David Howells | b920de1 | 2008-02-08 04:19:31 -0800 | [diff] [blame] | 1 | /* MN10300 Kernel probes implementation |
| 2 | * |
| 3 | * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved. |
| 4 | * Written by Mark Salter (msalter@redhat.com) |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public Licence as published by |
| 8 | * the Free Software Foundation; either version 2 of the Licence, or |
| 9 | * (at your option) any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public Licence for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU General Public Licence |
| 17 | * along with this program; if not, write to the Free Software |
| 18 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 19 | */ |
| 20 | #include <linux/kprobes.h> |
| 21 | #include <linux/ptrace.h> |
| 22 | #include <linux/spinlock.h> |
| 23 | #include <linux/preempt.h> |
| 24 | #include <linux/kdebug.h> |
| 25 | #include <asm/cacheflush.h> |
| 26 | |
| 27 | struct kretprobe_blackpoint kretprobe_blacklist[] = { { NULL, NULL } }; |
| 28 | const int kretprobe_blacklist_size = ARRAY_SIZE(kretprobe_blacklist); |
| 29 | |
| 30 | /* kprobe_status settings */ |
| 31 | #define KPROBE_HIT_ACTIVE 0x00000001 |
| 32 | #define KPROBE_HIT_SS 0x00000002 |
| 33 | |
| 34 | static struct kprobe *current_kprobe; |
| 35 | static unsigned long current_kprobe_orig_pc; |
| 36 | static unsigned long current_kprobe_next_pc; |
| 37 | static int current_kprobe_ss_flags; |
| 38 | static unsigned long kprobe_status; |
| 39 | static kprobe_opcode_t current_kprobe_ss_buf[MAX_INSN_SIZE + 2]; |
| 40 | static unsigned long current_kprobe_bp_addr; |
| 41 | |
| 42 | DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; |
| 43 | |
| 44 | |
| 45 | /* singlestep flag bits */ |
| 46 | #define SINGLESTEP_BRANCH 1 |
| 47 | #define SINGLESTEP_PCREL 2 |
| 48 | |
| 49 | #define READ_BYTE(p, valp) \ |
| 50 | do { *(u8 *)(valp) = *(u8 *)(p); } while (0) |
| 51 | |
| 52 | #define READ_WORD16(p, valp) \ |
| 53 | do { \ |
| 54 | READ_BYTE((p), (valp)); \ |
| 55 | READ_BYTE((u8 *)(p) + 1, (u8 *)(valp) + 1); \ |
| 56 | } while (0) |
| 57 | |
| 58 | #define READ_WORD32(p, valp) \ |
| 59 | do { \ |
| 60 | READ_BYTE((p), (valp)); \ |
| 61 | READ_BYTE((u8 *)(p) + 1, (u8 *)(valp) + 1); \ |
| 62 | READ_BYTE((u8 *)(p) + 2, (u8 *)(valp) + 2); \ |
| 63 | READ_BYTE((u8 *)(p) + 3, (u8 *)(valp) + 3); \ |
| 64 | } while (0) |
| 65 | |
| 66 | |
| 67 | static const u8 mn10300_insn_sizes[256] = |
| 68 | { |
| 69 | /* 1 2 3 4 5 6 7 8 9 a b c d e f */ |
| 70 | 1, 3, 3, 3, 1, 3, 3, 3, 1, 3, 3, 3, 1, 3, 3, 3, /* 0 */ |
| 71 | 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 1 */ |
| 72 | 2, 2, 2, 2, 3, 3, 3, 3, 2, 2, 2, 2, 3, 3, 3, 3, /* 2 */ |
| 73 | 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 1, 1, 1, /* 3 */ |
| 74 | 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, /* 4 */ |
| 75 | 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, /* 5 */ |
| 76 | 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 6 */ |
| 77 | 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 7 */ |
| 78 | 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* 8 */ |
| 79 | 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* 9 */ |
| 80 | 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* a */ |
| 81 | 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* b */ |
| 82 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 2, 2, /* c */ |
| 83 | 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* d */ |
| 84 | 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* e */ |
| 85 | 0, 2, 2, 2, 2, 2, 2, 4, 0, 3, 0, 4, 0, 6, 7, 1 /* f */ |
| 86 | }; |
| 87 | |
| 88 | #define LT (1 << 0) |
| 89 | #define GT (1 << 1) |
| 90 | #define GE (1 << 2) |
| 91 | #define LE (1 << 3) |
| 92 | #define CS (1 << 4) |
| 93 | #define HI (1 << 5) |
| 94 | #define CC (1 << 6) |
| 95 | #define LS (1 << 7) |
| 96 | #define EQ (1 << 8) |
| 97 | #define NE (1 << 9) |
| 98 | #define RA (1 << 10) |
| 99 | #define VC (1 << 11) |
| 100 | #define VS (1 << 12) |
| 101 | #define NC (1 << 13) |
| 102 | #define NS (1 << 14) |
| 103 | |
| 104 | static const u16 cond_table[] = { |
| 105 | /* V C N Z */ |
| 106 | /* 0 0 0 0 */ (NE | NC | CC | VC | GE | GT | HI), |
| 107 | /* 0 0 0 1 */ (EQ | NC | CC | VC | GE | LE | LS), |
| 108 | /* 0 0 1 0 */ (NE | NS | CC | VC | LT | LE | HI), |
| 109 | /* 0 0 1 1 */ (EQ | NS | CC | VC | LT | LE | LS), |
| 110 | /* 0 1 0 0 */ (NE | NC | CS | VC | GE | GT | LS), |
| 111 | /* 0 1 0 1 */ (EQ | NC | CS | VC | GE | LE | LS), |
| 112 | /* 0 1 1 0 */ (NE | NS | CS | VC | LT | LE | LS), |
| 113 | /* 0 1 1 1 */ (EQ | NS | CS | VC | LT | LE | LS), |
| 114 | /* 1 0 0 0 */ (NE | NC | CC | VS | LT | LE | HI), |
| 115 | /* 1 0 0 1 */ (EQ | NC | CC | VS | LT | LE | LS), |
| 116 | /* 1 0 1 0 */ (NE | NS | CC | VS | GE | GT | HI), |
| 117 | /* 1 0 1 1 */ (EQ | NS | CC | VS | GE | LE | LS), |
| 118 | /* 1 1 0 0 */ (NE | NC | CS | VS | LT | LE | LS), |
| 119 | /* 1 1 0 1 */ (EQ | NC | CS | VS | LT | LE | LS), |
| 120 | /* 1 1 1 0 */ (NE | NS | CS | VS | GE | GT | LS), |
| 121 | /* 1 1 1 1 */ (EQ | NS | CS | VS | GE | LE | LS), |
| 122 | }; |
| 123 | |
| 124 | /* |
| 125 | * Calculate what the PC will be after executing next instruction |
| 126 | */ |
| 127 | static unsigned find_nextpc(struct pt_regs *regs, int *flags) |
| 128 | { |
| 129 | unsigned size; |
| 130 | s8 x8; |
| 131 | s16 x16; |
| 132 | s32 x32; |
| 133 | u8 opc, *pc, *sp, *next; |
| 134 | |
| 135 | next = 0; |
| 136 | *flags = SINGLESTEP_PCREL; |
| 137 | |
| 138 | pc = (u8 *) regs->pc; |
| 139 | sp = (u8 *) (regs + 1); |
| 140 | opc = *pc; |
| 141 | |
| 142 | size = mn10300_insn_sizes[opc]; |
| 143 | if (size > 0) { |
| 144 | next = pc + size; |
| 145 | } else { |
| 146 | switch (opc) { |
| 147 | /* Bxx (d8,PC) */ |
| 148 | case 0xc0 ... 0xca: |
| 149 | x8 = 2; |
| 150 | if (cond_table[regs->epsw & 0xf] & (1 << (opc & 0xf))) |
| 151 | x8 = (s8)pc[1]; |
| 152 | next = pc + x8; |
| 153 | *flags |= SINGLESTEP_BRANCH; |
| 154 | break; |
| 155 | |
| 156 | /* JMP (d16,PC) or CALL (d16,PC) */ |
| 157 | case 0xcc: |
| 158 | case 0xcd: |
| 159 | READ_WORD16(pc + 1, &x16); |
| 160 | next = pc + x16; |
| 161 | *flags |= SINGLESTEP_BRANCH; |
| 162 | break; |
| 163 | |
| 164 | /* JMP (d32,PC) or CALL (d32,PC) */ |
| 165 | case 0xdc: |
| 166 | case 0xdd: |
| 167 | READ_WORD32(pc + 1, &x32); |
| 168 | next = pc + x32; |
| 169 | *flags |= SINGLESTEP_BRANCH; |
| 170 | break; |
| 171 | |
| 172 | /* RETF */ |
| 173 | case 0xde: |
| 174 | next = (u8 *)regs->mdr; |
| 175 | *flags &= ~SINGLESTEP_PCREL; |
| 176 | *flags |= SINGLESTEP_BRANCH; |
| 177 | break; |
| 178 | |
| 179 | /* RET */ |
| 180 | case 0xdf: |
| 181 | sp += pc[2]; |
| 182 | READ_WORD32(sp, &x32); |
| 183 | next = (u8 *)x32; |
| 184 | *flags &= ~SINGLESTEP_PCREL; |
| 185 | *flags |= SINGLESTEP_BRANCH; |
| 186 | break; |
| 187 | |
| 188 | case 0xf0: |
| 189 | next = pc + 2; |
| 190 | opc = pc[1]; |
| 191 | if (opc >= 0xf0 && opc <= 0xf7) { |
| 192 | /* JMP (An) / CALLS (An) */ |
| 193 | switch (opc & 3) { |
| 194 | case 0: |
| 195 | next = (u8 *)regs->a0; |
| 196 | break; |
| 197 | case 1: |
| 198 | next = (u8 *)regs->a1; |
| 199 | break; |
| 200 | case 2: |
| 201 | next = (u8 *)regs->a2; |
| 202 | break; |
| 203 | case 3: |
| 204 | next = (u8 *)regs->a3; |
| 205 | break; |
| 206 | } |
| 207 | *flags &= ~SINGLESTEP_PCREL; |
| 208 | *flags |= SINGLESTEP_BRANCH; |
| 209 | } else if (opc == 0xfc) { |
| 210 | /* RETS */ |
| 211 | READ_WORD32(sp, &x32); |
| 212 | next = (u8 *)x32; |
| 213 | *flags &= ~SINGLESTEP_PCREL; |
| 214 | *flags |= SINGLESTEP_BRANCH; |
| 215 | } else if (opc == 0xfd) { |
| 216 | /* RTI */ |
| 217 | READ_WORD32(sp + 4, &x32); |
| 218 | next = (u8 *)x32; |
| 219 | *flags &= ~SINGLESTEP_PCREL; |
| 220 | *flags |= SINGLESTEP_BRANCH; |
| 221 | } |
| 222 | break; |
| 223 | |
| 224 | /* potential 3-byte conditional branches */ |
| 225 | case 0xf8: |
| 226 | next = pc + 3; |
| 227 | opc = pc[1]; |
| 228 | if (opc >= 0xe8 && opc <= 0xeb && |
| 229 | (cond_table[regs->epsw & 0xf] & |
| 230 | (1 << ((opc & 0xf) + 3))) |
| 231 | ) { |
| 232 | READ_BYTE(pc+2, &x8); |
| 233 | next = pc + x8; |
| 234 | *flags |= SINGLESTEP_BRANCH; |
| 235 | } |
| 236 | break; |
| 237 | |
| 238 | case 0xfa: |
| 239 | if (pc[1] == 0xff) { |
| 240 | /* CALLS (d16,PC) */ |
| 241 | READ_WORD16(pc + 2, &x16); |
| 242 | next = pc + x16; |
| 243 | } else |
| 244 | next = pc + 4; |
| 245 | *flags |= SINGLESTEP_BRANCH; |
| 246 | break; |
| 247 | |
| 248 | case 0xfc: |
| 249 | x32 = 6; |
| 250 | if (pc[1] == 0xff) { |
| 251 | /* CALLS (d32,PC) */ |
| 252 | READ_WORD32(pc + 2, &x32); |
| 253 | } |
| 254 | next = pc + x32; |
| 255 | *flags |= SINGLESTEP_BRANCH; |
| 256 | break; |
| 257 | /* LXX (d8,PC) */ |
| 258 | /* SETLB - loads the next four bytes into the LIR reg */ |
| 259 | case 0xd0 ... 0xda: |
| 260 | case 0xdb: |
| 261 | panic("Can't singlestep Lxx/SETLB\n"); |
| 262 | break; |
| 263 | } |
| 264 | } |
| 265 | return (unsigned)next; |
| 266 | |
| 267 | } |
| 268 | |
| 269 | /* |
| 270 | * set up out of place singlestep of some branching instructions |
| 271 | */ |
| 272 | static unsigned __kprobes singlestep_branch_setup(struct pt_regs *regs) |
| 273 | { |
| 274 | u8 opc, *pc, *sp, *next; |
| 275 | |
| 276 | next = NULL; |
| 277 | pc = (u8 *) regs->pc; |
| 278 | sp = (u8 *) (regs + 1); |
| 279 | |
| 280 | switch (pc[0]) { |
| 281 | case 0xc0 ... 0xca: /* Bxx (d8,PC) */ |
| 282 | case 0xcc: /* JMP (d16,PC) */ |
| 283 | case 0xdc: /* JMP (d32,PC) */ |
| 284 | case 0xf8: /* Bxx (d8,PC) 3-byte version */ |
| 285 | /* don't really need to do anything except cause trap */ |
| 286 | next = pc; |
| 287 | break; |
| 288 | |
| 289 | case 0xcd: /* CALL (d16,PC) */ |
| 290 | pc[1] = 5; |
| 291 | pc[2] = 0; |
| 292 | next = pc + 5; |
| 293 | break; |
| 294 | |
| 295 | case 0xdd: /* CALL (d32,PC) */ |
| 296 | pc[1] = 7; |
| 297 | pc[2] = 0; |
| 298 | pc[3] = 0; |
| 299 | pc[4] = 0; |
| 300 | next = pc + 7; |
| 301 | break; |
| 302 | |
| 303 | case 0xde: /* RETF */ |
| 304 | next = pc + 3; |
| 305 | regs->mdr = (unsigned) next; |
| 306 | break; |
| 307 | |
| 308 | case 0xdf: /* RET */ |
| 309 | sp += pc[2]; |
| 310 | next = pc + 3; |
| 311 | *(unsigned *)sp = (unsigned) next; |
| 312 | break; |
| 313 | |
| 314 | case 0xf0: |
| 315 | next = pc + 2; |
| 316 | opc = pc[1]; |
| 317 | if (opc >= 0xf0 && opc <= 0xf3) { |
| 318 | /* CALLS (An) */ |
| 319 | /* use CALLS (d16,PC) to avoid mucking with An */ |
| 320 | pc[0] = 0xfa; |
| 321 | pc[1] = 0xff; |
| 322 | pc[2] = 4; |
| 323 | pc[3] = 0; |
| 324 | next = pc + 4; |
| 325 | } else if (opc >= 0xf4 && opc <= 0xf7) { |
| 326 | /* JMP (An) */ |
| 327 | next = pc; |
| 328 | } else if (opc == 0xfc) { |
| 329 | /* RETS */ |
| 330 | next = pc + 2; |
| 331 | *(unsigned *) sp = (unsigned) next; |
| 332 | } else if (opc == 0xfd) { |
| 333 | /* RTI */ |
| 334 | next = pc + 2; |
| 335 | *(unsigned *)(sp + 4) = (unsigned) next; |
| 336 | } |
| 337 | break; |
| 338 | |
| 339 | case 0xfa: /* CALLS (d16,PC) */ |
| 340 | pc[2] = 4; |
| 341 | pc[3] = 0; |
| 342 | next = pc + 4; |
| 343 | break; |
| 344 | |
| 345 | case 0xfc: /* CALLS (d32,PC) */ |
| 346 | pc[2] = 6; |
| 347 | pc[3] = 0; |
| 348 | pc[4] = 0; |
| 349 | pc[5] = 0; |
| 350 | next = pc + 6; |
| 351 | break; |
| 352 | |
| 353 | case 0xd0 ... 0xda: /* LXX (d8,PC) */ |
| 354 | case 0xdb: /* SETLB */ |
| 355 | panic("Can't singlestep Lxx/SETLB\n"); |
| 356 | } |
| 357 | |
| 358 | return (unsigned) next; |
| 359 | } |
| 360 | |
| 361 | int __kprobes arch_prepare_kprobe(struct kprobe *p) |
| 362 | { |
| 363 | return 0; |
| 364 | } |
| 365 | |
| 366 | void __kprobes arch_copy_kprobe(struct kprobe *p) |
| 367 | { |
| 368 | memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE); |
| 369 | } |
| 370 | |
| 371 | void __kprobes arch_arm_kprobe(struct kprobe *p) |
| 372 | { |
| 373 | *p->addr = BREAKPOINT_INSTRUCTION; |
| 374 | flush_icache_range((unsigned long) p->addr, |
| 375 | (unsigned long) p->addr + sizeof(kprobe_opcode_t)); |
| 376 | } |
| 377 | |
| 378 | void __kprobes arch_disarm_kprobe(struct kprobe *p) |
| 379 | { |
| 380 | mn10300_dcache_flush(); |
| 381 | mn10300_icache_inv(); |
| 382 | } |
| 383 | |
| 384 | void arch_remove_kprobe(struct kprobe *p) |
| 385 | { |
| 386 | } |
| 387 | |
| 388 | static inline |
| 389 | void __kprobes disarm_kprobe(struct kprobe *p, struct pt_regs *regs) |
| 390 | { |
| 391 | *p->addr = p->opcode; |
| 392 | regs->pc = (unsigned long) p->addr; |
| 393 | mn10300_dcache_flush(); |
| 394 | mn10300_icache_inv(); |
| 395 | } |
| 396 | |
| 397 | static inline |
| 398 | void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs) |
| 399 | { |
| 400 | unsigned long nextpc; |
| 401 | |
| 402 | current_kprobe_orig_pc = regs->pc; |
| 403 | memcpy(current_kprobe_ss_buf, &p->ainsn.insn[0], MAX_INSN_SIZE); |
| 404 | regs->pc = (unsigned long) current_kprobe_ss_buf; |
| 405 | |
| 406 | nextpc = find_nextpc(regs, ¤t_kprobe_ss_flags); |
| 407 | if (current_kprobe_ss_flags & SINGLESTEP_PCREL) |
| 408 | current_kprobe_next_pc = |
| 409 | current_kprobe_orig_pc + (nextpc - regs->pc); |
| 410 | else |
| 411 | current_kprobe_next_pc = nextpc; |
| 412 | |
| 413 | /* branching instructions need special handling */ |
| 414 | if (current_kprobe_ss_flags & SINGLESTEP_BRANCH) |
| 415 | nextpc = singlestep_branch_setup(regs); |
| 416 | |
| 417 | current_kprobe_bp_addr = nextpc; |
| 418 | |
| 419 | *(u8 *) nextpc = BREAKPOINT_INSTRUCTION; |
| 420 | mn10300_dcache_flush_range2((unsigned) current_kprobe_ss_buf, |
| 421 | sizeof(current_kprobe_ss_buf)); |
| 422 | mn10300_icache_inv(); |
| 423 | } |
| 424 | |
| 425 | static inline int __kprobes kprobe_handler(struct pt_regs *regs) |
| 426 | { |
| 427 | struct kprobe *p; |
| 428 | int ret = 0; |
| 429 | unsigned int *addr = (unsigned int *) regs->pc; |
| 430 | |
| 431 | /* We're in an interrupt, but this is clear and BUG()-safe. */ |
| 432 | preempt_disable(); |
| 433 | |
| 434 | /* Check we're not actually recursing */ |
| 435 | if (kprobe_running()) { |
| 436 | /* We *are* holding lock here, so this is safe. |
| 437 | Disarm the probe we just hit, and ignore it. */ |
| 438 | p = get_kprobe(addr); |
| 439 | if (p) { |
| 440 | disarm_kprobe(p, regs); |
| 441 | ret = 1; |
| 442 | } else { |
| 443 | p = current_kprobe; |
| 444 | if (p->break_handler && p->break_handler(p, regs)) |
| 445 | goto ss_probe; |
| 446 | } |
| 447 | /* If it's not ours, can't be delete race, (we hold lock). */ |
| 448 | goto no_kprobe; |
| 449 | } |
| 450 | |
| 451 | p = get_kprobe(addr); |
| 452 | if (!p) { |
| 453 | if (*addr != BREAKPOINT_INSTRUCTION) { |
| 454 | /* The breakpoint instruction was removed right after |
| 455 | * we hit it. Another cpu has removed either a |
| 456 | * probepoint or a debugger breakpoint at this address. |
| 457 | * In either case, no further handling of this |
| 458 | * interrupt is appropriate. |
| 459 | */ |
| 460 | ret = 1; |
| 461 | } |
| 462 | /* Not one of ours: let kernel handle it */ |
| 463 | goto no_kprobe; |
| 464 | } |
| 465 | |
| 466 | kprobe_status = KPROBE_HIT_ACTIVE; |
| 467 | current_kprobe = p; |
| 468 | if (p->pre_handler(p, regs)) { |
| 469 | /* handler has already set things up, so skip ss setup */ |
| 470 | return 1; |
| 471 | } |
| 472 | |
| 473 | ss_probe: |
| 474 | prepare_singlestep(p, regs); |
| 475 | kprobe_status = KPROBE_HIT_SS; |
| 476 | return 1; |
| 477 | |
| 478 | no_kprobe: |
| 479 | preempt_enable_no_resched(); |
| 480 | return ret; |
| 481 | } |
| 482 | |
| 483 | /* |
| 484 | * Called after single-stepping. p->addr is the address of the |
| 485 | * instruction whose first byte has been replaced by the "breakpoint" |
| 486 | * instruction. To avoid the SMP problems that can occur when we |
| 487 | * temporarily put back the original opcode to single-step, we |
| 488 | * single-stepped a copy of the instruction. The address of this |
| 489 | * copy is p->ainsn.insn. |
| 490 | */ |
| 491 | static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs) |
| 492 | { |
| 493 | /* we may need to fixup regs/stack after singlestepping a call insn */ |
| 494 | if (current_kprobe_ss_flags & SINGLESTEP_BRANCH) { |
| 495 | regs->pc = current_kprobe_orig_pc; |
| 496 | switch (p->ainsn.insn[0]) { |
| 497 | case 0xcd: /* CALL (d16,PC) */ |
| 498 | *(unsigned *) regs->sp = regs->mdr = regs->pc + 5; |
| 499 | break; |
| 500 | case 0xdd: /* CALL (d32,PC) */ |
| 501 | /* fixup mdr and return address on stack */ |
| 502 | *(unsigned *) regs->sp = regs->mdr = regs->pc + 7; |
| 503 | break; |
| 504 | case 0xf0: |
| 505 | if (p->ainsn.insn[1] >= 0xf0 && |
| 506 | p->ainsn.insn[1] <= 0xf3) { |
| 507 | /* CALLS (An) */ |
| 508 | /* fixup MDR and return address on stack */ |
| 509 | regs->mdr = regs->pc + 2; |
| 510 | *(unsigned *) regs->sp = regs->mdr; |
| 511 | } |
| 512 | break; |
| 513 | |
| 514 | case 0xfa: /* CALLS (d16,PC) */ |
| 515 | /* fixup MDR and return address on stack */ |
| 516 | *(unsigned *) regs->sp = regs->mdr = regs->pc + 4; |
| 517 | break; |
| 518 | |
| 519 | case 0xfc: /* CALLS (d32,PC) */ |
| 520 | /* fixup MDR and return address on stack */ |
| 521 | *(unsigned *) regs->sp = regs->mdr = regs->pc + 6; |
| 522 | break; |
| 523 | } |
| 524 | } |
| 525 | |
| 526 | regs->pc = current_kprobe_next_pc; |
| 527 | current_kprobe_bp_addr = 0; |
| 528 | } |
| 529 | |
| 530 | static inline int __kprobes post_kprobe_handler(struct pt_regs *regs) |
| 531 | { |
| 532 | if (!kprobe_running()) |
| 533 | return 0; |
| 534 | |
| 535 | if (current_kprobe->post_handler) |
| 536 | current_kprobe->post_handler(current_kprobe, regs, 0); |
| 537 | |
| 538 | resume_execution(current_kprobe, regs); |
| 539 | reset_current_kprobe(); |
| 540 | preempt_enable_no_resched(); |
| 541 | return 1; |
| 542 | } |
| 543 | |
| 544 | /* Interrupts disabled, kprobe_lock held. */ |
| 545 | static inline |
| 546 | int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr) |
| 547 | { |
| 548 | if (current_kprobe->fault_handler && |
| 549 | current_kprobe->fault_handler(current_kprobe, regs, trapnr)) |
| 550 | return 1; |
| 551 | |
| 552 | if (kprobe_status & KPROBE_HIT_SS) { |
| 553 | resume_execution(current_kprobe, regs); |
| 554 | reset_current_kprobe(); |
| 555 | preempt_enable_no_resched(); |
| 556 | } |
| 557 | return 0; |
| 558 | } |
| 559 | |
| 560 | /* |
| 561 | * Wrapper routine to for handling exceptions. |
| 562 | */ |
| 563 | int __kprobes kprobe_exceptions_notify(struct notifier_block *self, |
| 564 | unsigned long val, void *data) |
| 565 | { |
| 566 | struct die_args *args = data; |
| 567 | |
| 568 | switch (val) { |
| 569 | case DIE_BREAKPOINT: |
| 570 | if (current_kprobe_bp_addr != args->regs->pc) { |
| 571 | if (kprobe_handler(args->regs)) |
| 572 | return NOTIFY_STOP; |
| 573 | } else { |
| 574 | if (post_kprobe_handler(args->regs)) |
| 575 | return NOTIFY_STOP; |
| 576 | } |
| 577 | break; |
| 578 | case DIE_GPF: |
| 579 | if (kprobe_running() && |
| 580 | kprobe_fault_handler(args->regs, args->trapnr)) |
| 581 | return NOTIFY_STOP; |
| 582 | break; |
| 583 | default: |
| 584 | break; |
| 585 | } |
| 586 | return NOTIFY_DONE; |
| 587 | } |
| 588 | |
| 589 | /* Jprobes support. */ |
| 590 | static struct pt_regs jprobe_saved_regs; |
| 591 | static struct pt_regs *jprobe_saved_regs_location; |
| 592 | static kprobe_opcode_t jprobe_saved_stack[MAX_STACK_SIZE]; |
| 593 | |
| 594 | int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) |
| 595 | { |
| 596 | struct jprobe *jp = container_of(p, struct jprobe, kp); |
| 597 | |
| 598 | jprobe_saved_regs_location = regs; |
| 599 | memcpy(&jprobe_saved_regs, regs, sizeof(struct pt_regs)); |
| 600 | |
| 601 | /* Save a whole stack frame, this gets arguments |
| 602 | * pushed onto the stack after using up all the |
| 603 | * arg registers. |
| 604 | */ |
| 605 | memcpy(&jprobe_saved_stack, regs + 1, sizeof(jprobe_saved_stack)); |
| 606 | |
| 607 | /* setup return addr to the jprobe handler routine */ |
| 608 | regs->pc = (unsigned long) jp->entry; |
| 609 | return 1; |
| 610 | } |
| 611 | |
| 612 | void __kprobes jprobe_return(void) |
| 613 | { |
| 614 | void *orig_sp = jprobe_saved_regs_location + 1; |
| 615 | |
| 616 | preempt_enable_no_resched(); |
| 617 | asm volatile(" mov %0,sp\n" |
| 618 | ".globl jprobe_return_bp_addr\n" |
| 619 | "jprobe_return_bp_addr:\n\t" |
| 620 | " .byte 0xff\n" |
| 621 | : : "d" (orig_sp)); |
| 622 | } |
| 623 | |
| 624 | extern void jprobe_return_bp_addr(void); |
| 625 | |
| 626 | int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) |
| 627 | { |
| 628 | u8 *addr = (u8 *) regs->pc; |
| 629 | |
| 630 | if (addr == (u8 *) jprobe_return_bp_addr) { |
| 631 | if (jprobe_saved_regs_location != regs) { |
| 632 | printk(KERN_ERR"JPROBE:" |
| 633 | " Current regs (%p) does not match saved regs" |
| 634 | " (%p).\n", |
| 635 | regs, jprobe_saved_regs_location); |
| 636 | BUG(); |
| 637 | } |
| 638 | |
| 639 | /* Restore old register state. |
| 640 | */ |
| 641 | memcpy(regs, &jprobe_saved_regs, sizeof(struct pt_regs)); |
| 642 | |
| 643 | memcpy(regs + 1, &jprobe_saved_stack, |
| 644 | sizeof(jprobe_saved_stack)); |
| 645 | return 1; |
| 646 | } |
| 647 | return 0; |
| 648 | } |
| 649 | |
| 650 | int __init arch_init_kprobes(void) |
| 651 | { |
| 652 | return 0; |
| 653 | } |