arch/powerpc/include/asm/cpu_has_feature.h

   1 #ifndef __ASM_POWERPC_CPUFEATURES_H
   2 #define __ASM_POWERPC_CPUFEATURES_H
   3
   4 #ifndef __ASSEMBLY__
   5
   6 #include <linux/bug.h>
   7 #include <asm/cputable.h>
   8
   9 static inline bool early_cpu_has_feature(unsigned long feature)
  10 {
  11         return !!((CPU_FTRS_ALWAYS & feature) ||
  12                   (CPU_FTRS_POSSIBLE & cur_cpu_spec->cpu_features & feature));
  13 }
  14
  15 #ifdef CONFIG_JUMP_LABEL_FEATURE_CHECKS
  16 #include <linux/jump_label.h>
  17
  18 #define NUM_CPU_FTR_KEYS        BITS_PER_LONG
  19
  20 extern struct static_key_true cpu_feature_keys[NUM_CPU_FTR_KEYS];
  21
  22 static __always_inline bool cpu_has_feature(unsigned long feature)
  23 {
  24         int i;
  25
  26 #ifndef __clang__ /* clang can't cope with this */
  27         BUILD_BUG_ON(!__builtin_constant_p(feature));
  28 #endif
  29
  30 #ifdef CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG
  31         if (!static_key_initialized) {
  32                 printk("Warning! cpu_has_feature() used prior to jump label init!\n");
  33                 dump_stack();
  34                 return early_cpu_has_feature(feature);
  35         }
  36 #endif
  37
  38         if (CPU_FTRS_ALWAYS & feature)
  39                 return true;
  40
  41         if (!(CPU_FTRS_POSSIBLE & feature))
  42                 return false;
  43
  44         i = __builtin_ctzl(feature);
  45         return static_branch_likely(&cpu_feature_keys[i]);
  46 }
  47 #else
  48 static inline bool cpu_has_feature(unsigned long feature)
  49 {
  50         return early_cpu_has_feature(feature);
  51 }
  52 #endif
  53
  54 #endif /* __ASSEMBLY__ */
  55 #endif /* __ASM_POWERPC_CPUFEATURE_H */