[jlayton:uek-localio 2024/2262] arch/x86/kernel/cpu/intel.c:568:34: warning: result of comparison of constant 1615 with expression of type '__u8' (aka 'unsigned char') is always false

[jlayton:uek-localio 2024/2262] arch/x86/kernel/cpu/intel.c:568:34: warning: result of comparison of constant 1615 with expression of type '__u8' (aka 'unsigned char') is always false

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux.git uek-localio
head:   65b0dc6bb1f5c18e63d8ee9ea1cca997456a81a9
commit: ae99e2e456aca980ec40e20ac1ca7e079330f058 [2024/2262] x86/cpu/intel: enable X86_FEATURE_NT_GOOD on Intel Broadwellx
config: x86_64-buildonly-randconfig-006-20250524 (https://download.01.org/0day-ci/archive/20250524/202505241420.0BIAggEz-lkp@intel.com/config)
compiler: clang version 20.1.2 (https://github.com/llvm/llvm-project 58df0ef89dd64126512e4ee27b4ac3fd8ddf6247)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250524/202505241420.0BIAggEz-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/202505241420.0BIAggEz-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> arch/x86/kernel/cpu/intel.c:568:34: warning: result of comparison of constant 1615 with expression of type '__u8' (aka 'unsigned char') is always false [-Wtautological-constant-out-of-range-compare]
     568 |         if (c->x86 == 6 && c->x86_model == INTEL_BROADWELL_X)
         |                            ~~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~~~~
   1 warning generated.


vim +568 arch/x86/kernel/cpu/intel.c

   523	
   524	static void init_intel(struct cpuinfo_x86 *c)
   525	{
   526		early_init_intel(c);
   527	
   528		intel_workarounds(c);
   529	
   530		init_intel_cacheinfo(c);
   531	
   532		if (c->cpuid_level > 9) {
   533			unsigned eax = cpuid_eax(10);
   534			/* Check for version and the number of counters */
   535			if ((eax & 0xff) && (((eax>>8) & 0xff) > 1))
   536				set_cpu_cap(c, X86_FEATURE_ARCH_PERFMON);
   537		}
   538	
   539		if (cpu_has(c, X86_FEATURE_XMM2))
   540			set_cpu_cap(c, X86_FEATURE_LFENCE_RDTSC);
   541	
   542		if (boot_cpu_has(X86_FEATURE_DS)) {
   543			unsigned int l1, l2;
   544	
   545			rdmsr(MSR_IA32_MISC_ENABLE, l1, l2);
   546			if (!(l1 & MSR_IA32_MISC_ENABLE_BTS_UNAVAIL))
   547				set_cpu_cap(c, X86_FEATURE_BTS);
   548			if (!(l1 & MSR_IA32_MISC_ENABLE_PEBS_UNAVAIL))
   549				set_cpu_cap(c, X86_FEATURE_PEBS);
   550		}
   551	
   552		if (boot_cpu_has(X86_FEATURE_CLFLUSH) &&
   553		    (c->x86_vfm == INTEL_CORE2_DUNNINGTON ||
   554		     c->x86_vfm == INTEL_NEHALEM_EX ||
   555		     c->x86_vfm == INTEL_WESTMERE_EX))
   556			set_cpu_bug(c, X86_BUG_CLFLUSH_MONITOR);
   557	
   558		if (boot_cpu_has(X86_FEATURE_MWAIT) &&
   559		    (c->x86_vfm == INTEL_ATOM_GOLDMONT ||
   560		     c->x86_vfm == INTEL_LUNARLAKE_M))
   561			set_cpu_bug(c, X86_BUG_MONITOR);
   562	
   563	#ifdef CONFIG_X86_64
   564		if (c->x86 == 15)
   565			c->x86_cache_alignment = c->x86_clflush_size * 2;
   566		if (c->x86 == 6)
   567			set_cpu_cap(c, X86_FEATURE_REP_GOOD);
 > 568		if (c->x86 == 6 && c->x86_model == INTEL_BROADWELL_X)
   569			set_cpu_cap(c, X86_FEATURE_NT_GOOD);
   570	#else
   571		/*
   572		 * Names for the Pentium II/Celeron processors
   573		 * detectable only by also checking the cache size.
   574		 * Dixon is NOT a Celeron.
   575		 */
   576		if (c->x86 == 6) {
   577			unsigned int l2 = c->x86_cache_size;
   578			char *p = NULL;
   579	
   580			switch (c->x86_model) {
   581			case 5:
   582				if (l2 == 0)
   583					p = "Celeron (Covington)";
   584				else if (l2 == 256)
   585					p = "Mobile Pentium II (Dixon)";
   586				break;
   587	
   588			case 6:
   589				if (l2 == 128)
   590					p = "Celeron (Mendocino)";
   591				else if (c->x86_stepping == 0 || c->x86_stepping == 5)
   592					p = "Celeron-A";
   593				break;
   594	
   595			case 8:
   596				if (l2 == 128)
   597					p = "Celeron (Coppermine)";
   598				break;
   599			}
   600	
   601			if (p)
   602				strcpy(c->x86_model_id, p);
   603		}
   604	#endif
   605	
   606		/* Work around errata */
   607		srat_detect_node(c);
   608	
   609		init_ia32_feat_ctl(c);
   610	
   611		init_intel_misc_features(c);
   612	
   613		split_lock_init();
   614	
   615		intel_init_thermal(c);
   616	}
   617	

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https://github.com/intel/lkp-tests/wiki