1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright 2008 Michael Ellerman, IBM Corporation. 4 */ 5 6 #include <linux/kernel.h> 7 #include <linux/kprobes.h> 8 #include <linux/vmalloc.h> 9 #include <linux/init.h> 10 #include <linux/mm.h> 11 #include <linux/cpuhotplug.h> 12 #include <linux/slab.h> 13 #include <linux/uaccess.h> 14 15 #include <asm/tlbflush.h> 16 #include <asm/page.h> 17 #include <asm/code-patching.h> 18 #include <asm/setup.h> 19 #include <asm/inst.h> 20 21 static int __patch_instruction(u32 *exec_addr, struct ppc_inst instr, u32 *patch_addr) 22 { 23 if (!ppc_inst_prefixed(instr)) { 24 u32 val = ppc_inst_val(instr); 25 26 __put_kernel_nofault(patch_addr, &val, u32, failed); 27 } else { 28 u64 val = ppc_inst_as_ulong(instr); 29 30 __put_kernel_nofault(patch_addr, &val, u64, failed); 31 } 32 33 asm ("dcbst 0, %0; sync; icbi 0,%1; sync; isync" :: "r" (patch_addr), 34 "r" (exec_addr)); 35 36 return 0; 37 38 failed: 39 return -EFAULT; 40 } 41 42 int raw_patch_instruction(u32 *addr, struct ppc_inst instr) 43 { 44 return __patch_instruction(addr, instr, addr); 45 } 46 47 #ifdef CONFIG_STRICT_KERNEL_RWX 48 static DEFINE_PER_CPU(struct vm_struct *, text_poke_area); 49 50 static int text_area_cpu_up(unsigned int cpu) 51 { 52 struct vm_struct *area; 53 54 area = get_vm_area(PAGE_SIZE, VM_ALLOC); 55 if (!area) { 56 WARN_ONCE(1, "Failed to create text area for cpu %d\n", 57 cpu); 58 return -1; 59 } 60 this_cpu_write(text_poke_area, area); 61 62 return 0; 63 } 64 65 static int text_area_cpu_down(unsigned int cpu) 66 { 67 free_vm_area(this_cpu_read(text_poke_area)); 68 return 0; 69 } 70 71 /* 72 * Although BUG_ON() is rude, in this case it should only happen if ENOMEM, and 73 * we judge it as being preferable to a kernel that will crash later when 74 * someone tries to use patch_instruction(). 75 */ 76 void __init poking_init(void) 77 { 78 BUG_ON(!cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, 79 "powerpc/text_poke:online", text_area_cpu_up, 80 text_area_cpu_down)); 81 } 82 83 /* 84 * This can be called for kernel text or a module. 85 */ 86 static int map_patch_area(void *addr, unsigned long text_poke_addr) 87 { 88 unsigned long pfn; 89 int err; 90 91 if (is_vmalloc_or_module_addr(addr)) 92 pfn = vmalloc_to_pfn(addr); 93 else 94 pfn = __pa_symbol(addr) >> PAGE_SHIFT; 95 96 err = map_kernel_page(text_poke_addr, (pfn << PAGE_SHIFT), PAGE_KERNEL); 97 98 pr_devel("Mapped addr %lx with pfn %lx:%d\n", text_poke_addr, pfn, err); 99 if (err) 100 return -1; 101 102 return 0; 103 } 104 105 static inline int unmap_patch_area(unsigned long addr) 106 { 107 pte_t *ptep; 108 pmd_t *pmdp; 109 pud_t *pudp; 110 p4d_t *p4dp; 111 pgd_t *pgdp; 112 113 pgdp = pgd_offset_k(addr); 114 if (unlikely(!pgdp)) 115 return -EINVAL; 116 117 p4dp = p4d_offset(pgdp, addr); 118 if (unlikely(!p4dp)) 119 return -EINVAL; 120 121 pudp = pud_offset(p4dp, addr); 122 if (unlikely(!pudp)) 123 return -EINVAL; 124 125 pmdp = pmd_offset(pudp, addr); 126 if (unlikely(!pmdp)) 127 return -EINVAL; 128 129 ptep = pte_offset_kernel(pmdp, addr); 130 if (unlikely(!ptep)) 131 return -EINVAL; 132 133 pr_devel("clearing mm %p, pte %p, addr %lx\n", &init_mm, ptep, addr); 134 135 /* 136 * In hash, pte_clear flushes the tlb, in radix, we have to 137 */ 138 pte_clear(&init_mm, addr, ptep); 139 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 140 141 return 0; 142 } 143 144 static int do_patch_instruction(u32 *addr, struct ppc_inst instr) 145 { 146 int err; 147 u32 *patch_addr = NULL; 148 unsigned long flags; 149 unsigned long text_poke_addr; 150 unsigned long kaddr = (unsigned long)addr; 151 152 /* 153 * During early early boot patch_instruction is called 154 * when text_poke_area is not ready, but we still need 155 * to allow patching. We just do the plain old patching 156 */ 157 if (!this_cpu_read(text_poke_area)) 158 return raw_patch_instruction(addr, instr); 159 160 local_irq_save(flags); 161 162 text_poke_addr = (unsigned long)__this_cpu_read(text_poke_area)->addr; 163 if (map_patch_area(addr, text_poke_addr)) { 164 err = -1; 165 goto out; 166 } 167 168 patch_addr = (u32 *)(text_poke_addr + (kaddr & ~PAGE_MASK)); 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(u32 *addr, struct ppc_inst instr) 184 { 185 return raw_patch_instruction(addr, instr); 186 } 187 188 #endif /* CONFIG_STRICT_KERNEL_RWX */ 189 190 int patch_instruction(u32 *addr, struct ppc_inst instr) 191 { 192 /* Make sure we aren't patching a freed init section */ 193 if (!kernel_text_address((unsigned long)addr)) 194 return 0; 195 196 return do_patch_instruction(addr, instr); 197 } 198 NOKPROBE_SYMBOL(patch_instruction); 199 200 int patch_branch(u32 *addr, unsigned long target, int flags) 201 { 202 struct ppc_inst instr; 203 204 create_branch(&instr, addr, target, flags); 205 return patch_instruction(addr, instr); 206 } 207 208 bool is_offset_in_branch_range(long offset) 209 { 210 /* 211 * Powerpc branch instruction is : 212 * 213 * 0 6 30 31 214 * +---------+----------------+---+---+ 215 * | opcode | LI |AA |LK | 216 * +---------+----------------+---+---+ 217 * Where AA = 0 and LK = 0 218 * 219 * LI is a signed 24 bits integer. The real branch offset is computed 220 * by: imm32 = SignExtend(LI:'0b00', 32); 221 * 222 * So the maximum forward branch should be: 223 * (0x007fffff << 2) = 0x01fffffc = 0x1fffffc 224 * The maximum backward branch should be: 225 * (0xff800000 << 2) = 0xfe000000 = -0x2000000 226 */ 227 return (offset >= -0x2000000 && offset <= 0x1fffffc && !(offset & 0x3)); 228 } 229 230 bool is_offset_in_cond_branch_range(long offset) 231 { 232 return offset >= -0x8000 && offset <= 0x7fff && !(offset & 0x3); 233 } 234 235 /* 236 * Helper to check if a given instruction is a conditional branch 237 * Derived from the conditional checks in analyse_instr() 238 */ 239 bool is_conditional_branch(struct ppc_inst instr) 240 { 241 unsigned int opcode = ppc_inst_primary_opcode(instr); 242 243 if (opcode == 16) /* bc, bca, bcl, bcla */ 244 return true; 245 if (opcode == 19) { 246 switch ((ppc_inst_val(instr) >> 1) & 0x3ff) { 247 case 16: /* bclr, bclrl */ 248 case 528: /* bcctr, bcctrl */ 249 case 560: /* bctar, bctarl */ 250 return true; 251 } 252 } 253 return false; 254 } 255 NOKPROBE_SYMBOL(is_conditional_branch); 256 257 int create_branch(struct ppc_inst *instr, const u32 *addr, 258 unsigned long target, int flags) 259 { 260 long offset; 261 262 *instr = ppc_inst(0); 263 offset = target; 264 if (! (flags & BRANCH_ABSOLUTE)) 265 offset = offset - (unsigned long)addr; 266 267 /* Check we can represent the target in the instruction format */ 268 if (!is_offset_in_branch_range(offset)) 269 return 1; 270 271 /* Mask out the flags and target, so they don't step on each other. */ 272 *instr = ppc_inst(0x48000000 | (flags & 0x3) | (offset & 0x03FFFFFC)); 273 274 return 0; 275 } 276 277 int create_cond_branch(struct ppc_inst *instr, const u32 *addr, 278 unsigned long target, int flags) 279 { 280 long offset; 281 282 offset = target; 283 if (! (flags & BRANCH_ABSOLUTE)) 284 offset = offset - (unsigned long)addr; 285 286 /* Check we can represent the target in the instruction format */ 287 if (!is_offset_in_cond_branch_range(offset)) 288 return 1; 289 290 /* Mask out the flags and target, so they don't step on each other. */ 291 *instr = ppc_inst(0x40000000 | (flags & 0x3FF0003) | (offset & 0xFFFC)); 292 293 return 0; 294 } 295 296 static unsigned int branch_opcode(struct ppc_inst instr) 297 { 298 return ppc_inst_primary_opcode(instr) & 0x3F; 299 } 300 301 static int instr_is_branch_iform(struct ppc_inst instr) 302 { 303 return branch_opcode(instr) == 18; 304 } 305 306 static int instr_is_branch_bform(struct ppc_inst instr) 307 { 308 return branch_opcode(instr) == 16; 309 } 310 311 int instr_is_relative_branch(struct ppc_inst instr) 312 { 313 if (ppc_inst_val(instr) & BRANCH_ABSOLUTE) 314 return 0; 315 316 return instr_is_branch_iform(instr) || instr_is_branch_bform(instr); 317 } 318 319 int instr_is_relative_link_branch(struct ppc_inst instr) 320 { 321 return instr_is_relative_branch(instr) && (ppc_inst_val(instr) & BRANCH_SET_LINK); 322 } 323 324 static unsigned long branch_iform_target(const u32 *instr) 325 { 326 signed long imm; 327 328 imm = ppc_inst_val(ppc_inst_read(instr)) & 0x3FFFFFC; 329 330 /* If the top bit of the immediate value is set this is negative */ 331 if (imm & 0x2000000) 332 imm -= 0x4000000; 333 334 if ((ppc_inst_val(ppc_inst_read(instr)) & BRANCH_ABSOLUTE) == 0) 335 imm += (unsigned long)instr; 336 337 return (unsigned long)imm; 338 } 339 340 static unsigned long branch_bform_target(const u32 *instr) 341 { 342 signed long imm; 343 344 imm = ppc_inst_val(ppc_inst_read(instr)) & 0xFFFC; 345 346 /* If the top bit of the immediate value is set this is negative */ 347 if (imm & 0x8000) 348 imm -= 0x10000; 349 350 if ((ppc_inst_val(ppc_inst_read(instr)) & BRANCH_ABSOLUTE) == 0) 351 imm += (unsigned long)instr; 352 353 return (unsigned long)imm; 354 } 355 356 unsigned long branch_target(const u32 *instr) 357 { 358 if (instr_is_branch_iform(ppc_inst_read(instr))) 359 return branch_iform_target(instr); 360 else if (instr_is_branch_bform(ppc_inst_read(instr))) 361 return branch_bform_target(instr); 362 363 return 0; 364 } 365 366 int translate_branch(struct ppc_inst *instr, const u32 *dest, const u32 *src) 367 { 368 unsigned long target; 369 target = branch_target(src); 370 371 if (instr_is_branch_iform(ppc_inst_read(src))) 372 return create_branch(instr, dest, target, 373 ppc_inst_val(ppc_inst_read(src))); 374 else if (instr_is_branch_bform(ppc_inst_read(src))) 375 return create_cond_branch(instr, dest, target, 376 ppc_inst_val(ppc_inst_read(src))); 377 378 return 1; 379 } 380 381 #ifdef CONFIG_PPC_BOOK3E_64 382 void __patch_exception(int exc, unsigned long addr) 383 { 384 extern unsigned int interrupt_base_book3e; 385 unsigned int *ibase = &interrupt_base_book3e; 386 387 /* Our exceptions vectors start with a NOP and -then- a branch 388 * to deal with single stepping from userspace which stops on 389 * the second instruction. Thus we need to patch the second 390 * instruction of the exception, not the first one 391 */ 392 393 patch_branch(ibase + (exc / 4) + 1, addr, 0); 394 } 395 #endif 396 397 #ifdef CONFIG_CODE_PATCHING_SELFTEST 398 399 static int instr_is_branch_to_addr(const u32 *instr, unsigned long addr) 400 { 401 if (instr_is_branch_iform(ppc_inst_read(instr)) || 402 instr_is_branch_bform(ppc_inst_read(instr))) 403 return branch_target(instr) == addr; 404 405 return 0; 406 } 407 408 static void __init test_trampoline(void) 409 { 410 asm ("nop;\n"); 411 } 412 413 #define check(x) \ 414 if (!(x)) printk("code-patching: test failed at line %d\n", __LINE__); 415 416 static void __init test_branch_iform(void) 417 { 418 int err; 419 struct ppc_inst instr; 420 u32 tmp[2]; 421 u32 *iptr = tmp; 422 unsigned long addr = (unsigned long)tmp; 423 424 /* The simplest case, branch to self, no flags */ 425 check(instr_is_branch_iform(ppc_inst(0x48000000))); 426 /* All bits of target set, and flags */ 427 check(instr_is_branch_iform(ppc_inst(0x4bffffff))); 428 /* High bit of opcode set, which is wrong */ 429 check(!instr_is_branch_iform(ppc_inst(0xcbffffff))); 430 /* Middle bits of opcode set, which is wrong */ 431 check(!instr_is_branch_iform(ppc_inst(0x7bffffff))); 432 433 /* Simplest case, branch to self with link */ 434 check(instr_is_branch_iform(ppc_inst(0x48000001))); 435 /* All bits of targets set */ 436 check(instr_is_branch_iform(ppc_inst(0x4bfffffd))); 437 /* Some bits of targets set */ 438 check(instr_is_branch_iform(ppc_inst(0x4bff00fd))); 439 /* Must be a valid branch to start with */ 440 check(!instr_is_branch_iform(ppc_inst(0x7bfffffd))); 441 442 /* Absolute branch to 0x100 */ 443 patch_instruction(iptr, ppc_inst(0x48000103)); 444 check(instr_is_branch_to_addr(iptr, 0x100)); 445 /* Absolute branch to 0x420fc */ 446 patch_instruction(iptr, ppc_inst(0x480420ff)); 447 check(instr_is_branch_to_addr(iptr, 0x420fc)); 448 /* Maximum positive relative branch, + 20MB - 4B */ 449 patch_instruction(iptr, ppc_inst(0x49fffffc)); 450 check(instr_is_branch_to_addr(iptr, addr + 0x1FFFFFC)); 451 /* Smallest negative relative branch, - 4B */ 452 patch_instruction(iptr, ppc_inst(0x4bfffffc)); 453 check(instr_is_branch_to_addr(iptr, addr - 4)); 454 /* Largest negative relative branch, - 32 MB */ 455 patch_instruction(iptr, ppc_inst(0x4a000000)); 456 check(instr_is_branch_to_addr(iptr, addr - 0x2000000)); 457 458 /* Branch to self, with link */ 459 err = create_branch(&instr, iptr, addr, BRANCH_SET_LINK); 460 patch_instruction(iptr, instr); 461 check(instr_is_branch_to_addr(iptr, addr)); 462 463 /* Branch to self - 0x100, with link */ 464 err = create_branch(&instr, iptr, addr - 0x100, BRANCH_SET_LINK); 465 patch_instruction(iptr, instr); 466 check(instr_is_branch_to_addr(iptr, addr - 0x100)); 467 468 /* Branch to self + 0x100, no link */ 469 err = create_branch(&instr, iptr, addr + 0x100, 0); 470 patch_instruction(iptr, instr); 471 check(instr_is_branch_to_addr(iptr, addr + 0x100)); 472 473 /* Maximum relative negative offset, - 32 MB */ 474 err = create_branch(&instr, iptr, addr - 0x2000000, BRANCH_SET_LINK); 475 patch_instruction(iptr, instr); 476 check(instr_is_branch_to_addr(iptr, addr - 0x2000000)); 477 478 /* Out of range relative negative offset, - 32 MB + 4*/ 479 err = create_branch(&instr, iptr, addr - 0x2000004, BRANCH_SET_LINK); 480 check(err); 481 482 /* Out of range relative positive offset, + 32 MB */ 483 err = create_branch(&instr, iptr, addr + 0x2000000, BRANCH_SET_LINK); 484 check(err); 485 486 /* Unaligned target */ 487 err = create_branch(&instr, iptr, addr + 3, BRANCH_SET_LINK); 488 check(err); 489 490 /* Check flags are masked correctly */ 491 err = create_branch(&instr, iptr, addr, 0xFFFFFFFC); 492 patch_instruction(iptr, instr); 493 check(instr_is_branch_to_addr(iptr, addr)); 494 check(ppc_inst_equal(instr, ppc_inst(0x48000000))); 495 } 496 497 static void __init test_create_function_call(void) 498 { 499 u32 *iptr; 500 unsigned long dest; 501 struct ppc_inst instr; 502 503 /* Check we can create a function call */ 504 iptr = (u32 *)ppc_function_entry(test_trampoline); 505 dest = ppc_function_entry(test_create_function_call); 506 create_branch(&instr, iptr, dest, BRANCH_SET_LINK); 507 patch_instruction(iptr, instr); 508 check(instr_is_branch_to_addr(iptr, dest)); 509 } 510 511 static void __init test_branch_bform(void) 512 { 513 int err; 514 unsigned long addr; 515 struct ppc_inst instr; 516 u32 tmp[2]; 517 u32 *iptr = tmp; 518 unsigned int flags; 519 520 addr = (unsigned long)iptr; 521 522 /* The simplest case, branch to self, no flags */ 523 check(instr_is_branch_bform(ppc_inst(0x40000000))); 524 /* All bits of target set, and flags */ 525 check(instr_is_branch_bform(ppc_inst(0x43ffffff))); 526 /* High bit of opcode set, which is wrong */ 527 check(!instr_is_branch_bform(ppc_inst(0xc3ffffff))); 528 /* Middle bits of opcode set, which is wrong */ 529 check(!instr_is_branch_bform(ppc_inst(0x7bffffff))); 530 531 /* Absolute conditional branch to 0x100 */ 532 patch_instruction(iptr, ppc_inst(0x43ff0103)); 533 check(instr_is_branch_to_addr(iptr, 0x100)); 534 /* Absolute conditional branch to 0x20fc */ 535 patch_instruction(iptr, ppc_inst(0x43ff20ff)); 536 check(instr_is_branch_to_addr(iptr, 0x20fc)); 537 /* Maximum positive relative conditional branch, + 32 KB - 4B */ 538 patch_instruction(iptr, ppc_inst(0x43ff7ffc)); 539 check(instr_is_branch_to_addr(iptr, addr + 0x7FFC)); 540 /* Smallest negative relative conditional branch, - 4B */ 541 patch_instruction(iptr, ppc_inst(0x43fffffc)); 542 check(instr_is_branch_to_addr(iptr, addr - 4)); 543 /* Largest negative relative conditional branch, - 32 KB */ 544 patch_instruction(iptr, ppc_inst(0x43ff8000)); 545 check(instr_is_branch_to_addr(iptr, addr - 0x8000)); 546 547 /* All condition code bits set & link */ 548 flags = 0x3ff000 | BRANCH_SET_LINK; 549 550 /* Branch to self */ 551 err = create_cond_branch(&instr, iptr, addr, flags); 552 patch_instruction(iptr, instr); 553 check(instr_is_branch_to_addr(iptr, addr)); 554 555 /* Branch to self - 0x100 */ 556 err = create_cond_branch(&instr, iptr, addr - 0x100, flags); 557 patch_instruction(iptr, instr); 558 check(instr_is_branch_to_addr(iptr, addr - 0x100)); 559 560 /* Branch to self + 0x100 */ 561 err = create_cond_branch(&instr, iptr, addr + 0x100, flags); 562 patch_instruction(iptr, instr); 563 check(instr_is_branch_to_addr(iptr, addr + 0x100)); 564 565 /* Maximum relative negative offset, - 32 KB */ 566 err = create_cond_branch(&instr, iptr, addr - 0x8000, flags); 567 patch_instruction(iptr, instr); 568 check(instr_is_branch_to_addr(iptr, addr - 0x8000)); 569 570 /* Out of range relative negative offset, - 32 KB + 4*/ 571 err = create_cond_branch(&instr, iptr, addr - 0x8004, flags); 572 check(err); 573 574 /* Out of range relative positive offset, + 32 KB */ 575 err = create_cond_branch(&instr, iptr, addr + 0x8000, flags); 576 check(err); 577 578 /* Unaligned target */ 579 err = create_cond_branch(&instr, iptr, addr + 3, flags); 580 check(err); 581 582 /* Check flags are masked correctly */ 583 err = create_cond_branch(&instr, iptr, addr, 0xFFFFFFFC); 584 patch_instruction(iptr, instr); 585 check(instr_is_branch_to_addr(iptr, addr)); 586 check(ppc_inst_equal(instr, ppc_inst(0x43FF0000))); 587 } 588 589 static void __init test_translate_branch(void) 590 { 591 unsigned long addr; 592 void *p, *q; 593 struct ppc_inst instr; 594 void *buf; 595 596 buf = vmalloc(PAGE_ALIGN(0x2000000 + 1)); 597 check(buf); 598 if (!buf) 599 return; 600 601 /* Simple case, branch to self moved a little */ 602 p = buf; 603 addr = (unsigned long)p; 604 patch_branch(p, addr, 0); 605 check(instr_is_branch_to_addr(p, addr)); 606 q = p + 4; 607 translate_branch(&instr, q, p); 608 patch_instruction(q, instr); 609 check(instr_is_branch_to_addr(q, addr)); 610 611 /* Maximum negative case, move b . to addr + 32 MB */ 612 p = buf; 613 addr = (unsigned long)p; 614 patch_branch(p, addr, 0); 615 q = buf + 0x2000000; 616 translate_branch(&instr, q, p); 617 patch_instruction(q, instr); 618 check(instr_is_branch_to_addr(p, addr)); 619 check(instr_is_branch_to_addr(q, addr)); 620 check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x4a000000))); 621 622 /* Maximum positive case, move x to x - 32 MB + 4 */ 623 p = buf + 0x2000000; 624 addr = (unsigned long)p; 625 patch_branch(p, addr, 0); 626 q = buf + 4; 627 translate_branch(&instr, q, p); 628 patch_instruction(q, instr); 629 check(instr_is_branch_to_addr(p, addr)); 630 check(instr_is_branch_to_addr(q, addr)); 631 check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x49fffffc))); 632 633 /* Jump to x + 16 MB moved to x + 20 MB */ 634 p = buf; 635 addr = 0x1000000 + (unsigned long)buf; 636 patch_branch(p, addr, BRANCH_SET_LINK); 637 q = buf + 0x1400000; 638 translate_branch(&instr, q, p); 639 patch_instruction(q, instr); 640 check(instr_is_branch_to_addr(p, addr)); 641 check(instr_is_branch_to_addr(q, addr)); 642 643 /* Jump to x + 16 MB moved to x - 16 MB + 4 */ 644 p = buf + 0x1000000; 645 addr = 0x2000000 + (unsigned long)buf; 646 patch_branch(p, addr, 0); 647 q = buf + 4; 648 translate_branch(&instr, q, p); 649 patch_instruction(q, instr); 650 check(instr_is_branch_to_addr(p, addr)); 651 check(instr_is_branch_to_addr(q, addr)); 652 653 654 /* Conditional branch tests */ 655 656 /* Simple case, branch to self moved a little */ 657 p = buf; 658 addr = (unsigned long)p; 659 create_cond_branch(&instr, p, addr, 0); 660 patch_instruction(p, instr); 661 check(instr_is_branch_to_addr(p, addr)); 662 q = buf + 4; 663 translate_branch(&instr, q, p); 664 patch_instruction(q, instr); 665 check(instr_is_branch_to_addr(q, addr)); 666 667 /* Maximum negative case, move b . to addr + 32 KB */ 668 p = buf; 669 addr = (unsigned long)p; 670 create_cond_branch(&instr, p, addr, 0xFFFFFFFC); 671 patch_instruction(p, instr); 672 q = buf + 0x8000; 673 translate_branch(&instr, q, p); 674 patch_instruction(q, instr); 675 check(instr_is_branch_to_addr(p, addr)); 676 check(instr_is_branch_to_addr(q, addr)); 677 check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff8000))); 678 679 /* Maximum positive case, move x to x - 32 KB + 4 */ 680 p = buf + 0x8000; 681 addr = (unsigned long)p; 682 create_cond_branch(&instr, p, addr, 0xFFFFFFFC); 683 patch_instruction(p, instr); 684 q = buf + 4; 685 translate_branch(&instr, q, p); 686 patch_instruction(q, instr); 687 check(instr_is_branch_to_addr(p, addr)); 688 check(instr_is_branch_to_addr(q, addr)); 689 check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff7ffc))); 690 691 /* Jump to x + 12 KB moved to x + 20 KB */ 692 p = buf; 693 addr = 0x3000 + (unsigned long)buf; 694 create_cond_branch(&instr, p, addr, BRANCH_SET_LINK); 695 patch_instruction(p, instr); 696 q = buf + 0x5000; 697 translate_branch(&instr, q, p); 698 patch_instruction(q, instr); 699 check(instr_is_branch_to_addr(p, addr)); 700 check(instr_is_branch_to_addr(q, addr)); 701 702 /* Jump to x + 8 KB moved to x - 8 KB + 4 */ 703 p = buf + 0x2000; 704 addr = 0x4000 + (unsigned long)buf; 705 create_cond_branch(&instr, p, addr, 0); 706 patch_instruction(p, instr); 707 q = buf + 4; 708 translate_branch(&instr, q, p); 709 patch_instruction(q, instr); 710 check(instr_is_branch_to_addr(p, addr)); 711 check(instr_is_branch_to_addr(q, addr)); 712 713 /* Free the buffer we were using */ 714 vfree(buf); 715 } 716 717 #ifdef CONFIG_PPC64 718 static void __init test_prefixed_patching(void) 719 { 720 extern unsigned int code_patching_test1[]; 721 extern unsigned int code_patching_test1_expected[]; 722 extern unsigned int end_code_patching_test1[]; 723 724 __patch_instruction(code_patching_test1, 725 ppc_inst_prefix(OP_PREFIX << 26, 0x00000000), 726 code_patching_test1); 727 728 check(!memcmp(code_patching_test1, 729 code_patching_test1_expected, 730 sizeof(unsigned int) * 731 (end_code_patching_test1 - code_patching_test1))); 732 } 733 #else 734 static inline void test_prefixed_patching(void) {} 735 #endif 736 737 static int __init test_code_patching(void) 738 { 739 printk(KERN_DEBUG "Running code patching self-tests ...\n"); 740 741 test_branch_iform(); 742 test_branch_bform(); 743 test_create_function_call(); 744 test_translate_branch(); 745 test_prefixed_patching(); 746 747 return 0; 748 } 749 late_initcall(test_code_patching); 750 751 #endif /* CONFIG_CODE_PATCHING_SELFTEST */ 752