Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 1 | /* |
| 2 | * Kernel probes (kprobes) for SuperH |
| 3 | * |
| 4 | * Copyright (C) 2007 Chris Smith <chris.smith@st.com> |
| 5 | * Copyright (C) 2006 Lineo Solutions, Inc. |
| 6 | * |
| 7 | * This file is subject to the terms and conditions of the GNU General Public |
| 8 | * License. See the file "COPYING" in the main directory of this archive |
| 9 | * for more details. |
| 10 | */ |
| 11 | #include <linux/kprobes.h> |
| 12 | #include <linux/module.h> |
| 13 | #include <linux/ptrace.h> |
| 14 | #include <linux/preempt.h> |
| 15 | #include <linux/kdebug.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame^] | 16 | #include <linux/slab.h> |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 17 | #include <asm/cacheflush.h> |
| 18 | #include <asm/uaccess.h> |
| 19 | |
| 20 | DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; |
| 21 | DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); |
| 22 | |
| 23 | static struct kprobe saved_current_opcode; |
| 24 | static struct kprobe saved_next_opcode; |
| 25 | static struct kprobe saved_next_opcode2; |
| 26 | |
| 27 | #define OPCODE_JMP(x) (((x) & 0xF0FF) == 0x402b) |
| 28 | #define OPCODE_JSR(x) (((x) & 0xF0FF) == 0x400b) |
| 29 | #define OPCODE_BRA(x) (((x) & 0xF000) == 0xa000) |
| 30 | #define OPCODE_BRAF(x) (((x) & 0xF0FF) == 0x0023) |
| 31 | #define OPCODE_BSR(x) (((x) & 0xF000) == 0xb000) |
| 32 | #define OPCODE_BSRF(x) (((x) & 0xF0FF) == 0x0003) |
| 33 | |
| 34 | #define OPCODE_BF_S(x) (((x) & 0xFF00) == 0x8f00) |
| 35 | #define OPCODE_BT_S(x) (((x) & 0xFF00) == 0x8d00) |
| 36 | |
| 37 | #define OPCODE_BF(x) (((x) & 0xFF00) == 0x8b00) |
| 38 | #define OPCODE_BT(x) (((x) & 0xFF00) == 0x8900) |
| 39 | |
| 40 | #define OPCODE_RTS(x) (((x) & 0x000F) == 0x000b) |
| 41 | #define OPCODE_RTE(x) (((x) & 0xFFFF) == 0x002b) |
| 42 | |
| 43 | int __kprobes arch_prepare_kprobe(struct kprobe *p) |
| 44 | { |
| 45 | kprobe_opcode_t opcode = *(kprobe_opcode_t *) (p->addr); |
| 46 | |
| 47 | if (OPCODE_RTE(opcode)) |
| 48 | return -EFAULT; /* Bad breakpoint */ |
| 49 | |
| 50 | p->opcode = opcode; |
| 51 | |
| 52 | return 0; |
| 53 | } |
| 54 | |
| 55 | void __kprobes arch_copy_kprobe(struct kprobe *p) |
| 56 | { |
| 57 | memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t)); |
| 58 | p->opcode = *p->addr; |
| 59 | } |
| 60 | |
| 61 | void __kprobes arch_arm_kprobe(struct kprobe *p) |
| 62 | { |
| 63 | *p->addr = BREAKPOINT_INSTRUCTION; |
| 64 | flush_icache_range((unsigned long)p->addr, |
| 65 | (unsigned long)p->addr + sizeof(kprobe_opcode_t)); |
| 66 | } |
| 67 | |
| 68 | void __kprobes arch_disarm_kprobe(struct kprobe *p) |
| 69 | { |
| 70 | *p->addr = p->opcode; |
| 71 | flush_icache_range((unsigned long)p->addr, |
| 72 | (unsigned long)p->addr + sizeof(kprobe_opcode_t)); |
| 73 | } |
| 74 | |
| 75 | int __kprobes arch_trampoline_kprobe(struct kprobe *p) |
| 76 | { |
| 77 | if (*p->addr == BREAKPOINT_INSTRUCTION) |
| 78 | return 1; |
| 79 | |
| 80 | return 0; |
| 81 | } |
| 82 | |
| 83 | /** |
| 84 | * If an illegal slot instruction exception occurs for an address |
| 85 | * containing a kprobe, remove the probe. |
| 86 | * |
| 87 | * Returns 0 if the exception was handled successfully, 1 otherwise. |
| 88 | */ |
| 89 | int __kprobes kprobe_handle_illslot(unsigned long pc) |
| 90 | { |
| 91 | struct kprobe *p = get_kprobe((kprobe_opcode_t *) pc + 1); |
| 92 | |
| 93 | if (p != NULL) { |
| 94 | printk("Warning: removing kprobe from delay slot: 0x%.8x\n", |
| 95 | (unsigned int)pc + 2); |
| 96 | unregister_kprobe(p); |
| 97 | return 0; |
| 98 | } |
| 99 | |
| 100 | return 1; |
| 101 | } |
| 102 | |
| 103 | void __kprobes arch_remove_kprobe(struct kprobe *p) |
| 104 | { |
| 105 | if (saved_next_opcode.addr != 0x0) { |
| 106 | arch_disarm_kprobe(p); |
| 107 | arch_disarm_kprobe(&saved_next_opcode); |
| 108 | saved_next_opcode.addr = 0x0; |
| 109 | saved_next_opcode.opcode = 0x0; |
| 110 | |
| 111 | if (saved_next_opcode2.addr != 0x0) { |
| 112 | arch_disarm_kprobe(&saved_next_opcode2); |
| 113 | saved_next_opcode2.addr = 0x0; |
| 114 | saved_next_opcode2.opcode = 0x0; |
| 115 | } |
| 116 | } |
| 117 | } |
| 118 | |
Paul Mundt | 4eb5845 | 2008-09-08 18:22:47 +0900 | [diff] [blame] | 119 | static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb) |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 120 | { |
| 121 | kcb->prev_kprobe.kp = kprobe_running(); |
| 122 | kcb->prev_kprobe.status = kcb->kprobe_status; |
| 123 | } |
| 124 | |
Paul Mundt | 4eb5845 | 2008-09-08 18:22:47 +0900 | [diff] [blame] | 125 | static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb) |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 126 | { |
| 127 | __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp; |
| 128 | kcb->kprobe_status = kcb->prev_kprobe.status; |
| 129 | } |
| 130 | |
Paul Mundt | 4eb5845 | 2008-09-08 18:22:47 +0900 | [diff] [blame] | 131 | static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs, |
| 132 | struct kprobe_ctlblk *kcb) |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 133 | { |
| 134 | __get_cpu_var(current_kprobe) = p; |
| 135 | } |
| 136 | |
| 137 | /* |
| 138 | * Singlestep is implemented by disabling the current kprobe and setting one |
| 139 | * on the next instruction, following branches. Two probes are set if the |
| 140 | * branch is conditional. |
| 141 | */ |
Paul Mundt | 4eb5845 | 2008-09-08 18:22:47 +0900 | [diff] [blame] | 142 | static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 143 | { |
| 144 | kprobe_opcode_t *addr = NULL; |
| 145 | saved_current_opcode.addr = (kprobe_opcode_t *) (regs->pc); |
| 146 | addr = saved_current_opcode.addr; |
| 147 | |
| 148 | if (p != NULL) { |
| 149 | arch_disarm_kprobe(p); |
| 150 | |
| 151 | if (OPCODE_JSR(p->opcode) || OPCODE_JMP(p->opcode)) { |
| 152 | unsigned int reg_nr = ((p->opcode >> 8) & 0x000F); |
| 153 | saved_next_opcode.addr = |
| 154 | (kprobe_opcode_t *) regs->regs[reg_nr]; |
| 155 | } else if (OPCODE_BRA(p->opcode) || OPCODE_BSR(p->opcode)) { |
| 156 | unsigned long disp = (p->opcode & 0x0FFF); |
| 157 | saved_next_opcode.addr = |
| 158 | (kprobe_opcode_t *) (regs->pc + 4 + disp * 2); |
| 159 | |
| 160 | } else if (OPCODE_BRAF(p->opcode) || OPCODE_BSRF(p->opcode)) { |
| 161 | unsigned int reg_nr = ((p->opcode >> 8) & 0x000F); |
| 162 | saved_next_opcode.addr = |
| 163 | (kprobe_opcode_t *) (regs->pc + 4 + |
| 164 | regs->regs[reg_nr]); |
| 165 | |
| 166 | } else if (OPCODE_RTS(p->opcode)) { |
| 167 | saved_next_opcode.addr = (kprobe_opcode_t *) regs->pr; |
| 168 | |
| 169 | } else if (OPCODE_BF(p->opcode) || OPCODE_BT(p->opcode)) { |
| 170 | unsigned long disp = (p->opcode & 0x00FF); |
| 171 | /* case 1 */ |
| 172 | saved_next_opcode.addr = p->addr + 1; |
| 173 | /* case 2 */ |
| 174 | saved_next_opcode2.addr = |
| 175 | (kprobe_opcode_t *) (regs->pc + 4 + disp * 2); |
| 176 | saved_next_opcode2.opcode = *(saved_next_opcode2.addr); |
| 177 | arch_arm_kprobe(&saved_next_opcode2); |
| 178 | |
| 179 | } else if (OPCODE_BF_S(p->opcode) || OPCODE_BT_S(p->opcode)) { |
| 180 | unsigned long disp = (p->opcode & 0x00FF); |
| 181 | /* case 1 */ |
| 182 | saved_next_opcode.addr = p->addr + 2; |
| 183 | /* case 2 */ |
| 184 | saved_next_opcode2.addr = |
| 185 | (kprobe_opcode_t *) (regs->pc + 4 + disp * 2); |
| 186 | saved_next_opcode2.opcode = *(saved_next_opcode2.addr); |
| 187 | arch_arm_kprobe(&saved_next_opcode2); |
| 188 | |
| 189 | } else { |
| 190 | saved_next_opcode.addr = p->addr + 1; |
| 191 | } |
| 192 | |
| 193 | saved_next_opcode.opcode = *(saved_next_opcode.addr); |
| 194 | arch_arm_kprobe(&saved_next_opcode); |
| 195 | } |
| 196 | } |
| 197 | |
| 198 | /* Called with kretprobe_lock held */ |
| 199 | void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, |
| 200 | struct pt_regs *regs) |
| 201 | { |
| 202 | ri->ret_addr = (kprobe_opcode_t *) regs->pr; |
| 203 | |
| 204 | /* Replace the return addr with trampoline addr */ |
| 205 | regs->pr = (unsigned long)kretprobe_trampoline; |
| 206 | } |
| 207 | |
| 208 | static int __kprobes kprobe_handler(struct pt_regs *regs) |
| 209 | { |
| 210 | struct kprobe *p; |
| 211 | int ret = 0; |
| 212 | kprobe_opcode_t *addr = NULL; |
| 213 | struct kprobe_ctlblk *kcb; |
| 214 | |
| 215 | /* |
| 216 | * We don't want to be preempted for the entire |
| 217 | * duration of kprobe processing |
| 218 | */ |
| 219 | preempt_disable(); |
| 220 | kcb = get_kprobe_ctlblk(); |
| 221 | |
| 222 | addr = (kprobe_opcode_t *) (regs->pc); |
| 223 | |
| 224 | /* Check we're not actually recursing */ |
| 225 | if (kprobe_running()) { |
| 226 | p = get_kprobe(addr); |
| 227 | if (p) { |
| 228 | if (kcb->kprobe_status == KPROBE_HIT_SS && |
| 229 | *p->ainsn.insn == BREAKPOINT_INSTRUCTION) { |
| 230 | goto no_kprobe; |
| 231 | } |
| 232 | /* We have reentered the kprobe_handler(), since |
| 233 | * another probe was hit while within the handler. |
| 234 | * We here save the original kprobes variables and |
| 235 | * just single step on the instruction of the new probe |
| 236 | * without calling any user handlers. |
| 237 | */ |
| 238 | save_previous_kprobe(kcb); |
| 239 | set_current_kprobe(p, regs, kcb); |
| 240 | kprobes_inc_nmissed_count(p); |
| 241 | prepare_singlestep(p, regs); |
| 242 | kcb->kprobe_status = KPROBE_REENTER; |
| 243 | return 1; |
| 244 | } else { |
| 245 | p = __get_cpu_var(current_kprobe); |
| 246 | if (p->break_handler && p->break_handler(p, regs)) { |
| 247 | goto ss_probe; |
| 248 | } |
| 249 | } |
| 250 | goto no_kprobe; |
| 251 | } |
| 252 | |
| 253 | p = get_kprobe(addr); |
| 254 | if (!p) { |
| 255 | /* Not one of ours: let kernel handle it */ |
Paul Mundt | 734db37 | 2008-09-08 18:15:55 +0900 | [diff] [blame] | 256 | if (*(kprobe_opcode_t *)addr != BREAKPOINT_INSTRUCTION) { |
| 257 | /* |
| 258 | * The breakpoint instruction was removed right |
| 259 | * after we hit it. Another cpu has removed |
| 260 | * either a probepoint or a debugger breakpoint |
| 261 | * at this address. In either case, no further |
| 262 | * handling of this interrupt is appropriate. |
| 263 | */ |
| 264 | ret = 1; |
| 265 | } |
| 266 | |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 267 | goto no_kprobe; |
| 268 | } |
| 269 | |
| 270 | set_current_kprobe(p, regs, kcb); |
| 271 | kcb->kprobe_status = KPROBE_HIT_ACTIVE; |
| 272 | |
| 273 | if (p->pre_handler && p->pre_handler(p, regs)) |
| 274 | /* handler has already set things up, so skip ss setup */ |
| 275 | return 1; |
| 276 | |
Paul Mundt | 4eb5845 | 2008-09-08 18:22:47 +0900 | [diff] [blame] | 277 | ss_probe: |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 278 | prepare_singlestep(p, regs); |
| 279 | kcb->kprobe_status = KPROBE_HIT_SS; |
| 280 | return 1; |
| 281 | |
Paul Mundt | 4eb5845 | 2008-09-08 18:22:47 +0900 | [diff] [blame] | 282 | no_kprobe: |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 283 | preempt_enable_no_resched(); |
| 284 | return ret; |
| 285 | } |
| 286 | |
| 287 | /* |
| 288 | * For function-return probes, init_kprobes() establishes a probepoint |
| 289 | * here. When a retprobed function returns, this probe is hit and |
| 290 | * trampoline_probe_handler() runs, calling the kretprobe's handler. |
| 291 | */ |
Paul Mundt | e7cb016 | 2008-09-08 12:02:17 +0900 | [diff] [blame] | 292 | static void __used kretprobe_trampoline_holder(void) |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 293 | { |
Paul Mundt | 6eb2139 | 2008-09-09 08:13:28 +0900 | [diff] [blame] | 294 | asm volatile (".globl kretprobe_trampoline\n" |
| 295 | "kretprobe_trampoline:\n\t" |
| 296 | "nop\n"); |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 297 | } |
| 298 | |
| 299 | /* |
| 300 | * Called when we hit the probe point at kretprobe_trampoline |
| 301 | */ |
| 302 | int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) |
| 303 | { |
| 304 | struct kretprobe_instance *ri = NULL; |
| 305 | struct hlist_head *head, empty_rp; |
| 306 | struct hlist_node *node, *tmp; |
| 307 | unsigned long flags, orig_ret_address = 0; |
| 308 | unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline; |
| 309 | |
| 310 | INIT_HLIST_HEAD(&empty_rp); |
| 311 | kretprobe_hash_lock(current, &head, &flags); |
| 312 | |
| 313 | /* |
| 314 | * It is possible to have multiple instances associated with a given |
| 315 | * task either because an multiple functions in the call path |
| 316 | * have a return probe installed on them, and/or more then one return |
| 317 | * return probe was registered for a target function. |
| 318 | * |
| 319 | * We can handle this because: |
| 320 | * - instances are always inserted at the head of the list |
| 321 | * - when multiple return probes are registered for the same |
| 322 | * function, the first instance's ret_addr will point to the |
| 323 | * real return address, and all the rest will point to |
| 324 | * kretprobe_trampoline |
| 325 | */ |
| 326 | hlist_for_each_entry_safe(ri, node, tmp, head, hlist) { |
| 327 | if (ri->task != current) |
| 328 | /* another task is sharing our hash bucket */ |
| 329 | continue; |
| 330 | |
| 331 | if (ri->rp && ri->rp->handler) { |
| 332 | __get_cpu_var(current_kprobe) = &ri->rp->kp; |
| 333 | ri->rp->handler(ri, regs); |
| 334 | __get_cpu_var(current_kprobe) = NULL; |
| 335 | } |
| 336 | |
| 337 | orig_ret_address = (unsigned long)ri->ret_addr; |
| 338 | recycle_rp_inst(ri, &empty_rp); |
| 339 | |
| 340 | if (orig_ret_address != trampoline_address) |
| 341 | /* |
| 342 | * This is the real return address. Any other |
| 343 | * instances associated with this task are for |
| 344 | * other calls deeper on the call stack |
| 345 | */ |
| 346 | break; |
| 347 | } |
| 348 | |
| 349 | kretprobe_assert(ri, orig_ret_address, trampoline_address); |
| 350 | |
| 351 | regs->pc = orig_ret_address; |
| 352 | kretprobe_hash_unlock(current, &flags); |
| 353 | |
| 354 | preempt_enable_no_resched(); |
| 355 | |
| 356 | hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { |
| 357 | hlist_del(&ri->hlist); |
| 358 | kfree(ri); |
| 359 | } |
| 360 | |
| 361 | return orig_ret_address; |
| 362 | } |
| 363 | |
Paul Mundt | 4eb5845 | 2008-09-08 18:22:47 +0900 | [diff] [blame] | 364 | static int __kprobes post_kprobe_handler(struct pt_regs *regs) |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 365 | { |
| 366 | struct kprobe *cur = kprobe_running(); |
| 367 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); |
| 368 | kprobe_opcode_t *addr = NULL; |
| 369 | struct kprobe *p = NULL; |
| 370 | |
| 371 | if (!cur) |
| 372 | return 0; |
| 373 | |
| 374 | if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) { |
| 375 | kcb->kprobe_status = KPROBE_HIT_SSDONE; |
| 376 | cur->post_handler(cur, regs, 0); |
| 377 | } |
| 378 | |
| 379 | if (saved_next_opcode.addr != 0x0) { |
| 380 | arch_disarm_kprobe(&saved_next_opcode); |
| 381 | saved_next_opcode.addr = 0x0; |
| 382 | saved_next_opcode.opcode = 0x0; |
| 383 | |
| 384 | addr = saved_current_opcode.addr; |
| 385 | saved_current_opcode.addr = 0x0; |
| 386 | |
| 387 | p = get_kprobe(addr); |
| 388 | arch_arm_kprobe(p); |
| 389 | |
| 390 | if (saved_next_opcode2.addr != 0x0) { |
| 391 | arch_disarm_kprobe(&saved_next_opcode2); |
| 392 | saved_next_opcode2.addr = 0x0; |
| 393 | saved_next_opcode2.opcode = 0x0; |
| 394 | } |
| 395 | } |
| 396 | |
Paul Mundt | 4eb5845 | 2008-09-08 18:22:47 +0900 | [diff] [blame] | 397 | /* Restore back the original saved kprobes variables and continue. */ |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 398 | if (kcb->kprobe_status == KPROBE_REENTER) { |
| 399 | restore_previous_kprobe(kcb); |
| 400 | goto out; |
| 401 | } |
Paul Mundt | 4eb5845 | 2008-09-08 18:22:47 +0900 | [diff] [blame] | 402 | |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 403 | reset_current_kprobe(); |
| 404 | |
Paul Mundt | 4eb5845 | 2008-09-08 18:22:47 +0900 | [diff] [blame] | 405 | out: |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 406 | preempt_enable_no_resched(); |
| 407 | |
| 408 | return 1; |
| 409 | } |
| 410 | |
Paul Mundt | 037c10a | 2008-09-08 12:22:47 +0900 | [diff] [blame] | 411 | int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr) |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 412 | { |
| 413 | struct kprobe *cur = kprobe_running(); |
| 414 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); |
| 415 | const struct exception_table_entry *entry; |
| 416 | |
| 417 | switch (kcb->kprobe_status) { |
| 418 | case KPROBE_HIT_SS: |
| 419 | case KPROBE_REENTER: |
| 420 | /* |
| 421 | * We are here because the instruction being single |
| 422 | * stepped caused a page fault. We reset the current |
| 423 | * kprobe, point the pc back to the probe address |
| 424 | * and allow the page fault handler to continue as a |
| 425 | * normal page fault. |
| 426 | */ |
| 427 | regs->pc = (unsigned long)cur->addr; |
| 428 | if (kcb->kprobe_status == KPROBE_REENTER) |
| 429 | restore_previous_kprobe(kcb); |
| 430 | else |
| 431 | reset_current_kprobe(); |
| 432 | preempt_enable_no_resched(); |
| 433 | break; |
| 434 | case KPROBE_HIT_ACTIVE: |
| 435 | case KPROBE_HIT_SSDONE: |
| 436 | /* |
| 437 | * We increment the nmissed count for accounting, |
| 438 | * we can also use npre/npostfault count for accounting |
| 439 | * these specific fault cases. |
| 440 | */ |
| 441 | kprobes_inc_nmissed_count(cur); |
| 442 | |
| 443 | /* |
| 444 | * We come here because instructions in the pre/post |
| 445 | * handler caused the page_fault, this could happen |
| 446 | * if handler tries to access user space by |
| 447 | * copy_from_user(), get_user() etc. Let the |
| 448 | * user-specified handler try to fix it first. |
| 449 | */ |
| 450 | if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr)) |
| 451 | return 1; |
| 452 | |
| 453 | /* |
| 454 | * In case the user-specified fault handler returned |
| 455 | * zero, try to fix up. |
| 456 | */ |
| 457 | if ((entry = search_exception_tables(regs->pc)) != NULL) { |
| 458 | regs->pc = entry->fixup; |
| 459 | return 1; |
| 460 | } |
| 461 | |
| 462 | /* |
| 463 | * fixup_exception() could not handle it, |
| 464 | * Let do_page_fault() fix it. |
| 465 | */ |
| 466 | break; |
| 467 | default: |
| 468 | break; |
| 469 | } |
Paul Mundt | 4eb5845 | 2008-09-08 18:22:47 +0900 | [diff] [blame] | 470 | |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 471 | return 0; |
| 472 | } |
| 473 | |
| 474 | /* |
| 475 | * Wrapper routine to for handling exceptions. |
| 476 | */ |
| 477 | int __kprobes kprobe_exceptions_notify(struct notifier_block *self, |
| 478 | unsigned long val, void *data) |
| 479 | { |
| 480 | struct kprobe *p = NULL; |
| 481 | struct die_args *args = (struct die_args *)data; |
| 482 | int ret = NOTIFY_DONE; |
| 483 | kprobe_opcode_t *addr = NULL; |
| 484 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); |
| 485 | |
| 486 | addr = (kprobe_opcode_t *) (args->regs->pc); |
| 487 | if (val == DIE_TRAP) { |
| 488 | if (!kprobe_running()) { |
| 489 | if (kprobe_handler(args->regs)) { |
| 490 | ret = NOTIFY_STOP; |
| 491 | } else { |
| 492 | /* Not a kprobe trap */ |
Paul Mundt | ee386de | 2008-09-08 18:12:33 +0900 | [diff] [blame] | 493 | ret = NOTIFY_DONE; |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 494 | } |
| 495 | } else { |
| 496 | p = get_kprobe(addr); |
| 497 | if ((kcb->kprobe_status == KPROBE_HIT_SS) || |
| 498 | (kcb->kprobe_status == KPROBE_REENTER)) { |
| 499 | if (post_kprobe_handler(args->regs)) |
| 500 | ret = NOTIFY_STOP; |
| 501 | } else { |
| 502 | if (kprobe_handler(args->regs)) { |
| 503 | ret = NOTIFY_STOP; |
| 504 | } else { |
| 505 | p = __get_cpu_var(current_kprobe); |
Paul Mundt | 4eb5845 | 2008-09-08 18:22:47 +0900 | [diff] [blame] | 506 | if (p->break_handler && |
| 507 | p->break_handler(p, args->regs)) |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 508 | ret = NOTIFY_STOP; |
| 509 | } |
| 510 | } |
| 511 | } |
| 512 | } |
| 513 | |
| 514 | return ret; |
| 515 | } |
| 516 | |
| 517 | int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) |
| 518 | { |
| 519 | struct jprobe *jp = container_of(p, struct jprobe, kp); |
| 520 | unsigned long addr; |
| 521 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); |
| 522 | |
| 523 | kcb->jprobe_saved_regs = *regs; |
| 524 | kcb->jprobe_saved_r15 = regs->regs[15]; |
| 525 | addr = kcb->jprobe_saved_r15; |
| 526 | |
| 527 | /* |
| 528 | * TBD: As Linus pointed out, gcc assumes that the callee |
| 529 | * owns the argument space and could overwrite it, e.g. |
| 530 | * tailcall optimization. So, to be absolutely safe |
| 531 | * we also save and restore enough stack bytes to cover |
| 532 | * the argument area. |
| 533 | */ |
| 534 | memcpy(kcb->jprobes_stack, (kprobe_opcode_t *) addr, |
| 535 | MIN_STACK_SIZE(addr)); |
| 536 | |
| 537 | regs->pc = (unsigned long)(jp->entry); |
| 538 | |
| 539 | return 1; |
| 540 | } |
| 541 | |
| 542 | void __kprobes jprobe_return(void) |
| 543 | { |
Paul Mundt | 174b5c9 | 2008-09-08 18:10:10 +0900 | [diff] [blame] | 544 | asm volatile ("trapa #0x3a\n\t" "jprobe_return_end:\n\t" "nop\n\t"); |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 545 | } |
| 546 | |
| 547 | int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) |
| 548 | { |
| 549 | struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 550 | unsigned long stack_addr = kcb->jprobe_saved_r15; |
Paul Mundt | 4eb5845 | 2008-09-08 18:22:47 +0900 | [diff] [blame] | 551 | u8 *addr = (u8 *)regs->pc; |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 552 | |
Paul Mundt | 4eb5845 | 2008-09-08 18:22:47 +0900 | [diff] [blame] | 553 | if ((addr >= (u8 *)jprobe_return) && |
| 554 | (addr <= (u8 *)jprobe_return_end)) { |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 555 | *regs = kcb->jprobe_saved_regs; |
| 556 | |
Paul Mundt | 4eb5845 | 2008-09-08 18:22:47 +0900 | [diff] [blame] | 557 | memcpy((kprobe_opcode_t *)stack_addr, kcb->jprobes_stack, |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 558 | MIN_STACK_SIZE(stack_addr)); |
| 559 | |
| 560 | kcb->kprobe_status = KPROBE_HIT_SS; |
Paul Mundt | 247bc6d | 2008-09-08 18:14:50 +0900 | [diff] [blame] | 561 | preempt_enable_no_resched(); |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 562 | return 1; |
| 563 | } |
Paul Mundt | 4eb5845 | 2008-09-08 18:22:47 +0900 | [diff] [blame] | 564 | |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 565 | return 0; |
| 566 | } |
| 567 | |
| 568 | static struct kprobe trampoline_p = { |
Paul Mundt | 4eb5845 | 2008-09-08 18:22:47 +0900 | [diff] [blame] | 569 | .addr = (kprobe_opcode_t *)&kretprobe_trampoline, |
Chris Smith | d39f545 | 2008-09-05 17:15:39 +0900 | [diff] [blame] | 570 | .pre_handler = trampoline_probe_handler |
| 571 | }; |
| 572 | |
| 573 | int __init arch_init_kprobes(void) |
| 574 | { |
| 575 | saved_next_opcode.addr = 0x0; |
| 576 | saved_next_opcode.opcode = 0x0; |
| 577 | |
| 578 | saved_current_opcode.addr = 0x0; |
| 579 | saved_current_opcode.opcode = 0x0; |
| 580 | |
| 581 | saved_next_opcode2.addr = 0x0; |
| 582 | saved_next_opcode2.opcode = 0x0; |
| 583 | |
| 584 | return register_kprobe(&trampoline_p); |
| 585 | } |