arch/powerpc/include/asm/cpu_has_feature.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __ASM_POWERPC_CPU_HAS_FEATURE_H
   3 #define __ASM_POWERPC_CPU_HAS_FEATURE_H
   4
   5 #ifndef __ASSEMBLY__
   6
   7 #include <linux/bug.h>
   8 #include <asm/cputable.h>
   9
  10 static __always_inline bool early_cpu_has_feature(unsigned long feature)
  11 {
  12         return !!((CPU_FTRS_ALWAYS & feature) ||
  13                   (CPU_FTRS_POSSIBLE & cur_cpu_spec->cpu_features & feature));
  14 }
  15
  16 #ifdef CONFIG_JUMP_LABEL_FEATURE_CHECKS
  17 #include <linux/jump_label.h>
  18
  19 #define NUM_CPU_FTR_KEYS        BITS_PER_LONG
  20
  21 extern struct static_key_true cpu_feature_keys[NUM_CPU_FTR_KEYS];
  22
  23 static __always_inline bool cpu_has_feature(unsigned long feature)
  24 {
  25         int i;
  26
  27         BUILD_BUG_ON(!__builtin_constant_p(feature));
  28         BUILD_BUG_ON(__builtin_popcountl(feature) > 1);
  29
  30 #ifdef CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG
  31         if (!static_key_feature_checks_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 __always_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_CPU_HAS_FEATURE_H */