to access user space by
930 * copy_from_user(), get_user() etc. Let the
931 * user-specified handler try to fix it first.
933 if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
936 * In case the user-specified fault handler returned
937 * zero, try to fix up.
939 if (ia64_done_with_exception(regs))
943 * Let ia64_do_page_fault() fix it.
953 int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
954 unsigned long val, void *data)
956 struct die_args *args = (struct die_args *)data;
957 int ret = NOTIFY_DONE;
959 if (args->regs && user_mode(args->regs))
964 /* err is break number from ia64_bad_break() */
965 if ((args->err >> 12) == (__IA64_BREAK_KPROBE >> 12)
967 if (pre_kprobes_handler(args))
971 /* err is vector number from ia64_fault() */
973 if (post_kprobes_handler(args->regs))
982 unsigned long arch_deref_entry_point(void *entry)
984 return ((struct fnptr *)entry)->ip;
987 static struct kprobe trampoline_p = {
988 .pre_handler = trampoline_probe_handler
991 int __init arch_init_kprobes(void)
994 dereference_function_descriptor(kretprobe_trampoline);
995 return register_kprobe(&trampoline_p);
998 int __kprobes arch_trampoline_kprobe(struct kprobe *p)
1001 dereference_function_descriptor(kretprobe_trampoline))