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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Kernel Probes (KProbes)
4 * arch/ia64/kernel/kprobes.c
5 *
6 * Copyright (C) IBM Corporation, 2002, 2004
7 * Copyright (C) Intel Corporation, 2005
8 *
9 * 2005-Apr Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy
10 * <anil.s.keshavamurthy@intel.com> adapted from i386
11 */
12
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>
20
21#include <asm/pgtable.h>
22#include <asm/sections.h>
23#include <asm/exception.h>
24
25DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
26DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
27
28struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
29
30enum instruction_type {A, I, M, F, B, L, X, u};
31static enum instruction_type bundle_encoding[32][3] = {
32 { M, I, I }, /* 00 */
33 { M, I, I }, /* 01 */
34 { M, I, I }, /* 02 */
35 { M, I, I }, /* 03 */
36 { M, L, X }, /* 04 */
37 { M, L, X }, /* 05 */
38 { u, u, u }, /* 06 */
39 { u, u, u }, /* 07 */
40 { M, M, I }, /* 08 */
41 { M, M, I }, /* 09 */
42 { M, M, I }, /* 0A */
43 { M, M, I }, /* 0B */
44 { M, F, I }, /* 0C */
45 { M, F, I }, /* 0D */
46 { M, M, F }, /* 0E */
47 { M, M, F }, /* 0F */
48 { M, I, B }, /* 10 */
49 { M, I, B }, /* 11 */
50 { M, B, B }, /* 12 */
51 { M, B, B }, /* 13 */
52 { u, u, u }, /* 14 */
53 { u, u, u }, /* 15 */
54 { B, B, B }, /* 16 */
55 { B, B, B }, /* 17 */
56 { M, M, B }, /* 18 */
57 { M, M, B }, /* 19 */
58 { u, u, u }, /* 1A */
59 { u, u, u }, /* 1B */
60 { M, F, B }, /* 1C */
61 { M, F, B }, /* 1D */
62 { u, u, u }, /* 1E */
63 { u, u, u }, /* 1F */
64};
65
66/* Insert a long branch code */
67static void __kprobes set_brl_inst(void *from, void *to)
68{
69 s64 rel = ((s64) to - (s64) from) >> 4;
70 bundle_t *brl;
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);
78}
79
80/*
81 * In this function we check to see if the instruction
82 * is IP relative instruction and update the kprobe
83 * inst flag accordingly
84 */
85static void __kprobes update_kprobe_inst_flag(uint template, uint slot,
86 uint major_opcode,
87 unsigned long kprobe_inst,
88 struct kprobe *p)
89{
90 p->ainsn.inst_flag = 0;
91 p->ainsn.target_br_reg = 0;
92 p->ainsn.slot = slot;
93
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
98 */
99 if ((!major_opcode) && (!((kprobe_inst >> 27) & 0x1FF)) ) {
100 /* is a break instruction */
101 p->ainsn.inst_flag |= INST_FLAG_BREAK_INST;
102 return;
103 }
104
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);
110 break;
111 case IP_RELATIVE_PREDICT_OPCODE:
112 case IP_RELATIVE_BRANCH_OPCODE:
113 p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
114 break;
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);
119 break;
120 }
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);
126 break;
127 }
128 }
129 return;
130}
131
132/*
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
136 * with ctype as unc.
137 */
138static uint __kprobes is_cmp_ctype_unc_inst(uint template, uint slot,
139 uint major_opcode,
140 unsigned long kprobe_inst)
141{
142 cmp_inst_t cmp_inst;
143 uint ctype_unc = 0;
144
145 if (!((bundle_encoding[template][slot] == I) ||
146 (bundle_encoding[template][slot] == M)))
147 goto out;
148
149 if (!((major_opcode == 0xC) || (major_opcode == 0xD) ||
150 (major_opcode == 0xE)))
151 goto out;
152
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))
158 ctype_unc = 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))
162 ctype_unc = 1;
163 }
164out:
165 return ctype_unc;
166}
167
168/*
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
173 */
174static int __kprobes unsupported_inst(uint template, uint slot,
175 uint major_opcode,
176 unsigned long kprobe_inst,
177 unsigned long addr)
178{
179 int qp;
180
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);
187 return -EINVAL;
188
189 }
190 qp = 0;
191 }
192 else if (bundle_encoding[template][slot] == I) {
193 if (major_opcode == 0) {
194 /*
195 * Check for Integer speculation instruction
196 * - Bit 33-35 to be equal to 0x1
197 */
198 if (((kprobe_inst >> 33) & 0x7) == 1) {
199 printk(KERN_WARNING
200 "Kprobes on speculation inst at <0x%lx> not supported\n",
201 addr);
202 return -EINVAL;
203 }
204 /*
205 * IP relative mov instruction
206 * - Bit 27-35 to be equal to 0x30
207 */
208 if (((kprobe_inst >> 27) & 0x1FF) == 0x30) {
209 printk(KERN_WARNING
210 "Kprobes on \"mov r1=ip\" at <0x%lx> not supported\n",
211 addr);
212 return -EINVAL;
213
214 }
215 }
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
221 */
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);
226 return -EINVAL;
227 }
228 qp = 0;
229 }
230 }
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");
236 return -EINVAL;
237 }
238 else if (major_opcode == 2) {
239 /* Indirect Predict, major code is 2
240 * bit 27-32 to be equal to 10 or 11
241 */
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");
246 return -EINVAL;
247 }
248 }
249 }
250 /* kernel does not use float instruction, here for safety kprobe
251 * will judge whether it is fcmp/flass/float approximation instruction
252 */
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);
261 return -EINVAL;
262
263 }
264 qp = 0;
265 }
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",
272 addr);
273 return -EINVAL;
274 }
275 qp = 0;
276 }
277 }
278 return qp;
279}
280
281/*
282 * In this function we override the bundle with
283 * the break instruction at the given slot.
284 */
285static void __kprobes prepare_break_inst(uint template, uint slot,
286 uint major_opcode,
287 unsigned long kprobe_inst,
288 struct kprobe *p,
289 int qp)
290{
291 unsigned long break_inst = BREAK_INST;
292 bundle_t *bundle = &p->opcode.bundle;
293
294 /*
295 * Copy the original kprobe_inst qualifying predicate(qp)
296 * to the break instruction
297 */
298 break_inst |= qp;
299
300 switch (slot) {
301 case 0:
302 bundle->quad0.slot0 = break_inst;
303 break;
304 case 1:
305 bundle->quad0.slot1_p0 = break_inst;
306 bundle->quad1.slot1_p1 = break_inst >> (64-46);
307 break;
308 case 2:
309 bundle->quad1.slot2 = break_inst;
310 break;
311 }
312
313 /*
314 * Update the instruction flag, so that we can
315 * emulate the instruction properly after we
316 * single step on original instruction
317 */
318 update_kprobe_inst_flag(template, slot, major_opcode, kprobe_inst, p);
319}
320
321static void __kprobes get_kprobe_inst(bundle_t *bundle, uint slot,
322 unsigned long *kprobe_inst, uint *major_opcode)
323{
324 unsigned long kprobe_inst_p0, kprobe_inst_p1;
325 unsigned int template;
326
327 template = bundle->quad0.template;
328
329 switch (slot) {
330 case 0:
331 *major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT);
332 *kprobe_inst = bundle->quad0.slot0;
333 break;
334 case 1:
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));
339 break;
340 case 2:
341 *major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT);
342 *kprobe_inst = bundle->quad1.slot2;
343 break;
344 }
345}
346
347/* Returns non-zero if the addr is in the Interrupt Vector Table */
348static int __kprobes in_ivt_functions(unsigned long addr)
349{
350 return (addr >= (unsigned long)__start_ivt_text
351 && addr < (unsigned long)__end_ivt_text);
352}
353
354static int __kprobes valid_kprobe_addr(int template, int slot,
355 unsigned long addr)
356{
357 if ((slot > 2) || ((bundle_encoding[template][1] == L) && slot > 1)) {
358 printk(KERN_WARNING "Attempting to insert unaligned kprobe "
359 "at 0x%lx\n", addr);
360 return -EINVAL;
361 }
362
363 if (in_ivt_functions(addr)) {
364 printk(KERN_WARNING "Kprobes can't be inserted inside "
365 "IVT functions at 0x%lx\n", addr);
366 return -EINVAL;
367 }
368
369 return 0;
370}
371
372static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
373{
374 unsigned int i;
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;
378}
379
380static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
381{
382 unsigned int i;
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);
387}
388
389static void __kprobes set_current_kprobe(struct kprobe *p,
390 struct kprobe_ctlblk *kcb)
391{
392 __this_cpu_write(current_kprobe, p);
393}
394
395static void kretprobe_trampoline(void)
396{
397}
398
399/*
400 * At this point the target function has been tricked into
401 * returning into our trampoline. Lookup the associated instance
402 * and then:
403 * - call the handler function
404 * - cleanup by marking the instance as unused
405 * - long jump back to the original return address
406 */
407int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
408{
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 ((struct fnptr *)kretprobe_trampoline)->ip;
415
416 INIT_HLIST_HEAD(&empty_rp);
417 kretprobe_hash_lock(current, &head, &flags);
418
419 /*
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.
424 *
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
431 */
432 hlist_for_each_entry_safe(ri, tmp, head, hlist) {
433 if (ri->task != current)
434 /* another task is sharing our hash bucket */
435 continue;
436
437 orig_ret_address = (unsigned long)ri->ret_addr;
438 if (orig_ret_address != trampoline_address)
439 /*
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
443 */
444 break;
445 }
446
447 regs->cr_iip = orig_ret_address;
448
449 hlist_for_each_entry_safe(ri, tmp, head, hlist) {
450 if (ri->task != current)
451 /* another task is sharing our hash bucket */
452 continue;
453
454 if (ri->rp && ri->rp->handler)
455 ri->rp->handler(ri, regs);
456
457 orig_ret_address = (unsigned long)ri->ret_addr;
458 recycle_rp_inst(ri, &empty_rp);
459
460 if (orig_ret_address != trampoline_address)
461 /*
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
465 */
466 break;
467 }
468 kretprobe_assert(ri, orig_ret_address, trampoline_address);
469
470 kretprobe_hash_unlock(current, &flags);
471
472 hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
473 hlist_del(&ri->hlist);
474 kfree(ri);
475 }
476 /*
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)
480 */
481 return 1;
482}
483
484void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
485 struct pt_regs *regs)
486{
487 ri->ret_addr = (kprobe_opcode_t *)regs->b0;
488
489 /* Replace the return addr with trampoline addr */
490 regs->b0 = ((struct fnptr *)kretprobe_trampoline)->ip;
491}
492
493/* Check the instruction in the slot is break */
494static int __kprobes __is_ia64_break_inst(bundle_t *bundle, uint slot)
495{
496 unsigned int major_opcode;
497 unsigned int template = bundle->quad0.template;
498 unsigned long kprobe_inst;
499
500 /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
501 if (slot == 1 && bundle_encoding[template][1] == L)
502 slot++;
503
504 /* Get Kprobe probe instruction at given slot*/
505 get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
506
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
511 */
512 if (major_opcode || ((kprobe_inst >> 27) & 0x1FF)) {
513 /* Not a break instruction */
514 return 0;
515 }
516
517 /* Is a break instruction */
518 return 1;
519}
520
521/*
522 * In this function, we check whether the target bundle modifies IP or
523 * it triggers an exception. If so, it cannot be boostable.
524 */
525static int __kprobes can_boost(bundle_t *bundle, uint slot,
526 unsigned long bundle_addr)
527{
528 unsigned int template = bundle->quad0.template;
529
530 do {
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);
535 template &= 0x1e;
536 if (template >= 0x10 /* including B unit */ ||
537 template == 0x04 /* including X unit */ ||
538 template == 0x06) /* undefined */
539 return 0;
540
541 return 1;
542}
543
544/* Prepare long jump bundle and disables other boosters if need */
545static void __kprobes prepare_booster(struct kprobe *p)
546{
547 unsigned long addr = (unsigned long)p->addr & ~0xFULL;
548 unsigned int slot = (unsigned long)p->addr & 0xf;
549 struct kprobe *other_kp;
550
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;
554 }
555
556 /* disables boosters in previous slots */
557 for (; addr < (unsigned long)p->addr; addr++) {
558 other_kp = get_kprobe((void *)addr);
559 if (other_kp)
560 other_kp->ainsn.inst_flag &= ~INST_FLAG_BOOSTABLE;
561 }
562}
563
564int __kprobes arch_prepare_kprobe(struct kprobe *p)
565{
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;
570 bundle_t *bundle;
571 int qp;
572
573 bundle = &((kprobe_opcode_t *)kprobe_addr)->bundle;
574 template = bundle->quad0.template;
575
576 if(valid_kprobe_addr(template, slot, addr))
577 return -EINVAL;
578
579 /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
580 if (slot == 1 && bundle_encoding[template][1] == L)
581 slot++;
582
583 /* Get kprobe_inst and major_opcode from the bundle */
584 get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
585
586 qp = unsupported_inst(template, slot, major_opcode, kprobe_inst, addr);
587 if (qp < 0)
588 return -EINVAL;
589
590 p->ainsn.insn = get_insn_slot();
591 if (!p->ainsn.insn)
592 return -ENOMEM;
593 memcpy(&p->opcode, kprobe_addr, sizeof(kprobe_opcode_t));
594 memcpy(p->ainsn.insn, kprobe_addr, sizeof(kprobe_opcode_t));
595
596 prepare_break_inst(template, slot, major_opcode, kprobe_inst, p, qp);
597
598 prepare_booster(p);
599
600 return 0;
601}
602
603void __kprobes arch_arm_kprobe(struct kprobe *p)
604{
605 unsigned long arm_addr;
606 bundle_t *src, *dest;
607
608 arm_addr = ((unsigned long)p->addr) & ~0xFUL;
609 dest = &((kprobe_opcode_t *)arm_addr)->bundle;
610 src = &p->opcode.bundle;
611
612 flush_icache_range((unsigned long)p->ainsn.insn,
613 (unsigned long)p->ainsn.insn +
614 sizeof(kprobe_opcode_t) * MAX_INSN_SIZE);
615
616 switch (p->ainsn.slot) {
617 case 0:
618 dest->quad0.slot0 = src->quad0.slot0;
619 break;
620 case 1:
621 dest->quad1.slot1_p1 = src->quad1.slot1_p1;
622 break;
623 case 2:
624 dest->quad1.slot2 = src->quad1.slot2;
625 break;
626 }
627 flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
628}
629
630void __kprobes arch_disarm_kprobe(struct kprobe *p)
631{
632 unsigned long arm_addr;
633 bundle_t *src, *dest;
634
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) {
640 case 0:
641 dest->quad0.slot0 = src->quad0.slot0;
642 break;
643 case 1:
644 dest->quad1.slot1_p1 = src->quad1.slot1_p1;
645 break;
646 case 2:
647 dest->quad1.slot2 = src->quad1.slot2;
648 break;
649 }
650 flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
651}
652
653void __kprobes arch_remove_kprobe(struct kprobe *p)
654{
655 if (p->ainsn.insn) {
656 free_insn_slot(p->ainsn.insn,
657 p->ainsn.inst_flag & INST_FLAG_BOOSTABLE);
658 p->ainsn.insn = NULL;
659 }
660}
661/*
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.
668 */
669static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
670{
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);
675
676 template = p->ainsn.insn->bundle.quad0.template;
677
678 if (slot == 1 && bundle_encoding[template][1] == L)
679 slot = 2;
680
681 if (p->ainsn.inst_flag & ~INST_FLAG_BOOSTABLE) {
682
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) +
686 resume_addr;
687 }
688
689 if (p->ainsn.inst_flag & INST_FLAG_FIX_BRANCH_REG) {
690 /*
691 * Fix target branch register, software convention is
692 * to use either b0 or b6 or b7, so just checking
693 * only those registers
694 */
695 switch (p->ainsn.target_br_reg) {
696 case 0:
697 if ((regs->b0 == bundle_addr) ||
698 (regs->b0 == bundle_addr + 0x10)) {
699 regs->b0 = (regs->b0 - bundle_addr) +
700 resume_addr;
701 }
702 break;
703 case 6:
704 if ((regs->b6 == bundle_addr) ||
705 (regs->b6 == bundle_addr + 0x10)) {
706 regs->b6 = (regs->b6 - bundle_addr) +
707 resume_addr;
708 }
709 break;
710 case 7:
711 if ((regs->b7 == bundle_addr) ||
712 (regs->b7 == bundle_addr + 0x10)) {
713 regs->b7 = (regs->b7 - bundle_addr) +
714 resume_addr;
715 }
716 break;
717 } /* end switch */
718 }
719 goto turn_ss_off;
720 }
721
722 if (slot == 2) {
723 if (regs->cr_iip == bundle_addr + 0x10) {
724 regs->cr_iip = resume_addr + 0x10;
725 }
726 } else {
727 if (regs->cr_iip == bundle_addr) {
728 regs->cr_iip = resume_addr;
729 }
730 }
731
732turn_ss_off:
733 /* Turn off Single Step bit */
734 ia64_psr(regs)->ss = 0;
735}
736
737static void __kprobes prepare_ss(struct kprobe *p, struct pt_regs *regs)
738{
739 unsigned long bundle_addr = (unsigned long) &p->ainsn.insn->bundle;
740 unsigned long slot = (unsigned long)p->addr & 0xf;
741
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;
745 else
746 regs->cr_iip = bundle_addr & ~0xFULL;
747
748 if (slot > 2)
749 slot = 0;
750
751 ia64_psr(regs)->ri = slot;
752
753 /* turn on single stepping */
754 ia64_psr(regs)->ss = 1;
755}
756
757static int __kprobes is_ia64_break_inst(struct pt_regs *regs)
758{
759 unsigned int slot = ia64_psr(regs)->ri;
760 unsigned long *kprobe_addr = (unsigned long *)regs->cr_iip;
761 bundle_t bundle;
762
763 memcpy(&bundle, kprobe_addr, sizeof(bundle_t));
764
765 return __is_ia64_break_inst(&bundle, slot);
766}
767
768static int __kprobes pre_kprobes_handler(struct die_args *args)
769{
770 struct kprobe *p;
771 int ret = 0;
772 struct pt_regs *regs = args->regs;
773 kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);
774 struct kprobe_ctlblk *kcb;
775
776 /*
777 * We don't want to be preempted for the entire
778 * duration of kprobe processing
779 */
780 preempt_disable();
781 kcb = get_kprobe_ctlblk();
782
783 /* Handle recursion cases */
784 if (kprobe_running()) {
785 p = get_kprobe(addr);
786 if (p) {
787 if ((kcb->kprobe_status == KPROBE_HIT_SS) &&
788 (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)) {
789 ia64_psr(regs)->ss = 0;
790 goto no_kprobe;
791 }
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.
797 */
798 save_previous_kprobe(kcb);
799 set_current_kprobe(p, kcb);
800 kprobes_inc_nmissed_count(p);
801 prepare_ss(p, regs);
802 kcb->kprobe_status = KPROBE_REENTER;
803 return 1;
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
808 */
809 ret = 1;
810 goto no_kprobe;
811 } else {
812 /* Not our break */
813 goto no_kprobe;
814 }
815 }
816
817 p = get_kprobe(addr);
818 if (!p) {
819 if (!is_ia64_break_inst(regs)) {
820 /*
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.
826 */
827 ret = 1;
828
829 }
830
831 /* Not one of our break, let kernel handle it */
832 goto no_kprobe;
833 }
834
835 set_current_kprobe(p, kcb);
836 kcb->kprobe_status = KPROBE_HIT_ACTIVE;
837
838 if (p->pre_handler && p->pre_handler(p, regs)) {
839 reset_current_kprobe();
840 preempt_enable_no_resched();
841 return 1;
842 }
843
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;
851
852 reset_current_kprobe();
853 preempt_enable_no_resched();
854 return 1;
855 }
856#endif
857 prepare_ss(p, regs);
858 kcb->kprobe_status = KPROBE_HIT_SS;
859 return 1;
860
861no_kprobe:
862 preempt_enable_no_resched();
863 return ret;
864}
865
866static int __kprobes post_kprobes_handler(struct pt_regs *regs)
867{
868 struct kprobe *cur = kprobe_running();
869 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
870
871 if (!cur)
872 return 0;
873
874 if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
875 kcb->kprobe_status = KPROBE_HIT_SSDONE;
876 cur->post_handler(cur, regs, 0);
877 }
878
879 resume_execution(cur, regs);
880
881 /*Restore back the original saved kprobes variables and continue. */
882 if (kcb->kprobe_status == KPROBE_REENTER) {
883 restore_previous_kprobe(kcb);
884 goto out;
885 }
886 reset_current_kprobe();
887
888out:
889 preempt_enable_no_resched();
890 return 1;
891}
892
893int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
894{
895 struct kprobe *cur = kprobe_running();
896 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
897
898
899 switch(kcb->kprobe_status) {
900 case KPROBE_HIT_SS:
901 case KPROBE_REENTER:
902 /*
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.
908 */
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);
913 else
914 reset_current_kprobe();
915 preempt_enable_no_resched();
916 break;
917 case KPROBE_HIT_ACTIVE:
918 case KPROBE_HIT_SSDONE:
919 /*
920 * We increment the nmissed count for accounting,
921 * we can also use npre/npostfault count for accounting
922 * these specific fault cases.
923 */
924 kprobes_inc_nmissed_count(cur);
925
926 /*
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.
932 */
933 if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
934 return 1;
935 /*
936 * In case the user-specified fault handler returned
937 * zero, try to fix up.
938 */
939 if (ia64_done_with_exception(regs))
940 return 1;
941
942 /*
943 * Let ia64_do_page_fault() fix it.
944 */
945 break;
946 default:
947 break;
948 }
949
950 return 0;
951}
952
953int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
954 unsigned long val, void *data)
955{
956 struct die_args *args = (struct die_args *)data;
957 int ret = NOTIFY_DONE;
958
959 if (args->regs && user_mode(args->regs))
960 return ret;
961
962 switch(val) {
963 case DIE_BREAK:
964 /* err is break number from ia64_bad_break() */
965 if ((args->err >> 12) == (__IA64_BREAK_KPROBE >> 12)
966 || args->err == 0)
967 if (pre_kprobes_handler(args))
968 ret = NOTIFY_STOP;
969 break;
970 case DIE_FAULT:
971 /* err is vector number from ia64_fault() */
972 if (args->err == 36)
973 if (post_kprobes_handler(args->regs))
974 ret = NOTIFY_STOP;
975 break;
976 default:
977 break;
978 }
979 return ret;
980}
981
982unsigned long arch_deref_entry_point(void *entry)
983{
984 return ((struct fnptr *)entry)->ip;
985}
986
987static struct kprobe trampoline_p = {
988 .pre_handler = trampoline_probe_handler
989};
990
991int __init arch_init_kprobes(void)
992{
993 trampoline_p.addr =
994 (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip;
995 return register_kprobe(&trampoline_p);
996}
997
998int __kprobes arch_trampoline_kprobe(struct kprobe *p)
999{
1000 if (p->addr ==
1001 (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip)
1002 return 1;
1003
1004 return 0;
1005}