tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 06a4ec1d9dc652e17ee3ac2ceb6c7cf6c2b75cdd commit: c9b0299034665d594e56ee343f28033d1b24de6d MIPS: Use fallthrough for arch/mips date: 3 months ago config: mips-randconfig-m031-20200818 (attached as .config) compiler: mips-linux-gcc (GCC) 9.3.0 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; New smatch warnings: arch/mips/include/asm/fpu.h:79 __enable_fpu() warn: ignoring unreachable code. arch/mips/include/asm/fpu.h:79 __enable_fpu() warn: ignoring unreachable code. Old smatch warnings: arch/mips/kernel/traps.c:1914 nmi_exception_handler() warn: ignoring unreachable code. # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout c9b0299034665d594e56ee343f28033d1b24de6d vim +79 arch/mips/include/asm/fpu.h 53 54 static inline int __enable_fpu(enum fpu_mode mode) 55 { 56 int fr; 57 58 switch (mode) { 59 case FPU_AS_IS: 60 /* just enable the FPU in its current mode */ 61 set_c0_status(ST0_CU1); 62 enable_fpu_hazard(); 63 return 0; 64 65 case FPU_HYBRID: 66 if (!cpu_has_fre) 67 return SIGFPE; 68 69 /* set FRE */ 70 set_c0_config5(MIPS_CONF5_FRE); 71 goto fr_common; 72 73 case FPU_64BIT: 74 #if !(defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR6) \ 75 || defined(CONFIG_64BIT)) 76 /* we only have a 32-bit FPU */ 77 return SIGFPE; 78 #endif 80 case FPU_32BIT: 81 if (cpu_has_fre) { 82 /* clear FRE */ 83 clear_c0_config5(MIPS_CONF5_FRE); 84 } 85 fr_common: 86 /* set CU1 & change FR appropriately */ 87 fr = (int)mode & FPU_FR_MASK; 88 change_c0_status(ST0_CU1 | ST0_FR, ST0_CU1 | (fr ? ST0_FR : 0)); 89 enable_fpu_hazard(); 90 91 /* check FR has the desired value */ 92 if (!!(read_c0_status() & ST0_FR) == !!fr) 93 return 0; 94 95 /* unsupported FR value */ 96 __disable_fpu(); 97 return SIGFPE; 98 99 default: 100 BUG(); 101 } 102 103 return SIGFPE; 104 } 105 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org