1 /* 2 * Copyright 2008 Michael Ellerman, IBM Corporation. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 7 * 2 of the License, or (at your option) any later version. 8 */ 9 10 #include <linux/kernel.h> 11 #include <linux/kprobes.h> 12 #include <linux/vmalloc.h> 13 #include <linux/init.h> 14 #include <linux/mm.h> 15 #include <linux/cpuhotplug.h> 16 #include <linux/slab.h> 17 #include <linux/uaccess.h> 18 19 #include <asm/pgtable.h> 20 #include <asm/tlbflush.h> 21 #include <asm/page.h> 22 #include <asm/code-patching.h> 23 #include <asm/setup.h> 24 25 static int __patch_instruction(unsigned int *exec_addr, unsigned int instr, 26 unsigned int *patch_addr) 27 { 28 int err = 0; 29 30 __put_user_asm(instr, patch_addr, err, "stw"); 31 if (err) 32 return err; 33 34 asm ("dcbst 0, %0; sync; icbi 0,%1; sync; isync" :: "r" (patch_addr), 35 "r" (exec_addr)); 36 37 return 0; 38 } 39 40 int raw_patch_instruction(unsigned int *addr, unsigned int instr) 41 { 42 return __patch_instruction(addr, instr, addr); 43 } 44 45 #ifdef CONFIG_STRICT_KERNEL_RWX 46 static DEFINE_PER_CPU(struct vm_struct *, text_poke_area); 47 48 static int text_area_cpu_up(unsigned int cpu) 49 { 50 struct vm_struct *area; 51 52 area = get_vm_area(PAGE_SIZE, VM_ALLOC); 53 if (!area) { 54 WARN_ONCE(1, "Failed to create text area for cpu %d\n", 55 cpu); 56 return -1; 57 } 58 this_cpu_write(text_poke_area, area); 59 60 return 0; 61 } 62 63 static int text_area_cpu_down(unsigned int cpu) 64 { 65 free_vm_area(this_cpu_read(text_poke_area)); 66 return 0; 67 } 68 69 /* 70 * Run as a late init call. This allows all the boot time patching to be done 71 * simply by patching the code, and then we're called here prior to 72 * mark_rodata_ro(), which happens after all init calls are run. Although 73 * BUG_ON() is rude, in this case it should only happen if ENOMEM, and we judge 74 * it as being preferable to a kernel that will crash later when someone tries 75 * to use patch_instruction(). 76 */ 77 static int __init setup_text_poke_area(void) 78 { 79 BUG_ON(!cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, 80 "powerpc/text_poke:online", text_area_cpu_up, 81 text_area_cpu_down)); 82 83 return 0; 84 } 85 late_initcall(setup_text_poke_area); 86 87 /* 88 * This can be called for kernel text or a module. 89 */ 90 static int map_patch_area(void *addr, unsigned long text_poke_addr) 91 { 92 unsigned long pfn; 93 int err; 94 95 if (is_vmalloc_addr(addr)) 96 pfn = vmalloc_to_pfn(addr); 97 else 98 pfn = __pa_symbol(addr) >> PAGE_SHIFT; 99 100 err = map_kernel_page(text_poke_addr, (pfn << PAGE_SHIFT), PAGE_KERNEL); 101 102 pr_devel("Mapped addr %lx with pfn %lx:%d\n", text_poke_addr, pfn, err); 103 if (err) 104 return -1; 105 106 return 0; 107 } 108 109 static inline int unmap_patch_area(unsigned long addr) 110 { 111 pte_t *ptep; 112 pmd_t *pmdp; 113 pud_t *pudp; 114 pgd_t *pgdp; 115 116 pgdp = pgd_offset_k(addr); 117 if (unlikely(!pgdp)) 118 return -EINVAL; 119 120 pudp = pud_offset(pgdp, addr); 121 if (unlikely(!pudp)) 122 return -EINVAL; 123 124 pmdp = pmd_offset(pudp, addr); 125 if (unlikely(!pmdp)) 126 return -EINVAL; 127 128 ptep = pte_offset_kernel(pmdp, addr); 129 if (unlikely(!ptep)) 130 return -EINVAL; 131 132 pr_devel("clearing mm %p, pte %p, addr %lx\n", &init_mm, ptep, addr); 133 134 /* 135 * In hash, pte_clear flushes the tlb, in radix, we have to 136 */ 137 pte_clear(&init_mm, addr, ptep); 138 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 139 140 return 0; 141 } 142 143 static int do_patch_instruction(unsigned int *addr, unsigned int instr) 144 { 145 int err; 146 unsigned int *patch_addr = NULL; 147 unsigned long flags; 148 unsigned long text_poke_addr; 149 unsigned long kaddr = (unsigned long)addr; 150 151 /* 152 * During early early boot patch_instruction is called 153 * when text_poke_area is not ready, but we still need 154 * to allow patching. We just do the plain old patching 155 */ 156 if (!this_cpu_read(text_poke_area)) 157 return raw_patch_instruction(addr, instr); 158 159 local_irq_save(flags); 160 161 text_poke_addr = (unsigned long)__this_cpu_read(text_poke_area)->addr; 162 if (map_patch_area(addr, text_poke_addr)) { 163 err = -1; 164 goto out; 165 } 166 167 patch_addr = (unsigned int *)(text_poke_addr) + 168 ((kaddr & ~PAGE_MASK) / sizeof(unsigned int)); 169 170 __patch_instruction(addr, instr, patch_addr); 171 172 err = unmap_patch_area(text_poke_addr); 173 if (err) 174 pr_warn("failed to unmap %lx\n", text_poke_addr); 175 176 out: 177 local_irq_restore(flags); 178 179 return err; 180 } 181 #else /* !CONFIG_STRICT_KERNEL_RWX */ 182 183 static int do_patch_instruction(unsigned int *addr, unsigned int instr) 184 { 185 return raw_patch_instruction(addr, instr); 186 } 187 188 #endif /* CONFIG_STRICT_KERNEL_RWX */ 189 190 int patch_instruction(unsigned int *addr, unsigned int instr) 191 { 192 /* Make sure we aren't patching a freed init section */ 193 if (init_mem_is_free && init_section_contains(addr, 4)) { 194 pr_debug("Skipping init section patching addr: 0x%px\n", addr); 195 return 0; 196 } 197 return do_patch_instruction(addr, instr); 198 } 199 NOKPROBE_SYMBOL(patch_instruction); 200 201 int patch_branch(unsigned int *addr, unsigned long target, int flags) 202 { 203 return patch_instruction(addr, create_branch(addr, target, flags)); 204 } 205 206 bool is_offset_in_branch_range(long offset) 207 { 208 /* 209 * Powerpc branch instruction is : 210 * 211 * 0 6 30 31 212 * +---------+----------------+---+---+ 213 * | opcode | LI |AA |LK | 214 * +---------+----------------+---+---+ 215 * Where AA = 0 and LK = 0 216 * 217 * LI is a signed 24 bits integer. The real branch offset is computed 218 * by: imm32 = SignExtend(LI:'0b00', 32); 219 * 220 * So the maximum forward branch should be: 221 * (0x007fffff << 2) = 0x01fffffc = 0x1fffffc 222 * The maximum backward branch should be: 223 * (0xff800000 << 2) = 0xfe000000 = -0x2000000 224 */ 225 return (offset >= -0x2000000 && offset <= 0x1fffffc && !(offset & 0x3)); 226 } 227 228 /* 229 * Helper to check if a given instruction is a conditional branch 230 * Derived from the conditional checks in analyse_instr() 231 */ 232 bool is_conditional_branch(unsigned int instr) 233 { 234 unsigned int opcode = instr >> 26; 235 236 if (opcode == 16) /* bc, bca, bcl, bcla */ 237 return true; 238 if (opcode == 19) { 239 switch ((instr >> 1) & 0x3ff) { 240 case 16: /* bclr, bclrl */ 241 case 528: /* bcctr, bcctrl */ 242 case 560: /* bctar, bctarl */ 243 return true; 244 } 245 } 246 return false; 247 } 248 NOKPROBE_SYMBOL(is_conditional_branch); 249 250 unsigned int create_branch(const unsigned int *addr, 251 unsigned long target, int flags) 252 { 253 unsigned int instruction; 254 long offset; 255 256 offset = target; 257 if (! (flags & BRANCH_ABSOLUTE)) 258 offset = offset - (unsigned long)addr; 259 260 /* Check we can represent the target in the instruction format */ 261 if (!is_offset_in_branch_range(offset)) 262 return 0; 263 264 /* Mask out the flags and target, so they don't step on each other. */ 265 instruction = 0x48000000 | (flags & 0x3) | (offset & 0x03FFFFFC); 266 267 return instruction; 268 } 269 270 unsigned int create_cond_branch(const unsigned int *addr, 271 unsigned long target, int flags) 272 { 273 unsigned int instruction; 274 long offset; 275 276 offset = target; 277 if (! (flags & BRANCH_ABSOLUTE)) 278 offset = offset - (unsigned long)addr; 279 280 /* Check we can represent the target in the instruction format */ 281 if (offset < -0x8000 || offset > 0x7FFF || offset & 0x3) 282 return 0; 283 284 /* Mask out the flags and target, so they don't step on each other. */ 285 instruction = 0x40000000 | (flags & 0x3FF0003) | (offset & 0xFFFC); 286 287 return instruction; 288 } 289 290 static unsigned int branch_opcode(unsigned int instr) 291 { 292 return (instr >> 26) & 0x3F; 293 } 294 295 static int instr_is_branch_iform(unsigned int instr) 296 { 297 return branch_opcode(instr) == 18; 298 } 299 300 static int instr_is_branch_bform(unsigned int instr) 301 { 302 return branch_opcode(instr) == 16; 303 } 304 305 int instr_is_relative_branch(unsigned int instr) 306 { 307 if (instr & BRANCH_ABSOLUTE) 308 return 0; 309 310 return instr_is_branch_iform(instr) || instr_is_branch_bform(instr); 311 } 312 313 int instr_is_relative_link_branch(unsigned int instr) 314 { 315 return instr_is_relative_branch(instr) && (instr & BRANCH_SET_LINK); 316 } 317 318 static unsigned long branch_iform_target(const unsigned int *instr) 319 { 320 signed long imm; 321 322 imm = *instr & 0x3FFFFFC; 323 324 /* If the top bit of the immediate value is set this is negative */ 325 if (imm & 0x2000000) 326 imm -= 0x4000000; 327 328 if ((*instr & BRANCH_ABSOLUTE) == 0) 329 imm += (unsigned long)instr; 330 331 return (unsigned long)imm; 332 } 333 334 static unsigned long branch_bform_target(const unsigned int *instr) 335 { 336 signed long imm; 337 338 imm = *instr & 0xFFFC; 339 340 /* If the top bit of the immediate value is set this is negative */ 341 if (imm & 0x8000) 342 imm -= 0x10000; 343 344 if ((*instr & BRANCH_ABSOLUTE) == 0) 345 imm += (unsigned long)instr; 346 347 return (unsigned long)imm; 348 } 349 350 unsigned long branch_target(const unsigned int *instr) 351 { 352 if (instr_is_branch_iform(*instr)) 353 return branch_iform_target(instr); 354 else if (instr_is_branch_bform(*instr)) 355 return branch_bform_target(instr); 356 357 return 0; 358 } 359 360 int instr_is_branch_to_addr(const unsigned int *instr, unsigned long addr) 361 { 362 if (instr_is_branch_iform(*instr) || instr_is_branch_bform(*instr)) 363 return branch_target(instr) == addr; 364 365 return 0; 366 } 367 368 unsigned int translate_branch(const unsigned int *dest, const unsigned int *src) 369 { 370 unsigned long target; 371 372 target = branch_target(src); 373 374 if (instr_is_branch_iform(*src)) 375 return create_branch(dest, target, *src); 376 else if (instr_is_branch_bform(*src)) 377 return create_cond_branch(dest, target, *src); 378 379 return 0; 380 } 381 382 #ifdef CONFIG_PPC_BOOK3E_64 383 void __patch_exception(int exc, unsigned long addr) 384 { 385 extern unsigned int interrupt_base_book3e; 386 unsigned int *ibase = &interrupt_base_book3e; 387 388 /* Our exceptions vectors start with a NOP and -then- a branch 389 * to deal with single stepping from userspace which stops on 390 * the second instruction. Thus we need to patch the second 391 * instruction of the exception, not the first one 392 */ 393 394 patch_branch(ibase + (exc / 4) + 1, addr, 0); 395 } 396 #endif 397 398 #ifdef CONFIG_CODE_PATCHING_SELFTEST 399 400 static void __init test_trampoline(void) 401 { 402 asm ("nop;\n"); 403 } 404 405 #define check(x) \ 406 if (!(x)) printk("code-patching: test failed at line %d\n", __LINE__); 407 408 static void __init test_branch_iform(void) 409 { 410 unsigned int instr; 411 unsigned long addr; 412 413 addr = (unsigned long)&instr; 414 415 /* The simplest case, branch to self, no flags */ 416 check(instr_is_branch_iform(0x48000000)); 417 /* All bits of target set, and flags */ 418 check(instr_is_branch_iform(0x4bffffff)); 419 /* High bit of opcode set, which is wrong */ 420 check(!instr_is_branch_iform(0xcbffffff)); 421 /* Middle bits of opcode set, which is wrong */ 422 check(!instr_is_branch_iform(0x7bffffff)); 423 424 /* Simplest case, branch to self with link */ 425 check(instr_is_branch_iform(0x48000001)); 426 /* All bits of targets set */ 427 check(instr_is_branch_iform(0x4bfffffd)); 428 /* Some bits of targets set */ 429 check(instr_is_branch_iform(0x4bff00fd)); 430 /* Must be a valid branch to start with */ 431 check(!instr_is_branch_iform(0x7bfffffd)); 432 433 /* Absolute branch to 0x100 */ 434 instr = 0x48000103; 435 check(instr_is_branch_to_addr(&instr, 0x100)); 436 /* Absolute branch to 0x420fc */ 437 instr = 0x480420ff; 438 check(instr_is_branch_to_addr(&instr, 0x420fc)); 439 /* Maximum positive relative branch, + 20MB - 4B */ 440 instr = 0x49fffffc; 441 check(instr_is_branch_to_addr(&instr, addr + 0x1FFFFFC)); 442 /* Smallest negative relative branch, - 4B */ 443 instr = 0x4bfffffc; 444 check(instr_is_branch_to_addr(&instr, addr - 4)); 445 /* Largest negative relative branch, - 32 MB */ 446 instr = 0x4a000000; 447 check(instr_is_branch_to_addr(&instr, addr - 0x2000000)); 448 449 /* Branch to self, with link */ 450 instr = create_branch(&instr, addr, BRANCH_SET_LINK); 451 check(instr_is_branch_to_addr(&instr, addr)); 452 453 /* Branch to self - 0x100, with link */ 454 instr = create_branch(&instr, addr - 0x100, BRANCH_SET_LINK); 455 check(instr_is_branch_to_addr(&instr, addr - 0x100)); 456 457 /* Branch to self + 0x100, no link */ 458 instr = create_branch(&instr, addr + 0x100, 0); 459 check(instr_is_branch_to_addr(&instr, addr + 0x100)); 460 461 /* Maximum relative negative offset, - 32 MB */ 462 instr = create_branch(&instr, addr - 0x2000000, BRANCH_SET_LINK); 463 check(instr_is_branch_to_addr(&instr, addr - 0x2000000)); 464 465 /* Out of range relative negative offset, - 32 MB + 4*/ 466 instr = create_branch(&instr, addr - 0x2000004, BRANCH_SET_LINK); 467 check(instr == 0); 468 469 /* Out of range relative positive offset, + 32 MB */ 470 instr = create_branch(&instr, addr + 0x2000000, BRANCH_SET_LINK); 471 check(instr == 0); 472 473 /* Unaligned target */ 474 instr = create_branch(&instr, addr + 3, BRANCH_SET_LINK); 475 check(instr == 0); 476 477 /* Check flags are masked correctly */ 478 instr = create_branch(&instr, addr, 0xFFFFFFFC); 479 check(instr_is_branch_to_addr(&instr, addr)); 480 check(instr == 0x48000000); 481 } 482 483 static void __init test_create_function_call(void) 484 { 485 unsigned int *iptr; 486 unsigned long dest; 487 488 /* Check we can create a function call */ 489 iptr = (unsigned int *)ppc_function_entry(test_trampoline); 490 dest = ppc_function_entry(test_create_function_call); 491 patch_instruction(iptr, create_branch(iptr, dest, BRANCH_SET_LINK)); 492 check(instr_is_branch_to_addr(iptr, dest)); 493 } 494 495 static void __init test_branch_bform(void) 496 { 497 unsigned long addr; 498 unsigned int *iptr, instr, flags; 499 500 iptr = &instr; 501 addr = (unsigned long)iptr; 502 503 /* The simplest case, branch to self, no flags */ 504 check(instr_is_branch_bform(0x40000000)); 505 /* All bits of target set, and flags */ 506 check(instr_is_branch_bform(0x43ffffff)); 507 /* High bit of opcode set, which is wrong */ 508 check(!instr_is_branch_bform(0xc3ffffff)); 509 /* Middle bits of opcode set, which is wrong */ 510 check(!instr_is_branch_bform(0x7bffffff)); 511 512 /* Absolute conditional branch to 0x100 */ 513 instr = 0x43ff0103; 514 check(instr_is_branch_to_addr(&instr, 0x100)); 515 /* Absolute conditional branch to 0x20fc */ 516 instr = 0x43ff20ff; 517 check(instr_is_branch_to_addr(&instr, 0x20fc)); 518 /* Maximum positive relative conditional branch, + 32 KB - 4B */ 519 instr = 0x43ff7ffc; 520 check(instr_is_branch_to_addr(&instr, addr + 0x7FFC)); 521 /* Smallest negative relative conditional branch, - 4B */ 522 instr = 0x43fffffc; 523 check(instr_is_branch_to_addr(&instr, addr - 4)); 524 /* Largest negative relative conditional branch, - 32 KB */ 525 instr = 0x43ff8000; 526 check(instr_is_branch_to_addr(&instr, addr - 0x8000)); 527 528 /* All condition code bits set & link */ 529 flags = 0x3ff000 | BRANCH_SET_LINK; 530 531 /* Branch to self */ 532 instr = create_cond_branch(iptr, addr, flags); 533 check(instr_is_branch_to_addr(&instr, addr)); 534 535 /* Branch to self - 0x100 */ 536 instr = create_cond_branch(iptr, addr - 0x100, flags); 537 check(instr_is_branch_to_addr(&instr, addr - 0x100)); 538 539 /* Branch to self + 0x100 */ 540 instr = create_cond_branch(iptr, addr + 0x100, flags); 541 check(instr_is_branch_to_addr(&instr, addr + 0x100)); 542 543 /* Maximum relative negative offset, - 32 KB */ 544 instr = create_cond_branch(iptr, addr - 0x8000, flags); 545 check(instr_is_branch_to_addr(&instr, addr - 0x8000)); 546 547 /* Out of range relative negative offset, - 32 KB + 4*/ 548 instr = create_cond_branch(iptr, addr - 0x8004, flags); 549 check(instr == 0); 550 551 /* Out of range relative positive offset, + 32 KB */ 552 instr = create_cond_branch(iptr, addr + 0x8000, flags); 553 check(instr == 0); 554 555 /* Unaligned target */ 556 instr = create_cond_branch(iptr, addr + 3, flags); 557 check(instr == 0); 558 559 /* Check flags are masked correctly */ 560 instr = create_cond_branch(iptr, addr, 0xFFFFFFFC); 561 check(instr_is_branch_to_addr(&instr, addr)); 562 check(instr == 0x43FF0000); 563 } 564 565 static void __init test_translate_branch(void) 566 { 567 unsigned long addr; 568 unsigned int *p, *q; 569 void *buf; 570 571 buf = vmalloc(PAGE_ALIGN(0x2000000 + 1)); 572 check(buf); 573 if (!buf) 574 return; 575 576 /* Simple case, branch to self moved a little */ 577 p = buf; 578 addr = (unsigned long)p; 579 patch_branch(p, addr, 0); 580 check(instr_is_branch_to_addr(p, addr)); 581 q = p + 1; 582 patch_instruction(q, translate_branch(q, p)); 583 check(instr_is_branch_to_addr(q, addr)); 584 585 /* Maximum negative case, move b . to addr + 32 MB */ 586 p = buf; 587 addr = (unsigned long)p; 588 patch_branch(p, addr, 0); 589 q = buf + 0x2000000; 590 patch_instruction(q, translate_branch(q, p)); 591 check(instr_is_branch_to_addr(p, addr)); 592 check(instr_is_branch_to_addr(q, addr)); 593 check(*q == 0x4a000000); 594 595 /* Maximum positive case, move x to x - 32 MB + 4 */ 596 p = buf + 0x2000000; 597 addr = (unsigned long)p; 598 patch_branch(p, addr, 0); 599 q = buf + 4; 600 patch_instruction(q, translate_branch(q, p)); 601 check(instr_is_branch_to_addr(p, addr)); 602 check(instr_is_branch_to_addr(q, addr)); 603 check(*q == 0x49fffffc); 604 605 /* Jump to x + 16 MB moved to x + 20 MB */ 606 p = buf; 607 addr = 0x1000000 + (unsigned long)buf; 608 patch_branch(p, addr, BRANCH_SET_LINK); 609 q = buf + 0x1400000; 610 patch_instruction(q, translate_branch(q, p)); 611 check(instr_is_branch_to_addr(p, addr)); 612 check(instr_is_branch_to_addr(q, addr)); 613 614 /* Jump to x + 16 MB moved to x - 16 MB + 4 */ 615 p = buf + 0x1000000; 616 addr = 0x2000000 + (unsigned long)buf; 617 patch_branch(p, addr, 0); 618 q = buf + 4; 619 patch_instruction(q, translate_branch(q, p)); 620 check(instr_is_branch_to_addr(p, addr)); 621 check(instr_is_branch_to_addr(q, addr)); 622 623 624 /* Conditional branch tests */ 625 626 /* Simple case, branch to self moved a little */ 627 p = buf; 628 addr = (unsigned long)p; 629 patch_instruction(p, create_cond_branch(p, addr, 0)); 630 check(instr_is_branch_to_addr(p, addr)); 631 q = p + 1; 632 patch_instruction(q, translate_branch(q, p)); 633 check(instr_is_branch_to_addr(q, addr)); 634 635 /* Maximum negative case, move b . to addr + 32 KB */ 636 p = buf; 637 addr = (unsigned long)p; 638 patch_instruction(p, create_cond_branch(p, addr, 0xFFFFFFFC)); 639 q = buf + 0x8000; 640 patch_instruction(q, translate_branch(q, p)); 641 check(instr_is_branch_to_addr(p, addr)); 642 check(instr_is_branch_to_addr(q, addr)); 643 check(*q == 0x43ff8000); 644 645 /* Maximum positive case, move x to x - 32 KB + 4 */ 646 p = buf + 0x8000; 647 addr = (unsigned long)p; 648 patch_instruction(p, create_cond_branch(p, addr, 0xFFFFFFFC)); 649 q = buf + 4; 650 patch_instruction(q, translate_branch(q, p)); 651 check(instr_is_branch_to_addr(p, addr)); 652 check(instr_is_branch_to_addr(q, addr)); 653 check(*q == 0x43ff7ffc); 654 655 /* Jump to x + 12 KB moved to x + 20 KB */ 656 p = buf; 657 addr = 0x3000 + (unsigned long)buf; 658 patch_instruction(p, create_cond_branch(p, addr, BRANCH_SET_LINK)); 659 q = buf + 0x5000; 660 patch_instruction(q, translate_branch(q, p)); 661 check(instr_is_branch_to_addr(p, addr)); 662 check(instr_is_branch_to_addr(q, addr)); 663 664 /* Jump to x + 8 KB moved to x - 8 KB + 4 */ 665 p = buf + 0x2000; 666 addr = 0x4000 + (unsigned long)buf; 667 patch_instruction(p, create_cond_branch(p, addr, 0)); 668 q = buf + 4; 669 patch_instruction(q, translate_branch(q, p)); 670 check(instr_is_branch_to_addr(p, addr)); 671 check(instr_is_branch_to_addr(q, addr)); 672 673 /* Free the buffer we were using */ 674 vfree(buf); 675 } 676 677 static int __init test_code_patching(void) 678 { 679 printk(KERN_DEBUG "Running code patching self-tests ...\n"); 680 681 test_branch_iform(); 682 test_branch_bform(); 683 test_create_function_call(); 684 test_translate_branch(); 685 686 return 0; 687 } 688 late_initcall(test_code_patching); 689 690 #endif /* CONFIG_CODE_PATCHING_SELFTEST */ 691