tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: 0e1980c40b6edfa68b6acf926bab22448a6e40c9 commit: 6ba3d5014d24a46ed329fc567e554c218eb62cfa [2654/3060] ARM: Emulate one-byte cmpxchg config: arm-randconfig-r051-20240602 (https://download.01.org/0day-ci/archive/20240602/202406021249.imvU1Clu-lkp@xxxxxxxxx/config) compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project bafda89a0944d947fc4b3b5663185e07a397ac30) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240602/202406021249.imvU1Clu-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/202406021249.imvU1Clu-lkp@xxxxxxxxx/ All errors (new ones prefixed by >>): In file included from kernel/bounds.c:13: In file included from include/linux/log2.h:12: In file included from include/linux/bitops.h:63: In file included from arch/arm/include/asm/bitops.h:245: In file included from include/asm-generic/bitops/lock.h:5: In file included from include/linux/atomic.h:7: In file included from arch/arm/include/asm/atomic.h:16: >> arch/arm/include/asm/cmpxchg.h:167:12: error: call to undeclared function 'cmpxchg_emu_u8'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 167 | oldval = cmpxchg_emu_u8((volatile u8 *)ptr, old, new); | ^ 1 error generated. make[3]: *** [scripts/Makefile.build:117: kernel/bounds.s] Error 1 make[3]: Target 'prepare' not remade because of errors. make[2]: *** [Makefile:1208: prepare0] Error 2 make[2]: Target 'prepare' not remade because of errors. make[1]: *** [Makefile:240: __sub-make] Error 2 make[1]: Target 'prepare' not remade because of errors. make: *** [Makefile:240: __sub-make] Error 2 make: Target 'prepare' not remade because of errors. vim +/cmpxchg_emu_u8 +167 arch/arm/include/asm/cmpxchg.h 152 153 /* 154 * cmpxchg only support 32-bits operands on ARMv6. 155 */ 156 157 static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old, 158 unsigned long new, int size) 159 { 160 unsigned long oldval, res; 161 162 prefetchw((const void *)ptr); 163 164 switch (size) { 165 #ifdef CONFIG_CPU_V6 /* min ARCH >= ARMv6K */ 166 case 1: > 167 oldval = cmpxchg_emu_u8((volatile u8 *)ptr, old, new); 168 break; 169 #else 170 case 1: 171 do { 172 asm volatile("@ __cmpxchg1\n" 173 " ldrexb %1, [%2]\n" 174 " mov %0, #0\n" 175 " teq %1, %3\n" 176 " strexbeq %0, %4, [%2]\n" 177 : "=&r" (res), "=&r" (oldval) 178 : "r" (ptr), "Ir" (old), "r" (new) 179 : "memory", "cc"); 180 } while (res); 181 break; 182 case 2: 183 do { 184 asm volatile("@ __cmpxchg1\n" 185 " ldrexh %1, [%2]\n" 186 " mov %0, #0\n" 187 " teq %1, %3\n" 188 " strexheq %0, %4, [%2]\n" 189 : "=&r" (res), "=&r" (oldval) 190 : "r" (ptr), "Ir" (old), "r" (new) 191 : "memory", "cc"); 192 } while (res); 193 break; 194 #endif 195 case 4: 196 do { 197 asm volatile("@ __cmpxchg4\n" 198 " ldrex %1, [%2]\n" 199 " mov %0, #0\n" 200 " teq %1, %3\n" 201 " strexeq %0, %4, [%2]\n" 202 : "=&r" (res), "=&r" (oldval) 203 : "r" (ptr), "Ir" (old), "r" (new) 204 : "memory", "cc"); 205 } while (res); 206 break; 207 default: 208 __bad_cmpxchg(ptr, size); 209 oldval = 0; 210 } 211 212 return oldval; 213 } 214 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
