arch/powerpc/lib/code-patching.c

   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 (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(u32 *addr, unsigned long target, int flags)
 202 {
 203         struct ppc_inst instr;
 204
 205         create_branch(&instr, addr, target, flags);
 206         return patch_instruction(addr, instr);
 207 }
 208
 209 bool is_offset_in_branch_range(long offset)
 210 {
 211         /*
 212          * Powerpc branch instruction is :
 213          *
 214          *  0         6                 30   31
 215          *  +---------+----------------+---+---+
 216          *  | opcode  |     LI         |AA |LK |
 217          *  +---------+----------------+---+---+
 218          *  Where AA = 0 and LK = 0
 219          *
 220          * LI is a signed 24 bits integer. The real branch offset is computed
 221          * by: imm32 = SignExtend(LI:'0b00', 32);
 222          *
 223          * So the maximum forward branch should be:
 224          *   (0x007fffff << 2) = 0x01fffffc =  0x1fffffc
 225          * The maximum backward branch should be:
 226          *   (0xff800000 << 2) = 0xfe000000 = -0x2000000
 227          */
 228         return (offset >= -0x2000000 && offset <= 0x1fffffc && !(offset & 0x3));
 229 }
 230
 231 bool is_offset_in_cond_branch_range(long offset)
 232 {
 233         return offset >= -0x8000 && offset <= 0x7fff && !(offset & 0x3);
 234 }
 235
 236 /*
 237  * Helper to check if a given instruction is a conditional branch
 238  * Derived from the conditional checks in analyse_instr()
 239  */
 240 bool is_conditional_branch(struct ppc_inst instr)
 241 {
 242         unsigned int opcode = ppc_inst_primary_opcode(instr);
 243
 244         if (opcode == 16)       /* bc, bca, bcl, bcla */
 245                 return true;
 246         if (opcode == 19) {
 247                 switch ((ppc_inst_val(instr) >> 1) & 0x3ff) {
 248                 case 16:        /* bclr, bclrl */
 249                 case 528:       /* bcctr, bcctrl */
 250                 case 560:       /* bctar, bctarl */
 251                         return true;
 252                 }
 253         }
 254         return false;
 255 }
 256 NOKPROBE_SYMBOL(is_conditional_branch);
 257
 258 int create_branch(struct ppc_inst *instr, const u32 *addr,
 259                   unsigned long target, int flags)
 260 {
 261         long offset;
 262
 263         *instr = ppc_inst(0);
 264         offset = target;
 265         if (! (flags & BRANCH_ABSOLUTE))
 266                 offset = offset - (unsigned long)addr;
 267
 268         /* Check we can represent the target in the instruction format */
 269         if (!is_offset_in_branch_range(offset))
 270                 return 1;
 271
 272         /* Mask out the flags and target, so they don't step on each other. */
 273         *instr = ppc_inst(0x48000000 | (flags & 0x3) | (offset & 0x03FFFFFC));
 274
 275         return 0;
 276 }
 277
 278 int create_cond_branch(struct ppc_inst *instr, const u32 *addr,
 279                        unsigned long target, int flags)
 280 {
 281         long offset;
 282
 283         offset = target;
 284         if (! (flags & BRANCH_ABSOLUTE))
 285                 offset = offset - (unsigned long)addr;
 286
 287         /* Check we can represent the target in the instruction format */
 288         if (!is_offset_in_cond_branch_range(offset))
 289                 return 1;
 290
 291         /* Mask out the flags and target, so they don't step on each other. */
 292         *instr = ppc_inst(0x40000000 | (flags & 0x3FF0003) | (offset & 0xFFFC));
 293
 294         return 0;
 295 }
 296
 297 static unsigned int branch_opcode(struct ppc_inst instr)
 298 {
 299         return ppc_inst_primary_opcode(instr) & 0x3F;
 300 }
 301
 302 static int instr_is_branch_iform(struct ppc_inst instr)
 303 {
 304         return branch_opcode(instr) == 18;
 305 }
 306
 307 static int instr_is_branch_bform(struct ppc_inst instr)
 308 {
 309         return branch_opcode(instr) == 16;
 310 }
 311
 312 int instr_is_relative_branch(struct ppc_inst instr)
 313 {
 314         if (ppc_inst_val(instr) & BRANCH_ABSOLUTE)
 315                 return 0;
 316
 317         return instr_is_branch_iform(instr) || instr_is_branch_bform(instr);
 318 }
 319
 320 int instr_is_relative_link_branch(struct ppc_inst instr)
 321 {
 322         return instr_is_relative_branch(instr) && (ppc_inst_val(instr) & BRANCH_SET_LINK);
 323 }
 324
 325 static unsigned long branch_iform_target(const u32 *instr)
 326 {
 327         signed long imm;
 328
 329         imm = ppc_inst_val(ppc_inst_read(instr)) & 0x3FFFFFC;
 330
 331         /* If the top bit of the immediate value is set this is negative */
 332         if (imm & 0x2000000)
 333                 imm -= 0x4000000;
 334
 335         if ((ppc_inst_val(ppc_inst_read(instr)) & BRANCH_ABSOLUTE) == 0)
 336                 imm += (unsigned long)instr;
 337
 338         return (unsigned long)imm;
 339 }
 340
 341 static unsigned long branch_bform_target(const u32 *instr)
 342 {
 343         signed long imm;
 344
 345         imm = ppc_inst_val(ppc_inst_read(instr)) & 0xFFFC;
 346
 347         /* If the top bit of the immediate value is set this is negative */
 348         if (imm & 0x8000)
 349                 imm -= 0x10000;
 350
 351         if ((ppc_inst_val(ppc_inst_read(instr)) & BRANCH_ABSOLUTE) == 0)
 352                 imm += (unsigned long)instr;
 353
 354         return (unsigned long)imm;
 355 }
 356
 357 unsigned long branch_target(const u32 *instr)
 358 {
 359         if (instr_is_branch_iform(ppc_inst_read(instr)))
 360                 return branch_iform_target(instr);
 361         else if (instr_is_branch_bform(ppc_inst_read(instr)))
 362                 return branch_bform_target(instr);
 363
 364         return 0;
 365 }
 366
 367 int translate_branch(struct ppc_inst *instr, const u32 *dest, const u32 *src)
 368 {
 369         unsigned long target;
 370         target = branch_target(src);
 371
 372         if (instr_is_branch_iform(ppc_inst_read(src)))
 373                 return create_branch(instr, dest, target,
 374                                      ppc_inst_val(ppc_inst_read(src)));
 375         else if (instr_is_branch_bform(ppc_inst_read(src)))
 376                 return create_cond_branch(instr, dest, target,
 377                                           ppc_inst_val(ppc_inst_read(src)));
 378
 379         return 1;
 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 int instr_is_branch_to_addr(const u32 *instr, unsigned long addr)
 401 {
 402         if (instr_is_branch_iform(ppc_inst_read(instr)) ||
 403             instr_is_branch_bform(ppc_inst_read(instr)))
 404                 return branch_target(instr) == addr;
 405
 406         return 0;
 407 }
 408
 409 static void __init test_trampoline(void)
 410 {
 411         asm ("nop;\n");
 412 }
 413
 414 #define check(x)        \
 415         if (!(x)) printk("code-patching: test failed at line %d\n", __LINE__);
 416
 417 static void __init test_branch_iform(void)
 418 {
 419         int err;
 420         struct ppc_inst instr;
 421         u32 tmp[2];
 422         u32 *iptr = tmp;
 423         unsigned long addr = (unsigned long)tmp;
 424
 425         /* The simplest case, branch to self, no flags */
 426         check(instr_is_branch_iform(ppc_inst(0x48000000)));
 427         /* All bits of target set, and flags */
 428         check(instr_is_branch_iform(ppc_inst(0x4bffffff)));
 429         /* High bit of opcode set, which is wrong */
 430         check(!instr_is_branch_iform(ppc_inst(0xcbffffff)));
 431         /* Middle bits of opcode set, which is wrong */
 432         check(!instr_is_branch_iform(ppc_inst(0x7bffffff)));
 433
 434         /* Simplest case, branch to self with link */
 435         check(instr_is_branch_iform(ppc_inst(0x48000001)));
 436         /* All bits of targets set */
 437         check(instr_is_branch_iform(ppc_inst(0x4bfffffd)));
 438         /* Some bits of targets set */
 439         check(instr_is_branch_iform(ppc_inst(0x4bff00fd)));
 440         /* Must be a valid branch to start with */
 441         check(!instr_is_branch_iform(ppc_inst(0x7bfffffd)));
 442
 443         /* Absolute branch to 0x100 */
 444         patch_instruction(iptr, ppc_inst(0x48000103));
 445         check(instr_is_branch_to_addr(iptr, 0x100));
 446         /* Absolute branch to 0x420fc */
 447         patch_instruction(iptr, ppc_inst(0x480420ff));
 448         check(instr_is_branch_to_addr(iptr, 0x420fc));
 449         /* Maximum positive relative branch, + 20MB - 4B */
 450         patch_instruction(iptr, ppc_inst(0x49fffffc));
 451         check(instr_is_branch_to_addr(iptr, addr + 0x1FFFFFC));
 452         /* Smallest negative relative branch, - 4B */
 453         patch_instruction(iptr, ppc_inst(0x4bfffffc));
 454         check(instr_is_branch_to_addr(iptr, addr - 4));
 455         /* Largest negative relative branch, - 32 MB */
 456         patch_instruction(iptr, ppc_inst(0x4a000000));
 457         check(instr_is_branch_to_addr(iptr, addr - 0x2000000));
 458
 459         /* Branch to self, with link */
 460         err = create_branch(&instr, iptr, addr, BRANCH_SET_LINK);
 461         patch_instruction(iptr, instr);
 462         check(instr_is_branch_to_addr(iptr, addr));
 463
 464         /* Branch to self - 0x100, with link */
 465         err = create_branch(&instr, iptr, addr - 0x100, BRANCH_SET_LINK);
 466         patch_instruction(iptr, instr);
 467         check(instr_is_branch_to_addr(iptr, addr - 0x100));
 468
 469         /* Branch to self + 0x100, no link */
 470         err = create_branch(&instr, iptr, addr + 0x100, 0);
 471         patch_instruction(iptr, instr);
 472         check(instr_is_branch_to_addr(iptr, addr + 0x100));
 473
 474         /* Maximum relative negative offset, - 32 MB */
 475         err = create_branch(&instr, iptr, addr - 0x2000000, BRANCH_SET_LINK);
 476         patch_instruction(iptr, instr);
 477         check(instr_is_branch_to_addr(iptr, addr - 0x2000000));
 478
 479         /* Out of range relative negative offset, - 32 MB + 4*/
 480         err = create_branch(&instr, iptr, addr - 0x2000004, BRANCH_SET_LINK);
 481         check(err);
 482
 483         /* Out of range relative positive offset, + 32 MB */
 484         err = create_branch(&instr, iptr, addr + 0x2000000, BRANCH_SET_LINK);
 485         check(err);
 486
 487         /* Unaligned target */
 488         err = create_branch(&instr, iptr, addr + 3, BRANCH_SET_LINK);
 489         check(err);
 490
 491         /* Check flags are masked correctly */
 492         err = create_branch(&instr, iptr, addr, 0xFFFFFFFC);
 493         patch_instruction(iptr, instr);
 494         check(instr_is_branch_to_addr(iptr, addr));
 495         check(ppc_inst_equal(instr, ppc_inst(0x48000000)));
 496 }
 497
 498 static void __init test_create_function_call(void)
 499 {
 500         u32 *iptr;
 501         unsigned long dest;
 502         struct ppc_inst instr;
 503
 504         /* Check we can create a function call */
 505         iptr = (u32 *)ppc_function_entry(test_trampoline);
 506         dest = ppc_function_entry(test_create_function_call);
 507         create_branch(&instr, iptr, dest, BRANCH_SET_LINK);
 508         patch_instruction(iptr, instr);
 509         check(instr_is_branch_to_addr(iptr, dest));
 510 }
 511
 512 static void __init test_branch_bform(void)
 513 {
 514         int err;
 515         unsigned long addr;
 516         struct ppc_inst instr;
 517         u32 tmp[2];
 518         u32 *iptr = tmp;
 519         unsigned int flags;
 520
 521         addr = (unsigned long)iptr;
 522
 523         /* The simplest case, branch to self, no flags */
 524         check(instr_is_branch_bform(ppc_inst(0x40000000)));
 525         /* All bits of target set, and flags */
 526         check(instr_is_branch_bform(ppc_inst(0x43ffffff)));
 527         /* High bit of opcode set, which is wrong */
 528         check(!instr_is_branch_bform(ppc_inst(0xc3ffffff)));
 529         /* Middle bits of opcode set, which is wrong */
 530         check(!instr_is_branch_bform(ppc_inst(0x7bffffff)));
 531
 532         /* Absolute conditional branch to 0x100 */
 533         patch_instruction(iptr, ppc_inst(0x43ff0103));
 534         check(instr_is_branch_to_addr(iptr, 0x100));
 535         /* Absolute conditional branch to 0x20fc */
 536         patch_instruction(iptr, ppc_inst(0x43ff20ff));
 537         check(instr_is_branch_to_addr(iptr, 0x20fc));
 538         /* Maximum positive relative conditional branch, + 32 KB - 4B */
 539         patch_instruction(iptr, ppc_inst(0x43ff7ffc));
 540         check(instr_is_branch_to_addr(iptr, addr + 0x7FFC));
 541         /* Smallest negative relative conditional branch, - 4B */
 542         patch_instruction(iptr, ppc_inst(0x43fffffc));
 543         check(instr_is_branch_to_addr(iptr, addr - 4));
 544         /* Largest negative relative conditional branch, - 32 KB */
 545         patch_instruction(iptr, ppc_inst(0x43ff8000));
 546         check(instr_is_branch_to_addr(iptr, addr - 0x8000));
 547
 548         /* All condition code bits set & link */
 549         flags = 0x3ff000 | BRANCH_SET_LINK;
 550
 551         /* Branch to self */
 552         err = create_cond_branch(&instr, iptr, addr, flags);
 553         patch_instruction(iptr, instr);
 554         check(instr_is_branch_to_addr(iptr, addr));
 555
 556         /* Branch to self - 0x100 */
 557         err = create_cond_branch(&instr, iptr, addr - 0x100, flags);
 558         patch_instruction(iptr, instr);
 559         check(instr_is_branch_to_addr(iptr, addr - 0x100));
 560
 561         /* Branch to self + 0x100 */
 562         err = create_cond_branch(&instr, iptr, addr + 0x100, flags);
 563         patch_instruction(iptr, instr);
 564         check(instr_is_branch_to_addr(iptr, addr + 0x100));
 565
 566         /* Maximum relative negative offset, - 32 KB */
 567         err = create_cond_branch(&instr, iptr, addr - 0x8000, flags);
 568         patch_instruction(iptr, instr);
 569         check(instr_is_branch_to_addr(iptr, addr - 0x8000));
 570
 571         /* Out of range relative negative offset, - 32 KB + 4*/
 572         err = create_cond_branch(&instr, iptr, addr - 0x8004, flags);
 573         check(err);
 574
 575         /* Out of range relative positive offset, + 32 KB */
 576         err = create_cond_branch(&instr, iptr, addr + 0x8000, flags);
 577         check(err);
 578
 579         /* Unaligned target */
 580         err = create_cond_branch(&instr, iptr, addr + 3, flags);
 581         check(err);
 582
 583         /* Check flags are masked correctly */
 584         err = create_cond_branch(&instr, iptr, addr, 0xFFFFFFFC);
 585         patch_instruction(iptr, instr);
 586         check(instr_is_branch_to_addr(iptr, addr));
 587         check(ppc_inst_equal(instr, ppc_inst(0x43FF0000)));
 588 }
 589
 590 static void __init test_translate_branch(void)
 591 {
 592         unsigned long addr;
 593         void *p, *q;
 594         struct ppc_inst instr;
 595         void *buf;
 596
 597         buf = vmalloc(PAGE_ALIGN(0x2000000 + 1));
 598         check(buf);
 599         if (!buf)
 600                 return;
 601
 602         /* Simple case, branch to self moved a little */
 603         p = buf;
 604         addr = (unsigned long)p;
 605         patch_branch(p, addr, 0);
 606         check(instr_is_branch_to_addr(p, addr));
 607         q = p + 4;
 608         translate_branch(&instr, q, p);
 609         patch_instruction(q, instr);
 610         check(instr_is_branch_to_addr(q, addr));
 611
 612         /* Maximum negative case, move b . to addr + 32 MB */
 613         p = buf;
 614         addr = (unsigned long)p;
 615         patch_branch(p, addr, 0);
 616         q = buf + 0x2000000;
 617         translate_branch(&instr, q, p);
 618         patch_instruction(q, instr);
 619         check(instr_is_branch_to_addr(p, addr));
 620         check(instr_is_branch_to_addr(q, addr));
 621         check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x4a000000)));
 622
 623         /* Maximum positive case, move x to x - 32 MB + 4 */
 624         p = buf + 0x2000000;
 625         addr = (unsigned long)p;
 626         patch_branch(p, addr, 0);
 627         q = buf + 4;
 628         translate_branch(&instr, q, p);
 629         patch_instruction(q, instr);
 630         check(instr_is_branch_to_addr(p, addr));
 631         check(instr_is_branch_to_addr(q, addr));
 632         check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x49fffffc)));
 633
 634         /* Jump to x + 16 MB moved to x + 20 MB */
 635         p = buf;
 636         addr = 0x1000000 + (unsigned long)buf;
 637         patch_branch(p, addr, BRANCH_SET_LINK);
 638         q = buf + 0x1400000;
 639         translate_branch(&instr, q, p);
 640         patch_instruction(q, instr);
 641         check(instr_is_branch_to_addr(p, addr));
 642         check(instr_is_branch_to_addr(q, addr));
 643
 644         /* Jump to x + 16 MB moved to x - 16 MB + 4 */
 645         p = buf + 0x1000000;
 646         addr = 0x2000000 + (unsigned long)buf;
 647         patch_branch(p, addr, 0);
 648         q = buf + 4;
 649         translate_branch(&instr, q, p);
 650         patch_instruction(q, instr);
 651         check(instr_is_branch_to_addr(p, addr));
 652         check(instr_is_branch_to_addr(q, addr));
 653
 654
 655         /* Conditional branch tests */
 656
 657         /* Simple case, branch to self moved a little */
 658         p = buf;
 659         addr = (unsigned long)p;
 660         create_cond_branch(&instr, p, addr, 0);
 661         patch_instruction(p, instr);
 662         check(instr_is_branch_to_addr(p, addr));
 663         q = buf + 4;
 664         translate_branch(&instr, q, p);
 665         patch_instruction(q, instr);
 666         check(instr_is_branch_to_addr(q, addr));
 667
 668         /* Maximum negative case, move b . to addr + 32 KB */
 669         p = buf;
 670         addr = (unsigned long)p;
 671         create_cond_branch(&instr, p, addr, 0xFFFFFFFC);
 672         patch_instruction(p, instr);
 673         q = buf + 0x8000;
 674         translate_branch(&instr, q, p);
 675         patch_instruction(q, instr);
 676         check(instr_is_branch_to_addr(p, addr));
 677         check(instr_is_branch_to_addr(q, addr));
 678         check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff8000)));
 679
 680         /* Maximum positive case, move x to x - 32 KB + 4 */
 681         p = buf + 0x8000;
 682         addr = (unsigned long)p;
 683         create_cond_branch(&instr, p, addr, 0xFFFFFFFC);
 684         patch_instruction(p, instr);
 685         q = buf + 4;
 686         translate_branch(&instr, q, p);
 687         patch_instruction(q, instr);
 688         check(instr_is_branch_to_addr(p, addr));
 689         check(instr_is_branch_to_addr(q, addr));
 690         check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff7ffc)));
 691
 692         /* Jump to x + 12 KB moved to x + 20 KB */
 693         p = buf;
 694         addr = 0x3000 + (unsigned long)buf;
 695         create_cond_branch(&instr, p, addr, BRANCH_SET_LINK);
 696         patch_instruction(p, instr);
 697         q = buf + 0x5000;
 698         translate_branch(&instr, q, p);
 699         patch_instruction(q, instr);
 700         check(instr_is_branch_to_addr(p, addr));
 701         check(instr_is_branch_to_addr(q, addr));
 702
 703         /* Jump to x + 8 KB moved to x - 8 KB + 4 */
 704         p = buf + 0x2000;
 705         addr = 0x4000 + (unsigned long)buf;
 706         create_cond_branch(&instr, p, addr, 0);
 707         patch_instruction(p, instr);
 708         q = buf + 4;
 709         translate_branch(&instr, q, p);
 710         patch_instruction(q, instr);
 711         check(instr_is_branch_to_addr(p, addr));
 712         check(instr_is_branch_to_addr(q, addr));
 713
 714         /* Free the buffer we were using */
 715         vfree(buf);
 716 }
 717
 718 #ifdef CONFIG_PPC64
 719 static void __init test_prefixed_patching(void)
 720 {
 721         extern unsigned int code_patching_test1[];
 722         extern unsigned int code_patching_test1_expected[];
 723         extern unsigned int end_code_patching_test1[];
 724
 725         __patch_instruction(code_patching_test1,
 726                             ppc_inst_prefix(OP_PREFIX << 26, 0x00000000),
 727                             code_patching_test1);
 728
 729         check(!memcmp(code_patching_test1,
 730                       code_patching_test1_expected,
 731                       sizeof(unsigned int) *
 732                       (end_code_patching_test1 - code_patching_test1)));
 733 }
 734 #else
 735 static inline void test_prefixed_patching(void) {}
 736 #endif
 737
 738 static int __init test_code_patching(void)
 739 {
 740         printk(KERN_DEBUG "Running code patching self-tests ...\n");
 741
 742         test_branch_iform();
 743         test_branch_bform();
 744         test_create_function_call();
 745         test_translate_branch();
 746         test_prefixed_patching();
 747
 748         return 0;
 749 }
 750 late_initcall(test_code_patching);
 751
 752 #endif /* CONFIG_CODE_PATCHING_SELFTEST */