Re: [PATCH 06/19] riscv: Extend cpufeature.c to detect vendor extensions
From: kernel test robot
Date: Fri Apr 12 2024 - 10:44:53 EST
Hi Charlie,
kernel test robot noticed the following build warnings:
[auto build test WARNING on 4cece764965020c22cff7665b18a012006359095]
url: https://github.com/intel-lab-lkp/linux/commits/Charlie-Jenkins/dt-bindings-riscv-Add-vendorid-and-archid/20240412-121709
base: 4cece764965020c22cff7665b18a012006359095
patch link: https://lore.kernel.org/r/20240411-dev-charlie-support_thead_vector_6_9-v1-6-4af9815ec746%40rivosinc.com
patch subject: [PATCH 06/19] riscv: Extend cpufeature.c to detect vendor extensions
config: riscv-defconfig (https://download.01.org/0day-ci/archive/20240412/202404122206.TkXKhj29-lkp@xxxxxxxxx/config)
compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project 8b3b4a92adee40483c27f26c478a384cd69c6f05)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240412/202404122206.TkXKhj29-lkp@xxxxxxxxx/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@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202404122206.TkXKhj29-lkp@xxxxxxxxx/
All warnings (new ones prefixed by >>):
In file included from arch/riscv/kernel/cpufeature.c:20:
In file included from arch/riscv/include/asm/cacheflush.h:9:
In file included from include/linux/mm.h:2208:
include/linux/vmstat.h:522:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
522 | return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
| ~~~~~~~~~~~ ^ ~~~
>> arch/riscv/kernel/cpufeature.c:395:4: warning: label followed by a declaration is a C23 extension [-Wc23-extensions]
395 | bool found;
| ^
2 warnings generated.
vim +395 arch/riscv/kernel/cpufeature.c
370
371 static void __init riscv_parse_isa_string(unsigned long *this_hwcap, struct riscv_isainfo *isainfo,
372 struct riscv_isainfo *isavendorinfo, unsigned long vendorid,
373 unsigned long *isa2hwcap, const char *isa)
374 {
375 /*
376 * For all possible cpus, we have already validated in
377 * the boot process that they at least contain "rv" and
378 * whichever of "32"/"64" this kernel supports, and so this
379 * section can be skipped.
380 */
381 isa += 4;
382
383 while (*isa) {
384 const char *ext = isa++;
385 const char *ext_end = isa;
386 bool ext_long = false, ext_err = false;
387 struct riscv_isainfo *selected_isainfo = isainfo;
388 const struct riscv_isa_ext_data *selected_riscv_isa_ext = riscv_isa_ext;
389 size_t selected_riscv_isa_ext_count = riscv_isa_ext_count;
390 unsigned int id_offset = 0;
391
392 switch (*ext) {
393 case 'x':
394 case 'X':
> 395 bool found;
396
397 found = get_isa_vendor_ext(vendorid,
398 &selected_riscv_isa_ext,
399 &selected_riscv_isa_ext_count);
400 selected_isainfo = isavendorinfo;
401 id_offset = RISCV_ISA_VENDOR_EXT_BASE;
402 if (!found) {
403 pr_warn("No associated vendor extensions with vendor id: %lx\n",
404 vendorid);
405 for (; *isa && *isa != '_'; ++isa)
406 ;
407 ext_err = true;
408 break;
409 }
410 fallthrough;
411 case 's':
412 /*
413 * Workaround for invalid single-letter 's' & 'u' (QEMU).
414 * No need to set the bit in riscv_isa as 's' & 'u' are
415 * not valid ISA extensions. It works unless the first
416 * multi-letter extension in the ISA string begins with
417 * "Su" and is not prefixed with an underscore.
418 */
419 if (ext[-1] != '_' && ext[1] == 'u') {
420 ++isa;
421 ext_err = true;
422 break;
423 }
424 fallthrough;
425 case 'S':
426 case 'z':
427 case 'Z':
428 /*
429 * Before attempting to parse the extension itself, we find its end.
430 * As multi-letter extensions must be split from other multi-letter
431 * extensions with an "_", the end of a multi-letter extension will
432 * either be the null character or the "_" at the start of the next
433 * multi-letter extension.
434 *
435 * Next, as the extensions version is currently ignored, we
436 * eliminate that portion. This is done by parsing backwards from
437 * the end of the extension, removing any numbers. This may be a
438 * major or minor number however, so the process is repeated if a
439 * minor number was found.
440 *
441 * ext_end is intended to represent the first character *after* the
442 * name portion of an extension, but will be decremented to the last
443 * character itself while eliminating the extensions version number.
444 * A simple re-increment solves this problem.
445 */
446 ext_long = true;
447 for (; *isa && *isa != '_'; ++isa)
448 if (unlikely(!isalnum(*isa)))
449 ext_err = true;
450
451 ext_end = isa;
452 if (unlikely(ext_err))
453 break;
454
455 if (!isdigit(ext_end[-1]))
456 break;
457
458 while (isdigit(*--ext_end))
459 ;
460
461 if (tolower(ext_end[0]) != 'p' || !isdigit(ext_end[-1])) {
462 ++ext_end;
463 break;
464 }
465
466 while (isdigit(*--ext_end))
467 ;
468
469 ++ext_end;
470 break;
471 default:
472 /*
473 * Things are a little easier for single-letter extensions, as they
474 * are parsed forwards.
475 *
476 * After checking that our starting position is valid, we need to
477 * ensure that, when isa was incremented at the start of the loop,
478 * that it arrived at the start of the next extension.
479 *
480 * If we are already on a non-digit, there is nothing to do. Either
481 * we have a multi-letter extension's _, or the start of an
482 * extension.
483 *
484 * Otherwise we have found the current extension's major version
485 * number. Parse past it, and a subsequent p/minor version number
486 * if present. The `p` extension must not appear immediately after
487 * a number, so there is no fear of missing it.
488 *
489 */
490 if (unlikely(!isalpha(*ext))) {
491 ext_err = true;
492 break;
493 }
494
495 if (!isdigit(*isa))
496 break;
497
498 while (isdigit(*++isa))
499 ;
500
501 if (tolower(*isa) != 'p')
502 break;
503
504 if (!isdigit(*++isa)) {
505 --isa;
506 break;
507 }
508
509 while (isdigit(*++isa))
510 ;
511
512 break;
513 }
514
515 /*
516 * The parser expects that at the start of an iteration isa points to the
517 * first character of the next extension. As we stop parsing an extension
518 * on meeting a non-alphanumeric character, an extra increment is needed
519 * where the succeeding extension is a multi-letter prefixed with an "_".
520 */
521 if (*isa == '_')
522 ++isa;
523
524 if (unlikely(ext_err))
525 continue;
526 if (!ext_long) {
527 int nr = tolower(*ext) - 'a';
528
529 if (riscv_isa_extension_check(nr)) {
530 *this_hwcap |= isa2hwcap[nr];
531 set_bit(nr, isainfo->isa);
532 }
533 } else {
534 for (int i = 0; i < selected_riscv_isa_ext_count; i++)
535 match_isa_ext(&selected_riscv_isa_ext[i], ext,
536 ext_end, selected_isainfo,
537 id_offset);
538 }
539 }
540 }
541
--
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