From: kernel test robot <lkp@intel.com>
To: "Mike Rapoport (IBM)" <rppt@kernel.org>
Cc: llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev,
Mike Rapoport <rppt@kernel.org>
Subject: [rppt:execmem/x86-rox/rfc-v2 21/25] arch/x86/kernel/alternative.c:417:17: error: call to undeclared function 'module_writable_address'; ISO C99 and later do not support implicit function declarations
Date: Mon, 6 May 2024 23:43:06 +0800 [thread overview]
Message-ID: <202405062340.eU4eWKR3-lkp@intel.com> (raw)
tree: https://git.kernel.org/pub/scm/linux/kernel/git/rppt/linux.git execmem/x86-rox/rfc-v2
head: 0caa8ac5e8f2f6de2e75cd2ddd552e8756779944
commit: 4527045f6e1892edac12176b8d82094c35427cdf [21/25] x86/module: perpare module loading for ROX allocations of text
config: x86_64-allnoconfig (https://download.01.org/0day-ci/archive/20240506/202405062340.eU4eWKR3-lkp@intel.com/config)
compiler: clang version 18.1.4 (https://github.com/llvm/llvm-project e6c3289804a67ea0bb6a86fadbe454dd93b8d855)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240506/202405062340.eU4eWKR3-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202405062340.eU4eWKR3-lkp@intel.com/
All errors (new ones prefixed by >>):
>> arch/x86/kernel/alternative.c:417:17: error: call to undeclared function 'module_writable_address'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
417 | u8 *wr_instr = module_writable_address(mod, instr);
| ^
>> arch/x86/kernel/alternative.c:417:6: error: incompatible integer to pointer conversion initializing 'u8 *' (aka 'unsigned char *') with an expression of type 'int' [-Wint-conversion]
417 | u8 *wr_instr = module_writable_address(mod, instr);
| ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/x86/kernel/alternative.c:500:14: error: call to undeclared function 'module_writable_address'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
500 | wr_instr = module_writable_address(mod, instr);
| ^
>> arch/x86/kernel/alternative.c:500:12: error: incompatible integer to pointer conversion assigning to 'u8 *' (aka 'unsigned char *') from 'int' [-Wint-conversion]
500 | wr_instr = module_writable_address(mod, instr);
| ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/x86/kernel/alternative.c:503:18: error: incompatible integer to pointer conversion assigning to 'u8 *' (aka 'unsigned char *') from 'int' [-Wint-conversion]
503 | wr_replacement = module_writable_address(mod, replacement);
| ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
5 errors generated.
vim +/module_writable_address +417 arch/x86/kernel/alternative.c
409
410 /*
411 * Rewrite the "call BUG_func" replacement to point to the target of the
412 * indirect pv_ops call "call *disp(%ip)".
413 */
414 static int alt_replace_call(u8 *instr, u8 *insn_buff, struct alt_instr *a,
415 struct module *mod)
416 {
> 417 u8 *wr_instr = module_writable_address(mod, instr);
418 void *target, *bug = &BUG_func;
419 s32 disp;
420
421 if (a->replacementlen != 5 || insn_buff[0] != CALL_INSN_OPCODE) {
422 pr_err("ALT_FLAG_DIRECT_CALL set for a non-call replacement instruction\n");
423 BUG();
424 }
425
426 if (a->instrlen != 6 ||
427 wr_instr[0] != CALL_RIP_REL_OPCODE ||
428 wr_instr[1] != CALL_RIP_REL_MODRM) {
429 pr_err("ALT_FLAG_DIRECT_CALL set for unrecognized indirect call\n");
430 BUG();
431 }
432
433 /* Skip CALL_RIP_REL_OPCODE and CALL_RIP_REL_MODRM */
434 disp = *(s32 *)(wr_instr + 2);
435 #ifdef CONFIG_X86_64
436 /* ff 15 00 00 00 00 call *0x0(%rip) */
437 /* target address is stored at "next instruction + disp". */
438 target = *(void **)(instr + a->instrlen + disp);
439 #else
440 /* ff 15 00 00 00 00 call *0x0 */
441 /* target address is stored at disp. */
442 target = *(void **)disp;
443 #endif
444 if (!target)
445 target = bug;
446
447 /* (BUG_func - .) + (target - BUG_func) := target - . */
448 *(s32 *)(insn_buff + 1) += target - bug;
449
450 if (target == &nop_func)
451 return 0;
452
453 return 5;
454 }
455
456 /*
457 * Replace instructions with better alternatives for this CPU type. This runs
458 * before SMP is initialized to avoid SMP problems with self modifying code.
459 * This implies that asymmetric systems where APs have less capabilities than
460 * the boot processor are not handled. Tough. Make sure you disable such
461 * features by hand.
462 *
463 * Marked "noinline" to cause control flow change and thus insn cache
464 * to refetch changed I$ lines.
465 */
466 void __init_or_module noinline apply_alternatives(struct alt_instr *start,
467 struct alt_instr *end,
468 struct module *mod)
469 {
470 struct alt_instr *a;
471 u8 *instr, *replacement;
472 u8 insn_buff[MAX_PATCH_LEN];
473
474 DPRINTK(ALT, "alt table %px, -> %px", start, end);
475
476 /*
477 * In the case CONFIG_X86_5LEVEL=y, KASAN_SHADOW_START is defined using
478 * cpu_feature_enabled(X86_FEATURE_LA57) and is therefore patched here.
479 * During the process, KASAN becomes confused seeing partial LA57
480 * conversion and triggers a false-positive out-of-bound report.
481 *
482 * Disable KASAN until the patching is complete.
483 */
484 kasan_disable_current();
485
486 /*
487 * The scan order should be from start to end. A later scanned
488 * alternative code can overwrite previously scanned alternative code.
489 * Some kernel functions (e.g. memcpy, memset, etc) use this order to
490 * patch code.
491 *
492 * So be careful if you want to change the scan order to any other
493 * order.
494 */
495 for (a = start; a < end; a++) {
496 int insn_buff_sz = 0;
497 u8 *wr_instr, *wr_replacement;
498
499 instr = (u8 *)&a->instr_offset + a->instr_offset;
> 500 wr_instr = module_writable_address(mod, instr);
501
502 replacement = (u8 *)&a->repl_offset + a->repl_offset;
503 wr_replacement = module_writable_address(mod, replacement);
504
505 BUG_ON(a->instrlen > sizeof(insn_buff));
506 BUG_ON(a->cpuid >= (NCAPINTS + NBUGINTS) * 32);
507
508 /*
509 * Patch if either:
510 * - feature is present
511 * - feature not present but ALT_FLAG_NOT is set to mean,
512 * patch if feature is *NOT* present.
513 */
514 if (!boot_cpu_has(a->cpuid) == !(a->flags & ALT_FLAG_NOT)) {
515 optimize_nops_inplace(wr_instr, a->instrlen);
516 continue;
517 }
518
519 DPRINTK(ALT, "feat: %d*32+%d, old: (%pS (%px) len: %d), repl: (%px, len: %d) flags: 0x%x",
520 a->cpuid >> 5,
521 a->cpuid & 0x1f,
522 instr, instr, a->instrlen,
523 replacement, a->replacementlen, a->flags);
524
525 memcpy(insn_buff, wr_replacement, a->replacementlen);
526 insn_buff_sz = a->replacementlen;
527
528 if (a->flags & ALT_FLAG_DIRECT_CALL) {
529 insn_buff_sz = alt_replace_call(instr, insn_buff, a,
530 mod);
531 if (insn_buff_sz < 0)
532 continue;
533 }
534
535 for (; insn_buff_sz < a->instrlen; insn_buff_sz++)
536 insn_buff[insn_buff_sz] = 0x90;
537
538 apply_relocation(insn_buff, a->instrlen, instr, replacement, a->replacementlen);
539
540 DUMP_BYTES(ALT, wr_instr, a->instrlen, "%px: old_insn: ", instr);
541 DUMP_BYTES(ALT, replacement, a->replacementlen, "%px: rpl_insn: ", replacement);
542 DUMP_BYTES(ALT, insn_buff, insn_buff_sz, "%px: final_insn: ", instr);
543
544 text_poke_early(wr_instr, insn_buff, insn_buff_sz);
545 }
546
547 kasan_enable_current();
548 }
549
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
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