kprobe/arch/asm-arm/dbi_kprobes.c

   1 /*
   2  *  Dynamic Binary Instrumentation Module based on KProbes
   3  *  modules/kprobe/arch/asm-arm/dbi_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) Samsung Electronics, 2006-2010
  20  *
  21  * 2006-2007    Ekaterina Gorelkina <e.gorelkina@samsung.com>: initial implementation for ARM/MIPS
  22  * 2008-2009    Alexey Gerenkov <a.gerenkov@samsung.com> User-Space
  23  *              Probes initial implementation; Support x86.
  24  * 2010         Ekaterina Gorelkina <e.gorelkina@samsung.com>: redesign module for separating core and arch parts
  25  * 2010-2011    Alexander Shirshikov <a.shirshikov@samsung.com>: initial implementation for Thumb
  26  * 2012         Stanislav Andreev <s.andreev@samsung.com>: added time debug profiling support; BUG() message fix
  27  * 2012         Stanislav Andreev <s.andreev@samsung.com>: redesign of kprobe functionality -
  28  *              kprobe_handler() now called via undefined instruction hooks
  29  * 2012         Stanislav Andreev <s.andreev@samsung.com>: hash tables search implemented for uprobes
  30  */
  31
  32 #include <linux/module.h>
  33 #include <linux/mm.h>
  34
  35 #include "dbi_kprobes.h"
  36 #include "dbi_kprobes_arm.h"
  37 #include "dbi_kprobes_thumb.h"
  38 #include "../dbi_kprobes.h"
  39 #include "../../dbi_kprobes.h"
  40
  41 #include "../../dbi_kdebug.h"
  42 #include "../../dbi_insn_slots.h"
  43 #include "../../dbi_kprobes_deps.h"
  44 #include <ksyms.h>
  45
  46 #include <asm/cacheflush.h>
  47
  48 #ifdef TRAP_OVERHEAD_DEBUG
  49 #include <linux/pid.h>
  50 #include <linux/signal.h>
  51 #endif
  52
  53 #ifdef OVERHEAD_DEBUG
  54 #include <linux/time.h>
  55 #endif
  56
  57 #include <asm/traps.h>
  58 #include <asm/ptrace.h>
  59 #include <linux/list.h>
  60 #include <linux/hash.h>
  61
  62 #define SUPRESS_BUG_MESSAGES
  63
  64 extern struct kprobe * per_cpu__current_kprobe;
  65 extern struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
  66
  67 static void (*__swap_register_undef_hook)(struct undef_hook *hook);
  68 static void (*__swap_unregister_undef_hook)(struct undef_hook *hook);
  69
  70 #ifdef OVERHEAD_DEBUG
  71 unsigned long swap_sum_time = 0;
  72 unsigned long swap_sum_hit = 0;
  73 EXPORT_SYMBOL_GPL (swap_sum_time);
  74 EXPORT_SYMBOL_GPL (swap_sum_hit);
  75 #endif
  76
  77 static unsigned int arr_traps_template[] = {
  78                 0xe1a0c00d,    // mov          ip, sp
  79                 0xe92dd800,    // stmdb        sp!, {fp, ip, lr, pc}
  80                 0xe24cb004,    // sub          fp, ip, #4      ; 0x4
  81                 0x00000000,    // b
  82                 0xe3500000,    // cmp          r0, #0  ; 0x0
  83                 0xe89da800,    // ldmia        sp, {fp, sp, pc}
  84                 0x00000000,    // nop
  85                 0xffffffff     // end
  86 };
  87
  88
  89 static struct kprobe trampoline_p =
  90 {
  91         .addr = (kprobe_opcode_t *) & kretprobe_trampoline,
  92         .pre_handler = trampoline_probe_handler
  93 };
  94
  95 // is instruction Thumb2 and NOT a branch, etc...
  96 int isThumb2(kprobe_opcode_t insn)
  97 {
  98         if((    (insn & 0xf800) == 0xe800 ||
  99                 (insn & 0xf800) == 0xf000 ||
 100                 (insn & 0xf800) == 0xf800)) return 1;
 101         return 0;
 102 }
 103 EXPORT_SYMBOL_GPL(isThumb2);
 104
 105 int prep_pc_dep_insn_execbuf(kprobe_opcode_t *insns, kprobe_opcode_t insn, int uregs)
 106 {
 107         int i;
 108
 109         if (uregs & 0x10)
 110         {
 111                 int reg_mask = 0x1;
 112                 //search in reg list
 113                 for (i = 0; i < 13; i++, reg_mask <<= 1)
 114                 {
 115                         if (!(insn & reg_mask))
 116                                 break;
 117                 }
 118         }
 119         else
 120         {
 121                 for (i = 0; i < 13; i++)
 122                 {
 123                         if ((uregs & 0x1) && (ARM_INSN_REG_RN (insn) == i))
 124                                 continue;
 125                         if ((uregs & 0x2) && (ARM_INSN_REG_RD (insn) == i))
 126                                 continue;
 127                         if ((uregs & 0x4) && (ARM_INSN_REG_RS (insn) == i))
 128                                 continue;
 129                         if ((uregs & 0x8) && (ARM_INSN_REG_RM (insn) == i))
 130                                 continue;
 131                         break;
 132                 }
 133         }
 134         if (i == 13)
 135         {
 136                 DBPRINTF ("there are no free register %x in insn %lx!", uregs, insn);
 137                 return -EINVAL;
 138         }
 139         DBPRINTF ("prep_pc_dep_insn_execbuf: using R%d, changing regs %x", i, uregs);
 140
 141         // set register to save
 142         ARM_INSN_REG_SET_RD (insns[0], i);
 143         // set register to load address to
 144         ARM_INSN_REG_SET_RD (insns[1], i);
 145         // set instruction to execute and patch it
 146         if (uregs & 0x10)
 147         {
 148                 ARM_INSN_REG_CLEAR_MR (insn, 15);
 149                 ARM_INSN_REG_SET_MR (insn, i);
 150         }
 151         else
 152         {
 153                 if ((uregs & 0x1) && (ARM_INSN_REG_RN (insn) == 15))
 154                         ARM_INSN_REG_SET_RN (insn, i);
 155                 if ((uregs & 0x2) && (ARM_INSN_REG_RD (insn) == 15))
 156                         ARM_INSN_REG_SET_RD (insn, i);
 157                 if ((uregs & 0x4) && (ARM_INSN_REG_RS (insn) == 15))
 158                         ARM_INSN_REG_SET_RS (insn, i);
 159                 if ((uregs & 0x8) && (ARM_INSN_REG_RM (insn) == 15))
 160                         ARM_INSN_REG_SET_RM (insn, i);
 161         }
 162         insns[UPROBES_TRAMP_INSN_IDX] = insn;
 163         // set register to restore
 164         ARM_INSN_REG_SET_RD (insns[3], i);
 165         return 0;
 166 }
 167 EXPORT_SYMBOL_GPL(prep_pc_dep_insn_execbuf);
 168
 169 int arch_check_insn_arm(struct arch_specific_insn *ainsn)
 170 {
 171         int ret = 0;
 172
 173         // check instructions that can change PC by nature
 174         if (
 175 //              ARM_INSN_MATCH (UNDEF, ainsn->insn_arm[0]) ||
 176                 ARM_INSN_MATCH (AUNDEF, ainsn->insn_arm[0]) ||
 177                 ARM_INSN_MATCH (SWI, ainsn->insn_arm[0]) ||
 178                 ARM_INSN_MATCH (BREAK, ainsn->insn_arm[0]) ||
 179                 ARM_INSN_MATCH (BL, ainsn->insn_arm[0]) ||
 180                 ARM_INSN_MATCH (BLX1, ainsn->insn_arm[0]) ||
 181                 ARM_INSN_MATCH (BLX2, ainsn->insn_arm[0]) ||
 182                 ARM_INSN_MATCH (BX, ainsn->insn_arm[0]) ||
 183                 ARM_INSN_MATCH (BXJ, ainsn->insn_arm[0]))
 184         {
 185                 DBPRINTF ("Bad insn arch_check_insn_arm: %lx\n", ainsn->insn_arm[0]);
 186                 ret = -EFAULT;
 187         }
 188 #ifndef CONFIG_CPU_V7
 189         // check instructions that can write result to PC
 190         else if ((ARM_INSN_MATCH (DPIS, ainsn->insn_arm[0]) ||
 191                                 ARM_INSN_MATCH (DPRS, ainsn->insn_arm[0]) ||
 192                                 ARM_INSN_MATCH (DPI, ainsn->insn_arm[0]) ||
 193                                 ARM_INSN_MATCH (LIO, ainsn->insn_arm[0]) ||
 194                                 ARM_INSN_MATCH (LRO, ainsn->insn_arm[0])) &&
 195                         (ARM_INSN_REG_RD (ainsn->insn_arm[0]) == 15))
 196         {
 197                 DBPRINTF ("Bad arch_check_insn_arm: %lx\n", ainsn->insn_arm[0]);
 198                 ret = -EFAULT;
 199         }
 200 #endif // CONFIG_CPU_V7
 201         // check special instruction loads store multiple registers
 202         else if ((ARM_INSN_MATCH (LM, ainsn->insn_arm[0]) || ARM_INSN_MATCH (SM, ainsn->insn_arm[0])) &&
 203                         // store pc or load to pc
 204                         (ARM_INSN_REG_MR (ainsn->insn_arm[0], 15) ||
 205                          // store/load with pc update
 206                          ((ARM_INSN_REG_RN (ainsn->insn_arm[0]) == 15) && (ainsn->insn_arm[0] & 0x200000))))
 207         {
 208                 DBPRINTF ("Bad insn arch_check_insn_arm: %lx\n", ainsn->insn_arm[0]);
 209                 ret = -EFAULT;
 210         }
 211         return ret;
 212 }
 213 EXPORT_SYMBOL_GPL(arch_check_insn_arm);
 214
 215 int arch_prepare_kretprobe (struct kretprobe *p)
 216 {
 217         DBPRINTF("Warrning: arch_prepare_kretprobe is not implemented\n");
 218         return 0;
 219 }
 220
 221 int arch_prepare_kprobe (struct kprobe *p)
 222 {
 223         kprobe_opcode_t insns[KPROBES_TRAMP_LEN];
 224         int uregs, pc_dep, ret = 0;
 225     kprobe_opcode_t insn[MAX_INSN_SIZE];
 226     struct arch_specific_insn ainsn;
 227
 228     /* insn: must be on special executable page on i386. */
 229     p->ainsn.insn = get_insn_slot (NULL, 0);
 230     if (!p->ainsn.insn)
 231         return -ENOMEM;
 232
 233     memcpy (insn, p->addr, MAX_INSN_SIZE * sizeof (kprobe_opcode_t));
 234     ainsn.insn_arm = ainsn.insn = insn;
 235     ret = arch_check_insn_arm (&ainsn);
 236     if (!ret)
 237     {
 238         p->opcode = *p->addr;
 239         uregs = pc_dep = 0;
 240
 241         // Rn, Rm ,Rd
 242         if(ARM_INSN_MATCH (DPIS, insn[0]) || ARM_INSN_MATCH (LRO, insn[0]) ||
 243            ARM_INSN_MATCH (SRO, insn[0]))
 244         {
 245             uregs = 0xb;
 246             if( (ARM_INSN_REG_RN (insn[0]) == 15) || (ARM_INSN_REG_RM (insn[0]) == 15) ||
 247                 (ARM_INSN_MATCH (SRO, insn[0]) && (ARM_INSN_REG_RD (insn[0]) == 15)) )
 248             {
 249                 DBPRINTF ("Unboostable insn %lx, DPIS/LRO/SRO\n", insn[0]);
 250                 pc_dep = 1;
 251             }
 252         }
 253         // Rn ,Rd
 254         else if(ARM_INSN_MATCH (DPI, insn[0]) || ARM_INSN_MATCH (LIO, insn[0]) ||
 255                 ARM_INSN_MATCH (SIO, insn[0]))
 256         {
 257             uregs = 0x3;
 258             if ((ARM_INSN_REG_RN (insn[0]) == 15) || (ARM_INSN_MATCH (SIO, insn[0]) &&
 259                         (ARM_INSN_REG_RD (insn[0]) == 15)))
 260             {
 261                 pc_dep = 1;
 262                 DBPRINTF ("Unboostable insn %lx/%p, DPI/LIO/SIO\n", insn[0], p);
 263             }
 264         }
 265         // Rn, Rm, Rs
 266         else if(ARM_INSN_MATCH (DPRS, insn[0]))
 267         {
 268             uregs = 0xd;
 269             if ((ARM_INSN_REG_RN (insn[0]) == 15) || (ARM_INSN_REG_RM (insn[0]) == 15) ||
 270                 (ARM_INSN_REG_RS (insn[0]) == 15))
 271             {
 272                 pc_dep = 1;
 273                 DBPRINTF ("Unboostable insn %lx, DPRS\n", insn[0]);
 274             }
 275         }
 276         // register list
 277         else if(ARM_INSN_MATCH (SM, insn[0]))
 278         {
 279             uregs = 0x10;
 280             if (ARM_INSN_REG_MR (insn[0], 15))
 281             {
 282                 DBPRINTF ("Unboostable insn %lx, SM\n", insn[0]);
 283                 pc_dep = 1;
 284             }
 285         }
 286         // check instructions that can write result to SP andu uses PC
 287         if (pc_dep  && (ARM_INSN_REG_RD (ainsn.insn[0]) == 13))
 288         {
 289             free_insn_slot(&kprobe_insn_pages, NULL, p->ainsn.insn);
 290             ret = -EFAULT;
 291         }
 292         else
 293         {
 294             if (uregs && pc_dep)
 295             {
 296                 memcpy (insns, pc_dep_insn_execbuf, sizeof (insns));
 297                 if (prep_pc_dep_insn_execbuf (insns, insn[0], uregs) != 0)
 298                 {
 299                     DBPRINTF ("failed to prepare exec buffer for insn %lx!", insn[0]);
 300                     free_insn_slot(&kprobe_insn_pages, NULL, p->ainsn.insn);
 301                     return -EINVAL;
 302                 }
 303                 insns[6] = (kprobe_opcode_t) (p->addr + 2);
 304             }
 305             else
 306             {
 307                 memcpy (insns, gen_insn_execbuf, sizeof (insns));
 308                 insns[KPROBES_TRAMP_INSN_IDX] = insn[0];
 309             }
 310             insns[7] = (kprobe_opcode_t) (p->addr + 1);
 311             DBPRINTF ("arch_prepare_kprobe: insn %lx", insn[0]);
 312             DBPRINTF ("arch_prepare_kprobe: to %p - %lx %lx %lx %lx %lx %lx %lx %lx %lx",
 313                     p->ainsn.insn, insns[0], insns[1], insns[2], insns[3], insns[4],
 314                     insns[5], insns[6], insns[7], insns[8]);
 315             memcpy (p->ainsn.insn, insns, sizeof(insns));
 316             flush_icache_range((long unsigned)p->ainsn.insn, (long unsigned)(p->ainsn.insn) + sizeof(insns));
 317 #ifdef BOARD_tegra
 318             flush_cache_all();
 319 #endif
 320         }
 321     }
 322     else
 323     {
 324         free_insn_slot(&kprobe_insn_pages, NULL, p->ainsn.insn);
 325         printk("arch_prepare_kprobe: instruction 0x%lx not instrumentation, addr=0x%p\n", insn[0], p->addr);
 326     }
 327
 328     return ret;
 329 }
 330
 331 static unsigned int arch_construct_brunch (unsigned int base, unsigned int addr, int link)
 332 {
 333         kprobe_opcode_t insn;
 334         unsigned int bpi = (unsigned int) base - (unsigned int) addr - 8;
 335
 336         insn = bpi >> 2;
 337         DBPRINTF ("base=%x addr=%x base-addr-8=%x\n", base, addr, bpi);
 338         if (abs (insn & 0xffffff) > 0xffffff)
 339         {
 340                 DBPRINTF ("ERROR: kprobe address out of range\n");
 341                 BUG ();
 342         }
 343         insn = insn & 0xffffff;
 344         insn = insn | ((link != 0) ? 0xeb000000 : 0xea000000);
 345         DBPRINTF ("insn=%lX\n", insn);
 346         return (unsigned int) insn;
 347 }
 348
 349 int arch_prepare_uretprobe (struct kretprobe *p, struct task_struct *task)
 350 {
 351         DBPRINTF("Warrning: arch_prepare_uretprobe is not implemented\n");
 352         return 0;
 353 }
 354 EXPORT_SYMBOL_GPL(arch_prepare_uretprobe);
 355
 356 void prepare_singlestep (struct kprobe *p, struct pt_regs *regs)
 357 {
 358         if (p->ss_addr) {
 359                 regs->ARM_pc = (unsigned long)p->ss_addr;
 360                 p->ss_addr = NULL;
 361         } else {
 362                 regs->ARM_pc = (unsigned long)p->ainsn.insn;
 363         }
 364 }
 365
 366 void save_previous_kprobe(struct kprobe_ctlblk *kcb, struct kprobe *p_run)
 367 {
 368         if (p_run == NULL) {
 369                 panic("arm_save_previous_kprobe: p_run == NULL\n");
 370         }
 371
 372         if (kcb->prev_kprobe.kp != NULL) {
 373                 DBPRINTF ("no space to save new probe[]: task = %d/%s", current->pid, current->comm);
 374         }
 375
 376         kcb->prev_kprobe.kp = p_run;
 377         kcb->prev_kprobe.status = kcb->kprobe_status;
 378 }
 379
 380 void restore_previous_kprobe(struct kprobe_ctlblk *kcb)
 381 {
 382         set_current_kprobe(kcb->prev_kprobe.kp, NULL, NULL);
 383         kcb->kprobe_status = kcb->prev_kprobe.status;
 384         kcb->prev_kprobe.kp = NULL;
 385         kcb->prev_kprobe.status = 0;
 386 }
 387
 388 void set_current_kprobe(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb)
 389 {
 390         __get_cpu_var(current_kprobe) = p;
 391         DBPRINTF ("set_current_kprobe: p=%p addr=%p\n", p, p->addr);
 392 }
 393
 394 static int check_validity_insn(struct kprobe *p, struct pt_regs *regs, struct task_struct *task)
 395 {
 396         struct kprobe *kp;
 397
 398         if (unlikely(thumb_mode(regs))) {
 399                 if (p->safe_thumb != -1) {
 400                         p->ainsn.insn = p->ainsn.insn_thumb;
 401                         list_for_each_entry_rcu(kp, &p->list, list) {
 402                                 kp->ainsn.insn = p->ainsn.insn_thumb;
 403                         }
 404                 } else {
 405                         printk("Error in %s at %d: we are in thumb mode (!) and check instruction was fail \
 406                                 (%0lX instruction at %p address)!\n", __FILE__, __LINE__, p->opcode, p->addr);
 407                         // Test case when we do our actions on already running application
 408                         arch_disarm_uprobe(p, task);
 409                         return -1;
 410                 }
 411         } else {
 412                 if (p->safe_arm != -1) {
 413                         p->ainsn.insn = p->ainsn.insn_arm;
 414                         list_for_each_entry_rcu(kp, &p->list, list) {
 415                                 kp->ainsn.insn = p->ainsn.insn_arm;
 416                         }
 417                 } else {
 418                         printk("Error in %s at %d: we are in arm mode (!) and check instruction was fail \
 419                                 (%0lX instruction at %p address)!\n", __FILE__, __LINE__, p->opcode, p->addr);
 420                         // Test case when we do our actions on already running application
 421                         arch_disarm_uprobe(p, task);
 422                         return -1;
 423                 }
 424         }
 425
 426         return 0;
 427 }
 428
 429 #ifdef TRAP_OVERHEAD_DEBUG
 430 static unsigned long trap_handler_counter_debug = 0;
 431 #define SAMPLING_COUNTER                               100000
 432 #endif
 433
 434 static int kprobe_handler(struct pt_regs *regs)
 435 {
 436         int err_out = 0;
 437         char *msg_out = NULL;
 438         unsigned long user_m = user_mode(regs);
 439         pid_t tgid = (user_m) ? current->tgid : 0;
 440         kprobe_opcode_t *addr = (kprobe_opcode_t *) (regs->ARM_pc);
 441
 442         struct kprobe *p = NULL, *p_run = NULL;
 443         int ret = 0, retprobe = 0, reenter = 0;
 444         kprobe_opcode_t *ssaddr = NULL;
 445         struct kprobe_ctlblk *kcb;
 446
 447 #ifdef SUPRESS_BUG_MESSAGES
 448         int swap_oops_in_progress;
 449         // oops_in_progress used to avoid BUG() messages that slow down kprobe_handler() execution
 450         swap_oops_in_progress = oops_in_progress;
 451         oops_in_progress = 1;
 452 #endif
 453 #ifdef TRAP_OVERHEAD_DEBUG
 454         trap_handler_counter_debug++;
 455         if ( trap_handler_counter_debug < SAMPLING_COUNTER ) {
 456                 err_out = 0;
 457         }
 458         else {
 459                 // XXX NOTE - user must care about catching signal via signal handler to avoid hanging!
 460                 printk("Trap %ld reached - send SIGUSR1\n", trap_handler_counter_debug);
 461                 kill_pid(get_task_pid(current, PIDTYPE_PID), SIGUSR1, 1);
 462                 trap_handler_counter_debug = 0;
 463                 err_out = 0;
 464         }
 465         return err_out;
 466 #endif
 467 #ifdef OVERHEAD_DEBUG
 468         struct timeval swap_tv1;
 469         struct timeval swap_tv2;
 470 #define USEC_IN_SEC_NUM                         1000000
 471         do_gettimeofday(&swap_tv1);
 472 #endif
 473         preempt_disable();
 474
 475 //      printk("### kprobe_handler: task[tgid=%u (%s)] addr=%p\n", tgid, current->comm, addr);
 476         p = get_kprobe(addr, tgid);
 477
 478         if (user_m && p && (check_validity_insn(p, regs, current) != 0)) {
 479                 goto no_kprobe_live;
 480         }
 481
 482         /* We're in an interrupt, but this is clear and BUG()-safe. */
 483         kcb = get_kprobe_ctlblk ();
 484
 485         /* Check we're not actually recursing */
 486         // TODO: event is not saving in trace
 487         p_run = kprobe_running();
 488         if (p_run)
 489         {
 490                 DBPRINTF("lock???");
 491                 if (p)
 492                 {
 493                         if (!tgid && (addr == (kprobe_opcode_t *)kretprobe_trampoline)) {
 494                                 save_previous_kprobe(kcb, p_run);
 495                                 kcb->kprobe_status = KPROBE_REENTER;
 496                                 reenter = 1;
 497                         } else {
 498                                 /* We have reentered the kprobe_handler(), since
 499                                  * another probe was hit while within the handler.
 500                                  * We here save the original kprobes variables and
 501                                  * just single step on the instruction of the new probe
 502                                  * without calling any user handlers.
 503                                  */
 504                                 kprobes_inc_nmissed_count (p);
 505                                 prepare_singlestep (p, regs);
 506
 507                                 err_out = 0;
 508                                 goto out;
 509                         }
 510                 } else {
 511                         if(tgid) { //we can reenter probe upon uretprobe exception
 512                                 DBPRINTF ("check for UNDEF_INSTRUCTION %p\n", addr);
 513                                 // UNDEF_INSTRUCTION from user space
 514
 515                                 p = get_kprobe_by_insn_slot(addr, tgid, regs);
 516                                 if (p) {
 517                                         save_previous_kprobe(kcb, p_run);
 518                                         kcb->kprobe_status = KPROBE_REENTER;
 519                                         reenter = 1;
 520                                         retprobe = 1;
 521                                         DBPRINTF ("uretprobe %p\n", addr);
 522                                 }
 523                         }
 524                         if(!p) {
 525                                 p = p_run;
 526                                 DBPRINTF ("kprobe_running !!! p = 0x%p p->break_handler = 0x%p", p, p->break_handler);
 527                                 /*if (p->break_handler && p->break_handler(p, regs)) {
 528                                   DBPRINTF("kprobe_running !!! goto ss");
 529                                   goto ss_probe;
 530                                   } */
 531                                 DBPRINTF ("unknown uprobe at %p cur at %p/%p\n", addr, p->addr, p->ainsn.insn);
 532                                 if (tgid)
 533                                         ssaddr = p->ainsn.insn + UPROBES_TRAMP_SS_BREAK_IDX;
 534                                 else
 535                                         ssaddr = p->ainsn.insn + KPROBES_TRAMP_SS_BREAK_IDX;
 536                                 if (addr == ssaddr) {
 537                                         regs->ARM_pc = (unsigned long) (p->addr + 1);
 538                                         DBPRINTF ("finish step at %p cur at %p/%p, redirect to %lx\n", addr, p->addr, p->ainsn.insn, regs->ARM_pc);
 539                                         if (kcb->kprobe_status == KPROBE_REENTER) {
 540                                                 restore_previous_kprobe(kcb);
 541                                         } else {
 542                                                 reset_current_kprobe();
 543                                         }
 544                                 }
 545                                 DBPRINTF ("kprobe_running !!! goto no");
 546                                 ret = 1;
 547                                 /* If it's not ours, can't be delete race, (we hold lock). */
 548                                 DBPRINTF ("no_kprobe");
 549                                 goto no_kprobe;
 550                         }
 551                 }
 552         }
 553
 554         if (!p) {
 555                 if (tgid) {
 556                         DBPRINTF ("search UNDEF_INSTRUCTION %p\n", addr);
 557                         // UNDEF_INSTRUCTION from user space
 558
 559                         p = get_kprobe_by_insn_slot(addr, tgid, regs);
 560                         if (!p) {
 561                                 /* Not one of ours: let kernel handle it */
 562                                 DBPRINTF ("no_kprobe");
 563                                 goto no_kprobe;
 564                         }
 565                         retprobe = 1;
 566                         DBPRINTF ("uretprobe %p\n", addr);
 567                 } else {
 568                         /* Not one of ours: let kernel handle it */
 569                         DBPRINTF ("no_kprobe");
 570                         goto no_kprobe;
 571                 }
 572         }
 573         // restore opcode for thumb app
 574         if (user_mode( regs ) && thumb_mode( regs )) {
 575                 if (!isThumb2(p->opcode)) {
 576                         unsigned long tmp = p->opcode >> 16;
 577                         write_proc_vm_atomic(current, (unsigned long)((unsigned short*)p->addr + 1), &tmp, 2);
 578
 579                         // "2*sizeof(kprobe_opcode_t)" - strange. Should be "sizeof(kprobe_opcode_t)", need to test
 580                         flush_icache_range((unsigned int) p->addr, ((unsigned int)p->addr) + (2 * sizeof(kprobe_opcode_t)));
 581                 }
 582         }
 583         set_current_kprobe(p, NULL, NULL);
 584         if(!reenter)
 585                 kcb->kprobe_status = KPROBE_HIT_ACTIVE;
 586         if (retprobe) {         //(einsn == UNDEF_INSTRUCTION)
 587                 ret = trampoline_probe_handler (p, regs);
 588         } else if (p->pre_handler) {
 589                 ret = p->pre_handler (p, regs);
 590                 if(p->pre_handler != trampoline_probe_handler) {
 591                         reset_current_kprobe();
 592                 }
 593         }
 594
 595         if (ret) {
 596                 /* handler has already set things up, so skip ss setup */
 597                 err_out = 0;
 598                 goto out;
 599         }
 600
 601 no_kprobe:
 602         msg_out = "no_kprobe\n";
 603         err_out = 1;            // return with death
 604         goto out;
 605
 606 no_kprobe_live:
 607         msg_out = "no_kprobe live\n";
 608         err_out = 0;            // ok - life is life
 609         goto out;
 610
 611 out:
 612         preempt_enable_no_resched();
 613 #ifdef OVERHEAD_DEBUG
 614         do_gettimeofday(&swap_tv2);
 615         swap_sum_hit++;
 616         swap_sum_time += ((swap_tv2.tv_sec - swap_tv1.tv_sec) *  USEC_IN_SEC_NUM +
 617                 (swap_tv2.tv_usec - swap_tv1.tv_usec));
 618 #endif
 619 #ifdef SUPRESS_BUG_MESSAGES
 620         oops_in_progress = swap_oops_in_progress;
 621 #endif
 622
 623         if(msg_out) {
 624                 printk(msg_out);
 625         }
 626
 627         return err_out;
 628 }
 629
 630 int kprobe_trap_handler(struct pt_regs *regs, unsigned int instr)
 631 {
 632         int ret;
 633         unsigned long flags;
 634         local_irq_save(flags);
 635         ret = kprobe_handler(regs);
 636         local_irq_restore(flags);
 637         return ret;
 638 }
 639 EXPORT_SYMBOL_GPL(kprobe_trap_handler);
 640
 641 int setjmp_pre_handler (struct kprobe *p, struct pt_regs *regs)
 642 {
 643         struct jprobe *jp = container_of (p, struct jprobe, kp);
 644         kprobe_pre_entry_handler_t pre_entry;
 645         entry_point_t entry;
 646
 647 # ifdef REENTER
 648 //      p = kprobe_running(regs);
 649 # endif
 650
 651         DBPRINTF ("pjp = 0x%p jp->entry = 0x%p", jp, jp->entry);
 652         entry = (entry_point_t) jp->entry;
 653         pre_entry = (kprobe_pre_entry_handler_t) jp->pre_entry;
 654         //if(!entry)
 655         //      DIE("entry NULL", regs)
 656         DBPRINTF ("entry = 0x%p jp->entry = 0x%p", entry, jp->entry);
 657
 658         //call handler for all kernel probes and user space ones which belong to current tgid
 659         if (!p->tgid || (p->tgid == current->tgid))
 660         {
 661                 if(!p->tgid && ((unsigned int)p->addr == sched_addr) && sched_rp) {
 662                         struct thread_info *tinfo = (struct thread_info *)regs->ARM_r2;
 663                         patch_suspended_task(sched_rp, tinfo->task);
 664                 }
 665                 if (pre_entry)
 666                         p->ss_addr = (void *)pre_entry (jp->priv_arg, regs);
 667                 if (entry){
 668                         entry (regs->ARM_r0, regs->ARM_r1, regs->ARM_r2, regs->ARM_r3, regs->ARM_r4, regs->ARM_r5);
 669                 }
 670                 else {
 671                         if (p->tgid)
 672                                 dbi_arch_uprobe_return ();
 673                         else
 674                                 dbi_jprobe_return ();
 675                 }
 676         }
 677         else if (p->tgid)
 678                 dbi_arch_uprobe_return ();
 679
 680         prepare_singlestep (p, regs);
 681
 682         return 1;
 683 }
 684 EXPORT_SYMBOL_GPL(setjmp_pre_handler);
 685
 686 void dbi_jprobe_return (void)
 687 {
 688 }
 689
 690 void dbi_arch_uprobe_return (void)
 691 {
 692 }
 693 EXPORT_SYMBOL_GPL(dbi_arch_uprobe_return);
 694
 695 int longjmp_break_handler (struct kprobe *p, struct pt_regs *regs)
 696 {
 697 # ifndef REENTER
 698         //kprobe_opcode_t insn = BREAKPOINT_INSTRUCTION;
 699         kprobe_opcode_t insns[2];
 700
 701         if (p->pid)
 702         {
 703                 insns[0] = BREAKPOINT_INSTRUCTION;
 704                 insns[1] = p->opcode;
 705                 //p->opcode = *p->addr;
 706                 if (read_proc_vm_atomic (current, (unsigned long) (p->addr), &(p->opcode), sizeof (p->opcode)) < sizeof (p->opcode))
 707                 {
 708                         printk ("ERROR[%lu]: failed to read vm of proc %s/%u addr %p.", nCount, current->comm, current->pid, p->addr);
 709                         return -1;
 710                 }
 711                 //*p->addr = BREAKPOINT_INSTRUCTION;
 712                 //*(p->addr+1) = p->opcode;
 713                 if (write_proc_vm_atomic (current, (unsigned long) (p->addr), insns, sizeof (insns)) < sizeof (insns))
 714                 {
 715                         printk ("ERROR[%lu]: failed to write vm of proc %s/%u addr %p.", nCount, current->comm, current->pid, p->addr);
 716                         return -1;
 717                 }
 718         }
 719         else
 720         {
 721                 DBPRINTF ("p->opcode = 0x%lx *p->addr = 0x%lx p->addr = 0x%p\n", p->opcode, *p->addr, p->addr);
 722                 *(p->addr + 1) = p->opcode;
 723                 p->opcode = *p->addr;
 724                 *p->addr = BREAKPOINT_INSTRUCTION;
 725
 726                 flush_icache_range ((unsigned int) p->addr, (unsigned int) (((unsigned int) p->addr) + (sizeof (kprobe_opcode_t) * 2)));
 727         }
 728
 729         reset_current_kprobe();
 730
 731 #endif //REENTER
 732
 733         return 0;
 734 }
 735 EXPORT_SYMBOL_GPL(longjmp_break_handler);
 736
 737 void arch_arm_kprobe (struct kprobe *p)
 738 {
 739         *p->addr = BREAKPOINT_INSTRUCTION;
 740         flush_icache_range ((unsigned long) p->addr, (unsigned long) p->addr + sizeof (kprobe_opcode_t));
 741 }
 742
 743 void arch_disarm_kprobe (struct kprobe *p)
 744 {
 745         *p->addr = p->opcode;
 746         flush_icache_range ((unsigned long) p->addr, (unsigned long) p->addr + sizeof (kprobe_opcode_t));
 747 }
 748
 749
 750 int trampoline_probe_handler (struct kprobe *p, struct pt_regs *regs)
 751 {
 752         struct kretprobe_instance *ri = NULL;
 753         struct hlist_head *head;
 754         struct hlist_node *node, *tmp;
 755         unsigned long flags, orig_ret_address = 0;
 756         unsigned long trampoline_address = (unsigned long) &kretprobe_trampoline;
 757
 758         struct kretprobe *crp = NULL;
 759         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk ();
 760
 761         DBPRINTF ("start");
 762
 763         if (p && p->tgid){
 764                 // in case of user space retprobe trampoline is at the Nth instruction of US tramp
 765                 if (!thumb_mode( regs ))
 766                         trampoline_address = (unsigned long)(p->ainsn.insn + UPROBES_TRAMP_RET_BREAK_IDX);
 767                 else
 768                         trampoline_address = (unsigned long)(p->ainsn.insn) + 0x1b;
 769         }
 770
 771         spin_lock_irqsave (&kretprobe_lock, flags);
 772
 773         /*
 774          * We are using different hash keys (current and mm) for finding kernel
 775          * space and user space probes.  Kernel space probes can change mm field in
 776          * task_struct.  User space probes can be shared between threads of one
 777          * process so they have different current but same mm.
 778          */
 779         if (p && p->tgid) {
 780                 head = kretprobe_inst_table_head(current->mm);
 781         } else {
 782                 head = kretprobe_inst_table_head(current);
 783         }
 784
 785         /*
 786          * It is possible to have multiple instances associated with a given
 787          * task either because an multiple functions in the call path
 788          * have a return probe installed on them, and/or more then one
 789          * return probe was registered for a target function.
 790          *
 791          * We can handle this because:
 792          *     - instances are always inserted at the head of the list
 793          *     - when multiple return probes are registered for the same
 794          *       function, the first instance's ret_addr will point to the
 795          *       real return address, and all the rest will point to
 796          *       kretprobe_trampoline
 797          */
 798         hlist_for_each_entry_safe (ri, node, tmp, head, hlist)
 799         {
 800                 if (ri->task != current)
 801                         /* another task is sharing our hash bucket */
 802                         continue;
 803                 if (ri->rp && ri->rp->handler){
 804                         ri->rp->handler (ri, regs, ri->rp->priv_arg);
 805                 }
 806
 807                 orig_ret_address = (unsigned long) ri->ret_addr;
 808                 recycle_rp_inst (ri);
 809                 if (orig_ret_address != trampoline_address)
 810                         /*
 811                          * This is the real return address. Any other
 812                          * instances associated with this task are for
 813                          * other calls deeper on the call stack
 814                          */
 815                         break;
 816         }
 817         kretprobe_assert (ri, orig_ret_address, trampoline_address);
 818         //BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address));
 819         //E.G. Check this code in case of __switch_to function instrumentation -- currently this code generates dump in this case
 820         //if (trampoline_address != (unsigned long) &kretprobe_trampoline){
 821         //if (ri->rp2) BUG_ON (ri->rp2->kp.tgid == 0);
 822         //if (ri->rp) BUG_ON (ri->rp->kp.tgid == 0);
 823         //else if (ri->rp2) BUG_ON (ri->rp2->kp.tgid == 0);
 824         //}
 825         if ((ri->rp && ri->rp->kp.tgid) || (ri->rp2 && ri->rp2->kp.tgid))
 826                 BUG_ON (trampoline_address == (unsigned long) &kretprobe_trampoline);
 827
 828         regs->uregs[14] = orig_ret_address;
 829         DBPRINTF ("regs->uregs[14] = 0x%lx\n", regs->uregs[14]);
 830         DBPRINTF ("regs->uregs[15] = 0x%lx\n", regs->uregs[15]);
 831
 832         if (trampoline_address != (unsigned long) &kretprobe_trampoline)
 833         {
 834                 regs->uregs[15] = orig_ret_address;
 835         }else{
 836                 if (!thumb_mode( regs )) regs->uregs[15] += 4;
 837                 else regs->uregs[15] += 2;
 838         }
 839
 840         DBPRINTF ("regs->uregs[15] = 0x%lx\n", regs->uregs[15]);
 841
 842         if(p){ // ARM, MIPS, X86 user space
 843                 if (thumb_mode( regs ) && !(regs->uregs[14] & 0x01))
 844                 {
 845                         regs->ARM_cpsr &= 0xFFFFFFDF;
 846                 }else{
 847                         if (user_mode( regs ) && (regs->uregs[14] & 0x01))
 848                         {
 849                                 regs->ARM_cpsr |= 0x20;
 850                         }
 851                 }
 852
 853                 //TODO: test - enter function, delete us retprobe, exit function
 854                 // for user space retprobes only - deferred deletion
 855
 856                 if (trampoline_address != (unsigned long) &kretprobe_trampoline)
 857                 {
 858                         // if we are not at the end of the list and current retprobe should be disarmed
 859                         if (node && ri->rp2)
 860                         {
 861                                 struct hlist_node *current_node = node;
 862                                 crp = ri->rp2;
 863                                 /*sprintf(die_msg, "deferred disarm p->addr = %p [%lx %lx %lx]\n",
 864                                   crp->kp.addr, *kaddrs[0], *kaddrs[1], *kaddrs[2]);
 865                                   DIE(die_msg, regs); */
 866                                 // look for other instances for the same retprobe
 867                                 hlist_for_each_entry_safe (ri, node, tmp, head, hlist)
 868                                 {
 869                                         /*
 870                                          * Trying to find another retprobe instance associated with
 871                                          * the same retprobe.
 872                                          */
 873                                         if (ri->rp2 == crp && node != current_node)
 874                                                 break;
 875                                 }
 876
 877                                 if (!node)
 878                                 {
 879                                         // if there are no more instances for this retprobe
 880                                         // delete retprobe
 881                                         struct kprobe *is_p = &crp->kp;
 882                                         DBPRINTF ("defered retprobe deletion p->addr = %p", crp->kp.addr);
 883                                         /*
 884                                           If there is no any retprobe instances of this retprobe
 885                                           we can free the resources related to the probe.
 886                                          */
 887                                         if (!(hlist_unhashed(&is_p->is_hlist_arm))) {
 888                                                 hlist_del_rcu(&is_p->is_hlist_arm);
 889                                         }
 890                                         if (!(hlist_unhashed(&is_p->is_hlist_thumb))) {
 891                                                 hlist_del_rcu(&is_p->is_hlist_thumb);
 892                                         }
 893
 894                                         dbi_unregister_kprobe(&crp->kp, current);
 895                                         kfree (crp);
 896                                 }
 897                                 hlist_del(current_node);
 898                         }
 899                 }
 900
 901                 if (kcb->kprobe_status == KPROBE_REENTER) {
 902                         restore_previous_kprobe(kcb);
 903                 } else {
 904                         reset_current_kprobe();
 905                 }
 906         }
 907
 908         spin_unlock_irqrestore (&kretprobe_lock, flags);
 909
 910         /*
 911          * By returning a non-zero value, we are telling
 912          * kprobe_handler() that we don't want the post_handler
 913          * to run (and have re-enabled preemption)
 914          */
 915
 916         return 1;
 917 }
 918
 919 void  __arch_prepare_kretprobe (struct kretprobe *rp, struct pt_regs *regs)
 920 {
 921         struct kretprobe_instance *ri;
 922
 923         DBPRINTF ("start\n");
 924         //TODO: test - remove retprobe after func entry but before its exit
 925         if ((ri = get_free_rp_inst (rp)) != NULL)
 926         {
 927                 ri->rp = rp;
 928                 ri->rp2 = NULL;
 929                 ri->task = current;
 930                 ri->ret_addr = (kprobe_opcode_t *) regs->uregs[14];
 931                 ri->sp = (kprobe_opcode_t *)regs->ARM_sp; //uregs[13];
 932
 933                 if (rp->kp.tgid)
 934                         if (!thumb_mode( regs ))
 935                                 regs->uregs[14] = (unsigned long) (rp->kp.ainsn.insn + UPROBES_TRAMP_RET_BREAK_IDX);
 936                         else
 937                                 regs->uregs[14] = (unsigned long) (rp->kp.ainsn.insn) + 0x1b;
 938
 939                 else    /* Replace the return addr with trampoline addr */
 940                         regs->uregs[14] = (unsigned long) &kretprobe_trampoline;
 941
 942 //              DBPRINTF ("ret addr set to %p->%lx\n", ri->ret_addr, regs->uregs[14]);
 943                 add_rp_inst (ri);
 944         }
 945         else {
 946                 DBPRINTF ("WARNING: missed retprobe %p\n", rp->kp.addr);
 947                 rp->nmissed++;
 948         }
 949 }
 950
 951
 952 int asm_init_module_dependencies(void)
 953 {
 954         //No module dependencies
 955         return 0;
 956 }
 957
 958 void swap_register_undef_hook(struct undef_hook *hook)
 959 {
 960         __swap_register_undef_hook(hook);
 961 }
 962 EXPORT_SYMBOL_GPL(swap_register_undef_hook);
 963
 964 void swap_unregister_undef_hook(struct undef_hook *hook)
 965 {
 966         __swap_unregister_undef_hook(hook);
 967 }
 968 EXPORT_SYMBOL_GPL(swap_unregister_undef_hook);
 969
 970 // kernel probes hook
 971 static struct undef_hook undef_ho_k = {
 972     .instr_mask = 0xffffffff,
 973     .instr_val  = BREAKPOINT_INSTRUCTION,
 974     .cpsr_mask  = MODE_MASK,
 975     .cpsr_val   = SVC_MODE,
 976     .fn         = kprobe_trap_handler
 977 };
 978
 979 int __init arch_init_kprobes (void)
 980 {
 981         unsigned int do_bp_handler = 0;
 982         int ret = 0;
 983
 984         if (arch_init_module_dependencies())
 985         {
 986                 DBPRINTF ("Unable to init module dependencies\n");
 987                 return -1;
 988         }
 989
 990         do_bp_handler = swap_ksyms("do_undefinstr");
 991         if (do_bp_handler == 0) {
 992                 DBPRINTF("no do_undefinstr symbol found!");
 993                 return -1;
 994         }
 995         arr_traps_template[NOTIFIER_CALL_CHAIN_INDEX] = arch_construct_brunch ((unsigned int)kprobe_handler, do_bp_handler + NOTIFIER_CALL_CHAIN_INDEX * 4, 1);
 996         // Register hooks (kprobe_handler)
 997         __swap_register_undef_hook = swap_ksyms("register_undef_hook");
 998         if (__swap_register_undef_hook == NULL) {
 999                 printk("no register_undef_hook symbol found!\n");
1000                 return -1;
1001         }
1002
1003         // Unregister hooks (kprobe_handler)
1004         __swap_unregister_undef_hook = swap_ksyms("unregister_undef_hook");
1005         if (__swap_unregister_undef_hook == NULL) {
1006                 printk("no unregister_undef_hook symbol found!\n");
1007                 return -1;
1008         }
1009
1010         swap_register_undef_hook(&undef_ho_k);
1011         if ((ret = dbi_register_kprobe (&trampoline_p)) != 0) {
1012                 //dbi_unregister_jprobe(&do_exit_p, 0);
1013                 return ret;
1014         }
1015         return ret;
1016 }
1017
1018 void __exit dbi_arch_exit_kprobes (void)
1019 {
1020         swap_unregister_undef_hook(&undef_ho_k);
1021 }
1022
1023 //EXPORT_SYMBOL_GPL (dbi_arch_uprobe_return);
1024 //EXPORT_SYMBOL_GPL (dbi_arch_exit_kprobes);