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} 1130