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1/*
2 * Kernel Probes (KProbes)
3 * arch/ia64/kernel/kprobes.c
4 *
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.
9 *
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.
14 *
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.
18 *
19 * Copyright (C) IBM Corporation, 2002, 2004
20 * Copyright (C) Intel Corporation, 2005
21 *
22 * 2005-Apr Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy
23 * <anil.s.keshavamurthy@intel.com> adapted from i386
24 */
25
26#include <linux/kprobes.h>
27#include <linux/ptrace.h>
28#include <linux/string.h>
29#include <linux/slab.h>
30#include <linux/preempt.h>
31#include <linux/moduleloader.h>
32#include <linux/kdebug.h>
33
34#include <asm/pgtable.h>
35#include <asm/sections.h>
36#include <asm/uaccess.h>
37
38extern void jprobe_inst_return(void);
39
40DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
41DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
42
43struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
44
45enum instruction_type {A, I, M, F, B, L, X, u};
46static enum instruction_type bundle_encoding[32][3] = {
47 { M, I, I }, /* 00 */
48 { M, I, I }, /* 01 */
49 { M, I, I }, /* 02 */
50 { M, I, I }, /* 03 */
51 { M, L, X }, /* 04 */
52 { M, L, X }, /* 05 */
53 { u, u, u }, /* 06 */
54 { u, u, u }, /* 07 */
55 { M, M, I }, /* 08 */
56 { M, M, I }, /* 09 */
57 { M, M, I }, /* 0A */
58 { M, M, I }, /* 0B */
59 { M, F, I }, /* 0C */
60 { M, F, I }, /* 0D */
61 { M, M, F }, /* 0E */
62 { M, M, F }, /* 0F */
63 { M, I, B }, /* 10 */
64 { M, I, B }, /* 11 */
65 { M, B, B }, /* 12 */
66 { M, B, B }, /* 13 */
67 { u, u, u }, /* 14 */
68 { u, u, u }, /* 15 */
69 { B, B, B }, /* 16 */
70 { B, B, B }, /* 17 */
71 { M, M, B }, /* 18 */
72 { M, M, B }, /* 19 */
73 { u, u, u }, /* 1A */
74 { u, u, u }, /* 1B */
75 { M, F, B }, /* 1C */
76 { M, F, B }, /* 1D */
77 { u, u, u }, /* 1E */
78 { u, u, u }, /* 1F */
79};
80
81/* Insert a long branch code */
82static void __kprobes set_brl_inst(void *from, void *to)
83{
84 s64 rel = ((s64) to - (s64) from) >> 4;
85 bundle_t *brl;
86 brl = (bundle_t *) ((u64) from & ~0xf);
87 brl->quad0.template = 0x05; /* [MLX](stop) */
88 brl->quad0.slot0 = NOP_M_INST; /* nop.m 0x0 */
89 brl->quad0.slot1_p0 = ((rel >> 20) & 0x7fffffffff) << 2;
90 brl->quad1.slot1_p1 = (((rel >> 20) & 0x7fffffffff) << 2) >> (64 - 46);
91 /* brl.cond.sptk.many.clr rel<<4 (qp=0) */
92 brl->quad1.slot2 = BRL_INST(rel >> 59, rel & 0xfffff);
93}
94
95/*
96 * In this function we check to see if the instruction
97 * is IP relative instruction and update the kprobe
98 * inst flag accordingly
99 */
100static void __kprobes update_kprobe_inst_flag(uint template, uint slot,
101 uint major_opcode,
102 unsigned long kprobe_inst,
103 struct kprobe *p)
104{
105 p->ainsn.inst_flag = 0;
106 p->ainsn.target_br_reg = 0;
107 p->ainsn.slot = slot;
108
109 /* Check for Break instruction
110 * Bits 37:40 Major opcode to be zero
111 * Bits 27:32 X6 to be zero
112 * Bits 32:35 X3 to be zero
113 */
114 if ((!major_opcode) && (!((kprobe_inst >> 27) & 0x1FF)) ) {
115 /* is a break instruction */
116 p->ainsn.inst_flag |= INST_FLAG_BREAK_INST;
117 return;
118 }
119
120 if (bundle_encoding[template][slot] == B) {
121 switch (major_opcode) {
122 case INDIRECT_CALL_OPCODE:
123 p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
124 p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
125 break;
126 case IP_RELATIVE_PREDICT_OPCODE:
127 case IP_RELATIVE_BRANCH_OPCODE:
128 p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
129 break;
130 case IP_RELATIVE_CALL_OPCODE:
131 p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
132 p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
133 p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
134 break;
135 }
136 } else if (bundle_encoding[template][slot] == X) {
137 switch (major_opcode) {
138 case LONG_CALL_OPCODE:
139 p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
140 p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
141 break;
142 }
143 }
144 return;
145}
146
147/*
148 * In this function we check to see if the instruction
149 * (qp) cmpx.crel.ctype p1,p2=r2,r3
150 * on which we are inserting kprobe is cmp instruction
151 * with ctype as unc.
152 */
153static uint __kprobes is_cmp_ctype_unc_inst(uint template, uint slot,
154 uint major_opcode,
155 unsigned long kprobe_inst)
156{
157 cmp_inst_t cmp_inst;
158 uint ctype_unc = 0;
159
160 if (!((bundle_encoding[template][slot] == I) ||
161 (bundle_encoding[template][slot] == M)))
162 goto out;
163
164 if (!((major_opcode == 0xC) || (major_opcode == 0xD) ||
165 (major_opcode == 0xE)))
166 goto out;
167
168 cmp_inst.l = kprobe_inst;
169 if ((cmp_inst.f.x2 == 0) || (cmp_inst.f.x2 == 1)) {
170 /* Integer compare - Register Register (A6 type)*/
171 if ((cmp_inst.f.tb == 0) && (cmp_inst.f.ta == 0)
172 &&(cmp_inst.f.c == 1))
173 ctype_unc = 1;
174 } else if ((cmp_inst.f.x2 == 2)||(cmp_inst.f.x2 == 3)) {
175 /* Integer compare - Immediate Register (A8 type)*/
176 if ((cmp_inst.f.ta == 0) &&(cmp_inst.f.c == 1))
177 ctype_unc = 1;
178 }
179out:
180 return ctype_unc;
181}
182
183/*
184 * In this function we check to see if the instruction
185 * on which we are inserting kprobe is supported.
186 * Returns qp value if supported
187 * Returns -EINVAL if unsupported
188 */
189static int __kprobes unsupported_inst(uint template, uint slot,
190 uint major_opcode,
191 unsigned long kprobe_inst,
192 unsigned long addr)
193{
194 int qp;
195
196 qp = kprobe_inst & 0x3f;
197 if (is_cmp_ctype_unc_inst(template, slot, major_opcode, kprobe_inst)) {
198 if (slot == 1 && qp) {
199 printk(KERN_WARNING "Kprobes on cmp unc "
200 "instruction on slot 1 at <0x%lx> "
201 "is not supported\n", addr);
202 return -EINVAL;
203
204 }
205 qp = 0;
206 }
207 else if (bundle_encoding[template][slot] == I) {
208 if (major_opcode == 0) {
209 /*
210 * Check for Integer speculation instruction
211 * - Bit 33-35 to be equal to 0x1
212 */
213 if (((kprobe_inst >> 33) & 0x7) == 1) {
214 printk(KERN_WARNING
215 "Kprobes on speculation inst at <0x%lx> not supported\n",
216 addr);
217 return -EINVAL;
218 }
219 /*
220 * IP relative mov instruction
221 * - Bit 27-35 to be equal to 0x30
222 */
223 if (((kprobe_inst >> 27) & 0x1FF) == 0x30) {
224 printk(KERN_WARNING
225 "Kprobes on \"mov r1=ip\" at <0x%lx> not supported\n",
226 addr);
227 return -EINVAL;
228
229 }
230 }
231 else if ((major_opcode == 5) && !(kprobe_inst & (0xFUl << 33)) &&
232 (kprobe_inst & (0x1UL << 12))) {
233 /* test bit instructions, tbit,tnat,tf
234 * bit 33-36 to be equal to 0
235 * bit 12 to be equal to 1
236 */
237 if (slot == 1 && qp) {
238 printk(KERN_WARNING "Kprobes on test bit "
239 "instruction on slot at <0x%lx> "
240 "is not supported\n", addr);
241 return -EINVAL;
242 }
243 qp = 0;
244 }
245 }
246 else if (bundle_encoding[template][slot] == B) {
247 if (major_opcode == 7) {
248 /* IP-Relative Predict major code is 7 */
249 printk(KERN_WARNING "Kprobes on IP-Relative"
250 "Predict is not supported\n");
251 return -EINVAL;
252 }
253 else if (major_opcode == 2) {
254 /* Indirect Predict, major code is 2
255 * bit 27-32 to be equal to 10 or 11
256 */
257 int x6=(kprobe_inst >> 27) & 0x3F;
258 if ((x6 == 0x10) || (x6 == 0x11)) {
259 printk(KERN_WARNING "Kprobes on "
260 "Indirect Predict is not supported\n");
261 return -EINVAL;
262 }
263 }
264 }
265 /* kernel does not use float instruction, here for safety kprobe
266 * will judge whether it is fcmp/flass/float approximation instruction
267 */
268 else if (unlikely(bundle_encoding[template][slot] == F)) {
269 if ((major_opcode == 4 || major_opcode == 5) &&
270 (kprobe_inst & (0x1 << 12))) {
271 /* fcmp/fclass unc instruction */
272 if (slot == 1 && qp) {
273 printk(KERN_WARNING "Kprobes on fcmp/fclass "
274 "instruction on slot at <0x%lx> "
275 "is not supported\n", addr);
276 return -EINVAL;
277
278 }
279 qp = 0;
280 }
281 if ((major_opcode == 0 || major_opcode == 1) &&
282 (kprobe_inst & (0x1UL << 33))) {
283 /* float Approximation instruction */
284 if (slot == 1 && qp) {
285 printk(KERN_WARNING "Kprobes on float Approx "
286 "instr at <0x%lx> is not supported\n",
287 addr);
288 return -EINVAL;
289 }
290 qp = 0;
291 }
292 }
293 return qp;
294}
295
296/*
297 * In this function we override the bundle with
298 * the break instruction at the given slot.
299 */
300static void __kprobes prepare_break_inst(uint template, uint slot,
301 uint major_opcode,
302 unsigned long kprobe_inst,
303 struct kprobe *p,
304 int qp)
305{
306 unsigned long break_inst = BREAK_INST;
307 bundle_t *bundle = &p->opcode.bundle;
308
309 /*
310 * Copy the original kprobe_inst qualifying predicate(qp)
311 * to the break instruction
312 */
313 break_inst |= qp;
314
315 switch (slot) {
316 case 0:
317 bundle->quad0.slot0 = break_inst;
318 break;
319 case 1:
320 bundle->quad0.slot1_p0 = break_inst;
321 bundle->quad1.slot1_p1 = break_inst >> (64-46);
322 break;
323 case 2:
324 bundle->quad1.slot2 = break_inst;
325 break;
326 }
327
328 /*
329 * Update the instruction flag, so that we can
330 * emulate the instruction properly after we
331 * single step on original instruction
332 */
333 update_kprobe_inst_flag(template, slot, major_opcode, kprobe_inst, p);
334}
335
336static void __kprobes get_kprobe_inst(bundle_t *bundle, uint slot,
337 unsigned long *kprobe_inst, uint *major_opcode)
338{
339 unsigned long kprobe_inst_p0, kprobe_inst_p1;
340 unsigned int template;
341
342 template = bundle->quad0.template;
343
344 switch (slot) {
345 case 0:
346 *major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT);
347 *kprobe_inst = bundle->quad0.slot0;
348 break;
349 case 1:
350 *major_opcode = (bundle->quad1.slot1_p1 >> SLOT1_p1_OPCODE_SHIFT);
351 kprobe_inst_p0 = bundle->quad0.slot1_p0;
352 kprobe_inst_p1 = bundle->quad1.slot1_p1;
353 *kprobe_inst = kprobe_inst_p0 | (kprobe_inst_p1 << (64-46));
354 break;
355 case 2:
356 *major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT);
357 *kprobe_inst = bundle->quad1.slot2;
358 break;
359 }
360}
361
362/* Returns non-zero if the addr is in the Interrupt Vector Table */
363static int __kprobes in_ivt_functions(unsigned long addr)
364{
365 return (addr >= (unsigned long)__start_ivt_text
366 && addr < (unsigned long)__end_ivt_text);
367}
368
369static int __kprobes valid_kprobe_addr(int template, int slot,
370 unsigned long addr)
371{
372 if ((slot > 2) || ((bundle_encoding[template][1] == L) && slot > 1)) {
373 printk(KERN_WARNING "Attempting to insert unaligned kprobe "
374 "at 0x%lx\n", addr);
375 return -EINVAL;
376 }
377
378 if (in_ivt_functions(addr)) {
379 printk(KERN_WARNING "Kprobes can't be inserted inside "
380 "IVT functions at 0x%lx\n", addr);
381 return -EINVAL;
382 }
383
384 return 0;
385}
386
387static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
388{
389 unsigned int i;
390 i = atomic_add_return(1, &kcb->prev_kprobe_index);
391 kcb->prev_kprobe[i-1].kp = kprobe_running();
392 kcb->prev_kprobe[i-1].status = kcb->kprobe_status;
393}
394
395static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
396{
397 unsigned int i;
398 i = atomic_read(&kcb->prev_kprobe_index);
399 __get_cpu_var(current_kprobe) = kcb->prev_kprobe[i-1].kp;
400 kcb->kprobe_status = kcb->prev_kprobe[i-1].status;
401 atomic_sub(1, &kcb->prev_kprobe_index);
402}
403
404static void __kprobes set_current_kprobe(struct kprobe *p,
405 struct kprobe_ctlblk *kcb)
406{
407 __get_cpu_var(current_kprobe) = p;
408}
409
410static void kretprobe_trampoline(void)
411{
412}
413
414/*
415 * At this point the target function has been tricked into
416 * returning into our trampoline. Lookup the associated instance
417 * and then:
418 * - call the handler function
419 * - cleanup by marking the instance as unused
420 * - long jump back to the original return address
421 */
422int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
423{
424 struct kretprobe_instance *ri = NULL;
425 struct hlist_head *head, empty_rp;
426 struct hlist_node *node, *tmp;
427 unsigned long flags, orig_ret_address = 0;
428 unsigned long trampoline_address =
429 ((struct fnptr *)kretprobe_trampoline)->ip;
430
431 INIT_HLIST_HEAD(&empty_rp);
432 kretprobe_hash_lock(current, &head, &flags);
433
434 /*
435 * It is possible to have multiple instances associated with a given
436 * task either because an multiple functions in the call path
437 * have a return probe installed on them, and/or more than one return
438 * return probe was registered for a target function.
439 *
440 * We can handle this because:
441 * - instances are always inserted at the head of the list
442 * - when multiple return probes are registered for the same
443 * function, the first instance's ret_addr will point to the
444 * real return address, and all the rest will point to
445 * kretprobe_trampoline
446 */
447 hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
448 if (ri->task != current)
449 /* another task is sharing our hash bucket */
450 continue;
451
452 orig_ret_address = (unsigned long)ri->ret_addr;
453 if (orig_ret_address != trampoline_address)
454 /*
455 * This is the real return address. Any other
456 * instances associated with this task are for
457 * other calls deeper on the call stack
458 */
459 break;
460 }
461
462 regs->cr_iip = orig_ret_address;
463
464 hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
465 if (ri->task != current)
466 /* another task is sharing our hash bucket */
467 continue;
468
469 if (ri->rp && ri->rp->handler)
470 ri->rp->handler(ri, regs);
471
472 orig_ret_address = (unsigned long)ri->ret_addr;
473 recycle_rp_inst(ri, &empty_rp);
474
475 if (orig_ret_address != trampoline_address)
476 /*
477 * This is the real return address. Any other
478 * instances associated with this task are for
479 * other calls deeper on the call stack
480 */
481 break;
482 }
483
484 kretprobe_assert(ri, orig_ret_address, trampoline_address);
485
486 reset_current_kprobe();
487 kretprobe_hash_unlock(current, &flags);
488 preempt_enable_no_resched();
489
490 hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
491 hlist_del(&ri->hlist);
492 kfree(ri);
493 }
494 /*
495 * By returning a non-zero value, we are telling
496 * kprobe_handler() that we don't want the post_handler
497 * to run (and have re-enabled preemption)
498 */
499 return 1;
500}
501
502void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
503 struct pt_regs *regs)
504{
505 ri->ret_addr = (kprobe_opcode_t *)regs->b0;
506
507 /* Replace the return addr with trampoline addr */
508 regs->b0 = ((struct fnptr *)kretprobe_trampoline)->ip;
509}
510
511/* Check the instruction in the slot is break */
512static int __kprobes __is_ia64_break_inst(bundle_t *bundle, uint slot)
513{
514 unsigned int major_opcode;
515 unsigned int template = bundle->quad0.template;
516 unsigned long kprobe_inst;
517
518 /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
519 if (slot == 1 && bundle_encoding[template][1] == L)
520 slot++;
521
522 /* Get Kprobe probe instruction at given slot*/
523 get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
524
525 /* For break instruction,
526 * Bits 37:40 Major opcode to be zero
527 * Bits 27:32 X6 to be zero
528 * Bits 32:35 X3 to be zero
529 */
530 if (major_opcode || ((kprobe_inst >> 27) & 0x1FF)) {
531 /* Not a break instruction */
532 return 0;
533 }
534
535 /* Is a break instruction */
536 return 1;
537}
538
539/*
540 * In this function, we check whether the target bundle modifies IP or
541 * it triggers an exception. If so, it cannot be boostable.
542 */
543static int __kprobes can_boost(bundle_t *bundle, uint slot,
544 unsigned long bundle_addr)
545{
546 unsigned int template = bundle->quad0.template;
547
548 do {
549 if (search_exception_tables(bundle_addr + slot) ||
550 __is_ia64_break_inst(bundle, slot))
551 return 0; /* exception may occur in this bundle*/
552 } while ((++slot) < 3);
553 template &= 0x1e;
554 if (template >= 0x10 /* including B unit */ ||
555 template == 0x04 /* including X unit */ ||
556 template == 0x06) /* undefined */
557 return 0;
558
559 return 1;
560}
561
562/* Prepare long jump bundle and disables other boosters if need */
563static void __kprobes prepare_booster(struct kprobe *p)
564{
565 unsigned long addr = (unsigned long)p->addr & ~0xFULL;
566 unsigned int slot = (unsigned long)p->addr & 0xf;
567 struct kprobe *other_kp;
568
569 if (can_boost(&p->ainsn.insn[0].bundle, slot, addr)) {
570 set_brl_inst(&p->ainsn.insn[1].bundle, (bundle_t *)addr + 1);
571 p->ainsn.inst_flag |= INST_FLAG_BOOSTABLE;
572 }
573
574 /* disables boosters in previous slots */
575 for (; addr < (unsigned long)p->addr; addr++) {
576 other_kp = get_kprobe((void *)addr);
577 if (other_kp)
578 other_kp->ainsn.inst_flag &= ~INST_FLAG_BOOSTABLE;
579 }
580}
581
582int __kprobes arch_prepare_kprobe(struct kprobe *p)
583{
584 unsigned long addr = (unsigned long) p->addr;
585 unsigned long *kprobe_addr = (unsigned long *)(addr & ~0xFULL);
586 unsigned long kprobe_inst=0;
587 unsigned int slot = addr & 0xf, template, major_opcode = 0;
588 bundle_t *bundle;
589 int qp;
590
591 bundle = &((kprobe_opcode_t *)kprobe_addr)->bundle;
592 template = bundle->quad0.template;
593
594 if(valid_kprobe_addr(template, slot, addr))
595 return -EINVAL;
596
597 /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
598 if (slot == 1 && bundle_encoding[template][1] == L)
599 slot++;
600
601 /* Get kprobe_inst and major_opcode from the bundle */
602 get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
603
604 qp = unsupported_inst(template, slot, major_opcode, kprobe_inst, addr);
605 if (qp < 0)
606 return -EINVAL;
607
608 p->ainsn.insn = get_insn_slot();
609 if (!p->ainsn.insn)
610 return -ENOMEM;
611 memcpy(&p->opcode, kprobe_addr, sizeof(kprobe_opcode_t));
612 memcpy(p->ainsn.insn, kprobe_addr, sizeof(kprobe_opcode_t));
613
614 prepare_break_inst(template, slot, major_opcode, kprobe_inst, p, qp);
615
616 prepare_booster(p);
617
618 return 0;
619}
620
621void __kprobes arch_arm_kprobe(struct kprobe *p)
622{
623 unsigned long arm_addr;
624 bundle_t *src, *dest;
625
626 arm_addr = ((unsigned long)p->addr) & ~0xFUL;
627 dest = &((kprobe_opcode_t *)arm_addr)->bundle;
628 src = &p->opcode.bundle;
629
630 flush_icache_range((unsigned long)p->ainsn.insn,
631 (unsigned long)p->ainsn.insn +
632 sizeof(kprobe_opcode_t) * MAX_INSN_SIZE);
633
634 switch (p->ainsn.slot) {
635 case 0:
636 dest->quad0.slot0 = src->quad0.slot0;
637 break;
638 case 1:
639 dest->quad1.slot1_p1 = src->quad1.slot1_p1;
640 break;
641 case 2:
642 dest->quad1.slot2 = src->quad1.slot2;
643 break;
644 }
645 flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
646}
647
648void __kprobes arch_disarm_kprobe(struct kprobe *p)
649{
650 unsigned long arm_addr;
651 bundle_t *src, *dest;
652
653 arm_addr = ((unsigned long)p->addr) & ~0xFUL;
654 dest = &((kprobe_opcode_t *)arm_addr)->bundle;
655 /* p->ainsn.insn contains the original unaltered kprobe_opcode_t */
656 src = &p->ainsn.insn->bundle;
657 switch (p->ainsn.slot) {
658 case 0:
659 dest->quad0.slot0 = src->quad0.slot0;
660 break;
661 case 1:
662 dest->quad1.slot1_p1 = src->quad1.slot1_p1;
663 break;
664 case 2:
665 dest->quad1.slot2 = src->quad1.slot2;
666 break;
667 }
668 flush_icache_range(arm_addr, arm_addr + sizeof(kprobe_opcode_t));
669}
670
671void __kprobes arch_remove_kprobe(struct kprobe *p)
672{
673 if (p->ainsn.insn) {
674 free_insn_slot(p->ainsn.insn,
675 p->ainsn.inst_flag & INST_FLAG_BOOSTABLE);
676 p->ainsn.insn = NULL;
677 }
678}
679/*
680 * We are resuming execution after a single step fault, so the pt_regs
681 * structure reflects the register state after we executed the instruction
682 * located in the kprobe (p->ainsn.insn->bundle). We still need to adjust
683 * the ip to point back to the original stack address. To set the IP address
684 * to original stack address, handle the case where we need to fixup the
685 * relative IP address and/or fixup branch register.
686 */
687static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
688{
689 unsigned long bundle_addr = (unsigned long) (&p->ainsn.insn->bundle);
690 unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL;
691 unsigned long template;
692 int slot = ((unsigned long)p->addr & 0xf);
693
694 template = p->ainsn.insn->bundle.quad0.template;
695
696 if (slot == 1 && bundle_encoding[template][1] == L)
697 slot = 2;
698
699 if (p->ainsn.inst_flag & ~INST_FLAG_BOOSTABLE) {
700
701 if (p->ainsn.inst_flag & INST_FLAG_FIX_RELATIVE_IP_ADDR) {
702 /* Fix relative IP address */
703 regs->cr_iip = (regs->cr_iip - bundle_addr) +
704 resume_addr;
705 }
706
707 if (p->ainsn.inst_flag & INST_FLAG_FIX_BRANCH_REG) {
708 /*
709 * Fix target branch register, software convention is
710 * to use either b0 or b6 or b7, so just checking
711 * only those registers
712 */
713 switch (p->ainsn.target_br_reg) {
714 case 0:
715 if ((regs->b0 == bundle_addr) ||
716 (regs->b0 == bundle_addr + 0x10)) {
717 regs->b0 = (regs->b0 - bundle_addr) +
718 resume_addr;
719 }
720 break;
721 case 6:
722 if ((regs->b6 == bundle_addr) ||
723 (regs->b6 == bundle_addr + 0x10)) {
724 regs->b6 = (regs->b6 - bundle_addr) +
725 resume_addr;
726 }
727 break;
728 case 7:
729 if ((regs->b7 == bundle_addr) ||
730 (regs->b7 == bundle_addr + 0x10)) {
731 regs->b7 = (regs->b7 - bundle_addr) +
732 resume_addr;
733 }
734 break;
735 } /* end switch */
736 }
737 goto turn_ss_off;
738 }
739
740 if (slot == 2) {
741 if (regs->cr_iip == bundle_addr + 0x10) {
742 regs->cr_iip = resume_addr + 0x10;
743 }
744 } else {
745 if (regs->cr_iip == bundle_addr) {
746 regs->cr_iip = resume_addr;
747 }
748 }
749
750turn_ss_off:
751 /* Turn off Single Step bit */
752 ia64_psr(regs)->ss = 0;
753}
754
755static void __kprobes prepare_ss(struct kprobe *p, struct pt_regs *regs)
756{
757 unsigned long bundle_addr = (unsigned long) &p->ainsn.insn->bundle;
758 unsigned long slot = (unsigned long)p->addr & 0xf;
759
760 /* single step inline if break instruction */
761 if (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)
762 regs->cr_iip = (unsigned long)p->addr & ~0xFULL;
763 else
764 regs->cr_iip = bundle_addr & ~0xFULL;
765
766 if (slot > 2)
767 slot = 0;
768
769 ia64_psr(regs)->ri = slot;
770
771 /* turn on single stepping */
772 ia64_psr(regs)->ss = 1;
773}
774
775static int __kprobes is_ia64_break_inst(struct pt_regs *regs)
776{
777 unsigned int slot = ia64_psr(regs)->ri;
778 unsigned long *kprobe_addr = (unsigned long *)regs->cr_iip;
779 bundle_t bundle;
780
781 memcpy(&bundle, kprobe_addr, sizeof(bundle_t));
782
783 return __is_ia64_break_inst(&bundle, slot);
784}
785
786static int __kprobes pre_kprobes_handler(struct die_args *args)
787{
788 struct kprobe *p;
789 int ret = 0;
790 struct pt_regs *regs = args->regs;
791 kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);
792 struct kprobe_ctlblk *kcb;
793
794 /*
795 * We don't want to be preempted for the entire
796 * duration of kprobe processing
797 */
798 preempt_disable();
799 kcb = get_kprobe_ctlblk();
800
801 /* Handle recursion cases */
802 if (kprobe_running()) {
803 p = get_kprobe(addr);
804 if (p) {
805 if ((kcb->kprobe_status == KPROBE_HIT_SS) &&
806 (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)) {
807 ia64_psr(regs)->ss = 0;
808 goto no_kprobe;
809 }
810 /* We have reentered the pre_kprobe_handler(), since
811 * another probe was hit while within the handler.
812 * We here save the original kprobes variables and
813 * just single step on the instruction of the new probe
814 * without calling any user handlers.
815 */
816 save_previous_kprobe(kcb);
817 set_current_kprobe(p, kcb);
818 kprobes_inc_nmissed_count(p);
819 prepare_ss(p, regs);
820 kcb->kprobe_status = KPROBE_REENTER;
821 return 1;
822 } else if (args->err == __IA64_BREAK_JPROBE) {
823 /*
824 * jprobe instrumented function just completed
825 */
826 p = __get_cpu_var(current_kprobe);
827 if (p->break_handler && p->break_handler(p, regs)) {
828 goto ss_probe;
829 }
830 } else if (!is_ia64_break_inst(regs)) {
831 /* The breakpoint instruction was removed by
832 * another cpu right after we hit, no further
833 * handling of this interrupt is appropriate
834 */
835 ret = 1;
836 goto no_kprobe;
837 } else {
838 /* Not our break */
839 goto no_kprobe;
840 }
841 }
842
843 p = get_kprobe(addr);
844 if (!p) {
845 if (!is_ia64_break_inst(regs)) {
846 /*
847 * The breakpoint instruction was removed right
848 * after we hit it. Another cpu has removed
849 * either a probepoint or a debugger breakpoint
850 * at this address. In either case, no further
851 * handling of this interrupt is appropriate.
852 */
853 ret = 1;
854
855 }
856
857 /* Not one of our break, let kernel handle it */
858 goto no_kprobe;
859 }
860
861 set_current_kprobe(p, kcb);
862 kcb->kprobe_status = KPROBE_HIT_ACTIVE;
863
864 if (p->pre_handler && p->pre_handler(p, regs))
865 /*
866 * Our pre-handler is specifically requesting that we just
867 * do a return. This is used for both the jprobe pre-handler
868 * and the kretprobe trampoline
869 */
870 return 1;
871
872ss_probe:
873#if !defined(CONFIG_PREEMPT)
874 if (p->ainsn.inst_flag == INST_FLAG_BOOSTABLE && !p->post_handler) {
875 /* Boost up -- we can execute copied instructions directly */
876 ia64_psr(regs)->ri = p->ainsn.slot;
877 regs->cr_iip = (unsigned long)&p->ainsn.insn->bundle & ~0xFULL;
878 /* turn single stepping off */
879 ia64_psr(regs)->ss = 0;
880
881 reset_current_kprobe();
882 preempt_enable_no_resched();
883 return 1;
884 }
885#endif
886 prepare_ss(p, regs);
887 kcb->kprobe_status = KPROBE_HIT_SS;
888 return 1;
889
890no_kprobe:
891 preempt_enable_no_resched();
892 return ret;
893}
894
895static int __kprobes post_kprobes_handler(struct pt_regs *regs)
896{
897 struct kprobe *cur = kprobe_running();
898 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
899
900 if (!cur)
901 return 0;
902
903 if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
904 kcb->kprobe_status = KPROBE_HIT_SSDONE;
905 cur->post_handler(cur, regs, 0);
906 }
907
908 resume_execution(cur, regs);
909
910 /*Restore back the original saved kprobes variables and continue. */
911 if (kcb->kprobe_status == KPROBE_REENTER) {
912 restore_previous_kprobe(kcb);
913 goto out;
914 }
915 reset_current_kprobe();
916
917out:
918 preempt_enable_no_resched();
919 return 1;
920}
921
922int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
923{
924 struct kprobe *cur = kprobe_running();
925 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
926
927
928 switch(kcb->kprobe_status) {
929 case KPROBE_HIT_SS:
930 case KPROBE_REENTER:
931 /*
932 * We are here because the instruction being single
933 * stepped caused a page fault. We reset the current
934 * kprobe and the instruction pointer points back to
935 * the probe address and allow the page fault handler
936 * to continue as a normal page fault.
937 */
938 regs->cr_iip = ((unsigned long)cur->addr) & ~0xFULL;
939 ia64_psr(regs)->ri = ((unsigned long)cur->addr) & 0xf;
940 if (kcb->kprobe_status == KPROBE_REENTER)
941 restore_previous_kprobe(kcb);
942 else
943 reset_current_kprobe();
944 preempt_enable_no_resched();
945 break;
946 case KPROBE_HIT_ACTIVE:
947 case KPROBE_HIT_SSDONE:
948 /*
949 * We increment the nmissed count for accounting,
950 * we can also use npre/npostfault count for accouting
951 * these specific fault cases.
952 */
953 kprobes_inc_nmissed_count(cur);
954
955 /*
956 * We come here because instructions in the pre/post
957 * handler caused the page_fault, this could happen
958 * if handler tries to access user space by
959 * copy_from_user(), get_user() etc. Let the
960 * user-specified handler try to fix it first.
961 */
962 if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
963 return 1;
964 /*
965 * In case the user-specified fault handler returned
966 * zero, try to fix up.
967 */
968 if (ia64_done_with_exception(regs))
969 return 1;
970
971 /*
972 * Let ia64_do_page_fault() fix it.
973 */
974 break;
975 default:
976 break;
977 }
978
979 return 0;
980}
981
982int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
983 unsigned long val, void *data)
984{
985 struct die_args *args = (struct die_args *)data;
986 int ret = NOTIFY_DONE;
987
988 if (args->regs && user_mode(args->regs))
989 return ret;
990
991 switch(val) {
992 case DIE_BREAK:
993 /* err is break number from ia64_bad_break() */
994 if ((args->err >> 12) == (__IA64_BREAK_KPROBE >> 12)
995 || args->err == __IA64_BREAK_JPROBE
996 || args->err == 0)
997 if (pre_kprobes_handler(args))
998 ret = NOTIFY_STOP;
999 break;
1000 case DIE_FAULT:
1001 /* err is vector number from ia64_fault() */
1002 if (args->err == 36)
1003 if (post_kprobes_handler(args->regs))
1004 ret = NOTIFY_STOP;
1005 break;
1006 default:
1007 break;
1008 }
1009 return ret;
1010}
1011
1012struct param_bsp_cfm {
1013 unsigned long ip;
1014 unsigned long *bsp;
1015 unsigned long cfm;
1016};
1017
1018static void ia64_get_bsp_cfm(struct unw_frame_info *info, void *arg)
1019{
1020 unsigned long ip;
1021 struct param_bsp_cfm *lp = arg;
1022
1023 do {
1024 unw_get_ip(info, &ip);
1025 if (ip == 0)
1026 break;
1027 if (ip == lp->ip) {
1028 unw_get_bsp(info, (unsigned long*)&lp->bsp);
1029 unw_get_cfm(info, (unsigned long*)&lp->cfm);
1030 return;
1031 }
1032 } while (unw_unwind(info) >= 0);
1033 lp->bsp = NULL;
1034 lp->cfm = 0;
1035 return;
1036}
1037
1038unsigned long arch_deref_entry_point(void *entry)
1039{
1040 return ((struct fnptr *)entry)->ip;
1041}
1042
1043int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
1044{
1045 struct jprobe *jp = container_of(p, struct jprobe, kp);
1046 unsigned long addr = arch_deref_entry_point(jp->entry);
1047 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
1048 struct param_bsp_cfm pa;
1049 int bytes;
1050
1051 /*
1052 * Callee owns the argument space and could overwrite it, eg
1053 * tail call optimization. So to be absolutely safe
1054 * we save the argument space before transferring the control
1055 * to instrumented jprobe function which runs in
1056 * the process context
1057 */
1058 pa.ip = regs->cr_iip;
1059 unw_init_running(ia64_get_bsp_cfm, &pa);
1060 bytes = (char *)ia64_rse_skip_regs(pa.bsp, pa.cfm & 0x3f)
1061 - (char *)pa.bsp;
1062 memcpy( kcb->jprobes_saved_stacked_regs,
1063 pa.bsp,
1064 bytes );
1065 kcb->bsp = pa.bsp;
1066 kcb->cfm = pa.cfm;
1067
1068 /* save architectural state */
1069 kcb->jprobe_saved_regs = *regs;
1070
1071 /* after rfi, execute the jprobe instrumented function */
1072 regs->cr_iip = addr & ~0xFULL;
1073 ia64_psr(regs)->ri = addr & 0xf;
1074 regs->r1 = ((struct fnptr *)(jp->entry))->gp;
1075
1076 /*
1077 * fix the return address to our jprobe_inst_return() function
1078 * in the jprobes.S file
1079 */
1080 regs->b0 = ((struct fnptr *)(jprobe_inst_return))->ip;
1081
1082 return 1;
1083}
1084
1085/* ia64 does not need this */
1086void __kprobes jprobe_return(void)
1087{
1088}
1089
1090int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
1091{
1092 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
1093 int bytes;
1094
1095 /* restoring architectural state */
1096 *regs = kcb->jprobe_saved_regs;
1097
1098 /* restoring the original argument space */
1099 flush_register_stack();
1100 bytes = (char *)ia64_rse_skip_regs(kcb->bsp, kcb->cfm & 0x3f)
1101 - (char *)kcb->bsp;
1102 memcpy( kcb->bsp,
1103 kcb->jprobes_saved_stacked_regs,
1104 bytes );
1105 invalidate_stacked_regs();
1106
1107 preempt_enable_no_resched();
1108 return 1;
1109}
1110
1111static struct kprobe trampoline_p = {
1112 .pre_handler = trampoline_probe_handler
1113};
1114
1115int __init arch_init_kprobes(void)
1116{
1117 trampoline_p.addr =
1118 (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip;
1119 return register_kprobe(&trampoline_p);
1120}
1121
1122int __kprobes arch_trampoline_kprobe(struct kprobe *p)
1123{
1124 if (p->addr ==
1125 (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip)
1126 return 1;
1127
1128 return 0;
1129}