Quelle  cpu_has_feature.h   Sprache: C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __ASM_POWERPC_CPU_HAS_FEATURE_H
#define __ASM_POWERPC_CPU_HAS_FEATURE_H

#ifndef __ASSEMBLY__

#include <linux/bug.h>
#include <asm/cputable.h>

static __always_inline bool early_cpu_has_feature(unsigned long feature)
{
 return !!((CPU_FTRS_ALWAYS & feature) ||
    (CPU_FTRS_POSSIBLE & cur_cpu_spec->cpu_features & feature));
}

#ifdef CONFIG_JUMP_LABEL_FEATURE_CHECKS
#include <linux/jump_label.h>

#define NUM_CPU_FTR_KEYS BITS_PER_LONG

extern struct static_key_true cpu_feature_keys[NUM_CPU_FTR_KEYS];

static __always_inline bool cpu_has_feature(unsigned long feature)
{
 int i;

 BUILD_BUG_ON(!__builtin_constant_p(feature));
 BUILD_BUG_ON(__builtin_popcountl(feature) > 1);

#ifdef CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG
 if (!static_key_feature_checks_initialized) {
  printk("Warning! cpu_has_feature() used prior to jump label init!\n");
  dump_stack();
  return early_cpu_has_feature(feature);
 }
#endif

 if (CPU_FTRS_ALWAYS & feature)
  return true;

 if (!(CPU_FTRS_POSSIBLE & feature))
  return false;

 i = __builtin_ctzl(feature);
 return static_branch_likely(&cpu_feature_keys[i]);
}
#else
static __always_inline bool cpu_has_feature(unsigned long feature)
{
 return early_cpu_has_feature(feature);
}
#endif

#endif /* __ASSEMBLY__ */
#endif /* __ASM_POWERPC_CPU_HAS_FEATURE_H */