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[PATCH] kprobes: fix handling of simultaneous probe hit/unregister
[deliverable/linux.git] / arch / ia64 / kernel / kprobes.c
CommitLineData
fd7b231f
AK		 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/config.h>
27#include <linux/kprobes.h>
28#include <linux/ptrace.h>
29#include <linux/spinlock.h>
30#include <linux/string.h>
31#include <linux/slab.h>
32#include <linux/preempt.h>
33#include <linux/moduleloader.h>
34
35#include <asm/pgtable.h>
36#include <asm/kdebug.h>
c7b645f9 37#include <asm/sections.h>
fd7b231f 38
b2761dc2
AK		 39extern void jprobe_inst_return(void);
40
fd7b231f
AK		 41/* kprobe_status settings */
42#define KPROBE_HIT_ACTIVE 0x00000001
43#define KPROBE_HIT_SS 0x00000002
44
852caccc
AK		 45static struct kprobe *current_kprobe, *kprobe_prev;
46static unsigned long kprobe_status, kprobe_status_prev;
b2761dc2 47static struct pt_regs jprobe_saved_regs;
fd7b231f
AK		 48
49enum instruction_type {A, I, M, F, B, L, X, u};
50static enum instruction_type bundle_encoding[32][3] = {
51 { M, I, I }, /* 00 */
52 { M, I, I }, /* 01 */
53 { M, I, I }, /* 02 */
54 { M, I, I }, /* 03 */
55 { M, L, X }, /* 04 */
56 { M, L, X }, /* 05 */
57 { u, u, u }, /* 06 */
58 { u, u, u }, /* 07 */
59 { M, M, I }, /* 08 */
60 { M, M, I }, /* 09 */
61 { M, M, I }, /* 0A */
62 { M, M, I }, /* 0B */
63 { M, F, I }, /* 0C */
64 { M, F, I }, /* 0D */
65 { M, M, F }, /* 0E */
66 { M, M, F }, /* 0F */
67 { M, I, B }, /* 10 */
68 { M, I, B }, /* 11 */
69 { M, B, B }, /* 12 */
70 { M, B, B }, /* 13 */
71 { u, u, u }, /* 14 */
72 { u, u, u }, /* 15 */
73 { B, B, B }, /* 16 */
74 { B, B, B }, /* 17 */
75 { M, M, B }, /* 18 */
76 { M, M, B }, /* 19 */
77 { u, u, u }, /* 1A */
78 { u, u, u }, /* 1B */
79 { M, F, B }, /* 1C */
80 { M, F, B }, /* 1D */
81 { u, u, u }, /* 1E */
82 { u, u, u }, /* 1F */
83};
84
a5403183
AK		 85/*
86 * In this function we check to see if the instruction
87 * is IP relative instruction and update the kprobe
88 * inst flag accordingly
89 */
1f7ad57b
PP		 90static void __kprobes update_kprobe_inst_flag(uint template, uint slot,
91 uint major_opcode,
92 unsigned long kprobe_inst,
93 struct kprobe *p)
fd7b231f 94{
8bc76772
RL		 95 p->ainsn.inst_flag = 0;
96 p->ainsn.target_br_reg = 0;
fd7b231f 97
a5403183
AK		 98 if (bundle_encoding[template][slot] == B) {
99 switch (major_opcode) {
100 case INDIRECT_CALL_OPCODE:
101 p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
102 p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
103 break;
104 case IP_RELATIVE_PREDICT_OPCODE:
105 case IP_RELATIVE_BRANCH_OPCODE:
106 p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
107 break;
108 case IP_RELATIVE_CALL_OPCODE:
109 p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
110 p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
111 p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
112 break;
113 }
114 } else if (bundle_encoding[template][slot] == X) {
115 switch (major_opcode) {
116 case LONG_CALL_OPCODE:
117 p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
118 p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
119 break;
120 }
121 }
122 return;
123}
fd7b231f 124
708de8f1
AK		 125/*
126 * In this function we check to see if the instruction
127 * on which we are inserting kprobe is supported.
128 * Returns 0 if supported
129 * Returns -EINVAL if unsupported
130 */
1f7ad57b
PP		 131static int __kprobes unsupported_inst(uint template, uint slot,
132 uint major_opcode,
133 unsigned long kprobe_inst,
134 struct kprobe *p)
708de8f1
AK		 135{
136 unsigned long addr = (unsigned long)p->addr;
137
138 if (bundle_encoding[template][slot] == I) {
139 switch (major_opcode) {
140 case 0x0: //I_UNIT_MISC_OPCODE:
141 /*
142 * Check for Integer speculation instruction
143 * - Bit 33-35 to be equal to 0x1
144 */
145 if (((kprobe_inst >> 33) & 0x7) == 1) {
146 printk(KERN_WARNING
147 "Kprobes on speculation inst at <0x%lx> not supported\n",
148 addr);
149 return -EINVAL;
150 }
151
152 /*
153 * IP relative mov instruction
154 * - Bit 27-35 to be equal to 0x30
155 */
156 if (((kprobe_inst >> 27) & 0x1FF) == 0x30) {
157 printk(KERN_WARNING
158 "Kprobes on \"mov r1=ip\" at <0x%lx> not supported\n",
159 addr);
160 return -EINVAL;
161
162 }
163 }
164 }
165 return 0;
166}
167
168
1674eafc
AK		 169/*
170 * In this function we check to see if the instruction
171 * (qp) cmpx.crel.ctype p1,p2=r2,r3
172 * on which we are inserting kprobe is cmp instruction
173 * with ctype as unc.
174 */
1f7ad57b
PP		 175static uint __kprobes is_cmp_ctype_unc_inst(uint template, uint slot,
176 uint major_opcode,
177 unsigned long kprobe_inst)
1674eafc
AK		 178{
179 cmp_inst_t cmp_inst;
180 uint ctype_unc = 0;
181
182 if (!((bundle_encoding[template][slot] == I) ||
183 (bundle_encoding[template][slot] == M)))
184 goto out;
185
186 if (!((major_opcode == 0xC) || (major_opcode == 0xD) ||
187 (major_opcode == 0xE)))
188 goto out;
189
190 cmp_inst.l = kprobe_inst;
191 if ((cmp_inst.f.x2 == 0) || (cmp_inst.f.x2 == 1)) {
192 /* Integere compare - Register Register (A6 type)*/
193 if ((cmp_inst.f.tb == 0) && (cmp_inst.f.ta == 0)
194 &&(cmp_inst.f.c == 1))
195 ctype_unc = 1;
196 } else if ((cmp_inst.f.x2 == 2)||(cmp_inst.f.x2 == 3)) {
197 /* Integere compare - Immediate Register (A8 type)*/
198 if ((cmp_inst.f.ta == 0) &&(cmp_inst.f.c == 1))
199 ctype_unc = 1;
200 }
201out:
202 return ctype_unc;
203}
204
a5403183
AK		 205/*
206 * In this function we override the bundle with
207 * the break instruction at the given slot.
208 */
1f7ad57b
PP		 209static void __kprobes prepare_break_inst(uint template, uint slot,
210 uint major_opcode,
211 unsigned long kprobe_inst,
212 struct kprobe *p)
a5403183
AK		 213{
214 unsigned long break_inst = BREAK_INST;
215 bundle_t *bundle = &p->ainsn.insn.bundle;
216
217 /*
218 * Copy the original kprobe_inst qualifying predicate(qp)
1674eafc
AK		 219 * to the break instruction iff !is_cmp_ctype_unc_inst
220 * because for cmp instruction with ctype equal to unc,
221 * which is a special instruction always needs to be
222 * executed regradless of qp
a5403183 223 */
1674eafc
AK		 224 if (!is_cmp_ctype_unc_inst(template, slot, major_opcode, kprobe_inst))
225 break_inst |= (0x3f & kprobe_inst);
a5403183
AK		 226
227 switch (slot) {
228 case 0:
229 bundle->quad0.slot0 = break_inst;
230 break;
231 case 1:
232 bundle->quad0.slot1_p0 = break_inst;
233 bundle->quad1.slot1_p1 = break_inst >> (64-46);
234 break;
235 case 2:
236 bundle->quad1.slot2 = break_inst;
237 break;
8bc76772 238 }
cd2675bf 239
a5403183
AK		 240 /*
241 * Update the instruction flag, so that we can
242 * emulate the instruction properly after we
243 * single step on original instruction
244 */
245 update_kprobe_inst_flag(template, slot, major_opcode, kprobe_inst, p);
246}
247
248static inline void get_kprobe_inst(bundle_t *bundle, uint slot,
249 unsigned long *kprobe_inst, uint *major_opcode)
250{
251 unsigned long kprobe_inst_p0, kprobe_inst_p1;
252 unsigned int template;
253
254 template = bundle->quad0.template;
fd7b231f 255
fd7b231f 256 switch (slot) {
a5403183
AK		 257 case 0:
258 *major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT);
259 *kprobe_inst = bundle->quad0.slot0;
fd7b231f 260 break;
a5403183
AK		 261 case 1:
262 *major_opcode = (bundle->quad1.slot1_p1 >> SLOT1_p1_OPCODE_SHIFT);
263 kprobe_inst_p0 = bundle->quad0.slot1_p0;
264 kprobe_inst_p1 = bundle->quad1.slot1_p1;
265 *kprobe_inst = kprobe_inst_p0 | (kprobe_inst_p1 << (64-46));
fd7b231f 266 break;
a5403183
AK		 267 case 2:
268 *major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT);
269 *kprobe_inst = bundle->quad1.slot2;
fd7b231f
AK		 270 break;
271 }
a5403183 272}
fd7b231f 273
c7b645f9
KA		 274/* Returns non-zero if the addr is in the Interrupt Vector Table */
275static inline int in_ivt_functions(unsigned long addr)
276{
277 return (addr >= (unsigned long)__start_ivt_text
278 && addr < (unsigned long)__end_ivt_text);
279}
280
1f7ad57b
PP		 281static int __kprobes valid_kprobe_addr(int template, int slot,
282 unsigned long addr)
a5403183
AK		 283{
284 if ((slot > 2) || ((bundle_encoding[template][1] == L) && slot > 1)) {
c7b645f9
KA		 285 printk(KERN_WARNING "Attempting to insert unaligned kprobe "
286 "at 0x%lx\n", addr);
a5403183 287 return -EINVAL;
8bc76772 288 }
a528e21c 289
c7b645f9
KA		 290 if (in_ivt_functions(addr)) {
291 printk(KERN_WARNING "Kprobes can't be inserted inside "
292 "IVT functions at 0x%lx\n", addr);
293 return -EINVAL;
294 }
295
a528e21c
RL		 296 if (slot == 1 && bundle_encoding[template][1] != L) {
297 printk(KERN_WARNING "Inserting kprobes on slot #1 "
298 "is not supported\n");
299 return -EINVAL;
300 }
301
a5403183
AK		 302 return 0;
303}
304
852caccc
AK		 305static inline void save_previous_kprobe(void)
306{
307 kprobe_prev = current_kprobe;
308 kprobe_status_prev = kprobe_status;
309}
310
311static inline void restore_previous_kprobe(void)
312{
313 current_kprobe = kprobe_prev;
314 kprobe_status = kprobe_status_prev;
315}
316
317static inline void set_current_kprobe(struct kprobe *p)
318{
319 current_kprobe = p;
320}
321
9508dbfe
RL		 322static void kretprobe_trampoline(void)
323{
324}
325
326/*
327 * At this point the target function has been tricked into
328 * returning into our trampoline. Lookup the associated instance
329 * and then:
330 * - call the handler function
331 * - cleanup by marking the instance as unused
332 * - long jump back to the original return address
333 */
1f7ad57b 334int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
9508dbfe
RL		 335{
336 struct kretprobe_instance *ri = NULL;
337 struct hlist_head *head;
338 struct hlist_node *node, *tmp;
339 unsigned long orig_ret_address = 0;
340 unsigned long trampoline_address =
341 ((struct fnptr *)kretprobe_trampoline)->ip;
342
343 head = kretprobe_inst_table_head(current);
344
345 /*
346 * It is possible to have multiple instances associated with a given
347 * task either because an multiple functions in the call path
348 * have a return probe installed on them, and/or more then one return
349 * return probe was registered for a target function.
350 *
351 * We can handle this because:
352 * - instances are always inserted at the head of the list
353 * - when multiple return probes are registered for the same
354 * function, the first instance's ret_addr will point to the
355 * real return address, and all the rest will point to
356 * kretprobe_trampoline
357 */
358 hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
359 if (ri->task != current)
360 /* another task is sharing our hash bucket */
361 continue;
362
363 if (ri->rp && ri->rp->handler)
364 ri->rp->handler(ri, regs);
365
366 orig_ret_address = (unsigned long)ri->ret_addr;
367 recycle_rp_inst(ri);
368
369 if (orig_ret_address != trampoline_address)
370 /*
371 * This is the real return address. Any other
372 * instances associated with this task are for
373 * other calls deeper on the call stack
374 */
375 break;
376 }
377
378 BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address));
379 regs->cr_iip = orig_ret_address;
380
381 unlock_kprobes();
382 preempt_enable_no_resched();
383
384 /*
385 * By returning a non-zero value, we are telling
386 * kprobe_handler() that we have handled unlocking
387 * and re-enabling preemption.
388 */
389 return 1;
390}
391
1f7ad57b
PP		 392void __kprobes arch_prepare_kretprobe(struct kretprobe *rp,
393 struct pt_regs *regs)
9508dbfe
RL		 394{
395 struct kretprobe_instance *ri;
396
397 if ((ri = get_free_rp_inst(rp)) != NULL) {
398 ri->rp = rp;
399 ri->task = current;
400 ri->ret_addr = (kprobe_opcode_t *)regs->b0;
401
402 /* Replace the return addr with trampoline addr */
403 regs->b0 = ((struct fnptr *)kretprobe_trampoline)->ip;
404
405 add_rp_inst(ri);
406 } else {
407 rp->nmissed++;
408 }
409}
410
1f7ad57b 411int __kprobes arch_prepare_kprobe(struct kprobe *p)
a5403183
AK		 412{
413 unsigned long addr = (unsigned long) p->addr;
414 unsigned long *kprobe_addr = (unsigned long *)(addr & ~0xFULL);
415 unsigned long kprobe_inst=0;
416 unsigned int slot = addr & 0xf, template, major_opcode = 0;
417 bundle_t *bundle = &p->ainsn.insn.bundle;
418
419 memcpy(&p->opcode.bundle, kprobe_addr, sizeof(bundle_t));
420 memcpy(&p->ainsn.insn.bundle, kprobe_addr, sizeof(bundle_t));
421
422 template = bundle->quad0.template;
423
424 if(valid_kprobe_addr(template, slot, addr))
425 return -EINVAL;
426
427 /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
428 if (slot == 1 && bundle_encoding[template][1] == L)
429 slot++;
430
431 /* Get kprobe_inst and major_opcode from the bundle */
432 get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
433
708de8f1
AK		 434 if (unsupported_inst(template, slot, major_opcode, kprobe_inst, p))
435 return -EINVAL;
436
a5403183 437 prepare_break_inst(template, slot, major_opcode, kprobe_inst, p);
8bc76772
RL		 438
439 return 0;
440}
441
1f7ad57b 442void __kprobes arch_arm_kprobe(struct kprobe *p)
8bc76772
RL		 443{
444 unsigned long addr = (unsigned long)p->addr;
445 unsigned long arm_addr = addr & ~0xFULL;
446
447 memcpy((char *)arm_addr, &p->ainsn.insn.bundle, sizeof(bundle_t));
fd7b231f
AK		 448 flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t));
449}
450
1f7ad57b 451void __kprobes arch_disarm_kprobe(struct kprobe *p)
fd7b231f
AK		 452{
453 unsigned long addr = (unsigned long)p->addr;
454 unsigned long arm_addr = addr & ~0xFULL;
455
456 /* p->opcode contains the original unaltered bundle */
457 memcpy((char *) arm_addr, (char *) &p->opcode.bundle, sizeof(bundle_t));
458 flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t));
459}
460
1f7ad57b 461void __kprobes arch_remove_kprobe(struct kprobe *p)
fd7b231f
AK		 462{
463}
464
465/*
466 * We are resuming execution after a single step fault, so the pt_regs
467 * structure reflects the register state after we executed the instruction
468 * located in the kprobe (p->ainsn.insn.bundle). We still need to adjust
cd2675bf
AK		 469 * the ip to point back to the original stack address. To set the IP address
470 * to original stack address, handle the case where we need to fixup the
471 * relative IP address and/or fixup branch register.
fd7b231f 472 */
1f7ad57b 473static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
fd7b231f 474{
8bc76772 475 unsigned long bundle_addr = ((unsigned long) (&p->opcode.bundle)) & ~0xFULL;
cd2675bf
AK		 476 unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL;
477 unsigned long template;
478 int slot = ((unsigned long)p->addr & 0xf);
fd7b231f 479
cd2675bf
AK		 480 template = p->opcode.bundle.quad0.template;
481
482 if (slot == 1 && bundle_encoding[template][1] == L)
483 slot = 2;
484
485 if (p->ainsn.inst_flag) {
486
487 if (p->ainsn.inst_flag & INST_FLAG_FIX_RELATIVE_IP_ADDR) {
488 /* Fix relative IP address */
489 regs->cr_iip = (regs->cr_iip - bundle_addr) + resume_addr;
490 }
491
492 if (p->ainsn.inst_flag & INST_FLAG_FIX_BRANCH_REG) {
493 /*
494 * Fix target branch register, software convention is
495 * to use either b0 or b6 or b7, so just checking
496 * only those registers
497 */
498 switch (p->ainsn.target_br_reg) {
499 case 0:
500 if ((regs->b0 == bundle_addr) ||
501 (regs->b0 == bundle_addr + 0x10)) {
502 regs->b0 = (regs->b0 - bundle_addr) +
503 resume_addr;
504 }
505 break;
506 case 6:
507 if ((regs->b6 == bundle_addr) ||
508 (regs->b6 == bundle_addr + 0x10)) {
509 regs->b6 = (regs->b6 - bundle_addr) +
510 resume_addr;
511 }
512 break;
513 case 7:
514 if ((regs->b7 == bundle_addr) ||
515 (regs->b7 == bundle_addr + 0x10)) {
516 regs->b7 = (regs->b7 - bundle_addr) +
517 resume_addr;
518 }
519 break;
520 } /* end switch */
521 }
522 goto turn_ss_off;
523 }
fd7b231f 524
cd2675bf
AK		 525 if (slot == 2) {
526 if (regs->cr_iip == bundle_addr + 0x10) {
527 regs->cr_iip = resume_addr + 0x10;
528 }
529 } else {
530 if (regs->cr_iip == bundle_addr) {
531 regs->cr_iip = resume_addr;
532 }
a5403183 533 }
fd7b231f 534
cd2675bf
AK		 535turn_ss_off:
536 /* Turn off Single Step bit */
537 ia64_psr(regs)->ss = 0;
fd7b231f
AK		 538}
539
1f7ad57b 540static void __kprobes prepare_ss(struct kprobe *p, struct pt_regs *regs)
fd7b231f 541{
8bc76772 542 unsigned long bundle_addr = (unsigned long) &p->opcode.bundle;
fd7b231f
AK		 543 unsigned long slot = (unsigned long)p->addr & 0xf;
544
545 /* Update instruction pointer (IIP) and slot number (IPSR.ri) */
546 regs->cr_iip = bundle_addr & ~0xFULL;
547
548 if (slot > 2)
549 slot = 0;
550
551 ia64_psr(regs)->ri = slot;
552
553 /* turn on single stepping */
554 ia64_psr(regs)->ss = 1;
555}
556
661e5a3d
KA		 557static int __kprobes is_ia64_break_inst(struct pt_regs *regs)
558{
559 unsigned int slot = ia64_psr(regs)->ri;
560 unsigned int template, major_opcode;
561 unsigned long kprobe_inst;
562 unsigned long *kprobe_addr = (unsigned long *)regs->cr_iip;
563 bundle_t bundle;
564
565 memcpy(&bundle, kprobe_addr, sizeof(bundle_t));
566 template = bundle.quad0.template;
567
568 /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
569 if (slot == 1 && bundle_encoding[template][1] == L)
570 slot++;
571
572 /* Get Kprobe probe instruction at given slot*/
573 get_kprobe_inst(&bundle, slot, &kprobe_inst, &major_opcode);
574
575 /* For break instruction,
576 * Bits 37:40 Major opcode to be zero
577 * Bits 27:32 X6 to be zero
578 * Bits 32:35 X3 to be zero
579 */
580 if (major_opcode || ((kprobe_inst >> 27) & 0x1FF) ) {
581 /* Not a break instruction */
582 return 0;
583 }
584
585 /* Is a break instruction */
586 return 1;
587}
588
1f7ad57b 589static int __kprobes pre_kprobes_handler(struct die_args *args)
fd7b231f
AK		 590{
591 struct kprobe *p;
592 int ret = 0;
89cb14c0 593 struct pt_regs *regs = args->regs;
fd7b231f
AK		 594 kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);
595
596 preempt_disable();
597
598 /* Handle recursion cases */
599 if (kprobe_running()) {
600 p = get_kprobe(addr);
601 if (p) {
602 if (kprobe_status == KPROBE_HIT_SS) {
603 unlock_kprobes();
604 goto no_kprobe;
605 }
852caccc
AK		 606 /* We have reentered the pre_kprobe_handler(), since
607 * another probe was hit while within the handler.
608 * We here save the original kprobes variables and
609 * just single step on the instruction of the new probe
610 * without calling any user handlers.
611 */
612 save_previous_kprobe();
613 set_current_kprobe(p);
614 p->nmissed++;
615 prepare_ss(p, regs);
616 kprobe_status = KPROBE_REENTER;
617 return 1;
89cb14c0 618 } else if (args->err == __IA64_BREAK_JPROBE) {
fd7b231f
AK		 619 /*
620 * jprobe instrumented function just completed
621 */
622 p = current_kprobe;
623 if (p->break_handler && p->break_handler(p, regs)) {
624 goto ss_probe;
625 }
89cb14c0
KA		 626 } else {
627 /* Not our break */
628 goto no_kprobe;
fd7b231f
AK		 629 }
630 }
631
632 lock_kprobes();
633 p = get_kprobe(addr);
634 if (!p) {
635 unlock_kprobes();
661e5a3d
KA		 636 if (!is_ia64_break_inst(regs)) {
637 /*
638 * The breakpoint instruction was removed right
639 * after we hit it. Another cpu has removed
640 * either a probepoint or a debugger breakpoint
641 * at this address. In either case, no further
642 * handling of this interrupt is appropriate.
643 */
644 ret = 1;
645
646 }
647
648 /* Not one of our break, let kernel handle it */
fd7b231f
AK		 649 goto no_kprobe;
650 }
651
652 kprobe_status = KPROBE_HIT_ACTIVE;
852caccc 653 set_current_kprobe(p);
fd7b231f
AK		 654
655 if (p->pre_handler && p->pre_handler(p, regs))
656 /*
657 * Our pre-handler is specifically requesting that we just
9508dbfe
RL		 658 * do a return. This is used for both the jprobe pre-handler
659 * and the kretprobe trampoline
fd7b231f
AK		 660 */
661 return 1;
662
663ss_probe:
664 prepare_ss(p, regs);
665 kprobe_status = KPROBE_HIT_SS;
666 return 1;
667
668no_kprobe:
669 preempt_enable_no_resched();
670 return ret;
671}
672
1f7ad57b 673static int __kprobes post_kprobes_handler(struct pt_regs *regs)
fd7b231f
AK		 674{
675 if (!kprobe_running())
676 return 0;
677
852caccc
AK		 678 if ((kprobe_status != KPROBE_REENTER) && current_kprobe->post_handler) {
679 kprobe_status = KPROBE_HIT_SSDONE;
fd7b231f 680 current_kprobe->post_handler(current_kprobe, regs, 0);
852caccc 681 }
fd7b231f
AK		 682
683 resume_execution(current_kprobe, regs);
684
852caccc
AK		 685 /*Restore back the original saved kprobes variables and continue. */
686 if (kprobe_status == KPROBE_REENTER) {
687 restore_previous_kprobe();
688 goto out;
689 }
690
fd7b231f 691 unlock_kprobes();
852caccc
AK		 692
693out:
fd7b231f
AK		 694 preempt_enable_no_resched();
695 return 1;
696}
697
1f7ad57b 698static int __kprobes kprobes_fault_handler(struct pt_regs *regs, int trapnr)
fd7b231f
AK		 699{
700 if (!kprobe_running())
701 return 0;
702
703 if (current_kprobe->fault_handler &&
704 current_kprobe->fault_handler(current_kprobe, regs, trapnr))
705 return 1;
706
707 if (kprobe_status & KPROBE_HIT_SS) {
708 resume_execution(current_kprobe, regs);
709 unlock_kprobes();
710 preempt_enable_no_resched();
711 }
712
713 return 0;
714}
715
1f7ad57b
PP		 716int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
717 unsigned long val, void *data)
fd7b231f
AK		 718{
719 struct die_args *args = (struct die_args *)data;
720 switch(val) {
721 case DIE_BREAK:
89cb14c0 722 if (pre_kprobes_handler(args))
fd7b231f
AK		 723 return NOTIFY_STOP;
724 break;
725 case DIE_SS:
726 if (post_kprobes_handler(args->regs))
727 return NOTIFY_STOP;
728 break;
729 case DIE_PAGE_FAULT:
730 if (kprobes_fault_handler(args->regs, args->trapnr))
731 return NOTIFY_STOP;
732 default:
733 break;
734 }
735 return NOTIFY_DONE;
736}
737
1f7ad57b 738int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
fd7b231f 739{
b2761dc2
AK		 740 struct jprobe *jp = container_of(p, struct jprobe, kp);
741 unsigned long addr = ((struct fnptr *)(jp->entry))->ip;
fd7b231f 742
b2761dc2
AK		 743 /* save architectural state */
744 jprobe_saved_regs = *regs;
745
746 /* after rfi, execute the jprobe instrumented function */
747 regs->cr_iip = addr & ~0xFULL;
748 ia64_psr(regs)->ri = addr & 0xf;
749 regs->r1 = ((struct fnptr *)(jp->entry))->gp;
750
751 /*
752 * fix the return address to our jprobe_inst_return() function
753 * in the jprobes.S file
754 */
755 regs->b0 = ((struct fnptr *)(jprobe_inst_return))->ip;
756
757 return 1;
fd7b231f
AK		 758}
759
1f7ad57b 760int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
fd7b231f 761{
b2761dc2
AK		 762 *regs = jprobe_saved_regs;
763 return 1;
fd7b231f 764}
9508dbfe
RL		 765
766static struct kprobe trampoline_p = {
767 .pre_handler = trampoline_probe_handler
768};
769
6772926b 770int __init arch_init_kprobes(void)
9508dbfe
RL		 771{
772 trampoline_p.addr =
773 (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip;
774 return register_kprobe(&trampoline_p);
775}
Linux kernel - Deliverables
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